Intraoperative changes of surgical approach and a second surgery after percutaneous endoscopic surgery for lumbar spinal stenosis.

Objective: To investigate the reasons for a second surgery after Percutaneous Endoscopic Surgery (PES) for lumbar spinal stenosis and to provide references for the choice of indications and appropriate surgical approach.

Method: A total of 426 patients received PES for lumbar spinal stenosis. The postoperative, intraoperative, and postoperative data of the subjects were analyzed. The reasons for intraoperative difficulties, poor outcomes after surgery, and a second surgery were analyzed.

Result: The surgical approach was changed in four out of 426 patients (0.94 %) during surgery, and 6 patients (1.4 %) received a second surgery; 3 out of 4 patients were intraoperatively shifted to PIED using the Delta endoscope, and 1 shifted to ordinary PIED. The reasons for the intraoperative change of surgical approach included severe hyperplasia and obscure anatomic structure in 3 patients and a dural sac tear with neural outflow in 1 patient. The reasons for a second surgery in 19 patients were as follows: nerve entrapment by bone fragments in 1 patient; nerve injury in 3 patients; lumbar instability in 3 patients; untreated or residual Lumbar Intervertebral Disc Herniation (LIDH) in 4 patients; recurrent LIDH in 1 patient; and inadequate decompression in 7 patients.

Conclusion: Severe hyperplasia, obscure anatomic structure, lumbar instability, and nerve injury are the common reasons for a second surgery after PES for lumbar spinal stenosis. Appropriate indications and surgical approaches can be chosen based on the patient's situations and technical conditions.