Potential Pitfalls of Reporting and Bias in Observational Studies With Propensity Score Analysis Assessing a Surgical Procedure: A Methodological Systematic Review

Effect of Additional Trastuzumab in Neoadjuvant and Adjuvant Treatment for Patients with Resectable HER2-Positive Gastric Cancer

BACKGROUND

Recent studies have reported a beneficial role of trastuzumab in neoadjuvant treatment (NAT) among resectable gastric cancer (GC) patients; however, the effect of adjuvant treatment (AT) combined with trastuzumab is understudied. We performed a retrospective cohort study to compare chemotherapies with or without trastuzumab among human epidermal growth factor receptor 2-positive (HER2 +) locally advanced GC patients in the AT and NAT settings, respectively.

METHODS

We enrolled 208 HER2 + resected GC patients who underwent perioperative/postoperative treatment in 2010-2019 in a single-centered hospital, including 135 AT patients and 73 NAT patients. We used inverse probability of treatment weighting (IPTW) to balance potential confounding factors between the treatment groups, and estimated the treatment effect of trastuzumab. Pathological and survival outcomes were evaluated.

RESULTS

The number of trastuzumab-exposed patients in the AT and NAT cohorts was 31 (23.0%) and 34 (46.6%), respectively. After IPTW adjustment, AT combined with trastuzumab showed a better overall survival (OS) over chemotherapy alone (p = 0.023). In IPTW-adjusted NAT analysis, trastuzumab-exposed patients had an improvement in tumor pathological regression and downstaging, with lower tumor regression grade scores (p = 0.002), ypTNM stages (p < 0.001), ypN stages (p = 0.035), and ypT stages (p < 0.001). Loss of HER2 positivity following trastuzumab treatment was observed in NAT patients; however, we did not observe any significant effect of trastuzumab on OS (p = 0.126).

CONCLUSIONS

Given the improvement in tumor regression and downstaging among NAT patients, and the OS benefit in AT patients, trastuzumab could be considered a promising treatment for locally advanced HER2 + GC patients. In particular, re-evaluation of HER2 status should be considered following NAT combined with trastuzumab.

Laparoscopic versus open rectal resection: a 1:2 propensity score-matched analysis of oncological adequateness, short- and long-term outcomes

BACKGROUND

Laparoscopic resections for rectal cancer are routinely performed in high-volume centres. Despite short-term advantages have been demonstrated, the oncological outcomes are still debated. The aim of this study was to compare the oncological adequateness of the surgical specimen and the long-term outcomes between open (ORR) and laparoscopic (LRR) rectal resections.

METHODS

Patients undergoing laparoscopic or open rectal resections from January 1, 2013, to December 31, 2019, were enrolled. A 1:2 propensity score matching was performed according to age, sex, BMI, ASA score, comorbidities, distance from the anal verge, and clinical T and N stage.

RESULTS

Ninety-eight ORR were matched to 50 LRR. No differences were observed in terms of operative time (224.9 min. vs. 230.7; p = 0.567) and postoperative morbidity (18.6% vs. 20.8%; p = 0.744). LRR group had a significantly earlier soft oral intake (p < 0.001), first bowel movement (p < 0.001), and shorter hospital stay (p < 0.001). Oncological adequateness was achieved in 85 (86.7%) open and 44 (88.0%) laparoscopic resections (p = 0.772). Clearance of the distal (99.0% vs. 100%; p = 0.474) and radial margins (91.8 vs. 90.0%, p = 0.709), and mesorectal integrity (94.9% vs. 98.0%, p = 0.365) were comparable between groups. No differences in local recurrence (6.1% vs.4.0%, p = 0.589), 3-year overall survival (82.9% vs. 91.4%, p = 0.276), and disease-free survival (73.1% vs. 74.3%, p = 0.817) were observed.

CONCLUSIONS

LRR is associated with good postoperative results, safe oncological adequateness of the surgical specimen, and comparable survivals to open surgery.

Propensity score matching in otolaryngologic literature: A systematic review and critical appraisal

BACKGROUND

Propensity score techniques can reduce confounding and bias in observational studies. Such analyses are able to measure and balance pre-determined covariates between treated and untreated groups, leading to results that can approximate those generated by randomized prospective studies when such trials are not feasible. The most commonly used propensity score -based analytic technique is propensity score matching (PSM). Although PSM popularity has continued to increase in medical literature, improper methodology or methodological reporting may lead to biased interpretation of treatment effects or limited scientific reproducibility and generalizability. In this study, we aim to characterize and assess the quality of PSM methodology reporting in high-impact otolaryngologic literature.

METHODS

PubMed and Embase based systematic review of the top 20 journals in otolaryngology, as measured by impact factor from the Journal Citations Reports from 2012 to 2018, for articles using PSM analysis throughout their publication history. Eligible articles were reviewed and assessed for quality and reporting of PSM methodology.

RESULTS

Our search yielded 101 studies, of which 92 were eligible for final analysis and review. The proportion of studies utilizing PSM increased significantly over time (p < 0.001). Nearly all studies (96.7%, n = 89) specified the covariates used to calculate propensity scores. Covariate balance was illustrated in 67.4% (n = 62) of studies, most frequently through p-values. A minority (17.4%, n = 16) of studies were found to be fully reproducible according to previously established criteria.

CONCLUSIONS

While PSM analysis is becoming increasingly prevalent in otolaryngologic literature, the quality of PSM methodology reporting can be improved. We provide potential recommendations for authors regarding optimal reporting for analyses using PSM.

Prognostic significance of lymph node yield in patients with synchronous colorectal carcinomas

BACKGROUND

The National Comprehensive Cancer Network (NCCN) guidelines recommend examination of a minimum of 12 lymph nodes (LNs) for accurate staging of a single case of colorectal cancer. However, the guidelines do not support the examination of LNs in synchronous colorectal carcinoma (SCC). This study aimed to investigate the association between lymph node yield and the prognosis of SCC patients.

METHODS

Synchronous colorectal carcinoma patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database over a 10-year interval (2004 to 2013). Systematic dichotomization for optimal cut-off point identification was performed using X-tile. The baseline for the two LNs groups generated was balanced using the propensity score matching (PSM) method.

RESULTS

A total of 4616 patients met the inclusion criteria. The cut-off number for lymph node retrieved from a single patient was 15 and 12 for the first- and second-time diagnosis of SCC, respectively. Age, T category, N category, tumor grade, tumor site, tumor size, and radiation sequence were not balanced in the two groups. After adjusting the baseline in the two groups, the same results were observed. Age, T category, N category, tumor site had a partial effect on lymph node yield. There might be some biological characteristics of the tumor that influence lymph node yield.

