Preoperative embolization plays a significant role as an adjunct to surgical intervention in the cases of certain vascular tumours of the brain. While the procedure has resulted in facilitated resection of the tumour, and has reduced morbidity and mortality, its application remains debatable within the neurosurgical community, owing to rare, but major post-procedural complications. Herein, we have reviewed the literature to assess the safety and efficacy of preoperative angiographic embolization for brain tumours

Baig, Ahmer Nasir

Hani, Ummey

Salam, Basit

Shamim, Muhammad Shahzad

English

eCommons@AKU

eCommons@AKU Section of Neurosurgery Department of Surgery 1-1-2021 Role of preoperative embolization in management of central nervous system tumours Ummey Hani Ahmer Nasir Baig Muhammad Shahzad Shamim Basit Salam Follow this and additional works at: https://ecommons.aku.edu/pakistan_fhs_mc_surg_neurosurg  Part of the Neurology Commons, Neurosurgery Commons, Oncology Commons, Radiology Commons, and the Surgery Commons 172Vol. 71, No. 1-A, January 2021AbstractPreoperative embolization plays a significant role as anadjunct to surgical intervention in the cases of certainvascular tumours of the brain. While the procedure hasresulted in facilitated resection of the tumour, and hasreduced morbidity and mortality, its application remainsdebatable within the neurosurgical community, owing torare, but major post-procedural complications. Herein, wehave reviewed the literature to assess the safety andefficacy of preoperative angiographic embolization forbrain tumours.  Keywords: embolization; brain tumor; skull base tumor;angiographic embolization; IntroductionDespite advances in microsurgical techniques,management of vascular brain tumours is complex, andrequires a multi-disciplinary approach.1,2 Pre-operativeembolization (PEm) was first described in the 1970s, andhas slowly gained acceptance amongst the neurosurgicalcommunity, as an adjunct to brain tumour surgery forhyper-vascular tumours.1 Tumour embolization refers toany procedure performed either percutaneously, througha direct puncture of the tumour (DPT),  or via a trans-arterialapproach, in which embolic material is injected with thegoal of reducing tumour vascularity, hence, minimizingmorbidity and improving chances of successful tumourresection.1 The latter is facilitated through necroticsoftening of the tumour, making it more easily resectable.3Embolization of extra-axial tumours such as meningiomas,performed in the territory of external carotid artery (ECA),is generally safer than embolization of intra-axial tumourssuch as haemangioblastoma, which derive their vascularsupply from internal carotid artery (ICA) or vertebrobasilarartery (VBA).2 Most commonly employed embolisatesinclude particles such as Poly Vinyl Alcohol (PVA) andtrisacryl gelatin microspheres (TAGM), as well as liquidembolic agents such as Onyx and N-Butyl Cyanoacrylate(NBCA).3 There are multiple objectives for pre-operativedevascularization of the tumour, the most important beingminimizing blood loss, and decreasing operating time.Other benefits include their use in palliation, by decreasingtumour size and reducing pain in patients not fit forsurgery.1However, some authors have questioned the utility of PEm,in the light of questionable cost-effectiveness and the riskof post-procedural complications. In this paper, we havereviewed the technical efficacy, safety, and outcomes ofpre-operative brain tumour embolization. Review of Literature Kubota et al., published a case of a patient undergoingsurgery for a huge, right-sided tentorial epithelioidhaemangioendothelioma (E-HE), in which authors had toabort surgery due to haemorrhage. The patient underwentembolization with PVA of the right ECA partially feedingthe tumour five days before second surgery. Subsequentgross-total removal of the tumour was relatively bloodless,and no recurrence was reported even nine years later,suggesting PEm to be rational in cases of E-HE.4 Duffis etal., proposed their highly cited guidelines for embolizationin 2012.1 Non-invasive imaging was suggested to allowdelineation of the extent of tumour and digital subtractionangiography (DSA), along with super-selectivecatheterization of ECA was recommended to allow foridentification of displaced feeders, presence of collateralflow distal to the involved carotid; and to reveal intracranialanastomoses. Tumour blush was proposed as a radiologicmeasure of procedural efficacy. According to the authors,tumour resection within 