Assessing the efficacy of dissection gestures in robotic surgery.

Our group previously defined a dissection gesture classification system that deconstructs robotic tissue dissection into its most elemental yet meaningful movements. The purpose of this study was to expand upon this framework by adding an assessment of gesture efficacy (ineffective, effective, or erroneous) and analyze dissection patterns between groups of surgeons of varying experience. We defined three possible gesture efficacies as ineffective (no meaningful effect on the tissue), effective (intended effect on the tissue), and erroneous (unintended disruption of the tissue). Novices (0 prior robotic cases), intermediates (1-99 cases), and experts (≥ 100 cases) completed a robotic dissection task in a dry-lab training environment. Video recordings were reviewed to classify each gesture and determine its efficacy, then dissection patterns between groups were analyzed. 23 participants completed the task, with 9 novices, 8 intermediates with median caseload 60 (IQR 41-80), and 6 experts with median caseload 525 (IQR 413-900). For gesture selection, we found increasing experience associated with increasing proportion of overall dissection gestures (p = 0.009) and decreasing proportion of retraction gestures (p = 0.009). For gesture efficacy, novices performed the greatest proportion of ineffective gestures (9.8%, p < 0.001), intermediates commit the greatest proportion of erroneous gestures (26.8%, p < 0.001), and the three groups performed similar proportions of overall effective gestures, though experts performed the greatest proportion of effective retraction gestures (85.6%, p < 0.001). Between groups of experience, we found significant differences in gesture selection and gesture efficacy. These relationships may provide insight into further improving surgical training.

Nephrolithiasis management and outcomes in pediatric patients with limited mobility.

INTRODUCTION AND OBJECTIVES: Pediatric patients with limited lower extremity mobility may be at increased risk of developing nephrolithiasis due to bone mineral metabolic derangements. This study sought to assess whether nephrolithiasis management and related outcomes differ between ambulatory versus non-ambulatory pediatric patients. METHODS: This was a retrospective review of ambulatory and non-ambulatory pediatric patients with nephrolithiasis from 2010 to 2021 from a single tertiary care center. Demographics, surgical history, stone compositions, and 24-h urine data were reviewed. Adjusted logistic and linear regression models were utilized to assess whether mobility status was associated with nephrolithiasis-related management and outcomes, including: age at first stone; requiring surgical intervention for stones; number of surgeries; stone compositions; urine culture results; and completion of 24-h urine studies. RESULTS: Among 339 pediatric patients with nephrolithiasis, 67 (19.8%) were non-ambulatory. In adjusted analyses, non-ambulatory patients had 3.24 times greater odds of requiring surgical intervention for stones (95% CI: 1.93-6.84; p < 0.0001); among those who required surgery, non-ambulatory patients required an average of 0.82 more surgical interventions (95% CI: 0.35-1.30; p = 0.0008) than ambulatory patients. Additionally, non-ambulatory patients had 5.28 times greater odds of having a positive urine culture at the time of surgery (95% CI: 2.35-14.08; p = 0.0001) and were significantly less likely to undergo 24-h urine studies (OR: 0.35; 95% CI: 0.15-0.83; p = 0.02). Stone composition significantly varied by mobility status, with non-ambulatory patients being significantly more likely to form calcium apatite (OR: 5.1; 95% CI: 2.18-11.93; p = 0.0002) or struvite (OR 3.72; 95% CI: 1.18-11.74; p = 0.03) stones, and significantly less likely to form calcium oxalate stones (OR: 0.19; 95 CI: 0.08-0.47; p = 0.0003). Among all patients, age at first stone occurred at a median age of 13.4 years (IQR: 8.2-16.4) and did not significantly differ by mobility status (p = 0.92). CONCLUSIONS: Patients with limited mobility required surgery for nephrolithiasis at significantly higher rates and had different stone compositions than ambulatory patients. Obtaining a 24-h urine study in patients with comorbidities affecting ambulation was uncommon, compared to ambulatory patients. Similarly to ambulatory patients, pediatric patients with limited mobility who develop nephrolithiasis tend to first present with stones in early adolescence.

Two Cases of Impaired Wound Healing Among Patients With Major Head and Neck Free-Flap Reconstruction in the Setting of COVID-19 Infection.

Due to the microvascular effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), head and neck reconstructive surgeries utilizing free tissue transfers may be profoundly affected by SARS-CoV-2 infection in the immediate postoperative period. Our objective is to describe two adult patients who developed SARS-CoV-2 after undergoing relatively uncomplicated segmental mandibulectomies. In both cases, the patients were initially negative for SARS-CoV-2, underwent relatively uncomplicated segmental mandibulectomies with fibula free flap reconstructions, and were later discharged in stable conditions. Both patients subsequently experienced significant infectious sequelae at the donor and recipient sites with near-total split-thickness skin graft loss in the donor sites in the setting of postoperative SARS-CoV-2 infection. The first patient developed sepsis and gangrenous changes to his fibula donor site requiring four operative debridements and partial amputation with subsequent osteomyelitis of the remaining fibula. The second patient experienced dehiscence of the oral fibula free flap as well as a 22 cm phlegmon at the fibula donor site that required surgical debridement. In consideration of these cases, SARS-CoV-2 infection during the immediate postoperative period of head and neck reconstruction procedures may elevate the risk of major wound complications. Special consideration must be taken when performing free tissue transfers during the COVID-19 pandemic.

Functional reconstitution of influenza A M2(22-62).

Amantadine-sensitive proton uptake by liposomes is currently the preferred method of demonstrating M2 functionality after reconstitution, to validate structural determination with techniques such as solid-state NMR. With strong driving forces (two decades each of both [K(+)] gradient-induced membrane potential and [H(+)] gradient), M2(22-62) showed a transport rate of 78 H(+)/tetramer-s (pH(o) 6.0, pH(i) 8.0, nominal V(m)=-114 mV), higher than previously measured for similar, shorter, and full-length constructs. Amantadine sensitivity of the conductance domain at pH 6.8 was also comparable to other published reports. Proton flux rate was optimal at protein densities of 0.05-1.0% (peptide wt.% in lipid). Rundown of total proton uptake after addition of valinomycin and CCCP, as detected by delayed addition of valinomycin, indicated M2-induced K(+) flux of 0.1K(+)/tetramer-s, and also demonstrated that the K(+) permeability, relative to H(+), was 2.8 × 10(-6). Transport rate, amantadine and cyclooctylamine sensitivity, acid activation, and H(+) selectivity were all consistent with full functionality of the reconstituted conductance domain. Decreased external pH increased proton uptake with an apparent pK(a) of 6.