Neurosurg Rev DOI 10.1007/s10143-017-0875-3

CASE REPORT

Flow-diverter in radiation-induced skull base carotid blowout syndrome: do not write it off! Gopinathan Anil 1,2

&

Junwei Zhang 1 & Yew Kwang Ong 3 & Francis Hui 4

Received: 25 April 2017 / Revised: 7 June 2017 / Accepted: 26 June 2017 # Springer-Verlag GmbH Germany 2017

Abstract Post-radiotherapy carotid blowout syndrome (CBS) of the skull base is a rare but often catastrophic complication of head and neck malignancies. The existing literature on the treatment of this condition with flow-diverting devices (FDD) is extremely limited and disappointing. We present a case of impending CBS in a patient previously irradiated for nasopharyngeal cancer that was successfully treated with use of multiple FDDs, adjunctive endonasal packing and delayed reinforcement with pedicled naso-septal flap, yielding an excellent outcome at 14-months follow-up. Notwithstanding the discouraging results in literature, our anecdotal experience suggests that endovascular reconstruction using FDD could be an option with long-term viability in post-radiotherapy CBS involving the skull base when reinforced with a vascularised naso-septal flap.

Introduction Post-irradiation carotid blowout syndrome (CBS) is a rare but often catastrophic complication of head and neck malignancies [1]. For CBS involving the base-skull region, parent vessel occlusion (PVO) is the current mainstay of treatment with covered stent placement a rarely practical alternative [2]. There is limited data, with largely disappointing outcomes, on the use of flow-diverting devices (FDD) in the management of this condition [2–4]. We present a case of CBS involving the proximal cavernous ICA, post-radiotherapy for nasopharyngeal carcinoma (NPC) that was effectively treated with multiple FDD and adjunctive naso-septal flap coverage yielding excellent outcome at 14-month follow-up. Consent, for the publication for this case report and any additional related information was taken from the patient involved in the study.

Keywords Carotid blowout syndrome . Skull base . Pseudoaneurysm . Flow-diverting device

Case report

* Gopinathan Anil [email protected]

1

Department of Diagnostic Imaging, National University Hospital, Level 2 Main Building, 5 Lower Kent Ridge Road, Singapore 119074, Singapore

2

Department of Diagnostic Radiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore

3

Department of Otolaryngology - Head & Neck Surgery, National University Hospital, Singapore, Singapore

4

Department of Neuroradiology, National Neurosciences Institute, Singapore, Singapore

A 72-year-old male, post-irradiation for NPC with malignancy in remission since 21 years presented with epistaxis. It was acutely controlled with posterior nasal packing. There was massive bleeding on attempted removal of the nasal-pack. Hence, it was maintained using a Foley’s catheter. Naso-endoscopy showed clots in the post-nasal space and skull base erosion exposing the ICA, surrounded by necrotic tissue and debris. CT angiogram (Fig. 1) revealed extensive skull base osteoradionecrosis with a pseudoaneurysm in the proximal left cavernous ICA. At catheter angiography, a 4mm lobulated pseudoaneurysm pointing medially from the left proximal cavernous ICA (Fig. 2a) was demonstrated with no active leak. There was no cross-flow at balloon test occlusion (BTO). With the marked tortuousity of the aorto-iliac tree

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Fig. 1 a Sagittal maximum intensity projection CT carotid angiogram demonstrates a pseudoaneurysm (arrowhead) arising from an exposed left cavernous ICA. A large amount of surrounding necrotic tissue and

blood products are seen (dashed arrow). Posterior nasal packing (asterisk) is partially imaged (b). Axial CT image in the bone window settings demonstrates the extensive base-skull erosions on the left side

as well as carotid vessels and underlying severe atherosclerosis, the available covered stents were deemed unsuitable to be safely navigated and deployed in the cavernous ICA. In the vascular neurosurgical opinion, this patient was a poor candidate for external carotid artery (ECA)-ICA bypass. On day 3, we treated this impending CBS with two telescoping FDD (3.75 × 25 mm and 3.75 × 16 mm) (Pipeline Flex, ev3, Irvine, California) . With dual layer of stent coverage, the flow within the pseudoaneurysm turned sluggish (Fig. 2b). Intra-procedurally, intravenous heparin and abciximab as well as a loading dose of aspirin and clopidogrel through the nasogastric tube were given. Post-procedure, oral aspirin and clopidogrel were continued. At 7-days interval, there was no change in the angiographic appearance of the pseudoaneurysm. To promote thrombosis of the pseudoaneurysm, we stopped the

clopidogrel. A repeat angiogram on day 21 showed almost complete exclusion of the pseudoaneurysm. On day 24, the posterior nasal packing was removed with no further epistaxis. Complete angiographic occlusion of the pseudoaneurysm was noted on day 37 (Fig. 2c). A day later, the patient underwent debridement of the necrotic material from the left sphenoid sinus and a vascularised left naso-septal flap was used to cover the exposed left cavernous ICA and upper clivus. The subsequent recovery was uneventful. There was good remodelling of the vessel around the stents that remained widely patent at a 6-months followup angiogram. Naso-endoscopy showed good mucosal healing in the left sphenoid sinus. The patient remains well at 14-months follow-up with no recurrence of the pseudoaneurysm or rebleeding.

