Dupuytren's Contracture Recurrence and Treatment Following Collagenase Clostridium Histolyticum Injection: A Longitudinal Assessment in a Veteran Population.

INTRODUCTION: Dupuytren's contracture is a connective tissue disease characterized by an abnormal proliferation of collagen in the palm and fingers, which leads to a decline in hand function because of progressive joint flexion. In addition to surgical and percutaneous interventions, collagenase clostridium histolyticum (CCH, trade name Xiaflex) is an intralesional enzymatic treatment for adults with palpable cords. The objectives of this study are to evaluate factors predictive of recurrence following treatment with CCH and to review the outcomes of repeat treatments with CCH for recurrent contracture. MATERIALS AND METHODS: An institutional review board-approved retrospective chart review was conducted for patients between 2010 and 2017 who received CCH injections for Dupuytren's contracture at a Veterans Affairs hospital. Demographics, comorbidities, affected finger and joint, pre/posttreatment contracture, time to recurrence, and treatment of recurrence were recorded. Successful treatment was defined as contracture ≤5° following CCH, and improvement was defined as ≥20° reduction from baseline contracture. Study cohorts were followed after their secondary treatment, and time to recurrence was recorded and plotted using a Kaplan-Meier curve. A Cox proportional hazards model was used to compare treatment group risk factors for recurrence with a P-value less than .05 defined as statistical significance. RESULTS: Of 174 injections performed for the correction of flexion deformities in 109 patients, 70% (121) were successfully treated with CCH, and an additional 20% (35) had improvement. There was a recurrence of contractures in 43 joints (25%). Of these, 16 contractures were treated with repeat CCH, whereas another 16 underwent limited fasciectomy. In total, 75% (12 of 16) of the repeat CCH group and 75% of the fasciectomy group were successfully treated. Pre-injection contracture of ≥25° was found to be predictive of recurrence (P < .05). CONCLUSIONS: Initial treatment of contracture with CCH had a 70% success rate with 25% recurrence during the study period. Compared with limited fasciectomy, CCH had decreased efficacy. Based on the findings of this study, we believe that the treatment of primary and/or recurrent Dupuytren's contracture with CCH is a safe and less invasive alternative to fasciectomy in the era of telemedicine. CCH treatment requires no suture removal, which allows the ability to assess motion virtually, and the potential consequences of CCH treatment such as skin tears can be assessed and managed conservatively. In the veteran and active duty population, CCH can facilitate faster recovery and return to service. Strengths of this study include a large series of veteran populations with longitudinal follow-up to determine treatment efficacy for primary Dupuytren's contracture and recurrence. Limitations include a smaller sample size compared to previous trials, a lack of standardized follow-up, and the retrospective nature of our study that prohibits randomization to compare outcomes between CCH treatment and fasciectomy efficacy over time. Directions for future research include stratification of patients by joint and specific digit involvement as well as comparison with percutaneous needle fasciotomy, another minimally invasive technique that could benefit the veteran population at increased risk for developing Dupuytren's disease.

Cutaneous Mucormycosis of the Upper Extremity: Case Reports Highlighting Rapid Diagnosis and Management.

ABSTRACT: Mucormycosis is a devastating fungal infection known for its angioinvasive spread and hematogenous dissemination, quickly resulting in multiorgan involvement and potentially fatal complications. Timely diagnosis is essential to facilitate early, aggressive debridement, yet the diagnosis remains difficult to obtain because of the need for culture and microscopy diagnosis. We provide case examples, which highlight diagnostic pearls and the multidisciplinary approach that are critical for improving local outcomes, preventing systemic spread, and reducing mortality.

Dermal Shift Umbilical Reconstruction: An Innovative and Simple Technique.

