A favourable suture method for size-mismatched nerve transfer: a case series of intercostal-to-musculocutaneous nerve transfer for brachial plexus injury.

We review a nerve suture method for size-mismatched nerve transfers and report a case series involving patients with brachial plexus injury who underwent intercostal-to-musculocutaneous nerve transfer using this method.

The utility of selective partial neurectomy of the musculocutaneous nerve in children with bilateral spastic elbow.

PURPOSE: This study aims to determine the utility of selective partial neurectomy of the musculocutaneous nerve (MCN) in pediatric patients with bilateral spastic elbow. METHODS: A prospective, cross-sectional, case series study was performed in nine pediatric patients (four females and five males) with bilateral spastic elbow, all with a 11.4-year-old average age, where 18 selective partial neurectomies of the MCN were carried out. They were evaluated with goniometry of both spastic elbows at resting position and active amplitude, and staging spasticity employing the Modified Ashworth Scale (MAS) in the preoperative and postoperative period. The results are reported 1 year after surgery. RESULTS: The etiology of the spasticity was secondary to cerebral palsy in eight patients (88.8%) and in one patient (11.11%) secondary to traumatic brain injury. A clinical improvement was observed in goniometry comparing the preoperative and postoperative resting position, a mean preoperative of 44.38 degrees (SD ± 7.61) versus 98.05 degrees (SD ± 24.44), respectively, and preoperative active amplitude a mean of 86.55 degrees (SD ± 15.97) versus the mean postoperative of 47.33 (SD ± 17.86). A relevant decrease on the MAS after surgical intervention was observed, resulting from an average preoperative state according to MAS of 3.78 (SD ± 0.42) to a postoperative state according to MAS of 1.44 (SD ± 0.51), these changes being statistically significant (p ≤ 0.001). No postoperative complications were observed. CONCLUSIONS: Selective partial neurectomy of the MCN has shown good results in patients with bilateral spastic elbow in whom antispastic drugs and physical therapy have failed, and has prove permanent effects.

Restoring musculocutaneous nerve function in 146 brachial plexus operations - A retrospective analysis.

INTRODUCTION: A brachial plexus lesion is a devastating injury often affecting young, male adults after traffic accidents. Therefore, surgical restoration of elbow flexion is critical for establishing antigravity movement of the upper extremity. We analyzed different methods for musculocutaneous reconstruction regarding outcome. METHODS: We conducted a retrospective analysis of 146 brachial plexus surgeries with musculocutaneous reconstruction performed at our department from 2013 to 2017. Demographic data, surgical method, donor and graft nerve characteristics, body mass index (BMI) as well as functional outcome of biceps muscle based on medical research council (MRC) strength grades before and after surgery were analyzed. Multivariate analysis was performed using SPSS. RESULTS: Oberlin reconstruction was the procedure performed most often (34.2%, n = 50). Nerve transfer and autologous repair showed no significant differences regarding outcome (p = 0.599, OR 0.644 CI95% 0.126-3.307). In case of nerve transfers, we found no significant difference whether reconstruction was performed with or without a nerve graft (e.g. sural nerve) (p = 0.277, OR 0.619 CI95% 0.261-1.469). Multivariate analysis identifies patient age as a strong predictor for outcome, univariate analysis indicates that nerve graft length > 15 cm and BMI of > 25 could lead to inferior outcome. When patients with early recovery (n = 19) are included into final evaluation after 24 months, the general success rate of reconstructions is 62,7% (52/83). CONCLUSION: Reconstruction of musculocutaneous nerve after brachial plexus injury results in a high rate of clinical improvement. Nerve transfer and autologous reconstruction both show similar results. Young age was confirmed as an independent predictor for better clinical outcome. Prospective multicenter studies are needed to further clarify.

The Effectiveness of Different Nerve Transfers in the Restoration of Elbow Flexion in Adults Following Brachial Plexus Injury: A Systematic Review and Meta-Analysis.

