Development and preliminary validation of a new task-based objective procedure-specific assessment of inguinal hernia repair procedural safety

BACKGROUND

Surgical videos coupled with structured assessments enable surgical training programs to provide independent competency evaluations and align with the American Board of Surgery's entrustable professional activities initiative. Existing assessment instruments for minimally invasive inguinal hernia repair (IHR) have limitations with regards to reliability, validity, and usability. A cross-sectional study of six surgeons using a novel objective, procedure-specific, 8-item competency assessment for minimally invasive inguinal hernia repair (IHR-OPSA) was performed to assess inter-rater reliability using a "safe" vs. "unsafe" scoring rubric.

METHODS

The IHR-OPSA was developed by three expert IHR surgeons, field tested with five IHR surgeons, and revised based upon feedback. The final instrument included: (1) incision/port placement; (2) dissection of peritoneal flap (TAPP) or dissection of peritoneal flap (TEP); (3) exposure; (4) reducing the sac; (5) full dissection of the myopectineal orifice; (6) mesh insertion; (7) mesh fixation; and (8) operation flow. The IHR-OPSA was applied by six expert IHR surgeons to 20 IHR surgical videos selected to include a spectrum of hernia procedures (15 laparoscopic, 5 robotic), anatomy (14 indirect, 5 direct, 1 femoral), and Global Case Difficulty (easy, average, hard). Inter-rater reliability was assessed against Gwet's AC2.

RESULTS

The IHR-OPSA inter-rater reliability was good to excellent, ranging from 0.65 to 0.97 across the eight items. Assessments of robotic procedures had higher reliability with near perfect agreement for 7 of 8 items. In general, assessments of easier cases had higher levels of agreement than harder cases.

CONCLUSIONS

A novel 8-item minimally invasive IHR assessment tool was developed and tested for inter-rater reliability using a "safe" vs. "unsafe" rating system with promising results. To promote instrument validity the IHR-OPSA was designed and evaluated within the context of intended use with iterative engagement with experts and testing of constructs against real-world operative videos.

Using video-based assessment (VBA) to document fellow improvement in safely completing the jejunojejunostomy portion of laparoscopic Roux-en-Y gastric bypass (RYGB) surgery

BACKGROUND

Surgical assessment instruments are used for formative and summative trainee evaluations. To characterize the features of existing instruments and a novel 12-item objective, procedure-specific assessment tool for Roux-en-Y Gastric Bypass (RYGB-OPSA), we evaluated the progress of a single surgical fellow over 17 consecutive surgeries.

METHODS

Seventeen consecutive RYGB videos completed between 8/2021 and 1/2022 by an academic hospital surgical fellow were de-identified and assessed by four board-certified bariatric surgeons using Global Operative Assessment of Laparoscopic Skills (GOALS), General Assessment of Surgical Skill (GASS), and RYGB-OPSA which includes the reflection of transverse colon, identification of ligament of Treitz, biliopancreatic and Roux limbs orientation, jejunal division point selection, stapler use, mesentery division, bleeding control, jejunojejunostomy (JJ) anastomotic site selection, apposition of JJ anastomotic site, JJ creation, common enterotomy closure of JJ, and integrity of anastomosis. The GASS measured economy of motion, tissue handling, appreciating operative anatomy, bimanual dexterity, and achievement of hemostasis. RYGB-OPSA and GASS items were scored "poor-unsafe," "acceptable-safe," or "good-safe." Change in performance was measured by linear trendline slope.

RESULTS

Over the course of 17 procedures, significant improvement was demonstrated by three GOALS items, GOALS overall score, GASS bimanual dexterity, and three RYGB-OPSA tasks: JJ creation, jejunal division point selection, and stapler use. Achievement of hemostasis declined but never rated "poor-unsafe." Overall RYGB-OPSA and GOALS trendlines documented significant increase across the 17 procedures.

CONCLUSION

This examination of a bariatric surgery fellow's operative training experience as measured by three surgical assessment instruments demonstrated anticipated improvements in general skills and safe completion of procedure-specific tasks. Effective surgical assessment instruments have enough sensitivity to show improvement to enable meaningful trainee feedback (low-stakes assessments) as well as the ability to determine safe surgical practice to enable promotion to greater autonomous practice.

Global assessment of surgical skills (GASS): validation of a new instrument to measure global technical safety in surgical procedures

BACKGROUND

Broad implementation of the American Board of Surgery's entrustable professional activities initiative will require assessment instruments that are reliable and easy to use. Existing assessment instruments of general laparoscopic surgical skills have limited reliability, efficiency, and validity across the spectrum of formative (low-stakes) and summative (high-stakes) assessments. A novel six-item global assessment of surgical skills (GASS) instrument was developed and evaluated with a focus upon safe versus unsafe surgical practice scoring rubric.

METHODS

The GASS was developed by iterative engagement with expert laparoscopic surgeons and includes six items (economy of motion, tissue handling, appreciating operative anatomy, bimanual dexterity, achievement of hemostasis, overall performance) with a uniform three-point scoring rubric ("poor-unsafe", "adequate-safe", "good-safe"). To test inter-rater reliability, a cross-sectional study of four bariatric surgeons with experience ranging from 4 to 28 years applied the GASS and the global operative assessment of laparoscopic skills (GOALS) to 30 consecutive Roux-en-Y gastric bypass procedure operative videos. Inter-rater reliability was assessed for a simplified dichotomous "safe" versus "unsafe" scoring rubric using Gwet's AC2.