CONCLUSIONS

Retrieval of fewer than 15 LNs at the first time of SCC diagnosis indicates worse SCC prognosis. Because factors such as manner of surgical examination influence SCC prognosis, specimens should be preserved for at least 6 months to enable reevaluation should there be a need. Irb: IRB approval is not required because the SEER data are freely accessible.

Robotic versus open oncological gastric surgery in the elderly: a propensity score-matched analysis

Although there is no agreement on a definition of elderly, commonly an age cutoff of ≥ 65 or 75 years is used. Even if robot-assisted surgery is a validated option for the elderly population, there are no specific indications for its application in the surgical treatment of gastric cancer. The aim of this study is to evaluate the safety and feasibility of robot-assisted gastrectomy and to compare the short and long-term outcomes of robot-assisted (RG) versus open gastrectomy (OG). Patients aged ≥ 70 years old undergoing surgery for gastric cancer at the Department of Surgery of San Donato Hospital in Arezzo, between September 2012 and March 2017 were enrolled. A 1:1 propensity score matching was performed according to the following variables: age, Sex, BMI, ASA score, comorbidity, T stage and type of resection performed. 43 OG were matched to 43 RG. The mean operative time was significantly longer in the RG group (273.8 vs. 193.5 min, p < 0.01). No differences were observed in terms of intraoperative blood loss, an average number of lymph nodes removed, mean hospital stay, morbidity and mortality. OG had higher rate of major complications (6.9 vs. 16.3%, OR 2.592, 95% CI 0.623–10.785, p = 0.313) and a significantly higher postoperative pain (0.95 vs. 1.24, p = 0.042). Overall survival (p = 0.263) and disease-free survival (p = 0.474) were comparable between groups. Robotic-assisted surgery for oncological gastrectomy in elderly patients is safe and effective showing non-inferiority comparing to the open technique in terms of perioperative outcomes and overall 5-year survival.

Incomparability of treatment groups is often blindly ignored in randomised controlled trials - a post hoc analysis of baseline characteristic tables

OBJECTIVES

Randomisation is often believed to lead to baseline comparability of treatment groups in controlled trials. This study aims to challenge this popular belief, which is relevant in expectation- but not necessarily in realisation.

STUDY DESIGN AND SETTING

After presenting an overview of methods for assessing baseline comparability of treatment groups in randomised controlled trials (RCTs), we reviewed RCTs published over 1 year in three high-impact medical journals. We extracted data regarding the methods used to evaluate baseline comparability. To quantify baseline balance, we calculated post hoc standardised mean differences (SMDs) in baseline characteristics reported in these trials.

RESULTS

Amongst 142 RCTs, 120 (84.5%) claimed that baseline comparability was achieved. However, 81 RCTs (57%) did not report how they assessed this balance. The rest (61 RCTs, 43%) used traditional statistical tests, which are deemed inappropriate for balance checking. Our post hoc calculation of SMDs showed that 49 (34.5%) RCTs had at least one baseline variable, which might have been strongly unbalanced (i.e., SMD ≥25%) across treatment groups.

CONCLUSION

Baseline incomparability of treatment groups in RCTs is often blindly ignored. We suggest it be thoroughly evaluated and transparently reported, using the standardised mean difference or other proper balance metrics.

Should simultaneous stoma closure and incisional hernia repair be avoided?

PURPOSE

Patients scheduled for stoma closure may also have an incisional hernia. Studies have reported acceptable outcomes after contaminated ventral hernia repair, but whether stoma closure and incisional hernia repair should be performed as a combined procedure is unknown. This study examined combined stoma closure and incisional hernia repair compared with incisional hernia repair only.

METHODS

This was a nationwide propensity-score matched study. Patients who underwent elective incisional hernia repair from 2007-2017 were identified in the Danish Hernia Database. All patients who underwent concurrent stoma closure were matched 1:3 with patients who underwent incisional hernia repair only. The primary outcome was reoperation for hernia recurrence, whereas secondary outcomes included anastomotic leakage, length of hospital stay, and 30-day reoperation and readmission rates.

RESULTS

In total, 516 patients were included. The risk of reoperation for recurrence was increased after concurrent stoma closure compared with incisional hernia repair only (hazard ratio 1.69, 95% confidence interval 1.01-2.82, p = 0.044). Seven (5.4%) patients who underwent incisional hernia repair concurrent to stoma closure were reoperated for anastomotic leakage. Length of hospital stay and reoperation rates within 30 days were increased after concurrent stoma closure compared with incisional hernia repair only (median 8 versus 3 days, p < 0.001 and 29.5% versus 18.6%, p = 0.013), whereas there was no difference in 30-day readmission rates (p = 0.251).

CONCLUSIONS

Stoma closure and incisional hernia repair should be performed as a dual-stage procedure to decrease the risk of hernia recurrence.

Graduated compression stockings in the prevention of postoperative pulmonary embolism. A propensity-matched retrospective case-control study of 24 273 patients

INTRODUCTION

Recommendations for venous thromboembolism and deep venous thrombosis (DVT) prophylaxis using graduated compression stockings (GCS) is historically based and has been critically examined in current publications. Existing guidelines are inconclusive as to recommend the general use of GCS.Patients/Methods: 24 273 in-patients (general surgery and orthopedic patients) undergoing surgery between 2006 and 2016 were included in a retrospectively analysis from a single center. From January 2006 to January 2011 perioperative GCS was employed additionally to drug prophylaxis and from February 2011 to March 2016 patients received drug prophylaxis alone. According to german guidelines all patients received venous thromboembolism prophylaxis with weight-adapted LMWH. Risk stratification (low risk, moderate risk, high risk) was based on the guideline of the American College of Chest Physicians. Data analysis was performed before and after propensity matching (PM). The defined primary endpoint was the incidence of symptomatic or fatal pulmonary embolism (PE). A secondary endpoint was the incidence of deep venous thromboembolism (DVT).

RESULTS

After risk stratification (low risk n = 16 483; moderate risk n = 4464; high risk n = 3326) a total of 24 273 patient were analyzed. Before to PM the relative risk for the occurrence of a PE or DVT was not increased by abstaining from GCS. After PM two groups of 11 312 patients each, one with and one without GCS application, were formed. When comparing the two groups, the relative risk (RR) for the occurrence of a pulmonary embolism was: Low Risk 0.99 [CI95% 0.998-1.000]; Moderate Risk 0.999 [CI95% 0.95-1.003]; High Risk 0.996 [CI95% 0.992-1.000] (p > 0.05). The incidence of PE in the total group LMWH alone was 0.1% (n = 16). In the total group using LMWH + GCS, the incidence was 0.3% (n = 29). RR after PM was 0.999 [CI95% 0.998-1.00].

