Search Results

You are looking at 1 - 10 of 61 items for

  • Author or Editor: Arnold H. Menezes x
Clear All Modify Search
Restricted access

Arnold H. Menezes

Object

Hindbrain herniation syndrome, or Chiari malformation Type I (CM-I), occurs frequently with craniovertebral junction (CVJ) abnormalities when there is reduction in the posterior fossa volume. Syringomyelia is often present. Posterior fossa dorsal decompression (PFDD) is typically performed but has adverse results when ventral bone abnormality exists. This paper presents the results of a prospective study on CVJ abnormalities in patients with CM-I and syringomyelia.

Methods

Between 1984 and 2008 (the MR imaging era), 298 patients with CVJ abnormalities and CM-I underwent ventral cervicomedullary decompression. Eighty-four patients had associated syringomyelia (15 with secondary invagination and 69 with primary basilar invagination, os odontoideum, or malunion of fractures). Of these 84 patients with CVJ abnormalities, CM-I, and syringomyelia, 46 had previously undergone PFDD, and 28 had previously undergone PFDD combined with fusion procedures or shunt placements. Of the 84 patients, a cervicothoracic syrinx was observed in 57, thoracic syrinx in 14, and holocord syrinx in 13. Studies included CT, MR imaging, and cine flow studies. All 298 patients who underwent ventral CVJ decompression had irreducible or partially reducible pathology. All 84 with syringomyelia showed brainstem dysfunction, lower cranial nerve symptoms, or myelopathy.

Results

Brainstem signs improved in 66 of the 84 patients, myelopathy improved in 58, and syringomyelia regressed in 64.

Conclusions

Neurological improvement and syringomyelia resolution can occur using only ventral cervicomedullary junction decompression in patients with basilar invagination and basilar impression. This is likely due to the relief of neural encroachment and reestablishment of CSF pathways.

Restricted access

Arnold H. Menezes

The surgical management of craniovertebral junction (CVJ) instability in pediatric patients presents unique challenges. As compared with the adult patient, the anatomical variations of the CVJ in the pediatric patient are significant, complicate the approach, and limit the use of internal fixation. Diminutive osseous and ligamentous structures and syndromic craniovertebral abnormalities complicate the issue. Advances in imaging analysis and instrumentation have improved the armamentarium for managing the pediatric patient who requires craniocervical stabilization. In this paper, the author's experience of performing more than 850 pediatric CVJ fusions is reviewed. This work includes the indications for atlantoaxial arthrodesis and occipitocervical fusion. Early atlantoaxial fusions were performed using interlaminar rib graft fusion, and more recently using either transarticular screw fixation in the older patient, or lateral mass screws at C-1 and rod fixation with either C-2 pars interarticular screw fixation or pedicle screw fixation. A C-2 translaminar screw fixation is also described. Occipitocervical fusions are performed with rib grafts in patients younger than 6 years of age. Subsequently, above that age, contoured loop fixation was performed, and in the past 8–10 years, screw and rod fixation was used. Abnormal spine growth was not observed in children who underwent craniocervical stabilization below the age of 5 years (clearly the bone grew with the patient). However, no deleterious effects were noted in the children treated with rigid instrumentation. The success rate for bone fusion alone was 98%. The author's success rate with rigid instrumentation is nearly 100%. A detailed review of the technique of fusion is presented, as well as the indications and means of avoidance of complications, their prevention, and management.

Full access

Arnold H. Menezes

Os odontoideum is an uncommon craniovertebral junction (CVJ) abnormality that exists as a separate ossicle apart from a hypoplastic dens. It usually moves with the clivus or the anterior arch of C-1 (dystopic) or rarely with the dens (orthotopic). Its genesis and natural history have been debated, and its proper treatment remains uncertain.

Two hundred and sixty patients, with symptomatic os odontoideum, were evaluated by the author over a 20-year period; the author performed surgery in 134 of these patients. In a prospective study the author evaluated the early childhood history of trauma, the dynamic studies of motion, and the effects of traction by using pleuridirectional tomography, computerized tomography (CT), CT myelography and magnetic resonance (MR) imaging. Operative findings were documented.

Early childhood trauma to the CVJ was recorded in 74 patients, in 30 of whom normal odontoid processes were documented at initial examination prior to the patient reaching age 4 years.

