Thermal conditions experienced during differentiation affect metabolic and contractile phenotypes of mouse myotubes.

Central pathways regulate metabolic responses to cold in endotherms to maintain relatively stable internal core body temperatures. However, peripheral muscles routinely experience temperatures lower than core body temperature, so that it would be advantageous for peripheral tissues to respond to temperature changes independently from core body temperature regulation. Early developmental conditions can influence offspring phenotypes, and here we tested whether developing muscle can compensate locally for the effects of cold exposure independently from central regulation. Muscle myotubes originate from undifferentiated myoblasts that are laid down during embryogenesis. We show that in a murine myoblast cell line (C2C12), cold exposure (32°C) increased myoblast metabolic flux compared with 37°C control conditions. Importantly, myotubes that differentiated at 32°C compensated for the thermodynamic effects of low temperature by increasing metabolic rates, ATP production, and glycolytic flux. Myotube responses were also modulated by the temperatures experienced by "parent" myoblasts. Myotubes that differentiated under cold exposure increased activity of the AMP-stimulated protein kinase (AMPK), which may mediate metabolic changes in response cold exposure. Moreover, cold exposure shifted myosin heavy chains from slow to fast, presumably to overcome slower contractile speeds resulting from low temperatures. Adjusting thermal sensitivities locally in peripheral tissues complements central thermoregulation and permits animals to maintain function in cold environments. Muscle also plays a major metabolic role in adults, so that developmental responses to cold are likely to influence energy expenditure later in life.

Optimal surgical intervention for achalasia: laparoscopic or robotic approach.

Laparoscopic esophageal myotomy is the standard surgical intervention for achalasia. Compared to standard laparoscopic techniques, use of the robot has theoretical advantages of improved visualization and dexterity. We evaluated the University of Arizona's experience with the two alternatives to compare outcomes. Patients who underwent either laparoscopic or robot-assisted myotomy were identified from a retrospective database from 1/1/2006 to 12/31/2015. Patient demographics, prior treatment, intra-operative complications, operative time, post-operative length of stay and complications, and long-term results were compared between the two groups. We identified 35 laparoscopic and 37 robot-assisted Heller myotomies performed by multiple surgeons. Patient demographics were similar between the two groups with no statistical difference in age, gender, previous operations, pre-operative Botox or dilation treatment, or pre-op Eckardt score. In univariate analysis, the patients with the robotic procedure received a longer myotomy (5.85 cm vs. 5.56 cm for esophageal and 2.92 cm vs. 2.68 cm for gastric) and had a lower post-operative Eckardt score (0.51 vs. 1.09). A trend toward lower incidence of recurrent achalasia symptoms was found in the robotic group (0 patient vs. 4 patients) compared with those who had laparoscopic surgery (p < 0.05). Multivariate analysis showed that a longer gastric myotomy was associated with a lower recurrence rate (p = 0.0002). Both laparoscopic and robot-assisted Heller myotomy can provide definitive treatment of achalasia with good results and few complications. The mechanical advantage provided by the robotic approach may improve outcomes by providing a more complete myotomy and durable long-term result.

National survey of non-small cell lung cancer in the United States: epidemiology, pathology and patterns of care.

PURPOSE: To determine the epidemiology, pathology and patterns of care for patients with non-small cell lung cancer (NSCLC) in the United States. METHODS: In 2001 the National Cancer Data Base, under direction of the American College of Surgeons, conducted a patient care evaluation study in 719 hospitals. We collected information on patient demographics and histories, diagnostic and staging methods, pathology, and initial treatment. RESULTS: Information on 40,909 patients was obtained; 93% were smokers. Slightly more than half were older than 70 years; 58.5% were male and 35% had adenocarcinoma. Comorbid conditions were present in 71.8% and 22% had a prior malignancy. A chest CT scan was performed in 92% of patients and PET scans in 19.3%. Mediastinoscopy was performed in 20.3%. 67.2% of patients had Stage III or IV disease. More of the Hispanic, Asian or Black patients than White had Stage IV disease (p<0.01). Treatment was multimodality in a little over 30% of patients. Surgery alone was primarily utilized for patients in Stage I or II. Choice of treatment correlated more with stage and age than comorbidities. CONCLUSION: Our results substantiated the pattern of increasing proportions of women with NSCLC and the increasing frequency of adenocarcinoma. Most patients presented with Stage III or IV disease. Ethnic minorities were more likely to present in late stage disease than Whites. Treatment strategies depended more on stage and age than comorbid burden. Older patients were less likely to receive surgery and more likely to be treated with radiation only or have no treatment.

