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Study Design: Retrospective review of 13 cases with craniovertebral tuberculosis treated conservatively., Objective: To evaluate the results of conservative treatment of craniovertebral tuberculosis and compare with the literature., Summary of Background Data: Craniovertebral tuberculosis is a rare entity even in endemic countries, and there is no consensus in the literature regarding conservative or surgical management for the same. Reports range from radical surgery to totally conservative approach. We report our experience in treating such patients conservatively., Methods: A retrospective review of 13 patients diagnosed with craniovertebral tuberculosis was performed. All patients were treated conservatively with cervical traction for initial 3 months followed by a brace along with multidrug antitubercular drugs for 18 months., Results: All patients responded favorably to conservative treatment. Follow-up averaged 43 months (range, 16-65 months). No patient deteriorated neurologically. All patients had symptomatic improvement. Failure to reduce atlantoaxial dislocation/lateral subluxation of the dens completely was seen in 2 cases., Conclusions: We think that all patients with craniovertebral junction tuberculosis can be managed adequately using conservative means regardless of the extent of bony destruction with a good patient outcome. Surgery should be reserved for only a selective few where diagnosis is in doubt and there is initial severe or progressive neural deficit with/without respiratory distress in presence of documented mechanical compression and documented dynamic instability following conservative treatment.

Object: Atlantoaxial and occipitocervical instability in children have traditionally been treated with posterior bone and wire fusion and external halo orthoses. Recently, successful outcomes have been achieved using rigid internal fixation, particularly C1-2 transarticular screws. The authors describe flow diagrams created to help clinicians determine which method of internal fixation to use in complex anatomical circumstances when bilateral transarticular screw placement is not possible., Methods: The records of children who underwent either atlantoaxial or occipitocervical fixation with rigid internal fixation over an 11-year period were retrospectively reviewed to define flow diagrams used to determine treatment protocols., Results: Among the 95 patients identified who underwent atlantoaxial or occipitocervical fixation, the craniocervical anatomy in 25 patients (six atlantoaxial and 19 occipitocervical fixations [26%]) required alternative methods of internal fixation. Types of screw fixation included loop or rod constructs anchored by combinations of C1-2 transarticular screws (15 constructs), C-1 lateral mass screws (11), C-2 pars screws (24), C-2 translaminar screws (one), and subaxial lateral mass screws (six). The mean age of the patients (15 boys and 10 girls) was 9.8 years (range 1.3-17 years). All 22 patients with greater than 3-month follow-up duration achieved solid bone fusion and maintained stable constructs on radiographic studies. Clinical improvement was seen in all patients who had preoperative symptoms., Conclusions: Novel flow diagrams are suggested to help guide selection of rigid internal fixation constructs when performing pediatric C1-2 and occipitocervical stabilizations. Use of these flow diagrams has led to successful fusion in 25 pediatric patients with difficult anatomy requiring less common constructs.

Unlabelled: Sacral agenesis is an uncommon condition characterised by total or partial absence of the sacrum. The association of this condition with craniocervical junction abnormalities is extremely rare., Case Report: We describe a 3-year-old girl who, at the age of 8 months, while being investigated for short stature, was found to have significant craniocervical instability associated with anomalies of the odontoid peg. In addition to this she had partial sacral agenesis but genetic tests showed a normal karyotype. Due to the inherent difficulty of surgical fixation and immobilisation in an infant of her age, she was managed conservatively in a soft cervical orthosis. At the age of three years, surgery for decompression and stabilisation was deemed necessary due to the onset of neurological morbidity., Conclusion: The authors describe this extremely rare association and discuss the difficulties faced while deciding the optimum surgical strategy for managing such young children with craniocervical instability.

Objective: Arachnoid cysts (ACs) of the craniocervical junction are extremely rare entities. This report describes a craniocervical junction AC with unusual clinical course at an unusual anatomical location., Methods: A 21-year-old man was admitted to our clinic after a craniospinal trauma. Examination was unremarkable. Computed tomography scans demonstrated mild to moderately enlarged third and the lateral ventricles, but the fourth ventricle was typically normal. Neuroimaging studies obtained after the onset of clinical symptoms revealed marked enlargement of the ventricular system and a new cyst formation at the C1-2 level which was absent before. He underwent suboccipital craniectomy and C1-2 laminectomies. The cyst was fenestrated into subarachnoid space., Results: He made a good recovery. The histopathological diagnosis was confirmed as AC., Conclusion: Due to rarity of this clinical entity, we urge readers to keep in mind the possibility of the development of this kind of AC with unusual clinical course.

Objectives: To evaluate the role of dynamic magnetic resonance imaging (MRI) in craniovertebral junction (CVJ) abnormalities., Materials and Methods: Twenty-five patients with suspected CVJ abnormalities underwent dynamic MRI of the CVJ, and in 20 of these patients, noncontrast computed tomography scan of the CVJ was done. The images were evaluated for atlantoaxial instability (AAI), spinal canal narrowing, cord compression, presence of altered cord signal intensity, and bony abnormalities in neutral, flexion, and extension., Results: Dynamic MRI detected 15 cases of AAI (10 fixed and 5 mobile AAI), 21 patients had varying degrees of spinal canal narrowing. Five patients showed increased narrowing on flexion/extension. Two patients demonstrated direct cord compression in flexion, whereas in neutral position, only dural compression was seen. One patient had cord compression on extension that was not seen in neutral or flexed position., Conclusion: Dynamic MRI was able to detect cases of cord compression that were not seen in neutral position and was diagnostic in all cases of mobile AAI where mobility at this joint affects the treatment options. Dynamic MRI is extremely useful for evaluating craniovertebral junction abnormalities and, in particular, cord compression.

