This study aims to 1) determine reported cannabis use among patients waiting for thoracolumbar surgery and to 2) identify demographics and health differences between cannabis-users and non-cannabis users.

This observational cohort study is a retrospective national multicenter review data from the Canadian Spine Outcomes and Research Network registry. Patients were dichotomized as cannabis users and non-cannabis users. Variables of interest: age, sex, BMI, smoking status, education, work status, exercise, modified Oswestry Disability Index (mODI), the Numerical Rating Scales (NRS) for leg and back pain, tingling/numbness scale, SF-12 Quality of Life Questionnaire - Mental Health Component (MCS), use of prescription cannabis, recreational cannabis, and narcotic pain medication. Continuous variables were compared using an independent t-test and categorical variables were compared using chi-square analyses.

Cannabis-use was reported by 28.4% of pre-operative patients (N=704), 47% of whom used prescription cannabis. Cannabis-use was reported most often by patients in Alberta (43.55%), British Colombia (38.09%) and New Brunswick (33.73%). Patients who reported using cannabis were significantly younger (mean=52.9 versus mean=61.21,). There was a higher percentage of concurrent narcotic-use (51.54 %) and smoking (21.5%) reported in cannabis-users in comparison to non-cannabis users (41.09%,p=0.001; 9.51%, p=0.001, respectively). There were significant differences in cannabis-use based on pathology (p=0.01). Patients who report using cannabis had significantly worse MCS scores (difference=3.93, p=0.001), and PHQ-8 scores (difference=2.51, p=0.001). There was a significant difference in work status (p=0.002) with cannabis-users reporting higher rates (20%) of being employed, but not working compared to non-cannabis users (11.13%). Non-cannabis users were more likely to be retired (45.92%) compared to cannabis-users (31.31%). There were no significant differences based on cannabis use for sex, education, exercise, NRS-back, NRS-Leg, tingling-leg, mODI, or health state.

Thoracolumbar spine surgery patients are utilizing cannabis prior to surgery both through recreational use and prescription. Patients who are using cannabis pre-operatively did not differ in regards to reported pain or disability from non-users, though they did in demographic and mental health variables.

This study aims to 1) determine reported cannabis use among patients waiting for thoracolumbar surgery and to 2) identify demographics and health differences between cannabis-users and non-cannabis users.

This observational cohort study is a retrospective national multicenter review data from the Canadian Spine Outcomes and Research Network registry. Patients were dichotomized as cannabis users and non-cannabis users. Variables of interest: age, sex, BMI, smoking status, education, work status, exercise, modified Oswestry Disability Index (mODI), the Numerical Rating Scales (NRS) for leg and back pain, tingling/numbness scale, SF-12 Quality of Life Questionnaire - Mental Health Component (MCS), use of prescription cannabis, recreational cannabis, and narcotic pain medication. Continuous variables were compared using an independent t-test and categorical variables were compared using chi-square analyses.

Cannabis-use was reported by 28.4% of pre-operative patients (N=704), 47% of whom used prescription cannabis. Cannabis-use was reported most often by patients in Alberta (43.55%), British Colombia (38.09%) and New Brunswick (33.73%). Patients who reported using cannabis were significantly younger (mean=52.9 versus mean=61.21,). There was a higher percentage of concurrent narcotic-use (51.54 %) and smoking (21.5%) reported in cannabis-users in comparison to non-cannabis users (41.09%,p=0.001; 9.51%, p=0.001, respectively). There were significant differences in cannabis-use based on pathology (p=0.01). Patients who report using cannabis had significantly worse MCS scores (difference=3.93, p=0.001), and PHQ-8 scores (difference=2.51, p=0.001). There was a significant difference in work status (p=0.002) with cannabis-users reporting higher rates (20%) of being employed, but not working compared to non-cannabis users (11.13%). Non-cannabis users were more likely to be retired (45.92%) compared to cannabis-users (31.31%). There were no significant differences based on cannabis use for sex, education, exercise, NRS-back, NRS-Leg, tingling-leg, mODI, or health state.

Thoracolumbar spine surgery patients are utilizing cannabis prior to surgery both through recreational use and prescription. Patients who are using cannabis pre-operatively did not differ in regards to reported pain or disability from non-users, though they did in demographic and mental health variables.

Pain management in spine surgery can be challenging. Cannabis might be an interesting choice for analgesia while avoiding some side effects of opioids. Recent work has reported on the potential benefits of cannabinoids for multimodal pain control, but very few studies focus on spinal surgery patients. This study aims to examine demographic and health status differences between patients who report the use of (1) cannabis, (2) narcotics, (3) cannabis and narcotics or (4) no cannabis/narcotic use.

