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Sharad Rajpal, David B. Niemann and Aquilla S. Turk

✓Venous outlet obstruction has recently been reported to be a potentially treatable cause of benign intracranial hypertension (BIH). In the English-language literature only 18 cases, all from the UK and Australia, involving the use of transverse sinus stenosis stent treatment for BIH have been reported; the youngest patient to receive treatment was a 17-year-old girl. The authors report the case of a 15-year-old boy who presented with headache, papilledema, decreased visual acuity, and diploplia who underwent successful unilateral transverse sinus stenosis stenting and experienced complete resolution of symptoms.

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Mustafa K. Başkaya, Azam S. Ahmed, Özkan Ateş and David Niemann

Object

Blood blister–like aneurysms (BBAs) arise from the supraclinoid internal carotid artery (ICA) at non-branching sites. These aneurysms are challenging to treat primarily with either surgical clip placement or endovascular therapy. The authors describe a series of 4 patients who presented with high-grade subarachnoid hemorrhage (SAH) due to a BBA, which was treated with an extracranial–intracranial (EC–IC) bypass followed by trapping of the aneurysm.

Methods

Four patients presented with SAH due to a BBA of the ICA. Three of these patients were treated with an endovascular procedure; following the vasospasm period, definitive treatment with EC–IC bypass followed by trapping of the aneurysmal parent vessel was performed.

Results

Two of the patients who were treated endovascularly suffered rebleeding prior to bypass and trapping. Three of the 4 patients had a good outcome (modified Rankin Scale Score 1 or 2), and 1 patient who suffered 2 episodes of rebleeding died.

Conclusions

Treatment of BBAs of the ICA remains difficult, particularly in the setting of high-grade SAH. Patients with this challenging condition often require multiple procedures and have a high incidence of rebleeding. Definitive treatment of these aneurysms consists of EC–IC bypass and surgical or endovascular trapping.

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Sharad Rajpal, David B. Niemann, Beverly Aagaard-Kienitz and Aquilla S. Turk

✓ A case of cranial-based metastatic non-Hodgkin lymphoma with cerebral vascular compromise is presented. The patient underwent intracranial endovascular stent placement resulting in an improvement in his symptoms. This is the first reported case of endovascular stent placement for an intracranial neoplasm in the literature to date.

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Özkan Ateş, Azam S. Ahmed, David Niemann and Mustafa K. Başkaya

Object

The microsurgical anatomy of the occipital artery (OA) was studied to describe the diameter, length, and course of this vessel as it pertains to revascularization procedures of the posterior cerebral circulation.

Methods

The authors studied 12 OAs in 6 cadaveric heads that had been injected with colored latex. They evaluated the OA's ability to serve as a conduit for extracranial–intracranial (EC–IC) bypass in the posterior circulation. They measured the length of the OA and its diameter at common sites of anastomosis and compared these values with the diameters of the recipient vessels (V3 and V4 segments of the vertebral artery, caudal loop of the posterior inferior cerebellar artery [PICA], and anterior inferior cerebellar artery [AICA]).

Results

The mean thickness of the suboccipital segment of the OA was found to be 1.9 mm. The mean distance of the OA from the external occipital protuberance was found to be 45 mm. The mean length of the suboccipital segment of the OA was 79.3 mm. The mean thickness of the largest trunk of the V3 segment, the V4 segment, the caudal loop of the PICA, and the AICA were 3.3 mm, 3.1 mm, 1.2 mm, and 1 mm, respectively.

Conclusions

The length, diameter, and flow accomodated by the OA make it an ideal choice as a conduit for posterior circulation bypass. The bypass from the OA to the caudal loop of the PICA demonstrates the least difference in vessel diameter, and is therefore best suited for EC–IC bypass procedures in the posterior circulation.

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Hakan Seçkin, Emel Avci, Kutluay Uluç, David Niemann and Mustafa K. Başkaya

Object

The aim of this study was to describe the microsurgical anatomy of the orbitozygomatic craniotomy and its modifications, and detail the stepwise dissection of the temporalis fascia and muscle and explain the craniotomy techniques involved in these approaches.

Methods

Nine cadaveric embalmed heads injected with colored silicone were used to demonstrate a stepwise dissection of the 3 variations of orbitozygomatic craniotomy. The craniotomies and dissections were performed with standard surgical instruments, and the microsurgical anatomy was studied under microscopic magnification and illumination.

