✓ Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease that primarily affects the vertebral column and sacroiliac joints. Over time, the disease process promotes extensive remodeling of the spinal axis via ligamentous ossification, vertebral joint fusion, osteoporosis, and kyphosis. These pathological changes result in a weakened vertebral column with increased susceptibility to fractures and spinal cord injury (SCI). Spinal cord injury is often exacerbated by the highly unstable nature of vertebral column fractures in AS. A high incidence of missed fractures in the ankylosed spine as well as an increased incidence of spinal epidural hematoma also worsens the severity of SCI. Spinal cord injury in AS is a complex problem associated with high morbidity and mortality rates, which can be attributed to the severity of the injury, associated medical comorbidities, and the advanced age of most patients with AS who suffer an SCI. In this paper the authors outline the factors that increase the incidence of vertebral column fractures and SCI in AS and discuss the management of SCI in patients with AS. Primary prevention strategies for SCI in patients with AS are outlined as well.
W. Bradley Jacobs and Michael G. Fehlings
W. Bradley Jacobs, Richard J. Bransford, Carlo Bellabarba, and Jens R. Chapman
Charcot spinal arthropathy (CSA) is an uncommon disorder that occurs in the setting of conditions with decreased protective sensation of the vertebral column, resulting in vertebral joint degeneration, pain, and deformity. Historically, CSA treatment has been fraught with high failure rates. Over time, the authors' institution has trended toward a CSA treatment paradigm of intralesional debridement, circumferential fusion, and four-rod lumbopelvic fixation. As such, the overall objectives of this study were to define the specific clinical characteristics of this rare condition and to determine whether the authors' treatment paradigm has decreased the incidence of revision due to hardware failure/presumed pseudarthrosis or the development of a new CSA over the course of the study and in comparison with historical controls.
The authors performed a retrospective review of the clinical and radiographic records for all patients with CSA treated by the Spine Service at the University of Washington between 1997 and 2009.
Twenty-three patients with CSA were identified. The mean age at presentation was 43.1 years, and the mean latency between spinal cord injury and CSA diagnosis was 19.6 years. The mean follow-up was 33.1 months. Pain and progressive deformity were the major presenting symptoms. Concomitant infection was identified in 17% of patients. Patients with CSA were noted to have long initial fusion constructs spanning an average of 8.4 vertebral levels. Charcot spinal arthropathy did not occur above the level of neurological injury. The vast majority of CSA cases occurred caudally along the spinal axis, with 65% occurring within 1 level of the caudal end of the index fusion construct and 35% occurring even farther distally. Revision due to hardware failure or the development of a new CSA level occurred in 35% of patients. Rates of treatment failure requiring revision significantly decreased over the course of the study, with revision occurring in 6 (66%) of 9 patients who underwent surgery before 2002, in comparison with only 2 (14%) of 14 treated between 2002 and 2009. During a mean follow-up period of 34 months, no treatment revision occurred in the subgroup of 9 patients who underwent four-rod lumbopelvic fixation.
This study represents the largest reported modern surgical series of CSA patients. While revision rates were initially high and comparable to previous reports, the authors' multimodal treatment paradigm, which includes the use of bone morphogenetic protein and four-rod lumbopelvic fixation, dramatically reduced the incidence of treatment failure requiring revision over the course of the study period and represents a significant improvement in the treatment of CSA.
W. Bradley Jacobs and Richard G. Perrin
Metastases to the spine are a common and somber manifestation of systemic neoplasia. The incidence of spinal metastases continues to increase, likely a result of increasing survival times for patients with cancer. Historically, surgery for spinal metastases has consisted of simple decompressive laminectomy. Results obtained in retrospective case series, however, have shown that this treatment provides little benefit to the patient. With the advent of better patient-related selection practices, in conjunction with new surgical techniques and improved postoperative care, the ability of surgical therapy to play an important and beneficial role in the multidisciplinary care of cancer patients with spinal disease has improved significantly. Controversy remains, however, with respect to the relative merits of surgery, radiotherapy, chemotherapy, or a combination of these treatments.
In this topic review, the literature on spinal column and spinal cord metastases is collated to provide a description of the presentation, investigations, indications for surgical therapy, and the role of adjuvant cancer therapies for patients with spinal metastases. In addition, the authors discuss the different surgical strategies available in the armamentarium of the neurosurgeon treating patients with spinal metastasis.
