The superior cluneal nerves are the cutaneous branches of the posterior rami of L1, L2, and L3, crossing the iliac crest to supply the skin over the superior and lateral gluteal region, from the posterior midline to the greater trochanter. They pierce the thoracolumbar fascia at fixed points approximately 7 cm lateral to the posterior midline as they cross the iliac crest.
Superior cluneal nerve entrapment is an underrecognised cause of low back and buttock pain, producing a characteristic tender point approximately 7 cm lateral to the posterior midline at the iliac crest where the nerves pierce the dense thoracolumbar fascia. Pain may radiate to the lateral buttock and posterior thigh, mimicking disc-related sciatica. Diagnostic injection with local anaesthetic at this point confirming pain relief supports the diagnosis. Treatment includes corticosteroid injection and surgical decompression for refractory cases. The iliac crest harvest for bone graft risks injury to these nerves, producing persistent donor site pain.
Compression of the superior cluneal nerves at their fascial exit point on the iliac crest produces chronic low back and lateral buttock pain, a tender point at the crest, and pain relief with local anaesthetic block, managed with injection or decompression if conservative measures fail.
Bone graft harvest from the posterior iliac crest damages the superior cluneal nerves crossing the crest, producing persistent posterior donor site pain in 10-20% of patients, often more troublesome than the index spinal procedure.