Changes in Tracheostomy- and Intubation-Related Tracheal Stenosis: Implications for Surgery.

BACKGROUND: This study sought to identify the changing characteristic patterns and locations of stenosis after tracheostomy or intubation and to assess the risk factors associated with perioperative complication and restenosis after primary resection and reconstruction. METHODS: A retrospective review was performed (January /2012 to March 2015) on patients treated at the University of Arizona Medical Center (Tucson, Arizona) who had symptomatic tracheal stenosis secondary to prolonged intubation or tracheostomy. Data on demographics, surgical approach, and outcome were obtained. Analysis was performed using the χ2 test, Kaplan-Meier estimate of survival, Cox proportional hazards survival analysis, and univariate and multivariate logistic regression. RESULTS: Forty-eight patients were referred for surgical resection, and 36 patients underwent primary resection and reconstruction; 72% of patients had previous endobronchial treatments for stenosis. Fourteen patients had postintubation tracheal stenosis, and 22 had tracheostomy-related stenosis (16 percutaneous, 6 open tracheostomy). Among all patients, 52.8% had stenosis proximal to or involving the cricoid; 72.7% of patients with tracheostomy-related stenosis had stenosis at or proximal to the cricoid, whereas only 21.4% of the patients with intubation-related stenosis had a similar location. Nineteen patients underwent laryngotracheal resection, and 17 patients had tracheal resection. The mean length of resection was 3.6 cm. A body mass index greater than 35 was associated with increased perioperative complications (p = 0.012). In multivariate analysis, patients younger than 30 years of age at operation had an increased relative risk of recurrence. CONCLUSIONS: Recent advances in percutaneous tracheostomy have increased the numbers of patients presenting with proximal tracheal stenosis, thus necessitating more complex subglottic resection and reconstruction. The anastomotic and overall complication rate remains low despite these more complex operations.

Positron emission tomography in well differentiated fetal adenocarcinoma of the lung.

A 47-year-old woman with a 20 pack-year history of cigarette smoking presented with a chest x-ray demonstrating a left upper lobe lung density. Computed tomography of the chest showed a 3-cm lobulated mass in the apical left upper lobe. The lesion demonstrated intense focal uptake on FDG-PET scanning. The patient underwent left upper lobectomy. Pathology demonstrated the histologic and immunohistochemical findings of a well differentiated fetal adenocarcinoma (WDFA). The intense FDG-PET uptake and abundant glycogen stores associated with WDFA may be the result of its embryonic derivation and differential expression of glucose transporter proteins.

Changes in Thoracic Surgery Experience During General Surgery Residency: A Review of the Case Logs From the Accreditation Council for Graduate Medical Education.

BACKGROUND: Although exposure to thoracic surgery is mandated in general surgery residency, little is known about the mix of cases that residents use to meet this requirement and how this has changed over time. We report the experience of general thoracic surgery among general surgery residents using the Accreditation Council for Graduate Medical Education (ACGME) database. METHODS: We performed a retrospective review of the prospectively maintained ACGME resident case log database from 2003 to 2013. Thoracic cases were categorized by procedure type, year, and level of resident participation. A linear regression model was used to determine if there was a significant trend in case volumes over time. RESULTS: First assist volumes decreased in the 90th (-1.46 cases/year, p = 0.0012), 70th (-0.77 cases/year, p = 0.0005), 50th (-0.46 cases/year, p = 0.0013), and 30th percentiles (-0.16 cases/year, p = 0.0187). Pneumonectomy volumes decreased for surgeons junior (-0.01 cases/year, p = 0.0013) and chief residents (-0.01 cases/year, p = 0.005), as did open lobectomy (surgeon junior, -0.202 cases/year, p < 0.0001; chief, -0.08 cases/year, p ≤ 0.0013). Video-assisted (VATS) lobectomy increased for the surgeons junior (0.22 cases/year, p < 0.0001) and chief residents (0.045 cases/year, p < 0.0001). Surgeons junior also had increased volumes of VATS exploratory thoracoscopy (0.11 cases/year, p = 0.0003) and VATS pleurodeisis (0.13 cases/year, p < 0.0001). CONCLUSIONS: Whereas total thoracic volumes on the whole have not changed significantly, resident participation as a first assistant and in key thoracic cases has decreased over the last 11 years, while participation in VATS and minor cases has increased.