RESULTS

The GASS inter-rater reliability was very high across all six domains (0.88-1.00). The GASS performed comparably to the GOALS inter-rater reliability scores (0.96-1.00). The economy of motion and bimanual dexterity items had the highest percentage of unsafe ratings (9.2% and 5.8%, respectively).

CONCLUSION

The GASS, a novel six-item instrument of general laparoscopic surgical skills, was designed with a simple scoring rubric (poor-safe, adequate-safe, good-safe) to minimize rater burden and focus feedback to trainees and promotion evaluations on safe surgical performance. Initial evaluation of the GASS is promising, demonstrating high inter-rater reliability. Future research will seek to assess the GASS against a broader spectrum of laparoscopic procedures.

The impact of COVID-19 on medium term weight loss and comorbidities in patients undergoing bariatric surgery and its association with psychological wellbeing

BACKGROUND

The COVID-19 epidemic imposed significant stressors on individuals and changed how medical care is delivered. The affect that this stress has placed on the field of bariatric surgery and the associated outcomes is not well established.

METHODS

A retrospective review of a prospectively collected database from a single academic institution was conducted. Weight loss and comorbidity outcomes were compared between a cohort of patients operated on during the pandemic and a matched group operated on prior to COVID-19. GAD-7 and PHQ-9 questionnaires were used to assess for anxiety and depression, respectively.

RESULTS

A total of 329 and 155 patients were enrolled in the pre-pandemic and COVID-19 groups respectively. There were no significant differences in pre-operative BMI (p = 0.437) or comorbidities: Type II DM (p = 0.810), hypertension (p = 0.879), sleep apnea (p = 0.502), and hyperlipidemia (p = 0.227). Post-operatively, weight loss was comparable at all time points out to 1 year. Type II DM resolution rates were higher in the control cohort at 6 months (p = 0.007), but not at 12 months (p = 1.000). There was no statistically significant difference in resolution rates between the control group and the COVID-19 group for the other measured comorbidities. There was no difference in objective measures of anxiety and depression when comparing the two groups (both p > 0.05).

CONCLUSIONS

The COVID-19 pandemic has fundamentally changed how society and medical systems function. Focusing on pre-operative dietary training and screening for inadequately managed psychological comorbidities yielded similar weight loss outcomes notwithstanding the significant societal and individual stressors with which patients were faced.

Small molecule SWELL1 complex induction improves glycemic control and nonalcoholic fatty liver disease in murine Type 2 diabetes

Type 2 diabetes is associated with insulin resistance, impaired pancreatic β-cell insulin secretion, and nonalcoholic fatty liver disease. Tissue-specific SWELL1 ablation impairs insulin signaling in adipose, skeletal muscle, and endothelium, and impairs β-cell insulin secretion and glycemic control. Here, we show that I_Cl,SWELL and SWELL1 protein are reduced in adipose and β-cells in murine and human diabetes. Combining cryo-electron microscopy, molecular docking, medicinal chemistry, and functional studies, we define a structure activity relationship to rationally-design active derivatives of a SWELL1 channel inhibitor (DCPIB/SN-401), that bind the SWELL1 hexameric complex, restore SWELL1 protein, plasma membrane trafficking, signaling, glycemic control and islet insulin secretion via SWELL1-dependent mechanisms. In vivo, SN-401 restores glycemic control, reduces hepatic steatosis/injury, improves insulin-sensitivity and insulin secretion in murine diabetes. These findings demonstrate that SWELL1 channel modulators improve SWELL1-dependent systemic metabolism in Type 2 diabetes, representing a first-in-class therapeutic approach for diabetes and nonalcoholic fatty liver disease.

Type 2 diabetes is associated with insulin resistance, impaired insulin secretion and liver steatosis. Here the authors report a proof-of-concept study for small molecule SWELL1 modulators as a therapeutic approach to treat diabetes and associated liver steatosis by enhancing systemic insulin-sensitivity and insulin secretion in mice.

Outcomes of peroral endoscopic myotomy in patients with achalasia and prior bariatric surgery: A multicenter experience

Peroral endoscopic myotomy (POEM) in patients with achalasia who are status post bariatric surgery may be technically challenging due to postsurgical scarring and altered anatomy. The aim of the study was to assess the efficacy and safety of POEM for achalasia in patients with prior bariatric surgery. A review of prospectively maintained databases at three tertiary referral centers from January 2015 to January 2021 was performed. The primary outcome of interest was clinical success, defined as a post-treatment Eckardt score ≤ 3 or improvement in Eckardt score by ≥ 1 when the baseline score was <3, and improvement of symptoms. Secondary outcomes were adverse event rates and symptom recurrence. Sixteen patients status post Roux-en-Y gastric bypass (n = 14) and sleeve gastrectomy (n = 2) met inclusion criteria. Indications for POEM were achalasia type I (n = 2), type II (n = 9), and type III (n = 5). POEM was performed either by anterior or posterior approach. The pre-POEM mean integrated relaxation pressure was 26.2 ± 7.6 mm Hg. The mean total myotomy length was 10.2 ± 2.7 cm. The mean length of hospitalization was 1.4 ± 0.7 days. Pre- and postprocedure Eckardt scores were 6.1 ± 2.1 and 1.7 ± 1.8, respectively. The overall clinical success rate was 93.8% (15/16) with mean follow-up duration of 15.5 months. One patient had esophageal leak on postprocedure esophagram and managed endoscopically. Dysphagia recurred in two patients, which was successfully managed with pneumatic dilation with or without botulinum toxin injection. POEM appears to be safe and effective in the management of patients with achalasia who have undergone prior bariatric surgery.

