劉寧 閆長祥 (首都醫(yī)科大學(xué)三博腦科醫(yī)院神經(jīng)外科，北京 100093)

巖斜區(qū)腦膜瘤術(shù)中外展神經(jīng)的保護

劉寧 閆長祥*
(首都醫(yī)科大學(xué)三博腦科醫(yī)院神經(jīng)外科，北京 100093)

目的總結(jié)30例巖斜區(qū)腦膜瘤手術(shù)患者的臨床資料，以期提高巖斜區(qū)腦膜瘤的切除程度，并降低外展神經(jīng)的損傷。方法總結(jié)30例巖斜腦膜瘤的臨床特點、手術(shù)經(jīng)驗及外展神經(jīng)受損情況，探討Dorello's管區(qū)病理解剖特點與巖斜區(qū)腦膜瘤的關(guān)系。結(jié)果30例巖斜區(qū)腦膜瘤，<2.5 cm者6例，2.5～3.5 cm者16例，>3.5 cm者8例。術(shù)后出現(xiàn)外展神經(jīng)功能障礙者<2.5 cm者0例，2.5～3.5 cm者5例，>3.5 cm者4例。暫時性外展神經(jīng)功能障礙者7例，永久性障礙者2例。結(jié)論巖斜區(qū)腦膜瘤術(shù)中外展神經(jīng)出腦干端、穿巖斜硬腦膜端容易受損傷。提高對Dorello's區(qū)解剖認(rèn)識、腫瘤的早期發(fā)現(xiàn)、良好的腫瘤暴露、神經(jīng)粘連處的銳性分離等，有助于切除腫瘤并減少外展神經(jīng)的醫(yī)源性損傷。

巖斜腦膜瘤; Dorello's管; 外展神經(jīng)

Dorello's管為外展神經(jīng)穿斜坡硬腦膜處至其穿蝶巖韌帶(Gruber's韌帶)下方的纖維管道，其內(nèi)走行外展神經(jīng)。Dorello's管是顱底外科的重要結(jié)構(gòu)，該區(qū)域位置深在、周圍解剖關(guān)系復(fù)雜，許多顱底腫瘤尤其是巖斜區(qū)腦膜瘤的手術(shù)治療都會涉及到該區(qū)域[1～3]。我們總結(jié)30例巖斜腦膜瘤手術(shù)患者的臨床資料，分析外展神經(jīng)易損傷的因素，以期深化理解該區(qū)域解剖特點，提高巖斜區(qū)腦膜瘤的切除程度并降低外展神經(jīng)的損傷機率。

對象與方法

一、一般資料

30例巖斜區(qū)腦膜瘤，男性12例，女性18例。平均年齡42.5歲。

二、臨床表現(xiàn)

頭痛15例，肢體運動障礙8例，顏面部感覺障礙6例，共濟運動障礙8例，眼球運動障礙4例，聲音嘶啞1例。

三、影像學(xué)檢查

30例腫瘤 CT上多呈等或稍高密度；MRI多呈等或稍長T1信號、等長T2信號，邊界清楚，多呈類圓形，打藥后病灶多呈均勻明顯強化(圖1,3)。腫瘤體積：<2.5 cm者6例，2.5～3.5 cm者16例，>3.5 cm者8例。

四、手術(shù)治療

手術(shù)路徑：顳下入路14例，乙狀竇前入路7例，顳下聯(lián)合乙狀竇后入路6例，乙狀竇后入路3例。術(shù)中所見：巖斜腦膜瘤多呈膨脹性生長，術(shù)中發(fā)現(xiàn)其基底多位于鞍背、后床突、海綿竇后壁、巖尖等處硬腦膜且與之粘連緊密。腫瘤多呈灰黃色、黃白色，質(zhì)地通常硬韌，質(zhì)地柔軟者很少，血供通常非常豐富。體積較小者一般與周圍神經(jīng)、血管、腦干等粘連較輕，隨著病灶體積增大，粘連亦隨之加重。動眼神經(jīng)通常位于腫瘤頂部，三叉神經(jīng)位于外側(cè)略上方，外展神經(jīng)通常位于腫瘤腹側(cè)底面，經(jīng)常需將腫瘤全部切除后才能顯露該神經(jīng)全貌(圖2)。體積較大腫瘤一般將腦池段外展神經(jīng)向?qū)?cè)推擠、粘連顯著并侵及Dorello's管外口(圖4)。

