Utilization of Flexible-Wearable Sensors to Describe the Kinematics of Surgical Proficiency.

BACKGROUND: Traditional assessment (e.g., checklists, videotaping) for surgical proficiency may lead to subjectivity and does not predict performance in the clinical setting. Hand motion analysis is evolving as an objective tool for grading technical dexterity; however, most devices accompany with technical limitations or discomfort. We purpose the use of flexible wearable sensors to evaluate the kinematics of surgical proficiency. METHODS: Surgeons were recruited and performed a vascular anastomosis task in a single institution. A modified objective structured assessment of technical skills (mOSATS) was used for technical qualification. Flexible wearable sensors (BioStamp RCTM, mc10 Inc., Lexington, MA) were placed on the dorsum of the dominant hand (DH) and nondominant hand (nDH) to measure kinematic parameters: path length (Tpath), mean (Vmean) and peak (Vpeak) velocity, number of hand movements (Nmove), ratio of DH to nDH movements (rMov), and time of task (tTask) and further compared with the mOSATS score. RESULTS: Participants were categorized as experts (n = 12) and novices (n = 8) based on a cutoff mean mOSATS score. Significant differences for tTask (P = 0.02), rMov (P = 0.07), DH Tpath (P = 0.04), Vmean (P = 0.07), Vpeak (P = 0.04), and nDH Nmove (P = 0.02) were in favor of the experts. Overall, mOSATS had significant correlation with tTask (r = -0.69, P = 0.001), Nmove of DH (r = -0.44, P = 0.047) and nDH (r = -0.66, P = 0.001), and rMov (r = 0.52, P = 0.017). CONCLUSIONS: Hand motion analysis evaluated by flexible wearable sensors is feasible and informative. Experts utilize coordinated two-handed motion, whereas novices perform one-handed tasks in a hastily jerky manner. These tendencies create opportunity for improvement in surgical proficiency among trainees.

Laparoscopic repair reduces incidence of surgical site infections for all ventral hernias.

BACKGROUND: The role of laparoscopic repair of ventral hernias remains incompletely defined. We hypothesize that laparoscopy, compared to open repair with mesh, decreases surgical site infection (SSI) for all ventral hernia types. METHODS: MEDLINE, EMBASE, and Cochrane databases were reviewed to identify studies evaluating outcomes of laparoscopic versus open repair with mesh of ventral hernias and divided into groups (primary or incisional). Studies with high risk of bias were excluded. Primary outcomes of interest were recurrence and SSI. Fixed effects model was used unless significant heterogeneity, assessed with the Higgins I square (I(2)), was encountered. RESULTS: There were 5 and 15 studies for primary and incisional cohorts. No difference was seen in recurrence between laparoscopic and open repair in the two hernia groups. SSI was more common with open repair in both hernia groups: primary (OR 4.17, 95%CI [2.03-8.55]) and incisional (OR 5.16, 95%CI [2.79-9.57]). CONCLUSIONS: Laparoscopic repair, compared to open repair with mesh, decreases rates of SSI in all types of ventral hernias with no difference in recurrence. These data suggest that laparoscopic approach may be the treatment of choice for all types of ventral hernias.

Review of stoma site and midline incisional hernias after stoma reversal.

BACKGROUND: The incidence of incisional hernias after stoma reversal is not well reported. The aim of this study was to systematically review the literature reporting data on incisional hernias after stoma reversal. We evaluated both the incidence of stoma site and midline incisional hernias. METHODS: A systematic review identified studies published between January 1, 1980, and December 31, 2012, reporting the incidence of incisional hernia after stoma reversal at either the stoma site or at the midline incision (in cases requiring laparotomy). Pediatric studies were excluded. Assessment of risk of bias, detection method, and essential study-specific characteristics (follow-up duration, stoma type, age, body mass index, and so forth) was done. RESULTS: Sixteen studies were included in the analysis; 1613 patients had 1613 stomas formed. Fifteen studies assessed stoma site hernias and five studies assessed midline incisional hernias. The median (range) incidence of stoma site incisional hernias was 8.3% (range 0%-33.9%) and for midline incisional hernias was 44.1% (range 8.7%-58.1%). When evaluating only studies with a low risk of bias, the incidence for stoma site incisional hernias is closer to one in three and for midline incisional hernias is closer to one in two. CONCLUSION: Stoma site and midline incisional hernias are significant clinical complications of stoma reversals. The quality of studies available is poor and heterogeneous. Future prospective randomized controlled trials or observational studies with standardized follow-up and outcome definitions/measurements are needed.

Extracellular signal-regulated kinase (ERK) dictates osteogenic and/or chondrogenic lineage commitment of mesenchymal stem cells under dynamic compression.

