Kristine Ravina

Assessment of Hemodynamic Changes and Hyperperfusion Risk After Extracranial-to-Intracranial Bypass Surgery Using Intraoperative Indocyanine Green–Based Flow Analysis

BACKGROUNDnIntraoperative blood flow assessments during cerebral bypass would ideally assess vessel patency, downstream perfusion, and risk of postoperative hyperperfusion syndrome (HPS). Previous studies using indocyanine green-based flow analyses (ICG-BFA) have identified multiple parameters that can intraoperatively track bypass-related changes in cerebral perfusion and potentially predict postoperative risk of HPS. Herein, we determine the most robust parameter and anatomic location for intraoperative ICG-BFA assessment of bypass-related perfusion changes and prediction of postoperative risk of HPS.nnnMETHODSnRetrospective analysis of an institutional review board-approved prospective database identified patients undergoing superficial temporal artery-to-middle cerebral artery bypass. Demographic and clinical information, as well as manually calculated and automated pre- and postbypass intraoperative ICG-BFA data from cortical, arterial, and venous regions of interest were recorded and analyzed.nnnRESULTSnSeven patients underwent superficial temporal artery-to-middle cerebral artery bypass (4 Moyamoya, 3xa0carotid occlusions). Average age was 48.2 ± 13.9 years (3xa0female, 4 male). Although all parameters measured showed trends toward improvement postbypass, only changes in arterial and venous automated ICG-BFA slope (also known as blood flow index [maximum intensity/rise time]) reached significance. None of the patients experienced symptomatic HPS, despite 5 of 7 (71.4%) having an increased HPS risk based on previously published ICG-BFA data.nnnCONCLUSIONSnICG-BFA has utility for the intraoperative assessment of bypass-related changes in cerebral perfusion, with automated blood flow index being the most robustly affected parameter. Although previously published ICG-BFA indices did not predict the development of symptomatic postoperative HPS, larger-scale studies correlating observed ICG-BFA changes with risk of HPS are warranted.

Running-to-Interrupted Microsuture Technique for Vascular Bypass

BACKGROUNDnThe ideal suturing technique for microvascular anastomosis for neurosurgical bypass procedures remains a point of debate. Simple interrupted sutures are thought to possess higher long-term patency but require more time to place as compared to running sutures.nnnOBJECTIVEnTo optimize the efficiency of microvascular anastomosis and limit brain ischemia time.nnnMETHODSnThe running-to-interrupted microsuture technique, a modification of the previously published spiral anastomosis, is described wherein loosely thrown running sutures are placed between 2 opposed anchor stitches. The loops are then serially cut and tied, resulting in efficiently placed interrupted stitches. This process is repeated on the opposite side to complete the anastomosis.nnnRESULTSnThe running-to-interrupted microsuture technique is quickly learned, limits unnecessary microsurgical movements, and is employed by the senior author for a multitude of cerebral arterial bypass procedures.nnnCONCLUSIONnThis technical improvement can be adapted by any neurovascular surgeon to optimize microsurgical efficiency and limit anastomosis-related brain ischemia times.

Transblepharo-Preseptal Modified Orbitozygomatic Craniotomy for Treatment of Ruptured Aneurysm: 3-Dimensional Operative Video

Various supraorbital approaches to the anterior cranial fossa using a transciliary or supraciliary incision have been described. An orbitotomy is a valuable addition to the standard supraorbital keyhole approach offering an extended angle of exposure with minimal frontal lobe retraction. The transpalpebral approach is common in oculoplastic surgery and offers excellent cosmetic outcomes using the natural crease of the superior eyelid. This approach avoids risk of eyebrow alopecia and damage to the frontalis muscle or frontalis branches of the facial nerve. A transblepharo-preseptal or transpalpebral modified orbitozygomatic approach for the treatment of unruptured anterior circulation aneurysms has been reported. Our experience with this approach has been that it has potential to offer anterior skull base access and outcomes that are not inferior to traditional approaches for selected cases including ruptured anterior circulation aneurysms. Moreover, we believe this approach can provide excellent cosmetic results and could minimize surgical time and hospitalization stay. This 3-dimensional video presents the case of a 47-year-old female with sudden-onset headache and seizure (Video 1). She was found to have a subarachnoid hemorrhage resulting from rupture of a carotid terminus aneurysm. Considering the location and morphology of the aneurysm, as well as the patients eyelid anatomy, clip ligation via a transblepharo-preseptal modified orbitozygomatic craniotomy was recommended. Aneurysm clipping was uneventful, and postoperative imaging showed complete occlusion. The patient was discharged neurologically intact.

