Cost and Hospital Resource Utilization of Staphylococcus aureus Infection Post Elective Posterior Instrumented Spinal Fusion Surgeries in U.S. Hospitals: A Retrospective Cohort Study

State-of-the-Art Review: Diagnosis and Management of Spinal Implant Infections

Spinal implant infections are a serious complications of instrumented spinal fusion surgeries, carrying high morbidity and complex management challenges. Early postoperative infections may manifest with wound-healing issues, back pain, and fevers. Magnetic resonance imaging (MRI) is the preferred imaging modality, but can be limited by metal artifacts. For cases with stable implants, surgical debridement with implant retention combined with at least 12 weeks of antibiotics is currently considered appropriate treatment. Staphylococcal infections are ideally treated with biofilm-active antibiotics. Suppressive antibiotic therapy can be considered when surgical debridement has been delayed or is incomplete, and for those who are poor surgical candidates for another surgery. Chronic infections may present insidiously with implant failure or pseudarthrosis; implant removal or revision is generally pursued. As current guidance is heavily based on the periprosthetic joint infection literature and low-level studies on spinal implant infections, further research on optimizing diagnostic and treatment approaches is needed.

Implications of surgical infection on surgical and hospital outcomes after spine surgery: A NSQIP study of 410,930 patients

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Surgical infections are unfortunately a fairly common occurrence in spine surgery, with rates reported as high as 16 %. However, there is a relative paucity of studies that look to understand how surgical infections may impact outcome variables. The aim of this study was to assess the impact of surgical infection on other perioperative complications, extended hospital length of stay (LOS), discharge disposition, and unplanned readmission following spine surgery.

METHODS

A retrospective cohort study was performed using the 2016-2022 ACS NSQIP database. Adults receiving spine surgery for trauma, degenerative disease, and tumors were identified using CPT and ICD-9/10 codes. Patients were divided into two cohorts: surgical infection (superficial surgical site infection, deep surgical site infection, organ space surgical site infection, or wound dehiscence) and no surgical infection (those who did not experience any infection). Patient demographics, comorbidities, intraoperative variables, postoperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analysis was utilized to identify predictors of AEs, extended hospital length of stay, non-routine discharge, and unplanned readmission.

RESULTS

In our cohort of 410,930 patients, 7854 (2.2 %) were found to have experienced a surgical infection. Regarding preoperative variables, a greater proportion of the surgical infection cohort was a female (p < 0.001) and had a higher mean BMI (p < 0.001), greater frailty and ASA scores (p < 0.001), and higher rates of all presenting comorbidities included in the study. Rates of AEs (p < 0.001), unplanned readmission (p < 0.001), reoperation (p < 0.001), non-home discharge (p < 0.001), and 30-day mortality were all greater in the surgical infection group when compared to the group without surgical infection. On multivariate analysis, surgical infection was found to be an independent predictor of experiencing postoperative complications [aOR: 6.15, 95 % CI: (5.72, 6.60), p < 0.001], prolonged LOS [2.71, 95 % CI: (2.54, 2.89), p < 0.001], non-routine discharge [aOR: 1.74, 95 % CI: (1.61, 1.88), p < 0.001], and unplanned readmission [aOR: 22.57, 95 % CI: (21.06, 24.19), p < 0.001].

CONCLUSIONS

Our study found that surgical infection increases the risk of complications, extended LOS, non-routine discharge, and unplanned readmission. Such findings warrant further studies that aim to validate these results and identify risk factors for surgical infections.

Preoperative Opioid Use Increases Postoperative Opioid Demand, but Not Length of Stay After Spine Trauma Surgery

BACKGROUND

Preoperative opioid use has been well-studied in elective spinal surgery and correlated with numerous postoperative complications including increases in immediate postoperative opioid demand (POD), continued opioid use postoperatively, prolonged length of stay (LOS), readmissions, and disability. There is a paucity of data available on the use of preoperative opioids in surgery for spine trauma, possibly because there are minimal options for opioid reduction prior to emergent spinal surgery. Nevertheless, patients with traumatic spinal injuries are at a high risk for adverse postoperative outcomes. This study investigated the effects of preoperative opioid use on POD and LOS in spine trauma patients.

METHODS

130 patients were grouped into two groups for primary comparison: Group 1 (preoperative opioid use, N = 16) and Group 2 (no opioid use, N = 114). Two subgroups of Group 2 were used for secondary analysis against Group 1: Group 3 (no substance abuse, N = 95) and Group 4 (other substance abuse, N = 19). Multivariable analysis was used to determine if there were significant differences in POD and LOS.

