Salvage of cervical motor radiculopathy using peripheral nerve transfer reconstruction

Ten Myths in Nerve Surgery

Background

Surgical innovation has provided new options for the management of complex peripheral nerve injuries, generating renewed interest in this field. Historic literature may be misinterpreted or misquoted, or create dogma, which is perpetuated in teaching, research publications, and clinical practice. The management of peripheral nerve injuries is based on complex decision-making, with potential lifelong ramifications for patients incorrectly receiving an expectant or surgical management plan.

Methods

This article includes opinion from expert leaders in the field of peripheral nerve surgery and questions some of the current assumptions and preconceptions around nerve surgery based on clinical evidence. There was extensive debate regarding the contents of the final article, and the different opinions expressed represent the uncertainty in this field and the differing levels of confidence in available published evidence.

Results

Individual practices vary and, therefore, absolute consensus is impossible to achieve. The work is presented as 10 myths which are assessed using both historical and emerging evidence, and areas of uncertainty are discussed.

Conclusions

It is important to learn lessons from the past, and scholars of history bear the task of ensuring references are accurately quoted. Expunging myths will enhance care for patients, focus research efforts, and expand on the surgical possibilities within this specialty.

Versatility of the double fascicular transfer in reconstruction of elbow flexion paralysis: Intermediate term follow-up and patient-related outcome measures

OBJECTIVES

The use of fascicle transfers in the reconstruction of traumatic brachial plexus injury is well established, but limited evidence is available regarding their use in atraumatic elbow flexion paralysis. This retrospective case review aimed to verify whether median and ulnar fascicle transfers are similarly effective in atraumatic versus traumatic elbow flexion paralysis when measured using the British Medical Research Council (MRC) scale, Brachial plexus Assessment Tool (BrAT) and Stanmore Percentage of Normal Elbow Assessment (SPONEA) scores at long-term follow-up.

METHODS

All median and ulnar fascicle transfer cases performed at the Queen Elizabeth Hospital Birmingham between August 2007 and November 2018 were reviewed to compare the outcomes of transfers performed for traumatic and atraumatic indications. Data on patient demographics, mechanism and nature of injury, date of injury or symptom onset, date of operation, and other nerve transfers performed were collected. Outcome measures collected included the British MRC scale and two patient-reported outcome measures (PROMs), BrAT and SPONEA.

RESULTS

In total, 34 patients with 45 median and ulnar fascicle transfers were identified. This included 27 traumatic and seven atraumatic brachial plexus insults. Thirty patients had sufficient follow-up to be included in MRC analysis and 17 patients had sufficient follow-up to be included in PROM analysis. No significant differences were found between traumatic and atraumatic subgroups for median MRC, BrAT, or SPONEA scores.

CONCLUSIONS

This study suggests that nerve transfers might be considered effective reconstructive options in atraumatic pathology and provides validation for further research on the subject.

L4-to-L4 nerve root transfer for hindlimb hemiplegia after hypertensive intracerebral hemorrhage

There is no effective treatment for hemiplegia after hypertensive intracerebral hemorrhage. Considering that the branches of L4 nerve roots in the lumbar plexus root control the movement of the lower extremity anterior and posterior muscles, we investigated a potential method of nerve repair using the L4 nerve roots. Rat models of hindlimb hemiplegia after a hypertensive intracerebral hemorrhage were established by injecting autogenous blood into the posterior limb of internal capsule. The L4 nerve root on the healthy side of model rats was transferred and then anastomosed with the L4 nerve root on the affected side to drive the extensor and flexor muscles of the hindlimbs. We investigated whether this method can restore the flexible movement of the hindlimbs of paralyzed rats after hypertensive intracerebral hemorrhage. In a beam-walking test and ladder rung walking task, model rats exhibited an initial high number of slips, but improved in accuracy on the paretic side over time. At 17 weeks after surgery, rats gained approximately 58.2% accuracy from baseline performance and performed ankle motions on the paretic side. At 9 weeks after surgery, a retrograde tracing test showed a large number of fluoro-gold-labeled motoneurons in the left anterior horn of the spinal cord that supports the L4-to-L4 nerve roots. In addition, histological and ultramicrostructural findings showed axon regeneration of motoneurons in the anterior horn of the spinal cord. Electromyography and paw print analysis showed that denervated hindlimb muscles regained reliable innervation and walking coordination improved. These findings suggest that the L4-to-L4 nerve root transfer method for the treatment of hindlimb hemiplegia after hypertensive intracerebral hemorrhage can improve the locomotion of hindlimb major joints, particularly of the distal ankle. Findings from study support that the L4-to-L4 nerve root transfer method can effectively repair the hindlimb hemiplegia after hypertensive intracerebral hemorrhage. All animal experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Nanjing Medical University (No. IACUC-1906009) in June 2019.

Timing of referral to peripheral nerve specialists in patients with postoperative C5 palsy

The objective of this study was to examine the association between electrophysiology data post-C5-palsy and referral to peripheral nerve surgeons (PNS) using a 15-year cohort of patients who underwent posterior cervical decompression. Endpoints included the associations of postoperative treatments employed with functional recovery and abnormal electrophysiology data. Of 77 included patients (median 64 yr; 68% male), 48% completely recovered. The most common treatments were physical therapy (90%), occupational therapy (34%), oral corticosteroids (18%), and PNS referral (17%). Baseline weakness did not associate with PNS referral or postoperative treatment strategy. None of the treatments predicted recovery, though patients with no [versus complete] recovery were more likely to be recommended for nerve transfers (22.2 vs 0%; p = 0.03). Abnormal electromyography data associated with PNS referral (p < 0.01), nerve transfer recommendation (p < 0.01), occupational therapy referral, and oral corticosteroid therapy. Abnormal findings on EMG obtained between 6-weeks and 6-months post-injury were the most strongly associated with peripheral nerve surgeon referral (p = 0.02) and nerve transfer recommendation (p < 0.01). These data suggest strategies for postoperative C5 palsy management are highly heterogeneous. None of the treatments employed significantly predicted the extent of functional recovery. However, patients with abnormal electrophysiology results were most likely to receive multimodal treatment, suggesting these results may significantly alter medical management of patients with postoperative C5 palsy. Early (6-week to 6-month) electrophysiology data may help to ensure that patients likely to benefit from nerve transfer procedures are referred to a PNS within the 9-12-month time frame associated with the best recovery of function.

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.