Surgical outcomes of long spinal fusions for scoliosis in adult patients with rheumatoid arthritis

Rheumatoid Arthritis in Spine Surgery: A Systematic Review and Meta-Analysis

STUDY DESIGN

Systematic Review and Meta-analysis.

OBJECTIVE

The purpose of this study is to synthesize recommendations for perioperative medical management of RA patients and quantify outcomes after spine surgery when compared to patients without RA.

METHODS

A search of available literature on patients with RA and spine surgery was performed. Studies were included if they provided a direct comparison of outcomes between patients undergoing spine surgery with or without RA diagnosis. Meta-analysis was performed on operative time, estimated blood loss, hospital length of stay, overall complications, implant-related complications, reoperation, infection, pseudarthrosis, and adjacent segment disease.

RESULTS

Included in the analysis were 9 studies with 703 patients with RA undergoing spine surgery and 2569 patients without RA. In RA patients compared to non-RA patients undergoing spine surgery, the relative risk of infection was 2.29 times higher (P = .036), overall complications 1.61 times higher (P < .0001), implant-related complications 3.93 times higher (P = .009), and risk of reoperation 2.45 times higher (P < .0001). Hospital length of stay was 4.6 days longer in RA patients (P < .0001).

CONCLUSIONS

Treatment of spinal pathology in patients with RA carries an increased risk of infection and implant-related complications. Spine-specific guidelines for perioperative management of antirheumatic medication deserve further exploration. All RA patients should be perioperatively co-managed by a rheumatologist. This review helps identify risk profiles in RA specific to spine surgery and may guide future studies seeking to medically optimize RA patients perioperatively.

Postoperative outcomes after degenerative lumbar spine surgery in rheumatoid arthritis patients -a propensity score-matched analysis

Background

Although treatment options for rheumatoid arthritis (RA) have evolved significantly since the introduction of biologic agents, degenerative lumbar disease in RA patients remains a major challenge. Well-controlled comparisons between RA patients and their non-RA counterparts have not yet been reported. The objective of the present study was to compare postoperative outcomes of lumbar spine surgery between RA and non-RA patients by a retrospective propensity score-matched analysis.

Methods

Patients who underwent primary posterior spine surgery for degenerative lumbar disease in our prospective multicenter study group between 2017 and 2020 were enrolled. Demographic data including age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) physical status classification, diabetes mellitus, smoking, steroid usage, number of spinal levels involved, and preoperative patient-reported outcome (PRO) scores (numerical rating scale [NRS] for back pain and leg pain, Short Form-12 physical component summary [PCS], EuroQOL 5-dimension [EQ-5D], and Oswestry Disability Index [ODI]) were used to calculate a propensity score for RA diagnosis. One-to-one matching was performed and 1-year postoperative outcomes were compared between groups.

Results

Among the 4567 patients included, 90 had RA (2.0%). RA patients in our cohort were more likely to be female, with lower BMI, higher ASA grade and lower current smoking rate than non-RA patients. Preoperative NRS scores for leg pain, PCS, EQ-5D, and ODI were worse in RA patients. Propensity score matching generated 61 pairs of RA and non-RA patients who underwent posterior lumbar surgery. After background adjustment, RA patients reported worse postoperative PCS (28.4 vs. 37.2, p = 0.008) and EQ-5D (0.640 vs. 0.738, p = 0.03), although these differences were not significant between RA and non-RA patients not on steroids.

Conclusions

RA patients showed worse postoperative quality of life outcomes after posterior surgery for degenerative lumbar disease, while steroid-independent RA cases showed equivalent outcomes to non-RA patients.

Impact of Obesity on Complications and Surgical Outcomes of Adult Degenerative Scoliosis with Long- Segment Spinal Fusion

INTRODUCTION

The relationship between obesity and outcome of spine surgery has been controversial. The impact of obesity on surgical outcomes of patients undergoing long- segment (6 vertebrae or more) spinal fusion have not been studied. This study was designed to define the influence of obesity on the outcomes of patients undergoing long-segment spinal fusion.

