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Hou X, Tian Y, Xu N, Li H, Yan M, Wang S, Li W. Overstrain on the longitudinal band of the cruciform ligament during flexion in the setting of sandwich deformity at the craniovertebral junction: a finite element analysis. Spine J 2023; 23:1721-1729. [PMID: 37385409 DOI: 10.1016/j.spinee.2023.06.387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/31/2023] [Accepted: 06/17/2023] [Indexed: 07/01/2023]
Abstract
BACKGROUND CONTEXT In the setting of "sandwich deformity" (concomitant C1 occipitalization and C2-3 nonsegmentation), the C1-2 joint becomes the only mobile joint in the craniovertebral junction. Atlantoaxial dislocation develops earlier with severer symptoms in sandwich deformity, which has been hypothesized to be due to the repetitive excessive tension in the ligaments between C1 and C2. PURPOSE To elucidate whether and how the major ligaments of the C1-2 joint are affected in sandwich deformity, and to find out the ligament most responsible for the earlier development and severer symptoms of atlantoaxial dislocation in sandwich deformity. STUDY DESIGN A finite element (FE) analysis study. METHODS A three-dimensional FE model from occiput to C5 was established using anatomical data from a thin-slice CT scan of a healthy volunteer. Sandwich deformity was simulated by eliminating any C0-1 and C2-3 segmental motion respectively. Flexion torque was applied, and the range of motion of each segment and the tension sustained by the major ligaments of C1-2 (including the transverse and longitudinal bands of the cruciform ligament, the alar ligaments, and the apical ligament) were analyzed. RESULTS Tension sustained by the longitudinal band of the cruciform ligament and the apical ligament during flexion is significantly larger in the FE model of sandwich deformity. In contrast, tension in the other ligaments is not significantly changed in the sandwich deformity model compared with the normal model. CONCLUSIONS Considering the importance of the longitudinal band of the cruciform ligament to the stability of the C1-2 joint, our findings implicate that the early onset, severe dislocation, and unique clinical manifestations of atlantoaxial dislocation in patients with sandwich deformity are mainly due to the enlarged force loaded on the longitudinal band of the cruciform ligament. CLINICAL SIGNIFICANCE The enlarged force loaded on the longitudinal band of the cruciform ligament can add to its laxity and thus reducing its ability to restrict the cranial migration of the odontoid process. This is in accordance with our clinical experience that dislocation of the atlantoaxial joint in patients with sandwich deformity is mainly craniocaudal, which means severer cranial neuropathy, Chiari deformity, and syringomyelia, and more difficult surgical treatment.
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Affiliation(s)
- Xiangyu Hou
- Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Rd, Haidian District, Beijing, China; Engineering Research Center of Bone and Joint Precision Medicine, 49 North Garden Rd, Haidian District, Beijing, China; Beijing Key Laboratory of Spinal Disease Research, 49 North Garden Rd, Haidian District, Beijing, China
| | - Yinglun Tian
- Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Rd, Haidian District, Beijing, China; Engineering Research Center of Bone and Joint Precision Medicine, 49 North Garden Rd, Haidian District, Beijing, China; Beijing Key Laboratory of Spinal Disease Research, 49 North Garden Rd, Haidian District, Beijing, China
| | - Nanfang Xu
- Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Rd, Haidian District, Beijing, China; Engineering Research Center of Bone and Joint Precision Medicine, 49 North Garden Rd, Haidian District, Beijing, China; Beijing Key Laboratory of Spinal Disease Research, 49 North Garden Rd, Haidian District, Beijing, China
| | - Hui Li
- Beijing Engineering and Technology Research Center for Medical Endoplants, Building 1, Yard 9, Chengwan Street, Haidian District, Beijing, China
| | - Ming Yan
- Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Rd, Haidian District, Beijing, China; Engineering Research Center of Bone and Joint Precision Medicine, 49 North Garden Rd, Haidian District, Beijing, China; Beijing Key Laboratory of Spinal Disease Research, 49 North Garden Rd, Haidian District, Beijing, China
| | - Shenglin Wang
- Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Rd, Haidian District, Beijing, China; Engineering Research Center of Bone and Joint Precision Medicine, 49 North Garden Rd, Haidian District, Beijing, China; Beijing Key Laboratory of Spinal Disease Research, 49 North Garden Rd, Haidian District, Beijing, China.
