Bio

Clinical Focus


  • Dupuytren Contracture
  • Hand and Upper Extremity Surgery
  • Peripheral nerve injuries
  • Malignant Peripheral Nerve Sheath Tumors
  • Plastic and Reconstructive Surgery
  • Obstetrical brachial plexus palsy
  • Brachial plexus
  • Hand and Upper Extremity Surgery, Pediatric
  • Plastic Surgery

Professional Education


  • Residency:Stanford University School of Medicine (1974) CA
  • Residency:Stanford University School of Medicine (1973) CA
  • Internship:Stanford University School of Medicine (1969) CA
  • Board Certification: Plastic Surgery, American Board of Plastic Surgery (1977)
  • Fellowship:Roosevelt Hospital (1975) NY
  • Medical Education:University of Florida (1968) FL

Research & Scholarship

Current Research and Scholarly Interests


1. Nerve regeneration and repair, evaluation of repair methods, modalities to enhance peripheral nerve regeneration, development of improved methods to analyze nerve regeneration.

2. Implementation of functional neuromuscular stimulation to paralytic deformities.

3. Computer modeling of upper limb function.

Teaching

2013-14 Courses


Postdoctoral Advisees


Publications

Journal Articles


  • The Treatment of Dupuytren Disease JOURNAL OF HAND SURGERY-AMERICAN VOLUME Desai, S. S., Hentz, V. R. 2011; 36A (5): 936-942

    Abstract

    The treatment of progressive Dupuytren contractures has historically been and continues to be largely surgical. Although a number of surgical interventions do exist, limited palmar fasciectomy continues to be the most common and widely accepted treatment option. Until recently, nonsurgical options were limited and clinically ineffective. However, the commercial availability and recent approval of collagenase clostridium histolyticum now provides practitioners with a nonsurgical approach to this disease. This article presents a comprehensive review of the surgical and nonsurgical treatments of Dupuytren disease, with a focus on collagenase.

    View details for DOI 10.1016/j.jhsa.2011.03.002

    View details for Web of Science ID 000290185700030

    View details for PubMedID 21527148

  • Biceps-to-triceps transfer technique. journal of hand surgery Endress, R. D., Hentz, V. R. 2011; 36 (4): 716-721

    Abstract

    Lack of voluntary active elbow extension inhibits many important functions in persons with tetraplegia. Biceps-to-triceps transfer can restore this function in selected patients. This article outlines the basic problem, indications and contraindications, surgical technique, and postoperative rehabilitation protocol for biceps-to-triceps transfer using the medial routing technique with suture anchoring of the biceps muscle tendon unit into the triceps aponeurosis and olecranon.

    View details for DOI 10.1016/j.jhsa.2011.01.028

    View details for PubMedID 21463733

  • Collagenase clostridium histolyticum for Dupuytren's contracture EXPERT OPINION ON BIOLOGICAL THERAPY Desai, S. S., Hentz, V. R. 2010; 10 (9): 1395-1404

    Abstract

    Dupuytren's disease is a non-malignant, progressive disorder of the hands that can severely limit hand function and diminish overall quality of life. With global life expectancy increasing, the prevalence of this disease appears to be increasing amongst all ethnic groups. Treatment has traditionally remained surgical with few effective, nonsurgical options. However, with the introduction of collagenase clostridium histolyticum to treat Dupuytren's contractures, physicians and surgeons may be provided with a new, office-based, non-surgical option to treat this disease.The literature behind the use of collagenase to treat Dupuytren's disease; including its mechanism of action, safety, efficacy and clinical evidence behind its recent FDA approval.The latest information available on collagenase through a comprehensive review of PubMed and the websites of licensing organizations for medicinal products.Phase III, clinical trials on collagenase for treatment of Dupuytren's contractures have recently been completed. Meeting primary and secondary objectives, collagenase has obtained FDA approval for clinical use. Collagenase now provides a non-operative option for Dupuytren's disease. Although short-term results show that collagenase is safe and efficacious, long-term effects of repeat injections and contracture recurrence rates have yet to be examined.

    View details for DOI 10.1517/14712598.2010.510509

    View details for Web of Science ID 000281614500010

    View details for PubMedID 20666587

  • Collagenase injection as nonsurgical treatment of Dupuytren's disease: 8-year follow-up. journal of hand surgery Watt, A. J., Curtin, C. M., Hentz, V. R. 2010; 35 (4): 534-?

    Abstract

    Collagenase has been investigated in phase II and phase III clinical trials for the treatment of Dupuytren's disease. The purpose of this study is to report 8-year follow-up results in a subset of patients who had collagenase injection for the treatment of Dupuytren's contracture.Twenty-three patients who participated in the phase II clinical trial of injectable collagenase were contacted by letter and phone. Eight patients were enrolled, completed a Dupuytren's disease questionnaire, and had independent examination of joint motion by a single examiner.Eight patients completed the 8-year follow-up study: 6 had been treated for isolated metacarpophalangeal (MCP) joint contracture, and 2 had been treated for isolated proximal interphalangeal (PIP) joint contracture. Average preinjection contracture was 57 degrees in the MCP group. Average contracture was 9 degrees at 1 week, 11 degrees at 1 year, and 23 degrees at 8-year follow-up. Four of 6 patients experienced recurrence, and 2 of 6 had no evidence of disease recurrence at 8-year follow-up. Average preinjection contracture was 45 degrees in the PIP group. Average contracture was 8 degrees at 1 weeks, 15 degrees at 1 year, and 60 degrees at 8-year follow-up. Both patients experienced recurrence at 8-year follow-up. No patients had had further intervention on the treated finger in either the MCP or the PIP group. Patients subjectively rated the overall clinical success at 60%, and 88% of patients stated that they would pursue further injection for the treatment of their recurrent or progressive Dupuytren's disease.Enzymatic fasciotomy is safe and efficacious, with initial response to injection resulting in reduction of joint contracture to within 0 degrees -5 degrees of normal in 72 out of 80 patients. Initial evaluation of long-term recurrence rates suggests disease recurrence or progression in 4 out of 6 patients with MCP contractures and 2 patients with PIP contractures; however, recurrence was generally less severe than the initial contracture in the MCP group. In addition, patient satisfaction was high.