Intraoperative monitoring is considered as a useful tool to prevent neurological damage during different neurosurgical procedures. Somatosensory evoked potentials (SEP) allow simultaneous assessment of several cortical and sub cortical centers. In this case presentation, we report intraoperative monitoring of an elderly patient with craniovertebral junction meningioma. Tibial SEP responses were elicited by stimulation of the tibial nerve; the recordings were visually analyzed for the presence of the main peaks P40-N50, peak to peak amplitudes, peak latencies and compared to baseline recordings throughout the procedure. During decompression from the medial aspect of the medulla SEP responses were lost for a brief period of time. Surgeons achieved total tumor removal and the patient left the operating room without any neurological deficit.

Objective: To investigate the qualitative diagnosis method of atlanto-axial tuberculosis and the corresponding therapeutic strategy., Methods: Twenty-two cases with atlanto-axial tuberculosis proven by histopathologic diagnosis were observed. Three cases and 17 cases underwent trans-oral biopsy and CT-guide percutaneous biopsy respectively, 2 cases were conformed by frozen section in operation. Thirteen of the 22 cases underwent surgical therapy: 1 case with anterior trans-oral radical eradication and fusion under Halo-vest immobilization, 7 cases with anterior cervical radical eradication, 1 case with anterior interbody fusion and titanic plate fixation, 2 cases were with posterior atlantoaxial interlaminar fusion and 2 cases with posterior cervical occipito-axial titanic plate internal fixation and fusion. Other 9 cases accepted nonsurgical therapy: 8 cases with Halo-vest immobilization and 1 case with head halter traction. All cases were given appropriate antituberculotic chemotherapy for 12-18 months., Results: All of the 22 cases were followed up, and the average time was 37 month. The lesion focus showed reparation and fusion in X-ray, and the results were satisfactory., Conclusions: Biopsy can acquire the qualitative diagnosis on atlanto-axial tuberculosis. The choice of therapy is made on the situation of cold abscess, pathological fracture, atlanto-axial dislocation and spinal cord compression.

Object: The authors measured relevant quantitative anatomical parameters to define safety zones for the placement of C-1 posterior screws., Methods: Nineteen linear, two angular, and four surface parameters of 20 dried atlantal specimens were evaluated. The Optotrak 3020 system was used to define the working area. Ideal angles for screw positioning were measured using digital radiographs and a free image-processing program. Six silicone-injected cadaveric heads were dissected bilaterally to study related neurovascular anatomy. The depth (range 5.2-9.4 mm, mean 7.2 +/- 1.1 mm) and width (range 5.2-8.1 mm, mean 6.5 +/- 0.9 mm) of the transverse foramen varied considerably among specimens. The mean posterior working area was 43.3 mm2. All specimens accommodated 3.5-mm-diameter screws, and 93% accepted 4-mm-diameter screws. In 10 specimens (50%), partial removal of the posterior arch was necessary to accommodate a 4-mm screw. The mean maximum angle of medialization was 16.7 +/- 1.3 degrees; the mean maximum superior angulation was 21.7 +/- 4.7 degrees., Conclusions: The anatomical configuration of the atlas and vertebral artery (VA) varied considerably among the cadaveric specimens. The heights of the C-1 pedicle, posterior arch, and posterior lamina determine the posterior working area available for screw placement. The inferior insertion of the posterior arch may have to be drilled to increase this working area, but doing so risks injury to the VA. A dense venous plexus with multiple anastomoses may cover the screw entry site, potentially obscuring the operative view and increasing the risk of hemorrhage.

Background: An alternative technique of atlantoaxial fixation is described, which combines the trans-articular method of fixation described by Magerl in 1982 and the interarticular technique described by us in 1988., Methods: Between January 2001 and January 2005, 18 patients underwent the discussed method of fixation at the Department of Neurosurgery at King Edward VII Memorial Hospital in Mumbai, India. Fifteen patients had congenital craniovertebral anomaly and 3 patients had posttraumatic atlantoaxial instability. Fourteen patients had basilar invagination with "fixed" atlantoaxial dislocation, and 4 patients had mobile and reducible atlantoaxial dislocation. The mean follow-up period was 22 months (range, 3-50 months)., Results: Successful atlantoaxial stabilization was achieved in all patients and was documented with dynamic radiography. There was no incidence of implant rejection. There were no neurological, vascular, or infective complications., Conclusion: The described method of atlantoaxial fixation that incorporates the advantages of the 2 currently more frequently used techniques of lateral mass fixation could be an alternative method of fixation.

