文献笔记（553）髂内静脉分支的解剖变异和在复杂盆腔手术中的临床意义

背景：在高位骶骨切除术和盆腔侧方廓清术中，在骶前区域游离髂外和髂内静脉,对于避免意外损伤和严重出血非常关键。以往没有对髂外静脉分支的解剖变异进行描述，而髂内静脉分支存在多个分型。

目的：用软防腐处理的尸体来澄清髂内静脉系统的解剖

条件、患者和措施：在泰国朱拉隆功大学开展，检查了来自20个人类尸体的40个髂静脉系统（10男10女）。蓝色树脂染料灌注到下腔静脉，凸显髂静脉系统，仔细进行分离，并追踪到引流器官。

主要结局指标：记录并分析髂内静脉分支及其瓣膜系统。

结果：髂外静脉经典上接受2个靠近腹股沟韧带的分支（腹壁下静脉和旋髂深静脉）。但是，15具（75%）尸体在骶前区域发现20个存在髂外静脉分支。每个分支的平均直径为4.0 -0.35mm，72%为侧方起源。我们提出一个简化的髂内静脉变异分型：I型共12具尸体（60%），此型中单独的一根髂内静脉加入单独的髂外静脉，然后引流到髂总静脉；II型共7具尸体（35%）髂内静脉有两支；III型共1具尸体（5%），双侧髂内静脉先汇入共干，然后加入髂外静脉形成髂总静脉分叉。

局限性：本研究受体尸体解剖数量的限制。

结论：髂外静脉在骶前区域存在分支的发生率很高，这一点既往未报道，但在复杂盆腔手术中具有重要意义。提出了一个简化的髂内静脉变异分型。

To avoid uncontrolled hemorrhage, vascular exposure and isolation of the external iliac vein and internal iliac vein is helpful. In performing this step, we have frequently encountered multiple previously undescribed anatomical variations of EIV tributaries in the presacral region. It is important to better understand the anatomy of these tributaries, because they should be preemptively ligated to avoid bleeding. In addition, surgeons routinely ligate the IIV and its tributaries sequentially to devascularize the pelvis during exenterations and enable safe dissection of the lateral sacral margin during sacrectomies.

为了避免难以控制的出血，暴露游离髂外静脉和髂内静脉是有帮助的。在进行这一步时，我们常常在骶前区域遇到以往未描述的多个解剖变异。更好地理解这些变异的解剖非常重要，因为要预先结扎这些静脉以避免出血。此外，手术医生常规结扎髂内静脉及其分支，从而在廓清术中使盆腔去血供,可以在骶骨切除术中安全分离骶骨外侧边缘。

A simple, concise, yet surgically relevant system of approach the dissetion of IIV is needed to promote its utilization in clinical practice.

需要一个简单，简明且手术相关的系统，进行髂内静脉分离，促进其在临床中的应用。

The EIV classically arises from 2 tributaries(deep iliac circumflex and deep epigastric veins) near the inguinal ligament, with no tributaries within the presacral area. Of 40 iliac venous systems, we found 20(50%) with tributaries arising from the EIV within the presacral area(15/20 cadavers, 75%). They were asymmetrical on either side in all cases. In terms of decreasing frequency, they were the sacroiliac joint, pelvic side wall tributary, communicating tributary between the ipsilateral IIV and EIV, tributary to S1 root, iliolumbar tributary, and posterior trunk draining several of the above tributaries. The mean diameter of each tributary was 4.0 -0.35mm. They arose laterally 72% of the time, whereas 17% and 11% arose posteriorly and medially.