    View details for DOI 10.1016/j.jhsa.2010.01.003

    View details for PubMedID 20353858

  • The management of the upper limb in incomplete lesions of the cervical spinal cord HAND CLINICS Hentz, V. R., Leclercq, C. 2008; 24 (2): 175-?

    Abstract

    Patients with incomplete cervical spinal cord injuries present unique challenges for the reconstructive surgeon. For example, their patterns of injury don't easily fit into the International Classification system familiar to surgeons; they don't lend themselves to a "recipe" approach to surgical decision-making; and they frequently have developed upper limb deformities that must be addressed before any consideration is made for functional surgery. Meanwhile, little has been published regarding surgery for these patients. This article summarizes issues related to evaluating and planning surgical procedures for the upper limb in incomplete lesions of the cervical spinal cord.

    View details for DOI 10.1016/j.hcl.2008.01.003

    View details for Web of Science ID 000256444800006

    View details for PubMedID 18456124

  • MOC-PS(SM) CME article: self-assessment and performance in practice: the carpal tunnel. Plastic and reconstructive surgery Hentz, V. R., Lalonde, D. H. 2008; 121 (4): 1-10

    Abstract

    After studying the article, the participant should be able to: 1. Conduct an appropriate history and physical examination for a patient suspected of having carpal tunnel syndrome. 2. Understand the role of provocative and other diagnostic tests pertinent to the diagnosis of carpal tunnel syndrome. 3. Understand the goals of the surgical treatment of carpal tunnel syndrome and how to obtain these. 4. Appreciate the common complications of carpal tunnel surgery and their management.The purpose of this article is to review important aspects of the history, physical examination, diagnosis, and management of carpal tunnel syndrome. Associated diseases, predisposing factors, and prognostic features are explored. The significance of diagnostic studies and the variety of anesthetic techniques with which to perform the surgery are reviewed. Evidence regarding the different surgical approaches, such as the open versus the endoscopic, is examined. Postoperative care issues such as therapy and splinting are examined. Finally, complications of carpal tunnel surgery and their management are outlined.

    View details for DOI 10.1097/01.prs.0000305930.24851.26

    View details for PubMedID 18379382

  • Dupuytren's Disease: History, Diagnosis, and Treatment PLASTIC AND RECONSTRUCTIVE SURGERY Shaw, R. B., Chong, A. K., Zhang, A., Hentz, V. R., Chang, J. 2007; 120 (3): 44E-54E

    Abstract

    After studying this article, the participant should be able to: 1. Describe the clinical features of the disease. 2. Describe the pathoanatomical structures in Dupuytren's disease. 3. Outline the various factors associated with Dupuytren's disease. 4. Describe the modalities for surgical and nonsurgical treatment of the condition. 5. Outline recent biomolecular knowledge about the basis of Dupuytren's disease.Dupuytren's disease is characterized by nodule formation and contracture of the palmar fascia, resulting in flexion deformity of the fingers and loss of hand function. The authors review the historical background, clinical features, and current therapy of Dupuytren's disease; preview treatment innovations; and present molecular data related to Dupuytren's disease. These new findings may improve screening for Dupuytren's disease and provide a better understanding of the disease's pathogenesis.

    View details for DOI 10.1097/01.prs.0000278455.63546.03

    View details for Web of Science ID 000207677600001

    View details for PubMedID 17700106

  • Tumours of the hand LANCET ONCOLOGY Hsu, C. S., Hentz, V. R., Yao, J. 2007; 8 (2): 157-166

    Abstract

    Hand tumours of soft-tissue and bony origin are frequently encountered, and clinicians must be able to distinguish typical benign entities from life-threatening or limb-threatening malignant diseases. In this Review, we present a diagnostic approach to hand tumours and describe selected cancers and their treatments. Soft-tissue tumours include ganglion cysts, giant-cell cancers and fibromas of the tendon sheath, epidermal inclusion cysts, lipomas, vascular lesions, peripheral-nerve tumours, skin cancers, and soft-tissue sarcomas. Bony tumours encompass enchondromas, aneurysmal bone cysts, osteoid osteomas, giant-cell lesions of bone, bone sarcomas, and metastases. We look at rates of recurrence and 5-year survival, and recommendations for adjunct chemotherapy and radiotherapy for malignant lesions.

    View details for Web of Science ID 000244103100028

    View details for PubMedID 17267330

  • Is microsurgical treatment of brachial plexus palsy better than conventional treatment? HAND CLINICS Hentz, V. R. 2007; 23 (1): 83-?

    Abstract

    There are some plexus injuries for which microneural plexus reconstruction provides the only good possibility of achieving useful limb function. These injuries include complete plexus palsies in the adult and baby, and incomplete upper plexus lesions in the adult. There are plexus injuries for which there is little to no role for microneurosurgery, such as the isolated C8, T1 injury in the adult (this is an extremely rare injury in babies). This article explores conventional versus microneurosurgical reconstruction for adult traumatic and birth-related brachial plexus palsies.

    View details for DOI 10.1016/j.hcl.2007.01.006

    View details for Web of Science ID 000246911500009

    View details for PubMedID 17478255

  • Variability in surgical technique for brachioradialis tendon transfer - Evidence and implications JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME Murray, W. M., Hentz, V. R., Friden, J., Lieber, R. L. 2006; 88A (9): 2009-2016

    Abstract

    Transfer of the tendon of the brachioradialis muscle to the tendon of the flexor pollicis longus restores lateral pinch function after cervical spinal cord injury. However, the outcomes of the procedure are unpredictable, and the reasons for this are not understood. The purpose of this study was to document the degree of variability observed in the performance of this tendon transfer.The surgical technique used for the brachioradialis tendon transfer was assessed in two ways. First, the surgical attachment length of the brachioradialis was quantified, after transfer to the flexor pollicis longus, with use of intraoperative laser diffraction to measure muscle sarcomere length in eleven individuals (twelve limbs) with tetraplegia. Second, ten surgeons who regularly performed this procedure were surveyed regarding their tensioning preferences. Using a biomechanical model of the upper extremity, we investigated theoretically the effect of different surgical approaches on the active muscle-force-generating capacity of the transferred brachioradialis in functionally relevant elbow, wrist, and hand postures.The average sarcomere length (and standard deviation) of the transferred brachioradialis was 3.5 +/- 0.3 mum. That length was significantly correlated to the in situ sarcomere length (r(2) = 0.53, p < 0.05). Surgical tensioning preferences varied considerably; however, six of the ten surgeons positioned the patient's elbow between full extension (0 degrees of elbow flexion) and 50 degrees of flexion when selecting the attachment length, and six of the ten stated that their goal was to tension the transfer slightly tighter than its resting tension. The computer simulations suggested that a "tighter" brachioradialis transfer would produce its peak active force in an elbow position that is more flexed than the elbow position in which a "looser" transfer would produce its peak active force.This study provides evidence that experienced surgeons perform this tendon transfer differently from one another. Biomechanical simulations suggested that these differences could result in substantial variability in the active force that the transferred brachioradialis can produce in functionally relevant postures.The surgical attachment length and the position of the patient's limb at the time of tendon transfer are both controllable and measurable parameters. Understanding the relationship between surgical technique and postoperative muscle function may provide surgeons with more control of clinical outcomes.

