Extreme Lateral Transcondylar Approach Research Articles

C2 root nerve sheath tumors management

Upper cervical nerve sheath tumors (NST) arising mainly from C2 root and to lesser extent from C1 root are not uncommon, they constitute approximately 5-12% of spinal nerve sheath tumors and 18-30% of all cervical nerve sheath tumors, unique in presentation and their relationship to neighbouring structures owing to the discrete anatomy at the upper cervical-craniovertebral region, and have atendency for growth reaching large-sized tumors before manifesting clinically due to the capacious spinal canal at this region; accordingly the surgical approaches to such tumors are modified. The aim of this paper is to discuss the surgical strategies for upper cervical nerve sheath tumors. Eleven patients (8 male and 3 females), age range 28-63 years, with C2 root nerve sheath tumors were operated upon based on their anatomical relations to the spinal cord. The magnetic resonance imaging findings were utilized to determine the surgical approach. The tumors had extra- and intradural components in 10 patients, while in one the tumor was purely intradural. The operative approaches included varied from extreme lateral transcondylar approach(n = 1) to laminectomy, whether complete(n = 3) a or hemilaminectomy(n = 7), with partial facetectomy(n = 7), and with suboccipital craniectomy(n = 2). The clinical picture ranged from spasticity (n = 8, 72,72 %), tingling and numbness below neck (n = 6, 54,54 %), weakness (n = 6, 54,54 %), posterior column involvement (n = 4, 26,36 %), and neck pain (n = 4, 36,36 %). The duration of symptoms ranged from 1 to 54 months, total excision was performed in 7 patients; while in 3 patients an extraspinal component, and in 1 patient a small intradural component, were left in situ. Eight patients showed improvement of myelopathy; 2 patients maintained their grades. One poor-grade patient was deteriorated. The surgical approaches for the C2 root nerve sheath tumors should be tailored according to the relationship to the spinal cord, determined by magnetic resonance imaging.

Extreme lateral transcondylar approach for resection of ventrally based meningioma of the craniovertebral junction and upper cervical spine.

Ventrally based meningiomas at the craniovertebral junction can be challenging tumors to remove because of their deep location anterior to the lower brainstem and upper cervical spinal cord, and close association with complex neurovascular structures. The extreme lateral transcondylar approach provides excellent access and exposure to anterior and anterolateral intradural tumors involving the region of the craniovertebral junction, including the lower third of the clivus, the foramen magnum, and the upper cervical spine. This approach allows safe access for removal of these difficult tumors without any neural retraction. In this operative video manuscript, the author demonstrates an illustrative step-by-step technique for microsurgical resection of a ventrally based meningioma extending from the foramen magnum to C-2 using the extreme lateral transcondylar approach. The operative technique and surgical nuances, including the surgical approach, intradural tumor removal, and cranial base reconstruction, are illustrated in this video atlas. The video can be found here: http://youtu.be/4uvPpEtEShU .

Postauricular, transpetrous, presigmoid approach for extensive skull base tumors in the petroclival region: the successes and the travails

Postauricular, transpetrous, presigmoid approach combines a supra/infratentorial exposure with partial petrosectomy to access third to the twelfth cranial nerves and extraaxial lesions situated anterolateral to brainstem. It provides a shorter working distance to large petrosal, petroclival, cerebellopontine, and cerebellomedullary cisternal lesions and their extensions to the subtemporal-infratemporal areas. This study reviews the surgical technique, corridors of extension, and complications encountered utilizing this approach for excising extensive lesions in these locations. The lesions (n = 14) included petroclival meningiomas [(n = 5), including three recurrent lesions], dumbbell lower cranial nerve schwannomas (n = 2), giant acoustic schwannomas (n = 2), recurrent giant trigeminal nerve schwannoma (n = 1), glomus jugulare (n = 3), and recurrent petrous aneurysmal bone cyst (n = 1). The approach was combined with a retrosigmoid suboccipital craniectomy (n = 3), with an infratemporal approach (n = 2), and with an extreme lateral transcondylar approach and a translabyrinthine approach in one patient each, respectively. External auditory canal was not ligated in nine patients, superior petrosal sinus and tentorial division was performed in all patients, and sigmoid sinus-internal jugular vein was excised in three patients (with a glomus jugulare (n = 1) and petroclival meningioma (n = 2), respectively). Repair was performed with fat-fascia, pedicled pericranium, and temporalis muscle. Lumbar drain was placed for three to five postoperative days. Total excision was performed in nine patients. Small tumor remnants were left attached to the brainstem (n = 3, petroclival meningioma), carotid canal and cavernous sinus (n = 1, glomus jugulare), and sigmoid sinus-jugular bulb (n = 1, recurrent trigeminal schwannoma). A two-staged procedure was performed in three patients. Two patients with recurrent giant petroclival meningiomas died: one with lower cranial nerve paresis due to aspiration pneumonitis and the other with cerebrospinal fluid otorrhoea and secondary meningitis. The approach facilitates direct tumor decompression and its retraction away from the brainstem without initially encountering the intracisternal cranial nerves and neuraxis. It provides multiple corridors for excising extensive posterior fossa tumors. Preoperative assessment of sigmoid sinus dominance, jugular bulb height, labyrinth, vein of Labbe, and space available through Trautman's triangle considerably helps in complication avoidance.

