Bio

Academic Appointments


Administrative Appointments


  • Co-Director, Stanford-NASA National Biocomputation Center, Stanford University (1997 - 2007)
  • Director Craniofacail Anomalies Center, LPCH (1992 - 2007)
  • Chief Pediatric Surgery, LPCH (1997 - 2005)
  • Chairman, Department of Functional Restoration, Stanford University Medical School (1994 - 2001)
  • Head Division of Plastic Surgery, Stanford university medical School (1992 - 2002)

Honors & Awards


  • Chauteaubriand Fellowship, French Government (1987)
  • Distinguished Alumnus, St Olaf College (1992)
  • Fulbright Fellow, France, Fulbright Foundation (1980)

Research & Scholarship

Current Research and Scholarly Interests


Surgical correction and the study of growth and development of craniomaxillofacial anomalies and deformities.

1. Histochemical Analysis of Facial Muscles.
2. Cranial Sutural Manipulation.
3. Stability of Mandibular and Maxillary Surgery
4. Growth Factors in Infant Cranial Sutures.
5. Virtual Surgery
6. 3-D Biocomputation 4. Osteodistraction

Teaching

2013-14 Courses


Publications

Journal Articles


  • Using bioabsorbable fixation systems in the treatment of pediatric skull deformities leads to good outcomes and low morbidity CHILDS NERVOUS SYSTEM Gephart, M. G., Woodard, J. I., Arrigo, R. T., Lorenz, H. P., Schendel, S. A., Edwards, M. S., Guzman, R. 2013; 29 (2): 297-301

    Abstract

    Bioabsorbable fixation systems have been widely employed in pediatric patients for cranial reconstruction, obviating the complications of hardware migration and imaging artifact occurring with metallic implants. Recent concern over complications unique to bioabsorbable materials, such as inflammatory reaction and incomplete resorption, necessitates additional conclusive studies to further validate their use in pediatric neurosurgery and craniofacial surgery. Likewise, long-term follow-up in this clinical cohort has not previously been described.We included consecutive pediatric patients under the age of 2, from Lucile Packard Children's Hospital, who underwent cranial vault reconstruction with the use of a bioabsorbable fixation system between 2003 and 2010. Hospital records were queried for patient characteristics, intraoperative data, and postoperative complications.Ninety-five patients with the following preoperative pathologies were analyzed: craniosynostosis (87), cloverleaf skull (5), frontonasal dysplasia (1), and frontonasal encephalocele (2). Median age was 6 months (range 1-24 months). Average case duration was 204 minutes (range 40-392 min), with median of 154 mL blood loss (range 30-500 mL). Ninety-three percent of patients had 1-4 plates implanted with 48% receiving three plates. The median number of screws used was 59 (range 0-130). The median length of hospital stay was 4 days (range 2-127 days) with an average follow-up of 22 months (five postoperative visits). The complications related to hardware implantation included swelling (1%) and broken hardware (1%), the latter of which required reoperation.The bioabsorbable fixation systems for cranial vault reconstruction in children less than 2 years of age is safe with tolerable morbidity rates.

    View details for DOI 10.1007/s00381-012-1938-y

    View details for Web of Science ID 000314028100019

    View details for PubMedID 23099613

  • Preface. Oral and maxillofacial surgery clinics of North America Schendel, S. A. 2012; 24 (4): ix-?

    View details for DOI 10.1016/j.coms.2012.09.001

    View details for PubMedID 22981079

  • Airway Growth and Development: A Computerized 3-Dimensional Analysis JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S. A., Jacobson, R., Khalessi, S. 2012; 70 (9): 2174-2183

    Abstract

    The present study was undertaken to investigate the changes in the normal upper airway during growth and development using 3-dimensional computer analysis from cone-beam computed tomography (CBCT) data to provide a normative reference.The airway size and respiratory mode are known to have a relationship to facial morphology and the development of a malocclusion. The use of CBCT, 3-dimensional imaging, and automated computer analysis in treatment planning allows the upper airway to be precisely evaluated. In the present study, we evaluated the growth of the airway using 3-dimensional analysis and CBCT data from age 6 through old age, in 1300 normal individuals.The airway size and length increase until age 20 at which time a variable period of stability occurs. Next, the airway at first decreases slowly in size and then, after age 40, more rapidly. Normative data are provided in the present study for age groups from 6 to 60 years in relation to the airway total volume, smallest cross-sectional area and vertical length of the airway.This 3-dimensional data of the upper airway will provide a normative reference as an aid in the early understanding of respiration and dentofacial anatomy, which will help in early treatment planning.

    View details for DOI 10.1016/j.joms.2011.10.013

    View details for Web of Science ID 000308319900030

    View details for PubMedID 22326177

  • Treatment of Maxillomandibular Deformities With Internal Curvilinear Distraction ANNALS OF PLASTIC SURGERY Schendel, S. A. 2011; 67 (6): S1-S9

    Abstract

    Internal curvilinear distraction is successful in achieving clinically significant distraction with stable occlusion in our patient population of infants, adolescents, and adults. When distracting the mandible, the curve of the distractor, the position of the distractor, and the osteotomy site are accountable for the final result. The curved distractor can mimic part of the natural logarithmic growth of the maxillomandibular complex. In addition, the result is predictable based on this design and the internal nature of the distractor, which can be left in place longer than other distractor types. Distraction can be combined with orthognathic surgery in certain cases resulting in increased benefit. This new procedure is called distraction orthognathics.

    View details for DOI 10.1097/SAP.0b013e3182183599

    View details for Web of Science ID 000298085900001

    View details for PubMedID 22123543

  • Image fusion in preoperative planning. Facial plastic surgery clinics of North America Schendel, S. A., Duncan, K. S., Lane, C. 2011; 19 (4): 577-?

    Abstract

    This article presents a comprehensive overview of generating a digital Patient-Specific Anatomic Reconstruction (PSAR) model of the craniofacial complex as the foundation for a more objective surgical planning platform. The technique explores fusing the patient's 3D radiograph with the corresponding high-precision 3D surface image within a biomechanical context. As taking 3D radiographs has been common practice for many years, this article describes various approaches to 3D surface imaging and the importance of achieving high-precision anatomical results to simulate surgical outcomes that can be measured and quantified. With the PSAR model readily available for facial assessment and virtual surgery, the advantages of this surgical planning technique are discussed.

    View details for DOI 10.1016/j.fsc.2011.07.002

    View details for PubMedID 22004853

  • Maxillary, Mandibular, and Chin Advancement: Treatment Planning Based on, Airway Anatomy in Obstructive Sheep Apnea JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S., Powell, N., Jacobson, R. 2011; 69 (3): 663-676

    Abstract

    Surgical correction of obstructive sleep apnea (OSA) syndrome involves understanding a number of parameters, of which the 3-dimensional airway anatomy is important. Visualization of the upper airway based on cone beam computed tomography scans and automated computer analysis is an aid in understanding normal and abnormal airway conditions and their response to surgery. The goal of surgical treatment of OSA syndrome is to enlarge the velo-oropharyngeal airway by anterior/lateral displacement of the soft tissues and musculature by maxillary, mandibular, and possibly, genioglossus advancement. Knowledge of the specific airway obstruction and characteristics based on 3-dimensional studies permits a directed surgical treatment plan that can successfully address the area or areas of airway obstruction. The end occlusal result can be improved when orthodontic treatment is combined with the surgical plan. The individual with OSA, though, is more complicated than the usual orthognathic patient, and both the medical condition and treatment length need to be judiciously managed when OSA and associated conditions are present. The perioperative management of the patient with OSA is more complex and the margin for error is reduced, and this needs to be taken into consideration and the care altered as indicated.

