Histology of the vertebral artery–dural junction: relevance to posterolateral approaches to the skull base

2019 ◽  
pp. 1-6
Author(s):  
Robert C. Rennert ◽  
Martin P. Powers ◽  
Jeffrey A. Steinberg ◽  
Takanori Fukushima ◽  
John D. Day ◽  
...  

OBJECTIVEThe far-lateral and extreme-lateral infrajugular transcondylar–transtubercular exposure (ELITE) and extreme-lateral transcondylar transodontoid (ELTO) approaches provide access to lesions of the foramen magnum, inferolateral to mid-clivus, and ventral pons and medulla. A subset of pathologies in this region require manipulation of the vertebral artery (VA)–dural interface. Although a cuff of dura is commonly left on the VA to avoid vessel injury during these approaches, there are varying descriptions of the degree of VA-dural separation that is safely achievable. In this paper the authors provide a detailed histological analysis of the VA-dural junction to guide microsurgical technique for posterolateral skull base approaches.METHODSAn ELITE approach was performed on 6 preserved adult cadaveric specimens. The VA-dural entry site was resected, processed for histological analysis, and qualitatively assessed by a neuropathologist.RESULTSHistological analysis demonstrated a clear delineation between the intima and media of the VA in all specimens. No clear plane was identified between the connective tissue of the dura and the connective tissue of the VA adventitia.CONCLUSIONSThe VA forms a contiguous plane with the connective tissue of the dura at its dural entry site. When performing posterolateral skull base approaches requiring manipulation of the VA-dural interface, maintenance of a dural cuff on the VA is critical to minimize the risk of vascular injury.

2011 ◽  
Vol 69 (suppl_1) ◽  
pp. ons103-ons116 ◽  
Author(s):  
Vittorio M. Russo ◽  
Francesca Graziano ◽  
Antonino Russo ◽  
Erminia Albanese ◽  
Arthur J. Ulm

Abstract BACKGROUND: Surgical exposure of lesions located along the ventral foramen magnum (FM) and clivus poses a unique set of challenges to neurosurgeons. Several approaches have been developed to access these regions with varying degrees of exposure and approach-related morbidity. OBJECTIVE: To describe the microsurgical anatomy of the high anterior cervical approach to the clivus and foramen magnum, and describe novel skull base extensions of the approach. METHODS: Eight adult cadaveric specimens were included in this study. The high anterior cervical approach includes a minimal anterior clivectomy and its lateral skull base extensions: the extended anterior far-lateral clivectomy and the inferior petrosectomy. The microsurgical anatomy and exposure of the various extensions of the approach were analyzed. In addition, the capability of complementary endoscopy was evaluated. RESULTS: With proper positioning, the minimal anterior clivectomy exposed the vertebrobasilar junction, proximal basilar artery, anteroinferior cerebellar arteries, and 6th cranial nerve. The lateral skull base extensions provided access to the anterior FM, mid-lower clivus, and petroclival region, up to the Meckel cave, contralateral to the side of the surgical approach. CONCLUSION: The high anterior cervical approach with skull base extensions is an alternative to the classic approaches to the ventral FM and mid-lower clivus. A minimal anterior clivectomy provides access to the midline mid-lower clivus. The addition of an extended anterior far-lateral clivectomy and an inferior petrosectomy extends the exposure to the anterior FM and cerebellopontine angle lying anterior to the cranial nerves. The approach is also ideally suited for endoscopic-assisted techniques.


