Injury and Biological Factors Impact Shoulder Function following Autogenous Grafting of Spinal Nerves for Pan-Brachial Plexus Reconstruction.

BACKGROUND: Shoulder function following spinal nerve grafting in pan-brachial plexus injuries(Pan-BPI) is not well described. The purpose of this study was twofold: 1)to evaluate shoulder abduction(ABD) and external rotation(ER) after grafting of viable spinal nerves to the suprascapular nerve(SSN), axillary nerve(AxN), or posterior division of the upper trunk(PDUT); and 2)to determine patient characteristics, injury severity/characteristics, and nerve graft factors that influenced outcomes. METHODS: 362 Pan-BPI reconstruction patients from a single institution were reviewed for those who underwent spinal nerve grafting for shoulder reanimation between 2001 and 2018. Patient demographics, injury severity scores(ISS), graft characteristics, strength, range of motion for shoulder ABD and ER, and patient-reported outcomes were recorded. Patients were divided into three groups based on the recovery of shoulder function: no return, ABD only, and ABD and ER. RESULTS: 110 patients underwent spinal nerve grafting, with 41 meeting inclusion criteria. 17(41.5%) had no return of shoulder function, 14(34.1%) had ABD alone, and 10(24.4%) had ABD and ER. Patients with recovery of both ABD and ER were significantly younger(18.6±5.56), had lower BMI(22.4±4.0), and lower ISS(10.5±6.24, p=0.003). Multivariable analysis found that with increasing age(OR:0.786, 95%CI:0.576,0.941) and ISS(OR:0.820, 95%CI:0.606-0.979), odds for return of ABD and ER significantly decreased. CONCLUSIONS: In Pan-BPI, 24.4% of patients demonstrated return of both ABD and ER following spinal nerve grafting to SSN and either AxN or PDUT. Age, BMI, and ISS were associated with poorer recovery of shoulder function. Careful patient selection and consideration of age, BMI, and ISS may improve outcomes of spinal nerve grafting for shoulder reanimation. LEVEL OF EVIDENCE: III.

Combined Wrist Extensor Tenodesis and Tendon Transfers for Severe Spastic Flexed Wrist Deformity: Surgical Technique and Case Series.

Spastic wrist flexion deformities both limit the functional use of the hand for grasp and pinch producing a stigmatizing appearance. Tendon transfers and total wrist arthrodesis are treatment options for this condition depending on the patient's characteristics, the latter the most commonly used in patients with severe wrist flexion deformities. Tendon transfers alone in this scenario have the tendency for recurrent deformity due to tenorrhaphy failure or soft tissue creep and resultant loss of tension. Total wrist arthrodesis is a more invasive procedure, which can have hardware or fusion problems and that is irreversible. We propose a novel technique that incorporates a distally based wrist extensor tendon slip and suture tape tenodesis to the distal radius. The rationale of this technique is to act as a protective, internal splint to prevent recurrent deformity after primary or revision tendon transfer for moderate to severe spastic flexed wrist deformities, avoiding the need to perform a total wrist arthrodesis.

Validation of the Root Analysis Score for C5 Viability in Patients With Pan-Brachial Plexus Injury.

