本期为Worldneurosurgery定期连载的《动脉瘤大师级神作--Seven Aneurysms》著作第十期。本期主要内容为 翼点入路，《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.临时夹闭；6.永久夹闭；7.夹闭后的检查；8.必要的脑切除；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】往期回顾
第六期：动脉瘤手术基本功--永久夹闭
第七期：动脉瘤手术基本功--夹闭后的检查
第八期：动脉瘤手术基本功--必要的脑切除
第九期：动脉瘤手术基本功--术中破裂
第十期：Pterional Approach--翼点入路
■ Position--体位
The patient is positioned supine with a bolster under the shoulder ipsilateral to the aneurysm. The head is rotated 15 to 20 degrees away from the side of the aneurysm. The head is extended approximately 20 degrees, allowing gravity to retract the frontal lobe away from the anterior cranial fossa floor and making malar eminence the high point in the surgical field. The head is then lifted above the level of the heart, out of a dependent position. The neck is maintained in a neutral position, avoiding lateral flexion that might close the angle between the shoulder and head, and
take away valuable working space. This head position aligns the plane of sylvian fissure vertically, allowing frontal and temporal lobes to fall away naturally to either side as the fissure is split later, like pages in a book that rests on its binding. Retractors become unnecessary during the sylvian fissure dissection. This head position and some lateral rotation of the operating table will adjust for most variability in the plane of the sylvian fissure. A conventional head position with 30 degrees of lateral rotation often leaves the temporal lobe overlying the sylvian fissure and closes the plane, even with full table rotation toward the side of the aneurysm.
病人平卧位动脉瘤同侧肩下垫长枕。头部向动脉瘤对侧旋转15到20度，后仰约20度，使颧骨隆突位于手术区域的最高处，以便利用重力作用牵拉额叶离开前颅底。然后头抬高使其高于心脏水平，被动体位。 颈部保持中立位，避免侧方弯曲以免缩小肩和头之间的角度，并影响宝贵的操作空间。头位摆放后让大脑侧裂面垂直于地面，以便随着侧裂的两侧分离后，额叶和颞叶像装订后的书页一样自然分开。这样，大脑侧裂的解剖不必使用牵引器。头位和手术床的左右旋转可以将侧裂的操作平面进行最大程度的调整。传统的头位摆放是横向旋转30度，通常会使颞叶覆盖大脑侧裂并关闭分离界面，即使手术床向动脉瘤一侧充分旋转也不一定能够纠正。
■ Incision--切口
A curvilinear skin incision begins at the zygomatic arch 1 cmanterior to the tragus and arcs to the midline, just behind the hairline at thewidow’s peak (Fig. 10.1A). These two endpoints define the linear fold of thescalp flap, which barely crosses the pterion. Therefore, additional inferior retractionof the scalp flap with “fish hooks” on a Leyla bar (Aesculap; San Francisco, CA)is needed to expose pterion thoroughly. A semicircular incision maximizes the scalpflap. An incision placed too anteriorly along the hairline, having a J- ratherthan a C-shape, results in a smaller craniotomy because the bone flap conformsto the scalp flap. A foreshortened craniotomy might limit exposure of theposterior sylvian fissure or mobilization of temporal lobe.
起自耳屏前1厘米、平颧弓向中线的弧形皮肤切口，止于发际线前缘中点 (图10.1)。头皮切口起/止点之间皮瓣的线性褶皱刚好经过翼点。因此, 需要用“鱼钩”将头皮皮瓣向下稍作牵拉(蛇牌，旧金山,CA)以彻底显露翼点。半圆形的切口可以最大化头皮皮瓣面积。如果太靠前沿着发际线位置设计切口，形成一个J 形而不是C 形皮肤切口，结果会造成骨窗偏小，这是因为骨瓣的大小受限于头皮皮瓣的大小，而颅骨切开骨窗的减小可能会影响大脑侧裂的显露及颞叶的牵开。
■ Extracranial Dissection--颅外切开
The scalp is elevated only enough to expose thezygomatic root posterior-inferiorly and the keyhole anteriorly. The superficialfat overlying the temporalis fascia should not be entered because the frontalisbranch of the facial nerve lies in this tissue plane and can be injured withadditional elevation of the scalp flap. The temporalis muscle is incised from thezygomatic arch to the superior temporal line along the skin incision, thenanteriorly to the keyhole, running 1 cm below the superior temporal line. The temporalis is flapped anteriorly,leaving a cuff of fascia and muscle along the superior temporal line to suturethe muscle to during closure. The fish hooks are repositioned to retract thetemporalis muscle as well as the scalp flap.
