脊髓背側(cè)蛛網(wǎng)膜網(wǎng)帶是一種較罕見的疾病,具有特征性的“手術(shù)刀征”,本期文章通過對其病因、病理生理、臨床表現(xiàn)、病理、影像學(xué)特征、鑒別診斷、診治流程、治療及預(yù)后等全面系統(tǒng)的闡述這一疾病。
蛛網(wǎng)膜網(wǎng)帶(Arachnoid webs)是一種位于髓外硬膜下的增厚的橫行束帶狀蛛網(wǎng)膜組織,可延伸至脊髓軟腦膜表面。這種病例較為罕見,最為常見的發(fā)生部位是發(fā)生于中上段胸髓的背側(cè)蛛網(wǎng)膜網(wǎng)帶(dorsal arachnoid web,DAW)。由于蛛網(wǎng)膜網(wǎng)帶的牽拉作用,在影像學(xué)上,造成脊髓背側(cè)局部受壓凹陷和前移位,導(dǎo)致背側(cè)腦脊液間隙增寬,產(chǎn)生一種稱之為“手術(shù)刀征”(scalpel sign)的脊髓特征性影像特征,繼發(fā)神經(jīng)功能障礙,引起局部神經(jīng)組織受壓的癥狀,并可導(dǎo)致腦脊液的液體動力學(xué)改變,比如脊髓空洞(syringomyelia)[4,5,6]。 (一)病因(Etiology)及病理生理(Pathophysiology): 蛛網(wǎng)膜網(wǎng)帶的確切病因尚不清楚。大多數(shù)情況下,沒有明顯的外傷或手術(shù)史。目前絕大多數(shù)文獻報道的以上胸段脊髓背部多見,偶可見發(fā)生于頸髓的病例報道[7]。這提示胸髓蛛網(wǎng)膜網(wǎng)帶可能有共同的病因。為什么好發(fā)于上胸椎的原因目前尚不清楚。有文獻報告背側(cè)位置可能與后隔憩室(diverticulations of the septum posticum)形成蛛網(wǎng)膜囊腫的理論有關(guān),后隔憩室是一層縱向分隔蛛網(wǎng)膜下腔后部的薄膜。蛛網(wǎng)膜網(wǎng)帶可能是不完整蛛網(wǎng)膜囊腫或蛛網(wǎng)膜囊腫形成過程中的中斷。也可以想象,蛛網(wǎng)膜網(wǎng)帶可能實際上是由塌陷的蛛網(wǎng)膜囊腫的壁組成的。
脊髓空洞癥與背側(cè)蛛網(wǎng)膜網(wǎng)帶的存在似乎有關(guān)。從空洞前狀態(tài)發(fā)展到脊髓空洞癥,MRI可能有脊髓信號強度波譜的變化。蛛網(wǎng)膜網(wǎng)帶水平以上或以下形成脊髓空洞癥的決定因素與蛛網(wǎng)膜網(wǎng)帶兩側(cè)的腦脊液壓差有關(guān)。頭部腦脊液壓力增大會導(dǎo)致尾部形成脊髓空洞癥,反之亦然。這與脊髓空洞癥形成的髓內(nèi)脈壓理論有關(guān),在該理論中,蛛網(wǎng)膜下腔梗阻一側(cè)較低的腦脊液壓力通過梯度壓差的虹吸作用,導(dǎo)致脊髓在每次收縮期擴張,導(dǎo)致腦脊液通過血管周圍的小間隙進入脊髓,形成脊髓空洞。電影磁共振成像(Cine MR)能夠分析腦脊液流動動力學(xué),對于評估蛛網(wǎng)膜網(wǎng)帶可能有價值。通過Cine MR可能顯示蛛網(wǎng)膜網(wǎng)帶病例中蛛網(wǎng)膜下腔背側(cè)腦脊液流量的改變。術(shù)前和術(shù)后成像也可以分析蛛網(wǎng)膜網(wǎng)帶松解切除后改善的腦脊液流量。
(二)臨床表現(xiàn)(Clinical presentation): 各種與束帶相關(guān)的癥狀和體征,包括:上下肢無力和感覺癥狀,有時通過平臥緩解;反射亢進、痙攣性截癱、陣攣和張力亢進;背部疼痛;步態(tài)不穩(wěn),行走困難等。 (三)病理(Pathology): 由于脊髓背側(cè)出現(xiàn)蛛網(wǎng)膜增厚束帶,導(dǎo)致脊髓前部局灶性移位,有時會因為改變了腦脊液流動動力學(xué)導(dǎo)致脊髓空洞癥。蛛網(wǎng)膜增厚束帶在蘇木精-伊紅染色顯微攝影顯示纖維膜組織和營養(yǎng)不良微鈣化[8]。
(四)影像學(xué)特征(Imaging features): 常規(guī)影像檢查有時不能直接的顯示蛛網(wǎng)膜網(wǎng)帶,“手術(shù)刀征”似乎是一種重要的二次成像征象,提示蛛網(wǎng)膜網(wǎng)帶的存在。影像診斷的關(guān)鍵特征是胸部脊髓的局灶性背側(cè)凹陷和前移位,最好在MRI上識別(CT脊髓造影(CT myelogram)也可以作為替代)[9]。
MRI:脊髓的局灶性背側(cè)凹陷和前移位,背側(cè)腦脊液間隙的擴大,局部胸髓向前移位,脊髓的腹面沒有變形。矢狀位MRI腦脊液間隙擴大的輪廓與手術(shù)刀的輪廓相似(刀刃指向背側(cè)的手術(shù)刀),被稱為“手術(shù)刀征”??拷刖W(wǎng)膜網(wǎng)帶上方或下方的脊髓可能顯示T2信號增強,這可能會發(fā)展形成為脊髓空洞。