    View details for DOI 10.2106/JBJS.E.00973

    View details for Web of Science ID 000240470900015

  • Activation of brachioradialis muscles transferred to restore lateral pinch in tetraplegia JOURNAL OF HAND SURGERY-AMERICAN VOLUME Johanson, A. E., Hentz, V. R., Smaby, N., Murray, W. A. 2006; 31A (5): 747-753

    Abstract

    Surgical transfers of muscles are used to restore lateral pinch in tetraplegia; however, outcomes are variable. The purpose of this study was to compare activation of the brachioradialis (Br) after transfer to the flexor pollicis longus during maximum effort in its primary function (elbow flexion) with maximum effort in its postoperative function (lateral pinch) and to record Br activation during functional tasks.Fine-wire electrodes recorded activation of the Br in 11 arms with tetraplegia. Subjects produced maximum lateral pinch force with and without elbow stabilization and were classified according to elbow strength. The elbow was stabilized by supporting the arm and limiting elbow motion. A force sensor mounted on a custom grip recorded the pinch force. Electromyographic (EMG) signals recorded during lateral pinch were expressed as a percentage of the maximum voluntary contraction recorded during maximum-effort elbow flexion.The EMG activation was significantly lower during lateral pinch compared with resisted elbow flexion. The mean EMG during lateral pinch in the self-supported elbow condition was 34% of the maximum voluntary contraction; with the elbow stabilized the EMG increased to 55% of the maximum voluntary contraction. Postoperative pinch-force magnitude was 14 N with self-support and 20 N with the elbow stabilized. Subjects with weak elbow extension strength produced significantly lower pinch forces compared with subjects with strong elbow extension but had similar ability to activate the Br. The Br activation was higher when the pinch tasks were performed successfully.These findings suggest a reduced ability to activate the transferred muscle fully in lateral pinch function after surgery, even with the addition of elbow support. The Br activation is linked to successful performance of lateral pinch tasks. The subjects' inability to activate the transferred muscle fully may be affected by postoperative muscle re-education and contribute to postoperative weakness.

    View details for DOI 10.1016/j.jhsa.2006.01.006

    View details for Web of Science ID 000237881700010

  • Congenital brachial plexus exploration. Techniques in hand & upper extremity surgery Hentz, V. R. 2004; 8 (2): 58-69

    Abstract

    Stanford's experience in the management of obstetrical brachial plexus palsy dates from 1983. A formal clinic service began in 1992. The tenets of management include early evaluations, a dependency on sequential evolution for decision-making, and very early neural surgery for babies with abnormal hands. We watch babies with normal hands for a longer time before advising surgery. At exploration, common patterns of injury are observed. Intraoperative evoked potentials are used to make surgical decisions. Reconstructive goals for upper plexus injuries include shoulder and elbow control. The paramount goal for babies with global palsies is hand function. Therapy throughout the child's growth years is vital. Sequelae, particularly shoulder contractures, require early surgical intervention. Secondary reconstructive procedures are typically beneficial in improving function. Since 1992, over 400 children have been examined, 62 have had neural reconstruction, and 102 have undergone secondary procedures. Surgery has been remarkably complication free. All children having neural reconstruction except 2 have been benefited.

    View details for PubMedID 16518116

  • Identification of key pinch forces required to complete functional tasks JOURNAL OF REHABILITATION RESEARCH AND DEVELOPMENT Smaby, N., Johanson, M. E., Baker, B., Kenney, D. E., Murray, W. M., Hentz, V. R. 2004; 41 (2): 215-223

    Abstract

    Reconstructive hand surgeries restore key pinch to individuals with pinch force deficits caused by tetraplegia. Data that define the magnitudes of force necessary to complete functional key pinch tasks are limited. This study aims to establish target pinch forces for completing selected tasks that represent a range of useful functional activities. A robot arm instrumented with a force sensor completed the tasks and simultaneously measured the forces applied to the task objects. Lateral pinch force requirements were calculated from these measured object forces. Pinch force requirements ranged from 1.4 N to push a button on a remote to 31.4 N to insert a plug into an outlet. Of the tasks studied, 9 of 12 required less than 10.5 N. These pinch force requirements, when compared to pinch forces produced by 14 individuals with spinal cord injuries (with and without surgical reconstruction of pinch), accurately predicted success or failure in 81% of subject trials. The prediction errors indicate a need to measure other factors such as pinch opening, force location, force direction, and proximal joint control.

    View details for Web of Science ID 000221807600014

    View details for PubMedID 15558375

  • Biomechanics of the Steindler flexorplasty surgery: a computer simulation study. journal of hand surgery Saul, K. R., Murray, W. M., Hentz, V. R., Delp, S. L. 2003; 28 (6): 979-986

    Abstract

    Our goal was to investigate the capacity of a Steindler flexorplasty to restore elbow flexion to persons with C5-C6 brachial plexus palsy. In this procedure the origin of the flexor-pronator mass is moved proximally onto the humeral shaft. We examined how the choice of the proximal attachment site for the flexor-pronator mass affects elbow flexion restoration, especially considering possible side effects including limited wrist and forearm motion owing to passive restraint from stretched muscles.A computer model of the upper extremity was used to simulate the biomechanical consequences of various surgical alterations. Unimpaired, preoperative, and postoperative conditions were simulated. Seven possible transfer locations were used to investigate the effects of choice of transfer location.Each transfer site produced a large increase in elbow flexion strength. Transfer to more proximal attachment sites also produced large increases in passive resistance to wrist extension and forearm supination.To reduce detrimental side effects while achieving clinical goals our theoretical analysis suggests a transfer to the distal limit of the traditional transfer region.

