Objective Our previous study categorized atlanto-occipital joint (AOJ) morphology into 3 types, with types II and III-AOJ associated with Chiari malformation (CM) with and without type II basilar invagination (II-BI), respectively. This study aimed to assess the feasibility of tailoring surgical strategies for patients with CM based on AOJ morphological types.
Methods We retrospectively studied 212 CM patients who underwent foramen magnum decompression (FMD) or combined occipitocervical fusion (OCF). Patients were divided into 4 groups: (1) pure CM with II-AOJ who underwent FMD (CM-II-FMD); (2) pure CM with III-AOJ who underwent FMD+OCF (CM-III-OCF); (3) CM-III-FMD; and (4) CM+ II-BI with III-AOJ who underwent FMD+OCF (BI-III-OCF). Clinical data, including manifestations, imaging findings, surgical details, and neurological assessments, were analyzed at the final follow-up to assess surgical efficacy.
Results Patients in the BI-III-OCF, CM-III-OCF, and CM-II-FMD groups exhibited a significant improvement in clinical symptoms (pain, sensory disturbances, motor weakness, gait ataxia, and bladder and bowel dysfunction) compared to preoperative levels (p<0.05). Results from the Japanese Orthopaedic Association scale and Neck Disability Index indicated a significant reduction in the degree of neurological impairment within these groups (p<0.05). Furthermore, the Chicago Chiari Outcome Scale scores indicated superior surgical outcomes for patients in these groups. Imaging analyses demonstrated significant reductions in the syringomyelic segment, syringomyelia width, and tonsillar herniation distance among these patients (p<0.05). However, the CM-III-FMD group did not significantly improve in these areas (p>0.05). Postoperative complications occurred in 4.3% of FMD+OCF patients and 3.3% of FMD-only patients.
Conclusion AOJ morphological types can guide surgical treatment strategies for CM with or without II-BI. FMD alone is suitable for II-AOJ cases, whereas III-AOJ cases should be treated with FMD combined with OCF.
Objective The purpose of this study is to find the clinical and radiographic characteristics of traumatic craniocervical junction (CCJ) injuries requiring occipitocervical fusion (OC fusion) for early diagnosis and surgical intervention.
Methods We retrospectively reviewed 12 patients with CCJ injuries presenting to St. Michaels Hospital in Toronto who underwent OC fusion and looked into the following variables; (1) initial trauma data on emergency room arrival, (2) associated injuries, (3) imaging characteristics of computed tomography (CT) scan and magnetic resonance imaging (MRI), (4) surgical procedures, surgical complications, and neurological outcome.
Results All patients were treated as acute spinal injuries and underwent OC fusion on an emergency basis. Patients consisted of 10 males and 2 females with an average age of 47 years (range, 18–82 years). All patients sustained high-energy injuries. Three patients out of 6 patients with normal BAI (basion-axial interval) and BDI (basion-dens interval) values showed visible CCJ injuries on CT scans. However, the remaining 3 patients had no clear evidence of occipitoatlantal instability on CT scans. MRI clearly described several findings indicating occipitoatlantal instability. The 8 patients with normal values of ADI (atlantodens interval interval) demonstrated atlantoaxial instability on CT scan, however, all MRI more clearly and reliably demonstrated C1/2 facet injury and/or cruciate ligament injury.
Conclusion We advocate measures to help recognize CCJ injury at an early stage in the present study. Occipitoatlantal instability needs to be carefully investigated on MRI in addition to CT scan with special attention to facet joint and ligament integrity.
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Dyspnea or dysphagia after occipitocervical fusion is well-known complications. It could be occurred when occipitocervical fusion is performed with the neck flexion position which leads to the narrowing of the airway and retropharyngeal space. However, we experienced a case of dyspnea and dysphagia after posterior C1-C2 fusion. A 68-year-old male showed no evidence of occipitocervical instability in preoperative studies. He complained of progressive dyspnea and dysphagia after C1-2 fusion and follow-up computed tomography (CT) and magnetic resonance (MRI) showed relatively narrow spinal canal at the level of C1-2 compared to preoperative studies and serial plain radiographic studies decreased occipitocervical (O-C2) angle gradually. Despite of conservative treatment, his symptom was not improved. So we did C1 posterior arch decompression and extended fusion to the occiput with neck extension position. Dyspnea and dysphagia gradually improved after the surgery and complete recovery was observed within a month.
Though we did not know the causes of dyspnea and dysphagia exactly, two mechanisms were possible one was cord irritation due to anterior migration of C1 posterior arch after C1-2 fusion. The other was alar ligament disruption with microinstability between the occiput and atlas.
We present the case of dyspnea and dysphagia after posterior C1-2 fusion.
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