Decision analysis in surgery

An Analysis of the Decision-Making Process After “Decision not to Operate” in Acutely Unwell, High-Risk General Surgery Patients

Objectives:

The purpose of this study was to analyze the decision-making process in emergency general surgery in an attempt to ascertain whether surgeons make the correct decision when decisions not to operate in high-risk acutely unwell surgical patients are taken.

Background:

A decision not to operate is sometimes associated with a certain degree of uncertainty as to the accuracy of the decision. Difficulty lies with the fact that the decisions are made on assumptions, and the tools available are not fool proof.

Methods:

We retrospectively evaluated “decisions not to operate” over a period of 32 months from April 2013 to August 2015 in a district general hospital in United Kingdom and compared with consecutive similar number of patients who had an operation as recorded in the National Emergency Laparotomy Audit (NELA) database (from January 2014 to August 2015). We looked at the demographics, American Society of Anesthesiologists grade, Portsmouth–Physiological and Operative Severity Score for enumeration of Mortality and Morbidity (P-POSSUM) score, functional status, and 30-day mortality.

Results:

Two groups (operated [n = 43] and conservative [n = 42]) had similar characteristics. Patients for conservative management had a higher P-POSSUM score ( P < .001) and a poorer functional status ( P < .001) at the time of decision-making compared to those who had surgery. Mortality at 30 days was significantly higher for patients decided for conservative management when compared with those who had surgery (76.2% and 18.6%, respectively).

Conclusions:

Elderly patients with poorer functional status and predicted risks more often drive multidisciplinary discussions on whether to operate. Within the limitations of not knowing the outcome otherwise, it appears surgeons take a reasonable approach when deciding not to operate.

Surgeon Perception of Risk and Benefit in the Decision to Operate

OBJECTIVE

To determine how surgeons' perceptions of treatment risks and benefits influence their decisions to operate.

BACKGROUND

Little is known about what makes one surgeon choose to operate on a patient and another chooses not to operate.

METHODS

Using an online study, we presented a national sample of surgeons (N = 767) with four detailed clinical vignettes (mesenteric ischemia, gastrointestinal bleed, bowel obstruction, appendicitis) where the best treatment option was uncertain and asked them to: (1) judge the risks (probability of serious complications) and benefits (probability of recovery) for operative and nonoperative management and (2) decide whether or not they would recommend an operation.

RESULTS

Across all clinical vignettes, surgeons varied markedly in both their assessments of the risks and benefits of operative and nonoperative management (narrowest range 4%-100% for all four predictions across vignettes) and in their decisions to operate (49%-85%). Surgeons were less likely to operate as their perceptions of operative risk increased [absolute difference (AD) = -29.6% from 1.0 standard deviation below to 1.0 standard deviation above mean (95% confidence interval, CI: -31.6, -23.8)] and their perceptions of nonoperative benefit increased [AD = -32.6% (95% CI: -32.8,--28.9)]. Surgeons were more likely to operate as their perceptions of operative benefit increased [AD = 18.7% (95% CI: 12.6, 21.5)] and their perceptions of nonoperative risk increased [AD = 32.7% (95% CI: 28.7, 34.0)]. Differences in risk/benefit perceptions explained 39% of the observed variation in decisions to operate across the four vignettes.

CONCLUSIONS

Given the same clinical scenarios, surgeons' perceptions of treatment risks and benefits vary and are highly predictive of their decisions to operate.

Outcomes research in rheumatoid arthritis

Although rheumatoid arthritis causes significant disability for more than 1 million individuals in the United States, prior research regarding surgical treatment options has been limited by study sample size, study design, and methods of comparison. Furthermore, there is wide variation in the referral pattern for hand surgery consideration and type of surgical treatment of rheumatoid hand disease, yet the reasons for these differences are unclear. This review describes the role of outcomes research in rheumatoid hand disease by summarizing variations in surgical treatment, detailing current outcome assessment strategies, and offering potential strategies for designing future studies for rheumatoid hand disease.

Total wrist arthroplasty and total wrist arthrodesis in rheumatoid arthritis: a decision analysis from the hand surgeons' perspective

PURPOSE

Treatment of severely destroyed rheumatoid wrists with total wrist arthroplasty or total wrist arthrodesis relies on patient and surgeon preferences rather than rigorous prospective outcomes data. The purpose of this study is to develop a decision analytic model of arthroplasty and arthrodesis in rheumatoid arthritis (RA) using utility values obtained from a random sample of hand surgeons.

