Posterior Interhemispheric Transtentorial Subsplenial Approach for Posterior Thalamic Tumors: 2-Dimensional Operative Video.

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: The posterior interhemispheric transtentorial subsplenial approach provides a direct corridor to posterior thalamic lesions without a cortical or callosal incision. 1. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: This corridor is through the posterior interhemispheric fissure along the medial surface of the cuneus and allows the subsplenial region to be explored. Evaluating the tumor's size and extension is crucial to determining the suitability of this approach. The deep venous system may be displaced from mass effect, requiring preoperative venous examination. ESSENTIALS STEPS OF THE PROCEDURE: A 34-year-old male patient was admitted elsewhere with blurred vision and imbalance. MRI revealed a right-sided posterior thalamic tumor with heterogeneous contrast enhancement. The patient was followed-up after placement of a ventriculoperitoneal shunt. Seven months later, he was admitted to our clinic because the tumor had grown. The patient underwent surgical intervention. The patient was placed in the prone oblique position. After dural opening, the quadrigeminal cistern was opened to release cerebrospinal fluid, allowing significant gravity relaxation of the ipsilateral hemisphere. The tentorium was cut and retracted to achieve the necessary exposure. PITFALLS/AVOIDANCE OF COMPLICATIONS: The most serious complications of this approach occur from vascular injuries. Gravitational retraction of the occipital lobe protects the optic radiation, and anatomic landmarks help the surgeon maintain anatomic orientation. VARIANTS AND INDICATIONS FOR THEIR USE: The perimedian supracerebellar transtentorial approach is an alternative to the posterior interhemispheric transtentorial subsplenial approach for lesions in this area; however, the indications and limits of these approaches have some differences.The patient consented to the procedure and to the publication of his/her image.Images at 0:29 reused from Serra et al, 1 with permission from Elsevier.

Back to basal: contemporary cerebrovascular cohort study of the supratentorial-infraoccipital approach.

OBJECTIVE: The objective of this paper was to assess applications of the supratentorial-infraoccipital (STIO) approach for cerebrovascular neurosurgery. METHODS: The authors conducted a cohort study of all consecutive cases in which the STIO approach was used during the study period, December 1995 to January 2021, as well as a systematic review of the literature. RESULTS: Twenty-five cerebrovascular cases were identified in which the STIO approach was used. Diagnoses included arteriovenous malformation (n = 15), cerebral cavernous malformation (n = 5), arteriovenous fistula (n = 4), and aneurysm (n = 1). The arteriovenous malformations consisted of Spetzler-Martin grade II (n = 3), grade III (n = 8), and grade IV (n = 4) lesions. Lesion locations included the occipital lobe (n = 15), followed by the tentorial dural (n = 4), temporal-occipital (n = 3), temporal (n = 1), thalamic (n = 1), and quadrigeminal cistern (n = 1) regions. Many patients (75%) experienced transient visual deficits attributable to retraction of the occipital lobe, all of which resolved. As of last follow-up (n = 12), modified Rankin Scale scores had improved for 6 patients and were unchanged for 6 patients compared with the preoperative baseline. CONCLUSIONS: The STIO approach is a safe and effective skull base approach that provides a specialized access corridor for appropriately selected cerebrovascular lesions.

Occipital Interhemispheric Transtentorial Approach for Microsurgical Resection of a Ruptured Vermian Arteriovenous Malformation: Three-Dimensional Operative Video.

Cerebellar arteriovenous malformations (AVMs) are associated with higher risk of rupture compared with cerebral AVMs.1 Microsurgical resection of a ruptured AVM, measuring 3 cm in its largest dimension, within the cerebellar vermis and right parasagittal cerebellar lobe is demonstrated in Video 1. Cerebral angiography showed major supply from both superior cerebellar arteries and minor supply from a right anterior inferior cerebellar artery-posterior inferior cerebellar artery variant. Venous drainage was through a single ectatic vermian vein draining toward the torcula. Intraoperatively, a second, thrombosed, draining vein connected to the vein of Galen was identified. A right interhemispheric occipital transtentorial approach was elected over the supracerebellar infratentorial approach for early access to the superior cerebellar artery feeding arteries and for an orthogonal rather than a tangential view. The patient was positioned in an ipsilateral lateral position with the head turned 45° toward the floor allowing for gravity retraction of the ipsilateral occipital lobe. An external ventricular drain was also inserted to allow for further relaxation of the occipital lobe. Under neuronavigation guidance, the tentorium was opened allowing immediate visualization of the AVM with early control of the superior cerebellar artery arterial feeders. The AVM was removed using standard microsurgical technique, and hematoma was evacuated. Postoperative cerebral angiography demonstrated no AVM residual. The patient was discharged to a rehabilitation institute with minor residual cerebellar deficits. The patient provided written informed consent for the procedure, video recording, and publication.

