Gregory A. Merrell

Comparison of nerve transfers and nerve grafting for traumatic upper plexus palsy: a systematic review and analysis.

BACKGROUND In treating patients with brachial plexus injury, there are no comparative data on the outcomes of nerve grafts or nerve transfers for isolated upper trunk or C5-C6-C7 root injuries. The purpose of our study was to compare, with systematic review, the outcomes for modern intraplexal nerve transfers for shoulder and elbow function with autogenous nerve grafting for upper brachial plexus traumatic injuries. METHODS PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for studies in which patients had surgery for traumatic upper brachial plexus palsy within one year of injury and with a minimum follow-up of twelve months. Strength and shoulder and elbow motion were assessed as outcome measures. The Fisher exact test and Mann-Whitney U test were used to compare outcomes, with an alpha level of 0.05. RESULTS Thirty-one studies met the inclusion criteria. Two hundred and forty-seven (83%) and 286 (96%) of 299 patients with nerve transfers achieved elbow flexion strength of grade M4 or greater and M3 or greater, respectively, compared with thirty-two (56%) and forty-seven (82%) of fifty-seven patients with nerve grafts (p < 0.05). Forty (74%) of fifty-four patients with dual nerve transfers for shoulder function had shoulder abduction strength of grade M4 or greater compared with twenty (35%) of fifty-seven patients with nerve transfer to a single nerve and thirteen (46%) of twenty-eight patients with nerve grafts (p < 0.05). The average shoulder abduction and external rotation was 122° (range, 45° to 170°) and 108° (range, 60° to 140°) after dual nerve transfers and 50° (range, 0° to 100°) and 45° (range, 0° to 140°) in patients with nerve transfers to a single nerve. CONCLUSIONS In patients with demonstrated complete traumatic upper brachial plexus injuries of C5-C6, the pooled international data strongly favors dual nerve transfer over traditional nerve grafting for restoration of improved shoulder and elbow function. These data may be helpful to surgeons considering intraoperative options, particularly in cases in which the native nerve root or trunk may appear less than optimal, or when long nerve grafts are contemplated.

Flexor tendon repair with a knotless barbed suture: a comparative biomechanical study.

PURPOSE To test the hypothesis that a flexor tendon repair with only a knotless barbed suture technique provides a repair with a greater maximal load to failure and 2-mm gapping resistance than a traditional technique using a 4-strand core plus a running-locking epitendinous suture. METHODS We assigned 41 fresh-frozen cadaveric flexor digitorum profundus tendons for repair by either a traditional technique using a 4-strand core (Tajima and horizontal mattress) plus a running-locking epitendinous suture (n = 20) or a bidirectional barbed suture technique using a knotless, 4-strand core secured with 3 transverse passes (n = 21). A biomechanical study was performed on each tendon-suture construct and the tendons were linearly distracted to failure at 100 mm/min. The maximal tensile load to failure, 2-mm gapping tensile load, and mode of failure were determined and statistically compared. RESULTS The average maximal load to failure was not significantly different between the traditional repair (48 ± 12 N) and the barbed suture repair (50 ± 14 N). The average 2-mm gapping load was also insignificantly different between the traditional repair (42 ± 12 N) and the barbed suture repair (32 ± 9 N). The traditional repair failed by knot unraveling and suture rupture 35% and 65% of the time, respectively. The barbed suture repair failed by suture pull-out and rupture 67% and 33% of the time, respectively. The average load to failure by suture rupture was insignificantly different between the traditional repair (51 ± 13 N) and the barbed suture repair (63 ± 16 N). The average load to failure by knot unraveling using the traditional repair was 43 ± 11 N, whereas the average load to failure by suture pull-out using the barbed suture repair was 43 ± 8 N. CONCLUSIONS The barbed suture repair did not demonstrate a significant difference in maximal load to failure and 2-mm gapping resistance compared with the traditional method of repair. CLINICAL RELEVANCE This study examines the biomechanical differences between 2 types of flexor-tendon repair, which can help guide the surgical management for these injuries.

Arthroscopic technique for medial epicondylitis: technique and safety analysis.

PURPOSE The goals of this study are to report on a novel arthroscopic technique for the treatment of medial epicondylitis and to further describe the anatomic relations between the site of arthroscopic debridement and both the ulnar nerve and medial collateral ligament (MCL) complex. METHODS Arthroscopic debridement of the medial epicondyle was performed on 8 fresh-frozen cadaveric specimens. Each specimen was dissected, and the shortest distance from the debridement site to both the ulnar nerve and MCL complex was measured with a 3-dimensional motion-tracking system. RESULTS The mean distance between the debridement site and the ulnar nerve was 20.8 mm (range, 14.4 to 25.1 mm), and the mean distance between the medial debridement site and the origin of the anterior bundle of the MCL was 8.3 mm (range, 5.9 to 10.4 mm). CONCLUSIONS Our results suggest that arthroscopic debridement of the medial epicondyle can be performed with low risk of injury to the ulnar nerve or MCL complex. CLINICAL RELEVANCE This cadaveric study indicates a potential role for elbow arthroscopy in the surgical management of refractory medial epicondylitis.

