Case Illustration 1

Arachnoid Cyst and Basilar Invagination

An 18-year-old male patient had torticollis ( Fig. 49.1 ). There was no neurological deficit.

Investigations showed basilar invagination and severe torticollis. An arachnoid cyst was seen on the side contra-lateral to the torticollis. The patient is under neurological observation.

Case Illustration 2

Bifid Anterior and Posterior Arches of the Atlas Associated with Mobile Reducible Atlantoaxial Dislocation

An 8-year-old girl presented with torticollis since birth, frequent falls, and progressive spastic quadriparesis ( Fig. 49.2 ). Investigations showed mobile and reducible atlantoaxial dislocation. The cord was severely compressed. The anterior and posterior arches of the atlas were bifid. The patient underwent lateral mass plate and screw fixation. Following the surgery, she showed dramatic clinical recovery. The presence of bifid arches signifies a defect in the embryogenetic process. In presence of bifid posterior arch of atlas, midline wiring procedure may not have been possible.

Case Illustration 3

Bilateral Lateral Dislocation

A 12-year-old boy had trauma to the head due to a traf f ic accident ( Fig. 49.3 ). Apart from pain in the neck, there was no neurological deficit. The patient was treated conservatively. At 1-year follow-up, he was asymptomatic. However, the investigations showed persistent dislocation of the facets and fractures in the atlas and its ring. Lateral mass fixation procedure is possible in such a situation when midline wiring techniques may not be possible and may be technically more difficult and dangerous.

Case Illustration 4

C2 Tuberculosis Radiologically Simulating a Chordoma

A 78-year-old woman who was diagnosed with breast cancer 8 years ago had progressive weakness of all four limbs and respiratory distress for about 1 month. Investigations revealed a lesion that destroyed a large part of the anterior elements of the C2 vertebra ( Fig. 49.4 ). There was a prevertebral and retrovertebral soft tissue lesion. Initially, the lesion was believed to be a metastasis. The patient underwent anterior and posterior evacuation of purulent material and destroyed bone tissue. Histopathology revealed that the lesion was tuberculous in nature. The patient was subsequently treated with antituberculous drugs. She has shown progressive neurological recovery following this treatment. At a follow-up after 6 months, investigations showed resolution of the lesion.

Case Illustration 5

Chordoma Involving C2 Vertebra

Chordomas frequently involve the C2 vertebra and present a complex therapeutic challenge. A 60-year-old man presented with tingling, numbness in both upper limbs, and weakness of all four limbs. Examination revealed spastic quadriparesis. Investigations showed a lesion at the level of the C2 vertebra. It was isointense on T1-weighted images and hyperintense on T2-weighted images ( Fig. 49.5 ). The lesion caused destruction of the vertebral body, the facet of the axis, and the odontoid process. The patient underwent transoral surgery with radical but incomplete resection of the tumor. Histopathology of the lesion revealed that it was a chordoma. Chordomas in this location are common. High recurrence rates and the relentlessly progressive course of the disease are hallmarks of chordoma in this region.

Case Illustration 6

Chordoma Involving C2 Vertebra

Chordomas frequently involve the C2 vertebra and present a complex therapeutic challenge. A 35-year-old man had surgery for a large clival chordoma ( Fig. 49.6 ). Transcervical partial resection of the tumor and posterior occipitocervical fixation were done at that time. Eight months after surgery, the patient was referred to us in a poor neurological state. He had severe spastic grade 1 quadriparesis and needed ventilatory assistance for breathing. The tumor was massive and extended on both sides of the anteriorly displaced ororespiratory passages. The patient was reoperated. The anterior cervical approach was reopened, and the tumor was radically resected from the left side. The involved vertebral bone was removed, and the tumor extending to the right side was resected partially from underneath the esophagus and trachea. The soft nature of the tumor assisted in resection, and the planes of soft tissue made by tumor expansion assisted in radical tumor resection. Following the radical surgery on one side, and while waiting for surgery on the contralateral side, the patient showed dramatic clinical recovery. When seen after 1 month, he could walk unaided. He never returned for second-stage surgery for the tumor on the right side of the trachea.

