A cumulative analysis of an individual surgeon's early experience with elective open abdominal aortic aneurysm repair

Which Factors Affect the Stress of Intraoperative Orthopedic Surgeons by Using Electroencephalography Signals and Heart Rate Variability?

Can we recognize intraoperative real-time stress of orthopedic surgeons and which factors affect the stress of intraoperative orthopedic surgeons with EEG and HRV? From June 2018 to November 2018, 265 consecutive records of intraoperative stress measures for orthopedic surgeons were compared. Intraoperative EEG waves and HRV, comprising beats per minute (BPM) and low frequency (LF)/high frequency (HF) ratio were gathered for stress-associated parameters. Differences in stress parameters according to the experience of surgeons, intraoperative blood loss, and operation time depending on whether or not a tourniquet were investigated. Stress-associated EEG signals including beta 3 waves were significantly higher compared to EEG at rest for novice surgeons as the procedure progressed. Among senior surgeons, the LF/HF ratio reflecting the physical demands of stress was higher than that of novice surgeons at all stages. In surgeries including tourniquets, operation time was positively correlated with stress parameters including beta 1, beta 2, beta 3 waves and BPM. In non-tourniquet orthopedic surgeries, intraoperative blood loss was positively correlated with beta 1, beta 2, and beta 3 waves. Among orthopedic surgeons, those with less experience demonstrated relatively higher levels of stress during surgery. Prolonged operation time or excessive intraoperative blood loss appear to be contributing factors that increase stress.

The Association Between a Surgeon’s Learning Curve With Endovascular Aortic Aneurysm Repair and Previous Institutional Experience

The purpose of the present study was to determine whether an institution’s prior endovascular experience influenced the learning curve of subsequent surgeons. A prospective analysis of the initial 70 endovascular abdominal aortic aneurysm repair (EVAR) cases attempted by an individual surgeon was performed with the primary outcome variable being achievement and 30-day maintenance of initial clinical success. Along with standard statistical analyses, the cumulative sum failure method (CUSUM) was used to analyze the learning curve, with a predetermined acceptable failure rate of 10%. Seventy elective EVAR cases were performed by this surgeon during a 4-year period (2000-2004) (mean age, 73.7 ∓ 5.4 years; mean aneurysm diameter 63.3 ∓ 7.2 mm). Initial clinical success was achieved in 68 of 70 cases (97%), which differed significantly with that of our initial surgeon (88.5%, P = .01). Causes of failure in the present series included 1 early mortality (1.4%) and 1 case of conversion to open repair with no instances of type I endoleak or endograft limb thrombosis. Both surgeons’ cases were plotted sequentially with CUSUM curves revealing a significantly shorter learning curve for the second surgeon. Optimal results were achieved following 10 to 20 EVAR cases, as opposed to 60 cases in the initial series. Such an analysis confirms that as an institution’s experience with EVAR increases, an individual surgeon’s learning curve shortens considerably.

Lessons learned from a comparative analysis of surgical outcomes of and learning curves for laparoscopy-assisted distal gastrectomy

Purpose

Before expanding our indications for laparoscopic gastrectomy to advanced gastric cancer and adopting reduced port laparoscopic gastrectomy, we analyzed and audited the outcomes of laparoscopy-assisted distal gastrectomy (LADG) for adenocarcinoma; this was done during the adoptive period at our institution through the comparative analysis of short-term surgical outcomes and learning curves (LCs) of two surgeons with different careers.

Materials and Methods

A detailed comparative analysis of the LCs and surgical outcomes was done for the respective first 95 and 111 LADGs performed by two surgeons between July, 2006 and June, 2011. The LCs were fitted by using the non-linear ordinary least squares estimation method.

Results

The postoperative morbidity and mortality rates were 14.6% and 0.0%, respectively, and there was no significant difference in the morbidity rates (12.6% vs. 16.2%, P=0.467). More than 25 lymph nodes were retrieved by each surgeon during LADG procedures. The LCs of both surgeons were distinct. In this study, a stable plateau of the LC was not achieved by both surgeons even after performing 90 LADGs.