METHODS AND MATERIALS

A retrospective study of patients undergoing long-segment (6 vertebrae or more) spinal fusion was realized. Patients were divided into non-obese group and obese group. Variables such as blood loss, operative time, length of stay, complications, reoperation rates, and clinical outcome were compared between the two groups.

RESULTS

Thirty-four non-obese patients (BMI: 26.43 ± 0.87) and 27 obese ones (BMI: 35.35 ± 1.81) were recruited. Number of fused levels in non-obese group was not significantly different from obese group (9.06±0.57 vertebrae vs 8.85±0.68 vertebrae, p=0.65). There was no significant difference between non-obese group and obese group in the blood loss during surgery (p= 0.12), the operating time (p=0.46) and the length of hospitalization (p=0.64). Similarly, no significant difference was found in surgical complications (p= 0.76) and medical complications (p=0.82) between the two groups. The rate of ambulatory improvement is similar between non-obese group and obese group (p=0.64).

CONCLUSION

Our study showed that there was no relationship between obesity and adverse surgical outcomes in ADS surgery with long-segment (6 vertebrae or more) spinal fusion.

Incidence of and risk factors for spondylolisthesis, scoliosis, and vertebral fracture in rheumatoid arthritis

INTRODUCTION

Although lumbar lesions such as spondylolisthesis, scoliosis, and vertebral fracture are not specific to rheumatoid arthritis (RA), the prevalence is high in RA patients. However, no longitudinal study has evaluated lumbar lesions in RA. This study aimed to investigate the incidence of and risk factors for lumbar lesions in RA by a prospective longitudinal cohort study.

MATERIALS AND METHODS

The study cohort comprised 110 patients with RA from the 'analysis of factors for RA spinal disorders (AFFORD)' study who completed the secondary survey at a single orthopaedic outpatient RA clinic. Radiological examination included standing radiographs and magnetic resonance imaging (MRI) of the lumbar spine. New development of spondylolisthesis, scoliosis, and vertebral fracture were assessed between baseline and secondary survey.

RESULTS

The incidences of spondylolisthesis, scoliosis, and vertebral fracture were 42%, 16%, and 12%, respectively, during a mean follow-up of 7 years. The independent risk factor for de novo scoliosis was poor control of RA (adjusted odds ratio [aOR] 4.81, p = 0.011), while the independent risk factors for new vertebral fracture was use of glucocorticoid at secondary survey (aOR 14.87, p = 0.012). Patients with de novo scoliosis exhibited more severe low back pain and lower quality of life than those without.

CONCLUSION

The incidence of scoliosis was related in patients with poor control of RA, while new vertebral fracture was more common in patients with use of glucocorticoid. Control of disease activity might be important in preventing radiological lumbar disorders in RA.

Radiological and clinical comparisons of the patients with rheumatoid arthritis operated with rigid and dynamic instrumentation systems due to lumbar degenerative spinal diseases

BACKGROUND

It is extremely difficult to treat spine disorders with stabilization in patients with rheumatoid arthritis. Because revision rates are significantly higher in rigid stabilization. To date, there is no data about patients with rheumatoid arthritis treated with dynamic stabilization. Our aim was to compare the radiological and clinical results of patients with rheumatoid arthritis who underwent lumbar rigid stabilization or dynamic stabilization with Polyetheretherketone rod (PEEK).

METHODS

Patients with degenerative lumbar spine disease with rheumatoid arthritis who underwent dynamic stabilization between 2013 and 2015 and rigid stabilization between 2010 and 2012 were evaluated radiologically for adjacent segment disease, proximal junctional kyphosis, system problem (nonunion, screw loosening, instrumentation failure, pull out). It was also compared according to both the revision rates and the Visual Analog Scale and Oswestry Disability Index scores at the 12th month and 24th month.

