Risk of Neurological Injuries in Spinal Deformity Surgery

A retrospective study.

Rate of neurological injuries is widely reported for spinal deformity surgery. However, few have included the influence of the subtypes and severity of the deformity, or anterior versus posterior corrections. The purpose of this study is to quantify these risks.

The risk of neurological injuries was examined in a single institution. Quantification of risk was made between operations, and for different subtypes of spinal deformity.

Prospectively entered neuromonitoring database between 2006 and 2012 was interrogated, including all deformity cases under 21 years of age. Tumor, fracture, infection, and revision cases were excluded. All major changes in monitoring ("red alerts") were identified and detailed examinations of the neuromonitoring records, clinical notes, and radiographs were made. Diagnosis, deformity severity, and operative details were recorded.

Of 2291 deformity operations, there were 2068 scoliosis (1636 idiopathic, 204 neuromuscular, 216 syndromic, 12 others), 89 kyphosis, 54 growing rod procedures, and 80 operations for hemivertebra. Six hundred ninety-six anterior and 1363 posterior operations were performed for scoliosis (nine not recorded), and 38 anterior and 51 posterior kyphosis corrections. Sixty-seven "red alerts" were identified (62 posterior, five anterior). Average Cobb angle was 88°. There were 14 transient and six permanent neurological injuries. One permanent injury was sustained during kyphosis correction and five during scoliosis correction. Common surgeon reactions after "red alerts" were surgical pause with anesthetic interventions (n = 39) and the Stagnara wake-up test (n = 22). Metalwork was partially removed in 20, revised in 12, and completely removed in nine. Thirteen procedures were abandoned.

The overall risk of permanent neurological injury was 0.2%. The highest risk groups were posterior corrections for kyphosis, and scoliosis associated with a syndrome. Four percent of all posterior deformity corrections had "red alerts," and 0.3% resulted in permanent injuries compared with 0.6% "red alerts" and 0.3% permanent injuries for anterior surgery. The overall risk for idiopathic scoliosis was 0.06%.

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