Case Illustration 7

Circumferential Cord Tuberculous Granulations1

A 49-year-old woman presented with a 7-month history of progressive quadriparesis. At the time of admission, she had spastic grade 4 quadriparesis. Both T1- and T2-weighted images revealed a hypointense lesion surrounding the upper cervical cord ( Fig. 49.7 ). Computed tomography (CT) scan showed the mass to be hyperdense and contrast enhancing in nature. During surgery, a thick film of extradural granulation tissue was encountered that was partially removed. Histology revealed that the lesion was chronic granulation tissue. The patient was placed on empirical antituberculous drugs. She progressively recovered on drug treatment and when seen after 3 years was symptom free. Repeat investigations showed resolution of the granuloma.

Case Illustration 8

Clival Dysgenesis Associated with Chiari Malformation and Syringomyelia2

An 11-year-old boy presented with the complaints of neck pain and difficulty in walking. He had nasality of voice since birth. Over a period of time, he had noticed that he was unable to run as fast as his friends and of late had a tendency to fall on uneven ground. On examination, he had a short neck and an abnormal shape of the occipital bone. He also had scoliosis of the dorsal spine with a convexity to the right. He had spasticity in all four limbs with hyperreflexia, but the power was grade 5 in all muscle groups. Sensory examination was normal. He had no bowel or bladder complaints. He was able to ambulate on his own. CT scan showed a rudimentary clivus with failure of fusion between the sphenoidal and occipital parts of the clivus and a shortened bone representing the clivus capping the dens. There was also evidence of C2–C3 fusion. There was basilar invagination, with the odontoid being 2.28 cm above the Chamberlain line. The atlantodental interval was normal, and there was no evidence of atlantoaxial instability. Magnetic resonance imaging (MRI) of the craniovertebral junction and cervical spine showed tonsillar herniation, as well as holocord syringomyelia with septations ( Fig. 49.8 ). Dynamic flexion-extension images of the cervical spine did not show any instability. The patient was treated with foramen magnum decompression. Postoperatively, the patient improved in spasticity in all limbs and also noticed improvement in neck pain.

Case Illustration 9

Craniofrontonasal Dysplasia Associated with Chiari Malformation7

A 46-year-old woman had swelling at the root of the nose since birth. She had a history of continuous, dull aching pain in the nape of the neck and left upper extremity for ∼8 years. There was slowly progressive weakness and numbness of the left upper limb over that period. For 1 year, she had facial asymmetry and bilateral hearing impairment. For a period of ∼3 months, she had progressive quadriparesis, the left side being weaker than the right. When admitted, she needed support to walk and preferred wheelchair ambulation.

On neurological examination, she had right lower motor neuron facial paresis and bilateral partial sensorineural hearing loss. There was hypotonia in the left upper limb and spasticity in the legs. No clear muscle wasting was seen. There was grade 4 hemiparesis on the left side. Also noticed was a dissociated cervicodorsal sensory loss in the left upper limb and left half of the trunk between C3 and T12 dermatomes. The joint position sense was impaired in all limbs. Romberg sign was positive. The patient had a broad-based gait and required bilateral support to walk. She had a characteristic facies with frontal bossing, prominent supraorbital ridges, broad nasal root, bilateral epicanthic folds, hypertelorism, hypoplastic maxillae, and small ear lobules ( Fig. 49.9 ). She also had bilateral pseudophakia due to previous cataract surgery, retrognathia, and multiple hamartomas in the floor of the mouth. The swelling at the root of the nose was nontender, hard, and irreducible. Her neck showed pseudowebbing due to long clavicles. She also had pectus carinatum, scoliosis of the thoracic spine with convexity to the right, simian crease in the left hand, and cutaneous syndactyly of the right hand. Audiogram demonstrated bilateral mild sensorineural hearing loss.

