"Curtain-fall" technique for cerebrospinal fluid leak prevention after removal of intradural drainage. Technical note: application in chronic subdural hematoma surgery.

OBJECTIVE: Chronic subdural hematoma (CSDH) is frequently met in neurosurgical practice and often need urgent surgical treatment in case of neurological deterioration. Different surgical approaches to evacuate CSDH are described in the literature. In our experience, an external drainage system is crucial in order to avoid recurrences. We recently encountered a case of subcutaneous CSF collection after drainage removal. Thus, we developed a simple surgical technique to prevent postoperative CSF leak after subdural drainage system removal. METHOD: We have developed a technique in which the periosteum is harvested during the surgery prior to the evacuation of the hemorrhage and fixed with sutures on the uncut dura mater opposite and laterally to the exit of the catheter exiting the dural hole caused by the passage of the Jackson-Pratt subdural drainage system. When the drainage catheter is removed, the flap, partially held by the sutures, falls over the hole avoiding CSF leakage. By using this technique, the small dural hole will be covered with the periosteum allowing for natural closure and wound healing hence preventing CSF leakage. RESULTS: This technique was successfully employed in 21 patients who didn't develop postoperative CSF leakage following CSDH evacuation and removal of subdural drainage system. CONCLUSION: In this technical note, we describe a safe dura closure technique that we developed to help reduce the risk of postoperative CSF leakage following subdural drainage removal, which can, however, also be applied in all surgeries in which a catheter is placed in the subdural space.

Retrosigmoid Intradural Suprameatal Approach: 2-Dimensional Operative Video.

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: The retrosigmoid intradural suprameatal approach is mostly indicated for tumors in the cerebellopontine angle extending toward the Meckel cave and supratentorial regions, most frequently meningiomas and schwannomas. This approach was first established by the senior author in 1982. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Nervous structures: cranial nerves III to XII, cerebellum, and brainstem. Vascular structures: anterior inferior cerebellar artery, posterior inferior cerebellar artery, superior cerebellar artery, basilar artery, vertebral artery, transverse, sigmoid, and petrous sinus, petrosal vein/veins, basilar plexus, and the mastoid emissary vein. Bony structures: petrous bone with internal auditory canal, jugular foramen and suprameatal tubercle, petrous apex, dorsum sellae, and posterior clinoid process. Structures within the petrous bone: vestibule, semicircular canals, and jugular bulb. ESSENTIALS STEPS OF THE PROCEDURE: After a suboccipital retrosigmoid craniectomy in the semisitting position and debulking of the tumor mass in the cerebellopontine angle, extension is achieved by drilling suprameatal tubercle above cranial nerve VII and VIII toward the petrous apex. The extent of bone drilling is tailored for each patient. PITFALLS/AVOIDANCE OF COMPLICATIONS: Avoid damage to cranial nerves, arteries, and veins during drilling, dissection, and tumor removal or by retraction. VARIANTS AND INDICATIONS FOR THEIR USE: In case of extreme supratentorial extensions laterally and dorsally, the opening of the tentorium may be helpful. For inferior extensions toward the upper spinal canal, opening of the foramen magnum and hemilaminectomy of C1 may be necessary.The patient consented to the procedure and to the publication of his/her image. Institutional logo in title slide, © 2023, INI Hannover. Used with permission.

Differences in the MRI Signature and ADC Values of Diffuse Midline Gliomas with H3 K27M Mutation Compared to Midline Glioblastomas.

We conducted a two-center retrospective survey on standard MRI features including apparent diffusion coefficient mapping (ADC) of diffuse midline gliomas H3 K27M-mutant (DMG) compared to midline glioblastomas H3 K27M-wildtype (midGBM-H3wt). We identified 39 intracranial DMG and 18 midGBM-H3wt tumors. Samples were microscopically re-evaluated for microvascular proliferations and necrosis. Image analysis focused on location, peritumoral edema, degree of contrast enhancement and DWI features. Within DMG, MRI features between tumors with or without histomorphological GBM features were compared. DMG occurred in 15/39 samples from the thalamus (38%), in 23/39 samples from the brainstem (59%) and in 1/39 tumors involving primarily the cerebellum (2%). Edema was present in 3/39 DMG cases (8%) versus 78% in the control (midGBM-H3wt) group (p < 0.001). Contrast enhancement at the tumor rim was detected in 17/39 DMG (44%) versus 67% in control (p = 0.155), and necrosis in 24/39 (62%) versus 89% in control (p = 0.060). Strong contrast enhancement was observed in 15/39 DMG (38%) versus 56% in control (p = 0.262). Apparent diffusion coefficient (ADC) histogram analysis showed significantly higher skewness and kurtosis values in the DMG group compared to the controls (p = 0.0016/p = 0.002). Minimum relative ADC (rADC) values, as well as the 10th and 25th rADC-percentiles, were lower in DMGs with GBM features within the DMG group (p < 0.001/p = 0.012/p = 0.027). In conclusion, DMG cases exhibited markedly less edema than midGBM-H3wt, even if histomorphological malignancy was present. Histologically malignant DMGs and midGBM-H3wt more often displayed strong enhancement, as well as rim enhancement, than DMGs without histomorphological malignancy. DMGs showed higher skewness and kurtosis values on ADC-histogram analysis compared to midGBM-H3wt. Lower minimum rADC values in DMGs indicated malignant histomorphological features, likely representing a more complex tissue microstructure.