头皮切开程度要求皮瓣翻开后可以显露后下方的颧弓根部以及前部的关键孔。避免切开分离覆盖在颞肌筋膜表面的脂肪，这是由于面神经额支走行在这个平面，并且皮瓣过度的牵拉可以损伤此神经。沿着皮肤切口从颧弓到颞上线切开颞肌，然后在颞上线下方1CM切到前面的关键孔。颞肌翻向前方，在颞上线上保留一条颞肌筋膜以便关闭切口时缝合肌肉。重新调整鱼钩位置以便牵拉颞肌以及皮瓣。
Patients with largefrontal sinuses that will be violated by the craniotomy will require avascularized pericranial graft for the repair during closure. Head computed tomography (CT) scans or scoutfilms from the angiogram demonstrate the frontal sinus size. It iseasier to harvest this pericranial flap during the opening than later duringthe closure. The depth of the skinincision stops short of the cranium to preserve pericranium, going only throughgalea and deep connective tissue. The scalp flap is elevated away from thepericranium, opening a white, avascular tissue plane sharply with upwardtraction on the scalp. The pericranium can be incised well behind the skinincision, extending posteriorly and across midline to enlarge the flap’s size,if necessary. Pericranial flaps elevate cleanly from the bone with blunt dissectionand can be preserved during the procedure in moist sponges. Cerebrospinal fluid (CSF) leaks through the frontalsinus are unwanted complications that may require repeat craniotomy, directrepair, and sometimes ventriculo-peritoneal shunting. It is far better toprevent this complication than to have to deal with it later when tissues are scarredand the pericranium is compromised.
额窦发达的患者在开颅时需要预留带蒂骨膜瓣以便关颅时修补额窦。头部断层扫描(CT)扫描或血管造影的定位片可以显示额窦的大小。开颅时比关颅时更容易剥离颅骨骨膜瓣备用。皮肤切口的深部做到只切开帽状腱膜及深部结缔组织，保留颅骨膜。向上牵拉头皮并沿白色/无血管的组织间隙锐性分离头皮和颅骨膜，从而将头皮皮瓣从骨膜上分离，在皮瓣掀开后可以较好的切开骨膜，如果有必要可以向后向中线扩大骨膜瓣，骨膜瓣较容易从颅骨钝性剥离，并在手术过程中保护在潮湿的纱布中。 额窦的脑脊液(CSF)漏是大家不希望发生的并发症，可能需要再次开颅/ 直接修补/ 有时需要脑室-腹腔分流。针对这种并发症，最好的是预防，而不是发生并发症且脑组织及骨膜破坏后再事后处理。
■ Craniotomy--开颅
A frontotemporal craniotomy is made using a single temporal bur hole (Fig. 10.1B). The craniotomy follows the temporalis incision posteriorly, then curves anteromedially to the foramen of the supraorbital nerve and inferiorly to the floor of the anterior cranial fossa. This spot is often covered by the fold in the scalp flap, which requires additional retraction during the craniotomy. This seemingly small corner of bone, if it remains, can narrow the outer opening of the operative corridor and limit the maneuverability of instruments held on this side.
额颞颅骨切开首先在颞部(图10.1 b)钻孔，然后沿着颞肌切口铣开颅骨，再弯向前内侧的眶上神经孔然后向下到前颅底。这个颞部的骨孔常被皮瓣的褶皱覆盖, 这里钻孔/开颅需要进一步牵拉头皮。这个看似位于边缘的颅骨如果开颅时未切除，则会阻挡手术时的操作通道/限制此侧手术器械的操作灵活性。
Duralpreservation is particularly important along the inferior bone cut, which iswhere dura is thinnest. The frontal lobe behind this dura is retracted whenpterion is drilled, and tears in this dura can expose brain, leading to injury,swelling, and contusions. Dural integrity is checked by irrigating through thebony cut and shining light directly down on the dura. If there is anysuggestion of a dural tear, an additional bur hole can be made at the keyhole,and the dura can be dissected from the inner table of skull. Dural tears are avoidedby not crossing pterion with the drill, instead following the floor of thefrontal fossa posteriorly. If this dura is torn, intact dura over the orbitalroof deep to the tear is elevated and the tear is either repaired primarilywith suture or covered with Telfa to protect exposed brain.