A cerebral arteriovenous malformation mistakenly diagnosed as dry eye and glaucoma: a case report.

BACKGROUND: To report the first case of a cerebral arteriovenous malformation (AVM) with ocular symptoms and review the characteristics of this case and the main point of confusion for the diagnosis of such a case. CASE PRESENTATION: A 58-year-old woman presented to the ophthalmology clinic with 1 and a half years of right eye redness, ocular hypertension and recurrent headache. One and a half years ago she was diagnosed with right eye dry eye and glaucoma and had received treatment according to this diagnosis. However, none of the treatments led to any improvement in redness and headache. Physical examination revealed dry eye and severe corkscrew hyperaemia with dilated vessels in the right eye. The results of fundoscopic examination of both eyes were normal. After we considered that the symptoms may be related to abnormal intracranial vessels, computed tomography angiography and venography (CTA + CTV) were performed, and the results showed an arteriovenous malformation in the right parietal-occipital area in the brain. The AVM was definitively located by further examination with digital subtraction angiography (DSA). After AVM endovascular embolism treatment, the conjunctival congestion of the right eye was significantly relieved, and the intraocular pressure decreased to normal. CONCLUSION: In clinical practice, when corkscrew hyperaemia accompanied by neurological symptoms is found, cerebral vascular diseases might be considered. In this case, the ophthalmologist's diagnosis should combine disease history and imaging examination.

Clinical importance of the occipital artery in vascular lesions: A review of the literature.

The occipital artery (OA) is a critical artery in vascular lesions. However, a comprehensive review of the importance of the OA is currently lacking. In this study, we used the PubMed database to perform a review of the literature on the OA to increase our understanding of its role in vascular lesions. We also provided our typical cases to illustrate the importance of the OA. The OA has several variations. For example, it may arise from the internal carotid artery or anastomose with the vertebral artery. Therefore, the OA may provide a crucial collateral vascular supply source and should be preserved in these cases. The OA is a good donor artery. Consequently, it is used in extra- to intracranial bypasses for moyamoya disease (MMD) or aneurysms. The OA can be involved in dural arteriovenous fistula (DAVF) and is a feasible artery for the embolisation of DAVF. True aneurysms and pseudoaneurysms can occur in the OA; surgical resection and embolisation are the effective treatment approaches. Direct high-flow AVF can occur in the OA; embolisation treatment is a good option in such cases. The OA can also be involved in MMD and brain arteriovenous malformation (AVM) by forming transdural collaterals. For a patient in the prone position, if occipital and suboccipital craniotomies are performed, the OA can also be used for intraoperative angiography. In brief, the OA is a very important artery in vascular lesions.

Posterior occipital intramuscular hemangioma mimicking arteriovenous malformation: Case report.

RATIONALE: Intermuscular hemangioma (IH) usually occurs in the muscles of the limbs and trunk, but can rarely occur in the occipital region. IH in the occipital region is easily misdiagnosed as arteriovenous malformation (AVM). PATIENT CONCERNS: A 31-year-old woman had a right occipital mass for 5 months without pulsation. DIAGNOSIS: Head computered tomography angiography (CTA) and digital substraction angiography (DSA) examinations showed that the lesion was mainly vascular, approximately 3 × 5 cm in size, and supplied by occipital arteries and the muscular branches of vertebral arteries. The venous drainage of the lesions communicated with the suboccipital vein plexus and the paravertebral vein in the venous phase, indicating AVM. Postoperative histological investigation showed the lesion was a hemangioma. INTERVENTIONS: It was recommended for surgical removal. The surgery was carried out under general anesthesia. The lesion showed a clear boundary. The occipital artery touched the anterior margin of the lesion, was exposed and ligated, and was removed around the lesion. The lesion consisted of massive blood vessels, and the surrounding muscles were swollen, indicating IH.After the lesion was removed, the normal muscle tissue around the lesion was also removed. OUTCOMES: The patient achieved a good recovery after surgery, and pathology confirmed IH. A postoperative 1-year CTA review was performed and showed partial residual, then the radiotherapy was recommended. She refused further radiotherapy, follow-up 2 years later showed no enlargement of the lesion. LESSONS: Although IH rarely occurs in the occipital region, this can occur. Due to the complexity of the drainage veins in the occipital region, these IH are prone to misdiagnosis as AVM.