結(jié) 果

全切21例(70%)，近全切8例(27%)，大部切除1例(3%)，病理檢查為纖維型腦膜瘤(圖5)。術(shù)后外展神經(jīng)功能障礙：<2.5 cm者0例，2.5～3.5 cm者5例，>3.5 cm者4例。暫時性外展神經(jīng)功能障礙者7例(3個月至半年得以恢復(fù))，永久性障礙者2例(超過1年未好轉(zhuǎn))。術(shù)后無1例死亡患者，暫時性氣管切開1例，30例患者均有隨訪，隨訪3年11個月，平均隨訪2年3個月，無一例復(fù)發(fā)，顏面部感覺障礙者8例，面癱者4例，輕度偏癱者3例，動眼神經(jīng)障礙者2例。

圖1 術(shù)前MRI軸位增強掃描

Fig 1 Pre-operative axial view of contrast MRI

The arrow showed that the tumor was located on the left side of the petrous apex and the upper clivus, with a diameter of 2.0 cm, even texture, clear boundary and medium blood supply. The brain stem was slightly compressed.

圖2 行左側(cè)枕下乙狀竇后入路腫瘤全部切除后的術(shù)中影像

Fig 2 Intra-operative image after tumor total removal via left post-sigmoid sinus approach

Abducent nerve was beneath the base of the tumor.

圖3 術(shù)前MRI軸位增強掃描

Fig 3 Pre-operative axial view of contrast MRI

The arrow showed that the tumor was large in size with a diameter of about 4.5 cm, uniform texture, clear boundary and abundant blood supply. The tumor base was wide and invaded the whole slope. The brainstem and basilar arteries were significantly compressed and deformed, shifted toward the contralateral side.

圖4 行右側(cè)顳下入路腫瘤全部切除后術(shù)中影像

Fig 4 Intra-operative image after tumor total removal via right sub-temporal approach

The tumor invaded the bilateral Dorello's cannal where the abducent nerve pierced the clival dura. The basilar artery was significantly shifted to the contralateral side.

圖5 術(shù)后病理圖片(HE, ×400)

Fig 5 Post-operative pathological image(HE, ×400)

Fibrous meningioma with scattered calcification (WHO I grade). Nuclear had less atypia, mostly was ovoid or fusiform, and arranged loosely. A large number of glial fibrillary components arranged around the tumor cells.

討 論

我們將外展神經(jīng)分為腦池段、Dorello's管段、海綿竇段、眶上裂段及眶內(nèi)段。Dorello's管為介于巖尖和上斜坡外側(cè)緣之間的橢圓形骨纖維性管道，內(nèi)含靜脈性血竇，其內(nèi)穿行外展神經(jīng)。Dorello's管上壁為蝶巖韌帶，該韌帶的重要作用是固定并保護外展神經(jīng)[4～7]。巖斜腦膜瘤體積較大時，尤其是>3.5 cm者，可將Dorello's管內(nèi)外展神經(jīng)移位，蝶巖韌帶的切割力會損傷外展神經(jīng)，術(shù)前患者即可表現(xiàn)外展受限。腦池段外展神經(jīng)的外層鞘膜通常與蝶巖韌帶、巖尖處的硬腦膜緊密粘連。在電灼切斷巖斜區(qū)硬腦膜腫瘤基底時如電灼海綿竇后壁內(nèi)側(cè)三角硬腦膜時，熱損傷可能會傷及該段外展神經(jīng)，適度的電灼且電灼過程不斷滴水降溫有助于外展神經(jīng)的保護。巖斜區(qū)腦膜瘤通常呈膨脹型生長，朝對側(cè)方向推擠腦池段外展神經(jīng)，該段神經(jīng)活動度較大，且腫瘤與神經(jīng)之間通常有雙層蛛網(wǎng)膜結(jié)構(gòu)，腫瘤體積不是特別巨大時，通常較易分離。

結(jié)合臨床經(jīng)驗，我們認(rèn)為腫瘤直徑<2.5 cm的巖斜腦膜瘤(圖1,2)，外展神經(jīng)多可不被侵及，術(shù)后很少發(fā)生眼球外展受限；腫瘤直徑處于2.5～3.5 cm，腫瘤通常推擠腦池段外展神經(jīng)并有不同程度的粘連，術(shù)后可能會有一定程度神經(jīng)功能障礙；而當(dāng)腫瘤直徑大于3.5 cm時(圖3,4,5)，腫瘤會進一步侵及并環(huán)形包繞穿斜坡硬腦膜處的外展神經(jīng)，術(shù)后較易發(fā)生其功能障礙。后床突下方(19.2±2.6)mm為外展神經(jīng)穿斜坡硬腦膜處，外展神經(jīng)出橋延溝處及穿斜坡硬腦膜處位置恒定，術(shù)中較易損傷，電灼外展神經(jīng)穿斜坡硬腦膜周圍腫瘤基底時要格外小心。