A Comparison of the Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Body Mass Composition as Measured by Air Displacement Plethysmography

BACKGROUND

The laparoscopic sleeve gastrectomy (LSG) is now the most commonly performed bariatric surgery in the world. Multiple studies have demonstrated the equivalence between the LSG and Roux-en-Y gastric bypass (RYGB) with regard to weight loss and comorbidity resolution. Few studies have examined the differences in body mass composition change between the two procedures.

METHODS

Sixty-three patients undergoing either LSG or RYGB underwent calculation of total body mass, ideal body mass, lean mass, and fat mass by air displacement plethysmography (BodPod^tm) prior to surgery and at 12 months postoperatively. Calculations of excess body weight, % excess weight loss, change in % fat mass, and change in % lean mass were then performed at each time interval.

RESULTS

Thirty-three patients underwent LSG and 30 patients underwent RYGB. Mean percent excess weight loss in the LSG and RYGB group was 47.2% and 53.4% respectively (p = 0.165, 95% CI - 14.8-2.6). Mean percent change in fat mass for the LSG group and RYGB group was 9.2% and 10.51% respectively (p = 0.249, 95% CI - 0.86-3.2). Mean percent change in lean mass for the LSG group and RYGB group was 9.4% and 10.49% respectively (p = 0.383, 95% CI 2.85-1.13).

CONCLUSION

The LSG and RYGB both impart dramatic meaningful loss in excess body weight. In addition, both the LSG and RYGB impart dramatic reductions in fat mass. However, both procedures induce loss of lean mass and there appears to be no difference between the two procedures in this regard despite their anatomic and physiologic differences.

Peroral Endoscopic Myotomy Is Feasible and Safe in a Gastric Bypass Population

BACKGROUND

Obesity is public health problem of epidemic proportions. Esophageal dysmotility including achalasia is more commonly seen in an obese population. Standard therapy for achalasia can be complicated by hepatomegaly and a post-surgical anatomy in a pre- and post-bariatric population. Peroral endoscopic myotomy (POEM) has not been adequately studied in this population.

METHODS

A retrospective review of a prospectively collected database was completed. Patients who had undergone a Roux-en-y gastric bypass (RYGB) prior to or following a POEM were enrolled. Patient demographics, operative information and post-operative course data was collected.

RESULTS

Six patients underwent POEM prior to or after RYGB. There were no peri-operative complications with an average length of stay of 1.2 days. Five patients experienced a clinical success with excellent symptom resolution. The one failure was in the setting of type III achalasia, but did have objective evidence of lower esophageal sphincter (LES) relaxation post-operatively.

CONCLUSION

POEM in the setting of bariatric surgery is safe and feasible. The potential increase in GERD following POEM is obviated by RYGB anatomy. In an obese individual, a staged POEM prior to or following a RYGB is an appropriate treatment algorithm for obese and achalasia.

Sarcopenia is associated with increased mortality but not complications following resection and reconstruction of sarcoma of the extremities

BACKGROUND AND OBJECTIVES

Evidence regarding the impact of sarcopenia on operative outcomes in patients with sarcoma is lacking. We evaluated the relationship between sarcopenia and postoperative complications or mortality among patients undergoing tumor excision and reconstruction. ​ METHODS: We retrospectively reviewed 145 patients treated with tumor excision and limb reconstruction for sarcoma of the extremities. Sarcopenia was defined as psoas index (PI) < 5.45 cm² /m² for men and <3.85 cm² /m² for women from preoperative axial CT. Regression analyses were used to assess the association between postoperative complications or mortality with PI, age, gender, race, body mass index, tumor histology, grade, depth, location, size, and neoadjuvant/adjuvant therapy.

RESULTS

There were 101 soft tissue tumors and 44 primary bone tumors. Sarcopenia was present in 38 patients (26%). Sarcopenic patients were older (median age: 72 vs 59 years, P = .0010) and had larger tumors (86.5%, >5 cm vs 77.7%, P = .023). Seventy-three patients experienced complications (51%) and 18 patients died within 1 year. Sarcopenia and metastatic disease were associated with increased 12-month mortality (hazard ratio [HR] = 6.68, P < .001; HR: 8.51, P < .001, respectively) but not complications (HR 1.45, P = .155, odds ratio, 1.32, P = .426, respectively).

CONCLUSIONS

Sarcopenia and metastatic disease were independently associated with postoperative mortality but no complications following surgery.