Analysis of risk factors for venous air embolism in the semisitting position and its impact on outcome in a consecutive series of 740 patients.

OBJECTIVE: Routine use of the semisitting position, which offers several advantages, remains a matter of debate. Venous air embolism (VAE) is a potentially serious complication associated with the semisitting position. In this study, the authors aimed to investigate the safety of the semisitting position by analyzing data over a 20-year period. METHODS: The incidence of VAE and its perioperative management were analyzed retrospectively in a consecutive series of 740 patients who underwent surgery between 1996 and 2016. The occurrence of VAE was defined by detection of bubbles on transthoracic Doppler echocardiography (TTDE) or transesophageal echocardiography (TEE) studies, a decrease of end-tidal CO2 (ETCO2) by 4 mm Hg or more, and/or an unexplained drop in systolic arterial blood pressure (≥ 10 mm Hg). From 1996 until 2013 TTDE was used, and from 2013 on TEE was used. The possible risk factors for VAE and its impact on surgical performance were analyzed. RESULTS: There were 404 women and 336 men with a mean age at surgery of 49 years (range 1-87 years). Surgery was performed for infratentorial lesions in 709 patients (95.8%), supratentorial lesions in 17 (2.3%), and cervical lesions in 14 (1.9%). The most frequent pathology was vestibular schwannoma. TEE had a higher sensitivity than TTDE. While TEE detected VAE in 40.5% of patients, TTDE had a detection rate of 11.8%. Overall, VAE was detected in 119 patients (16.1%) intraoperatively. In all of these patients, VAE was apparent on TTDE or TEE. Of those, 23 patients also had a decrease of ETCO2, 18 had a drop in blood pressure, and 23 had combined decreases in ETCO2 and blood pressure. VAE was detected in 24% of patients during craniotomy before opening the dura mater, in 67% during tumor resection, and in 9% during wound closure. No risk factors were identified for the occurrence of VAE. Two patients had serious complications due to VAE. Surgical performance in vestibular schwannoma surgery was not affected by the presence of VAE. CONCLUSIONS: This study shows that the semisitting position is overall safe and that VAE can be managed effectively. Persistent morbidity is very rare. The authors suggest that the semisitting position should continue to have a place in the standard armamentarium of neurological surgery.

Training model for the intraluminal continuous suturing technique for microvascular anastomosis.

Microvascular anastomosis is a critical procedure in cerebral bypass surgeries. In some rare cases, the extraluminal interrupted technique is not optimal because the vessels are immobile and cannot be rotated, and anastomosis can be performed effectively through the intraluminal continuous suturing technique. The authors reported the application of the intraluminal continuous suturing technique in microanastomosis training with silicone tube, rat's common iliac arteries and abdominal aorta. A silicone tube with a diameter of 1.5 mm was used to practice microanastomosis in intraluminal continuous suturing technique. Then the technique was applied in side-to-side, end-to-side anastomoses of common iliac arteries and the end-to-end abdominal aorta anastomoses of rat. The suturing time and patency rates were compared with an alternative intraluminal continuous suturing technique and one-way-up interrupted suturing technique in silicone tube and rat vessel anastomoses. The intraluminal continuous suturing technique could be gained through practicing with silicone tube, and the technique has also been demonstrated effective in side-to-side, end-to-side anastomoses of common iliac arteries of rat and the abdominal aorta end-to-end anastomoses. In all the animal experimental groups with different suturing techniques, there was no difference between the patency rates, all the immediate patency rate was 100%. There was no significant suturing time difference between the two intraluminal continuous suturing techniques, but the two intraluminal continuous suturing techniques were faster than the interrupted technique. The intraluminal continuous suturing technique described in the study could be used as an efficient method for side-to-side, end-to-side and end-to-end anastomosis, especially under the situation the posterior wall of the anastomosis could not be rotated. Proficiency of the technique could be achieved through practicing in laboratory with silicone tube and live animals.