PURPOSE: Restoration of elbow flexion is an important goal in the treatment of patients with traumatic brachial plexus injury. Numerous studies have described various nerve transfers for neurotization of the musculocutaneous nerve (or its motor branches); however, there is uncertainty over the effectiveness of each method. The aim of this study was to summarize the published evidence in adults with traumatic brachial plexus injury. METHODS: Medline, Embase, medRxiv, and bioRxiv were systematically searched from inception to April 12, 2021. We included studies that reported the outcomes of nerve transfers for the restoration of elbow flexion in adults. The primary outcome was elbow flexion of grade 4 (M4) or higher on the British Medical Research Council scale. Data were pooled using random-effects meta-analyses, and heterogeneity was explored using metaregression. Confidence intervals (CIs) were generated to the 95% level. RESULTS: We included 64 articles, which described 13 different nerve transfers. There were 1,335 adults, of whom 813 (61%) had partial and 522 (39%) had pan-plexus injuries. Overall, 75% of the patients with partial brachial plexus injuries achieved ≥M4 (CI, 69%-80%), and the choice of donor nerve was associated with clinically meaningful differences in the outcome. Of the patients with pan-plexus injuries, 45% achieved ≥M4 (CI, 31%-60%), and overall, each month delay from the time of injury to reconstruction reduced the probability of achieving ≥M4 by 7% (CI, 1%-12%). CONCLUSIONS: The choice of donor nerve affects the chance of attaining a British Medical Research Council score of ≥4 in upper-trunk reconstruction. For patients with pan-plexus injuries, delay in neurotization may be detrimental to motor outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

"Undercutting of the corresponding rib": a novel technique of increasing the length of donor in intercostal to musculocutaneous nerve transfer in brachial plexus injury.

Intercostal nerves (ICN) are often utilized as donors for various neurotization procedures in brachial plexus injuries. ICN to musculocutaneous nerve (MCN) transfer is usually a standard in pan brachial plexus injuries, in order to restore flexion at the elbow. A tensionless co-aptation of the donor-recipient nerves often necessitates either a distal dissection of the ICNs where the number of fascicles is rather low or a proximal dissection, often at the cost of dissection of the serratus anterior digitation with a risk of later fibrosis and adhesion. We report two cases of pan brachial plexus injuries where ICN-MCN transfer was performed to restore elbow function. These patients underwent clinical and electrodiagnostic evaluation before surgery. We used the standard technique of harvesting ICNs 3-5, with our technical modification of "undercutting of rib" for increasing the donor length. The procedure was applied in two patients with pan brachial plexus injury (mean age = 23). Mean duration since the injury to surgery was ten months. Both patients underwent tensionless anastomosis with a combination of suture and fibrin glue co-aptation. While one patient had some improvement in elbow flexion, another one was under active rehabilitation protocol during follow-up. We found that undercutting of the ribs near serratus digitations can allow mobilization of the ICN from its groove, which in turn lengthens the donor nerve length without violating the serratus anterior digitations and without too anterior dissection of the nerve. It can be a viable option when a tensionless co-aptation at the axilla is otherwise not feasible intraoperatively.

Anatomic Variations of the Musculocutaneous Nerve and Clinical Implications for Restoration of Elbow Flexion.

PURPOSE: The restoration of elbow flexion is of primary importance in the management of patients with brachial plexus injuries. Superior functional outcomes via fascicle transfer from the ulnar and median nerves have resulted in this transfer being considered the mainstay of recovery of elbow flexion in patients with intact C8 and T1 function. An understanding of the anatomy of the musculocutaneous nerve (MCN) and its branching pattern is key while performing these transfers. METHODS: A prospective cohort study was conducted in patients who underwent nerve transfer for the restoration of elbow flexion following a traumatic brachial plexus injury. The anatomic course and branching pattern of the MCN were recorded in eligible cases, both as a line diagram and using intraoperative photographs. RESULTS: One hundred fifty patients underwent nerve transfer for the restoration of elbow flexion following an injury to the brachial plexus. The MCN in 138 patients (92%) was found to pierce the coracobrachialis muscle before emerging lateral to it. One hundred thirty-four patients (89.3%) demonstrated the "classical" anatomy. One hundred fifteen patients (76.6%) had a single primary branch to the biceps, whereas 25 patients (16.6%) demonstrated a discrete motor branch to each head. One hundred thirty-three dissections (88.6%) revealed a single muscular branch to the brachialis arising posteromedially from the MCN, distal to the origin of the branch to the biceps brachii. Notable unreported variations, such as the MCN penetrating the biceps as it descended, multiple brachialis branches, and trifurcation of divisions of the MCN, were documented. CONCLUSIONS: Variations in MCN anatomy are quite common, and even unreported variations can be encountered. CLINICAL RELEVANCE: Exploration of the MCN and its branches for nerve transfers requires knowledge of these anatomic variations and vigilance to prevent inadvertent injuries while dissecting them for nerve transfer surgery.

