Surgical treatment of sciatic nerve entrapment syndrome in the outlet of pelvic cavity

Objective To investigate the etiology and clinical diagnostic criteria of sciatic nerve entrapment syndrome in the outlet of pelvic cavity, and establish the indications and methods for surgical treatment. Methods From July 2013 to September 2016, 14 cases of sciatic nerve entrapment syndrome in the outlet of pelvic cavity were analyzed. There were 6 cases of pain and sensory disturbance, 8 cases of combined movement disorder, 14 cases being positive results in limb elevation test, 7 cases being positive results in piriformis muscle tension test. The MRI examination of the pelvic outlet of the sciatic nerve in the unilateral lower extremities was performed in 11 cases, and the positive results were 10 cases, all of which were confirmed by intraoperative surgery. All the 14 cases underwent surgical treatment. Intraoperative exploration confirmed that there were 4 cases of simple piriformis hypertrophy entrapment, 3 cases of muscle hypertrophy combined with nameless band compression, 3 cases of abnormal sciatic nerve branches, 3 cases of transverse action vein compression, 1 case of sacroiliac joint osteophyte hyperplasia, 1 case of piriformis absence combined with gluteal maximus degeneration. All of them were relieved and the piriformis and obturator muscles were cut off. 10 cases were treated with neurolysis. Results The postoperative follow-up ranged from 6 to 48 months with an average of 16 months. There were 7 cases whose symptoms were completely disappeared and being competent for the original job, 6 cases whose symptoms were obviously improved and 1 case whose symptom was partially relieved. Conclusion The sciatic nerve entrapment syndrome in the outlet of pelvic cavity is a common syndrome of lower limb extremity neuralgia with variable etiology. Preoperative sciatic nerve pelvic outlet MRI examination and preoperative diagnostic closure should be the main diagnostic criteria. Attention should be paid to the "double compression" of the high nerve root and sciatic nerve. Surgical release is the most direct and effective method for treatment. Key words: Sciatic nerve; Piriformis muscle syndrome; Diagnosis