David Kahn

All Publications

• Where Do We Look? Assessing Gaze Patterns in Cosmetic Facelift Surgery with Eye Tracking Technology. Plastic and reconstructive surgery Cai, L. Z., Kwong, J. W., Azad, A. D., Kahn, D., Lee, G. K., Nazerali, R. S. 2019

  Abstract

  PURPOSE: Aesthetics plays a central role in determining success in plastic surgery. Understanding perceptions of favorable aesthetics is critical to ensure patient satisfaction. Eye-tracking technology offers an objective way to evaluate attention and understand how viewers direct their focus in patients who undergo cosmetic facelift procedures.METHODS: Thirty-six subjects ranging from layperson to attending plastic surgeon viewed 15 sets of photos before and after patients underwent an elective facelift procedure. They were instructed to evaluate the aesthetic quality on a Likert scale, while eye-tracking equipment tracked their gaze and analyzed their distribution of attention.RESULTS: Post-operative images showed a Likert score improvement of 0.51±0.26, with the greatest difference in attending cosmetic plastic surgeons (1.36±0.22; p<0.05). The nose was the most common first fixation location (31% of first fixations) and the most viewed area (16±3% of fixation time) for all subjects. Experienced subjects spent less time in non-relevant areas (30±11% for attending cosmetic plastic surgeons and 37±10% for attending non-cosmetic plastic surgeons) compared to less experienced subjects (50±15% for laypersons).CONCLUSIONS: This study demonstrates that viewers with greater experience in cosmetic surgery focus quickly on the cheeks, chin, and neck and have evenly distributed gaze across the entire face. These results suggest that laypersons' gaze are drawn to the center of the face - due to both unfamiliarity with the facelift procedure and the natural tendency to look at the central face - while attending plastic surgeons exhibit holistic gaze patterns and are more aware of the impact of the procedure.

  View details for PubMedID 30998662

• Where Do We Look? Assessing Gaze Patterns in Cosmetic Face-Lift Surgery with Eye Tracking Technology. Plastic and reconstructive surgery Cai, L. Z., Kwong, J. W., Azad, A. D., Kahn, D., Lee, G. K., Nazerali, R. S. 2019; 144 (1): 63–70

  Abstract

  Aesthetics plays a central role in determining success in plastic surgery. Understanding perceptions of favorable aesthetics is critical to ensure patient satisfaction. Eye-tracking technology offers an objective way of evaluating attention and understanding how viewers direct their focus on patients who undergo cosmetic face-lift procedures.Thirty-six subjects ranging from layperson to attending plastic surgeon viewed 15 sets of photographs before and after patients underwent an elective face-lift procedure. They were instructed to evaluate the aesthetic quality on a Likert scale while eye-tracking equipment tracked their gaze and analyzed their distribution of attention.Postoperative images showed a Likert score improvement of 0.51 ± 0.26, with the greatest difference in attending cosmetic plastic surgeons (1.36 ± 0.22; p < 0.05). The nose was the most common first fixation location (31 percent of first fixations) and the most viewed area (16 ± 3 percent of fixation time) for all subjects. Experienced subjects spent less time in nonrelevant areas (30 ± 11 percent for attending cosmetic plastic surgeons and 37 ± 10 percent for attending noncosmetic plastic surgeons) compared with less experienced subjects (50 ± 15 percent for laypersons).This study demonstrates that viewers with greater experience in cosmetic surgery focus quickly on the cheeks, chin, and neck and have evenly distributed gaze across the entire face. These results suggest that a layperson's gaze is drawn to the center of the face (because of both unfamiliarity with the face-lift procedure and the natural tendency to look at the central face), whereas attending plastic surgeons exhibit holistic gaze patterns and are more aware of the impact of the procedure.