[Modification of intercostobrachial neurotization of musculocutaneous and axillary nerves in total brachial plexopathy: description of technique and literature review]. / Modifikatsiya interkostobrakhial'noi nevrotizatsii myshechno-kozhnogo i podmyshechnogo nervov pri total'noi brakhiopleksopatii: opisanie metodiki i obzor literatury.

BACKGROUND: Intercostobrachial neurotization is one of the few approach for partial motor recovery of extremity in patients with total trauma of brachial plexus. However, direct coaptation with musculocutaneous nerve is often impossible due to different anatomy of intercostal nerves and their functional failure at several levels. This necessitates the use of intermediate graft that deteriorates the final outcome. OBJECTIVE: To develop an alternative method for direct coaptation of musculocutaneous nerve with insufficiently long intercostal donor nerves. MATERIAL AND METHODS: The study included 26 patients with total post-traumatic plexitis. All patients underwent intercostobrachial neurotization of musculocutaneous and axillary nerves. Original technique of direct selective neurotization of motor fascicular groups of musculocutaneous and axillary nerves was used in 11 cases. RESULTS AND DISCUSSION: A modified variant of intercostobrachial neurotization of musculocutaneous and axillary nerves consists in mobilization and transposition of recipient nerves in axillary region. This makes it possible to reduce the distance to donor nerves and, in most cases, to carry out direct neurotization without autologous grafts. Among 11 patients, restoration of shoulder abduction and elbow flexion was obtained in 7 patients (77 %). CONCLUSION: The proposed adaptive technique makes it possible to avoid graft lengthening in some cases and provides satisfactory results.

Acellular nerve graft enriched with mesenchymal stem cells in the transfer of the phrenic nerve to the musculocutaneous nerve in a C5-C6 brachial plexus avulsion in a rat model.

INTRODUCTION: Phrenic nerve transfer has been shown to achieve good nerve regeneration in brachial plexus avulsion. Acellular nerve allografts (ANAs) showed inferior results to autografts, which is why its use with mesenchymal stem cells (MSCs) is currently being studied. The aim is to study the effect of BM-MSCs associated with ANAs in a rat model of phrenic nerve transfer to the musculocutaneous nerve in a C5-C6 avulsion. MATERIAL AND METHODS: 42 Wistar-Lewis rats underwent a C5-C6 lesion in the right forelimb by excising a 3 mm segment from both roots, followed by a phrenic nerve transfer to the musculocutaneous nerve associated with the interposition of a three types of nerve graft (randomly distributed): control (autograft) group (n = 12), ANAs group (n = 12), and ANAs + BM-MSCs group (n = 18) After 12 weeks, amplitude and latency of the NAP and the compound motor action potential (CMAP) were measured. Biceps muscles were studied by histological analysis and nerve grafts by electron microscopy and fluorescence analysis. RESULTS: Statistically significant reductions were found in latency of the CMAP between groups control (2.48 ± 0.47 ms) and experimental (ANAs: 4.38 ± 0.78 ms, ANAs + BM-MSCs: 4.08 ± 0.85 ms) and increases in the amplitude of the CMAP between groups control (0.04388 ± 0.02 V) and ANAs + BM-MSCs (0.02275 ± 0.02 V), as well as in the thickness of the myelin sheath between groups control (0.81 ± 0.07 µm) and experimental (ANAs: 0.72 ± 0.08 µm, ANAs + BM-MSCs: 0.72 ± 0.07 µm) and in the area of the myelin sheath between groups control (13.09 ± 2.67 µm2 ) and ANAs (10.01 ± 2.97 µm2 ) (p < .05). No statistically significant differences have been found between groups ANAs and ANAs + BM-MSCs. CONCLUSIONS: This study presents a model for the study of lesions of the upper trunk and validates the autologous graft as the gold standard.