Elderly Patients with Frontobasal and Suprasellar Meningiomas: Safety and Efficacy of Tumor Removal via Frontolateral Approach.

OBJECTIVE: Many neurosurgeons prefer conservative treatments in the elderly because of higher rates of mortality and morbidity after surgery. We aim to evaluate safety and efficacy of surgery in elderly patients with frontobasal and suprasellar meningiomas with a simple operative procedure, the frontolateral approach. METHODS: Retrospective analysis was made in consecutive patients with meningiomas operated via frontolateral approach. They were divided into 2 groups: elderly group (age ≥ 65 years) and young group (age < 65 years). Multivariate logistic regression analysis was performed for postoperative complications and Karnofsky Performance Scale score (KPS). RESULTS: The study comprises 128 patients operated over a 19-year period, of which 35 patients were in the elderly group and 93 patients were in the young group. More elderly patients presented with American Society of Anesthesiology (ASA) class II and III (57.1% vs. 43%). Gross resection was achieved in 31 cases in the elderly and 85 cases in young group (88.6% vs. 90.3%, P = 0.17). Postoperative KPS in both groups was improved (85.7% vs. 91.4%, P = 0.18). One death occurred in elderly group (2.9%, P = 0.27). Approach-related and medical morbidity in the elderly group was slightly higher than in the young group without significant difference (respectively, 11.4% and 14.3% vs. 9.7% and 8.6%, P = 0.18). Multivariate logistic regression showed increasing age was not associated with approach-related morbidity (odds ratio [OR]: 1.39, P = 0.53), medical morbidity (OR: 1.94, P = 0.88), and improvement of KPS (OR: 0.32, P = 0.25). CONCLUSIONS: Frontobasal and suprasellar meningiomas in elderly patients can be treated surgically with acceptably low morbidity and mortality rates via the frontolateral approach. Preoperative KPS score ≤60 and ASA classification ≥III predict an unfavorable postoperative outcome.

Imaging features and classification of peritumoral edema in vestibular schwannoma.

BACKGROUND: Peritumoral edema (PTE) is rarely present in patients with vestibular schwannomas (VS). We studied the correlation between radiological tumor characteristics and the presence of edema, describe its magnetic resonance imaging features and classify the different edema patterns. METHODS: We analysed 605 consecutive patients treated for VS at our Institute. PTE was found in 30 patients, studied on fluid attenuated inversion recovery sequences and categorised as involving the brachium pontis, cerebellum and/or brainstem. Tumor volume, shape, surface, internal structure and axis of growth were evaluated and compared to a matched series of 30 patients without PTE. RESULTS: In our population of patients, 5% showed PTE. Edema involved the brachium pontis in 22 cases (88%), cerebellum in 15 (60%) and brainstem in 3 (12%). PTE was classified as mild (one region involved), moderate (two regions) and severe (three regions). Edema was present not only perpendicular to the major tumor growth axis but also parallel to it (91%). The difference between the two groups in regards to tumor shape and surface was not significant. We found no correlation between tumor and edema volumes. CONCLUSIONS: VS can cause PTE, but its incidence is less frequent than in skull base meningiomas. PTE involves most frequently the brachium pontis, followed by the cerebellum and brainstem. Its occurrence correlates with tumor size but not with other radiological VS features. PTE is not always located perpendicular to the major axis of tumor growth, which indicated that the compressive theory proposed for meningiomas is not plausible explanation for its manifestation.

Prognostic Significance of Preoperative Geometric Changes in the Internal Acoustic Canal for Hearing Preservation in Vestibular Schwannoma Surgery.