Background: During development of the axis, four different ossification centers are formed. The two cranial ossification centers are demarcated from the ossification center of the vertebral corpus by a subdental synchondrosis. During further development the subdental synchondrosis--which is thought to close spontaneously--might not close completely, which leads to the necessity for differentiating synchondrotic remnants from a fracture at the base of the dens (type II according to Anderson and D'Alonzo)., Results: To characterize the architecture of the axis with particular attention to the subdental synchondrosis, the axis was harvested from 36 age- and gender-matched patients covering the human aging process from adolescence to senescence. In all specimens bone mineral density (BMD) was measured by peripheral quantitative computed tomography (pQCT). Morphological analysis after undecalcified processing of all specimens revealed a persistency of the subdental synchondrosis in 87% of all patients. Histological characterization of the subdental synchondrosis showed a cartilaginous structure interspersed with focal mineralization. Furthermore, static histomorphometric analysis revealed that trabecular bone volume and cortical thickness were significantly reduced within the base of the axis as compared to the dens and the corpus, respectively., Conclusion: Taken together, these results provide evidence that the base of the axis is a structurally distinct region. Besides well-recognized biomechanical aspects, these results suggest that the structure of the base of the axis might contribute to the occurrence of fractures of the axis and offer an additional explanation for the observation of nonunion after type II dens fractures.

Background: Deposition of CPPD crystals occurs in the fibrous and hyaline cartilage of the joints and intervertebral disks of the spine. Half of patients known to have chondrocalcinosis had asymptomatic calcification in the odontoid region. The cases of 12 patients with a spinal cord syndrome secondary to CPPD deposition in the odontoid region were published in the literature. In all those cases, the mass lesion was extradural in location with good outcome after surgical decompression via the transoral route., Case Description: We report on a rare case of large periodontoid CPPD deposition causing cervicomedullary compression, erosion of the overlying bone, and underlying dura with intradural extension and vertebral artery encasement., Conclusions: Calcium pyrophosphate dihydrate is a rare cause of cervicomedullary compression. Intradural extension of periodontoid CPPD has not been reported on.

We report the case of a 55 year old man with osteomyelitic destruction of the odontoid process and a parapharyngeal abscess. The patient was admitted with diagnosis of meningitis and degenerative cervical spine disease without compression of spinal cord or nerve roots but progressive impairment of cervical spine mobility. Inflammatory parameters in serum and cerebrospinal fluid were detected and antibiotic therapy was initiated resulting in subjective improvement of symptoms. When impairment of cervical spine motility persisted and gait disturbance developed, a parapharyngeal abscess and an osteomyelitic destruction of the odontoid process caused by infection with staphylococcus aureus was diagnosed. After cleavage of the abscess and four months of antibiotic therapy the gait disturbance disappeared and mild impairment of cervical spine motility persisted.

Background: Anterior screw fixation provides the best anatomical and functional results for odontoid process fracture (type II and "shallow" type III) with intact transverse ligament. The purpose of this study is to evaluate the clinical results of the 4.5-mm-diameter cannulated Herbert screw in the anterior odontoid fixation., Methods: From May 2003 to November 2005, 20 consecutive cases of types II and III odontoid process fractures were treated with anterior screw fixation using a 4.5-mm Herbert screw. The Herbert screw has double threads, with different pitches on the distal and proximal ends. It has no head, so it can be inserted through articular cartilage and buried below bone surface., Results: There were 16 male and 4 female patients whose ages ranged from 15 to 76 years (mean, 43.7 years). The fracture type was type II-A in 4 patients, II-N in 9 patients, II-P in 5 patients, and III in 2 patients. The range of follow-up was 3 to 36 months (mean, 18.6 months). There were an overall bone fusion rate in 17 cases (85%), fibrous union in 1 (5%), and nonunion in 2 (10%). Overall, complication unrelated to hardware occurred in the one (postoperative dysphagia) without complication-related hardware failure., Conclusions: The Herbert screw is very useful in anterior fixation for types II and III odontoid process fractures. This series showed successful clinical results comparable with that of the 3.5-mm cannulated cancellous screw and distinct advantages over conventional screws in the aspect of biomechanical properties and less invasiveness.

Retroodontoid or periodontoid pseudotumor unassociated with rheumatoid arthritis or hemodialysis is clinically rare. The authors report three cases of retroodontoid pseudotumor that they treated surgically. All patients exhibited myelopathy of the upper cervical spinal cord. Plain radiography depicted atlantoaxial instability in two of the three patients. Spinal cord compression caused by a mass lesion in all patients was clearly demonstrated on magnetic resonance images. In two patients, the mass lesion was not limited to the retroodontoid region and expanded continuously to the cranial base. Posterior laminectomy of the atlas and occipitocervical fusion were performed. After surgery, the pseudotumor disappeared in two cases and was clearly reduced in one case, and neurological symptoms also improved. Retroodontoid pseudotumor is a lesion for which symptomatic improvement can be expected with posterior decompression and fusion, even without direct tumor excision.

The presence of an atlantoaxial degenerative articular cyst is rare; when present this lesion extends posteriorly to the dens, causing cervicomedullary compressive myelopathy. The authors describe a symptomatic case of this lesion associated with atlantoaxial subluxation in a 76-year-old man. The patient's neurological symptoms resolved and corresponded to a reduction in the size of the cyst. After 8 months of continued conservative treatment, in which the patient wore a Philadelphia collar, the cyst spontaneously regressed. Subsequently, a C1-2 posterior fusion was performed to treat the atlantoaxial subluxation.

