[Diagnosis, treatment and etiology analysis of nerve compression by bone fragment after lumbar spine surgery].

Objective: To explore the diagnosis, treatment, cause and prevention of nerve compression by bone fragment after lumbar spine surgery.

Methods: The clinical data of 23 patients with nerve compression by bone fragment after lumbar spine surgery from February 2012 to March 2019 were collected retrospectively, including 9 males and 14 females, aged 42 to 81 years with an average of (62.60±5.70) years. The surgical methods included lumbar interbody fusion in 20 cases and spinal endoscopy in 3 cases. All 23 patients experienced radiating pain on the decompression side or the contralateral limb after operation. The time of occurrence was from immediately after operation to 2 weeks after operation, with an average of (3.2±1.7) days. All patients underwent postoperative examination of lumbar spine CT or MRI to confirm residual ectopic bone fragments, and at the same time, bilateral lower extremity color Doppler ultrasound excluded thrombosis. Sources of ectopic bone fragments:14 cases of residual bone fragments caused by intervertebral fusion bone graft loss or fenestration fusion, 6 cases of fractured upper articular process head, and 3 cases of upper articular process bone remaining during spinal endoscopic surgery.

Results: The patient's hospital stay was 10 to 37 (23.4±6.2) days. All patients were followed up for 6 to 25 (13.6±3.4) months. Three patients underwent posterior open nerve root exploration for removing bone fragments on the same day or the second day after surgery, and the symptoms were relieved. Twenty patients underwent conservative treatment firstly, and 13 patients were discharged after pain relieved by conservative treatment, 7 patients failed conservative treatment, the 2 cases of failed 7 cases had undergone nerve root block surgery during conservative treatment. Two patients underwent spinal endoscopy nerve root exploration and bone mass removal, and five patients underwent posterior open nerve root exploration and bone fragmentation removal. All postoperative pain symptoms were relieved. Preoperative CT, MRI and intraoperative bone fragment removal confirmed the shape and location of the bone fragments. The most likely source of bone fragments was the loss of intervertebral fusion bone grafts or residual bone fragments resulting from fenestration fusion (14 cases), fractured upper articular process head (6 cases), and upper articular process bones remaining in endoscopic surgery (3 cases). According to the Macnab criteria in evaluating clinical outcome, 20 cases got excellent results and 3 good.

Conclusion: After the lumbar spine surgery, the nerve compression by bone fragments is treated with appropriate treatments, and good clinical results can be obtained. Timely removal of residual bone fragments during operation and careful exploration of nerve roots before closing incision can avoid such complications.