What is the prognosis of spinal accessory (SAN) injury?

Updated: Feb 09, 2018
  • Author: Rohan R Walvekar, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Several factors affect spinal accessory nerve (SAN) function after injury such as the extent of injury, type of neck dissection, radiation therapy, interval between injury and repair, length or the vascularity of the graft. [37] Nerve repair with rehabilitation reduces pain, improves shoulder function, and quality of life. [1] Maintaining a high index of suspicion and accepting iatrogenic trauma as a possible cause of persistent shoulder symptoms is important. This approach will lead to early intervention, improved outcomes, and a better patient-physician relationship.

A study by Eickmeyer et al found that in 5-year, disease-free survivors of head and neck cancer, those who underwent SAN-sparing neck dissection had a higher level of functioning than did patients who were treated with SAN-sacrificing neck dissection, with shoulder flexion and abduction being poorest in the latter group. In addition, a correlation was found between reduced scores on quality-of-life measures and decreased shoulder flexion and abduction. Patients in the study who underwent no neck dissection had the highest level of function. [58]

A study by Park et al of patients who sustained iatrogenic SAN injury during lymph node biopsy found that, among 41 patients who underwent end-to-end repair and 82 patients treated with graft repair, 90% and 85%, respectively, achieved at least grade 3 recovery, as measured using the Louisiana State University Health Science Center (LSUHSC) grading system. Among 29 patients who underwent neurolysis—all of whom were treated with this modality when the SAN “was found in continuity with recordable nerve action potential (NAP) across the lesion”—more than 95% achieved LSUHSC grade 3 recovery or above. [59]

A study by Göransson et al found that at an average 10.2 years postoperatively, patients who had undergone either neurolysis, direct nerve repair, or nerve grafting for SAN injury achieved improvement in the mean active range of shoulder movement of, respectively, 44° (43%), 59° (71%), and 30° (22%). Atrophy of the trapezius muscle was absent or modest in, respectively, 75%, 44%, and 50% of patients, while pain was absent or controllable in, respectively, 63%, 56%, and 50% of patients. The study involved a total of 37 patients, with postinjury time to surgery ranging from 2-120 months. [60]

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