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本期为Worldneurosurgery定期连载的河南省人民医院张长远医师终审的《动脉瘤大师级神作--Seven Aneurysms》著作第三期。本期主要内容为 脑牵拉，《Seven Aneurysms 》系列内容包括 Section I The Tenets：1. 在显微镜下操作；2. 蛛网膜下腔的解剖；3.脑牵拉；4.血管控制；5.临时阻断；6.永久夹闭；7.检测；8.脑皮层造瘘；9.术中破裂。Section II The Approaches: 10.翼点入路; 11.眶颧入路; 12.前纵裂入路; 13.远外侧入路。Section IIIThe Seven Aneurysms: 14.后交通动脉瘤; 15.大脑中动脉瘤; 16.前交通动脉瘤; 17.眼动脉动脉瘤; 18.胼周动脉瘤; 19.基底动脉分叉动脉瘤; 20.小脑后下动脉动脉瘤。 《Seven Aneurysms》著作系列回顾： 第一期：神外医师基本功-- 在显微镜下操作技巧----Seven Aneurysms系列 第二期：神外医师基本功--蛛网膜下腔的解剖---Seven Aneurysms系列 第三期：Brain Retraction--脑牵拉 Retraction Without Retractors--无牵开器牵拉 Brain retraction is bad. It can raise brain tissue pressure, reduce cerebral perfusion locally, hide critical anatomy, and injure neurovascular structures. However, subarachnoid corridors of the brain are often too narrow to be navigated without some retraction. Therefore, it needs to be applied discriminately and with finesse. 牵拉对脑组织是有害处的。它可以增加脑组织的受压、减少局部脑灌注、遮挡关键的解剖、损伤神经血管结构。然而，如果没有牵拉，大脑蛛网膜下腔往往过于狭窄而无法进行显露及手术。因此，需要对牵拉有区别、有策略地应用。 The sucker and suction hand have an underappreciated role as a roving retractor. While drying the surgical field, the sucker also applies countertraction at the point of dissection with its tip and gentle pressure to the brain with its shaft. The bullet-tipped No. 7 or No. 5 microsuction is smooth and atraumatic. Suction strength is regulated by rolling the thumb forward to cover the keyhole fenestration at the thumb grip for more suction, or backward to uncover the fenestration for less suction. The thumb rests in a middle position that partially covers the hole, and a constant whistling noise should be heard at all times. When the whistling disappears, the thumb may be covering the fenestration and suction may draw in adjacent structures. The sucker is malleable; the shaft is straightened to follow the dissection plane and curved gently to the hand. Connecting the sucker to soft silicone tubing keeps it mobile in the hand, whereas stiff plastic tubing creates resistance. 吸引器和吸引器柄有一个作用被忽略了，即牵开作用。在保持术野清晰无血同时，吸引器头部在分离部位可以进行对抗牵拉，吸引器柄轻压脑组织可以使之移位。5、7号显微吸引器的圆头是光滑、无损伤的。吸力大小是由拇指向前移阻塞侧孔来调大，或向后打开侧孔以减小。拇指一般停留在中间位置（部分阻塞侧孔），此时可以一直听到一种持续的哨音。当哨音消失时，拇指可能遮挡了侧孔，或者吸引器可能吸入了邻近结构。吸引器具有可塑性：吸引器杆在分离的界面是直的、在靠近手的部位稍稍弯曲。吸引器头连接柔软的硅胶管以便使它在手中容易移动，而硬的塑料管会对手的移动产生阻力。 A properly adjusted sucker naturally complements the dissecting instrument. These instruments lie directly opposite one another at the depth of the field; the sucker provides microretraction for each maneuver of the dissecting instrument, and, unlike a fixed retractor blade, the sucker adjusts constantly to the dissection. Lateral pressure with the sucker provides countertraction when cutting tissue, and retracts tissues to facilitate visualizing the dissection plane. The sucker can cross to the side of the dissecting instrument to apply contralateral pressure. A dynamic suction hand substantially reduces the need for a fixed retractor. 经过适当调整的吸引器管可以作为解剖、分离器械的有效补充，这些器械在术野深部分别位于相对的两侧，当手术器械进行分离操作时，吸引器提供相对应的轻微牵拉力，和固定的牵开器叶片不同，吸引器管可以根据分离的需要随时调整牵开的力量及方向。切除组织时，吸引器管的侧向力量可以提供对抗牵拉力，并且可以牵拉组织帮助解剖、分离界面的显露。一个灵活的吸引器可以有效地替代固定牵开器。 