    View details for DOI 10.1016/j.joms.2010.11.010

    View details for Web of Science ID 000288109400010

    View details for PubMedID 21353928

  • Fronto-orbital advancement using an en bloc frontal bone craniectomy. Neurosurgery Guzman, R., Looby, J. F., Schendel, S. A., Edwards, M. S. 2011; 68 (1): 68-74

    Abstract

    Fronto-orbital advancement is a procedure commonly performed in craniofacial centers for coronal and metopic suture synostosis. Several variations of the technique have been reported.To describe our modifications to the anterior cranioplasty procedure and the results of our surgical series.Using our craniofacial database, we retrospectively analyzed the records of all patients undergoing fronto-orbital advancement for craniosynostosis. The same team of neurosurgeons and plastic surgeons performed all procedures. Demographic data, operative time, blood loss, length of stay, and clinical outcome were analyzed.Of 248 patients treated for craniosynostosis, a total of 70 patients underwent fronto-orbital advancement. Nineteen presented with metopic, 26 with unilateral coronal, 17 with bilateral coronal, and 8 with multiple synostosis. Median age at surgery was 6.5 months. Mean operative time was 210 minutes; mean blood loss was 167 mL; and length of stay was 4.5 days. A positive correlation was found between operative time and blood loss (r = 0.1, P < .01) and age at surgery and blood loss (r = 0.3, P < .0001). There was a minor morbidity rate of 2.9%. A good reconstruction was obtained in all patients using our en bloc fronto-orbital advancement without any midline osteotomies at a mean follow-up of 15 months.A team approach and the application of a standardized surgical technique should make it safer to operate in young children, shorten the surgical time, and lead to a reduction in blood loss. Reconstructing the frontal bone as an entire unit yielded excellent correction for coronal and metopic synostosis.

    View details for DOI 10.1227/NEU.0b013e31820780cd

    View details for PubMedID 21206324

  • Reliability of panoramic radiographs for the assessment of mandibular elongation after distraction osteogenesis procedures ORTHODONTICS & CRANIOFACIAL RESEARCH Hazan-Molina, H., Molina-Hazan, V., Schendel, S. A., Aizenbud, D. 2011; 14 (1): 25-32

    Abstract

    To determine whether panoramic radiographs could be used for evaluation of changes in the vertical and horizontal dimensions following internal curvilinear mandibular distraction osteogenesis.A retrospective cohort study included 25 patients who underwent bilateral mandibular distraction surgery. Three panoramic radiographs and lateral cephalograms from each patient were available: before distraction, immediately upon termination of the distraction process, and at the end of the follow-up period. The radiographs were traced by plotting Condylion, Gonion, and Menton. The linear distances between Condylion and Gonion and between Gonion and Menton were measured on each side, and the correlation was calculated.No significant differences were found between the values of the linear measurements determined by lateral cephalograms and panoramic radiographs (p ? 0.079), excluding one measurement. The correlation test for these radiographs showed very high, positive and statistically significant correlations, for both sides of the internal mandibular distraction (r > 0.77, p ? 0.0001), apart from three measurements.Panoramic radiographs, with mandibular length (Co-Go and Go-Me) measurements, can be used as an alternative to lateral cephalograms, i.e. as a reliable tool for assessing vertical and horizontal dimensional changes resulting from internal mandibular distraction achieved by a curvilinear distractor.

    View details for DOI 10.1111/j.1601-6343.2010.01504.x

    View details for Web of Science ID 000286169200003

    View details for PubMedID 21205166

  • Curvilinear Mandibular Distraction Results and Long-Term Stability Effects in a Group of 40 Patients PLASTIC AND RECONSTRUCTIVE SURGERY Aizenbud, D., Hazan-Molina, H., Thimmappa, B., Hopkins, E. M., Schendel, S. A. 2010; 125 (6): 1771-1780

    Abstract

    The mandibular internal curvilinear distractor design produces a curvilinear vector to provide ideal three-dimensional curvilinear movements compared with the limited straight unidirectional predecessor devices. In this manner, it corrects craniofacial deformities as anatomically as possible, allowing simultaneous bidirectional (rotational and translational) mandibular movement and multidirectional distraction. The aim of this study was to quantify the sagittal and vertical mandibular changes achieved through curvilinear distraction and to assess the long-term effect of this generated bone.Forty patients (20 male and 20 female), with ages ranging from 5 to 55 years, who underwent mandibular distraction from December of 1999 to August of 2007 at Lucile Packard Children's Hospital in Stanford, California, were included. Preoperatively, postoperatively, and at follow-up (at least 2 years following distraction), panoramic and lateral cephalometric radiographs were traced by plotting different skeletal landmark points and were then analyzed.All patients tolerated the curvilinear distraction process well through completion. The average of the mandibular body elongation recorded was 8 to 9 mm and 6 to 8 mm in the panoramic and cephalometric radiographs, respectively; whereas the vertical change of the mandibular ramus achieved was 10 to 12 mm and 10 to 11 mm, respectively. The curvilinear distraction effect on the mandible was found to be significantly stable when the long-term follow-up measurements were compared with the postoperative data revealed in the panoramic and lateral cephalometric radiographs for the two dimensions.The internal curvilinear device is an effective tool that achieves a stable mandibular distraction, resulting in the correction of craniofacial deformities.

    View details for DOI 10.1097/PRS.0b013e3181d9937b

    View details for Web of Science ID 000278380700026

    View details for PubMedID 20517103

  • Sagittal Split Genioplasty: A New Technique JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S. A. 2010; 68 (4): 931-934

    View details for DOI 10.1016/j.joms.2009.09.082

    View details for Web of Science ID 000276579200038

    View details for PubMedID 20307778

  • Automated 3-Dimensional Airway Analysis From Cone-Beam Computed Tomography Data JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S. A., Hatcher, D. 2010; 68 (3): 696-701

    View details for DOI 10.1016/j.joms.2009.07.040

    View details for Web of Science ID 000279280800037

    View details for PubMedID 20171491

  • CURVILINEAR DISTRACTION JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S. A. 2009; 67 (12): 2696-2697

    View details for DOI 10.1016/j.joms.2009.06.026

    View details for Web of Science ID 000272497800026

    View details for PubMedID 19925996

  • Monozygotic Twin Sister as a Template for Facial Trauma Reconstruction PLASTIC AND RECONSTRUCTIVE SURGERY Aizenbud, D., Morrill, L. R., Schendel, S. A. 2009; 124 (6): 443E-445E

    View details for DOI 10.1097/PRS.0b013e3181bcf535

    View details for Web of Science ID 000272615600076

    View details for PubMedID 19952610

  • Three-Dimensional Imaging and Computer Simulation For Office-Based Surgery JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S. A., Jacobson, R. 2009; 67 (10): 2107-2114

    Abstract

    Advancements in computers and imaging, especially over the last 10 years, have permitted the adoption of 3-dimensional imaging protocols in the health care field. In addition, the affordability and ease of use of these modalities allow their widespread adoption and use in diagnosis and treatment planning. This is particularly important when the deformities are complex involving both function and esthetics, such as those in the dentofacial area and with orthognathic surgery.Image fusion involves combining images from different imaging modalities to create a virtual record of an individual called a patient-specific anatomic reconstruction (PSAR). We describe the system and show its use in 1 case.Image fusion and, more specifically, PSAR permit a more accurate analysis of deformity as an aid to diagnosis and treatment planning.Three-dimensional imaging and computer simulation can be effectively used for planning office-based procedures. The PSAR can be used to perform virtual surgery and establish a definitive and objective treatment plan for correction of a facial deformity. The end result is improved patient care and decreased expense.

