Injuries involving the transverse atlantal ligament: classification and treatment guidelines based upon experience with 39 injuries

Comprehensive anatomic and clinical analyses of 39 patients with injuries involving the transverse atlantal ligament or its osseous insertions were performed to assess the morphology of the injured ligaments and the patients' capacity to heal. Injuries of the upper cervical spine were screened with plain radiographs, thin-section computed tomography, and magnetic resonance imaging studies. The injuries were classified as disruptions of the substance of the ligament (Type I injuries, n = 16) or as fractures and avulsions involving the tubercle for insertion of the transverse ligament on the C1 lateral mass (Type II injuries, n = 23). These two types of injuries had distinctly different clinical characteristics that were useful for determining treatment. Type I injuries were incapable of healing satisfactorily without internal fixation; they should be treated with early surgery. Type II injuries, which rendered the transverse ligament physiologically incompetent even though the ligament substance was not torn, should be treated initially with a rigid cervical orthosis, because they had a 74% success rate nonoperatively. Surgery should be reserved for patients with Type II injuries that have nonunion with persistent instability after 3 to 4 months of immobilization. Type II injuries had a 26% rate of failure of immobilization; therefore, close monitoring is needed to detect patients who will require delayed operative intervention.

Sudden death in rheumatoid arthritis with atlanto-axial dislocation

A post mortem material of 11 consecutive cases of severe atlanto-axial dislocation (a.a.d.) with cord compression is reported. The total number of deaths from rheumatoid arthritis (RA) during the period of 5 years was 104, and all were autopsied. Neurological symptoms correlated poorly to fatal a.a.d. Hemiplegia was found in three cases, one of which, however, was caused by thrombosis cerebri. Spastic signs were transiently recorded in two patients and dysphagia in a further two. Five patients had a history of recent vomiting. A.a.d. was the sole or main cause of death in 8 cases and contributory in 2. Sudden death occurred in 7 of the cases. Only 2 cases had obtained a correct diagnosis intra vitam. The CNS findings at autopsy consisted of cord compression (11/11 cases), cord malacia (2/11) and cerebral oedema (3/11). One case had polyarteritis and renal amyloidosis and one pulmonary carcinoma with metastatic spread. Signs of active inflammation in the axial joints were present in 4 cases. This study, based on systematic post mortem examinations, revealed an unexpectedly high and not previously reported incidence of fatal medulla compression in RA patients with a.a.d. (10%).

MRI assessment of the alar ligaments in the late stage of whiplash injury--a study of structural abnormalities and observer agreement

Our aim was to characterise and classify structural changes in the alar ligaments in the late stage of whiplash injuries by use of a new MRI protocol, and to evaluate the reliability and the validity of this classification. We studied 92 whiplash-injured and 30 uninjured individuals who underwent proton density-weighted MRI of the craniovertebral junction in three orthogonal planes. Changes in the alar ligaments (grades 0-3) based on the ratio between the high signal area and the total cross-sectional area were rated twice at a 4-month interval, independently by three radiologists. Inter- and intraobserver statistics were calculated by ordinary and weighted kappa. Cases classified differently were reviewed to identify potential causes for disagreement. The alar ligaments were satisfactorily demonstrated in all cases (244 ligaments in 122 individuals). The lesions, 2-9 years after the injury, varied from small high-signal spots to high signal throughout the cross-sectional area. Signal was highest near the condylar insertion in 82 of 94 ligaments, indicating a lesion near that insertion, and near the dental insertion in eight, indicating a medial lesion. No grade 2 or 3 lesion was found in the control group. At least two observers assigned the same grade to 214 ligaments (87.7%) on the second occasion. In 30 ligaments (12.3%) this agreement was not obtained. Pair-wise interobserver agreement (weighted kappa) was fair to moderate (0.31-0.54) in the first grading, improving to moderate (0.49-0.57) in the second. Intraobserver agreement (weighted kappa) was moderate to good (0.43-0.70). Whiplash trauma can cause permanent damage to the alar ligaments, which can be shown by high-resolution proton density-weighted MRI. Reliability of classification of alar ligament lesions needs to be improved.

Modification of C1-C2 transarticular screw fixation by image-guided surgery

STUDY DESIGN

This is a feasibility study of image-guided surgery for C1-C2 transarticular screw fixation comparing postoperative screw position in a nonrandomized prospective cohort with a historic control group in which fluoroscopic guidance was used alone.