    View details for PubMedID 14642514

  • Three-dimensional hyaluronic acid grafts promote healing and reduce scar formation in skin incision wounds. Journal of biomedical materials research. Part B, Applied biomaterials Hu, M., Sabelman, E. E., Cao, Y., Chang, J., Hentz, V. R. 2003; 67 (1): 586-592

    Abstract

    Hyaluronic acid (HA) has been found to play important roles in tissue regeneration and wound-healing processes. Fetal tissue with a high concentration of HA heals rapidly without scarring. The present study employed HA formed into three-dimensional strands with or without keratinocytes to treat full-thickness skin incision wounds in rats. Wound closure rates of HA strand grafts both with and without keratinocytes were substantially enhanced. The closure times of both HA grafts were less than 1 day (average 16 h), about 1/7 that of the contralateral control incisions (114 h, p <.01). Average wound areas after 10 days were HA-only graft: 0.151 mm2 +/- 0.035; HA + cell grafts: 0.143 mm2 +/- 0.036 and controls: 14.434 mm2 +/- 1.175, experimental areas were 1% of the controls (p < 0.01). Transforming growth factor (TGF) beta1 measured by immunostaining was remarkably reduced in HA-treated wounds compared to the controls. In conclusion, HA grafts appeared to produce a fetal-like environment with reduced TGF-beta1, which is known to be elevated in incipient scars. The HA strands with or without cultured cells may potentially improve clinical wound healing as well as reduce scar formation.

    View details for PubMedID 14528455

  • Injury to the dorsal sensory branch of the ulnar nerve in the Arthroscopic repair of ulnar-sided triangular fibrocartilage tears using an inside-out technique: A cadaver study JOURNAL OF HAND SURGERY-AMERICAN VOLUME McAdams, T. R., Hentz, V. R. 2002; 27A (5): 840-844

    Abstract

    This anatomic study of the commonly described inside-out Tuohy needle technique was performed to better define the course of needle passage relative to the anatomic structures in this region including the dorsal sensory branch of the ulnar nerve (DBUN) and extensor carpi ulnaris (ECU) tendon. Ten fresh-frozen cadaver specimens had arthroscopic-guided passage of a Tuohy needle through the triangular fibrocartilage (TFC). Dissection of the ulnar side of the wrist was performed and various measurements were recorded. The average minimum distance between suture A (the suture closest to the nerve) and the DBUN was 1.9 mm. The average minimum distance between suture B and the DBUN was 2.7 mm. The distance between the 2 sutures at the level of the capsule averaged 6.2 mm. The distance between the DBUN and the ECU averaged 7.2 mm. In 5 of 10 specimens the sutures exited on opposite sides of the DBUN. The DBUN is variable in its course but in every case it passes in close proximity to the sutures that exit the ulnar side of the wrist in arthroscopic repair of ulnar-sided TFC tears.

    View details for DOI 10.1053/jhsu.2002.34370

    View details for Web of Science ID 000178152400012

  • Surgical strategy: matching the patient with the procedure HAND CLINICS Hentz, N. R. 2002; 18 (3): 503-?

    Abstract

    The general indications, timing, and choice of procedure can be determined by asking and answering the following questions appropriately: 1. Has the patient achieved neurologic, emotional, and social stability? 2. What is the patient's current level of motor and sensory resources and function? The number and strength of muscles remaining under good voluntary control are the most important variables. 3. Are the patient's expectations realistic? 4. Does the patient possess the necessary intelligence and motivation? Some procedures, such as arthrodesis of a specific joint, require little motivation to succeed; however, a complex set of muscle-tendon transfers requires a great deal of motor reeducation for the patient to achieve an optimal result. 5. Does the patient have the necessary time to invest in achieving a good result? The patient must be able to set aside the time necessary for postoperative immobilization in a cast or splint and for therapy and reeducation. 6. Are the necessary support services and personnel available and committed? 7. Have all preoperative obstacles to success been considered and has a plan developed to overcome any remaining obstacles? 8. Does the patient understand the potential complications and benefits? 9. Can the patient and professional team tolerate a complication, failure, or suboptimal result? Both the medical staff and the patient must be prepared for complications that may lead to a suboptimal outcome or frank failure. 10. Are the patient's current health and well-being ideal? 11. Is the surgical plan consistent with the patient's physical resources, goals, and expectations? 12. Does an alternate plan exist? 13. Does the surgeon understand the scope of the complications and how to salvage an acceptable result should a complication occur?

    View details for Web of Science ID 000179737000014

    View details for PubMedID 12474600

  • Reconstruction of the hand in Apert syndrome: A simplified approach PLASTIC AND RECONSTRUCTIVE SURGERY Chang, J., Danton, T. K., Ladd, A. L., Hentz, V. R. 2002; 109 (2): 465-470

    Abstract

    Children born with Apert acrocephalosyndactyly pose great challenges to the pediatric hand surgeon. Reconstructive dilemmas consist of shortened, deviated phalanges and extensive skin deficits following syndactyly release. We present a 10-year review of patients with Apert acrocephalosyndactyly who were treated with a simplified surgical approach. Between 1986 and 1996, 10 patients with Apert syndrome underwent reconstructive surgery of their hands. The overall strategy involved early bilateral separation of syndactylous border digits at 1 year of age, followed by sequential unilateral middle syndactyly mass separation with thumb osteotomy and bone grafting as needed. In these 10 patients, a total of 53 web spaces were released, 49 of which involved osteotomies for complex syndactyly. Only local flaps and full-thickness skin grafts from the groin were used in all cases to achieve soft-tissue coverage. To date, seven of the 53 web spaces have needed revision (revision rate, 13 percent). Eleven thumb osteotomies (nine opening wedge and two closing wedge) were performed. Bone grafts from the proximal ulna or from other digits were used in all cases. To date, none of these thumb osteotomies have needed revision. This early, simplified approach to the complex hand anomalies of Apert acrocephalosyndactyly has been successful in achieving low revision rates and excellent functional outcomes as measured by gross grasp and pinch and by patient and parent satisfaction.

