Alejandro Munoz

Frozen Section Analysis for Intraoperative Margin Assessment During Breast-Conserving Surgery Results in Low Rates of Re-excision and Local Recurrence

BackgroundNegative surgical margins minimize the risk of local recurrence after breast-conserving surgery. Intraoperative frozen section analysis (FSA) is one method for margin evaluation. We retrospectively analyzed records of patients who received breast-conserving therapy with intraoperative FSA of the lumpectomy cavity to assess re-excision rates and local control.MethodsRecords were retrospectively reviewed for individuals who underwent breast-conserving surgery for ductal carcinoma in situ (DCIS) or invasive carcinoma between 1993 and 2003. Inclusion criteria were a minimum of 2 years follow-up and intact tumor at the time of operation. The major outcome measure was local recurrence. The Kaplan-Meier test was used to evaluate local recurrence rates between groups.Results290 subjects with an average age of 57.2 years (range 27–89) underwent 292 lumpectomies with FSA. 11.3% had DCIS, 73.3% had infiltrating ductal, 5.8% had infiltrating lobular, and 9.6% exhibited other forms of invasive carcinoma. 70 subjects underwent additional resection at the time of breast surgery, 16 underwent subsequent re-excision, and 17 underwent subsequent mastectomy. At a median follow-up of 53.4 months (range 5.8–137.8), there were six local recurrences (2.74%) in patients who had breast-conserving procedures and two local recurrences in patients who underwent mastectomy. There were no statistically significant associations among local recurrence rate, tumor size, nodal status, or overall stage. Local recurrences were higher in patients with DCIS compared with invasive carcinoma, and tumors >2cm.ConclusionsIntraoperative FSA allows resection of suspicious or positive margins at the time of lumpectomy and results in low rates of local recurrence and re-excision. The low local recurrence rate reported here is comparable to those reported with other margin assessment techniques.

The impact of work hour restrictions on surgical resident education.

OBJECTIVE Resident work-hour restrictions were instituted in July 2003 based on ACGME mandates. The American Board of Surgery In-Training Examination (ABSITE), American Board of Surgery Qualifying Examination (ABSQE), and operative volume traditionally have been measures of surgical resident education and competency. The objective of this study was to determine the effect of reduced work hours on resident standardized test scores and operative volume at our institution. DESIGN We reviewed ABSITE scores, ABSQE scores, and operative logs from 1997 to 2005 of all general surgery residents. Linear mixed-effects models were fitted for each component ABSITE score (total, basic science, and clinical management), and they were compared using a chi-squared likelihood ratio. Operative logs of graduating residents were compared before and after the work restrictions and were evaluated for association with ABSITE score. p-values less than 0.05 were considered significant. RESULTS The program was compliant with ACGME mandates within 6 months of institution. ABSITE scores improved significantly after the restriction of work hours in both basic science (p = 0.003) and total score (p = 0.008). Clinical management scores were not affected. The number of major cases recorded by graduating residents did not change. A positive correlation was found between number of cases performed during residency and clinical management ABSITE scores (p = 0.045). ABSQE scores were not impacted by operative volume during residency. CONCLUSIONS ABSITE scores improved significantly after the restriction of resident work hours. Resident operative experience was not affected. An unexpected consequence of work-hour restrictions may be an improvement in surgical resident education.

Preoperative Radiographic Assessment of Hepatic Steatosis with Histologic Correlation