OBJECTIVE: This study focused on the changes in the internal acoustic canal (IAC) caused by vestibular schwannomas (VSs) and their prognostic significance for postoperative hearing outcome. METHODS: A total of 125 consecutive cases of VS were included. We used a neuronavigation software to perform the following measurements on both the tumor side and healthy side: volume of the IAC (VIAC), maximal diameter of the IAC (DIAC), and length of the IAC (LIAC). A statistical analysis was realized using Spearman correlation to test the correlation of the morphometric measure of the IAC and postoperative hearing. Multivariate analysis was performed to test the impact of measurements of the IAC and preoperative hearing on postoperative hearing. RESULTS: The mean VIAC on the tumor side and on the healthy side was 0.271 and 0.169 cm3, respectively. The mean DIAC was 9.438 mm on the tumor side and 7.034 mm contralateral. The correlations tests showed significant correlations of both postoperative hearing deficit and degree of hearing loss with 1) VIAC on the tumor side, 2) difference between VIAC on the tumor side and healthy side, 3) DIAC on the tumor side, and 4) difference between the DIAC on the tumor side and healthy side. The multivariate analysis showed significant impact of the DIAC (P = 0.01) and preoperative hearing status (P = 0.02) on postoperative hearing. CONCLUSIONS: Enlargement of the VIAC and DIAC are negative prognostic factors for hearing preservation. Reasons may be long-standing compression of the auditory nerve and an increased vulnerability of the inner ear structures during the drilling of the IAC.

Can Intraoperative Magnetic Resonance Imaging Be Helpful in the Surgical Resection of Parasellar Meningiomas? A Case Series.

OBJECTIVE: The surgery of parasellar meningiomas is crucial. There are only a few reports of the use of intraoperative magnetic resonance imaging (iMRI) for resection of these lesions. We discuss the safety and usefulness of this technique in achieving the planned surgical goal and analyze patients' outcomes. METHODS: Nineteen cases of parasellar meningioma were treated in our institution using iMRI. We classified the tumors according to their primary location: tuberculum sellae, clinoidal, and cavernous sinus meningiomas. We evaluated the history of previous surgery, outcome, residual (if present) tumor volume, degree of resection, achievement of the surgical goal, and number of iMRI scans. RESULTS: The preoperative surgical goal was achieved in all patients. In 7 of 19 patients, (37%) further tumor resection was performed after the first iMRI scan. Regarding the cavernous sinus group, the surgical resection was continued after the first iMRI in 56% of patients, obtaining substantial additional volume reduction. No complications were found related to the use of iMRI scan. CONCLUSIONS: iMRI has been effective in safely increasing the extent of parasellar meningioma resection mainly for recurrent and invasive tumors. Its usefulness has been seen mostly in cavernous sinus lesions, in which it allowed the further safe resection in 56% of cases. Moreover, this tool was particularly useful in recurrent or residual meningiomas with extension in extracranial compartments.

The Significance of Intraoperative Magnetic Resonance Imaging in Resection of Skull Base Chordomas.

BACKGROUND: Skull base chordoma can be a challenging surgical entity because of its invasive nature. OBJECTIVE: In this study, the role of intraoperative magnetic resonance imaging (iMRI) to optimize the resection of skull base chordomas is evaluated. METHODS: We performed a retrospective analysis of operated patients with skull base chordomas in the setting of iMRI. The clinical records, operative notes, radiologic images, tumor volumetry, location of the residual tumor, and surgical outcome were evaluated. RESULTS: Fifteen patients were operated on for resection of skull base chordomas between 2010 and 2017 in our institution. Gross total resection was planned and achieved in 8 patients and partial resection in 7 patients. In 8 patients (53.3%), the preoperatively planned volume of resection was achieved and confirmed in the first iMRI control. In 7 patients, repeated iMRI controls were required to achieve the surgical target. In 3 patients, the tumor residual requiring further resection was located in the clivus and in 4 patients in the intradural space. The improvement of the preoperative deficits showed a significant statistical association with the resection of the intradural component and decompression of the brainstem. CONCLUSIONS: This study shows that iMRI is a safe method for intraoperative assessment of the degree of resection and the volume and location of residual tumor when resecting skull base chordomas. When gross total resection of the tumor is not feasible, iMRI can be a useful tool for targeted tumor resection.

Magnetic Resonance Imaging-Apparent Diffusion Coefficient Assessment of Vestibular Schwannomas: Systematic Approach, Methodology, and Pitfalls.