    View details for DOI 10.1016/j.joms.2009.04.111

    View details for Web of Science ID 000270520900009

    View details for PubMedID 19761904

  • Airway Analysis: With Bilateral Distraction of the Infant Mandible JOURNAL OF CRANIOFACIAL SURGERY Looby, J. F., Schendel, S. A., Lorenz, H. P., Hopkins, E. M., Aizenbud, D. 2009; 20 (5): 1341-1346

    Abstract

    Mandibular distraction was proven to be a valuable tool for lengthening the hypoplastic mandible and relieving airway obstruction in infants. However, analysis of presurgical and postsurgical three-dimensional computed tomography and polysomnogram studies is lacking. The aim of this study was to describe the effect of distraction on the airway by evaluating the clinical, three-dimensional radiographic and polysomnogram studies before and after distraction.Seventeen infants with micrognathia who underwent internal curvilinear mandibular distraction from April 2005 through April 2008 at Lucile Packard Children's Hospital were included. Preoperative and postoperative computed tomography, polysomnograms, and feeding evaluations were obtained and compared after distraction.The mean patient age before surgery was 105 days. All patients tolerated the distraction process with a mean mandibular advancement of 18.1 mm. One patient experienced a temporary marginal mandibular nerve palsy that resolved, and 1 postoperative wound infection was encountered. Preoperatively, the mean retroglossal oropharyngeal cross-sectional area was 41.53 mm. This was associated with a mean preoperative apnea-hypopnea index (AHI) of 10.57 and a minimum oxygen desaturation of 83%. After distraction, the mean airway increased to 127.77 mm. All patients had clinical improvement of their respiratory status; the mean postoperative AHI was 2.21, and the minimum oxygen desaturation was 90%. The result was a 209% cross-sectional airway increase. All patients progressed to oral feeds by 3.5 months postoperatively.Mandibular distraction is effective at relieving anatomic airway obstruction in infants with micrognathia and obstructive sleep apnea while avoiding some previously reported associated complications.

    View details for DOI 10.1097/SCS.0b013e3181ae4139

    View details for Web of Science ID 000270369000008

    View details for PubMedID 19816252

  • Magnesium-Based Bone Cement and Bone Void Filler: Preliminary Experimental Studies JOURNAL OF CRANIOFACIAL SURGERY Schendel, S. A., Peauroi, J. 2009; 20 (2): 461-464

    Abstract

    Bone cement has great potential in craniofacial surgery in the repair of osseous defects secondary to surgery or trauma. This includes the use of bone cement as a bone void filler for full-thickness cranial defects and as augmentation of deficient bones. Ideally, this material should be easily available, biocompatible, resorbable, bone inductive, and have adhesive qualities to bone. Calcium-based bone cements have some of these qualities but have a higher than desirable failure rate. OsteoCrete, a new magnesium-based bone cement and bone void filler, was compared to Norian in critical-sized skull defects and cementing bone flaps in rabbits. Both materials were successful; however, OsteoCrete had a faster resorption and replacement by bone rate than Norian. Bone flap position and apparent stability were also superior with OsteoCrete. There were no adverse reactions to either cement. A magnesium-based bone cement presents with advantages when compared with a comparator calcium-based cement in craniofacial surgery.

    View details for DOI 10.1097/SCS.0b013e31819b9819

    View details for Web of Science ID 000264570300042

    View details for PubMedID 19305245

  • A Web-Based, Integrated Simulation System for Craniofacial Surgical Planning PLASTIC AND RECONSTRUCTIVE SURGERY Schendel, S. A., Montgomery, K. 2009; 123 (3): 1099-1106

    Abstract

    Advances in computing over the last 10 years have rapidly improved imaging and simulation in health care. Implementation of three-dimensional protocols and image fusion techniques are moving diagnosis, treatment planning, and teaching to a next-generation paradigm. In addition, decreasing cost and increasing availability make generalized use of these techniques possible.In this article, the authors present a Web-based, integrated simulation system for craniofacial surgical planning and treatment. Image fusion technology was utilized to create a realistic virtual image that can be manipulated in real time. The resultant data can then be shared over the Internet by distantly located practitioners.Initial use of this system proved to be beneficial from a planning standpoint and to be accurate as to the reliability of landmark identification. Additional case studies are needed to further document the results of actual surgical simulation.This technology presents significant advantages in surgical planning and education, both of which can improve patient safety and outcomes.

    View details for DOI 10.1097/PRS.0b013e318199f653

    View details for Web of Science ID 000264017900042

    View details for PubMedID 19319079

  • Internal maxillary distraction with a new bimalar device JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Kahn, D. M., Broujerdi, J., Schendel, S. A. 2008; 66 (4): 675-683

    Abstract

    Distraction osteogenesis of the Le Fort I segment is advocated for patients who require significant advancement of the maxilla or who have a soft tissue envelope compromised by scar tissue. We present a technique for maxillary distraction using an interconnecting intraoral device anchored to the malar prominences above the osteotomy and either the maxilla and/or the dentition below the level of the osteotomy.Ten patients with nonsyndromic cleft lip and palate, mean age of 18, underwent Le Fort I maxillary distraction osteogenesis for management of maxillary hypoplasia. A Le Fort I osteotomy is performed and a Spectrum Intraoral Midface Multi-Vector Distractor (OsteoMed, Addison, TX) is placed leaving a 1 mm to 2 mm distraction gap. After a 2 to 4 day latency period, distraction begins at a rate of 1 mm a day. Once the desired occlusion is achieved the device is left in place for a minimum of 2 months for consolidation.Preoperative Sella-Nasion-A point measurements from lateral cephalograms averaged 74 degrees (range, 70-76 degrees). Postoperative Sella-Nasion-A point averaged 81 degrees (range, 75-89 degrees). Preoperative overjet averaged -7.4 mm (range, -3 to -13 mm). Postoperative overjet averaged 2.6 mm (range, 1-3 mm). Average distraction was 9 mm (range, 6-16 mm). The average vertical movement was 7.2 mm in an inferior direction (range, 0-15 mm). The results remained stable at a follow-up of 30 months.We report on distraction of the Le Fort I segment using an internal device. The device design allows the forces of distraction to be shared across a larger surface area delivering a uniform and reliable vector of distraction with increased stability.

    View details for DOI 10.1016/j.joms.2007.09.006

    View details for Web of Science ID 000254589200009

    View details for PubMedID 18355590

  • Computer simulation of curvilinear mandibular distraction: Accuracy and predictability PLASTIC AND RECONSTRUCTIVE SURGERY Scolozzi, P., Link, D. W., Schendel, S. A. 2007; 120 (7): 1975-1980

    Abstract

    The purpose of this study was to retrospectively evaluate the accuracy and reliability of a computer simulation system that predicts the results of an internal curvilinear mandibular distractor in the treatment of hemifacial microsomia and severe mandibular retrognathia.A two-dimensional computer analysis and simulation system was developed based on cephalometric radiographs and patient photographs. The software was used to generate and superimpose digital templates, corresponding to the actual distractor and logarithmic spiral, onto the lateral cephalometric tracings. The digital distractor's template was then adjusted to fit the radiographic projection of the actual distractor on the 1-week postoperative lateral cephalograph as precisely as possible. It was then activated along the spiral growth curve template until the ideal position of the mandible was reached. This computational surgical simulation tracing was then superimposed onto the actual postdistraction lateral cephalometric radiograph and tracing. Thus, the predicted and actual mandibular distraction movements were compared.In all of the cases, the computational distraction (skeletal and soft tissues) tracing fit the actual postdistraction tracing with an accuracy to within 1 mm.The current study demonstrated that a specific curvilinear distraction can (1) closely reproduce the natural logarithmic spiral movement of the mandibular growth, (2) be closely approximated and thus predicted by a computer simulation system, and (3) be used for correction of mandibular deformities such as hemifacial microsomia and severe mandibular retrognathia.

