Department of Neurosurgery, Bicêtre Hospital, AP-HP, Le Kremlin-Bicêtre , France.
Department of Neurosurgery, Bretonneau Hospital, CHRU de Tours , France.
Oper Neurosurg (Hagerstown). 2024 Oct 1;27(4):424-430. doi: 10.1227/ons.0000000000001152. Epub 2024 Apr 10.
Patients with basilar invagination (BI) can be treated with several surgical options, ranging from simple posterior decompression to circumferential decompression and fusion. Here, we aimed at examining the indications and outcomes associated with these surgical strategies to devise a staged algorithm for managing BI.
We conducted a retrospective cohort study in 2 neurosurgical centers and included patients with a BI, as defined by a position of the dens tip at least 5 mm above the Chamberlain line. Other craniovertebral junction anomalies, such as atlas assimilation, platybasia, and Chiari malformations, were documented. C1-C2 stability was assessed with a dynamic computed tomography scan.
We included 30 patients with BI with a mean follow-up of 56 months (min = 12, max = 166). Posterior decompression and fusion (n = 8) was only performed in cases of obvious atlanto-axial instability (eg, increased atlanto-dental interval or hypermobility on flexion/extension), while anterior decompression (transoral or transnasal) was reserved to patients with lower cranial nerves deficits (eg, swallowing dysfunction) and irreducible anterior compression (n = 9). Patients with posterior signs (eg, Valsalva headaches) or myelopathy but without C1-C2 instability nor anterior signs were managed with an isolated foramen magnum decompression, with or without duraplasty (n = 13). Complications were more frequent for combined procedures, including neurological deterioriation (n = 4) and tracheostomy (n = 2), but reinterventions were more likely in patients undergoing posterior decompression alone (n = 3).
Patient selection is key to determine the appropriate surgical strategy for BI: In our experience, combined approaches are only needed for patients with irreducible and symptomatic anterior compression, while fusion should be restricted to patient with obvious signs of atlanto-axial instability. Other BI patients can be managed by foramen magnum decompression alone to minimize surgical morbidity.
颅底凹陷症（basilar invagination，BI）患者可采用多种手术方式进行治疗，包括单纯后路减压、寰枢椎全关节融合等。本研究旨在分析各种手术策略的适应证及疗效，为 BI 患者制定分步手术方案。
回顾性分析了两家神经外科中心的 BI 患者，纳入标准为枢椎齿状突尖端超过 Chamberlain 线至少 5mm。同时记录寰枢椎其他解剖异常，如寰椎融合、扁平颅底和 Chiari 畸形等。通过颈椎动力位 CT 评估寰枢椎稳定性。
共纳入 30 例 BI 患者，平均随访 56 个月（12~166 个月）。后路减压融合术仅用于明显寰枢椎不稳的患者（如齿状突-寰椎间隙增大或屈伸位活动度增加），而前路减压术（经口或经鼻）仅用于有颅神经损伤（如吞咽功能障碍）和寰枢椎前方压迫不可复位的患者（9 例）。仅表现为后颅窝症状（如valsalva 头痛）或脊髓病但无寰枢椎不稳且无前路症状的患者行单纯枕骨大孔减压术，部分患者同时行硬脊膜修补术（13 例）。联合手术组并发症更多，包括神经功能恶化（4 例）和气管切开（2 例），但后路减压组患者更易需要再次手术（3 例）。
患者选择是决定 BI 手术策略的关键因素：在我们的经验中，只有存在不可复位且有症状的寰枢椎前方压迫的患者才需要采用联合手术，而融合术仅适用于存在明显寰枢椎不稳的患者。对于其他 BI 患者，单纯行枕骨大孔减压术可降低手术风险。