Conclusions

Regardless of the experience with gastrectomy or laparoscopic surgery for other organs, or the age of surgeon, the outcome was quite acceptable; the learning process differ according to the surgeon's experience and individual characteristics.

Learning curve for the management of recurrent and locally advanced primary rectal cancer: a single team's experience

AIM

The study aimed to define the learning curve required to gain satisfactory training to perform pelvic exenterative surgery for recurrent or locally advanced primary rectal cancer.

METHOD

Consecutive patients undergoing exenterative pelvic surgery for recurrent and locally advanced primary rectal cancer, by one surgical team, between 2006 and 2011 were studied. They were divided into quartiles (Q1-Q4) according to the date of surgery. A risk-adjusted cumulative sum (RA-CUSUM) model was used to evaluate the learning curve. The chi-squared test with gamma ordinal was used to assess the change with time in the four quartiles.

RESULTS

One hundred patients (70 males; median age 61 (25-85) years; 55 primary cancers) were included in the study. Thirty patients underwent abdominosacral resection. The number of patients who underwent plastic reconstruction (n = 53) increased from 12 in Q1 to 15 in Q4 (P = 0.781). The median operation time, intra-operative blood loss and hospital stay were 8 (3-17) h, 1.5 (0.1-17) l and 15 (9-82) days respectively. There was no significant change with time. Complete resection (R0) was achieved in 78 patients. Microscopic (R1) or macroscopic (R2) residual disease was present in 15 and seven patients respectively. The number of major complications was 20, and minor 30. RA-CUSUM analysis demonstrated an improvement in any complications after 14, in major after 12 and in minor after 25 operations.

CONCLUSION

Pelvic exenterative surgery for recurrent or locally advanced primary rectal cancer is complex and requires a minimum of 14 cases for an expert colorectal surgeon to gain the desirable training and experience to improve morbidity.

Determination of patient preference for location of elective abdominal aortic aneurysm surgery

OBJECTIVE

Aneurysm repair is centralized in higher volume centers resulting in reduced mortality, with longer travel distances. The purpose of this study is to explore patients' preference between local care versus longer distances and lower mortality rates.

METHODS

Patients with abdominal aortic aneurysm (AAA) measuring 4 to 5 cm and living at least a 1-hour drive from our hospital were asked to assume it had grown to 5.5 cm, and repair was recommended with a mortality risk of 2%. The level of additional risk they would accept to undergo surgery locally was determined.

RESULTS

A total of 67 patients were surveyed. If mortality risk was equivalent at the local and regional hospitals, 44% preferred care at our tertiary center, while 56% preferred surgery locally. If perioperative mortality was increased at the local hospital, 9% preferred local surgery.

CONCLUSIONS

The vast majority of patients with AAA will accept longer travel distances for care as long as it results in a reduction in perioperative mortality.

Comparison of Learning Curves and Clinical Outcomes between Laparoscopy-assisted Distal Gastrectomy and Open Distal Gastrectomy

PURPOSE

Most stomach surgeons have been educated sufficiently in conventional open distal gastrectomy (ODG) but insufficiently in laparoscopy-assisted distal gastrectomy (LADG). We compared learning curves and clinical outcomes between ODG and LADG by a single surgeon who had sufficient education of ODG and insufficient education of LADG.

MATERIALS AND METHODS

ODG (90 patients, January through September, 2004) and LADG groups (90 patients, June 2006 to June 2007) were compared. The learning curve was assessed with the mean number of retrieved lymph nodes, operation time, and postoperative morbidity/mortality.