Congenital Cirsoid aneurysm communicating with the sagittal sinus and supplied by extra and intracranial arteries.

We describe the unique case of a 6-year old boy who presented with recalcitrant generalized tonic-clonic seizures and clinicoradiological features of congenital Cirsoid aneurysm. The lesion was supplied by occipital arteries and a large right parietal parasagittal intracranial feeding artery in a Yokouchi type C pattern. The venous drainage was communicating with the posterior part of the superior sagittal sinus. Six months after successful ligation of the feeding arteries and complete surgical excision of the lesion, the patient remains seizure free.

Decreased regional cerebral blood flow in patients with diphenylarsinic acid intoxication.

BACKGROUND AND PURPOSE: Diphenylarsinic acid (DPAA) intoxication caused by drinking contaminated well water was found in Kamisu, Japan. The symptoms indicated cerebellar-brainstem and temporo-occipital involvement. However, it remains unclear how it affects the human brain. To elucidate the effect of DPAA on the human brain, we analyzed cerebral blood flow (CBF) data after the drinking of DPAA-contaminated water was stopped and investigated the correlation between DPAA exposure level and CBF by single-photon emission computed tomography (CBF-SPECT). METHODS: The DPAA-exposed inhabitants (n = 78) were divided into 35 symptomatic and 43 asymptomatic subjects and compared with 38 healthy controls. The DPAA concentration in nails or hair and well water was measured using a high-performance liquid chromatography system and coupled plasma mass spectrometry after adequate extraction treatment. CBF-SPECT data, obtained within 1 year after the drinking of contaminated well water was stopped, were analyzed by statistical parametric mapping. We also examined the relationship between variations in CBF-SPECT signals and variations in DPAA concentrations in the hair or nails of the subjects. RESULTS: Compared with control subjects, CBF in symptomatic DPAA-exposed subjects was significantly lower in the occipital lobe, including the cuneus and inferior occipital gyri. The DPAA concentration in the nails or hair of subjects was inversely and significantly related to their CBF. CONCLUSION: These data suggest that CBF-SPECT may be useful as a clinical marker to infer the effect of accumulated DPAA on the brain.

Prevalence of Anomalously Originating Occipital Artery in a Group of Turkish Individuals: A Retrospective Study using Angiography.

AIM: To investigated the prevalence of anomalously originating occipital artery (OA) using angiography in a group of Turkish individuals. MATERIAL AND METHODS: The images recorded in the picture archiving and communication system for a total of 114 patients, in which the whole vertebral artery, as well as the external carotid artery (ECA) and its branches, were visualized, were retrospectively reviewed. Images were obtained using a Toshiba INFNX-i 8000V (Canon Medical Systems, Otawara, Tochigi, Japan) angiography device. RESULTS: We diagnosed 11 cases (12 arteries) with anomalously originating OA, representing a prevalence of 9.64%. In 7 cases, the ascending pharyngeal artery and OA originated with a common root from the ECA (8 arteries); and in 4 patients, OA originated from the distal part of the ECA (C1 vertebral level). CONCLUSION: As for many vascular structures, the prevalence of OA variations may vary according to the population under question and the examination method used. Our study has shown that in a sample from the Turkish population, the prevalence of anomalously originating OA was much higher than that stated in the literature, which used magnetic resonance angiography. To avoid complications, the high prevalence of this anomaly must be taken into account during surgeries that require the use of OA, endarterectomies, and endovascular interventions.

Neurorehabilitation of saccadic ocular movement in a patient with a homonymous hemianopia postgeniculate caused by an arteriovenous malformation: A Case Report.

RATIONALE: Visual therapy, which includes a restorative and compensatory approach, seems to be a viable treatment option for homonymous defects of the visual field in patients with postgeniculate injury of the visual pathway, due to occipital arteriovenous malformation (AVM). Until now, the Mexican population suffering from homonymous hemianopia did not have health services that provided any type of visual therapy for their condition. PATIENT CONCERNS: A 31-year-old patient, who underwent a surgical procedure for resection of the AVM, was referred with posterior low vision on the left side. DIAGNOSES: The patient was diagnosed with left homonymous hemianopia. INTERVENTIONS: Visual neurorehabilitation therapy (NRT), which integrated restorative and compensatory approaches, was administered for 3 hours each week. NRT included fixation, follow-up, search, peripheral vision, and reading. OUTCOMES: The NRT did not change visual field defects and, retinotopocally, the same campimetric defects remained. However, after training the tracking ocular movements improved to standard values on the ENG, further, the visual search became more organized. The reading reached a level without mistakes, with rhythm and goog intonation. The Beck test demostrated an improvement in depression symptoms. Regarding the daily life activities, the patient reported significant improvements. LESSONS: Visual NRT can significantly improve eye movements, as well as the quality of life and independence of the patient. This integral approach could be an effective therapeutic option for homonymous defects of the visual field.

