Neurological complications after three-column osteotomy in spinal deformity patients with different magnetic resonance imaging -based classification of spinal cord shape

Abstract

Objective: To compare the incidences of neurological complications after three-column osteotomy based on the magnetic resonance imaging(MRI)-based classification of spinal cord shape and cerebrospinal fluid in patients with severe thoracic kyphoscoliosis. Methods: A total of 112 patients (52 males, 60 females, age (M(Q1,Q3)) 13.5 years (9.0-38.5 years)) with thoracic kyphoscoliosis who underwent three-column osteotomy in Nanjing Drum Tower Hospital from August 2015 to August 2018 were retrospectively analyzed. The radiographic parameters including spinal cord morphology at apex, Cobb angle of main curve, distance between C7 plumb line and center sacral vertical line (C7PL-CSVL), global kyphosis (GK) and sagittal vertical axis (SVA) were measured, retrospectively. The Frankel scoring system was used for the evaluation of neurological status at pre-operation, post-operation and the last follow-up. Results: The spinal cord morphologies at apex were classified into type Ⅰ in 8 (7.1%) patients, type Ⅱ in 58 (51.8%), and type Ⅲ in 46 (41.1%), respectively. The patients were followed-up for (28.5±3.4) months. Compared with pre-operation, the Cobb angle of main curve, C7PL-CSVL, GK and SVA showed significantly improvement at post-operation (all P<0.05) and with no significant correction loss at the last follow-up (all P>0.05). New neurological complications were detected in 3 patients with type Ⅱ spinal cord shape, of whom the neurological scores were Frankel D at post-operation. For patients with type Ⅲ spinal cord shape, new neurological complications were detected in 6 patients including 1 Frankel C and 5 Frankel D. In addition, deterioration of neurological status from Frankel D to Frankel C was found in 3 patients with type Ⅲ spinal cord shape. The incidence of new or deteriorating neurological complications in patients with type Ⅲ spinal cord shape was higher than that in type Ⅱ patients (19.6% vs 5.2%, P=0.037). Conclusions: The MRI-based classification is associated with post-operative neurological complications in patients with severe kyphoscoliosis undergoing three-column osteotomy. Patients with type Ⅲ spinal cord shape are at higher risk of post-operative neurological complications.