RESULTS

Mean operation time was 168.3 minutes for ODG and 183.6 minutes for LADG. The mean number of retrieved lymph nodes was 37.9. Up to about the 20th to 25th cases, the slope decrease in the learning curve for LADG was more apparent than for ODG, although they both reached plateaus after the 50th cases. The mean number of retrieved lymph nodes reached the overall mean after the 30th and 40th cases for ODG and LADG, respectively. For ODG, complications were evenly distributed throughout the subgroups, whereas for LADG, complications occurred in 10 (33.3%) of the first 30 cases.

CONCLUSIONS

Compared with conventional ODG, LADG is feasible, in particular for a surgeon who has had much experience with conventional ODG, although LADG required more operative time, slightly more time to get adequately retrieved lymph nodes and more complications. However, there were more minor problems in the first 30 LADG than ODG cases. The unfavorable results for LADG can be overcome easily through an adequate training program for LADG.

Impact of the introduction of endovascular aneurysm repair in high-risk patients on our practice of elective treatment of infrarenal abdominal aortic aneurysms

The aim of this work was to evaluate, in terms of activity and immediate postoperative results, the modifications of our elective surgical treatment of infrarenal abdominal aortic aneurysms (AAAs) resulting from the use of stent grafts to treat AAAs, following the recommendations issued by the French Health Products Safety Agency (AFSSAPS) in December 2003. This monocentric and retrospective study used the clinical data of patients operated on for asymptomatic AAA between January 2001 and December 2006. Endovascular treatment of AAAs with aortic stent grafts was introduced in our current practice in January 2004, following the recommendations of the AFSSAPS (high-risk patients for open surgery presenting with an AAA > or =50 mm). Group I was composed of patients operated on between January 2001 and December 2003 according to the standard open technique. Group II was composed of patients operated on between January 2004 and December 2006 with either standard open surgery or endovascular surgery. The main criteria of evaluation were the number of operated patients, their American Society of Anesthesiology (ASA) score of surgical risk, and the intrahospital morbidity and mortality. The number of treated patients significantly increased between these two periods (group I n = 49, group II n = 88, with 38 endovascular treatments; p < 0.001), without any changes in average age (70 vs. 72 years), percentage of men (93.7% vs. 95.5%), and mean AAA size (57.8 vs. 56 mm) between the two groups. ASA scores were significantly higher in group II (ASA III and IV, group I = 20.4% vs. group II = 55.7%; p < 0.0001), whereas the intrahospital mortality rate (4.1% vs. 3.4%) and the rate of major postoperative complications (16.3% vs. 11%) have remained stable. In group II, the median duration of hospitalization was significantly reduced (12 vs. 9 days, p < 0.001). In conclusion, in our center, following the AFSSAPS recommendations, the introduction of endovascular treatment has enabled us to electively treat a greater number of AAA patients with higher surgical risk, without aggravating the immediate postoperative results.

Learning curve analysis of thoracic endovascular aortic repair in relation to credentialing guidelines

OBJECTIVE

Recently, practice guideline documents have recommended the completion of different levels of interventional experience and 5 or 10 thoracic endovascular aortic cases prior to surgeon credentialing. This study's purpose was to determine whether these requirements are valid by reviewing three surgeons' learning curves with thoracic aortic endovascular repairs.

METHODS

Between 1998 and 2006, 67 patients underwent emergent or elective endovascular repair of thoracic aortic pathologies by one of three vascular surgeons with extensive experience with catheter manipulation and abdominal aortic endografts. Following standard retrospective review, each surgeon's learning curve was analyzed using the cumulative sum failure method with a target success rate of 95% derived from the literature. The main outcome variable was primary technical success.

RESULTS

These 67 patients presented with several pathologies including elective (n = 31) and ruptured (n = 11) thoracic aortic aneurysms, acute dissections or aortic ulcers (n = 10), and acute blunt thoracic aortic trauma (n = 15). The mean age was 65 (range: 20 to 90) and the early (30 day) mortality rate was 19.4% in urgent cases (n = 36) and 0% in elective cases (n = 31). Paraplegia occurred in two patients (3%). Primary technical success was achieved in 62 cases (92.5%) and did not differ between surgeons (92.6%, 91.3%, 94.1%, respectively; P = .9). Each surgeon's cases were plotted sequentially and the resulting learning curves were similar. Although acceptable outcomes were obtained throughout the study period, improved results, compared with the target success rate, were not achieved until each surgeon treated 5 to 10 patients.