RESULTS

Primary analysis demonstrated that preoperative opioid users required an estimated 97.5 mg/day more opioid medications compared to non-opioid users (P < 0.001). Neither primary nor secondary analysis showed a difference in LOS in any of the comparisons.

CONCLUSIONS

Preoperative opioid users had increased POD compared to non-opioid users and patients abusing other substances, but there was no difference in LOS. We theorize the lack of difference in LOS may be due to the enhanced perioperative recovery protocol used, which has been demonstrated to reduce LOS.

The Impact of Corticosteroid Injection Timing on Infection Rates Following Spine Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN/SETTING

Systematic review/meta-analysis.

OBJECTIVES

The objective of this review was to assess how the risk of infection following lumbar spine surgery varies as a function of the timing of preoperative corticosteroid spinal injections (CSIs).

METHODS

A systematic review and meta-analysis was performed in accordance with the PRISMA guidelines. PubMed and EMBASE databases were searched and data was pooled for meta-analysis.

RESULTS

Six studies were identified for inclusion. Two (33.3%) demonstrated a significant relationship between the timing of preoperative CSIs and the risk of postoperative infection, while 4 (66.7%) demonstrated no impact. A total of 2.5% (110/4,448) of patients who underwent CSI <1 month before surgery experienced a postoperative infection, as compared to 1.2% (1,466/120, 943) of controls, which was statistically significant (RR = 1.986 95% CI 1.202-3.282 P = 0.007). A total of 1.6% (25/1,600) of patients who underwent CSI 0-3 months before surgery experienced a postoperative infection, as compared to 1.6% (201/12, 845) of controls (RR = 0.887 95% CI 0.586-1.341, P = 0.569). A total of 1.1% (199/17 870) of patients who underwent CSI 3-6 months before surgery experienced a postoperative infection, as compared to 1.3% (1,382/102, 572) of controls (RR = 1.053 95% CI 0.704-1.575, P = 0.802). Differences in infection risk for 0-3 months and 3-6 months were not statistically significant.

CONCLUSIONS

CSIs <1 month prior to lumbar spine surgery are a significant risk factor for infection, while CSIs beyond that point showed no such association. Surgeons should consider avoiding CSIs <1 month of the use of CSIs of the spine.

A 24-month retrospective update: follow-up hospitalization charges and readmissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2)

Background

The objectives of this study were to build upon previously-reported 12-month findings by retrospectively comparing 24-month follow-up hospitalization charges and potentially-relevant readmissions in US lumbar fusion surgeries that employed either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a nationwide healthcare system database.

Methods

A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2 in the original study, of whom 3,792 patients (23.4%) were identified in the current study with all-cause readmissions during the 24-month follow-up period. Confounding baseline patient, procedure, and hospital characteristics found in the original study were used to adjust multivariate regression models comparing differences in 24-month follow-up hospitalization charges (in 2020 US dollars) and lengths of stay (LOS; in days) between the groups. Differences in potentially-relevant follow-up readmissions were also compared, and all analyses were repeated in the subset of patients who only received treatment at a single level of the spine.

Results

The adjusted cumulative mean 24-month follow-up hospitalization charges in the full cohort were significantly lower in the V-CBA group ($99,087) versus the rhBMP-2 group ($124,389; P < 0.0001), and this pattern remained in the single-level cohort (V-CBA = $104,906 vs rhBMP-2 = $125,311; P = 0.0006). There were no differences between groups in adjusted cumulative mean LOS in either cohort. Differences in the rates of follow-up readmissions aligned with baseline comorbidities originally reported for the initial procedure. Subsequent lumbar fusion rates were significantly lower for V-CBA patients in the full cohort (10.12% vs 12.00%; P = 0.0002) and similar between groups in the single-level cohort, in spite of V-CBA patients having significantly higher rates of baseline comorbidities that could negatively impact clinical outcomes, including bony fusion.

Conclusions

The results of this study suggest that use of V-CBA for lumbar fusion surgeries performed in the US is associated with substantially lower 24-month follow-up hospitalization charges versus rhBMP-2, with both exhibiting similar rates of subsequent lumbar fusion procedures and potentially-relevant readmissions.

Incontinence and Incontinence-Associated Dermatitis in Acute Care: A Retrospective Analysis of Total Cost of Care and Patient Outcomes From the Premier Healthcare Database

PURPOSE

To evaluate the prevalence of incontinence and treatment of incontinence-associated dermatitis (IAD) and associations with outcomes including total cost of care, length of stay (LOS), 30-day readmission, sacral area pressure injuries present on admission and hospital acquired pressure injuries, and progression of all sacral area pressure injuries to a higher stage.

