Therapeutic effect of spinal cord stimulation on chronic disorders of consciousness after brain injury: A report of 110 cases

Objective To investigate the efficacy and influencing factors of spinal cord stimulation (SCS) in the treatment of patients with chronic disorders of consciousness (DOC) after brain injury. Methods The clinical data of 110 patients with chronic DOC after brain injury were analyzed retrospectively who were admitted to Department of Neurosurgery, the Seventh Medical Center of Chinese PLA General Hospital from August 2011 to December 2017. CT scan of the cervical spine was performed to show the location of the electrode implanted. All patients underwent clinical follow-up at 3 and 6 months after surgery. The follow-up included neurological physical examination and assessment based on modified coma recovery scale-revised (CRS-R). According to the patient's clinical symptom outcome and CRS-R scores, the surgical outcomes were evaluated and divided into effective and ineffective. Univariate and multivariate logistic regression analysis were used to explore risk factors affecting the patient′s outcomes. Results Cervical CT was performed after operation. The electrodes of 110 patients were implanted at cervical spinal epidural C2-C4 level. Stimulation parameters in 110 patients included the frequency of 5 Hz or 70 Hz, pulse width of 210 μs, voltage of 1-5 V, daily device-on time of 8-12 h, stimulation mode of 15-min stimulation with 15-min interval. At 6 months post surgery in this series of 110 patients, 38 cases were effective (good in 24 and improved in 14), 72 were ineffective (ineffective in 67 and death in 5), and the overall effective rate was 34.5% (38/110). Univariate analysis showed that age, duration of disease, CRS-R score, and preoperative surgical recommendation criterion were clinical factors affecting the patient′s outcome (all P < 0.05). Further multivariate logistic regression analysis showed that preoperative evaluation recommendation criterion was an independent risk factor affecting the patient′s outcome (OR=8.179, 95% CI: 2.171-30.816, P=0.002). CRS high score was an independent protective factor affecting the patient’s outcome (OR=0.304, 95% CI: 0.095-0.978, P=0.046). Conclusion SCS is effective in the treatment of DOC and can be used as one of the feasible treatments for DOC. The preoperative evaluation recommendation criterion is an independent risk factor for the efficacy of patients with DOC. Key words: Consciousness disorders; Treatment outcome; Factor analysis, statistical; Spinal cord stimulation