Thirty-Day Reoperation and Readmission Rates After Correction of Adult Spinal Deformity via Circumferential Minimally Invasive Surgery-Analysis of a 7-Year Experience

An Economic Analysis of Early and Late Complications After Adult Spinal Deformity Correction

STUDY DESIGN/SETTING

Retrospective cohort.

OBJECTIVE

Adult spinal deformity (ASD) corrective surgery is often a highly invasive procedure portending patients to both immediate and long-term complications. Therefore, we sought to compare the economic impact of certain complications before and after 2 years.

METHODS

ASD patients with minimum 3-year data included. Complication groups were defined as follows: any complication, major, medical, mechanical, radiographic, and reoperation. Complications stratified by occurrence before or after 2 years postoperatively. Published methods converted ODI to SF-6D to QALYs. Cost was calculated using CMS.gov definitions. Marginalized means for utility gained and cost-per-QALY were calculated via ANCOVA controlling for significant confounders.

RESULTS

244 patients included. Before 2Y, complication rates: 76% ≥1 complication, 18% major, 26% required reoperation. After 2Y, complication rates: 32% ≥1 complication, 4% major, 2.5% required reoperation. Major complications after 2 years had worse cost-utility (.320 vs .441, P = .1). Patients suffering mechanical complications accrued the highest overall cost ($130,482.22), followed by infection and PJF for complications before 2 years. Patients suffering a mechanical complication after 2 years had lower cost-utility ($109,197.71 vs $130,482.22, P = .041). Patients developing PJF after 2 years accrued a better cost-utility ($77,227.84 vs $96,873.57; P = .038), compared to PJF before 2 years.

CONCLUSION

Mechanical complications had the single greatest impact on cost-utility after adult spinal deformity surgery, but less so after 2 years. Understanding the cost-utility of specific interventions at certain timepoints may mitigate economic burden and prophylactic efforts should strategically be made against early mechanical complications.

Management of severe adult spinal deformity with circumferential minimally invasive surgical strategies without posterior column osteotomies: a 13-year experience

OBJECTIVE

To evaluate the mid- to long-term clinical outcomes of circumferential minimally invasive surgery (CMIS) without posterior column osteotomies for severe adult spine deformity (ASD) correction.

METHODS

All patients with a minimum of 2-year follow-up undergoing staged CMIS correction of ASD from January 2007 to July 2018 were identified. All included patients had fusion of 3 or more interbody levels that spanned the L5-S1 junction. Only patients with severe deformity, Coronal Cobb > 50° or at least one SRS-Schwab ++ sagittal modifier (SVA > 95 mm, or PI-LL > 20, or PT > 30) were included. All complications were noted.

RESULT

136 patients met inclusion criteria; mean age of patients was 63.6 years (21-85, SD 13.7). The mean follow-up was 82.8 months (24-159, SD 36.6). The mean number of levels fused was 7 (3-16, SD 3). A total of 40 (29.4%) major complications were noted at final follow-ups: 2 (1.4%) intra-operative, 12 (8.9%) peri-operative (≤ 6 weeks from index), 26 (19.1%) post-operative (> 6 weeks from index). There was a total of 53 (40.0%) minor complications. Seven (5.1%) patients who developed radiographic proximal junctional kyphosis. Three patients (2.2%) developed proximal junctional failure. There were 8 (5.9%) cases of pseudarthrosis. Five of these occurred in patients undergoing AxiaLIF. All patients experienced improvements in patient-perceived outcomes (VAS, TIS, ODI, and SRS-22) and radiographic parameters at last follow-up when compared to pre-op (p < 0.05).

CONCLUSION

Rates of complications with CMIS correction of severe ASD are lower than published rates of complications seen with open ASD correction. Specifically, the incidence of catastrophic complications is lower. Furthermore, CMIS is associated with significant improvements in clinical and functional outcomes, low rates of pseudarthrosis and proximal junctional kyphosis. Therefore, in the appropriately selected patient, CMIS may be an excellent alternative approach to addressing severe ASD.

Is preoperative S-albumin associated to postoperative complications and readmission in patients with adult spinal deformity: a prospective analysis of 128 patients using the Spine AdVerse Event Severity (SAVES) system

PURPOSE

To assess the association between preoperative S-albumin and postoperative outcome following adult spinal deformity (ASD) surgery.