DESIGN

Retrospective analysis.

SUBJECTS AND SETTINGS

Data were retrieved from the Premier Healthcare Database and comprised more than 15 million unique adult patient admissions from 937 hospitals. Patients were 18 years or older and admitted to a participating hospital between January 1, 2016, and December 31, 2019.

METHODS

Given the absence of an IAD International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) code, we categorized patients treated for IAD by selecting patients with a documented incontinence ICD-10-CM code and a documented charge for dermatology products used to treat IAD. The t test and χ2 tests determined whether incontinence and treatment for IAD were associated with outcomes.

RESULTS

Incontinence prevalence was 1.5% for the entire sample; prevalence rate for IAD among incontinent patients was 0.7%. As compared to continent patients, incontinent patients had longer LOS (6.4 days versus 4.4 days), were 1.4 times more likely to be readmitted, 4.7 times more likely to have a sacral pressure injury upon admission pressure injury, 5.1 times more likely to have a sacral hospital-acquired pressure injury, and 5.8 times more likely to have a sacral pressure injury progress to a severe stage. As compared to incontinent patients without IAD treatment, those with IAD treatment had longer LOS (9.7 days versus 6.4 days), were 1.3 times more likely to be readmitted, and were 2.0 times more likely to have a sacral hospital-acquired pressure injury. Total index hospital costs were 1.2 times higher for incontinent patients and 1.3 times higher for patients with IAD treatment.

CONCLUSIONS

Incontinence and IAD prevalence are substantially lower than past research due to underreporting of incontinence. The lack of an ICD-10-CM code for IAD further exacerbates the underreporting of IAD. Despite low prevalence numbers, our results show higher health care costs and worse outcomes for incontinent patients and patients with IAD treatment.

Evaluation of the costing methodology of published studies estimating costs of surgical site infections: A systematic review

OBJECTIVES

Surgical site infections (SSIs) are associated with increased length of hospitalization and costs. Epidemiologists and infection control practitioners, who are in charge of implementing infection control measures, have to assess the quality and relevance of the published SSI cost estimates before using them to support their decisions. In this review, we aimed to determine the distribution and trend of analytical methodologies used to estimate cost of SSIs, to evaluate the quality of costing methods and the transparency of cost estimates, and to assess whether researchers were more inclined to use transferable studies.

METHODS

We searched MEDLINE to identify published studies that estimated costs of SSIs from 2007 to March 2021, determined the analytical methodologies, and evaluated transferability of studies based on 2 evaluation axes. We compared the number of citations by transferability axes.

RESULTS

We included 70 studies in our review. Matching and regression analysis represented 83% of analytical methodologies used without change over time. Most studies adopted a hospital perspective, included inpatient costs, and excluded postdischarge costs (borne by patients, caregivers, and community health services). Few studies had high transferability. Studies with high transferability levels were more likely to be cited.

CONCLUSIONS

Most of the studies used methodologies that control for confounding factors to minimize bias. After the article by Fukuda et al, there was no significant improvement in the transferability of published studies; however, transferable studies became more likely to be cited, indicating increased awareness about fundamentals in costing methodologies.

Spine Instrumented Surgery on a Budget-Tools for Lowering Cost Without Changing Outcome

STUDY DESIGN

Review article.

OBJECTIVES

There have been substantial increases in the utilization of complex spinal surgery in the last 20 years. Spinal instrumented surgery is associated with high costs as well as significant variation in approach and care. The objective of this manuscript is to identify and review drivers of instrumented spine surgery cost and explain how surgeons can reduce costs without compromising outcome.

METHODS

A literature search was conducted using PubMed. The literature review returned 217 citations. 27 publications were found to meet the inclusion criteria. The relevant literature on drivers of spine instrumented surgery cost is reviewed.

RESULTS

The drivers of cost in instrumented spine surgery are varied and include implant costs, complications, readmissions, facility-based costs, surgeon-driven preferences, and patient comorbidities. Each major cost driver represents an opportunity for potential reductions in cost. With high resource utilization and often uncertain outcomes, spinal surgery has been heavily scrutinized by payers and hospital systems, with efforts to reduce costs and standardize surgical approach and care pathways.

CONCLUSIONS

Education about cost and commitment to standardization would be useful strategies to reduce cost without compromising patient-reported outcomes after instrumented spinal fusion.

