✓ The authors report a case in which the lateral C-1 arch fractured in a patient with rheumatoid arthritis and an intact fusion mass; this patient had previously undergone a C1–2 Brooks-type fusion. This unique complication occurred secondary to continued resorption of the C1–2 rheumatoid pannus. Two years after occipitocervical fusion the patient has made a complete neurological recovery.
Symptomatic C1–2 fusion failure due to a fracture of the lateral C-1 posterior arch in a patient with rheumatoid arthritis
Case report and review of the literature
Robert D. Ecker, Mark B. Dekutoski and Michael J. Ebersold
Paul C. McCormick
Michelle J. Clarke, Robert D. Ecker, William E. Krauss, Robyn L. McClelland and Mark B. Dekutoski
The cervical foraminotomy was pioneered in the 1940s to address radicular symptoms via a posterior approach, but the long-term outcome has not been adequately studied.
The authors retrospectively analyzed data obtained from 303 patients (188 male and 115 female, mean age 49.2 years) who had consecutively undergone a single-level posterior foraminotomy for cervical radiculopathy between 1972 and 1992. The median follow-up duration was 7.1 years. The major end point studied was the development of symptomatic adjacent- or same-segment disease. Incidence rates per 1000 person-years were calculated, and the natural history of the disease was predicted using Kaplan–Meier survivorship analysis.
In 15 (4.9%) of 303 patients, symptomatic adjacent-segment disease developed, yielding a rate of 6.4/1000 person-years at risk. This included nine (2.9%) of 303 patients requiring reoperation, yielding a rate of 3.8/1000 person-years. Kaplan–Meier survivorship analysis suggested a relatively stable annual 0.7% rate for developing adjacent-segment disease, with a 10-year rate of 6.7%. Ten patients developed same-segment disease, yielding a risk rate of 3.9/1000 person-years.
Kaplan–Meier survivorship analysis demonstrated a 5- and 10-year risk rate of developing same-segment disease of 3.2 and 5.0%, respectively.
Although additional study is needed, analysis of the present data suggests that posterior foraminotomy is associated with a low rate of same- and adjacent-segment disease.
Aaron A. Cohen-Gadol, Mark B. Dekutoski, Choll W. Kim, Lynn M. Quast and William E. Krauss
Object. The AO Universal Spine System thoracic pedicle hook design includes a fixation screw that passes obliquely through the inferior facet into the pedicle to engage in the posterior portion of the superior vertebral body endplate. This endplate screw provides additional purchase at the hook—bone interface. To determine the safety of this fixation system the authors reviewed the operative notes, radiographs, and outcomes of patients who underwent placement of endplate screws.
Methods. Thirty-six patients (16 male and 20 female patients) who required posterior thoracic instrumentation for spinal deformity (11 cases), neoplasm (15 cases), and traumatic injury (10 cases) were included in this study.
One hundred sixty-four endplate screws were placed (mean 4.3/patient) to augment pedicle hooks for posterior thoracic instrumentation. The number of instrumented levels ranged from seven to 16. The positions of the screws in relation to the pedicle, neural foramen, spinal canal, and endplate were evaluated by assessing plain radiographs and computerized tomography scans (10 cases). Eighty-two screws (56%) were in ideal position. Lateral pedicle wall perforation occurred with 51 screws (35%). Three screws violated the medial wall and nine screws violated the superior or inferior walls of the pedicle. There were no clinical sequelae associated with any of the malpositioned screws. Adequate follow-up radiographic data were not available in five patients. The mean follow-up duration was 19.8 months (range 3–61 months).
Two patients required revision surgery at 3 months and 18 months, respectively, because of hook/endplate screw displacement. There was also one case of an endplate screw fracture without hook displacement that was discovered during subsequent revision surgery. The remainder of the endplate screws and associated pedicles hooks maintained their original positions. There was no case of spinal cord, nerve root, pulmonary, or vascular injury.
Conclusions. The placement of supplemental endplate screws in conjunction with thoracic pedicle hooks can be conducted safely.