CONCLUSION

In comparison to prior studies with only small numbers of patients our trial shows in a large group of patients with moderate and high risk developing VTE we can support the view that abstaining from GCS-use does not increase the incidence of symptomatic or fatal PE and symptomatic DVT.

Big Data in Ophthalmology

Big data is the fuel of mankind's fourth industrial revolution. Coupled with new technology such as artificial intelligence and deep learning, the potential of big data is poised to be harnessed to its maximal in years to come. In ophthalmology, given the data-intensive nature of this specialty, big data will similarly play an important role. Electronic medical records, administrative and health insurance databases, mega national biobanks, crowd source data from mobile applications and social media, and international epidemiology consortia are emerging forms of "big data" in ophthalmology. In this review, we discuss the characteristics of big data, its potential applications in ophthalmology, and the challenges in leveraging and using these data. Importantly, in the next phase of work, it will be pertinent to further translate "big data" findings into real-world applications, to improve quality of eye care, and cost-effectiveness and efficiency of health services in ophthalmology.

A review of the use of propensity score diagnostics in papers published in high-ranking medical journals

Background

Propensity scores are widely used to deal with confounding bias in medical research. An incorrectly specified propensity score model may lead to residual confounding bias; therefore it is essential to use diagnostics to assess propensity scores in a propensity score analysis. The current use of propensity score diagnostics in the medical literature is unknown. The objectives of this study are to (1) assess the use of propensity score diagnostics in medical studies published in high-ranking journals, and (2) assess whether the use of propensity score diagnostics differs between studies (a) in different research areas and (b) using different propensity score methods.

Methods

A PubMed search identified studies published in high-impact journals between Jan 1st 2014 and Dec 31st 2016 using propensity scores to answer an applied medical question. From each study we extracted information regarding how propensity scores were assessed and which propensity score method was used. Research area was defined using the journal categories from the Journal Citations Report.

Results

A total of 894 papers were included in the review. Of these, 187 (20.9%) failed to report whether the propensity score had been assessed. Commonly reported diagnostics were p-values from hypothesis tests (36.6%) and the standardised mean difference (34.6%). Statistical tests provided marginally stronger evidence for a difference in diagnostic use between studies in different research areas (p = 0.033) than studies using different propensity score methods (p = 0.061).

Conclusions

The use of diagnostics in the propensity score medical literature is far from optimal, with different diagnostics preferred in different areas of medicine. The propensity score literature may improve with focused efforts to change practice in areas where suboptimal practice is most common.

Outcomes After Minimally-invasive Versus Open Pancreatoduodenectomy: A Pan-European Propensity Score Matched Study

OBJECTIVE

To assess short-term outcomes after minimally invasive (laparoscopic, robot-assisted, and hybrid) pancreatoduodenectomy (MIPD) versus open pancreatoduodenectomy (OPD) among European centers.

BACKGROUND

Current evidence on MIPD is based on national registries or single expert centers. International, matched studies comparing outcomes for MIPD and OPD are lacking.

METHODS

Retrospective propensity score matched study comparing MIPD in 14 centers (7 countries) performing ≥10 MIPDs annually (2012-2017) versus OPD in 53 German/Dutch surgical registry centers performing ≥10 OPDs annually (2014-2017). Primary outcome was 30-day major morbidity (Clavien-Dindo ≥3).

RESULTS

Of 4220 patients, 729/730 MIPDs (412 laparoscopic, 184 robot-assisted, and 130 hybrid) were matched to 729 OPDs. Median annual case-volume was 19 MIPDs (interquartile range, IQR 13-22), including the first MIPDs performed in 10/14 centers, and 31 OPDs (IQR 21-38). Major morbidity (28% vs 30%, P = 0.526), mortality (4.0% vs 3.3%, P = 0.576), percutaneous drainage (12% vs 12%, P = 0.809), reoperation (11% vs 13%, P = 0.329), and hospital stay (mean 17 vs 17 days, P > 0.99) were comparable between MIPD and OPD. Grade-B/C postoperative pancreatic fistula (POPF) (23% vs 13%, P < 0.001) occurred more frequently after MIPD. Single-row pancreatojejunostomy was associated with POPF in MIPD (odds ratio, OR 2.95, P < 0.001), but not in OPD. Laparoscopic, robot-assisted, and hybrid MIPD had comparable major morbidity (27% vs 27% vs 35%), POPF (24% vs 19% vs 25%), and mortality (2.9% vs 5.2% vs 5.4%), with a fewer conversions in robot-assisted- versus laparoscopic MIPD (5% vs 26%, P < 0.001).

CONCLUSIONS

In the early experience of 14 European centers performing ≥10 MIPDs annually, no differences were found in major morbidity, mortality, and hospital stay between MIPD and OPD. The high rates of POPF and conversion, and the lack of superior outcomes (ie, hospital stay, morbidity) could indicate that more experience and higher annual MIPD volumes are needed.

Gemcitabine-based adjuvant chemotherapy in subtypes of ampullary adenocarcinoma: international propensity score-matched cohort study

BACKGROUND

Whether patients who undergo resection of ampullary adenocarcinoma have a survival benefit from adjuvant chemotherapy is currently unknown. The aim of this study was to compare survival between patients with and without adjuvant chemotherapy after resection of ampullary adenocarcinoma in a propensity score-matched analysis.

METHODS

An international multicentre cohort study was conducted, including patients who underwent pancreatoduodenectomy for ampullary adenocarcinoma between 2006 and 2017, in 13 centres in six countries. Propensity scores were used to match patients who received adjuvant chemotherapy with those who did not, in the entire cohort and in two subgroups (pancreatobiliary/mixed and intestinal subtypes). Survival was assessed using the Kaplan-Meier method and Cox regression analyses.

RESULTS

Overall, 1163 patients underwent pancreatoduodenectomy for ampullary adenocarcinoma. After excluding 187 patients, median survival in the remaining 976 patients was 67 (95 per cent c.i. 56 to 78) months. A total of 520 patients (53·3 per cent) received adjuvant chemotherapy. In a propensity score-matched cohort (194 patients in each group), survival was better among patients who received adjuvant chemotherapy than in those who did not (median survival not reached versus 60 months respectively; P = 0·051). A survival benefit was seen in patients with the pancreatobiliary/mixed subtype; median survival was not reached in patients receiving adjuvant chemotherapy and 32 months in the group without chemotherapy (P = 0·020). Patients with the intestinal subtype did not show any survival benefit from adjuvant chemotherapy.

CONCLUSION

Patients with resected ampullary adenocarcinoma may benefit from gemcitabine-based adjuvant chemotherapy, but this effect may be reserved for those with the pancreatobiliary and/or mixed subtype.