OBJECTIVES

To evaluate the potential benefits and disadvantages of image-guided surgery for C1-C2 screw placement.

SUMMARY OF BACKGROUND DATA

C1-C2 transarticular screw fixation is biomechanically superior to other current surgical stabilization procedures. The original technique for C1-C2 screw placement relies on anatomic landmarks and intraoperative fluoroscopy. Screw misplacement or anatomic variations can result in vertebral artery injury. Image-guided surgery involves using computed tomography (CT) data to plan the optimal screw trajectory before surgery and then use this data to guide screw placement during the actual surgery. Promising results of this technique are reported in the literature, but no direct comparison between image-guided surgery and conventional surgical techniques has been previously reported.

METHODS

The image-guided surgery group consisted of 37 prospective patients. The historic control group included 78 patients who had similar surgeries performed using only fluoroscopic guidance. For the image-guided surgery group, subluxation was reduced by positioning at the time of CT examination. The CT data were transferred to a StealthStation (Sofamor-Danek, Memphis, TN) surgical planning and guidance computer system, and an optimal screw trajectory was determined for the right and left transarticular screws. After matching the surgical field to the virtual computer field, C2 was drilled according to the planned screw trajectory, and screws were placed. Plain radiographs and CT were used for postoperative evaluation of the image-guided surgery group.

RESULTS

Image-guided surgery reduced but did not eliminate the risk of screw misplacement. Surgical time was not increased overall.

CONCLUSIONS

Image-guided surgery is an effective tool for the achievement of correct screw placement in C1-C2 transarticular screw fixation procedures. The procedure remains technically demanding.

An anatomical basis for the neck-tongue syndrome

The C2 nerve roots and rami were dissected in five cadavers to explore the pathogenesis of Neck-Tongue Syndrome. The most likely cause of the simultaneous occurrence of suboccipital pain and ipsilateral numbness of the tongue is an abnormal subluxation of one lateral atlanto-axial joint with impaction of the C2 ventral ramus against the subluxated articular processes.

Cervical myelopathy caused by hypoplasia of the atlas: two case reports and review of the literature

OBJECTIVE AND IMPORTANCE

Congenital anomalies of the posterior arch of the atlas (C1) are uncommon. They range from partial clefts to total agenesis of the posterior arch. Developmental cervical canal stenosis is a congenital anomaly that may cause cervical myelopathy. Myelopathy caused by cervical stenosis at the level of the atlas has been reported in only three cases. We present two cases of nontraumatic cervical myelopathy caused by spinal stenosis at the level of the atlas associated with a hypoplastic but complete posterior arch of C1.

CLINICAL PRESENTATION

Two elderly Chinese men developed cervical myelopathy gradually during months to years, without preceding trauma. Imaging revealed a hypoplastic but complete posterior C1 arch associated with changes of spondylosis in both patients, producing severe spinal stenosis and spinal cord compression. Posterior decompression was achieved in both by the removal of the posterior arch of C1 with its surrounding thickened posterior ligaments. Symptoms and clinical findings improved in the two patients during the follow-up period.

CONCLUSION

The anomaly presented in our two cases differs from the established classification of congenital abnormalities of the posterior arch of the atlas, suggesting a different embryological defect. The hypoplastic posterior C1 arch created a congenitally narrowed spinal canal in our patients, rendering the spinal cord more susceptible to compression related to degenerative changes of the spine. Surgical removal of the shortened posterior C1 arch and surrounding degenerative ligaments is an effective treatment for symptomatic patients with this condition.

Aneurysmal bone cyst of the first cervical vertebrae in a child treated with percutaneous intralesional injection of calcitonin and methylprednisolone. A case report

STUDY DESIGN

First published report of a child with an aneurysmal bone cyst (ABC) of the first cervical vertebrae treated successfully with intralesional injection of calcitonin and methylprednisolone.

OBJECTIVES

To describe a safe and effective nonsurgical treatment method for an ABC of the first cervical vertebrae.

SUMMARY OF BACKGROUND DATA

Aneurysmal bone cysts of the spine comprise from 3% to 20% of all such lesions. Upper cervical spine involvement is rare and these lesions are difficult to treat. Standard treatment with curettage and bone grafting or other alternatives such as radiation therapy or embolization may not be possible in this location. Percutaneous injection with a variety of agents has also been described. Methylprednisolone and calcitonin were selected in this case in an effort to combine the proposed angiostatic and fibroblastic inhibitory effects of steroid with the proposed osteoclastic inhibitory and promotion of new bony trabeculae formation effects of calcitonin.

