Microsurgical thrombectomy: where the ancient art meets the new era.

Mechanical thrombectomy (MT) is the leading treatment for acute large vessel occlusion (LVO). However, surgical thrombectomy (ST) may have a role in well selected LVO patients where MT failed to re-establish flow, the endovascular route is inaccessible, or where MT is a financially prohibitive or absent option (developing and poor countries). We compared the efficacy and efficiency between ST and MT, and described our operative experience and its potential application in the developing world. Clinical outcomes, procedural times, and efficacy of treatment were compared between the MT and ST of acute LVO between 2012 and 2022. Propensity score-matched analysis was also conducted to compare MT and ST. One-hundred nine patients fulfilled the study criteria (77 MTs vs 32 STs). Factors driving outcome were age (aOR: 0.95, 95%CI, 0.91-0.98), hemisphere side (aOR: 0.38, 95%CI, 0.15-0.96), and DWI-ASPECT (aOR: 1.39, 95%CI, 1.09-1.77) at presentation by the multivariate analysis. Times from door-start of procedure (P = 0.45) and start of procedure-recanalization (P = 0.13) were similar between treatment options. Propensity score-matched analysis found no significant difference for 2 treatment methods about time of door to recanalization (P = 0.155) and outcome (P = 0.221). The prognosticators of thrombectomy for acute LVO in patients with successful recanalization were age, affected hemisphere side, and DWI-ASPECT score. Our evidence shows that the efficacy of ST is similar to that of MT. There should be a place of ST for cases of mechanical failure or tandem cervical ICA and MCA occlusion. ST may be a temporizing LVO treatment option in healthcare systems where MT is inexistent or financially prohibitive to patients.

Aberrant drainage of posterior condylar emissary vein and abnormal orifice of hypoglossal canal: surgical implications in the transcondylar fossa approach for VA-PICA junction aneurysm.

BACKGROUND: The posterior condylar emissary vein (PCEV) and posterior condylar canal (PCC) are anatomical landmarks for identifying important structures like jugular tubercle and occipital condyle in surgical approach to the foramen magnum and condylar fossa. Several anatomical variations have been described. Drainage into the jugular bulb is found to be commonest. METHOD: A 70-year-old patient with unruptured vertebral artery-posterior inferior cerebellar artery (PICA) junction aneurysm-underwent surgical clipping via transcondylar fossa approach. RESULT: Preoperative computed tomography demonstrated an abnormal communication existed between the left-sided PCC and hypoglossal canal (HC). The PCEV was identified draining into a dilated venous channel/pouch at the "hip" of sigmoid sinus (junction of sigmoid sinus and jugular bulb). Intra-operatively, an occipital artery-PICA bypass was performed. The PCEV was skeletonized, coagulated, and divided to achieve hemostasis. The lateral and cranial drilling around PCC was successful at safeguarding the underlying contents of HC (in medial and caudal extent). CONCLUSION: Preoperative angiography and detailed morphometric analysis of the PCC were helpful in planning surgical approach-identifying and controlling the PCEV, and skeletonization of the PCC without compromising the hypoglossal nerve and anterior condylar emissary vein.

Differences Between Subarachnoid Hemorrhage Seen in Daily Practice and Aneurysms That Rupture During Follow-Up.

[Figure: see text].

Outcome of retreatment for recurrent saccular cerebral aneurysms: a propensity score-matched analysis.

Although endovascular or surgical treatment has been performed for preventing the rupture of saccular cerebral aneurysms (sCA), in some patients, the aneurysms may recur and require retreatment. We aimed to investigate the clinical and radiological outcomes of treating recurrent sCA. We retrospectively evaluated the data of 52 patients with 60 recurrent sCAs who were retreated and 1534 patients with 1817 sCAs who received initial treatment. The primary outcome was a recurrence of the aneurysm. Secondary outcomes were an additional treatment, rupture after treatment, and a neurological worsening, which was defined as an increase of 1 or more scores using the modified Rankin Scale at 12-month. Safety outcomes included postoperative ischemic and hemorrhagic complications. We compiled the 120 (60 each) propensity score-matched cohort based on a propensity score for the treatment of recurrent sCA. In the propensity score-matched cohort, recurrence after treatment was observed in 25% and 6.7% of cases in the retreatment and initial treatment groups, respectively. The odds ratio of recurrence after treatment was 4.7 (95% CI, 1.4-15; P = 0.011). The secondary and safety outcomes were not significantly different between the two groups. This study showed that the treatment of recurrent sCA was a risk factor for recurrence after treatment but not for additional treatment, rupture after treatment, or neurological worsening. Although decision-making regarding the treatment varies depending on the institutional protocols and personal experience of the physicians, endovascular or surgical retreatment could be performed without hesitation.