Background: A few studies have reported the relation between the atlantoaxial (C1/2) angle and cervical alignment (C2-C7) angle after a Magerl and Brooks (M&B) surgical procedure to treat atlantoaxial subluxation (AAS) in patients with rheumatoid arthritis (RA). However, no study has examined an optimum preoperative C1/2 angle reduction. We aimed to assess the relation between the C1/2 angle reduction and the C2-C7 angle change in patients with progressive RA who underwent the M&B procedure., Methods: We retrospectively analyzed the relation between the preoperative C1/2 angle and C2-C7 angle in 28 consecutive RA patients using their clinical and radiological data. Differences in the preoperative and postoperative C1/2 and C2-C7 angles were detected. Correlations of these angles and the reduced degree of angles were examined. The Ranawat grading scale and Japanese Orthopaedic Association (JOA) scores were used to determine myelopathy. Pain was categorized into five categories according to severity. Clinical and X-ray evaluations were collected before surgery, at 3 and/or 6 months after surgery, and at final follow-up., Results: Clinical symptoms, Ranawat grade, and JOA scores improved postoperatively, and patients achieved bony union within 3 months. We observed a strong and significant correlation between the reduced C1/2 angle and the change in the C2-C7 angle. Patients with a preoperative C1/2 angle of <20 degrees had markedly reduced cervical lordotic angle but this condition was not seen in patients with a preoperative C1/2 angle of >or=20 degrees . The optimum C1/2 angle was estimated as [20 degrees - (preoperative C1/2 angle)] in patients with a C1/2 angle <20 degrees or as an in situ angle in patients with a C1/2 angle of >or=20 degrees ., Conclusions: Surgeons performing the M&B procedure need to select patients carefully and avoid complete or overreduction of the C1/2 angle to prevent serious postoperative SAS and myelopathy.

The authors report the cases of four patients in whom they diagnosed an extremely rare and hitherto unreported clinical condition-unilateral hypertrophy of the C-1 lateral mass causing symptomatic cord compression. All patients presented with long-standing torticollis and progressive myelopathy. Three patients underwent posterior decompressive surgery and one underwent resection of the part of the lateral mass invading into the spinal canal and subsequent atlantoaxial plate and screw fixation. Clinical improvement of varying degrees occurred in all cases following surgery. The clinical recovery, however, was most remarkable in the patient who underwent resection of the bone portion indenting the cord. The follow-up periods ranged from 2 to 14 years. The remarkable similarity in the presenting clinical and radiological/neuroimaging features in all four patients suggests that unilateral hypertrophy of the lateral mass of atlas may be a defined clinical entity. The treatment strategy needs to be evaluated; however, resection of the compression-causing portion of the hypertrophic bone appears to be the best treatment option.

Introduction: Some authors pointed out that there were more than a few patients with inadvertent C2-C3 union after C1-C2 posterior fusion, although few detailed studies of C2-C3 union have been reported. The purpose of this study was to clarify whether C2-C3 union accelerated adjacent C3-C4 disc degeneration after C1-C2 posterior fusion and to investigate the related factors for C2-C3 union., Methods: Sixteen patients with rheumatoid arthritis (RA group) (4 males, 12 females, mean age 60 years, mean follow-up period 4 years and 3 months) and fifteen patients without RA (non-RA group) (11 males, 4 females, mean 52 years, mean follow-up period 3 years and 10 months) who underwent C1-C2 posterior fusion were radiologically assessed. The C2-C3 union was defined as trabecular bone formation at C2-C3 interlamina in lateral radiograph. C3-C4 disc height was measured to evaluate the disc degeneration., Results: C2-C3 union rate was 56% and 60% in RA group and non-RA group, respectively. In RA group, postoperative C3-C4 disc height was lower (Student's t-test, P = 0.029) and the decrease rate of C3-C4 disc height was higher (Student's t-test, P = 0.015) in patients with C2-C3 union than in patients without C2-C3 union. In non-RA group, the age at operation was older (Student's t-test, P = 0.0007), and the C1-C2 fusion angle (Student's t-test, P = 0.012) was smaller in patients with C2-C3 union than in patients without C2-C3 union., Conclusions: C2-C3 union after C1-C2 posterior fusion occurred in more than half of both groups. Inadvertent C2-C3 union should be considered a radiological complication and a potential risk factor due to acceleration of C3-C4 disc degeneration in RA.

Background: Rheumatoid arthritis is a chronic inflammatory disease, which affects 1% of the population. Hands and feet are most commonly involved followed by the cervical spine. The spinal column consists of vertebrae stabilized by an intricate network of ligaments. Especially in the upper cervical spine, rheumatoid arthritis can cause degeneration of these ligaments, causing laxity, instability and subluxation of the vertebral bodies. Subsequent compression of the spinal cord and medulla oblongata can cause severe neurological deficits and even sudden death. Once neurological deficits occur, progression is inevitable although the rapidity of progression is highly variable. The first signs and symptoms are pain at the back of the head caused by compression of the major occipital nerve, followed by loss of strength of arms and legs. The severity of the subluxation can be observed with radiological investigations (MRI, CT) with a high sensitivity. The authors have sent a Delphi Questionnaire about the current treatment strategies of craniocervical involvement by rheumatoid arthritis to an international forum of expert rheumatologists and surgeons. The timing of surgery in patients with radiographic instability without evidence of neurological deficit is an area of considerable controversy. If signs and symptoms of myelopathy are present there is little chance of recovery to normal levels after surgery., Design: In this international multicenter randomized clinical trial, early surgical atlantoaxial fixation in patients with rheumatoid arthritis and radiological abnormalities without neurological deficits will be compared with prolonged conservative treatment. The main research question is whether early surgery can prevent radiological and neurological progression. A cost-effectivity analysis will be performed. 250 patients are needed to answer the research question., Discussion: Early surgery could prevent serious neurological deficits, but may have peri-operative morbidity and loss of rotation of the head and neck. The objective of this study is to identify the best timing of surgery for patients at risk for the development of neurological signs and symptoms.