BACKGROUND The adverse impact of hepatic steatosis on perioperative outcomes after liver resection is gaining recognition. But the accuracy of preoperative radiologic assessment of fatty liver disease remains unclear. The objective of this study was to correlate preoperative radiologic estimation with postoperative histologic measurement of steatosis. STUDY DESIGN Patients who underwent partial hepatectomy between 1997 and 2001, with complete preoperative radiographic imaging and postoperative pathologic assessment of steatosis, were retrospectively analyzed. The presence of steatosis was assessed radiographically using noncontrast-enhanced CT (NCCT), contrast-enhanced CT (CCT), or MRI, using standard quantitative radiologic criteria. Repeat histologic analysis was used to quantify the extent of hepatic steatosis. RESULTS One hundred thirty-one patients were studied. The overall sensitivity and specificity for all imaging modalities in detecting pathologically confirmed hepatic steatosis were 56% and 82%, respectively. Sensitivity and specificity for NCCT, CCT, and MRI using standard quantitative criteria were 33% and 100%, 50% and 83%, and 88%, and 63%, respectively. Increasing body mass indices adversely affected the accuracy of NCCT (p=0.002). Preoperative chemotherapy did not notably affect radiologic accuracy. CONCLUSIONS The presence of a fatty-appearing liver on NCCT scans indicates clinically significant steatosis, but steatosis cannot be excluded based on a normal NCCT scan, particularly in obese patients. Conversely, normal MRI helps to exclude hepatic steatosis, but abnormal MRI is not a reliable indicator of fatty change. CCT is not an effective means of identifying steatosis. We conclude that, when used alone, conventional cross-sectional imaging does not consistently permit accurate identification of hepatic steatosis.

Immune regulation and graft survival in kidney transplant recipients are both enhanced by human leukocyte antigen matching.

We hypothesized that donor/recipient sharing of the human leukocyte antigen (HLA) involved in allopeptide presentation to the T regulatory cell increases the incidence of immune regulation, thus contributing to long‐term graft survival. Peripheral blood mononuclear cells (PBMC) were obtained from 40 living related donor (LRD) and 31 cadaver renal transplant recipients. The trans vivo delayed type hypersensitivity (DTH) assay was used to assign patients to regulator, nonregulator, and sensitized categories. In a large cohort (n = 1934 patients), primary graft survival and rejection episodes were analyzed using a log rank test for comparison with the DTH results. The highest incidence of regulated anti‐donor DTH was observed in the LRD HLA‐identical group (6/6; 100%) followed by the LRD HLA 1 haplotype matched group (18/27; 67%). Within the cadaver population, two DR‐matched recipients had a higher frequency of regulated anti‐donor DTH (6/11; 55%) than 1 & 0 DR‐matched recipients (3/18; 17%). In a multivariate model, matching for HLA‐DR alone, or for DR plus DQ was significantly (p = 0.045, p = 0.041) correlated with DTH regulation. The better HLA‐matched groups showed the highest incidence of DTH regulation and, in a larger retrospective analysis, displayed better graft survival and freedom from acute rejection (p < 0.0001). HLA matching, and HLA‐DR matching in particular, correlates with the incidence of immune regulation after kidney transplantation.

Thermal Injury with Contemporary Cast-Application Techniques and Methods to Circumvent Morbidity

BACKGROUND Thermal injuries caused by application of casts continue to occur despite the development of newer cast materials. We studied the risk of these injuries with contemporary methods of immobilization. METHODS Using cylindrical and L-shaped limb models, we recorded the internal and external temperature changes that occurred during cast application. Variables that we assessed included the thickness of the cast or splint, dip-water temperature, limb diameter and shape, cast type (plaster, fiberglass, or composite), padding type, and placement of the curing cast on a pillow. These data were then plotted on known time-versus-temperature graphs to assess the potential for thermal injury. RESULTS The external temperature of the plaster casts was an average (and standard deviation) of 2.7 degrees +/- 1.9 degrees C cooler than the internal temperature. The external temperature of twenty-four-ply casts peaked at an average of 84 +/- 42 seconds prior to the peak in the internal temperature. The average difference between the internal and external temperatures of the thicker (twenty-four-ply) casts (4.9 degrees +/- 1.3 degrees C) was significantly larger than that of the thinner (six and twelve-ply) casts (1.5 degrees +/- 1 degrees C) (p < 0.05). Use of dip water with a temperature of <24 degrees C avoided cast temperatures that can cause thermal injury regardless of the thickness of the plaster cast. A dip-water temperature of 50 degrees C combined with a twenty-four-ply cast thickness consistently yielded temperatures high enough to cause burns. Use of splinting material that was folded back on itself was associated with a significant risk of thermal injury. Likewise, placing a cast on a pillow during curing resulted in temperatures in the area of pillow contact that were high enough to cause thermal damage, as did overwrapping of a curing plaster cast with fiberglass. Attempts to decrease internal temperatures with the application of isopropyl alcohol to the exterior of the cast did not decrease the risk of thermal injury. CONCLUSIONS Excessively thick plaster and a dip-water temperature of >24 degrees C should be avoided. Splints should be cut to a proper length and not folded over. Placing the limb on a pillow during the curing process puts the limb at risk. Overwrapping of plaster in fiberglass should be delayed until the plaster is fully cured and cooled.

