Restoration of active pick-up function in patients with total brachial plexus avulsion injuries

A rat model of modified contralateral C7 transfer permitting ulnar nerve recovery

BACKGROUND

Contralateral C7 transfer (cC7) is an important treatment for total brachial plexus avulsion (TBPA), which sacrifices the recovery of the ulnar nerve (UN). The present study aimed to introduce an animal model of modified cC7 that preserved the deep branch of ulnar nerve (dbUN) and verify its feasibility.

METHODS

Anatomical study: Lengths, diameters, and axon counts of dbUN and anterior interosseous (AIN) branches in six rats were measured. In vivo surgery: 18 rats were divided into three groups. Group A: Traditional cC7. Group B: Modified cC7 finished in one stage. Group C: Modified cC7 and AIN branch anastomosed with dbUN one month after the first stage. Electrophysiological examinations, muscle wet weight, muscle cross-sectional areas, and nerve axon counts were evaluated six months postoperatively.

RESULTS

Anatomical study: The distances from dbUN and AIN branches to the midpoint of the inner and outer epicondyles connection of the humerus, diameters, and axon numbers of dbUN and AIN branches were analyzed, then AIN terminal branch (tbAIN) was anastomosed with dbUN. In vivo surgery: The differences in median nerve fiber counts were not significant. There were more UN axons in group A than in groups B and C. In electrophysiological examinations, muscle wet weight and cross-sectional area of the flexor digitorum profundus showed no significant difference, but the second interosseus cross-sectional areas in groups B and C were significantly larger than in group A.

CONCLUSIONS

This study established an animal model of preserving dbUN in cC7 and verified its feasibility. The possibility of restoring dbUN was established.

Restoration of Grasp after Single-Stage Free Functioning Gracilis Muscle Transfer in Traumatic Adult Pan-Brachial Plexus Injury

BACKGROUND

A variety of approaches have been described to obtain rudimentary grasp after traumatic pan-brachial plexus injury in adults. The aim of this study is to evaluate hand prehension after a gracilis single-stage free functioning muscle transfer.

METHODS

Twenty-seven patients who underwent gracilis single-stage free functioning muscle transfer for elbow flexion and hand prehension after a pan-plexus injury were included. All patients presented with a minimum of 2 years of follow-up. Postoperative finger flexion, elbow flexion strength, preoperative and postoperative Disability of the Arm, Shoulder, and Hand questionnaire scores, secondary hand procedures, complications, and demographic characteristics were analyzed.

RESULTS

Twenty patients (74%) demonstrated active finger pull-through. Only six patients (25%) considered their hand function useful for daily activities. Disability of the Arm, Shoulder, and Hand score improved by 13.1 ± 13.7 ( P < 0.005). All patients were expected to require one secondary procedure (wrist fusion, thumb carpometacarpal fusion, and/or thumb interphalangeal fusion) because no extensor reconstruction was performed. These were performed in 89%, 78%, and 74% of patients, respectively. Four postoperative complications (hematoma, seroma, wound dehiscence, and skin paddle loss) occurred. No flap loss occurred.

CONCLUSIONS

In pan-plexus injuries, the use of a gracilis single-stage free functioning muscle transfer is an alternative to the double free functioning muscle transfer procedure and contralateral C7 transfer, especially for patients who are unable to undergo two to three important operations in a short period of time. Further research and studies are required to improve hand function in these patients.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, IV.

Reconstruction of hook grip function of the fingers in patients with traumatic brachial plexus injury

We described a reconstruction method for restoring hook grip function of the fingers in patients with total brachial plexus injury. The paralysed latissimus dorsi muscle was transferred to the upper limb as a pedicle flap and sutured to the flexor digitorum profundus tendons. The muscle was then reanimated with two intercostal donor nerves to the thoraco-dorsal nerve. Fourteen young adult patients (mean 23 years, range 17 to 32 years) with traumatic brachial plexus injury who underwent reconstruction using this technique from 2000 to 2019. After mean follow-up of 65 months (range 20 to 170), finger flexion of strength greater than or equal to M3 was achieved in 10 of the 14 patients. The mean weight that could be lifted using a hook grip was 2.6 kg, and that which could be lifted with both hands was 4.1 kg. The intercostal nerve-innervated latissimus dorsi muscle transfer can provide useful hook grip hand function without the need to sacrifice donor vessels or healthy muscles.Level of evidence: IV.