RESULTS

The difference of decrease in Visual Analog Scale and Oswestry Disability Index scores from preoperative to 12th month between patients who underwent dynamic stabilization and rigid stabilization was statistically insignificant. However, there was a significant difference of increase in Visual Analog Scale and Oswestry Disability Index scores between the 12th month and 24th month of patients who underwent rigid stabilization, compared with patients with dynamic stabilization. In patients with dynamic stabilization, the problems of instrumentation were seen less frequently. Revision rates were high in patients with rigid stabilization when compared the patients with dynamic stabilization.

CONCLUSION

Radiological and clinical outcomes in patients with rheumatoid arthritis operated with dynamic stabilization are more significant when compared to rigid stabilization. These patients have lower pain and disability scores in their follow up periods. Revision rates are lower in patients with dynamic stabilization.

Surgical Site Infection, Readmission, and Reoperation After Posterior Long Segment Fusion

STUDY DESIGN

Retrospective case series.

OBJECTIVE

We sought to identify risk factors associated with surgical site infection (SSI) after posterior long segment spinal fusion (PLSF).

SUMMARY OF BACKGROUND DATA

Patients who undergo PLSF may be at elevated risk of SSI. Identifying factors associated with SSI in these operations can help risk stratify patients and tailor management.

METHODS

We analyzed PLSFs-seven or more levels-at our institution from 2000 to 2015. Data on patients' clinical characteristics, procedural factors, and antimicrobial management were collected. Multivariable analysis identified factors independently associated with outcomes of interest.

RESULTS

In 628 cases, SSI was associated with steroid use (P = 0.024, odds ratio [OR] = 2.54) and using cefazolin (P < 0.001, OR = 4.37) or bacitracin (P = 0.010, OR 3.49) irrigation, as opposed to gentamicin or other irrigation. Gram-positive infections were more likely with staged procedures (P = 0.021, OR 4.91) and bacitracin irrigation (P < 0.001, OR = 17.98), and less likely with vancomycin powder (P = 0.050, OR 0.20). Gram-negative infections were more likely with a history of peripheral arterial disease (P = 0.034, OR = 3.21) or cefazolin irrigation (P < 0.001, OR 25.47). Readmission was more likely after staged procedures (P = 0.003, OR = 3.31), cervical spine surgery (P = 0.023, OR = 2.28), or cefazolin irrigation (P = 0.039, OR = 1.85). Reoperation was more common with more comorbidities (P = 0.022, OR 1.09), staged procedures (P < 0.001, OR = 4.72), cervical surgeries (P = 0.013, OR = 2.36), more participants in the surgery (P = 0.011, OR = 1.06), using cefazolin (P < 0.001, OR = 3.12) or bacitracin (P = 0.009, OR = 3.15) irrigation, and higher erythrocyte sedimentation rate at readmission (P = 0.009, OR = 1.04). Washouts were more likely among patients with more comorbidities (P = 0.013, OR = 1.16), or who used steroids (P = 0.022, OR = 2.92), and less likely after cervical surgery (P = 0.028, OR = 0.24). Instrumentation removal was more common with bacitracin irrigation (p = 0.013, OR = 31.76).

CONCLUSION

Patient factors, whether a procedure is staged, and choice of antibiotic irrigation affect the risk of SSI and ensuing management required.Level of Evidence: 4.