24 hours of embolization was tobe avoided and a delay of 1 to 8 days from embolizationwas recommended. However, the timing for surgery afterembolization remains controversial and some authorsadvocate resecting the neoplasm immediately, or within aEVIDENCE BASED NEURO-ONCOLOGY Role of Preoperative Embolization in Management of Central Nervous System TumoursUmmey Hani,1 Ahmer Nasir Baig,2 Muhammad Shahzad Shamim,3 Basit Salam41Final Year Student, Jinnah Sindh  Medical University, 2-4The Aga Khan University Hospital, Karachi, Pakistan.Correspondence: Muhammad Shahzad Shamim. e-mail: shahzad.shamim@aku.eduFigure:  A) and B), Digital subtraction angiogram, pre and post embolization lateralviews, of a meningioma supplied by the ECA.A) B)day, to avoid potential worsening of peritumoral oedema.5Steroid use was also advised in tumours at risk of post-embolization oedema. Wang et al., published the outcome of PEm in eightpaediatric brain tumour patients over eight years, andreported good results with embolization as a surgicaladjunct.2 Embolization was done with either NBCA orTAGM. Four out of the eight cases were of choroid plexuspapilloma, and two of these patients, both embolized withTAGM, developed tumour bleeds.2 Hanak et al.,retrospectively reviewed 15 patients, who underwent 17PEm for haemangiopericytomas (HPC) at two centers. Moreextensive devascularization was achieved for HPCs withprimarily ECA blood supply, than those with ICA/VBAcirculation. The authors reported an average time intervalof 2.2 days between embolization and surgery, with nogreater than 500 ml blood loss in tumours that achieved80% devascularization. The authors, however, did notnotice any significant difference in gross total removal ofembolized versus non-embolized tumours.3In a systematic review of PEm for intradural spinalhaemangioblastoma (HB), Ampie et al., analyzed 29reported cases. The most commonly utilized embolisatewas (PVA), followed by TAGM and NBCA. Excellent rates ofgross total resection (GTR) were reported, with estimatedblood loss (EBL) averaging up to 187.5 ml. Complicationsfrom embolization and surgery were minimal, with nodeaths or permanent neurological morbidity. The authors,however, noted excellent outcomes from microsurgeryalone from historical series, questioning the rationalebehind PEm.6 In another systematic review for intracranialHB, Ampie et al., reported that PEm did not increase GTRrates and failed to reduce blood loss and complications,rather itself significantly carrying the aforementioned risks.In a total of 111 patients compared to 392 non embolizedones, GTR was achieved in 83.7% and 95.6% of the patients,respectively. Intraoperative blood transfusion was requiredin 15.3% of embolized and 0.51% of non-embolizedcontrols, while rates of postoperative haemorrhage were8.4% and 1.6%, respectively. Complication rates fromembolization were 11.7% and following consequentsurgery were 20.7%, deeming PEm as inconsequential inthe authors’ view.5Ampreechakul et al., examined the efficacy of PEm in aretrospective analysis of 37 tumours, which included 18meningiomas, six haemangioblastomas, and sixhaemangiopericytomas, among others.7 Indications toembolize included bleeding diatheses, hypervasculartumour type, presence of multiple flow-voids on MRI, deep-seated tumours, and tumours with intratumoralaneurysms. Failure of PEm occurred in four patients andmedian time to surgery after PEm was seven days.Statistically significant negative correlation of angiographicdevascularization percentage and EBL was noticed, provingthe former to be the only true predictor of proceduralefficacy. In a prospective study of 14 patients, Gruber et al.,described longitudinal image changes in supratentorialhemispheric meningiomas based on MRI after PEm usingcalibrated microspheres. The authors reported sustainabletissue transformation and significant decrease in specificparameters such as baseline apparent diffusion coefficient;baseline mean ratios of relative cerebral blood volume,relative cerebral blood flow, and viable enhanced baselinemean tumour volume, within 6 hours and 48 hours ofembolization.8More recently, Barros et al., published their retrospectiveanalysis of 139 meningiomas, describing anatomiclocations and vascular supplies to identify characteristicspredictive of successful PEm. Seventy-eight percent oftumours were successfully embolized, with a 2.8%periprocedural complication rate. Within the subset ofpatients with successful embolization, 31% achievedcomplete angiographic