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OBJECTIVES: Percutaneous pedicle instrumentation (PPI) has been used for the treatment of thoracic and thoracolumbar (TL) trauma. However, the ability of PPI to correct significant post-traumatic kyphosis requires further investigation. The objective of this study is to compare the amount of kyphosis correction achieved by PPI vs the traditional open posterior approach in patients presenting with significant kyphotic deformity following traumatic thoracic and TL spine injuries. METHODS: Following Institutional Review Board approval, patients who underwent surgery for thoracic (T1-T9) or TL (T10-L2) fractures with at least 15° of focal kyphosis in a 5-year period were included in this study. Patients were separated into 2 cohorts based on surgical technique: traditional open posterior approach and minimally invasive PPI. Kyphosis correction was measured using Cobb angle 1 vertebrae above and 1 below the level of injury on sagittal preoperative computed tomography image, immediate and follow-up postoperative upright lateral radiographs. Initial degree of correction and loss of correction at the final follow-up were compared. RESULTS: Of 91 patients included, 65 (71%) underwent open surgery and 26 (29%) underwent PPI. Open patients had 11° (95% CI, 9°-13°) of immediate correction compared with 11° (95% CI, 6°-15°) for PPI (P = 0.81). Follow-up data were available for 70 patients with a median of 105.5 days. Both groups had 1° (95% CI, 0°-2°) of loss of correction at follow-up (P = 0.82). Regardless of surgical technique, obesity (>30 kg/m2) and AO type-A compression fractures had significantly less correction. For each unit of body mass index, there was a 0.75° decrease in correction achieved (P < 0.0001). Other factors did not influence the degree of correction. CONCLUSIONS: PPI techniques provide equivalent postoperative angular correction and maintenance of correction compared with open surgery in thoracic and TL trauma patients. CLINICAL RELEVANCE: This study provides evidence for spine surgeons to utilize either technique for treating significant traumatic kyphotic deformity. LEVEL OF EVIDENCE: Therapeutic 3.
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STUDY DESIGN: Cost-effectiveness analysis. OBJECTIVE: To determine if bariatric surgery prior to posterior lumbar decompression and fusion (PLDF) for degenerative spondylolisthesis (DS) is a cost-effective strategy. SUMMARY OF BACKGROUND DATA: Obesity poses significant perioperative challenges for DS. Treated operatively, obese patients achieve worse outcomes relative to non-obese peers. Concomitantly, they fare better with surgery than with nonoperative measures. These competing facts create uncertainty in determining optimal treatment algorithms for obese patients with DS. The role of bariatric surgery merits investigation as a potentially cost-effective optimization strategy prior to PLDF. METHODS: We simulated a Markov model with two cohorts of obese individuals with DS. 10,000 patients with body mass index (BMI) more than or equal to 30 in both arms were candidates for both bariatric surgery and PLDF. Subjects were assigned either to (1) no weight loss intervention with immediate operative or nonoperative management ("traditional arm") or (2) bariatric surgery 2 years prior to entering the same management options ("combined protocol").Published costs, utilities, and transition probabilities from the literature were applied. A willingness to pay threshold of $100,000/QALY was used. Sensitivity analyses were run for all variables to assess the robustness of the model. RESULTS: Over a 10-year horizon, the combined protocol was dominant ($13,500 cheaper, 1.15 QALY more effective). Changes in utilities of operative and nonoperative treatments in non-obese patients, the obesity cost-multiplier, cost of bariatric surgery, and the probability of success of nonoperative treatment in obese patients led to decision changes. However, all thresholds occurred outside published bounds for these variables. CONCLUSION: The combined protocol was less costly and more effective than the traditional protocol. Results were robust with thresholds occurring outside published ranges. Bariatric surgery is a viable, cost-effective preoperative strategy in obese patients considering elective PLDF for DS.Level of Evidence: 3.