SUMMARY: Umbilical reconstruction is a procedure with widespread indications in the setting of congenital or postsurgical loss. Reconstruction of the umbilicus when no remnant of the natural umbilicus is present is also called neoumbilicoplasty. Numerous neoumbilicoplasty techniques have been published, including cartilage grafts, full-thickness skin grafts, and multiflap reconstruction. No consensus has been reached regarding an optimal technique, and many procedures involve complicated designs with small flaps that are difficult to reproduce or explain. The authors divide patients into three types depending on the thickness of the adipose layer of the abdomen. With appropriate patient selection and minor variations depending on patient type, the technique can be applied to all patients. The umbilicus is marked in the appropriate position. Local anesthesia is infiltrated, and the area beneath the skin is defatted. The dermis is then applied to the underlying fascia with a superior shift. The authors describe the technique and its variations and present one illustrative case with additional supplemental digital content. The authors have gone through a progression of techniques to find a simple surgical method yielding consistently reproducible results with minimal complexity, limited morbidity, and an aesthetic final outcome. The authors believe that the technique described here achieves those goals. It can be performed under local anesthetic and with a simple occlusive dressing so that the patient can go on with most of his or her daily activities. There is no scar to suggest a surgical procedure, and patients are extremely happy with the aesthetic outcomes.

Facial Aging: A Quantitative Analysis of Midface Volume Changes over 11 Years.

BACKGROUND: Anatomical studies have identified separate superficial and deep facial fat compartments, leading some to theorize that volume loss from the deep midface causes overlying superficial fat pseudoptosis. Unfortunately, a paucity of evidence exists regarding whether facial fat volume is truly lost with age and, if so, whether it is lost equally or differentially from the superficial and deep compartments. The aim of this study was to quantify volume changes occurring with age within the superficial, deep, and buccal fat compartments of the midface. METHODS: A retrospective longitudinal study was performed evaluating individuals aged 30 to 65 years who underwent facial computed tomography followed by facial computed tomography greater than or equal to 10 years later. Superficial midface, deep midface, and buccal fat volumes were quantified using Horos radiology software. RESULTS: Nineteen subjects met inclusion criteria. Mean total fat volume decreased significantly from 46.47 cc to 40.81 cc (p < 0.01). The mean superficial and deep fat volumes both decreased significantly from 26.10 cc to 23.15 cc (p < 0.01) and from 11.01 cc to 8.98 cc (p < 0.01), respectively. No significant difference was observed in buccal fat volume over time (9.36 cc to 8.68 cc; p = 0.04). Patients lost an average of 11.3 percent of their initial superficial fat volume and 18.4 percent of their initial deep fat volume. CONCLUSIONS: Significant volume loss was observed from both superficial and deep facial fat compartments over a mean 11.3 years. Patients lost a greater percentage of deep facial fat volume, providing support for the theory of pseudoptosis caused by deep midface fat loss.

Vascularized Olecranon Bone Graft: An Anatomical Study and Novel Technique.

PURPOSE: Autologous bone grafting is commonly used in reconstructive hand surgery. Various sources of nonvascularized autologous bone grafts have been described in the literature. However, in some situations, a vascularized bone graft may be needed. Popular vascularized bone grafts are taken from the distal radius, iliac crest, and medial femoral condyle. The purpose of this study was to examine the feasibility of harvesting a free vascularized bone flap from the proximal ulna. METHODS: Latex was injected via the brachial artery to facilitate visualization of perforators in 10 cadaveric specimens. Dissections were performed of the olecranon; all periosteal perforators were noted, and their lengths and diameters recorded. Corticocancellous bone flaps with their supplying pedicles were harvested. Three additional fresh specimens were injected with india ink via the pedicles to demonstrate perfusion of the harvested bone flap. RESULTS: Consistent vascular anatomy supplied the olecranon. A perforator from the posterior ulnar recurrent artery supplied the proximal ulna and olecranon, from which a vascularized bone flap can be harvested. Branches to the flexor carpi ulnaris muscle may allow chimeric flaps to be harvested. Average pedicle length was 5.8 cm and average pedicle diameter was 2.4 mm. India ink injection of the pedicles showed perfusion of the periosteum as well as intraosseous cancellous bone. CONCLUSIONS: A vascularized olecranon free flap can be harvested based on the posterior ulnar recurrent artery. Vascular anatomy is consistent and flap harvest is simple and straightforward in all cadaveric specimens. CLINICAL RELEVANCE: A vascularized olecranon free flap represents a potential new surgical option when vascular bone flap reconstruction is considered.