Microsurgery of residual or recurrent complex intracranial aneurysms after coil embolization - a quest for the ultimate therapy.

The long-term stability of coil embolization (CE) of complex intracranial aneurysms (CIAs) is fraught with high rates of recanalization. Surgery of precoiled CIAs, however, deviates from a common straightforward procedure, demanding sophisticated strategies. To shed light on the scope and limitations of microsurgical re-treatment, we present our experiences with precoiled CIAs. We retrospectively analysed a consecutive series of 12 patients with precoiled CIAs treated microsurgically over a 5-year period, and provide a critical juxtaposition with the literature. Five aneurysms were located in the posterior circulation, 8 were large-giant sized, 5 were calcified/thrombosed. One presented as a dissecting-fusiform aneurysm, 9 ranked among wide neck aneurysms. Eight lesions were excluded by neck clipping (5 necessitating coil extraction); 1 requiring adjunct CE. The dissecting-fusiform aneurysm was resected with reconstruction of the parent artery using a radial artery graft. Three lesions were treated with flow alteration (parent artery occlusion under bypass protection). Mean interval coiling-surgery was 4.6 years (range 0.5-12 years). Overall, 10 aneurysms were successfully excluded; 2 lesions treated with flow alteration displayed partial thrombosis, progressing over time. Outcome was good in 8 and poor in 4 patients (2 experiencing delayed neurological morbidity), and mean follow-up was 24.3 months. No mortality was encountered. Microsurgery as a last resort for precoiled CIAs can provide-in a majority of cases-a definitive therapy with good outcome. Since repeat coiling increases the complexity of later surgical treatment, we recommend for this subgroup of aneurysms a critical evaluation of CE as an option for re-treatment.

[Combined Bypass and Cerebral Aneurysm Surgery:How to Choose and Practice?]

The treatment for cerebral aneurysms has been changing along with the advancements in endovascular treatment. In particular, the induction of a flow-diverter stent can treat even cavernous portion aneurysms, which have been difficult to treat without parent artery occlusion. The definite advantages of the open surgery are low recurrence rates, high angiographic outcome, and bypass. Herein, we describe the bypass method for treating cerebral aneurysms. The purpose of the bypass, difference between high-flow and low-flow bypasses, how to select the donor artery, and variation of bypass technique are described.

Surgical treatment of unruptured distal basilar artery aneurysm: durability and risk factors for neurological worsening.

BACKGROUND: Distal basilar artery aneurysms (DBAs) consist of basilar apex and basilar artery-superior cerebellar artery bifurcation (BA-SCA) aneurysms. The authors aimed to investigate clinical and radiological differences between two locations and to evaluate the 12-month surgical outcome in unruptured DBAs. METHODS: Fifty-six consecutive patients who underwent surgical treatment (37 basilar apex and 19 BA-SCA aneurysms) between April 2012 and February 2016 were retrospectively evaluated. In patients with a preoperative modified Rankin Scale score (mRS) of more than 1, neurological worsening (NW) was defined as an increase in one or more mRS. In patients without symptoms, NW was defined as mRS ≥2. RESULTS: The mean age of the patient population was 64 ± 9.6 years, and 48 (86%) were female. Mean follow-up period was 2.6 ± 0.94 years. An excellent (mRS 0 to 1) outcome was archived in 31 (55%), 45 (82%), and 48 (87%) patients at 30 days, 6 months, and 12 months, respectively. Clinical and radiological characteristics showed no differences between two locations. One early death (1.8%) and one severe morbidity (1.8%) due to rupture were observed. The postoperative annual rupture rate was 1.4% overall (145 patient-years). After adjustment for age and location, large or giant DBA was related to 30-day and 12-month NW [n = 22 (39%) and n = 6 (11%); p = 0.009 and 0.002, respectively], aneurysm localization in the interpeduncular cistern (LIC) and perforator territory infarction were related to 30-day NW (p = 0.002 and 0.002), and DBA that needed bypass surgery and previously treated recurrent DBA were related to NW at 12 months (p = 0.017 and 0.001). Multivariate analysis showed that LIC was significantly related to perforator territory infarction (p = 0.003). CONCLUSIONS: Clinical and radiological characteristics were not different between basilar apex and BA-SCA aneurysms; therefore, they should not be discussed separately. To avoid neurological worsening, results of surgical treatment for unruptured DBAs should be improved.

