Abstract: Objective  To explore the guiding role of CT classification in endoscopic decompression surgery for patients with lumbar spinal stenosis(LSS). 
Methods  In total, 64 LSS patients were selected and all received CT examination before operation. With results of surgical and pathological classification as the gold standard, the consistency between CT classification results and results of surgical and pathological classification was analyzed, and the selection of surgical methods and postoperative results were analyzed. 
Results  CT diagnosis showed that there were 19 cases of type Ⅰ, 30 cases of type Ⅱ and 15 cases of type Ⅲ among the 64 patients. The pathological results showed that there were 18 cases of type Ⅰ, 30 cases of type Ⅱ and 16 cases of type Ⅲ among the 64 patients. The coincidence rate between CT classification and surgical and pathological classification was 98.44%; the accuracy of CT in diagnosing type Ⅰ, type Ⅱ and type Ⅲ LSS were 98.44%, 100.00% and 98.44%, respectively, and the Kappa values of consistency test with the results of surgical and pathological classification were 0.962, 1.000 and 0.957, respectively(P＜0.001). Of 64 patients, 18 patients with type Ⅰ underwent discectomy via translaminar approach; 30 patients with type Ⅱ underwent modified TESSY technique combined with nerve root decompression under foraminal microscopy; among the 16 patients with type Ⅲ LSS, 4 patients received modified TESSY technique combined with nerve root decompression under foraminal microscopy, and 12 patients received surgery via interlaminar approach. All patients had no postoperative complications such as permanent nerve injury and infection, and the clinical symptoms such as intermittent claudication, leg pain and lumbosacral pain were significantly relieved. 
Conclusion  The accuracy of preoperative CT classification of LSS patients is relatively high, which has certain guiding significance for the selection of percutaneous endoscopic surgical approach in clinical practice.

Key words: spinal stenosis, CT , classification, percutaneous endoscopic decompression surgery