An Evaluation of Patient Risk Factors to Determine Eligibility to Undergo Orthopaedic Surgery in a Freestanding Ambulatory Center A Survey of 4,242 Consecutive Patients.

INTRODUCTION

The value proposition of surgery at freestanding ambulatory surgery centers (FSASCs) in terms of efficiency, safety, and patient satisfaction is well established and has led to increased FSASC utilization. However, there are comorbid conditions that disqualify certain patients from surgery at FSASCs. Understanding the percentage of patients whose comorbid conditions exclude them from FSASCs is important for the proper planning and utilization of operating room assets. We aim to understand the percentage of excluded patients, and we predict that certain procedures have higher rates of disqualification due to the types of patients who undergo them.

METHODS

We reviewed the records of 4,242 consecutive patients undergoing outpatient orthopaedic surgeries in our hospital system from July 2015 to February 2016. Patient characteristics, comorbidities, and procedures performed were included in our database. We analyzed each case and determined eligibility for surgery at our FSASC based on established comorbidity exclusionary guidelines. Chi-square and t-tests were used to establish statistical significance.

RESULTS

Of 4,242 patients, 878 (20.7%) were ineligible for surgery at our FSASC based on accepted exclusionary guidelines. The average body mass index (BMI) of FSASC-eligible patients was 27.37, compared to 31.68 for FSASC-ineligible patients (p < 0.001). The majority, 85.6% (543/634), of American Society of Anesthesiologists (ASA) class 3 patients were FSASC-ineligible. The most common reasons for excluding patients from surgery at our FSASC were morbid obesity (25.4% of ineligible cases), untreated obstructive sleep apnea (22.1%), age less than 13 (19.6%), and coronary artery disease with prior intervention (13.3%). When stratifying by procedure, the operations most likely to be FSASC-ineligible were contracture releases (39.13% ineligible, p = 0.03), trigger finger releases (36.14%, p < 0.001), carpal tunnel releases (30.63%, p = 0.009), tumor resections (38.89%, p = 0.056), rotator cuff repairs (25.47%, p = 0.078), and subacromial decompressions (30.23%, p = 0.12), primarily because these patients have more comorbidity (ASA 2.20 vs. 1.88, p < 0.001).

CONCLUSIONS

Roughly 1 in 5 patients is ineligible for surgery at a freestanding ASC due to disqualifying comorbidities. Although FSASCs offer cost effective care that satisfies patients, we must understand that certain patients cannot have their surgeries at these venues. In addition, we must use additional caution when scheduling certain procedures at a FSASC. Therefore, as the number and complexity of the surgeries performed at FSASCs increase, we must better understand the factors that make patients better candidates for surgery in a hospital setting, thus minimizing transfers and readmissions and maximizing the value proposition of FSASCs.