  View details for DOI 10.1097/PRS.0000000000005700

  View details for PubMedID 31246802

• Delayed prosthetic breast reconstruction without the use of acellular dermal matrix EUROPEAN JOURNAL OF PLASTIC SURGERY Mittermiller, P. A., Nazerali, R. S., Glaus, S. W., Perez, M. G., Luan, A., Kahn, D. M., Lee, G. K. 2017; 40 (6): 533–40

  View details for DOI 10.1007/s00238-017-1300-4

  View details for Web of Science ID 000416142400007

• A novel thermal compression device for perioperative warming: a randomized trial for feasibility and efficacy BMC ANESTHESIOLOGY Maria, P., Maria, C., Eisenried, A., Velasquez, N., Kannard, B., Ramani, A., Kahn, D., Wheeler, A., Brock-Utne, J. 2017; 17: 102

  Abstract

  Inadvertent perioperative hypothermia (IPH) leads to surgical complications and increases length of stay. IPH rates are high with the current standard of care, forced air warming (FAW). Our hypothesis is that a prototype thermal compression device that heats the popliteal fossa and soles of the feet, with lower leg compression, increases perioperative temperatures and reduces IPH compared to the current standard of care.Thirty six female breast surgery patients, at a tertiary academic hospital, were randomized to the device or intraoperative FAW (stage I) with a further 18 patients randomized to the device with a single heating area only (stage II, popliteal fossa or sole of the feet). Stage I: 37 patients recruited (final 36). Stage II: 18 patients recruited (final 18).general anesthesia with esophageal monitoring for over 30 min, legs available and able to fit the device and no contraindications to leg heating or compression. The intervention was: Stage I: Investigational prototype thermal compression device (full device group) or intraoperative FAW. Stage II: Device with only a single heating location. Primary outcomes were perioperative temperatures and incidence of IPH. Secondary outcomes were local skin temperature, general and thermal comfort scores and presence of perioperative complications, including blood loss.Mean temperatures in the full device group were significantly higher than the FAW group in the pre-operative (36.7 vs 36.4 °C, p < 0.001), early intraoperative (36.3 vs 35.9 °C, p < 0.001), intraoperative (36.6 vs 36.2 °C, p < 0.001) and postoperative periods (36.8 vs 36.5 °C, p < 0.001). The incidence of IPH in the device group was also significantly lower (16.7% vs 72.0%, p = 0.001). Thermal comfort scores were significantly higher in the full device group and hypothermia associated wound complications were higher in the FAW group.The thermal compression device is feasible and has efficacy over the FAW. Further studies are recommended to investigate clinically significant outcomes.clinicaltrials.gov ( NCT02155400 ).

  View details for PubMedID 28800725

• Intraoperative imaging of nipple perfusion patterns and ischemic complications in nipple-sparing mastectomies. Annals of surgical oncology Wapnir, I., Dua, M., Kieryn, A., Paro, J., Morrison, D., Kahn, D., Meyer, S., Gurtner, G. 2014; 21 (1): 100-106

  Abstract

  Nipple-sparing mastectomies (NSM) have gained acceptance in the field of breast oncology. Ischemic complications involving the nipple-areolar complex (NAC) occur in 3-37 % of cases. Skin perfusion can be monitored intraoperatively using indocyanine green (IC-GREEN™, ICG) and a specialized infrared camera-computer system (SPY Elite™). The blood flow pattern to the breast skin and the NAC were evaluated and a classification scheme was developed.Preincision baseline and postmastectomy skin perfusion studies were performed intraoperatively using 3 mL of ICG. The pattern of arterial blood inflow was classified according to whether perfusion appeared to originate predominantly from the underlying breast tissue (V1), the surrounding skin (V2), or a combination of V1 and V2 (V3). Ischemia, resection, or delayed complications of NAC were recorded.Thirty-nine breasts were interrogated. Seven (18 %) demonstrated a V1 pattern, 18 (46 %) a V2 pattern, and 14 (36 %) a V3 pattern. Seven (18 %) NACs were removed; six intraoperatively and the seventh in a delayed fashion. Notably, five of the seven resected NACs had a V1 pattern. Overall, 71 % of all V1 cases demonstrated profound ischemic changes by intraoperative clinical judgment and SPY imaging. The rates of resection of the NAC differed significantly between perfusion patterns (Fisher's exact test, p = 0.0003).Three perfusion patterns for the NAC are defined. The V1 pattern had the highest rate of NAC ischemia in NSM. Imaging NAC and skin perfusion during NSMs is a useful adjunctive tool with potential to direct placement of mastectomy incisions and minimize ischemic complications.

