Background: Conversion rates during minimally invasive surgery are generally examined in the limited scope of a particular procedure. However, for a hospital or payor, the cumulative impact of conversions during commonly performed procedures could have a much larger negative effect than what is appreciated by individual surgeons. The aim of this study is to assess open conversion rates during minimally invasive surgery (MIS) across common procedures using laparoscopic/thoracoscopic (LAP/VATS) and robotic-assisted (RAS) approaches. Study design: Retrospective cohort study using the Premier Database on patients who underwent common operations (hysterectomy, lobectomy, right colectomy, benign sigmoidectomy, low anterior resection, inguinal and ventral hernia repair, and partial nephrectomy) between January 2013 and September 2015. ICD-9 and CPT codes were used to define procedures, modality, and conversion. Propensity scores were calculated using patient, hospital, and surgeon characteristics. Propensity-score matched analysis was used to compare conversions between LAP/VATS and RAS for each procedure. Results: A total of 278,520 patients had MIS approaches of the ten operations. Conversion occurred in 5% of patients and was associated with a 1.77 day incremental increase in length of stay and $3441 incremental increase in cost. RAS was associated with a 58.5% lower rate of conversion to open surgery compared to LAP/VATS. Conclusion: At a health system or payer level, conversion to open is detrimental not just for the patient and surgeon but also puts a significant strain on hospital resources. Use of RAS was associated with less than half of the conversion rate observed for LAP/VATS.

There are few synthetic graft alternatives to treat large long-bone defects resulting from trauma or disease that do not incorporate osteogenic or osteoinductive factors. The aim of this study was to test the additional benefit of including a permeable collagen membrane guide in conjunction with a preformed porous hydroxyapatite bone graft to serve as an improved osteoconductive scaffold for bone regeneration. A 10-mm-segmental long-bone defect model in the rabbit radius was used. The hydroxyapatite scaffolds alone or with a collagen wrap were compared as experimental treatment groups to an empty untreated defect as a negative control or a defect filled with autologous bone grafts as a positive control. All groups were evaluated after 4 and 8 weeks of in vivo implantation using microcomputed tomography, mechanical testing in flexure, and histomorphometry. It was observed that the use of the wrap resulted in an increased bone volume regenerated when compared to the scaffold-only group (59% greater at 4 weeks and 27% greater after 8 weeks). Additionally, the increase in density of the regenerated bone from 4 to 8 weeks in the wrap group was threefold than that in the scaffold group. The use of the collagen wrap showed significant benefits of increased interfacial bone in-growth (149% greater) and periosteal remodeling (49%) after 4 weeks compared to the scaffold-alone with the two groups being comparable after 8 weeks, by when the collagen membrane showed close-to-complete resorption. While the autograft and wrap groups showed significantly greater flexural strength than the defect group after 8 weeks, the scaffold-alone group was not significantly different from the other three groups. It is most likely that the wrap shows improvement of function by acting like a scaffold for periosteal callus ossification, maintaining the local bone-healing environment while reducing fibrous infiltration (15% less than scaffold only at 4 weeks). This study indicates that the use of a collagen membrane with a hydroxyapatite structural graft provides benefits for bone tissue regeneration in terms of early interfacial integration.

Background: We sought to evaluate trends and clinical and economic outcomes between robotic-assisted lobectomy (RL), video-assisted thoracoscopic lobectomy (VL), and open pulmonary lobectomy (OL). Methods: Patients who underwent a lobectomy for malignancy from January 1, 2008, to September 30, 2015, were identified in the Premier Healthcare Database. Propensity score matched (PSM) comparisons were performed between RL versus VL and RL versus OL. Patient characteristics were applied to generate propensity scores. In-hospital and perioperative 30-day outcomes and costs were compared within matched cohorts. Results: From 2008 to 2015, there was a marked decline for OL (71% to 43%, P<0.0001) with a significant increase in RL (1% to 17%, P<0.0001) and VL (28% to 41%, P<0.0001). In the early period (January 2008 to December 2012), total operating room time was longer (P<0.0001) and admission to ICU was more common for RL compared to VL or OL (P<0.0001) although the total length of ICU stay was shorter for RL compared to VL or OL (P<0.0001). In the late period (January 2013 to September 2015), RL was associated with significantly lower rates of complications (P25 lobectomies were performed annually, the total cost of RL was comparable to VL (P=0.09) and OL (P=0.11). Conclusions: During the study period, the utilization of RL increased substantially and was associated with improved perioperative outcomes compared with VL and OL. When annual hospital volume was >25 cases, these clinical advantages persisted and there was no significant cost difference between RL, VL, or OL. RL is an effective and cost-comparable approach for lobectomy in patients with lung malignancy.

To examine the effect of scaffold pore size on bone regeneration within hydroxyapatite scaffolds in large segmental defects, this study evaluated two porous interconnected architectures having similar porosity and strut thickness but different pore sizes. Using a 10 mm segmental rabbit radius defect model, a bilayer scaffold architecture mimicking the cortical-cancellous organization of bone (pore size 200 µm outer layer, 450 µm inner layer) was compared to a purely trabecular-like architecture (pore size 340 µm) and an untreated defect. Bone regeneration was measured using micro-computed tomography and histology after four and eight weeks of in vivo implantation, and the mechanical strength of the defect site after eight weeks’ implantation was assessed using flexural testing. Although both bilayer and trabecular architectures promoted bone growth, the trabecular scaffolds were observed to have more uniform new bone distribution within the scaffold interior at four weeks and greater bone regeneration overall after eight weeks’ implantation (149 ± 9 mm³ compared to 121 ± 8 mm³ in the bilayer and 66 ± 14 mm³ in the defect). Additionally, the trabecular scaffolds were observed to exhibit significantly greater flexural strength (124% increase) and toughness (388% increase) when compared to the empty defects after eight weeks’ implantation. It was concluded from this study that a larger uniform pore size led to greater functional bone regeneration over a longer implantation period for large segmental defects.