Felix Goehre

Transient Cardiac Arrest Induced by Adenosine: A Tool for Contralateral Clipping of Internal Carotid Artery-Ophthalmic Segment Aneurysms.

BACKGROUND The disadvantages of a contralateral approach (CA) include deep and narrow surgical corridors and inconsistent ability to achieve proximal control of the supraclinoid internal carotid artery (ICA). However, a CA remains as a microsurgical option for selected ICA-ophthalmic (opht) segment aneurysms. OBJECTIVE To describe transient cardiac arrest induced by adenosine as an alternative tool to obtain proximal vascular control and soften the aneurysm sac in selected patients while performing a CA. METHODS From January 1998 to December 2013, we retrospectively identified 30 patients with ICA-opht segment aneurysms treated through a CA. Of those, 8 patients received an intravenous bolus of adenosine to induce transient cardiac arrest for softening of the aneurysm sac. We reviewed preoperative clinical status, characteristics of the contralateral aneurysm, adenosine doses, asystole time, recovery of normal circulation, outcome, and complications. RESULTS No preoperative cardiac or pulmonary pathologies were found in the study population. All contralateral ICA-opht segment aneurysms were unruptured, small, and saccular in shape. Transient cardiac arrest was induced because it was impossible to apply a temporary clip on the parent contralateral supraclinoid ICA. The median dose of adenosine was 22.5 mg (range, 5-50 mg) and the asystole time ranged from 20 to 40 seconds. All patients (n = 8) had good postoperative outcomes. No brain infarction or cardiac complications appeared postoperatively. CONCLUSIONS In selected patients, transient cardiac arrest induced by adenosine during a contralateral approach allows a brief flow arrest and softening of the aneurysm for safer exposure and clipping.

Contralateral Approach to Internal Carotid Artery Ophthalmic Segment Aneurysms: Angiographic Analysis and Surgical Results for 30 Patients.

BACKGROUND Contralateral aneurysm clipping can be applied to bilateral intracranial aneurysms of the anterior circulation and to selected aneurysms on the medial wall of the internal carotid artery (ICA). OBJECTIVE To identify anatomic and radiological parameters that would favor a contralateral microsurgical approach to ICA-ophthalmic segment (ICA-opht) aneurysms. METHODS For the period January 1957 to December 2012, we retrospectively analyzed 268 patients with ICA-opht aneurysms treated in our institution. Of these patients, 30 underwent a contralateral approach; 15 patients (50%) had multiple intracranial aneurysms, and 15 patients had a single aneurysm on the contralateral side of the craniotomy. RESULTS Thirty saccular aneurysms located on the contralateral ICA were treated. Six aneurysms (20%) were present in patients with a subarachnoid hemorrhage due to associated aneurysms, whereas 24 aneurysms (80%) had no history of bleeding. Contralateral aneurysms were smaller than 14 mm and showed no wall irregularities, calcifications, or secondary pouches. Projections of the aneurysms were superomedial (n = 23, 77%), medial (n = 4, 13%), and superior (n = 3, 10%). The median prechiasmatic distance was 5.7 mm (range, 3.4-8.7 mm), the median interoptic distance was 10.5 mm (range, 7.6-15.9 mm), and the median distance between both ICAs was 14.7 mm (range, 10.4-21.4 mm). CONCLUSION The contralateral approach for ICA-opht aneurysms remains a treatment option for intracranial aneurysms. Its feasibility depends on specific anatomic parameters related to the aneurysm itself and to the prechiasmatic distance, interoptic distance, and relationship of the ICA with the anterior clinoid process.

Contralateral Approach to Bilateral Middle Cerebral Artery Aneurysms: Comparative Study, Angiographic Analysis, and Surgical Results.