METHOD

This case was described, and pertinent literature reviewed.

RESULTS

Sclerosis and shrinkage of the lesion with concomitant symptom resolution occurred after two injections with calcitonin and methylprednisolone via computed tomography (CT) guidance. No complications occurred. The lesion remained quiescent at a 2-year 7-month follow-up.

CONCLUSIONS

Percutaneous intralesional injection of an ABC of the first cervical vertebrae with calcitonin and methylprednisolone in a child via CT guidance was a safe and effective treatment. This is a promising treatment for surgically inaccessible aneurysmal bone cysts.

Transoral decompression, anterior plate fixation, and posterior wire fusion for irreducible atlantoaxial kyphosis in rheumatoid arthritis

STUDY DESIGN

Fifteen consecutive patients with irreducible atlantoaxial kyphosis caused by rheumatoid arthritis were treated by combined transoral odontoid resection, anterior plate fixation, and posterior wire fusion.

OBJECTIVES

To investigate the clinical results of this new surgical procedure.

SUMMARY AND BACKGROUND DATA

Irreducible atlantoaxial kyphosis in rheumatoid arthritis results from a destruction of the craniocervical joint ligaments and the anterior aspects of the lateral atlantoaxial joints. The development of a paradental synovial pannus and atlantoaxial joint impaction prevents reduction by conservative treatment, such as skull traction. Posterior surgical procedures for the treatment of the irreducible atlantoaxial kyphosis with spinal cord compression have been associated with high morbidity and mortality.

METHODS

Fifteen consecutive patients were treated by transoral odontoid resection. The fixation was performed with anterior plating, according to the method of Harms in combination with posterior wire fusion according to Brooks. Before and after surgery, evaluation was performed using the parameters of pain (visual analog scale), range of motion, and subjective assessment of improvement and the Health Assessment Questionnaire. The neurologic deficit was defined according to the classifications proposed by Ranawat, Frankel, and Nurwick. Plain radiographs, including lateral flexion and extension views, and magnetic resonance scans were obtained.

RESULTS

No perioperative fatality occurred. The average clinical and radiographic follow-up was 50.7 +/- 15.6 months (range, 26-77). Postoperative pain was relieved (mean pain score before surgery, 7.9 +/- 1.87; after surgery, 3.8 +/- 1.27), and the range of motion of all patients increased (mean 21.5 +/- 14.0 degrees for rotation; mean 17.2 +/- 5. 54 degrees for bending). The score on the Health Assessment Questionnaire increased in three patients, remained unchanged in three and decreased in six patients (three had died). All patients improved at least one Ranawat level after surgery, except a patient in Ranawat Class II, whose condition remained unchanged. All patients were satisfied with the procedure and reported subjective improvement.

CONCLUSION

Transoral plate fixation combined with posterior wire fixation after transoral odontoid resectionis an effective, reliable, and safe procedure for the treatment of irreducible atlantoaxial kyphosis in rheumatoid arthritis.

Comparison of atlas- and magnetic resonance imaging-based stereotactic targeting of the globus pallidus internus in the performance of deep brain stimulation for treatment of dystonia

OBJECT

To assess the validity of relying on atlases during stereotactic neurosurgery, the authors compared target coordinates in the globus pallidus internus (GPi) obtained using magnetic resonance (MR) imaging with those determined using an atlas. The targets were used in deep brain stimulation (DBS) for the treatment of generalized dystonia.

METHODS

Thirty-five patients, who were treated using bilateral DBS of the GPi, were included in this study. The target was selected on three-dimensional MR images by direct visual recognition of the GPi. The coordinates were automatically recorded using dedicated software. They were translated into the anterior commissure-posterior commissure (AC-PC) coordinate system by using a matrix transformation process. The same GPi target was defined, based on the locations of brain structures shown in the atlases of Schaltenbrand and Talairach. Magnetic resonance imaging-based GPi target coordinates were statistically compared with the corresponding atlas-based coordinates by applying the Student t-test. A significant difference (p < 0.001) was demonstrated in x, y, and z directions between MR imaging-based and Schaltenbrand atlas-derived target coordinates. The comparison with normalized Talairach atlas coordinates demonstrated a significant difference (p < 0.01) in the y and z directions, although not in the x direction (p = 0.12). No significant correlation existed between MR imaging-based target coordinates and patient age (p > 0.1). No significant correlation was observed between MR imaging-based target coordinates and patient sex in the y and z directions (p > 0.9), although it was significant in the x direction (p < 0.05). A significant variation in coordinates and the length of the AC-PC line was revealed only in the y direction (p < 0.005).

