OBJECTIVETo analyze the reasons of intraoperative complications of microendoscopic disectomy (MED) and corresponding preventive measures.

METHODSFrom October 2001 to January 2012, the data of 851 patients with lumbar disc herniation underwent MED were retrospectively analyzed. There were 469 males and 382 females with an average age of 42.5 years ranging 16 to 75. Course of disease was from 1 to 18 months with an average of 3 months. The segments of herniated disc including L3,4 of 24 cases, L4,5 of 418 cases and L5S1 of 409 cases . Main symptoms included low back pain with lower extremity radial pain and numbness. Of them,unilateral lower extremity symptom was in 729 cases and bilateral symptom was in 122 cases. There were at least 2 abnormal signs in the four signs which including feeling anormaly, muscle strength anormaly,dysreflexia and muscle atrophy. Distraction test of nerve was positive. CT or MRI findings must coincide with the clinical symptoms and signs. No lumbar instability,spinal stenosis,the upper lumbar disc herniation or combined with cauda equina nerve syndrome were found in 851 patients. The intraoperative complications were recorded and analyzed for the reasons of the intraoperative complication and related prevention measures.

RESULTSAccording to the Macnab standard,424 cases obstained excellent results, 321 good,106 fair,with excellent and good rate of 87.5%. The result was similar to the traditional open operation. One cases transferred to open operation due to equipment breakdown, case died for myocardial infarction at 11 days after the operation, 2 cases occurred acute epidural hematoma in 1 hour after operation. Injury of dura mate of spinal cord occurred in 28 cases and incidence rate was 3.29%(28/851); traction injury of nerve root occurred in 38 cases and incidence rate was 4.46% (38/851). One case occurred in retroperitoneal hematoma, 2 cases in incomplete cauda equina injury and 2 cases in incomplete nerve root breakage.

CONCLUSIONSkilled endoscopic hemostasis techniques,careful and meticulous operation is very important for the prevention of intraoperative complications. Moreover,timely finding and treating the complications was effective measures to prevent the coniplications.