Evaluating a Clinical Pathway in Laparoscopic Cholecystectomy: Effective in Reducing Complications? A Propensity Score Matching Analysis

Background

Care pathways are primarily aimed at decreasing length of hospital stay (LOS) and preventing unnecessary costs while maintaining or improving the quality of care. In laparoscopic cholecystectomy, there is insufficient evidence for proving an impact upon postoperative complications.

Methods

In this retrospective study, logistic regression was used to calculate a propensity score, and, after carrying out 1:1 nearest-neighbor matching, 296 patients were analyzed in both groups with regard to postoperative complications using the Clavien-Dindo classification system as a primary aim. In addition, secondary aims were LOS, compliance to care, and deviation from the care pathway with respect to patient discharge. Relative risk of the primary outcome was calculated and compared with the e-value as sensitivity testing approach.

Results

Due to the mandatory part of the care pathway, patient record compliance was 100%. Deviation from the care pathway with respect to the planned patient discharge on postoperative day 2 was noted in 16% of the cases. After adjustment for potential factors, the relative risk when comparing Clavien-Dindo complication grades 0 versus 1-4 is 1.64 (95% CI 0.87-3.11), which did not reach significance (p = 0.127). After matching, LOS lasted 3.69 days without and 3.26 days with the care pathway, respectively.

Conclusions

Against the background of already implemented structured standard operation procedures, a care pathway is not able to reduce postoperative complications. Nevertheless, we consider our clinical pathway a highly valuable tool for the interdisciplinary management of patient hospitalization under the supervision of experienced specialized surgeons.

The effect of neoadjuvant short-course radiotherapy and delayed surgery versus chemoradiation on postoperative outcomes in locally advanced rectal cancer patients - A propensity score matched nationwide audit-based study

OBJECTIVE

To investigate differences in postoperative outcomes between short-course radiotherapy and delayed surgery (SCRT-delay) and chemoradiation (CRT) in patients with locally advanced rectal cancer (LARC).

BACKGROUND

Previous trials suggest that SCRT-delay could serve as an adequate neoadjuvant treatment for LARC. Therefore, in frail LARC patients SCRT-delay is recommended as an alternative to CRT. However, data on postoperative outcomes after SCRT-delay in comparison to CRT is scarce.

METHODS

This was an observational study with data from the Dutch ColoRectal Audit (DCRA). LARC patients who underwent surgery (2014-2017) after an interval of ≥6 weeks were included. Missing values were replaced by multiple imputation. Propensity score matching (PSM), using age, Charlson Comorbidity Index, cT-stage and surgical procedure, was applied to create comparable groups. Differences in postoperative outcomes were analyzed using Chi-square test for categorical variables, independent sample t-test for continuous variables and Mann-Whitney U test for non-parametric data.

RESULTS

2926 patients were included. In total, 288 patients received SCRT-delay and 2638 patients underwent CRT. Patients in the SCRT-delay group were older and had more comorbidities. Also, ICU-admissions and permanent colostomies were more common, as well as pulmonic, cardiologic, infectious and neurologic complications. After PSM, both groups comprised 246 patients with equivalent age, comorbidities and tumor stage. There were no differences in postoperative complications.

CONCLUSION

Postoperative complications were not increased in LARC patients undergoing SCRT-delay as neoadjuvant treatment. Regarding treatment-related complications, SCRT-delay is a safe alternative neoadjuvant treatment option for frail LARC patients.

What is the outcome of the open IPOM versus sublay technique in the treatment of larger incisional hernias?: A propensity score-matched comparison of 9091 patients from the Herniamed Registry

Introduction

In an Expert Consensus guided by systematic review, the panel agreed that for open elective incisional hernia repair, sublay mesh location is preferred, but open intraperitoneal onlay mesh (IPOM) may be useful in certain settings. This analysis of data from the Herniamed Registry aimed to compare the outcomes of open IPOM and sublay technique.

Methods

Propensity score matching of 9091 patients with elective incisional hernia repair and with defect width ≥ 4 cm was performed. The following matching variables were selected: age, gender, risk factors, ASA score, preoperative pain, defect size, and defect localization.

Results

For the 1977 patients with open IPOM repair and 7114 patients with sublay repair, n = 1938 (98%) pairs were formed. No differences were seen between the two groups with regard to the intraoperative, postoperative and general complications, complication-related reoperations and recurrences. But significant disadvantages were identified for the open IPOM repair in respect of pain on exertion (17.1% vs. 13.7%; p = 0.007), pain at rest (10.4% vs. 8.3%; p = 0.040) and chronic pain requiring treatment (8.8% vs. 5.8%; p < 0.001), in addition to rates of 3.8%, 1.1% and 1.1%, respectively, occurring in both matched patients. No relationship with tacker mesh fixation was identified. There are only very few reports in the literature with comparable findings.

Conclusion

Compared with sublay repair, open IPOM repair appears to pose a higher risk of chronic pain. This finding concords with the Expert Consensus recommending that incisional hernia should preferably be repaired using the sublay technique.

Report of a Quality Improvement Program for Reducing Postoperative Complications by Using a Surgical Risk Calculator in a Cohort of General Surgery Patients

PURPOSE

The study investigates whether postoperative complications in elective surgery can be reduced by using a risk calculator via raising the awareness of the surgeon in a preoperative briefing. Postoperative complications like wound infections or pneumonia result in a high burden for healthcare systems. Multiple quality improvement programs address this problem like the ACS NSQIP Surgical Risk Calculator^® (SRC).

METHODS

To determine whether the preoperative usage of the SRC could reduce inpatient postoperative complications, two groups of 832 patients each were compared using propensity score matching. The SRC was employed retrospectively in the period 2012/2013 in one group ("Retro") and prospectively in the other group ("Prosp") in the period 2014/2015. Actual inpatient postoperative complications were classified by SRC complication categories and compared with the Clavien-Dindo complication classification system (Dindo et al. in Ann Surg 240:205-213, 2004).

RESULTS

Comparing SRC "serious complication" and SRC "any complication," a nonsignificant increase in the "Prosp"-group was apparent (serious complication: 6.6% vs. 8.5%, p = 0.164; any complication: 8.5% vs. 9.7%, p = 0.444).

CONCLUSION

Use of the SRC neither reduces inpatient postoperative complications nor the severity of complications. The calculations of the SRC rely on a 30-day postoperative follow-up. Poor sensitivity and medium specificity of the SRC showed that the SRC could not make accurate predictions in a short follow-up time averaging 6 days. Alternatively, since the observed complication rate was low in our study, in an environment of already highly implemented risk management tools, reductions in complications are not easily achieved.