Combined Direct and Indirect Revascularisation With Superficial Sparing of Temporalis Muscle in Moyamoya Disease: Operative Technique: 2-Dimensional Operative Video.

The primary objective of revascularization surgery for moyamoya disease (MMD) is to augment cerebral blood flow and prevent disease progression.1 There are several options for bypass surgery, including direct methods such as superficial temporal artery-middle cerebral artery anastomosis, indirect bypasses such as encephalomyosynangiosis, encephaloduroarteriosynangiosis or encephaloduroarteriomyosynangiosis, or combined procedures.2-5 In our institution, we undertake a combined approach involving multiple low-flow bypasses and a modified indirect bypass technique, with additional attention to achieving an optimal cosmetic result. Given that MMD often affects young patients, considering cosmesis as a significant factor in managing this condition should be standard practice. We present our modified operative technique of a combined approach to revascularization surgery in patients with MMD with particular emphasis on the indirect bypass procedure. The temporalis muscle is divided in two parts in the sagittal plane where the deeper portion is mobilized to perform an EMS, and the superficial portion is reattached to the bone flap to maintain cosmetic symmetry. A 23-year-old woman presented with a 6-month history of transient left-sided hemiparesis on a background of MMD (previous left-sided revascularization surgery). Subsequent imaging demonstrated worsening right internal carotid artery stenosis. The patient and her family were extensively counseled and decision to proceed with right-sided bypass surgery was undertaken (Video). The patient had an unremarkable postoperative course and was discharged home on day 14. Institutional review board approval was not required in our institution. The patient consented to the procedure and to the publication of his/her images.

Basal vein of Rosenthal classification: the key to venous outflow of the deep sylvian fissure.

OBJECTIVE: Mastery of sylvian fissure dissection is essential to access lesions within the deep basal cisterns. The deep sylvian vein and its tributaries play a major role during access to and beyond the carotid cistern through the sylvian fissure and determine the complexity of microdissection. Preserving the venous outflow during sylvian fissure dissection is the best reliable strategy to prevent postoperative venous strokes or venous hypertension. The authors report the role of the basal vein of Rosenthal (BVR) in the venous outflow pattern of the deep sylvian cistern. METHODS: The authors analyzed 262 consecutive surgical cases involving sylvian fissure dissection from 2015 to 2017. Inclusion criteria were complete sylvian fissure dissection for the treatment of intracranial aneurysms. Exclusion criteria were giant size (aneurysm diameter > 24 mm), meningitis, subarachnoid hemorrhage within the sylvian cistern, absence of 4D CT angiography, and previous surgery. Retrospective radiological and operative video reviews were carried out to assess the association between the superficial sylvian vein and the BVR. The authors analyzed the course of the BVR and the patterns of venous drainage of the sylvian cistern. The surgical difficulty of sylvian fissure dissection was rated by the authors to study the operative significance of the venous patterns encountered. Two clinical cases are described to illustrate the proposed BVR classification. RESULTS: A total of 97 patients met the selection criteria. The most frequent type of BVR was immature (diameter < 0.5 mm, 68%). When the BVR was incompletely developed or absent (immature type), the deep sylvian veins drained through a middle sylvian vein in 70% of cases, requiring advanced sylvian fissure dissection techniques. However, when the BVR was completely developed (32%), the middle sylvian vein was found in a minority of cases (6%), which allowed for an unobstructed transsylvian corridor. Interrater and test-retest reliability of the surgical difficulty was greater than 0.9. CONCLUSIONS: Preoperative assessment of the BVR anatomy is key to predict the deep sylvian venous pattern. The authors provide objective evidence supporting the reciprocal relationship between the type of BVR and the presence of a middle sylvian vein and the deep sylvian venous outflow. An immature BVR should alert the neurosurgeon of the high likelihood of finding a complex deep venous pattern, which may drive surgical planning.