2019 ◽  
Vol 80 (S 04) ◽  
pp. S360-S362
Author(s):  
Sima Sayyahmelli ◽  
Mustafa K. Başkaya

Foramen magnum meningiomas are one of the most challenging tumors for skull base neurosurgeons due to their proximity to critical neurovascular structures. The far-lateral approach demonstrated here facilitates access to lesions involving the anterior portion of the foramen magnum.In this video, we present a 62-year-old woman with hand numbness and weakness. The patient had significant difficulty in fine motor movements of both hands. In the neurological examination, she had a significant right-hand intrinsic muscle weakness and mild quadriparesis.Magnetic resonance imaging (MRI) showed a dural-based homogeneously enhancing extra-axial mass in the anterior foramen magnum with a significant mass effect on the brain stem and the upper cervical cord. The decision was made to proceed with a far lateral transcondylar skull base approach including partial C1 laminectomy.The surgery and postoperative course were uneventful. The postoperative MRI showed gross total resection of the mass. The histopathology indicated a WHO (World health Organization) grade-I meningioma. The patient's postoperative course was uneventful. She improved to normal neurological function within several weeks and continues to do well without recurrence at 20 months' follow-up.In this video, we demonstrated important steps for the microsurgical resection of these challenging lesions.The link to the video can be found at: https://youtu.be/_nuX2Y7YU9w.


2019 ◽  
Vol 80 (S 04) ◽  
pp. S363-S364
Author(s):  
Ciro Vasquez ◽  
Alexander Yang ◽  
A. Samy Youssef

We present a case of a foramen magnum meningioma in a 42-year-old female who presented with headaches for 2 years, associated with decreased sensation and overall feeling of “heaviness” of the right arm. The tumor posed significant mass effect on the brainstem, and given the location of the tumor in the anterolateral region of the foramen magnum, a right far lateral approach was chosen. The approach incorporates the interfascial dissection technique to safely expose and preserve the vertebral artery in the suboccipital triangle. After drilling the posteromedial portion of the occipital condyle and opening the dura, the tumor can be entirely exposed with minimal retraction on the cerebellum. The working space offered by the far lateral approach allows careful dissection at the lateral craniocervical junction, and preservation of the V4 segment of the vertebral artery and the lower cranial nerves. Simpson's grade-2 resection was achieved with coagulation of the dural base around the vertebral artery. The postoperative course was unremarkable for any neurological deficits. At the 2-year follow-up, imaging identified no recurrence of tumor and the patient remains asymptomatic.The link to the video can be found at: https://youtu.be/IMN1O7vO5B0.


2013 ◽  
Vol 35 (6) ◽  
pp. E12 ◽  
Author(s):  
Bruno C. Flores ◽  
Benjamin P. Boudreaux ◽  
Daniel R. Klinger ◽  
Bruce E. Mickey ◽  
Samuel L. Barnett

Foramen magnum meningiomas (FMMs) are slow growing, most often intradural and extramedullary tumors that pose significant challenges to the skull base neurosurgeon. The indolent clinical course of FMMs and their insidious onset of symptoms are important factors that contribute to delayed diagnosis and relative large size at the time of presentation. Symptoms are often produced by compression of surrounding structures (such as the medulla oblongata, upper cervical spinal cord, lower cranial nerves, and vertebral artery) within a critically confined space. Since the initial pathological description of a FMM in 1872, various surgical approaches have been described with the aim of achieving radical tumor resection. The surgical treatment of FMMs has evolved considerably over the last 4 decades due to the progress in microsurgical techniques and development of a multitude of skull base approaches. Posterior and posterolateral FMMs can be safely resected via a standard midline suboccipital approach. However, controversy still exits regarding the optimal management of anterior or anterolateral lesions. Independently of technical variations and the degree of bone removal, all modern surgical approaches to the lower clivus and anterior foramen magnum derive from the posterolateral (or far-lateral) craniotomy originally described by Roberto Heros and Bernard George. This paper is a review of the surgical management of FMMs, with emphasis on the far-lateral approach and its variations. Clinical presentation, imaging findings, important neuroanatomical correlations, recurrence rates, and outcomes are discussed.


