Zhiyue Shi

Perioperative Major Non-neurological Complications in 105 Patients Undergoing Posterior Vertebral Column Resection Procedures for Severe Rigid Deformities.

Study Design. Retrospective study. Objective. To analyze the perioperative major non-neurological complications (MNNCs) in posterior vertebral column resection (PVCR) procedures for severe rigid deformities and to identify the factors that may increase the risk. Summary of Background Data. Although surgeons constantly attempted to increase the corrective efficacy and neurological safety after PVCR, there are still significant risks of major and potentially life-threatening complications. Methods. A total of 105 consecutive patients with severe rigid deformity who underwent 1-stage PVCR at a single center from 2004 to 2013 were reviewed. The demographic data, medical and surgical histories, perioperative and final follow-up radiographical measurements, and prevalence of perioperative MNNCs were reviewed. Results. The mean age of patients at the time of surgery was 18.9 years (range: 10–45 yr). The major curve of scoliosis was 108.9 ± 25.5 preoperatively and 37.2 ± 16.8 at the final follow-up, and segmental kyphosis was from 89.8 ± 31.1 to 30.4 ± 15.3. There were 31 MNNCs in 24 patients: 16 respiratory complications in 13 patients, 9 cardiovascular adverse events in 7 cases, 1 malignant hyperthermia, and 1 optic deficit. There were 3 patients with wound infection, and 1 of them had to undergo partial removal of the implant for infection control. One patient with neurofibromatosis died 1 day after operation. Factors that showed no relationships with an increased prevalence of MNNCs were age, sex, presence of cardiac disease or neural axis malformation, and both sagittal and coronal correction rate. Patients with T6 and upper resected level, undergoing PVCR at the early period, showed a trend toward more MNNCs encountered. Moreover, nonidiopathic deformity, large scoliotic curve greater than 150°, percent predicated forced vital capacity and forced expiratory volume in 1 second (FEV1.0) less than 40%, and estimated blood loss volume more than 5000 mL were identified as risk factors associated with MNNCs. Conclusion. Patients who had undergone PVCR experienced expected higher rate of MNNCs, with an overall prevalence of 22.9%. When considering PVCR, it is important to recognize the significantly higher inherent risks and provide appropriate preoperative counseling on the risks and benefits of surgery. Level of Evidence: 3

Proper Responding Strategies to Neuromonitoring Alerts During Correction Step in Posterior Vertebral Column Resection Patients With Severe Rigid Deformities Can Reduce Postoperative Neurologic Deficits

Study Design. Retrospective study. Objective. To analyze the intraoperative neuromonitoring (IOM) changes in posterior vertebral column resection (PVCR) for severe rigid deformity patients, and describe our stepwise responding strategies. Summary of Background Data. Obvious neurological deficit risk accompanied with PVCR correction has been emphasized repeatedly. Methods. The records of 46 patients who underwent PVCR achieved IOM were reviewed. IOM alerts triggered responding protocols: (1) exchange the convex corrective rod to concave stabilizing rod, (2) appropriate compression for spinal shortening, (3) reversed in situ rod bending, (4) translation technique and unisegmental derotation, (5) adjacent segmental resection. Results. The overall scoliotic correction rate was 65.4% (from 112 ± 28.6 to 39 ± 13.4) and segmental kyphotic correction rate was 64.2% (from 101 ± 37.3 to 36 ± 19.2). During correction step, somatosensory-evoked potential warning (3) and somatosensory-evoked potential/transcranial motor-evoked potential warning (8) were detected in 11 patients (23.9%). Probable cause identification including rule out IOM technical factors, residual impingement, and if there was unstable spinal column (1), spinal cord excessive tension on concave side (3), and the excessive opposite spinal displacement between two aspects of resected area (7). After rod change (1), compression (2), bending (3), derotation (3), and adjacent resection (2), all IOM changes went to under warning criteria. All 11 patients revealed neurologically intact postoperatively. There was no difference of correction rate between IOMs alert or not. However, adult, extremely severe or sharp angular curves tend to be more common in IOM alert patients. Conclusion. As three-dimensional spinal column divided and relinked in PVCR, and the correction maneuvers were restricted on single dimension, inevitably resulted in spinal cord tension changes and spinal column opposite displacement. To timely identify them, prompt interventions should be performed, and even enlarge the resected area to reduce the abrupt turning tendency of the spinal cord. Level of Evidence: 5