Fig. 2 Panel a demonstrates the pseudoaneurysm (arrow) in the working projection. Note the microcatheter traversing the cavernous ICA and bulbous appearance of the caroticoophthalmic segment. b In the substracted (right) and corresponding native (left) image immediately after deployment of two telescoping flow diverters, there is some stasis of flow within the pseudoaneurysm (arrow). c The follow-up angiogram performed at 5 weeks shows no flow within the pseudoaneurysm and remodelling of the vessel

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Discussion There are three categories of CBS—threatened (eventual haemorrhage is inevitable from a visibly exposed carotid vessel), impending (episodic sentinel haemorrhages from a pseudoaneurysm that resolve spontaneously or with packing) and acute (profuse haemorrhage not confined by a pseudoaneurysm, that is not well-controlled with packing) [1]. Open surgery carries high morbidity and mortality (40 and 60% respectively); hence, CBS is primarily managed by endovascular PVO [1, 2]. However, in patients who fail BTO, PVO carries prohibitively high risk of fatal/severely disabling stroke. In such cases, an ECA-ICA bypass surgery followed by early (within 24-h of bypass) PVO is a reasonable option. However, our patient was deemed as a poor candidate for bypass in view of the extensive atherosclerotic changes in the ECA territory (likely from post-radiotherapy accelerated atherosclerosis) and diffuse skin changes. A covered stent may provide a good initial outcome in CBS; however, it is associated with the medium- to long-term complications of rebleeding (up to 30%), infection (up to 30%) and thromboembolic phenomena [2, 5]. Majority of the reported successful use of covered stents has been in the cervical ICA that has a relatively straight anatomy compared to the ICA at the skull base. The covered stents available in our country are designed for peripheral vascular use and too stiff to be safely navigated into or to conform to the tortuous anatomy of the ICA at the base-skull. There is limited literature on the use of FDD in postradiotherapy skull base CBS. In a series of 15 patients by Wan et al., the only patient treated with FDD for petrous ICA CBS was complicated with early rebleed and a major ischaemic complication [2]. Wong et al. described a similar case treated with FDD and coil embolisation that was complicated by intracerebral haemorrhage and in-stent thrombosis [3]. Tsang et al. reported a series of 7 patients with skull base CBS treated with FDD [4]. While successful obliteration of the pseudoaneurysm was achieved in all cases, there was one peri-procedural infarct and three delayed (between 5 and 10 months) in-stent thromboses. The authors advise against the use of FDD in skull base CBS as first line of treatment. In comparison, patients with post-surgical skull base ICA injuries appear more amenable to treatment with FDD [6]. However, such instances are also few within all 7 cases reported in published literature [6]. Besides, the underlying pathology in post-irradiation CBS is quite different. Post-radiotherapy, the tissue surrounding the pseudoaneurysm is unhealthy and often necrotic with very high risk of infection [7]. A FDD works by reducing the inflow into an aneurysm, gradual thrombosis of the sac and re-endothelialisation of the parent artery. In previously irradiated tissue with multiple FDD, such endothelialisation may be delayed [3.4]. In patients with osteoradionecrosis, the recurrent inflammation and potential

for infection can lead to exposure and progressive breakdown of the carotid wall and haemorrhage [8, 9]. Such limitations are rare in post-surgical ICA injury. Besides, the risk of rebleeding often tempers the duration of anti-platelet therapy, leading to increased thromboembolic complications [3, 4]. The favourable outcome in our patient may be attributed to interplay of multiple factors. Firstly, we did not aim to achieve instantaneous occlusion of the pseudoaneurysm. With two overlapping FDD, when the flow within the pseudoaneurysm became sluggish we decided against a third stent to reduce thromboembolic risk. Instead, we continued the nasal packing and ensured that there was optimal medical control of the blood pressure and antibiotic cover to reduce risk of infection. Post-procedure, the patient was kept asleep and extubated around 24 h later. Our dosage of abciximab and oral antiplatelet agents worked out to be optimal for this patient. Stopping clopidogrel 1 week from the flow-diversion to promote the thrombosis of the pseudoaneurysm yielded the desired results. We believe the delayed reinforcement with vascularised naso-septal played a major role in sustaining the favourable immediate outcome obtained with FDD. Pedicled naso-septal flap promotes wound healing by attenuating the underlying hypoxic and inflammatory pathophysiology and is an effective remedy against the risk of progressive carotid-wall breakdown as well as infection [10]. To the best of our knowledge, there are no previous published reports on such a combination of endovascular reconstruction and adjunctive pedicled naso-septal flap coverage in treating postirradiation CBS of the skull base. We do not recommend the afore-described approach of managing CBS with FDD as a standard of care. In permissible cases, PVO with or without a distal bypass still remains the most definitive and probably safest option. Use of FDD in CBS has several limitations; some of the critical ones being (a) occlusion of the pseudoaneurysm is a relatively gradual process and not instantaneous, (b) need for use of anticoagulation and antiplatelets that can potentially lead to a catastrophic bleed from the partially secured pseudoaneurysm or elsewhere (especially if patient needs any other surgical intervention), (c) higher risk of thromboembolic complications in the absence of optimum antiplatelet premedication and (d) higher cost, since such cases often require two or more FDD in the same patient. However, it can be considered as a reasonable option for salvage therapy in special circumstances.

Conclusion Notwithstanding the uninspiring results in recently published literature, our anecdotal experience suggests that in skull base CBS, flow-diverstion still remains a viable option. However, optimum use of adjunctive measures such nasal packing in the acute phase and delayed reinforcement with vascularised

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pedicle graft to reduce the risk of further inflammatory insult and promote surrounding tissue healing is probably vital in sustaining the success of the endovascular reconstruction.

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Compliance with ethical standards Funding No funding was recieved.

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Conflict of interest The authors declare that they have no conflict of interest. Ethical review No ethics committee approval required for case reports at our institute. Informed consent Informed consent was obtained from the patient for publishing this as a case report.

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