Craniocervical junction zone malformations often have an insidious onset, a variety of clinical phenotypes, and are often combined with multiple malformations, making their systematic classification and staging more difficult.At present, craniocervical junction area malformations are often classified into congenital and acquired, and can also be classified into skull base malformations, atlantoaxial malformations, and cardinal malformations according to their locations. For patients with obvious occipitocervical or atlantoaxial instability, combined with symptoms of high cervical spinal cord damage, internal fixation and fusion surgery should be performed aggressively to avoid irreversible nerve damage.There is a lack of detailed categorisation and summary of the treatment of diseases associated with craniocervical junction malformations in the literature, and the treatment strategies for some of these malformations are still controversial, with different perceptions and treatment concepts in the national and international literature.

Craniocervical junction zone malformations often have an insidious onset, a variety of clinical phenotypes, and are often combined with multiple malformations, making their systematic classification and staging more difficult.At present, craniocervical junction area malformations are often classified into congenital and acquired, and can also be classified into skull base malformations, atlantoaxial malformations, and cardinal malformations according to their locations. For patients with obvious occipitocervical or atlantoaxial instability, combined with symptoms of high cervical spinal cord damage, internal fixation and fusion surgery should be performed aggressively to avoid irreversible nerve damage.There is a lack of detailed categorisation and summary of the treatment of diseases associated with craniocervical junction malformations in the literature, and the treatment strategies for some of these malformations are still controversial, with different perceptions and treatment concepts in the national and international literature.

The training of orthopedic residents in Taiwan, China includes post graduate year and specialist training, which contain continuous orthopedic specialist training, humanistic training, and holistic education to ensure the high post competency of orthopedic residents. The training process is oriented towards competency and outcome, emphasizing the cultivation of core competencies. Comprehensive quantitative standards have been established to comprehensively evaluate the post competency of residents through theoretical, technical, and clinical work assessments. In this paper, the literature on medical education and resident training in Taiwan was reviewed. The overall training system, assessment requirements, and humanistic training of orthopedic residents in Taiwan were introduced. In addition, the models of training orthopedic specialists were compared between Taiwan and Mainland of China represented by Peking University Medical Department to provide reference for the training program of orthopedic residents.

Objective:To evaluate the specialty of the clinical features, treatment procedure, clinical outcome, and prognosis in the patients with "sandwich" atlantoaxial dislocation (AAD).Methods:From 2008 to 2018, 160 cases with "sandwich" AAD were retrospectively selected from the case series of AAD in Peking University Third Hospital. The case series had 80 males and 80 females. The mean age at the initial visit was 35.5±14.6 years (range, 5-77). The clinical courses, treatment methodology and prognosis were reviewed. And the surgical approach, posterior fixation segment and the recovery of neurological function were mainly summarized. The atlantodental interval (ADI), the distance by which the odontoid exceeded the Chamberlain line and the cervical-medullary angle were analyzed.Results:The most common symptoms included weakness or numbness of the limbs (67.5%, 108/160), unstable gait (30%, 48/160) and vertigo (20%, 32/160). Among all, 130 cases (81.3%, 130/160) had myelopathy, with the Japanese Orthopaedic Association (JOA) scores from 4 to 16 (mean JOA scores 13.5±2.5). Cranial neuropathy was involved in 20 cases (12.5%). Radiological findings showed brainstem and/or cervical-medullar in 130 cases (81.3%), syringomyelia in 37 cases (23.1%) and Chiari malformation in 30 cases (18.8%). Computed tomography angiography (CTA) was performed in 90 cases, which showed vertebral artery anomalies in 55 cases (61.0%) and excessive medialized internal carotid artery in 5 cases (5.6%). All cases had no spinal cord or vertebral artery injury. The surgery included posterior occipito-cervical fusion (reducible dislocation, 145 cases), and transoral release followed by posterior fusion (irreducible dislocation, 15 cases). Fifty-seven cases were treated using alternative fixation technique. The average follow-up time was 50.5±22.4 months (range, 24 to 120 months). All of 152 cases (95.0%) achieved solid atlantoaxial fusion; there was no obvious osseous fusion formation on postoperative images in 6 cases (3.8%), but no atlantoaxial instability was found on dynamic radiographs; screw loosening happened in 2 patients (1.2%). Nine patients (5.6%) suffered complications, including 4 cases with recurrent dislocation, 2 screw loosening, 2 cases with bulbar paralysis and 1 wound infection. The mean postoperative JOA was 15.1±1.8 (range, 5-17), and the mean neurological improvement rate was 42.9%±33.3% in the patients with myelopathy.Conclusion:"Sandwich" AAD, a subgroup of AAD, has unique clinical features: earlier onset age and more severe myelopathy. The incidence of bone and vascular malformation is higher. So alternative surgical plan and hybrid fixation should be prepared for this subgroup of AAD.