Factors in the Selection and Management of Chest Tubes After Pulmonary Lobectomy: Results of a National Survey of Thoracic Surgeons.

BACKGROUND: This study determined patterns of chest tube (CT) selection and management after open lobectomy and minimally invasive lobectomy by thoracic surgeons. METHODS: Surveys were sent electronically to 5,175 thoracic surgeons, and 475 were completed. Responses, blinded so individuals could not be identified, were analyzed and compared according to surgeon characteristics (academic/private practice, years in practice, lobectomy volume, and geographic region). All indicated differences were statistically significant (p < 0.05 by χ(2) tests). RESULTS: CT selection: Most surgeons prefer rigid tubes, and the size most commonly used was 28F. Most place 2 CTs after open lobectomy and 1 CT after minimally invasive lobectomy. Academic surgeons are more likely than private surgeons to use 1 tube after open lobectomy, but both prefer 1 tube after minimally invasive lobectomy. Younger surgeons and high-volume surgeons are more likely to use 1 CT than senior surgeons and low-volume surgeons after both open lobectomy and minimally invasive lobectomy. CT management: Academic and younger surgeons remove the CT sooner after open lobectomy. Younger and high-volume surgeons remove the CT with greater drainage amounts. All groups remove CTs sooner after minimally invasive lobectomy than after open lobectomy. Approximately half of surgeons get a daily chest roentgenogram. Younger and low-volume surgeons are most likely to discharge patients with Heimlich valves, although overall use was in less than 5% (49 of 475) of respondents. Most surgeons believe clinical experience rather than training or the literature determined their CT strategy. CONCLUSIONS: This survey determined the difference in CT management among various groups of surgeons. Clinical experience was the most important factor in determining their CT strategy.

The influence of pulmonary staple line reinforcement on air leaks.

OBJECTIVES: Although uncommon, prolonged postoperative air leaks are a troublesome complication of lung surgery. This study was performed to determine if buttressing pulmonary staple lines would reduce air leakage at varying airway pressures, and if there was a difference between buttressing materials. METHODS: Using cadaver lungs, the development of air leak from staple lines was evaluated at incremental airway pressures. Unreinforced staples were compared to staples reinforced with bovine pericardium and staples reinforced with expanded polytetrafluorethylene (ePTFE). RESULTS: Unreinforced staple lines began to leak air at an airway pressure of 20 mm Hg, and > 90% leaked at a pressure of 35 mm Hg. Both bovine pericardium and ePTFE significantly reduced the incidence of air leak at these airway pressures. At higher airway pressures, ePTFE was superior to bovine pericardium. CONCLUSION: Staple line reinforcement with either material protects against air leak. Patients at risk for elevated airway pressures and/or postoperative ventilator support should be considered for utilization of these staple reinforcing materials.

Video-assisted thoracic surgery sympathectomy for hyperhidrosis.