Case Report of Ruptured Large Fusiform Distal Anterior Cerebral Artery Aneurysm Treated With A3-A3 In Situ Bypass, Reimplantation, and Trapping With Aneurysmectomy: 2-Dimensional Operative Video.

Large fusiform aneurysms in the distal anterior cerebral territory are infrequent and pose considerable treatment challenges, as they necessitate comprehensive aneurysm resolution without compromising physiological flow dynamics.1-3 We present the case of a 52-year-old man with a ruptured distal anterior cerebral artery fusiform aneurysm. The patient consented to the procedure; this complex condition was successfully managed through an A3-A3 in situ bypass, branch reconstruction, and trapping accompanied by aneurysmectomy. The multifaceted nature of fusiform lesions precludes the feasibility of endovascular interventions as a sole remedy. In addition, reconstructive and deconstructive approaches exhibit elevated mortality rates in patients experiencing high-grade subarachnoid hemorrhage.1,4 Given the intricacies intrinsic to this clinical context and the exigent nature of fusiform aneurysms, the surgical therapeutic arsenal embraces a diverse array of surgical methodologies, each offering a bespoke spectrum of techniques meticulously tailored to attain predefined objectives.3,5-7 These approaches are attuned to promptly abrogate imminent threats, while concurrently mitigating latent complications linked to subarachnoid hemorrhage ensuing from aneurysmal rupture, encompassing the specters of rebleeding, ischemic stroke, and edematous sequelae.8,9 Crucially, the selection of the most appropriate surgical approach hinges on a comprehensive understanding of available options, patient-specific anatomic considerations, and the preferences of the neurosurgeon. Such a nuanced decision-making process ensures an individualized treatment strategy tailored to optimize patient outcomes.3,6.

Optimizing the Approach to STA-MCA Bypass Surgery and Reducing Wound Complications.

BACKGROUND AND OBJECTIVES: The treatment of complex intracranial aneurysms with bypass surgery using 2 branches of the superficial temporal artery (STA) proves to be an effective surgical option. However, the harvest of these 2 STA branches, combined with a pterional craniotomy, carries the potential risk of delayed wound healing of the skin flap. This study undertook a retrospective analysis to examine and identify the factors associated with this delayed wound healing. METHODS: A total of 56 consecutive cases, including both ruptured and unruptured complex intracranial aneurysms, that underwent bypass surgery with 2 branches of the STA, were analyzed retrospectively. RESULTS: Major delayed wound healing was observed in 6 (10.7%) cases. Univariate analysis demonstrated significant associations with the following factors: rupture (P = 0.023), presence of diabetes mellitus (P = 0.028), large craniotomy size (P = 0.012), and the type of skin incision (P ≤ 0.001). Age (P = 0.283), sex (P = 0.558), body mass index (P = 0.221), and other blood test parameters did not demonstrate any statistical significance. Similarly, the presence of a dominant frontal branch (P = 0.515) or a low-positioned frontal branch (P = 0.622) did not reveal statistically significant results. CONCLUSIONS: In the treatment of complex intracranial aneurysms, where harvesting of the 2 STA branches is involved with a pterional craniotomy, producing a smaller skin flap (L- or T-shaped incision) is effective in minimizing the risk of delayed wound healing. The process of harvesting the STA and closing the wound demands meticulous care, taking into consideration the normal anatomical structures and the subdermal vascular plexus of the scalp.

Bypass Surgery for Vertebral Artery and Posterior Inferior Cerebellar Artery Fusiform Aneurysms: Surgical Technique and Key Lessons.