The transperiosteal "inside-out" occipital artery harvesting technique.

OBJECTIVE The occipital artery (OA) is a frequently used donor vessel for posterior circulation bypass procedures due to its proximity to the recipient vessels and its optimal caliber, length, and flow rate. However, its tortuous course through multiple layers of suboccipital muscles necessitates layer-by-layer dissection. The authors of this cadaveric study aimed to describe a landmark-based novel anterograde approach to harvest OA in a proximal-to-distal "inside-out" fashion, which avoids multilayer dissection. METHODS Sixteen cadaveric specimens were prepared for surgical simulation, and the OA was harvested using the classic (n = 2) and novel (n = 14) techniques. The specimens were positioned three-quarters prone, with 45° contralateral head rotation. An inverted hockey-stick incision was made from the spinous process of C-2 to the mastoid tip, and the distal part of the OA was divided to lift up a myocutaneous flap, including the nuchal muscles. The OA was identified using the occipital groove (OG), the digastric muscle (DM) and its groove (DG), and the superior oblique muscle (SOM) as key landmarks. The OA was harvested anterogradely from the OG and within the flap until the skin incision was reached (proximal-to-distal technique). In addition, 35 dry skulls were assessed bilaterally (n = 70) to study additional craniometric landmarks to infer the course of the OA in the OG. RESULTS The OA was consistently found running in the OG, which was found between the posterior belly of the DM and the SOM. The mean total length of the mobilized OA was 12.8 ± 1.2 cm, with a diameter of 1.3 ± 0.1 mm at the suboccipital segment and 1.1 ± 0.1 mm at the skin incision. On dry skulls, the occipitomastoid suture (OMS) was found to be medial to the OG in the majority of the cases (68.6%), making it a useful landmark to locate the OG and thus the proximal OA. CONCLUSIONS The anterograde transperiosteal inside-out approach for harvesting the OA is a fast and easy technique. It requires only superficial dissection because the OA is found directly under the periosteum throughout its course, obviating tedious layer-by-layer muscle dissection. This approach avoids critical neurovascular structures like the vertebral artery. The key landmarks needed to localize the OA using this technique include the OMS, OG, DM and DG, and SOM.

TGFß pathway deregulation and abnormal phospho-SMAD2/3 staining in hereditary cerebral hemorrhage with amyloidosis-Dutch type.

Hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D) is an early onset hereditary form of cerebral amyloid angiopathy (CAA) pathology, caused by the E22Q mutation in the amyloid ß (Aß) peptide. Transforming growth factor ß1 (TGFß1) is a key player in vascular fibrosis and in the formation of angiopathic vessels in transgenic mice. Therefore, we investigated whether the TGFß pathway is involved in HCHWA-D pathogenesis in human postmortem brain tissue from frontal and occipital lobes. Components of the TGFß pathway were analyzed with quantitative RT-PCR. TGFß1 and TGFß Receptor 2 (TGFBR2) gene expression levels were significantly increased in HCHWA-D in comparison to the controls, in both frontal and occipital lobes. TGFß-induced pro-fibrotic target genes were also upregulated. We further assessed pathway activation by detecting phospho-SMAD2/3 (pSMAD2/3), a direct TGFß down-stream signaling mediator, using immunohistochemistry. We found abnormal pSMAD2/3 granular deposits specifically on HCHWA-D angiopathic frontal and occipital vessels. We graded pSMAD2/3 accumulation in angiopathic vessels and found a positive correlation with the CAA load independent of the brain area. We also observed pSMAD2/3 granules in a halo surrounding occipital vessels, which was specific for HCHWA-D. The result of this study indicates an upregulation of TGFß1 in HCHWA-D, as was found previously in AD with CAA pathology. We discuss the possible origins and implications of the TGFß pathway deregulation in the microvasculature in HCHWA-D. These findings identify the TGFß pathway as a potential biomarker of disease progression and a possible target of therapeutic intervention in HCHWA-D.

