Abstract
Introduction
Posterior spinal fusion (PSF) is the gold standard procedure for curve correction in Adolescent Idiopathic Scoliosis (AIS). Enhanced recovery protocols (ERPs) have been found to decrease pain and hospital length of stay (LOS) resulting in decreased total hospital charges.
Methods
We identified all adolescent idiopathic scoliosis patients treated with a posterior spinal fusion at our children’s hospital between 2015–2019. Length of stay, pain scores, and hospital direct costs were calculated to determine the pathway’s efficacy.
Results
Hospital LOS was reduced by 26% and post-op pain scores did not significantly change when using the Team Integrated Enhanced Recovery (TIGER) protocol (P<0.05). Total hospital costs decreased by 7.9%, daily contribution margins increased 7.9%, and daily net income increased 10.6% after TIGER protocol implementation.
Conclusion
TIGER protocol resulted in decreased hospital LOS as well as direct costs for the hospital without increasing postoperative pain scores.
Introduction
Enhanced recovery protocols (ERP) for patients undergoing posterior spinal fusion to treat adolescent idiopathic scoliosis (AIS) have become more widespread. Muhly et al.1 was the first to demonstrate that enhanced protocols can reduce hospital length of stay (LOS) without increasing pain scores or readmission rates. ERPs rely on several avenues to enhance recovery after surgery. These include: 1) admission directly to the surgical floor rather than an intensive care unit (ICU); 2) rapid mobilization; 3) transition to a multimodal pain regimen with early weaning of patient-controlled analgesia (PCA); and 4) minimizing drains, intravenous fluid lines, and dressings.
ERPs have been shown to be effective at large pediatric spine centers in reducing hospital LOS between 31% to 48%,2,3 and have also improved inpatient procedure costs by as much as 22%.4 Further, Boylan et al. analyzed the New York Statewide Planning and Research Cooperative System database and determined each additional postoperative day in the hospital after posterior spinal fusion (PSF) for AIS was associated with an additional $5,198 in hospital costs, a 28% increased risk of 90-day readmission, and a 57% increased risk of returning to the operative suite within 90 days.5 Although most previous literature has looked at direct cost savings to the hospital, we were interested in the contribution margin (total revenue of the procedure minus the direct costs of the procedure and inpatient admission) as this may give a more accurate assessment of the true impact the enhanced recovery protocol has on early discharge.
The foundation of an ERP is centered on improving patient care, but it is also economically advantageous. However, the generalizability and sustainability of implementation of an ERP is unclear. Previous ERPs have been primarily implemented at large pediatric spine centers with multiple pediatric spine surgeons and nurses accustomed to caring for AIS patients who undergo PSF. We therefore sought to determine if these protocols were generalizable to a single center with one pediatric spine surgeon. We followed the model outlined by Muhly et al.1 to implement a quality improvement (QI) project focused on improving patient care and decreasing health care expenditure by instituting our own ERP, referred to as the Team Integrated Enhanced Recovery (TIGER) Protocol. We hypothesized that the implementation of the TIGER protocol would result in similar postoperative pain scores and a decreased hospital LOS, resulting in an increase in the contribution margin to our health care system for each patient treated with a posterior spinal fusion.
Methods
Quality Improvement (QI)
Prior to implementation of the TIGER Protocol, there was no standardized preoperative counseling for either the patient or their parents focused on post-operative expectations. Additionally: 1) dexmedetomidine was administered preoperatively as an anxiolytic requiring a post-operative stay in the pediatric intensive care unit (PICU); 2) a superficial and deep hemovac were placed during surgery; 3) physical therapy was started on postoperative day 1 and worked with patients only once per day; 4) post-operative analgesia was patient dependent with PCA administered until postoperative day three; and 5) a foley catheter was maintained until postoperative day two.
The first step in implementing the TIGER Protocol included: 1) optimization of pain management with the help of anesthesia and the pharmacy; 2) standardized physical therapy with mobilization of the patient at the side of the bed the evening of surgery; 3) engagement with therapy twice per day; 4) specialized nurses who managed all AIS patients; and 5) a nurse practitioner (NP) who managed all postoperative order sets and postoperative rounding (Figure 1). Perhaps the most important aspect, which we believe cannot be overstated, is having a NP or physician’s assistant take ownership of this pathway to allow for continuity of care, including scheduling the same group of nurses for postoperative care. This allows for systemic buy-in from the nurses who can easily contact the same person daily with any questions regarding the post-operative protocol. This minimizes deviations from the protocol and allows for the sustainability of this model.
