Facet-occiput slope angle: A novel predictor of cage placement feasibility during surgery in basilar invagination patients
Mirwais Alizada,
Yuqiang Wang,
Yao Zhao,
Shuhao Zhang,
Gati Hayatullah,
Min Zhang,
Shuxin Li,
Mujahid Alizada,
Muhibullah Alizada,
Kejdi Lalaj,
Kerong Yang,
Ismatullah Soufiany,
Limin Wang,
Yilin Liu
Affiliations
Mirwais Alizada
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Yuqiang Wang
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Yao Zhao
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Shuhao Zhang
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Gati Hayatullah
Department of Gynecology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Min Zhang
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Shuxin Li
Department of Imaging Diagnosis, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Mujahid Alizada
Department of Neurosurgery, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, Fujian, PR China
Muhibullah Alizada
Department of Interventional Radiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Kejdi Lalaj
Department Maxillofacial Surgery, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Kerong Yang
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China
Ismatullah Soufiany
Department of Neurology, Nanjing First Hospital, Nanjing, Jiangsu, PR China
Limin Wang
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China; Corresponding author.Department of orthopedics, First Affiliated Hospital of Zhengzhou University, No.1 Jianshe East Road, Zhengzhou, 450052, PR China.
Yilin Liu
Department of Orthopedics, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, PR China; Corresponding author.Department of orthopedics, First Affiliated Hospital of Zhengzhou University, No.1 Jianshe East Road, Zhengzhou, 450052, PR China.
Background and aim: Direct posterior reduction and manipulation of the C1-2 joints, accompanied by placement of spacers, is the state-of-the-art technique for treating basilar invagination (BI) and atlantoaxial dislocation (AAD). The hindrance of occiput to reaching up to the true atlantoaxial facets (AAF) during the surgery remains challenging for cage placement. The aim of this study was to explore an objective and precise method of measuring the effect of the hindrance of occiput to reaching up to the true AAF and cage placement during surgery. Method: We collected the clinico-imaging data of 58 patients with BI and AAD (Group A) who underwent surgery in our hospital, and 78 control cohorts (Group B) were retrieved retrospectively. We measured facet-occiput slope angle (FOSA) in midsagittal CT. Patients were positioned prone for surgery based on preoperative flexion O–C2a, and access to the true AAF was observed intraoperatively. The cut-off value of FOSA for the feasibility of cage placement in BI and AAD patients was appointed when access to the true AAF was impossible due to the hindrance of occiput during surgery. Results: The cut-off value of FOSA for the feasibility of cage placement was 34o with an area under the curve AUC of 0.800 (95 % CI: 0.672–0.928, P 34o, reaching up to the true AAF and 3D-printed cage placement was impossible. FOSA was negative in Group A and positive in Group B, significantly larger in females compared to males in both groups and significantly larger postoperatively in Group A. Conclusion: FOSA can objectively measure the feasibility of cage placement when the patient is positioned prone per preoperative flexion O–C2a. A FOSA >34o is contraindication for cage placement.