METHODS

A utility survey using a time trade-off design was administered to 175 members of the American Society for Surgery of the Hand. Based on the results of the survey, the utility values that surgeons assign to health states associated with arthroplasty and arthrodesis and their complications were calculated. By combining utility values with complication rates in the published literature, we developed a decision tree to calculate the expected quality-adjusted life years (QALYs) for each procedure compared to living with a painful RA wrist.

RESULTS

Based on surgeon preferences, living for 30 years with a painful, poorly functioning RA wrist (utility = 0.54) is associated with 16.2 QALYs. Treatment with arthroplasty (utility = 0.85) is associated with 25.5 QALYs, a gain of 9.3 QALYs over nonsurgical management. Arthrodesis (utility = 0.82) is associated with 24.6 QALYs, a gain of 8.4 QALYs over nonsurgical management. Arthroplasty is associated with a small incremental increase in QALYs (0.9) compared to arthrodesis.

CONCLUSIONS

Based on utility scores, hand surgeons feel that living with a painful, poorly functioning RA wrist for 30 years is worth approximately half as many years with a painless, well-functioning wrist. The outcomes for arthroplasty and arthrodesis are valued more than nonsurgical management. On the basis of its higher expected gain in QALYs, arthroplasty should be the preferred treatment. The minimal increase in utility for arthroplasty over arthrodesis suggests however, that surgeons do not view arthroplasty as superior to arthrodesis.

TYPE OF STUDY/LEVEL OF EVIDENCE

Economic and decision analysis IV.

[Research and surgery]

From the Second World War onwards an amazing development in science and clinical & surgery practice has taken place: antibiotics, blood storage, cardiac surgery, organ and tissue transplant, complete joint replacement, total intravenous nutrition or minimally invasive surgery. Paradoxically, during the last two decades of the XXth century, social popularity of doctors has decreased at the same time of some important changes: increases in costs of medical attention, trials against medical mistakes, some doubts on the real role of Academic Public Hospitals and rising in the importance of alternative medicine. Increasing complexity of biomedical research in the continuous changing age of molecular biology has promoted an increasing scepticism regarding clinics and surgeons are able to keep on contributing to medical advances. The study of the contemporaneous History of Medicine demonstrates that some of the more significant achievements have been accomplished by surgeons. Undoubtedly Science and Clinics must get adapted to these times of change and persist in generating important findings. Current Clinical and surgical practice is completely determined by yesterdays' scientific research; tomorrow won't be different.

The surgical treatment of cubital tunnel syndrome: a decision analysis

The objective of our study was to use decision analysis to compare four common surgical treatments for cubital tunnel syndrome: simple decompression of the cubital tunnel, medial epicondylectomy, anterior subcutaneous transposition and anterior submuscular transposition. The variables used for this decision analysis model were based on data from the literature. Extensive sensitivity analyses were carried out to test the impact of the values given to these variables on the outcome of the model. The highest expected utility, 0.973, was associated with simple decompression. The expected utility was 0.969 for subcutaneous transposition and 0.965 for submuscular transposition. Medial epicondylectomy had the lowest expected utility at 0.961. Simple decompression remained the preferred strategy in extensive one-way sensitivity analyses.

Use of colonic stents in emergent malignant left colonic obstruction: a Markov chain Monte Carlo decision analysis

PURPOSE

This decision analysis examines the cost-effectiveness of colonic stenting as a bridge to surgery vs. surgery alone in the management of emergent, malignant left colonic obstruction.

METHODS

We used a Markov chain Monte Carlo decision analysis model to determine the effect on health-related quality of life of two strategies: emergency surgery vs. emergency colonic stenting as a bridge to definitive surgery. All relevant health states were modeled during a patient's expected lifespan. Outcome measures were mortality, the proportion of patients requiring a colostomy, quality-adjusted life expectancy, and costs. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

In our model, colonic stenting was more effective (9.2 quality-adjusted life months benefit) and less costly (CAD dollars 3,763; US dollars 3,135) than emergency surgery. Its benefits were secondary to reductions in acute mortality and in the likelihood of requiring a permanent colostomy. The results were only dependent on the rate of stenting complications (perforation, technical placement failure, and migration) and the patient's risk of surgical mortality, with the benefits being greatest among patients at high risk of operative mortality.

