Musculocutaneous Research Articles

EMG Signs of Motor Units’ Enlargement in Stroke Survivors

The degeneration of lower motoneurons has often been reported in stroke survivors, with possible collateral reinnervation from the surviving motoneurons to the denervated muscle fibers. Under this assumption, a stroke would be expected to increase the size of motor units in paretic muscles. We indirectly address this issue with electrical stimulation and surface electromyography, asking whether stroke leads to greater variations in the amplitude of M waves elicited in paretic muscles than in contralateral, non-paretic muscles. Current pulses at progressively greater intensities were applied to the musculocutaneous nerve, stimulating motoneurons supplying the biceps brachii of eight stroke patients. The size of increases in the amplitude of M waves elicited consecutively, hereafter defined as increments, was considered to evaluate changes in the innervation ratio of biceps brachii motor units following stroke. Our findings showed that patients presented significantly (p = 0.016) greater increments in muscles of paretic than in non-paretic limbs. This result corroborates the notion that collateral reinnervation takes place after stroke, enlarging motor units’ size and the magnitude of the muscle responses. Therefore, the non-invasive analysis proposed here may be useful for health professionals to assess disease progression by tracking for neuromuscular changes likely associated with clinical outcomes in stroke survivors, such as in the muscles’ strength.

A rare bilateral variant of the coracobrachialis muscle with supernumerary heads and coexisted variant branching patterns of the brachial plexus and the axillary artery

PurposeThe study report describes a rare bilateral variant of a six- and five-headed coracobrachialis muscle (CB). The musculocutaneous nerve (MCN) (bilaterally) and the median nerve (MN) lateral root (unilaterally) pierced CB heads, separating superficial from deep heads.MethodsThe variant bilateral CB was identified in a 78-year-old formalin-embalmed male cadaver, derived from a body donation program after a signed informed consent.ResultsAt the right side: The 6-headed CB was pierced by the MCN, while the MN lateral root pierced the one superficial and deep head. CB was supplied by the lateral cord and the MCN. At the left side: A 5-headed CB was identified with three superficial distinct origins that fused into a common superficial head coursing anterior to MCN. The variant CB bilaterally (with 11 heads in total) coexisted with a MN variant formation, an atypical course of the MN lateral root through CB (right side), a connection of the MN lateral root with the MCN (left side) and a variant axillary artery branching pattern (bilaterally).ConclusionsCourse and direction of the accessory CB heads may occasionally entrap the MCN and/or adjacent structures (brachial artery and MN). The MCN compression results in problems in the glenohumeral joint flexion and adduction, and tingling or numbness of the elbow joint, the forearm lateral parts and the hand.

The Impact of Exercise on Motor Recovery after Long Nerve Grafting-Experimental Rat Study.

Long nerve grafting often results in unsatisfactory functional outcomes. In this study we aim to investigate the effect of swimming exercise on nerve regeneration and functional outcomes after long nerve grafting. A reversed long nerve graft was interposed between C6 and the musculocutaneous nerve in 40 rats. The rats were divided into four groups with 10 in each based on different postoperative swimming regimes for rehabilitation: group A, continuous exercise; group B, early exercise; group C, late exercise; and group D, no exercise (control group). A grooming test was assessed at 4, 8, 12, and 16 weeks postoperatively. Biceps muscle compound action potential (MCAP), muscle tetanic contraction force (MTCF), and muscle weights were assessed after 16 weeks. Histomorphometric analyses of the musculocutaneous nerves were performed to examine nerve regeneration. The grooming test showed all groups except group D demonstrated a trend of progressive improvement over the whole course of 16 weeks. Biceps MCAP, MTCF, and muscle weights all showed significant better results in the exercise group in comparison to the group D at 16 weeks, which is especially true in groups A and B. Nerve analysis at 16 weeks, however, showed no significant differences between the exercise groups and the control group. Swimming after long nerve grafting can significantly improve muscle functional behavior and volume. The effect is less evident on nerve regeneration. Continuous exercise and early exercise after surgery show more optimal outcomes than late or no exercise. Having a good habit with exercise in the early period is thought as the main reason. Further studies are needed to determine the optimal exercise regimen.