Figure 1.
Pathway for the Team Integrated Enhanced Recovery (TIGER) protocol
Although previously discussed, we believe the crux of pain management is inclusion of a regimen relying on different types of pain relief to reduce narcotic usage. Due to the high levels of evidence for the efficacy of local anesthesia, acetaminophen, and gabapentin to reduce pain and diminish narcotic usage, these are integral components of our post-operative pain protocol. Further, although the evidence is more limited, ketorolac is administered prior to the patient leaving the OR and then administered every 8 hours until the patient is discharged, or pain is minimal. Diazepam is also administered as needed to reduce muscle spasms.6 A morphine PCA is still available for each patient, but this is limited to the first post-operative night. The effectiveness of this approach hinges on each of these medications employing a different mechanism of reducing pain.
After our NP, nursing staff, physical therapists, pharmacy, lab, and radiology technicians all felt engaged and took ownership of this ERP, we were able to achieve the following: 1) detailed patient and parent preoperative expectations; 2) improvement and acceleration of the recovery pathway by standardizing patient analgesia; 3) expedited foley catheter removal; and 4) aggressive bowel therapy (Figure 1). Once the TIGER Protocol was implemented, we continued to have biannual educational training with nursing and physical therapy staff to reinforce it.
Inclusion Criteria
All patients undergoing PSF for AIS at the University of Missouri between January 1, 2015 and December 17, 2019 were eligible for inclusion into this retrospective analysis. Any patient who underwent PSF for any diagnosis other than AIS was excluded. Our ERP (TIGER protocol) was implemented on October 31, 2016. Patients treated between January 1, 2015 to October 31, 2016 were categorized as Standard Protocol (SP) and those treated on or after November 1, 2016 were categorized as ERP. A total of 92 patients met the inclusion criteria. Retrospective review of their electronic medical record and imaging included age, sex, number of levels fused, average pain scores on postoperative day 0–4, hospital LOS, postoperative complications, and readmission rates or emergency department visits.
Healthcare Costs
All financial data was provided through our billing department, including patient insurance type, daily contribution margin, direct costs, and total costs. The data was analyzed by the billing department to determine the contribution margin of the ERP compared to the SP pathway. To have a similar number of patients in the TIGER and SP groups, only the first 26 patients in the TIGER protocol were considered for inclusion for evaluation of billing data. Further, after pooling both protocols together the contribution margin was calculated depending on patient insurance type.
Statistics
A two-tailed, unpaired, student t-test was used to evaluate the demographics, LOS, and pain scores between the TIGER and SP cohorts. Sustainability of the TIGER protocol, as determined both by LOS and pain scores on days 0–4, was calculated using an analysis of variance (ANOVA). Due to the decreased hospital LOS achieved by 2019, only two TIGER protocol patients remained hospitalized on postoperative day 4. A student t-test was used to determine if a difference existed between pain scores in 2017 and 2018. Statistical significance was set at P < 0.05 for all analyses.
Results
The demographics of the SP and TIGER pathway were not significantly different either in age or sex (P > 0.05). Both the SP and TIGER cohorts were overwhelmingly female. The number of levels fused in patients treated with the TIGER cohort was fewer than when compared with the SP group (Table 1). Importantly, when comparing the SP and ERP groups there was no significant difference in complication rate, readmissions, or emergency department visits (P < 0.05). There was also a significantly shorter LOS and PICU stay between the two cohorts. The SP group required 1.7 +/− 0.8 days in the PICU and a total hospital LOS of 4.7 +/− 1.0 days. The SP cohort had a significantly longer LOS than the TIGER pathway requiring a total hospital stay of 3.5 +/− 1.3 days (P < 0.001) (Table 2). The breakdown in LOS of the TIGER cohort was as follows: 10% of the TIGER pathway went home on day 2, 54% discharged on day 3, 24% discharged on day 4, 3% discharged on day 5, and the remaining 9% discharged after day 5 (Figure 2). Three TIGER protocol patients did require a short stay in the PICU. Two were due to intraoperative neuromonitoring changes, which resulted in no postoperative neurologic deficits. One patient had a headache raising concern for a possible dural tear. After five days of slow symptomatic improvement, the patient’s headache completely resolved, and the patient was returned to floor status. Otherwise, no TIGER protocol patient was admitted to the PICU.
Table 1.