Nerve Transfer of Brachialis Branch to Anterior Interosseus Nerve Using In Situ Lateral Antebrachial Cutaneous Nerve Graft in Tetraplegia.

PURPOSE: Reconstruction of finger motion is a therapeutic goal in tetraplegic patients. Although nerve transfer of the brachialis branch of the musculocutaneous nerve to the anterior interosseus nerve has been previously described, this results in unreliable reinnervation because the donor nerve is proximal to the target muscle. We describe an alternative technique in which nerve transfer is performed using the lateral antebrachial cutaneous nerve as a vascular in situ nerve graft. The clinical results are reported. METHODS: Nine upper limbs of 6 patients (mean age 25 years) with tetraplegia were subjected to brachialis-to-anterior interosseus nerve transfer using the lateral antebrachial cutaneous nerve as a vascular in situ nerve graft, at a mean of 6 months after injury. Additional supinator branch transfer to the posterior interosseous nerve was performed for 6 upper limbs and to the flexor digitorum superficialis motor branch for 1 upper limb. RESULTS: At a mean of 2 years of follow-up, thumb and finger flexion strength scored M3-M4 in 5 of the 9 limbs according to the Medical Research Council scale. Key pinch and grip pinch averaged 0.6 kg (range, 0-1.0 kg) and 2.2 kg (range, 0-8 kg), respectively. No donor-site deficit was observed. CONCLUSIONS: Brachialis-to-anterior interosseus nerve transfer with an in situ lateral antebrachial cutaneous nerve graft can be used to reconstruct thumb and finger flexion in tetraplegic patients. Combined with supinator-to- posterior interosseous nerve transfer, simultaneous active extension of the fingers can be achieved. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic V.

Feasibility of Medial Pectoral Nerve to Musculocutaneous Nerve Transfer Using Medial Antebrachial Cutaneous Nerve of Forearm Graft: Histopathologic and Anatomical Evaluation.

AIM: To evaluate the compatibility of medial antebrachial cutaneous nerve of the forearm (MACN) with medial pectoral (MPN) and musculocutaneous (MCN) nerves for the anastomosis from anatomical and histopathologic aspects. MATERIAL AND METHODS: Ten brachial plexus specimens from five cadavers were dissected. The distances of the distal ends of MPN and MACN and proximal ends of MACN and MCN were measured from coracoid. Histopathologic slides from the four mentioned nerve ends were provided. The number of fascicles, cross-section diameter, and area of each nerve ends were measured. RESULTS: The distance of proximal and distal ends of MACN were adjacent to MPN and MCN. The mean number of fascicles (4.5 ± 1.2 vs. 2.9 ± 1.0), area (6.0 ± 2.5 vs. 2.8 ± 2.4) and diameter (2.7 ± 0.6 vs. 1.8 ± 0.7) of the distal end of MACN was significantly more than MCN. The mean number of fascicles (4.4 ± 1.4 vs. 2.6 ± 0.5), area (5.6 ± 2.4 vs. 2.0 ± 1.0) and diameter (2.6 ± 0.6 vs. 1.6 ± 0.4) of the proximal end of MACN was significantly more than MPN. The mentioned parameters were similar between MCN and MPN. CONCLUSION: Our study reveals that MACN is not a proper graft for MCN and MCN anastomosis due to the incompatibility of its diameter, area, and number of fascicles.

Long Thoracic Nerve Transfer for Children With Brachial Plexus Injuries.