In addition to microretraction with the sucker tip, the sucker shaft can function as a slim retractor blade. Instead of positioning the shaft in the dissection corridor, laying the shaft against the brain gently retracts it and opens the corridor like a funnel. The position of the tip is not affected by this lateral hand movement. Like sucker tip retraction, shaft retraction is also dynamic and adapts to the changing needs of the dissection. Dissecting instruments in the dominant hand, like the microscissors or bipolar forceps, can also function as retractors. The shafts of these instruments can retract their side of the surgical corridor by gently lying against brain, opening the other side of the funnel. Some dissection maneuvers do not allow the microscissors or bipolar forceps to double as retractors, but most maneuvers allow the shaft to pivot around the instrument’s tips and generate some retraction pressure. 除了吸引器头端的轻微牵拉力，吸引器管可以作为纤细的牵开器叶片；不是将吸引器管固定在解剖、分离的通道壁上，而是轻轻的抬起脑组织以便打开像管道一样的手术通道。吸引器头端的位置并不受吸引器管移动的影响。像吸引器头端的牵拉一样，吸引器管的牵拉力可以随着分离的需要进行调整。优势手的显微剪刀、双极镊也可以作为牵引器用，这些工具的臂同样可以轻轻牵拉脑组织，形成管样手术通道的另一壁。一些解剖操作不允许显微剪刀或双极镊两者均作为牵引器用，但大多数的操作动作允许以手术操作器械的顶端为轴的支点，利用器械的长臂进行轻度的牵拉。 Retraction with Retractors--利用牵开器牵拉 Fixed brain retractors are used very sparingly. A basic Greenberg retractor system has two C-clamps that attach to the Mayfield head holder with their posts pointing toward the vertex and the seated neurosurgeon, and with the C-clamps fixed as close to the surgical field as possible. Clamp posts in this position eliminate the need for extender bars that clutter the working area. The Greenberg retractor is mounted on the posts with the flexible arm arcing up from beneath the surgical field in a gentle curve. Greenberg arms that arc down from above the field often interfere with the hands and can be bumped. Retractor blades that are rounded across their width have a more gentle pressure profile against the brain. The blade length from tip to shoulder is minimized to lower clearance above the brain. The brain is irrigated and covered with Telfa strips to keep the blades from directly touching brain. 脑固定牵开器很少使用。有两个C形叶片的牵开系统固定在Mayfield头架上，固定叶片的底座指向顶部或者坐着的神经外科医生，C形叶片尽可能接近手术操作区域进行固定。这些叶片支撑牵开后避免了其它多余的牵开设备。牵开器安装在柔性的蛇形臂上。牵开器叶片从术区上方弧形向下，有可能会干扰术者的手。牵开器叶片的横径弯曲成弧形以便使压力均匀分布，减轻对脑部的压力。从尖端到肩部的叶片长度尽量最小化以减少牵开器与脑表的间隙。大脑表面覆盖脑棉，防止叶片直接接触大脑。 Retractors should “hold” brain tissue that has already been thoroughly dissected. Extensive preliminary dissection minimizes any “pull” on brain tissue. Maneuvers that slacken the brain also minimize retraction pressure, like evacuating cisternal cerebrospinal fluid (CSF), fenestrating the lamina terminalis, opening the membrane of Liliequist to communicate with posterior fossa cisterns, and lowering external ventricular drains. Lumbar drains are not used during aneurysm surgery because other points of access to CSF are readily available. Mannitol (1 g/kg) is routinely given to dehydrate brain tissue, and Decadron (10 mg) is given to minimize edema from retraction. 牵开器拉力应该足以支撑已经分离开的脑组织。较广范围的初步分离可以将对脑组织的任何“拉动”最小化，能够松弛脑组织的操作同样可减少牵拉的力度，例如排除脑池的脑脊液(CSF)，打开终板，打开Liliequist膜与后颅窝脑池交通，以及降低脑室外引流管。腰大池引流在动脉瘤手术时一般不用，因为通过其它部位引流CSF是现成的。常规给予甘露醇(1克/公斤)将脑组织脱水，地塞米松(10毫克)可以减轻牵拉引起的脑组织水肿。 