  View details for DOI 10.1245/s10434-013-3214-0

  View details for PubMedID 24046104

• Nipple Reconstruction: Risk Factors and Complications after 189 Procedures. European journal of plastic surgery Momeni, A., Ghaly, M., Gupta, D., Karanas, Y. L., Kahn, D. M., Gurtner, G. C., Lee, G. K. 2013; 36 (10): 633-638

  Abstract

  A multitude of different approaches have been proposed for achieving optimal aesthetic results after nipple reconstruction. In contrast, however, only a few studies focus on the morbidity associated with this procedure, particularly after implant-based breast reconstruction.Using a cross-sectional study design all patients who underwent implant-based breast reconstruction with subsequent nipple reconstruction between 2000 and 2010 at Stanford University Medical Center were identified. The aim of the study was to analyze the impact of the following parameters on the occurrence of postoperative complications: age, final implant volume, time interval from placement of final implant to nipple reconstruction, and history of radiotherapy.A total of 139 patients with a mean age of 47.5 years (range, 29 to 75 years) underwent 189 nipple reconstructions. The overall complication rate was 13.2 percent (N = 25 nipple reconstructions). No association was observed between age (p = 0.43) or implant volume (p = 0.47) and the occurrence of complications. A trend towards higher complication rates in patients in whom the time interval between final implant placement and nipple reconstruction was greater than 8.5 months was seen (p = 0.07). Radiotherapy was the only parameter that was associated with a statistically significant increase in postoperative complication rate (51.7 percent vs. 6.25 percent; p < 0.00001).While nipple reconstruction is a safe procedure after implant-based breast reconstruction in patients without a history of radiotherapy, the presence of an irradiated field converts it to a high-risk one with a significant increase in postoperative complication rate. Patients with a history of radiotherapy should be informed about their risk profile and as a result may choose autologous reconstruction instead.IV.

  View details for PubMedID 24072956

• Nipple reconstruction after implant-based breast reconstruction: A "matched-pair" outcome analysis focusing on the effects of radiotherapy. Journal of plastic, reconstructive & aesthetic surgery : JPRAS Momeni, A., Ghaly, M., Gupta, D., Gurtner, G., Kahn, D. M., Karanas, Y. L., Lee, G. K. 2013; 66 (9): 1202-1205

  Abstract

  BACKGROUND: The major focus of research when addressing nipple reconstruction has been on developing new techniques to provide for long-lasting nipple projection. Rarely, has the outcome of nipple reconstruction as it relates to postoperative morbidity, particularly after implant-based breast reconstruction, been analyzed. METHODS: A "matched-pair" study was designed to specifically answer the question whether a history of radiotherapy predisposes to a higher complication rate after nipple reconstruction in patients after implant-based breast reconstruction. Only patients with a history of unilateral radiotherapy who underwent bilateral mastectomy and implant-based breast reconstruction followed by bilateral nipple reconstruction were included in the study. RESULTS: A total of 17 patients (i.e. 34 nipple reconstructions) were identified who met inclusion criteria. The mean age of the study population was 43.5 years (range, 23-69). Complications were seen after a total of 8 nipple reconstructions (23.5 percent). Of these, 7 complications were seen on the irradiated side (41.2 percent) (p = 0.03). CONCLUSION: While nipple reconstruction is a safe procedure after implant-based breast reconstruction in patients without a history of radiotherapy the presence of an irradiated field converts it to a procedure with a significant increase in postoperative complication rate.