    View details for DOI 10.1097/01.prs.0000287327.66824.2f

    View details for Web of Science ID 000251668400028

    View details for PubMedID 18090762

  • Infant mandibular distraction with an internal curvilinear device JOURNAL OF CRANIOFACIAL SURGERY Miller, J. J., Kahn, D., Lorenz, H. P., Schendel, S. A. 2007; 18 (6): 1403-1407

    Abstract

    Mandibular distraction has proven to be a valuable tool for lengthening the hypoplastic mandible and relieving airway obstruction in infants. Numerous devices have been developed to achieve the desired mandibular lengthening. Complications including poor vector control, need to mold regenerate, facial scarring, external pin loosening, and bulky hardware have been associated with previous devices. In an attempt to circumvent some of these problems, the senior author developed an internal curvilinear device (Osteomed Corporation, Dallas, TX), which is applicable to the infant mandible. The aim of this paper is to describe the use of this distractor as well as its indications and outcomes.Twelve micrognathic infants (ages range from 9 days to 8 months) who underwent mandibular distraction between March 2005-May 2006 at Lucile Packard Children's Hospital were included in the study. Preoperative workup included an evaluation by a multidisciplinary team including a pediatric otolaryngologist, neonatal intensivist, pediatric pulmonologist, occupational therapist, and craniofacial surgeon. Pre and postoperative maxillomandibular discrepancy, sleep study, feeding evaluation, and three-dimensional computerized tomography scans were compared. All patients tolerated the distraction process well to completion without postoperative complication, except for one patient who had temporary facial nerve weakness, which resolved in 2 months. All patients with obstructive apnea had the obstructive component improved. The last six patients had pre and postoperative polysomnograms to document the improvement. Two patients with neurologic impairment had persistent central apnea. One nonsyndromic patient with inability to feed and feeding-related airway obstruction was taking complete oral feeds 2 weeks after distraction.Mandibular distraction with an internal curvilinear device is effective at relieving airway obstruction in micrognathic infants, while avoiding some previously reported complications.

    View details for Web of Science ID 000251517500026

    View details for PubMedID 17993889

  • Idiopathic condylar resorption and micrognathia: The case for distraction osteogenesis JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Schendel, S. A., Tulasne, J., Linck, D. W. 2007; 65 (8): 1610-1616

    View details for DOI 10.1016/j.joms.2007.05.001

    View details for Web of Science ID 000248706000027

    View details for PubMedID 17656291

  • Surgical orthognathic management of sleep apnea JOURNAL OF CRANIOFACIAL SURGERY Schendel, S. A., Powell, N. B. 2007; 18 (4): 902-911

    Abstract

    Management of obstructive sleep apnea syndrome (OSAS) requires a clear understanding of both the medical and surgical components of the treatment and interpretation of the subjective and objective data such as the polysomnagram. Medical management is primarily by continuous positive airway pressure (CPAP) and is the first line of treatment. Surgical management consists of several phases based on the severity and location of the anatomical abnormalities. The last phase of surgical management consists of maxillo-mandibular advancement by a Le Fort I osteotomy and bilateral sagittal split ramus osteotomies of the mandible. The orthognathic procedure is based on the existing skeletal deformity, occlusion and severity of the OSAS. The surgical technique must also take into consideration not only the usual orthognathic principles but the added medical complexity of these patients in the immediate pre and post operative periods.

    View details for Web of Science ID 000248513100034

    View details for PubMedID 17667685

  • Flash Pulmonary Edema: An Unusual Presentation during Orthognathic Surgery PLASTIC AND RECONSTRUCTIVE SURGERY Broujerdi, J. A., Keifa, E., Nekhendzy, V., Schendel, S. A. 2007; 119 (6): 133E-137E
  • Invited discussion: Surgical treatment of Treacher Collins syndrome ANNALS OF PLASTIC SURGERY Miller, J. J., Schendel, S. A. 2006; 56 (5): 555-556
  • A surgical simulator for planning and performing repair of cleft lips JOURNAL OF CRANIO-MAXILLOFACIAL SURGERY Schendel, S., Montgomery, K., Sorokin, A., Lionetti, G. 2005; 33 (4): 223-228

    Abstract

    The objective of this project was to develop a computer-based surgical simulation system for planning and performing cleft lip repair. This system allows the user to interact with a virtual patient to perform the traditional steps of cleft-lip repair (rotation-advancement technique).The system interfaces to force-feedback (haptic) devices to track the user's motion and provide feedback during the procedure, while performing real-time soft-tissue simulation. An 11-day-old unilateral cleft lip, alveolus and palate patient was previously CT scanned for ancillary diagnostic purposes using standard imaging protocols and 1mm slices. High-resolution 3D meshes were automatically generated from this data using the ROVE software developed in-house. The resulting 3D meshes of bone and soft tissue were instilled with physical properties of soft tissues for purposes of simulation. Once these preprocessing steps were completed, the patient's bone and soft tissue data are presented on the computer screen in stereo and the user can freely view, rotate, and otherwise interact with the patient's data in real time. The user is prompted to select anatomical landmarks on the patient's data for preoperative planning purposes, then their locations are compared against that of a 'gold standard' and a score, derived from their deviation from that standard and time required, is generated. The user can then move a haptic stylus and guide the motion of the virtual cutting tool. The soft tissues can thus be incised using this virtual cutting tool, moved using virtual forceps, and fused in order to perform any of the major procedures for cleft lip repair. Real-time soft tissue deformation of the mesh realistically simulates normal tissues and haptic-rate (>1 kHz) force-feedback is provided. The surgical result of the procedure can then be immediately visualized and the entire training process can be repeated at will. A short evaluation study was also performed. Two groups (non-medical and plastic surgery residents) of six persons each performed the anatomical marking task of the simulator four times.Results showed that the plastic surgery residents scored consistently better than the persons without medical background. Every person's score increased with practice, and the length of time needed to complete the 11 markings decreased. The data was compiled and showed which specific markers consistently took users the longest to identify as well as which locations were hardest to accurately mark.These findings suggest that the simulator is a valuable training tool, giving residents a way to practice anatomical identification for cleft lip surgery without the risks associated with training on a live patient. Educators can also use the simulator to examine which markers are consistently problematic, and modify their training to address these needs.

    View details for DOI 10.1016/j.jcms.2005.05.002

    View details for Web of Science ID 000230975800001

    View details for PubMedID 15975810

  • User interface paradigms for patient-specific surgical planning: lessons learned over a decade of research COMPUTERIZED MEDICAL IMAGING AND GRAPHICS Montgomery, K., Stephanides, M., Schendel, S., Ross, M. 2005; 29 (2-3): 203-222

    Abstract

    This paper covers work in virtual reality-based, patient-specific surgical planning over the past decade. It aims to comprehensively examine the user interface paradigms and system designs during that period of time and to objectively analyze their effectiveness for the task. The goal is to provide useful feedback on these interface and implementation paradigms to aid other researchers in this field. First, specialized systems for specific clinical use were produced with a limited set of visualization tools. Later, through collaboration with NASA, an immersive virtual environment was created to produce high-fidelity images for surgical simulation, but it underestimated the importance of collaboration. The next system, a networked, distributed virtual environment, provided immersion and collaboration, but the immersive paradigm was found to be of a disadvantage and the uniqueness of the framework unwieldy. A virtual model, workbench-style display was then created using a commercial package, but limitations of each were soon apparent. Finally, a specialized display, with an integrated visualization and simulation system is described and evaluated. Lessons learned include: surgical planning is an abstract process unlike surgical simulation; collaboration is important, as is stereo visualization; and that high-resolution preoperative images from standard viewpoints are desirable, but interaction is truly the key to planning.

