✓In this report, the authors describe a unique case of intermittent high cervical cord compression caused by a prolapsing neurofibroma at the C1–2 level. This 21-year-old man with known neurofibromatosis Type 1 presented with a mass between the anterior arch of the atlas and the odontoid peg, causing atlantoaxial dissociation and cord compression. The cervicomedullary compression appeared to be caused in part by the neurofibroma but also by the abnormal alignment and thickening of the ligaments between the clivus and C-2. Preoperative imaging repeated on the morning of surgery revealed that the atlantoaxial dissociation had reduced with relief of cord compression and the lesion prolapsed inferiorly. The authors discuss this unusual lesion and describe the associated operative findings and surgical management.
Michael O. Kelleher, Nasir A. Quarishi, Gamaliel Tan, Abhijit Guha and Eric M. Massicotte
Use of osteogenic protein-1 in patients at high risk for spinal pseudarthrosis: a prospective cohort study assessing safety, health-related quality of life, and radiographic fusion
Invited submission from the Joint Section on Disorders of the Spine and Peripheral Nerves, March 2007
Julio C. Furlan, Richard G. Perrin, Preneshlin V. Govender, Yuriy Petrenko, Eric M. Massicotte, Yoga R. Rampersaud, Stephen Lewis and Michael G. Fehlings
The capability of osteogenic protein (OP)–1 to induce bone formation has led to an increasing interest in its use in fusion surgery. This prospective study examines the safety and efficacy of OP-1 use in patients considered to be at a high risk for developing pseudarthrosis following reconstructive spinal surgery.
Outcome measures included documentation of adverse events, radiographic evaluation of fusion by an independent musculoskeletal radiologist blinded to treatment, the Oswestry Disability Index (ODI), and the 36-Item Short Form Health Survey (SF-36). The health-related quality of life (HRQOL) assessments (ODI and SF-36) were given at baseline and at 3, 6, 12, 18, and 24 months after the surgical OP-1 implant.
The study consisted of 17 male and 13 female patients, with a mean age of 53 years (range 20–77 years). Fourteen patients underwent operations for cervical disease, and 16 for lumbar disease, with a median postoperative follow-up of 24 months (range 13–46 months). There were significant improvements in the physical health (from 28.7 ± 1.5 to 34.2 ± 3; p = 0.025) and mental health (from 43.7 ± 2 to 47.5 ± 3.1; p = 0.015) summary scores on the SF-36. The mean postoperative ODI score at 6, 9, 12, and 18 months was significantly lower than the baseline ODI score, after taking into consideration a 10-point measurement error (p = 0.0003, p = 0.003, p = 0.004, and p = 0.032, respectively). At 24 months, however, the differences in ODI scores were no longer significant. Of the 30 patients, 24 (80%) were deemed to have a solid fusion. There were no allergic reactions to OP-1 and no symptomatic postoperative hematomas.
Our results suggest that the use of OP-1 is safe and may contribute to high fusion rates, as demonstrated by radiographs, reduced levels of disability, and improved HRQOL in patients considered to be at a high risk for developing a nonunion after spinal reconstructive surgery.
Shian Liu, Renaud Lafage, Justin S. Smith, Themistocles S. Protopsaltis, Virginie C. Lafage, Vincent Challier, Christopher I. Shaffrey, Kris Radcliff, Paul M. Arnold, Jens R. Chapman, Frank J. Schwab, Eric M. Massicotte, S. Tim Yoon, Michael G. Fehlings and Christopher P. Ames
Cervical stenosis is a defining feature of cervical spondylotic myelopathy (CSM). Matsunaga et al. proposed that elements of stenosis are both static and dynamic, where the dynamic elements magnify the canal deformation of the static state. For the current study, the authors hypothesized that dynamic changes may be associated with myelopathy severity and neck disability. This goal of this study was to present novel methods of dynamic motion analysis in CSM.
A post hoc analysis was performed of a prospective, multicenter database of patients with CSM from the AOSpine North American study. One hundred ten patients (34%) met inclusion criteria, which were symptomatic CSM, age over 18 years, baseline flexion/extension radiographs, and health-related quality of life (HRQOL) questionnaires (modified Japanese Orthopaedic Association [mJOA] score, Neck Disability Index [NDI], the 36-Item Short Form Health Survey Physical Component Score [SF-36 PCS], and Nurick grade). The mean age was 56.9 ± 12 years, and 42% of patients were women (n = 46). Correlations with HRQOL measures were analyzed for regional (cervical lordosis and cervical sagittal vertical axis) and focal parameters (kyphosis and spondylolisthesis between adjacent vertebrae) in flexion and extension. Baseline dynamic parameters (flexion/extension cone relative to a fixed C-7, center of rotation [COR], and range of motion arc relative to the COR) were also analyzed for correlations with HRQOL measures.
At baseline, the mean HRQOL measures demonstrated disability and the mean radiographic parameters demonstrated sagittal malalignment. Among regional parameters, there was a significant correlation between decreased neck flexion (increased C2–7 angle in flexion) and worse Nurick grade (R = 0.189, p = 0.048), with no significant correlations in extension. Focal parameters, including increased C-7 sagittal translation overT-1 (slip), were significantly correlated with greater myelopathy severity (mJOA score, Flexion R = −0.377, p = 0.003; mJOA score, Extension R = −0.261, p = 0.027). Sagittal slip at C-2 and C-4 also correlated with worse HRQOL measures. Reduced flexion/extension motion cones, a more posterior COR, and smaller range of motion correlated with worse general health SF-36 PCS and Nurick grade.
