ORIGINAL PAPER/ARTYKUŁ ORYGINALNY
Assessment of long-term results of intracranial aneurysm clipping by means of computed tomography angiographyOcena skuteczności klipsowania tętniaków wewnątrzczaszkowych w terminie odległym za pomocą angiografii tomografii komputerowej

https://doi.org/10.5114/ninp.2012.31549Get rights and content

Abstract

Background and purpose

The aim of this retrospective study was to assess the effectiveness of aneurysm clipping by computed tomography angiography (CTA) in a long-term follow-up.

Material and methods

The CTA examination was performed in 119 patients who had 143 aneurysms clipped. The examinations were performed 3 to 11 years (mean 6 years) after clipping using a GE Lightspeed PRO16 scanner.

Results

In all cases but one, good quality CTA images, suitable for evaluation of the arteries around the clip site, were obtained. Complete aneurysm closure without neck remnant or regrowth was confirmed in 137 (96%) aneurysms. In 4 (3%) cases, neck remnants were detected (2 on the anterior communicating artery [AComA] and 2 on the middle cerebral artery [MCA]). A total clip slippage from the aneurysm dome was revealed in 1 case. One case of aneurysm re-rupture was noted, 11 years after clipping. The rebleeding was caused by AComA aneurysm regrowth. Among these 6 patients with unsatisfactory clipping, 2 required further treatment and 4 remain under observation. Nineteen ‘de novo’ aneurysms in other locations were found in 14 (12%) patients. Summing up all of the pathological findings in the study group, there were 18 (15%) patients who needed further management including close surveillance or re-treatment.

Conclusions

Computed tomography angiography is a simple and reliable method of aneurysm clipping evaluation. The long-term follow-up CTA confirmed the permanent and complete obliteration of 96% of the aneurysms. The rate of unsatisfactory aneurysm closure was 4%, but only 1.4% needed re-treatment during a mean follow-up of 6 years. The annual risk of aneurysm re-rupture was 0.1%.

Streszczenie

Wstęp i cel pracy

Celem niniejszej retrospektywnej pracy była ocena skuteczności klipsowania tętniaków wewnątrzczaszkowych w odległym terminie po operacji za pomocą angiografii tomografii komputerowej (angio-TK).

Materiał i metody

Angio-TK wykonano u 119 pacjentów ze 143 zaklipsowanymi tętniakami. Badania przeprowadzano w ciągu 3–11 lat od operacji (średnio 6 lat) aparatem CT GE Lightspeed PRO16.

Wyniki

U wszystkich pacjentów, poza jednym, uzyskano obrazy pozwalające na wiarygodną ocenę naczyń w pobliżu założonego klipsa. Spośród 143 zaklipsowanych tętniaków, w 137 (96%) przypadkach stwierdzono prawidłowe zamknięcie, bez cech odtwarzania się ani pozostałości tętniaka. Pozostałość szyi klipsowanego tętniaka (2 na tętnicy łączącej przedniej i 2 na tętnicy mózgu środkowej) stwierdzono w 4 przypadkach. W jednym przypadku uwidoczniono całkowite zsunięcie się klipsa z tętniaka tętnicy łączącej przedniej. W okresie objętym analizą zanotowano jeden przypadek nawrotowego krwotoku podpajęczynówkowego po 11 latach od operacji. Powodem był odrost tętniaka tętnicy łączącej przedniej. Spośród 6 chorych z niezadowalającym zaklipsowaniem, 2 wymagało dalszego leczenia, a 4 – obserwacji. U 14 (12%) pacjentów wykryto 19 tętniaków de novo w innych lokalizacjach, z których 18 nie wymagało leczenia. Biorąc pod uwagę wszystkie nieprawidłowości naczyniowe w badanej grupie, 18 (15%) pacjentów wymagało dalszej obserwacji lub leczenia.

Wnioski

W ocenie autorów angio-TK jest wygodnym i wiarygodnym sposobem kontroli po operacjach zaklipsowania tętniaka. Odległe badania angio-TK wykazały, że klipsowanie całkowicie i trwale wyłącza z krążenia 96% tętniaków. Odsetek niezadowalającego zaklipsowania wyniósł 4%, ale tylko 1,4% pacjentów wymagało dalszego leczenia w okresie obserwacji wynoszącym średnio 6 lat. Ryzyko ponownego krwotoku z zaklipsowanego tętniaka wyniosło 0,1% na rok.

