Pedicle morphometry analysis of main thoracic apex adolescent idiopathic scoliosis.

INTRODUCTION: Screw insertion during scoliosis surgery uses free-hand pedicle screw insertion methods. However, there is a wide variation in pedicle shapes, sizes, and morphometry, especially in scoliosis patients. CT scan pedicle measurements in main thoracic Lenke type 1 adolescent idiopathic scoliosis can help visualize this diversity. This study aimed to highlight the features of pedicle morphometry on the concave and convex sides, including pedicle diameter (width in axial and height in the sagittal plane), the depth to the anterior cortex, and Watanabe Pedicle classification in patients with main thoracic apex adolescent idiopathic scoliosis. MATERIALS AND METHODS: This study was a cross-sectional observational study of Adolescent Idiopathic Scoliosis (AIS) patients whose apex in the main thoracic patient underwent deformity correction procedures. We used a three-dimensional CT scan to evaluate pedicle morphometry on the apex vertebrae, three consecutive vertebrae above and below the apex. RESULTS: A total of 6 patients with apex main thoracic AIS with 84 pedicles consisting of 42 pedicles from each concave and convex curve were analyzed. All of the samples were female, with the mean age at the procedure being 21.2 ± 5.56. The mean cobb angle was 62° ± 23°, with the main apex between VT8-VT10. The size of the pedicle was bigger from upper to lower vertebrae. The mean pedicle depth, pedicle width, and pedicle height for the concave side were 36.06 ± 4.31 mm, 3.91 ± 0.66 mm, and 9.16 ± 1.52 mm, respectively. Meanwhile, the convex side is 37.52 ± 1.84 mm, 5.20 ± 0.55 mm, and 11.05 ± 0.70 mm, respectively. We found a significant difference between the concave and convex sides for the pedicle width and height. The concave and convex sides were mainly classified as type C (38%) and type A (50%) Watanabe pedicle. CONCLUSION: Pedicle width and pedicle height are significantly different between the concave and the convex side with convex side has better Watanabe pedicle classification. Pre-operative CT evaluation is essential for planning proper pedicle screw placement in AIS patients.

Occipitocervical fixation: A case report of our techniques and results.

INTRODUCTION: Occipitocervical fixation (OCF) can provide good fusion rate to treat various craniovertebral junction (CVJ) pathologies. Biomechanically it gives rigid fixation, good fusion rate, and allows for effective decompression. However, rigid fixation on the mobile occipitocervical junction has shortcomings that affect the post-operative clinical functional outcomes and range of motion. This study aimed to evaluate and elaborate the functional outcomes, range of motions, and radiographic findings in our patients underwent OCF. CASE REPORT: We presented a report of 3 patients underwent posterior decompression procedure followed by occipitocervical fixation. All three patients' clinical outcome was assessed clinically by, Japanese Orthopaedic Association (JOA) score and grading, Karnofsky, range of motion and radiographic cervical alignment evaluation parameters. RESULT: All patients have seen improvement (minimal 1 grade in JOA and >30 points of Karnofsky score) in 3 months after the procedure, had a tolerable range of motion limitation, normal range of cervical lordotic and cervical brow vertebral angle (CBVA). Unfortunately, one patient with loss of cranial fixation may be related to history of infection and lack of post-operative wound care. CONCLUSSION: Our cases conclude that Occipitocervical fixation is a safe technique that provides excellent fusion rate with good functional outcome and tolerable range of motion limitation. Due to its unique anatomy and technically demanding, serial post-operative monitoring evaluation of this procedure is paramount.