Optimizing Pedicle Subtraction Osteotomy Techniques: A New Reduction Plier to Increase Technical Safety and Angular Reduction Efficiency.

BACKGROUND: Pedicle subtraction osteotomy (PSO) is a technically demanding surgery. There is room for development of osteotomy reduction instruments like the one we present in this study, to better guide angular correction and closure of the osteotomy line. OBJECTIVE: To present a new surgical instrument that optimizes PSOs of the thoracolumbar spine. METHODS: Seventeen consecutive patients have been treated at 3 different European University Hospitals. All underwent a PSO of the lumbar spine to treat major sagittal imbalance. The amount of vertebral angular correction needed was calculated using the full balance integrated (FBI) method. A special plier, which allows to safely control the angular correction, was used intraoperatively. Preoperative and early postoperative global sagittal balance parameters were compared. RESULTS: The mean preoperative calculated correction angle (FBI) was 33.8°; the mean postoperative correction obtained was 32.1°. Lumbar lordosis was statistically greater than preoperatively (55.8° vs 19.4°, P < .0001). The global sagittal balance was improved, as shown by the increase of the spino-sacral angle from 122° preoperatively to 128° postoperatively (P = .0547). None of the patients had an intraoperative or early postoperative neurologic complication. There were no mechanical intraoperative complications during correction nor at the first postoperative follow-up. CONCLUSION: The advantages of the instrument are safe, precise, and efficient reduction, by a rotation of the pedicle screws close to the osteotomy line, thus avoiding collapse and lack of correction, complications usually seen with the conventional technique. Further prospective studies are needed to confirm these results.

Preoperative embolization in surgical treatment of spinal metastases: single-blind, randomized controlled clinical trial of efficacy in decreasing intraoperative blood loss.

PURPOSE: To assess whether preoperative transcatheter arterial embolization of spinal metastases reduces blood loss, the need for transfusion with allogeneic red blood cells (RBCs), and surgery time in the surgical treatment of patients with symptomatic metastatic spinal cord compression. MATERIALS AND METHODS: This single-blind, randomized (1:1), controlled, parallel-group, single-center trial was approved by the Danish National Committee on Biomedical Research Ethics and was conducted from May 2011-March 2013. Participants (N = 45) were scheduled for decompression and posterior thoracic/lumbar spinal instrumentation and randomly assigned to either preoperative embolization (n = 23) or a control group (n = 22). The primary outcome was intraoperative blood loss. Secondary outcomes were perioperative blood loss, allogeneic RBC transfusion, and surgery time. Analyses were performed by intention-to-treat. RESULTS: The intention-to-treat analysis included 45 patients. Mean intraoperative blood loss did not differ significantly (P = .270) between the embolization group (618 mL [SD, 282 mL]) and the control group (735 mL [SD, 415 mL]). There was also no significant difference in allogeneic RBC transfusion (P = .243). Surgery time was significantly shorter in the embolization group (P = .031): median 90 minutes (range, 54-252 min) versus 124 minutes (range, 80-183 min). The subanalysis of hypervascular metastases revealed a significant (P = .041) reduction in blood loss in the embolization group: 645 mL (SD, 289 mL) versus 902 mL (SD, 416 mL). CONCLUSIONS: Preoperative embolization in patients with symptomatic spinal metastasis independent of primary tumor diagnosis did not reduce intraoperative blood loss and allogeneic RBC transfusion significantly but did reduce the surgery time. A small reduction of intraoperative blood loss was shown in hypervascular metastases.

Inter- and Intra-rater Agreement in Assessment of Adult Spinal Deformity Using the Scoliosis Research Society-Schwab Classification.

STUDY DESIGN: Cross-sectional assessment of inter- and intra-rater agreement. OBJECTIVES: To assess inter- and intra-rater agreement between spine surgeons with different levels of experience in a large consecutive series of adult patients referred to a tertiary institution for evaluation of a spinal deformity using the Scoliosis Research Society (SRS)-Schwab classification. BACKGROUND: The development of the SRS-Schwab classification of adult spinal deformity is based on current knowledge about relevant radiographic variables related to health-related quality of life. Clinical implementation of the classification requires satisfactory reliability. Two recent reports on agreement were based on a small selected case sample using pre-marked radiographs and a large cohort of only surgical patients, including congenital deformity. METHODS: Scoliosis Research Society-Schwab classification of 67 consecutive adult patients referred for surgical evaluation of a spinal deformity was done in a blinded fashion without pre-marking by 2 senior spine surgeons, 1 attending, and 1 spine fellow. After 2 weeks, the classification was repeated on recoded radiographs. Inter- and intra-rater agreement was analyzed using Fleiss kappa statistics. Rater bias was assessed using Bhapkar test for marginal homogeneity. RESULTS: According to Landis and Koch, the observed agreements were considered substantial to almost perfect for curve type and sagittal modifiers and moderate for entire grade, with no consistent differences between surgeons with different levels of experience. CONCLUSIONS: The results for each individual radiographic parameter correspond to previous findings and support use of the SRS-Schwab classification in adult spinal deformity. The results for entire grade were considered only moderate. The authors recommend that it is not used as an individual parameter.