Nima Khavanin

Surgical Duration and Risk of Venous Thromboembolism

IMPORTANCE There is a paucity of data assessing the effect of increased surgical duration on the incidence of venous thromboembolism (VTE). OBJECTIVE To examine the association between surgical duration and the incidence of VTE. DESIGN, SETTINGS, AND PARTICIPANTS Retrospective cohort of 1,432,855 patients undergoing surgery under general anesthesia at 315 US hospitals participating in the American College of Surgeons National Surgical Quality Improvement Program from 2005 to 2011. EXPOSURE Duration of surgery. MAIN OUTCOMES AND MEASURES The rates of deep vein thrombosis (DVT), pulmonary embolism (PE), and VTE within 30 days of the index operation. Surgical duration was standardized across Current Procedural Terminology codes using a z score. Outcomes were compared across quintiles of the z score. Multiple logistic regression models were developed to examine the association while adjusting for patient demographics, clinical characteristics, and comorbidities. RESULTS The overall VTE rate was 0.96% (n = 13,809); the rates of DVT and PE were 0.71% (n = 10,198) and 0.33% (n = 4772), respectively. The association between surgical duration and VTE increased in a stepwise fashion. Compared with a procedure of average duration, patients undergoing the longest procedures experienced a 1.27-fold (95% CI, 1.21-1.34; adjusted risk difference [ARD], 0.23%) increase in the odds of developing a VTE; the shortest procedures demonstrated an odds ratio of 0.86 (95% CI, 0.83-0.88; ARD, -0.12%). The robustness of these results was substantiated with several sensitivity analyses attempting to minimize the effect of outliers, concurrent complications, procedural differences, and unmeasured confounding variables. CONCLUSIONS AND RELEVANCE Among patients undergoing surgery, an increase in surgical duration was directly associated with an increase in the risk for VTE. These findings may help inform preoperative and postoperative decision making related to surgery.

Risk factors for 30-day readmission in patients undergoing ventral hernia repair

BACKGROUND Ventral hernia repair (VHR), an increasingly common procedure, may have a greater impact on health care costs than is currently appreciated. Readmissions have the potential to further increase these costs and negatively impact patient outcomes. New national registry data allows for an in-depth look at the predictors and rates of readmission after VHR. METHODS The American College of Surgeons National Surgical Quality Improvement Program database was queried for all patients who underwent only an incisional or VHR in 2011. Patients who had any concomitant procedure were excluded. Using readmission as the dependent variable, a multivariate logistic regression model was created to identify independent predictors of readmission. RESULTS VHR had a 4.9% 30-day readmission rate in 2011. Deep/incisional (12.6%) and superficial site infections (10.5%) were the most common wound complications seen in readmitted patients (both P < .001), whereas sepsis/septic shock (10.14%; P < .001) was the most common systemic complication. Higher class body mass index is not associated with readmission (P = .320). Smoking and chronic obstructive pulmonary disease function as predictors of readmission independently from their association with complications (odds ratio [OR], 1.3; 95% confidence interval [CI], 1.1-1.6; and OR, 1.6, 95% CI, 1.1-2.3, respectively). Operative factors such as the use of mesh (OR, 1.3; 95% CI, 0.995-1.7) or laparoscopy (OR, 1.2; 95% CI, 0.96-1.6) do not increase likelihood of readmission. CONCLUSION There is room for improvement in VHR readmission rates. Although complications are the main driver of readmission, surgeons must be aware of comorbidities that independently increase the odds of readmission, even when a complication does not occur.

Comparison of Perioperative Outcomes in Outpatient and Inpatient Laparoscopic Hysterectomy

STUDY OBJECTIVE To compare 30-day postoperative outcomes in outpatient and inpatient laparoscopic hysterectomy procedures. DESIGN Retrospective observational study (Canadian Task Force classification II-2). SETTING More than 250 hospitals that participate in the American College of Surgeons National Surgical Quality Improvement Program. PATIENTS Women undergoing laparoscopic hysterectomy between 2006 and 2010. INTERVENTION Of 8846 patients, 3564 underwent treatment as outpatients, as defined by hospital billing. MEASUREMENTS AND MAIN RESULTS Overall morbidity was low in both cohorts; however, significantly fewer 30-day complications were observed in outpatients (4.5%) than inpatients (7.2%) (p < .001). Individual medical and wound complications were also rare and were less common in outpatients whenever a significant difference existed. After adjusting for demographic and operative variables, multivariate regression models found outpatients to be at significantly lower risk for overall perioperative morbidity (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.53-0.78). Outpatients were less likely to experience wound complications (OR, 0.63; 95% CI, 0.46-0.87) and were at lower risk of medical complications (adjusted OR, 0.61; 95% CI, 0.49-0.77) and deep vein thrombosis (adjusted odds ratio, 0.61; 95% CI, 0.47-0.80). Outpatient designation was not a significant predictor for repeat operation (p = .09). CONCLUSIONS Outpatient laparoscopic hysterectomy procedures are not associated with increased risk of 30-day postoperative complications.