Variations of Occipital Artery-Posterior Inferior Cerebellar Artery Bypass: Anatomic Consideration.

BACKGROUND: Advances in diagnosis of posterior inferior cerebellar artery (PICA) aneurysms have revealed the high frequency of distal and/or dissecting PICA aneurysms. Surgical treatment of such aneurysms often requires revascularization of the PICA including but not limited to its caudal loop. OBJECTIVE: To examine the microsurgical anatomy involved in occipital artery (OA)-PICA anastomosis at various anatomic segments of the PICA. METHODS: Twenty-eight PICAs in 15 cadaveric heads were examined with the operating microscope to take morphometric measurements and explore the specific anatomy of bypass procedures. RESULTS: OA bypass to the p2, p3, p4, or p5 segment was feasible with a recipient vessel of sufficient diameter. The loop wandering near the jugular foramen in the p2 segment provided sufficient length without requiring cauterization of any perforating arteries to the brainstem. Wide dissection of the cerebellomedullary fissure provided sufficient exposure for the examination of some p3 segments and all p4 segments hidden by the tonsil. OA-p5 bypass was placed at the main trunk before the bifurcation in 5 hemispheres and at the larger hemispheric trunk in others. CONCLUSION: Understanding the possible variations of OA-PICA bypass may enable revascularization of the appropriate portion of the PICA when the parent artery must be occluded. A detailed anatomic understanding of each segment clarifies important technical nuances for the bypass on each segment. Dissection of the cerebellomedullary fissure helps to achieve sufficient exposure for the bypass procedures on most of the segments.

Ultrasonography of occipital arteries to diagnose giant cell arteritis: a case series and literature review.

We describe four cases of giant cell arteritis (GCA) that presented with occipital headache in the last 6 months. Typical ultrasound features of GCA were found in the occipital arteries which helped to confirm the diagnosis. One patient had already suffered significant visual loss by the time the diagnosis was made, reflecting the similarity in prognosis to the more typical GCA patients. These cases prompted a review of the literature to evaluate the evidence regarding the use of occipital artery ultrasonography in the investigation of GCA. We searched PubMed, Google Scholar and Web of Science and identified 17 papers but only four of these were relevant studies. The studies available show that typical features of GCA can be detected in the occipital arteries using ultrasonography. They also suggest that ultrasonography can detect changes in the occipital arteries when temporal arteries are not involved. However, occipital artery abnormalities were less common than temporal artery abnormalities in GCA. We advocate maintaining a high index of suspicion for GCA in patients presenting with atypical features, such as occipital headache. Ultrasonography has a vital role to play in the diagnosis of these patients. We recommend priority imaging of the affected area to facilitate prompt and accurate diagnosis of GCA, especially when atypical vessels are involved.

Contralateral posterior interhemispheric approach to deep medial parietooccipital vascular malformations: surgical technique and results.

OBJECTIVE Deep medial parietooccipital arteriovenous malformations (AVMs) and cerebral cavernous malformations (CCMs) are traditionally resected through an ipsilateral posterior interhemispheric approach (IPIA), which creates a deep, perpendicular perspective with limited access to the lateral margins of the lesion. The contralateral posterior interhemispheric approach (CPIA) flips the positioning, with the midline positioned horizontally for retraction due to gravity, but with the AVM on the upper side and the approach from the contralateral, lower side. The aim of this paper was to analyze whether the perpendicular angle of attack that is used in IPIA would convert to a parallel angle of attack with the CPIA, with less retraction, improved working angles, and no significant increase in risk. METHODS A retrospective review of pre- and postoperative clinical and radiographic data was performed in 8 patients who underwent a CPIA. RESULTS Three AVMs and 5 CCMs were resected using the CPIA, with an average nidus size of 2.3 cm and CCM diameter of 1.7 cm. All lesions were resected completely, as confirmed on postoperative catheter angiography or MRI. All patients had good neurological outcomes, with either stable or improved modified Rankin Scale scores at last follow-up. CONCLUSIONS The CPIA is a safe alternative approach to the IPIA for deep medial parietooccipital vascular malformations that extend 2 cm or more off the midline. Contralaterality and retraction due to gravity optimize the interhemispheric corridor, the surgical trajectory to the lesion, and the visualization of the lateral margin, without resection or retraction of adjacent normal cortex. Although the falx is a physical barrier to accessing the lesion, it stabilizes the ipsilateral hemisphere while gravity delivers the dissected lesion through the transfalcine window. Patient positioning, CSF drainage, venous preservation, and meticulous dissection of the deep margins are critical to the safety of this approach.