    View details for Web of Science ID 000173678000008

    View details for PubMedID 11818821

  • Gene expression of transforming growth factor beta isoforms in interposition nerve grafting JOURNAL OF HAND SURGERY-AMERICAN VOLUME Karanas, Y. L., Bogdan, M. A., Lineaweaver, W. C., Hentz, V. R., Longaker, M. T., Chang, J. 2001; 26A (6): 1082-1087

    Abstract

    Scar production and neuroma formation at nerve graft coaptation sites may limit axonal regeneration and impair functional outcome. Transforming growth factor beta (TGF-beta) is a family of growth factors that is involved in scar formation, wound healing, and nerve regeneration. Fifteen adult Sprague-Dawley rats underwent autogenous nerve grafting. The nerve grafts were analyzed by in situ hybridization to determine the temporal and spatial expression of TGF-beta1 and TGF-beta3 messenger RNA (mRNA). The grafted nerves showed increased expression of TGF-beta1 and TGF-beta3 mRNA in the nerve and the surrounding connective tissue during the first postoperative week. These data suggest that modulation of TGF-beta levels in the first postoperative week may be effective in helping to control scar formation and improve nerve regeneration.

    View details for Web of Science ID 000172412500014

  • Surgeon-patient barrier efficiency monitored with an electronic device in three surgical settings WORLD JOURNAL OF SURGERY Hentz, V. R., Stephanides, M., Boraldi, A., Tessari, R., Isani, R., Cadossi, R., Biscione, R., Massari, L., Traina, G. 2001; 25 (9): 1101-1108

    Abstract

    Blood-borne viral pathogens are an occupational threat to health care workers (HCWs), particularly those in the operating room. A major risk is posed by accidental penetrating injury, but skin contamination with body fluids from an infected patient, with prolonged intimate cutaneous contact, is a frequent occurrence during surgery, carrying further risk of transdermal infection. We have monitored barrier failure in three surgical settings (microsurgery, orthopedic surgery, general surgery) by means of an electronic surveillance device. A total of 111 surgical procedures were monitored: 67 microsurgeries, 22 orthopedic surgeries, and 22 general surgeries. Of the 278 electronic alarms signaling barrier failure, 44 (15.8%) were associated with glove perforation, 39 of which (88.6%) were not perceived by the operator. In 16 of those, the skin was visibly stained with the patient's blood. Altogether, 76 of the alarms (27.3%) were consequent to contacts caused by soaked gowns/sleeves, and 121 (43.5%) were attributed to hydration of latex porosities; 37 alarms (13.4%) were unexplained false positives. On only one occasion did a surgeon observe blood stains on his hands without a previous alarm; this event was classified as a device failure due to incorrect wiring. Double-gloving offered satisfactory protection against skin contamination during microsurgery but not during orthopedic surgery. The data presented here indicate that electronic monitoring of the surgical barrier enables prompt detection of barrier failure, especially at the level of the gloves, thereby limiting skin contamination with patients' body fluids during surgery.

    View details for Web of Science ID 000170934500001

    View details for PubMedID 11571942

  • Improvement of schwann cell attachment and proliferation on modified hyaluronic acid strands by polylysine TISSUE ENGINEERING Hu, M., Sabelman, E. E., Tsai, C., Tan, J., Hentz, V. R. 2000; 6 (6): 585-593

    Abstract

    Hyaluronic acid (HyA) has the intrinsic ability to promote cell proliferation and reduce scar formation. However, the clinical use of HyA has so far been limited because of its water solubility and nonadhesive characteristics. Increasing interest in HyA as a clinically useful biomaterial has prompted our study of altering HyA's physical properties to render it a potential component of nerve grafts. In this study, strands of HyA were cross-linked by glutaraldehyde (Glut), coated with polylysine, and then inoculated with Schwann cells (SCs). Results in vivo and in vitro demonstrated that cross-linked HyA strands were water insoluble and thus less biodegradable. Poly-D-lysine-resurfaced strands showed significant SC attachment of 350-400 cells/mm(2), compared to uncoated controls (0-10 cells/mm(2), p < 0.01). Fibroblast control groups showed an attachment of 40-100 cells/mm(2) on coated strands. Immunostaining for proliferating cells showed SCs as and fibroblasts as +. Cells neither adhered to nor proliferated on the modified HyA strands that were not resurfaced. The results suggest that polylysine promotes SC attachment and proliferation to glutaraldehyde-cross-linked HyA strands, the product being a three-dimensional composite with low solubility that may have potential application in nerve grafts.

    View details for Web of Science ID 000165511500001

    View details for PubMedID 11103080

  • Hand and wrist injuries in young athletes HAND CLINICS Le, T. B., Hentz, V. R. 2000; 16 (4): 597-?

    Abstract

    Successful treatments of musculoskeletal injuries in the pediatric population demand a thorough understanding of the basic anatomy and its biomechanics, and the physiology of growth and development of the immature skeleton. In addition, good treatment outcomes rely on the treating physician being an effective teacher to the young athlete and the patient's parents, coaches, and trainers. At the same time, the physician must be a good student in learning the nature of the patient's sports and each patient's athletic ability and aspirations. Most pediatric hand and wrist injuries can be treated nonoperatively with proper immobilization techniques and activity modification, but cases requiring surgical intervention must be recognized promptly to avoid long-term complications.

    View details for Web of Science ID 000165582700011

    View details for PubMedID 11117050

  • Presidential address: How shall we teach? How shall we learn? Educating hand surgeons in the new millennium. journal of hand surgery Hentz, V. R. 2000; 25 (4): 608-615

    View details for PubMedID 10913200

  • Polypeptide resurfacing method improves fibroblast's adhesion to hyaluronan strands JOURNAL OF BIOMEDICAL MATERIALS RESEARCH Hu, M., Sabelman, E. E., Lai, S., Timek, E. K., Zhang, F., Hentz, V. R., Lineaweaver, W. C. 1999; 47 (1): 79-84

    Abstract

    Hyaluronic acid (hyaluronan, HyA) is a matrix component that takes part in cell adhesion and growth in normal and repaired tissues. Since it is soluble in water, HyA has been of limited use in tissue engineering of artificial matrices. Recent studies demonstrate that polypeptides have the twin advantages of reducing solubility of HyA and improving cellular attachment via cell surface adhesion molecule receptors. This paper describes a new approach of using a polypeptide resurfacing method to enhance the attachment of cells to HyA strands. HyA strands were crosslinked by glutaraldehyde and then resurfaced with poly-D-lysine, poly-L-lysine, glycine, or glutamine. After inoculation with fibroblasts in vitro, modified HyA was evaluated with histological and immunohistochemical staining methods for cell adhesion and proliferation. Modified HyA with fibroblast cells also were implanted in vivo. The results show that (1) both polylysines enhanced fibroblast adhesion to crosslinked HyA strands; (2) HyA strands were able to be crosslinked well by 3 days of treatment in glutaraldehyde, and as a biomaterial they could resist biodegradation; (3) modified HyA has good biocompatibility, both in vitro and in vivo. The results demonstrate that HyA material resurfaced by polypeptides has positive advantages for cellular adhesion. Resurfaced HyA has much potential as an improved biomaterial for clinical usage.