Surgical treatment of clival chordomas

IntroductionClival chordomas are benign neoplastic tumours displaying high morbidity and mortality rates. The difficulties involved in obtaining a total resection and its infiltrative nature explain this aggressiveness. Materials and methodWe present a retrospective clinical series of 8 cases of clival chordomas treated surgically at our department from 1993 to 2006. ResultsAll 8 patients underwent a total of 14 surgical procedures, 6 of which were anterior approaches (5 transmandibular), 2 subtemporal-preauricular, 2 from the extreme lateral transcondylar and 2 transcochlear. In 7 patients, the surgery was performed with curative intent. In 2 cases, it was necessary to perform the surgery sequentially, in two steps. Total resection was achieved in 58% of patients. Average follow up was 40 months. Two patients died due to local recurrence, one patient died in the postoperative period and another died due to causes not related with the tumour. DiscussionThe low incidence of clival chordomas makes it difficult to carry out random clinical studies of its management. The treatment of choice is surgery, supplemented by radiotherapy in selected cases. We prefer the transmandibular approach, combined with extreme lateral transcondylar approach when the occipital condyle is infiltrated. For lateral extensions, we use the subtemporal-preauricular or transpetrosal approaches. New radiotherapy modalities provide an effective treatment of tumour residues. ConclusionsExtradural approaches imply anatomical regions familiar for otolaryngologists. Specific knowledge about the limitations of each approach is essential to avoid unnecessary morbidity and incomplete resections.

Surgery of Craniocervical Meningiomas

Objective: To study the different surgical approaches to craniocervical meningiomas in different locations in the area of the foramen magnum, whether anterior, posterior, antrolateral or posterolateral Methods: Twenty six patients with craniocervical meningiomas were operated upon during the period from 2000 to 2009 using the standard posterior approach for posterior lesions (14 cases), extreme lateral approach without drilling of the occipital condyle in the antrolateral and posterolateral lesions(6 cases) and transcondylar approach for anterior lesions (6 cases). Results: This study included 16 females and 10 males, the patients’ age ranged from 23 to 64 years with a mean of 51.8 years. Tumor size ranged from2 to 6.4 in its maximum diameter. Tumor location was posterior in 14 patients, lateral in 6 patients and anterior in 6 patients. Total tumor resection was done in 23 (88.4%) patients and subtotal in 3 (11.6%) patients. Postoperative complications included transient lower cranial nerves affection, transient hemiparesis. There was no mortality in this study. The follow up period ranged from 6 months to 4.8 years. Conclusion: Surgical approach to craniocervical meningioma has to be tailored according to the location of the tumor. Posterior tumors are safely totally removed through the slandered suboccipital approach. Posterolateral and antrolateral tumors are easily removed via the postero lateral retrocondylar approach without drilling of the occipital condyle benefiting from the working space given by lateral displacement of the brain stem. Anteriorly located tumors are better approached through the extreme lateral transcondylar approach to avoid brain stem retraction. Key words: Foramen magnum, meningioma, occipital condyle, suboccipital approach.