  View details for DOI 10.1016/j.bjps.2013.04.052

  View details for PubMedID 23664573

• Facial Bone Density: Effects of Aging and Impact on Facial Rejuvenation AESTHETIC SURGERY JOURNAL Shaw, R. B., Katzel, E. B., Koltz, P. E., Kahn, D. M., Puzas, E. J., Langstein, H. N. 2012; 32 (8): 937-942

  Abstract

  Facial bone aging has recently been described as primarily resulting from volume loss and morphologic changes to the orbit, midface, and mandible.The authors demonstrate how the facial skeleton bone mineral density (BMD) changes with age in both men and women and compare these changes to those of the axial skeleton. They also explore the aesthetic implications of such changes in bone density.Dual-energy X-ray absorptiometry (DXA) scans of the facial bones and lumbar spine were obtained from 60 white subjects, 30 women and 30 men. There were 10 men and 10 women in each of 3 age categories: young (20-40 years), middle (41-60 years), and old (61+ years). The following measurements were obtained: lumbar spine BMD (average BMD of L1-L4 vertebrae), maxilla BMD (the average BMD of the right and left maxilla), and mandible BMD (the average BMD of the right and left mandibular ramus).The lumbar spine BMD decreased significantly for both sexes between the middle and old age groups. There was a significant decrease in the maxilla and mandible BMD for both sexes between the young and middle age groups.Our results suggest that the BMD of the face changes with age, similar to the axial skeleton. This change in BMD may contribute to the appearance of the aging face and potentially affect facial rejuvenation procedures.

  View details for DOI 10.1177/1090820X12462865

  View details for Web of Science ID 000310718000002

  View details for PubMedID 23012659

• Growth and Development of the Orbit ORAL AND MAXILLOFACIAL SURGERY CLINICS OF NORTH AMERICA Berger, A. J., Kahn, D. 2012; 24 (4): 545-?

  Abstract

  Every surgeon operating on the face, and particularly around the eye, should possess a working knowledge of the critical details related to development of the human orbit and recognized changes that occur during the course of aging. The anatomy of the orbit and periorbital region is complex, and the diagnosis and treatment of patients with orbital/periorbital disease requires expertise in congenital differences and awareness of the changes that occur as individuals age.

  View details for DOI 10.1016/j.coms.2012.08.001

  View details for Web of Science ID 000311873900004

  View details for PubMedID 23107427

• Aging of the Facial Skeleton: Aesthetic Implications and Rejuvenation Strategies PLASTIC AND RECONSTRUCTIVE SURGERY Shaw, R. B., Katzel, E. B., Koltz, P. F., Yaremchuk, M. J., Girotto, J. A., Kahn, D. M., Langstein, H. N. 2011; 127 (1): 374-383

  Abstract

  Facial aging is a dynamic process involving the aging of soft-tissue and bony structures. In this study, the authors demonstrate how the facial skeleton changes with age in both male and female subjects and what impact these structural changes may have on overall facial aesthetics.Facial bone computed tomographic scans were obtained from 60 female and 60 male Caucasian subjects. Twenty male and 20 female subjects were placed in three age categories (20 to 40 years, 41 to 64 years, and 65 years and older). Each computed tomographic scan underwent three-dimensional reconstruction with volume rendering. Edentulous patients were excluded. The following measurements were obtained: upper face (orbital aperture area, orbital aperture width, and curvilinear analysis of the superior and inferior orbital rims), midface (glabellar angle, pyriform angle, maxillary angle, and pyriform aperture area), and lower face (bigonial width, ramus breadth, ramus height, mandibular body height, mandibular body length, and mandibular angle).The orbital aperture width and orbital aperture area increased significantly with age for both sexes. There was a significant increase in orbital aperture size (increase in height of the superomedial and inferolateral orbital rim) in both sexes. The glabellar and maxillary angles decreased significantly with age for both sexes, whereas the pyriform aperture area significantly increased for both sexes with age. Mandibular length and height both decreased significantly for each sex. The mandibular angle significantly increased with age for both sexes.These results suggest that the skeletal morphology of the face changes with age. This change in skeletal morphology may contribute to the appearance of the aging face.