PURPOSE: Pan-brachial plexus injury patients present a reconstructive challenge. The root analysis score, developed from parsimonious multivariable modeling of 311 pan-brachial plexus injury patients, determines the probability of having a viable C5 nerve based on four categories: positive C5 Tinel test, intact C5 nerve on computed tomography myelogram, lack of hemidiaphragmatic elevation, and absence of midcervical paraspinal fibrillations. METHODS: Root analysis scores were calculated for a separate cohort of patients with pan-brachial plexus injuries. Scores were validated by the presence or absence of a graftable C5 root, based on supraclavicular exploration and intraoperative electrophysiologic testing. Receiver operating characteristic curve, accuracy, and concordance statistic of the scores were calculated. Patients were divided into three root analysis score cohorts: less than 50 (low), 50-75 (average), and 75-100 points (high) based on dividing the score into quartiles and combining the lowest two. The probability, sensitivity, and specificity of each cohort having an available C5 nerve were based on the intraoperative assessment. RESULTS: Eighty patients (mean age, 33.1 years; 15 women and 65 men) were included. Thirty-one patients (39%) had a viable C5 nerve. The root analysis calculator had an overall accuracy of 82.5%, a receiver operating characteristic of 0.87, and a concordance statistic of 0.87, demonstrating high overall predictive value; 6.5% of patients with a score of less than 50 (94% sensitivity and 43% specificity), 16.1% of patients with a score of 50-75 (94% sensitivity and 67% specificity), and 77.4% of patients with a score of 75-100 (77% sensitivity and 90% specificity) had a graftable C5 nerve. CONCLUSIONS: The root analysis score demonstrated high accuracy and predictive power for a viable C5 nerve. In patients with a score of less than 50, the necessity of supraclavicular root exploration should balance patient factors, presentation timing, and concomitant injuries. TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnosis II.

In search of zebras: Critical analysis of the rarity of perineural breast cancer spread to the brachial plexus in men.

BACKGROUND: Perineural spread (PNS) of breast cancer to the brachial plexus is rare, with reports limited to cases only in female patients. This study aimed to determine the incidence of PNS in male compared with female patients. METHODS: Adult breast cancer patients referred to a single institution between 1994 and 2022 were retrospectively reviewed for imaging or biopsy-confirmed cases of PNS to the brachial plexus. Two independent reviewers of articles published in any language between 1990 and 2022 in PubMed, Scopus, Embase, and Google Scholar performed a systematic literature review. RESULTS: Of the 10,466 patients with breast cancer (10,355 female, 111 male) referred to a single institution, there were 42 female patients with PNS to the brachial plexus for an estimated incidence of 0.4%. In the same time period, there were 111 male patients treated for breast cancer, including 88 patients with Klinefelter's syndrome (KS); however, there were no cases of male patients with PNS. A systematic review of the world's literature did not identify male patients with PNS to the brachial plexus. CONCLUSIONS: There is a lack of any reported cases of PNS of breast cancer to the brachial plexus in men or patients with KS, who have a much higher incidence of breast cancer. This may reflect either the compounding rarity of these two events or point toward a distinct hormonally-driven link between breast cancer and PNS, highlighted by the disparity in PNS incidence in men and women.

Combined Hyperselective Neurectomy and Fractional Lengthening Technique for Triceps Spasticity.

Triceps spasticity can occur in patients with upper motor neuron syndrome. It is often undetected when there is predominant elbow flexion spasticity and/or contracture. This condition can become apparent after surgery for elbow flexor spasticity, leading to impaired active elbow. Although triceps muscle-tendon lengthening procedures can be performed, these techniques do not directly address the issue of spasticity which is neurally mediated. This article presents a surgical technique for addressing triceps spasticity with a combined approach of hyperselective neurectomy of the medial head of the triceps and muscle-tendon lengthening of the long and lateral heads.

Segmental extraneural lipomatosis of the superficial peroneal nerve: illustrative case.

BACKGROUND: Adipose lesions of nerve are rare tumors that can cause nerve symptoms from either intrinsic or extrinsic compression. OBSERVATIONS: The authors present a case of a patient with a 10-year history of progressive, persistent leg pain and dorsal foot paresthesias/dysesthesias. Imaging revealed several nondistinct nodules of indeterminate significance along the course of the superficial peroneal nerve (SPN). Surgery demonstrated six distinct extraneural lipomas studded on a 10-cm segment of the main SPN and one of its muscular branches in the midleg. The lesions were adherent to the SPN, without an easy dissection plane; therefore, a neurectomy was performed. Histology revealed the nerve was associated with multiple extraneural lipomas with focal evidence of prior trauma. At 4 months postoperatively, the patient's pain had resolved completely, and she was able to resume normal physical activities. LESSONS: The current classification of adipose lesions of nerve includes intraneural and extraneural lipomas and lipomatosis of nerve (fibrolipomatous hamartoma). The unique features of the present case include the discrete and segmental nature of the extraneural lipomas adherent to the nerve. Its etiology is unknown, and the histology would be suggestive of either a traumatic or a degenerative process.