Anatomical basis of approaches to foramen magnum and lower clival meningiomas: comparison of retrosigmoid and transcondylar approaches

Meningiomas of the lower clivus and foramen magnum are among the most challenging of all neurosurgical lesions. Debate continues regarding the most appropriate approach to this eloquent anatomical region. This anatomical study was undertaken to measure and compare the area of surgical exposures of the lower clivus achieved using the retrosigmoid and the extreme-lateral transcondylar (ELT) approaches. Thirteen embalmed cadaveric heads were dissected bilaterally via the retrosigmoid approach on one side and the ELT approach on the other. The circumference of the area of exposure was delineated using beaded pins placed into the dura. After removal of the brain, the longest longitudinal and transverse axes of the pinned areas were measured and surface area calculated. The area of surgical exposure was also expressed as a percentage of the total area of the lower clivus. Normalized and adjusted surface areas were calculated using the bimastoid diameter. The areas of exposure were compared using the two-tailed paired Student t-test. The mean area of exposure required using the retrosigmoid approach was 19.8 +/- 14.7 mm2 (range 6-49 mm2) and that using the ELT approach was 27.8 +/- 22.8 mm2 (range 10-90 mm2). The mean percentage of the lower clivus exposed by the retrosigmoid approach was 14.9 +/- 3.6% (range 10-22%) and that exposed by the ELT approach was 20.5 +/- 4.9% (range 10-25%). The ELT approach provided significantly greater area of operative exposure and allowed a significantly higher percentage of lower clivus and foramen magnum exposure than did the retrosigmoid approach (p < 0.05). Normalized and adjusted surface areas, taking into consideration the bimastoid diameter, were also statistically significant in favor of the ELT approach. The ELT approach provided a significantly greater area of exposure than did the retrosigmoid approach.

Intermittent vertebral artery compression caused by C1-root schwannoma: Case Report

Extradural schwannomas of the Cl-root are extremely rare. As the tumor grows in size, it may compress surrounding neurovascular structures and cause symptoms. In the present case report, the left vertebral artery (VA) was severely compressed by the tumor, eliciting severe vertigo on turning the head to the right side and with neck extension. We report a 52-year-old man who presented with a history of intermittent episodes of severe vertigo on head movement that was caused by a Cl-root schwannoma. The lesion was exposed through an extreme lateral transcondylar approach. At exposure the lesion was yellowish in color and was extradural in location lying between the markedly eroded Cl -posterior arch and the compressed vertebral artery (V3) on the leftside. The medial portion of the tumor was attached to the Cl-nerve root. The tumor was excised enbloc with decompression of the VA. The patient’s symptoms completely resolved immediately following surgery, with no recurrence of the symptoms at one year follow up. The vertebral artery may frequently be compressed by osteophytes in cervical spondylosis or due to other causes in the cervical spinal canal, but compression of the artery by Cl extradural schwannoma with vascular insufficiency is rare. Remove! of the tumor and the resultant decompression of the artery can be facilitated by the extreme lateral approach as demonstrated by this case. [Neurol 2000; 22: 679-684]

Occipitocervical fusion following the extreme lateral transcondylar approach

BACKGROUND Modern cranial base approaches to the clivus and foramen magnum may threaten the stability of the cranio-cervical junction. This necessitates stabilization and fusion in some cases. We studied occipitocervical fusion after extreme lateral transcondylar approaches. METHODS Twenty-seven patients underwent an extreme lateral transcondylar approach over a 2-year period. Two patients were excluded because of prior occipitocervical fusion. The pathological diagnosis was meningioma in ten patients, chordoma in six patients, neurofibroma in two, and 10 patients had other tumoral and nontumoral pathologies. RESULTS Eight patients required occipitocervical fusion and stabilization. Five of six patients with chordomas required fusion, whereas no patient with a meningioma underwent fusion. All the patients who were fused had more than 70% resection of their occipital condyle. No patient with resection of less than 70% of the occipital condyle required fusion. Significant interference of the surgical construct with follow-up imaging was seen only in the patient in whom a stainless steel Steinman pin was used. CONCLUSION One third of patients will require fusion after extreme lateral transcondylar approaches. Most patients with less than 70% resection of the condyle remain stable without need for surgical intervention, whereas complete resection necessitates fusion in most cases.

Surgical anatomy and morphometric analysis of the occipital condyles and foramen magnum.

Surgical anatomy that provides the basis for dealing with lesions arising in the lower clivus and ventral foramen magnum was reviewed in 8 adult cadaver heads and 76 dry skulls. The extreme lateral transcondylar approach was performed in cadavers; the morphometric analysis was studied in both the cadavers and the skulls. The landmarks, distances and structures were selected in order to guide the surgical operations in this area. In the paper, surgical approaches to this region are reviewed, and the results are discussed from the standpoint of surgical importance.