Safety-driven master’s technique of the Latarjet-Walch procedure and its short-term complications: experience in a study of 150 consecutive patients

Although the classic open Latarjet has a low recurrence rate in unstable shoulders, this advantage may be offset by the higher number of complications. We aimed to report the safety-driven nuanced steps and the resulting short-term complications of the Latarjet-Walch technique. Between 2016 and 2022, 150 patients who underwent the Latarjet procedure following the key safety-driven technical steps were retrospectively evaluated for intraoperative and short-term (3 months) complications. The complications were divided into 3 types: Any adverse event that did not need a change in the treatment protocol was a type 1 complication. An event that resulted in a prolongation of rehabilitation protocol or an additional medical line of treatment was classified as type 2, and an event that resulted in readmission, a resurgery, or one that affected the outcome was classified as a type 3 complication. There were 12 (8%) short-term complications in 9 patients. Neurological complications were noted in 3 (2%) patients (1 axillary nerve injury, 1 suprascapular nerve injury, and 1 musculocutaneous nerve injury). Type 1 complications were noted in 2 patients: 2 patients had hematoma that was detected as superficial swelling, but no surgical drainage was needed, and both resolved at their 1-month follow-up. Type 2 complications were noted in 4 patients. One patient had surgical site infection and a second patient had superficial wound dehiscence in the lower part of the wound. The third patient had suprascapular nerve paresis and the fourth had musculocutaneous nerve paresis and shoulder stiffness. Both nerve injuries recovered completely after 6 months of rehabilitation. Type 3 complications were noted in 3 patients. One patient had axillary nerve paresis and shoulder stiffness. The axillary nerve palsy had recovered partially by 8 months. One patient had an intraoperative graft fracture and postoperative shoulder stiffness, and the third patient had shoulder stiffness. Following the safety-driven nuanced steps in the Latarjet-Walch procedure, the short-term complication rate was 8%, and the neurological complication was 2% (n=3). The musculocutaneous and suprascapular nerves completely recovered, and the axillary nerve had partially recovered.

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

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. 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. 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 fromthe time of injury to reconstruction reduced the probability of achieving ≥M4 by 7% (CI, 1%-12%). 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. Therapeutic IV.

Origin and Distribution of the Brachial Plexus in Two Procyonids (Procyon cancrivorus and Nasua nasua, Carnivora).

Procyon cancrivorus and Nasua nasua are two procyonids with different evolutionary adaptations to use their thoracic limbs. Therefore, this study aimed to characterize the differences in the brachial plexus between both species. Five P. cancrivorus and five N. nasua cadavers were used to perform this investigation with the permission of the bioethics committee and environmental license. Gross dissections were performed on the cervical, pectoral, and thoracic limb regions to find the origin and distribution of the brachial plexus. The brachial plexus of both species originated in a variant manner from C5-T1, C5-T2, C6-T1, or C6-T2. All brachial plexus nerves were observed and, interestingly, the musculocutaneous sent a communicating branch to the median nerve medially to the axillary artery, forming an ansa axillaris in both species. An ansa pectoralis was also observed medially to the axillary artery. Additionally, in P. cancrivorus, the musculocutaneous nerve innervates the pronator teres and flexor carpi radialis muscles and communicates with the median nerve at the elbow level to continue as a common trunk at the antebrachium. The brachial plexus has differences between both procyonids, although in both species, it could conserve a primitive arrangement present within the infraorder Arctoidea.

Comparison of perineural brachial plexus block and proximal perivascular block in ultrasound-guided axillary brachial plexus block

The traditional axillary perineural (PN) approach for brachial plexus block is frequently used, but separate musculocutaneous nerve (MCN) block is required and increases procedure time and patient discomfort. We hypothesized that a block using the proximal perivascular (PPV) method at the MCN branching from the lateral cord would obviate the need for an MCN block while ensuring a quality similar to that of the PN method. For the PN group (n = 25), a needle was placed on each nerve, and 8 mL local anesthetic was infiltrated around the radial, ulnar, and median nerves (total: 24 mL). We then injected 6 mL local anesthetic around the MCN. In the PPV group (n = 25), we moved the probe proximally until the branching junction of the the MCN in the lateral cord. The needle tips were placed in the 12-o’clock and 6-o’clock positions of the axillary artery, and 15 mL local anesthetic was injected (total: 30 mL). The procedure time, number of needle passes, procedure-related complications, sensory/motor block level, and onset time were recorded. The PPV group had a significantly shorter procedure time than the PN group (3.9 ± 1.0 vs. 7.5 ± 3.3 min, p < 0.001). Furthermore, the PPV group required fewer needle passes. The PN group showed a significantly faster onset time than the PPV group (6.4 ± 2.7 vs. 10.4 ± 2.9 min, p < 0.001). The induction time did not show significant intergroup difference. Sensory blockade in the PN group occurred significantly faster than that in the PPV group at 5 and 10 min. There were no significant differences in motor nerve paralysis. PPV axillary block under ultrasound guidance was as effective as the PN axillary block. Therefore, the PPV axillary block is a simple, safe and effective regional technique for upper limb surgery.