Fusiform vertebral artery (VA) aneurysms are challenging to treat due to their pathophysiology, morphology, and anatomic location.1,2 Endovascular treatments are considered to be a widely adopted safe option for this pathology.1 Open microsurgical treatment is considered for complex anatomy, important branch involvement, poor collateral flow, or failed endovascular therapy.3-7 This report aims to show the flow-replacement strategy and bypass technique for a VA aneurysm with complex anatomy and branch involvement. A 24-year-old man presented to our clinic with a bilateral fusiform VA aneurysm discovered during workup of progressive headaches. Further investigation revealed that the left-side aneurysm was mostly thrombosed and the posterior inferior cerebellar artery arose from the aneurysm dome with a fusiform enlargement within a few millimeters from the branching point. After evaluating all management options, the patient decided on surgical treatment of the left VA aneurysm. We performed an occipital artery to posterior inferior cerebellar artery end-to-side anastomosis distal to the fusiform enlargement, followed by trapping of the aneurysm and dome resection (Video 1). Antegrade flow to the distal VA was reestablished using a radial artery interposition graft, thus preventing any flow alterations that may cause growth or rupture of the contralateral aneurysm caused by increased hemodynamic stress if the ipsilateral VA flow is not preserved.8 After in-hospital physical rehabilitation, the patient was discharged with a modified Rankin Scale score of 1. The contralateral aneurysm is managed with serial imaging and treatment will ensue if there is clinical-radiologic evolution. The patient consented to the procedure and publication of his image.

A Practical Guide to Train the Side-to-side Anastomosis: Tips, Tricks and Technical Nuances.

BACKGROUND: Microanastomosis presents a challenge in neurosurgical procedures, requiring specialized skills. Regular practice outside the operating room is crucial. This study aims to provide a detailed description of the side-to-side anastomosis technique and analyze its advantages in preventing failures compared with other variations. METHODS: We examined the technique, characteristics, and outcomes of side-to-side bypass procedures for complex aneurysms in the anterior cerebral artery territory at our institution over the past decade. We compared our technique with those described in the literature by other groups. RESULTS: The Far East Neurosurgical Institute (FENI) technique was used in 15 patients, with 17 side-to-side anastomoses performed. The average anastomosis time was 27.5 minutes, with 100% patency in follow-up. Our technique demonstrated safety and effectiveness in treating intracranial aneurysms, yielding satisfactory short- and long-term functionality outcomes. We highlight the importance of maintaining a curvilinear arteriotomy shape, at least 3 times the diameter of the artery, and utilizing an interrupted suturing technique on the anterior wall. CONCLUSIONS: This paper presents the first comprehensive description of the side-to-side anastomosis technique, supported with images and videos for training and replicability. Our technique enhances flow dynamics and reduces the risk of acute thrombus formation. Training in simulators and microsurgery practice centers outside the operating room is essential for acquiring and refining microsurgical skills.

Training in Sylvian Arachnoid Dissection: The Art of Using Kamiyama Scissors and a Simple Novel Model for Practice Sylvian Arachnoid Dissection Using Cotton Fiber with Brain Model.

Background Transsylvian approach is one of the main approaches for a variety of vascular, tumor, and skull-base lesions. Sylvian fissure harbors a lot of critical structures including the middle cerebral artery and many venous structures. If not done properly, the transsylvian approach could cause several complications. Up to now, there is no simple training model for practicing Sylvian fissure dissection. In this article, we describe the technique of using microscissors for the sharp dissection of arachnoid trabeculae. We also propose a new model for practicing Sylvian arachnoid dissection using a three-dimensional (3D) brain model with cotton fiber. Materials and Method We inserted cotton fiber into the Sylvian fissure of the brain model (aneurysm box from UpsurgeOn) and covered the Sylvian fissure with a cotton sheet, then sprayed the water over it. We dissected this model under a microscope by using Kamiyama scissors in the right hand and suction in the left hand. Result Under the microscope, our model appears comparable with the real Sylvian fissure. We can use this model for practicing arachnoid dissection with Kamiyama scissors. Conclusion The arachnoid dissection model by using a 3D brain model with cotton fiber is a simplified and novel approach for practicing the Sylvian fissure dissection.

Reconstruction of intracranial vertebral artery with radial artery and occipital artery grafts for fusiform intracranial vertebral aneurysm not amenable to endovascular treatment: technical note.