CONCLUSIONS

A significant difference was found between target coordinates obtained by direct visual targeting on MR images (validated by postoperative clinical results) and those obtained by indirect targeting based on atlases.

CADAVERIC MORPHOMETRIC ANALYSIS FOR ATLANTAL LATERAL MASS SCREW PLACEMENT

OBJECTIVE

Atlantal lateral mass screws provide an alternative to C1/C2 transarticular screws and, in some cases, can obviate the need for extending a fusion to the occiput. For these reasons, C1 lateral mass screws are becoming increasingly popular. However, the critical local anatomy and unfamiliarity with this new technique can make C1 screw placement more challenging.

METHODS

Morphometric analysis was performed on 74 cadaveric spines obtained from the Department of Anatomy at the Keck School of Medicine, University of Southern California. Critical measurements were determined for screw entry points, trajectories, and lengths for application of the technique described by Harms and Melcher.

RESULTS

The mean height and width for screw entry on the posterior surface of the lateral mass were 3.9 and 7.3 mm, respectively. The maximum medialized screw trajectory ranged from 25 to 45 degrees (mean, 33 degrees). The mean maximal screw length to obtain bicortical purchase was 22.5 mm, and the mean minimum screw depth was 14.4 mm. Screw depths varied on the basis of the entry point, trajectory, and vertebral morphology. The overhang of the posterior arch averaged 11.4 mm (range, 6.9-17 mm). All specimens could accommodate 3.5-mm lateral mass screws bilaterally with proper preparation of the entry site.

CONCLUSION

Significant variations in the morphology of C1 exist. However, the large size of the atlantal lateral mass makes screw placement forgiving. Preoperative computed tomographic scans and intraoperative fluoroscopy are useful in guiding proper screw placement. Close attention should be paid to preparation of the screw entry site.

Gross morphology of the bridges over the vertebral artery groove on the atlas

The bony bridges of the atlas over the "groove of the vertebral artery" are commonly seen in plain radiographs of the cervical spine, and it is a subject of controversy whether they cause compression of the underneath lying vertebral artery. To clarify this we examined a total of 176 dried and complete atlas vertebrae and found the presence of a "canal for the vertebral artery" (CVA) in 10.23% and an incomplete "canal for the vertebral artery" in 24.43%. The CVA and incomplete CVA is more common in males (11.11% and 24.9%) than in females (9.3% and 24.42%). We found a higher incidence of CVA in laborers (37.5%) than in nonlaborers (4.16%). The incomplete CVA appeared to be more characteristic in the age group of 5-44 years. In the age group of 45-90 years the CVA was characteristic, which probably means that an incomplete CVA is the precursor of a CVA. The superoinferior diameter of the CVA canal ranged from 5.1 to 6.1 mm at the right side and from 4.6 to 5.8 mm at the left side, while the anteroposterior diameter was 5.6-6.9 mm at the right side and 6.1-7.2 mm at the left side. We also found a high incidence of coexistence of CVA and the "retrotransverse foramen" (72.22%) which means that because of possible compression of the vertebral veins the blood flow is directed into the small vein of the retrotransverse foramen. Finally, in 93.5% of unilateral CVA a deeply excavated contralateral "groove of the vertebral artery" was found.

Anterolateral decompression of the atlantoaxial vertebral artery for symptomatic positional occlusion of the vertebral artery. Case report

A case of repeated vertebrobasilar ischemic attacks related to head rotation (bow hunter's stroke) is reported. With head rotation of 45 degrees or more to the right, the patient would become lightheaded and feel as if she were going to lose consciousness. Angiography performed when head rotation was to the right revealed mechanical compression of the left vertebral artery at the foramen transversarium of the axis and an occluded right vertebral artery. Untethering of the vertebral artery as it passed through the foramen transversarium of the atlas in this case completely relieved the patient's symptoms. The authors conclude that contralateral vertebral artery occlusion predisposed this patient to symptomatic vertebrobasilar insufficiency secondary to ipsilateral vertebral artery mechanical stenosis induced by head turning.