CT脊髓造影:顯示脊髓背側(cè)有特征性的局灶性凹陷,脊髓后腦脊液間隙變寬。
(五)鑒別診斷(Differential diagnosis): 背側(cè)蛛網(wǎng)膜網(wǎng)帶(dorsal arachnoid web,DAW)需要與脊髓背側(cè)蛛網(wǎng)膜囊腫(dorsal spinal arachnoid cyst)及腹側(cè)脊髓疝(ventral cord herniation)鑒別。 1、脊髓背側(cè)蛛網(wǎng)膜囊腫(dorsal spinal arachnoid cyst):蛛網(wǎng)膜囊腫可以通過壁的邊緣、脊髓表面光滑寬闊的扇形結(jié)構(gòu)以及脊髓造影中通常填充速度慢于蛛網(wǎng)膜下腔剩余部分的事實來識別。具體的特征:脊髓平滑扇形,脊髓造影無或延遲混濁。外觀非常相似,但脊髓造影可以顯示囊腫(通常填充對比劑的速度慢于蛛網(wǎng)膜下腔的其余部分);脊髓變形不太明顯,即無手術(shù)刀征;還應(yīng)考慮髓內(nèi)囊腫/異常信號的其他原因,需要進行對比以排除髓內(nèi)腫塊(例如室管膜瘤)。
2、腹側(cè)脊髓疝(ventral cord herniation)/特發(fā)性脊髓疝(idiopathic spinal cord herniation):腹側(cè)疝點的局部脊髓表面變形并脊髓前硬膜缺損突出是其典型的特征。通??梢詮某R?guī)影像學(xué)上與蛛網(wǎng)膜囊腫或蛛網(wǎng)膜網(wǎng)帶區(qū)別開來,在脊髓疝中,脊髓組織從腹側(cè)硬膜缺損處突出,常表現(xiàn)為沿脊髓腹側(cè)的局部畸形。然而,當(dāng)腹側(cè)脊髓與前硬膜緊密相對時,可能很難或不可能區(qū)分背側(cè)蛛網(wǎng)膜網(wǎng)帶和前脊髓疝。
在唯脊柱公眾號放映廳上,椎管內(nèi)腫瘤的影像學(xué)診斷(三)的視頻講解時,來自紐約大學(xué)朗格尼醫(yī)學(xué)中心的神經(jīng)放射科主任Dr. Fatterpekar在詳細的介紹了髓外硬膜下占位的蛛網(wǎng)膜囊腫(Spinal arachnoid cyst)需要與特發(fā)性脊髓疝(idiopathic spinal cord herniation/ Ventral cord herniation)和胸髓背側(cè)蛛網(wǎng)膜網(wǎng)帶(Dorsal thoracic arachnoid web)鑒別。胸髓背側(cè)蛛網(wǎng)膜網(wǎng)帶其主要特征是“手術(shù)刀征”。注意這里類似手術(shù)刀樣的尖銳成角,有時還伴有水腫。經(jīng)過手術(shù)松解,脊髓形態(tài)恢復(fù)正常,水腫消失。如果要區(qū)分這三者,注意觀察是否存在膜狀結(jié)構(gòu)。如果進行脊髓造影,有充盈缺損提示診斷為蛛網(wǎng)膜囊腫。如果脊髓有輕微的腹側(cè)成角,沒有見到膜狀結(jié)構(gòu),診斷為特發(fā)性脊髓疝。而如果可見手術(shù)刀樣的尖銳成角,則診斷為蛛網(wǎng)膜網(wǎng)帶。(有興趣的老師可以在如下鏈接觀看:https://mp.weixin.qq.com/s/fUKHjYOOlQ-iiwLJvanj6g)
(六)診治流程(Flow diagram for diagnostic and therapeutic approach):
(七)治療和預(yù)后(Treatment and prognosis): 根據(jù)上述流程圖的評估,較嚴(yán)重的需要進行外科治療,神經(jīng)外科手術(shù)切除束帶及時阻斷了病情進展,一般都可以治愈,,病人預(yù)后較好[10]。 手術(shù)治療: 1、顯微鏡鏡下開放手術(shù)[11-21]:
2、胸髓蛛網(wǎng)膜網(wǎng)帶微創(chuàng)切除術(shù)(Minimally Invasive Excision of Thoracic Arachnoid Web)[12] 總結(jié): 放射科、神經(jīng)外科、脊柱外科、神經(jīng)科等科室的醫(yī)生應(yīng)該及時準(zhǔn)確的識別“手術(shù)刀征”,診斷蛛網(wǎng)膜網(wǎng)帶。如未能識別這種影像學(xué)征象可能導(dǎo)致治療延遲和脊髓功能惡化。如果術(shù)前未考慮診斷蛛網(wǎng)膜網(wǎng)帶,而僅對脊髓空洞進行分流術(shù)甚至蛛網(wǎng)膜網(wǎng)帶活檢,這可能會導(dǎo)致作為主要原因的異常的束帶得不到準(zhǔn)確的治療。“手術(shù)刀征”提示存在蛛網(wǎng)膜背側(cè)網(wǎng)帶,應(yīng)及時進行會診評估手術(shù),以確定是否需切除蛛網(wǎng)膜網(wǎng)帶或脊髓空洞分流術(shù),這對患者的病情進展及預(yù)后至關(guān)重要[23]。 題外知識:蛛網(wǎng)膜網(wǎng)帶引起阻塞性腦積水[24]
