Table 1. Causes of extraspinal sciatic neurapathy.

Traumatic causes	Intramuscular injection, abdominal surgical procedures, fracture, haematoma
Infective causes	Abscess (e.g. psoas abscess, tubo-ovarian abscess and pelvic abscess)
Inflammatory causes	Sacroiliitis
Tumoral causes
Primary tumours of the sciatic nerve	Schwannoma, neurofibromatosis, neurolymphomatosis and malignant neurofibrosarcoma
Tumours causing compression or invasion of the sciatic nerve	Intra-abdominal or intrapelvic benign or malignant masses, primary (benign or malign) or secondary tumours originating from neighbouring soft tissues and osseous structures along the course of the sciatic nerve and lymphoma
Tumours causing infiltration of the sciatic nerve	Endoneural metastasis and lymphoma
Vascular causes	Aneurysma, arteriovenous malformation and arteriovenous fistulae
Other causes	Endometriosis, leiomyoma, adenomyosis, retroverted uterus, endosalpingitis, haematocolpos, piriformis syndrome, pregnancy, radiotherapy, osteoarthritis