Pathology of the cervical spine in rheumatoid arthritis: a controlled study of 44 spines

Cervical spines (with occiputs) of 44 patients with rheumatoid arthritis (RA) were compared with 44 control spines from patients without RA, matched for sex and age. There were six severe and seven slight atlanto-axial dislocations (both horizontal and vertical, two of which had been treated surgically) in the RA group and none in the control group. Ankylosis, synchondrosis, syndesmosis, bone erosions, and redness of synovial tissue in the atlanto-axial, atlanto-occipital and cervical intervertebral joints were more frequent in the RA group than in the control spines. The lesions permitting the best discrimination between the RA and control groups were used to calculate an overall score for the whole cervical spine. Sixteen of the 44 RA patients scored higher than the highest control value; only nine scored lower than the median control score. A higher score than the average value found for the RA spines was obtained by the male patients, the patients with seropositivity or subcutaneous nodules, the patients treated with corticosteroids, the patients who died in the Department of Rheumatology, and those whose death was related to the RA itself or to the treatment given.

Synovial cyst of the transverse ligament of the atlas in a patient with os odontoideum and atlantoaxial instability

STUDY DESIGN

A case report and review of the literature.

OBJECTIVE

To describe the diagnosis and successful treatment of a synovial cyst arising from the transverse ligament in a patient with os odontoideum and atlantoaxial instability.

SUMMARY OF BACKGROUND DATA

Synovial cysts arising from the transverse ligament of the atlas are extremely rare. Development of a synovial cyst is thought to be attributable to degenerative changes of the C1-C2 facet joints or to microtrauma. Direct excision of the cyst is the only treatment cited in previous reports.

METHODS

A synovial cyst arising from the transverse ligament of the atlas in a 45-year-old man with os odontoideum and atlantoaxial instability was treated surgically with posterior atlantoaxial fusion alone. The magnetic resonance images, surgical treatment, and related literature are reviewed.

RESULTS

Preoperative magnetic resonance images of the cervical spine showed a large cystic mass located ventral to the cord arising at the level of the transverse ligament of the atlas: the mass was of low signal intensity on T1-weighted images, was of high signal intensity on T2-weighted images, and was enhanced marginally with gadolinium-DTPA on T1-weighted images. Spontaneous regression of the cyst was identified on the follow-up magnetic resonance images taken 3 months after C1-C2 posterior wiring and fusion.

CONCLUSIONS

A patient with a synovial cyst arising at the C1-C2 junction ventrally at the level of the transverse ligament showed spontaneous regression of the lesion after C1-C2 posterior wiring and fusion.

Cervical vertebral body fusions in patients with skeletal deep bite

Cervical column morphology was examined in 41 adult patients with a skeletal deep bite, 23 females aged 22-42 years (mean 27.9) and 18 males aged 21-44 years (mean 30.8) and compared with the cervical column morphology in an adult control group consisting of 21 subjects, 15 females, aged 23-40 years (mean 29.2 years) and six males aged 25-44 years (mean 32.8 years) with neutral occlusion and normal craniofacial morphology. None of the patients or control subjects had received orthodontic treatment. For each individual, a visual assessment of the cervical column and measurements of the cranial base angle, vertical craniofacial dimensions, and morphology of the mandible were performed on a profile radiograph. In the deep bite group, 41.5 per cent had fusion of the cervical vertebrae and 9.8 per cent posterior arch deficiency. The fusion always occurred between C2 and C3. No statistically significant gender differences were found in the occurrence of morphological characteristics of the cervical column (females 43.5 per cent, males 38.9 per cent). Morphological deviations of the cervical column occurred significantly more often in the deep bite group compared with the control group (P < 0.05). Logistic regression analysis showed that the vertical jaw relationship (P < 0.05), overbite (P < 0.001), and upper incisor inclination (P < 0.01) were significantly correlated with fusion of the cervical vertebrae (R(2) = 0.40).

Anatomic landmarks of the glossopharyngeal nerve: a microsurgical anatomic study

OBJECTIVE

Compared with other lower cranial nerves, the glossopharyngeal nerve (GPhN) is well hidden within the jugular foramen, at the infratemporal fossa, and in the deep layers of the neck. This study aims to disclose the course of the GPhN and point out landmarks to aid in its exposure.

METHODS

The GPhN was studied in 10 cadaveric heads (20 sides) injected with colored latex for microsurgical dissection. The specimens were dissected under the surgical microscope.