Retrospective cohort study of thoracolumbar patients enrolled in the CSORN registry after legalization of cannabis in Canada. Variables included: age, sex, modified Oswestry Disability Index (mODI), Numerical Rating Scales (NRS) for leg and back pain, tingling/numbness leg sensation, SF-12 Quality of Life- Mental Health Component (MCS), Patient Health Questionnaire (PHQ-9), and general health state. An ANCOVA with pathology as the covariate and post-hoc analysis was run.

The majority of the 704 patients enrolled (mean age: 59; female: 46.9%) were non-users (41.8%). More patients reported narcotic-use than cannabis-use (29.7% vs 12.9%) with 13.4% stating concurrent-use. MCS scores were significantly lower for patients with concurrent-use compared to no-use (mean of 39.95 vs 47.98, p=0.001) or cannabis-use (mean=45.66, p=0.043). The narcotic-use cohort had significantly worse MCS scores (mean=41.37, p=0.001) than no-use. Patients reporting no-use and cannabis-use (mean 41.39 vs 42.94) had significantly lower ODI scores than narcotic-use (mean=54.91, p=0.001) and concurrent-use (mean=50.80, p=0.001). Lower NRS-Leg pain was reported in cannabis-use (mean=5.72) compared to narcotic-use (mean=7.19) and concurrent-use (mean=7.03, p=0.001). No-use (mean=6.31) had significantly lower NRS-Leg pain than narcotic-use (p=0.011), and significantly lower NRS-back pain (mean=6.17) than narcotic-use (mean=7.16, p=0.001) and concurrent-use (mean=7.15, p=0.012). Cannabis-use reported significantly lower tingling/numbness leg scores (mean=4.85) than no-use (mean=6.14, p=0.022), narcotic-use (mean=6.67, p=0.001) and concurrent-use (mean=6.50, p=0.01). PHQ-9 scores were significantly lower for the no-use (mean=6.99) and cannabis-use (mean=8.10) than narcotic-use (mean=10.65) and concurrent-use (mean=11.93) cohorts. Narcotic-use reported a significantly lower rating of their overall health state (mean=50.03) than cannabis-use (mean=60.50, p=0.011) and no-use (mean=61.89, p=0.001).

Patients with pre-operative narcotic-use or concurrent use of narcotics and cannabis experienced higher levels of disability, pain and depressive symptoms and worse mental health functioning compared to patients with no cannabis/narcotic use and cannabis only use. To the best of our knowledge, this is the first and largest study to examine the use of cannabis amongst Canadian patients with spinal pathology. This observational study lays the groundwork to better understand the potential benefits of adding cannabinoids to control pain in patients waiting for spine surgery. This will allow to refine recommendations about cannabis use for these patients.

Purpose: Adjacent Segment Degeneration (ASD) can occur after spinal fusion, disc degeneration, spinal stenosis, deformity, spondylolisthesis and fracture. The incidence is unknown and its occurence difficult to predict. Further major surgery is required to correct the clinical problem that exists although not all cases of ASD are symptomatic. The primary purpose of this study was to identify the incidence of ASD after multilevel (> /= 3 level) thoracolumbar fusions for degenerative disorders at a minimum 5 year followup. Risk factors for ASD were to be determined.

Method: 405 spinal fusions of three levels or greater, performed between 1988 and 2001, minimum five year followup were assessed for ASD. Radiographic data was available from a prospective data bank. The radiological incidence of ASD was distinguished from those that were clinically significant as determined by Oswestry Disability Index, back and leg pain visual analog scales.

Results: The incidence of ASD after extended spinal fusions overall was 28%, based on radiological evaluation. There was an 18% incidence of clinically significant ASD. 10% of the entire group required surgery to address ASD. The incidence varied according to the location of the fusion, number of levels, age and pre-existing disc degeneration and/or deformity at the end vertebrae. Overall it was difficult to predict risk factors but trends were noted. Long fusion (> /= 3 levels) have a significantly high risk of ASD by five years after the index operation. Adjacent level degenerative disc disease and spinal stenosis were the most common type of ASD.

Conclusion: The incidence of ASD by five years post spine fusion of three or more levels is 28% in over 405 cases. 10% of these cases needed further surgery. ASD is a clinically significant entity that deserves further study to aid in its prevention.