參考文獻: 1.. A.Prof Frank Gaillard et al. Article: Dorsal thoracic arachnoid web. Radiopaedia.org. 2. Matt Skalski. Case: Dorsal thoracic arachnoid web. Radiopaedia.org. 3. Christine Goh. Case: Dorsal arachnoid web: scalpel sign. Radiopaedia.org 4. Reardon MA, Raghavan P, Carpenter-Bailey K, Mukherjee S, Smith JS, Matsumoto JA, Yen CP, Shaffrey ME, Lee RR, Shaffrey CI, Wintermark M. Dorsal thoracic arachnoid web and the 'scalpel sign': a distinct clinical-radiologic entity. AJNR Am J Neuroradiol. 2013 May;34(5):1104-10. doi: 10.3174/ajnr.A3432. Epub 2013 Jan 24. PMID: 23348759; PMCID: PMC7964642. 5.Aljuboori Z, Boakye M. Surgical Release of a Dorsal Thoracic Arachnoid Web. World Neurosurg. 2020 Nov;143:289. doi: 10.1016/j.wneu.2020.08.011. Epub 2020 Aug 7. PMID: 32777400. 6.Hines T, Wang C, Duttlinger C, Thompson J, Watford K, Motley B, Wheeler G. Thoracic dorsal arachnoid web with rapid onset of symptoms: A report of two cases and brief review of the literature. Surg Neurol Int. 2021 Jul 6;12:323. doi: 10.25259/SNI_339_2021. PMID: 34345464; PMCID: PMC8326092. 7.Yamamoto A, Fujimoto M, Aoki K, Suzuki Y, Mizuno M, Suzuki H. A Dorsal Arachnoid Web of the Cervical Spine: A Case Report. NMC Case Rep J. 2021 Jun 17;8(1):281-286. doi: 10.2176/nmccrj.cr.2020-0300. PMID: 35079476; PMCID: PMC8769406 8.Inoue J, Miyakoshi N, Hongo M, Kobayashi T, Abe T, Kikuchi K, Abe E, Kasukawa Y, Ishikawa Y, Kudo D, Kinoshita H, Kimura R, Shimada Y. Diagnosis and Surgical Treatment of Thoracic Dorsal Arachnoid Web: A Report of Two Cases. Case Rep Orthop. 2020 Sep 12;2020:8816598. doi: 10.1155/2020/8816598. PMID: 33005467; PMCID: PMC7509563. 