Tailored Surgical Approaches for Foramem Magnum Tumors

Objective To describe our surgical techniques, analyze their safety and their postoperative outcomes for foramen magnum tumors (FMTs). Methods From 1986 to 2014, 34 patients with FMTs underwent surgeries using either the lateral suboccipital approach, standard midline suboccipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions. Results In the present series, there were 22 (64.7%) female and 12 (35.2%)male patients. The age of the patients ranged from12 to 63 years old.We observed 1 operativemortality (2.9%). A total of 28 patients (82.3%) achieved a score of 4 or 5 in the Glasgow Outcome Scale (GOS). Gross total resection (GTR) was obtained in 22 (64.7%) patients. After the surgery, 9 (26%) patients developed lower cranial nerve dysfunction (LCNd) weakness. The follow-up varied from 1 to 24 years (mean: 13.2 years). Conclusion Themajority of tumors located in the FMcan be safely and efficiently removed usingeither thelateral suboccipital approach, standardmiddlelinesuboccipital craniotomy, or the far lateral approach, depending on the anatomic location of the lesions.

Far lateral approach for intradural tumors at the craniocervical junction

Ventrally placed tumors at the cranio-cervical junctions is a challenging neurosurgical task. The most important factor that influences the surgical outcome in foramen magnum lesions is comprehensive and three-dimensional understanding of the specific anatomy of the region. This study describes in details the far lateral approach for intradural tumors in the craniocervical region, with special emphasis on the management of the vertebral artery and on the anatomic variations encountered in this region. Patients The study included 28 patients with different tumor pathologies in the lateral foramen magnum. All were operated using the far lateral approach to access the lateral angle of the foramen magnum after mobilizing the vertebral artery. The study included 15 cases of ventrally placed meningiomas at the foramen magnum, 7 patients with intra-axial brainstem gliomas, and 6 patients with lower cranial nerve schwanoma. Total excision was achieved in 15 patients, whereas subtotal resection was achieved in thirteen cases. The study included three cases of CSF leakage; one of which needed a secondary dural repair with contimous lumbar drainage. One patient suffered intradural vertebral artery injury in a recurrent meningioma which led to serious morbidity postoperative. Far lateral approach can provide a good working angle to the anterior of the brainstem without extra drilling of the occipital condyle, the aim of surgery at the foramen magnum should be directed at brainstem decompression rather than unsafe total excision of the tumor

Downbeating nystagmus and postural hypotension due to basilar invagination.

Downbeating nystagmus is an involuntary vertical rhythmic eye movement with the fast component in the downward direction. The sign indicates a craniocervical disorder. The most common cause is the Arnold-Chiari malformation, followed by cerebellar degeneration. Basilar invagination is a rare cause of downbeating nystagmus. However, with appropriate treatment its prognosis is good. Here, we report a case of basilar invagination which presented with downbeating nystagmus and postural hypotension. A 31 year-old Thai male patient had a 20 year history of postural hypotension. He had recurrent pneumonia and cough-induced syncope a year before admission. He complained of symptoms of an acute febrile illness and a productive cough. The physical examination showed high grade fever, postural hypotension and medium crepitation in the right upper lobe. The neurological examination showed downbeating nystagmus, atrophy and fasciculation of the right side of the tongue, atrophy of the right sternocleidomastoid muscle, mild weakness of the extremities and generalized hyperreflexia. The cervical spine X-ray revealed upward displacement of the vertebral bodies of C1 and C2, with a mild narrowing of the space between C1 and the occiput. The CT-myelogram and MRI showed upward displacement of C1 with overriding of the dens over the anterior lip of the foramen magnum; this also compressed the medulla. Syringomyelia was seen at the C1-C5 level. We report a patient who presented with postural hypotension, recurrent pneumonia and downbeating nystagmus due to basilar invagination. The symptoms were aggravated by cough which caused an increase in intracranial pressure. This resulted from medulla compression in the foramen magnum by the first cervical spine. The treatment of choice was surgical decompression.