Stimulus-evoked changes in cerebral vessel diameter: A study in healthy humans.

The high metabolic demand of neuronal tissue, coupled with its relatively low energy storage capacity, requires that increases in neuronal activation are quickly matched with increased blood flow to ensure efficient supply of oxygen and nutrients to the tissue. For this to occur, dilation of nearby arterioles must be coordinated with the dilation of larger upstream feeding arteries. As it stands, the exact spatial extent of such dilation in humans is unknown. Using non-invasive time-of-flight magnetic resonance angiography in healthy participants, we developed an automatic methodology for reconstructing cerebral arterial vessels and quantifying their diameter on a voxel-by-voxel basis. Specifically, we isolated the posterior cerebral artery (PCA) supplying each occipital lobe and quantified its vasodilation induced by visual stimulation. Stimulus-induced changes were strongest (∼30%) near primary visual cortex and progressively decreased in a non-linear fashion as a function of distance. Surprisingly, weak - albeit significant - changes (∼2%) were observed ∼70 mm from the visual cortex. This demonstrates that visual stimulation modulates vascular tone along the bulk of the PCA segment, and thus may have important implications for our understanding of functional hyperemia in healthy and diseased states.

Neural predictors of emotional inertia in daily life.

Assessing emotional dynamics in the brain offers insight into the fundamental neural and psychological mechanisms underlying emotion. One such dynamic is emotional inertia-the influence of one's emotional state at one time point on one's emotional state at a subsequent time point. Emotion inertia reflects emotional rigidity and poor emotion regulation as evidenced by its relationship to depression and neuroticism. In this study, we assessed changes in cerebral blood flow (CBF) from before to after an emotional task and used these changes to predict stress, positive and negative emotional inertia in daily life events. Cerebral blood flow changes in the lateral prefrontal cortex (lPFC) predicted decreased non-specific emotional inertia, suggesting that the lPFC may feature a general inhibitory mechanism responsible for limiting the impact that an emotional state from one event has on the emotional state of a subsequent event. CBF changes in the ventromedial prefrontal cortex and lateral occipital cortex were associated with positive emotional inertia and negative/stress inertia, respectively. These data advance the blossoming literature on the temporal dynamics of emotion in the brain and on the use of neural indices to predict mental health-relevant behavior in daily life.

Occipital Microarteriovenous Malformation Resection, Strategy, and Nuances.

We describe a patient who presented with superior quadrianopsia due to an occipital micro AVM that bled into the optic radiation. Onyx embolization was attempted. However, early follow-up angiogram revealed recanalization and recurrence of the AVM. He was then taken to the hybrid operative room, where a complete resection was achieved confirmed by intraoperative angiogram. He made a complete recovery with no new neurologic deficit and stable visual field deficit. This case demonstrates treatment strategy, surgical planning, and technical nuances in microsurgical resection of micro AVMs located in an eloquent area. Management of a ruptured microarteriovenous malformation (microAVM) localized in an eloquent brain region is challenging. The major difficulties are those related to localizing and defining the micronidus in order to achieve complete resection and definitive cure while preserving function. The best and definitive treatment for AVMs is either surgical resection or radiosurgery. However, in our institute a small subset of microAVMs might be cured by endovascular embolization in a single session. In the case presented here, a single feeder was demonstrated and microcatheter navigation toward a good working position seemed feasible; thus we decided to try first an endovascular approach.

Etiology and Treatment Modalities of Occipital Artery Aneurysms.

BACKGROUND: Aneurysms of the external carotid artery represent approximately 2% of cervical carotid aneurysms, with the majority being traumatic pseudoaneurysms. Given the paucity of literature available for guidance, the diagnosis, treatment, and follow-up of such lesions are completely individualized. CASE DESCRIPTION: We report an 83-year-old woman with an 8-week history of headache in the occipital region, transient episode of gait disturbance, and pulsatile tinnitus on the right. She had no history of trauma, surgery, autoimmune disease, or infection. Physical examination revealed a pulsatile mass tender to palpation in the right occipital scalp. The mass was surgically excised, and histopathological diagnosis of a true aneurysm was made. Postoperatively, the patient's symptoms resolved; however, 1 month after the procedure, she developed occipital neuralgia, which was successfully treated with a percutaneous nerve block. CONCLUSIONS: To the best of our knowledge, this is the second reported case of a true aneurysm of the occipital artery in a patient with no history of trauma. The clinical examination, diagnosis, and treatment are discussed and the literature is reviewed for previously reported cases.