Efficacy and feasibility of one-stage posterior approach for Toyama Ⅲb and Ⅵ inner and outer dumbbell tumors in upper cervical spinal canal

English Keywords:Upper cervical spine  Dumbbell tumor  Toyama classification  Surgical treatment

English Abstract:

  【Abstract】 Objectives: To evaluate the feasibility and short-term clinical efficacy of one-stage posterior surgical resection for Toyama Ⅲb and Ⅵ upper cervical spinal canal inner and outer dumbbell tumors. Methods: From January 2006 to January 2016, 10 cases with Toyama Ⅲb and Ⅵ inner and outer upper cervical spinal canal dumbbell tumors undergoing resection of tumors and reconstruction of spinal stability by one-stage posterior approach were reviewed retrospectively. There were 8 males and 2 females, with a mean age of 56.2±7.8 years(range, 40-65 years). There were 8 with neurinoma and 2 with neurofibroma. Based on the tumor site, there were 5 cases in C1/2, 3 in C2/3, and 2 in C3/4. According to Toyama classification, there were 7 cases of Ⅲb and 3 cases of Ⅵ. Before operation, the maximum diameter from the tumor outside of spinal canal to dural margin measured in preoperative MRI image was 4.0-6.5cm(mean 4.8±0.7cm); the average JOA score was 9.5±3.5. Based on the ASIA classification, 1 case was in grade B, 1 in grade C, 2 in grade D and 6 in grade E. After operation, neurological function was evaluated by JOA score and ASIA grade. Besides, X-ray was reviewed to assess the stability of cervical spine. Results: All tumors were resected successfully by one-stage posterior approach, and the tumor outside of spinal canal was en bloc excision, without vertebral artery injury and deteriorative neurological function. The average operation time was 231.0±18.5min(range, 210-270min), the average intraoperative blood loss was 550.0±87.9ml(range, 400-700ml), and the average discharge time was 7.2±0.8 days(range, 6-8 days). All patients had a follow-up of 6-15 months(mean, 12.0±3.0 months), no tumor recurrence was noted, the neurological symptoms and positive signs of patients were significantly relieved after operation. At 6 months after operation, the mean JOA score of postoperation was 15.4±1.4, which showed statistically significant difference compared with that of preoperation(P<0.05). There were 1 case in grade D and 9 cases in grade E based on ASIA classification, the only one case in grade D also recovered to grade E at final follow-up, and there were significant differences between preoperation and final follow-up(P<0.05). Instrument failure or kyphosis was not detected in 10 patients. Conclusions: The Toyama Ⅲb and Ⅵ inner and outer upper cervical spinal canal dumbbell tumors can be surgically removed and the stability of cervical spine can be reconstructed by one-stage posterior approach, the short-term clinical efficacy is satisfactory.