Variation of C1 spinolaminar line and prevalence of C1 stenosis in normal population

Classification and Surgical Treatment of Developmental Spinal Canal Stenosis at Atlas Level: A 15-Case Study

STUDY DESIGN

A retrospective study.

OBJECTIVE

Investigate the diagnosis and surgery strategy for treatment of development spinal canal stenosis (DSSA) at atlas plane based on computerized tography (CT) image characters.

SUMMARY OF BACKGROUND DATA

The occurrence of spinal canal stenosis in the atlas plane is relatively rare compared with lower cervical.

METHODS

Fifteen patients diagnosed with DSSA were included from 2014 to 2018. They are divided into four subgroups based on the character of CT images: group I (small size atlas), group II (hypertrophy of posterior arch of the atlas [PAA]), group III (incurved of PAA), and group IV (hypertrophy odontoid).

RESULTS

There are type I 7, type II 3, type III 2, and group IV 3 in the 15 cases. All the patients received different surgery procedures respectively: (1) posterior arch osteotomy were performed for group I/III//IV without atlantoaxial dislocation, (2) posterior arch resect and replantation were performed for group II, (3) occipital cervical fixation and fusion were added to the patients with associated atlantoaxial dislocation (AAD), (4) a new method of odontoid reduce and atlantoaxial fixation by transoral approach were performed for group IV with associated AAD. All cases underwent surgery successfully which included posterior occipitocervical fixation (OCF) + posterior arch resection (PAR) eight cases, PAR four cases, posterior arch remodeling and re-implantation (PARR) two cases, and Dens remodeling + trans-oral anterior reduction and plate fixation (DR+TARP) one case without severe complications. All patients show different improvement in the symptoms. Japanese orthopaedic association score improved from 9.2 to 14.7 in 1 year follow-up.

CONCLUSION

DSSA could be easily diagnosed and divided into four subgroups according to the character of CT image, corresponding surgery strategy could receive a fine clinical result.Level of Evidence: 4.

Symptomatic Atlas Hypoplasia in a Latin-American Patient: Case Report and Literature Review

Background:

Atlas hypoplasia is an infrequent cause of upper cervical stenosis. Only 24 cases in nonsyndromic adult population have been published. We are not aware of previous reports describing isolated fully formed atlas hypoplasia in a Latin-American patient. The purpose of this work was to report a case of an 80-year-old Argentinian woman with cervical myelopathy because of atlas hypoplasia and a literature review about this subject.

Methods:

A clinical case and an extended review of the literature are presented. We assessed from each case: age, sex, posterior atlanto-dens interval, surgical treatment, outcomes, and follow-up period.

Results:

Neurologic symptoms markedly improved after posterior decompression from severe to moderate in the Japanese Orthopaedic Association Scoring System and from four to three on the Nurick scale. Twenty-five patients were analyzed (mean 58.4 years, 32% female). The mean posterior atlanto-dens interval was 8.8 mm. Twenty-three patients underwent decompression alone, and two needed posterior fusion. All patients reported clinical improvement at an average follow-up of 13 months.

Conclusion:

Cervical myelopathy caused by fully formed atlas hypoplasia is not an exclusive pathology of far east population, and it may present in nonsyndromic patients. Surgical treatment by C1 laminectomy improved neurologic impairment.

Study Design:

Case report and literature review.

A New Posterior Extensor Attachment-Point Reconstruction Technique for Cervical Spondylotic Myelopathy Involving C2 Segment: Clinical Outcome and Safety

BACKGROUND AND STUDY AIM

 Cervical spondylotic myelopathy (CSM) is a common degenerative disease that mainly occurs in elder patients, leading to different degrees of neurological dysfunction. Spinal cord involvement is mainly distributed at the C3-C7 segments, but it may also involve up to the C2 level. This study aimed to assess the clinical efficacy and safety of open-door laminoplasty using a new extensor attachment-point reconstruction technique for treating CSM involving the C2 segment.

PATIENTS AND METHODS

 Fifty-nine patients with CSM involving the C2 segment and undergoing open-door laminoplasty were included in this retrospective study. Based on the titanium plate used in the operation, patients were divided into two groups, a reconstructed titanium plate fixation (RPF) group (n = 28) and a conventional titanium plate fixation (CPF) group (n = 31). Improvements in neurological function, cervical range of motion (ROM), cervical curvature index (CCI), preservation of posterior cervical muscle mass, and axial symptoms were compared between the two groups.

RESULTS

 There were no significant differences in operative time and intraoperative blood loss between the groups (p > 0.05). The Japanese Orthopaedic Association (JOA) score significantly increased in both groups postsurgery (p < 0.05); the neurological recovery rate was similar between the two groups (64.1 ± 13.3% vs. 65.9 ± 14.7%, p > 0.05). There was no significant loss of cervical ROM in either group (p > 0.05). The anteroposterior dural sac diameter at the C2 level was significantly enlarged in both groups (p < 0.05). Alternatively, CCI was significantly reduced in the CRP group (p < 0.05) but unchanged in the RPF group (p > 0.05). The cross-sectional area of the posterior cervical muscles was also significantly reduced in the CPF group (p < 0.05) but maintained in the RPF group (p > 0.05). Finally, axial symptoms were more severe in the CPF group than in the RPF group (p < 0.05).

CONCLUSION

 Laminoplasty is an effective surgical procedure for CSM involving the C2 segment. The reconstructed titanium plate achieved superior maintenance of cervical curvature and reduced both muscle atrophy and severity of axial symptoms compared with titanium conventional plates.