An algorithmic approach for selective acellular dermal matrix use in immediate two-stage breast reconstruction: indications and outcomes.

Background: Acellular dermal matrix use has gained widespread acceptance—despite higher material costs—because of its ease of use and potential for enhanced cosmesis. The authors developed a resource-sensitive algorithm for selective acellular dermal matrix use with indications and contraindications based on body mass index, breast size, radiation therapy, flap vascularity, and pectoralis anatomy. Methods: The algorithm incorporates preoperative and intraoperative decision points. Complication rates and aesthetic scores were compared for procedures performed before and after adoption of the algorithm. Multiple logistic regression was used to determine the independent influence of the algorithm on postoperative outcomes. Results: One hundred ninety-three breasts underwent reconstruction before and 179 underwent reconstruction after implementation of the algorithm. Overall complication rates did not differ between the cohorts (22.8 percent versus 20.7 percent; p = 0.138). After adjusting for potential confounders, the algorithm did not significantly affect the incidence of infection, seroma, flap necrosis, explantation, or overall complications (all p > 0.05). Aesthetic scores were not affected (2.75 of 4 versus 3.03 of 4; p = 0.138). Acellular dermal matrix use decreased from 84 percent to 36 percent, resulting in a materials cost savings of

Predictors of 30-day readmission after outpatient thyroidectomy: an analysis of the 2011 NSQIP data set.

270,000 over the study period. Conclusions: This algorithm obviated placement of acellular dermal matrix in an estimated 48 percent of immediate tissue-expander reconstructions. Patients treated after adoption of this algorithm experienced similar complication rates and aesthetic outcomes as those who underwent reconstruction before. The authors’ preliminary outcomes demonstrate that evidence-based measures can be taken to selectively use acellular dermal matrix without a concomitant worsening of patient outcomes. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Synergistic interactions with a high intraoperative expander fill volume increase the risk for mastectomy flap necrosis

PURPOSE With enhancements in patient safety and improvements in anesthesia administration, outpatient thyroidectomy is now frequently undertaken as an outpatient procedure, with several peer-reviewed reports of safe implementation totaling over 4500 procedures since 2006. However, robust statistical analyses of predictors for readmission are lacking. METHODS The 2011 NSQIP data set was queried to identify all patients undergoing thyroidectomy on an outpatient basis. Outcomes of interest included surgical and medical complications, reoperation, mortality, and readmission. Univariate and multivariate analyses were utilized to identify the predictors of these events. RESULTS In total 5121 patients were identified to have undergone an outpatient thyroidectomy in 2011. Overall 30-day morbidity was rare with only 47 patients (0.92%) experiencing any perioperative morbidity. One hundred eleven (2.17%) patients were readmitted within 30 days of the operation. A history of COPD was the only preoperative comorbid medical condition that significantly increased a patients risk for readmission (OR 3.73 95% CI 1.57-8.85, p=0.003). Patients with a surgical complication were more than 7 times as likely to be readmitted (OR 2.08-25.28, p=0.002), and those with a medical complication were over 19 times as likely to be readmitted (OR 7.32-50.78, p<0.001). CONCLUSIONS Readmission after outpatient thyroidectomy is infrequent, and compares well with other outpatient procedures. The main identified risks include preoperative COPD and any of the generic postoperative complications tracked in NSQIP. As procedures continue to transition into outpatient settings and financial penalties associated with readmission become a reality, these findings will serve to optimize outpatient surgery utilization.

The influence of BMI on perioperative morbidity following abdominal hysterectomy

Purpose Prosthetic-based breast reconstruction is performed with increasing frequency in the United States. Major mastectomy skin flap necrosis is a significant complication with outcomes ranging from poor aesthetic appearance to reconstructive failure. The present study aimed to explore the interactions between intraoperative fill and other risk factors on the incidence of flap necrosis in patients undergoing mastectomy with immediate expander/implant-based reconstruction. Methods A retrospective review of 966 consecutive patients (1,409 breasts) who underwent skin or nipple sparing mastectomy with immediate tissue expander reconstruction at a single institution was conducted. Age, body mass index, hypertension, smoking status, premastectomy and postmastectomy radiation, acellular dermal matrix use, and application of the tumescent mastectomy technique were analyzed as potential predictors of flap necrosis both independently and as synergistic variables with high intraoperative fill. The following three measures of interaction were calculated: relative excess risk due to interaction, attributable proportion of risk due to interaction, and synergy index (SI). Results Intraoperative tissue expander fill volume was high (≥66.7% of the maximum volume) in 40.9% (576 of 1,409 breasts) of cases. The unadjusted flap necrosis rate was greater in the high intraoperative fill cohort than in the low fill cohort (10.4% vs. 7.1%, p=0.027). Multivariate logistic regression did not identify high intraoperative fill volume as an independent risk factor for flap necrosis (odds ratio 1.442, 95% confidence interval 0.973-2.137, p=0.068). However, four risk factors were identified that interacted significantly with intraoperative fill volume, namely tumescence, age, hypertension, and obesity. The SI, or the departure from additive risks, was largest for tumescence (SI, 25.3), followed by hypertension (SI, 2.39), obesity (SI, 2.28), and age older than 50 years (SI, 1.17). Conclusion In the postmastectomy, hypovascular milieu, multiple risk factors decreasing flap perfusion interact with high intraoperative fill volume to cross a threshold and synergistically increase the risk of flap necrosis.