"Winged" Eagle's syndrome: neurophysiological findings in a rare cause of spinal accessory nerve palsy. Illustrative cases.

BACKGROUND: Eagle's syndrome (ES) classically describes dysphagia, globus sensation, and otalgia from an elongated and calcified styloid process or stylohyoid ligament. Compression of the spinal accessory nerve (SAN) has not been reported as an associated feature of ES or related variants. OBSERVATIONS: The authors describe two cases of an atypical "winged" variant with SAN palsy resulting from compression by a posteriorly angulated or calcified styloid process. Both patients exhibited lateral scapular winging and atrophy of the trapezius and sternocleidomastoid muscles. Electrophysiological studies demonstrated motor unit preservation; therefore, surgical exploration, styloidectomy, and SAN decompression were performed through a transcervical approach. Postoperatively, both patients had improvements in pain and shoulder mobility, the return of muscle strength, and electrophysiological evidence of trapezius reinnervation. LESSONS: Compression of the SAN, which can be identified both clinically and on electrodiagnostic testing, is an atypical finding that can result from a posteriorly angulated or calcified styloid process. This winged variant of ES should be included in the differential for SAN palsy, and a multidisciplinary approach is recommended for assessment and management.

Lateral Displacement of the Phrenic Nerve in C5 Tumors.

BACKGROUND AND OBJECTIVES: Nerve sheath tumors of the brachial plexus frequently distort the local anatomy, increasing the difficulty of safe exposure and resection. However, lateral displacement of the phrenic nerve has not been previously described. The purpose of this study was thus to illustrate the abnormal lateral displacement of the phrenic nerve in 2 cases of patients undergoing brachial plexus tumor resection and provide a possible mechanism for this observation. METHODS: Two patients underwent surgical resection of clinically progressing C5 schwannomas. During exposure, the phrenic nerve was found to be significantly more superficial and lateral than typical. This structural relationship persisted even after complete resection of the lesion. Both patients did well postoperatively. RESULTS: The phrenic nerve traverses along the anterolateral aspect of the anterior scalene. However, in these 2 cases of C5 nerve sheath tumors, the phrenic was found to be significantly more lateral and superficial than usual, draping across the medial aspect of the tumor. We believe that the C5-phrenic communicating branch may act as a functional tether that mobilizes the phrenic nerve laterally as the tumor grows. The mass effect on the anterior scalene by the underlying C5 tumor may further contribute to the anterolateral and superficial displacement of the nerve. CONCLUSION: The phrenic nerve may be seen markedly more laterally and superficially displaced in cases of C5 nerve sheath tumors. It is important for surgeons who operate on lesions of the brachial plexus to be aware of this phenomenon.

Tibial intraneural ganglion cysts arising from the tibiofemoral joint: illustrative cases.

BACKGROUND: Intraneural cysts involving the tibial nerve in the knee region (popliteal fossa) are rare. According to the articular (synovial) theory, which posits a joint origin for this pathology, these cysts originate from either the superior tibiofibular joint (STFJ) or the tibiofemoral (knee) joint. As tibial intraneural cysts arising from the tibiofemoral joint remain poorly understood, the authors present 2 illustrative cases and a review of the world's literature on all tibial intraneural ganglion cysts in the knee region. OBSERVATIONS: Fourteen cases of tibial intraneural ganglion cysts arising from the tibiofemoral joint were identified in the literature. Different articular branch patterns were demonstrated, which could be explained by the varied, rich articular branch innervation at the knee. Favorable outcomes were observed in cases in which the articular branch had been disconnected and the cyst drained and were comparable to the outcomes seen in tibial intraneural ganglion cysts with an STFJ origin. LESSONS: Tibial intraneural cysts in the knee region can be subdivided by their joint of origin: the STFJ or the tibiofemoral joint. Those arising from the tibiofemoral joint originate from different areas of the joint and propagate in predictable patterns, with favorable outcomes following surgical intervention when the joint connection is identified and treated. The origin of tibial intraneural cysts from the tibiofemoral joint are more complex than those originating from the STFJ but seem to have similar propagation patterns and outcomes.

