Yahanda Alexander T, Koueik Joyce, Ackerman Laurie L, Adelson P David, Albert Gregory W, Aldana Philipp R, Alden Tord D, Anderson Richard C E, Bauer David F, Bethel-Anderson Tammy, Bierbrauer Karin, Brockmeyer Douglas L, Chern Joshua J, Couture Daniel E, Daniels David J, Dlouhy Brian J, Durham Susan R, Ellenbogen Richard G, Eskandari Ramin, Fuchs Herbert E, Grant Gerald A, Graupman Patrick C, Greene Stephanie, Greenfield Jeffrey P, Gross Naina L, Guillaume Daniel J, Hankinson Todd C, Heuer Gregory G, Iantosca Mark, Iskandar Bermans J, Jackson Eric M, Jallo George I, Johnston James M, Kaufman Bruce A, Keating Robert F, Khan Nickalus R, Krieger Mark D, Leonard Jeffrey R, Maher Cormac O, Mangano Francesco T, Martin Jonathan, McComb J Gordon, McEvoy Sean D, Meehan Thanda, Menezes Arnold H, Muhlbauer Michael S, O'Neill Brent R, Olavarria Greg, Ragheb John, Selden Nathan R, Shah Manish N, Shannon Chevis N, Shimony Joshua S, Smyth Matthew D, Stone Scellig S D, Strahle Jennifer M, Tamber Mandeep S, Torner James C, Tuite Gerald F, Tyler-Kabara Elizabeth C, Wait Scott D, Wellons John C, Whitehead William E, Park Tae Sung, Limbrick David D, Ahmed Raheel
Departments of1Neurological Surgery and.
2Department of Neurological Surgery, University of Wisconsin at Madison, Wisconsin.
J Neurosurg Pediatr. 2024 Apr 5;34(1):66-74. doi: 10.3171/2024.1.PEDS23229. Print 2024 Jul 1.
Congenital anomalies of the atlanto-occipital articulation may be present in patients with Chiari malformation type I (CM-I). However, it is unclear how these anomalies affect the biomechanical stability of the craniovertebral junction (CVJ) and whether they are associated with an increased incidence of occipitocervical fusion (OCF) following posterior fossa decompression (PFD). The objective of this study was to determine the prevalence of condylar hypoplasia and atlas anomalies in children with CM-I and syringomyelia. The authors also investigated the predictive contribution of these anomalies to the occurrence of OCF following PFD (PFD+OCF).
The authors analyzed the prevalence of condylar hypoplasia and atlas arch anomalies for patients in the Park-Reeves Syringomyelia Research Consortium database who underwent PFD+OCF. Condylar hypoplasia was defined by an atlanto-occipital joint axis angle (AOJAA) ≥ 130°. Atlas assimilation and arch anomalies were identified on presurgical radiographic imaging. This PFD+OCF cohort was compared with a control cohort of patients who underwent PFD alone. The control group was matched to the PFD+OCF cohort according to age, sex, and duration of symptoms at a 2:1 ratio.
Clinical features and radiographic atlanto-occipital joint parameters were compared between 19 patients in the PFD+OCF cohort and 38 patients in the PFD-only cohort. Demographic data were not significantly different between cohorts (p > 0.05). The mean AOJAA was significantly higher in the PFD+OCF group than in the PFD group (144° ± 12° vs 127° ± 6°, p < 0.0001). In the PFD+OCF group, atlas assimilation and atlas arch anomalies were identified in 10 (53%) and 5 (26%) patients, respectively. These anomalies were absent (n = 0) in the PFD group (p < 0.001). Multivariate regression analysis identified the following 3 CVJ radiographic variables that were predictive of OCF occurrence after PFD: AOJAA ≥ 130° (p = 0.01), clivoaxial angle < 125° (p = 0.02), and occipital condyle-C2 sagittal vertical alignment (C-C2SVA) ≥ 5 mm (p = 0.01). A predictive model based on these 3 factors accurately predicted OCF following PFD (C-statistic 0.95).
The authors' results indicate that the occipital condyle-atlas joint complex might affect the biomechanical integrity of the CVJ in children with CM-I and syringomyelia. They describe the role of the AOJAA metric as an independent predictive factor for occurrence of OCF following PFD. Preoperative identification of these skeletal abnormalities may be used to guide surgical planning and treatment of patients with complex CM-I and coexistent osseous pathology.
I型 Chiari 畸形（CM-I）患者可能存在枕寰关节先天性异常。然而，尚不清楚这些异常如何影响颅颈交界区（CVJ）的生物力学稳定性，以及它们是否与后颅窝减压（PFD）后枕颈融合（OCF）发生率增加相关。本研究的目的是确定 CM-I 和脊髓空洞症患儿髁突发育不全和寰椎异常的患病率。作者还研究了这些异常对 PFD 后 OCF 发生（PFD+OCF）的预测作用。
作者分析了 Park-Reeves 脊髓空洞症研究联盟数据库中接受 PFD+OCF 的患者髁突发育不全和寰椎弓异常的患病率。髁突发育不全由枕寰关节轴角（AOJAA）≥130°定义。术前影像学检查确定寰椎融合和弓异常。将这个 PFD+OCF 队列与仅接受 PFD 的患者对照组进行比较。根据年龄、性别和症状持续时间，以 2:1 的比例将对照组与 PFD+OCF 队列进行匹配。
比较了 PFD+OCF 队列中的 19 例患者和仅接受 PFD 队列中的 38 例患者的临床特征和影像学枕寰关节参数。队列间人口统计学数据无显著差异（p>0.05）。PFD+OCF 组的平均 AOJAA 显著高于 PFD 组（144°±12° vs 127°±6°，p<0.0001）。在 PFD+OCF 组中，分别有 10 例（53%）和 5 例（26%）患者发现寰椎融合和寰椎弓异常。PFD 组未发现这些异常（n = 0）（p<0.001）。多因素回归分析确定了以下 3 个 CVJ 影像学变量可预测 PFD 后 OCF 的发生：AOJAA≥130°（p = 0.01）、斜坡轴角<125°（p = 0.02）和枕髁-C2 矢状垂直对线（C-C2SVA）≥5mm（p = 0.01）。基于这 3 个因素的预测模型能准确预测 PFD 后的 OCF（C 统计量 0.95）。
作者的结果表明，枕髁-寰椎关节复合体可能影响 CM-I 和脊髓空洞症患儿 CVJ 的生物力学完整性。他们描述了 AOJAA 指标作为 PFD 后 OCF 发生的独立预测因素的作用。术前识别这些骨骼异常可用于指导复杂 CM-I 和并存骨病变患者的手术规划和治疗。