    View details for DOI 10.1016/j.compmedimag.2004.09.014

    View details for Web of Science ID 000227961600011

    View details for PubMedID 15755538

  • Magnetic resonance imaging and surgical repair of cleft palate in a four-week-old canine (Canis familiaris): An animal model for cleft palate repair CONTEMPORARY TOPICS IN LABORATORY ANIMAL SCIENCE Tolwani, R. J., Hagan, C. E., Runstadler, J. A., Lyons, H., Green, V. L., Bouley, D. M., Rodriguez, L. F., Schendel, S. A., Moseley, M. E., Daunt, D. A., Otto, G., CORK, L. C. 2004; 43 (6): 17-21

    Abstract

    Successful cleft palate repair (palatoplasty) was accomplished in a male canine pup from a kindred with autosomal recessive transmission for a complete cleft palate phenotype. This case represents the potential application of a new animal model for cleft palate repair. This reproducible congenital defect provides a clinically relevant model to improve research into the human anomaly, as compared with previous iatrogenic or teratogenically induced animal models. This case report presents the basis for new repair techniques and for studying the genetic basis of the cleft palate defect.

    View details for Web of Science ID 000225806200004

    View details for PubMedID 15636550

  • Mandibular distraction osteogenesis by sagittal split osteotomy and intraoral curvilinear distraction JOURNAL OF CRANIOFACIAL SURGERY Schendel, S. A., Linck, D. W. 2004; 15 (4): 631-635

    Abstract

    Mandibular distraction combining the sagittal split ramus osteotomy and an intraoral curved distractor is efficacious to lengthen the mandibular body and ramus. The sagittal split permits immediate rotation of the proximal segment and lengthening while still providing a large surface interface for regenerative bone. The buried curved distractor enables mandibular lengthening along the normal logarithmic grow spiral as shown by Moss and Rickets. In addition, it is well tolerated by the patient and can remain in place for a long duration to provide support. In summary, this combination of surgical techniques provides certain advantages for distraction of the mandible.

    View details for Web of Science ID 000222503200019

    View details for PubMedID 15213543

  • A surgical simulator for cleft lip planning and repair MEDICINE MEETS VIRTUAL REALITY 11 Montgomery, K., Sorokin, A., Lionetti, G., Schendel, S. 2003; 94: 204-209

    Abstract

    The objective of this project was to develop a computer-based surgical simulation system for cleft lip planning and repair. This system allows the user to interact with a virtual patient to perform the traditional steps of cleft-lip repair. The system interfaces to force-feedback (haptic) devices to track the user's motion and provide feedback during the procedure, while performing real-time soft-tissue simulation. An eleven-day old unilateral cleft-lip and palate patient was previously CT scanned for ancillary diagnostic purposes using standard imaging protocols and 1mm slices. High-resolution 3D meshes were automatically generated from this data using the ROVE software created in our lab. The resulting 3D meshes of bone and soft-tissue were instilled with physical properties of soft tissues for purposes of simulation. Once these preprocessing steps were completed, the patient's bone and soft-tissue data are presented on the computer screen in stereo and the user can freely view, rotate, and otherwise interact with the patient's data in real-time. The user is prompted to select anatomical landmarks on the patient data for preoperative planning purposes, then their locations are compared against that of a "gold standard" and a score, derived from their deviation from that standard and time required, is generated. The user can then move a haptic stylus and guide the motion of the virtual cutting tool. The soft tissues can thus be incised using this virtual cutting tool, moved using virtual forceps, and fused in order to perform any of the major procedures for cleft-lip repair. Real-time soft tissue deformation of the mesh realistically simulates normal tissues and haptic-rate (>1kHz) force-feedback is provided. The surgical result of the procedure can then be immediately visualized and the entire training process can be repeated at will. A short evaluation study was also performed. Two groups (nonmedical and plastic surgery residents) of six-people each performed the anatomical marking task of the simulator four times. Results showed that the plastic surgery residents scored consistently better than the people without medical background. Every person's score increased with practice, and the length of time needed to complete the eleven markings decreased. The data was compiled and showed which specific markers consistently took users the longest to identify as well as which locations were hardest to accurately mark. Our findings suggest that the simulator is a valuable training tool, giving residents a way to practice anatomical identification for cleft lip surgery without the risks associated with training on a live patient. Educators can also use the simulator to examine which markers are consistently problematic, and modify their training to address these needs.

    View details for Web of Science ID 000189484800042

    View details for PubMedID 15455894

  • Unilateral cleft lip repair - State of the art CLEFT PALATE-CRANIOFACIAL JOURNAL Schendel, S. A. 2000; 37 (4): 335-341

    Abstract

    A number of surgical techniques are utilized to correct the unilateral cleft lip, including variations of the rotation-advancement technique. This attests to the variability of the original deformity and the esthetic and functional results from any one technique, especially those based on traditional geometric rearrangement of the skin and associated tissues.Most recent advances in cleft lip repair have occurred in two main areas. The morphological result has been improved by functional muscular reconstruction of the lip with or without orthopedic molding. Early correction of the nasal deformity has also been readvocated based on newer principles with excellent results demonstrated.Further work continues in these areas and improved outcomes will continue to be seen along with a clearer understanding of surgical affects on growth and development.

    View details for Web of Science ID 000088074300001

    View details for PubMedID 10912710

  • Development and application of a virtual environment for reconstructive surgery. Computer aided surgery Montgomery, K., Stephanides, M., Schendel, S. 2000; 5 (2): 90-97

    Abstract

    This paper details the development and application of a Virtual Environment for Reconstructive Surgery (VERS). It addresses the technical and user-interface challenges in developing such a system, and the lessons learned during application of the system in the case of a 17-year-old boy with a severe facial defect arising from the removal of a soft-tissue sarcoma.Computed tomography (CT) scans were segmented into bone and soft-tissue classifications using traditional and novel algorithms, a surface mesh was generated, and imaging artifacts were removed, yielding a mesh suitable for visualization. This patient-specific mesh was then used in a virtual environment by the surgeons for preoperative visualization of the defect, planning of the surgery, and production of a custom surgical template to aid in repairing the defect.This system was successfully used to plan the surgery of the patient and to produce a custom, patient-specific template that was used to harvest bone from a donor site in order to reconstruct the defect.Despite technical challenges, virtual-environment surgical planning is useful as a clinical tool for preoperative visualization, cephalometric analysis, and surgical intervention. It can provide a more precise surgical result than would otherwise be realized using traditional methods.

    View details for PubMedID 10862131

  • Adverse outcomes in orthognathic surgery and management of residual problems CLINICS IN PLASTIC SURGERY Schendel, S. A., Mason, M. E. 1997; 24 (3): 489-?

    Abstract

    Adverse outcomes in orthognathic surgery include both functional and aesthetic components that frequently coexist. Reasons for this occurrence are multifactorial and can be classified in broad categories of diagnosis, treatment planning, technical execution, and unpreventable outcomes. Management of the residual deformities is both functional and aesthetic as based on correctly delineating the problem and its cause.