Introduction

The gold standard for the detection of cerebral aneurysms and also for checking the accuracy of aneurysm clipping is digital subtraction angiography (DSA) [1]. However, due to its invasiveness, DSA has not been widely used as a follow-up examination to assess the long-term effectiveness of aneurysm clipping [2]. The introduction of computed tomography angiography (CTA) for detecting intracranial aneurysms has made it possible to limit the invasiveness of the diagnostics, compared to DSA. High sensitivity and specificity of CTA have recently been proven for detecting very small aneurysms [3, 4] and as a useful diagnostic modality to check aneurysm occlusion after clipping [5, 6]. Due to simplicity and availability, CTA is now widely used in the diagnosis of patients after subarachnoid haemorrhage (SAH), and the use of this method is encouraged to control the completeness of aneurysm clipping. A similar trend toward less invasive methods can be seen in interventional radiology, where the long-term results of coiling can be effectively evaluated with magnetic resonance angiography (MRA) instead of DSA [7].

Knowledge of remote results of aneurysm clipping is mandatory, due to the development of endovascular modalities. Several years ago, the neurosurgical community demanded from interventional radiologists a long-term evaluation of coiling effectiveness. Currently, this is well documented [7] and it should be balanced by an objective assessment of clipping durability. Thus, we initiated long-term follow-up examinations in patients after aneurysmal subarachnoid haemorrhage treated by clipping. The aim of the study was to evaluate the efficacy and durability of clipping by means of a CTA examination performed many years after surgery.

Section snippets

Material and methods

Patients were qualified for this retrospective study if at least three years had passed since the clipping of ruptured intracranial aneurysm. Exclusion criteria were severe general and neurological conditions at the time of discharge from hospital. Invitations for a follow-up CTA examination were sent to 208 patients who underwent surgery between 1998 and 2005. The clips used before 1998, made of a different alloy, caused significant artefacts in CTA scans that hindered adequate evaluation of

Results

We did not observe any complications after intravenous administration of the contrast medium. In all but one patient, good quality CTA images were obtained, suitable for the evaluation of arteries around the clip site. In one case, significant artefacts around the clips were visible, but in spite of this, aneurysm regrowth was clearly visible, and so the patient was not excluded from the analysis. Of the 143 clipped aneurysms in 137 (96%) cases, complete aneurysm closure without residual neck

Clip slippage

In one case (0.7%) a total clip dislocation from the aneurysm dome was found (Fig 1I). The aneurysm was located on AComA. For accurate interpretation, the follow-up CTA was compared with preoperative CTA and the surgery report was also analysed. In the preoperative study, the aneurysm looked the same. There was no inconsistency between preoperative CTA and the intraoperative image. There were no rebleeding episodes and no perceptible enlargement of the aneurysm during 3 years of follow-up. The

Aneurysm re-rupture

Only one (0.7%) case of recurrent SAH was noted during the period of interest. This patient underwent surgery for ruptured AComA aneurysm 11 years ago. The cause of rebleeding was aneurysm regrowth at the site of previous clipping (Fig 1G-H). The recurrent SAH and source of rebleeding were established based on clinical symptoms, CT scan and CTA examination. The patient was operated on again. During the same procedure the aneurysm regrowth and unruptured ‘de novo’ MCA aneurysm were clipped and

Neck remnants

In 4 (2.8%) cases, neck remnants were detected. Two of them were located on AComA and two on MCA (Fig 1D-F). However, we cannot be sure whether these findings were definitely remnants or regrowths, because early vascular imaging was not performed. On the other hand, based on an analysis of preoperative aneurysm shape and operative descriptions, we assume that small remnants could remain in these cases. This could be expected due to a complex anatomical configuration and the narrowing of the

Durability of aneurysm clipping

In the past, the only examination for evaluation of the efficacy of aneurysm clipping was DSA. However, DSA has not been widely performed in long-term follow-up due to its invasiveness. Over the last two decades, more publications on this topic have appeared because of the need for comparison of the efficacy of two modalities: clipping and coiling [8, 9, 10, 11]. In a series of DSA performed in the Barrow Neurological Institute (Phoenix, USA) at a mean of 4.4 years post surgery, the overall

Conclusions

Computed tomography angiography is a simple and reliable method of aneurysm clipping evaluation. Long-term follow-up CTA confirmed permanent and complete obliteration in 96% of aneurysms. The rate of unsatisfactory aneurysm closure was 4%, but only 1.4% needed re-treatment during a mean follow-up of 6 years. The annual risk of rebleeding due to aneurysm regrowth was 0.1%. The satisfactory durability of clipping justifies long-term screening only in patients with risk factors for rebleeding.

Disclosure

Authors report no conflict of interest.

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