经典地髂外静脉起源于两个靠近腹股沟韧带的分支，旋髂深静脉和腹壁深静脉，在骶前区域没有分支。在40个髂内静脉系统中，我们发现20个（50%）在骶前区域有髂外分支（15/20,75%）。它们在所有病例中在双侧均不对称。按照发生频率，一次是骶髂关节，盆侧壁分支，单侧髂内静脉和髂外静脉的交通支，到S1神经根的分支，髂腰分支和引流上面一些分支的后干。每个分支的平均直径是4.0 -0.35mm。它们起源于外侧占72%，17%和11%起源于后方和内侧。

Three main patterns of IIV were observed, as illustarted in Figure 3. Pattern 1 describes the normal anatomy where a single IIV joins a single EIV to drain into the ipsilateral CIV. This was identified in 29 iliac venous systmes in 60% of cadavers. Pattern 2, where duplicated IIV tributaries join a single EIV to drain into the ipsilateral CIV, was found in 7(35%) cadavers. Within pattern 2, 4 cadavers had right IIV duplication, 1 had left IIV duplication, and 2 had bilateral IIV duplication. In pattern 3, the left and right IIV drain into a midline median sacral vein to form a common trunk, with no CIV. This is present in 1(5%)cadaver.

如图3所示，可以观察到髂内静脉的三个类型。I型描述正常解剖，一个单独的髂内静脉汇入一个单独的髂外静脉，引流到单侧髂总静脉，这在60%的尸体上共29个髂静脉系统中观察到。II型，双重髂内静脉分支汇合成一个髂内静脉，引流到同侧的髂总静脉，在7具尸体中凹陷。在II型中，4具尸体有右侧重复髂内静脉，1具有左侧重复髂内静脉，2具有双侧重复髂内静脉。在III型中，左侧和右侧髂内静脉引流到中间地骶中静脉形成共干，没有髂总静脉，出现在1具尸体中。

External iliac vein isolation opens a window of safety to visualize the lumbosacral nerve trunk and sacroiliac joint, and prevents inadvertent avulsion and injury during anterior and posterior osteotomies. If not slung away and protected, unintentional injury to the EIV may predispose to deep vein thrombosis of the lower limb.

髂外静脉游离后，打开了一个安全窗，可以看到腰骶神经干和骶髂关节，防治在前后切骨时意外撕裂损伤。如果不拉开保护，意外损伤髂外静脉可能会诱发下肢深静脉血栓形成。

Failure to isolate the communicating tributaries may result in incomplete disconnection of the epidural venous plexus and iliac venous systems, resulting in bleeding that is difficult to control if not preemptively addressed. Because the EIV tributaries are small with a mean diameter of 4.0mm, they are not readily identified on routine preoperative multidetector CT scans. They are also asymmetrical on either side, emphasizing the need for extra vigilance during dissection.

游离交通支失败可能导致皮下静脉丛和髂静脉系统的阻断不完全，如果不处理会导致难以控制的出血。因为髂外静脉分支很小直径约4mm，常规多探头术前CT难以发现，它们往往双侧也不对称，因此手术中需要特别注意。

Based on findings from this study, we have modified our surgical approach to EIV isolation. After controlling the overlying internal iliac artery, dissection begins lateral to the EIV, where the majority of tributaries are found, and where there is usually less  tumor-related inflammatin. The posterior and medial tributaries are then systematically ligated until the EIV is skeletonized.

根据上面本研究的发现，我们改良了髂外静脉游离的过程。在控制了表面覆盖的髂外动脉后，在髂外静脉外侧分离，可以找到大多数分支，而且此处往往较少肿瘤相关炎症。然后分离结扎后方和内侧分支，直至骨骼化髂外静脉。

来源：Kanjanasilp P, Ng JL, Kajohnwongsatit K, Thiptanakit C, Limvorapitak T, Sahakitrungruang C. Anatomical Variations of Iliac Vein Tributaries and Their Clinical Implications During Complex Pelvic Surgeries. Dis Colon Rectum. 2019 Jul;62(7):809-814. doi: 10.1097/DCR.0000000000001335. PMID: 31188181.

点评：本文的最大亮点在于解剖和临床应用的结合，不仅阐明了解剖数据，而且阐明了这些数据在实际应用中的价值。