2018 ◽  
Vol 16 (4) ◽  
pp. E130-E133
Author(s):  
Derek G Southwell ◽  
Jonathan D Breshears ◽  
William R Lyon ◽  
Michael W McDermott

Abstract BACKGROUND AND IMPORTANCE Skull base surgery involves the microdissection and intraoperative monitoring of cranial nerves, including cranial nerve XI (CN XI). Manipulation of CN XI can evoke brisk trapezius contraction, which in turn may disturb the surgical procedure and risk patient safety. Here we describe a method for temporarily silencing CN XI via direct intraoperative application of 1% lidocaine. CLINICAL PRESENTATION A 41-yr-old woman presented with symptoms of elevated intracranial pressure and obstructive hydrocephalus secondary to a hemangioblastoma of the right cerebellar tonsil. A far-lateral suboccipital craniotomy was performed for resection of the lesion. During the initial stages of microdissection, vigorous trapezius contraction compromised the course of the operation. Following exposure of the cranial and cervical portions of CN XI, lidocaine was applied to the course of the exposed nerve. Within 3 min, trapezius electromyography demonstrated neuromuscular silencing, and further manipulation of CN XI did not cause shoulder movements. Approximately 30 min after lidocaine application, trapezius contractions returned, and lidocaine was again applied to re-silence CN XI. Gross total resection of the hemangioblastoma was performed during periods of CN XI inactivation, when trapezius contractions were absent. CONCLUSION Direct application of lidocaine to CN XI temporarily silenced neuromuscular activity and prevented unwanted trapezius contraction during skull base microsurgery. This method improved operative safety and efficiency by significantly reducing patient movement due to the unavoidable manipulation of CN XI.


2009 ◽  
Vol 11 (1) ◽  
pp. 84-87 ◽  
Author(s):  
R. Shane Tubbs ◽  
Nemil A. Shah ◽  
Brian P. Sullivan ◽  
Nicholas D. Marchase ◽  
Aaron A. Cohen-Gadol

Object The vertebral artery (VA) and its branches may be encountered during various neurosurgical procedures such as far lateral suboccipital approaches to the skull base and spinal operations. Therefore, a working knowledge of the distribution and significance of such VA branches may be advantageous to the surgeon. To date, quantitation of these branches is lacking in the literature. Methods The authors evaluated the branches of 20 VAs from 10 adult cadavers and assessed the distribution and surgical significance of the branches from the V2 and V3 segments. Results In terms of target tissues, the VA branches encountered at the C1–2 level were most likely to be muscular, branches at C2–3 osseous, and those at C3–6 radicular. No radicular or medullary branches were identified arising from any V3 segment of the VA or C1–2 level of the V2 segment. The greatest concentration of branches per level was found arising from the V2 segment at C2–3. Posterior branches of the VA tended to be radicular or muscular, whereas anterior branches tended to be radicular or osseous. Lateral branches were most commonly radicular and medial branches tended to be osseous or muscular in nature. The largest branches of the VA originated from its V3 segment or the C2–3 part of its V2 segment. Rarely, branches to the extracranial glossopharyngeal and spinal accessory nerves were identified originating from the V3 and V2 segments of the VA, respectively. Conclusions Although seemingly diverse in their distribution, the branches of the V2 and V3 segments of the VA may follow a certain consistent arrangement. The potential for injury to neural branches of the VA is minimal at its V3 segment and the C1–2 portion of its V2 segment. Such knowledge may be of use to the neurosurgeon who operates in the neck and at the craniocervical junction.