A large database study of hospitalization charges and follow-up re-admissions in US lumbar fusion surgeries using a cellular bone allograft (CBA) versus recombinant human bone morphogenetic protein-2 (rhBMP-2)

Background

The objective of this study was to retrospectively compare initial procedure and 12-month follow-up hospitalization charges and resource utilization (lengths of stay; LOS) for lumbar fusion surgeries using either recombinant human bone morphogenetic protein-2 (rhBMP-2) or a cellular bone allograft comprised of viable lineage-committed bone cells (V-CBA) via a large US healthcare system database. Potentially relevant re-admissions during the follow-up period were also assessed.

Methods

A total of 16,172 patients underwent lumbar fusion surgery using V-CBA or rhBMP-2, of whom 3503 (21.66%) patients had follow-up re-admission data. Initial patient, procedure, and hospital characteristics were assessed to determine confounding factors. Multivariate regression modeling compared differences in hospitalization charges (in 2018 US dollars) and LOS (in days) between the groups, as well as incidences of potentially relevant re-admissions during the 12-month follow-up period.

Results

The adjusted mean initial procedure and 12-month follow-up hospital charges were significantly lower in the V-CBA group versus the rhBMP-2 group ($109,061 and $108,315 versus $160,191 and $130,406, respectively; P < 0.0001 for both comparisons). This disparity remained in an ad hoc comparison of charges for initial single-level treatments only (V-CBA = $103,064, rhBMP-2 = $149,620; P < 0.0001). The adjusted mean initial LOS were significantly lower in the V-CBA group (3.77 days) versus the rhBMP-2 group (3.88 days; P < 0.0001), but significantly higher for the cumulative follow-up hospitalizations in the 12-month follow-up period (7.87 versus 7.46 days, respectively; P < 0.0001). Differences in rates of follow-up re-admissions aligned with comorbidities at the initial procedure. Subsequent lumbar fusion rates were comparable, but significantly lower for V-CBA patients who had undergone single-level treatments only, in spite of V-CBA patients having significantly higher rates of initial comorbidities that could negatively impact clinical outcomes.

Conclusions

The results of this study indicate that use of V-CBA for lumbar fusion surgeries performed in the US may result in substantially lower overall hospitalization charges versus rhBMP-2, with both exhibiting similar rates of 12-month re-admissions and subsequent lumbar fusion procedures.

Utility of the Hospital Frailty Risk Score for Predicting Adverse Outcomes in Degenerative Spine Surgery Cohorts

BACKGROUND

As spine surgery becomes increasingly common in the elderly, frailty has been used to risk stratify these patients. The Hospital Frailty Risk Score (HFRS) is a novel method of assessing frailty using International Classification of Diseases, Tenth Revision (ICD-10) codes. However, HFRS utility has not been evaluated in spinal surgery.

OBJECTIVE

To assess the accuracy of HFRS in predicting adverse outcomes of surgical spine patients.

METHODS

Patients undergoing elective spine surgery at a single institution from 2008 to 2016 were reviewed, and those undergoing surgery for tumors, traumas, and infections were excluded. The HFRS was calculated for each patient, and rates of adverse events were calculated for low, medium, and high frailty cohorts. Predictive ability of the HFRS in a model containing other relevant variables for various outcomes was also calculated.

RESULTS

Intensive care unit (ICU) stays were more prevalent in high HFRS patients (66%) than medium (31%) or low (7%) HFRS patients. Similar results were found for nonhome discharges and 30-d readmission rates. Logistic regressions showed HFRS improved the accuracy of predicting ICU stays (area under the curve [AUC] = 0.87), nonhome discharges (AUC = 0.84), and total complications (AUC = 0.84). HFRS was less effective at improving predictions of 30-d readmission rates (AUC = 0.65) and emergency department visits (AUC = 0.60).

CONCLUSION

HFRS is a better predictor of length of stay (LOS), ICU stays, and nonhome discharges than readmission and may improve on modified frailty index in predicting LOS. Since ICU stays and nonhome discharges are the main drivers of cost variability in spine surgery, HFRS may be a valuable tool for cost prediction in this specialty.

[The effectiveness of local application of vancomycin powder in the prevention of surgical site infections in spine surgery: a meta-analysis]

OBJECTIVE

To perform a meta-analysis of studies examining the effectiveness of the local application of vancomycin powder for the prophylaxis of surgical site infections (SSIs) in spine surgery.