BACKGROUND: Symptomatic fusiform intracranial vertebral artery aneurysms pose a formidable treatment challenge when not amenable to endovascular treatment. In this paper, we illustrate the microsurgical management of such an aneurysm. METHODS: To prevent neurological deterioration, anatomical reconstruction preserving all vessels including posterior inferior cerebellar artery and perforators is essential. In this case illustration, the occipital artery was used as a donor to a perforator originating from the aneurysmal segment. This bypass was performed in an end-to-side fashion. Subsequently, the aneurysmal component of the vertebral artery was resected and an end-to-side (V4 to V3) bypass was performed using a radial artery graft. RESULTS: The patient achieved complete resection of the aneurysm preserving normal anatomy of the posterior circulation without any ischemic complications. CONCLUSIONS: Complex cerebral artery bypass techniques are essential in the armamentarium of cerebrovascular for the treatment of complex lesions not amenable to endovascular therapy.

[The limits and countermeasures of the anterior temporal approach for unruptured upper basilar artery aneurysms].

BACKGROUND AND PURPOSE: In general, upper basilar artery aneurysms are treated following the transsylvian or subtemporal approach. These approaches have both advantages and disadvantages. Therefore, we followed the anterior temporal approach that provides a wider surgical field in the retro-carotid space. METHODS: We reviewed the clinical records of 37 patients with an upper basilar artery aneurysm operated on following the anterior temporal approach between 2002 and 2012 in our institute, and evaluated the usefulness of this approach. RESULTS: In 23 cases, several additional techniques were performed. In all these cases a wide operation field was obtained in the retro-carotid space and the aneurysm was completely obliterated. The post operative adverse events were temporary oculomotor palsy in 6 cases, permanent oculomotor palsy in 3 and temporary epilepsy, aphasia due to venous infarction and asymptomatic cerebral infarction in 1 case each. CONCLUSIONS: The anterior temporal approach allows the additional use of several techniques and provides a wide surgical field. Therefore, we consider this approach is useful to reach and treat upper basilar artery aneurysms.

High-Flow Bypass and Trapping of a Ruptured Internal Carotid Artery Blister Aneurysm: Operative Principles and Key Lessons.

Blood blister-like aneurysms (BBAs) are infrequent but challenging small aneurysms with fragile domes consisting of a thin adventitia layer.1 Flow diversion and microsurgical trapping are acceptable treatment options. While endovascular treatment is becoming the first choice in developed countries, it is prohibitive in most developing countries, where microsurgical treatment is the only feasible option. Microsurgical treatment offers superior obliteration rates at similar neurologic outcomes than endovascular treatment.1-3 Mastering high-flow revascularization and pressure monitoring is necessary to improve outcomes of BBA, especially in the developing world. We present our operative principles, which involve pressure monitoring and a high-flow bypass to ensure sufficient post-trapping cerebral pressure.4 A 53-year-old lady was found to have a modified Fisher 4 subarachnoid hemorrhage after the worst headache of her life. Endovascular flow diversion and trapping and bypass were discussed with the patient and family. A right internal carotid artery BBA was trapped (Video 1). A right superficial temporal artery to M4 middle cerebral artery (MCA) bypass was used to both maintain perfusion during a high-flow bypass and to measure cerebral blood pressure. An external carotid artery to MCA bypass using a saphenous vein graft provided >80% of baseline MCA arterial pressure, which prevents delayed ischemic strokes.4 The patient tolerated the procedure well and was discharged home without deficits on postoperative day 15 after vasospasm watch. The patient consented to the procedure and provided consent to the publication of her images.

"Microcisternal Drainage" Technique for Clipping a Middle Cerebral Artery Aneurysm.