Unstable Lumbar Spine Osteomyelitis Caused by Trans-Foraminal Migration of Laparoscopic Adjustable Gastric Band Connection Tubing: A Case Report

BACKGROUND

Disconnection of the tubing between the port and LAGB is a well-known complication in general surgery and accounts for up to 17% of LAGB complications. Typically, when this complication occurs patients present with abdominal or pelvic complaints. A complication of spinal infection due to trans-foraminal migration has not been previously reported. The aim of this study is to highlight an unusual infection of the thoracolumbar spine due to laparoscopic adjustable gastric band (LAGB) intragastric erosion, and migration into the lumbar spine causing epidural abscesses, discitis, and osteomyelitis. This case underscores the importance of a thorough surgical history, complete imaging, and multi-disciplinary approach in management of complex spine infections.

METHODS

We report a case of LAGB tubing migration into the spinal canal through the left L2/L3 neural foramen resulting in symptomatic epidural abscesses and osteomyelitis.

RESULTS

Although dislodgement and migration of LAGB tubing has been reported previously, this is the first report of trans-foraminal migration and erosion of lumbar vertebrae, causing osteomyelitis of the spine and epidural abscess formation, subsequent instability and neurologic deficit requiring urgent operative intervention.

CONCLUSIONS

Dislodgement and migration of LAGB tubing is a known complication. While it most commonly leads to abdominal and pelvic sequelae, in rare circumstances it may acutely affect the spine. Careful history, imaging, and multidisciplinary approach are paramount for the successful management.Level of Evidence: V.

Experience with Peroral Endoscopic Myotomy for Achalasia and Spastic Esophageal Motility Disorders at a Tertiary U.S. Center

Background/Aims

Peroral endoscopic myotomy (POEM) is a novel procedure for the treatment of achalasia and spastic esophageal disorders. Experience with POEM is limited, but its reported outcomes are excellent. It is deemed safe even for patients with prior interventions.

Methods

This retrospective review included patients who underwent POEM at a tertiary US center. POEM was performed in a multidisciplinary approach by advanced endoscopists and foregut surgeons. Clinical success was defined as a post-POEM Eckardt score ≤3.

Results

A total of 125 patients were included. Median follow-up period was 18 months (interquartile range, 10–22 months). Clinical success was achieved in 92% of patients and persisted at 12 months in 88% of patients. Mucosal barrier failure (MBF) occurred in 7 patients, 2 of whom required surgical intervention. MBF was more common in patients with prior laparoscopic Heller myotomy (19% vs. 3%, p=0.015). MBF requiring surgical intervention occurred early in the learning curve.

Conclusions

POEM is safe and effective in the treatment of achalasia and spastic esophageal disorders even after failed prior interventions.

Surgical management of gastroesophageal reflux disease in the obese patient

BACKGROUND

Gastroesophageal reflux disease (GERD) affects two thirds of the American population. Obesity is also a disease that affects two thirds of the population. The pathophysiology of reflux disease is reasonably understood, however, the degree to which obesity affects this disease remains poorly defined. Therefore the approach to GERD in the obese patient requires special attention and its own algorithm.

METHODS

A literature search was conducted to consolidate the current available literature on GERD and its management in the obese. In addition, the authors reviewed the literature and present expert opinion on controversial topics.

RESULTS

It is well established that GERD is increased in obesity and the pathophysiology is reviewed. Management options for GERD are discussed, with a focus on the obese population. Management strategies including fundoplication and gastric bypass are discussed. In addition, bariatric surgery in the setting of GERD is also reviewed.

CONCLUSIONS

Currently this is an extremely controversial topic and this white paper presents a strong review of the literature to help guide the management of this challenging disease in this population. Expert recommendations are given throughout the paper based upon the current available data.

Abstract 080: mTORC1 as a Novel Regulator of Vascular Endothelial Function in Obese Mice and Humans

Obesity-induced hypertension is associated with vascular endothelial dysfunction. Recently, our laboratory has demonstrated a critical role of the mammalian target of rapamycin complex 1 (mTORC1) signaling pathway in cardiovascular regulation. Here, we tested the hypothesis that dysregulation of mTORC1 signaling is involved in the endothelial dysfunction associated with obesity in mice and humans. We found that diet-induced obese (DIO) mice that display vascular endothelial dysfunction as compared to lean controls have increased mTORC1 signaling in aortic lysates indicated by the elevated (p<0.05) phosphorylated levels of mTOR and its downstream signaling targets S6-kinase and the ribosomal S6 protein measured by Western blot. Increased vascular mTORC1 signaling in DIO mice was associated with increased aortic NOX2 mRNA expression (2.0±0.2 vs. 1.0±0.3AU in lean controls; p<0.05). Isolated abdominal subcutaneous adipose arterioles from non-diabetic obese (BMI ≥30 kg/m 2 ; n=4; age 51±6 yrs; BMI 54±3 kg/m 2 ) humans exhibited a strong trend towards increased phosphorylated S6 protein compared to normal-weight (BMI <30kg/m 2 ; n=3; age 44±15 yrs; BMI 26±1 kg/m 2 ) individuals (5.0±1.9 vs 0.8±0.4AU; p=0.12), suggesting increased vascular mTORC1 signaling in human obesity. Next, we used an adenoviral construct of a constitutively active (CA) S6-kinase (Ad-CAS6K) to enhance mTORC1 signaling. In mouse endothelial cells, Ad-CAS6K increased mRNA expression of oxidative stress (NOX1and NOX2) and inflammatory markers (IL-1β) and decreased endothelial NOS expression (p<0.05). Transfection of aortic rings with the Ad-CAS6K resulted in impairment in acetylcholine-induced relaxation (Max. relaxation: 67± 5 vs. 81 ±3%; p<0.05) without altering the relaxation evoked by sodium nitroprusside (Max. relaxation: 90±1% vs. 90±2%) recapitulating the vascular phenotype in obese mice. Taken together, our data demonstrate a novel role of the mTORC1 signaling pathway in the regulation of vascular endothelial function. Our data also implicate dysregulation of the endothelial mTORC1 signaling pathway in the endothelial dysfunction associated with obesity.

