What is the role of neurolysis in the treatment of spinal accessory nerve (SAN) injury?

Updated: Mar 04, 2020
  • Author: Rohan R Walvekar, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Neurolysis is an option for improving nerve function if no anatomical break in continuity of the nerve is found intraoperatively and conduction of electrical impulses is present. Intraoperative stimulation of the SAN should demonstrate transmission of an action potential to the neuromuscular junction, as indicated by trapezius muscle contraction. If the SAN is able to conduct nerve impulses, an extrafascicular neurolysis may be performed. [14, 42] While performing a neurolysis of a scarred segment of the nerve (neuroma), the surgeon must exercise extreme caution because of the risk of damage to underlying functional nerve fibers.

The completion of the neurolysis can be gauged by identifying redundant functional nerve fibers also known as the "bands of Fontana." Under normal circumstances, these bands protect nerve function through their redundancy by permitting physiological nerve stretching. Consequently, preserving these bands during a neurolysis is important. In addition, intraoperative nerve conduction studies, both proximal and distal to the scarred segment of nerve, aid in identification of functional nerve fascicles. [50]

In summary, minimal dissection and neurolysis of a neuroma facilitated by the above techniques is preferred to protect underlying functional nerve fascicles, while nonfunctional fascicles can be bypassed with grafting procedures similar to the ones described below. [50]

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