    View details for Web of Science ID A1997XL79900007

    View details for PubMedID 9246515

  • Preliminary report: A ceramic containing crosslinked collagen as a new cranial onlay and inlay material ANNALS OF PLASTIC SURGERY Schendel, S., Bresnick, S., CHOLON, A. 1997; 38 (2): 158-162

    Abstract

    Simple ceramic bone graft materials have demonstrated significant limitations for use in craniomaxillary reconstruction. We investigated a new, alloplastic composite bone grafting material containing particulate hydroxyapatite and crosslinked collagen in a time-sequence study. Five rabbits underwent surgical placement of high-loading and low-loading composite onlay and inlay grafts in the parietal region of the skull. Animals were sacrificed at either 1, 2, 4, or 6 months postoperatively. All rabbits demonstrated tissue continuity and healing of both onlay and inlay grafts to the outer table of the skull. Bony ingrowth was shown in both onlays and inlays with bone proliferation and vascularization. Bony ingrowth was seen as early as 1 month postoperatively. Inlay grafts healed flush to the outer table, while onlay grafts maintained at least 80% of graft volume at 6 months postoperatively. We conclude that a composite bone grafting material containing a ceramic and collagenous matrix may offer significant advantages to the reconstructive surgeon. The material appears to be easy to handle and carve, is biologically tolerated, and is able to maintain graft volume. Further studies of this new composite material are warranted.

    View details for Web of Science ID A1997WH42100011

    View details for PubMedID 9043585

  • A mathematical model for mandibular distraction osteogenesis JOURNAL OF CRANIOFACIAL SURGERY Schendel, S. A., Heegaard, J. H. 1996; 7 (6): 465-468

    Abstract

    In this paper, we look at the mechanobiological processes involved in mandibular distraction and, as a first approximation, propose an elastoplastic uniaxial model.

    View details for Web of Science ID A1996VU66100013

    View details for PubMedID 10332267

  • Treatment of periorbital edema with human corticotropin-releasing factor after blepharoplasty JOURNAL OF THE AMERICAN COLLEGE OF SURGEONS Schendel, S. A., Stephanides, M. 1996; 182 (3): 226-232

    Abstract

    This prospective study of 32 patients was undertaken to ev evaluate the formation of postoperative periorbital edema after administration of human corticotropin-releasing factor (hCRF). Human corticotropin-releasing factor has strong antiedematous properties as a result of direct action on blood vessels independent of endocrine function and has been shown to have a positive effect on vascular permeability in animal studies independent of corticosteroid effects.Human corticotropin-releasing factor was administered intravenously preoperatively to patients undergoing blepharoplasty in doses of 2, 4, and 8 mu g/kg body weight as a randomized, double-blind, placebo-controlled study. The periorbital edema was measured by the use of a three-dimensional laser scanner to determine facial and eyelid volume changes as specified times postoperatively.Human corticotropin-releasing factor was well tolerated when administered intravenously over a ten-minute period to healthy patients undergoing blepharoplasty. Mild transitory flushing and hypotension were the most common adverse events. Transient decreases in systolic and diastolic blood pressure and increases in heart rate occurred at hCRF doses greater than 2 mu g/kg and were most prominent at 8 mu g/kg. The 8 mu g/kg hCRF dose also showed a trend toward less postoperative edema but this was not statistically significant at the p<0.05 level.Human corticotropin-releasing factor appears to be safe for intravenous use in patients undergoing blepharoplasty; however, its efficacy in reducing postoperative edema as a single preoperative administration was not conclusively demonstrated in this study. Further research with a larger study population and other dosing regimens is indicated.

    View details for Web of Science ID A1996TY53800006

    View details for PubMedID 8603242

  • CORRECTION OF SCAPHOCEPHALY SECONDARY TO VENTRICULAR SHUNTING PROCEDURES PLASTIC AND RECONSTRUCTIVE SURGERY SHUSTER, B. A., Norbash, A. M., Schendel, S. A. 1995; 96 (5): 1012-1019

    Abstract

    Craniosynostosis following ventricular shunting procedures for hydrocephalus has become a recognized complication of shunting procedures. Secondary synostosis results from a decrease in intracranial volume leading to collapse of the cranial vault. Since this represents a distinct etiopathogenesis different from that typically involved, the surgical approach should be altered. Eight patients with secondary scaphocephaly underwent surgical reconstruction. The clinical data and radiographic studies were reviewed for these patients. The surgical approach consisted of sagittal or parasagittal strip craniectomies, lateral osteotomies with bone-flap expansion, occipital and frontal remodeling as needed, and the application of rigid fixation to maintain contour and prevent recurrent collapse of the cranial vault. Patient follow-up ranged from 3 to 37 months. Five of these patients were premature infants, an association not previously recognized in the literature. Satisfactory results were obtained in all patients. Keeping the craniectomy sites parent and achieving a more normal cranial contour through cranial remodeling have provided good results in this population.

    View details for Web of Science ID A1995RX59300002

    View details for PubMedID 7568474

  • EXPANDING CRANIAL DEFECTS FOLLOWING CRANIOFACIAL SURGERY PLASTIC AND RECONSTRUCTIVE SURGERY UMANSKY, W., Schendel, S. A. 1995; 96 (4): 969-971

    Abstract

    Growing skull fractures or posttraumatic leptomeningeal cysts are a known complication of skull fractures sustained in infancy and childhood. They usually present as progressively enlarging cranial masses at the site of the linear skull fractures. The pathogenesis is believed to require an underlying dural tear that allows herniation of the growing pulsatile brain and leads to resorption of the overlying bone. Similar enlarging cranial masses have been reported following craniofacial surgery. Our case occurred following reconstruction of a stenosed metopic suture. The treatment of this unusual complication of craniofacial surgery requires sound dural repair. An understanding of the similarity between this complication and the more common growing skull fractures of childhood is essential to a sound approach to diagnosis and treatment.

    View details for Web of Science ID A1995RT10300032

    View details for PubMedID 7652074

  • TREATMENT OF THE CRANIOFACIAL COMPLICATIONS OF BECKWITH-WIEDEMANN SYNDROME PLASTIC AND RECONSTRUCTIVE SURGERY Menard, R. M., Delaire, J., Schendel, S. A. 1995; 96 (1): 27-33

    Abstract

    Variable degrees of macroglossia have been noted in patients with Beckwith-Wiedemann syndrome. Past studies have shown that a major effect of the macroglossia is protrusion of dentoalveolar structures, resulting in an anterior open bite and a prognathic mandibular appearance secondary to an abnormally obtuse gonial angle and increased effective mandibular length. In our series of 11 Beckwith-Wiedemann syndrome patients we have observed that early correction of the macroglossia by means of partial glossectomy has resulted in decreased anterior open bite and mandibular prognathism as compared with patients managed conservatively.

    View details for Web of Science ID A1995RG78800004

    View details for PubMedID 7604127

  • CROUZONS-DISEASE CORRELATES WITH LOW FIBROBLASTIC GROWTH-FACTOR RECEPTOR ACTIVITY IN STENOSED CRANIAL SUTURES JOURNAL OF CRANIOFACIAL SURGERY Bresnick, S., Schendel, S. 1995; 6 (3): 245-248

    Abstract

    Reports have demonstrated that Crouzon's disease is associated with a gene on chromosome 10 coding for the fibroblastic growth factor (FGF) receptor 2. The purpose of this investigation was to evaluate the FGF receptor 2 levels in cranial sutures of children with Crouzon's disease and nonsyndromic, isolated craniosynostosis. Twelve children between the ages of 6 and 24 months were studied. Four patients had Crouzon's disease with coronal suture stenosis. The 8 remaining had a nonsyndromic, isolated coronal stenosis. Stenosed and adjacent nonstenosed cranial sutures were removed at cranioplasty and promptly fixed, decalcified, and embedded in paraffin. Immunohistochemical analysis of cranial sutures was performed with labeled, specific anti-FGF receptor 2 antibodies. In children with Crouzon's disease, we found significantly lower levels of FGF receptor 2 staining in stenosed sutures compared with nonstenosed sutures. In addition, sutures from children with Crouzon's disease demonstrated lower levels of FGF receptor 2 activity in both stenosed and nonstenosed sutures compared with children with a nonsyndromic, isolated coronal stenosis. However, there were no significant differences in FGF receptor 2 staining between stenosed and nonstenosed sutures in children with a nonsyndromic, isolated coronal stenosis. These findings suggest that low FGF receptor 2 activity in cranial sutures correlates with Crouzon's disease. This work supports genetic studies and yet shows that patients with Crouzon's disease have low FGF receptor 2 activity in cranial sutures. The findings also suggest that there may be etiological differences between syndrome- and nonsyndrome-associated craniosynostoses in children.