Laparoscopic Heller myotomy as the gold standard for treatment of achalasia

INTRODUCTION

The recent introductions of novel methods for the treatment of achalasia as well as ongoing controversies about the merits of surgical and endoscopic treatment options have created controversy in identifying the optimal treatment for this condition. This lack of clarity prompted this review of 206 consecutive patients treated with a laparoscopic Heller (LH) myotomy over a 16-year period.

METHODS

A retrospective review of a prospectively collected database was performed of 206 consecutive LH performed by a single surgeon.

RESULTS

In this cohort, 58 % of patients had undergone a prior therapeutic intervention. Over 90 % of patients had relief of dysphagia post-operatively. There was one intraoperative esophageal perforation. There were no mortalities. Only 4/206 patients sustained complications that required either post-op therapeutic intervention or delayed hospital discharge.

CONCLUSION

This paper outlines an operative technique that has yielded outstanding results and may be used as a benchmark against which other therapies can be judged.

Scheduled intravenous acetaminophen reduces postoperative narcotic analgesic demand and requirement after laparoscopic Roux-en-Y gastric bypass

BACKGROUND

Intravenous (i.v.) acetaminophen has the potential to reduce postoperative narcotic analgesic requirement but this has not been reported in bariatric surgery. As lower dosages could reduce undesirable narcotic side effects, we investigated the opioid-sparing effect of concomitant i.v. acetaminophen in bariatric surgery.

METHODS

We performed a retrospective review of our electronic medical records of laparoscopic Roux-en-Y gastric bypasses (LRYGB) performed for severe obesity between 2011 and 2013. We identified 183 patients that received scheduled i.v. acetaminophen in addition to morphine sulfate (MSO4) patient-controlled analgesia (PCA). A cohort of 229 patients from the preceding 2 years who were treated with MSO4 PCA but not acetaminophen was used as a historical control. Patient demographic characteristics and narcotic use data were extracted from electronic medical records. Student's t test or linear regression was used as appropriate (P< .05).

RESULTS

During the first 24-hour postoperative period after LRYGB, narcotic analgesic demand (total PCA demand including nondelivery of narcotic due to lock-out) was reduced by 25% with the concomitant use of i.v. acetaminophen (40.5 versus 30.9 average pushes; P<.05). During the same period, narcotic analgesic dosage requirement was cut down by 20% in the study group (average of 29.9 versus 24.1 mg of MSO4; P<.05). Linear regression analysis confirmed that these changes were independent of age, gender, and body mass index distribution, or type 2 diabetes mellitus.

CONCLUSION

Scheduled i.v. acetaminophen reduces the demand for and the requirement of narcotic analgesia after LRYGB. We provide new evidence in support of the routine use of multimodal analgesia that includes scheduled i.v. acetaminophen in the initial 24-hour period after bariatric surgery.

From Precursors to Pollutants: Some Advances in Combustion Chemistry Diagnostics

The present assessment and prediction of potential pollutant emissions from combustion systems often rely on dedicated combustion models. Their validation depends on the critical examination of the relevant chemical reaction pathways. To this end, a number of combustion diagnostic techniques are available<br />which can probe important chemical constituents in situ, thus providing direct information on the progress of the combustion reactions. Here, some recent experimental advances for the investigation of a suite of targets from molecular intermediates and soot precursors to nascent particles will be presented. Examples include the application of quantum cascade laser absorption spectroscopy (QCLAS), molecular-beam mass<br />spectrometry (MBMS) with different ionization schemes, photoelectron–photoion coincidence (PEPICO) spectroscopy, helium ion microscopy (HIM), and polarization-modulated infrared reflection–absorption spectroscopy (PM-IRRAS).<br /><br />

NF-κB-mediated Pax7 dysregulation in the muscle microenvironment promotes cancer cachexia

Cachexia is a debilitating condition characterized by extreme skeletal muscle wasting that contributes significantly to morbidity and mortality. Efforts to elucidate the underlying mechanisms of muscle loss have predominantly focused on events intrinsic to the myofiber. In contrast, less regard has been given to potential contributory factors outside the fiber within the muscle microenvironment. In tumor-bearing mice and patients with pancreatic cancer, we found that cachexia was associated with a type of muscle damage resulting in activation of both satellite and nonsatellite muscle progenitor cells. These muscle progenitors committed to a myogenic program, but were inhibited from completing differentiation by an event linked with persistent expression of the self-renewing factor Pax7. Overexpression of Pax7 was sufficient to induce atrophy in normal muscle, while under tumor conditions, the reduction of Pax7 or exogenous addition of its downstream target, MyoD, reversed wasting by restoring cell differentiation and fusion with injured fibers. Furthermore, Pax7 was induced by serum factors from cachectic mice and patients, in an NF-κB-dependent manner, both in vitro and in vivo. Together, these results suggest that Pax7 responds to NF-κB by impairing the regenerative capacity of myogenic cells in the muscle microenvironment to drive muscle wasting in cancer.

