Andreas Raabe, Jürgen Beck, Stefan Rohde, Joachim Berkefeld and Volker Seifert
The aim of this study was to investigate the feasibility of integrating three-dimensional rotational angiography (3D-RA) data into a surgical navigation system and to assess its accuracy and potential clinical benefit.
The study cohort consisted of 16 patients with 16 intracranial aneurysms who had been scheduled for routine or emergency surgery. Rotational angiography data were exported using a virtual reality modeling language file format and imported into the BrainLAB VectorVision2 image-guided surgery equipment. During 3D-RA the position of the head was measured using a special headframe. The authors also determined the accuracy of 3D-RA image guidance and the clinical benefit as judged by the surgeon, including, for example, early identification of branching vessels and the aneurysm.
There was good correspondence between the 3D-RA–based navigation data and the intraoperative vascular anatomy in all cases, with a maximum error of 9° of angulation and 9° of rotation. In eight cases, the surgeon determined that the 3D-RA image guidance facilitated the surgical procedure by predicting the location of the aneurysm or the origin of a branching artery that had been covered by brain tissue and blood clots.
The integration of 3D-RA into surgical navigation systems is feasible, but it currently requires a new perspective-registration technique. The intraoperative 3D view provides useful information about the vascular anatomy and may improve the quality of aneurysm surgery in selected cases.
Patrick Schuss, Erdem Güresir, Joachim Berkefeld, Volker Seifert and Hartmut Vatter
Intracranial aneurysms of the anterior circulation might become symptomatic by causing visual deficits. The influence of treatment modality on improvement is still unclear. The objective of this study was to analyze the recovery of visual deficits caused by the mass effect of intracranial aneurysms after surgical clipping or endovascular treatment.
Between June 1999 and December 2009, 20 patients with unruptured intracranial aneurysms causing visual dysfunction due to compression of the optical nerve were treated at the authors' institution. Visual deficits were recorded at admission and at follow-up. To evaluate a larger number of patients, MEDLINE was searched for published studies involving visual disturbance caused by an aneurysm. A multivariate analysis was performed to find independent predictors for favorable visual outcome.
Nine (75%) of 12 patients treated surgically achieved improvement of visual symptoms, compared with 3 (38%) of 8 patients treated endovascularly. A literature review, including the current series, revealed a total of 165 patients with UIAs causing visual dysfunction. Surgical treatment was associated with a significantly higher rate of visual improvement (p = 0.002) compared with endovascular treatment. According to the multivariate analysis, surgical clipping was the only variable significantly associated with improvement of visual outcome (p = 0.02).
Aneurysm-related visual dysfunction developed from direct mechanical compression may improve after surgical clipping and endovascular coiling. However, based on the present series combined with pooled analysis of data from the literature, the only factor significantly associated with improvement of visual dysfunction was surgical clipping.
Johannes Platz, Marlies Wagner, Erdem Güresir, Se-Jong You, Juergen Konczalla, Richard du Mesnil de Rochemont, Joachim Berkefeld and Volker Seifert
Diffusion-weighted MRI was used to assess periprocedural lesion load after repair of unruptured intracranial aneurysms (UIA) by microsurgical clipping (MC) and endovascular coiling (EC).
Patients with UIA were assigned to undergo MC or EC according to interdisciplinary consensus and underwent diffusion-weighted imaging (DWI) 1 day before and 1 day after aneurysm treatment. Newly detected lesions by DWI after treatment were the primary end point of this prospective study. Lesions detected by DWI were categorized as follows: A) 1–3 DWI spots < 10 mm, B) > 3 DWI spots < 10 mm, C) single DWI lesion > 10 mm, or D) DWI lesion related to surgical access.
Between 2010 and 2014, 99 cases were included. Sixty-two UIA were treated by MC and 37 by EC. There were no significant differences between groups in age, sex, aneurysm size, occurrence of multiple aneurysms in 1 patient, or presence of lesions detected by DWI before treatment. Aneurysms treated by EC were significantly more often located in the posterior circulation (p < 0.001). Diffusion-weighted MRI detected new lesions in 27 (43.5%) and 20 (54.1%) patients after MC and EC, respectively (not significant). The pattern of lesions detected by DWI varied significantly between groups (p < 0.001). Microembolic lesions (A and B) found on DWI were detected more frequently after EC (A, 14 cases; B, 5 cases) than after MC (A, 5 cases), whereas C and D were rare after EC (C, 1 case) and occurred more often after MC (C, 12 cases and D, 10 cases). No procedure-related unfavorable outcomes were detected.
According to the specific techniques, lesion patterns differ between MC and EC, whereas the frequency of new lesions found on DWI is similar after occlusion of UIA. In general, the lesion load was low in both groups, and lesions were clinically silent.
Clinical trial registration no.: NCT01490463 (clinicaltrials.gov)
Jürgen Beck, Andreas Raabe, Heiner Lanfermann, Joachim Berkefeld, Richard Du Mesnil De Rochemont, Friedhelm Zanella, Volker Seifert and Stefan Weidauer
The aim of this study was to analyze the effects and outcome of transluminal balloon angioplasty (TBA) on brain tissue perfusion by using combined perfusion- and diffusion-weighted (PW/DW) magnetic resonance (MR) imaging in patients with cerebral vasospasm after subarachnoid hemorrhage.
Ten consecutive patients with cerebral vasospasm treated using TBA were included in this prospective study. Hemodynamically relevant vasospasm was diagnosed using a standardized PW/DW MR imaging protocol. Digital subtraction angiography was used to confirm vasospasm, and TBA was performed to dilate vasospastic arteries. The PW/DW imaging protocol was repeated after TBA. The evaluation of the passage of contrast medium after standardized application using the bolus tracking method allowed for the calculation of the time to peak (TTP) before and after TBA.
Tissue at risk was defined based on perfusion delays in individual vessel territories compared with those in reference territories. In cases with proximal focal vasospasm, TBA could dilate spastic arteries. Follow-up PW/DW MR imaging showed the disappearance of, or a decrease in, the mismatch. A TBA-induced reduction in the perfusion delay of 6.2 ± 1 seconds (mean ± standard error of the mean) to 1.5 ± 0.45 seconds resulted in the complete prevention of infarction; a reduction in the delay of 6.2 ± 2.7 to 4.1 ± 1.9 seconds resulted in the preservation of those brain tissue parts having only small infarcts in the vessel territories. Without TBA, however, the perfusion delay remained or even increased (11.1 ± 3.7 seconds), and the complete infarction of a territory occurred.
Angioplasty of vasospastic arteries leads to hemodynamic effects that can be quantified using PW/DW MR imaging. In cases of a severe PW/DW imaging mismatch successful TBA improved tissue perfusion and prevented cerebral infarction. The clinical significance of PW/DW MR imaging and the concept of tissue at risk is shown by cerebral infarction in vessels not accessible by TBA.