RESULTS

The GPhN can be divided into three portions: cisternal, jugular foramen, and extracranial. The rootlets of the GPhN emerge from the postolivary sulcus and course ventral to the flocculus and choroid plexus of the lateral recess of the fourth ventricle. The nerve then enters the jugular foramen through the uppermost porus (pars nervosa) and is separated from the vagus and accessory nerves by a fibrous crest. The cochlear aqueduct opens to the roof of this porus. On four sides in the cadaver specimens (20%), the GPhN traversed a separate bony canal within the jugular foramen; no separate canal was found in the other cadavers. In all specimens, the Jacobson's (tympanic) nerve emerged from the inferior ganglion of the GPhN, and the Arnold's (auricular branch of the vagus) nerve also consisted of branches from the GPhN. The GPhN exits from the jugular foramen posteromedial to the styloid process and the styloid muscles. The last four cranial nerves and the internal jugular vein pass through a narrow space between the transverse process of the atlas (C1) and the styloid process. The styloid muscles are a pyramid shape, the tip of which is formed by the attachment of the styloid muscles to the styloid process. The GPhN crosses to the anterior side of the stylopharyngeus muscle at the junction of the stylopharyngeus, middle constrictor, and hyoglossal muscles, which are at the base of the pyramid. The middle constrictor muscle forms a wall between the GPhN and the hypoglossal nerve in this region. Then, the GPhN gives off a lingual branch and deepens to innervate the pharyngeal mucosa.

CONCLUSION

Two landmarks help to identify the GPhN in the subarachnoid space: the choroid plexus of the lateral recess of the fourth ventricle and the dural entrance porus of the jugular foramen. The opening of the cochlear aqueduct, the mastoid canaliculus, and the inferior tympanic canaliculus are three landmarks of the GPhN within the jugular foramen. Finally, the base of the styloid process, the base of the styloid pyramid, and the transverse process of the atlas serve as three landmarks of the GPhN at the extracranial region in the infratemporal fossa.

Experimental study of atlas injuries. II. Relevance to clinical diagnosis and treatment

Atlas injuries were produced in vitro and evaluated by radiographic examinations and anatomic studies from a clinical viewpoint. Ten cadaveric human upper cervical spine specimens were subjected to a high-speed axial impact. Injuries to the atlas consisted of six bursting fractures, two ruptures of the transverse ligament, one four-part fracture without a prominent bursting, and one posterior arch fracture. The major soft tissue injury involved the transverse ligament. There were five bony avulsions and three midsubstance tears. In this study, computed tomographic examinations clearly demonstrated the sites of fracture and bony avulsions of the transverse ligament. The best diagnostic tool for function of the transverse ligament was determined to be the atlantodental interval on flexion radiographs. Axial traction force reduced a bursting fracture of the atlas ring. The in vitro atlas injury model gives useful information for clinical diagnosis and treatment.

Craniovertebral junction lesions: our experience with the transoral surgical approach

The aim of this study is to review our experience with the transoral surgical management of anterior craniovertebral junction (CVJ) lesions with particular attention to the decision making and to the indication for a consecutive stabilization. During 10 years (1998-2007), 52 consecutive patients presenting exclusively fixed anterior compression at the cervicomedullary junction underwent transoral surgery. Mean age was 55.85 years (range 17-75 years). Encountered lesions were: malformation (32 cases), rheumatoid arthritis (11 cases), tumor (5 cases) or trauma (4 cases). A total of 79% of patients presented with chronic/recurrent headache (cranial and/or high-cervical pain), 73% with varying degrees of quadrip aresis, and 29% with lower cranial nerve deficits. All of the patients but two, with posterior stabilization performed elsewhere, underwent synchronous anterior decompression and posterior occipitocervical fixation. Adjuncts to the transoral approach (Le Fort I with or without splitting of the palate), tailored to the local anatomy and to the extension of the lesions, were performed in seven cases. Follow-up ranged between 4 and 96 months. Of 35 patients with severe preoperative neurological deficits, 33 improved. The remaining 15 patients who presented with mild symptoms, healed throughout the follow-up. Perioperative mortality occurred in two cases and surgical morbidity in eight cases (dural laceration, cerebrospinal fluid leak with meningitis, malocclusion, oral wound dehiscence and occipital wound infection). Delayed instability occurred in one patient because of cranial settling of C2 vertebral body. A successful surgery achieving a stable decompression at the CVJ is an expertise demanding procedure. It requires accurate preoperative evaluation and, appropriate choice of decompression technique and stabilization instruments. Enlarged transoral approaches (despite higher morbidity) are a supportive means in cases of severe basilar invagination, cranial extension of the lesion or limited jaw mobility.