Results

The authors performed 2-piece, 1-piece, and supraorbital orbitozygomatic craniotomies in 3 cadaveric heads each. Stepwise dissection of the temporalis fascia and muscle, and osteotomy cuts were shown and the relevant microsurgical anatomy of the anterior and middle fossae was demonstrated in cadaveric heads. Surgical case examples were also presented to demonstrate the application of and indications for the orbitozygomatic approach.

Conclusions

The orbitozygomatic approach provides access to the anterior and middle cranial fossae as well as the deep sellar and basilar apex regions. Increased bone removal from the skull base obviates the need for vigorous brain retraction and offers an improved multiangled trajectory and shallower operative field. Modifications to the orbitozygomatic approach provide alternatives that can be tailored to particular lesions, enabling the surgeon to use the best technique in each individual case rather than a “one size fits all” approach.

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Ulas Cikla, Balkan Sahin, Sahin Hanalioglu, Azam S. Ahmed, David Niemann and Mustafa K. Baskaya

OBJECTIVE

Cerebrovascular bypass surgery is a challenging yet important neurosurgical procedure that is performed to restore circulation in the treatment of carotid occlusive diseases, giant/complex aneurysms, and skull base tumors. It requires advanced microsurgical skills and dedicated training in microsurgical techniques. Most available training tools, however, either lack the realism of the actual bypass surgery (e.g., artificial vessel, chicken wing models) or require special facilities and regulations (e.g., cadaver, live animal, placenta models). The aim of the present study was to design a readily accessible, realistic, easy-to-build, reusable, and high-fidelity simulator to train neurosurgeons or trainees on vascular anastomosis techniques even in the operating room.

METHODS

The authors used an anatomical skull and brain model, artificial vessels, and a water pump to simulate both extracranial and intracranial circulations. They demonstrated the step-by-step preparation of the bypass simulator using readily available and affordable equipment and consumables.

RESULTS

All necessary steps of a superficial temporal artery–middle cerebral artery bypass surgery (from skin opening to skin closure) were performed on the simulator under a surgical microscope. The simulator was used by both experienced neurosurgeons and trainees. Feedback survey results from the participants of the microsurgery course suggested that the model is superior to existing microanastomosis training kits in simulating real surgery conditions (e.g., depth, blood flow, anatomical constraints) and holds promise for widespread use in neurosurgical training.

CONCLUSIONS

With no requirement for specialized laboratory facilities and regulations, this novel, low-cost, reusable, high-fidelity simulator can be readily constructed and used for neurosurgical training with various scenarios and modifications.

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Mustafa K. Başkaya, Mark W. Kiehn, Azam S. Ahmed, Özkan Ateş and David B. Niemann

Object

Arterial bypass is an important method of treating intracranial disease requiring sacrifice of the parent vessel. The conduits for extracranial–intracranial (EC–IC) bypass surgery include the superficial temporal artery, occipital artery, superior thyroid artery, radial artery, and saphenous vein (long or short). In an aging population with an increased prevalence of vascular disease, conduits for EC–IC bypass may be in short supply in some patients. Herein, the authors describe a case in which the descending branch of the lateral circumflex femoral artery (DLCFA) was utilized as a high-flow conduit for an EC–IC bypass.

Methods

This 22-year-old woman presented with irregular menstrual periods, secondary amenorrhea, and hypothyroidism. A giant intrasellar and suprasellar mass was found. Angiography confirmed a 3.5 × 2.1–cm fusiform aneurysm involving the cavernous and supraclinoid segments of the right internal carotid artery. A suitable radial artery conduit was not available. The DLCFA was harvested and anastomosed between the M2 segment of the middle cerebral artery and the external carotid artery.

Results

Durable clinical and angiographic results were apparent at the 2-month follow-up.

Conclusions

The DLCFA's diameter and length were used successfully in a high-flow EC–IC bypass surgery. The DLCFA may be a good alternative to radial artery and saphenous vein grafts for an EC–IC bypass requiring high flow.

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Nathaniel P. Brooks, Aquilla S. Turk, David B. Niemann, Beverly Aagaard-Kienitz, Kari Pulfer and Thomas Cook

Object

There is little evidence addressing whether procedures requiring adjunctive devices lead to an increased frequency of thromboembolic complications. The authors report their experience with 155 aneurysms treated with and without adjunctive devices.

Methods

The authors retrospectively reviewed their last 155 aneurysm coil placement procedures. The patients' records were reviewed for the following phenomena: 1) evidence of procedure-related thrombus formation; 2) clinical evidence of stroke; and 3) the presence of acute ischemia in the treated vascular territory on diffusion-weighted (DW) imaging.