CONCLUSIONS

Colonic stenting as a bridge to surgery is more effective and less costly than surgery in the treatment of emergent, malignant left colonic obstruction. The benefits are most pronounced in high-risk patients and are diminished by increases in stent placement failure rates and perforation rates. In low-risk patients, the benefits are more modest and may not outweigh the risks.

Strategies for nonrandomized clinical research in hand surgery

Most clinical research questions in hand surgery may be effectively explored using a variety of nonrandomized study designs. The main advantage of any of these methods is that they are almost always more feasible than a prospective randomized, controlled trial. Although the level of evidence associated with nonrandomized designs is always lower than that of a randomized trial there are many instances in which the inferences based on these designs are sufficiently strong that important and meaningful conclusions can be made. The key considerations in using nonrandomized designs are to frame the research question appropriately and to recognize and anticipate the limitations and biases that are inherent to each one of these approaches.

The cost-effectiveness of cefepime plus metronidazole versus imipenem/cilastatin in the treatment of complicated intra-abdominal infection

BACKGROUND

Our objective was to compare the economic benefits of cefepime plus metronidazole with those of imipenem/cilastatin in the treatment of complicated intra-abdominal infections.

METHODS

We used a retrospective analysis of clinical outcomes and health resource utilization data collected during a randomized, double-blind, multi-center clinical trial. Seventeen university-affiliated hospitals in the United States and Canada participated, as did 323 patients with complicated intra-abdominal infections. Decision analysis was conducted using a decision node of cefepime vs. imipenem, and chance nodes that included an Acute Physiology and Chronic Health Evaluation (APACHE) II score of #15 versus .15; a need for posttreatment surgical procedures; and clinical outcomes. Effectiveness of treatment was measured by differences in the length and cost of hospital stays, the number and cost of surgical procedures after treatment, cure rates, and the cost of antibiotics. Also evalulated were the incremental costs of cure (i.e., the costs of additional cures).

RESULTS

Comparing cefepime plus metronidazole with imipenem/cilastatin, the expected cost of patient care was $8,218 versus $10,414, respectively, and the cost-effectiveness ratio per cure was $10,058 versus $13,685. For severely ill patients (APACHE II score .15), the expected cost was $12,962 versus $23,153, and the cost-effectiveness ratio per cure was $15,321 versus $64,313.

CONCLUSIONS

Cefepime plus metronidazole was more cost-effective than imipenem/cilastatin in the treatment of complicated intra-abdominal infections, primarily because of fewer post-treatment surgical procedures and shorter hospital stays. The primary advantage accrued to severely ill patients who had an APACHE II score .15.

Cervical spine evaluation in urban trauma centers: Lowering institutional costs and complications through helical CT scan1

BACKGROUND

In the evaluation of the cervical spine (c-spine), helical CT scan has higher sensitivity and specificity than plain radiographs in the moderate- and high-risk trauma population, but is more costly. We hypothesize that institutional costs associated with missed injuries make helical CT scan the least costly approach.

STUDY DESIGN

A cost-minimization study was performed using decision analysis examining helical CT scan versus radiographic evaluation of the c-spine. Parameter estimates were obtained from the literature for probability of c-spine injury, probability of paralysis after missed injury, plain film sensitivity and specificity, CT scan sensitivity and specificity, and settlement cost of missed injuries resulting in paralysis. Institutional costs of CT scan and plain radiography were used. Sensitivity analyses tested robustness of strategy preference, accounted for parameter variability, and determined threshold values for individual parameters on strategy preference.

RESULTS

C-spine evaluation with helical CT scan has an expected cost of US 554 dollars per patient compared with US 2,142 dollars for plain films. CT scan is the least costly alternative if threshold values exceed US 58,180 dollars for institutional settlement costs, 0.9% for probability of c-spine fracture, and 1.7% for probability of paralysis. Plain films are least costly if CT scan costs surpass US 1,918 dollars or plain film sensitivity exceeds 90%.

CONCLUSIONS

Helical CT scan is the preferred initial screening test for detection of cervical spine fractures among moderate- to high-risk patients seen in urban trauma centers, reducing the incidence of paralysis resulting from false-negative imaging studies and institutional costs, when settlement costs are taken into account.