Won Hyung A. Ryu, Michael M. H. Yang, Sandeep Muram, W. Bradley Jacobs, Steven Casha, and Jay Riva-Cambrin
As the cost of health care continues to increase, there is a growing emphasis on evaluating the relative economic value of treatment options to guide resource allocation. The objective of this systematic review was to evaluate the current evidence regarding the cost-effectiveness of cranial neurosurgery procedures.
The authors performed a systematic review of the literature using PubMed, EMBASE, and the Cochrane Library, focusing on themes of economic evaluation and cranial neurosurgery following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Included studies were publications of cost-effectiveness analysis or cost-utility analysis between 1995 and 2017 in which health utility outcomes in life years (LYs), quality-adjusted life years (QALYs), or disability-adjusted life years (DALYs) were used. Three independent reviewers conducted the study appraisal, data abstraction, and quality assessment, with differences resolved by consensus discussion.
In total, 3485 citations were reviewed, with 53 studies meeting the inclusion criteria. Of those, 34 studies were published in the last 5 years. The most common subspecialty focus was cerebrovascular (32%), followed by neurooncology (26%) and functional neurosurgery (24%). Twenty-eight (53%) studies, using a willingness to pay threshold of US$50,000 per QALY or LY, found a specific surgical treatment to be cost-effective. In addition, there were 11 (21%) studies that found a specific surgical option to be economically dominant (both cost saving and having superior outcome), including endovascular thrombectomy for acute ischemic stroke, epilepsy surgery for drug-refractory epilepsy, and endoscopic pituitary tumor resection.
There is an increasing number of cost-effectiveness studies in cranial neurosurgery, especially within the last 5 years. Although there are numerous procedures, such as endovascular thrombectomy for acute ischemic stroke, that have been conclusively proven to be cost-effective, there remain promising interventions in current practice that have yet to meet cost-effectiveness thresholds.
Presented at the 2019 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves
Michael M. H. Yang, Won Hyung A. Ryu, Steven Casha, Stephan DuPlessis, W. Bradley Jacobs, and R. John Hurlbert
Cervical disc arthroplasty (CDA) is an accepted motion-sparing technique associated with favorable patient outcomes. However, heterotopic ossification (HO) and adjacent-segment degeneration are poorly understood adverse events that can be observed after CDA. The purpose of this study was to retrospectively examine 1) the effect of the residual exposed endplate (REE) on HO, and 2) identify risk factors predicting radiographic adjacent-segment disease (rASD) in a consecutive cohort of CDA patients.
A retrospective cohort study was performed on consecutive adult patients (≥ 18 years) who underwent 1- or 2-level CDA at the University of Calgary between 2002 and 2015 with > 1-year follow-up. REE was calculated by subtracting the anteroposterior (AP) diameter of the arthroplasty device from the native AP endplate diameter measured on lateral radiographs. HO was graded using the McAfee classification (low grade, 0–2; high grade, 3 and 4). Change in AP endplate diameter over time was measured at the index and adjacent levels to indicate progressive rASD.
Forty-five patients (58 levels) underwent CDA during the study period. The mean age was 46 years (SD 10 years). Twenty-six patients (58%) were male. The median follow-up was 29 months (IQR 42 months). Thirty-three patients (73%) underwent 1-level CDA. High-grade HO developed at 19 levels (33%). The mean REE was 2.4 mm in the high-grade HO group and 1.6 mm in the low-grade HO group (p = 0.02). On multivariable analysis, patients with REE > 2 mm had a 4.5-times-higher odds of developing high-grade HO (p = 0.02) than patients with REE ≤ 2 mm. No significant relationship was observed between the type of artificial disc and the development of high-grade HO (p = 0.1). RASD was more likely to develop in the lower cervical spine (p = 0.001) and increased with time (p < 0.001). The presence of an artificial disc was highly protective against degenerative changes at the index level of operation (p < 0.001) but did not influence degeneration in the adjacent segments.
In patients undergoing CDA, high-grade HO was predicted by REE. Therefore, maximizing the implant-endplate interface may help to reduce high-grade HO and preserve motion. RASD increases in an obligatory manner following CDA and is highly linked to specific levels (e.g., C6–7) rather than the presence or absence of an adjacent arthroplasty device. The presence of an artificial disc is, however, protective against further degenerative change at the index level of operation.