Selective upper trunk posterior division fascicular nerve transfer for proximal spinal accessory neuropathy: illustrative case.

BACKGROUND: Spinal accessory nerve palsy can lead to severe shoulder pain and weakness, lateral scapular winging, and limitations in overhead activity. It most often occurs because of iatrogenic injury from procedures within the posterior triangle of the neck. OBSERVATIONS: The authors present the case of a 39-year-old male with symptoms of right shoulder weakness and neck pain after a total thyroidectomy and right neck dissection. With ultrasound findings of a neuroma-in-continuity but no clinical or electromyographic signs of reinnervation at 6 months, surgical intervention was indicated. Operative exploration confirmed a very proximal injury and nonconducting neuroma-in-continuity of the spinal accessory nerve. A selective distal nerve transfer from the posterior division of the upper trunk was performed. At the 2.5-year follow-up, the patient demonstrated excellent recovery of full active shoulder abduction and forward flexion, return to full-time employment, and mild residual scapular winging. LESSONS: Distal nerve transfers should be considered in cases of late presentation when primary repair is not possible or long interpositional grafts are required. Selective fascicular transfer from the posterior division of the upper trunk provides the advantages of a single incision, short reinnervation time, and synergistic donor function to facilitate motor reeducation.

Triceps-to-Biceps Tendon Transfer for Restoration of Elbow Flexion in Brachial Plexus Injury.

PURPOSE: Restoring elbow flexion is a reconstructive priority in patients with brachial plexus injuries. This study aimed to evaluate the results and assess factors contributing to outcomes of triceps-to-biceps tendon transfer in patients presenting with delayed or chronic upper brachial plexus injury. METHODS: Patients with traumatic brachial plexus injuries undergoing triceps-to-biceps tendon transfer at a single institution's multidisciplinary brachial plexus center between 2001 and 2021 were retrospectively reviewed. The entire triceps tendon was transferred around the lateral aspect of the arm, secured to the radius with a tenodesis button, and reinforced with a side-to-side tendon transfer to the biceps tendon. Primary outcomes include the modified British Medical Research Council (mBMRC) elbow flexion strength and active elbow range of motion. RESULTS: Twelve patients (eight men and four women; mean age, 45.2 years) were included. The mean follow-up was 10.4 (range, 5-34) months. Nine patients achieved mBMRC ≥3. Five patients achieved mBMRC 4. Average active elbow flexion was 119°, with average extension deficit of 11°. There were three patients with unsatisfactory results, achieving mBMRC 2 elbow flexion. CONCLUSIONS: Triceps-to-biceps tendon transfer is an excellent tendon transfer option for restoring elbow flexion in certain patients with an adequately functioning triceps muscle, who present with a delayed or chronic brachial plexus injury. Although most patients achieved mBMRC ≥3 elbow flexion, there was an expected permanent loss of elbow active extension with a residual elbow flexion contracture. LEVEL OF EVIDENCE: Therapeutic IV.

Clinical Predictors of C5 Spinal Nerve Viability in Pan-Brachial Plexus Injuries.