Role of oxidative metabolism in osseointegration during spinal fusion

Spinal fusion is a commonly performed orthopedic surgery. Autologous bone graft obtained from the iliac crest is frequently employed to perform spinal fusion. Osteogenic bone marrow stromal (a.k.a. mesenchymal stem) cells (BMSCs) are believed to be responsible for new bone formation and development of the bridging bone during spinal fusion, as these cells are located in both the graft and at the site of fusion. Our previous work revealed the importance of mitochondrial oxidative metabolism in osteogenic differentiation of BMSCs. Our objective here was to determine the impact of BMSC oxidative metabolism on osseointegration of the graft during spinal fusion. The first part of the study was focused on correlating oxidative metabolism in bone graft BMSCs to radiographic outcomes of spinal fusion in human patients. The second part of the study was focused on mechanistically proving the role of BMSC oxidative metabolism in osseointegration during spinal fusion using a genetic mouse model. Patients’ iliac crest-derived graft BMSCs were identified by surface markers. Mitochondrial oxidative function was detected in BMSCs with the potentiometric probe, CMXRos. Spinal fusion radiographic outcomes, determined by the Lenke grade, were correlated to CMXRos signal in BMSCs. A genetic model of high oxidative metabolism, cyclophilin D knockout (CypD KO), was used to perform spinal fusion in mice. Graft osseointegration in mice was assessed with micro-computed tomography. Our study revealed that higher CMXRos signal in patients’ BMSCs correlated with a higher Lenke grade. Mice with higher oxidative metabolism (CypD KO) had greater mineralization of the spinal fusion bridge, as compared to the control mice. We therefore conclude that higher oxidative metabolism in BMSCs correlates with better spinal fusion outcomes in both human patients and in a mouse model. Altogether, our study suggests that promoting oxidative metabolism in osteogenic cells could improve spinal fusion outcomes for patients.

Does Rheumatoid Arthritis Affect the Infection and Complications Rates of Spinal Surgery? A Systematic Review and Meta-Analysis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that produces synovial membrane inflammation and causes progressive articular damage with function loss. Some controversy exists regarding whether RA is associated with infection and complications after spinal surgery. The present study aimed to determine the effect of RA on spinal surgery infection and complications.

METHODS

A systematic literature search was performed in accordance with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines. All studies that had compared patients who had undergone spinal surgery with and without RA were included in the analysis.

RESULTS

We found significantly greater rates statistically of complications (odds ratio [OR], 1.43; 95% confidence interval [CI], 1.20-1.70; P < 0.05) and infections (OR, 1.69; 95% CI, 1.46-1.95, P < 0.05) in those with RA than in those without RA after spinal surgery. When registry data were excluded, the results suggested that the incidence of complications (OR, 2.24; 95% CI, 0.92-5.44; P = 0.08) and infections (OR, 1.76; 95% CI, 1.50-2.07; P < 0.05) was still greater for the RA group than for the non-RA group.

CONCLUSION

When undergoing spinal surgery, patients with RA have a greater risk of operative complications and infection. Surgeons should be aware of these risks and appropriately plan spinal operation for patients with RA to reduce the risk of complications.

Surgical Management of the Lumbar Spine in Rheumatoid Arthritis

STUDY DESIGN

Narrative review.

OBJECTIVE

To provide an overview on the diagnosis and surgical management of rheumatoid involvement of the lumbar spine. Rheumatoid arthritis (RA) is a chronic inflammatory disease of synovial joints, most commonly appendicular followed by axial. Although cervical spine involvement of RA is well documented, data on lumbar spine involvement and surgical management remains limited.

METHODS

Using PubMed, studies published prior to November 2018 with the keywords "RA, etiology"; "RA, spine management"; "RA, surgical management"; "RA, treatment"; "RA, DMARDs"; "RA, lumbar spine"; "RA, spine surgical outcomes"; "RA, imaging" were evaluated.

RESULTS

The narrative review addresses the epidemiology, manifestations, imaging, surgical complications, and operative and nonoperative management of RA involvement of the lumbar spine.

CONCLUSIONS

Rheumatoid involvement of the lumbar spine can present with lower back pain, neurogenic claudication, radiculopathy, spinal deformity, and instability. Patients with RA have significantly higher rates of vertebral fractures and complications following surgical intervention. However, in the setting of instability and spinal deformity, thoughtful surgical planning in conjunction with optimal medical management is recommended.