Visceral obesity is associated with outcomes of total mesorectal excision for rectal adenocarcinoma

General obesity, measured by the body mass index (BMI), increases the technical difficulty of total mesorectal excision (TME) but does not affect oncologic outcomes. The purpose of this study is to compare visceral and general obesity as predictors of outcomes of TME for rectal adenocarcinoma.

Improved Survival After Heart Transplantation in Patients With Bridge to Transplant in the Recent Era: A 17-year Single-center Experience

BACKGROUND Ventricular assist device (VAD) implantation as a bridge to transplant (BTT) has become an important approach for heart transplant candidates. In this study we document our institutional long-term results and recent improvements in BTT therapy. METHODS We retrospectively studied 531 consecutive heart transplant recipients between January 1990 and August 2007. The cohort was divided into old orthotopic heart transplant (OHT) without device (oOHT; n = 399, January 1990 to July 2003), old BTT (oBTT; n = 41, January 1990 to July 2003), new OHT without device (nOHT; n = 58, August 2003 to August 2007) and new BTT (nBTT; n = 33, August 2003 to August 2007) groups. Demographics and post-transplant outcomes were assessed. RESULTS Post-transplant survival in the nBTT group improved significantly compared with the oBTT group (log-rank test, p = 0.01) and survival in the nOHT group tended to be higher than in the oOHT group (p = 0.19). Survival in the oBTT group was significantly worse than in the oOHT group (p < 0.01). However, there was no difference between the nBTT and nOHT groups. The mean period of BTT support was 113 (range 5 to 524) days in the oBTT group and 148 (range 38 to 503) days in the nBTT group. Multivariate analysis revealed diabetes (p < 0.01) and biventricular support (p = 0.04) as significant independent predictors of post-transplant mortality. CONCLUSIONS Post-transplant survival has improved in recent BTT patients. Indeed, recent outcome for OHT after BTT has become equivalent to that for OHT without VAD. These data suggest that advances in device technology and our institutional multidisciplinary program have improved survival and allow BTT candidates to have an outcome equivalent to that of non-VAD patients in the recent era.

Routine Evaluation of the Distal Colon Remnant Before Hartmann’s Reversal is Not Necessary in Asymptomatic Patients

BackgroundReversal of Hartmann’s is a common surgical procedure. Routine preoperative evaluation of the distal colonic/rectal remnant (DCRR) with contrast and/or endoscopic studies is frequently performed despite lack of evidence to support this practice. We hypothesize that asymptomatic patients can safely undergo Hartmann’s reversal without preoperative DCRR evaluation.MethodsAdult patients undergoing reversal of Hartmann’s at a single institution were retrospectively identified. Operative characteristics and outcomes in patients with and without preoperative DCRR evaluation were compared.ResultsBetween 1993 and 2008, 203 patients underwent reversal of Hartmann’s at a tertiary referral center. Sixty-eight patients (33%) did not undergo preoperative DCRR evaluation and had comparable demographic characteristics, comorbidities, DCRR length, and perioperative outcomes to 135 patients who underwent preoperative contrast and/or endoscopic studies. After evaluation, 125 (93%) patients had normal findings, seven (5%) patients had abnormal studies that did not impact their management, and three (2%) patients underwent additional procedures.ConclusionHartmann’s reversal without previous DCRR evaluation is acceptable in selected asymptomatic patients, without increased risk of complications.