BACKGROUND Bilateral aneurysms located between the 2 middle cerebral artery (MCA) bifurcations may be approachable through a single unilateral approach. OBJECTIVE To identify anatomic parameters based on imaging that would favor a contralateral approach. METHODS From January 1998 to December 2013, we retrospectively identified 173 patients with bilateral intracranial aneurysms. Fifty-one patients had bilateral MCA aneurysms. A total of 38 patients underwent a single craniotomy with a contralateral microsurgical approach (group 1 or contralateral group) and 13 patients underwent bilateral craniotomies (group 2 or bilateral group). For both groups, we analyzed aneurysm characteristics, morphology, size, projections, and distance to the contralateral corridor, as well as surgical time, outcome, and postoperative complications. RESULTS All aneurysms approached contralaterally were unruptured and without wall calcifications. Of the contralaterally approached aneurysms, 97% were smaller than 14 mm. The median length of the contralateral A1 was 13.2 mm (range: 6-19.8 mm) and the median length of the contralateral M1 was 14.2 mm (range: 4.6-21 mm). The contralateral group had a good postoperative outcome (modified Rankin Scale 0-3) in 80% of ruptured cases and 86% of unruptured cases. The median surgical time was 120 minutes (range: 75-255 minutes), 43% shorter than the bilateral group. CONCLUSION The contralateral approach for bilateral MCA aneurysms in selected patients is feasible in experienced hands, with acceptable morbidity and mortality. The contralateral approach requires a meticulous preoperative analysis of the characteristics of the aneurysms to be clipped and of the anatomic constraints of the microsurgical operative corridor. ABBREVIATIONS A1, anterior cerebral artery proximal segmentbMCA, bilateral middle cerebral arteryCTA, computed tomographic angiographyHH, Hunt-Hess scaleIA, intracranial aneurysmsICA, internal carotid arteryICAbif, internal carotid artery bifurcationMCA, middle cerebral arteryM1, middle cerebral artery proximal segmentmRS, modified Rankin ScaleSAH, subarachnoid hemorrhage.

Double-clip technique for the microneurosurgical management of very small (< 3 mm) intracranial aneurysms.

BACKGROUND: The treatment of very small (⩽3 mm) aneurysms is technically challenging. Mini-clips used for clipping these small aneurysms have a smaller closing force compared with standard clips. OBJECTIVE: To describe the double-clip technique for very small aneurysms. METHODS: The double-clip technique, a parallel duplication clipping technique of booster clipping, is used by the senior author for clipping very small aneurysms with morphology suitable for the application of 2 clips. The aneurysm is clipped after application of temporary clip(s), administration of adenosine, or both. An initial mini-clip is applied, leaving a small residual neck sufficient for application of the second mini-clip. A second mini-clip of the same size and shape is applied on the residual neck parallel to the initial clip. The initially applied mini-clip, which is in close contact with the second clip, supports the second clip and prevents its slippage. This technique was retrospectively reviewed over a 13-year period (1997-2009). There were 3246 patients with 4757 aneurysms treated in the same period. RESULTS: The outcomes of 39 patients with 40 very small aneurysms clipped with the double-clip technique were analyzed. None of the patients had technique-related complications. Postoperative angiograms revealed complete aneurysm occlusion of 39 aneurysms and a small residual neck in 1 aneurysm. No parent artery obstruction was observed in the postoperative angiogram. CONCLUSION: The double-clip technique is a safe and effective variation of booster clipping in the treatment of very small aneurysms with suitable morphology.

The anterior temporal approach for microsurgical thromboembolectomy of an acute proximal posterior cerebral artery occlusion.

BACKGROUND: In a short window of time, intravenous and intra-arterial thrombolysis is the first treatment option for patients with an acute ischemic stroke caused by the occlusion of one of the major brain vessels. Endovascular treatment techniques provide additional treatment options. In selected cases, high revascularization rates following microsurgical thromboembolectomy in the anterior circulation were reported. A technical note on successful thromboembolectomy of the proximal posterior cerebral artery has not yet been published. OBJECTIVE: To describe the technique of microsurgical thromboembolectomy of an acute proximal posterior cerebral artery occlusion and the brainstem perforators via the anterior temporal approach. METHODS: The authors present a technical report of a successful thromboembolectomy in the proximal posterior cerebral artery. The 64-year-old male patient had an acute partial P1 thromboembolic occlusion, with contraindications for intravenous recombinant tissue plasminogen activator. The patient underwent an urgent microsurgical thromboembolectomy after a frontotemporal craniotomy. RESULTS: The postoperative computerized tomography angiography showed complete recanalization of the P1 segment and its perforators, which were previously occluded. The early outcome after 1 month and 1 year follow-ups showed improvement from modified Rankin scale 4 to modified Rankin scale 1. CONCLUSION: Microsurgical thromboembolectomy can be an effective treatment option for proximal occlusion of the posterior cerebral artery in selected cases and experienced hands. Compared with endovascular treatment, direct visual control of brainstem perforators is possible. ABBREVIATIONS: ICG, indocyanine green mRS, modified Rankin scale P1, precommunicating segment of posterior cerebral artery PCA, posterior cerebral artery r-tPA, recombinant tissue plasminogen activator