Anconeus Epitrochlearis Muscle Associated With Cubital Tunnel Syndrome: A Case Series.

Background: Cubital tunnel syndrome is a common compressive neuropathy of the upper extremity. The anconeus epitrochlearis muscle is an unusual but occasional contributor. We review our experience with this anomalous muscle in elbows with cubital tunnel syndrome. Methods: We retrospectively reviewed charts of 13 patients noted to have an anconeus epitrochlearis muscle associated with cubital tunnel syndrome. Results: Ten patients had unilateral ulnar neuropathy supported by nerve conduction studies. Three had bilateral cubital tunnel syndrome symptoms with 1 of those having normal nerve conduction studies for both elbows. Eight elbows were treated with myotomy of the anconeus epitrochlearis muscle and submuscular transposition of the ulnar nerve. The other 8 elbows were treated with myotomy of the anconeus epitrochlearis muscle and in situ decompression of the ulnar nerve only. All but 1 patient had either clinical resolution or improvement of symptoms at follow-up ranging from 2 weeks to 1 year after surgery. The 1 patient who had persistent symptoms had received myotomy and in situ decompression of the ulnar nerve only. Conclusions: An anomalous anconeus epitrochlearis occasionally results in compression of the ulnar nerve but is usually an incidental finding. Its contribution to compression neuropathy can be tested intraoperatively by passively ranging the elbow while observing the change in vector and tension of its muscle fibers over the ulnar nerve. Regardless of findings, we recommend myotomy of the muscle and in situ decompression of the ulnar nerve. Submuscular transposition of the ulnar nerve may be necessary if there is subluxation.

A Novel Surgical Technique for Resuspension of Digital Pulp Tissue after Degloving Injuries.

Adherence of pulp tissue to the underlying distal phalanx is required for fundamental actions including grip, proprioception, and fine motor skills. Disruption of the fibrous septa causes sliding between the distal phalanx and overlying soft tissues, hindering basic hand function. The authors present a novel surgical technique in which the fibrous pulp septa are resuspended to the distal phalanx with bone anchors and sclerosing agents after a closed degloving injury.

Distally Based Pedicled Flexor Carpi Ulnaris Muscle Flap: An Anatomical Study and Clinical Application.

BACKGROUND: Proximally based, pedicled flexor carpi ulnaris (FCU) muscle flap has been described previously for soft tissue coverage of the proximal forearm and elbow. No studies have been done on the distal muscular perforators and its use as a distally based flap. METHODS: Ten fresh-frozen cadaveric dissections were done. Specimens were injected with latex to facilitate identification of the perforators. Distal muscular perforators were dissected and distances of the pedicles from the distal wrist crease and ulnar styloid were measured and recorded. A clinical case is also presented where a distally based FCU muscle flap was used for coverage in a patient with median nerve neuroma. RESULTS: A distal muscular perforator and a second more proximal perforator were identified in all specimens. The average distance from the most distal muscular perforator to the ulnar styloid was 3.0 cm. The average distance to the wrist crease was 4.6 cm. The more proximal perforators had an average distance to the ulnar styloid and wrist crease of 7.3 cm and 8.8 cm, respectively. At 7 months post-op, the patient who underwent median nerve neurolysis and coverage with pedicled FCU flap had much improved sensation, with complete resolution of pain and tingling, and without any functional deficits. CONCLUSIONS: The use of a distally based FCU muscle flap is a good option for soft tissue coverage of the distal forearm, wrist, and hand. The distal muscular perforators from the ulnar artery exhibit a relatively consistent anatomy.

Repair of the musculocutaneous nerve using the vagus nerve as donor by helicoid end-to-side technique: an experimental study in rats.