Comparing large pore lightweight mesh versus small pore heavyweight mesh in open mesh plug repair of primary and recurrent unilateral inguinal hernia - A questionnaire study for a retrospective analysis of a cohort of elective groin hernia patients using propensity score matching

PURPOSE

For surgical treatment of inguinal hernia, large-pore, lightweight mesh has been shown to offer advantages over small-pore, heavyweight options in terms of chronic post-operative inguinal pain, but without the disadvantage of having to deal with an increased recurrence rate. Limited data are available for the mesh plug repair technique. Therefore, the primary aim of this study is to compare large-pore, lightweight mesh versus small-pore, heavyweight mesh for mesh plug repair with regard to chronic pain and recurrences in elective primary unilateral hernias. In addition, we report our experience in repairing recurrent hernias.

METHODS

Using a modified version of the questionnaire from the Danish Hernia Registry, two groups were surveyed: elective primary unilateral hernias and recurrent unilateral hernias. In both groups small-pore, heavyweight mesh (HWM) and lightweight, large-pore mesh (LWM) were compared with respect to chronic pain and recurrences. Propensity score matching (PS) was carried out on a pool of 1,782 patients. Effect sizes were assessed by using Cohen's d and Cramer's V.

RESULTS

If the questionnaire item 'lump/swelling' is considered as a surrogate for recurrence (clinically verified in our study), the results in primary hernias after HWM show a 6.0% recurrence rate and 7.3% after LWM (p = 0.487) with a mean follow up of 31,3 months in HWM and 29,2 months in LWM respectively. The questionnaire item 'pain impacting on work/leisure activities' was answered with Yes in 11.5% following HWM and in 10.5% following LWM (p = 0.665). After the evaluation of the overall surgical results, we did not find differences. Comparing primary and recurrent hernia repair we found below small effect size differences with respect to the items of the questionnaire.

CONCLUSIONS

The use of LWM in repairing elective unilateral primary hernias by the mesh plug technique does not result in less chronic pain and more recurrences when compared with HWM. Recurrent hernias repaired by the mesh plug technique may have same outcomes like in primary hernia repair when considering the magnitude of effect sizes.

Liver Transplantation with "Hors Tour" Allocated Versus Standard MELD Allocated Grafts: Single-Center Audit and Impact on the Liver Pool in France

BACKGROUND

The French transplant governing system defined "Rescue" (the so-called "Hors Tour") livers as those livers which were declined for the five top-listed patients. This study compares the outcomes following liver transplantation (LT) in patients who received a donor liver through a rescue allocation (RA) procedure or according to MELD score priority (standard allocation, SA) and evaluates the impact on the graft pool of a proactive policy to accept RA grafts.

METHODS

Data from all consecutive patients who underwent LT with SA or RA grafts from 2011 to 2015 were compared in terms of short- and long-term outcomes.

RESULTS

The 249 elective first LTs were performed with 64 (25.7%) RA and 185 (74.3%) SA grafts. RA grafts were obtained from older donors and were associated with a longer cold ischemia time. Recipients of RA livers were older and had lower MELD scores. The rates of delayed graft function, primary nonfunction, retransplantation, complications, and mortality were similar between the RA and SA groups. At 1 and 3 and 5 years, graft and patient survival rates were similar between the groups. These results were maintained after matching on recipient characteristics. Our proactive policy to accept RA grafts increased the liver pool for elective first transplantation by 25%.

CONCLUSIONS

RA livers can be safely transplanted into selected recipients and significantly expand the liver pool.

Female sex as independent risk factor for chronic pain following elective incisional hernia repair: registry-based, propensity score-matched comparison

Introduction

To date, little attention has been paid by surgical scientific studies to sex as a potential influence factor on the outcome. Therefore, there is a sex bias in the surgical literature. With an incidence of more than 20% after 3 years, incisional hernias are a common complication following abdominal surgical procedures. The proportion of women affected is around 50%. There are very few references in the literature to the influence of sex on the outcome of elective incisional hernia repair.

Materials and methods

In all, 22,895 patients with elective incisional hernia repair from the Herniamed Registry were included in the study. The patients had undergone elective incisional hernia repair in a laparoscopic IPOM, open sublay, open IPOM, open onlay or suture technique. 1-year follow-up was available for all patients. Propensity score matching was performed for the 11,480 female (50.1%) and 11,415 male (49.9%) patients, creating 8138 pairs (82.0%) within fixed surgical procedures.

Results

For pain on exertion (11.7% vs 18.3%; p < 0.001), pain at rest (7.53% vs 11.1%; p < 0.001), and pain requiring treatment (5.4% vs 9.1%; p < 0.001) highly significant disadvantages were identified for the female sex when comparing the different results within the matched pairs. That was also confirmed on comparing sex within the individual surgical procedures. No sex-specific differences were identified for the postoperative complications, complication-related reoperations or recurrences. Less favorable intraoperative complication results in the female sex were observed only for the onlay technique.

Conclusions

Female sex is an independent risk factor for chronic pain after elective incisional hernia repair.

Short- and Long-term Outcomes after Robotic and Laparoscopic Liver Resection for Malignancies: A Propensity Score-Matched Study

OBJECTIVES

A laparoscopic approach improves short-term outcomes and maintains long-term outcomes compared to an open approach. In turn, the recent development of robotic surgery raises the question whether it performs as well as laparoscopic surgery. The aim of this study was to compare the short- and long-term outcomes of laparoscopic liver resection (LLR) and robotic liver resection (RLR) for malignancies.

METHOD

From 2011 to 2017, the study population included 111 patients in the LLR group and 61 in the RLR group. Short- and long-term outcomes were compared before and after propensity score matching (PSM).

RESULTS

Operative mortality rate was nil. The intraoperative blood transfusion rate was higher during RLR (15% vs. 2%, p = 0.0009). Major morbidity and hospital stay were not different between the two groups. The resection margin width (LLR 7 mm vs. RLR 10 mm, p = 0.13) and R1 resection rates (resection margin width < 1 mm; LLR 15% vs. RLR 11%, p = 0.49) were similar. After PSM (55 patients in each group), the blood transfusion, major morbidity, hospital stay and R1 resection were similar between the two groups. When considering the largest subset of patients with hepatocellular carcinoma including 114 patients (66%), the 3-year overall survival rate was 80% in the LLR group and 97% in the RLR group (p = 0.10) and remained similar after PSM (p = 0.27). The 3-year recurrence-free survival rate was 50% in the LLR group and 64% in the RLR group (p = 0.30) and remained similar after PSM (p = 0.26).

CONCLUSIONS

No differences were found in blood transfusion, incidence of positive resection margins and long-term outcomes between the two techniques. RLR does not compromise short-term and oncologic outcomes in patients with liver cancers.

Lichtenstein Versus Total Extraperitoneal Patch Plasty Versus Transabdominal Patch Plasty Technique for Primary Unilateral Inguinal Hernia Repair: A Registry-based, Propensity Score-matched Comparison of 57,906 Patients

OBJECTIVE

Outcome comparison of the Lichtenstein, total extraperitoneal patch plasty (TEP), and transabdominal patch plasty (TAPP) techniques for primary unilateral inguinal hernia repair.