Fentanyl sparing effect of ultrasound-guided proximal radial, ulnar, median, and musculocutaneous nerve (RUMM) block for radial and ulnar fracture repair in dogs: a retrospective case-control study.

This study retrospectively evaluated the fentanyl-sparing effect of ultrasound-guided proximal radial, ulnar, median, and musculocutaneous nerve (RUMM) block for radial and ulnar fracture repair in dogs. Fentanyl was prepared for intraoperative analgesia in dogs, although proximal RUMM block was performed using 0.5% or 0.25% bupivacaine before surgery in the block group. Dogs without a nerve block were assigned to the control group. The fentanyl dose in the block group [0.8 (0-1.9) μg/kg/hr] [median (interquartile range)] was significantly lower than in the control group [8.4 (7.2-10) μg/kg/hr]. Surgery was performed without fentanyl in >50% of the dogs (5/7), using 0.5% bupivacaine. Ultrasound-guided proximal RUMM block can be useful as an intraoperative analgesic for radial and ulnar fracture repair in dogs.

Prediction of Biceps Muscle Electromyogram Signal Using a NARX Neural Network.

This study was conducted to compare the response between the results of experimental data and the results achieved by the NARX neural network model to predict the electromyogram (EMG) signal on the biceps muscle in nonlinear stimulation conditions as a new stimulation model. This model is applied to design the controllers based on functional electrical stimulation (FES). To this end, the study was conducted in five stages, including skin preparation, placement of recording and stimulation electrodes, along with the position of the person to apply the stimulation signal and recording EMG, stimulation and recording of single-channel EMG signal, signal preprocessing, and training and validation of the NARX neural network. The electrical stimulation applied in this study is based on a chaotic equation derived from the Rossler equation and on the musculocutaneous nerve, and the response to this stimulation, i.e., the EMG signal, is from the biceps muscle as a single channel. The NARX neural network was trained, along with the stimulation signal and the response of each stimulation for 100 recorded signals from 10 individuals, and then validated and retested for trained data and new data after processing and synchronizing both signals. The results indicate that the Rossler equation can create nonlinear and unpredictable conditions for the muscle, and we also can predict the EMG signal with the NARX neural network as a predictive model. The proposed model appears to be a good method to predict control models based on FES and to diagnose some diseases.

Accessory heads of biceps brachii muscle its embryogenesis and clinical implications: Cadaveric study.

Biceps brachii is an elongated two-headed fusiform muscle of the anterior compartment of the arm which crosses the shoulder as well as the elbow joint. It assists in flexion of the shoulder joint and elbow joint and powerful supinator of the forearm. It also assists in the abduction of the shoulder joint. Accessory heads of biceps brachii muscle not only give additional strength to the joints, at the same time, they may also simulate soft-tissue tumors that can result in neurovascular compression. Accordingly, the aim of this study was designed to evaluate the prevalence of accessory heads of biceps brachii muscle in human cadavers. This study was conducted on 107 formalin embalmed human cadavers (male 62 and 45 female), and dissections were performed in accordance with the institutional ethical standards and the Indian Anatomy Act. Out of 107 cadavers, three-headed biceps brachii was noted in 18 cadavers (16.82%) associated with the unusual course of musculocutaneous nerve. Rare and unusual unilateral five-headed biceps brachii was noted in one male cadaver (0.93%). All accessory heads noted in this study were supplied by the separate branches of musculocutaneous nerve except the humeral head of five-headed biceps, which was supplied by the radial nerve. Awareness of these anatomical variations, knowledge is necessary for radiologists, anesthetists, physiotherapists, and orthopedic surgeons to avoid complications during various radiodiagnostic procedures or surgeries of flexor deformities of the upper arm and forearm.

