Spinal Surgery 8 8 0 Original Article Successful Treatment of Proximal type Cervical Spondylotic Amyotrophy by Anterior Decompression, Miyuki Fukuda, M.D., Shiro Chitoku, M.D., Hiroyuki Yoneda, M.D., Iwao Nishiura, M.D., Shunichi Yoneda, M.D., Satoru Kawakami, M.D., Keisuke Yamada, M.D. Abstract Objective Proximal type cervical spondylotic amyotrophy CSA is a rare clinical condition characterized by focal disturbance of the C C6 ventral nerve roots and or the spinal segment of C 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 patients men, women with proximal type CSA who underwent anterior decompression at Nipponbashi hospital between 00 and 0. Clinical presentation, characteristics of images, particularly concerning kyphosis and high intensity area HIA on T 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.. The mean age of patients was 6. years range 76 years, and the mean symptom duration was.7 months. Twenty nine percent of the patients suffered from pure motor disturbance. Preoperative MMT grade was significantly lower in 9 69 years old patients. The preoperative MMT grades were.9 years old,. 9 69 years old, and.70 years old. There was no correlation between symptom duration and period until improvement. HIA was observed in eight cases 7. Among them, postoperative HIA resolved in two cases. The patients in the two cases were under 9 years old and HIA was not accompanied by kyphosis. In contrast, HIA remained in cases where the patients were over 9 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 C C6 corpectomy in cases with multisegmental HIA and disk hernia, C corpectomy in cases with C localized disk hernia and instability, C corpectomy in cases with C localized disk hernia, and C foraminotomy in cases with the C 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. Received August 0, 0 accepted June 6, 0 Key words cervical spondylotic amyotrophy, proximal type, C palsy, anterior decompression Address reprint requests to Miyuki Fukuda, M.D., Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kawahara cho, Shogoin, Sakyo ku, Kyoto shi, Kyoto 606 807, Japan 606 807 VOL. 8 NO. 0 8
a b Fig. The typical extent of corpectomy at C as represented by the images of case 6 Dotted line indicates the corpectomy area. a Anterior view of dimensional computed tomography D CT. Corpectomy should be performed at mm from the caudal edge of C spinal body for sufficient decompression of C nerve root circle. b Sagittal view of CT. Extent of corpectomy is widened in the deeper parts for adequate decompression of nerve root. W C 6 C 6 C8 C8 6,7 controversial C 8 C C 00 0,7 07. 6 motor neuron disease ADL 6. 76 X CT MRI X mm Cobb 0 kyphosis mm MRI T corpectomy Corpectomy mm 0 mm / Fig. * VOL. 8 NO. 0 8
Table List of the cases according to age Case 6 7 8 9 0 Age 9 6 6 68 68 7 7 7 76 76 Motor disorder Lt, C, C6 Rt, C Lt, C, C6 Lt, C 7 Lt, C Bil, C, C6 Rt, C, C6 Rt, C, C6 Lt, C C7 Bil, C Rt, C, Leg Lt, C,6 Lt, C Rt, C, C6 Sensory disorder Pain, Pain, Pain, Pain, Pain, Diagnosis He C He C He C 6 He C C 6 OPLL He C He C He C He C 6 DS C He C He C He C 6 He C 6 HIA C 6 disappear C disappear C C 6 C SEA C SEA C 6 C Canal stenosis C 6 C 6 C C 6 C instability C C 7 C instability C 6 C instability Kyphosis C 7 C 7 C C 7 C 6 C 8 C 7 C 6 C 6 Fixation level, material C, A Key hole foraminotomy C 6, I C A C 6, A, P C, A, P C, A C, A C 6, I C, A, P C, A, P C, A C 6, I C 6, I, P A Apaceram spacer, DS degenerative spondylolisthesis, He disk hernia, HIA hyper intensity area on T weighted image, I autogenous iliac bone, numbness, laminoplasty month after anterior fusion for canal stenosis, SEA snake eye appearance, P fusion with plate Table List of the cases according to age Case 6 7 8 9 0 Symptom duration 8 M M M 7 M M 60 M 6 M M M M M M M M Recovery period 0 days M. M 7 M days days days M. M days M M days M Pre operative MMT 0 Average... M month, MMT manual muscle testing, p 0.0 Post operative MMT Improvement of MMT Average... Occupation Stage carpenter Clerk Unknown High place worker Driver Builder Retired Unknown Director Director Retired Medical doctor Retired Lawyer HOYA Technosurgical ABC MMT MMT MMT Table VOL. 8 NO. 0 8