Risk prediction of degenerative scoliosis combined with lumbar spinal stenosis in patients with rheumatoid arthritis: a case-control study

The purpose of this study is to compare incidence of degenerative scoliosis (DS) in patients who diagnosed lumbar spinal stenosis (LSS) with or without rheumatoid arthritis (RA) and identify the risk factors of DS severity in RA patients. 61 LSS patients with RA (RA group) and 87 demographic-matched LSS patients without RA (NoRA group) from January 2013 to April 2018 were enrolled. The extracted information includes RA-related parameters such as Steinbrocker classification, disease-modifying anti-rheumatic drugs (DMARDs), and DS-related information such as Cobb angle, apical vertebra, along with osteoporosis and history of total knee arthroplasty (TKA). Comparisons between RA and NoRA group and between DS and non-DS subgroup with RA were performed, as well as the risk factors on DS severity in RA patients. The incidence of DS in RA group was 42.6%, larger than that of NoRA group (P = 0.002). The mean Cobb angle between the two groups was of no difference (P = 0.076). The apical vertebrae were both mainly focused on L3 and L4 vertebrae in both groups with no significant difference on the distribution of apical vertebrae (P = 0.786). Female took a larger proportion in DS subgroup than that of NoDS subgroup in patients with RA (P = 0.039), while Steinbrocker classification was irrelevant to the occurrence of DS and Cobb angle. Multiple regression analysis showed that TKA was a risk factor for the severity of Cobb angle (P = 0.040). The incidence of DS in LSS patients with RA is higher than non-RA patients. RA patients performed TKA sustained less severity of DS.

Perioperative outcomes associated with thoracolumbar 3-column osteotomies for adult spinal deformity patients with rheumatoid arthritis

OBJECTIVE

Spinal deformity causing spinal imbalance is directly correlated to pain and disability. Prior studies suggest adult spinal deformity (ASD) patients with rheumatoid arthritis (RA) have more complex deformities and are at higher risk for complications. In this study the authors compared outcomes of ASD patients with RA following thoracolumbar 3-column osteotomies to outcomes of a matched control cohort.

METHODS

All patients with RA who underwent 3-column osteotomy for thoracolumbar deformity correction performed by the senior author from 2006 to 2016 were identified retrospectively. A cohort of patients without RA who underwent 3-column osteotomies for deformity correction was matched based on multiple clinical factors. Data regarding demographics and surgical approach, along with endpoints including perioperative outcomes, reoperations, and incidence of proximal junctional kyphosis (PJK) were reviewed. Univariate analyses were used to compare patients with RA to matched controls.

RESULTS

Eighteen ASD patients with RA were identified, and a matched cohort of 217 patients was generated. With regard to patients with RA, 11.1% were male and the mean age was 68.1 years. Vertebral column resection (VCR) was performed in 22.2% and pedicle subtraction osteotomy (PSO) in 77.8% of patients. Mean case length was 324.4 minutes and estimated blood loss (EBL) was 2053.6 ml. Complications were observed in 38.9% of patients with RA and 29.0% of patients without RA (p = 0.380), with a trend toward increased medical complications (38.9% vs 21.2%, p = 0.084). Patients with RA had a significantly higher incidence of deep vein thrombosis (DVT)/pulmonary embolism (PE) (11.1% vs 1.8%, p = 0.017) and wound infections (16.7% vs 5.1%, p = 0.046). PJK occurred in 16.7% of patients with RA, and 33.3% of RA patients underwent reoperation. Incidence rates of PJK and reoperation in matched controls were 12.9% and 25.3%, respectively (p = 0.373, p = 0.458). At follow-up, mean sagittal vertical axis (SVA) was 6.1 cm in patients with RA and 4.5 cm in matched controls (p = 0.206).

CONCLUSIONS

Findings from this study suggest that RA patients experience a higher incidence of medical complications, specifically DVT/PE. Preoperative lower-extremity ultrasounds, inferior vena cava (IVC) filter placement, and/or early initiation of DVT prophylaxis in RA patients may be indicated. Perioperative complications, morbidity, and long-term outcomes are otherwise similar to non-RA patients.