CONCLUSION

This study supports the case volume requirements of the Society for Vascular Surgery credentialing guidelines, which also requires extensive catheter and guidewire experience. With this background in catheter manipulation and endovascular abdominal aortic repair, surgeons can achieve optimal outcomes with thoracic aortic lesions following 5 to 10 cases.

Elective surgery for aortic abdominal aneurysm: comparison of English outcomes with those elsewhere

INTRODUCTION

The aim of this study was to quantify mortality after elective repair of abdominal aortic aneurysm (AAA) in England, and to compare English case fatality rates (CFRs) with those reported in the literature.

PATIENTS AND METHODS

English Hospital Episode Statistics (HES) for the financial years 1998/9 to 2001/2, linked to death data, were analysed. A systematic literature search was undertaken to identify studies reporting CFRs after elective AAA surgery. The CFR in England was compared with these studies by using confidence intervals on the CFRs and funnel plot techniques.

RESULTS

In the English study, elective repair of AAA was performed on 11,338 patients of whom 771 died within 30 days after surgery (6.8%). The literature search found 66 studies: 34 reported mortality rates that were within the 99% confidence limits of the English rates, 31 below, and one study above.

DISCUSSION

The CFR after elective surgical repair in England within 30 days of operation (6.8%) was higher than expected from the literature. Differences between England and other countries in quality of care is one possible explanation for the findings, but other explanations are possible and are discussed.

SCORING SYSTEMS DO NOT ACCURATELY PREDICT OUTCOME FOLLOWING ABDOMINAL AORTIC ANEURYSM REPAIR

BACKGROUND

Abdominal aortic aneurysm repair is associated with significant morbidity and mortality. This study aims to evaluate the efficiency of scoring systems in a group of patients undergoing abdominal aortic aneurysm repair.

METHODS

A prospective study of 152 patients undergoing aneurysm repair was conducted. Each patient was scored according to the Acute Physiology and Chronic Health Evaluation II, Physiological and Operative Severity Score for the enUmeration of Mortality and Morbidity and Simplified Acute Physiology Score II systems. The predicted mortality for each patient was calculated. Chi(2) analysis was carried out to determine the accuracy of mortality predictions. Receiver-operator curves were drawn to compare scoring systems in terms of sensitivity and specificity.

RESULTS

In the elective aneurysm repair group, all scoring systems tended to overestimate mortality. Receiver-operator curves showed inaccuracies in identifying patients who were at high risk from surgery. In contrast, predicted mortalities underestimated the true death rate among the ruptured aneurysm group. Receiver-operator curves showed better efficiency of scoring systems in the ruptured aneurysm group than in the elective repair group. There was no significant correlation between predicted and observed mortalities in either group.

CONCLUSION

In this study, all systems showed significant errors when predicting mortality. Therefore, although useful as an audit tool, scoring systems should not be used on an individual basis to guide treatment and assess prognosis after surgery.

Multidimensional learning curve in laparoscopy-assisted gastrectomy for early gastric cancer

BACKGROUND

Laparoscopy-assisted gastrectomy (LAG) is a complex and time-consuming procedure, which is increasingly used for early gastric cancer (EGC). We provide a multidimensional analysis of the learning curve in LAG.

METHODS

Cumulative sum method was used to analyze outcomes of 109 patients undergoing LAG for EGC by one surgeon over a two year period; the influence of patient selection was evaluated. Target failure rate was set at 10%, with failure defined as open conversion, mortality, major morbidity, residual tumor, or inappropriate lymphadenectomy.