BACKGROUNDS: In pan-brachial plexus injury patients, distinguishing between pre-ganglionic and post-ganglionic injuries is crucial to reconstructive planning. This study aimed to identify pre-operative factors that would accurately predict a reconstructible C5 spinal nerve. METHODS: Pan-brachial plexus injury patients from a single institution between 2001 and 2018 were reviewed. Patient demographics, clinical examination, diagnostic imaging, and electrodiagnostic results were recorded. C5 viability was determined based on supraclavicular exploration and intraoperative electrophysiologic testing. Univariate analysis identified significant factors for regression analysis. Multivariable parsimonious model was created using stepwise high performance logistic regression. RESULTS: 311 patients (mean age 29.9 years; 46 females, 265 males; Injury Severity Score 17.2) were included. 134 (43%) had a viable C5 and 50 (12%) patients had a viable C6 nerve. Intact C5 spinal nerve on CT myelogram (OR 5.4), positive Tinel's test (OR 2.6), M ≥ 4 rhomboid (OR 1.3) or M ≥ 4 serratus anterior (OR 1.4), and rhomboid needle EMG (OR 1.8) were predictive of having a viable C5 spinal nerve. The multivariable parsimonious stepwise model (AUC 0.77) included four factors: positive Tinel's test, intact C5 spinal nerve on CT myelogram, hemi-diaphragmatic elevation, and mid-cervical paraspinal fibrillations. CONCLUSIONS: In this cohort of pan-brachial plexus patients with major polytrauma, there was a 43% incidence of viable C5 spinal nerve. A positive Tinel's test (OR 2.1) and intact C5 spinal nerve on CT myelogram (OR 4.9) predicted a viable C5 nerve. In contrast, hemi-diaphragmatic elevation (OR 3.1) and mid-cervical paraspinal fibrillations (OR 2.92) predicted root avulsion.

Optimal Distal Tendon Insertion Point for Elbow Flexion in Free-Functioning Gracilis Muscle Transfer for Panbrachial Plexus Injuries: A Cadaveric Study.

PURPOSE: Following pan-brachial plexus injuries, restoration of elbow flexion is widely accepted as the reconstructive priority. A gracilis free functioning muscle transfer (FFMT) can be used to restore elbow flexion alone with insertion into the biceps brachii (BIC) or brachioradialis (BRD) tendons or restore combined elbow and finger flexion with a more distal insertion into the flexor digitorum profundus (FDP) tendons. Using cadaveric experiments, we determined the peak instantaneous moment arm for each insertion option. METHODS: Six simulated gracilis transfer surgeries were performed using both arms of three fresh-frozen full body cadaveric specimens (age: 79 + 10 years. 2 female). The gracilis muscles from both legs were harvested and transferred to the contralateral upper extremity. The elbow was manually moved through three flexion-extension cycles while the instantaneous moment arm was calculated from measurements of gracilis excursion and elbow joint angle for the three distal insertion sites. RESULTS: Peak instantaneous moment arm for all three insertions occurred at an elbow angle between 83° to 92° with a magnitude ranging from 33 mm to 54 mm. The more distal (FDP/BRD) insertions produced a significantly greater (∼1.5 times) peak elbow flexion instantaneous moment arm compared to the BIC insertion. CONCLUSIONS: Based on the instantaneous moment arm, the gracilis FFMT distal insertion locations could result in greater reconstructed elbow flexion strength. In addition, direct measurement of the shape and magnitude of the moment arm curve for differing insertion sites allows high resolution surgical planning and model testing. CLINICAL RELEVANCE: This study presents the first direct experimental quantification of the gracilis FFMT instantaneous moment arm. The experimental evidence supports the use of FDP/BRD insertion locations by providing a quantitative explanation for the increased elbow flexion torque observed clinically in patients with a gracilis FFMT and distal FDP insertion.

Chronic Polymicrobial Infectious Melanonychia Striata.

CASE: A 62-year-old man presented with a 10-year history of isolated melanonychia striata of his dominant thumb. Surgical biopsy ruled out subungual melanoma but revealed foreign plant material causing chronic infectious melanonychia from multiple pathogens, including Pseudomonas aeruginosa, Escherichia coli, and Candida spp. After removal of the nail plate and thorough debridement, the melanonychial streak resolved completely at 12 months of follow-up. CONCLUSION: Bacterial infection is a rarely reported cause of melanonychia, and in addition to surgical pathologic specimens, intraoperative fungal and bacterial cultures should always be obtained for accurate diagnosis of melanonychia striata.

Characterizing peroneal nerve injury clinicoradiological patterns with MRI in patients with sciatic neuropathy and foot drop after total hip replacement.