Development and validation of a clinical prediction score for poor postoperative pain control following elective spine surgery
Presented at the 2020 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves
Michael M. H. Yang, Jay Riva-Cambrin, Jonathan Cunningham, Nathalie Jetté, Tolulope T. Sajobi, Alex Soroceanu, Peter Lewkonia, W. Bradley Jacobs, and Steven Casha
Thirty percent to sixty-four percent of patients experience poorly controlled pain following spine surgery, leading to patient dissatisfaction and poor outcomes. Identification of at-risk patients before surgery could facilitate patient education and personalized clinical care pathways to improve postoperative pain management. Accordingly, the aim of this study was to develop and internally validate a prediction score for poorly controlled postoperative pain in patients undergoing elective spine surgery.
A retrospective cohort study was performed in adult patients (≥ 18 years old) consecutively enrolled in the Canadian Spine Outcomes and Research Network registry. All patients underwent elective cervical or thoracolumbar spine surgery and were admitted to the hospital. Poorly controlled postoperative pain was defined as a mean numeric rating scale score for pain at rest of > 4 during the first 24 hours after surgery. Univariable analysis followed by multivariable logistic regression on 25 candidate variables, selected through a systematic review and expert consensus, was used to develop a prediction model using a random 70% sample of the data. The model was transformed into an eight-tier risk-based score that was further simplified into the three-tier Calgary Postoperative Pain After Spine Surgery (CAPPS) score to maximize clinical utility. The CAPPS score was validated using the remaining 30% of the data.
Overall, 57% of 1300 spine surgery patients experienced poorly controlled pain during the first 24 hours after surgery. Seven significant variables associated with poor pain control were incorporated into a prediction model: younger age, female sex, preoperative daily use of opioid medication, higher preoperative neck or back pain intensity, higher Patient Health Questionnaire–9 depression score, surgery involving ≥ 3 motion segments, and fusion surgery. Notably, minimally invasive surgery, body mass index, and revision surgery were not associated with poorly controlled pain. The model was discriminative (C-statistic 0.74, 95% CI 0.71–0.77) and calibrated (Hosmer-Lemeshow goodness-of-fit, p = 0.99) at predicting the outcome. Low-, high-, and extreme-risk groups stratified using the CAPPS score had 32%, 63%, and 85% predicted probability of experiencing poorly controlled pain, respectively, which was mirrored closely by the observed incidence of 37%, 62%, and 81% in the validation cohort.
Inadequate pain control is common after spine surgery. The internally validated CAPPS score based on 7 easily acquired variables accurately predicted the probability of experiencing poorly controlled pain after spine surgery.
Nathan Evaniew, David W. Cadotte, Nicolas Dea, Christopher S. Bailey, Sean D. Christie, Charles G. Fisher, Jerome Paquet, Alex Soroceanu, Kenneth C. Thomas, Y. Raja Rampersaud, Neil A. Manson, Michael Johnson, Andrew Nataraj, Hamilton Hall, Greg McIntosh, and W. Bradley Jacobs
Recently identified prognostic variables among patients undergoing surgery for cervical spondylotic myelopathy (CSM) are limited to two large international data sets. To optimally inform shared clinical decision-making, the authors evaluated which preoperative clinical factors are significantly associated with improvement on the modified Japanese Orthopaedic Association (mJOA) scale by at least the minimum clinically important difference (MCID) 12 months after surgery, among patients from the Canadian Spine Outcomes and Research Network (CSORN).
The authors performed an observational cohort study with data that were prospectively collected from CSM patients at 7 centers between 2015 and 2017. Candidate variables were tested using univariable and multiple binomial logistic regression, and multiple sensitivity analyses were performed to test assumptions about the nature of the statistical models. Validated mJOA MCIDs were implemented that varied according to baseline CSM severity.