RESULTS

There were 19 failures--fourteen performance and five oncologic. The learning curve, which displayed a slight rising trend and three phases was achieved after 40 cases with selected patients; it was broken, however, by the introduction of advanced procedures and unselected patients.

CONCLUSIONS

Advanced procedures and broad indications in LAG should be delayed until a learning curve is completed under the target failure rate.

Direct comparison of risk-adjusted and non–risk-adjusted CUSUM analyses of coronary artery bypass surgery outcomes

OBJECTIVE

We previously applied non-risk-adjusted cumulative sum methods to analyze coronary bypass outcomes. The objective of this study was to assess the incremental advantage of risk-adjusted cumulative sum methods in this setting.

METHODS

Prospective data were collected in 793 consecutive patients who underwent coronary bypass grafting performed by a single surgeon during a period of 5 years. The composite occurrence of an "adverse outcome" included mortality or any of 10 major complications. An institutional logistic regression model for adverse outcome was developed by using 2608 contemporaneous patients undergoing coronary bypass. The predicted risk of adverse outcome in each of the surgeon's 793 patients was then calculated. A risk-adjusted cumulative sum curve was then generated after specifying control limits and odds ratio. This risk-adjusted curve was compared with the non-risk-adjusted cumulative sum curve, and the clinical significance of this difference was assessed.

RESULTS

The surgeon's adverse outcome rate was 96 of 793 (12.1%) versus 270 of 1815 (14.9%) for all the other institution's surgeons combined (P = .06). The non-risk-adjusted curve reached below the lower control limit, signifying excellent outcomes between cases 164 and 313, 323 and 407, and 667 and 793, but transgressed the upper limit between cases 461 and 478. The risk-adjusted cumulative sum curve never transgressed the upper control limit, signifying that cases preceding and including 461 to 478 were at an increased predicted risk. Furthermore, if the risk-adjusted cumulative sum curve was reset to zero whenever a control limit was reached, it still signaled a decrease in adverse outcome at 166, 653, and 782 cases.

CONCLUSIONS

Risk-adjusted cumulative sum techniques provide incremental advantages over non-risk-adjusted methods by not signaling a decrement in performance when preoperative patient risk is high.

Risk-adjusted analysis of early mortality after ruptured abdominal aortic aneurysm repair

PURPOSE

Ruptured abdominal aortic aneurysms (RAAAs) continue to result in early mortality in up to 50% of patients. Additionally, it remains difficult to compare outcomes given the variability in patient comorbidities and presentation. The purpose of this study was to describe an instrument that permits the prospective analysis of outcomes after RAAA repair while adjusting for the variability in preoperative risk.

METHODS

Consecutive patients undergoing attempted open RAAA repair over a 5-year period (1999 to 2003) at our center were reviewed. Thirty-day or in-hospital mortality was the main outcome variable. Preoperative mortality risk was estimated for each patient by using a validated modification of the POSSUM scoring system (V-POSSUM). A risk-adjusted cumulative sum method (RA-CUSUM) was used to compare observed versus predicted outcomes by assigning a risk-adjusted score, based on log-likelihood ratios, to each patient. These scores were sequentially plotted with preset control limits to allow for "signaling" when results were substantially different from expected (doubling or halving of odds ratios).

RESULTS

A total of 136 patients were reviewed, with an early mortality rate of 45.6%. V-POSSUM scores were accurate in predicting mortality for the entire cohort, with an observed-to-predicted mortality ratio of 0.92 (P = .80). Each patient's risk-adjusted score was plotted sequentially. In one segment of the resulting plot, the graph adopted a negative slope and crossed the lower control limit, indicating improved results compared with predicted.

CONCLUSIONS

V-POSSUM scores in this series accurately predicted early mortality after RAAA surgery. The RA-CUSUM method allows for the prospective evaluation of outcomes, while taking into account patient variability. In the current study, this resulted in the identification of a series of patients who had improved outcomes compared with predicted.