Although several donor nerves can be chosen to repair avulsed brachial plexus nerve injury, available nerves are still limited. The purpose of this study is to validate whether the vagus nerve (VN) can be used as a donor. Eighteen Sprague-Dawley male rats were divided into three groups (n = 6). The right musculocutaneous nerve (McN) was transected with differing subsequent repair. (1) HS-VN group: a saphenous nerve (SN) graft-end was helicoidally wrapped round the VN side (epi-and perineurium was opened) with a 30 ° angle, distal SN end was coapted to the McN with end-to-end repair. (2) EE-PN group: a SN was interpositionally grafted between the transected phrenic nerve (PN) and the McN by end-to-end coaptation. (3) Sham control group: McN was transected and not repaired and postoperative vital signs were checked daily. At three months, electrophysiology, tetanic force, wet biceps muscle weight, and histology were evaluated. Every tested mean value in HS-VN group was significantly greater than the EE-PN or the sham control groups (p < 0.05 or p < 0.005). The mean recovery ratio of regenerated nerve fibers was 96% and, in HS-VN group, the mean recovery ratio of CMAP was 79%. No vital signs changed in any group. There was no statistical difference (p > 0.5) between the mean VN nerve-fiber numbers of the segments proximal (2237 ± 134) and distal (2150 ± 156) to the VN graft-attachment site. Histological analysis revealed no axon injury or intraneural scarring at any point along the VN. This study demonstrated that VN is a practical and reliable donor nerve for end-to-side nerve transfer. © 2017 Wiley Periodicals, Inc.

Pediatric Hereditary Angioedema as a Cause of Acute Compartment Syndrome of the Hand and Forearm: A Case Report.

BACKGROUND: Compartment syndrome of the upper extremity is a surgical emergency that, when left untreated, can have dire consequences. Its causes are numerous, one of which is the uncommon entity hereditary angioedema, an autosomal dominant disease resulting in edema in a variety of potential locations, including the extremities. This is only the second time hereditary angioedema has been mentioned in the literature as a cause of compartment syndrome. METHODS: We present a case of hereditary angioedema leading to hand and forearm compartment syndrome in a 13-year-old pediatric patient. Diagnosis of hereditary angioedema was made by our Rheumatology colleagues with physical exam and a thorough history, and confirmed by laboratory studies. RESULTS: Our patient presented with compartment syndrome of the hand and forearm and underwent hand and volar forearm fasciotomies. She was subsequently worked up for hereditary angioedema with laboratory results confirming the diagnosis. She was discharged after a 5-day hospitalization with prophylactic C1-inhibitor therapy. CONCLUSIONS: Hereditary angioedema is a rare but known cause of compartment syndrome of the upper extremity, and must be considered when patients present with compartment syndrome of unknown etiology. This disease can be diagnosed by laboratory studies and symptoms can be controlled with medical therapy.

Increasing Calcium Level Limits Schwann Cell Numbers In Vitro following Peripheral Nerve Injury.

Background After peripheral nerve injury, there is an increase in calcium concentration in the injured nerves. Our previous publications have shown that increase in calcium concentration correlated well with degree of nerve injury and that local infusion of calcitonin has a beneficial effect on nerve recovery. Schwann cells play a pivotal role in regeneration and recovery. We aim to examine cultured Schwann cell survivals in various concentrations of calcium-containing growth media and the effect of calcitonin in such media. Methods To establish baseline in postinjury state, crush injury was induced in male Sprague-Dawley rats' sciatic nerves. Extra- and intraneural calcium concentrations were measured. To study Schwann cell survival, uninjured sciatic nerve segment was harvested and cultured in media containing various amounts of calcium. To study the effect of calcitonin, nerve harvest and culture were done in four additional media: (1) normal control, (2) normal control with calcitonin, (3) high calcium medium, and (4) high calcium medium with calcitonin. Schwann cells were studied and analyzed under fluorescent conditions. Results With increasing calcium concentration, there was a significant decrease in the number of Schwann cells. For the experimental groups, in which calcitonin had been added to the growth medium, there were similar amounts of Schwann cells present in both high and low calcium-containing medium. Conclusion Schwann cells are sensitive to increasing calcium concentration. Calcitonin counteracts the detrimental effects of high calcium on Schwann cell survival. This can have significant future clinical implications for patients with peripheral nerve injuries.