The patient had two daughters, ages 23 ( Figs. 49.10 and 49.11 ) and 21 years ( Figs. 49.9 and 49.12 ), who had similar swellings at the root of the nose since birth. On examination, both daughters had prominent supraorbital ridges, broad nasal root, bilateral epicanthal folds, hypertelorism, hypoplastic maxillae, small ear lobules, pectus carinatum, and hamartomas in the floor of the mouth ( Fig. 49.9 ). In addition, the elder daughter had thoracic scoliosis and a simian crease in the right hand, and her right scapula was higher than the left. Both daughters did not have any neurological symptom or deficit. The patient’s parents, grandparents, other siblings, and husband were normal.

Neuroradiological examination was performed of the entire family. The affected patient and her daughters had similar findings on CT scan of the cranium and face, which showed diff use hyperostosis and sclerotic thickening of the calvaria and skull base, including both petrous bones and nasal and lacrimal bones, with hypoplasia of the maxillae and mandibles ( Figs. 49.10, 49.11, and 49.12 ). MRI of the patient and elder daughter revealed Chiari I malformation and cervicodorsal syringomyelia ( Figs. 49.10c and 49.11b, c ). The younger daughter did not have Chiari malformation ( Fig. 49.12b ). A skeletal survey was performed on all three women, which did not reveal any other abnormality. A genetic study documenting the mutated gene was not performed.

The patient underwent suboccipital, foramen magnum, and posterior arch of the atlas decompression. The bone was markedly thick and hard and moderately hypervascular. Postoperative recovery was uneventful. On 13-month follow-up, the patient reported significant improvement in the numbness of the left-sided limbs and relief of her neck pain. She was able to walk unaided. In the period of observation, the two daughters of the patient had developed no neurological symptom.

The term craniofrontonasal dysplasia was first introduced by Cohen in 1979 to describe a patient with coronal craniosynostosis, hypertelorism, limitation of shoulder movements, and digital abnormalities.8 It has also been referred to as craniofrontonasal syndrome. The typical manifestations of this syndrome in female patients are severe hypertelorism (frequently asymmetrical) with a central nasal groove, frontonasal dysplasia, and unilateral or bilateral coronal craniosynostosis (brachycephaly or plagiocephaly). The three female family members described in our case report had the above-mentioned characteristics and could be labeled as having this syndrome phenotypically. Male patients are usually affected mildly with hypertelorism only.

Our cases suggest that diff use hyperostosis and sclerotic thickening of the skull base produce overcrowding of posterior fossa structures and promote hindbrain herniation through the foramen magnum. Early recognition of the syndrome is important for genetic counseling, as well as for detection of Chiari malformation and syringomyelia in an asymptomatic stage. This will permit close neurological monitoring and appropriate surgical intervention at an incipient stage.

Case Illustration 10

Endodermal Cysts

Endodermal cysts are rare intracranial tumors, and only isolated cases are reported in the literature. Endodermal cysts are known by a variety of names, such as epithelial, enterogenous, neurenteric, bronchogenic, foregut, and respiratory cysts. Some studies suggest that colloid cyst, Rathke cleft, and enterogenous cyst all represent endodermal inclusion cysts, have a common histogenesis, and are named differently according to their respective location. Similar cysts are more frequently found in the lower cervical and upper dorsal spine and are lined by the presumed endodermal-derived epithelium. They most commonly occur in the posterior cranial fossa, and most of them have been located anterior or anterolateral to the brainstem. Frequently, they extend anterior to the cord at the craniocervical junction. Tumors can be diagnosed on the basis of their characteristic radiological features. The image intensities on MRI are dependent on the viscosity of the cyst fluid. The cysts are large, iso- to hyperintense on T1-weighted images, and iso- to hypointense on T2-weighted images ( Fig. 49.13 ). Usually there are associated small soft calcifications in proximity to the major arteries. During surgery, the cyst material usually has a puslike hue and consistency. The wall of the cyst is usually thin and “arachnoid-like.” In 2005,9 we proposed that evacuation of the cyst contents and safe partial resection of the cyst wall is sufficient for long-term control of these benign lesions. The cyst contents should be radically removed, and spillage into the subarachnoid space should be avoided, as such an intraoperative event can result in “chemical” meningitis.10