METHODS

All patients undergoing ASD surgery from February 1, 2017 and January 31, 2018 at a single quaternary referral center were prospectively included. Adverse events (AE) during admission were assessed using the Spine AdVerse Events Severity (SAVES) system. Based on preoperative S-albumin, patients were categorized as "normal" or "abnormal" and compared regarding postoperative outcome, adverse events (AEs), 30- and 90-day readmission, revision surgery, and mortality.

RESULTS

A total of 128 patients aged ≥ 18 years were included, and S-albumin was available in 88%. Of these, 73% (n = 93) were classified as "normal", 16% (n = 20) as "abnormal", and 12% (n = 15) as "missing". The "normal" albumin group had less comorbidity burden [ASA score 2 (2, 3) vs 3 (2, 3), p = 0.011], higher hemoglobin levels (8.4 (± 0.9) mmol/L vs 7.4 (± 1.1) mmol/L, p < 0.001), and higher S-albumin (38.9 (± 2.7) g/L vs 31.9 (± 4.4) g/L, < 0.001). The rate of 90-day readmission was significantly increased in the "abnormal" group (65% vs 36%), corresponding to a relative risk increase of 1.25 (95% CI 1.02-1.52, p = 0.029). Similar increased risks were found in subsequent logistic regression analyses, although results were not significant in multivariable analysis (p = 0.102). Comparing remaining outcome parameters, point estimates revealed increased AEs, 30-day readmission, and revision in the "abnormal" albumin group, although effects did not reach statistical significance.

CONCLUSIONS

In a prospective, consecutive, single-center cohort of 128 patients undergoing ASD surgery, we found a significant association between "abnormal" preoperative S-albumin and increased 90-day readmission. Furthermore, although the findings were not statistically significant, we did find that AEs, 30-day readmission, and revision were numerically more frequent in the "abnormal" group, suggesting an expected tendency that should be further investigated. We conclude that nutritional status prior to ASD surgery could be important to consider and suggest validation in larger prospective cohorts.

LEVEL OF EVIDENCE

Prognostic II.

Preoperative opioids before adult spinal deformity surgery associated with increased reoperations and high rates of chronic postoperative opioid use at 3-year follow-up

PURPOSE

To determine the association of preoperative opioid prescriptions with reoperations and postoperative opioid prescriptions after adult spina deformity (ASD) surgery. With the current opioid crisis, patients undergoing surgery for ASD are at particular risk for opioid-related complications due to significant preoperative disability and surgical morbidity. No previous studies consider preoperative opioids in this population.

METHODS

A retrospective cohort study of patients undergoing posterior spinal fusion (7 or more levels) for ASD was performed. All patients had at least 3 years of postoperative follow-up 3 years postoperatively. Prescriptions for 4 different opioid medications (hydromorphone, oxycodone, hydrocodone, and tramadol) were identified within 3 months preoperatively and up to 3 years postoperatively. Multivariate regression was utilized to determine the association of preoperative use with reoperations and with postoperative opioid use, controlling for both patient and surgery-related confounding factors.

RESULTS

A total of 743 patients were identified and 59.6% (443) had opioid prescriptions within 3 months preoperatively. Postoperative opioid prescriptions were identified in 66.9% of patients at 12 months postoperatively, and in 54.8% at 36 months postoperatively. The 3-year reoperation rate was 11.0% in patients without preoperative prescriptions, 16.0% in patients with preoperative any opioid prescriptions (P = 0.07), and 34.8% in patients with preoperative hydromorphone prescriptions (P < 0.01). In multivariate analysis, preoperative opioid prescriptions were associated with increased reoperations (odds ratio [OR]: 1.62, P = 0.04), and chronic postoperative opioid use (OR: 4.40, P < 0.01). Preoperative hydromorphone prescriptions had the strongest association with both reoperations (OR: 4.96; P < 0.01) and chronic use (OR: 5.19: P = 0.03).

CONCLUSION

In the ASD population, preoperative opioids are associated with both reoperations and chronic opioid use, with hydromorphone having the strongest association. Further investigation of the benefits of preoperative weaning programs is warranted.

Reaching the medicare allowable threshold in adult spinal deformity surgery: multicenter cost analysis comparing actual direct hospital costs versus what the government will pay

STUDY DESIGN

Retrospective multicenter cost analysis.

