Technical Note

Falxuplication, a Novel Method for Wrap-Clipping a Fusiform Aneurysm: Technical

Note

Martin M. Mortazavi1, Tania Hassanzadeh2, Kianoush Khalili1, Sajid S. Suriya1, M. Asif Taqi1, Salman A. Fard1,R. Shane Tubbs3

-BACKGROUND: Various techniques have been used forwrap-clipping a ruptured, fusiform intracranial aneurysm;however, there is no available literature on use of the falxcerebri for wrap-clipping. We present a review of theliterature, with an illustrative case, of a ruptured fusiformpericallosal artery aneurysm firmly attached to the loweredge of the falx cerebri and not amenable to endovascularintervention.

-METHODS: Although the firm attachment between theinferior falx and the fusiform aneurysm was maintained, asection of the lower thinner part of the falx cerebri firmlyattached to the aneurysm was dissected and wrappedaround the fusiform aneurysm, and then stabilized with afenestrated clip. We chose a segment slightly longer thanthe length of the fusiform aneurysm to avoid pree andpostewrap-clipping stenosis.

-RESULTS: Postprocedure, except for a small area ofnumbness on the left distal anterolateral left leg, the pa-tient was neurologically intact and remained neurologi-cally intact at a 12-month follow-up.

-CONCLUSIONS: An inferior thin segment of the falx cer-ebri can be used for wrap-clipping of ruptured fusiformanterior cerebral artery aneurysms. Furthermore, the inferiorfalx can be wrapped around the attached fusiform anteriorcerebral artery aneurysm without compromising flow,offering a safe solution in these unusually complex cases.

Key words- Falx cerebri- Falxuplication- Fusiform aneurysm- Wrap-clipping

Abbreviations and AcronymsACA: Anterior cerebral arteryCT: Computed tomographySAH: Subarachnoid hemorrhage

40 www.SCIENCEDIRECT.com WORLD NE

INTRODUCTION

he overall prevalence of intracranial aneurysms is

approximately 2%e3%,1-3 with peak incidence during the

T sixth decade of life.1 Different reports estimate the

overall risk of aneurysmal rupture at 2e30/100,000 individualsper year.2,4-6 As classified by morphology, intracranial

aneurysms can be saccular, fusiform, or dissecting. Saccularaneurysms are the most common, accounting for 90% of cases

and for most of the morbidity and mortality associated withaneurysmal subarachnoid hemorrhage (SAH).7

Fusiform aneurysms, the focus of this article, are the secondmost common type. They can be defined as a circumferential

dilation of a segment of an intracranial artery lacking a definedorifice of flow, unlike saccular aneurysms.7 Because the inflow

and outflow are longitudinally separate in fusiform aneurysms,resulting in no clearly defined anatomic neck, surgical and

endovascular interventions are challenging.7 Without ananatomic neck akin to saccular aneurysms, fusiform aneurysms

are not easily amenable to clipping or coiling. The reportedprevalence is between 3% and 13% of all intracranial

aneurysms and has increased in recent years.8,9 Atheroscle-rotic fusiform aneurysms have a 5.2% annual mortality risk

owing to rupture or ischemic stroke, compared with 0.51% fornonatherosclerotic fusiform aneurysms.10 Fusiform aneurysm

risk progression is also greater in atherosclerotic patients; theannual risk is 12% for atherosclerotic fusiform aneurysms

versus 1.6% for nonatherosclerotic ones.10 The same studydemonstrated that atherosclerotic fusiform aneurysms are

more likely to be located in the posterior circulation and oflarger diameter, with a mean size of 11.6 mm versus 7.5 mm

for nonatherosclerotic ones.10 It has also been suggested thatarterial dissection can lead to the formation of fusiform

aneurysms.11

From the 1National Skull Base Center, Thousand Oaks, California; 2Banner University MedicalCenter-Tucson, Tucson, Arizona; and 3Seattle Science Foundation, Seattle, Washington, USA

To whom correspondence should be addressed: Martin M. Mortazavi, M.D.[E-mail: m_mortazavi@hotmail.com]

Citation: World Neurosurg. (2018) 109:40-46.https://doi.org/10.1016/j.wneu.2017.09.059

Supplementary digital content available online.

Journal homepage: www.WORLDNEUROSURGERY.org

Available online: www.sciencedirect.com

1878-8750/$ - see front matter ª 2017 Elsevier Inc. All rights reserved.