Author(s):  
James K. Liu ◽  
Vincent N. Dodson ◽  
Ali T. Meybodi

AbstractSurgical access to the ventral foramen magnum remains a technical challenge. With large lesions in this region compressing the brainstem and distorting the regional neurovascular relationships, formulating a surgical plan and its appropriate execution have crucial importance in achieving favorable outcomes. While the endoscopic endonasal approaches have gained increasing attention to access the clivus and the ventral brainstem, foramen magnum meningiomas are still preferred to be removed via an approach that obviates a trajectory through the nasopharyngeal mucosa. Therefore, the far lateral approach remains one of the most practical approaches for these challenging lesions. This operative video demonstrates the use of the far lateral transcondylar transtubercular approach to remove a large meningioma in the ventral foramen magnum in a 63-year-old male with progressive cervical myelopathy, presenting as spastic quadriparesis without any cranial nerve abnormality. Using a right-sided far lateral transcondylar transtubercular approach, the meningioma was exposed within the cerebellomedullary gutter engulfing the vertebral artery and distorting the course of the adjacent cranial nerves. Using the different corridors identified between the vertebral artery, spinal accessory, vagus, and hypoglossal nerves, multiple angles of attacks to the tumor were established and utilized to resect the lesion. A gross total resection was achieved and the patient was neurologically intact without any neurological deficits. This video demonstrates the importance of understanding the intricacies of neurovascular anatomy of the cervicomedullary region (i.e., the various triangles formed between these structures), and the effective use of these corridors to safely and efficiently remove a challenging ventral foramen magnum meningioma with neurovascular involvement, while preserving cranial nerve function. The surgical technique and nuances are described in a step-by-step fashion in this illustrative operative video.The link to the video can be found at: https://youtu.be/s1dFhuaRSt8.


Author(s):  
Panduranga Seetahal-Maraj

Tumours of the foramen magnum are infrequent compared to other locations within the neuraxis. Meningiomas are one of the most frequently encountered tumours of the nervous system, but only 1.8 to 3.2% actually originate within the foramen magnum. However, they account for almost 50% of all tumours in this region. We report a case of a large foramen magnum meningioma in a 16-year-old female, the diagnostic difficulty it presents due to its rarity and indolent course, and the surgical strategies employed to manage this case. This was the first performance of a far-lateral craniotomy in San Fernando General Hospital. The use of a staged procedure to facilitate this skull base tumour resection resulted in an excellent outcome.


2019 ◽  
Vol 24 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Robert C. Rennert ◽  
Reid Hoshide ◽  
Michael G. Brandel ◽  
Jeffrey A. Steinberg ◽  
Joel R. Martin ◽  
...  

OBJECTIVELesions of the foramen magnum, inferolateral-to-midclival areas, and ventral pons and medulla are often treated using a far-lateral or extreme-lateral infrajugular transcondylar–transtubercular exposure (ELITE) approach. The development and surgical relevance of critical posterior skull base bony structures encountered during these approaches, including the occipital condyle (OC), hypoglossal canal (HGC), and jugular tubercle (JT), are nonetheless poorly defined in the pediatric population.METHODSMeasurements from high-resolution CT scans were made of the relevant posterior skull base anatomy (HGC depth from posterior edge of the OC, OC and JT dimensions) from 60 patients (evenly distributed among ages 0–3, 4–7, 8–11, 12–15, 16–18, and > 18 years), and compared between laterality, sex, and age groups by using t-tests and linear regression.RESULTSThere were no significant differences in posterior skull base parameters by laterality, and HGC depth and JT size did not differ by sex. The OC area was significantly larger in males versus females (174.3 vs 152.2 mm2; p = 0.01). From ages 0–3 years to adult, the mean HGC depth increased 27% (from 9.0 to 11.4 mm) and the OC area increased 52% (from 121.4 to 184.0 mm2). The majority of growth for these parameters occurred between the 0–3 year and 4–7 year age groups. Conversely, JT volume increased nearly 3-fold (281%) from 97.4 to 370.9 mm3 from ages 0–3 years to adult, with two periods of substantial growth seen between the 0–3 to 4–7 year and the 12–15 to 16–18 year age groups. Overall, JT growth during pediatric development was significantly greater than increases in HGC depth and OC area (p < 0.05). JT volume remained < 65% of adult size up to age 16.CONCLUSIONSWhen considering a far-lateral or ELITE approach in pediatric patients, standard OC drilling is likely to be needed due to the relative stability of OC and HGC anatomy during development. The JT significantly increases in size with development, yet is only likely to need to be drilled in older children (> 16 years) and adults.


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