Specialized instrumentation facilitates stable peritoneal access, gastric decompression, and visualization during transgastric endoscopic peritoneoscopy

PURPOSE

The lack of high-fidelity instrumentation has impeded the development and implementation of natural orifice transluminal endoscopic surgery (NOTES). A steerable flexible trocar (SFT), a rotary access needle (RAN), and an articulating needle knife were developed as components of a flexible instrument set to facilitate transgastric peritoneal access and transluminal abdominal procedures. This cohort study aimed to assess the safety, feasibility, and efficacy of these devices during transgastric peritoneoscopy.

METHODS

Ten morbidly obese patients undergoing laparoscopic Roux-en-Y gastric bypass participated in the study. Following laparoscopic access, transgastric peritoneal access was established using the SFT and RAN, and transgastric peritoneoscopy performed. NOTES adhesiolysis was performed in 2 patients with significant intra-abdominal adhesions due to prior surgery. Outcome measures included time to enter the peritoneal cavity, ability to visualize each quadrant of the abdomen, ability to perform adhesiolysis, and complications.

RESULTS

Ten patients with a median body mass index as stated in table 1 of 47.5 kg/m(2) were enrolled. Successful transgastric access was achieved in 8 of the 10 patients. One procedure was aborted because of difficulty creating the gastrotomy. Another procedure was aborted because of the difficult passage of the device through the oropharynx. An upper esophageal laceration occurred in one patient. Transgastric peritoneal access required 17.4 ± 5.5 minutes, and peritoneoscopy averaged 24.7 ± 7.6 minutes. The 4 abdominal quadrants were visualized and were accessible with the endoscope in all patients.

CONCLUSIONS

The SFT and RAN facilitate transgastric peritoneal access and visualization of difficult-to-reach areas of the peritoneum. These devices provide advanced instrumentation for transgastric NOTES procedures; however, care must be taken during the transoral insertion to avoid complications.

Novel reconstruction of the extrahepatic biliary tree with a biosynthetic absorbable graft

OBJECTIVES

The reference standard technique for the reconstruction of the extrahepatic biliary tree is Roux-en-Y hepaticojejunostomy. This procedure is not without complications and may not be feasible in some patients. This project sought to evaluate a novel approach for repairing common bile duct injuries with a biosynthetic graft. This allows for the reconstruction of the anatomy without necessitating an intestinal bypass.

METHODS

Study subjects were 11 mongrel hounds. Utilizing an open approach, the common bile duct was transected in each animal. A 1-cm graft of a synthetic bioabsorbable prosthesis was interposed over a 5-Fr pancreatic stent and sewn in place as an interposition tube graft with absorbable sutures. Intraoperative cholangiograms and monthly liver function tests were completed. Animals were killed at 6, 7, 8, 10 and 12 months.

RESULTS

The first five animals were killed early in the process of protocol development. One animal developed obstructive symptoms and was killed on postoperative day 14. The next five animals were longterm survivors without evidence of clinically significant graft stenosis. Mean alkaline phosphatase and total bilirubin were normal, at 140 U/l and 0.2 mg/dl, respectively. Histology showed the complete replacement of the graft with native tissue at 6 months.

CONCLUSIONS

  Biliary reconstruction using a synthetic bioabsorbable prosthetic as an interposition tube graft is feasible based on initial results.

An analysis of public posting in reducing speeding behavior on an urban highway

The effects of public posting on speeding behavior on an urban highway were assessed using a reversal design. During baseline the percentage of drivers speeding was measured with a concealed radar unit. During the daily posting condition a highway sign was installed which provided feedback on the percentage of drivers not speeding yesterday and the best record to date. This sign was then covered and reintroduced. Results indicated that the sign was effective in reducing speeding behavior. Furthermore, the effects were most pronounced in reducing the speeds of the faster drivers. Next, daily and weekly postings were compared with the sign alone without numerical feedback: results revealed that the weekly posting condition was as effective as the daily posting condition, but that the sign had no influence when numbers were not posted. Finally, the weekly posting procedure remained effective during a 6-month follow-up condition.

Endoscopic peritoneal access and insufflation: natural orifice transluminal endoscopic surgery

BACKGROUND

Diagnostic transgastric endoscopic peritoneoscopy is a safe model for exploration of the peritoneum. Endoscopic insufflation of the peritoneal cavity has not been validated in humans. We report here our experience with pneumoperitoneum established endoscopically with a laparoscopic insufflator.

DESIGN

Pneumoperitoneum was established with a laparoscopic insufflator through the biopsy channel of the gastroscope. Intra-abdominal pressure was measured with a transfascial Veress needle and compared with endoscopic values. The gastrotomy was used in the creation of the gastric pouch.