9. Nada A, Mahdi E, Mahmoud E, Cousins J, Ahsan H, Leiva-Salinas C. Multi-modality imaging evaluation of the dorsal arachnoid web. Neuroradiol J. 2020 Dec;33(6):508-516. doi: 10.1177/1971400920970919. Epub 2020 Nov 2. PMID: 33135580; PMCID: PMC7788682 10.Laxpati N, Malcolm JG, Tsemo GB, Mustroph C, Saindane AM, Ahmad F, Refai D, Gary MF. Spinal Arachnoid Webs: Presentation, Natural History, and Outcomes in 38 Patients. Neurosurgery. 2021 Oct 13;89(5):917-927. doi: 10.1093/neuros/nyab321. PMID: 34432878. 11.Rodrigues AB, Rodrigues DB, Queiroz JWM, Laube KAC, Braga MCM, Kita WS, De Luna AAANF, De Souza RW, Netto RHD. Surgical treatment of spinal arachnoid web: Report of two cases and literature review. Surg Neurol Int. 2021 Jun 28;12:316. doi: 10.25259/SNI_493_2021. PMID: 34345457; PMCID: PMC8326061 12.Andrews JP, Chan AK, Mummaneni PV. Decompression of a Dorsal Arachnoid Web of the Spine: 2-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2021 Jan 13;20(2):E143. doi: 10.1093/ons/opaa327. PMID: 33289532 13.Hirai T, Taniyama T, Yoshii T, Mizuno K, Okamoto M, Inose H, Yuasa M, Otani K, Shindo S, Nakai O, Okawa A. Clinical Outcomes of Surgical Treatment for Arachnoid Web: A Case Series. Spine Surg Relat Res. 2018 Jul 25;3(1):43-48. doi: 10.22603/ssrr.2018-0027. PMID: 31435550; PMCID: PMC6690113. 14.Buntting CS, Ham Y, Teng KX, Dimou J, Gauden AJ, Nair G. Scalpel sign: Dorsal thoracic arachnoid web, thoracic arachnoid cyst and ventral cord herniation. Radiol Case Rep. 2022 Jul 28;17(10):3564-3569. doi: 10.1016/j.radcr.2022.06.100. PMID: 35923346; PMCID: PMC9340144. 15.Inoue J, Miyakoshi N, Hongo M, Kobayashi T, Abe T, Kikuchi K, Abe E, Kasukawa Y, Ishikawa Y, Kudo D, Kinoshita H, Kimura R, Shimada Y. Diagnosis and Surgical Treatment of Thoracic Dorsal Arachnoid Web: A Report of Two Cases. Case Rep Orthop. 2020 Sep 12;2020:8816598. doi: 10.1155/2020/8816598. PMID: 33005467; PMCID: PMC7509563. 16.Hubbard ME, Hunt MA, Jones KE, Polly DW. Thoracic spinal cord impingement by an arachnoid web at the level of a hemivertebra: case report. J Neurosurg Spine. 