Acute neurological deterioration following trauma occurred in 63 of 134 patients. Symptoms were insidious in 71 of 134 patients. In six patients, who presented with acute neurological deterioration after trauma and in whom an abnormal spinal cord signal in the cervicomedullary junction was demonstrated on MR imaging, normal CVJ motion dynamics were shown. Motion dynamics varied and were unique to each patient. Irreducible ventral CVJ disease causing cervicomedullary compromise occurred in 28 patients in whom a transpharyngeal ventral decompressive procedure was necessitated. During the transoral operation, the transverse portion of the cruciate ligament was found to be located anterior to the axis body. All patients required dorsal CVJ arthrodesis, which, in 46, was limited to the C1-2 segment. Instability at the C1-2 joints was always multidirectional, as demonstrated on preoperative neuroimaging studies as well as at operation.

Sixteen patients presented after completed primary C1-2 dorsal fusion and with worsening deficits. They improved when the range of the fusion was extended to the occiput or if the ventrally located lesion was excised.

Os odontoideum is associated with early childhood trauma and is an acquired phenomenon. The presence of abnormal motion dynamics necessitates surgical intervention as do associated neurological deficits. Asymptomatic patients in whom os odontoideum is incidentally discovered and in whom no abnormal motion dynamics are demonstrated should be followed closely.

Restricted access

Evaluation and treatment of congenital and developmental anomalies of the cervical spine

Invited submission from the Joint Section Meeting on Disorders of the Spine and Peripheral Nerves, March 2004

Arnold H. Menezes

✓ Congenital and developmental osseous abnormalities of the cervical spine can result in neural compression ranging from the medulla oblongata to the cervicothoracic spinal cord junction. These may present in infancy as scoliosis and even limb weakness. A high index of suspicion is essential. Neurodiagnostic imaging relies on high-resolution computerized tomography (CT) scanning and three-dimensional CT reconstructions as well as magnetic resonance imaging and angiography. The anatomical/physiological CT factors considered when developing a surgical approach are: 1) the stability and reducibility of the lesions; 2) direction and manner of encroachment of the lesion on the neural structures; 3) neural and vascular abnormalities; and 4) growth potential of the affected area. Primary stabilization is required for reducible lesions, whereas irreducible lesions are decompressed in the manner in which encroachment has occurred. Instability, whether present before or after operative intervention, required spinal stabilization. Illustrative examples of this approach are presented.

Restricted access

Brian J. Dlouhy and Arnold H. Menezes

Osteopetrosis is a heterogeneous group of rare, inherited disorders of the skeleton that results in neurological manifestations due to restriction of growth of cranial foramina and calvarial thickening. A 25-year-old woman with a history of autosomal dominant osteopetrosis presented to the authors' institution with headache worsened by exertion and radiating from the occipital region forward with episodes of choking/coughing when eating and a loss of gag reflex on physical examination. On MR imaging, she was found to have severe posterior fossa calvarial thickening resulting in a small posterior fossa and tonsillar ectopia of 9 mm and compression and deformation of the brainstem. She underwent posterior fossa craniectomy, foramen magnum decompression, and partial C-1 laminectomy with external durotomy. The patient did well postoperatively with resolution of symptoms. This case describes a new neurological manifestation of autosomal dominant osteopetrosis. To the authors' knowledge, this report represents the first described case of extreme posterior fossa calvarial thickening from autosomal dominant osteopetrosis with associated Chiari I malformation (CM-I) requiring posterior fossa decompression and extradural decompression. Given previously published MR imaging data that demonstrate the association of osteopetrosis and CM may be more common than in this case alone, the authors discuss the need for further investigation of the incidence of CM-I in patients with autosomal dominant osteopetrosis. Additionally, they review osteopetrosis and other diagnoses of calvarial hyperostosis presenting as CM-I.

Restricted access

Nader S. Dahdaleh and Arnold H. Menezes

The combination of unilateral trigeminal and vagal nerve dysfunction is a rare presentation in patients with Chiari malformation Type I (CM-I). The authors present a case of incomplete lateral medullary syndrome in a patient with CM-I. The patient's symptoms of decreased unilateral facial sensitivity to pain and temperature and her vocal cord dysfunction reversed after posterior fossa decompression and intradural exploration. Although rare, clinicians should be aware of this presentation as part of a protean spectrum of symptoms in patients with CM-I.

Restricted access

Gregory W. Albert and Arnold H. Menezes

Object

The objective of this study was to describe a single surgeon's experience managing craniovertebral junction (CVJ) disease due to ankylosing spondylitis.

Methods

The authors undertook a retrospective review of the records of patients with CVJ disease due to ankylosing spondylitis who were evaluated and treated by the senior author. Charts were reviewed for symptoms and signs at presentation, radiography results, treatment, and outcome. In addition, some of the patients had pathology reports available for review.