BACKGROUND

For comparison of these techniques the number of cases included in meta-analyses of randomized controlled trials is limited. There is therefore an urgent need for more comparative data.

METHODS

In total, 57,906 patients with a primary unilateral inguinal hernia and 1-year follow up from the Herniamed Registry were selected between September 1, 2009 and February 1, 2015. Using propensity score matching, 12,564 matched pairs were formed for comparison of Lichtenstein versus TEP, 16,375 for Lichtenstein versus TAPP, and 14,426 for TEP versus TAPP.

RESULTS

Comparison of Lichtenstein versus TEP revealed disadvantages for the Lichtenstein operation with regard to the postoperative complications (3.4% vs 1.7%; P < 0.001), complication-related reoperations (1.1% vs 0.8%; P = 0.008), pain at rest (5.2% vs 4.3%; P = 0.003), and pain on exertion (10.6% vs 7.7%; P < 0.001). TEP had disadvantages in terms of the intraoperative complications (0.9% vs 1.2%; P = 0.035). Likewise, comparison of Lichtenstein versus TAPP showed disadvantages for the Lichtenstein operation with regard to the postoperative complications (3.8% vs 3.3%; P = 0.029), complication-related reoperations (1.2% vs 0.9%; P = 0.019), pain at rest (5% vs 4.5%; P = 0.029), and on exertion (10.2% vs 7.8%; P < 0.001).

CONCLUSIONS

TEP and TAPP were found to have advantages over the Lichtenstein operation.

Multicentre propensity score-matched study of laparoscopic versus open repeat liver resection for colorectal liver metastases

BACKGROUND

Repeat liver resection is often the best treatment option for patients with recurrent colorectal liver metastases (CRLM). Repeat resections can be complex, however, owing to adhesions and altered liver anatomy. It remains uncertain whether the advantages of a laparoscopic approach are upheld in this setting. The aim of this retrospective, propensity score-matched study was to compare the short-term outcome of laparoscopic (LRLR) and open (ORLR) repeat liver resection.

METHODS

A multicentre retrospective propensity score-matched study was performed including all patients who underwent LRLRs and ORLRs for CRLM performed in nine high-volume centres from seven European countries between 2000 and 2016. Patients were matched based on propensity scores in a 1 : 1 ratio. Propensity scores were calculated based on 12 preoperative variables, including the approach to, and extent of, the previous liver resection. Operative outcomes were compared using paired tests.

RESULTS

Overall, 425 repeat liver resections were included. Of 271 LRLRs, 105 were matched with an ORLR. Baseline characteristics were comparable after matching. LRLR was associated with a shorter duration of operation (median 200 (i.q.r. 123-273) versus 256 (199-320) min; P < 0·001), less intraoperative blood loss (200 (50-450) versus 300 (100-600) ml; P = 0·077) and a shorter postoperative hospital stay (5 (3-8) versus 6 (5-8) days; P = 0·028). Postoperative morbidity and mortality rates were similar after LRLR and ORLR.

CONCLUSION

LRLR for CRLM is feasible in selected patients and may offer advantages over an open approach.

Laparoscopic IPOM versus open sublay technique for elective incisional hernia repair: a registry-based, propensity score-matched comparison of 9907 patients

BACKGROUND

For comparison of laparoscopic IPOM versus sublay technique for elective incisional hernia repair, the number of cases included in randomized controlled trials and meta-analyses is limited. Therefore, an urgent need for more comparative data persists.

METHODS

In total, 9907 patients with an elective incisional hernia repair and 1-year follow-up were selected from the Herniamed Hernia Registry between September 1, 2009 and June 1, 2016. Using propensity score matching, 3965 (96.5%) matched pairs from 4110 laparoscopic IPOM and 5797 sublay operations were formed for comparison of the techniques.

RESULTS

Comparison of laparoscopic IPOM versus open sublay revealed disadvantages for the sublay operation regarding postoperative surgical complications (3.4% vs. 10.5%; p < 0.001), complication-related reoperations (1.5% vs. 4.7%; p < 0.001), and postoperative general complications (2.5% vs. 3.7%; p = 0.004). The majority of surgical postoperative complications were surgical site infection, seroma, and bleeding. Laparoscopic IPOM had disadvantages in terms of intraoperative complications (2.3% vs. 1.3%; p < 0.001), mainly bleeding, bowel, and other organ injuries. No significant differences in the recurrence and pain rates at 1-year follow-up were observed.

CONCLUSION

Laparoscopic IPOM was found to have advantages over the open sublay technique regarding the rates of both surgical and general postoperative complications as well as complication-related reoperations, but disadvantages regarding the rate of intraoperative complications.

Balance diagnostics after propensity score matching

Propensity score matching (PSM) is a popular method in clinical researches to create a balanced covariate distribution between treated and untreated groups. However, the balance diagnostics are often not appropriately conducted and reported in the literature and therefore the validity of the findings from the PSM analysis is not warranted. The special article aims to outline the methods used for assessing balance in covariates after PSM. Standardized mean difference (SMD) is the most commonly used statistic to examine the balance of covariate distribution between treatment groups. Because SMD is independent of the unit of measurement, it allows comparison between variables with different unit of measurement. SMD can be reported with plot. Variance is the second central moment and should also be compared in the matched sample. Finally, a correct specification of the propensity score model (e.g., linearity and additivity) should be re-assessed if there is evidence of imbalance between treated and untreated. R code for the implementation of balance diagnostics is provided and explained.

A propensity score-matched analysis of robotic versus open pancreatoduodenectomy for pancreatic cancer based on margin status

BACKGROUND

No study has shown the oncologic non-inferiority of robotic pancreatoduodenectomy (RPD) versus open pancreatoduodenectomy (OPD) for pancreatic cancer (PC).

METHODS

This is a single institution propensity score matched study comparing RPD and ODP for resectable PC, based on factors predictive of R1 resection (≤ 1 mm). Only patients operated on after completion of the learning curve in both procedures and for whom circumferential margins were assessed according to the Leeds pathology protocol were included. The primary study endpoint was the rate of R1 resection. Secondary study endpoints were as follows: number of examined lymph nodes (N), rate of perioperative transfusions, percentage of patients receiving adjuvant therapies, occurrence of local recurrence, overall survival, disease-free survival, and sample size calculation for randomized controlled trials (RCT).