OBJECTIVE: To investigate the validity of various approaches to extract quantitative measurements of diffusion imaging (i.e., apparent diffusion coefficient [ADC]) to investigate tumors of the central nervous system. In current studies, the region of interest (ROI) for the quantitative measurements are placed arbitrarily according to morphology. Our aim is to investigate how placement patterns influence the ADC estimation in intracranial tumors. METHODS: Twenty consecutive patients affected by vestibular schwannoma were studied using diffusion imaging. ADC values were obtained using different ROI placement methods: segmentation ADC values of the entire volume (vADC), random ADC values were obtained in 10 different ROI points, and a single ROI in the ADC of the internal auditory canal portion of the tumor. RESULTS: ADC of the internal auditory canal portion of the tumor and vADC differed significantly (P < 0.01). vADC was different between cystic and microcystic schwannomas (P = 0.009) and between cystic and solid schwannomas (P = 0.006). CONCLUSIONS: The positioning of ROI in these measurements is pivotal. Although "whole tumor volume" measurements represent the largest amount of information, multiple seed points can be used as well. However, there must be multiple seeds and their placement must be reported. ADC can be used as a versatile tool for tumor assessment but must be used judiciously and structured to yield comparable results.

Nervus intermedius dysfunctions after vestibular schwannoma surgery: a prospective clinical study.

OBJECTIVE: The purpose of this prospective study was to evaluate the dysfunction of the nervus intermedius (NI) after vestibular schwannoma (VS) surgery. The authors present a clinically feasible method for this purpose. METHODS: In this prospective study, the authors included 30 patients who underwent surgery at the International Neuroscience Institute between May 2014 and February 2017 for resection of VS. The patients' taste sensation was examined using taste strips. Lacrimation was tested using the Schirmer I test. The clinical evaluation was performed before surgery and repeated at 2 weeks and at 6 months after surgery as well as during the follow-up, which extended up to 2 years. The authors tested the correlation between the NI dysfunctions and the House-Brackmann grade of facial nerve palsy. RESULTS: The taste sensation was lost on the side of surgery in 2 patients (6.6%) and decreased in 4 patients (13.3%). The disturbance of taste sensation was not statistically correlated with dysfunctions of the motor portion of the facial nerve. The taste impairment resolved in 4 patients within 6 months, but 2 patients suffered from persistent loss of the taste sensation on the side of surgery during the follow-up. In 23 patients (76.6%), the baseline lacrimation was lower on the side of surgery, and it was significantly correlated with outcome for dysfunctions of the motor portion of the facial nerve. During the follow-up, baseline lacrimation improved in correlation with the improvement in the dysfunctions of the motor portion of the facial nerve. None of the patients reported change in salivation or nasal secretion. CONCLUSIONS: The NI can be affected after VS surgery. The disturbance of baseline lacrimal secretion was correlated with dysfunctions of the motor portion of the facial nerve. However, the disturbance of the taste sensation was not correlated with the grade of facial nerve palsy. Dysfunctions of the NI should be evaluated and separately reported while analyzing facial nerve outcome after VS surgery.

Evaluation of Olfactory Outcome After Frontolateral Approach for Treatment of Suprasellar Tumors.

OBJECTIVE: We present the findings of our prospective study assessing olfactory function outcome in patients undergoing a frontolateral approach for the resection of suprasellar lesions. METHODS: Eighteen consecutive patients (7 females, 11 males) surgically treated at our institute for suprasellar tumors were included in this prospective study. Olfactory function was evaluated at the admission and 14 days after the surgery using the standard 12-item "Sniffin' Sticks" screening (SSS) test. The olfactory outcome was correlated to the following variables: tumor type, size, consistency, and extent of vertical and lateral growth. RESULTS: Preoperative and postoperative SSS test mean values were, respectively, 9.11 and 8.72 (not significant: P = 0.274). In only 1 case (5%), with larger suprasellar extension, the difference between preoperative and postoperative SSS was ≥3 (reduction of 5 points). At the subjective evaluation, no patient stated a deficit in smelling. CONCLUSION: The frontolateral craniotomy is a minimally invasive route to treat suprasellar tumors and has a low approach-related morbidity. It allows tumor resection with low risk for the olfactory function. A risk factor for postoperative olfactory deficit could be significant brain retraction.

Retrosigmoid Intradural Suprameatal-Inframeatal Approach for Complete Surgical Removal of a Giant Recurrent Vestibular Schwannoma with Severe Petrous Bone Involvement: Technical Case Report.