The tip of the retractor blade does most of the retractor’s work, lifting a lobe or placing arachnoid tissues on stretch. The blade’s width at the tip is narrow for precision, but wide 3 Brain Retraction enough to distribute retraction pressure. The blade’s shoulder gently lays into the brain and opens the working corridor like a funnel. A blade whose shoulder is not angled back will close the mouth of the working corridor and limit maneuverability of the instruments. 牵开器叶片的尖端完成牵开器的大部分工作，抬起脑叶或牵开蛛网膜组织。叶片头端较窄以保证精细，但其宽度又要足以分摊牵拉的力度。叶片的肩部轻柔的拉开大脑并像漏斗一样的打开工作通道。叶片如果没有弯曲状贴合在脑表面（尽量不要悬空），将影响手术通道并限制器械的可操作性。 Mobilizing Brain--推移脑组织 Retractors move brain, but brain prefers not to be moved. Therefore, the amount of retraction is minimized by skullbase approaches that remove bone along the skull base instead. Drilling the sphenoid wing with the pterional approach or the occipital condyle with the far lateral approach widens the surgical corridor under the brain and reduces retraction. Gravity also minimizes retraction. Patient and head position with some approaches will eliminate the need for retractors, like the anterior interhemispheric approach performed with the patient’s head turned laterally 90 degrees and gravity retracting the dependent hemisphere. Similarly, gravity pulls down on the cerebellum during a supracerebellar-infratentorial approach performed with the patient in the sitting position, opening the plane to the pineal region, ambient cistern, and midbrain. Even with more basic approaches like the pterional approach, head extension allows gravity to open the plane between the anterior skull base and inferior frontal lobe, and head rotation vertically aligns the sylvian fissure to allow gravity to pull the frontal and temporal lobes to opposite sides of the fissure. 牵引器移动脑组织，但脑组织有保持原位的张力。因此，颅底的手术入路采用尽量切除颅底骨质的方法减少对脑组织的牵拉。翼点入路磨去蝶骨嵴或远外侧入路磨去枕髁的方法可以扩大手术视野，减少牵拉。重力作用同样可以减少牵拉。一些手术入路体位和头位的摆放同样可以减少牵拉，例如额部半球间入路将患者的头部旋转90度，利用重力作用牵拉术区半球。同样，幕下小脑上入路时采用坐位的体位，可以利用重力作用打开手术界面，到松果体区、环池和中脑。即使是基本的翼点入路，头部旋转并利用重力作用打开前颅底和额叶底面之间的界面，并且头部旋转后让大脑侧裂界面垂直地面，以便允许重力作用于额、颞叶并牵拉其向侧裂两侧分离。 An escape hatch must be prepared during the craniotomy for brain that will be mobilized later. For example, retraction of the temporal lobe during the transsylvian-pretemporal approach to the basilar bifurcation requires drilling the temporal squamosal bone inferiorly until it is flush with the middle fossa floor, and posteriorly beyond the zygomatic root. Without this egress, retraction would compress temporal lobe against a ledge of bone. Mobilized brain needs complete freedom from arachnoid adhesions that might resist retraction. For example, arachnoid of the sylvian cistern couples the frontal and temporal lobes and resists frontal retraction; arachnoid of the chiasmatic cistern tethers the frontal lobe and optic nerve and resists frontal retraction; and arachnoid of the crural cistern couples the deep frontal and temporal lobes and resists temporal lobe retraction. Subarachnoid dissection removes this resistance before placing a retractor. 术者在颅骨切开时必须将骨窗打开到足够范围。例如，颞前经侧裂入路处理基底动脉分叉部动脉瘤时因为牵拉颞叶需要，前下方要将颞骨鳞部磨除到中颅窝底部，后部到颧弓根部。如果没有这样的骨窗范围，牵拉颞叶时因为骨质的遮挡会对颞叶形成压迫。游离移动大脑组织需要完全松解蛛网膜粘连，才能够牵拉开脑组织。例如，侧裂蛛网膜对额叶、颞叶的连接作用阻挡了额叶的抬起，连接额叶与视神经的视交叉池蛛网膜阻挡了对于额叶的抬起，大脑脚池侧方连接额叶和颞叶的内侧，阻挡了对颞叶的牵拉。解剖、松解蛛网膜下腔会在置入牵开器前去除对于牵拉的阻力。 