Technical Description of the Medial and Lateral Anterior Temporal Approach for the Treatment of Complex Proximal Posterior Cerebral Artery Aneurysms.

BACKGROUND Posterior cerebral artery (PCA) aneurysms are often fusiform and associated with multiple intracranial aneurysms. A bypass procedure in combination with proximal occlusion or aneurysm trapping is considered to be effective for the treatment of patients with complex PCA aneurysms. Because of the deep, narrowed surgical corridor and the surrounding sensitive neuroanatomic structures, microsurgical procedures applied to the PCA are technically demanding. The authors present a technical report of a complex aneurysm formation located at the postcommunicating segment of the PCA (PCA-P2) treated via an anterior temporal approach. METHODS A 68-year-old woman had an unruptured PCA-P2 aneurysm formation, which was discovered incidentally. The fusiform aneurysm shape of the distal aneurysm aggravated direct microsurgical and endovascular treatment. After an individual case discussion, the patient underwent a microsurgical clipping of the proximal P2 segment aneurysm and the distal PCA-P2 segment aneurysm was treated by trapping after the application of a superficial temporal artery (STA) to PCA-P2 bypass using an anterior temporal approach. RESULTS Postoperative computed tomography angiography showed the exclusion of the proximal PCA-P2 aneurysm and an adequate flow from the STA to PCA-P2 bypass to the distal PCA segments. The patient showed a modified Rankin scale of 0 after follow-up at 1 and 3 months. CONCLUSIONS The anterior temporal approach is feasible for the microsurgical management of complex postcommunicating PCA aneurysms and the application of bypass procedures.

Microstructure analysis method for evaluating degenerated intervertebral disc tissue.

Degeneration of intervertebral disc (IVD) tissue is characterized by several structural changes that result in variations in disc physiology and loss of biomechanical function. The complex process of degeneration exhibits highly intercorrelated biomechanical, biochemical, and cellular interactions. There is currently some understanding of the cellular changes in degenerated intervertebral disc tissue, but microstructural changes and deterioration of the tissue matrix has previously been rarely explored. In this work, sequestered IVD tissue was successfully characterized using histology, light microscopy, and scanning electron microscopy (SEM) to quantitatively evaluate parameters of interest for intervertebral disc degeneration (IDD) such as delamination of the collagenous matrix, cell density, cell size, and extra cellular matrix (ECM) thickness. Additional qualitative parameters investigated included matrix fibration and irregularity, neovascularization of the IVD, granular inclusions in the matrix, and cell cluster formation. The results of this study corroborated several previously published findings, including those positively correlating female gender and IVD cell density, age and cell size, and female gender and ECM thickness. Additionally, an array of quantitative and qualitative investigations of IVD degeneration could be successfully evaluated using the given methodology, resin-embedded SEM in particular. SEM is especially practical for studying micromorphological changes in tissue, as other microscopy methods can cause artificial tissue damage due to the preparation method. Investigation of the microstructural changes occurring in degenerated tissue provides a greater understanding of the complex process of disc degeneration as a whole. Developing a more complete picture of the degenerative changes taking place in the intervertebral disc is crucial for the advancement and application of regenerative therapies based on the pathology of intervertebral disc degeneration.