Functional outcome of contralateral C7 nerve transfer combined with free functional gracilis transplantation to repair total brachial plexus avulsion: a report of thirty-nine cases

Purpose

Treatment of total brachial plexus avulsion (TBPA) is a challenge in the clinic, especially the restoration of hand function. The current main surgical order is from proximal to distal joints. The purpose of this study was to demonstrate the outcomes of “distal to proximal” surgical method.

Methods

Thirty-nine patients underwent contralateral C7 (CC7) nerve transfer to directly repair the lower trunk (CC7-LT) and phrenic nerve transfer to the suprascapular nerve (PN-SSN) during the first stage, followed by free functional gracilis transplantation (FFGT) for elbow flexion and finger extension. Muscle strength of upper limb, degree of shoulder abduction and elbow flexion, and Semmes–Weinstein monofilament test and static two-point discrimination of the hand were examined according to the modified British Medical Research Council (mBMRC) scoring system.

Results

The results showed that motor recovery reached a level of M3 + or greater in 66.7% of patients for shoulder abduction, 87.2% of patients for elbow flexion, 48.7% of patients for finger extension, and 25.6% of patients for finger flexion. The mean shoulder abduction angle was 45.5° (range 0–90°), and the average elbow flexion angle was 107.2° (range 0–142°), with 2.5 kg average flexion strength (range 0.5–5 kg). In addition, protective sensibility (≥ S2) was found to be achieved in 71.8% of patients.

Conclusion

In reconstruction of TBPA, CC7 transfer combined with free functional gracilis transplantation is an available treatment method. It could help patients regain shoulder joint stability and the function of elbow flexion and finger extension and, more importantly, provide finger sensation and partial finger flexion function. However, the pick-up function was unsatisfied, which needed additional surgery.

Differences in management and treatment of traumatic adult pan brachial plexus injuries: a global perspective regarding continental variations

An expert opinion study was designed to query five countries and six brachial plexus surgeons regarding the demographics, mechanisms of injury, evaluation, timing of surgery, reconstructive strategies and controversies in adult traumatic pan brachial plexus injuries. Variations in assessing outcomes, management of neuropathic pain and future considerations were elucidated. Clear differences in regional demographics, mechanisms of injury, patient evaluation and treatment strategies were identified. The role of phrenic nerve and contralateral C7 transfer, acute use of free functioning muscle transfers, root reimplantation and amputation/myoelectric prosthetic fitting were regional/surgeon dependent. Comparison of outcomes across regions requires an understanding of the regional nuances of patient demographics, injury mechanisms, preferred reconstructive strategies and how outcomes are measured. Future studies are required to allow accurate regional comparisons.

Direct Repair of the Lower Trunk to Residual Nerve Roots for Restoration of Finger Flexion After Total Brachial Plexus Injury

PURPOSE

Residual nerve root stumps have been used to neurotize the median nerve in an attempt to restore finger flexion function in patients suffering from total brachial plexus injury. However, the results have been unsatisfactory mainly because of the need to use a long nerve graft. The authors have tried to improve the quality of restored finger flexion by direct approximation of available (ruptured) ipsilateral root stumps to the lower trunk (LT). We sought to validate these results using objective outcome measures.

METHODS

This is a study of 27 cases of total posttraumatic brachial plexus palsies. In each case, the neck was explored and ruptured root stumps identified. The LT was mobilized by separating it from the posterior division and the medial cutaneous nerve of the forearm distally. The mobilized LT was then approximated directly to an ipsilateral root stump. The arm was immobilized against the trunk for 2 months. The patients were observed for return of function in the paralyzed upper limb. The presence and strength of finger flexion was measured using the British Medical Council grading.

RESULTS

The follow-up period was 36 to 74 months (average, 56.9 ± 13.7 months). Recovery of active finger flexion was M4 in 10 patients, M3 in 8 patients, and M2 to M0 in 9 patients. Meaningful recovery (M3 or greater) of finger flexion was achieved in 18 of 27 patients.