| | - Weishi Li
- Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Rd, Haidian District, Beijing, China; Engineering Research Center of Bone and Joint Precision Medicine, 49 North Garden Rd, Haidian District, Beijing, China; Beijing Key Laboratory of Spinal Disease Research, 49 North Garden Rd, Haidian District, Beijing, China
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Zhou LP, Zhao CH, Zhang ZG, Shang J, Zhang HQ, Ma F, Jia CY, Zhang RJ, Shen CL. Characteristics and evaluation of C1 posterior arch variation for transpedicular screw placement between patients with and without basilar invagination. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2023; 32:3547-3560. [PMID: 37530951 DOI: 10.1007/s00586-023-07873-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/24/2023] [Accepted: 07/22/2023] [Indexed: 08/03/2023]
Abstract
BACKGROUND C1 transpedicular screw (C1TS) placement provided satisfactory pullout resistance and 3D stability, but its application might be limited in patients with basilar invagination (BI) due to the high incidences of the atlas anomaly and vertebral artery (VA) variation. However, no study has explored the classifications of C1 posterior arch variations and investigated their indications and ideal insertion trajectories for C1TS in BI. PURPOSE To investigate the bony and surrounding arterial characteristics of the atlas, classify posterior arch variations, identify indications for C1TS, evaluate ideal insertion trajectories for C1TS in BI patients without atlas occipitalization (AO), and compare them with those without BI and AO as control. METHODS A total of 130 non-AO patients with and without BI (52 patients and 78 patients, respectively) from two medical centers were included at a 1:1.5 ratio. The posterior arch variations were assessed using a modified C1 morphological classification. Comparisons regarding the bony and surrounding arterial characteristics, morphological classification distributions, and ideal insertion trajectories between BI and control groups were performed. The subgroup analyses based on different morphological classifications were also conducted. In addition, the factors possibly affecting the insertion parameters were investigated using multiple linear regression analyses. RESULTS The BI group was associated with significantly smaller lateral mass height and width, sagittal length of posterior arch, pedicle height, vertical height of posterior arch, and distance between VA and VA groove (VAG) than control group. Four types of posterior arch variations with indications for different screw placement techniques were classified; Classifications I and II were suitable for C1TS. The BI cohort showed a significantly lower rate of Classification I than the control cohort. In the BI group, the subgroup of Classification I had significantly larger distance between the insertion point (IP) and inferior aspect of the posterior arch. In addition, it had the narrowest width along ideal screw trajectory, but a significantly more lateral ideal mediolateral angle than the subgroup of Classification II. Multiple linear regression indicated that the cephalad angle was significantly associated with the diagnosis of BI (B = 3.708, P < 0.001) and sagittal diameter of C1 (B = 3.417, P = 0.027); the ideal mediolateral angle was significantly associated with BMI (B = 0.264, P = 0.031), sagittal diameter of C1 (B = - 4.559, P = 0.002), and pedicle height (B = - 2.317, P < 0.001); the distance between the IP and inferior aspects of posterior arch was significantly associated with age (B = - 0.002, P = 0.035), BMI (B = - 0.007, P = 0.028), sagittal length of posterior arch (B = - 0.187, P = 0.032), pedicle height (B = - 0.392, P < 0.001), and middle and lower parts of posterior arch (B = 0.862, P < 0.001). CONCLUSION The incidence of posterior arch variation in BI patients without AO was remarkably higher than that in control patients. The insertion parameters of posterior screws were different between the morphological classification types in BI and control groups. The distance between VA V3 segments and VAG in BI cohort was substantially smaller than that in control cohort. Preoperative individual 3D computed tomography (CT), CT angiography and intraoperative navigation are recommended for BI patients receiving posterior screw placement.
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Affiliation(s)
- Lu-Ping Zhou
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Chen-Hao Zhao
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Zhi-Gang Zhang
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Jin Shang
- Department of Radiology, The First Affiliated Hospital of University of Science and Technology of China, 107 Huanhudong Road, Hefei, 230031, Anhui, China
| | - Hua-Qing Zhang
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Fang Ma
- Center for Scientific Research, Anhui Medical University, 81 Meishan Road, Hefei, 230032, Anhui, China
| | - Chong-Yu Jia
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China
| | - Ren-Jie Zhang
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China.
