Long-term outcomes of intrathecal baclofen in ambulatory multiple sclerosis patients: A single-center experience.

BACKGROUND: Intrathecal baclofen (ITB) is traditionally reserved for non-ambulatory patients. OBJECTIVE: To investigate outcomes of ITB in ambulatory multiple sclerosis (MS) patients. METHODS: Changes in outcome measures were estimated by a mixed effect model, while the complication rate was calculated using a logistic regression. Predictors of non-ambulatory status were identified by Cox model. RESULTS: In all, 256 patients received an ITB test injection and 170 underwent ITB surgery. Aggregate Modified Ashworth Scale (MAS) scores for the ambulatory ITB cohort decreased from 13.5 ± 6.96 to 4.54 ± 4.18 at 5 years (p < 0.001). There was no significant change in walking speed 1 year post ITB surgery (0.45 m/second ± 0.30 vs 0.38 m/second ± 0.39, p = 0.80) with 77.8% of patients remaining ambulatory which decreased to 41.7% at year 5. Longer MS disease duration (hazard ratio (HR): 1.04; 95% confidence interval (CI): 1.01-1.07; p = 0.018) and lower hip flexor strength (HR: 0.40; 95% CI: 0.27-0.57; p < 0.001) predicted non-ambulatory status after surgery. Complications were more likely in the ambulatory cohort (odds ratio (OR): 3.30, 95% CI: 2.17-5.02; p = 0.017). CONCLUSION: ITB is effective for ambulatory MS patients without compromising short-term walking speed, although a higher complication rate was observed in this cohort.

A quantitative analysis of posterolateral approaches to the ventral thoracic spinal canal.

BACKGROUND CONTEXT: Various posterolateral approaches exist to access ventral thoracic spinal canal pathologies. Selecting the optimal surgical approach requires sound understanding of the exposure and working angle afforded by each approach. PURPOSE: The purpose of this study was to quantify exposure of the ventral spinal canal with various posterolateral thoracic spinal approaches and to determine how regional anatomical differences affect measurements. STUDY DESIGN: This is a quantitative anatomical cadaveric study. METHODS: Four fresh cadaveric C7-L1 specimens were used with a saline infusion model to mimic in vivo thecal sac dimensions. Using stereotactic navigation, we measured exposure (expressed as percentage of total width) and maximum approach angle of the ventral spinal canal without thecal sac retraction after each surgical condition: laminectomy (L), 50% medial facetectomy (MF), transpedicular (TP), costotransversectomy (CTV), and lateral extracavitary (LE). The thoracic spine was divided into four regions (T1-T2, T3-T6, T7-T10, and T9-T12). A two-sided paired t test was used. RESULTS: At T1-T2, visualized exposures were 25.8%, 31.5%, 42.3%, 45.1%, and 46.8%, respectively, after each surgical condition. Costotransversectomy and LE did not provide significant increase in exposure compared with the preceding condition. At T3-T6, exposures were 19.1%, 29.6%, 38.7%, 44.4%, and 44.5%, respectively. Only LE did not provide significant increase in exposure compared with the preceding condition. At T7-T10, visualized exposures were 17.9%, 30.6%, 39.9%, 44.9%, and 53.3%, respectively. All successive surgical conditions provided a significant increase in exposure. At T11-T12, visualized exposures were 14.2%, 25.8%, 43.1%, 47.7%, and 52.7%, respectively. Only LE did not provide a significant increase in exposure compared with the preceding condition. Each successive surgical condition provided a significantly increased lateral approach angle compared with the preceding condition, except LE at T1-T2. Maximum approach angle was more favorable at T1-T2 for L, MF, TP, and CTV compared with other thoracic regions. CONCLUSIONS: Medial facetectomy and TP approaches provide significantly increased exposure of the ventral spinal canal at all thoracic regions. Costotransversectomy provided significantly increased exposure compared with TP at T3-T12. Lateral extracavitary only provided significantly increased exposure compared with CTV at T7-T10. The results of this study can be used preoperatively to determine the optimal approach based on quantitative measurements and region-specific anatomical differences.