HYPOTHESIS: Video-assisted thoracic surgery sympathectomy is efficacious for patients with hyperhidrosis. DESIGN: An experience with patients undergoing bilateral video-assisted thoracic surgery sympathectomy was reviewed to evaluate the operative technique and to determine morbidity and outcomes. SETTING: Academic health center. PATIENTS: The cohort included 31 patients (22 women and 9 men). All but 2 patients were of Asian descent, and the average age was 24.9 years. All patients had palmar hyperhidrosis. Two patients also had craniofacial hyperhidrosis, and another 2 had pedal hyperhidrosis. INTERVENTIONS: Bilateral video-assisted thoracic surgery sympathectomy with resection of the second and third ganglia was performed in all patients. Small chest tubes were removed on the first postoperative day. In 30 patients, the procedures were simultaneous; and in 1, it was staged to accommodate lumbar sympathectomy for pedal disease. RESULTS: Perioperatively, no patients died. The only hospital complication was an intraoperative injury to an intercostal artery that required conversion to an open thoracotomy. The average hospital length of stay was 1.2 days (range, 1-3 days). No patient developed Horner syndrome. Long-term follow-up was 2.6 years (range, 3 months to 7 years). Both hands in all patients were warm and dry at the last follow-up, as were the face and scalp in the 2 with craniofacial hyperhidrosis. Ten patients (32%) experienced compensatory sweating, which improved within 6 months. CONCLUSIONS: In this experience, palmar hyperhidrosis is predominantly a disease of young Asian women. Simultaneous bilateral video-assisted thoracic surgery sympathectomy is effective and can be accomplished with minimal morbidity and a short hospitalization. Compensatory sweating occurs in a third of patients, but is generally self-limiting.

Sentinel node biopsy for staging lung cancer.

The importance and value of accurate clinical and pathological staging of lung cancer is emphasized. The philosophy, techniques, and general results of the sentinel node technique for lymphatic mapping are reviewed. The experience with this technique in patients with non-small cell lung cancer is discussed and the future use of lymphatic mapping is pondered.

Safety-net burden hospitals and likelihood of curative-intent surgery for non-small cell lung cancer.

BACKGROUND: Black patients are less likely to undergo surgery for early-stage non-small cell lung cancer (NSCLC) compared with white patients, and are more likely to undergo resection at low-volume hospitals. However, little is known about the relationship between hospital safety-net burden and the likelihood of curative-intent surgery for black and white patients. This study analyzes whether hospital safety-net burden is associated with curative-intent surgery among adult early-stage NSCLC patients treated at facilities accredited by the American College of Surgeons Commission on Cancer. STUDY DESIGN: Adult patients diagnosed with invasive initial primary early-stage (TNM I-II) NSCLC during 2003-2005 were obtained from the National Cancer Data Base. Curative-intent surgery included anatomic resection, wedge resection, and segmentectomy. Hospital safety-net burden was defined as the percent of cancer patients per facility that were Medicaid-insured or uninsured. Generalized estimating equations and linear mixed models were used to control for clustering by facility. RESULTS: Of 52,853 evaluable patients, those treated at high safety-net burden facilities were significantly less likely (unadjusted p < 0.0001) to undergo curative-intent surgery than patients treated at low safety-net burden facilities. Controlling for patient and other facility characteristics, high safety-net burden remained significantly associated (p < 0.0001) with reduced likelihood of curative-intent surgery overall (odds ratio = 0.69; 95% CI, 0.62-0.77) and in black- and white-only models (odds ratio = 0.59, 95% CI, 0.48-0.73; odds ratio = 0.71; 95% CI, 0.63-0.80, respectively). CONCLUSIONS: Both black and white adult patients treated for early-stage NSCLC at high safety-net burden facilities are less likely to undergo curative-intent surgery than those treated at low safety-net burden facilities. Innovative solutions are needed to ensure quality cancer care at high safety-net burden facilities.

Surgical practice: evidence or anecdote.

OBJECTIVES: Our objective is to highlight a few surgical practices that are not based on evidence but are still taught in surgical education, and to assess our experience with these practices. DESIGN: We identified 3 practices (clamping of nasogastric tubes before removal, bowel preparation before elective colon resection, and elective sigmoid colectomy following 2 bouts of diverticulitis), identified the data supporting each practice, and administered a survey to faculty and residents at our institution. SETTING: Wright State University Department of Surgery, Boonshoft School of Medicine, Dayton, Ohio. PARTICIPANTS: Twenty-one faculty and 35 residents responded to the survey. RESULTS: No studies were found relating to clamping nasogastric tubes before removal. Seven faculty (33%) and 11 residents (31%) used this practice. Two faculty (10%) and 0 residents felt this was an evidence-based practice. Faculty were more likely to have reviewed the evidence (85% vs 40%, p < 0.001). Level 2 evidence has shown bowel preparation did not improve outcomes relating to anastomotic leak, wound infection, or septic complications in elective colon resection. Twenty faculty (95%) and 34 residents (97%) used this practice. Faculty were more likely to believe this to be evidence-based (85% vs 49%, p = 0.01). There has been no level 1 or 2 evidence showing that sigmoid colectomy following 2 bouts of diverticulitis improves morbidity or mortality. Fourteen faculty (70%) and 26 residents (76%) reported using this practice. Twelve faculty (60%) and 21 residents (60%) felt this was evidence-based. CONCLUSIONS: Frequent use of surgical practices without evidence support can create a misperception that such practices are evidence-based. Faculty are more likely to change a practice after obtaining continuing medical education, suggesting that residents may need validation by faculty practice of evidence-based procedures before incorporation into their clinical care.