    View details for Web of Science ID A1995QY84700011

    View details for PubMedID 9020696

  • HISTOCHEMICAL ANALYSIS OF CLEFT-PALATE MUSCLE PLASTIC AND RECONSTRUCTIVE SURGERY Schendel, S. A., CHOLON, A., Delaire, J. 1994; 94 (7): 919-923

    Abstract

    Research has clarified the abnormal insertions and orientations of the involved musculature in cleft palate. However, little is known about the physiologic aspects of these muscles, specifically from a histochemical perspective. In this study, 30 muscle specimens were removed from the palatal cleft margin in patients undergoing primary palatoplasty. Nine patients had combined cleft lip and palate deformity, and seven had an isolated cleft palate. Biopsies were taken from the area of the musculus uvulus in all specimens and examined by histochemical techniques. The percentage of type 1 and type 2 fibers was different in isolated cleft palate as compared with cleft lip and palate specimens, being, respectively, 56.7 percent type 1 and 43.3 percent type 2 and 62.0 percent type 1 and 38.0 percent type 2 fibers. This is the opposite ratio from other facial muscles but is in line with the literature regarding normal palatal muscle. Isolated cleft palate muscle fibers also were minimally decreased in diameter as compared with normal facial muscle. Fiber diameters of the combined cleft lip and palate muscles were severely decreased in size compared with those muscles found in the cleft lip. Abnormal mitochondrial accumulations also were found in cleft lip and palate muscle specimens but not in isolated cleft palate muscle specimens. We consider the decrease in muscle diameter found in isolated cleft palate to be secondary to functional atrophy, while that in the cleft lip and palate specimens is secondary to a primary hypoplasia together with a functional atrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1994PV33900003

    View details for PubMedID 7972479

  • MULTIPLE-SUTURE SYNOSTOSIS SUBSEQUENT TO VENTRICULAR SHUNTING PLASTIC AND RECONSTRUCTIVE SURGERY Schendel, S. A., Shuer, L. M. 1994; 93 (5): 1073-1077

    View details for Web of Science ID A1994ND65800028

    View details for PubMedID 8134467

  • THE ASSOCIATION OF CLEFT-LIP AND PALATE WITH AICARDI SYNDROME PLASTIC AND RECONSTRUCTIVE SURGERY UMANSKY, W. S., Neidich, J. A., Schendel, S. A. 1994; 93 (3): 595-597

    Abstract

    In summary, Aicardi syndrome is defined by its tetrad of infantile spasms, agenesis of the corpus callosum, mental retardation, and chorioretinal lacunae. We report a case of Aicardi syndrome with associated cleft lip and palate. This is an infrequent finding that is present in approximately 3 percent of reported cases. Plastic surgeons should be aware of this association when treating patients with cleft lip and palate.

    View details for Web of Science ID A1994MZ50600026

    View details for PubMedID 8115518

  • AN ANALYSIS OF LE-FORT-I MAXILLARY ADVANCEMENT IN CLEFT-LIP AND PALATE PATIENTS PLASTIC AND RECONSTRUCTIVE SURGERY ESKENAZI, L. B., Schendel, S. A. 1992; 90 (5): 779-787

    Abstract

    We present a series of 24 consecutive cleft lip and palate patients aged 16 to 46 years (mean age 27 years) who underwent Le Fort I maxillary advancement by the senior author over the past 8 years. Two groups, one of 12 patients with wire fixation and one of 12 patients with miniplate fixation, were evaluated. Each group had 10 unilateral and 2 bilateral clefts. All patients were grafted with autogenous bone (8 cranial, 14 iliac, and 2 mandibular). Horizontal advancement was 3 mm to 2 cm (with a mean of 7.8 mm). Vertical movement ranged from a shortening of 5 mm to a lengthening of 1.3 cm (mean 2.3 mm of lengthening). The amount and timing of relapse were compared in both the horizontal and vertical dimensions. The plated group was more stable in both the horizontal and vertical dimensions (p < 0.05). No significant skeletal relapses occurred after the first year. Statistically significant dental relapse occurred only in the wired group. Three patients developed transverse collapse of the small maxillary cleft segment, and four developed incisor angulation to compensate for maxillary skeletal relapse. The presence of a pharyngeal flap at the time of advancement appeared to increase relapse in both horizontal and vertical dimensions (p < 0.03), but there were too few patients (7 of 24) with pharyngeal flaps to prove this conclusively. We also concluded that pterygomandibular grafting is not necessary to achieve excellent results using miniplate fixation; autogenous grafting of the anterior maxillary osteotomy alone provides the necessary stability.

    View details for Web of Science ID A1992JW18000007

    View details for PubMedID 1410030

  • NASAL CONSIDERATIONS IN ORTHOGNATHIC SURGERY AMERICAN JOURNAL OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS Schendel, S. A., Carlotti, A. E. 1991; 100 (3): 197-208

    Abstract

    The functional correction of dentofacial deformities by orthognathic surgery produces major changes in facial appearance. Facial esthetics must therefore be equally appreciated by the orthodontist and the maxillofacial surgeon. The orthodontist must perform a thorough esthetic facial evaluation along with his usual orthodontic evaluation. The treatment plan must then be based on the esthetic evaluation and knowledge of the facial changes caused by orthodontic treatment and skeletal jaw surgery. Central to facial form is the nose. This article will outline the proper functional and esthetic evaluation of the nose in relation to the face. Nasal and upper lip changes associated with maxillary procedures will also be covered in detail. In light of these two areas, proper treatment planning and sequencing will be discussed.

    View details for Web of Science ID A1991GE85500003

    View details for PubMedID 1877544

  • PATHOPHYSIOLOGY OF CLEFT-LIP MUSCLES FOLLOWING THE INITIAL SURGICAL REPAIR PLASTIC AND RECONSTRUCTIVE SURGERY Schendel, S. A., Pearl, R. M., DeArmond, S. J. 1991; 88 (2): 197-200

    Abstract

    Muscle biopsy specimens taken from the upper lip and perialar area during the time of secondary lip revision and studied by histochemical techniques demonstrate persistent connective-tissue and muscle abnormalities even at a distance from the cleft margins. Some of these changes are consistent with surgically induced denervation-reinnervation of muscle groups in the surgical field. Increased amounts of connective tissue also were found, most likely secondary to the original deformity and the subsequent surgical procedures. Both these changes may be important factors in subsequent abnormal growth and development of the underlying midfacial structures. This study also demonstrated the resolution of previously noted mitochondrial abnormalities found in the primary cleft lip patient.

    View details for Web of Science ID A1991FY79100003

    View details for PubMedID 1852810

  • THE ILIAC CREST CARTILAGINOUS CAP ANNALS OF PLASTIC SURGERY Schendel, S. A., Pearl, R. M. 1990; 25 (1): 29-31

    Abstract

    Bone and cartilage grafts can be procured from the ilium either separately or as composite chondroosseous grafts when sufficient cartilage is present. The thickness and anatomy of this iliac cartilaginous cap was analyzed in relationship to age in 50 individuals. Histology was that of normal hyaline cartilage. The cartilage alone was more pliable with little memory when compared with auricular or septal cartilage. The cartilage/bone junction was very strong. Cartilage thickness ran from close to 1 cm at age 5 to a diminished zero at age 25.

