Anterior versus posterior surgery for osteoporotic vertebral collapse with neurological deficit in the thoracolumbar spine

Despite the increasing number of reports on surgical treatments for thoracolumbar osteoporotic vertebral collapse with neurological deficits, the choice of surgery remains controversial. In this retrospective study, we compared the outcomes of posterior and anterior surgeries for single-level osteoporotic vertebral collapse with neurological deficit in the thoracolumbar spine. Both posterior and anterior surgical approaches were performed with a consistent procedure for a single surgical indication at one institution. Twenty-four patients treated with posterior surgery and 28 patients treated with anterior surgery were followed-up over an average of 5 years after surgery. Radiographic results (kyphotic angle, bony fusion, and instrumentation failure), neurological improvement, and surgical complications were compared between the two groups. The average correction angle after surgery was larger in the posterior group than in the anterior group (P = 0.013), but not at final follow-up (P = 0.755). The average loss of correction was also higher in the posterior group than in the anterior group (P = 0.037). There was no significant difference in neurological outcomes between anterior and posterior approaches (P = 0.080). Two-way analysis of variance (ANOVA) showed that the neurological outcome was better in wedge type than in flat type vertebral collapse, regardless of the type of surgical approach (P = 0.0093). In wedge type vertebral collapse, neurological improvement tended to be greater after anterior than after posterior surgery. In four of six cases with instrumentation failure in the anterior group, a titanium cage subsided more than 5 mm but bony fusion was eventually achieved without causing neurological problems. In the posterior group, six cases experienced instrumentation failure during the postoperative course (two cases with screws loosened from pedicles and bodies, and one case with breakage of a screw neck). None of the patients developed instrumentation-related neurological problems. Two cases in each group developed pseudoarthrosis. In single-level osteoporotic vertebral collapse with neurological deficit, anterior surgery tended to improve neurological deficit in wedge type, but not in flat type collapse, compared with posterior surgery.