Comparative Anatomic Analysis of Neuronavigated Transmastoid-Infralabyrinthine Approaches for Jugular Fossa Pathologies: Short Anterior Rerouting Versus Nonrerouting and Tailored Nonrerouting Techniques.

BACKGROUND AND OBJECTIVES: Access to the jugular fossa pathologies (JFPs) via the transmastoid infralabyrinthine approach (TI-A) using the nonrerouting technique (removing the bone anterior and posterior to the facial nerve while leaving the nerve protected within the fallopian canal) or with the short-rerouting technique (rerouting the mastoid segment of the facial nerve anteriorly) has been described in previous studies. The objective of this study is to compare the access to Fisch class C lesions (JFPs extending or destroying the infralabyrinthine and apical compartment of the temporal bone with or without involving the carotid canal) between the nonrerouting and the short-rerouting techniques. Also, some tailored steps to the nonrerouting technique (NR-T) were outlined to enhance access to the jugular fossa (JF) as an alternative to the short-rerouting technique. METHODS: Neuronavigated TI-A was performed using the nonrerouting, tailored nonrerouting, and short-rerouting techniques on both sides of 10 human head specimens. Exposed area, horizontal distance, surgical freedom, and horizontal angle were calculated using vector coordinates for nonrerouting and short-rerouting techniques. RESULTS: The short-rerouting technique had significantly higher values than the NR-T ( P < .01) for the exposed area (169.1 ± SD 11.5 mm 2 vs 151.0 ± SD 12.4 mm 2 ), horizontal distance (15.9 ± SD 0.6 mm vs 10.6 ± SD 0.5 mm 2 ), surgical freedom (19 650.2 ± SD 722.5 mm 2 vs 17 233.8 ± SD 631.7 mm 2 ), and horizontal angle (75.2 ± SD 5.1° vs 61.7 ± SD 4.6°). However, adding some tailored steps to the NR-T permitted comparable access to the JF. CONCLUSION: Neuronavigated TI-A with the short-rerouting technique permits wider access to the JF compared with the NR-T. However, the tailored NR-T provides comparable access to the JF and may be a better option for class C1 and selected class C2 and C3 JFPs.

A new classification of parasagittal bridging veins based on their configurations and drainage routes pertinent to interhemispheric approaches: a surgical anatomical study.

OBJECTIVE: Opening the roof of the interhemispheric microsurgical corridor to access various neurooncological or neurovascular lesions can be demanding because of the multiple bridging veins that drain into the sinus with their highly variable, location-specific anatomy. The objective of this study was to propose a new classification system for these parasagittal bridging veins, which are herein described as being arranged in 3 configurations with 4 drainage routes. METHODS: Twenty adult cadaveric heads (40 hemispheres) were examined. From this examination, the authors describe 3 types of configurations of the parasagittal bridging veins relative to specific anatomical landmarks (coronal suture, postcentral sulcus) and their drainage routes into the superior sagittal sinus, convexity dura, lacunae, and falx. They also quantify the relative incidence and extension of these anatomical variations and provide several preoperative, postoperative, and microneurosurgical clinical case study examples. RESULTS: The authors describe 3 anatomical configurations for venous drainage, which improves on the 2 types that have been previously described. In type 1, a single vein joins; in type 2, 2 or more contiguous veins join; and in type 3, a venous complex joins at the same point. Anterior to the coronal suture, the most common configuration was type 1 dural drainage, occurring in 57% of hemispheres. Between the coronal suture and the postcentral sulcus, most veins (including 73% of superior anastomotic veins of Trolard) drain first into a venous lacuna, which are larger and more numerous in this region. Posterior to the postcentral sulcus, the most common drainage route was through the falx. CONCLUSIONS: The authors propose a systematic classification for the parasagittal venous network. Using anatomical landmarks, they define 3 venous configurations and 4 drainage routes. Analysis of these configurations with respect to surgical routes indicates 2 highly risky interhemispheric surgical fissure routes. The risks are attributable to the presence of large lacunae that receive multiple veins (type 2) or venous complex (type 3) configurations that negatively impact a surgeon's working space and degree of movement and thus are predisposed to inadvertent avulsions, bleeding, and venous thrombosis.

Management of a challenging dura-embedded anterior inferior cerebellar artery loop during a retrosigmoid hearing-preserving vestibular schwannoma resection: microsurgical technique and operative video. Illustrative case.