OBJECTIVE: Sciatic nerve injury following total hip arthroplasty (THA) predominantly affects the peroneal division of the sciatic nerve, often causing a foot drop. This can result from a focal etiology (hardware malposition, prominent screw, or postoperative hematoma) or nonfocal/traction injury. The objective of this study was to compare the clinicoradiological features and define the extent of nerve injury resulting from these two distinct mechanisms. METHODS: Patients who developed a postoperative foot drop within 1 year after primary or revision THA with a confirmed proximal sciatic neuropathy based on MRI or electrodiagnostic studies were retrospectively reviewed. Patients were divided into two cohorts: group 1 (focal injury), including patients with an identifiable focal structural etiology, and group 2 (nonfocal injury), including patients with a presumed traction injury. Patient demographics, clinical examinations, subsequent surgeries, electrodiagnostic study results, and MRI abnormalities were noted. The Student t-test was used to compare time to onset of foot drop and time to secondary surgery. RESULTS: Twenty-one patients, treated by one surgeon, met inclusion criteria (8 men and 13 women; 14 primary THAs and 7 revision THAs). Group 1 had a significantly longer time from THA to the onset of foot drop, with a mean of 2 months, compared with an immediate postoperative onset in group 2 (p = 0.02). Group 1 had a consistent pattern of localized focal nerve abnormality on imaging. In contrast, the majority of patients in group 2 (n = 11) had a long, continuous segment of abnormal size and signal intensity of the nerve, while the other 3 patients had a segment of less abnormal nerve in the midthigh on imaging. All patients with a long continuous lesion had Medical Research Council grade 0 dorsiflexion prior to secondary nerve surgeries compared with 1 of 3 patients with a more normal midsegment. CONCLUSIONS: There are distinct clinicoradiological findings in patients with sciatic injuries resulting from a focal structural etiology versus a traction injury. While there are discrete localized changes in patients with a focal etiology, those with traction injuries demonstrate a diffuse zone of abnormality within the sciatic nerve. A proposed mechanism involves anatomical tether points of the nerve acting as points of origin and propagation for traction injuries, resulting in an immediate postoperative foot drop. In contrast, patients with a focal etiology have localized imaging findings but a highly variable time to the onset of foot drop.

Anterior Interosseus to Ulnar Motor Nerve Transfers: A Canadian Perspective.

BACKGROUND: The anterior interosseus nerve (AIN) to ulnar motor nerve transfer has been popularized as an adjunct to surgical decompression in patients with severe cubital tunnel syndrome (CuTS) and high ulnar nerve injuries. The factors influencing its implementation in Canada have yet to be described. METHODS: An electronic survey was distributed to all members of the Canadian Society of Plastic Surgery (CSPS) using REDCap software. The survey examined 4 themes: previous training/experience, practice volume of nerve pathologies, experience with nerve transfers, and approach to the treatment of CuTS and high ulnar nerve injuries. RESULTS: A total of 49 responses were collected (12% response rate). Of all, 62% of surgeons would use an AIN to ulnar motor supercharge end-to-side (SETS) transfer for a high ulnar nerve injury. For patients with CuTS and signs of intrinsic atrophy, 75% of surgeons would add an AIN-SETS transfer to a cubital tunnel decompression. Sixty-five percent would also release Guyon's canal, and the majority (56%) use a perineurial window for their end-to-side repair. Eighteen percent of surgeons did not believe the transfer would improve outcomes, 3% cited lack of training, and 3% would preferentially use tendon transfers. Surgeons with hand fellowship training and those less than 30 years in practice were more likely to use nerve transfers in the treatment of CuTS (P < .05). CONCLUSIONS: Most CSPS members would use an AIN-SETS transfer in the treatment of both a high ulnar nerve injury and severe CuTS with intrinsic atrophy.

Radial nerve myofibroma: a rare benign tumor with perineural infiltration. Illustrative case.

