近位型頚椎症性筋萎縮症14例に対しての前方手術成績

抄録

  Objective : Proximal-type cervical spondylotic amyotrophy (CSA) is a rare clinical condition characterized by focal disturbance of the C5-C6 ventral nerve roots and/or the spinal segment of C5-C6, especially at the site of the ventral horn. The purpose of this study was to investigate the effects of anterior decompression surgery on proximal-type CSA.

  Materials and Methods : We retrospectively analyzed the course of 14 patients (11 men, 3 women) with proximal-type CSA who underwent anterior decompression at Nipponbashi hospital between 2003 and 2011. Clinical presentation, characteristics of images, particularly concerning kyphosis and high-intensity area (HIA) on T2-weighted magnetic resonance images (MRI), surgical procedures, and improvement in manual muscle test (MMT) grade were reviewed. We also analyzed age-specific findings and the correlation between symptom duration and outcome.

  Results : The proportion of CSA in all cases of surgically treated cervical spondylosis was 3.4%. The mean age of patients was 63.1 years (range 43-76 years), and the mean symptom duration was 14.7 months. Twenty-nine percent of the patients suffered from pure motor disturbance. Preoperative MMT grade was significantly lower in 59-69 years old patients. The preoperative MMT grades were 3.5 (<59 years old), 1.4 (59-69 years old), and 3.4 (>70 years old). There was no correlation between symptom duration and period until improvement. HIA was observed in eight cases (57%). Among them, postoperative HIA resolved in two cases. The patients in the two cases were under 59 years old and HIA was not accompanied by kyphosis. In contrast, HIA remained in cases where the patients were over 59 years old and HIA was accompanied by kyphosis. The surgical outcome was satisfactory in all cases, including those with long symptom duration. Surgical procedures were C4-C6 corpectomy in cases with multisegmental HIA and disk hernia, C4/5 corpectomy in cases with C4/5 localized disk hernia and instability, C3/4 corpectomy in cases with C3/4 localized disk hernia, and C4/5 foraminotomy in cases with the C5 ventral root disturbance.

  Conclusion : It should be noted that same patients have no subjective symptoms despite muscle atrophy. Anterior decompression resulted in a good surgical outcome in all cases of proximal-type CSA. Since a certain amount of decompression of the ventral nerve roots and ventral horns is expected in an anterior approach, we recommend anterior decompression in proximal-type CSA.