Histologic and Functional Outcomes of Conduit Wrapping for Peripheral Nerve Repair: Early Results in a Rat Model.

BACKGROUND: The concept of utilizing a nerve conduit for augmentation of a primary nerve repair has been advocated as a method to prevent neural scarring and decrease adhesions. Despite clinical use, little is known about the effects of a nerve conduit wrapped around a primary repair. To better understand this, we investigated the histologic and functional effects of use of a nerve conduit wrapped around a rat sciatic nerve repair without tension. METHODS: Twenty Lewis' rats were divided into two groups of 10 rats each. In each group, unilateral sciatic nerve transection and repair were performed, with the opposite limb utilized as a matched control. In the first group, direct repair alone was performed; in the second group, this repair was augmented with a porcine submucosa conduit wrapped around the repair site. Sciatic functional index (SFI) was measured at 6 weeks with walking track analysis in both groups. Nonsurvival surgeries were then performed in all animals to harvest both the experimental and control nerves to measure histomorphometric parameters of recovery. Histomorphometric parameters assessed included total number of neurons, nerve fiber density, nerve fiber width, G-ratio, and percentage of debris. Unpaired t-test was used to compare outcomes between the two groups. RESULTS: All nerves healed uneventfully but compared with direct repair; conduit usage was associated with greater histologic debris, decreased axonal density, worse G-ratio, and worse SFI. No significant differences were found in total axon count or gastrocnemius weight. CONCLUSION: In the absence of segmental defects, conduit wrapping primary nerve repairs seem to be associated with worse functional and mixed histologic outcomes at 6 weeks, possibly due to debris from conduit resorption. While clinical implications are unclear, more basic science and clinical studies should be performed prior to widespread adoption of this practice.

Odontogenic Cysts and Tumors.

Odontogenic cysts and tumors are mandibular and maxillary lesions that occur across all patient demographics across age, sex, race, and social economic status, as altered remnants of dental development. They may be incidental findings from routine imaging in any office or found through workup for craniofacial surgery or injury. Many of these patients present with asymptomatic lesions, whereas others may be symptomatic. In this article, we review the literature on the most common odontogenic tumors and cysts and discuss their presentation, their defining traits, and how to approach diagnosis and definitive management.

Snapping Triceps Syndrome.

Snapping triceps syndrome is a rarely diagnosed condition that can present with symptoms of ulnar neuritis or as an isolated problem itself. First described in 1970, this syndrome is minimally present in the literature with a few mechanistic studies, anatomical studies, radiological reports, and occasional case reports or series. In this article, we briefly review the literature, discuss potential causes and typical presentations of snapping triceps syndrome, and describe our operative technique. We also provide a representative case with intraoperative videos that illustrate the pathology and surgical treatment.

The Effect of 3rd Carpometacarpal Arthrodesis in the Outcomes of Total Wrist Fusion Using Modern Plate Technology.

Background The inclusion of the third carpometacarpal (CMC) joint in the fusion mass in total wrist fusion (TWF) remains controversial. Our goal was to evaluate the clinical outcomes and effects of third CMC joint arthrodesis compared with bridging the CMC joint during TWF. A retrospective chart review was performed. Outcomes assessed included hardware loosening, hardware failure, symptomatic hardware necessitating removal, and need for revision arthrodesis. Case Description/Literature Review We found that concomitant third CMC joint arthrodesis was associated with a significantly reduced rate of radiocarpal and midcarpal joint nonunion, hardware loosening, and symptomatic hardware removal when compared to bridging of the CMC joint. There was no significant difference in hardware failure rates or the need for revision arthrodesis. Clinical Relevance When using a contoured dorsal spanning plate, concomitant CMC joint arthrodesis should be considered during TWF to mitigate against hardware loosening and symptomatic hardware. Level of Evidence Level IV.

A New Source of Mutilating Hand Injuries: The Side-by-Side Utility Terrain Vehicle.