CONCLUSIONS

The results of active finger flexion can be improved by direct approximation of the LT to an ipsilateral root stump.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Analysis of human acellular nerve allograft combined with contralateral C7 nerve root transfer for restoration of shoulder abduction and elbow flexion in brachial plexus injury: a mean 4-year follow-up

OBJECTIVE

Human acellular nerve allograft applications have increased in clinical practice, but no studies have quantified their influence on reconstruction outcomes for high-level, greater, and mixed nerves, especially the brachial plexus. The authors investigated the functional outcomes of human acellular nerve allograft reconstruction for nerve gaps in patients with brachial plexus injury (BPI) undergoing contralateral C7 (CC7) nerve root transfer to innervate the upper trunk, and they determined the independent predictors of recovery in shoulder abduction and elbow flexion.

METHODS

Forty-five patients with partial or total BPI were eligible for this retrospective study after CC7 nerve root transfer to the upper trunk using human acellular nerve allografts. Deltoid and biceps muscle strength, degree of shoulder abduction and elbow flexion, Semmes-Weinstein monofilament test, and static two-point discrimination (S2PD) were examined according to the modified British Medical Research Council (mBMRC) scoring system, and disabilities of the arm, shoulder, and hand (DASH) were scored to establish the function of the affected upper limb. Meaningful recovery was defined as grades of M3-M5 or S3-S4 based on the scoring system. Subgroup analysis and univariate and multivariate logistic regression analyses were conducted to identify predictors of human acellular nerve allograft reconstruction.

RESULTS

The mean follow-up duration and the mean human acellular nerve allograft length were 48.1 ± 10.1 months and 30.9 ± 5.9 mm, respectively. Deltoid and biceps muscle strength was grade M4 or M3 in 71.1% and 60.0% of patients. Patients in the following groups achieved a higher rate of meaningful recovery in deltoid and biceps strength, as well as lower DASH scores (p < 0.01): age < 20 years and age 20-29 years; allograft lengths ≤ 30 mm; and patients in whom the interval between injury and surgery was < 90 days. The meaningful sensory recovery rate was approximately 70% in the Semmes-Weinstein monofilament test and S2PD. According to univariate and multivariate logistic regression analyses, age, interval between injury and surgery, and allograft length significantly influenced functional outcomes.

CONCLUSIONS

Human acellular nerve allografts offered safe reconstruction for 20- to 50-mm nerve gaps in procedures for CC7 nerve root transfer to repair the upper trunk after BPI. The group in which allograft lengths were ≤ 30 mm achieved better functional outcome than others, and the recommended length of allograft in this procedure was less than 30 mm. Age, interval between injury and surgery, and allograft length were independent predictors of functional outcomes after human acellular nerve allograft reconstruction.

Comparison between direct repair and human acellular nerve allografting during contralateral C7 transfer to the upper trunk for restoration of shoulder abduction and elbow flexion

Direct coaptation of contralateral C7 to the upper trunk could avoid the interposition of nerve grafts. We have successfully shortened the gap and graft lengths, and even achieved direct coaptation. However, direct repair can only be performed in some selected cases, and partial procedures still require autografts, which are the gold standard for repairing neurologic defects. As symptoms often occur after autografting, human acellular nerve allografts have been used to avoid concomitant symptoms. This study investigated the quality of shoulder abduction and elbow flexion following direct repair and acellular allografting to evaluate issues requiring attention for brachial plexus injury repair. Fifty-one brachial plexus injury patients in the surgical database were eligible for this retrospective study. Patients were divided into two groups according to different surgical methods. Direct repair was performed in 27 patients, while acellular nerve allografts were used to bridge the gap between the contralateral C7 nerve root and upper trunk in 24 patients. The length of the harvested contralateral C7 nerve root was measured intraoperatively. Deltoid and biceps muscle strength, and degrees of shoulder abduction and elbow flexion were examined according to the British Medical Research Council scoring system; meaningful recovery was defined as M3–M5. Lengths of anterior and posterior divisions of the contralateral C7 in the direct repair group were 7.64 ± 0.69 mm and 7.55 ± 0.69 mm, respectively, and in the acellular nerve allografts group were 6.46 ± 0.58 mm and 6.43 ± 0.59 mm, respectively. After a minimum of 4-year follow-up, meaningful recoveries of deltoid and biceps muscles in the direct repair group were 88.89% and 85.19%, respectively, while they were 70.83% and 66.67% in the acellular nerve allografts group. Time to C5/C6 reinnervation was shorter in the direct repair group compared with the acellular nerve allografts group. Direct repair facilitated the restoration of shoulder abduction and elbow flexion. Thus, if direct coaptation is not possible, use of acellular nerve allografts is a suitable option. This study was approved by the Medical Ethical Committee of the First Affiliated Hospital of Sun Yat-sen University, China (Application ID: [2017] 290) on November 14, 2017.