BACKGROUND: Myofibromas are benign mesenchymal tumors, classically presenting in infants and young children in the head and neck region. Perineural involvement, especially in peripheral nerves within the upper extremity, is extremely rare in myofibromas. OBSERVATIONS: The authors present the case of a 16-year-old male with a 4-month history of an enlarging forearm mass and rapidly progressive dense motor weakness in wrist, finger, and thumb extension. Preoperative imaging and fine needle biopsy confirmed the diagnosis of a benign isolated myofibroma. Given the dense paralysis, operative management was indicated, and intraoperative exploration showed extensive involvement of tumor within the radial nerve. The infiltrated nerve segment was excised along with the tumor, and the resulting 5-cm nerve gap was reconstructed using autologous cabled grafts. LESSONS: Perineural pseudoinvasion can be an extremely rare and atypical feature of nonmalignancies, resulting in dense motor weakness. Extensive nerve involvement may still necessitate nerve resection and reconstruction, despite the benign etiology of the lesion.

Diagnostic value of proximal cutaneous nerve biopsy in brachial and lumbosacral plexus pathologies.

BACKGROUND: Brachial and lumbosacral plexopathies can result from numerous non-traumatic etiologies, including those of inflammatory, autoimmune, or neoplastic origin, that often require nerve biopsy for diagnosis. The purpose of this study was to evaluate the diagnostic efficacy of medial antebrachial cutaneous nerve (MABC) and posterior femoral cutaneous nerve (PFCN) nerve biopsies in proximal brachial and lumbosacral plexus pathology. METHOD: Patients undergoing MABC or PFCN nerve biopsies at a single institution were reviewed. Patient demographics, clinical diagnosis, symptom duration, intraoperative findings, post-operative complications, and pathology results were recorded. Biopsy results were classified as diagnostic, inconclusive, or negative based on the final pathology. RESULTS: Thirty patients undergoing MABC biopsies in the proximal arm or axilla and five patients with PFCN biopsies in the thigh or buttock were included. MABC biopsies were diagnostic in 70% of cases overall and 85% diagnostic in cases where pre-operative MRI also demonstrated abnormalities in the MABC. PFCN biopsies were diagnostic in 60% of cases overall and in 100% of patients with abnormal pre-operative MRIs. There were no biopsy-related post-operative complications in either group. CONCLUSIONS: In diagnosing non-traumatic etiologies of brachial and lumbosacral plexopathies, proximal biopsies of the MABC and PFCN provide high diagnostic value with low donor morbidity.

Strength Comparison of Fibrin Glue and Suture Constructs in Upper Extremity Peripheral Nerve Coaptations: An In Vitro Study.

PURPOSE: To compare in vitro failure loads of nerve coaptations using fibrin glue alone, a suture alone, and a combination of fibrin glue and a suture. METHODS: The median, radial, and ulnar nerves of 15 fresh-frozen cadaveric upper extremity specimens (45 nerves in total) were dissected in vitro and transected 5 cm proximal to the wrist crease to simulate an injury requiring coaptation. Three coaptation techniques were used: fibrin glue alone, a suture alone, and a suture augmented with fibrin glue. The load to failure of each repair was measured using a linear servo-actuator with an in-line force sensor. The results were analyzed using 2-way repeated measures analysis of variance tests and pairwise comparisons with Bonferroni correction. RESULTS: Both the nerve coaptation technique and the specific nerve that was repaired had a significant effect on failure load. Suture-glue repair had the highest load to failure, 11.2 ± 2.9 N, and significantly increased the load to failure by 2.9 ± 1.7 N compared with glue repair alone. There was no significant difference between suture-glue repair and suture repair alone or between glue repair alone and suture repair alone. CONCLUSIONS: In this in vitro cadaveric model, nerve injury coaptation using both a suture and fibrin glue resulted in the strongest repair. The addition of fibrin glue may provide some benefit when used to augment suture repair, but when used in isolation, it is inferior to combined suture-and-glue constructs. CLINICAL RELEVANCE: Combined suture-and-glue nerve coaptations might be useful in the early postoperative period in increasing nerve repair strength and potentially reducing rupture rates.