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China.
| | - Cai-Liang Shen
- Department of Orthopedics and Spine Surgery, The First Affiliated Hospital of Anhui Medical University, 218 Jixi Road, Hefei, 230022, Anhui, China.
- Laboratory of Spinal and Spinal Cord Injury Regeneration and Repair, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui, China.
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Xiao H, Huang Z, Xu P, Lin J, Zhu Q, Ji W. Anterior Transarticular Crossing Screw Fixation for Atlantoaxial Joint Instability: A Biomechanical Study. Neurospine 2023; 20:940-946. [PMID: 37798988 PMCID: PMC10562216 DOI: 10.14245/ns.2346472.236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/10/2023] [Accepted: 06/20/2023] [Indexed: 10/07/2023] Open
Abstract
OBJECTIVE To evaluate the biomechanical stability of anterior transarticular crossing screw (ATCS) and compare it with anterior transarticular screw (ATS) which may provide basic evidence for clinical application. METHODS Eight human fresh cadaveric specimens (occiput-C4) were tested with 5 conditions including the intact status, the injury status (type II odontoid fracture), the injury+ATS fixation status (traditional bilateral ATS fixation); the injury+unilateral ATCS fixation status; and the injury+bilateral ATCS fixation status. Specimens were applied to a pure moment of 1.5 Nm in flexion-extension, lateral bending, and axial rotation, respectively. The range of motions (ROMs) and the neutral zones (NZs) of C1 to C2 segment were calculated and compared between 5 status. RESULTS ATS and ATCS fixations significantly reduced the motions in all directions when compared with the intact and injury statues (p < 0.05). In flexion-extension, the ROMs of ATS, unilateral ATCS, and bilateral ATCS were 4.7° ± 2.5°, 4.1° ± 1.9°, and 3.2° ± 1.2°, respectively. Bilateral ATCS resulted in a significant decrease in ROM in flexion-extension when compared with ATS and unilateral ATCS (p = 0.035 and p = 0.023). In lateral bending and axial rotation, there was no significant difference in ROM between the 3 fixations (p > 0.05). Three fixations resulted in similar NZs in all directions (p > 0.05). CONCLUSION ATCS is a biomechanically effective alternative or supplemental method for atlantoaxial instability.
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Affiliation(s)
- Hang Xiao
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhiping Huang
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Panjie Xu
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Junyu Lin
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Orthopaedics and Traumatology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Qingan Zhu
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Wei Ji
- Division of Spinal Surgery, Department of Orthopaedics, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Department of Orthopaedics, Yunfu People’s Hospital, Yunfu, China
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Xu N, Tian Y, Yue L, Yan M, Hung KL, Hou X, Li W, Wang S. Clinical and Surgical Characteristics of Patients with Atlantoaxial Dislocation in the Setting of "Sandwich Fusion": A Case-Control Study. J Bone Joint Surg Am 2023; 105:771-778. [PMID: 36827380 DOI: 10.2106/jbjs.22.01004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
BACKGROUND Patients with "sandwich" fusion (concomitant C1 occipitalization and C2-C3 nonsegmentation), a subtype of Klippel-Feil syndrome, are at particular risk for developing atlantoaxial dislocation (AAD). However, the clinical and surgical characteristics of AAD in patients with sandwich fusion have not been clearly defined. METHODS A retrospective case-control study with a large sample size and a minimum 2-year follow-up was performed. From 2000 to 2018, 253 patients with sandwich AAD underwent a surgical procedure; these patients constituted the case group, and a matching number of patients with non-sandwich AAD were randomly selected to form the control group. Clinical data from electronic medical records and various imaging studies were analyzed and compared. The Japanese Orthopaedic Association (JOA) scale was used to evaluate neurological function. RESULTS Patients with sandwich AAD, compared with patients with non-sandwich AAD, had symptom onset at a younger age (34.8 compared with 42.8 years; p < 0.001) and had a higher likelihood for myelopathy (87.4% compared with 74.7%; p < 0.001). Patients with sandwich AAD had a higher incidence of lower cranial nerve palsy (7.9% compared with 0.0%; p < 0.001), a lower preoperative JOA score (13.4 compared with 14.2; p < 0.001), and higher incidences of accompanying Type-I Chiari