PATIENTS

Twenty patients undergoing laparoscopic Roux-en-Y gastric bypass participated in the study. Ten had undergone no previous surgery, whereas the other 10 patients had a history of abdominal procedures.

INTERVENTIONS

Diagnostic transgastric endoscopic peritoneoscopy was performed through a gastrotomy created endoscopically without laparoscopic visualization.

MAIN OUTCOME MEASUREMENTS

Diagnostic findings, operating times, and clinical course were recorded.

RESULTS

The average time for transgastric access was 9.6 minutes. This did not vary in patients with previous surgery (P = .3). Endoscopic insufflation was successful in all patients. The mean endoscopic and laparoscopic pressures were 9.80 and 9.75 mm Hg, respectively (P = .9). In no patients were there limitations to visualization of the abdomen. Adhesions were noted in 80% and 10% of patients with and without a history of surgery, respectively (P = .005). There were no complications related to transgastric passage of the endoscope or exploration of the peritoneal cavity.

CONCLUSIONS

Although limited by the small sample size in this study, we believe that transgastric access may be considered as an alternative approach to peritoneal insufflation and provides a safe alternative for exploration of the abdomen. Endoscopic insufflation through the biopsy channel by using a laparoscopic insufflator seems to be an effective and safe method for establishing pneumoperitoneum.

Diagnostic transgastric endoscopic peritoneoscopy: extension of the initial human trial for staging of pancreatic head masses

BACKGROUND

The validity of natural orifice transluminal endoscopic surgery (NOTES) was confirmed in a human trial of 10 patients undergoing diagnostic transgastric endoscopic peritoneoscopy (DTEP) for staging of pancreatic head masses. This report is an update with 10 additional patients in the series and includes bacterial contamination data.

METHODS

The patients in this human trial were scheduled to undergo diagnostic laparoscopy for abdominal staging of a pancreatic head mass. A second surgeon, blinded to the laparoscopic findings, performed a transgastric endoscopic peritoneoscopy (TEP). The findings of laparoscopic exploration were compared with that those of the TEP. Diagnostic findings, operative times, and clinical course were recorded. Bacterial contamination data were collected for the second cohort of 10 patients. Bacterial samples were collected from the scope before use and the abdominal cavity before and after creation of the gastrotomy. Samples were assessed for bacterial counts and species identification. Definitive care was rendered based on the findings from laparoscopy.

RESULTS

In this study, 20 patients underwent diagnostic laparoscopy followed by DTEP. The average time for completion of diagnostic laparoscopy was 10 min compared with 21 min for TEP. The experience acquired during the initial 10 procedures translated to a 7-min decrease in TEP time for the second 10 cases. For 19 of the 20 patients, DTEP corroborated laparoscopic findings for surgical decision making. One endoscopic and five laparoscopic biopsies were performed. Pancreaticoduodenectomy was performed for 14 patients and palliative gastrojejunostomy for 6 patients. No cross-contamination of the peritoneum or infectious complications were noted. No significant complications related to either the endoscopic or laparoscopic approach occurred.

CONCLUSIONS

This study supports the authors' previous conclusions that the transgastric approach to diagnostic peritoneoscopy is feasible, safe, and accurate. The lack of documented bacterial contamination further supports the use of this technique. Technical issues, including intraabdominal manipulation and gastric closure, require further investigation.

Barbed suture for gastrointestinal closure: a randomized control trial

In an effort to make laparoscopic suturing more efficient, the V-Loc advanced wound closure device (Covidien, Mansfield, MA) has been produced. This device is a self-anchoring barbed suture that obviates the need for knot tying. The goal of this initial feasibility study was to investigate the use of the barbed suture in gastrointestinal enterotomy closure. A randomized study of 12 pigs comparing enterotomy closure with barbed versus a nonbarbed suture of similar tensile strength was performed. To this end, 25 mm enterotomies were made in the stomach (1 control, 1 treatment), jejunum (2 controls, 2 treatments), and descending colon (1 control, 1 treatment). Animals were killed at 3, 7, and 14 days postoperatively (4 each group) and their gastrointestinal tracts harvested; 6 of the 8 enterotomies from each pig underwent burst strength testing. The remaining 2 were fixed in formalin and sent for histological examination. All 12 pigs survived until they were killed without any major complications. Enterotomy closure with barbed suture revealed adhesion scores, burst strength pressures, and histology scores that were similar to those for the control. Jejunal closures resulted in 6 failures at 7 days (3 control, 3 barbed) and 4 failures at 14 days (2 control, 2 barbed). The barbed suture significantly reduced suturing time in the stomach, jejunum, and colon. The V-Loc wound closure device appears to offer comparable gastrointestinal closure to 3-0 Maxon while being significantly faster. Further studies with V-Loc are required to assess its use in laparoscopic surgery.

Formation of the epidermal calcium gradient coincides with key milestones of barrier ontogenesis in the rodent

The epidermal permeability barrier forms late in gestation, coincident with decreased lipid synthesis, increased lipid processing, and development of a mature, multi-layered stratum corneum. Prior studies have shown that changes in the epidermal Ca++ gradient in vivo regulate lamellar body secretion and lipid synthesis, and modulations in extracellular Ca++ in vitro also regulate keratinocyte differentiation. We asked here whether a Ca++ gradient forms in fetal epidermis in utero, and whether its emergence correlates with key developmental milestones of barrier formation and stratum corneum development. Using either ion precipitation or proton induced X-ray emission analysis of fetal mouse and rat skin, we showed that a Ca++ gradient is not present at gestational days 16-18, prior to barrier formation, and that a gradient forms coincident with the emergence of barrier competence (day 19, mouse; day 20, rat) prior to birth. These results are consistent with a role for Ca++ in the regulation of key metabolic events leading to barrier formation. Whether the calcium gradient is formed actively or passively remains to be determined.