Comparison of adult spinal deformity patients with and without rheumatoid arthritis undergoing primary non-cervical spinal fusion surgery: a nationwide analysis of 52,818 patients

BACKGROUND CONTEXT

Numerous studies have analyzed the impact of rheumatoid arthritis (RA) on the cervical spine and its related surgical interventions. However, there is a paucity of literature available conducting the same analyses in patients with non-cervical spine involvement.

PURPOSE

The objective of this study was to compare patient characteristics, comorbidities, and complications in patients with and without RA undergoing primary non-cervical spinal fusions.

STUDY DESIGN/SETTING

This is a retrospective national database review.

PATIENT SAMPLE

A total of 52,818 patients with adult spinal deformity undergoing non-cervical spinal fusions (1,814 patients with RA and 51,004 patients without RA).

OUTCOME MEASURES

The outcome measures in the study include patient characteristics, as well as complication and mortality rates.

MATERIALS AND METHODS

Using the Nationwide Inpatient Sample from 2003 to 2014, International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes were used to identify patients aged ≥18 years old with and without RA undergoing primary non-cervical spinal fusions. Univariate analysis was used to determine patient characteristics, comorbidities, and complication values for each group. Bivariate analysis was used to compare the two groups. Significance was set at p<.05.

RESULTS

Patients with RA were older (p<.001), were more likely to be women (p<.001), had increased rates of osteoporosis (p<.001), had a greater percentage of their surgeries reimbursed by Medicare (p<.001), and more often had weekend admissions (p=.014). There was no difference in all the other characteristics. Patients with RA had higher rates of iron deficiency anemia, congestive heart failure, chronic pulmonary disease, depression, and fluid and electrolyte disorders (all, p<.001). Patients without RA had higher rates of alcohol abuse (p=.027). There was no difference in all the other complications. There was no difference in mortality rate (p=.99). Total complications were greater in patients with RA (p<.001). Patients with RA had higher rates of infection (p=.032), implant-related complications (p=.010), incidental durotomies (p=.001), and urinary tract infections (p<.001). No difference existed among the other complications.

CONCLUSIONS

Patients with RA have an increased number of comorbidities and complication rates compared with patients without RA. Such knowledge can help surgeons and patients with RA have beneficial preoperative discussions regarding outcomes.

Rheumatoid Arthritis Is Associated With an Increased Risk of Postoperative Infection and Revision Surgery in Elderly Patients Undergoing Anterior Cervical Fusion

STUDY DESIGN

Retrospective review.

OBJECTIVE

To identify the incidence and analyze the risk of postoperative complications amongst elderly patients with rheumatoid arthritis undergoing anterior cervical fusion.

SUMMARY OF BACKGROUND DATA

Previous studies have reported elevated risks of postoperative complications for patients with rheumatoid arthritis undergoing orthopedic procedures. However, little is known about the risk of postoperative complications in rheumatoid arthritis patients after spine surgery.

METHODS

A commercially available database was queried for all Medicare patients 65 years of age and older undergoing one- or two-level primary anterior cervical fusion surgeries from 2005 to 2013. Complications, hospitalization costs, and length of stay were queried. Multivariate logistic regression analyses were performed to estimate the odds ratio for each complication adjusted for age, sex, and Charlson Comorbidity Index.

RESULTS

A total of 6067 patients with a history of rheumatoid arthritis and 113,187 controls were identified. Significantly higher incidences of major medical complications (7.5% vs. 5.9%, P < 0.001), postoperative infections (2.6% vs. 1.5%, P < 0.001), and revision surgery (1.1% vs. 0.6%, P < 0.001) were observed amongst the rheumatoid arthritis cohort. Significantly greater average cost of hospitalization ($17,622 vs. $12,489, P < 0.001) and average length of stay (3.13 vs. 2.08 days, P < 0.001) were also observed.

CONCLUSION

Patients with rheumatoid arthritis undergoing anterior cervical fusion face increased risks of postoperative infection and revision surgery compared to normal controls. This information is valuable for preoperative counseling and risk stratification.

LEVEL OF EVIDENCE

3.