RESULTS

Factors associated with R1 resection were tumor diameter, number of positive N, N ratio, logarithm odds of positive N, and duodenal infiltration. The matching process identified 20 RPDs and 24 OPDs. All RPDs were completed robotically. R1 resection was identified in 11 RPDs (55.0%) and in 10 OPDs (41.7%) (p = 0.38). There was no difference in the rate of R1 at each margin as well as in the proportion of patients with multiple R1 margins. RPD and OPD were also equivalent with respect to all secondary study endpoints, with a trend towards lower rate of blood transfusions in RPD. Based on the figures presented herein, a non-inferiority RCT comparing RPD and OPD having the rate of R1 resection as the primary study endpoint requires 3355 pairs.

CONCLUSIONS

RPD and OPD achieved the same rate of R1 resections in resectable PC. RPD was also non-inferior to OPD with respect to all secondary study endpoints. Because of the high number of patients required to run a RCT, further assessment of RPD for PC would require the implementation of an international registry.

Outcome of laparoscopic paraesophageal hernia repair in octogenarians: a registry-based, propensity score-matched comparison of 360 patients

Background

Paraesophageal hernias (PEH) tend to occur in elderly patients and the assumed higher morbidity of PEH repair may dissuade clinicians from seeking a surgical solution. On the other hand, the mortality rate for emergency repairs shows a sevenfold increase compared to elective repairs. This analysis evaluates the complication rates after elective PEH repair in patients 80 years and older in comparison with younger patients.

Methods

In total, 3209 patients with PEH were recorded in the Herniamed Registry between September 1, 2009 and January 5, 2018. Using propensity score matching, 360 matched pairs were formed for comparative analysis of general, intraoperative, and postoperative complication rates in both groups.

Results

Our analysis revealed a disadvantage in general complications (6.7% vs. 14.2%; p = 0.002) for patients ≥ 80 years old. No significant differences were found between the two groups for intraoperative (4.7% vs. 5.8%, p = 0.627) and postoperative complications (2.2% vs. 2.8%, p = 0.815) or for complication-related reoperations (1.7% vs. 2.2%, p = 0.791).

Conclusions

Despite a higher risk of general complications, PEH repair in octogenarians is not in itself associated with increased rates of intraoperative and postoperative complications or associated reoperations. Therefore, PEH repair can be safely offered to elderly patients with symptomatic PEH, if general medical risk factors are controlled.

Electronic supplementary material

The online version of this article (10.1007/s00464-018-06619-4) contains supplementary material, which is available to authorized users.

Platelet-rich plasma versus hyaluronic acid injections for knee osteoarthritis: a propensity-score analysis

BACKGROUND AND AIMS

Intra-articular injections of viscosupplements have been an option in the treatment of knee osteoarthritis. Platelet-rich plasma is an experimental treatment in osteoarthritis. Previous studies have shown that platelet-rich plasma reduces osteoarthritis symptoms in similar proportions as viscosupplements. The aim of this study was to compare platelet-rich plasma versus viscosupplements in terms of symptoms' relief and time to arthroplasty.

MATERIAL AND METHODS

A total of 190 patients included in this retrospective study received either intra-articular injections of platelet-rich plasma (94 patients) or hyaluronic acid (86 patients) between January 2014 and October 2017. Western Ontario and McMaster Universities Osteoarthritis Index, Visual Analogue Scale, and range of motion were measured before injection, at 15 days, 6 months, 12 months, and at last follow-up. We compared outcomes between these two groups using propensity score analysis for risk adjustment in multivariate analysis and for one-to-one matching.

RESULTS

Hyaluronic acid-treated patients experienced a higher arthroplasty rate (36.0% vs 5.3%, p < 0.001), lower range of motion, worse Visual Analogue Scale and Western Ontario and McMaster Universities Osteoarthritis Index scores, and increased risk of any arthroplasty occurrence (log-rank < 0.001) than platelet-rich plasma patients. Cox proportional hazards analysis revealed a tendency to decrease the risk of knee arthroplasty for the patients treated by platelet-rich plasma (hazard ratio = 0.23, 95% confidence interval, 0.05-1.05, p = 0.058). When the treatment method was adjusted for propensity score in the propensity score-matched pairs (n = 78), we found that platelet-rich plasma group still showed significant improvement over the hyaluronic acid group in arthroplasty rate (12.8% vs 41.0%, p = 0.010), Visual Analogue Scale and Western Ontario and McMaster Universities Osteoarthritis Index scores, but not in the range of motion, during the mean follow-up of 16.7 months.

CONCLUSION

Intra-articular injections of platelet-rich plasma associated with better outcomes than hyaluronic acid in knee osteoarthritis. Platelet-rich plasma might prolong the time to arthroplasty and provide a valid therapeutic option in selected patients with knee osteoarthritis not responding to conventional treatments. Further larger studies are needed to validate this promising treatment modality.

Analyses of clinical outcomes after severe pelvic fractures: an international study

Background

This study aimed to compare treatment outcomes between patients with severe pelvic fractures treated at a representative trauma center that was established in Korea since 2015 and matched cases treated in the USA.

Methods

Two cohorts were selected from a single institution trauma database in South Korea (Ajou Trauma Data Bank (ATDB)) and the National Trauma Data Bank (NTDB) in the USA. Adult blunt trauma patients with a pelvic Abbreviated Injury Scale >3 were included. Patients were matched based on covariates that affect mortality rate using a 1:1 propensity score matching (PSM) approach. We compared differences in outcomes between the two groups, performed survival analysis for the cohort after PSM and identified factors associated with mortality. Lastly, we analyzed factors related to outcomes in the ATDB dataset comparing a period prior to the implementation of the trauma center according to US standards, an interim period and a postimplementation period.

Results

After PSM, a total of 320 patients (160 in each cohort) were identified for comparison. Inhospital mortality was significantly higher in the ATDB cohort using χ² test, but it was not statistically significant when using Kaplan-Meier survival curves and Cox regression analysis. Moreover, the mortality rate was similar comparing the NTDB cohort to ATDB data reflecting the post-trauma center establishment period. Older age, lower systolic blood pressure (SBP) and Glasgow Coma Scale (GCS) at admission were factors associated with mortality.

Discussion

Mortality rate after severe pelvic fractures was significantly associated with older age, lower SBP and GCS scores at admission. Efforts to establish a trauma center in South Korea led to improvement in outcomes, which are comparable to those in US centers.

Level of evidence

Level IV.

Has Shouldice Repair in a Selected Group of Patients with Inguinal Hernia Comparable Results to Lichtenstein, TEP and TAPP Techniques?

Background

In the new international guidelines only the mesh-based Lichtenstein, TEP and TAPP techniques are recommended. This present analysis of data from the Herniamed Registry compares the outcome for Shouldice versus Lichtenstein, TEP and TAPP.