Among 205 patients with CSM, there were 64 (31%) classified as mild, 86 (42%) as moderate, and 55 (27%) as severe. Overall, 52% of patients achieved MCID and the mean change in mJOA score at 12 months after surgery was 1.7 ± 2.6 points (p < 0.01), but the subgroup of patients with mild CSM did not significantly improve (mean change 0.1 ± 1.9 points, p = 0.8). Univariate analyses failed to identify significant associations between achieving MCID and sex, BMI, living status, education, smoking, disability claims, or number of comorbidities. After adjustment for potential confounders, the odds of achieving MCID were significantly reduced with older age (OR 0.7 per decade, 95% CI 0.5–0.9, p < 0.01) and higher baseline mJOA score (OR 0.8 per point, 95% CI 0.7–0.9, p < 0.01). The effects of symptom duration (OR 1.0 per additional month, 95% CI 0.9–1.0, p = 0.2) and smoking (OR 0.4, 95% CI 0.2–1.0, p = 0.06) were not statistically significant.
Surgery is effective at halting the progression of functional decline with CSM, and approximately half of all patients achieve the MCID. Data from the CSORN confirmed that older age is independently associated with poorer outcomes, but novel findings include that patients with milder CSM did not experience meaningful improvement, and that symptom duration and smoking were not important. These findings support a nuanced approach to shared decision-making that acknowledges some prognostic uncertainty when weighing the various risks, benefits, and alternatives to surgical treatment.
Raphaële Charest-Morin, Christopher S. Bailey, Greg McIntosh, Y. Raja Rampersaud, W. Bradley Jacobs, David W. Cadotte, Jérome Paquet, Hamilton Hall, Michael H. Weber, Michael G. Johnson, Andrew Nataraj, Najmedden Attabib, Neil Manson, Philippe Phan, Sean D. Christie, Kenneth C. Thomas, Charles G. Fisher, and Nicolas Dea
In multilevel posterior cervical instrumented fusion, extension of fusion across the cervicothoracic junction (CTJ) at T1 or T2 has been associated with decreased rates of reoperation and pseudarthrosis but with longer surgical time and increased blood loss. The impact on patient-reported outcomes (PROs) remains unclear. The primary objective was to determine whether extension of fusion through the CTJ influenced PROs at 3, 12, and 24 months after surgery. The secondary objective was to compare the number of patients who reached the minimal clinically important differences (MCIDs) for the PROs, modified Japanese Orthopaedic Association (mJOA) score, operative time, intraoperative blood loss, length of stay, discharge disposition, adverse events (AEs), reoperation within 24 months of surgery, and patient satisfaction.
This was a retrospective observational cohort study of prospectively collected multicenter data of patients with degenerative cervical myelopathy. Patients who underwent posterior instrumented fusion of 4 levels or greater (between C2 and T2) between January 2015 and October 2020 and received 24 months of follow-up were included. PROs (scores on the Neck Disability Index [NDI], EQ-5D, physical component summary and mental component summary of SF-12, and numeric rating scale for arm and neck pain) and mJOA scores were compared using ANCOVA and adjusted for baseline differences. Patient demographic characteristics, comorbidities, and surgical details were abstracted. The proportions of patients who reached the MCIDs for these outcomes were compared with the chi-square test. Operative duration, intraoperative blood loss, AEs, reoperation, discharge disposition, length of stay, and satisfaction was compared by using the chi-square test for categorical variables and the independent-samples t-test for continuous variables.
A total of 198 patients were included in this study (101 patients with fusion not crossing the CTJ and 97 with fusion crossing the CTJ). Patients with a construct extending through the CTJ were more likely to be female and have worse baseline NDI scores (p > 0.05). When adjusted for baseline differences, there were no statistically significant differences between the two groups in terms of the PROs and mJOA scores at 3, 12, and 24 months. Surgical duration was longer (p < 0.001) and intraoperative blood loss was greater in the group with fusion extending to the upper thoracic spine (p = 0.013). There were no significant differences between groups in terms of AEs (p > 0.05). Fusion with a construct crossing the CTJ was associated with reoperation (p = 0.04). Satisfaction with surgery was not significantly different between groups. The proportions of patients who reached the MCIDs for the PROs were not statistically different at any time point.
There were no statistically significant differences in PROs between patients with a posterior construct extending to the upper thoracic spine and those without such extension for as long as 24 months after surgery. The AE profiles were not significantly different, but longer surgical time and increased blood loss were associated with constructs extending across the CTJ.