Incidence and risk factors of wound complications in long segment instrumented thoracolumbar spinal fusions: a retrospective study

BACKGROUND

This is a retrospective analysis of prospectively collected data. Our objective was to determine the incidence and assess the risk factors associated with surgical site wound complications in long segment (7+ vertebrae) instrumented thoracolumbar fusions. Surgical site complications lead to patient morbidity, increased financial burden, and further medical intervention. Risk factors for wound complications in spinal surgery include patient factors such as obesity and diabetes, and surgical factors such as operative time and procedure type. Fusion with instrumentation is one of the strongest associated risk factors in the literature.

METHODS

A comprehensive search of the National Surgical Quality Improvement Program (NSQIP) from 2005 to 2014 was performed, selecting cases based on Current Procedural Terminology (CPT) codes. Cases were then stratified based on the presence of one of the following wound complications: superficial surgical site infection, deep surgical site infection, organ space infection, and wound dehiscence. Univariate and bivariate analyses were performed to determine risk factors.

RESULTS

A total of 2,548 cases were identified, and the most common diagnoses were scoliosis (29%), spondylosis (17%) and spinal stenosis (14%). Overall, 4.24% of cases had at least one wound complication. Identified risk factors include obesity, preoperative transfusion, preoperative wound infection, and operative time. Associated outcomes include stroke with neurological deficit, perioperative transfusion, deep vein thrombosis (DVT), sepsis, septic shock, readmission, reoperation, and longer length of hospital stay. Many of these variables are independently associated with a wound complication.

CONCLUSIONS

Our analysis of the NSQIP demonstrated risk factors and complications associated with wound infections in the setting of long segment fusions (7+ levels). These findings may aid surgeons in determining a patient's risk of developing a wound complication, with the goal of lessening the associated morbidity and economic burden.

Risk factors for revision surgery following primary adult spinal deformity surgery in patients 65 years and older

OBJECTIVE Surgical correction of adult spinal deformity (ASD) is a complex undertaking with high revision rates. The elderly population is poorly studied with regard to revision surgery, yet senior citizens constitute a rapidly expanding surgical demographic. Previous studies aimed at elucidating appropriate risk factors for revision surgery have been limited by small cohort sizes. The purpose of this study was to assess factors that modify the risk of revision surgery in elderly patients with ASD. METHODS The PearlDiver database (2005-2012) was used to determine revision rates in elderly ASD patients treated with a primary thoracolumbar posterolateral fusion of 8 or more levels. Analyzed risk factors included demographics, comorbid conditions, and surgical factors. Significant univariate predictors were further analyzed with multivariate analysis. The causes of revision at each year of follow-up were determined. RESULTS A total of 2293 patients who had been treated with posterolateral fusion of 8 or more levels were identified. At the 1-year follow-up, 241 (10.5%) patients had been treated with revision surgery, while 424 (18.5%) had revision surgery within 5 years. On univariate analysis, obesity was found to be a significant predictor of revision surgery at 1 year, while bone morphogenetic protein (BMP) use was found to significantly decrease revision surgery at 4 and 5 years of followup. Diabetes mellitus, osteoporosis, and smoking history were all significant univariate predictors of increased revision risk at multiple years of follow-up. Multivariate analysis at 5 years of follow-up revealed that osteoporosis (OR 1.98, 95% CI 1.60-2.46, p < 0.0001) and BMP use (OR 0.70, 95% CI 0.56-0.88, p = 0.002) were significantly associated with an increased and decreased revision risk, respectively. Smoking history trended toward significance (OR 1.37, 95% CI 1.10-1.70, p = 0.005). Instrument failure was consistently the most commonly cited reason for revision. Five years following surgery, it was estimated that the cohort had 68.8% survivorship. CONCLUSIONS For elderly patients with ASD, osteoporosis increases the risk of revision surgery, while BMP use decreases the risk. Other comorbidities were not found to be significant predictors of long-term revision rates. It is expected that within 5 years following the index procedure, over 30% of patients will require revision surgery.