  View details for DOI 10.1097/PRS.0b013e3181f95b2d

  View details for Web of Science ID 000285992100051

  View details for PubMedID 20871486

• Effectiveness of the Asteame Nipple Guard (TM) in maintaining projection following nipple reconstruction: A prospective randomised controlled trial 42nd Congress of the European-Society-for-Surgical-Research Rosing, J. H., Momeni, A., Kamperman, K., Kahn, D., Gurtner, G., Lee, G. K. ELSEVIER SCI LTD. 2010: 1592–96

  Abstract

  As the final step in breast reconstruction, nipple reconstruction is considered a minor surgical procedure. However, despite the multitude of techniques and postoperative dressings proposed, none have proven to resist the tendency of the reconstructed nipple to gradually flatten over time. A prospective randomized controlled trial was conducted assessing the value of using the Asteame Nipple Guard™ compared to standard gauze dressing in maintaining nipple projection postoperatively. A total of 30 nipple reconstructions in 22 patients were included in the study with randomisation of 15 nipples to each study arm. Nipple projection was measured at various time points postoperatively with calculation of the percent changes in nipple projection. The mean decrease in long-term nipple projection at 6 months in the experimental group was 46.6% vs. 71.8% in the control group (p<0.05). In conclusion, the Nipple Guard™ helps in maintaining nipple projection postoperatively.

  View details for DOI 10.1016/j.bjps.2009.10.006

  View details for Web of Science ID 000281655500003

  View details for PubMedID 19897430

• Overview of Current Thoughts on Facial Volume and Aging FACIAL PLASTIC SURGERY Kahn, D. M., Shaw, R. B. 2010; 26 (5): 350-355

  Abstract

  Facial aging is a dynamic process involving the aging of soft tissue and bony structures. Much is known in regards to how the face loses volume as the soft tissue structures age. Epidermal thinning and the decrease in collagen cause skin to lose its elasticity. Loss of fat, coupled with gravity and muscle pull, leads to wrinkling and the formation of dynamic lines. The aging process has also been shown to affect the facial bones. Multiple studies suggest that the bony aging of the orbit and midface is a process primarily of contraction and morphologic change. This loss of bony volume and projection may contribute to the aged appearance. In this review, we will demonstrate how specific soft tissue and bony aspects of the face change with age in both genders and what impact these structural changes may have on overall facial aesthetics.

  View details for DOI 10.1055/s-0030-1265024

  View details for Web of Science ID 000282253500003

  View details for PubMedID 20853225

• Aging of the Mandible and Its Aesthetic Implications PLASTIC AND RECONSTRUCTIVE SURGERY Shaw, R. B., Katzel, E. B., Koltz, P. F., Kahn, D. M., Girotto, J. A., Langstein, H. N. 2010; 125 (1): 332-342

  Abstract

  Facial aging is a dynamic process involving the aging of soft-tissue and bony structures. In this study, the authors demonstrate how specific bony aspects of the mandible change with age in both genders and what impact these structural changes may have on overall facial aesthetics.Facial bone three-dimensional computed tomographic scans were obtained from 120 Caucasian subjects (60 women and 60 men). Our study population consisted of 20 male and 20 female subjects in each of three age categories (20 to 40, 41 to 64, and > or = 65 years). Edentulous patients were excluded. The following measurements were obtained: bigonial width, ramus breadth, ramus height, mandibular body height, mandibular body length, and mandibular angle. The data were analyzed with one-way analysis of variance and two-tailed t tests, with results considered significant at a value of p < 0.05.There was no significant change with regard to bigonial width or ramus breadth across age groups for either gender. Ramus height, mandibular body height, and mandibular body length decreased significantly with age for both genders, whereas the mandibular angle increased significantly for both genders with increasing age.These results suggest that the bony elements of the mandible change significantly with age for both genders and that these changes, coupled with soft-tissue changes, lead to the appearance of the aged lower third of the face.