UROSURGERY, https://doi.org/10.1016/j.wneu.2017.09.059

Figure 1. Preoperative noncontrast computed tomography scan of thehead, axial view, showing suspicious subarachnoid hemorrhage.

TECHNICAL NOTE

Wrap-clipping for fusiform aneurysms has not been widely

studied, but some cases have been reported in the literature.Reported materials for wrap-clipping have historically been non-

autologous. In a case series of 22 patients with fusiform aneu-rysms, 7 were treated with wrap-clipping using either Bemsheet

or periosteum.9 There was 1 reported mortality and 1 case ofcontralateral intracranial hemorrhage. The remaining patients

had fair outcomes or no follow-up. Another series of 48patients with dolichoectatic or fusiform aneurysms reported

wrap-clipping with Gore-Tex in 18 patients (45%).12 There were

Figure 2. Preoperative digital subtraction angiographyimage showing a saccular aneurysm at the rightpericallosal and callosomarginal artery bifurcation and a

WORLD NEUROSURGERY 109: 40-46, JANUARY 2018

no strokes or parent vessel stenoses in the patients who

received wrap-clipping, but 2 patients (11%) experienced recur-rent aneurysms, for which they underwent repeat wrap-clipping

without recurrence for 2 subsequent years.12 Another series of40 patients with dolichoectatic and fusiform aneurysms in the

anterior circulation reported wrap-clipping of 3 cases withmuslin gauze.13 Although the outcomes of these individual

patients were not specified, patients with anterior circulationaneurysms appeared to have better outcomes than those with

aneurysms in the posterior circulation.

Several cases of nontraumatic, distal anterior cerebral artery

(ACA) intracranial aneurysms adherent to the falx cerebri havebeen reported in the literature. One such case involved a saccular

aneurysm in which the dome was adherent to the falx butamenable to clipping.14 Another larger case series of 117 patients

with distal ACA aneurysms also described surgical clipping via aninterhemispheric approach, with consequent sectioning of the

falx; however, the specific number of adherent aneurysms, orany cases of wrap-clipping, were not reported.15 Although dura

mater has been used as an autologous wrap material for wrap-clipping of cerebral aneurysms, there are no reports in the

literature of using the falx cerebri as a wrapping material tospecifically wrap a distal fusiform ACA aneurysm attached to the

falx, or any cases of wrap-clipping using the falx cerebri as anautologous wrap material for aneurysms at other locations. Here

we report a novel method for treating a pericallosal arteryaneurysm.

CLINICAL PRESENTATION

The patient, GCS 15 and Hunt & Hess 1, presented with severeheadache classical for subarachnoid hemorrhage. She had a

small area of light numbness for light touch in the anteromedialdistal third of her left leg. A preoperative computed tomography

(CT) scan showed hyperdensity suspicious for SAH in theinterhemispheric fissue (Figure 1). CT angiography and cerebral

fusiform aneurysm at the pericallosal artery distal to thecallosomarginal takeoff. (A) Anterioposterior (AP) view.(B) Lateral view.

www.WORLDNEUROSURGERY.org 41

Figure 3. Intraoperative dissection revealing both the saccular aneurysmand fusiform aneurysm described in Figure 2.

Figure 5. End result demonstrating clipping of the saccular aneurysm,wrap-clipping of the fusiform aneurysm, and intraoperative indocyaninegreen indicating patency of the parent arteries.

TECHNICAL NOTE

catheter angiography showed a fusiform pericallosal artery

aneurysm immediately distal to the callosomarginal takeoff, anda saccular aneurysm at the pericallosal-callosomarginal junction

(Figures 2 and 3). Endovascular intervention had a high risk of

Video available atWORLDNEUROSURGERY.org

sacrificing the arteries.

The patient underwent craniotomy for interhemi-

spheric approach to treat both aneurysms. Therewas mild SAH along the fusiform aneurysm, but no

subarachnoid blood around the saccular aneurysm.The dome of the saccular aneurysms was severely

attached to the lower edge of the falx. The entiremedial aspect of the fusiform aneurysm was

attached to the lower edge of the falx cerebri. Dissection wouldhave put the patient at high risk for aneurysm rerupture and thus

was contraindicated.

Figure 4. Intraoperative photograph of wrap-clipping the fusiformaneurysm at the pericallosal artery using dura mater.

