Reverse End-to-Side Nerve Transfer for Severe Ulnar Nerve Injury: A Western Canadian Multicentre Prospective Nonrandomized Cohort Study

BACKGROUND

Reverse end-to-side (RETS) nerve transfer has become increasingly popular in patients with severe high ulnar nerve injury, but the reported outcomes have been inconsistent.

OBJECTIVE

To evaluate the "babysitting effect," we compared outcomes after anterior interosseous nerve RETS transfer with nerve decompression alone. To evaluate the source of regenerating axons, a group with end-to-end (ETE) transfer was used for comparisons.

METHODS

Electrophysiology measures were used to quantify the regeneration of anterior interosseous nerve (AIN) and ulnar nerve fibers while functional recovery was evaluated using key pinch and Semmes-Weinstein monofilaments. The subjects were followed postsurgically for 3 years.

RESULTS

Sixty-two subjects (RETS = 25, ETE = 16, and decompression = 21) from 4 centers in Western Canada were enrolled. All subjects with severe ulnar nerve injury had nerve compression at the elbow except 10 in the ETE group had nerve laceration or traction injury. Postsurgically, no reinnervation from the AIN to the abductor digiti minimi muscles was seen in any of the RETS subjects. Although there was no significant improvement in compound muscle action potentials amplitudes and pressure detection thresholds in the decompression and RETS group, key pinch strength significantly improved in the RETS group ( P < .05).

CONCLUSION

The results from published clinical trials are conflicting in part because crossover regeneration from the donor nerve has never been measured. Unlike those with ETE nerve transfers, we found that there was no crossover regeneration in the RETS group. The extent of reinnervation was also no different from decompression surgery alone. Based on these findings, the justifications for this surgical technique need to be carefully re-evaluated.

Comparison of conduit and autograft efficiency in repairing femoral nerve injury in New Zealand rabbits

Background: Peripheral nerve injuries may affect all age groups and exert devastating impacts on the professional and personal life of the patients. The investigation of nerve regeneration and use of biomaterials and synthetic materials have resulted in advancements in the treatment of peripheral nerve injuries and lesions. Nerve conduits can be used to adjoin the digital sensory nerve spaces of less than 3 cm, especially when the direct tension-free repair of peripheral nerve lesions is not possible. The present study was conducted to evaluate the use of nerve conduits by functional and nonfunctional parameters (i.e. histological study). Methods: This experimental study was conducted on 30 male rabbits. After cutting or crushing the right femoral nerve of the rabbits, they were divided into 3 groups: group 1, with right femoral nerve cut; group 2, with right femoral nerve crushed; and group 3, with right femoral nerve cut using a conduit. The 3 groups were evaluated after 1, 8, and 16 weeks for functional parameters (i.e. walking track analysis). In addition, they were subjected to nonfunctional examination (i.e. histological study) after 16 weeks, then, the results were compared. Results: The 3 groups showed no statistically significant differences in motor recovery in the eighth and 16th weeks (p>0.05). Based on the histological study, group 3 with an end-to-end nerve cutting using a conduit, showed a significantly higher axon count compared to groups 2 and 3 (p<0.05). Conclusion: End-to-end anastomosis using conduit led to axon growth; moreover, comparable functional recovery was observed with end-to-end neurorrhaphy in a rabbit model. Given that the diameter of the nerves and muscles, which might be neurotized in humans, and is much bigger and not comparable to that of the rabbits, it is highly recommended to conduct studies on animals with the larger size, such as primates, to facilitate the generalization of the results to humans.

Obstetrical brachial plexus injury (OBPI): Canada's national clinical practice guideline

OBJECTIVE

The objective of this study was to establish an evidence-based clinical practice guideline for the primary management of obstetrical brachial plexus injury (OBPI). This clinical practice guideline addresses 4 existing gaps: (1) historic poor use of evidence, (2) timing of referral to multidisciplinary care, (3) Indications and timing of operative nerve repair and (4) distribution of expertise.

SETTING

The guideline is intended for all healthcare providers treating infants and children, and all specialists treating upper extremity injuries.

PARTICIPANTS

The evidence interpretation and recommendation consensus team (Canadian OBPI Working Group) was composed of clinicians representing each of Canada's 10 multidisciplinary centres.

OUTCOME MEASURES

An electronic modified Delphi approach was used for consensus, with agreement criteria defined a priori. Quality indicators for referral to a multidisciplinary centre were established by consensus. An original meta-analysis of primary nerve repair and review of Canadian epidemiology and burden were previously completed.

RESULTS

7 recommendations address clinical gaps and guide identification, referral, treatment and outcome assessment: (1) physically examine for OBPI in newborns with arm asymmetry or risk factors; (2) refer newborns with OBPI to a multidisciplinary centre by 1 month; (3) provide pregnancy/birth history and physical examination findings at birth; (4) multidisciplinary centres should include a therapist and peripheral nerve surgeon experienced with OBPI; (5) physical therapy should be advised by a multidisciplinary team; (6) microsurgical nerve repair is indicated in root avulsion and other OBPI meeting centre operative criteria; (7) the common data set includes the Narakas classification, limb length, Active Movement Scale (AMS) and Brachial Plexus Outcome Measure (BPOM) 2 years after birth/surgery.

