Treatment of Reducible Atlantoaxial Dislocation and Basilar Invagination Using the Head Frame Reduction Technique and Atlantoaxial Arthrodesis

Study design: Retrospective case series. Object: To evaluate the outcomes of a head frame reduction and atlantoaxial arthrodesis technique for the treatment of reducible basilar invagination (BI) and atlantoaxial dislocation (AAD). Methods: Seventy-two reducible BI and AAD cases who were treated with the head frame reduction and atlantoaxial arthrodesis technique from June 2015 to December 2018 were retrospectively analyzed. Radiological measurements including the atlantodental interval (ADI), the height of odontoid process above Chamberlain line, Wackenheim line, clivus-canal angle (CCA) and JOA score were evaluated. Results: There was no death in this series. The follow-up period ranged from 6 to 32 months (mean: 21.2 months). Radiological, complete or 90% reduction was attained and complete decompression was demonstrated in all patients. The CCA increased from 123.22 ± 8.36 preoperatively to 143.05 ± 8.79 postoperatively (P < 0.01). There was no patient found postoperative dysphagia. Neurological improvement was observed in all patients, with the JOA scores increasing from 12.53 ± 1.93 preoperatively to 16.13 ± 1.23 postoperatively (P < 0.01). Solid bony fusion was demonstrated in 69 patients at follow-up (95.8%). Conclusion: Head frame reduction technique is a simple and effective treatment which could relief neurologic compression and adjust the CCA in patients with reducible AAD and BI with lower potential risks. Atlantoaxial fixation with short segmental fixation, strong purchase and low shearing force could maintain superior stabilization. The safety and long-term efficacy of such fixation and reduction technique were favorable, which illustrated that it could be a promising treatment algorithm for such kind of disease.

Comparison of Fusion Rates Based on Graft Material Following Occipitocervical and Atlantoaxial Arthrodesis in Adults and Children

BACKGROUND Fusion rates following rigid internal instrumentation for occipitocervical and atlantoaxial instability approach 100% in many reports. Based on this success and the morbidity that can be associated with obtaining autograft for fusion, surgeons increasingly select alternative graft materials. OBJECTIVE To examine fusion failure using various graft materials in a retrospective observational study. METHODS Insurance claims databases (Truven Health MarketScan® [Truven Health Analytics, Ann Arbor, Michigan] and IMS Health Lifelink/PHARMetrics [IMS Health, Danbury, Connecticut]) were used to identify patients with CPT codes 22590 and 22595. Patients were divided by age (≥18 yr = adult) and arthrodesis code, establishing 4 populations. Each population was further separated by graft code: group 1 = 20938 (structural autograft); group 2 = 20931 (structural allograft); group 3 = other graft code (nonstructural); group 4 = no graft code. Fusion failure was assigned when ≥1 predetermined codes presented in the record ≥90 d following the last surgical procedure. RESULTS Of 522 patients identified, 419 were adult and 103 were pediatric. Fusion failure occurred in 10.9% (57/522) of the population. There was no statistically significant difference in fusion failure based on graft material. Fusion failure occurred in 18.9% of pediatric occipitocervical fusions, but in 9.2% to 11.1% in the other groups. CONCLUSION Administrative data regarding patients who underwent instrumented occipitocervical or atlantoaxial arthrodesis do not demonstrate differences in fusion rates based on the graft material selected. When compared to many contemporary primary datasets, fusion failure was more frequent; however, several recent studies have shown higher failure rates than previously reported. This may be influenced by broad patient selection and fusion failure criteria that were selected in order to maximize the generalizability of the findings.

William Edward Gallie (1882–1959): father of the Gallie wiring technique for atlantoaxial arthrodesis

William Edward Gallie (1882–1959) was a Canadian general surgeon with special expertise in orthopedic surgery. His experience with surgical management of cervical spine subluxation led him to invent a method of cervical wiring of the atlas to the axis. His method of C1–2 wiring has since been modified, but it still remains one of the three most commonly taught wiring techniques in neurosurgical training programs. Gallie is also hailed for instituting the first surgical training program in Canada, a curriculum his pupils memorialized as the “Gallie course” in surgery. In this historical vignette, the authors describe Gallie’s life and depict his contributions to surgery.

Mineralization of the transverse ligament of the atlas causing compressive radiculopathy

Summary Objective: To describe a case of a Boxer dog with radiculopathy due to mineralization of the transverse ligament of the atlas and subsequent resorption and resolution of clinical signs after atlantoaxial arthrodesis and odontoidectomy. Case Report: A five-year-old neutered female Boxer dog was presented with a four-month history of cervical hyperaesthesia refractory to medical management. Neurological examination and magnetic resonance imaging indicated a diagnosis of radiculopathy due to cervical nerve root impingement by dystrophic mineralization of the transverse ligament of the atlas. Odontoidectomy was performed by a ventral approach and atlantoaxial arthrodesis was achieved with a ventral composite polymethylmethacrylate and pin fixation. Results: Atlantoaxial arthrodesis and progressive resorption of the mineralization following stabilization facilitated indirect decompression. The radioclinical diagnosis and response to arthrodesis was considered ana -logous to retro-odontoid pannus in the human. Clinical relevance: A clinical condition similar to retro-odontoid pannus may exist in the canine and may be amenable to atlantoaxial arthrodesis.

Ossification of the Posterior Atlantoaxial Membrane Associated with an Os Odontoideum: A Case Report

We report a case of ossification of the posterior atlantoaxial membrane associated with an os odontoideum in a 46-year-old woman. She developed myelopathy following a minor motor vehicle accident. The patient underwent posterior atlantoaxial arthrodesis and resection of the ossified lesion and recovered uneventfully. Long-standing atlantoaxial instability might have played a role in ectopic ossification of the posterior atlantoaxial membrane.