  View details for DOI 10.1097/PRS.0b013e3181c2a685

  View details for Web of Science ID 000273417000040

  View details for PubMedID 20048624

• Periorbital Skeletal Augmentation to Improve Blepharoplasty and Midfacial Results PLASTIC AND RECONSTRUCTIVE SURGERY Yaremchuk, M. J., Kahn, D. M. 2009; 124 (6): 2151-2160

  Abstract

  Narrow palpebral fissures, short lower lids, and full cheeks are hallmarks of youthful periorbita. The presence of these features is predicated on a convex upper midface skeleton. Faces whose midface skeletons are flat or concave do not manifest these youthful attributes, tend to age prematurely, and are prone to lower lid malposition after blepharoplasty.Augmentation of the infraorbital rim with alloplastic implants can provide convexity to the deficient upper midface skeleton. Suspension of the cheek soft tissues (subperiosteal midface lift) on this now supportive framework narrows the palpebral fissure, shortens the lower lid, and gives fullness to the cheek. The addition of lateral canthopexy to skeletal augmentation and subperiosteal midface lift can restore lower lid position when previous blepharoplasty has resulted in lower lid malposition in patients with deficient midface skeletons.This concept has been utilized in 87 patients (65 female, 22 male) over the last 7 years. Of these 87 patients, four patients (5 percent) required revision surgery to correct implant malposition or prominence. Three patients (3 percent) required implant removal to treat infection. Implants were later replaced in two of these three patients.Augmentation of the infraorbital rim with alloplastic implants provides convexity to the upper midface skeleton. Together with lower lid and midface soft-tissue suspension, it creates or restores youthful periorbital aesthetics.

  View details for DOI 10.1097/PRS.0b013e3181bcf5bc

  View details for Web of Science ID 000272615600048

  View details for PubMedID 19952674

• Two-year-old girl with cervicomedullary junction stenosis and an unknown type of skeletal dysplasia JOURNAL OF NEUROSURGERY-PEDIATRICS Cheshier, S. H., Kalani, M. Y., Pendakaur, A., Higgins, D., Kahn, D., Shendel, S., Shuer, L. 2008; 2 (3): 200-202

  Abstract

  The authors present a novel case of skeletal dysplasia in a 2.8-year-old girl. The patient presented with progressive lower cranial nerve palsy and myelopathy due to constriction at the cervicomedullary junction caused by overgrowth of the occipital bone of the foramen magnum and the C-1. She also had prominent bone overgrowth of the superior orbital ridges, resulting in excessive stretching of periorbital skin and an inability to fully close her eyes.

  View details for DOI 10.3171/PED/2008/2/9/200

  View details for Web of Science ID 000258903800010

  View details for PubMedID 18759602

• Aging of the bony orbit: a three-dimensional computed tomographic study. Aesthetic surgery journal Kahn, D. M., Shaw, R. B. 2008; 28 (3): 258-264

  Abstract

  Facial aging is a dynamic process involving the aging of soft tissue and bony structures. The shape, size, and volume of the bony orbit have all been shown to change with increasing age.In this study, we demonstrate how specific bony aspects of the orbit change with age in both male and female subjects and what impact this may have on the techniques used in facial cosmetic surgery.Facial bone computed tomography (CT) scans were obtained from 60 white subjects (30 female, 30 male). Our study population consisted of 10 male and 10 female subjects in each of 3 age categories. Each CT scan underwent three-dimensional (3-D) reconstruction with volume rendering. Orbital aperture width was measured as a line drawn from the posterior lacrimal crest to the frontozygomatic suture. This line was then used as the x-axis from which the distance to the superior and inferior orbital rim at nine equal increments (labeled 10 to 90) was obtained. The orbital aperture area was also measured on each 3-D model. The Student t test was used to identify any trends between age groups.The orbital aperture width and area in both our male and female subjects showed a significant increase with increasing age. There was a significant increase in height of the superior orbital rim medially in both genders, suggesting that the superior orbital rim receded with age in this region. The inferior orbital rim receded significantly laterally in our female population, while our male subjects had a recession of the entire inferior orbital rim.These results suggest that the bony elements of the orbit change dramatically with age, and this, coupled with soft tissue changes, can lead to the appearance of the aged eye and orbit.