Low rates of serious complications after open Latarjet procedure at short-term follow-up

To report on intraoperative and short-term postoperative adverse events after open Latarjet procedure in patients with recurrent anterior shoulder instability. These complications were classified into different grades of severity based on the treatment required and the learning curve of the procedure. Ninety-six patients (102 shoulders) underwent open Latarjet procedure for recurrent post-traumatic anterior glenohumeral instability between 2012 and 2020. The minimum duration of patients' follow-up was 6 months. Adverse events were classified into 3 classes based on the severity and subsequent treatment. The complications in the first 50% of all cases were compared with the latter 50% to evaluate the role of learning curve on the complication rates. The mean follow-up was 7.2±2.8 months. The patients' mean age was 26.7±8.9 years and consisted of 83 (86.4%) male and 13 (13.6%) female patients. The total adverse events rate was 18.6%. Adverse events requiring no additional treatment (class 1) occurred in 6 cases (5.8%) including fibrous union (3.9%) and asymptomatic resorption of the graft (1.9%). Adverse events requiring additional or extended nonoperative management (class 2) occurred in 8 cases (7.8%), including coracoid fracture (2.9%), musculocutaneous nerve palsy (1.9%), axillary nerve palsy (0.9%), suprascapular nerve palsy (0.9%), and stiffness (0.9%). All the nerve palsies recovered without long-term sequelae. Adverse events requiring secondary operative procedures (class 3) occurred in 5 cases (4.9%), including symptomatic hardware (1.9%), medial healing of the graft (0.9%), screw loosening (0.9%), and deep infection (0.9%). The rate of adverse events in revision cases was higher than primary cases in 11.7% and 6.8%, respectively (P=.119). The complication rate was significantly higher in the first half of the surgeons' practice (14.7%) than in the second half (3.9%) (P ≤ .05). The overall complication rate reported in this open Latarjet series is 18.6%; however, the rate of class 3 adverse events that required additional surgery or long-term medical treatment was only 4.9%. Revision cases had a higher rate of complications than primary cases, and the learning curve has had a significant impact on the rate of adverse events.

Oberlin transfer for C5-6 palsy after posterior cervical spine surgery.

Postoperative C5-6 palsies can occur in 5%-10% of cases after cervical spine surgery. In this video, the authors demonstrate operative techniques for nerve transfer to restore function for postoperative C5-6 palsy. The patient underwent C3-6 laminectomy and posterior fusion for cervical spondylotic myelopathy and developed weakness postoperatively in the C5-6 distribution bilaterally. He experienced spontaneous recovery to near full strength in the most affected muscle groups by 12 months except the left biceps (2/5), with at least antigravity shoulder abduction. He underwent left ulnar to musculocutaneous nerve fascicular transfer to improve elbow flexion and supination in the setting of good hand function. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID22100.

Ulnar fascicle to brachialis branch of musculocutaneous nerve for restoration of elbow flexion associated with spinal cord tumor and radiation-induced lower motor neuron disease

Transfer of the ulnar fascicle to the biceps branch of the musculocutaneous nerve, or Oberlin transfer, has been widely used for the treatment of elbow flexion weakness in the setting of upper trunk brachial plexus palsy. The authors present a modified application of this technique for restoration of functional elbow flexion in a 30-year-old woman with a history of recurrent upper cervical spinal cord pilocytic astrocytoma, complex spinal deformity, and radiation-induced lower motor neuron disease. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID2299.

Chronic Musculocutaneous Nerve Injury: An Important Differential in Progressive Arm Atrophy

An isolated musculocutaneous nerve (MCN) injury is a rare condition that can be easily missed if it presents late. A 28-year-old man reported painless and progressive wasting of the right arm for 6 months. On examination, there was visible wasting of the right biceps brachii muscle along with its slight weakness, depressed biceps jerk, and an impaired pinprick sensation in the lateral antebrachial cutaneous nerve distribution. He described a history of a road traffic accident 14 months beforehand. Based on the history and clinical examination, the differential diagnosis included an isolated MCN injury, upper trunk plexopathy, lateral cord plexopathy, C5/6 radiculopathy, and monomelic amyotrophy involving the C5/6 myotomes on the right side. The results of nerve conduction studies and electromyography were consistent with chronic proximal MCN neuropathy (right). In cases of arm wasting without pain or numbness, MCN injury should be included in the differential diagnosis, even in the presence of good power of the elbow flexors. The importance of detailed history-taking and clinical correlation cannot be over-emphasized in such cases.