Prevention of childhood pedestrian trauma: A study of interventions over six years

Pedestrian injury is second only to cancer as the leading cause of death of children between the ages of five and nine years1,2. Furthermore, pedestrian injury accounts for 31% to 61% of all admissions of children to the hospital for treatment of injuries3-5. In the United States, rates of pedestrian injuries among children are estimated to be 111 per 100,000 and account for approximately 18,000 hospital admissions each year6-8. In 1996, 1191 children under the age of sixteen were killed in pedestrian-motor vehicle collisions9. Operative intervention is required after approximately 11% of pedestrian injuries, and hospital admission is required after 36%10,11. Pedestrian injuries are more likely to be severe than are injuries sustained by motor-vehicle occupants, and they are associated with a higher rate of mortality (4% compared with 0.5%)12. Mortality is caused by multisystem trauma (80%) or isolated head injury (20%)13. There are three phases of injury in a pedestrian-motor vehicle collision14. The initial impact from the bumper often results in lower-extremity injuries. Next, head and torso injuries are sustained as the victim strikes the hood or windshield. Finally, additional head, torso, and upper-extremity injuries occur as the child falls to the ground. There is a high incidence of head injury with attendant increases in morbidity and mortality15,16. In one series of more than 1900 children who had been struck by a motor vehicle, 31% had intracranial injuries, 14% had lower-extremity fractures, and 2% had pelvic fractures10. Given the height of a bumper strike, children under three years of age sustain femoral fractures twice as often as they sustain tibial or fibular fractures, whereas lower-extremity injuries in older patients …

Effects of long-term fixation on histological quality of undecalcified murine bones embedded in methylmethacrylate

While long-term fixation and storage of specimens is common and useful for many research projects, it is particularly important for space flight investigations where samples may not be returned to Earth for several months (International Space Station) or years (manned mission to Mars). We examined two critical challenges of space flight experimentation: the effect of long-term fixation on the quality of mouse bone preservation and the preservation of antigens and enzymes for both histochemical and immunohistochemical analyses, and how the animal/sample processing affects the preservation. We show that long-term fixation minimally affects standard histological staining, but that enzyme histochemistry and immunolabeling are greatly compromised. Further, we demonstrate that whole animal preservation is not as suitable as whole leg or stripped leg preservation for long-term fixation and all histological analyses. Overall, we recommend whole leg processing for long-term storage of bone specimens in fixative prior to embedding in plastic for histological examination.

A Multicenter, Prospective, Randomized, Pilot Study of Outcomes for Digital Nerve Repair in the Hand Using Hollow Conduit Compared With Processed Allograft Nerve

Background: Current repair options for peripheral nerve injuries where tension-free gap closure is not possible include allograft, processed nerve allograft, and hollow tube conduit. Here we report on the outcomes from a multicenter prospective, randomized, patient- and evaluator-blinded, pilot study comparing processed nerve allograft and hollow conduit for digital nerve reconstructions in the hand. Methods: Across 4 centers, consented participants meeting inclusion criteria while not meeting exclusion criteria were randomized intraoperatively to either processed nerve allograft or hollow conduit. Standard sensory and safety assessments were conducted at baseline, 1, 3, 6, 9, and 12 months after reconstruction. The primary outcome was static 2-point discrimination (s2PD) testing. Participants and assessors were blinded to treatment. The contralateral digit served as the control. Results: We randomized 23 participants with 31 digital nerve injuries. Sixteen participants with 20 repairs had at least 6 months of follow-up while 12-month follow-up was available for 15 repairs. There were no significant differences in participant and baseline characteristics between treatment groups. The predominant nerve injury was laceration/sharp transection. The mean ± SD length of the nerve gap prior to repair was 12 ± 4 mm (5-20 mm) for both groups. The average s2PD for processed allograft was 5 ± 1 mm (n = 6) compared with 8 ± 5 mm (n = 9) for hollow conduits. The average moving 2PD for processed allograft was 5 ± 1 mm compared with 7 ± 5 mm for hollow conduits. All injuries randomized to processed nerve allograft returned some degree of s2PD as compared with 75% of the repairs in the conduit group. Two hollow conduits and one allograft were lost due to infection during the study. Conclusions: In this pilot study, patients whose digital nerve reconstructions were performed with processed nerve allografts had significantly improved and more consistent functional sensory outcomes compared with hollow conduits.

