Anatomical study of middle cluneal nerve entrapment

Abstract

ObjectEntrapment of the middle cluneal nerve (MCN) under the long posterior sacroiliac ligament (LPSL) is a possible, and underdiagnosed, cause of low-back and/or leg symptoms. To date, detailed anatomical studies of MCN entrapment are few. The purpose of this study was to ascertain, using cadavers, the relationship between the MCN and LPSL and to investigate MCN entrapment.MethodsA total of 30 hemipelves from 20 cadaveric donors (15 female, 5 male) designated for education or research, were studied by gross anatomical dissection. The age range of the donors at death was 71–101 years with a mean of 88 years. Branches of the MCN were identified under or over the gluteus maximus fascia caudal to the posterior superior iliac spine (PSIS) and traced laterally as far as their finest ramification. Special attention was paid to the relationship between the MCN and LPSL. The distance from the branch of the MCN to the PSIS and to the midline and the diameter of the MCN were measured.ResultsA total of 64 MCN branches were identified in the 30 hemipelves. Of 64 branches, 10 (16%) penetrated the LPSL. The average cephalocaudal distance from the PSIS to where the MCN penetrated the LPSL was 28.5±11.2 mm (9.1–53.7 mm). The distance from the midline was 36.0±6.4 mm (23.5–45.2 mm). The diameter of the MCN branch traversing the LPSL averaged 1.6±0.5 mm (0.5–3.1 mm). Four of the 10 branches penetrating the LPSL had obvious constriction under the ligament.ConclusionThis is the first anatomical study illustrating MCN entrapment. It is likely that MCN entrapment is not a rare clinical entity.

Superior and Middle Cluneal Nerve Entrapment as a Cause of Low Back Pain

“…The MCN originates at S1–S4 ( Fig. 1 ) [ 12 ]. It passes below and sandwiches the long posterior sacroiliac ligament (LPSL) between the posterior superior iliac spine (PSIS) and the posterior inferior iliac spine (PIIS) and courses over the iliac crest to the buttocks [ 9 , 12 , 13 ].…”

“…It passes below and sandwiches the long posterior sacroiliac ligament (LPSL) between the posterior superior iliac spine (PSIS) and the posterior inferior iliac spine (PIIS) and courses over the iliac crest to the buttocks [ 9 , 12 , 13 ]. Although Tubbs et al [ 9 ] claimed that the MCN cannot be entrapped because it runs superficial to the LPSL, others considered MCN-E possible because the lateral branches of the dorsal sacral rami penetrate the LPSL [ 12 , 13 ]. In patients with LBP the putative cause was MCN-E [ 14 - 16 ].…”

Surgical treatment of middle cluneal nerve entrapment neuropathy: technical note

“…14 It passes through the LPSL between the PSIS and the PIIS, slants over the iliac crest, and runs to the buttocks. 14,18,25 According to Tubbs et al, 25 the nerve cannot be entrapped because it runs superficial to the LPSL. McGrath and Zhang 18 reported that because the MCN penetrates the LPSL, its entrapment can elicit pain.…”

“…McGrath and Zhang 18 reported that because the MCN penetrates the LPSL, its entrapment can elicit pain. In a cadaveric study, Konno et al 14 reported that 30% of the MCNs on 30 sides featured a branch that traversed under the LPSL. Their anatomical findings suggested that MCN-E is not a rare clinical entity.…”

“…During the first operation we performed a single MCN decompression procedure and neglected to explore other MCNs. Konno et al 14 reported that 11% of all MCNs featured 2 branches. Among the 13 sites addressed in our series, 2 featured more than 1 branch (cases 8 and 10).…”