BACKGROUND: Anatomical variants of the anterior inferior cerebellar artery (AICA), such as an anomalous "AICA loop" embedded in the dura and bone of the subarcuate fossa, increase the complexity and risk of vestibular schwannoma resections. Classically, osseous penetrating AICA loops are the most challenging to mobilize, as the dura must be dissected and the surrounding petrous bone must be drilled to mobilize the AICA away from the surgical corridor and out of harm. OBSERVATIONS: The authors present a rare case of a dura-embedded, osseous-penetrating AICA loop encountered during a hearing-preserving retrosigmoid approach in which they demonstrate safe and efficient microdissection and mobilization of the AICA loop without having to drill the surrounding bone. LESSONS: Although preoperative recognition of potentially dangerous AICA loops has been challenging, thin-sliced petrous bone computed tomography scanning and high-quality magnetic resonance imaging can be useful in preoperative diagnosis. Furthermore, this report suggests that a retrosigmoid approach is superior, as it allows early intradural recognition and proximal vascular control and facilitates more versatile mobilization of AICA loops.

Microneurosurgical treatment of a small perimesencephalic pure pial arterial malformation: an under-recognized etiology of angiographically occult subarachnoid hemorrhage. Illustrative case.

BACKGROUND: Pial arterial malformations (PAMs) are rare vascular lesions consisting of dilated tortuous arteries without venous drainage. Current PAM understanding is limited by the lesion's rarity, limited anatomopathological studies, and frequent misclassifications. OBSERVATIONS: A 23-year-old male experienced two spontaneous subarachnoid hemorrhages (SAHs) over 6 months with initially unremarkable diagnostic cerebral angiograms. Magnetic resonance imaging (MRI) and angiography after the second SAH revealed a small perimesencephalic ovoid lesion within the left crural cistern, between the left superior and posterior cerebral arteries, appearing to be an exophytic cavernoma, a thrombosed aneurysm, or a hemorrhagic tumor. Microsurgical resection was achieved with a pterional craniotomy and anterior clinoidectomy. The resected lesion was characteristic of a pure PAM arising from superior cerebellar arterial branches. LESSONS: Small pure PAMs can be deceitfully dynamic lesions causing episodes of hemorrhage, complete thrombosis (angiographically occult), recanalization, and rehemorrhage. Small thrombosed vascular malformations or aneurysms should be included in differential diagnoses of angiographically occult SAH. MRI can be diagnostic, but the true angioarchitecture can only be elucidated with microneurosurgery. The only definitive cure is removal. The microneurosurgical strategy should account for worst-case scenarios, provide adequate skull base exposures, and include bypass revascularization options when thrombosed aneurysms are encountered.

Intracranial Aneurysms in Loeys-Dietz Syndrome: A Multicenter Propensity-Matched Analysis.

BACKGROUND: Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder characterized by a classic triad of hypertelorism, bifid uvula and/or cleft palate, and generalized arterial tortuosity. There are limited data on the prevalence and rupture risk of intracranial aneurysms (IAs) in the setting of LDS, with no established guidelines. OBJECTIVE: To analyze the prevalence and rupture risk of IA in LDS. METHODS: Electronic medical records of patients with a confirmed diagnosis of LDS and available cerebrovascular imaging were reviewed. Patients were divided into 2 groups based on the presence of IA. Unmatched and propensity-matched analyses were used to identify potential risk factors for aneurysm formation. RESULTS: Records of 1111 patients were screened yielding a total of 60 patients with a diagnosis of LDS. Eighteen (30%) patients had IA, 4 (22.2%) of whom had multiple aneurysms for a total of 24 IAs. Twenty-three (95.8%) aneurysms were located in the anterior circulation; none of them were ruptured. On unmatched analysis, age ( P = .015), smoking history ( P = .034), hypertension ( P = .035), and number of extracranial aneurysms ( P < .001) were significantly higher in patients with IA. After matching for age, sex, race, stroke history, family history, and extracranial aneurysms, smoking history ( P = .009) remained significant. CONCLUSION: Patients with LDS have an increased risk of IAs, especially with a history of smoking. The prevalence rate of IAs in our series was 30%. Screening imaging should be considered at diagnosis, and patients should be encouraged to abstain from smoking. Further studies are needed to elucidate the risk of IA rupture and treatment considerations in this unique population.

Anatomical Engineering and 3D Printing for Surgery and Medical Devices: International Review and Future Exponential Innovations.