Preoperative image T WI a 6 07 MMT 9. 9 69. 69. 9 69 Kruskal Wallis test p 0.0.7 9 9 69.6 70 8. 9 7 0 6 6 kyphosis 07 Kyphosis 69 9 9 69 80 70 80 alignment Postoperative image T WI Fig. Case, pre and postoperative MRI a Preoperative MRI demonstrated a disk hernia and hyper intense area on T weighted imaging T WIarrow at C. b One month after operation, MRI presented a total removal of disk hernia and the disappearance of hyper intense area. 78 8 case case Fig. b MRI CT C case 9 case OPLLcase C 6 C C case C case 6 8 case 0 C C case C C case key hole foraminotomy MMT.7 MMT.. MMT 8 6 9 69 9 MMT 9. 9 69. 70. 9. 0. 9 69 0.9 70 9. Fig. 6 case 68 C 6 C 6 VOL. 8 NO. 0 8
a b c d e f Fig. Radiological images of Case 6 C root and ventral horn were slightly compressed and deformed by spur and disk hernia mainly on the right side arrow in preoperative MRI T WI a and CT b. Bilateral foraminotomy was completely performed on C as shown in the postoperative MRI d and CT e. The deformation improved after operation. Postoperative sagittal CT f showed sufficient removal of spinal bone when compared with preoperative CT c. C 6 MMT C MMT motor neuron disease CT MRI C C MMT dynamics controversial ALS motor neuron disease flexion myelopathy 8 myelomalacia gliosis 9 C C C 6 C 6 6 C C C key hole foraminotomy C 6 C C C6 C C C6 7 0 C6 7 8 C C VOL. 8 NO. 0 8
a b Fig. Anatomical characteristics of C nerve root Dotted lines a and arrows b demonstrate the directions of nerve roots. C nerve roots are shorter and lie almost horizontally when compared with C6, C7, and C8 nerve roots. Fig. b is reprinted from reference with the permission of the auther, Dr. Shinomiya K. Fig., C C MRI case 6 Fig. C T 9, 6 7 8 9 kyphosis 9 6 kyphosis Oshima 7 kyphosis alignment 6,7 7,8,9 6,7,0 C 8 kyphosis Table kyphosis flexion myelopathy kyphosis C Tauchi 7 VOL. 8 NO. 0 8
8 8 MMT Zhang 9 7 6 8 7 6 9 69 70 9 9 69 8 kyphosis 9 69 MMT COI Cervical spondylotic amyotrophy Crandall & Batzdorf 0 999 006 97 Keegan JJ The cause of dissociated motor loss in the upper extremity with cervical spondylosis. J Neurosurg 8 6, 96 Kameyama T, Ando T, Yanagi T, et al Cervical spondylotic amyotrophy. Magnetic resonance imaging demonstration of intrinsic cord pathology. Spine 8, 998, Dissociated motor loss Keegan 980 0 09 009 6 009 7Tauchi R, Imagama S, Inoh H, et al Risk factors for a poor outcome following surgical treatment of cervical spondylotic amyotrophy a multicenter study. Eur Spine J 6 6, 0 8 C 6 79 86 0 9Mehalic TF, Pezzuti RT, Applebaum BI Magnetic resonance imaging and cervical spondylotic myelopathy. Neurosurgery 6 7 6, 990 0 C 6 8 9 99 Shinomiya K, Okawa A, Nakao K, et al Morphology of C ventral nerve rootlets as part of dissociated motor loss of deltoid muscle. Spine 9 0 0, 99 VOL. 8 NO. 0 8
66 67 00 0 00 Wada E, Yonenobu K, Suzuki S, et al Can intramedullary signal change on magnetic resonance imaging predict surgical outocome in cervical spondylotic myelopathy? Spine 6, 999 Vedantam A, Rajshekhar V Does the type of T weighted hyperintensity influence surgical outcome in patients with cervical spondylotic myelopathy? A rewiew. Eur Spine J 96 06, 0 6Mastronardi L, Elsawaf A, Roperto R, et al Prognostic relevance of the postoperative evolusion of intramedullary spinal cord changes in signal intensity on magnetic resonance imaging after anterior decompression for cervical spondylotic myelopathy. J Neurosurg Spine 7 6 6, 007 7Oshima Y, Seichi A, Takeshita K, et al Natural course and prognostic factors in patients with mild cervical spondylotic myelopathy with increased signal intensity on T weighted magnetic resonance imaging. Spine 7 909 9, 0 8 8 009 9Zhang JT, Yang da L, Shen Y, et al Anterior decomression in the management of unilateral cervical spondylotic amyotrophy. Orthopedics 79 797, 0 0Takebayashi T, Yoshimoto M, Ida K, et al Minimum invasive posterior decompression for cervical spondylotic amyotrophy. J Orthop Sci 8 0 07, 0 flexion myelopathy 7 009 6 9 98 99 VOL. 8 NO. 0 8