Morbidity and mortality in adult spinal deformity surgery: Norwich Spinal Unit experience.

Purpose: This study analyses the complications of spinal deformity surgery in adults to highlight pre-disposing factors.

Methods: The clinical records and imaging were reviewed for 48 consecutive patients, 12 males and 36 females, with a mean age of 64 (31-86), who had surgery for spinal deformity. Mean follow-up time was 36 months (24-60). Patient data recorded were age, diagnosis and co-morbidities; deformity assessment: curve type, sagittal and coronal balance, Cobb angle. Operation details: number of instrumented levels, duration and intra-operative complications.

Outcome: complications, re-operations, balance and Cobb angle.

Results: 28 patients (58 %) had at least 1, 15 patients (27 %) had 2 and 5 patients (9.5 %) had more than 2 co-morbidities. Average time between 1st presentation and operation was 13 months (1-41). The mean number of levels fused was 10.8 (4-23). In addition to posterior pedicle screw instrumentation, 40 patients had chevron osteotomies and 8 had pedicle substraction osteotomies. Posterior interbody fusions were performed at one level in 17 of which 7 had 2 level fusion. Two patients had combined anterior and posterior approaches. Fusion to the pelvis was performed in 19 patients. There were a total of 27 major and minor complications in 19/48 (39.5 %) patients. Late complications included 5 patients who had revisions for proximal junctional kyphosis, 1 patient had revision for pseudoarthrosis and 4 patients had removal of mal-positioned screws.

Conclusions: Factors associated with high complication rate in adult spinal deformity surgery are age, co-morbidities and severe sagittal imbalance at the time of presentation.