Extracranial-Intracranial Bypass for Treatment of Blister Aneurysms: Efficacy and Analysis of Complications Compared with Alternative Treatment Strategies

OBJECTIVEnBlister aneurysms (BAs) represent a clinical challenge without a consensus treatment strategy. We report our institutions experience with BAs with an emphasis on the use of extracranial-to-intracranial (EC-IC) bypass.nnnMETHODSnSeventeen patients with BAs (88% [15/17] ruptured) were treated with microsurgical techniques (5 clip wrappings, 4 clip ligations, 4 EC-IC bypasses and clip trappings, 2 internal carotid artery ligations [1 combined with clip wrapping], and 2 clip trappings).nnnRESULTSnSix of 17 patients experienced intraoperative ruptures. There were no intraoperative ruptures among the bypass cases and 75% (3/4) of patients achieved a good neurologic outcome. Further, a literature review was performed to identify all previously reported cases of BAs undergoing clip ligation, clip wrapping, EC-IC bypass/clip trapping, and endovascular therapies, encompassing 246 BA cases across 33 studies. Intraoperative ruptures occurred in 29% of clip ligations (23/79), 27.2% of clip wrappings (6/35), 16.1% of EC-IC bypasses (5/31), and 0% of endovascular treatments. Aneurysm recurrence occurred in 2.97% (3/101) with endovascular therapies to 0% with EC-IC bypass. Mortality was 8.8% for clip ligation/wrapping (10/114), 6.5% for EC-IC bypass (2/31), and 4.0% for endovascular treatments (4/101).nnnCONCLUSIONSnEndovascular interventions have a favorable procedural safety profile but high rates of retreatment for persistent filling or posttreatment aneurysmal growth. Clip ligation and clip wrapping techniques have lower retreatment rates but slightly higher intraoperative risk. EC-IC bypass can safely provide definitive aneurysm securement and should be considered as a first-line therapy for BAs at high-volume bypass centers.

Transblepharo-Preseptal Modified Orbitozygomatic Approach for the Treatment of Ruptured Proximal Anterior Circulation Aneurysms

BACKGROUNDnMinimally invasive skull base approaches, including the cosmetically optimal transblepharo-preseptal modified orbitozygomatic (TBMOZ) technique, have been described to treat proximal anterior circulation aneurysms. The use of minimally invasive techniques for previously ruptured aneurysms is rare because of perceived technical challenges in controlling intraoperative ruptures. Herein, we determine the utility of the minimally invasive TBMOZ approach for the treatment of ruptured proximal anterior circulation aneurysms.nnnMETHODSnA retrospective analysis of an institutional review board-approved, prospective database was performed to identify patients with ruptured anterior circulation aneurysms treated with a TBMOZ approach. Patient demographics, aneurysm characteristics, temporary clip time, intra-operative ruptures, and neurologic outcomes were recorded.nnnRESULTSnFifteen patients (9 females, 6 males; average age, 53.6 ± 12.2 years) underwent a TBMOZ craniotomy following subarachnoid hemorrhage for clipping of 17 aneurysms (12 anterior communicating, 3 posterior communicating, and 2 carotid terminus). Four of 15 patients (26.6%) experienced intraoperative rupture, which was easily controlled in all patients and did not affect clinical outcomes. All patients had complete aneurysm ablation confirmed on postoperative cerebrovascular imaging. Good neurologic outcomes (Glasgow Outcome Score [GOS] of 5) were achieved in 73.3% (nxa0= 11) of patients at time of hospital discharge; the remaining patients had a GOS of 3-4. No patients experienced frontalis muscle weakness or facial nerve injuries, and all patients had acceptable cosmetic outcomes. One patient (6.6%) experienced a surgery-related complication: postoperative versus vasospasm-induced perforator infarcts.nnnCONCLUSIONSnThe TBMOZ approach provides a minimally invasive option for the safe treatment of previously ruptured proximal anterior circulation aneurysms.

