Low back pain due to superior cluneal nerve entrapment: A clinicopathologic study.

Abstract

We studied the clinical and nerve pathologic features in 6 patients whose low back pain (LBP) was relieved by superior cluneal nerve (SCN) neurectomy to determine whether nerve compression was the mechanism underlying this type of LBP. All 6 patients (7 nerves) underwent SCN neurectomy for intractable LBP. Their clinical outcomes and the pathologic features of 7 nerves were reviewed. All patients reported LBP relief immediately after SCN neurectomy. Pathologic study of the 7 resected nerves showed marked enlargement, decreased myelinated fiber density, an increase in thinly myelinated fibers (n = 2), perineurial thickening (n = 5), subperineurial edema (n = 4), and Renaut bodies (n = 4). At the distal end of 1 enlarged nerve, we observed a moderate reduction in the density and marked reduction in the number of large myelinated fibers. The pathologic findings and effectiveness of neurectomy suggest that, in our patients, SCN neuropathy likely elicited LBP via nerve compression. Muscle Nerve 57: 777-783, 2018.