CONCLUSIONS

The process established a new network of opinion leaders and researchers for further guideline development and multicentre research. A structured referral form is available for primary care, including referral recommendations.

Results of nerve reconstructions in treatment of obstetrical brachial plexus injuries

BACKGROUND

The aim of this study was to evaluate the results achieved using various surgical techniques in patients with partial and total obstetrical brachial plexus palsy.

METHODS

From 2000 to 2013, 33 patients with obstetrical brachial plexus injury underwent surgery. Twenty had follow-up periods greater than 24 months and met the criteria for inclusion in the study. All patients were evaluated using the Active Movement Scale.

RESULTS

The outcomes of different nerve reconstructive procedures including nerve transfers, nerve grafting after neuroma resection and end-to-side neurorrhaphy are presented. The overall success rate in upper plexus birth injury was 80 % in shoulder abduction, 50 % in external rotation and 81.8 % in elbow flexion with median follow-ups of 36 months. Success rate in complete paralysis was 87 % in finger and thumb flexion, 87 % in shoulder abduction and 75 % in elbow flexion; the median follow-up was 46 months. Useful reanimation of the hand was obtained in both patients who underwent end-to-side neurotization.

CONCLUSION

Improved function can be obtained in infants with obstetrical brachial plexus injury with early surgical reconstruction.

Intercostal and pectoral nerve transfers to re-innervate the biceps muscle in obstetric brachial plexus lesions

In obstetric brachial plexus lesions with avulsion injury, nerve grafting for biceps muscle re-innervation may not be possible owing to the unavailability of a proximal stump. In such cases, the intercostal nerves or medial pectoral nerve can serve as donor nerves in an end-to-end transfer to the musculocutaneous nerve. The present study reports the results of both techniques from a single institution in a consecutive series of 42 patients between 1995 and 2008. From 1995 to 2000 we always used the intercostal nerve transfer, and from 2001 to 2008 both techniques were used. Biceps muscle force ≥ Medical Research Council Grade 3 was achieved in 37 of 42 patients after a mean follow-up of 44 months. There was no statistical difference in the results in the medial pectoral nerve transfer group (n = 25) and the intercostal nerve transfer group (n = 17).

Utility of delayed surgical repair of neonatal brachial plexus palsy

OBJECT

Neonatal brachial plexus palsy (NBPP) represents a significant health problem with potentially devastating consequences. The most common form of NBPP involves the upper trunk roots. Currently, primary surgical repair is performed if clinical improvement is lacking. There has been increasing interest in "early" surgical repair of NBPPs, occurring within 3-6 months of life. However, early treatment recommendations ignore spontaneous recovery in cases of Erb's palsy. This study was undertaken to evaluate the optimal timing of surgical repair in this group with respect to quality of life.

METHODS

The authors formulated a decision analytical model to compare 4 treatment strategies (no repair or repair at 3, 6, or 12 months of life) for infants with persistent NBPPs. The model derives data from a critical review of published studies and projects health-related quality of life and quality-adjusted life years over a lifetime.

RESULTS

When evaluating the quality of life of infants with NBPP, improved outcomes are seen with delayed surgical repair at 12 months, compared with no repair or repair at early and intermediate time points, at 3 and 6 months, respectively. ANOVA showed that the differences among the 4 groups are highly significant (F = 8369; p < 0.0001). Pairwise post hoc comparisons revealed that there are highly significant differences between each pair of strategies (p < 0.0001). Meta-regression showed no evidence of improved outcomes with more recent treatment dates, compared with older ones, for either nonsurgical or for surgical treatment (p = 0.767 and p = 0.865, respectively).

CONCLUSIONS

These data support a delayed approach of primary surgical reconstruction to optimize quality of life. Early surgery for NBPPs may be an overly aggressive strategy for infants who would otherwise demonstrate spontaneous recovery of function by 12 months. A randomized, controlled trial would be necessary to fully elucidate the natural history of NBPP and determine the optimal time point for surgical intervention.

Nerve growth factor with fibrin glue in end-to-side nerve repair in rats

PURPOSE

To determine the effects of end-to-side nerve repair performed only with fibrin glue containing nerve growth in rats.

METHODS

Seventy two Wistar rats were divided into six equal groups: group A was not submitted to nerve section; group B was submitted to nerve fibular section only. The others groups had the nerve fibular sectioned and then repaired in the lateral surface of an intact tibial nerve, with different procedures: group C: ETS with sutures; group D: ETS with sutures and NGF; group E: ETS with FG only; group F: ETS with FG containing NGF. The motor function was accompanied and the tibial muscle mass, the number and diameter of muscular fibers and regenerated axons were measured.