    View details for Web of Science ID 000081599800011

    View details for PubMedID 10400884

  • Enhancement of axon growth by detergent-extracted nerve grafts TRANSPLANTATION Dumont, C. E., Hentz, V. R. 1997; 63 (9): 1210-1215

    Abstract

    The immunogenicity of nerve allografts is responsible for their rejection. We have developed a method for preparing cell-free nerve grafts using lysophosphatidylcholine to remove cells, axons, and myelin sheaths.The remaining intact nerve extracellular matrix is the extracted nerve graft (eNG). Cultured neonatal Schwann cells were micro-injected into the eNG to form recellularized nerve grafts (rNG). eNG, rNG, and normal isografts (15 mm long) were implanted in the peroneal nerves of F-344 rats. Ten rats were given an eNG on the right, and an isograft on the left. Ten rats were given an rNG on the right, and a sham operation on the left. Sham operation was used as the control and the isograft was used as the benchmark procedure. Walking track analysis was performed every 15 days after surgery to determine the peroneal functional index. Morphometric analysis of the distal peroneal nerve and extensor digitorum muscle weight were analyzed 3 months after surgery.The three types of grafted legs had the classical effect observed after peripheral nerve repair, with decreased functional ability, decreased target muscle weight, fewer large nerve fibers, and more small nerve fibers. Isografts, eNG, and rNG all had similar patterns of peroneal functional index improvement after implantation. The extensor digitorum longus muscle weight and axon counts for the three types of graft were not statistically different. Hence, eNG and rNG can enhance nerve regeneration in the same way as isografts. The host Schwann cells that invaded the implanted eNG probably acted in the same fashion as the cultured Schwann cells injected into the rNG and the resident cells of isografts.The great permeability of the longitudinally oriented matrix of eNG to cells is, therefore, a major advantage over the reported poor permeability of freeze-thawed nerve grafts.

    View details for Web of Science ID A1997WZ23100004

    View details for PubMedID 9158011

  • A composite nerve graft system: Extracted rat peripheral nerve injected with cultured Schwann cells MUSCLE & NERVE Dumont, C. E., Bolin, L. M., Hentz, V. R. 1996; 19 (1): 97-99

    View details for Web of Science ID A1996TM00100017

    View details for PubMedID 8538678

  • Surgical reconstruction in tetraplegia. Procedure and Hand Surgery. - Vincent R. Hentz, Amy Ladd 1996
  • The role of microsurgical flap procedure in a medical center. Advances in Plastic and Reconstructive Surgery. 2 - Lineaweaver WC, Hui K, Ramos D, Hentz VR, Norris M, Steinberg G 1995
  • Thumb reconstruction and pollicization by conventional techniques. Mastery of Plastic and Reconstructive Surgery. - Vincent R. Hentz 1994
  • EXTENSOR DIGITI-MINIMI TENDON TRANSFER TO PREVENT RECURRENT ULNAR DRIFT PLASTIC AND RECONSTRUCTIVE SURGERY Pearl, R. M., Hentz, V. R. 1993; 92 (3): 507-510

    Abstract

    Thirty percent of patients with rheumatoid arthritis develop ulnar drift. Although numerous operations have been described, recurrence of the deformity is frequent. We recommend use of the extensor digiti minimi tendon transfer to prevent recurrent ulnar deviation. The tendon insertion is moved from a dorsal location to a dorsal-radial position. In this new location, the tendon produces both extension and radial deviation. Moreover, this transfer is maximally effective in extension when ulnar drift is greatest. We have used this transfer 28 times during the past 6 years. In evaluating patients more than 1 year after surgery, metacarpal phalangeal joint extension averaged 52 degrees and there was no evidence of recurrent ulnar drift of the little finger. The only problem was slight hyperextension of less than 5 degrees in approximately half of the patients. However, in no patient was this functionally a problem. We recommend the use of this tendon transfer in all patients with ulnar drift undergoing metacarpal phalangeal joint replacement for rheumatoid arthritis.

    View details for Web of Science ID A1993LR60800020

    View details for PubMedID 8341752

  • The nerve gap dilemma: a comparison of nerves repaired end to end under tension with nerve grafts in a primate model. journal of hand surgery Hentz, V. R., Rosen, J. M., Xiao, S. J., McGill, K. C., Abraham, G. 1993; 18 (3): 417-425

    Abstract

    The objective of this study was to compare, in a clinically relevant primate model, axon regeneration after epineurial repair under tension (15 mm gap) with interfascicular nerve grafts with the use of either standard microsuture techniques or a new interfascicular nerve graft technique termed fascicular tubulization that uses a hypoantigenic collagen membrane formed into a tube to approximate nerve ends. Electrophysiologic analysis demonstrated that the percentage of proximal axons that conducted across the repair site was greater in those nerves repaired under tension with epineurially placed sutures than in either of the tensionless repairs involving interfascicular graft techniques. The mean diameters of the regenerated axons repaired under tension with epineurial sutures were greater than those of the nerves repaired with interfascicular grafts, although the difference was not statistically significant. Interfascicular nerve grafting with tubulization using the current collagen tube resulted in regeneration equal to the sutured interfascicular nerve grafts. For modest defects (perhaps up to 3 to 4 cm in the adult), it seems advantageous to accept the modest tension associated with an epineurial repair rather than to use an autograft (or artificial graft) to achieve a tension-free repair.

