Izeki Masanori, Neo Masashi, Fujibayashi Shunsuke, Takemoto Mitsuru, Otsuki Bungo, Watanabe Mutsumi, Koizumi Koji, Matsuda Akira, Nagai Koutatsu, Matsuda Shuichi
Department of Orthopaedic Surgery, Kyoto University, Japan.
Spine (Phila Pa 1976). 2013 Aug 15;38(18):E1149-55. doi: 10.1097/BRS.0b013e31829c0e1a.
Prospective descriptive study.
To verify the feasibility and utility of evaluating venous sinuses (VSs) using computed tomography venography (CTV) concomitant with preoperative CT angiography (CTA) for safe occipital screw fixation.
Preoperative evaluation of the vertebral artery by CTA is indispensable in occipitocervical spinal instrumentation surgery. Despite accumulating evidence showing the potential of CTV, no studies have reported the usefulness of concomitant use of CTV and CTA before placement of occipital plate-screw constructs.
We analyzed 30 consecutive patients who underwent CTV simultaneously with CTA. First, we investigated VS anatomy in individual cases and classified the continuity patterns of relevant VSs. Subsequently, we evaluated the probable risk zones for VS injury, from the viewpoint of occipital screw insertion.
VSs can be clearly visualized using CTV simultaneously with CTA examination without significant increase of radiation exposure or extra workload for radiographical technicians. VS continuity was classified into 4 categories: the confluence type (n = 9), bifurcation type (n = 8), transverse type (n = 11), and others (n = 2). The confluence of sinuses and their relevant VSs were greatly variable between individuals, and occasionally, some cases with high-risk morphology for VS injury in occipital screw placement were observed.
Our findings indicate that there is no universal position for safe insertion of occipital screws that is applicable to all individuals. It is risky to determine optimal screw placement, only on the basis of traditional cadaveric information such as occipital bone thickness and several external bony landmarks. Spine surgeons must recognize that VS injury may occasionally lead to life-threatening complications. The detailed information on VSs obtained by preoperative CTV examination combined with CTA in individual cases can be useful in preoperative planning and can contribute greatly to the improvement of surgical safety.
前瞻性描述性研究。
验证在术前进行计算机断层血管造影（CTA）时同时使用计算机断层静脉造影（CTV）评估静脉窦（VSs）对于安全枕骨螺钉固定的可行性和实用性。
在枕颈脊柱器械手术中，通过CTA对椎动脉进行术前评估是必不可少的。尽管越来越多的证据显示CTV具有潜在作用，但尚无研究报道在放置枕骨板螺钉结构之前同时使用CTV和CTA的实用性。
我们分析了30例同时接受CTV和CTA检查的连续患者。首先，我们研究了个体病例中的VS解剖结构，并对相关VSs的连续性模式进行分类。随后，我们从枕骨螺钉插入的角度评估了VS损伤的可能风险区域。
在不显著增加辐射暴露或给放射技师增加额外工作量的情况下，使用CTV可在CTA检查时同时清晰显示VSs。VS连续性分为4类：汇合型（n = 9）、分叉型（n = 8）、横型（n = 11）和其他类型（n = 2）。静脉窦及其相关VSs的汇合情况在个体之间差异很大，偶尔会观察到一些在枕骨螺钉置入时具有VS损伤高风险形态的病例。
我们的研究结果表明，不存在适用于所有个体的安全插入枕骨螺钉的通用位置。仅根据枕骨厚度和几个外部骨性标志等传统尸体信息来确定最佳螺钉置入位置是有风险的。脊柱外科医生必须认识到VS损伤偶尔可能导致危及生命的并发症。术前在个体病例中通过CTV检查结合CTA获得的VS详细信息可有助于术前规划，并可极大地提高手术安全性。
2级。