Microwave incubation improves lipolytic enzyme preservation for ultrastructural cytochemistry

Standard methods for the ultrastructural detection of lipase and sphingomyelinase activities in the skin result in considerable loss of structural preservation, often interfering with accurate delineation of enzyme localization in association with specific organelles. Moreover, poor preservation occurs, even after extensive aldehyde prefixation, owing to the prolonged incubation times needed to detect residual enzyme activity, which often require non-physiological conditions. A modified incubation protocol is described here, which uses microwave irradiation in conjunction with drastically shortened incubation times, resulting in both superior ultrastructural preservation and excellent localization in mammalian epidermis. This method should be useful generally not only for the study of lipase localization in skin, but also in conjunction with the cytochemical detection of a variety of enzymes in various types of tissue.

Techniques in immuno-electron microscopy. I. Cryosubstitution

Normal skin was cryoprotected by submerging it in a mixture of 30% dimethylformamide (DMF) in PBS or RPMI. Subsequently it was frozen in liquid propane gas. Cryosubstitution was carried out at -90 degrees C by using methanol to which uranyl acetate or osmium tetroxide were added. The tissue was embedded in either Lowicryl K4M at -40 degrees C or in Epon at +60 degrees C. The tissue was evaluated by its overall preservation of ultrastructural details and by its labeling intensity after incubation with either anti-desmoglein or anti-type VII collagen monoclonal antibodies. The mixture of DMF and PBS caused an electron-dense precipitate within the cell. The overall morphology was better in Epon-embedded material than in K4M-embedded material. However, the labeling was best in K4M material. Regardless of whether the tissue was embedded in Epon or K4M, the addition of osmium tetroxide markedly reduced the degree of labeling.

Congenital self-healing reticulohistiocytosis--a benign Langerhans cell disease

An-11-day old girl was seen with brownish nodular lesions scattered over the body with emphasis on the face and scalp. Several lesions had started to involute. Tissue was studied by histopathology, immunohistopathology, routine electron microscopy, and immuno-electron microscopy using cryosubstitution and embedding in K4M. Immunohistopathology revealed that the cells of the dermal infiltrate were Langerhans cells. They expressed Leu 6 and HLA-DR. On routine electron microscopy no Birbeck granules were found in the dermal cells. Birbeck granules in epidermal Langerhans cells were deformed and often situated next to laminated dense bodies. The latter expressed Leu 6 and lysozyme on immuno-electron microscopy. It was concluded that congenital self-healing reticulohistiocytosis is a benign Langerhans cell disease in which Birbeck granules are transformed to laminated dense bodies and possibly degraded by lysosomal enzymes.

Ultrastructural localization of lectin binding sites in human melanocytes

The ultrastructural localization of carbohydrate residues in human melanocytes of normal epidermis and of one compound naevus was studied. The following lectins were used in a post-embedding technique: 1. peanut agglutinin (PNA), which reacts specifically with N-acetylgalactosamine; 2. Concanavalia ensiformis (Con A) indicating alpha-D-glucose and alpha-D-mannose binding sites; 3. Ulex europaeus agglutinin (UEA I) specific for alpha-L-fucose; 4. Wheat germ agglutinin (WGA), reacting specifically with N-acetyl-glucosamine and neuraminic acid (sialic acid); and 5. Limax flavus agglutinin (LFA), also specific for sialic acid (Neu5Ac-alpha-2,3-Gal and Neu5Ac-alpha-2,6-Gal). When incubated with WGA, Con A and LFA strong labelling was seen within the cytoplasm and in the plasma membrane of melanocytes, whereas incubations with PNA and UEA I revealed an occasional gold particle only. The determination of the distribution of carbohydrate residues in normal melanocytes is a prerequisite for future studies of abnormal melanocytes.

Human peripheral blood accessory cell: isolation by hypotonic density gradient, functional, and phenotypical characterization

In order to purify the human peripheral blood-derived accessory cell that cooperate with T lymphocytes in the process of mitogenic stimulation, we developed a new density gradient separation. This was based on the principle of hypotonic swelling of the cells to obtain a differential change of the buoyant densities of cells. By this method, we have obtained a highly accessory cell-depleted lymphocyte fraction whose proliferative response to sodium periodate stimulation was almost aborted. Another fraction containing high accessory cell activity was further divided into Fc-receptor-positive and -negative cells. The latter revealed the highest accessory activity for T lymphocyte periodate stimulation. The cells were characterized according to a number of markers and appeared to resemble lymphoid dendritic cells. Compared with the monocyte/macrophage fraction, they showed veils and dendritiform elongations and expressed reduced values of monocyte/macrophage specific markers. Compared with the high accessory activity of these cells, monocytes/macrophages expressed a low accessory activity.