Study of Two Different Volumes of 0.75% Ropivacaine for Ultrasound Guided Supraclavicular Brachial Plexus Block on Successful Blockade and Diaphragmatic Motility

Background 
 Use of ultrasound guidance during supraclavicular brachial plexus block allows the usage of a lower anesthetics dose and minimizing unwanted effects of the anesthesia.
 Objective To compare the success of sensory blockade and the incidence of hemidiaphragmatic dysfunction in patients receiving two different volume of 0.75% Ropivacaine for ultrasound guided supraclavicular brachial plexus block.
 Method A prospective randomized double-blinded comparative study was conducted. Group A patients (n=30) received 20 ml and Group B (n=30) received 25 ml of 0.75% Ropivacaine for ultrasound guided supraclavicular brachial plexus block. Hemodynamic parameters, oxygen saturation, diaphragmatic excursion, onset of sensory blockade and time for completion of blockade were measured. Independent t-test, Chi-square test and Mann-Whitney U test were used to analyze the data at p value of less than 0.05 using Statistical Package for Social sciences (version 11.5).
 Result At 30 minutes, 29 (96.67%) patients in group B and 27 (90.0%) patients in group A had no sensation in median, radial, ulnar, musculocutaneous and medial cutaneous nerves territories; however, it was not significant statistically (p value > 0.05). At 30 minutes in Group A, 25 (83.33%) patients had no diaphragmatic hemiparesis and five (16.67%) patients had partial diaphragmatic hemiparesis. However, three (10%) patients had no diaphragmatic hemiparesis in Group B, 25 (83.33%) patients had partial and two (6.67%) patients had complete diaphragmatic hemiparesis and it was statistically significant (p < 0.05). Age and sex had no effect on diaphragmatic hemiparesis in both groups (p value > 0.05).
 Conclusion The patients receiving lower volume of Ropivacaine had less incidence of hemidiaphragmatic dysfunction with similar sensory blockade as compared to the patients receiving higher volume of Ropivacaine.

Nonlinear analysis of biceps surface EMG signals for chaotic approaches

In the present study, the chaos is detected and quantified in the electromyographic (EMG) signal of the biceps muscle using nonlinear features. Biological systems are complex and nonlinear systems composed of a large number of interconnected elements. A thorough understanding of the behavior of these systems, which are sometimes chaotic, will lead to an understanding of the behavior of diseases, finding effective treatments, and using appropriate rehabilitation equipment. Therefore, designing a novel stimulation equation based on Rossler nonlinear dynamics causes chaos in the biceps EMG signal. This stimulation, the sitting and hand positioning is designed in such a way to prevent muscle fatigue and saturated stimulability and also to ensure that with minimal stimulation of the musculocutaneous nerve, there is a maximum activity in the biceps muscle. Then, each signal was divided into chaotic and non-chaotic parts with the positive largest Lyapunov exponent (LLE), and its nonlinear and chaotic criteria, including fractal dimension (FD) using Petrosian method, correlation dimension (CD), for both parts of the EMG signal were calculated as first time. Then, after applying the values of these criteria as features to the support vector machine (SVM) classifier, the separation was carried out using a linear kernel. The results showed that if the classification features include the two features of FD and CD, they are separated from non-chaotic EMG signals with 98.97 % accuracy. Finally, for the first time the extracted features of CD, FD are a good representation of the chaotic behavior of the biceps EMG signal.

A rare variant branch from the lateral cord and a communicating branch between the musculocutaneous and median nerve

During routine educational gross anatomy dissections of the upper extremities, one right upper limb was observed to have an unusual branch from the lateral cord that pierced coracobrachialis towards its origin. This variant branch emerged from the lateral cord before it branched to give its contribution to the median nerve and musculocutaneous nerve in the axilla. The same limb also had a communicating branch between the musculocutaneous nerve to the median nerve at the mid arm level. These variations may be of interest to neurologists, anatomists and surgeons operating in the upper limb region.

An unusual median nerve formation; A case report and literature review

The Median nerve anatomical variation is commonly encountered. During the dissection of about 65 years of formalin-fixed male cadaver at the Department of Human Anatomy at National University Faculty of Medicine for undergraduate students in 2016-2017, the left upper limb showed that the median nerve was formed by the union of the three roots. However, the third root arose from the musculocutaneous nerve inside the coracobrachialis muscle, perforating the lower part of the muscle and joining the median nerve at the middle of the arm region. Knowledge of these variations is useful clinically, especially when evaluating symptoms of upper limb trauma, and it is also useful when performing surgical approaches.