42 www.SCIENCEDIRECT.com WORLD NE

An 8 � 8 mm segment of the lower falx cerebri, with its inferior

edge firmly attached to the medial edge of the fusiform rupturedaneurysm, was sectioned. The falcine graft was then brought

Figure 6. Powrap-clippinflow in the

UROSURG

inferior to the callosomarginal artery and was wrap-ped around the fusiform pericallosal aneurysm

(Figure 4). A fenestrated clip, allowing both thecallosomarginal and the wrapped pericallosal

arteries to pass through the fenestration, stabilizedthe wrapping inferior to the pericallosal artery

(Video 1). The saccular aneurysm at the bifurcationof the pericallosal and callosomarginal arteries was

also clipped with a fenestrated clip. Intraoperative

indocyanine green and micro Doppler ultrasound showed good

flow through both arteries, and a postoperative catheterangiogram showed satisfactory results (Figures 5 and 6). The

stoperative computed tomography angiography showingg of 2 aneurysms using fenestration clips with preservedpericallosal and callosomarginal arteries.

ERY, https://doi.org/10.1016/j.wneu.2017.09.059

Figure 7. Postoperative digital subtraction cerebralangiography image on postoperative day 3 showingstable clipping and good flow in the pericallosal and

callosomarginal arteries. (A) Anteroposterior view. (B)Lateral view.

TECHNICAL NOTE

patient experienced several episodes of vasospasm during her

hospital stay and reported an unchanged small area of mildlydecreased sensation for light touch on her distal anteromedial

left leg. Except for this mild sensory deficit, she left thehospital neurologically intact. A postoperative cerebral catheter

angiogram performed at 3 days after surgery demonstratedpatency of the pericallosal and callosomarginal arteries without

recurrence of either aneurysm (Figure 7).

Figure 8. Twelve-month 3D representation of computed tomographyangiography of the head showing stable clipping of 2 aneurysms.

WORLD NEUROSURGERY 109: 40-46, JANUARY 2018

Except for the small area of decreased sensation for light touch

on her left lower leg, the patient continued to be neurologicallyintact at 6-month and 1-year follow-ups. A cerebral catheter

angiogram at a 1-year follow-up showed no recurrence of theaneurysm, stable appearance of the arterial calibers, and stable

position of the aneurysm clips with preservation of flow in thepericallosal and callosomarginal arteries (Figures 8e11).

DISCUSSION

Our patient presented with a ruptured fusiform pericallosal artery

aneurysm firmly attached to the inferior edge of the falx cerebri,wherein the falx was used as an autologous material to facilitate

wrap-clipping of the aneurysm. The falx cerebri attaches anteri-orly to the crista galli of the ethmoid bone and posteriorly to the

superior surface of the tentorium cerebelli.16,17 Its anteriorsegment is relatively thin but becomes broader as it extends

posteriorly.16,17 The pericallosal artery is thought to be at partic-ular risk for aneurysm formation following head trauma, owing to

shear stress on the arterial wall by the lower edge of the falx.18

Autologous wrap materials that have been discussed in theliterature include pericranium, dura mater, muscle, and fascia.

Autologous materials are easily obtained and can be used inprocedures that are time-sensitive.19 Muscle, dura, and fascia

adhere fairly well to the vessel wall but subsequently

reabsorb in situ, with little granulation tissue formation orfibrosis.20,21 This suggests poor long-term support of the

aneurysm wall. On the other hand, nonautologous materials,such as Bemsheet in particular, show superior adhesion and

proliferation of collagen fibers surrounding the vessel, sug-gesting greater protection against rupture or rerupture of the

aneurysm.20,21 Other nonautologous materials include muslin,gelatin sponge, gauze, hemashield, Teflon, silastic sheet, fibers,

fibrin glue, plastics, silicone, resins, vinyl polymers, andcyanoacrylate adhesives.21

The fibrosis induced by a nonautologous wrap is thought to

protect against late, but not early, rebleeding.21 However,nonautologous materials are also associated with many

www.WORLDNEUROSURGERY.org 43

Figure 9. Twelve-month digital subtraction angiographyimage showing stable clipping and good flow in the

pericallosal and callosomarginal arteries. (A)Anteroposterior view. (B) Lateral view.

TECHNICAL NOTE

adverse effects, including foreign body granuloma,22-24 fibrous

scar,25 optochiasmatic arachnoiditis with progressive bilateralvision loss,26-28 cranial nerve palsy,29 toxic neuropathy,30,31 in-

fections with cerebritis and abscess or fluid accumula-tion,23,32,33 intraluminal thrombosis with arterial

occlusion,32,34,35 and parent vessel narrowing.36 Moreover, anuncontrolled inflammatory response can cause substantial

neurologic damage, even in the presence of an unrupturedaneurysm.23,26-29,32,35,37 Therefore, the risks of using non-

autologous wrap material must be carefully considered againstthe risks of autologous wrap materials for treating aneurysms.