    View details for PubMedID 8515008

  • Reconstruction of brachial plexus injuries. Operative Hand Surgery. - Vincent R. Hentz 1993
  • Rehabilitation and surgical reconstruction of the upper limb in tetraplegia: an update. journal of hand surgery Hentz, V. R., House, J., McDowell, C., Moberg, E. 1992; 17 (5): 964-967

    View details for PubMedID 1401816

  • A PRACTICAL GUIDE TO INTERNATIONAL LEECH TRANSPORTATION ANNALS OF PLASTIC SURGERY Stephanides, M., Rosen, J. M., Hentz, V. R., SAMUELS, S. I. 1992; 29 (3): 282-283

    View details for Web of Science ID A1992JL75400018

    View details for PubMedID 1524383

  • BRACHIAL-PLEXUS MICROSURGERY IN CHILDREN MICROSURGERY Hentz, V. R., Meyer, R. D. 1991; 12 (3): 175-185

    Abstract

    From this review, the following points have emerged: 1. The typical obstetrical palsy is a traumatic lesion caused by forced lowering of the shoulder during delivery. 2. While the lesion may affect all the roots, the upper roots are usually ruptured, whereas the lower roots (if involved) are always avulsed. 3. Spontaneous recovery is possible, but its quality depends on how early recovery of previously paralyzed muscles begins. If the biceps have not started to recover by 3 months, the final result will be poor. It is at this time interval that a surgical decision should be made. 4. Surgical repair is always possible, usually by grafting, though repair can be difficult if significant numbers of avulsions have occurred. 5. The results of surgical reconstruction are better than are the results of spontaneous evolution, at least in those patients who reach the age of 3 months without evidence of recovery of the biceps. For example, more than half of the patients recover a nearly normal shoulder after grafting C5, C6 lesions in Gilbert's series, whereas in the same control population of patients, none achieved this result spontaneously. 6. Palliative treatment of the sequelae of birth palsies is difficult, and the results obtained are rarely totally satisfactory. It is for these reasons that the initial surgical intervention should be on the plexus itself in those instances meeting the criteria established above. It is important to make this decision as quickly as possible before neuroplasticity is diminished and joint contractions have occurred.

    View details for Web of Science ID A1991FL70700006

    View details for PubMedID 1865811

  • Cloward technique for obtaining iliac crest bone graft in hand surgery. journal of hand surgery BRODY, G. A., Hentz, V. R. 1990; 15 (1): 181-183

    View details for PubMedID 2299162

  • DIGIT REPLANTATION APPLYING THE LEECH HIRUDO-MEDICINALIS CLINICAL ORTHOPAEDICS AND RELATED RESEARCH BRODY, G. A., Maloney, W. J., Hentz, V. R. 1989: 133-137

    Abstract

    Digits that were formerly assessed as nonreplantable may now be replanted with the help of the leech Hirudo medicinalis. The early experience with a series of patients who had relative contraindications for replantation is reported. In each case, venous repair was either marginal or technically impossible. Postoperative venous congestion developed following replantation and was treated with the application of medicinal leeches. Patient acceptance was high, and no infections developed. No patient required transfusion. The authors conclude that the use of medicinal leeches shows promise as a safe and effective method of providing temporary venous drainage in replanted digits.

    View details for Web of Science ID A1989AJ74100020

    View details for PubMedID 2752613

  • FASCICULAR TUBULIZATION - A COMPARISON OF EXPERIMENTAL NERVE REPAIR TECHNIQUES IN THE CAT ANNALS OF PLASTIC SURGERY Rosen, J. M., Pham, H. N., Hentz, V. R. 1989; 22 (6): 467-478

    Abstract

    Peripheral nerve repair remains one of the most difficult problems in hand surgery; the results of conventional epineurial and fascicular suture repair are a major limitation to the rehabilitation of the patient. The aim of this study was to evaluate a tubulization technique of nerve repair by wrapping a membrane of hypoantigenic collagen around the nerve at the fascicular level. Cat ulnar and median nerves were used as a multifascicular nerve model. Thirty-eight animals were studied. Ten animals were included in long-term studies comparing fascicular tubulization to either epineurial suture or fascicular suture nerve repair. Histologically, the tube repairs demonstrated improved organization at the repair site compared with either suture technique. Tube repair is not significantly different statistically by quantitative histological and physiological evaluation methods from epineurial suture or fascicular suture repairs. Further studies in more clinically applicable animal models are required before this technique can be considered as an alternative to present clinical nerve suture techniques.

    View details for Web of Science ID A1989AC14600002

    View details for PubMedID 2751220

  • EFFECT OF LOW-FREQUENCY LOW-ENERGY PULSING ELECTROMAGNETIC-FIELD (PEMF) ON X-RAY-IRRADIATED MICE EXPERIMENTAL HEMATOLOGY Cadossi, R., Hentz, V. R., Kipp, J., EIVERSON, R., Ceccherelli, G., Zucchini, P., Emilia, G., Torelli, G., Franceschi, C., Cossarizza, A. 1989; 17 (2): 88-95

    Abstract

    C3H/Km flora-defined mice were used to investigate the effect of exposure to pulsing electromagnetic field (PEMF) after total body x-ray irradiation. Prolonged exposure to PEMF had no effect on normal nonirradiated mice. When mice irradiated with different doses of x-ray (8.5 Gy, 6.8 Gy, and 6.3 Gy) were exposed to PEMF 24 h a day, we observed a more rapid decline in white blood cells (WBC) in the peripheral blood of mice exposed to PEMF at all the x-ray dosages used. No effect of exposure to PEMF was observed on the survival of the mice irradiated with 6.3 Gy and 8.5 Gy; in mice irradiated with 6.8 Gy, 2 out of 12 survived when exposed to PEMF as compared to 10 out of 12 control mice that were irradiated only. At day 4 after irradiation autoradiographic studies performed on bone marrow and spleen of 8.5-Gy-irradiated mice showed no difference between controls and mice exposed to PEMF, whereas on 6.8-Gy mice the bone marrow labeling index was lower in mice exposed to PEMF. In mice irradiated to 6.3 Gy we observed that the recovery of WBC in the peripheral blood was slowed in mice exposed to PEMF and their body weight was significantly lower than in control mice that were irradiated only. The spleen and bone marrow of the mice irradiated to 6.3 Gy and sacrificed at days 4, 14, 20, and 25 after irradiation were analyzed by autoradiography to evaluate the labeling index. Half of the spleens from mice sacrificed at day 25 after irradiation were used to evaluate the RNA content. Autoradiography showed that in the spleen and bone marrow of control mice, there were more cells labeled with [3H]thymidine at days 4 and 14 and less at days 20 and 25 after irradiation in comparison with mice irradiated and exposed to PEMF. The Northern blot analysis of histone H3 and p53 protein RNAs extracted from the spleens at day 25 after irradiation showed a slight increase in cycling cells among spleens of mice exposed to PEMF. We suggest that the exposure to PEMF immediately after x-ray irradiation results in increased damage.