P-5-664 - Postoperative course of extracerebral infratentorial tumors

Vertebral artery (VA) transposition in the extreme-lateral transcondylar approach can minimize the manipulation of the low cranial nerves and the brain stem. The authors describe the surgical technique of VA transposition.From March 2000 to December 2014, 28 of 48 patients underwent VA transposition for anterior foramen magnum meningioma (16 patients) and craniocervical junction (CCJ) tumors (12 patients). Tumor was resected via an extreme-lateral approach with partial condylectomy to expose the anterior portion of the brain stem. For intradural tumors, the VA was mobilized caudomedially after circumferential dural incision around the VA at the level of the foramen magnum. For extradural tumors involving the CCJ, VA was transposed medially from the transverse foramen of C1 without any dural incision.Gross total resection was achieved in 26 of 28 patients (92.9%) with VA transposition. Histologically, meningioma and schwannoma were most common. The origin of the tumors was foramen magnum (57.1%), C1 nerve root (17.9%), clivus (10.7%), jugular foramen (7.1%), posterior skull base (3.6%), and hypoglossal canal (3.6%). VA transposition was performed intradurally in 19 patients (67.9%) and extradurally in 9 patients (32.1%). Surgical morbidity was 17.9% including 4 patients with hypoglossal nerve palsy and 1 patient with quadriparesis. The mean follow-up duration after surgery was 4.2 years (range, 0.1–14.8 years).VA transposition can provide a wide surgical window for anterior foramen magnum meningioma or tumors involving the CCJ with the least manipulation of the neuraxis.

P-5-665 - A case of aneurysmal bone cyst with cranial expansion

Vertebral artery (VA) transposition in the extreme-lateral transcondylar approach can minimize the manipulation of the low cranial nerves and the brain stem. The authors describe the surgical technique of VA transposition.From March 2000 to December 2014, 28 of 48 patients underwent VA transposition for anterior foramen magnum meningioma (16 patients) and craniocervical junction (CCJ) tumors (12 patients). Tumor was resected via an extreme-lateral approach with partial condylectomy to expose the anterior portion of the brain stem. For intradural tumors, the VA was mobilized caudomedially after circumferential dural incision around the VA at the level of the foramen magnum. For extradural tumors involving the CCJ, VA was transposed medially from the transverse foramen of C1 without any dural incision.Gross total resection was achieved in 26 of 28 patients (92.9%) with VA transposition. Histologically, meningioma and schwannoma were most common. The origin of the tumors was foramen magnum (57.1%), C1 nerve root (17.9%), clivus (10.7%), jugular foramen (7.1%), posterior skull base (3.6%), and hypoglossal canal (3.6%). VA transposition was performed intradurally in 19 patients (67.9%) and extradurally in 9 patients (32.1%). Surgical morbidity was 17.9% including 4 patients with hypoglossal nerve palsy and 1 patient with quadriparesis. The mean follow-up duration after surgery was 4.2 years (range, 0.1–14.8 years).VA transposition can provide a wide surgical window for anterior foramen magnum meningioma or tumors involving the CCJ with the least manipulation of the neuraxis.

The Extreme Lateral Transcondylar Approach to Aneurysms of the Vertebrobasilar Junction, the Vertebral Artery, and the Posterior Inferior Cerebellar Artery

The unilateral suboccipital craniotomy is the commonly performed approach to aneurysms of the vertebrobasilar junction, the vertebral artery, and the posterior inferior cerebellar artery (PICA). Many of these aneurysms are placed anterior or anterolateral to the brain stem, necessitating brain stem retraction for adequate exposure. Small dorsolateral enlargement of the foramen magnum, partial resection of the occipital condyle, and removal of the jugular tubercle allow access to the neurovascular structures ventral to the medulla without retraction of the neuroaxis. This extreme lateral transcondylar approach was performed in 20 patients with aneurysms of the vertebrobasilar junction, the vertebral artery, and the PICA; intraoperatively, two suspected aneurysms proved to be vascular malformations. Occlusion of the aneurysm and vascular malformation was successfully performed in 16 patients, resection of the vascular malformation was achieved in 1 patient, and the vertebral artery was clipped in 3 patients with fusiform aneurysms without complications related to the extreme lateral transcondylar approach. Unobstructed exposure of the aneurysm, parent artery, and neural structures without retraction of the sensitive lower brain stem are the major advantages of the extreme lateral transcondylar approach.