RESULTS

All the analyzed variables did not show any differences among the four operated groups (p>0.05), which were statistically superior to group B (p<0.05), but inferior to group A (p>0.05).

CONCLUSION

The end-to-side nerve repair presented the same recovery pattern, independent from the repair used, showing that the addition of nerve growth factor in fibrin glue was not enough for the results potentiating.

The embracing end-to-side neurorrhaphy in rats

PURPOSE

Compare two new methods with the traditional end-to-side neurorrhaphy.

METHODS

Rats were divided into four groups. In A-L group the peroneal nerve was sectioned and the distal stump was connected to the lateral of the tibial nerve (donor) with two 10-0 nylon points. In A-R group two perineurium flaps embraced the donor nerve. In the B-R group a suture embraced the donor nerve. Group B-L was the control. After six months tibial cranial muscle mass and morphometry of the distal stump of the peroneal nerve were evaluated.

RESULTS

Muscle mass in groups A-R, A-L and B-R were lower than B-L group (p<0.0001) an equal between themselves (p>0.05). Groups A-R, B-R and A-L had a lower number of nerve fibers when compared with B-L (p=0.0155, p=0.016, p=0.0021).

CONCLUSION

The three types of neurorrhaphy showed no differences related to muscle mass and number of nerve fibers suggesting that the embracing with a single suture has great potential due its simplicity and usefulness in deep areas.

Side-to-Side Nerve Grafts Sustain Chronically Denervated Peripheral Nerve Pathways During Axon Regeneration and Result in Improved Functional Reinnervation

BACKGROUND:

Progressive atrophy of Schwann cells in denervated nerve stumps is a major reason for progressive failure of functional recovery after peripheral nerve injury and surgical repair.

OBJECTIVE:

To examine whether side-to-side nerve bridges between an intact donor nerve and a recipient denervated distal nerve stump promote nerve growth and in turn, protect distal nerve stumps to improve axon regeneration after delayed surgical repair.

METHODS:

In Sprague-Dawley rats, 1 or 3 side-to-side common peroneal (CP) nerve bridges were used to bridge between the donor intact tibial (TIB) nerve and a recipient denervated CP distal nerve stump in the contralateral hind limb. No bridges were placed in control animals. After 4 months, either a fluorescent retrograde dye was applied to back-label TIB motoneurons with axons that had grown into the CP nerve stump or the proximal and distal CP nerve stumps were resutured in experimental and control animals to encourage CP nerve regeneration for 5 months. Retrograde dyes were again applied to count CP motoneurons that regenerated their axons through protected and unprotected nerve stumps.

RESULTS:

Significantly more donor TIB motoneurons regenerated axons into the recipient denervated CP nerve stump through 3 side-to-side CP nerve bridges compared with 1 bridge. This TIB nerve protection significantly increased the number of CP motoneurons regenerating axons through the denervated CP nerve stumps, the number of regenerated axons, and the weight of the reinnervated muscles.

CONCLUSION:

Multiple side-to-side nerve bridges protect chronically denervated nerve stumps to improve axon regeneration and target reinnervation after delayed nerve repair.

Neurotrophin 3 Improves Delayed Reconstruction of Sensory Pathways After Cervical Dorsal Root Injury

BACKGROUND:

Spinal root avulsion, or section, results in devastating functional sequels. Whereas reconstruction of motor pathways based on neurotization can reduce motor deficit, associated permanent limb anesthesia limits expected benefit. Sensory pathway reconstruction after dorsal root injury is limited by the inability of re-growing central sensory axons to enter the spinal cord through an injured root.

OBJECTIVE:

To provide evidence for the reconnection of C7 DRG neurons with the central nervous system (CNS) after experimental section of the C7 dorsal root in adult rats.

METHODS:

We assessed a new reconstruction strategy in adult rats 9 weeks after transection of C6 and C7 dorsal roots. Re-growing C7 central sensory axons were redirected to the noninjured C5 dorsal root through a nerve graft by end-to-side anastomosis that did not alter the C5 conduction properties. In a subgroup of rats, surgical reconstruction was combined with lentivirus-mediated gene transfer to the nerve graft in order to overexpress neurotrophin 3 (NT-3), a neurotrophic factor that stimulates sensory axon regeneration.

RESULTS:

Four months after reconstruction, recording of sensory evoked potentials and fluorescent tracer transport showed electrical and physical reconnection of the C7 dorsal root ganglion neurons to the spinal cord through the reconstructed pathway. Sensory perception recovery predominated on proprioception. Axonal regrowth and perception were improved when the nerve graft overexpressed neurotrophin-3 at the time of transplantation. Neurotrophin-3 overexpression did not persist 4 months after transplantation.

CONCLUSION:

Efficient and functional reconnection of dorsal root ganglion neurons to the spinal cord can be achieved in rats several weeks after cervical dorsal root injury. Surgical repair of sensory pathways could be considered in combination with motor nerve neurotization to treat persisting severe upper limb disability in humans.