Decision analysis in orthopaedics

Orthopaedic surgeons are faced with an ever-growing amount of clinical information from which they are required to make treatment decisions. Many of these decisions can be approached with relative certainty. However, there are many situations where the optimal decision is less clear. These treatment decisions will have competing risks, benefits, or costs. Decision analysis is one method to critically evaluate alternative treatment options with multiple potential outcomes. This method of decision making can be extremely valuable because of the growing number of treatment alternatives, and to the ever-increasing complexity of medical scenarios.

Management of the second episode of spontaneous pneumothorax: a decision analysis

BACKGROUND

Optimal management for patients presenting a second episode of spontaneous pneumothorax remains controversial. The aim of this study was to compare two possible treatment strategies, video-assisted thoracic surgery (VATS) and conservative management, in order to assess which of the two was better adapted for the treatment of the second episode of spontaneous pneumothorax.

METHODS

The authors propose a decision analytic model including a cost-effectiveness study to compare two clinical strategies: VATS (reference strategy) and conservative management (alternative strategy). Data were obtained from a Medline search for English language articles and cost estimates were derived from the financial and public health departments of our hospital. The model was analyzed to determine the baseline strategy leading to the highest expected effectiveness and the lowest expected cost.

RESULTS

Conservative management offered a slight advantage in expected effectiveness value (99.99 vs 99.93 for VATS). VATS produced the lowest expected cost (4347 vs 7536 for conservative management). The incremental cost-effectiveness ratio was 57,750. Within the ranges tested, the sensitivity analysis presented consistent results in terms of effectiveness and advocated conservative management as the best strategy. In terms of cost, with the exception of length of stay, the sensitivity analysis was insensitive in estimating the different probabilities, and favored VATS over conservative management.

CONCLUSIONS

In the management of the second episode of spontaneous pneumothorax, VATS offers substantial savings in cost for only a slight decrease in effectiveness, when compared with conservative management.

Operative versus nonoperative management of acute Achilles tendon rupture: expected-value decision analysis

BACKGROUND

The optimal management strategy for acute Achilles tendon rupture is controversial.

PURPOSE

To determine the optimal management by using expected-value decision analysis.

STUDY DESIGN

Cross-sectional study.

METHODS

Outcome probabilities were determined from a systematic literature review, and patient-derived utility values were obtained from a visual analog scale questionnaire. A decision tree was constructed, and fold-back analysis was used to determine optimal treatment. Sensitivity analyses were used to determine the effect of varying outcome probabilities and utilities on decision-making.

RESULTS

Outcome probabilities (expressed as operative; nonoperative) were as follows: well (0.762; 0.846), rerupture (0.022; 0.121), major complication (0.030; 0.025), moderate complication (0.075; 0.003), and mild complication (0.111; 0.005). Outcome utility values were well operative (7.9), well nonoperative (7.0), rerupture (2.6), major complication (1.0), moderate complication (3.5), and mild complication (4.7). Fold-back analysis revealed operative treatment as the optimal management strategy (6.89 versus 6.30). Threshold values were determined for the probability of a moderate complication from operative treatment (0.21) and the utility of rerupture (6.8).

CONCLUSIONS

Operative management was the optimal strategy, given the outcome probabilities and patient utilities we studied. Nonoperative management was favored by increasing rates of operative complications; operative, by decreasing utility of rerupture. We advocate a model of doctor-patient shared decision-making in which both outcome probabilities and patient preferences are considered.

A prospective evaluation of patients undergoing surgery for the palliation of an advanced malignancy

BACKGROUND

Decisions regarding the use of surgical procedures for the palliation of symptoms caused by advanced malignancies require the highest level of surgical judgment. Prospective analysis of palliative surgical care may facilitate a more effective and representative evaluation of these patients.

METHODS

Patients requiring surgery planned solely for the palliation of an advanced malignancy were offered entry onto this study. Outcome measurements were made before surgery and monthly thereafter until the patient's death. Accepted techniques of pain assessment, quality of life, and functional status were used.

RESULTS

Between May 1997 and December 1999, 26 patients were enrolled. Although 46% (12 of 26) of patients demonstrated improvement in pain control or quality of life after palliative surgery, these benefits lasted a median of only 3.4 months. Palliative surgery was associated with significant postoperative complications in 35% (9 of 26) patients.

CONCLUSIONS

Although many patients had no apparent demonstrable benefit from surgery, surgeons were able to identify a group of patients who experienced significant benefits after a palliative procedure. The relationships between the patient and family members and the surgeon play an important role in decision-making throughout the palliative phase of cancer treatment.