Топографическая анатомия плечевого сплетения и возможности эндоскопического доступа (кадаверное исследование)

Relevance The brachial plexus is a complex anatomical structure the passes through three narrow anatomical spaces including the interscalene space, the space between the first rib and the clavicle (thoracic aperture), the space between the anterior chest wall and the pectoralis minor muscle. Compression of the brachial plexus and the vascular band can occur at the sites. Endoscopic approach to the brachial plexus is a promising surgical trend to allow neurolysis and decompression of the plexus with minimal trauma and blood loss and a good cosmetic result. The purpose was to explore topographic anatomy of the brachial plexus and surrounding structures and determine the possibility of endoscopic approach to the brachial plexus. Material and methods The shoulder and neck were dissected in 5 fresh cadavers. The study was performed at Trauma and Orthopaedics department of the Russian Peoples Friendship University and Department of pathological anatomy at the Buyanov’s Moscow State City Hospital between 2021 and 2022. Results The pectoralis minor muscle was detached from the coracoid process to endoscopically approach to the subclavian part of plexus. The lateral aspect of the subclavian muscle was detached from the clavicle to endoscopically approach to the thoracic aperture. Portals were produced at the supraclavicular fossa to endoscopically approach to the supraclavicular part of the plexus in the interscalene space considering the topographic anatomy of the jugularis external vein and accessory veins. The mean distance from the coracoid tip to the penetration point of the musculo-cutaneous nerve to the conjoint tendon was 3 cm. The mean distance between the anterior chest wall and the clavicle (width of thoracic aperture) was 1.86 cm. The mean distance between the sternal end of the clavicle to the point of passage of the subclavian artery under the clavicle was 5.7 cm. The mean width of the interscalene space was 1.4 cm. Discussion Aspects of topographic anatomy of the brachial plexus were examined in cadaveric studies of Sidorovich R.R. (2011), Chembrovich V.V. (2019), Anokhina Z.A. (2021), but endoscopic approach to the brachial plexus and possibility with endoscopic surgery were not discussed in the studies. Foreign cadaveric studies of Akaslan I. (2021), Koyyalamudi V. (2021), Costabeber I. (2010), Akboru (2010) were performed to examine topographic anatomy of the brachial plexus. The only study reporting the possibility of endoscopic approach to the brachial plexus and endoscopic anatomy was performed by Lafosse T. (2015). Our cadaveric series reported the possibility of endoscopic approach to the brachial plexus at the three levels for the first time in Russian literature. Conclusion Topographic anatomy of the supraclavicular and infraclavicular portions of the brachial plexus was examined in our series. The study showed the possibility of endoscopic approach to the brachial plexus at the interscalene space, thoracic aperture and subclavian area.

Supercharge End-to-Side Sensory Transfer to A Long Nerve Graft to Enhance Motor Regeneration in A Brachial Plexus Model-An Experimental Rat Study.

Long nerve grafts will affect muscle recovery. Aim of this study is to investigate if supercharged end-to-side (SETS) sensory nerve transfer to long nerve graft can enhance functional outcomes in brachial plexus animal model. A reversed long nerve graft (20-23-mm) was interposed between C6 and musculocutaneous nerve (MCN) in 48 SD rats. The sensory nerves adjacent to the proximal and distal coaptation sites of the nerve graft were used for SETS. There were four groups with 12 rats in each: (A) nerve graft alone, (B) proximal SETS sensory transfer, (C) distal SETS sensory transfer, and (D) combined proximal and distal SETS sensory transfers. Grooming test at 4, 8, 12 and 16 weeks, and compound muscle action potentials (CMAP), biceps tetanic muscle contraction force, muscle weight and MCN axon histomorphologic analysis at 16 weeks were assessed. Grooming test was significantly better in group C and D at 8 weeks (p = 0.02 and p = 0.04) and still superior at 16 weeks. There was no significant difference in CMAP, tetanic muscle contraction force, or muscle weight. The axon counts showed all experimental arms were significantly higher than the unoperated arms. Although the axon count was lowest in group C and highest in group D (p = 0.02), the nerve morphology tended to be better in group C overall. Distal sensory SETS transfer to a long nerve graft showed benefits of functional muscle recovery and better target nerve morphology. Proximal sensory inputs do not benefit the outcomes at all.