    View details for Web of Science ID A1990DN58200007

    View details for PubMedID 2378494

  • Sports related Nasal Injuries Sports Med Schendel, S. 1990; 18 (10): 59-74
  • TRANSORAL PLACEMENT OF RIGID FIXATION FOLLOWING SAGITTAL RAMUS SPLIT OSTEOTOMY JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY Tulasne, J. F., Schendel, S. A. 1989; 47 (6): 651-652

    View details for Web of Science ID A1989U841300029

    View details for PubMedID 2723868

  • PATHO-PHYSIOLOGY OF CLEFT-LIP MUSCLE PLASTIC AND RECONSTRUCTIVE SURGERY Schendel, S. A., Pearl, R. M., DeArmond, S. J. 1989; 83 (5): 777-784

    Abstract

    Although attention has been focused for decades on the correction of cleft lip deformities, our knowledge about the etiology of such deformities has remained presumptive. Sixty-six muscle biopsy specimens from cleft lip infants were obtained at the time of primary closure. Histochemical stains, histographic analysis, and electron microscopy were performed. A nonneurogenic muscle atrophy was seen that varied in severity, with muscle fibers near the cleft being the most atrophic and disorganized. Muscle fibers stained with the modified Gomori trichrome technique also demonstrated "ragged red" fibers typical of a mitochondrial myopathy. Electron microscopy confirmed large accumulations of mitochondria distorting the fibrils. These mitochondria also were increased in size and densely packed with cristae. This study thus demonstrates that the muscles in cleft lip deformities are not normal. Instead, they reflect either myopathy in the facial mesenchymal mitochondrion or at least a delay in maturation. We hypothesize that some of the morphologic deformities associated with cleft lip may cause a failure of mesenchymal reinforcement of the facial processes at a critical time in development.

    View details for Web of Science ID A1989U402700002

    View details for PubMedID 2469093

  • VANBUCHEM DISEASE - SURGICAL-TREATMENT OF THE MANDIBLE ANNALS OF PLASTIC SURGERY Schendel, S. A. 1988; 20 (5): 462-467

    Abstract

    First described in 1955, Van Buchem disease is an infrequently occurring hereditary sclerosing bone dysplasia. It is more properly called hyperostosis corticalis generalisata. The most striking feature is an unusual enlargement of the mandible with a normal dental occlusion. Skull base, spine, and pelvic bone involvement is also seen. The defect appears to be an increase in cortical bone thickness or sclerosis. The condition first appears around puberty in the autosomal recessive type and in early childhood with the autosomal dominant type. Reported here is a family with Van Buchem disease, in which surgical recontouring of the mandible was performed for one of the members. The surgery was performed by a combined intraoral/extraoral technique with good aesthetic results and minimal morbidity. A differential diagnosis and workup is also presented.

    View details for Web of Science ID A1988N220300011

    View details for PubMedID 3377422

  • COMPUTED AXIAL TOMOGRAPHIC ASSESSMENT OF CRANIOORBITAL ANATOMY IN UNILATERAL CLEFTS ANNALS OF PLASTIC SURGERY Schendel, S. A., Delaire, J. 1986; 17 (2): 120-124

    Abstract

    Anatomy of the cranioorbital region in the unoperated infant with cleft lip/palate, is not well known. In this study, computed axial tomography was performed in 7 infants with unoperated unilateral cleft lip combined with cleft palate but no recognized craniofacial syndromes, and on 5 age-matched control infants. Significant differences were found between the infants with cleft lip/palate and the normal infants. There was more plagiocephaly in the cleft group, and the flattened forehead on the involved side was associated with less facial projection. The angles of the petrous portions of the temporal bones and midsagittal plane were also significantly more obtuse in the cleft group. In the normal group the lateral orbital walls and petrous portions of the temporal bones formed a large symmetrical X. This X in the cleft groups was distorted and not readily recognizable. There were also trends indicating possible differences in the orbital and ethmoid orientations in the two groups.

    View details for Web of Science ID A1986D565700006

    View details for PubMedID 3273084

Conference Proceedings


  • Virtual reality based surgical assistance and training system for long duration space missions Montgomery, K., Thonier, G., Stephanides, M., Schendel, S. I O S PRESS. 2001: 315-321

    Abstract

    Access to medical care during long duration space missions is extremely important. Numerous unanticipated medical problems will need to be addressed promptly and efficiently. Although telemedicine provides a convenient tool for remote diagnosis and treatment, it is impractical due to the long delay between data transmission and reception to Earth. While a well-trained surgeon-internist-astronaut would be an essential addition to the crew, the vast number of potential medical problems necessitate instant access to computerized, skill-enhancing and diagnostic tools. A functional prototype of a virtual reality based surgical training and assistance tool was created at our center, using low-power, small, lightweight components that would be easy to transport on a space mission. The system consists of a tracked, head-mounted display, a computer system, and a number of tracked surgical instruments. The software provides a real-time surgical simulation system with integrated monitoring and information retrieval and a voice input/output subsystem. Initial medical content for the system has been created, comprising craniofacial, hand, inner ear, and general anatomy, as well as information on a number of surgical procedures and techniques. One surgical specialty in particular, microsurgery, was provided as a full simulation due to its long training requirements, significant impact on result due to experience, and likelihood for need. However, the system is easily adapted to realistically simulate a large number of other surgical procedures. By providing a general system for surgical simulation and assistance, the astronaut-surgeon can maintain their skills, acquire new specialty skills, and use tools for computer-based surgical planning and assistance to minimize overall crew and mission risk.

    View details for Web of Science ID 000169103300061

    View details for PubMedID 11317762

  • A single surgeon's experience with the Delaire palatoplasty Schendel, S. A., Lorenz, H. P., Dagenais, D., Hopkins, E., Chang, J. LIPPINCOTT WILLIAMS & WILKINS. 1999: 1993-1997

    Abstract

    The purpose of this review was to evaluate the clinical outcomes regarding velopharyngeal insufficiency and fistulization in patients with cleft palate who underwent primary repair with the one-stage Delaire palatoplasty. All patients who had a primary Delaire-type palatoplasty performed by the senior surgeon over a 10-year period (1988 to 1998) were studied. During this period, each consecutive patient with an open palatal cleft underwent the same type of repair by the same surgeon. Speech quality and velopharyngeal competence as determined by a single speech pathologist were recorded. A total of 95 patients were included in this series. The average length of follow-up was 31 months (range, 1 to 118 months). Average age at time of surgery was 13.3 months (range, 6 to 180 months). Thirty-one patients (32.6 percent) had significant associated anomalies. The average length of hospital stay was 1.9 days (range, 1 to 8 days) with a trend in recent years toward discharge on postoperative day 1. There were no intraoperative complications, either surgical or anesthetic. Three patients (3.2 percent) developed palatal fistula; none of them required repair. Six patients (6.3 percent) had velopharyngeal incompetence. In patients with more than 1 year of follow-up, the incidence of velopharyngeal incompetence was 9.2 percent (6 of 65). The incidence of fistula after the Delaire palatoplasty was lower than usually reported. The incidence of velopharyngeal incompetence requiring pharyngoplasty was equal to or lower than that seen after other types of palatoplasty, suggesting superior soft-palate muscle function attributable to approximation of the musculus uvulae. The Delaire palatoplasty results in a functional palate with low risk for fistula formation and velopharyngeal incompetence.

    View details for Web of Science ID 000083854900009

    View details for PubMedID 11149761

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