颅内肿瘤手术体位及入路

Intrinsic Cerebral Tumor Operative Approach and Patient PositionsThe surgical approach and patient positioning varies depending on the location of the intrinsic cerebral tumor and will be described separately.Frontal Lobe TumorsFrontal lobe tumors can essentially be divided into two different locations, depending on the proximity of the lesion to the midline. For those lesions that are found within 4 cm of the midline, the head of the patient can essentially be positioned straight up or turned slightly to the contralateral side after fixation with the three-point Mayfield head holder device. This also applies to tumors that are situated deeply within the anterior portion of the cingulated gyrus in front of the rolandic cortex. The incision extends from above the zygomatic arch to the anterior hairline and may be extended down onto the forehead slightly if the tumor is situated very far anteriorly. Should that be necessary, this incision is closed with subcuticular sutures and Steri-Strips (3M, St. Paul, MN) in that portion that involves the forehead (Fig. 1). For tumors situated more than 4 cm from the midline, positioning is facilitated by turning the head nearly 60 degrees toward the contralateral side, with a roll placed under the ipsilateral shoulder (Fig.2). The incision is essentially the same and, when this is done on the dominant hemisphere side, the scalp is infiltrated around the incision extending from the zygomatic arch above the ear and forward along the forehead in a circumferential pattern. When the tumor is within 1 to 2 cm of the rolandic cortex, it will be necessary to either expose the motor tract to facilitate stimulation-induced mapping or to stimulate the motor cortex with a subdural strip electrode should this area not be exposed because of an anteriorly placed craniotomy.额叶肿瘤额叶肿瘤依据病变距中线的距离基本上可分为2个不同的位置。

对于距中线4cm 内的病变，患者的头位可在Mayfield头架固定后垂直或向对侧轻度偏斜摆放。

这个头位同样可应用于rolandic皮层（即中央区）前的扣带回前部的深处肿瘤。

手术切口自颧弓至前发际，如果肿瘤非常靠前，则切口可向前额轻度延长。

如果必要的话，切口术后采用皮内缝合或创可贴(3M, St. Paul, MN)粘合，包括前额部(图1)。

对于距中线4cm之外的肿瘤，患者头部向对侧旋转约60°，同侧肩下垫圆枕（图2）。

当这是在优势半球端操作时，切口基本上是相同的，头皮切口周围浸润是从颧弓到耳朵上方再到前额部的圆周形式。

对于在rolandic皮层1-2cm内的肿瘤，有必要暴露运动束以诱导刺激定位，如果因为先前开颅而未能得到充分暴露，可以用硬膜下电极片刺激运动皮层而获得暴露。

FIGURE 1. Illustration showing the surgical position and scalp incision for frontal tumors within 4 cm of the midline.FIGURE 2. Illustration showing the surgical position and scalp incison for frontal tumors lateral to 4 cm of the midline.Temporal TumorsFor tumors involving the anterior half of the temporal lobe, the head is turned nearly 90 degrees contralateral to the lesion, with the head remaining parallel to the floor. When the lesion extends very far mesially near the cerebral peduncle and above the uncus, the head should be flexed toward the floor by 10 degrees. The incision extends from the zygomatic arch just above the pinna of the ear, and then superiorly toward the anterior hairline (Fig. 3, A and B). Should the tumor be located on the dominant hemisphere, the anesthetic scalp block again parallels the incision in a circumferential fashion (Fig. 4, A–C).。

When the tumor involves the posterior half of the temporal lobe, the head positioning remains the same but the incision extends from the zygomatic arch superiorly and thenposteriorly to end well behind the pinna of the ear in a horseshoe-type fashion. Again, should the exposure be on the dominant hemisphere side, the area of the incision is circumferentially infiltrated with local anesthetic.颞叶肿瘤对于前半颞叶内的肿瘤，病变侧头需向病变对侧旋转近90度，整个头部保持与地面平行。

当病变延伸很远，邻近中线附近的大脑脚及钩回之上，此时头部应向地板弯曲10度。

切口从颧弓延伸，沿耳廓上方，超越前发际线（图3，A和B）。

如果肿瘤位于优势半球，先行头皮阻滞麻醉，再以圆周形式平行延伸切口。

当肿瘤位于颞叶的后半部，头部定位仍然同前，但切口从颧弓上方开始，向后延伸，以马蹄形形式结束于耳廓后方。

同时，如果肿瘤位于优势半球侧，切口范围需用药物行局部浸润麻醉。

（图4，A-C）FIGURE 3. Illustrations showing the surgical position and scalp incision for anterior (A) and posterior (B) temporal lobe tumors.FIGURE 4. Illustrations showing the scalp incision and local anesthetic infusion for parietal tumor resection (A), frontotemporoinsular tumors (B), and anterior temporal tumors (C) under awake mapping conditions.Insular TumorInsular-based tumors provide a special challenge to the surgeon; thus, positioning must be adequate to achieve the desired goals of the surgical exposure and resection, depending on the location of the lesion above or below the sylvian fissure. For insular tumors in which the majority of the lesion is above the sylvian fissure, the patient’s head is turned a minimum of 60 degrees contralateral to the tumor, with the head extended nearly 15 degrees superiorly in relation to the floor. This allows for the resection to parallel the insular vessels, which are slanted toward the temporal lobe (Fig. 5A). When the majority of the insular tumor is located inferior to the sylvian fissure, the head should be turned nearly 90 degrees contralaterally and flexed inferiorly toward the floor nearly 15 degrees (Fig. 5B). This allows for direct visualization into the inferior aspect of the insula once the superior middle temporal gyrus is resected or retracted. This also provides access to the inferior portion of the uncinate fasciculus, which is facilitated by thehead-down position. If the lesion extends very far posteriorly, at least to the end of the posterior limb of the internal capsule, the head should not be turned 90 degrees but should remain 60 degrees from the straight up position to facilitate access to the posterior portion of the lesion. Should the insula be approached in the dominant hemisphere, the anesthetic block will again encompass in a circumferential fashion the incision, which typically extends from the zygomatic arch above the pinna of the ear and forward to the anterior hairline.岛叶肿瘤岛叶肿瘤对于外科医生来说是一个特殊的挑战，正因如此，体位的摆放必须适于获得理想的视野暴露和手术切除，取决于病变在外侧裂上还是外侧裂下。