Methods

Propensity score matching analyses were performed to obtain homogeneous comparison groups for Shouldice versus Lichtenstein (n = 2115/2608; 81.1%), Shouldice versus TEP (n = 2225/2608; 85.3%) and Shouldice versus TAPP (2400/2608; 92.0%).

Results

The most important characteristics of the Shouldice patient collective were younger patients with a mean age of 40 years, a large proportion of women of 30%, a mean BMI value of 24 and a proportion of defect sizes up to 3 cm of over 85%. For this selected patient collective, propensity score matched-pair analysis did not identify any difference in the perioperative and one-year follow-up outcome compared with TAPP, fewer intraoperative (0.5 vs. 1.3%; p = 0.009) but somewhat more postoperative complications (2.3 vs. 1.5%; p = 0.050) compared with TEP and advantages with regard to pain at rest (4.6 vs. 6.1%; p = 0.039) and on exertion (10.0 vs. 13.4%; p < 0.001) compared with the Lichtenstein technique.

Conclusion

For a selected group of patients the Shouldice technique can be used for primary unilateral inguinal hernia repair while achieving an outcome comparable to that of Lichtenstein, TEP and TAPP operations.

[Propensity score: Interests, use and limitations. A practical guide for clinicians]

Propensity scores have been proposed in the early 1980s, and are increasingly used in epidemiology since the 2000s. They are is used to minimize the selection bias in observational studies, leading to a comparability between the exposure groups close to that observed in randomized trials. However, they have important limitations. Besides, new statistical techniques to improve the propensity score performances are more and more complex, while the build and the use of propensity score require a strict methodology to avoid bias, imprecision and non-reproducibility. This overview, designed for clinicians, is aimed at describing the advantages, techniques of use and limitations of propensity scores. A reading grid is provided in order to help interpreting studies using propensity scores.

Salvage liver transplantation or repeat hepatectomy for recurrent hepatocellular carcinoma: An intent-to-treat analysis

The salvage liver transplantation (LT) strategy was conceived for initially resectable and transplantable hepatocellular carcinoma (HCC) to obviate upfront transplantation, with salvage LT in the case of recurrence. The longterm outcomes of a second resection for recurrent HCC have improved. The aim of this study was to perform an intention-to-treat analysis of overall survival (OS) comparing these 2 strategies for initially resectable and transplantable recurrent HCC. From 1994 to 2011, 391 patients with HCC who underwent salvage LT (n = 77) or a second resection (n = 314) were analyzed. Of 77 patients in the salvage LT group, 21 presented with resectable and transplantable recurrent HCC and 18 underwent transplantation. Of 314 patients in the second resection group, 81 presented with resectable and transplantable recurrent HCC and 81 underwent a second resection. The 5-year intention-to-treat OS rates, calculated from the time of primary hepatectomy, were comparable between the 2 strategies (72% for salvage transplantation versus 77% for second resection; P = 0.57). In patients who completed the salvage LT or second resection procedure, the 5-year OS rates, calculated from the time of the second surgery, were comparable between the 2 strategies (71% versus 71%; P = 0.99). The 5-year disease-free survival (DFS) rates were 72% following transplantation and 18% following the second resection (P < 0.001). Similar results were observed after propensity score matching. In conclusion, although the 5-year OS rates were similar in the salvage LT and second resection groups, the salvage LT strategy still achieves better DFS. Second resection for recurrent HCC might be considered to be the best alternative option to LT in the current organ shortage. Liver Transplantation 23 1553-1563 2017 AASLD.

Postoperative Outcomes of Minimally Invasive Gastrectomy Versus Open Gastrectomy During the Early Introduction of Minimally Invasive Gastrectomy in the Netherlands: A Population-based Cohort Study

OBJECTIVE

To compare postoperative outcomes of minimally invasive gastrectomy (MIG) to open gastrectomy (OG) for cancer during the introduction of MIG in the Netherlands.

BACKGROUND

Between 2011 and 2015, the use of MIG increased from 4% to 53% in the Netherlands.

METHODS

This population-based cohort study included all patients with curable gastric adenocarcinoma that underwent gastrectomy between 2011 and 2015, registered in the Dutch Upper GI Cancer Audit. Patients with missing preoperative data, and patients in whom no lymphadenectomy or reconstruction was performed were excluded. Propensity score matching was applied to create comparable groups between patients receiving MIG or OG, using year of surgery and other potential confounders. Morbidity, mortality, and hospital stay were evaluated.

RESULTS

Of the 1697 eligible patients, 813 were discarded after propensity score matching; 442 and 442 patients who underwent MIG and OG, respectively, remained. Conversions occurred in 10% of the patients during MIG. Although the overall postoperative morbidity (37% vs 40%, P = 0.489) and mortality rates (6% vs 4%, P = 0.214) were comparable between the 2 groups, patients who underwent MIG experienced less wound complications (2% vs 5%, P = 0.006). Anastomotic leakage occurred in 8% of the patients after MIG, and in 7% after OG (P = 0.525). The median hospital stay declined over the years for both procedures (11 to 8 days, P < 0.001). Overall, hospital stay was shorter after MIG compared with OG (8 vs 10 days, P < 0.001).

CONCLUSIONS

MIG was safely introduced in the Netherlands, with overall morbidity and mortality comparable with OG, less wound complications and shorter hospitalization.

Two-stage treatment in patients with patients with high-energy femoral fractures does not lead to an increase in deep infectious complications: a propensity score analysis

Purpose

In patients following severe trauma sometimes the physiological condition or soft tissue status may not allow definitive fixation of a femoral fracture. In these patients, an external fixator can be placed to temporarily stabilise the fracture, after which definitive fixation can be performed in a second procedure. The aim of this study was to compare the postoperative wound infection and union rates of patients treated with direct intramedullary nailing (IMN) and patients treated with the ‘two-stage treatment’.

Methods

All patients with high-energy femoral fractures treated with IMN between 2000 and 2016 in a single Level 1 trauma centre were eligible. Electronic charts were reviewed for patient and surgical characteristics; furthermore, the development of complications was noted. A propensity score analysis was performed to assess the attributed risk of the external fixator on the development of postoperative wound infections.

Results

A total of 149 patients were included in this study; 93 underwent direct IMN and 56 underwent the two-stage treatment. Patients who underwent two-stage treatment were more severely injured, reflected by lower EMV and higher ISS on admission. Patients in the two-stage treatment group had a significant higher risk of postoperative wound infections (OR: 4.698, 95% CI: 1.203–18.339) but not a higher risk on deep postoperative wound infections (OR 2.345, 95% CI: 0.439–12.540). Union rate did not differ between the two groups (94% vs 94% NS).

Conclusions

The two-stage treatment is a safe treatment option in patients with a high-energy femoral fracture in terms of postoperative wound infections. Union rates are also comparable between the two treatment groups.