Daniel M. Sciubba, Rory J. Petteys, Mark B. Dekutoski, Charles G. Fisher, Michael G. Fehlings, Stephen L. Ondra, Laurence D. Rhines and Ziya L. Gokaslan
With continued growth of the elderly population and improvements in cancer therapies, the number of patients with symptomatic spinal metastases is likely to increase, and this is a condition that commonly leads to debilitating neurological dysfunction and pain. Advancements in surgical techniques of resection and spinal reconstruction, improvements in clinical outcomes following various treatment modalities, generally increased overall survival in patients with metastatic spine disease, and a recent randomized trial by Patchell and colleagues demonstrating the superiority of a combined surgical/radiotherapeutic approach over a radiotherapy-only strategy have led many to suggest increasingly aggressive interventions for patients with such lesions. Optimal management of spinal metastases encompasses numerous medical specialties, including neurosurgery, orthopedic surgery, medical and radiation oncology, radiology, and rehabilitation medicine. In this review, the clinical presentation, diagnosis, and management of spinal metastatic disease are discussed. Ultimately, the goal of treatment in patients with spinal metastases remains palliative, and clinical judgment is required to select the appropriate patients for surgical intervention.
Anne L. Versteeg, Nicolas Dea, Stefano Boriani, Peter P. Varga, Alessandro Luzzati, Michael G. Fehlings, Mark H. Bilsky, Laurence D. Rhines, Jeremy J. Reynolds, Mark. B. Dekutoski, Ziya L. Gokaslan, Niccole M. Germscheid and Charles G. Fisher
Osteoblastoma is a rare primary benign bone tumor with a predilection for the spinal column. Although of benign origin, osteoblastomas tend to behave more aggressively clinically than other benign tumors. Because of the low incidence of osteoblastomas, evidence-based treatment guidelines and high-quality research are lacking, which has resulted in inconsistent treatment. The goal of this study was to determine whether application of the Enneking classification in the management of spinal osteoblastomas influences local recurrence and survival time.
A multicenter database of patients who underwent surgical intervention for spinal osteoblastoma was developed by the AOSpine Knowledge Forum Tumor. Patient data pertaining to demographics, diagnosis, treatment, cross-sectional survival, and local recurrence were collected. Patients in 2 cohorts, based on the Enneking classification of the tumor (Enneking appropriate [EA] and Enneking inappropriate [EI]), were analyzed. If the final pathology margin matched the Enneking-recommended surgical margin, the tumor was classified as EA; if not, it was classified as EI.
A total of 102 patients diagnosed with a spinal osteoblastoma were identified between November 1991 and June 2012. Twenty-nine patients were omitted from the analysis because of short follow-up time, incomplete survival data, or invalid staging, which left 73 patients for the final analysis. Thirteen (18%) patients suffered a local recurrence, and 6 (8%) patients died during the study period. Local recurrence was strongly associated with mortality (relative risk 9.2; p = 0.008). When adjusted for Enneking appropriateness, this result was not altered significantly. No significant differences were found between the EA and EI groups in regard to local recurrence and mortality.
In this evaluation of the largest multicenter cohort of spinal osteoblastomas, local recurrence was found to be strongly associated with mortality. Application of the Enneking classification as a treatment guide for preventing local recurrence was not validated.
Dean Chou, Mark H. Bilsky, Alessandro Luzzati, Charles G. Fisher, Ziya L. Gokaslan, Laurence D. Rhines, Mark B. Dekutoski, Michael G. Fehlings, Ravi Ghag, Peter Varga, Stefano Boriani, Niccole M. Germscheid, Jeremy J. Reynolds and the AOSpine Knowledge Forum Tumor
Malignant peripheral nerve sheath tumors (MPNSTs) are rare soft-tissue sarcomas. Resection is the mainstay of treatment and the most important prognostic factor. However, complete resection of spinal MPNSTs with tumor-free margins is challenging due to the likelihood of residual tumor cells. The objective of this study was to describe whether the type of Enneking resection in the management of spinal MPNSTs had an effect on local recurrence and survival.
The AOSpine Knowledge Forum Tumor developed a multicenter database that includes demographic, diagnostic, therapeutic, local recurrence, and survival data on patients with primary spinal column tumors. Patients who had undergone surgery for a primary spinal MPNST were included and were analyzed in 2 groups: 1) those undergoing Enneking appropriate (EA) resections and 2) those undergoing Enneking inappropriate (EI) resections. EA surgery was performed if there was histopathological evidence of an intact tumor pseudocapsule and at least a marginal resection on a vital structure. EI surgery was performed if there was an intentional or inadvertent transgression of the margin.