OBJECTIVE

To (1) determine if index episode of care (iEOC) costs of Adult Spinal Deformity (ASD) surgeries are below the Medicare Allowable (MA) threshold, and (2) identify variables that can predict iEOC cases that are below MA. Previous studies have suggested that actual direct hospital cost of Adult Spinal Deformity (ASD) surgery is higher than Medicare Allowable (MA) rates, which has become the benchmark reimbursement target for hospital accounting systems.

METHODS

From a prospective, multicenter ASD surgical database, patients undergoing long instrumented fusions (> 5 level) with cost data were identified. iEOC cost was calculated utilizing actual direct hospital cost. MA rates were calculated using hospital specific, year-appropriate CMS Inpatient Pricer Payment System. Recursive partitioning identified potentially modifiable variables that can predict iEOC cost < MA.

RESULTS

Administrative direct cost data from 210 patients were obtained from 4 of 11 centers. Ninety-five (45%) patients had iEOC cost < MA. There was significant variation across the four centers in both iEOC cost ($56,788-$78,878, p < 0.0001) and reimbursement ($40,623-$91,351, p < 0.0001) across deformity-specific DRGs (453,454,456,457). Academic centers were more likely to have iEOC costs < MA (67.2% vs 8.9%, p < 0.0001). Recursive partitioning (r² = 0.309) identified rhBMP-2 use of < 24 mg, sagittal plane deformity, a combined anterior/posterior approach, and an SF36-MCS < 39 as predictive for iEOC cost < MA. Performing an anterior/posterior approach reimburses between 14.7% and 121.1% more (2.2-fold) than posterior-only approach. This change in DRG allows iEOC cost to be more likely below the MA threshold.

CONCLUSION

There is significant institutional (private vs academic) variation in ASD reimbursement. BMP use, deformity type, approach, and baseline mental health impact ASD surgery cost being below Medicare reimbursement. ASD surgeries with anterior/posterior approaches are in DRGs that can potentially reimburse 2.2-fold the posterior-only surgery, making it more likely to fall below the MA threshold.

LEVEL OF EVIDENCE

III.

Unplanned Readmissions after Spine Surgery: A Single-Center Prospective Analysis of a 90-Day Model in 2,860 Cases

Study design

Prospective study.

Purpose

During the last decades, an emergence of unplanned readmissions has been shown to be a useful tool to gage the healthcare quality and hospital performance. Previous studies were limited by their retrospective designs based on database information and short-term 30-day follow-up intervals. We analyzed the incidence and causes for unplanned readmissions following spine surgery at a 90-day interval and the difference at 30-, 31–60-, and 61–90-day intervals after discharge. Additionally, we assessed total bed-days lost and the economic impact of readmissions and probable risk factors.

Overview of Literature

Recent reports on readmission rates suggested the contribution of this parameter for the assessment of healthcare quality.

Methods

A prospective analysis of 2,860 admissions was performed over 1 year in a tertiary care orthopedic hospital. All unscheduled readmissions following spine surgery within 90 days of discharge were included, irrespective of type or location of surgery. Polytrauma, primary osseous infections, and planned readmissions were excluded.

Results

Our readmission rate was 3.32% (95/2,860). Leading readmission causes were surgical site infections (SSIs) accounting for 44.21% (n=42; superficial, 23; deep, 11; organ and space, 8), followed by aseptic pain 31.58% (n=30) and medical causes 13.68% (n=13). Though 86.95% of superficial SSIs occurred within 30 days, 21.1% of deep SSIs occurred beyond 30 days. During the 30–90-day interval, 33.68% of readmissions occurred. The financial burden amounted to 41,93,660 Indian Rupees, and the mean bed-days lost was 7.33 per readmission. Hospital stay ≥10 days, health insurance, and comorbid illnesses (diabetes, hypertension, and liver disease) were associated with readmissions (p <0.05).

Conclusions

Our study showed that SSIs and aseptic pain were the leading causes of readmissions at 90 days after spine surgery. Limiting the analysis to 30-day readmissions as in previous studies would lead to failure in the identification of more severe complications like deep SSIs. Continued vigilance, particularly for patients with predisposing factors, could help alleviate the financial burden.

The Prevalence of the Use of MIS Techniques in the Treatment of Adult Spinal Deformity (ASD) Amongst Members of the Scoliosis Research Society (SRS) in 2016

STUDY DESIGN

Electronic survey administered to Scoliosis Research Society members.