Paraumbilical Perforator Flap for Soft Tissue Reconstruction of the Forearm

Numerous flaps exist for coverage of injuries to the upper extremity, ranging from local, to regional, to free tissue transfer. The choice of flap is dependent on a variety of factors, including patient, functional needs, and depth of injury. The paraumbilical perforator (PUP) flap for upper extremity coverage can offer the benefits and versatility of pedicled and free flaps while avoiding some of the donor-site morbidity and risks of free tissue transfer. We report the indications and management of two clinical cases that exemplify PUP flap application. Technical points of flap harvest, inset, timing of pedicle division, and pertinent anatomy are discussed.

Adult Brachial Plexus and Thoracic Outlet Surgery

Brachial plexus surgical treatment, though complex, has evolved substantially over the past 40 years as technology and microsurgical techniques have continued to improve. Options for repair, depending on the type and level of injury, include neurolysis, direct repair, nerve grafting, nerve transfer, arthrodesis, and muscle and tendon transfer. A comprehensive review of the indications, preoperative work-up, and surgical approach is presented, along with outcomes, complications, and postoperative management. We conclude with a discussion of the evaluation and management of patients with thoracic outlet syndrome.

Comparing Biomechanical Properties, Repair Times, and Value of Common Core Flexor Tendon Repairs

Background: The aim of the study was to compare biomechanical strength, repair times, and repair values for zone II core flexor tendon repairs. Methods: A total of 75 fresh-frozen human cadaveric flexor tendons were harvested from the index through small finger and randomized into one of 5 repair groups: 4-stranded cross-stitch cruciate (4-0 polyester and 4-0 braided suture), 4-stranded double Pennington (2-0 knotless barbed suture), 4-stranded Pennington (4-0 double-stranded braided suture), and 6-stranded modified Lim-Tsai (4-0 looped braided suture). Repairs were measured in situ and their repair times were measured. Tendons were linearly loaded to failure and multiple biomechanical values were measured. The repair value was calculated based on operating room costs, repair times, and suture costs. Analysis of variance (ANOVA) and Tukey post hoc statistical analysis were used to compare repair data. Results: The braided cruciate was the strongest repair (P > .05) but the slowest (P > .05), and the 4-stranded Pennington using double-stranded suture was the fastest (P > .05) to perform. The total repair value was the highest for braided cruciate (P > .05) compared with all other repairs. Barbed suture did not outperform any repairs in any categories. Conclusions: The braided cruciate was the strongest of the tested flexor tendon repairs. The 2-mm gapping and maximum load to failure for this repair approached similar historical strength of other 6- and 8-stranded repairs. In this study, suture cost was negligible in the overall repair cost and should be not a determining factor in choosing a repair.

Distal Biceps Brachii Tendon Transfer for Re-establishing Extrinsic Finger Function: Feasibility Study in Cadavers

PURPOSE To determine the anatomic feasibility of transferring the biceps brachii tendon into either the extensor digitorum communis (EDC) or flexor digitorum profundus (FDP), determine the excursion imparted to EDC and FDP tendons after transfer, and compare the work capacity of the cadaver biceps to previously published data on the biceps as well as the recipient muscles by calculating the physiologic cross-sectional area (PCSA). METHODS Four fresh-frozen cadaver shoulder-elbow-wrist specimens were used to measure tendon excursion that can be obtained with transfer of the distal biceps tendon into either the EDC or FDP. Two cadavers had distal biceps-to-EDC transfer performed, and the other 2 had distal biceps-to-FDP performed. Passive ranging of each elbow from flexion to extension and active loading at 90° of elbow flexion were then performed on each specimen to determine tendon excursion. An analysis of the PCSA of the biceps muscle was performed on each specimen. RESULTS Distal biceps-to-EDC transfer resulted in an average of 24 mm of tendon excursion with passive loading, and 24 mm of tendon excursion with active loading. Distal biceps-to-FDP transfer resulted in an average of 24 mm of tendon excursion with passive loading, and 24 mm of tendon excursion with active loading. The average PCSA was 3.6 cm2. CONCLUSIONS Transfer of the distal biceps tendon into the EDC or FDP is anatomically feasible and provides roughly 24 mm of tendon excursion to the tendon units. The PCSA in the specimens used is slightly lower than other published data; it closely approximates the PCSA of the EDC, but is only half of the PCSA of the FDP in previously published data. CLINICAL RELEVANCE The findings suggest potentially novel transfer options for restoring finger flexion and extension in patients lacking FDP or EDC function.