Anatomical etiology of “pseudo-sciatica” from superior cluneal nerve entrapment: a laboratory investigation

Abstract

ObjectiveThe superior cluneal nerve (SCN) may become entrapped where it pierces the thoracolumbar fascia over the iliac crest; this can cause low back pain (LBP) and referred pain radiating into the posterior thigh, calf, and occasionally the foot, producing the condition known as “pseudo-sciatica.” Because the SCN was thought to be a cutaneous branch of the lumbar dorsal rami, originating from the dorsal roots of L1–L3, previous anatomical studies failed to explain why SCN causes “pseudo-sciatica”. The purpose of the present anatomical study was to better elucidate the anatomy and improve the understanding of “pseudo-sciatica” from SCN entrapment.Materials and methodsSCN branches were dissected from their origin to termination in subcutaneous tissue in 16 cadavers (5 male and 11 female) with a mean death age of 88 years (range 81–101 years). Special attention was paid to identify SCNs from their emergence from nerve roots and passage through the fascial attachment to the iliac crest.ResultsEighty-one SCN branches were identified originating from T12 to L5 nerve roots with 13 branches passing through the osteofibrous tunnel. These 13 branches originated from L3 (two sides), L4 (six sides), and L5 (five sides). Ten of the 13 branches showed macroscopic entrapment in the tunnel.ConclusionThe majority of SCNs at risk of nerve entrapment originated from the lower lumbar nerve. These anatomical results may explain why patients with SCN entrapment often evince leg pain or tingling that mimics sciatica.

One of the Overlooked Causes of Low Back Pain: Superior Cluneal Nerve Entrapment Neuropathy

“…Buranın lokalizasyonu orta hatta spinöz çıkıntıların 7-8 cm lateralinde iliyak krest üzerindedir. [4][5][6][7][8][9][10][11][12][13][14][15][16] Anatomi çalışmalarında SKS'nin mediyal dalının osteofibröz tünelden geçmesi ile ilgili tartışmalı veriler vardır. Bazı çalışmalarda, SKS'nin bütün dallarının iliyak krest üzerinde torakolomber fasiyayı deldiği gösterilmiş; karşıt olarak başta Maigne olmak üzere, bazı araştırmacılar tüm mediyal dalların osteofibröz tünelden geçtiğini rapor ederken, diğer bazı araştırmacılar ise mediyal, intermediate ve lateral dalların azalan oranlarda bu tünelden geçtiğini raporlamışlardır.…”

“…Son anatomi çalışmasında ise Konno, SKS'nin T12-L5 tüm sinir köklerinden köken aldığını ve ayrıca osteofibröz tünelden geçen sinir dallarının özellikle L4-L5 spinal sinir köklerinden orijin aldığını göstermiş ve böylece SKS tuzaklanmasının siyatiği taklit eden bacak semptomlarına yol açması anlaşılabilmiştir. 4 Anatomi çalışmalarında SKSTN, örnek vakalarda %1,8-13 oranında tespit edilmiştir. [5][6][7][8][9][10][11][12] EPiDEMiyOLOji SKSTN prevalansını değerlendiren çok az çalışma mevcuttur.…”

“…de küçümsenmeyecek bir oranda bel ve bacak ağrısına yol açtığını göstermektedir. [4][5][6][7][8][9][10] Fizik tedavi ve rehabilitasyon hekimlerinin ve spinal cerrahların bu klinik antite ile ilgili farkındalıklarının artması, bel ve bacak ağrılarındaki gereksiz spinal cerrahiyi engelleyecektir.…”

From “Ultrasound Imaging” to “Ultrasound Examination”: A Needful Upgrade in Musculoskeletal Medicine

“…2, 3 Unlike the previous classical descriptions in anatomical textbooks, detailed cadaveric studies have identified not a single medial branch of the SCN passing through the well-known osteo-fibrous tunnel, but multiple tiny branches (variously anastomized like a small nervous plexus) instead. 4 It has also been suggested that such a thin neural network can act as a potential pain generator, not necessarily with the presence of compression in the osteofibrous tunnel, but simply due also to an excessive friction/irritation under the thoracolumbar fascia during lumbar spine movements. 4 In fact, it is well known that neuropathic pain can be generated by neuro-inflammation of a nerve root/peripheral nerve without any compression but simply via chemical mediators and inflammatory cytokines (ie, chemical neuritis/ radiculitis).…”

“…4 It has also been suggested that such a thin neural network can act as a potential pain generator, not necessarily with the presence of compression in the osteofibrous tunnel, but simply due also to an excessive friction/irritation under the thoracolumbar fascia during lumbar spine movements. 4 In fact, it is well known that neuropathic pain can be generated by neuro-inflammation of a nerve root/peripheral nerve without any compression but simply via chemical mediators and inflammatory cytokines (ie, chemical neuritis/ radiculitis). 5 This condition may be evoked by several types of mechanical stress on the neural tissues, such as tension, twist, and friction.…”