Between 1993 and 2012, 29 primary spine MPNSTs were identified in 12 (41%) females and 17 (59%) males with a mean age at diagnosis of 40 ± 17 years (range 5–74 years). The median patient follow-up was 1.3 years (range 42 days to 11.2 years). In total, 14 (48%) patients died and 14 (48%) patients suffered a local recurrence, 10 (71%) of whom died. Within 2 years after surgery, the median survival and local recurrence were not achieved. Data about Enneking appropriateness of surgery were available for 27 patients; 9 (33%) underwent an EA procedure and 18 (67%) underwent an EI procedure. Enneking appropriateness did not have a significant influence on local recurrence or survival. Twenty-two patients underwent adjuvant treatment with combined chemo- and radiotherapy (n = 7), chemotherapy alone (n = 3), or radiotherapy alone (n = 12). Adjuvant therapy had no significant influence on recurrence or survival.
The rates of recurrence and survival were similar for spinal MPNSTs regardless of whether patients had an EA or EI resection or received adjuvant therapy. Other factors such as variability of pathologist interpretation, PET CT correlation, or neurofibromatosis Type 1 status may play a role in patient outcome. Nonetheless, MPNSTs should still be treated as sarcomas until further evidence is known. The authors recommend an individualized approach with careful multidisciplinary decision making, and the patient should be informed about the morbidity of en bloc surgery when considering MPNST resection.
Charles G. Fisher, Tony Goldschlager, Stefano Boriani, Peter Paul Varga, Laurence D. Rhines, Michael G. Fehlings, Alessandro Luzzati, Mark B. Dekutoski, Jeremy J. Reynolds, Dean Chou, Sigurd H. Berven, Richard P. Williams, Nasir A. Quraishi, Chetan Bettegowda and Ziya L. Gokaslan
The National Institutes of Health recommends strategies to obtain evidence for the treatment of rare conditions such as primary tumors of the spine (PTSs). These tumors have a low incidence and are pathologically heterogeneous, and treatment approaches are diverse. Appropriate evidence-based care is imperative. Failure to follow validated oncological principles may lead to unnecessary mortality and profound morbidity. This paper outlines a scientific model that provides significant evidence guiding the treatment of PTSs.
A four-stage approach was used: 1) planning: data from large-volume centers were reviewed to provide insight; 2) recruitment: centers were enrolled and provided the necessary infrastructure; 3) retrospective stage: existing medical records were reviewed and completed with survival data; and 4) prospective stage: prospective data collection has been implemented. The AOSpine Knowledge Forum Tumor designed six modules: demographic, clinical, diagnostic, therapeutic, local recurrence, survival, and perioperative morbidity data fields and provided funding.
It took 18 months to implement Stages 1–3, while Stage 4 is ongoing. A total of 1495 tumor cases were captured and diagnosed as one of 18 PTS histotypes. In addition, a PTS biobank network has been created to link clinical data with tumor pathology and molecular analysis.
This scientific model has not only aggregated a large amount of PTS data, but has also established an international collaborative network of spine oncology centers. Access to large volumes of data will generate further research to guide and enhance PTS clinical management. This model could be applied to other rare neoplastic conditions. Clinical trial registration no.: NCT01643174 (ClinicalTrials.gov).
Michael G. Fehlings, Justin S. Smith, Branko Kopjar, Paul M. Arnold, S. Tim Yoon, Alexander R. Vaccaro, Darrel S. Brodke, Michael E. Janssen, Jens R. Chapman, Rick C. Sasso, Eric J. Woodard, Robert J. Banco, Eric M. Massicotte, Mark B. Dekutoski, Ziya L. Gokaslan, Christopher M. Bono and Christopher I. Shaffrey
Rates of complications associated with the surgical treatment of cervical spondylotic myelopathy (CSM) are not clear. Appreciating these risks is important for patient counseling and quality improvement. The authors sought to assess the rates of and risk factors associated with perioperative and delayed complications associated with the surgical treatment of CSM.
Data from the AOSpine North America Cervical Spondylotic Myelopathy Study, a prospective, multicenter study, were analyzed. Outcomes data, including adverse events, were collected in a standardized manner and externally monitored. Rates of perioperative complications (within 30 days of surgery) and delayed complications (31 days to 2 years following surgery) were tabulated and stratified based on clinical factors.