INTRODUCTION: The transfer of intraplexal and extraplexal nerves for restoration of function in children with traumatic and birth brachial plexus palsies has become well accepted. Little has been written about using the long thoracic nerve (LTN) as a donor in reanimation of the upper extremity. The authors present a case series of nerve transfers using the LTN as a donor in brachial plexus injury. METHODS: A retrospective chart review was performed over a 10-year period at a single institution. The primary outcome measure was the active movement scale. RESULTS: Fourteen patients were included in the study: 10 birth injury patients and 4 blunt trauma patients. Average follow-up time was 21.3 and 10.75 months, respectively. The best outcomes were seen when the LTN was used for reinnervation of the obturator nerve in free functioning muscle transfers. The next most successful recipients were the musculocutaneous and axillary nerves. Outcomes were poor in transfers to the posterior interosseous fascicles of the radial nerve and the radial nerve branches to the triceps. DISCUSSION: The LTN may be a potential nerve donor for musculocutaneous or axillary nerve reinnervation in patients with brachial plexus injuries when other donors are not available during a primary plexus reconstruction. However, the best use may be for delayed neurotization of a free functioning muscle transfer after the initial plexus reconstruction has failed and no other donors are available. LEVEL OF EVIDENCE: Level IV-therapeutic study.

The results of decompression of the musculocutaneous nerve entrapment in children with obstetric brachial plexus palsy.

PURPOSE: Elbow flexion is a key indicator of functional recovery in obstetric brachial plexus palsy (OBPP). However, lack of flexion could be a result of an entrapped musculocutaneous nerve during the healing period. The purpose of this study was to investigate the possible compression of the musculocutaneous nerve and outcomes of decompression. METHODS: The study included 11 children aged with a mean age of 10.9 ± 2.7 months (range, 8-16 months) with Narakas 2 involvement OBPP, who had insufficient elbow flexion but had satisfactory shoulder abduction. Prior to surgery, magnetic resonance imaging (MRI) was performed to identify the entrapment. The children were evaluated pre-operatively and at 3 and 12 months postoperatively using the Active Movement Scale and Faradic Excitability Test. The musculocutaneous nerve was explored and decompressed in all the children. Regular physiotherapy and a home exercise programme were prescribed after surgery. RESULTS: The MRI findings were consistent with the surgical exploration in all the infants. Statistical analyses showed that decompression of the musculoskeletal nerve improved active movement scale scores on elbow flexion and faradic excitability test values of biceps brachii within 3 months after surgery. CONCLUSION: Children with delayed elbow flexion and satisfactory shoulder abduction may have an entrapped musculocutaneous nerve in the proximal arm and decompression of the nerve improves elbow function.

Elbow Flexion Reconstruction in Brachial Plexus Avulsion Injuries - Results with Intercostal Nerve and Distal Nerve Transfers.

Background: The neural surgical options for reconstruction of elbow flexion in brachial plexus injuries depend on the availability of nerve donors. In upper-type avulsion injuries, the ulnar or median nerves, when intact, are reliable intra-plexal donor nerves for transfers to the biceps muscle. In complete avulsion injuries, donors are limited to extra-plexal sources, such as intercostal nerves (ICNs). Methods: We reviewed our results of ICN and partial distal nerve (ulnar or median) transfers for elbow flexion reconstruction in patients with brachial plexus avulsion injuries. The time taken for recovery of elbow flexion strength to M3 and the final motor outcome at 2 years were compared between both groups. Results: 38 patients were included in this study. 27 had ICN transfers to the musculocutaneous nerve (MCN), 8 had partial ulnar nerve transfers and 3 had partial median nerve transfers to the MCN's biceps motor branch. The mean time interval from injury to surgery was 3.6 months. Recovery of elbow flexion was observed earlier in the distal nerve transfer group (p < 0.05). Overall, success rates were higher in patients with distal nerve transfers (100%), compared to ICN transfers (63%) at 2 years (p = 0.018). Patients with distal nerve transfers achieved a higher final median strength of M4.0 [Interquartile range (IQR) 3.5-4.5], compared to M3.5 (IQR 2.0-4.0) in the ICN group (p = 0.031). In the subgroup of patients with upper-type brachial plexus injuries, there were no significant differences in motor outcomes between the ICN versus distal nerve transfers group. Conclusions: In our entire cohort, patients with distal nerve transfers had faster motor recovery and better elbow flexion power than patients with ICN transfers. In patients with partial brachial plexus injuries, outcomes of ICN transfers were not inferior to distal nerve transfers.

Intercostal to musculocutaneous nerve transfer in patients with complete traumatic brachial plexus injuries: case series.