    View details for Web of Science ID A1989T025300004

    View details for PubMedID 2643520

  • AN APPROACH TO MANDIBULAR RECONSTRUCTION ANNALS OF PLASTIC SURGERY Pearl, R. M., Lepore, V., Hentz, V. R., SARIG, A. 1988; 21 (5): 401-417

    Abstract

    Mandibular reconstruction requires the restitution of both form and function. Proper preoperative planning, vascularized bone grafts, rigid fixation, flexibility of donor site choices, and restoration of labial, buccal, and lingual sulci lead to optimal reconstruction. We have used this approach in 38 patients; bony survival resulted in 37 and primary union in 35. A main limiting factor exists with individuals who have lost extensive amounts of soft tissue and muscle at the time of tumor resection or trauma. Only by attention to details in the preoperative, intraoperative, and postoperative phases can the best functional and aesthetic results be achieved.

    View details for Web of Science ID A1988Q973500002

    View details for PubMedID 3069032

  • SURGICAL RECONSTRUCTION IN TETRAPLEGIA HAND CLINICS Hentz, V. R., Hamlin, C., KEOSHIAN, L. A. 1988; 4 (4): 601-607

    Abstract

    The authors reviewed their 10 years of combined experience in the surgical reconstruction of the upper extremities in 170 quadriplegic patients from two spinal cord treatment centers. The authors' current recommendations regarding patient selection are presented, refinements in previously published surgical techniques are defined, and the principles of postoperative care are discussed.

    View details for Web of Science ID A1988R233000006

    View details for PubMedID 3073162

  • REPETITIVE TRAUMA AND NERVE COMPRESSION ORTHOPEDIC CLINICS OF NORTH AMERICA Carragee, E. J., Hentz, V. R. 1988; 19 (1): 157-164

    Abstract

    Repetitive movement of the upper extremity, whether recreational or occupational, may result in various neuropathies, the prototype of which is the median nerve neuropathic in the carpal canal. The pathophysiology of this process is incompletely understood but likely involves both mechanical and ischemic features. Experimentally increased pressures within the carpal canal produced reproducible progressive neuropathy. Changes in vibratory (threshold-type) sensibility appears to be more sensitive than two-point (innervation density-type) sensibility. The specific occupational etiologies of carpal neuropathy are obscured by methodologic and sociological difficulties, but clearly some occupations have high incidences of CTS. History and physical examination are usually sufficient for the diagnosis, but diagnostic assistance when required is available through electrophysiological testing, CT scanning, and possibly MRI. Each of these tests has limitations in both sensitivity and specificity. Treatment by usual conservative means should be combined with rest from possible provocative activities. Surgical release of the carpal canal is helpful in patients failing conservative therapy. Occupational modifications are important in both treatment and prevention of median neuropathy due to repetitive trauma.

    View details for Web of Science ID A1988L630200015

    View details for PubMedID 3275923

  • THE RESULTS OF MICRONEUROSURGICAL RECONSTRUCTION IN COMPLETE BRACHIAL-PLEXUS PALSY - ASSESSING OUTCOME AND PREDICTING RESULTS ORTHOPEDIC CLINICS OF NORTH AMERICA Hentz, V. R., NARAKAS, A. 1988; 19 (1): 107-114

    Abstract

    The outcome of microsurgical reconstruction in 114 adult patients presenting with complete traumatic brachial plexus palsy was analyzed. The authors examined the effects of age, time since injury, operative findings, and the techniques of reconstruction on the level of muscle recovery. Statistical and analytic computer programs were used in an attempt to determine what factors most influenced recovery.

    View details for Web of Science ID A1988L630200010

    View details for PubMedID 3336570

  • THE RADIAL FOREARM FLAP - A VERSATILE SOURCE OF COMPOSITE TISSUE ANNALS OF PLASTIC SURGERY Hentz, V. R., Pearl, R. M., Grossman, J. A., Wood, M. B., Cooney, W. P. 1987; 19 (6): 485-498

    Abstract

    The radiovolar area of the forearm constitutes a versatile source of composite tissues for pedicle flap reconstruction of the hand and free-flap reconstruction for many areas of the body. The skin is thin and relatively hairless, and the vascular pedicle is long and of large caliber. The flap can be harvested to contain vascularized tendons and bone. The skin can be reliably reinnervated. The principal disadvantage, that this is a conspicuous donor site, has not been a source of concern for our patients. Nineteen of the 20 (95%) free flaps survived completely.

    View details for Web of Science ID A1987L530700001

    View details for PubMedID 3439761

  • Application of free tissue transfers to the foot. Journal of reconstructive microsurgery Hentz, V. R., Pearl, R. M. 1987; 3 (4): 309-320

    Abstract

    During the past five years we have used three sources of free tissue transfers in 26 patients to reconstruct defects of the ankle and dorsum, hind, mid- and forefoot, defects poorly or unamenable to traditional reconstructive methods. These included free muscle transfers covered with a skin graft, temporoparietal fascia also covered with a graft, and radial forearm skin or fascia. In addition, six complex defects were reconstructed with composite tissue free transfers, usually tendinocutaneous flaps. There was one partial flap loss. All were successful in both healing the defect and in providing functional restoration, except in the forefoot. From an analysis of these cases, we have developed indications for various transfers based on the functional needs of the area involved and donor site requirements.

    View details for PubMedID 2888887

  • IMAGING STUDIES OF THE CADAVER HAND USING TRANSMISSION ULTRASOUND SKELETAL RADIOLOGY Hentz, V. R., Green, P. S., Arditi, M. 1987; 16 (6): 474-480

    Abstract

    Ultrasonic transmission imaging has already demonstrated potential for evaluating structures in the hand. In this study, a cadaver hand was imaged using a transmission scanner with improved imaging capability. The hand was then frozen and serially sectioned and comparisons were made between the sectional anatomy and the corresponding image. Bone (in silhouette), muscle, cartilage, and tendon were visualized with high resolution.

    View details for Web of Science ID A1987J669100008

    View details for PubMedID 3310247

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