Three-dimensional printing (3DP) has recently gained importance in the medical industry, especially in surgical specialties. It uses different techniques and materials based on patients' needs, which allows bioprofessionals to design and develop unique pieces using medical imaging provided by computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, the Department of Biology and Medicine and the Department of Physics and Engineering, at the Bioastronautics and Space Mechatronics Research Group, have managed and supervised an international cooperation study, in order to present a general review of the innovative surgical applications, focused on anatomical systems, such as the nervous and craniofacial system, cardiovascular system, digestive system, genitourinary system, and musculoskeletal system. Finally, the integration with augmented, mixed, virtual reality is analyzed to show the advantages of personalized treatments, taking into account the improvements for preoperative, intraoperative planning, and medical training. Also, this article explores the creation of devices and tools for space surgery to get better outcomes under changing gravity conditions.

Management of Thromboembolic Complications During Aneurysm Coiling: 2-Dimensional Operative Video.

Thromboembolic complications during aneurysm coiling are rare, with higher rates noted in ruptured aneurysms as patients are not usually premedicated with dual antiplatelet therapy.1,2 Management includes a series of escalating strategies, including medical therapy and intra-arterial thrombolysis.3-6 Additional strategies include mechanical thrombectomy with suction aspiration and stent retrievers.3 Intracranial stenting can be used as a last resource, especially in ruptured cases given the need for dual antiplatelets to prevent stent thrombosis.2 We present the case of a 42-yr-old man with a ruptured left internal carotid artery aneurysm with associated intracranial and intraventricular hemorrhage. The patient was initially presented to an outside facility after he was found in bed unable to speak and with right hemiparesis. The patient consented for surgery and underwent external ventricular drain (EVD) placement for the treatment of obstructive hydrocephalus, followed by diagnostic cerebral angiogram and aneurysm coiling. After the deployment of the last coil, control angiogram showed a small filling defect at the interface between the aneurysm neck and the distal vessel. The patient received intravenous heparin for therapeutic ACT and aspirin load. After progressive enlargement of the thrombus, the patient received intra-arterial glycoprotein (GP) IIB/IIIA inhibitors with a microcatheter positioned proximal to the thrombus. As the thrombus mass continued to enlarge, mechanical thrombectomy with an aspiration catheter was performed twice. Follow-up angiogram 20 min after the second aspiration demonstrated near-complete resolution of the thrombus. The patient recovered from his right hemiparesis, and he was discharged to rehabilitation on POD #21.

Multilevel Hemilaminotomy Windows for the Surgical Management of Spinal Epidural Lipomatosis Causing Syringomyelia: Technical Note and Literature Review.

BACKGROUND: Spinal epidural lipomatosis (SEL) is the excessive accumulation of extradural adipose tissue. Severe cases could result in myelopathy, and very rarely, in syringomyelia formation. Surgery has been associated with high morbidity and mortality, and no proven long-term benefits. The objective was to provide a technical description of an efficient and cost-effective procedure for multilevel thoracic decompression without requiring spinal instrumentation. METHODS: A technique of multilevel hemilaminotomy windows is described in a patient with severe thoracic SEL causing syringomyelia. A 3-dimensional spine model was created to illustrate the technique and working angles. We performed a literature review by searching PubMed, Ovid Embase, and Scopus electronic databases with the predetermined inclusion criteria of cases with spinal lipomatosis and a fluid cavity within the spinal cord. RESULTS: The patient's deficit and syringomyelia resolved postoperatively. A review of the literature revealed only 3 cases of syringomyelia secondary to SEL. Syringomyelia expansion occurred in all cases leading to progressive neurologic decline, and surgery with removal of the excessive adipose tissue resolved the syringomyelia and improved the neurologic functioning in all cases. CONCLUSIONS: This technique of multilevel alternating hemilaminotomy "windows" allows for safe and effective decompression and resection of the excessive adipose tissue with reduced operative time and without requiring spine instrumentation. The technique maintains the integrity of the posterior column, thus reducing the risk of postdecompression deformity. Careful bipolar electrocoagulation of internal vertebral veins and meticulous hemostasis is key for minimizing the intraoperative blood loss and avoiding postoperative hematoma formation.

Microsurgical Management of a Primary Neuroendocrine Tumor of the Filum Terminale: A Surgical Technique.

Neuroendocrine tumors (NETs) are benign tumors of the autonomic nervous system that rarely occur in the spinal canal. The gold standard treatment is gross total resection while preserving the patient's neurologic functioning as complete surgical resection is curative. The surgical management of NETs could pose a challenge given their friable consistency, hypervascular nature, and proclivity to adhere to the cauda equina nerve roots. We present a case of a 62-year-old female with an incidental primary NET arising from the filum terminale internum, review the literature, and describe the surgical technique including the benefits of using an intraoperative ultrasound and some of the pitfalls of relying "blindly" on neuromonitoring. Early identification and disconnection of the tumor's vascular pedicle, which usually runs through the cranial filum, devascularizes the tumor, prevents systemic complications from catecholamine release, and facilitates circumferential dissection off the en passage cauda equina nerve roots. Our patient remains neurologically intact and asymptomatic two years postoperatively and neuroimaging confirmed complete resection.