Lior M. Elkaim, Greg McIntosh, Nicolas Dea, Rodrigo Navarro-Ramirez, W. Bradley Jacobs, David W. Cadotte, Supriya Singh, Sean D. Christie, Aaron Robichaud, Philippe Phan, Jérôme Paquet, Andrew Nataraj, Hamilton Hall, Christopher S. Bailey, Y. Raja Rampersaud, Kenneth Thomas, Neil Manson, Charles Fisher, and Michael H. Weber
Degenerative cervical myelopathy (DCM) is an important public health issue. Surgery is the mainstay of treatment for moderate and severe DCM. Delayed discharge of patients after DCM surgery is associated with increased healthcare costs. There is a paucity of data regarding predictive factors for discharge destination after scheduled surgery for patients with DCM. The purpose of this study was to identify factors predictive of home versus nonhome discharge after DCM surgery.
Patients undergoing scheduled DCM surgery who had been enrolled in a prospective DCM substudy of the Canadian Spine Outcomes and Research Network registry between January 2015 and October 2020 were included in this retrospective analysis. Patient data were evaluated to identify potential factors predictive of home discharge after surgery. Logistic regression was used to identify independent factors predictive of home discharge. A multivariable model was then used as a final model.
Overall, 639 patients were included in the initial analysis, 543 (85%) of whom were discharged home. The mean age of the entire cohort was 60 years (SD 11.8 years), with a BMI of 28.9 (SD 5.7). Overall, 61.7% of the patients were female. The mean length of stay was 2.72 days (SD 1.7 days). The final internally validated bootstrapped multivariable model revealed that younger age, higher 9-Item Patient Health Questionnaire score, lower Neck Disability Index scores, fewer operated levels, mJOA scores indicating mild disease, anterior cervical discectomy and fusion procedure, and no perioperative adverse effects were predictive of home discharge.
Younger age, less neck-related disability, fewer operated levels, more significant depression, less severe myelopathy, anterior cervical discectomy and fusion procedure, and no perioperative adverse effects are predictive of home discharge after surgery for DCM. These factors can help to guide clinical decision-making and optimize postoperative care pathways.
Oliver G. S. Ayling, Raphaele Charest-Morin, Matthew E. Eagles, Tamir Ailon, John T. Street, Nicolas Dea, Greg McIntosh, Sean D. Christie, Edward Abraham, W. Bradley Jacobs, Christopher S. Bailey, Michael G. Johnson, Najmedden Attabib, Peter Jarzem, Michael Weber, Jerome Paquet, Joel Finkelstein, Alexandra Stratton, Hamilton Hall, Neil Manson, Y. Raja Rampersaud, Kenneth Thomas, and Charles G. Fisher
Previous works investigating rates of adverse events (AEs) in spine surgery have been retrospective, with data collection from administrative databases, and often from single centers. To date, there have been no prospective reports capturing AEs in spine surgery on a national level, with comparison among centers.
The Spine Adverse Events Severity system was used to define the incidence and severity of AEs after spine surgery by using data from the Canadian Spine Outcomes and Research Network (CSORN) prospective registry. Patient data were collected prospectively and during hospital admission for those undergoing elective spine surgery for degenerative conditions. The Spine Adverse Events Severity system defined minor and major AEs as grades 1–2 and 3–6, respectively.
There were 3533 patients enrolled in this cohort. There were 85 (2.4%) individual patients with at least one major AE and 680 (19.2%) individual patients with at least one minor AE. There were 25 individual patients with 28 major intraoperative AEs and 260 patients with 275 minor intraoperative AEs. Postoperatively there were 61 patients with a total of 80 major AEs. Of the 487 patients with minor AEs postoperatively there were 698 total AEs. The average enrollment was 321 patients (range 47–1237 patients) per site. The rate of major AEs was consistent among sites (mean 2.9% ± 2.4%, range 0%–9.1%). However, the rate of minor AEs varied widely among sites—from 7.9% to 42.5%, with a mean of 18.8% ± 9.7%. The rate of minor AEs varied depending on how they were reported, with surgeon reporting associated with the lowest rates (p < 0.01).
The rate of major AEs after lumbar spine surgery is consistent among different sites but the rate of minor AEs appears to vary substantially. The method by which AEs are reported impacts the rate of minor AEs. These data have implications for the detection and reporting of AEs and the design of strategies aimed at mitigating complications.