Object: Clinicoradiological differences and outcome following surgery in pediatric patients (< or = 16 years of age) with congenital irreducible atlantoaxial dislocation (IAAD) and reducible atlantoaxial dislocation (RAAD) were analyzed., Methods: Ninety-six patients (57 with IAAD and 39 with RAAD) were categorized as follows: Grade I, no deficits except hyperreflexia or neck pain (six patients); Grade II, minor deficits but independent for activities of daily living (25); Grade III, partially dependent (30); and Grade IV, totally dependent (35). Patients with RAAD underwent direct posterior fusion, and those with IAAD were treated with transoral decompression and posterior fusion. Patients with good outcomes included those who could walk unaided, with improvement in spasticity and weakness, and those who maintained Grade I status. The category of poor outcome included patients with the following conditions: postoperative deterioration or lack of improvement; inability to ambulate regardless of neurological improvement at a minimum follow-up duration of 3 months; or perioperative death. A significantly higher incidence of C-1 assimilation, C2-3 fusion, asymmetrical occiput-C2 facet joints, and basilar invagination were seen in patients with IAAD, and os odontoideum was noted in those with RAAD (p < 0.05). A good outcome was recorded in 35 patients with IAAD and 22 with RAAD, whereas 14 with IAAD and nine with RAAD had a poor outcome (eight patients in each category were lost to follow up)., Conclusions: Radiological differences in the anatomy of patients with IAAD and those with RAAD may be due to improper segmentation of the occipital and upper cervical sclerotomes in the former and dysfunction of the transverse ligament in the latter. A significantly better outcome was noted in completely dependent patients with IAAD compared with those with RAAD. Respiratory compromise was an important prognostic factor.

The authors describe the cases of three children in whom atlantoaxial instability was caused by os odontoideum, all requiring surgical fixation. Although C1-2 rod/cantilever constructs involving C-2 pedicle screws and C1-2 transarticular screws have been widely applied in adults, only C1-2 transarticular screw fixation has been reported in children. Both of these constructs potentially place the vertebral artery (VA) at risk because of the variable location of the transverse foramen. Atlantoaxial fixation with C-2 translaminar screws has recently been reported in adult cases in which the risk of VA injury was reduced. The authors report the successful results of rigid atlantoaxial fixation in three children in whom bilateral crossing C-2 translaminar screws were placed, and they discuss the possible advantages of this technique in the pediatric population.

Conservative treatment is reported in a child with atlantoaxial rotatory fixation. Three-dimensional (3D) computerized tomography (CT) and magnetic resonance (MR) imaging demonstrated the degree of dislocation and alar ligament damage. A rigid cervical collar and muscle relaxant agents without any traction allowed full recovery. Control 3D CT scanning and MR imaging findings are reported.

Rigid fixation of the axis with C1-2 transarticular screws or C-2 pedicle screws results in high fusion rates but remains technically demanding because of the risk of injury to the vertebral artery (VA) and the limitations imposed by anatomical variability. Translaminar fixation of the axis with crossing bilateral screws provides rigid fixation and is technically simple, is not affected by variations in individual anatomy, and does not place the VA at risk. The long-term results in 20 patients treated with translaminar fixation for craniocervical, atlantoaxial, and axial-subaxial instability are presented, with 100% fusion rates and no neurological or vascular complications. Translaminar screws may be a good option for rigid fixation of the axis for surgeons not proficient in the more technically demanding methods of stabilization.

To explore the many osseous irregularities that are found in the area between the basiocciput, the anterior arch of the atlas and the tip of the dens axis we studied 99 cadaver specimens using magnetic resonance tomography (MRT), computed tomography (CT), median saw-cut sections, and histological sections. Additionally, "dry" specimens of the skull (n = 110), atlas (n = 56), and axis (n = 33) were investigated. In the median plane, the dry and cadaver specimens exhibited osteoarthritis-related osseous outgrowths and osteophytes of the articular surfaces of the median atlanto-axial joint (n = 63), and the presence of congenitally developed free ossicles (n = 22) and of third occipital condyles (n = 3). The largest osteophytes (giant osteophytes) (n = 4) of the anterior arch of the atlas formed osseous contact zones with the basiocciput that were visible histologically as real joints and were designated accessory median atlanto-occipital joints. The third occipital condyles also formed osseous contact zones, visible histologically as real joints, with the anterior arch of the atlas or with the tip of the dens, and were designated accessory atlanto-occipital or occipito-odontoid joints. Frequent free ossicles, incorporated into the accessory joint, were found by histological examination to be covered with hyaline cartilage., (Copyright 2005 Wiley-Liss, Inc)

The axial spondyloarthritis (SpA) is the most important disease out of the whole group of SpA. If a sacroiliits is clearly detectable by x-rays a diagnosis of ankylosing spondylitis can be made. However, there is still a delay of 5-10 years from the first symptoms until a final diagnosis is made. An important reason for this is the fact that radiological changes are often only detectable after several years of disease, despite the presence of inflammation as detected by MRI and the presence of clinical manifestations such as pain and stiffness. An early diagnosis becomes more and more important because effective therapies have become available which are probably even more effective if given early. New strategies how to make an early diagnosis and how primary care physicians can screen for these patients are discussed.