  View details for DOI 10.1016/j.asj.2008.02.007

  View details for PubMedID 19083535

• Internal maxillary distraction with a new bimalar device 62nd Annual Meeting of the American-Cleft-Palate-Craniofacial-Association Kahn, D. M., Broujerdi, J., Schendel, S. A. W B SAUNDERS CO-ELSEVIER INC. 2008: 675–83

  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

• The timing of implant exchange in the development of capsular contracture after breast reconstruction. Eplasty Weintraub, J. L., Kahn, D. M. 2008; 8

  Abstract

  Capsular contracture is a common complication associated with reconstructive breast surgery. The optimal time interval between the completion of tissue expansion and placement of the permanent implant is arbitrary and incompletely studied in the literature. The aim of the study was to determine whether the time interval between completion of expansion and placement of the permanent implant would affect the incidence of capsular contracture.We conducted a retrospective study of 112 patients with breast cancer, including 140 breasts, who underwent postmastectomy tissue expander placement between 1997 and 2004. All patients underwent replacement of tissue expander with a permanent prosthesis. Data were collected retrospectively, including whether the patient smoked, underwent radiation therapy, had saline or silicone implant reconstruction, required reoperation after tissue expander placement or after permanent implant placement, Baker classification, and the interval between completion of expansion and placement of permanent implant.We used a logistic regression model to incorporate the predictors of capsular contracture. Keeping all other predictors constant, we found that the time interval between implant exchange had no effect on capsular contracture. The only significant predictor of capsular contracture was whether the patient required a reoperation after the permanent implant was placed (P = .0001).Allowing the capsule around a tissue expander to mature does not significantly affect development of capsular contracture. However, a complication that necessitates disrupting the periprosthetic capsule of the permanent implant with an operation significantly increases odds of developing contracture.

  View details for PubMedID 18587490

• 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

• Broad nasal bone reduction: An algorithm for osteotomies PLASTIC AND RECONSTRUCTIVE SURGERY Gruber, R., Chang, T. N., Kahn, D., Sullivan, P. 2007; 119 (3): 1044-1053

  Abstract

  A persistent problem with nasal bone osteotomies is inadequate reduction of the width of the nasal dorsum. In addition, an algorithm as to which osteotomy to use has not been fully explored.Nine cadavers received a medial oblique osteotomy (15 to 30 degrees off midline) following a humpectomy in six. On one side, the osteotomy was performed on the medial side of the apex of the open roof. On the contralateral side, it was performed on the lateral side of the apex. The osteotome was then pried posteriorly. The resultant hemidorsal widths were compared. Clinically, 53 patients were classified into the following: type I, broad nasal base (lateral osteotomy only); type II, broad nasal base and broad dorsum (lateral and medial oblique osteotomy); and type III, broad dorsum only (medial oblique osteotomy only).The reduction in hemidorsal width was greatest when the osteotome was placed on the lateral side of the apex (t test, p < 0.008). The improved width reduction was attributable to the slippage of the lateral nasal bone under the dorsal hood of the nasal bone. A lateral osteotomy did not have to be performed to reduce the dorsal width alone. After 15 to 32 months, nasal bone width was satisfactory in all but three cases, one of which required a revision.Reduction of the nasal dorsal width is facilitated by a medial oblique osteotomy alone if it is placed at the lateral aspect of the apex of the open roof. A classification of broad nasal bones is given that emphasizes the distinction between dorsal width and nasal base width and suggests which osteotomy to use.

  View details for DOI 10.1097/01.prs.0000252504.65746.18

  View details for Web of Science ID 000244438700036

  View details for PubMedID 17312512

• Aging of the midface bony elements: A three-dimensional computed tomographic study PLASTIC AND RECONSTRUCTIVE SURGERY Shaw, R. B., Kahn, D. M. 2007; 119 (2): 675-681