Elucidating the intracellular signaling cascades which lead to differentiation programs can be a daunting but necessary task. Even more so when the nature of the differentiating stimuli can elicit different biochemical responses yet achieve the same functional outcome. In the field of cartilage and bone regeneration the importance of the extracellular signal-regulated kinase (ERK) pathway has been a controversial issue as of late. Whether differentiation results from a soluble chemical induction or a microenvironmental cue on the cells seems to have a determining effect on the role that this pathway plays in ultimate cell fate. Here we explore the role of the ERK1/2 pathway on the mechanical induction of chondrogenesis of bone marrow mesenchymal stem cells (MSC). The cells were encapsulated in fibrin gel scaffolds and subjected to a dynamic mechanical compression stimulus previously demonstrated to induce chondrogenic differentiation of the cells with and without the addition of PD98059, a selective inhibitor for the ERK1/2 pathway. Samples were then analyzed by RT-PCR and histochemical staining for markers of both chondrogenic and osteogenic differentiation. Our results show that dynamic compression induces the chondrogenic differentiation of the cells and that inhibition of the ERK1/2 pathway completely abolishes this chondrogenic response. On the other hand, inhibition of ERK1/2 under dynamic compression augments the osteogenic response of the cells and significantly increases their expression of alkaline phosphatase (ALP), collagen type I (COLI) and osteocalcin (OCN) (P<0.05). These results were confirmed by the histochemical staining where dynamically compressed samples show staining for sulfated glycosaminoglycans (sGAG) while the inhibited and compressed samples show no sGAG but present positive staining for microcalcifications. These results would suggest that the activation of ERK1/2 can determine the ultimate cell fate between the chondrogenic and osteogenic programs in cells stimulated under dynamic unconfined mechanical compression.

Activation of the extracellular signal-regulated kinases 1 and 2 (ERK1/2) is needed for the TGFß-induced chondrogenic and osteogenic differentiation of mesenchymal stem cells.

The role of the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway on the osteogenesis of progenitor and stem cells has received a lot of attention due to conflicting results in the literature. ERK1/2 has been reported to be both activating and inhibitory to the osteogenesis of different cell types under varying culture conditions. This study focused specifically on the role of ERK1/2 on the chondrogenesis and osteogenesis of mesenchymal stem cells (MSC) induced by cytokine exposure. Bone marrow-derived MSC were cultured in three-dimensional fibrin gel scaffolds and stimulated down the chondrogenic and osteogenic programs by addition of TGF-ß3 to and osteogenic buffer media. Cells were cultured under control conditions (no cytokine supplementation), treated with TGF-ß3 or treated with PD98059+TGF-ß3 for 7 days. RT-PCR results show that addition of TGF-ß3 significantly upregulates the phosphorylation of ERK1/2 and induces the cells down the chondrogenic and osteogenic pathways (as demonstrated by the significant upregulation of aggrecan, sox9, collagen types 1 & 2 gene expressions). Inhibition of ERK1/2 phosphorylation with PD98059 led to the abolishment of the upregulation of chondrogenic and osteogenic-specific gene expressions. These results demonstrate that ERK1/2 is needed for the chondrogenic and osteogenic differentiation of MSC as induced by TGF-ß3 supplementation.

Development and validation of a risk stratification score for ventral incisional hernia after abdominal surgery: hernia expectation rates in intra-abdominal surgery (the HERNIA Project).

BACKGROUND: Ventral incisional hernias (VIH) develop in up to 20% of patients after abdominal surgery. No widely applicable preoperative risk-assessment tool exists. We aimed to develop and validate a risk-assessment tool to predict VIH after abdominal surgery. STUDY DESIGN: A prospective study of all patients undergoing abdominal surgery was conducted at a single institution from 2008 to 2010. Variables were defined in accordance with the National Surgical Quality Improvement Project, and VIH was determined through clinical and radiographic evaluation. A multivariate Cox proportional hazard model was built from a development cohort (2008 to 2009) to identify predictors of VIH. The HERNIAscore was created by converting the hazards ratios (HR) to points. The predictive accuracy was assessed on the validation cohort (2010) using a receiver operator characteristic curve and calculating the area under the curve (AUC). RESULTS: Of 625 patients followed for a median of 41 months (range 0.3 to 64 months), 93 (13.9%) developed a VIH. The training cohort (n = 428, VIH = 70, 16.4%) identified 4 independent predictors: laparotomy (HR 4.77, 95% CI 2.61 to 8.70) or hand-assisted laparoscopy (HAL, HR 4.00, 95% CI 2.08 to 7.70), COPD (HR 2.35; 95% CI 1.44 to 3.83), and BMI ≥ 25 kg/m(2) (HR1.74; 95% CI 1.04 to 2.91). Factors that were not predictive included age, sex, American Society of Anesthesiologists (ASA) score, albumin, immunosuppression, previous surgery, and suture material or technique. The predictive score had an AUC = 0.77 (95% CI 0.68 to 0.86) using the validation cohort (n = 197, VIH = 23, 11.6%). Using the HERNIAscore: HERNIAscore = 4(∗)Laparotomy+3(∗)HAL+1(∗)COPD+1(∗) BMI ≥ 25, 3 classes stratified the risk of VIH: class I (0 to 3 points),5.2%; class II (4 to 5 points),19.6%; and class III (6 points), 55.0%. CONCLUSIONS: The HERNIAscore accurately identifies patients at increased risk for VIH. Although external validation is needed, this provides a starting point to counsel patients and guide clinical decisions. Increasing the use of laparoscopy, weight-loss programs, community smoking prevention programs, and incisional reinforcement may help reduce rates of VIH.