Small arteries can also resist retraction. The anterior temporal artery (ATA) can adhere to the temporal lobe; the recurrent artery of Heubner can adhere to the inferior frontal lobe; and the posterior inferior cerebellar artery (PICA) can adhere to the cerebellar tonsil. Failure to release these adhesions can injure or avulse the artery during retraction. Arteries should not be placed behind a retractor blade because they can be occluded by retraction pressure; they should remain in full view and the dissection should progress around them. Retraction can injure bridging veins, particularly those at the temporal pole, tentorium, and interhemispheric fissure. Bridging veins are preserved whenever possible, but aneurysm exposure can sometimes require their sacrifice. Some veins are sacred because they have scant collateral connections and their sacrifice can cause venous infarctions, including veins along the middle third of the superior sagittal sinus (SSS) and the vein of Labbé. Other veins can be taken because of their extensive collateral connections, including the temporal polar vein bridging to sphenoparietal or cavernous sinus, and superior cerebellar and vermian veins bridging to tentorial sinuses. Failure to sacrifice a bridging vein can result in its avulsion with retraction, which can cause brisk bleeding from a venous sinus and be difficult to control. When a vein must be divided, it should be interrupted only at one point to preserve its retrograde connections to collateral veins. Arachnoid granulations also resist retraction. Granulations along the dura of the middle cranial fossa floor and along the SSS can be avulsed with retraction of the temporal pole and medial frontal lobe, respectively. It is easier to release these adhesions before retracting than to chase venous bleeding after retracting. 小动脉同样影响牵拉。颞前动脉(ATA)常与颞叶有粘连；回返动脉也有可能与额叶底面粘连；小脑后下动脉可能与小脑扁桃体粘连。如果粘连不松解则在牵拉时可能造成动脉的损伤或撕脱。动脉不应该压在牵开器叶片下方，因为这样可能造成动脉梗塞。动脉应该完整的显露在视野中，便于解剖、分离操作在动脉周围进行。牵拉可以损伤桥静脉，尤其是那些在颞极、小脑幕、纵裂等间隙的桥静脉。桥静脉要尽可能地保留，但是显露动脉瘤有时需要牺牲这些静脉。一些引流静脉十分重要，因为它们没有足够的代偿机制，损伤后会导致静脉梗塞，其中包括上矢状窦(SSS)的中三分之一段和拉贝静脉。其它一些有广泛代偿的静脉，包括桥接蝶顶窦或海绵窦的颞极静脉，桥接直窦的小脑上静脉和小脑蚓静脉。未切断桥接静脉可能导致牵拉时的静脉撕裂，从而导致静脉窦难以控制的出血。当静脉必须切断时，它应该在近心端切断，保留其逆行到代偿静脉的部分。蛛网膜颗粒影响牵拉，连接中颅窝底硬脑膜的蛛网膜颗粒以及连接上矢状窦的蛛网膜颗粒影响颞极和额叶内侧面的牵拉。牵拉出血后寻找出血点比牵拉之前松解粘连要麻烦的多。 Most importantly, retraction can avulse an aneurysm’s dome. Aneurysms with intraparenchymal hemorrhage often adhere to that portion of brain. Other aneurysms have notorious points of attachment: a superiorly projecting ophthalmic artery aneurysm adheres to the frontal lobe; an inferiorly projecting anterior communicating artery (ACoA) aneurysm adheres to the optic nerve or chiasm; and a laterally projecting posterior communicating artery (PCoA) aneurysm adheres to the temporal lobe. Retraction early in the dissection of these aneurysms can precipitate intraoperative rupture before establishing proximal control or identifying the aneurysm. These specific retraction moves are avoided with their respective aneurysms. In general, the safest retraction with a ruptured aneurysm is a retraction that is avoided completely. 最重要的是，牵拉可能撕裂动脉瘤顶。伴有脑内血肿的动脉瘤顶部经常与脑组织粘连。有些动脉瘤有极其危险的部位：向上指向的眼动脉动脉瘤和额叶粘连；向下指向的前交通动脉 (ACoA) 动脉瘤和视神经或视交叉粘连；向侧方指向的后交通动脉(PCoA)动脉瘤和颞叶粘连。分离早期尚未近端控制或清晰显露之前，过早的牵拉可以造成动脉瘤的术中破裂。不同的动脉瘤需要避免各自不同的牵拉方向。一般来说，破裂动脉瘤最安全的牵拉是完全避免牵拉。 编译者：九江市第一人民医院，神经外科，胡炜，主任医师，医学博士。 终审：河南省人民医院，神经外科，张长远。 |
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