Choice of first intervention is related to outcomes in the management of empyema.

BACKGROUND: The study determined whether the first procedure; simple drainage (tube thoracostomy, pigtail catheter) or operation (video-assisted thoracic surgery [VATS], thoracotomy) was related to outcomes in the management of empyema. METHODS: Data were collected from 104 consecutive patients with empyema. Primary outcomes were additional procedures and death. Predictor variables included age, delay, Karnofsky performance status (KPS), Charlson comorbidity index (CCI), serum albumin, malignancy, Acute Physiology and Chronic Health Evaluation II score, loculations on computed tomography scan, empyema stage, and first procedure choice. RESULTS: Advanced empyema (> or = stage IIA) was present in 84% of patients. Overall treatment success rates (no death, no additional drainage procedures) among evaluable patients for pigtail drainage, tube thoracostomy, VATS, and thoracotomy were 40% (4 of 10), 38% (14 of 37), 81% (13 of 16), and 89% (32 of 36), respectively. Five patients underwent miscellaneous procedures. Univariate variables associated with hospital death included KPS, CCI, and drainage as the first procedure. In multivariate analyses, KPS (coefficient, -0.06, p = 0.002) and failure of the first procedure (odds ratio [OR], 6.76; 95% confidence interval [CI], 1.45 to 31.4, p = .01) were independent predictors of death. Simple drainage as the first procedure was a strong, independent predictor of failure of the first procedure (OR, 11.1; 95% CI, 3.51 to 34.9; p = .00004). CONCLUSIONS: The choice of the first procedure is critical in the outcome for treatment of empyema, even with adjustment for confounding variables. VATS or thoracotomy as initial therapy for advanced empyema is associated with better outcomes.

Effect of the 30-hour work limit on resident experience and education.

PURPOSE: To evaluate the effect of the 30-hour restriction on resident operative participation and assess whether the 30-hour restriction can be extended in certain cases to enhance educational experience and continuity of care without being detrimental to the 80-hour limit. METHODS: In September 2006, we administered a 10-item Likert scale survey to 41 general surgery residents to assess their experience with the 30-hour work restriction. We also reviewed the operative reports from the busiest general surgery service in April 2003 and April 2005 to assess surgical participation before and after the 30-hour restriction. RESULTS: Twenty-three (56%) residents reported missed operations each month because of the 30-hour restriction. Thirty-four (83%) reported occasions where participating in an operation would require only an additional 1-4 hours. Thirty-six (88%) residents reported a better educational experience when operating on patients whom they had evaluated and a preference to operate on patients whom they had evaluated. The operative log review revealed that in April 2003, the resident assigned to the service participated in 47 out of 134 (35%) total operations and 11 out of 30 (37%) operations beginning after noon. In April 2005, the resident assigned to the service participated in 49 out of 109 (45%) total operations and 20 out of 45 (44%) of the operations beginning after noon. CONCLUSION: The difference in the amount of operations involving resident participation before and after the 30-hour restriction, including afternoon cases that would be most affected by the work restriction, was minimal. However, we identified occasions when the 30-hour work restriction could be extended to provide continuity of care and a better educational operative experience while maintaining weekly duty hours within the approved limit. Extensions beyond the 30 hours should be limited to providing unique and comprehensive experiences for residents where the additional time or episodes would not cause resident fatigue.