Miura Kousei, Koda Masao, Funayama Toru, Takahashi Hiroshi, Yamazaki Masashi
Department of Orthopaedic Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, JPN.
Cureus. 2021 Jul 25;13(7):e16610. doi: 10.7759/cureus.16610. eCollection 2021 Jul.
Conventional fluoroscopic guidance can provide enough information to precisely insert an occipital screw in ordinary cases. However, the occipital screw creates a potential risk of dural venous sinus injury or thrombosis. In some cases, with dural sinus variation, surgeons must especially be cautious to avoid its injury. We present a rare case of proper occipital screw placement using a navigation system for a pathological odontoid fracture with a high risk of dural venous sinus injury because of anatomical variations in the transverse and occipital sinuses. A 60-year-old man who underwent thyroidectomy at the age of 37 years for thyroid carcinoma developed acute neck pain and quadriparesis due to falling out of bed. He urgently underwent closed reduction and temporary immobilization with a halo-vest for a pathological odontoid fracture and atlantoaxial dislocation. Preoperative contrast-enhanced CT showed an absent right transverse sinus and a prominent occipital sinus as variations of the dural venous sinuses. Occipito-C7 fusion surgery was performed without intraoperative active venous bleeding or postoperative brain disorder by using a navigation system for the occipital screw placement to avoid injury to the dural sinus. Postoperative computed tomography showed bi-cortical occipital screw placement avoiding the prominent occipital sinus. The patient's postoperative course was uneventful. In this case, although rigid occipito-cervical fixation using bi-cortical occipital screws was needed for the pathological odontoid fracture, the variation of the occipital sinus created a high risk of injury during occipital screw placement with conventional fluoroscopic guidance. There is an anatomical variation of the dural venous sinuses between individuals. Prominent occipital sinus injury may notably cause fatal complications such as massive bleeding or occlusion. Thus, we safely inserted the occipital screws using a navigation system that enabled us to avoid occipital venous sinus injury. Occipital screw placement with a navigation system can be a better option to prevent dural venous sinus injury in cases where there is variation in the dural venous sinuses, such as with a prominent occipital venous sinus.
在普通病例中，传统的透视引导可为精确置入枕骨螺钉提供足够信息。然而，枕骨螺钉存在硬脑膜静脉窦损伤或血栓形成的潜在风险。在某些情况下，由于硬脑膜窦变异，外科医生必须格外小心以避免损伤。我们报告一例罕见病例，对于因横窦和枕窦解剖变异而存在硬脑膜静脉窦损伤高风险的病理性齿状突骨折，使用导航系统正确置入枕骨螺钉。一名60岁男性，37岁时因甲状腺癌接受了甲状腺切除术，因从床上跌落出现急性颈部疼痛和四肢瘫。他因病理性齿状突骨折和寰枢椎脱位紧急接受了闭合复位并用头环背心临时固定。术前增强CT显示硬脑膜静脉窦变异，右侧横窦缺如，枕窦突出。通过使用导航系统置入枕骨螺钉以避免损伤硬脑膜窦，进行了枕骨至C7融合手术，术中无活动性静脉出血，术后无脑功能障碍。术后CT显示枕骨螺钉双皮质置入，避开了突出的枕窦。患者术后恢复顺利。在本病例中，尽管病理性齿状突骨折需要使用双皮质枕骨螺钉进行坚强的枕颈固定，但枕窦变异在传统透视引导下置入枕骨螺钉时造成了高损伤风险。个体之间硬脑膜静脉窦存在解剖变异。突出的枕窦损伤可能显著导致致命并发症，如大量出血或闭塞。因此，我们使用导航系统安全地置入了枕骨螺钉，使我们能够避免枕静脉窦损伤。在硬脑膜静脉窦存在变异，如枕静脉窦突出的情况下，使用导航系统置入枕骨螺钉可能是预防硬脑膜静脉窦损伤的更好选择。
