Outcomes of Same-Day Orthopedic Surgery: Are Spine Patients More Likely to Have Optimal Immediate Recovery From Outpatient Procedures?

INTRODUCTION

It is estimated that the incidence of spinal pathologies, such as degenerative disc disease, is on the rise in the United States, with a proportional increase in the number of procedures being performed.^1,2 In recent decades, the number of lumbar procedures has more than doubled, with a similar surge seen in the number of cervical procedures being performed.^3–5 These figures are of concern, as the disparity in healthcare expenditures continues to overwhelm hospital systems. Furthermore, with a shift in reimbursements toward bundle payments in the United States, there is further pressure on hospitals and surgeons to further reduce healthcare expenditures.⁶

There has been much research into improving patient outcomes with the use of various methodologies, such as preoperative patient optimization, developing risk prediction models, and mitigating anticipated complications postoperatively.^7–11 The synergistic effect of these modalities is an attempt to reduce patient morbidity and mortality as well as to reduce healthcare costs. An additional method of controlling costs is to transition from inpatient to outpatient procedures to reduce the high costs of hospital bed per day as well as supplies.¹² The development of protocols for transitioning from outpatient to inpatient orthopedic procedures has seen tremendous success for various orthopedic procedures, such as total joint arthroplasty.^13–18 These studies have found ambulatory surgery to be safe and effective and may potentially result in a reduction of nosocomial complications when compared to inpatient procedures.

Similarly, there has been a trend toward outpatient spinal procedures, many of which show it to be a feasible option to offset hospital costs without compromising patient safety.^19–22 There is generally an inherently higher risk profile in patients undergoing spinal procedures when compared to other divisions of orthopedic surgeries.²³ Although there has been much research comparing the safety and efficacy of inpatient versus outpatient spinal procedures, there is very limited (if any) literature comparing the outcomes of this transition to additional orthopedic procedures. Therefore, the purpose of this study was to assess outcomes and improvements in spinal inpatient and outpatient surgery when compared to other orthopedic procedures.

METHODS

RESULTS

DISCUSSION

There has been a marked increase in the number of spine procedures being performed in the United States as well as worldwide, which is estimated to have more than doubled in the previous decades.^{3–5,24–26} Additionally, there has been a concomitant net increase in healthcare costs for these procedures, with estimates of over $35 billion from 2001 to 2010 in the United States.^27,28 One method of reducing this expenditure would be to remove the most obviously exorbitant cost of an inpatient hospital bed, which is estimated to be over $5000 per day, and performing procedures on an outpatient basis.¹² As a transition takes place toward ambulatory cervical and lumbar procedures, it is important to understand their safety when compared to inpatient procedures as well as in comparison to other orthopedic procedures.^29–31 Our study found that spine procedures were associated with higher complications in the inpatient setting and lower complications in outpatient cases when compared to other orthopedic procedures.

Although there are no level I or II studies assessing the safety of inpatient versus outpatient spine procedures, there has been some literature demonstrating it to be a safe medium for surgery.^{13,15–18,20,21,32,33} A systematic review of 56 articles evaluating ambulatory spine surgery found that a majority of studies reported no differences in peri- and postoperative complications, readmissions, and reoperations when compared to inpatient cases.^19,33,34 These findings indicate that outpatient spine cases may be a safe alternative to the traditional inpatient cases. Furthermore, a meta-analysis of studies evaluating cervical and lumbar spine surgeries, with a total of 370,195 patients, demonstrated that outpatient procedures had significantly lower overall costs when compared to inpatient procedures.²² When substratified by age, the study showed that costs for younger patients were markedly lower than procedures for older patients ($555 vs $7290, respectively). This discrepancy in costs is likely attributed to generally higher comorbidity and therefore risk in older patients undergoing surgery.³⁵

Similar trends have been observed in other outpatient orthopedic procedures when compared to inpatient procedures, which showed similar postoperative complications and lower overall costs. A study by Darrith et al¹⁶ evaluated 243 consecutive patients undergoing outpatient arthroplasty procedures and compared them to a matched cohort undergoing inpatient arthroplasty and tracked them for 90 days. The authors effectively demonstrated no significant differences when comparing readmission rates, major and minor complications, reoperations, emergency room visits, and unplanned clinic visits between the 2 cohorts.

However, some studies have even showed better overall outcomes of outpatient procedures when compared to inpatient cases. For example, a study by Huntley et al³⁶ reviewed 7672 patients undergoing foot and ankle surgery using the ACS-NSQIP database. When compared to outpatient cases, the authors found that patients undergoing inpatient procedures had significantly higher surgical (8.6% vs 2.0%) and medical complications (16.9% vs 1.7%). These findings appear promising for surgeons considering outpatient procedures as a safe alternative to inpatient cases; however, additional findings in this study highlight the importance of underlying patient demographics and comorbidities as the true deciding components of overall outcomes. Unsurprisingly, the inpatient group represented a higher-risk population when compared to the outpatient group, with a higher mean age, more smokers, poorer functional status, and, most important, a disproportionately higher prevalence of every comorbidity. This is similar to the findings of our study, as patients who had higher comorbidities, which occur often in the spine patient population, had more complications when compared to other orthopedic procedures. This strongly suggests the role and importance of careful patient selection when considering outpatient procedures as well as a potentially existing bias inherent in current studies evaluating these 2 modalities.

There were some limitations in our study, particularly the retrospective nature. Furthermore, there are several inherent known limitations with the use of the NSQIP database, with a reliance on the accuracy of ICD-9 and CPT codes to identify patient outcomes.³⁷ There may have been coding inconsistencies that potentially resulted in an under- or overrepresentation of effects and outcomes. Additionally, as many complications and reoperations can occur for up to 1 year from the index procedure, many of these may be missed since the database allows patient tracking for only 30 days postoperatively. In spite of some of these limitations, we feel that the use of a large database allows us to have adequate power to potentially overcome biases and coding errors to effectively assess the main question of our study.

The pressures to transition from inpatient to outpatient spine procedures appear to be multifactorial, influenced also by changes in reimbursement as bundled payment models.⁶ Furthermore, as the Centers for Medicare and Medicaid Services transitions from inpatient-only procedures to outpatient, insurance companies are also denying preauthorization for inpatient stays following surgery, which may translate to spine surgeries.³² As outpatient procedures may be riskier due to less postoperative observation, the advent of additional patient optimization strategies and selection is ever important. Additionally, the use of ambulatory procedures has resulted in the development and refinement of minimally invasive techniques in an attempt to further mitigate and reduce complications.^29,38

CONCLUSIONS

The results of our study found that inpatient spine surgery patients had higher complications than outpatient when compared to other orthopedic cases. It is possible that inpatient procedures carry with them an inherent sense of safety and comfort with constant medical observation, possibly resulting in less attention to minute patient risk factors and therefore operating on higher-risk patients, which is in contrast to outpatient procedures potentially requiring a more careful evaluation, more aggressive intervention, and improved risk mitigation. Further studies are needed not only to normalize outcomes within a surgical specialty but also to explore variations in subspecialty patient risks as an important means of understanding the multifactorial components contributing to patient complications and hospital costs following any orthopedic procedure, both inpatient and outpatient.