Vertical translocation: the enigma of the disappearing atlantodens interval in patients with myelopathy and rheumatoid arthritis. Part I. Clinical, radiological, and neuropathological features

This statistical comparison between patients with cervical myelopathy secondary to horizontal atlantoaxial subluxation and those with vertical translocation is designed to elucidate the mechanisms responsible for cranial settling and the effect of translocation on the development of spinal cord compression. In a 10-year study of a cohort of 256 patients, 186 suffered from myelopathy and 116 (62%) of these exhibited vertical translocation according to the Redlund-Johnell criteria. Vertical translocation occurred after a significantly longer period of disease than atlantoaxial subluxation (p < 0.001). Translocation was characterized clinically by a high cervical myelopathy with features of a cruciate paralysis present in 35% of individuals compared with 26% who exhibited horizontal atlantoaxial subluxation (p = 0.29), but there was a surprising paucity of cranial nerve problems. The patients with vertical translocation had a greater degree of neurological disability (p = 0.002) and poorer survival rates (p = 0.04). Radiologically, vertical translocation was secondary to lateral mass collapse and associated with a progressive decrease in the atlantodens interval ([ADI], r = 0.4; p < 0.001) and pannus (p = 0.003). Thirty percent of patients exhibited an ADI of less than 5 mm. This phenomenon has been termed pseudostabilization. The authors' studies emphasize that the ADI (frequently featured in the literature) is totally unreliable as an indicator of neuraxial compromise in the presence of vertical translocation.

Therapeutic options and results following fixed atlantoaxial rotatory dislocations

Atlantoaxial rotatory dislocation (AARD) represents a rare pathological condition of the upper cervical spine that is frequently misdiagnosed, leading to a delay in therapy. In a long-term assessment of clinical and radiological results, three different therapeutic options with regard to the length of the dislocation-therapy interval (DTI) were evaluated. Twenty-six patients were treated for AARD from December 1988 until April 2000. Proper diagnosis was established after an average interval of 15 months. Three different therapeutical protocols were followed in order to reduce the dislocation: (1) closed transoral reposition under general anesthesia; (2) temporary transoral fixation utilizing the Harms T-plate; (3) definitive transoral fusion. The eight patients treated by closed reduction had the best pain relief. The average visual analogue scale (VAS) score was 96.6 points, while the rotatory motion of the upper cervical spine, as assessed by dynamic MRI, was 25.3 degrees to each side. The length of the dislocation-therapy-interval (DTI) averaged 1.4 months. A mean VAS Score of 92.3 points was recorded in the ten patients treated with a temporary fixation of C1/C2. In this subgroup the DTI had an average length of 5.3 months. The mean rotation to each side was 13.9 degrees . In the eight patients who underwent definitive fusion the mean VAS score was 60.6 points, while the average length of the DTI was 40.5 months. In conclusion, the clinical outcome and the subjective well-being following AARD deteriorates with increasing length of the dislocation-therapy interval.

Atlanto-axial rotatory subluxation in children: early management

Atlanto-axial rotatory subluxation (AARS) is an uncommon condition involving dislocation and abnormal fixation of the atlas on the axis. AARS is difficult to diagnose and if improperly treated it may lead to permanent neck deformity. We report a retrospective series of patients diagnosed with AARS seen during the last five years. The children presented with neck pain, head tilt, and reduction in neck mobility. In three of the cases the condition was secondary to cervical trauma and in the fourth it was associated with otitis (Grisel syndrome). The diagnosis was established by three-dimensional computerised tomography. In three cases, the atlanto-axial fixation was cured after cervical immobilisation and physiotherapy. A posterior cervical fusion was required in the remaining case. Early detection and intensive conservative treatment constitutes the mainstay of management of AARS. Surgery is reserved for cases with irreducible or recurrent subluxation.

Craniovertebral junction tuberculosis: a review of 29 cases

PURPOSE

The purpose of this work was to describe the various imaging findings in craniovertebral tuberculosis and the importance of imaging in treatment in these patients.

METHOD

A retrospective review of MR and CT scans in 29 patients with craniovertebral tuberculosis was performed. The images were reviewed, paying special attention to both bony (skull base, atlas, and axis) and soft tissue involvement in addition to atlantoaxial dislocation, lateral subluxation of the dens, and compression of the spinal cord.