Best time window for the use of calcium-modulating agents to improve functional recovery in injured peripheral nerves-An experiment in rats.

Peripheral nerve injury can have a devastating effect on daily life. Calcium concentrations in nerve fibers drastically increase after nerve injury, and this activates downstream processes leading to neuron death. Our previous studies showed that calcium-modulating agents decrease calcium accumulation, which aids in regeneration of injured peripheral nerves; however, the optimal therapeutic window for this application has not yet been identified. In this study, we show that calcium clearance after nerve injury is positively correlated with functional recovery in rats suffering from a crushed sciatic nerve injury. After the nerve injury, calcium accumulation increased. Peak volume is from 2 to 8 weeks post injury; calcium accumulation then gradually decreased over the following 24-week period. The compound muscle action potential (CMAP) measurement from the extensor digitorum longus muscle recovered to nearly normal levels in 24 weeks. Simultaneously, real-time polymerase chain reaction results showed that upregulation of calcium-ATPase (a membrane protein that transports calcium out of nerve fibers) mRNA peaked at 12 weeks. These results suggest that without intervention, the peak in calcium-ATPase mRNA expression in the injured nerve occurs after the peak in calcium accumulation, and CMAP recovery continues beyond 24 weeks. Immediately using calcium-modulating agents after crushed nerve injury improved functional recovery. These studies suggest that a crucial time frame in which to initiate effective clinical approaches to accelerate calcium clearance and nerve regeneration would be prior to 2 weeks post injury. © 2017 Wiley Periodicals, Inc.

Effect of calcitonin on cultured schwann cells.

INTRODUCTION: After nerve injury, calcium concentrations in intranerve fibers quickly increase. We have shown that functional recovery of injured nerves correlates with calcium absorption. A slight increase in calcium reduces the number of Schwann cells present. Calcitonin therapy greatly improves regeneration by accelerating calcium absorption. We examined the effect of adding calcitonin to higher concentration calcium media on cultured Schwann cells. METHODS: The cells, isolated from intact sciatic nerves, were cultured with normal or higher concentration calcium media with or without calcitonin. Schwann cells were incubated with anti-S-100, goat-anti-mouse, and propidium iodide and then viewed through fluorescent light and phase-contrast microscopy for observation and analysis. RESULTS: The cells in each calcitonin-containing medium showed many Schwann cells, however, the cells in the higher concentration calcium media showed fewer and more defective Schwann cells. CONCLUSION: These results show that calcitonin protects against the harmful effects of excessive calcium encountered in peripheral nerve injury. Muscle Nerve 56: 768-772, 2017.

Hyoid Suspension Neck Lift.

BACKGROUND: The shape of the deep cervical structures is the shape of an aesthetic neck. With age, changes can obstruct visualization of that shape. Achieving a youthful contour requires removal of excess skin and fat but also control of the platysma to allow skin to redrape like a blanket over an underlying framework. The authors' technique makes the platysma part of the deep cervical structures whose shape underlies an attractive neck and allows the skin to redrape to that contour. METHODS: To make the platysma conform closely to the deep cervical structures and allow the skin to show that new form, the authors developed a procedure that includes removal of excess fat, attaching the platysma to the hyoid fascia, approximating the edges of the platysma above and below that suture, and wide undermining of skin to allow it to re-drape naturally over those deeper structures. RESULTS: Over 7 years, 110 patients underwent aesthetic facial surgery that included hyoid suspension of the platysma. One patient had recurrence of platysmal bands after failure of the key suture. Complications included hematoma in three patients and submental seromas in three patients, but no permanent nerve injury, no skin loss from vascular compromise, no reported changes in vocal resonance, and no complaints of difficulty swallowing. CONCLUSIONS: This method allows the skin to redrape over a youthful framework and produces reliable aesthetic and long lasting results. It is a simple, reproducible, teachable technique that enables surgeons to achieve results previously difficult to obtain in a single operation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Early Axonal Area Measurement Predicts Early Nerve Regeneration Outcomes.