Results

Eight patients with CVJ disease due to ankylosing spondylitis were identified who were evaluated by the senior author in the years 1990–2008. The most common presenting symptoms were neck pain (37.5%), cranial neuropathy (37.5%), and sensory disturbance (62.5%). On examination, the most common findings were limited cervical range of motion (37.5%), weakness (50%), and myelopathy (75%). Radiographic evaluation revealed atlantoaxial subluxation, retroodontoid pannus formation, basilar invagination, and bone erosion. Surgery was offered to all of the patients, 7 of whom underwent operations. In most cases, the treatment was transoral–transpalatopharyngeal decompression followed by occipitocervical fusion. One patient with a reducible lesion underwent dorsal fusion alone. Neurological outcomes were favorable overall.

Conclusions

The incidence of CVJ disease in patients with ankylosing spondylitis varies among reports. These cases are rare in most neurosurgery clinics. It is important to recognize that patients with ankylosing spondylitis are at risk for CVJ disease, similar to patients with rheumatoid arthritis. Principles common to the management of other CVJ pathologies apply to these patients as well.

Full access

Raheel Ahmed and Arnold H. Menezes

Clinical presentation of craniovertebral junction disorders may range from acute catastrophic neurological deficits to insidious signs and symptoms that may mask the underlying etiology. Prompt recognition and treatment is essential to avert long-term neurological morbidity. Proatlas segmentation disorders are a rare group of developmental disorders involving the craniocervical junction. Abnormal bony segmentation leads to malformed bony structures that can in turn lead to neurological deficits through bony compression of the cervicomedullary junction. This report details a proatlas segmentation defect presenting as palatal myoclonus, a rare movement disorder. The clinical presentation, surgical management, and neuroanatomical basis for the disorder is presented. This report highlights the myriad clinical presentations of craniovertebral disorders and emphasizes a rare but treatable etiology for palatal myoclonus.

Restricted access

Timothy C. Ryken and Arnold H. Menezes

✓ Six patients with achondroplasia and symptoms suggestive of cervicomedullary junction compression are reviewed; these included three females and three males, with an average age of 8 years (range 7 months to 30 years). The mean duration of symptoms prior to intervention was 1.9 years. Symptoms included occipitocervical pain, ataxia, incontinence, apnea, and respiratory arrest. Radiological investigations consisted of plain films with flexion and extension views, pluridirectional tomography, thin-section computerized tomography, and magnetic resonance imaging. Typical findings included marked foramen magnum stenosis, ventrolateral cervicomedullary junction compression secondary to central and paramesial basilar invagination, and dorsal cervicomedullary junction compression secondary to ligamentous hypertrophy and invagination of the posterior atlantal arch. All patients underwent posterior fossa decompression and atlantal laminectomy. Surgery consistently revealed marked dorsal and paramesial overgrowth of the rim of the foramen magnum, with thickening and invagination of the atlantal posterior arch and a dense fibrotic epidural band resulting in dorsal cervicomedullary compression. Intraoperative ultrasonography was used to determine the extent of decompression required.

Three patients required duraplasty. Three patients had concurrent hydrocephalus, two of whom had undergone ventriculoperitoneal shunting prior to surgical decompression of the posterior fossa. One patient developed a pseudomeningocele postoperatively, requiring serial lumbar punctures before it resolved. No patient developed craniovertebral instability following decompression. Improvement or resolution of symptoms was noted in all patients, with an average follow-up period of 4.8 years. Thus, cervicomedullary compression in patients with achondroplasia can be successfully treated with dorsal decompression of the craniovertebral junction. Dense epidural fibrotic bands are frequently noted in these cases and must be aggressively released to ensure satisfactory decompression.

Restricted access

Arnold H. Menezes and John C. VanGilder

✓ The anterior transoral-transpharyngeal operation to correct ventral irreducible compression of the cervicomedullary junction was utilized in 72 individuals. The patients' ages ranged from 6 to 82 years, and 29 were children. The pathology encountered was primary basilar invagination, rheumatoid irreducible cranial settling, secondary basilar invagination due to migration of odontoid fracture fragments, dystopic os odontoideum, granulation masses, clivus chordoma, osteoblastoma, and chondroma of the atlas. Fifteen patients had associated Chiari malformation with basilar invagination. Fifty-two patients required subsequent atlantoaxial or occipitocervical fusion. Neurological improvement was the rule. There were two deaths within 30 days of surgery: one from myocardial infarction 4 weeks after surgery and one from Gram-negative septicemia of urinary tract origin. There was one pharyngeal wound infection. The ventral transoral approach provides a safe, rapid, and effective means for decompression of the abnormal craniovertebral junction.