OBJECTIVE

To determine the prevalence of minimally invasive surgery (MIS) techniques for the treatment of adult spinal deformity.

SUMMARY OF BACKGROUND DATA

There is a paucity of data available on the practice pattern, prevalence of minimally invasive spine surgery, and the preferred minimally invasive techniques in the treatment of adult spine deformity.

METHODS

An electronic nine-question survey regarding individual usage pattern of minimally invasive spine surgery techniques was administered in 2016 to the members of the Scoliosis Research Society. Determinants included complexity in condition of patient population, prevalence of use of minimally invasive techniques in the surgeon's practice, prevalence of use of a particular MIS technique, strategy elected during surgery, adoption of staging of procedures and timing between staging of procedures.

RESULTS

A total of 357 surgeons responded (61.3% response rate), and 154 (43.1%) of the respondents said that they use MIS as a part of their surgical treatment of adult spinal deformity. However, of these 154 respondents, 67 (43.5%) said that their MIS usage in deformity practice was between 1% and 20%. Only 11 (7.2%) said that they used MIS 81% to 100% of the time. The top MIS approaches that surgeons chose were MIS lateral lumbar interbody fusion 109 (70.59%) and MIS percutaneous screws 91 (58.8%).

CONCLUSIONS

The low rate of adoption of these techniques among the SRS members may be due to the false perception that there is not enough data to support that MIS techniques are better. This and the fact that a practitioner needs to be facile at different MIS techniques may be the true impediment to the adoption of MIS techniques in the treatment of ASD.

LEVEL OF EVIDENCE

Level IV.

The comprehensive anatomical spinal osteotomy and anterior column realignment classification

OBJECTIVESpinal osteotomies and anterior column realignment (ACR) are procedures that allow preservation or restoration of spine lordosis. Variations of these techniques enable different degrees of segmental, regional, and global sagittal realignment. The authors propose a comprehensive anatomical classification system for ACR and its variants based on the level of technical complexity and invasiveness. This serves as a common language and platform to standardize clinical and radiographic outcomes for the utilization of ACR.METHODSThe proposed classification is based on 6 anatomical grades of ACR, including anterior longitudinal ligament (ALL) release, with varying degrees of posterior column release or osteotomies. Additionally, a surgical approach (anterior, lateral, or posterior) was added. Reliability of the classification was evaluated by an analysis of 16 clinical cases, rated twice by 14 different spine surgeons, and calculation of Fleiss kappa coefficients.RESULTSThe 6 grades of ACR are as follows: grade A, ALL release with hyperlordotic cage, intact posterior elements; grade 1 (ACR + Schwab grade 1), additional resection of the inferior facet and joint capsule; grade 2 (ACR + Schwab grade 2), additional resection of both superior and inferior facets, interspinous ligament, ligamentum flavum, lamina, and spinous process; grade 3 (ACR + Schwab grade 3), additional adjacent-level 3-column osteotomy including pedicle subtraction osteotomy; grade 4 (ACR + Schwab grade 4), 2-level distal 3-column osteotomy including pedicle subtraction osteotomy and disc space resection; and grade 5 (ACR + Schwab grade 5), complete or partial removal of a vertebral body and both adjacent discs with or without posterior element resection. Intraobserver and interobserver reliability were 97% and 98%, respectively, across the 14-reviewer cohort.CONCLUSIONSThe proposed anatomical realignment classification provides a consistent description of the various posterior and anterior column release/osteotomies. This reliability study confirmed that the classification is consistent and reproducible across a diverse group of spine surgeons.

Minimally Invasive Spinal Surgery for Adult Spinal Deformity

The purpose of this review is to present the current techniques and outcomes of adult spine deformity (ASD) surgery using the minimally invasive spine surgery (MISS) approach. We performed a systemic search of PubMed for literature published through January 2018 with the following terms: "minimally invasive spine surgery," "adult spinal deformity," and "degenerative scoliosis." Of the 138 items that were found through this search, 57 English-language articles were selected for full-text review. According to the severity of the deformity and the symptoms, various types of MISS have been utilized, such as MISS decompression, circumferential MISS, and hybrid surgery. With proper indications, the MISS approach achieved satisfactory clinical and radiological outcomes for ASD, with reduced complication rates. Future studies should aim to define clear indications for the application of various surgical options.