Simulations of extensional flow in microrheometric devices

We present a detailed numerical study of the flow of a Newtonian fluid through microrheometric devices featuring a sudden contraction–expansion. This flow configuration is typically used to generate extensional deformations and high strain rates. The excess pressure drop resulting from the converging and diverging flow is an important dynamic measure to quantify if the device is intended to be used as a microfluidic extensional rheometer. To explore this idea, we examine the effect of the contraction length, aspect ratio and Reynolds number on the flow kinematics and resulting pressure field. Analysis of the computed velocity and pressure fields show that, for typical experimental conditions used in microfluidic devices, the steady flow is highly three-dimensional with open spiraling vortical structures in the stagnant corner regions. The numerical simulations of the local kinematics and global pressure drop are in good agreement with experimental results. The device aspect ratio is shown to have a strong impact on the flow and consequently on the excess pressure drop, which is quantified in terms of the dimensionless Couette and Bagley correction factors. We suggest an approach for calculating the Bagley correction which may be especially appropriate for planar microchannels

Complex reconstruction with flaps after abdominoperineal resection and groin dissection for anal squamous cell carcinoma: A difficult case involving many specialities

Background: Anal squamous cell carcinoma accounts for about 2–4% of all lower gastrointestinal malignancies, with a distant disease reported in less than 5%. Although surgical treatment is rarely necessary, this often involve large dissections and difficult reconstructive procedures. Case Report: We present a complex but successful case of double-flap reconstruction after abdominoperineal resection and groin dissection for anal squamous cell carcinoma (cT3N3M0) with metastatic right inguinal lymph nodes and ipsilateral threatening of femoral vessels. A multi-specialty team was involved in the operation. A vascular and plastic surgeon performed the inguinal dissection with en bloc excision of the saphenous magna and a cuff of the femoral vein, while colorectal surgeons carried out the abdominoperineal excision. The 2 large tissue gaps at the groin and perineum were covered with an oblique rectus abdominis myocutaneous flap and a gluteal lotus flap, respectively. A partially absorbable mesh was placed at the level of the anterior sheath in order to reinforce the abdominal wall, whereas an absorbable mesh was used as a bridge for the dissected pelvic floor muscles. The post-operative period was uneventful and the follow-up at 5 months showed good results. Conclusions: An early diagnosis along with new techniques of radiochemotherapy allow patients to preserve their sphincter function. However, a persistent or recurrent disease needs major operations, which often involve a complex reconstruction. Good team-work and experience in specialized fields give the opportunity to make the best choices to perform critical steps during the management of complex cases

Ten-Step Surgical Approach to Management of Pathology of the Ischiorectal Fossa—A Review of the Literature and Application in a Rare Pelvic Schwannoma

Objective: The ischiorectal fossa is a key anatomical location with boundaries and internal structures owing distinct contributions to function and quality of life. Methods: We highlight the importance of management of pathology in this deep anatomically complex location. Results: We present a ten-step multidisciplinary surgical approach; achieving en bloc radical excision with primary closure and reassuring outcomes. Schwannomas are benign slow-growing nerve sheath tumors. Conclusions: Pelvic schwannomas are rare with only 3 reported cases of the pudendal nerve. We also offer an overview of this rare pathology whilst acknowledging a paucity of recommendations regarding management of disease of the ischiorectal fossa

Handover practice amongst core surgical trainees at the Oxford School of Surgery

Purpose: To date there are no United Kingdom (UK) studies specifically evaluating handovers amongst core surgical trainees (CSTs). The Oxford School of Surgery examined regional handover practice, aiming to assess and improve trainee perception of handover, its quality, and ultimately patient care. Methods: Based on two guidance documents ('Safe handover, safe patients' by the British Medical Association and 'Safe Surgical Practice' by the Royal College of Surgeons'), a 5-point Likert style questionnaire was designed, exploring handover practice, educational value, and satisfaction. This was given to 50 CSTs in 2010. Results: There were responses from 40 CSTs (80.0 %). The most striking findings revolved around perceived educational value, formal training, and auditing practice with regards to handover, which were all remarkably lower than expected. CST handover was thus targeted in the Department of Plastic Surgery at the University Hospital, with the suggestion and implementation of targeted changes to improve practice. Conclusion: In the EWTD era with many missed educational opportunities, daily handover represents an underused educational tool for CSTs, especially in light of competency-based and time-limited training. We recommend modifications based on our results and the literature and hope schools of surgery follow suit nationally by assessing and addressing handover practice

Comorbidity, characteristics, and survival of gastric cancer patients at a VA medical center

e14727 Background: This is to study whether comorbidity indices predict survival in gastric cancer patients (pts). Methods: In an IRB approved protocol, we reviewed the records of pts diagnosed with gastric cancer at a VA Medical Center from 3/1/2000 to 3/31/2011. Comorbidity was assessed with four comorbidity indices, the Charlson Comorbidity Index (CMI), the Kaplan-Feinstein Index (KFI), the Cumulative Illness Rating Scale (CIRS), and VA Comorbidity Scale (VACS). Demographics, stage, histology, grade, weight (wt) loss, hemoglobin (HGB), ALB, Total bilirubin (TBili), creatinine at diagnosis, alcohol or tobacco use, past gastric surgery (pSx), and surgical resection (Sx) were also reviewed. COX survival analysis was performed. Results: There were 49 patients. All were men. 23 (46.9%) pts were Caucasian, 25 (51%) African American and 1 (2%) Hispanic. The median (M) age at diagnosis was 70 years (range 43-90). Median survival was 321 days (4-4221). 17 (35.5%) pts has localized disease (stage I/II), and 31 (64.5 %) advanced disease (stage III/IV). 2 (4%) pts had grade1, 12 (26%) grade 2, 32 (68%) grade 3, and 1 (2.1%) grade 4. M HGB was 12.1 g/dl (range 5.5-16.9), MCV 85.4 fl (59-104), albumin 3.6 g/dl (1.8-4.6), TBili 0.5 mg/dl (0.2-5.1) and creatinine 1 mg/dl (0.7-1.6). M CMI 4.7 (1.1-10.8), CIRS15 5 (0-12), CIRS16 9 (0-19), CIRS17 1.6 (0-2.5), CIRS18 0 ( 0-4), CIRS19 0 (0-1), KFI 3 (0-3), VACS 4 (0-12) Demographic features included alcohol use (51%), M tobacco use 25 PPY (0-80), and M wt loss 9% (0-25) and pSX 5 (10%). 22 pts (47%) has Sx. In univariate survival analysis, only wt loss (p<0.013), stage (p<0.001), grade (p<0.001), Tbil (p<0.003), and Sx (p<0.003) were significant in predicting survival. In multivariate survival analyses, none were significant for predicting survival. Conclusions: Comorbidity did not contribute to the survival of gastric ca pts in this population. More research in a larger sample is needed. Supported by the New Jersey Commission for Cancer Research