Objective: This is Part II of a study on atlantoaxial rotatory fixation (AARF) that aims to introduce a new diagnostic paradigm and a new classification of this condition based on motion analysis of C1C2 rotation using computed tomographic (CT) imaging. This phase of the study is possible because Part I succeeded in defining physiological C1C2 axial rotation with CT data from 21 normal children, displayed in a highly concordant composite motion curve, which is used as the normal template for the present study. AARF is defined as flagrant departure from normal motion dynamics as delineated by abnormal motion curves. The new classification is predicated on the graded amount of pathological stickiness in the restricted rotation., Methods: Forty children age 1.5 to 14 years with painful "cock-robin" necks resulting from minor trauma or otolaryngological procedures were subjected to 3 CT examinations: 1) in the presenting (P) position; 2) with the nose pointing up (P0 position); and 3) with the head forcefully turned to the opposite side as much as the patient could tolerate (P&#95; position). The angles made by C1 and C2 and the separation angle C1C2 degrees (C1 minus C2 degrees) were obtained as described in Part I. The test motion curve was generated by plotting C1 against C1C2 angles, and all motion curves were analyzed in the context of the normal template., Results: Five distinct groups with highly characteristic motion curves could be identified. Group 1 (n = 5) patients showed essentially unaltered ("locked") C1C2 coupled configurations regardless of corrective counterrotation, with curves that are horizontal lines in the upper two quadrants of the template. Group 2 (n = 7) patients had reduction of the C1C2 separation angle with forced correction, but C1 could not be made to cross C2. Their curves slope downward from right to left in the upper quadrants but never traverse the x axis. Group 3 (n = 9) patients showed C1C2 crossover, but only when the head was cranked far to the opposite side. Their motion curves traverse the x axis left of C1 = -20 degrees. Groups 1, 2, and 3 motion dynamics are respectively classified as Types I, II, and III AARF in descending degree of pathological stickiness, which is in essence a resistance against closure of the C1C2 angle to counterrotation. Group 4 (n = 14) patients had normal dynamics, and Group 5 (n = 5) patients showed motion curve features between normal and Type III AARF, designated as belonging to the diagnostic gray zone, an uncertain group that may or may not revert to normal dynamics with only comfort measures., Conclusion: AARF can be reliably diagnosed with a simple and practical CT protocol and construction of a three-point motion curve superimposed on a reusable normal template. The type of AARF, reflective of the severity of pathological stickiness of rotation, can be identified readily by the shape of the motion curve. This system of classification is useful in selecting the best regimen of management.

Objective and Importance: A 31-year-old woman presented with an avulsion fracture of the foramen magnum via bilateral occipital condyles with extension through the inferior aspect of the clivus., Clinical Presentation: The patient had no neurological deficits and was initially immobilized in a halo brace., Intervention: To preserve rotational motion at C1-C2, we performed an occiput-to-C1 fusion with bilateral C1 lateral mass screws attached with rods to occipital keel screws. Postoperatively, the patient remained neurologically intact. Three-month follow-up imaging revealed no abnormal motion. Follow-up computed tomographic scan showed an intact construct and bony fusion., Conclusion: This rare injury, a bony variant of occipitoatlantal dislocation, was successfully treated with a unique occiput-to-C1 fusion.

Object: The aim of this study was to audit the treatment of symptomatic atlantoaxial instability in Down syndrome and to assess factors associated with fusion failure in this group of patients., Methods: The authors reviewed the cases of 12 children with Down syndrome presenting with symptomatic atlantoaxial instability who underwent surgery for internal fixation and fusion. A review of clinical histories, radiological investigations, and details of operative interventions was also performed. The mode of presentation was acute spinal cord injury (five cases), progressive myelopathy (four cases), and neck pain or stiffness (three cases). The atlantodental interval ranged from 5 to 13 mm. The posterior atlantodental interval at the C-1 level was 9.5 mm (range 6-11 mm). In 10 patients an os odontoideum was present. Translocation of the odontoid process occurred in one patient, and occipitoatlantal instability was also identified in two cases. Twenty-four operations were performed in the 12 patients. A transoral odontoidectomy was required in four children. Successful fusion was demonstrated in seven patients at the first operation. Three of the five patients with acute cord injury made significant functional recovery and were left with no or mild disability., Conclusions: Additional bone abnormalities at the CVJ are common in the Down syndrome population. Young age at the time of fusion and multiple osseous anomalies pose a higher risk factor in fusion failure. The authors recommend an aggressive surgical approach for management of symptomatic cases of CVJ instability.

We present a case of traumatic vertical atlantoaxial dislocation of 16 millimetres with a fatal outcome. We hypothesize that this extremely rare traumatic vertical atlantoaxial dislocation results from insufficiency of the C1/C2 facet capsules after rupture of the tectorial membrane and the alar ligaments.

Os odontoideum can lead to instability of the atlantoaxial joint and places the spinal cord at significant risk for acute catastrophic events after minor trauma or chronic neurological change. We present two cases of os odontoideum in pediatric patients that were not appreciated at earlier remote imaging but were, in retrospect, detectable. One patient presented with an acute spinal cord injury. Incorporating assessment of dens integrity into the evaluation algorithm for all pediatric cervical spine studies should lead to early detection of os odontoideum lesions and allow referral to appropriate clinical spinal services for evaluation, surveillance and possible surgery to prevent future complications.