  Abstract

  The face loses volume as the soft-tissue structures age. In this study, the authors demonstrate how specific bony aspects of the face change with age in both men and women and what impact this may have on the techniques used in facial cosmetic surgery.Facial bone computed tomographic scans were obtained from 60 Caucasian patients (30 women and 30 men). The authors' study population consisted of 10 male and 10 female subjects in each of three age categories. Each computed tomographic scan underwent three-dimensional reconstruction with volume rendering, and the following measurements were obtained: glabellar angle (maximal prominence of glabella to nasofrontal suture), pyriform angle (nasal bone to lateral inferior pyriform aperture), and maxillary angle (superior to inferior maxilla at the articulation of the inferior maxillary wing and alveolar arch). The pyriform aperture area was also obtained. The t test was used to identify any trends between age groups.The glabellar and maxillary angle in both the male and female subjects showed a significant decrease with increasing age. The pyriform angle did not show a significant change between age groups for either sex. There was a significant increase in pyriform aperture area from the young to the middle age group for both sexes.These results suggest that the bony elements of the midface change dramatically with age and, coupled with soft-tissue changes, lead to the appearance of the aged face.

  View details for DOI 10.1097/01.prs.0000246596.79795.a8

  View details for Web of Science ID 000243584300031

  View details for PubMedID 17230106

• Laparoscopic repair for recurrent abdominal wall hernia after TRAM flap breast reconstruction - Case report of 2 patients ANNALS OF PLASTIC SURGERY Shaw, R. B., Curet, M. J., Kahn, D. M. 2006; 56 (4): 447-450

  Abstract

  The transverse rectus abdominis musculocutaneous (TRAM) flap is an appealing option for women choosing between various breast reconstructive techniques as it results in an autologous reconstructed breast that is soft and mimics a natural breast. Despite these benefits, there are complications with this procedure, such as pain at the donor site, longer scars, and most frequently the occurrence of abdominal wall hernia or bulge, which has been reported in up to 20%-40% of patients.In this case report, we share our experience with 2 patients who had multiple open hernia repairs, 5 between the 2 of them, after their TRAM flap surgery. Each of these 5 repairs was performed with a Prolene mesh overlay, but not one lasted for more than 6 months. After reviewing our patients' records and our surgical options, we decided to proceed with laparoscopic repair of their recurrent hernias.The patients are now at postoperative follow-up of 12 months and 15 months, with no evidence of recurrence.Laparoscopic surgery has many benefits, such as shorter hospitalization and decreased pain. For our patients, it also resulted in a more beneficial and longer-lasting repair. We believe that this is partly due to the mechanics of the repair, which allows the abdominal contents to buttress the mesh against the abdominal wall. In addition, we believe that this technique reinforces the posterior sheath, which may not be accomplished in an open repair. This is important as most hernias after TRAM flap surgery occur below the arcuate line. From our experience with these 2 patients, we now advocate the use of laparoscopic repair as a treatment option for those who present with recurrent abdominal wall hernia or bulge after their TRAM flap surgery and believe with more experience it will become a first-line treatment.

  View details for DOI 10.1097/01.sap.0000200281.24169.1f

  View details for Web of Science ID 000236376900025

  View details for PubMedID 16557083

• Asian-American Rhinoplasty Aesthetic Surgery Journal Gruber R, Kuang A, Kahn D 2004; 24 (5): 423-430
• A novel semi-buried curvilinear osteodistractor for the mandible 3rd International Congress of Craniofacial and Maxillofacial Distraction Schendel, S. A., Safa, B., Kahn, D. MEDIMOND S R L. 2001: 287–289

  View details for Web of Science ID 000172402500045

• Biomechanics of mandibular distraction osteogenesis 3rd International Congress of Craniofacial and Maxillofacial Distraction Safa, B., Kahn, D., Lorenz, H. P., Heegaard, J. H., Kosek, J., Schendel, S. A. MEDIMOND S R L. 2001: 27–32

  View details for Web of Science ID 000172402500005

• A preliminary report on the use of semi-buried curvilinear distractor in the human mandible 3rd International Congress of Craniofacial and Maxillofacial Distraction Schendel, S., Kahn, D., Linck, D., Hopkins, E. MEDIMOND S R L. 2001: 255–258

  View details for Web of Science ID 000172402500039