Complete Cavernous Sinus Resection: An Analysis of Complications

BACKGROUNDnComplete cavernous sinus resection has been described for patients with malignant or recurrent cavernous sinus tumors without other therapeutic options but has been associated with high morbidity and mortality rates. We reviewed the complications associated with complete cavernous sinus resection to gain insights for future complication avoidance.nnnMETHODSnA retrospective analysis of a prospective, single-institution database was performed to identify patients who had undergone complete cavernous sinus resection from July 2014 to October 2017. Patient- and disease-specific data, surgical complications, and clinical outcomes were recorded.nnnRESULTSnTwo male patients underwent complete cavernous sinus resection (aged 60 and 47 years) for recurrent maxillary tumors with secondary cavernous sinus extension. Revascularization was performed based on balloon test occlusion (BTO) results, with extracranial-to-intracranial bypass performed in 1 patient with a concerning hemispheric flow pattern found during BTO. Vascularized free flaps were used in both patients to assist with closure of the resulting skull base defect. Three complications related to surgery occurred in 1 patient (thigh hematoma, recurrent cerebrospinal fluid leak, and meningitis). One patient died of pneumonia approximately 2 weeks postoperatively, and the other experienced an acceptable neurologic and oncologic outcome.nnnCONCLUSIONSnDespite the high peri- and postoperative risks, complete cavernous sinus resection can be considered for select patients with tumors involving the cavernous sinus without other treatment options. Familiarity with cerebral bypass and free flap reconstruction of skull base defects is critical for complication avoidance and management.

Multiple Intracranial Aneurysms from Coccidioidal Meningitis: A Case Report Featuring Aneurysm Formation and Spontaneous Thrombosis with Literature Review

BACKGROUNDnCoccidioidal meningitis can progress to vasculitis with aneurysm formation. Although aneurysmogenesis is rare, it carries exceptionally high mortality. Except in one instance, prior case reports have documented universally fatal consequences.nnnCASE DESCRIPTIONnA 26-year-old man developed disseminated coccidioidomycosis with formation of multiple aneurysms throughout the anterior intracranial vasculature bilaterally. This report is unique in that it chronicles the formation and subsequent spontaneous thrombosis of several aneurysms over a 4-week period. In total 10 aneurysms were documented in the same patient-the highest reported to date. The patient was eventually discharged from the hospital for what has heretofore been a universally fatal disease process. Neurologic examination and vascular imaging 1 month after discharge demonstrated stable findings.nnnCONCLUSIONSnCoccidioidal aneurysms carry a high mortality. The mainstay of therapy remains lifelong triazole antifungal therapy with the addition of liposomal amphotericin in cases of treatment failure. Steroid use is controversial but should be considered whenever there is vascular involvement. Although watchful waiting is reasonable in light of the possibility of spontaneous thrombosis with medical management, dynamic changes in aneurysm size or configuration should prompt timely endovascular or operative interventions.

Revision Microvascular Decompression for Trigeminal Neuralgia and Hemifacial Spasm: Factors Associated with Surgical Failure

Objective To investigate risk factors for symptom recurrence in patients requiring a revision microvascular decompression (MVD) for trigeminal neuralgia (TN) or hemifacial spasm (HFS). Design Retrospective review of a prospectively maintained database. Participants Seventeen consecutive patients undergoing revision MVD at our institution between January 1993 and September 2017. Main Outcome Measures The incidence and causes for revision MVDs were recorded. Response to revision MVD for TN was tracked using the Barrow Neurological Institute (BNI) grading scale. Response to revision MVD for HFS was graded as “no improvement,” “some relief,” or “complete resolution” of symptoms. Results Revision MVD rate for the senior author across all MVDs performed in this period was 1.9% for TN and 9.3% for HFS. Initial MVD failure was primarily caused by active inflammation and/or scarring and adhesions in 5/17 patients, malposition/slippage of Teflon in 3/17 patients, and insufficient Teflon in 1/17 patients. Without other factors, a new site of neurovascular conflict was identified in 4/17 patients, while the same site of neurovascular conflict was found in 3/17 patients. No cause could be identified in 1/17 patients. Scarring was found primarily in the TN group and was associated with symptom persistence. Conclusion Revision MVD for recurrent TN and HFS is an effective procedure offering the prospect of a complete cure. Proper Teflon use is crucial for surgical success. Scarring after initial MVD is a negative prognostic factor requiring destructive treatment consideration. Although morbidity rates were slightly increased with revision versus original MVDs, the complications were non‐disabling and resolved over time.