Study Design: Case report., Objectives: To present a case of complete osteolysis of the dens and accompanying luxation of the atlantoaxial joint, on the basis of a Staphylococcus aureus infection., Summary of Background Data: To date, complete osteolysis of the dens followed by atlantoaxial dislocation has only been reported as a rare complication in patients with tuberculosis but not as secondary to a Staphylococcus aureus infection., Methods: Because of emerging neurological complications in both upper extremities, we chose closed reduction and temporary Halo-fixation together with appropriate antibiotic coverage as primary treatment followed by an operative stabilization with Magerl fusion (Galli fusion combined with transarticular screw fixation of C1 and C2)., Results: After the operative procedure (Magerl fusion), immediate pain relief was achieved as well as almost complete resolution of neurological deficits., Conclusions: To our knowledge, this presents the first reported case of a complete destruction of the dens, as a result of a purulent bacterial infection leading to atlantoaxial luxation. Our case demonstrates that infections of the atlantoaxial region are difficult to diagnose and are seen mostly in immunocompromised patients, such as patients with diabetes. Furthermore, it proves that other infections besides tuberculosis can lead to complete osteolytic destruction of the atlantoaxial joint.

Radiography, computed tomography (CT), and magnetic resonance imaging exams of the cervical spine were performed in a 29-year-old man who was ultimately diagnosed with an orthotopic os odontoideum during admission for injuries sustained in a motor vehicle collision. Initial radiography suggested either os odontoideum or an acute fracture of the dens. Further imaging with CT and flexion and extension radiographs confirmed os odontoideum and excluded a dens fracture. Although rare, os odontoideum is an important cervical spine anomaly to consider and to distinguish from an acute fracture of the dens.

Objective: To investigate the frequency and the severity of radiological cervical spine involvement in patients with rheumatoid arthritis (RA)., Methods: We investigated 165 consecutive unselected patients with RA who fulfilled the revised American College of Rheumatology criteria for RA. All patients had a complete physical and laboratory evaluation. Patients had a radiological evaluation that included hand and wrist radiographs, as well as cervical spine radiographs in anteroposterior, lateral, and lateral in full flexion views. Hand radiographs were evaluated according to the Larsen criteria, while cervical radiographs were evaluated according to Winfield classification., Results: There were 143 women and 22 men, with a mean age of 59.6 +/- 12.5 and disease duration 12.3 +/- 13.9 years. Positive rheumatoid factor was found in 63.6% of patients. One hundred forty-six patients presented radiological findings related to cervical spine involvement: atlantoaxial subluxations were found in 20.6% and erosions of the odontoid process in 2.4%; none presented vertical subluxation. Subaxial subluxations were found in 43.6%, disc space narrowing at C2-C3, C3-C4, C4-C5 levels in 66.1%, and vertebral plate sclerosis and erosions in 43.6%., Conclusion: Cervical spine radiological involvement is a frequent finding in our patients with RA, but the severity of the disease is rather mild, possibly related to the ethnic background.

Study Design: Case report., Objective: To report a case of ossification of the posterior atlantoaxial membrane (PAAM) and ossification of the transverse ligament of the atlas (TAL)., Summary of Background Data: Ossification of the PAAM and TAL are both very rare clinical entities. This is the first case involving ossification of both the PAAM and TAL with the development of cervical myelopathy., Methods: Patient's history, physical examination, radiographic evaluation, surgical treatment, and outcome are examined. Relevant literature is also reviewed., Results: The patient's neurological symptoms significantly improved after posterior decompressive surgery., Conclusion: Ossification of various parts of the spinal ligament have been reported previously. Among them, ossification of both the PAAM and TAL has never been reported previously and is thus extremely rare. Surgical intervention improved the neurological impairment.

Non-invasive imaging methods are increasingly entering the field of forensic medicine. Facing the intricacies of classical neck dissection techniques, postmortem imaging might provide new diagnostic possibilities which could also improve forensic reconstruction. The aim of this study was to determine the value of postmortem neck imaging in comparison to forensic autopsy regarding the evaluation of the cause of death and the analysis of biomechanical aspects of neck trauma. For this purpose, 5 deceased persons (1 female and 4 male, mean age 49.8 years, range 20-80 years) who had suffered odontoid fractures or atlantoaxial distractions with or without medullary injuries, were studied using multislice computed tomography (MSCT), magnetic resonance imaging (MRI) and subsequent forensic autopsy. Evaluation of the findings was performed by radiologists, forensic pathologists and neuropathologists. The cause of death could be established radiologically in three of the five cases. MRI data were insufficient due to metal artefacts in one case, and in another, ascending medullary edema as the cause of delayed death was only detected by histological analysis. Regarding forensic reconstruction, the imaging methods were superior to autopsy neck exploration in all cases due to the post-processing possibilities of viewing the imaging data. In living patients who suffer medullary injury, follow-up MRI should be considered to exclude ascending medullary edema.

The authors describe an alternative method of C1-2 joint distraction, reduction, and fixation in the treatment of 24 patients with fixed atlantoaxial dislocation. Based on their results, they conclude that there is a place for reduction of fixed atlantoaxial dislocation and subsequent fixation in a procedure that does not require removal of any osseous spinal element.