BACKGROUND: Rates of mutilating hand injuries are increasing from accidents caused by all-terrain vehicles (ATVs) and the recently popularized side-by-side utility terrain vehicles (UTVs). Increasing surgeon familiarity with upper extremity (UE) injury patterns, severity, and outcomes following ATV and UTV accidents may improve patient care and advocacy. METHODS: Retrospective comparisons of UE injury patterns, severity, hospital and intensive care unit (ICU) admission lengths, and number of operations were made between ATVs and UTVs. Findings were analyzed with Fisher exact tests, multivariate analysis of variance, analyses of variance with post hoc analyses, and multiple linear regressions. RESULTS: A total of 154 cases were identified for inclusion (ATV, n = 87; UTV, n = 67). Patient ages ranged from 4 to 89 years. The UTV group contained significantly more hand and finger injuries, and more of the fractures were open ( P = 0.005, P < 0.001, and P < 0.001, respectively). Riders of UTVs had nearly three times as many mutilating hand injuries and a nearly ninefold increase in amputations compared with ATV riders ( P < 0.001 and P < 0.001, respectively). On average, the UTV group spent 2.5 additional days in the hospital, 0.91 additional days in an ICU, and had 1.3 additional operations ( P = 0.001, P = 0.007, and P < 0.001, respectively). Vehicle type was the only variable significantly correlated with days in the hospital, ICU, and number of UE operations ( P = 0.002, P = 0.008, and P < 0.001, respectively). CONCLUSIONS: Hand surgeons are in a unique position to serve as forerunners for increasing public awareness of off-road vehicle risks and promoting rider safety. Collaborating with manufacturers and emergency care providers and directing teaching initiatives may improve patient outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

Influences of Repair Site Tension and Conduit Splinting on Peripheral Nerve Reconstruction.

BACKGROUND: We investigated the use of a conduit splinting technique to mitigate tension at the coaptation site of a rodent nerve defect model to determine the optimal reconstruction method for segmental nerve defects. METHODS: A rat sciatic nerve segmental defect model was created by excising 5mm of the sciatic nerve unilaterally. Four groups of 10 rats were each reconstructed using 1 of 4 techniques: primary repair, repair with conduit splinting, reverse isograft with conduit splinting, and reverse isograft without splinting. Functional outcomes were assessed at 6 weeks by measurement of Sciatic Functional Index (SFI), and sciatic nerves were harvested at the nonsurvival surgery. Histomorphologic measurements were reported as a value normalized to the average measurements of the control side. The primary outcomes were assessment of nerve continuity and the proportion of nerve fibers in the regenerating nerve compared with the uninjured side. RESULTS: The number of repair site rupture rates was lower when a conduit splint was used-less than half of the primary repairs under tension remained intact at 6 weeks. No difference was seen in axon number, size, and density between primary repairs and those augmented by conduit splints, but worse functional outcomes and more debris were present compared with the intact primary repairs. CONCLUSIONS: Nerve conduit splinting reduced rupture rates, particularly for nerve repairs associated with a segmental defect. No significant difference was seen in the number of axons among techniques. Primary nerve repair under tension that did not rupture demonstrated superior SFI.

Does Proximal Row Carpectomy Improve Union in Wrist Arthrodesis? A Retrospective Cohort Study.