Decision analysis for small, asymptomatic intracranial arteriovenous malformations

Object

Asymptomatic intracranial arteriovenous malformations (AVMs) represent a clinically challenging problem because of the complex decision making that must be undertaken prior to beginning any type of treatment. In addition, the relative infrequency of these lesions means that there is relatively little experience reported in the literature. The authors use a decision-analysis technique to model the considerations that go into determining the treatment of these lesions in an effort to quantify the various risks and overall benefits conferred by the following three treatment strategies: observation/natural history, microsurgery, and stereotactic radiosurgery.

Methods

The authors conducted a thorough literature search to elucidate the risks and outcomes associated with each treatment option. These values were used to build and run a comprehensive Markov model to determine a base-case analysis. All of the input variables were also subjected to sensitivity analysis to identify the most influential input variables and the crossover points in which favored strategies changed.

The base-case analysis suggested that microsurgery was the favored treatment option because this hypothetical cohort accumulated 21.53 quality-adjusted life years (QALYs) over the course of the model compared with the 16.97 QALYs and 16.40 QALYs for stereotctic radiosurgery and observation, respectively. Sensitivity analysis demonstrated that overall major neurological morbidity and mortality were the most influential input variables both perioperatively and during the radiosurgical “latent” period (that is, up to 2 years posttreatment). The maximum acceptable perioperative combined major neurological morbidity and mortality rate was 6.8%. The latent period combined major neurological morbidity and mortality would need to be 0.7% to make radiosurgery favorable in this analysis.

Conclusions

Results of this decision analysis model suggest that microsurgery in the hands of experienced cerebrovascular surgeons, who can expect a less than 6.8% combined rate of major neurological morbidity and mortality, offers patients a greater overall quality of life over time.

An economic evaluation of sonographic examination of children with suspected appendicitis

BACKGROUND/PURPOSE

Appendicitis is the most common surgical emergency presenting in the pediatric population. Approximately one third of these patients present with equivocal signs and symptoms frequently resulting in inpatient observation or additional diagnostic investigation. Although sonographic examination of patients with suspected appendicitis has been shown to be a highly accurate diagnostic modality, the cost effectiveness of this technology in the pediatric population has not been addressed. The economic value of this examination can be evaluated using a structured decision analysis.

METHODS

The authors constructed a decision analysis model of treatment strategies for 2 groups of patients with a suspected diagnosis of acute appendicitis. Patients were categorized as either presenting with a "definitive acute abdomen" or "equivocal examination." Data drawn from published literature reports of the sensitivity and specificity of ultrasound, institution-specific cost data, and expert judgment were used to construct 2 decision trees. These data were used to determine the least costly diagnostic strategy for each group of patients, and sensitivity analysis performed to assess the robustness of the conclusions.

RESULTS

The use of ultrasonography in patients with "an acute abdomen" is not cost efficient and results in average additional cost of $234 per patient. In patients with equivocal diagnoses who are discharged from the emergency room after a negative ultrasound examination finding results in an average cost savings of $260 when compared with admission and observation. Patients who are discharged without examination incur an average additional cost of $373 as a result of the high cost of a missed diagnosis resulting in a perforated appendix.

CONCLUSION

The use of ultrasonography can be recommended for children with suspected appendicitis and equivocal examinations who are discharged from the emergency room after a negative examination result.

Decision making on surgical palliation based on patient outcome data

BACKGROUND

Strategies for the effective application of palliative procedures are infrequently standardized and incompletely understood. The effect on patient outcome as determined by elements such as resolution of chief complaints, quality of life, pain control, morbidity of therapy, and resource utilization should predominate decisions regarding surgical palliative care.

METHODS

Articles published between 1990 and 1996 on the surgical palliation of cancer were identified by a MEDLINE search and reviewed for designated parameters considered important for good palliative care.

RESULTS

A total of 348 citations were included. Entries considered these fundamental elements: cost (2%); pain control (12%); quality of life (17%); need to repeat the intervention (59%); morbidity and mortality (61 %); survival (64%); and physiologic response (69%). Established methods for quality of life and pain assessment were sporadically utilized.

CONCLUSIONS

In the current surgical literature, there is uncommon reporting of the range of data required to recommend sound palliative surgical choices.