We report three cases of tectorial membrane injury in children. An increased interspinous ratio was identified on cervical spine radiographs. The tectorial membrane injuries were diagnosed by magnetic resonance imaging. The three children were restrained passengers in high-speed motor vehicle accidents, and all sustained polytrauma. Two children with partial tears of the tectorial membrane were immobilized in a halo, and one with a longitudinal tear of the tectorial membrane had an occiput-to-C2 fusion.

The aim of this study was to explore whether reported pain and functional disability in whiplash-associated disorders (WAD) patients is associated with lesions to specific soft tissue structures in the upper cervical spine, as assessed by MRI. Pre-selected structures for MRI assessment included the alar ligaments, the transverse ligament, the tectorial and the posterior atlanto-occipital membranes. The questionnaire employed was a modification of the Oswestry Low Back Pain Index. It was comprised of ten single items related to pain and activity of daily living. Ninety-two whiplash patients and 30 control persons, randomly drawn, were included. WAD patients reported significantly more pain and functional disability than the controls, both for total score and each of the ten single items. In the WAD patients, MRI lesions to the alar ligaments showed the most consistent association to the reported pain and disability. Lesions to other structures often occurred in combination with lesions to the alar ligaments. Lesions to the transverse ligament and to the posterior atlanto-occipital membrane also appeared to be related to the NDI score, although the association was weaker than for the alar ligament. The disability score increased with increasing number of abnormal (grade 2-3) structures. These results indicate that symptoms and complaints among WAD patients can be linked with structural abnormalities in ligaments and membranes in the upper cervical spine, in particular the alar ligaments.

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 displacement is known to be a cause of childhood torticollis and may as well be responsible for chronic neck pain after rear-end automobile collisions. The objective was to determine whether quantification of C2 malrotation is possible by plain radiographs in comparison to CT as the golden standard. MR imaging was evaluated as to whether it was of equal value in the detection of bony landmarks. C2 vertebra of five human cadaveric cervical spine specimens, ligamentously intact, were rotated using a Steinmann pin in steps of 5 degrees up to 15 degrees right and 15 degrees left. Plain radiographs, CT and MRI images were taken in each rotational step. Data were analyzed for quantification of C2 rotation by three independent examiners. A rotation of 5 degrees led to a spinous process deviation (SPD) from the midline of 3 mm as measured on an a.p. plain radiograph. A coefficient of rotation was calculated (1.62 degrees mm(-1)). Data analyzed by three examiners revealed a small coefficient of variation (0.03). MRI and CT measurements showed comparable results for the quantification of rotation; however, in both techniques the 15 degrees rotation was underestimated. Quantification of upper cervical spine malrotation was possible on plain radiographs using the SPD and a rotation coefficient. MRI and CT were equally successful in the assessment of C2 malrotation.

The authors describe the case of a traumatic C-1 ring fracture and transverse ligament injury in an otherwise healthy adult woman; the lesion was essentially untreated for 3 months and resulted in basilar invagination. On presentation 3 months postinjury, the patient complained of severe increasing suboccipital pain and a grinding sensation in her upper neck. Axial computerized tomography (CT) scans revealed a C-1 ring fracture, basilar invagination with the dens abutting the clivus, and significant lateral splaying of the C-1 lateral masses. Flexion-extension radiography demonstrated abnormal motion at the atlantoaxial junction. A unique surgical technique was used to address simultaneously the C1-2 instability, the displaced C-1 fracture, and basilar invagination without having to perform occipital fixation. The authors believe that an understanding of the mechanism of the cranial settling in this case (further splaying of the C-1 lateral masses and downward migration of the occipital condyles) permitted full reduction of the deformity; this was accomplished by performing a horizontal reduction of the C-1 lateral masses, using direct C-1 lateral mass screws, a rod compressor, and a cross-link. Postoperative CT scanning confirmed the success of reduction. The results in this report highlight a rare but important complication of untreated C-1 fracture and ligament disruption, and the authors describe a novel treatment technique with which to restore vertical alignment and preserve occipital C-1 motion. A variation of this technique may also be used to treat Type II transverse ligament injuries associated with C-1 ring fractures as an alternative to halo immobilization.

Study Design: Case report., Objective: To report a rare traumatic C1-C2 dislocation associated with fracture of the anterior arch of the atlas in a neurologically intact patient., Summary of Background Data: Isolated fractures of the anterior arch of C1 are very rare. There have been reports of horizontal fractures of the anterior arch thought to occur secondary to hyperextension injuries with subsequent avulsion of the anterior tubercle of the atlas. To our knowledge, however, there are no previously reported cases of isolated anterior arch fractures of C1 associated with posterolateral dislocation of the C1-C2 articulation., Methods: A 53-year-old patient who presented with a posterolateral dislocation of the C1-C2 articulation and an associated anterior arch fracture of C1 is reported. Details of the initial presentation, diagnostic strategy, and initial and definitive management are provided., Results: Closed reduction with halo ring application and gentle manipulation was followed with definitive internal fixation consisting of Magerl C1-C2 transarticular screw fixation coupled with modified Brooks fusion., Conclusions: Posterolateral C1-C2 dislocation associated with atlantal anterior arch fracture is a rare injury that can be effectively treated with gentle closed reduction under fluoroscopic guidance followed by internal fixation with or without halo vest immobilization. Recognition of associated conditions including vertebral artery compromise, concomitant cervical spine fractures, and life-threatening injuries is paramount to the successful treatment of these patients.