Controllable Risk Factors for Neurologic Complications in Posterior Lumbar Interbody Fusion as Revision Surgery.

BACKGROUND: The main concern with revision lumbar surgery is the possibility of neurologic complications. This retrospective study was conducted to clarify the risk factors, especially the effects of nerve stretching, for postoperative neurologic complications in posterior lumbar interbody fusion (PLIF) without excessive nerve retraction by bilateral total facetectomy as revision surgery.

METHODS: Between 2005 and 2015, 50 consecutive patients underwent revision PLIF for recurrent stenosis or recurrent disc herniation. The patients were divided into two groups: patients with neurological complications (NC group) and patients without neurological complications (non-NC group). Radiological examinations to evaluate the magnitude of nerve stretching included the following pre- and postoperative plain radiograph measurements: anterolisthesis at flexion, intervertebral lordosis in the neutral position, and posterior disc height in the neutral position.

RESULTS: Sixteen patients (32%) had neurological complications. The decrease in intervertebral lordosis was significantly greater in the NC group than that in the non-NC group (0.8° vs. -1.5°, P<0.05). Distraction of the posterior disc height was significantly greater in the NC group than that in the non-NC group (5.0 mm vs. 2.6 mm, P < 0.01). Neurological complications were seen in all patients with a decrease in intervertebral lordosis >3° and distraction of the posterior disc height >3 mm.

CONCLUSIONS: Decreased intervertebral lordosis, and distraction of the posterior disc height, which can be controlled by surgeons, appear to be risk factors for neurological complications following revision PLIF. In revision PLIF, surgeons should create segmental lordosis without excessive disc height distraction.