embolization. Significantmultivariate predictors of embolization weremeningohypophyseal trunk, middle meningeal artery, andascending pharyngeal artery supply, as well as convexityor parasagittal location, the latter two most likely to achievecomplete angiographic embolization.9Duffis et al., reported stroke and intracerebral haemorrhagein up to 3-6% cases of PEm. While both particulate andliquid emolisates were used, the former was linked togreater complication rates, a notion supported by Wang etal., too.1,2 In another study with intradural spinal HB casesundergoing PEm, transient post-embolizationcomplications were rare, and included swallowing difficulty(3.5%), decreased position sense (3.5%), and spasticity(3.5%).6 However, in the cerebellar subset of the sametumour, complications were more common, and includedpost-procedural haemorrhage, ischaemic infarcts,dysarthria, hemiparesis, and hemisensory impairment,although mortality rates were not significantly differentcompared to non-embolized cohort.5 In their retrospectivereview of 39 patients, Tanaka et al., described five patientswith worsening of existing neurological symptoms,explained as an inflammatory response, a condition theytermed as post-embolization neurological syndrome(PENS).10 In another retrospective analysis of PEm inmeningioma patients by Barros et al., the authors reportedthree procedure-related complications including middlemeningeal artery that required coiling; self-resolvedcatheter-induced vasospasm, and a cervical ICA dissection.9173J Pak Med AssocU .Hani, A.N. Baig, M.S. Shamim, et al.ConclusionPEm of hypervascular brain tumours has a high technicalsuccess rate as a surgical adjunct, but also carries areasonable risk of complications. The authors thereforerecommend judicious utilization of this treatment adjunct.References 1. Duffis EJ, Gandhi CD, Prestigiacomo CJ, Abruzzo T, Albuquerque F,Bulsara KR, et al. Head, neck, and brain tumor embolization guide-lines. J. Neurointerv. Surg.. 2012;4:251-5.2. Wang HH, Luo CB, Guo WY, Wu HM, Lirng JF, Wong TT, et al. Preoper-ative embolization of hypervascular pediatric brain tumors: evalua-tion of technical safety and outcome. Official journal of theInternational Society for Pediatric Neurosurgery. Childs Nerv Syst2013;29:2043-9.3. Hanak BW, Haussen DC, Ambekar S, Ferreira M, Jr., Ghodke BV, Pe-terson EC. Preoperative embolization of intracranial hemangioperi-cytomas: case series and introduction of the transtumoralembolization technique. J. Neurointerv. Surg. 2016;8:1084-94.4. Kubota T, Sato K, Takeuchi H, Handa Y. Successful removal after ra-diotherapy and vascular embolization in a huge tentorial epithelioidhemangioendothelioma: a case report. J Neuro-oncol. 2004;68:177-83.5. Ampie L, Choy W, Lamano JB, Kesavabhotla K, Kaur R, Parsa AT, et al.Safety and outcomes of preoperative embolization of intracranialhemangioblastomas: A systematic review. Clin. Neurol. Neurosurg..2016;150:143-51.6. Ampie L, Choy W, Khanna R, Smith ZA, Dahdaleh NS, Parsa AT, et al.Role of preoperative embolization for intradural spinal heman-gioblastomas. J. Clin. Neurosci: official journal of the NeurosurgicalSociety of Australasia. 2016;24:83-7.7. Iampreechakul P, Tirakotai W, Lertbutsayanukul P, Siriwimonmas S,Liengudom A. Pre-operative Embolization of Intracranial and Ex-tracranial Tumors: A Review of 37 Cases. J Med Assoc Thai. 2016;99Suppl 3:S91-119.8. Gruber P, Schwyzer L, Klinger E, Burn F, Diepers M, Anon J, et al. Lon-gitudinal Imaging of Tumor Volume, Diffusivity, and Perfusion AfterPreoperative Endovascular Embolization in Supratentorial Hemi-spheric Meningiomas. World Neurosurg.. 2018;120:e357-e64.9. Barros G, Feroze AH, Sen R, Kelly CM, Barber J, Hallam DK, et al. Pre-dictors of preoperative endovascular embolization of meningiomas:subanalysis of anatomic location and arterial supply. J. Neurointerv.Surg.. 2020;12:204-8.10. Tanaka Y, Hashimoto T, Watanabe D, Okada H, Kato D, Aoyagi S, et al.Post-embolization neurological syndrome after embolization for in-tracranial and skull base tumors: transient exacerbation of neurolog-ical symptoms with inflammatory responses. Neuroradiol.2018; 60:843-51.174Vol. 71, No. 1-A, January 2021Role of Preoperative Embolization in Management of Central Nervous ………. 

Role of preoperative embolization in management of central nervous system tumours

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Role of preoperative embolization in management of central nervous system tumours

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