2017 Dec;27(6):638-642. doi: 10.3171/2017.5.SPINE161243. Epub 2017 Sep 8. PMID: 28885124 17.Ramos-Fresnedo A, Domingo RA, Clifton W, Jentoft ME, Sandhu SJS, Qui?ones-Hinojosa A. Arachnoid Web Fenestration: Diagnostic and Surgical Nuances. World Neurosurg. 2021 Jun;150:92. doi: 10.1016/j.wneu.2021.03.100. Epub 2021 Mar 31. PMID: 33798776 18.Ruschel LG, Agnoletto GJ, Aurich LA, Vosgerau RP. Dorsal Arachnoid Web and Scalpel Sign: A Diagnostic Imaging Entity. Turk Neurosurg. 2018;28(4):689-690. doi: 10.5137/1019-5149.JTN.18394-16.1. Epub 2016 Oct 14. PMID: 27858382. 19.Wali AR, Birk HS, Martin J, Santiago-Dieppa DR, Ciacci J. Neurosurgical Management of a Thoracic Dorsal Arachnoid Web: Case Illustration. Cureus. 2019 Jun 19;11(6):e4945. doi: 10.7759/cureus.4945. PMID: 31453019; PMCID: PMC6701917. 20.Aljuboori Z, Boakye M. Rare dorsal thoracic arachnoid web mimics spinal cord herniation on imaging. Surg Neurol Int. 2020 Apr 11;11:66. doi: 10.25259/SNI_98_2020. PMID: 32363061; PMCID: PMC7193193. 21.Nieves-Ríos C, Layuno-Matos JG, Olivella G, Ramírez N, Weber-Seda C, Lastra-Power J. Thoracic spinal arachnoid web and syringomyelia with rostral expansion to the first cervical spinal cord level: Case report. Int J Surg Case Rep. 2022 Jun 27;96:107360. doi: 10.1016/j.ijscr.2022.107360. Epub ahead of print. PMID: 35779315; PMCID: PMC9284059. 22.Vergara P, Barone DG. Minimally Invasive Excision of Thoracic Arachnoid Web. World Neurosurg. 2018 Jan;109:e81-e87. doi: 10.1016/j.wneu.2017.09.107. Epub 2017 Sep 23. PMID: 28951269. 23.Nisson PL, Hussain I, H?rtl R, Kim S, Baaj AA. Arachnoid web of the spine: a systematic literature review. J Neurosurg Spine. 2019 Apr 19:1-10. doi: 10.3171/2019.1.SPINE181371. Epub ahead of print. PMID: 31003220. 24、Duran D, Hadzipasic M, Kahle KT. Mystery Case: Acute hydrocephalus caused by radiographically occult fourth ventricular outlet obstruction. Neurology. 2017 Jan 31;88(5):e36-e37. doi: 10.1212/WNL.0000000000003555. PMID: 28138085. 一日不讀書,胸臆無佳想 一月不讀書,耳目失清爽 一部經(jīng)典專著的無私分享 一個專業(yè)知識的摘錄學(xué)習(xí) 一次科普知識的宣講普及 豐富提升自我和造?;颊?/em>
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