- SP = standard protocol
- TIGER = Team Integrated Enhanced Recovery protocol.
| SP | TIGER | P value | |
|---|---|---|---|
| Number of patients | 22 | 70 | |
| Age (yrs.) | 15 ±2.3 | 14.9 ±1.8 | 0.9 |
| Sex (% female) | 77 | 73 | 0.7 |
| Fusion length | 11.7 ± 1.5 | 9.7 ± 2.6 | < 0.001 |
Table 2.
- SP = standard protocol
- TIGER = Team Integrated Enhanced Recovery protocol
- PICU = pediatric intensive care unit
- ED = emergency department
| SP | TIGER | P value | |
|---|---|---|---|
| Length of PICU | 1.7 ± 0.8 | 0.1 ±0.1 | <0.001 |
| Inpatient length of stay | 4.7 ± 1.0 | 3.5 ± 1.3 | <0.001 |
| ED visits | 1 | 1 | 0.4 |
| Complications/revisions | 0 | 2 | 0.4 |
| readmissions | 0 | 0 | 1.00 |
Figure 2.
Length of stay (LOS) for floor and pediatric intensive care units after TIGER protocol implementation (2015–2019).
The TIGER protocol focuses on early weaning of PCA without a basil rate and a more aggressive physical therapy regimen. To determine if this caused any increase in pain, we recorded patient reported pain scores during postoperative days 0–4. We observed no difference in the SP or ERP pathways regarding pain scores on any postoperative day (P > 0.05). We also wanted to determine the sustainability of the TIGER protocol on a yearly basis from 2017 to 2019. We found no difference in pain scores or hospital LOS between any of the years after implementation of the TIGER protocol (Table 3). However, shorter hospital LOS did trend toward significance in 2019 compared to 2017 and 2018 (P = 0.07).
Table 3.
- TIGER = Team Integrated Enhanced Recovery protocol
- LOS = length of stay
- ANOVA = analysis of variance
| 2017 | 2018 | 2019 | P value | |
|---|---|---|---|---|
| Length of inpatient stay | 3.7 ± 1.0 | 3.7 ± 1.8 | 3.0 ± 0.7 | 0.07 |
| Pain postoperative day 0 | 3.6 ± 1.3 | 3.3 ± 1.8 | 2.7 ± 1.6 | 0.14 |
| Pain postoperative day 1 | 3.5 ± 1.3 | 3.1 ± 1.7 | 2.9 ± 1.6 | 0.4 |
| Pain postoperative day 2 | 3.7 ± 1.3 | 3.1 ±1.7 | 3.0 ± 2.2 | 0.4 |
| Pain postoperative day 3 | 3.5 ±1.6 | 2.5 ±1.4 | 3.1 ±2.6 | 0.2 |
| Pain postoperative day 4 | 3.7 ± 2.0 | 2.5 ± 1.3 | 0.2 |
Finally, with assistance from the billing department we were able to analyze all financial data from patients undergoing PSF for AIS between January 2015 to February 2018, including all 22 SP patients and the first 26 TIGER protocol patients. The average direct cost of AIS correction in the SP cohort was $41,630.80 compared to $40,543.05 in the TIGER cohort resulting in a 2.6% cost reduction. Importantly, the average daily contribution margin was $15,127.73 in the SP group compared to $16, 328.16 in the TIGER protocol group. This led to a 7.9% increase in the contribution margin for the TIGER protocol group. Finally, the total inpatient cost for the SP cohort was $63,46.44 compared to $58,452.27 in the TIGER cohort for a 7.9% cost savings (Table 4). When analyzing the total contribution margin between the TIGER protocol and SP cohorts, many contribution margins were in the range of $50,000 to $100,000. When broken down into contribution margins based on insurance type, regardless of protocol used, Medicaid was the only insurance that resulted in a negative contribution margin in 5 of the 48 patients. All remaining private insurances resulted in positive contribution margins with 28 of the 48 patients having a contribution margin between $50,000 to $100,000.
Table 4.
