What Are Risk Factors for an Ileus After Posterior Spine Surgery?—A Case Control Study

Study design: Case-Control Study. Objective: The purpose of this retrospective study is to evaluate risk factors for developing a postoperative ileus after posterior spine surgery. Methods: Patient charts, including radiographs were evaluated retrospectively. Diagnosis of an ileus was confirmed radiographically by a CT scan in all cases. The control group was retrieved by selecting a random sample of patients undergoing posterior spine surgery who did not develop bowel dysfunction postoperatively. Results: A total of 40 patients had a postoperative ileus. The control group consisted of 80 patients. Both groups did not differ significantly in age, gender, BMI, tobacco use, comorbidities or status of previous abdominal surgery. Significant differences between the 2 groups was the length of stay (5.9 vs. 11.2; p = 0.001), surgery in the lumbar spine (47.5% vs. 87.5%; p < 0.001) and major spine surgery involving > 3 levels (35.0% vs. 57.5%; p = 0.019). Patients who suffered from an ileus were more likely to be treated in ICU (23.8% vs. 37.5%; p = 0.115), being re-admitted (0.0% vs 5.0%; p = 0.044) and having a delayed discharge (32.5% vs. 57.5%; p = 0.009). Multivariable analysis demonstrated that lumbar spine surgery compared to thoracic and/or cervical spine surgery (p = 0.00, OR 8.7 CI 2.9-25.4) and major spine surgery involving > 3 levels (p = 0.012; OR 3.0, CI 1.3-7.2) are associated with developing an ileus postoperatively. Conclusion: Surgeries of the lumbar spine as well as those involving > 3 levels are associated with developing a postoperative ileus. Further studies are needed to expand on possible risk factors and to better understand the mechanism underlying postoperative ileus in spine surgery patients.

Skipping Cross Links in Posterior Spine Surgery: A Review

Background and Aim: Given the conflicting and unreliable evidence for using cross-links in posterior spine surgery, this review was conducted to highlight the different features and usefulness of these augmentation devices in spine surgeries. Methods and Materials/Patients: After searching databases using specific keywords, the relevant articles were ultimately selected and evaluated. Results: Biomechanically investigating the use of cross-links has not resulted in unanimous explanations for their effect. The site and direction of cross-links have been rarely investigated in the literature. Some studies recommended eliminating their application from clinical practice; nevertheless, these studies do not necessarily yield clinical benefits. Posterior spinal fixation with pedicle screws and without cross-links offers stability in all the planes in most clinical conditions. Conclusion: Excluding the cross-links in posterior spine surgery may shorten the operation time and reduce hospital costs. Researchers have reported other problems for cross-links such as late pain, device failure, infections, device prominence, and pseudarthrosis which may be obliterated through the avoidance of their combination in a spinal construct; nevertheless, the results of animal models of the application of special cross-links in a degenerative disorder or deformity suggest that diagonal cross-links provide the highest stability of the construct if they are matched with a rodonly system or with transverse cross-link constructs resulting in a rectangular configuration.

Effects of ventilatory strategy on arterial oxygenation and respiratory mechanics in overweight and obese patients undergoing posterior spine surgery

Prolonged inspiratory to expiratory (I:E) ratio ventilation may improve arterial oxygenation or gas exchange and respiratory mechanics in patients with obesity. We performed a randomised study to compare the effects of the conventional ratio ventilation (CRV) of 1:2 and the equal ratio ventilation (ERV) of 1:1 on arterial oxygenation and respiratory mechanics during spine surgery in overweight and obese patients. Fifty adult patients with a body mass index of ≥25 kg/m2 were randomly allocated to receive an I:E ratio either l:2 (CRV; n = 25) or 1:1 (ERV; n = 25). Arterial oxygenation and respiratory mechanics were recorded in the supine position, and at 30 minutes and 90 minutes after placement in the prone position. The changes in partial arterial oxygen pressure (PaO2) over time did not differ between the groups. The changes in partial arterial carbon dioxide pressure over time were significantly different between the two groups (P = 0.040). The changes in mean airway pressure (Pmean) over time were significantly different between the two groups (P = 0.044). Although ERV provided a significantly higher Pmean than CRV during surgery, the changes in PaO2 did not differ between the two groups.