Arachnoid dissection is often challenging because of tight corridors, microvasculature crossing the membranes, and a narrow operative field.1-4 It is often said that "splitting" the sylvian fissure measures the talent of a cerebrovascular neurosurgeon, and there are as many styles of sylvian fissure dissection as neurosurgical schools.4-8 Our principle is to dissect the subarachnoid space sharply and with minimal trauma to neither the microvasculature nor the pia matter.4,7-10 We have developed a technique that allows efficient and safe sharp dissection through the subarachnoid space: the "microcisternal drainage" technique. This technique (Video 1) consists of applying a pledget to a narrow cistern and suctioning the cerebrospinal fluid while maintaining uplifting retraction with the suction shaft. Clear trabeculae are dissected sharply to release microvessels at the convexity of their turns. This technique is especially advantageous when cisterns are narrow (e.g., pia-to-pia) or highly eloquent structures are at risk. The main advantages over conventional cisternal dissection are avoidance of refractive effect, enhanced identification of the microvasculature from the trabeculae, and preservation of pia matter. Using the microcisternal drainage technique, the microvasculature, arachnoid membranes, and pia reveal themselves, and we avoid the cerebrospinal fluid-related refractive effect, therefore maximizing depth perception. We report an example of the "microcisternal drainage" technique to split the sylvian fissure during treatment of an irregular middle cerebral artery bifurcation aneurysm on a 56-year-old woman. The patient tolerated the procedure well, was discharged without neurologic deficits, and resumed normal life with no aneurysm remnant. The patient consented to the procedure and video and photography publication.

The Microcisternal Drainage Technique.

BACKGROUND: Microsurgical dissection of arachnoid cisterns requires a combination of anatomic knowledge and microsurgical skill. The latter relies on experience and microsurgical dexterity, which depend on visual identification of cisternal microvasculature. We describe a novel standardized operative sequence to allow for bloodless arachnoid dissection when cisternal anatomy is challenging. METHODS: We used the reported technique in 1928 cases over the past 5 years (2018-2022). The outer arachnoid was incised to enter the cisternal space. A cotton pledget was placed in contact with an inner membrane and gently pushed laterally and superficially with the suction cannula at medium suction power. When the arachnoid membranes dried, arachnoid trabeculae were cut and microvasculature were released at the convexity of their loops and gently transposed off the dissection trajectory. The same principle was used to release parent and perforating arteries from the aneurysm dome. RESULTS: The microcisternal drainage technique enabled safe and efficient access through adhered arachnoid in all cases. A complex anterior communicating artery aneurysm in a 52-year-old lady demonstrated the use of the microcisternal drainage technique during access through the pericallosal cistern. This technique was used in all cases where cisternal dissection was needed. CONCLUSIONS: The microcisternal drainage technique uses deliberate and strategic suction, dynamic retraction, and nuanced scissor cuts to enable precise and bloodless microdissection of adherent arachnoid cisterns. This technique combines common neurosurgical maneuvers in a novel standardized sequence to improve efficiency and safety during arachnoid dissection.

Reverse Suction Decompression Using the Superior Thyroid Artery During Clipping of a Complex Anterior Choroidal Artery Aneurysm.

Direct aneurysmal suction decompression was first described by Dr. Flamm in 1981 to improve safety and ease clipping of complex aneurysms by deflating their dome.1 This technique evolved over the following decade, from direct aneurysmal puncture to indirect-reverse-suction decompression (RSD).2,3 The conventional technique for RSD involves a cannulation of the internal (ICA) or common (CCA) carotid arteries.2-9 Direct puncture of either the CCA or ICA carry risk of arterial wall damage (e.g., dissection), which may result in significant morbidity.10,11 We routinely cannulate the superior thyroidal artery (SThA) as the vascular access to perform RSD. This subtle technical nuance prevents dissection of either the CCA or ICA while providing a reliable source for RSD.12 In this operative video, the SThA was cannulated to apply reverse suction decompression, which allowed releasing perforating arteries from the dome of an anterior choroidal artery aneurysm in a 68-year-old lady. The patient tolerated the procedure well, was discharged without neurologic deficits, and resumed normal life with no aneurysm remnant. The patient consented to the procedure and video/photography publication. RSD is an optimal technique to enhance efficiency and safety when dissecting around the dome of a complex intradural ICA aneurysm. The use of the SThA avoids the risk of ICA or CCA wall damage due to access, which defeats the protective purpose of RSD itself. Video 1 provides an educational example of the SThA cannulation technique for RSD during dissection and clipping of a complex anterior choroidal artery aneurysm.