- SP = standard protocol
- TIGER = Team Integrated Enhanced Recovery protocol
| SP pathway N = 22 |
TIGER pathway N = 26 |
% change | |
|---|---|---|---|
| Direct cost | $41,630.80 | $40,543.05 | −2.6 |
| Contribution margin | $67,033.76 | $58,929.95 | −12.1 |
| Daily contribution margin | $15,127.73 | $16,328.16 | 7.9 |
| Total cost | $63,476.44 | $58,452.27 | −7.9 |
| Net income | $45,188.11 | $41,020.74 | −9.2 |
| Daily net income | $10,312.87 | $11,407.60 | 10.6 |
Discussion
The aim of our QI project was to maximize patient care and decrease total costs in patients with AIS undergoing posterior spinal fusion. Consistent with our hypothesis, LOS was decreased by 26% after implementation of TIGER protocol with no increase in postoperative pain. The 26% LOS reduction resulted in a total cost savings of 7.9%. Further, there was an increase of 7.9% to our daily contribution margin and a 10.6% increase of our daily net income after TIGER protocol implementation. Although our LOS did not approach the 2.2 days and 48% decrease found by one multi-center study,3 it was like the 31% decrease in LOS found after implementation of an ERP by other institutions.7–9 Additionally, our 7.9% total cost savings are consistent with the 9% cost savings found by Raudenbush et al.9 after implementation of an ERP. Although they found minor savings using an ERP, they maximized cost savings when minimizing pedicle screws per level and bone graft.
When further analyzing hospital costs after implementation of the TIGER protocol, Medicaid insurance continued to result in a negative contribution margin even after protocol initiation; two TIGER protocol patients and all three SP patients had negative contribution margins with Medicaid insurance. Additional measures to minimize costs in scoliosis patients should be considered including the use of a low-density pedicle screw construct design when appropriate. This has previously been demonstrated to significantly decrease implant costs, operating time, and blood loss.10
While results regarding decreased hospital LOS and healthcare costs have previously been identified, the sustainability of the ERP over consecutive years is less clear.1–5,7 We found the TIGER protocol to be sustainable over a three-year period. In fact, we identified a trend toward decreased LOS (3.7 days in 2017 to 3.0 days in 2019) as the volume of patients using this pathway increased. These results are like those of Oetgen et al. that used lean process mapping to decrease hospital LOS and narcotic use while optimizing pain control in patients with AIS undergoing fusion. They found these results were sustainable over a 2.5-year period.11 We also found the ERP to be generalizable to institutions with only a single pediatric spine surgeon. In these instances, the efficacy of the ERP may increase as volume increases.
The success of this pathway is most reliant on four core principles of this pathway: 1) systemic understanding of the enhanced recovery protocol from our therapists, nursing staff, patients, and families; 2) a regimented multimodal pain protocol implemented with the help of our anesthesia department; 3) a dedicated NP who is the direct point of contact for all patients undergoing surgery for AIS; and 4) continual biannual education meetings with staff to attempt to further improve the pathway based on new literature. If implemented, there is consistent evidence the ERP will decrease hospital LOS and hospital costs without causing an increase in pain or readmission rate to the hospital.5,7–9
There were multiple limitations with this study that need to be addressed. First, this was a retrospective chart review with unmatched cohorts. This limited our ability to standardize fusion length and a statistically significant longer fusion length was identified in the SP cohort. Additionally, prior to 2015 there was a lower annual volume of patients undergoing PSF at our institution. We therefore used this date as a cutoff since therapists and nurses were not accustomed to working with these patients prior to that time. Finally, we did not record patient satisfaction scores or patient-reported outcomes during this study. However, patient satisfaction has not previously been found to correlate with hospital LOS after implementation of an ERP, so there is no reason to expect a change in patient satisfaction between our two cohorts.12
Conclusion
Our team-based enhanced recovery protocol after posterior spinal fusion in AIS patients resulted in a 26% decrease in hospital LOS without increasing pain scores averaging 3.5 postoperative days. This resulted in a total hospital cost savings of 7.9% with a 7.9% increase to our daily contribution margin and a 10.6% increase in our daily net income. The results of our protocol were sustainable over a three-year period with a trend toward decreasing hospital LOS with an increase in patient volume and further staff education. Our study demonstrates that previous results from ERPs are generalizable to practices with only a single pediatric spine surgeon.
Footnotes
Mark J. Lambrechts, MD, (above), and Melanie E. Boeyer, PhD, are with the University of Missouri - Columbia School of Medicine Department of Orthopaedic Surgery (UMC SOM DOS). Nicole M. Tweedy, DNP-PNP, Sumit K. Gupta, MD, and Daniel G. Hoernschemeyer, MD, are with UMC SOM DOS and the University of Missouri Women’s and Children’s Hospital. Eric T. Kimchi, MD, is with the Harry S. Truman Veterans Hospital. All are in Columbia, Missouri.
Disclosure
DGH: Orthopediatrics: consultant; Zimmer Biomet: research proposal.
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