BACKGROUND: Study of peripheral nerve injury and regeneration in laboratory animals can be time consuming and expensive. This study determines if it is possible to reduce time and cost for a peripheral nerve regeneration study. PURPOSE: The purpose of this study was to determine if nerve axonal area (NXA) or nerve fiber counting (NFC) correlates with compound muscle action potential (CMAP) recovery which is known to predict functional muscular recovery in the early stage of nerve regeneration. METHODS: In this study, six rats had a crush injury of the sciatic nerve without treatment. These rats were evaluated at 4 weeks of recovery with the following assessments: CMAP readings from the extensor digitorum longus, NXA measurement, and NFC. RESULTS: NXA correlated with CMAP; NFC did not correlate with CMAP. CONCLUSION: NFC is not a reliable method for predicting muscular recovery in the early stages. NXA is a dependable assessment for muscular recovery in the early stages of nerve regeneration. Using NXA measurement can predict later electrophysiological and functional recovery. Using NXA with CMAP measurement for nerve injury, repair, and treatment in the animal study can save cost and time.

Cumulative Brain Injury from Motor Vehicle-Induced Whole-Body Vibration and Prevention by Human Apolipoprotein A-I Molecule Mimetic (4F) Peptide (an Apo A-I Mimetic).

BACKGROUND: Insidious cumulative brain injury from motor vehicle-induced whole-body vibration (MV-WBV) has not yet been studied. The objective of the present study is to validate whether whole-body vibration for long periods causes cumulative brain injury and impairment of the cerebral function. We also explored a preventive method for MV-WBV injury. METHODS: A study simulating whole-body vibration was conducted in 72 male Sprague-Dawley rats divided into 9 groups (N = 8): (1) 2-week normal control; (2) 2-week sham control (in the tube without vibration); (3) 2-week vibration (exposed to whole-body vibration at 30 Hz and .5 G acceleration for 4 hours/day, 5 days/week for 2 weeks; vibration parameters in the present study are similar to the most common driving conditions); (4) 4-week sham control; (5) 4-week vibration; (6) 4-week vibration with human apolipoprotein A-I molecule mimetic (4F)-preconditioning; (7) 8-week sham control; (8) 8-week vibration; and (9) 8-week 4F-preconditioning group. All the rats were evaluated by behavioral, physiological, and histological studies of the brain. RESULTS: Brain injury from vibration is a cumulative process starting with cerebral vasoconstriction, squeezing of the endothelial cells, increased free radicals, decreased nitric oxide, insufficient blood supply to the brain, and repeated reperfusion injury to brain neurons. In the 8-week vibration group, which indicated chronic brain edema, shrunken neuron numbers increased and whole neurons atrophied, which strongly correlated with neural functional impairment. There was no prominent brain neuronal injury in the 4F groups. CONCLUSIONS: The present study demonstrated cumulative brain injury from MV-WBV and validated the preventive effects of 4F preconditioning.

Neural systemic impairment from whole-body vibration.

Insidious brain microinjury from motor vehicle-induced whole-body vibration (WBV) has not yet been investigated. For a long time we have believed that WBV would cause cumulative brain microinjury and impair cerebral function, which suggests an important risk factor for motor vehicle accidents and secondary cerebral vascular diseases. Fifty-six Sprague-Dawley rats were divided into seven groups (n = 8): 1) 2-week normal control group, 2) 2-week sham control group (restrained in the tube without vibration), 3) 2-week vibration group (exposed to whole-body vibration at 30 Hz and 0.5g acceleration for 4 hr/day, 5 days/week, for 2 weeks), 4) 4-week sham control group, 5) 4-week vibration group, 6) 8-week sham control group, and 7) 8-week vibration group. At the end point, all rats were evaluated in behavior, physiological, and brain histopathological studies. The cerebral injury from WBV is a cumulative process starting with vasospasm squeezing of the endothelial cells, followed by constriction of the cerebral arteries. After the 4-week vibration, brain neuron apoptosis started. After the 8-week vibration, vacuoles increased further in the brain arteries. Brain capillary walls thickened, mean neuron size was obviously reduced, neuron necrosis became prominent, and wide-ranging chronic cerebral edema was seen. These pathological findings are strongly correlated with neural functional impairments.