Occipital Artery to Posterior Cerebral Artery Bypass Using Descending Branch of the Lateral Circumflex Femoral Artery Graft for Treatment of Fusiform, Unruptured Posterior Cerebral Artery Aneurysm: 3-Dimensional Operative Video

Posterior cerebral artery (PCA) aneurysms can be technically challenging lesions due to the intricacy of perforating branches and the relationship to cranial nerves and the brainstem. Fusiform aneurysms of the perimesencephalic segment of the PCA are a rare finding which does not favor direct clip occlusion or reconstruction. In such cases, proximal parent vessel occlusion is an option for aneurysm treatment. Extracranial-intracranial (EC-IC) bypass can be used to revascularize beyond the lesion when considering proximal occlusion. Based on previous literature for occipital artery (OA) bypass and the time-consuming dissection required for OA harvest, an interposition graft was chosen. The descending branch of the lateral circumflex femoral artery (DLCFA) is a good alternative interposition graft with a diameter that is favorable for revascularizing smaller, more distal vessels.This 3-dimensional video presents the case of a 26-year-old female with severe headaches who was found to have unruptured, fusiform aneurysmal dilatations of the PCA. Given the patients youth and the morphology of the aneurysms, an EC-IC bypass with proximal occlusion was recommended. The DLCFA was used as an interposition graft. The left OA was found to be a suitable donor. A subtemporal approach was used to access the PCA for proximal occlusion. An occipital interhemispheric approach was performed to isolate a suitable recipient segment of the ipsilateral PCA branch for microvascular end-to-side anastomosis. Postoperative catheter angiography showed significant thrombosis of the fusiform aneurysms and a patent EC-IC bypass. Postoperative magnetic resonance imaging showed no infarcts and the patient was discharged neurologically intact.The patient was consented for inclusion in a prospective institutional review board (IRB) approved database from which this IRB approved retrospective report was performed. The consent for intraoperative video and picture use was also obtained.Images in the video between 0:49 and 1:11,

Intraoperative Assessment of Cortical Perfusion After Intracranial-To-Intracranial and Extracranial-To-Intracranial Bypass for Complex Cerebral Aneurysms Using Flow 800

BACKGROUNDnRevascularization strategies for complex cerebral aneurysms are largely based on subjective interpretation of flow demands, or indirect measures of perfusion in at-risk territories. Indocyanine Green -based flow analyses ((ICG-BFA); Flow 800, Carl Zeiss, Oberkochen, Germany) provide a real-time, semiquantitative measure of intraoperative cortical perfusion during cerebral bypass surgery for complex aneurysms.nnnOBJECTIVEnTo determine the utility of intraoperative ICG-BFA for assessing cortical perfusion in at-risk territories during cerebral bypass for complex aneurysms requiring vessel sacrifice.nnnMETHODSnRetrospective analysis of consecutive patients from a prospective, single-institution open cerebrovascular database.nnnRESULTSnIntraoperative ICG-BFA confirmed adequate cortical perfusion in 2 patients with fusiform posterior circulation aneurysms, treated with a posterior inferior cerebellar artery (PICA)-PICA and occipital artery (OA)-to-third segment of the posterior cerebral artery (P3) bypass with proximal vessel sacrifice, respectively. ICG-BFA was used in a third patient that underwent clip reconstruction/ intracranial-to-intracranial bypass for a large middle cerebral artery (MCA) bifurcation aneurysm requiring sacrifice of the temporal M2 branch. In this case, a frontal M3 to temporal M3 side-to-side anastomosis was created to arborize the MCA tree and allow filling of both M2 territories through a single M2 branch. After aneurysm reconstruction, ICG-BFA identified an inadvertent occlusion of the frontal M2 that left the entire MCA distribution reliant on collateral flow but did not cause a neuromonitoring change. Repeat ICG-BFA after clip re-arrangement demonstrated aneurysm occlusion and equal flow in both frontal and temporal MCA cortical distributions from the arborization.nnnCONCLUSIONnICG-BFA is a useful adjunct for intraoperative cortical flow assessment during cerebral revascularization for complex aneurysms requiring vessel sacrifice.