Background Some surgeons advocate for concomitant proximal row carpectomy (PRC) with total wrist arthrodesis (TWA), though there are limited data to support or oppose this view. Questions/Purposes Does concomitant PRC improve rates of union, revision, hardware loosening, hardware failure, and hardware removal in TWA? Patients and Methods A retrospective cohort study of patients who underwent TWA with and without concomitant PRC between January 2008 and December 2018 was undertaken. Patients were included if they underwent TWA using a dorsal spanning plate. Patients were excluded if they underwent partial wrist arthrodesis, revision TWA, or TWA with nondorsal spanning plate fixation. Results A total of 183 wrists in 180 patients were included in the study, 96 (52.5%) in the TWA only and 87 (47.5%) in the TWA + PRC groups. Median clinical and radiographic follow-up was 18.0 months (3.0-133.0 months) in the TWA + PRC group and 18.5 months (2.0-126.0 months) in the TWA only group ( p = 0.907). No difference in nonunion (TWA + PRC: 13/87 [14.9%], TWA only: 18/96 [18.8%], odds ratio: 0.76, p = 0.494), revision (TWA + PRC: 5/87 [5.75%], TWA only: 8/96 [8.33%], hazard ratio [HR]: 0.73, p = 0.586), loosening (TWA + PRC: 4/87 [4.60%], TWA only: 6/96 [6.25%], HR: 0.74, p = 0.646), failure (TWA + PRC: 5/87 [5.75%], TWA only: 4/96 [4.17%], HR: 1.55, p = 0.530), and removal (TWA + PRC: 12/87 [13.8%], TWA only: 16/96 [16.7%], HR: 0.84, p = 0.634) were identified. Conclusion Concomitant PRC might not improve rates of union or diminish complications in patient undergoing TWA. The role of PRC and the rationale for its use in TWA need to be individualized and discussed with patients prior to surgery. Level of Evidence This is a Level IV, therapeutic study.

Extensor pollicis longus tendon rupture from Dorsal Nail Plate distal radius fixation with concomitant myostatic atrophy.

Distal radius fractures are one of the most common upper extremity injuries seen by hand surgeons each year. Many of these fractures require reduction and surgical fixation because of displacement, comminution or inherent fracture instability. New hardware is designed and introduced each year to help surgeons manage these injuries. We report a case of a major complication from the use of the Dorsal Nail Plate hardware. The patient presented to our clinic with an extensor pollicis longus attrition rupture, which required tendon transfer for treatment. Intraoperatively, we also found ongoing extensor digitorum communis tendon attrition, myostatic atrophy of the extensor pollicus longus and ultimately a large bony defect following complex hardware removal. This case serves as a reminder to consider the potential complication profile of any hardware or technique you are considering using in your patients and to evaluate donor muscles and tendons when performing grafting or transfers.

Osteonecrosis of the Lunate: Kienböck Disease.

Kienböck disease, osteonecrosis of the lunate, is a well-known but poorly understood complication seen by hand surgeons. This review presents the background and important patient-specific parameters of the disease and reviews the numerous treatment options that exist for the disease.

Knotless single-row rotator cuff repair: a comparative biomechanical study of 2 knotless suture anchors.

The purpose of this study was to compare the gap formation during cyclic loading, maximum repair strength, and failure mode of single-row full-thickness supraspinatus repairs performed using 2 knotless suture anchors with differing internal suture-retention mechanisms in a human cadaver model. Nine matched pairs of cadaver shoulders were used. Full-thickness tears were induced by detaching the supraspinatus tendon from the greater tuberosity. Single-row repairs were performed with either type I (Opus Magnum PI; ArthroCare, Austin, Texas) or type II (ReelX STT; Stryker, Mahwah, New Jersey) knotless suture anchors. The repaired tendon was cycled from 10 to 90 N for 500 cycles, followed by load to failure. Gap formation was measured at 5, 100, 200, 300, 400, and 500 cycles with a video digitizing system. Anchor type or location (anterior or posterior) had no effect on gap formation during cyclic loading regardless of position (anterior, P=.385; posterior, P=.389). Maximum load to failure was significantly greater (P=.018) for repairs performed with type II anchors (288±62 N) compared with type I anchors (179±39 N). Primary failure modes were anchor pullout and tendon tearing for type II anchors and suture slippage through the anchor for type I anchors. The internal ratcheting suture-retention mechanism of type II anchors may have helped this anchor outperform the suture-cinching mechanism of type I anchors by supporting significantly higher loads before failure and minimizing suture slippage, potentially leading to stronger repairs clinically.