A systematic review of single-stage augmentation-mastopexy.

OBJECTIVE The objective of the study was to assess the impact of body mass index (BMI) on 30 day perioperative morbidity following abdominal hysterectomy. STUDY DESIGN The 2006-2010 National Surgical Quality Improvement Program data registry was retrospectively reviewed for patients undergoing abdominal hysterectomy. Logistic regression was used to investigate the relationship between BMI and postoperative complications. RESULTS A total of 9917 patients were captured, of which, 2219 were of an ideal BMI, 2765 were overweight, and 4933 were obese. Complications occurred in 11.3% of the procedures, with obese patients experiencing significantly higher rates of morbidity compared with overweight and nonobese patients (13.2%, 9.7%, and 9.0%, respectively; P < .001). Surgical complications were rare; however, a significant step-wise progression was observed with increasing BMI (P < .001). The rate of reoperations and overall medical complication did not differ among cohorts, although the incidence of deep vein thromboses (DVTs) was notably elevated in obese and overweight patients (P = .032). Adjusted odds ratios (ORs) found both overweight and obese patients to be at a significantly higher risk of surgical complications (OR, 1.6 and 3.0, respectively) and wound infections (OR, 1.7 and 3.0, respectively). Overweight patients were also at higher risk for DVTs (OR, 4.6) and obese patients for overall morbidity (OR, 1.4) and wound disruption (OR, 3.6). CONCLUSION Obese and overweight patients demonstrated an increased risk for periorperative morbidity following abdominal hysterectomies.

Risk factors for mastectomy flap necrosis following immediate tissue expander breast reconstruction

Background: The safety of single-stage augmentation-mastopexy remains controversial given the dual purpose of increasing breast volume and decreasing the skin envelope. Currently, the literature is relatively sparse and heterogeneous. This systematic review considered complication profiles and pooled summary estimates in an attempt to guide surgical decision-making. Methods: Multiple databases were queried for combined augmentation-mastopexy outcomes. Whenever possible, meta-analysis of complication rates was performed. Results: Twenty-three studies met inclusion criteria. Average follow-up varied from 16 to 173 weeks, with a majority under 1 year. The pooled total complication rate was 13.1 percent (95 percent CI, 6.7 to 21.3 percent). The most common individual complication was recurrent ptosis, with an incidence of 5.2 percent (95 percent CI, 3.1 to 7.8 percent), followed by poor scarring (3.7 percent; 95 percent CI, 1.9 to 6.1 percent). The pooled incidences of capsular contracture and tissue-related asymmetry were 3.0 percent (95 percent CI, 1.4 to 5.0 percent) and 2.9 percent (95 percent CI, 1.2 to 5.4 percent), respectively. Infection, hematoma, and seroma were rare, with pooled incidences of less than 2 percent each. Three published studies reported data on patient satisfaction. The reoperation rate obtained from 13 studies was 10.7 percent (95 percent CI, 6.7 to 15.4 percent). Conclusions: This meta-analysis encompassed 4856 cases of simultaneous augmentation-mastopexy. Study heterogeneity was high because of differences in surgical techniques, outcome definitions, and follow-up durations. This review suggests that with careful patient selection, pooled complication and reoperation rates for single-stage augmentation-mastopexy are acceptably low.

Individualized Risk of Surgical Complications: An Application of the Breast Reconstruction Risk Assessment Score

Abstract Tissue expander placement is a mainstay of reconstructive surgery in the post-mastectomy patient. Necrosis of the native breast tissue is one of the most significant concerns in their post-operative care. The goal of this study is to elucidate factors that confer risk of this outcome. Chart review was conducted for a consecutive series of immediate tissue expander reconstructions by the two senior authors. Data was collected for several preoperative and intraoperative variables, as well as the outcome of mastectomy flap necrosis. Of the 1566 breasts that were examined, 135 (8.6%) experienced flap necrosis. The cohorts with and without flap necrosis were well matched. Those with the outcome of interest had significantly higher rates of switching to an autologous method of reconstruction (31.9% vs 6.2%, p < 0.001). Regression analysis revealed smoking status, increased age, tumescent mastectomy technique, and high (>66.67%) intraoperative tissue expander fill to confer increased risk of mastectomy flap necrosis. While smoking and older age are well-supported by the literature, tumescent technique and tissue expander fill are more novel points of discussion, which may serve as proxies for other issues. Awareness of these risk factors and their interplay will aid in clinical judgement and postoperative care of these patients.