沿着骨窗下缘切开时硬脑膜的保护尤为重要，因为这里的硬脑膜最薄。在磨除翼点时需要牵开额叶的硬脑膜，如果此处硬脑膜是撕开的，则大脑被暴露、导致损伤、肿胀、挫伤。硬脑膜完整性的检查通过在颅骨切开的骨缝直接向硬脑膜冲水，可见水花反光。如果有任何硬脑膜撕裂的情况，可以在关键孔钻开另一骨孔，将内板下方的硬脑膜游离。在铣开前额窝颅骨之后，避免用铣刀打开翼点骨质可以避免硬脑膜的撕裂。如果此处硬脑膜撕裂，抬起完整的眶顶硬脑膜直到深部撕裂处，可以用缝合修复撕裂处或覆盖Telfa保护露出的脑组织。
■ Drilling the Pterion--磨开翼点
The pterion is located at the intersectionof the frontal bone, the parietal bone, and the greater wing of the sphenoidbone. Pterion lies at the point where the coronal suture intersects with thegreater wing, providing an identifiable landmark. Although this point lies onthe flat outer table of bone externally, internally the lesser wing of thesphenoid joins the inner table of bone here and is continuous with the orbital surfaceof the frontal bone, or orbital roof. The inner surface of pterion is a complexthree-dimensional structure that prevents its crossing with the foot plate of adrill, and instead requires that it be snapped or cracked to remove the boneflap.
翼点位于额骨、顶骨、蝶骨大翼的交汇点。冠状缝在翼点处和蝶骨大翼相交汇。提供了一个可供辨识的标志。虽然从外面看，此点位于平坦的外板上，但是在内侧面此点的内板出现蝶骨小翼，并进向内形成额骨眶面以及眶顶壁。因此，翼点的内侧面是一个立体的三维结构，不适宜铣刀脚板通过，而是咬开或者通过抬起骨板而掰断。
The drill is used to remove pterion and the lesser wing of the sphenoid medially to the superior orbital fissure (SOF), with the goal of making a flat surface over the orbit connecting the anterior and middle cranial fossae (Fig. 10.1C). The orbital plate of the frontal bone has ridges and irregularities that mirror the sulci and gyri of inferior frontal lobe. The frontal sinus lies between the inner and outer tables of frontal bone and can extend laterally to the craniotomy cut. Although the frontal sinus should not be entered if possible, the craniotomy and overall exposure should not be compromised by its avoidance either.
磨钻用来磨除翼点以及蝶骨小翼向内侧到眶上裂（SOF），目的是为了获得连接前颅窝中颅窝的眼眶后上方的光滑平面(Fig. 10.1C)。额骨眶板表面不平整并对应着额叶底面的沟回。额窦位于额骨内外板之间并可以扩展到侧方的颅骨切开处，虽然，开颅时应该尽量不打开额窦，不过开颅以及全部的显露过程不必受到额窦的影响。
The lesser wing of the sphenoid bone is flattened until the lateral edge of the SOF is reached. The bone opens like a Gothic arch to transmit a fold ofdura containing the oculomotor, trochlear, and abducens nerves, as wellas the superior ophthalmic vein and ophthalmic nerve. With most aneurysms,skeletonization of the dural fold of the SOF is sufficient to flatten thepterion. With some patients, the lesser wing of the sphenoid bone and the base of the anterior clinoid process create aprominent bony hump that can obscure the view into the carotid cisternsintradurally. These structures can bedrilled down or rongeured past the lateral extent of the SOF, along the duralfold. The dural fold can be mobilized laterally by removing bone that forms thelateral or temporal border of the SOF, opening into the lateral orbit. Onceremoved, the dural fold mobilizes laterally and the baseof the clinoid can be rongeured. This deep bone is often a conduit foremissary veins, and bleeding is controlled with bone wax.