Repair of long segmental ulnar nerve defects in rats by several different kinds of nerve transposition

Multiple regeneration of axonal buds has been shown to exist during the repair of peripheral nerve injury, which confirms a certain repair potential of the injured peripheral nerve. Therefore, a systematic nerve transposition repair technique has been proposed to treat severe peripheral nerve injury. During nerve transposition repair, the regenerated nerve fibers of motor neurons in the anterior horn of the spinal cord can effectively grow into the repaired distal nerve and target muscle tissues, which is conducive to the recovery of motor function. The aim of this study was to explore regeneration and nerve functional recovery after repairing a long-segment peripheral nerve defect by transposition of different donor nerves. A long-segment (2 mm) ulnar nerve defect in Sprague-Dawley rats was repaired by transposition of the musculocutaneous nerve, medial pectoral nerve, muscular branches of the radial nerve and anterior interosseous nerve (pronator quadratus muscle branch). In situ repair of the ulnar nerve was considered as a control. Three months later, wrist flexion function, nerve regeneration and innervation muscle recovery in rats were assessed using neuroelectrophysiological testing, osmic acid staining and hematoxylin-eosin staining, respectively. Our findings indicate that repair of a long-segment ulnar nerve defect with different donor nerve transpositions can reinnervate axonal function of motor neurons in the anterior horn of spinal cord and restore the function of affected limbs to a certain extent.

Repair of peripheral nerve defects by nerve transposition using small gap bio-sleeve suture with different inner diameters at both ends

During peripheral nerve transposition repair, if the diameter difference between transposed nerves is large or multiple distal nerves must be repaired at the same time, traditional epineurial neurorrhaphy has the problem of high tension at the suture site, which may even lead to the failure of nerve suture. We investigated whether a small gap bio-sleeve suture with different inner diameters at both ends can be used to repair a 2-mm tibial nerve defect by proximal transposition of the common peroneal nerve in rats and compared the results with the repair seen after epineurial neurorrhaphy. Three months after surgery, neurological function, nerve regeneration, and recovery of nerve innervation muscle were assessed using the tibial nerve function index, neuroelectrophysiological testing, muscle biomechanics and wet weight measurement, osmic acid staining, and hematoxylin-eosin staining. There was no obvious inflammatory reaction and neuroma formation in the tibial nerve after repair by the small gap bio-sleeve suture with different inner diameters at both ends. The conduction velocity, muscle strength, wet muscle weight, cross-sectional area of muscle fibers, and the number of new myelinated nerve fibers in the bio-sleeve suture group were similar to those in the epineurial neurorrhaphy group. Our findings indicate that small gap bio-sleeve suture with different inner diameters at both ends can achieve surgical suture between nerves of different diameters and promote regeneration and functional recovery of injured peripheral nerves.

[Construction of Chinese peripheral nerve society and progress in repair and reconstruction of peripheral nerve injury]

The peripheral nerve group of the reparative and reconstructive surgery committee (branch of Chinese association of rehabilitation medicine) was established in 1995. Major research progress has been made in the repair, regeneration, and reconstruction of peripheral nerve injury. Professor GU Yudong initiated the contralateral cervical7 root (CC7) transfer for the treatment of total brachial plexus root injury in 1986. Now this method has been applied safely and effectively for 30 years with profound progress and refinement. In addition, the repair and reconstruction of peripheral nerve injury had achieved great development such as the treatment of spastic paralysis of upper limb, CC7 transfer using a modified prespinal route, the reconstruction of bladder function after spinal cord injury, the development of acellular allograft nerve, the small gap suture technique, the functioning free gracilis muscle transplantation, and contralateral S ₁ transfer which have been widely used in clinical application with good outcomes. With the progress of the biological manufacturing of peripheral nerve bio-materials and the remodeling of central nervous system after brachial plexus injury, a novel peripheral neuroscience research field was growing up. It is still a challenge for surgeons and scholars in this field to insist on the popularization and improvement of peripheral nerve repair and reconstruction by microsurgical technique, and to make efforts to transform the results of peripheral nerve research into clinical practice.