Results

Of the 155 aneurysms treated in 132 patients, 66 were treated with coils only, 45 had stent-assisted coil placement, 33 underwent balloon remodeling, and in 11 stents were placed after balloon remodeling. Small DW imaging abnormalities were present in the treated vascular territory in 24% of cases (37 lesions). Specifically, 21 (32%) of 66 lesions in the coil-treated group, 6 (13%) of 45 in the stent-assisted coil treatment group, 8 (24%) of 33 in the balloon remodeling group, and 2 (18%) of 11 in the balloon and stent group showed DW imaging positivity. Furthermore, 25 (68%) of the 37 cases that were positive on DW imaging occurred in patients presenting with subarachnoid hemorrhage (SAH). Clinically evident stroke or transient ischemic attack was present in 10 (27%) of 37 cases, with 70% occurring in patients presenting with SAH.

Conclusions

Use of adjunctive devices in treating aneurysms does not appear to increase the frequency of embolic or ischemic events. The presence of DW imaging abnormalities and clinically evident stroke was actually less frequent when adjunctive devices were used and in electively treated cases. This was probably related to perioperative antiplatelet medical management.

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Yiping Li, Jason Kim, Dustin Simpson, Beverly Aagaard-Kienitz, David Niemann, Ignatius N. Esene and Azam Ahmed

OBJECTIVE

The literature suggests that blood-brain barrier disruption (BBBD) plays a significant role in the development of neurological events in patients with diffusion-weighted imaging (DWI) that is negative for lesions. In this prospective, single-center cohort study, the authors compared the imaging characteristics of patients suffering transient neurological events (TNEs) with those in patients suffering permanent neurological events (PNEs) after having undergone elective embolization of unruptured intracranial aneurysms.

METHODS

This prospective cohort study was conducted between July 2016 and June 2019. Inclusion criteria were adults undergoing elective neuroendovascular procedures and the absence of contraindications to MRI. All subjects underwent brain MRI including postcontrast FLAIR (pcFLAIR) sequences for evaluation of BBBD within 24 hours postprocedure.

RESULTS

In total, 128 patients harboring 133 unruptured aneurysms were enrolled, 109 of whom (85.2%) showed some degree of BBBD on pcFLAIR MRI and 50 of whom (39.1%) suffered an ischemic insult per DWI. In total, 23 patients (18%) suffered neurological complications, 16 of which (12.5%) were TNEs and 7 of which (5.5%) were PNEs. The median extent of BBBD was focal in asymptomatic patients as compared to hemispheric and lobar in the TNE and PNE groups, respectively (p < 0.001). The American Society of Anesthesiologists physical status classification predicted the extent of BBBD (p = 0.046).

Lesions on DWI were noted in 34 asymptomatic patients (32.4%) compared to 9 patients (56.3%) with TNEs and all 7 patients (100%) with PNEs (p < 0.001). The median number of DWI lesions was 0 (range 0–18 lesions) in the asymptomatic group compared to 1.5 (range 0–8 lesions) and 8 (range 1–13 lesions) in the TNE and PNE groups, respectively (p < 0.001). Smoking (p = 0.008), older age (p = 0.002), and longer surgery (p = 0.006) were positively associated with the number of lesions on DWI.

On multivariate analysis, intraarterial verapamil (p = 0.02, OR 8.01, 95% CI 1.35–47.43) and extent of BBBD (p < 0.001, OR 58.58, 95% CI 9.48–361.84) were positively associated with the development of TNEs, while intravenous infusion of midazolam during surgery (p = 0.02, OR 6.03, 95% CI 1.29–28.20) was negatively associated. An increased number of lesions on DWI was the only significant predictor for the development of PNEs (p < 0.001, OR 49.85, 95% CI 5.56–447.10).

CONCLUSIONS

An increasing extent of BBBD was associated with the development of TNEs, whereas an increasing number of lesions on DWI was significantly associated with the development of PNEs. BBBD imaging using pcFLAIR may serve as a valuable biomarker for detecting subtle cerebral ischemia and stratifying the risk for ischemic events.

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Matthew F. Sanford, Aquilla S. Turk, David B. Niemann, Kari A. Pulfer and Beverly A. Aagaard-Kienitz

✓ The authors describe the novel use of cerebral perfusion computerized tomography studies to evaluate the effectiveness of internal carotid artery stent placement in a man with symptomatic transient ischemic attacks caused by tandem stenoses of the internal carotid and middle cerebral arteries.