Retrograde Suction Decompression for Clip Occlusion of Internal Carotid Artery Communicating Segment Aneurysms

BACKGROUND Retrograde suction decompression (RSD) can achieve proximal parent vessel control, improve aneurysm neck visualization, and allow parent vessel reconstruction for direct clipping of internal carotid artery (ICA) aneurysms. The aim of the present study was to describe the technique and surgical results of RSD for direct clipping of ICA communicating segment (C1) aneurysms. METHODS The clinical data and treatment summaries of 20 patients who underwent RSD-assisted clipping of ICA C1 aneurysms were retrospectively reviewed. Pre- and postoperative three- or four-dimensional computed tomography angiograms, postoperative magnetic resonance images, surgical notes, operative complications, and outcomes were assessed. RESULTS All patients except one harbored unruptured C1 aneurysms. Extracranial-intracranial graft bypass using the radial artery was performed in five patients. Fifteen patients required temporary clipping of the posterior communicating artery for further reduction of blood back-flow into the aneurysm. All aneurysms were successfully clipped and postoperative three- or four-dimensional computed tomography angiography revealed no major branch occlusion or residual aneurysm. At the 6-month follow-up examination, 19 patients had a good outcome and 1 patient had poor outcome associated with anterior choroidal artery ischemia. No death had occurred at 6-month follow-up examination. CONCLUSIONS The RSD technique is a useful procedure to achieve proximal vascular control, to soften and shrinkage the aneurysm sac, and to provide a wide and clean operative field allowing safe clip placement. The RSD technique requires special attention to the relationship between the perforators and the aneurysm, and close cooperation between the surgeon and the assistant.

Lateral supraorbital approach to ipsilateral PCA-P1 and ICA-PCoA aneurysms.

Background: Aneurysms of the posterior cerebral artery (PCA) are rare and often associated with anterior circulation aneurysms. The lateral supraorbital approach allows for a very fast and safe approach to the ipsilateral lesions Circle of Willis. A technical note on the successful clip occlusion of two aneurysms in the anterior and posterior Circle of Willis via this less invasive approach has not been published before. The objective of this technical note is to describe the simultaneous microsurgical clip occlusion of an ipsilateral PCA-P1 and an internal carotid artery - posterior communicating artery (ICA-PCoA) aneurysm via the lateral supraorbital approach. Case Description: The authors present a technical report of successful clip occlusions of ipsilateral located PCA-P1 and ICA-PCoA aneurysms. A 59-year-old female patient was diagnosed with a PCA-P1 and an ipsilateral ICA-PCoA aneurysm by computed tomography angiography (CTA) after an ischemic stroke secondary to a contralateral ICA dissection. The patient underwent microsurgical clipping after a lateral supraorbital craniotomy. The intraoperative indocyanine green (ICG) videoangiography and the postoperative CTA showed a complete occlusion of both aneurysms; the parent vessels (ICA and PCA) were patent. The patient presents postoperative no new neurologic deficit. Conclusion: The lateral supraorbital approach is suitable for the simultaneous microsurgical treatment of proximal anterior circulation and ipsilateral proximal PCA aneurysms. Compared to endovascular treatment, direct visual control of brainstem perforators is possible.

Long-Term Causes of Death and Excess Mortality After Carotid Artery Ligation.

OBJECTIVE Carotid artery ligation (CAL) is used to treat large and complex intracranial aneurysms. However, little is known about long-term survival and causes of death in patients who undergo the procedure. This study was intended to evaluate if patients who have undergone CAL have long-term excess mortality and what the causes of death are. METHODS All patients were treated at Helsinki University Hospital between 1937 and 2009. Patients who had undergone CAL and survived ≥1 year after the procedure were included in the cohort. Follow-up was until death or 2015 (2711 patient-years). Causes of death were reviewed and relative survival ratios calculated using the Ederer II method and a matched population. RESULTS There was 12% excess mortality in all patients 20 years after CAL and 22% after 30 years. A higher proportion of the patients who had subarachnoid hemorrhage (SAH) died during follow-up compared with unruptured patients undergoing CAL. Cardiovascular disease and cerebrovascular accident were the leading causes of death. CONCLUSIONS Patients with unruptured aneurysms did not experience as much excess mortality as those who had an SAH. The higher proportion of deaths observed in ruptured patients may be partly because of long-term excess mortality conferred by the SAH itself or SAH risk factors. Although the entire population did display excess mortality compared with the general population, this may be because of shared risk factors for aneurysm development and rupture and the cause of death.