The study enrolled 302 patients (mean age 57 years, range 29–86) years. Of 332 reported adverse events, 73 were classified as perioperative complications (25 major and 48 minor) in 47 patients (overall perioperative complication rate of 15.6%). The most common perioperative complications included minor cardiopulmonary events (3.0%), dysphagia (3.0%), and superficial wound infection (2.3%). Perioperative worsening of myelopathy was reported in 4 patients (1.3%). Based on 275 patients who completed 2 years of follow-up, there were 14 delayed complications (8 minor, 6 major) in 12 patients, for an overall delayed complication rate of 4.4%. Of patients treated with anterior-only (n = 176), posterior-only (n = 107), and combined anterior-posterior (n = 19) procedures, 11%, 19%, and 37%, respectively, had 1 or more perioperative complications. Compared with anterior-only approaches, posterior-only approaches had a higher rate of wound infection (0.6% vs 4.7%, p = 0.030). Dysphagia was more common with combined anterior-posterior procedures (21.1%) compared with anterior-only procedures (2.3%) or posterior-only procedures (0.9%) (p < 0.001). The incidence of C-5 radiculopathy was not associated with the surgical approach (p = 0.8). The occurrence of perioperative complications was associated with increased age (p = 0.006), combined anterior-posterior procedures (p = 0.016), increased operative time (p = 0.009), and increased operative blood loss (p = 0.005), but it was not associated with comorbidity score, body mass index, modified Japanese Orthopaedic Association score, smoking status, anterior-only versus posterior-only approach, or specific procedures. Multivariate analysis of factors associated with minor or major complications identified age (OR 1.029, 95% CI 1.002–1.057, p = 0.035) and operative time (OR 1.005, 95% CI 1.002–1.008, p = 0.001). Multivariate analysis of factors associated with major complications identified age (OR 1.054, 95% CI 1.015–1.094, p = 0.006) and combined anterior-posterior procedures (OR 5.297, 95% CI 1.626–17.256, p = 0.006).
For the surgical treatment of CSM, the vast majority of complications were treatable and without long-term impact. Multivariate factors associated with an increased risk of complications include greater age, increased operative time, and use of combined anterior-posterior procedures.
Ziya L. Gokaslan, Patricia L. Zadnik, Daniel M. Sciubba, Niccole Germscheid, C. Rory Goodwin, Jean-Paul Wolinsky, Chetan Bettegowda, Mari L. Groves, Alessandro Luzzati, Laurence D. Rhines, Charles G. Fisher, Peter Pal Varga, Mark B. Dekutoski, Michelle J. Clarke, Michael G. Fehlings, Nasir A. Quraishi, Dean Chou, Jeremy J. Reynolds, Richard P. Williams, Norio Kawahara and Stefano Boriani
A chordoma is an indolent primary spinal tumor that has devastating effects on the patient's life. These lesions are chemoresistant, resistant to conventional radiotherapy, and moderately sensitive to proton therapy; however, en bloc resection remains the preferred treatment for optimizing patient outcomes. While multiple small and largely retrospective studies have investigated the outcomes following en bloc resection of chordomas in the sacrum, there have been few large-scale studies on patients with chordomas of the mobile spine. The goal of this study was to review the outcomes of surgically treated patients with mobile spine chordomas at multiple international centers with respect to local recurrence and survival. This multiinstitutional retrospective study collected data between 1988 and 2012 about prognosis-predicting factors, including various clinical characteristics and surgical techniques for mobile spine chordoma. Tumors were classified according to the Enneking principles and analyzed in 2 treatment cohorts: Enneking-appropriate (EA) and Enneking-inappropriate (EI) cohorts. Patients were categorized as EA when the final pathological assessment of the margin matched the Enneking recommendation; otherwise, they were categorized as EI.
Descriptive statistics were used to summarize the data (Student t-test, chi-square, and Fisher exact tests). Recurrence and survival data were analyzed using Kaplan-Meier survival curves, log-rank tests, and multivariate Cox proportional hazard modeling.
A total of 166 patients (55 female and 111 male patients) with mobile spine chordoma were included. The median patient follow-up was 2.6 years (range 1 day to 22.5 years). Fifty-eight (41%) patients were EA and 84 (59%) patients were EI. The type of biopsy (p < 0.001), spinal location (p = 0.018), and if the patient received adjuvant therapy (p < 0.001) were significantly different between the 2 cohorts. Overall, 58 (35%) patients developed local recurrence and 57 (34%) patients died. Median survival was 7.0 years postoperative: 8.4 years postoperative for EA patients and 6.4 years postoperative for EI patients (p = 0.023). The multivariate analysis showed that the EI cohort was significantly associated with an increased risk of local recurrence in comparison with the EA cohort (HR 7.02; 95% CI 2.96–16.6; p < 0.001), although no significant difference in survival was observed.
EA resection plays a major role in decreasing the risk for local recurrence in patients with chordoma of the mobile spine.