malformation (20.9% compared with 1.2%; p < 0.001) and syringomyelia (21.3% compared with 1.6%; p < 0.001). Finally, patients with sandwich AAD had higher likelihoods of undergoing transoral release (28.5% compared with 5.1%; p < 0.001) and use of salvage fixation techniques (34.4% compared with 6.3%; p < 0.001), and had lower postoperative results for the JOA score (14.9 compared with 15.9; p < 0.001) and improvement rate (43.8% compared with 58.2%; p < 0.001). CONCLUSIONS Patients with sandwich AAD demonstrated distinct clinical manifestations. Versatility involving the use of various internal fixation techniques and transoral release procedures was frequently required in the surgical management of these patients, and meticulous and personalized preoperative planning would be of paramount importance. LEVEL OF EVIDENCE Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
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Affiliation(s)
- Nanfang Xu
- Department of Orthopaedics, Peking University Third Hospital, Beijing, People's Republic of China.,Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, People's Republic of China.,Beijing Key Laboratory of Spinal Disease Research, Beijing, People's Republic of China
| | - Yinglun Tian
- Department of Orthopaedics, Peking University Third Hospital, Beijing, People's Republic of China.,Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, People's Republic of China.,Beijing Key Laboratory of Spinal Disease Research, Beijing, People's Republic of China
| | - Lihao Yue
- Peking University Health Science Center, Beijing, People's Republic of China
| | - Ming Yan
- Department of Orthopaedics, Peking University Third Hospital, Beijing, People's Republic of China.,Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, People's Republic of China.,Beijing Key Laboratory of Spinal Disease Research, Beijing, People's Republic of China
| | - Kan-Lin Hung
- Peking University Health Science Center, Beijing, People's Republic of China
| | - Xiangyu Hou
- Department of Orthopaedics, Peking University Third Hospital, Beijing, People's Republic of China
| | - Weishi Li
- Department of Orthopaedics, Peking University Third Hospital, Beijing, People's Republic of China.,Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, People's Republic of China.,Beijing Key Laboratory of Spinal Disease Research, Beijing, People's Republic of China
| | - Shenglin Wang
- Department of Orthopaedics, Peking University Third Hospital, Beijing, People's Republic of China.,Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, People's Republic of China.,Beijing Key Laboratory of Spinal Disease Research, Beijing, People's Republic of China
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Hou Z, Jian Q, Fan W, Zhao X, Wang Y, Fan T. Application of C2 subfacetal screws for the management of atlantoaxial dislocation in patients with Klippel-Feil syndrome characterized by a narrow C2 pedicle and high-riding vertebral artery. J Orthop Surg Res 2022; 17:495. [PMCID: PMC9670565 DOI: 10.1186/s13018-022-03391-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 11/06/2022] [Indexed: 11/18/2022] Open
Abstract
Abstract
Objective
This study aims to investigate the clinical application and feasibility of C2 subfacetal screws in patients with Klippel-Feil syndrome (KFS), narrow C2 pedicles, and high-riding vertebral arteries (HRVAs).
Methods
The clinical data of seven patients with KFS, atlantoaxial dislocation, narrow C2 pedicles, and HRVAs treated with C2 subfacetal screws were analyzed in this retrospective study. The internal height, isthmus height, and pedicle width of C2 vertebra were measured using preoperative computed tomography (CT). Subfacetal screws were inserted for 7 patients (12 sides). The position and length of the screws were observed using postoperative CT. Intraoperative dura mater and vertebral artery (VA) injuries were recorded. Bone fusion was observed using follow-up CT.
Results
The internal height was 10.5 ± 3.2 mm, the isthmus height was 3.7 ± 1.8 mm, the pedicle width was 3.0 ± 1.4 mm, and the screw length was 19.7 ± 1.5 mm. All patients had HRVAs and narrow pedicles. No injury to the dura mater and vertebral artery (VA) occurred in this group of patients. Bone fusion was achieved in all patients during follow-up.
Conclusions
In patients with KFS, HRVA, and a narrow C2 pedicle, there is sufficient space below the C2 articular surface for screw insertion. When the pedicle is narrow and the C2 pedicle screw is not suitable for placement due to possible injury to the VA, subfacetal screws are a feasible alternative.
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