BACKGROUND: Surgical removal of giant vestibular schwannomas with severe petrous bone involvement remains challenging due to the high risk of complications. The retrosigmoid intradural suprameatal-inframeatal approach (RISIA) allows for safe exposure extending from Meckel's cave to the petrous internal carotid artery (ICA). CASE DESCRIPTION: A 27-year-old man presented with recurrence of a giant vestibular schwannoma (4.5 cm) invading Meckel's cave and the left petrous ICA. Symptoms included complete left facial palsy and hearing loss due to tumor invasion and previous operations, as well as left-sided trigeminal hypesthesia, abducens nerve palsy, and lower cranial nerve dysfunction due to tumor compression. The patient also exhibited severe discoordination and ataxia. The tumor was completely resected via the RISIA, which involved drilling of the suprameatal and inframeatal portions of the petrous bone. No approach-related complications were observed. Full recovery of cranial nerve functions (with the exception of those related to the facial and cochlear nerves) and balance were observed postoperatively. CONCLUSIONS: The RISIA allows for safe and effective surgical access during complete tumor resection, even when severe involvement of Meckel's cave and the petrous ICA are observed. The present report is the first to demonstrate the usefulness of this approach in patients with recurrent giant vestibular schwannoma.

Surgical management of cerebellopontine angle arachnoid cysts associated with hearing deficit in pediatric patients.

OBJECTIVE Few cases of cerebellopontine angle (CPA) arachnoid cysts in pediatric patients have been described in the literature, and in only 2 of these cases were the patients described as suffering from hearing deficit. In this article, the authors report on 3 pediatric patients with CPA arachnoid cysts (2 with hearing loss and 1 with recurrent headaches) who underwent neurosurgical treatment at the authors' institution. METHODS Four pediatric patients were diagnosed with CPA arachnoid cysts at the International Neuroscience Institute during the period from October 2004 through August 2012, and 3 of these patients underwent surgical treatment. The authors describe the patients' clinical symptoms, the surgical approach, and the results on long-term follow-up. RESULTS One patient (age 14 years) who presented with headache (without hearing deficit) became asymptomatic after surgical treatment. The other 2 patients who underwent surgical treatment both had hearing loss. One of these children (age 9 years) had recent-onset hypacusia and experienced complete recovery immediately after the surgery. The other (age 6 years) had a longer history (2 years) of progressive hearing loss and showed an interruption of the deficit progression and only mild improvement at the follow-up visit. CONCLUSIONS CPA arachnoid cysts are uncommon in pediatric patients. The indication and timing of the surgical treatment are fundamental, especially when a hearing deficit is present.

Efficiency and Safety of Autologous Fat Grafts in Reconstructing Skull Base Defects After Resection of Skull Base Meningiomas.

BACKGROUND: Reconstruction of the skull base after resection of skull base meningiomas is of paramount importance. Here we describe a safe and effective method of skull base reconstruction using autologous free fat grafts. METHODS: In this retrospective analysis of patients operated for skull base meningioma from 2007 to 2014. We analyzed the surgical technique, efficiency and safety as well as the graft-related complications. RESULTS: Autologous free fat grafts were used in 55 patients, including 39 patients with posterior fossa meningiomas related to the petrous bone and 16 patients with anterior fossa meningiomas related to the paranasal sinuses. Three patients experienced postoperative cerebrospinal fluid (CSF) leak and were managed with temporary continuous lumbar drainage. One patient developed pneumocephalus and required revision. The occurrence of CSF leak was related to aggressive resection with resulting large skull base defects, especially in anterior skull base meningiomas. There were no donor site-related complications. CONCLUSIONS: The use of autologous free fat grafts is an effective and safe technique for reconstructing skull base defects after microsurgical resection of skull base meningiomas.

A technique for sequential, progressive clipping for a giant thrombosed distal anterior cerebral artery aneurysm: Technical note.

BACKGROUND: Giant thrombosed aneurysms often present with thickened walls and a hard thrombus, including in the near-neck aneurysmal sac. These usually make it difficult to achieve complete neck clipping with preservation of local branch patency. Here, we demonstrate a simple but safe and effective technique to overcome these problems in a patient with a 6-cm giant thrombosed distal anterior cerebral artery aneurysm. CASE DESCRIPTION: A 77-year-old-man suffered from loss of volitional activity due to the frontal mass effect. The aneurysm was exposed with unilateral paramedian craniotomy and an interhemispheric approach. The clip was applied to the aneurysmal neck but it slipped onto the parent artery, which caused branch artery occlusion. Intra-aneurysmal thrombectomy was immediately performed near the aneurysmal neck with ultrasonic aspiration. The next clip was added along the aneurysm side of the preceding clip, which was then removed. This procedure was repeated twice so that complete neck clipping was achieved while preserving the branch patency. All the residual thrombus and aneurysmal wall were subsequently removed. Postoperatively, there was no additional neurological deficit. The patient's mental function was significantly improved. CONCLUSIONS: We conclude that the sequential, progressive clipping technique is a robust option for successful neck clipping of giant thrombosed aneurysms.