磨除蝶骨小翼直到SOF的外侧边缘。骨质磨除后留下像哥特式拱门一样的硬脑膜返折，其内包含动眼、滑车、外展神经以及上部眼静脉和视神经。对于大多数动脉瘤来说，骨质磨除到眶上裂硬脑膜返折处足以使术区平坦。部分病人，蝶骨小翼以及前床突的基底形成一个明显的骨性隆起，可以阻挡硬膜下到颈动脉池的视线。这些结构可以沿着硬脑膜返折向内磨除或用咬骨钳咬过SOF外侧缘。通过磨除形成SOF外侧或颞界的骨质，到眼眶外侧壁后，一旦磨除这些骨质，硬脑膜返折可以向侧方推移，咬骨钳即可咬除床突基底部。这些深部骨质常是导静脉的导管，可以用骨蜡控制出血。
The squamosal portion of the temporal bone is drilled inferiorly to the middle fossa floor. The endpoint for removal of bone from the skull base is a flat surface upon which to reflect the dural flap.
向下磨除颞骨鳞部到中颅窝底。颅底骨质磨除的终点标志是一个平面的反映了硬脑膜瓣。
■ Dural Opening--打开硬膜
The dura is opened with a semicircularincision, extending from the floor of the middle cranial fossa at theposteriorinferior aspect of the exposure to the floor of the anterior cranialfossa at the anterior-inferior aspect of the exposure. Multiple stay suturesflatten the dural flap. The hinge point is the anterior clinoid process, sothis point requires adequate bony reduction extradurally. Thorough resection ofthe pterion opens an unobstructed view along the dural flap into the carotidcistern (Fig. 10.1D).
半圆形切口打开硬脑膜，显露从硬膜后下方的中颅窝底到硬膜前下方的前颅窝底。多针缝合线牵拉硬膜使硬脑膜瓣平坦。关键点是前床突，此点需要足够的硬膜外骨质磨除。彻底切除翼区就可以沿着硬膜瓣到颈动脉池打开一个畅通无阻的视路 (图10.1 d)。
Fig.10.1 (A) Head position, skin incision, and craniotomy for the pterionalcraniotomy (right side). The superficial temporal artery is preserved posteriorto the incision in case it is needed for a bypass. Superficial fat overlyingthe temporalis fascia is not entered because the frontalis branch of the facialnerve lies in this tissue plane. (B) A craniotomy flap for the pterional approach.Dural preservation is particularly important inferiorly where the dura isthinnest and where the pterion is drilled. Dural tears are avoided by notcrossing the pterion with the drill. Instead, bone is cut on either side of thepterion and cracked by elevating the bone flap. (C) Drilling the pterion. Removing thepterion and lesser wing of the sphenoid medially to the superior orbitalfissure (inset) flattens the surface over the orbit connecting the anterior andmiddle cranial fossae. (D) Final exposure of the pterional approach. Thoroughresection of the pterion opens an unobstructed view along the dural flap intothe carotid cistern. Multiple tacking sutures placed deeply on the dural flappull it snugly against the pterion.
Fig. 10.1 （A）头位，切口，翼点入路开颅（右侧）。颞浅动脉保留于切口后方，以备血管搭桥需要。避免进入颞肌筋膜表面的浅层脂肪，因为面神经额支行走于该层组织内。（B）翼点入路开颅的骨瓣。下方的硬膜保护尤其重要，因为此处的硬膜最薄。为了避免硬膜破损，开颅时翼点不用铣刀打开。颅骨应从翼点的两侧铣开，然后撬开骨瓣。（C）翼区的磨除。去除翼点和眶上裂内侧的蝶骨小翼，磨平连接前颅窝中颅窝的眼眶后上方平面。（D）翼点入路的最后显露。彻底切除翼区就可以沿着硬膜瓣到颈动脉池打开一个畅通无阻的视路。多针缝合线牵拉硬膜使硬脑膜瓣平坦。
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