BACKGROUND: To recover biceps strength in patients with complete brachial plexus injuries, the intercostal nerve can be transferred to the musculocutaneous nerve. The surgical results are very controversial, and most of the studies with good outcomes and large samples were carried out in Asiatic countries. The objective of the study was to evaluate biceps strength after intercostal nerve transfer in patients undergoing this procedure in a Western country hospital. METHODS: We retrospectively analyzed 39 patients from 2011 to 2016 with traumatic brachial plexus injuries receiving intercostal to musculocutaneous nerve transfer in a rehabilitation hospital. The biceps strength was graded using the British Medical Research Council (BMRC) scale. The variables reported and analyzed were age, the time between trauma and surgery, surgeon experience, body mass index, nerve receptor (biceps motor branch or musculocutaneous nerve), and the number of intercostal nerves transferred. Statistical tests, with a significance level of 5%, were used. RESULTS: Biceps strength recovery was graded ≥M3 in 19 patients (48.8%) and M4 in 15 patients (38.5%). There was no statistical association between biceps strength and the variables. The most frequent complication was a pleural rupture. CONCLUSIONS: Intercostal to musculocutaneous nerve transfer is a safe procedure. Still, biceps strength after surgery was ≥M3 in only 48.8% of the patients. Other donor nerve options should be considered, e.g., the phrenic or spinal accessory nerves.

Differences in strength fatigue when using different donors in traumatic brachial plexus injuries.

BACKGROUND: The purpose of this study was to assess the results of elbow flexion strength fatigue, rather than the maximal power of strength, after brachial plexus re-innervation with phrenic and spinal accessory nerves. We designed a simple but specific test to study whether statistical differences were observed among those two donor nerves. METHOD: We retrospectively reviewed patients with severe brachial plexus palsy for which either phrenic nerve (PN) or spinal accessory nerve (SAN) to musculocutaneous nerve (MCN) transfer was performed. A dynamometer was used to determine the maximal contraction strength. One and two kilograms circular weights were utilized to measure isometrically the duration of submaximal and near-maximal contraction time. Statistical analysis was performed between the two groups. RESULTS: Twenty-eight patients were included: 21 with a PN transfer while 7 with a SAN transfer for elbow flexion. The mean time from trauma to surgery was 7.1 months for spinal accessory nerve versus 5.2 for phrenic nerve, and the mean follow-up was 57.7 and 38.6 months, respectively. Statistical analysis showed a quicker fatigue for the PN, such that patients with the SAN transfer could hold weights of 1 kg and 2 kg for a mean of 91.0 and 61.6 s, respectively, while patients with transfer of the phrenic nerve could hold 1 kg and 2 kg weights for just a mean of 41.7 and 19.6 s, respectively. Both differences were statistically significant (at p = 0.006 and 0.011, respectively). Upon correlation analysis, endurances at 1 kg and 2 kg were strongly correlated, with r = 0.85 (p < 0.001). CONCLUSIONS: Our results suggest that phrenic to musculocutaneous nerve transfer showed an increased muscular fatigue when compared with spinal accessory nerve to musculocutaneous transfer. Further studies designed to analyze this relation should be performed to increase our knowledge about strength endurance/fatigue and muscle re-innervation.

Combined flexor carpi ulnaris and flexor carpi radialis transfer for restoring elbow function after brachial plexus injury.

The result of combined agonist and antagonist muscle innervation in traumatic brachial plexus injury through the intraplexal fascicle nerve transfers with the same donor function has not yet been reported. We describe a patient with a C5-C7 traumatic brachial plexus injury who had a combined transfer of the flexor carpi radialis (FCR) fascicle to the musculocutaneous nerve and the flexor carpi ulnaris (FCU) fascicle to the radial nerve of the triceps. The patient returned for his follow-up visit 2 years after his surgery. The muscle strengths of his triceps and biceps were Medical Research Council grade 2 and 0, respectively. Compared with his uninjured side, his grip strength was 9.8%, and his pinch strength was 14.2%. Our case report provides insights on result of combined agonist and antagonist muscle innervation through combining the motor fascicle of the FCR and FCU to restore the elbow flexor and extensor. The result may not be promising.