RESULTS

Suboccipital pain with neck stiffness was the most common presenting symptom in our patients. The skull was involved in 19 of the 29 cases, clivus involvement was seen in 11 patients, and occipital condyle involvement was present in 14 patients. Detailed analysis of atlas involvement due to tuberculosis showed the lateral masses to be predominantly affected. The dens was involved in 18 cases (62%). Soft tissue masses in the prevertebral area were seen in 22 patients, paravertebral in 27 patients, and epidural involvement in 25 patients was identified. Atlantoaxial displacement was present in seven cases, lateral mass-dens subluxation in five, and superior subluxation of the dens through the foramen magnum compressing the medulla was seen in two cases. Spinal cord compression with intrinsic cord changes was noted in 12 cases. All patients received multidrug antituberculous therapy for 1 year. The presence of neurologic deficit and instability of the atlantoaxial complex was pivotal in further management in these patients.

CONCLUSION

A high degree of clinical suspicion is necessary when confronted with patients with neck stiffness and tenderness over the upper cervical vertebrae. MRI in these patients provides a sensitive method for the diagnosis of craniovertebral tuberculosis.

The extent of drilling in lateral approaches to the cranio-cervical junction area from a series of 125 cases

The trans-condylar approach to the craniocervical junction area (CCJA) requires a more or less extensive drilling of the two first cervical joints (C0-C1 and C1-C2). The extent of drilling necessary to resect a lesion at the CCJA was analyzed from a series of 125 cases including 114 tumours and 11 non-tumoural processes treated using a lateral approach (postero-lateral or antero-lateral) over a 15-year period (1980-1995). The extent of drilling was estimated on CT scanner axial views from the reduction of the joints surface and three groups were determined: A/less than one third B/between one third and one half, and C/more than one half. The extent of drilling was compared with the lesion location in relation to the bone limits of the CCJA: within these limits, outside them and into the bony structures. It was also analyzed with regard to pathology when separated into three groups non-osseous tumours, osseous tumours and chordomas, and non tumoural processes. Only 26 cases had a significant drilling, i.e., more than one third of the joint surfaces and of these, 14 were more than one half. In all these 14 cases, the bone structures were already invaded and 13 of them were, to some extent, beyond the bone limits of the CCJA. Of the 12 cases with drilling between one third and one half, 11 involved the bone structures and 1 was located inside the CCJA bone limits. Drilling of more than one third was required only in the case of bone lesions: 10 out of 23 bone tumours, all the 14 cases of chordomas, one case of rheumatoid arthritis and one case of C1-C2 joint spondylosis. In the other cases including mostly non-osseous tumours, drilling was limited to less than one third, though a high rate of complete removal was achieved (98%). Stabilization by arthrodesis with posterior grafting (N = 10) or by lateral bone grafting (N = 5) was achieved in all cases involving more than one half drilling, and in one case of tuberculosis. By adequately choosing the surgical approach, the extent of drilling can always be minimal. Extensive bone resection is only necessary when the tumour has already destroyed the joints. In that case, lateral or posterior fusion is an efficient technique.

Calcification of the transverse ligament of the atlas in chondrocalcinosis: computed tomography study

OBJECTIVE

To seek an association between articular chondrocalcinosis (AC) and calcification of the transverse ligament of the atlas (TLA), and to evaluate the frequency and the main computed tomography appearances of such calcification.

METHODS

Axial computed tomography slices of the cervico-occipital hinge were performed routinely in 21 patients with AC (three men, 18 women; mean age 79 years, range 67-87) and compared with those from a control group of 21 age and gender matched patients without AC.

RESULTS

Calcification of the TLA was present in 14 of the 21 patients (66%) in the AC group and in none of the 21 patients (0%) in the control group (chi 2 test: p < 0.001). Calcification was localised behind the odontoid process, inserted upon the osseous tubercles of the lateral masses of C1, and had a curvilinear profile; it varied in height (1.5 to 9 mm) and appearance (thin = < 1 mm; thick = > 1 mm) and formed either a single or a double band.

CONCLUSION

This study has demonstrated a relationship between AC and calcification of the TLA. Although such calcification often remains asymptomatic (nine of 14 patients in our study), it may be associated with attacks of acute neck pain with segmentary stiffness, fever, and an increased erythrocyte sedimentation rate, sometimes revealing AC.