The purpose of the study is to evaluate the outcome of two methods: Posterolateral fusion and instrumentation versus posterolateral fusion, instrumentation and interbody fusion using clinical and radiological criteria in demographically similar groups. This is a prospective cohort study of sixty-four patients randomized to two therapeutic strategies (Level II study).

Sixty-four patients were randomized to either instrumented posterolateral fusion (control) or combined instrumented posterolateral and interbody fusion (study) in one level degenerative disorders of the lumbar spine. Demographics of the groups were similar including age, gender and other variables. The demographics of the groups were similar for one level degenerative disorders—disc herniation, spondylolisthesis and spinal stenosis. The primary outcome was measured by the Oswestry Disability Index at two years. There was no statistically significant difference. Secondary outcomes (SF36, VAS, fusion rate, disc height maintenance, maintenance of deformity correction, adjacent segment degeneration) were statistically similar in both groups. In conclusion, no clinical advantage with interbody fusion versus posterolateral fusion alone.

Analysis of the correlation between the pedicle shape and the spinal canal anatomy in scoliotic anatomic specimens.

S. Parent1, H. Labelle, W. Skalli, J. de Guise,

13175 Côte Ste-Catherine, Montréal, Québec H3T 1C5.

The objective of the present study was to analyze the correlation between the pedicle shape and spinal canal anatomy in scoliotic specimens. Vertebral canal anatomy was evaluated in a series of thirty anatomic scoliotic specimens and compared to thirty normal specimens. Spinal canal enlargement inversely correlated with pedicle width modifications on the concavity of scoliotic curves. These findings suggest that changes in pedicle anatomy are secondary to local changes in spinal cord position.

Recent studies have demonstrated the close relationship between the spinal cord and the pedicle on the concavity of the scoliotic curve of patients with scoliotic deformities. The hypothesis of the present study is that changes in spinal canal shape are related to spinal cord position and resulting bone remodeling. This study evaluated the characteristic changes of spinal canal shape in anatomic scoliotic specimens.

Posterior elements morphology is closely related to the local spinal cord anatomy and its relationship with the bony architecture.

The characteristic posterior element changes seen in scoliosis are likely the result of local bone remodeling.

Spinal asymmetry was observed in scoliotic specimens when compared to normal specimens. Spinal canal was enlarged asymmetrically on the concavity of thoracic scoliotic curves (p < 0.01). Overall, canal surface was greater in scoliotic specimens when compared to normal specimens (p < 0.01). These changes were more important at the apex of the curve.

Spinal canal characteristic shape was evaluated in thirty scoliotic anatomic specimens and thirty normal anatomic specimens using twelve parameters representing measures of right and left hemi-canal length, width or surface area. The 3-D coordinates of eight points taken at the periphery of each spinal canal were recorded.

The results of this study support the hypothesis that spinal canal shape is modified by the spinal cord position and that posterior element changes seen in scoliosis are in part due to bone remodeling in response to local neural anatomy modifications.

Funding: Fonds de Recherche en Santé du Québec

Preliminary results suggest that a new rhBMP-2 formulation may provide an alternative for autologous bone graft in two-level posterolateral fusions

The purpose of this study was to compare the success of instrumented two level fusions using a new rhBMP-2 formulation versus iliac crest bone graft (ICBG). In this formulation, rhBMP-2 was at a concentration of 2mg/cc in a Biphasic Calcium Phosphate (60% hydroxyapatite/40% tricalcium phosphate) ceramic granule carrier. Twenty-nine patients were enrolled in this multicentered, prospective, randomized study. Either 30cc of rhBMP-2/BCP or fresh ICBG were used. Clinical evaluations were done preoperatively, at discharge and 1.5, three, six, twelve and twenty-four months including Oswestry Disability Index SF36, back pain and leg pain questionnaires. CT scan and xrays were independently assessed at six, twelve, and twenty-four months. Fusion criteria included bilateral bridging trabecular bone on each level, less than 3mm translation, less than five degrees angulation . Seventeen patients received ICBG and twelve received rhBMP-2/BCP. With the use of rhBMP-2 average OR time was reduced from 3.8 to 2.9 hours. Twenty-nine patients (100%) have reached twenty-four month followup. Clinical improvements were similar in both groups, however, fusion success was much improved with the use of rhBMP-2. At twenty-four months all patients receiving rhBMP-2/BCP were fused versus 58% of ICBG patients. These results suggest that rhBMP-2/BCP may have improved fusion success in challenging two level posterolateral fusions as compared to ICBG.