Can Sensory and Motor Collateral Sprouting be Induced from Intact Peripheral Nerve by End-to-Side Anastomosis?

Abstract

The possibility that collateral sprouting could occur from intact axons in an undamaged sciatic nerve was studied in the rat by suturing either a 7-day predegenerated or a fresh nerve segment in an end-to-side fashion to the sciatic nerve proper. Following a 14- or 35-day recovery period, the pinch reflex test was performed on the transplanted segment to demonstrate the presence of sensory axons. The majority of cases, using a predegenerated nerve segment but not a fresh segment, responded positively. Neurofilament staining and histological examination confirmed the presence of axons in the attached nerve segment. In another series of experiments, the proximal peroneal fascicle was ligated and cut. Following a 7-day predegeneration period the distal stump was sutured end-to-side to the ipsilateral tibial fascicle. After 90 days, stimulation of the tibial nerve proximal to the attached site induced substantial contraction in both the native gastrocnemius muscle and the foreign tibialis anterior muscle. These findings suggest that collateral sprouting may occur from intact axons, perhaps induced by factors emanating from the attached nerve segment, and subsequently make functional peripheral connections.

Axotomy or compression is required for axonal sprouting following end-to-side neurorrhaphy

“…This is an issue whether axons regenerate into the recipient limb as collateral sprouts in response to diffusible factors (Lundborg, et al 1994), or as regenerative sprouts in response to injury. Our data showed that axons rapidly regenerated into the ETS repair following epineurotomy, and by 60 days reached motor targets ~3.1 cm away (median length 2.3 cm).…”

Influence of Breaching the Connective Sheaths of the Donor Nerve on Its Myelinated Sensory Axons and on Their Sprouting into the End-to-Side Coapted Nerve in the Rat

“…51 Accordingly, the number of nerve fibers entering the recipient nerve from the mixed donor nerve was higher after making either an epineurial or perineurial window than after the nerve coaptation with epineurial suturing only, resulting in more effective muscle reinnervation during the first 3 months after end-to-side nerve coaptation. 12,13,29,[48][49][50]54 but not later from 4 up to 8 months after surgery. 16,51,53,64 Interestingly, if epineurial or perineurial windows were enlarged from 1 to 4 or 5 mm, respectively, then, also, the magnitude of axonal ingrowth into the recipient nerve was increased.…”

“…[1][2][3][4][5][6] Functional motor and sensory reinnervation of target tissue was observed after such nerve repair in experimental mammals. [7][8][9][10][11][12][13][14][15][16] Also, several clinical case series suggest that some patients with extensive nerve injuries in the upper extremity, facial palsy, or neurinoma could benefit by such a treatment, although the results are quite unpredictable. 2,[17][18][19][20][21][22][23][24][25][26][27][28] The basic idea of end-to-side nerve coaptation is to achieve reinnervation of a denervated tissue by the collateral sprouting of uninjured axons from the donor nerve through the distal stump of the injured recipient nerve without sacrificing the innervation of the original targets of the donor nerve.…”

“…This suggests that at least the sprouting sensory axons are able to penetrate the perineurium and epineurium of the donor nerve. 46,47 Creating an epineurial or perineurial window in the donor nerve at the site of end-to-side nerve coaptation with sutures enhanced the sprouting of motor and sensory axons into the recipient nerve in some studies, 12,13,16,29,[48][49][50] but not in others. 35,[51][52][53][54] The effects of either epineurial or perineurial window on the axonal sprouting into the recipient nerve were directly compared in only two studies.…”

Enhanced Sensory Recovery after Median Nerve Epair Using Cortical Audio–Tactile Interaction. A Randomised Multicentre Study

“…Recent advances in neuroscience and cognitive science have opened new possibilities for the future to improve sensory recovery after nerve repair, especially with respect to functional sensibility and, specifically, the capacity for identification and discrimination of touch (Lundborg, 1994;.…”