Dynamic motion analysis may play an important role in understanding CSM. Focal parameters demonstrated a significant correlation with worse HRQOL measures, especially increased C-7 sagittal slip in flexion and extension. Novel methods of motion analysis demonstrating reduced motion cones correlated with worse myelopathy grades. More posterior COR and smaller range of motion were both correlated with worse general health scores (SF-36 PCS and Nurick grade). To our knowledge, this is the first study to demonstrate correlation of dynamic motion and listhesis with disability and myelopathy in CSM.
Gabriel Y. F. Lee, Guillermo Paradiso, Charles H. Tator, Fred Gentili, Eric M. Massicotte and Michael G. Fehlings
The adult presentation of tethered cord syndrome (TCS) is well recognized but continues to pose significant diagnostic and management challenges. The authors performed a retrospective study of clinical outcomes after neurosurgical intervention in 60 adults with TCS.
All patients who underwent detethering surgery for caudal cord tethering at Toronto Western Hospital between August 1993 and 2004 were identified. Their clinical charts, operative records, and follow-up data were reviewed. Detethering procedures were performed in 62 patients (age range 17–72 years) for TCS of various origins. Long-term (mean 41.5 months) follow-up data were obtained in 60 patients. The tethering lesions were tight terminal filum in 29 patients, postrepair myelomeningocele in 15, lipomyelomeningocele/lipoma in nine, split cord malformation in four, and arachnoidal adhesions in three. Fifty-nine patients presented with progressive pain and/or neurological dysfunction. One patient underwent prophylactic sectioning of the terminal filum. Most patients (71%) had bladder dysfunction at presentation. Microsurgical release of the tethered cord was performed in each case while using multimodality intraoperative neurophysiological monitoring. The most common complication was cerebrospinal fluid leakage, which occurred in nine patients and was managed by reinforcement sutures in four patients, temporary external drainage in three, and the placement of a lumboperitoneal shunt in two. Infective complications included superficial wound infection in three patients, meningitis in one, and urinary tract infection in one. One patient who had undergone multiple previous intradural procedures experienced worsened foot weakness postoperatively. Another patient experienced temporary unilateral lower-limb numbness. At follow up, improvement was noted in the majority of patients presenting with back (78%) and leg (83%) pain. Improvement was more likely in patients with preoperative motor weakness than in those with sensory deficits. Overall, neurological status was improved or stabilized in 90% of patients. Subjective improvement in bladder function was noted in 50% of patients with bladder dysfunction at presentation.
Surgery in adult patients with TCS is safe and effective for improving pain and neurological status in the majority of patients; however, patients who have undergone previous intradural detethering procedures in general fare less well, and considerable judgment is required in their management.
Julio C. Furlan, Sukhvinder Kalsi-Ryan, Ahilan Kailaya-Vasan, Eric M. Massicotte and Michael G. Fehlings
Cervical spondylotic myelopathy (CSM) is the most common cause of spinal dysfunction in the elderly. Operative management is beneficial for most patients with moderate/severe myelopathy. This study examines the potential confounding effects of age, sex, duration of symptoms, and comorbidities on the functional outcomes and postoperative complications in patients who underwent cervical decompressive surgery.
We included consecutive patients who underwent surgery from December 2005 to October 2007. Functional outcomes were assessed using the Nurick grading system and the modified Japanese Orthopaedic Association and Berg Balance scales. Comorbidity indices included the Charlson Comorbidity Index and the number of ICD-9 codes.
There were 57 men and 24 women with a mean age of 57 years (range 32–88 years). The mean duration of symptoms was 25.2 months (range 1–120 months). There was a significant functional recovery from baseline to 6 months after surgery (p < 0.01). Postoperative complications occurred in 18.5% of cases. Although the occurrence of complications was not significantly associated with sex (p = 0.188), number of ICD-9 codes (p = 0.113), duration of symptoms (p = 0.309), surgical approach (p = 0.248), or number of spine levels treated (p = 0.454), logistic regression analysis showed that patients who developed complications were significantly older than patients who had no complications (p = 0.018). Only older age (p < 0.002) and greater number of ICD-9 codes (p < 0.01) were significantly associated with poorer functional recovery after surgical treatment. However, none of the studied factors were significantly associated with clinically relevant functional recovery after surgical treatment for CSM (p > 0.05).
Our results indicate that surgery for CSM is associated with significant functional recovery, which appears to reach a plateau at 6 months after surgery. Age is a potential predictor of complications after decompressive surgery for CSM. Whereas older patients with a greater number of preexisting medical comorbidities had less favorable functional outcomes after surgery for CSM in the multivariate regression analysis, none of the studied factors were associated with clinically relevant functional recovery after surgery in the logistic regression analysis. Therefore, age-matched protocols based on preexisting medical comorbidities may reduce the risk for postoperative complications and improve functional outcomes after surgical treatment for CSM.
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.