For this patient, with the aneurysm’s medial aspect severelyadherent to the falx cerebri, using the falx cerebri as wrap

material was both time-efficient and practical.

For complex intracranial aneurysms, flow-diverting stents are anew alternative to endovascular coiling.38 Several strategies are

Figure 10. Lateral views of preoperative (A), postoperative (B), and 12-month (C)pericallosal and callosomarginal arteries.

44 www.SCIENCEDIRECT.com WORLD NE

available for intervention in aneurysms not amenable to direct

clipping, especially fusiform aneurysms. Extracranial-intracranialand intracranial-intracranial cerebral artery bypasses allow for

flow reversal, leading to proximal occlusion with or withouttrapping of the parent vessel while limiting postoperative

symptomatic sequelae.39,40

When the parent artery cannot be sacrificed, reinforcement bywrapping is an alternative. This reinforcement prevents

fragmentation of the internal elastic lamina and degeneration ofthe tunica media, decreasing the likelihood of aneurysm recur-

rence.41 Cellulose cotton sheets are commonly used, butgranuloma and toxic neuritis have been reported in reaction to

coarsely woven gauze.37,42-44 Additional artificial materialsinclude Gore-Tex, silastic sheet, Teflon, and Dacron.45-47 Muscle,

fascia, pericranium, or dura mater can be used as autologouswrap materials.19,48-50

angiography showing no aneurysmal recurrence and good flow in both the

UROSURGERY, https://doi.org/10.1016/j.wneu.2017.09.059

Figure 11. Anteroposterior views of preoperative (A),postoperative (B), and 12-month (C) angiography

showing no aneurysmal recurrence and good flow inboth the pericallosal and callosomarginal arteries.

TECHNICAL NOTE

One case series by Kim et al.51 examined longitudinal

outcomes following wrap-clipping with cellulose cotton fab-ric in 24 patients, 10 of whom had fusiform aneurysms. The

authors reported that 87.5% had either healed or stableaneurysms at a 10- to 75-month follow-up.51 Another 9-patient

series reported by Figueiredo et al.52 with 33% fusiformaneurysms used Rayon for wrap-clipping ruptured aneu-

rysms and reported no rebleeding at 2-year mean follow-up(range, 1 month to 3 years). Finally, Cudlip et al.32 explored

wrap-clipping in 15 patients with solitary ruptured aneu-rysms, and found no rebleeding at 1- and 4-year follow-ups

and a Glasgow outcome score of 4 or 5, excluding 1patient from the latter group who died due to myocardial

infarction.

WORLD NEUROSURGERY 109: 40-46, JANUARY 2018

CONCLUSIONSThe inferior thin part of the falx cerebri can safely be used as anautologous material for wrap-clipping of ruptured fusiform anterior

cerebral artery aneurysms, without compromising blood flowthrough the ACA. The length of wrap material used should be

carefully considered, because too short a graft could predispose thepatient to rerupture, and too long a graft could predispose to arterial

stenosis. In this case, an 8 � 8 mm section of the falx was suc-cessfully used to wrap the falx-adherent pericallosal artery without

aneurysm rebleed or recurrence over a 12-month follow-up period.This technique has been termed “falxuplication” to emphasize its

origin and purpose, and to avoid conflict with other techniques. Amultiarm randomized controlled trial comparing falx cerebri with

dura and nonautologous materials is warranted.

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Conflict of interest statement: The authors declare thatthe article content was composed in the absence of anycommercial or financial relationships that could beconstrued as a potential conflict of interest.

An abstract of this paper was presented as an electronicposter at the American Association of NeurologicalSurgeons Annual Scientific Meeting, April 22e26, 2017,Los Angeles, California, USA.

Received 19 June 2017; accepted 9 September 2017

Citation: World Neurosurg. (2018) 109:40-46.https://doi.org/10.1016/j.wneu.2017.09.059

Journal homepage: www.WORLDNEUROSURGERY.org

Available online: www.sciencedirect.com

1878-8750/$ - see front matter ª 2017 Elsevier Inc. Allrights reserved.

s://doi.org/10.1016/j.wneu.2017.09.059