Spindle Cell Lipoma of the Neck: Review of the Literature and Case Report.

Spindle cell lipomas (SCL) are benign, slow growing tumors arising most frequently in the subcutaneous tissue of the upper back, posterior neck, and shoulders in males aged 40-70 years. Local excision is generally curative. Classification of lipomatous tumors has progressed recently, and tumors of similar morphology and unusual presentation are increasingly reported, thereby making correct diagnosis even more vital. SCL require pathologic differentiation from liposarcoma, other spindle cell neoplasms, and myxoid lesions for treatment purposes. Cytology, histology, and cytogenetics, in conjunction with clinical presentation, are paramount in arriving at the correct diagnosis of spindle cell lipoma. We present a case report with characteristics typical of an SCL along with a literature review to further elucidate the diagnosis and surgical treatment of this soft tissue tumor.

Calcitonin pump improves nerve regeneration after transection injury and repair.

INTRODUCTION: After nerve injury, excessive calcium impedes nerve regeneration. We previously showed that calcitonin improved nerve regeneration in crush injury. We aimed to validate the direct effect of calcitonin on transected and repaired nerve. METHODS: Two rat groups (n = 8) underwent sciatic nerve transection followed by direct repair. In the calcitonin group, a calcitonin-filled mini-osmotic pump was implanted subcutaneously, with a catheter parallel to the repaired nerve. The control group underwent repair only, without a pump. Evaluation and comparison between the groups included: (1) compound muscle action potential recording of the extensor digitorum longus (EDL) muscle; (2) tetanic muscle force test of EDL; (3) nerve calcium concentration; and (4) nerve fiber count and calcified spot count. RESULTS: The calcitonin pump group showed superior recovery. CONCLUSIONS: Calcitonin affects injured and repaired peripheral nerve directly. The calcitonin-filled mini-osmotic pump improved nerve functional recovery by accelerating calcium absorption from the repaired nerve. This finding has potential clinical applications.

Detergent-free Decellularized Nerve Grafts for Long-gap Peripheral Nerve Reconstruction.

BACKGROUND: Long-gap peripheral nerve defects arising from tumor, trauma, or birth-related injuries requiring nerve reconstruction are currently treated using nerve autografts and nerve allografts. Autografts are associated with limited supply and donor-site morbidity. Allografts require administration of transient immunosuppressants, which has substantial associated risks. To overcome these limitations, we investigated the use of detergent-free decellularized nerve grafts to reconstruct long-gap nerve defects in a rodent model and compared it with existing detergent processing techniques. METHODS: Nerve grafts were harvested from the sciatic nerves of 9 donor rats. Twenty-four recipient rats were divided into 4 groups (6 animals per group): (1) nerve grafts (NG, positive control), (2) detergent-free decellularized (DFD) grafts, (3) detergent decellularized grafts, and (4) silicone tube conduits (negative control). Each recipient rat had a 3.5-cm graft or conduit sutured across a sciatic nerve transection injury. All animals were harvested at 12 weeks postimplantation for functional muscle analysis and nerve histomorphometry. RESULTS: Histomorphometry results indicated maximum growth in NG when compared with other groups. DFD and detergent decellularized groups showed comparable regeneration at 12 weeks. Silicone tube group showed no regeneration as expected. Muscle force data indicated functional recovery in NG and DFD groups only. CONCLUSIONS: This study describes a detergent-free nerve decellularization technique for reconstruction of long-gap nerve injuries. We compared DFD grafts with an established detergent processing technique and found that DFD nerve grafts are successful in promoting regeneration across long-gap peripheral nerve defects as an alternative to existing strategies.