In Vitro Effect of Dovitinib (TKI258), a Multi-Target Angiokinase Inhibitor on Aggressive Meningioma Cells.

Background: Meningiomas represent ∼30% of primary central nervous system (CNS) tumors. Although advances in surgery and radiotherapy have significantly improved survival, there remains an important subset of patients whose tumors have more aggressive behavior and are refractory to conventional therapy. Recent advances in molecular genetics and epigenetics suggest that this aggressive behavior may be due to the deletion of the DNA repair and tumor suppressor gene, CHEK2, neurofibromatosis Type 2 (NF2) mutation on chromosome 22q12, and genetic abnormalities in multiple RTKs including FGFRs. Management of higher-grade meningiomas, such as anaplastic meningiomas (AM: WHO grade III), is truly challenging and there isn't an established chemotherapy option. We investigate the effect of active multi tyrosine receptor kinase inhibitor Dovitinib at stopping AM cell growth in in vitro with either frequent codeletion or mutated CHEK2 and NF2 gene.Methods: Treatment effects were assessed using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, western blot analysis, caspases assay, and DNA fragmentation assay.Results: Treatment of CH157MN and IOMM-Lee cells with Dovitinib suppressed multiple angiokinases-mainly FGFRs, leading to suppression of downstream signaling by RAS-RAF-MAPK molecules and PI3K-AKT molecules which are involved in cell proliferation, cell survival, and tumor invasion. Furthermore, Dovitinib induced apoptosis via downregulation of survival proteins (Bcl-XL), and over-expression of apoptotic factors (Bax and caspase-3) regardless of CHEK2 and NF2 mutation status.Conclusions: This study establishes the groundwork for the development of Dovitinib as a therapeutic agent for high-grade AM with either frequent codeletion or mutated CHEK2 and NF2, an avenue with high translational potential.

Rathke's Cleft Cyst Apoplexy in Two Teenage Sisters.

Rathke's cleft cysts (RCC) are sellar-suprasellar cysts that are usually discovered incidentally given their indolent clinical course. When symptoms do arise, the most common clinical presentation is headache, visual field deficits due to visual pathway compression, diplopia due to cavernous sinus compression, chemical meningitis due to spillage of the cyst contents, endocrine dysfunction, and very rarely apoplexy. We present 2 cases of RCC in sisters who developed a sudden onset of symptoms in a manner similar to pituitary apoplexy. Interestingly, one of them had a very unusual presentation with seizure. We hypothesize that acute symptoms occur due to aggressive intracystic overproduction of mucopolysaccharides (with or without hemorrhage) and a resulting compressive syndrome or local irritation of surrounding structures by spillage of the cyst contents. RCC can be encountered incidentally in family members or may have a familiar predisposition. Since both sisters presented here developed apoplexy symptoms, we propose a more frequent follow-up with sequential imaging in patients with a family history of RCC. Transsphenoidal surgery with evacuation of the cyst contents is the treatment modality of choice, with excellent outcomes.

Flow diversion in vasculitic intracranial aneurysms? Repair of giant complex cavernous carotid aneurysm in polyarteritis nodosa using Pipeline embolization devices: first reported case.

Intracranial aneurysms in polyarteritis nodosa (PAN) are exceedingly rare lesions with unpredictable behavior that pose real challenges to microsurgical and endovascular interventions owing to their inflammatory nature. We introduce a safe and effective alternative for treating these aneurysms using Pipeline embolization devices (PEDs). A 20-year-old man presented with diplopia, headaches, chronic abdominal pain, and weight loss. Diagnostic evaluations confirmed PAN, including bilateral giant cavernous carotid aneurysms. Cyclophosphamide and steroids achieved significant and sustained clinical improvement, with a decision to follow the aneurysms serially. Seven years later the left unruptured aneurysm enlarged, causing a sudden severe headache and a cavernous sinus syndrome. Treatment of the symptomatic aneurysm was pursued using flow diversion (PED) and the internal carotid artery was successfully reconstructed with a total of four overlapping PEDs. At 6 months follow-up, complete exclusion of the aneurysm was demonstrated, with symptomatic recovery. This is the first description of using a flow-diverting technique in an inflammatory vasculitis. In this case, PEDs not only attained a definitive closure of the aneurysm but also reconstructed the damaged and fragile arterial segment affected with vasculitis.