MATERIAL AND METHODS

Retrospective cohort studies and prospective randomized clinical trials were searched for in the Pubmed, EMBASE, Cochrane Library and eLibrary databases published from 2008 to December 2018. For the resulting variables, the odds ratio and 95% confidence interval were calculated using random and fixed effects models. Estimation of the degree of heterogeneity is estimated using the coefficient I². Statistically significant differences were considered differences p<0.05.

RESULTS

The meta-analysis included 28 clinical studies that included the results of the local application of vancomycin powder in 17,469 patients after performing various spinal surgical interventions. Two publications had a prospective, randomized, controlled study design. Topical application of vancomycin powder reduces the incidence of SSIs after spine surgery (p<0.0001). The use of vancomycin powder reduces the incidence of SSIs in patients operated on with stabilizing implants (p=0.004). On the other hand, the topical application of vancomycin powder did not affect the prevalence of SSIs in respondents who were operated on without the use of stabilizing implants (p=0.12) or due to deformities of the spine (p=0.06).

CONCLUSION

Topical application of vancomycin powder is highly effective in preventing the development of SSIs in patients after spinal surgical interventions.

Readmission in elective spine surgery: Will short stays be beneficial to patients

There has been limited discussion as to whether spine surgery patients are benefiting from shorter in-patient hospital stays or if they are incurring higher rates of readmission and complications secondary to shortened length of stays. Included in this study were 237,446 spine patients >18yrs and excluding infection. Patients with Clavien Grade 5 complications in 2015 had the lowest mean time to readmission after initial surgery in all years at 12.44 ± 9.03 days. Pearson bivariate correlations between LOS ≤ 1 day and decreasing days to readmission was the strongest in 2016.). Logistic regression analysis found that LOS ≤ 1 day showed an overall increase in the odds of hospital readmission from 2012 to 2016 (2.29 [2.00-2.63], 2.33 [2.08-2.61], 2.35 [2.11-2.61], 2.27 [2.06-2.49], 2.33 [2.14-2.54], all p < 0.001).

Prediction tool for high risk of surgical site infection in spinal surgery

OBJECTIVE

The incidence of surgical site infection (SSI) is higher in spinal surgeries than in general orthopedic operations. In this study, we aimed to develop a scoring system with reduced health care costs for detecting spinal surgery patients at high risk for SSI.

DESIGN

Retrospective cohort study.

PATIENTS

In total, 824 patients who underwent spinal surgery at 2 university hospitals from September 2005 to May 2011.

METHODS

We reviewed the medical records of 824 patients, and we examined 19 risk factors to identify high-risk patients. After narrowing down the variables by univariate analysis, multiple logistic analysis was performed for factors with P values <.2, using SSI as a dependent variable. Only factors that showed P values <.05 were included in the final models, and each factor was scored based on the β coefficient values obtained. The clinical prediction rules were thereby prepared.

RESULTS

"Emergency operation," "blood loss >400 mL," "presence of diabetes," "presence of skin disease," and "total serum albumin value <3.2 g/dL" were detected by multivariable modeling and were incorporated into the risk scores. Applying these 5 independent predictive factors, we were able to predict the infection incidence after spinal surgery.

CONCLUSIONS

Our present study could aid physicians in making decisions regarding prevention strategies in patients undergoing spinal surgery. Stratification of risks employing this scoring system will facilitate the identification of patients most likely to benefit from complex, time-consuming and expensive infection prevention strategies, thereby possibly reducing healthcare costs.

Impact of medical student involvement on outcomes following spine surgery: A single center analysis of 6485 patients

Medical student (MS) observation and assistance in the operating room (OR) is a critical component of medical education. Though participation in the operating room has many benefits to the medical student, the potential cost of these experiences to the patients must be taken into account. Other studies have shown differences in outcomes with resident involvement, but the effect of medical students in the OR has been poorly understood. The objective of this study was to understand how medical students and residents impacted surgical outcomes in posterior spinal fusions, anterior cervical discectomy and fusions (ACDFs), and lumbar discectomies. We conducted a retrospective study of patients undergoing posterior spinal fusions, ACDFs, and lumbar discectomies over 15 years. There were 6485 patients met the inclusion criteria of either undergoing a posterior fusion, ACDF or lumbar discectomy (1250 posterior fusion, 1381 ACDF, 3854 lumbar discectomies). Overall, little difference was observed when a medical student was present for surgical outcomes including length of stay, infection, and readmission. For ACDFs, having a medical student present had a significantly longer procedure durations (OR = 1.612, p = 0.001) than cases without. Besides slightly longer operative time (in posterior fusions), there were no major differences in outcomes when a medical student was present in the OR.