Opioid-Sparing Effects of the Bupivacaine Pleural Catheter in Surgical Decompression of the Thoracic Outlet.

BACKGROUND: Rib resection in thoracic outlet decompression can result in significant postoperative pain requiring high levels of opioid medications. We evaluated the impact of a bupivacaine infusing pleural catheter on postoperative pain and opioid usage in patients undergoing rib resection for thoracic outlet syndrome. We hypothesized that delivery of local anesthetic via the pleural catheter would improve postoperative pain control compared to standard multimodal analgesia, and that the use of the catheter would decrease opioid use during the index hospitalization and prescriptions for opioid pain medications at discharge. METHODS: We conducted a single-center retrospective cohort study of 26 patients who underwent rib resection for thoracic outlet decompression. Primary outcome was opioid consumption during the index hospitalization, measured in morphine milligram equivalents (MME). Secondary outcomes were MME prescribed at discharge and pain scores during the index hospitalization before and after the pleural drain and pleural catheter were removed. RESULTS: Patients in the bupivacaine infusion pleural catheter group (n = 11) had significantly lower MME usage during the index hospitalization (22.5 [1.9, 65.6] vs. 119.8 [76.5, 167.4]), and significantly lower MME prescribed at discharge (0 [0, 37.5] vs. 225 [183, 315]), compared to standard multimodal analgesia in controls (n = 15). Only 3 patients in the bupivacaine pleural catheter group were discharged with any opioid prescriptions (27%), compared to 14 patients in the control group (93%). There was no difference in postoperative pain scores between groups before or after removal of the pleural drain, which was placed in all cases (P = 0.31 and P = 0.76, respectively). CONCLUSIONS: Intraoperative placement of a bupivacaine infusion pleural catheter significantly reduced opioid use during the index hospitalization and opioid prescribing at discharge. Anesthetic infusion pleural catheters should be the treatment modality of choice for postoperative pain management in patients undergoing thoracic outlet decompression.

Changes in intraoperative aortic strain as detected by ultrasound elastography in patients following abdominal endovascular aneurysm repair.

Objective: Predicting success after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms (AAAs) relies on measurements of aneurysm sac regression. However, in the absence of regression, morphometric analysis alone is insufficient to reliably predict the successful remodeling of AAAs after EVAR. Biomechanical parameters, such as pressure-normalized principal strain, might provide useful information in the post-EVAR AAA assessment. Our objective was to assess the feasibility of our novel ultrasound elastography (USE) technique to detect changes in the aortic wall principal strain in patients who had undergone EVAR and determine the temporal nature of the biomechanical changes in the aorta. Methods: USE images were obtained from patients undergoing elective EVAR intraoperatively, immediately before and after endograft implantation, and at their 30-day follow-up. The maximal mean principal strain ( ε ρ + ¯ ) for each scan was assessed using our novel technique, which uses a finite element mesh to track the frame-to-frame displacements of the aortic wall over one cardiac cycle. The ε ρ + ¯ in the user-defined aortic wall was then divided by the pulse pressure at the time of the scan to produce a pressure-normalized strain measurement ( ε ρ + ¯ /PP), a surrogate for tissue stiffness. Paired t tests were used to compare the pre- and postoperative ε ρ + ¯ /PP and the postoperative and 30-day ε ρ + ¯ /PP. Patient 30-day sac regression and endoleak data were collected by a review of 30-day follow-up computed tomography scans. Results: USE analysis of the data from 12 patients demonstrated a significant reduction in aortic wall ε ρ + ¯ /PP (average, 0.191% ± 0.09%/kPa vs 0.087% ± 0.04%/kPa; P = .002) immediately after graft implantation, with a nonsignificant change in the ε ρ + ¯ /PP (0.091% ± 0.04%/kPa vs 0.102% ± 0.05%/kPa; P = .47) from postoperatively to 30-day follow-up. This represents an average 46.5% reduction after stent placement, with a nonsignificant 18.1% increase at 30-day follow-up. All the patients showed sac stability, except for two patients who had demonstrated 7.3-mm and 6.8-mm sac regressions. Conclusions: Our analysis has demonstrated that the presented USE technique is a feasible method for detecting significant reductions in aortic ε ρ + ¯ /PP intraoperatively after EVAR. We found that patients undergoing EVAR will experience large reductions in the ε ρ + ¯ /PP intraoperatively after graft implantation, with stabilization found at their 30-day follow-up. These preliminary data have shown that an intraoperative ε ρ + ¯ /PP reduction could be a promising correlate of post-EVAR aneurysm remodeling. Our results have also suggested that endograft design likely plays a large role in determining the aneurysm biomechanical changes immediately after implantation.