根據(jù)腫瘤的生長特點，結(jié)合術(shù)者的手術(shù)經(jīng)驗，選擇合適的手術(shù)入路暴露腫瘤，術(shù)中腫瘤與外展神經(jīng)粘連處盡可能多的銳性分離，有助于降低神經(jīng)損傷。巖斜腦膜瘤通常向周圍推擠顱神經(jīng)，外展神經(jīng)通常位于腫瘤底面內(nèi)側(cè)深部，腦池段多有不同程度移位，故不管是幕上入路還是幕下入路，通常需將腫瘤全部切除后方可顯露其全貌。故在全切腫瘤前提前判斷Dorello's管、外展神經(jīng)的位置是非常重要的[8～10]。我們手術(shù)經(jīng)驗認(rèn)為，顳下入路暴露過程中，弓狀隆起、三叉神經(jīng)穿Meckle's孔處、后床突及鞍背是固定結(jié)構(gòu)，而經(jīng)巖骨后方暴露腫瘤過程中內(nèi)耳門、頸靜脈孔等是固定結(jié)構(gòu)，通過這些結(jié)構(gòu)可預(yù)先判斷外展神經(jīng)穿斜坡硬腦膜位置、Dorello's管等。病理解剖中，Dorello's管及蝶巖韌帶上方為受壓位置上抬的動眼神經(jīng)、后交通動脈，蝶巖韌帶外側(cè)端緊鄰受壓朝側(cè)方移位的三叉神經(jīng)腦池段。術(shù)中分塊切除腫瘤，有條件時用超聲吸引器，瘤內(nèi)減壓減少腫瘤體積有助于上述神經(jīng)的保護。外展神經(jīng)出腦干端、穿巖斜硬腦膜端(進Dorello's管前)位置固定，這兩處更容易受損，故沿腫瘤內(nèi)側(cè)底面分離時，盡量與斜坡縱軸方向游離，減少橫向方向的分離動作。巖斜腦膜瘤外展神經(jīng)通常向內(nèi)側(cè)橫向移位，外展神經(jīng)在橫軸上的張力是飽滿的，尤其是在其穿斜坡硬腦膜處的橫向操作更易加重其損傷[11～13]。

Dorello's管是顱底外科的重要解剖標(biāo)志，也是定位外展神經(jīng)的標(biāo)志性結(jié)構(gòu)。巖斜區(qū)腦膜瘤經(jīng)常侵及該區(qū)域，術(shù)中外展神經(jīng)出腦干端、穿巖斜硬腦膜端容易受損傷，提高對Dorello's區(qū)解剖認(rèn)識、腫瘤的早期發(fā)現(xiàn)、良好的腫瘤暴露、神經(jīng)粘連處的銳性分離等，有助于切除腫瘤并減少外展神經(jīng)的醫(yī)源性損傷。

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Protectionofabducentnerveintheoperationofpetroclivalmeningioma

LIUNing,YANChangxiang

DepartmentofNeurosurgery,SanboBrainHospital,CapitalMedicalUniversity,Beijing100093, China

ObjectiveThe clinical data of 30 cases of petroclival meningioma have been summarized in order to improve the resection degree of petroclival meningiomas and reduce the abducent nerve injury.MethodsThe clinical characteristics, surgical techniques and abducent nerve damages were discussed and the relationship between the microanatomy of Dorello's cannal and petroclival meningioma was investigated.ResultsIn 30 cases of petroclival meningiomas, tumor diameter <2.5 cm was in 6 cases, 2.5～3.5 cm in 16 cases, and >3.5 cm in 8 cases. After operation for patients with tumor diameter <2.5 cm, no abducent nerve dysfunction occurred; for patients with tumor diameter of 2.5～3.5 cm, there was 5 cases of abducent nerve dysfunction and for tumor diameter >3.5 cm, there were 4 cases. There were 7 cases of temporary dysfunction and 2 cases of permanent injury.ConclusionDuring the operation of petroclival meningioma, abducent nerve is prone to injury in the places where it originates from the pontomedullary sulcus and pierces the petroclival dura. Better knowledge of Dorello's cannal, early diagnosis and good exposure of the tumor, and acute separation in the adhesion will be helpful for the remove of the tumor and reduction of the iatrogenic injury of abducent nerve.

Petroclival meningioma; Dorello's cannal; Abduncent nerve

1671-2897(2016)15-156-03

·論著·

R 739

A

劉寧，主治醫(yī)師，醫(yī)學(xué)碩士，E-mail:liuning301@aliyun.com

*通訊作者： 閆長祥，主任醫(yī)師，醫(yī)學(xué)博士，E-mail: yancx65828@163.com

2015-02-15;

2015-04-10)