Vertical Subluxation Research Articles

Early and extensive erosiveness in peripheral joints predicts atlantoaxial subluxations in patients with rheumatoid arthritis.

To study the prevalence of cervical spine subluxations and predictive factors for atlantoaxial subluxations (including anterior atlantoaxial subluxation and atlantoaxial impaction, i.e., vertical subluxation) in patients with rheumatoid arthritis (RA) who were treated early and continuously with disease-modifying antirheumatic drugs for 8-13 years. Radiographs of the cervical spine were obtained in 103 of 110 patients (the 110 surviving patients of the original 135-patient cohort) at their 8-13-year followup visits. The prevalence of cervical spine subluxations was determined. Demographic variables and the first 5-year serial data concerning disease course were analyzed in a logistic regression model to find predictive factors for atlantoaxial subluxations. Atlantoaxial subluxations were found in 14 patients (14%), and 5 patients (5%) had subaxial subluxations. Older age at baseline, greater disease activity during the first 5 years, and early erosiveness in peripheral joints predicted the development of atlantoaxial subluxations. Patients who had >or=10% of the maximum possible radiographic damage (by Larsen score) in peripheral joints at 5 years were 15.9 times more likely to develop atlantoaxial subluxations at 8-13 years than patients whose peripheral joint damage remained <10% of the maximum. Compared with historical control RA cohorts, a lower prevalence of cervical spine destruction was found in the present group of patients. Rapid erosiveness in peripheral joints was the best predictor for atlantoaxial subluxations. Extensive erosiveness in peripheral joints should alert rheumatologists to the possible development of atlantoaxial subluxations in patients with RA.

Descompresión transoral del tronco cerebral en una impresión basilar secundaria a artritis reumatoidea. Descripción de un caso y revisión de la bibliografía

The vertical subluxation or translocation of the odontoid process producing a basilar impression with compression of the brain stem is a late phenomenon in the course of rheumatoid arthritis; the appearance of symptoms in the spinal cord and the lower pairs of spinal nerves is a specific sign of this disorder. In this situation, the standard surgical aims are the decompression of the affected nerve structures followed by craniocervical stabilisation. The objective of this paper is to report on the improvement of the neurological deficit after decompressive transoral surgery (odontoidectomy), without associating any internal fixation system, in a female patient with a long history of rheumatoid arthritis and anterior compression of the brain stem caused by basilar impression and rheumatoid pannus. A survey of the literature showed that, with the odd isolated clinical case, there are no papers which describe the post operative development of surgical decompression of the brain stem carried out through an anterior approach in patients with rheumatoid subluxation of the odontoid process, without associating any internal stabilisation system. Female aged 65, diagnosed as suffering from rheumatoid arthritis at the age of 25, who was admitted with symptoms of compression of the medulla oblongata secondary to a vertical subluxation of the odontoid process. She was submitted to transoral decompression of the brain stem (odontoidectomy and removal of pannus without posterior fixation), and made surprisingly favourable post operative progress. At 15 months after the surgical decompression she led an independent life. The neurological improvement of our patient after the decompressive odontoidectomy suggests that the mechanical compression of the odontoid process with impaction of the brain stem was the predominant aetiological factor causing the symptoms in the medulla oblongata. Her clinical stabilisation, on the other hand, can be explained by a mechanism involving the spontaneous autofusion of the lateral masses of the atlas with the occipital condyle and with the axis. Lastly, we consider that, in certain cases of rheumatoid patients with atlantoaxial subluxation, impaction of the odontoid process in the foramen magnum and clinical features involving compression of the medulla oblongata, transoral decompression of the brain stem through an odontoidectomy is the choice initial surgical procedure, since it affords neurological improvement and clinical stabilisation. In any case, a strict neurological and radiological post operative follow up is needed in view of a possible craniocervical fixation occurring in the future.

Bilateral spontaneous subluxation of scleral-fixated intraocular lenses

Two young men with primary ectopic lenses had intracapsular cataract extraction and scleral fixation of posterior chamber intraocular lenses (PC IOLs) using 10-0 polypropylene sutures tied to the IOL eyelets. Three to 9 years after implantation, spontaneous IOL vertical subluxation occurred in all 4 eyes (5 IOL loops), probably because of suture breakage. Late subluxation of a sutured IOL may occur several years after implantation. Double fixation and thicker sutures should be considered, especially in young patients.

ＲＡ環軸椎脱臼患者における後方固定術前後のＭＲＩの検討

It has been suggested that MR is an excellent imaging procedure for the evaluation of rheumatoid arthritis of the cervical spine.Twelve patients (age range: 48 to 78 years, mean: 62.5 years) suffering from rheumatoid arthritis with atlantoaxial subluxation were examined with MR imaging. Conventional MR imaging was performed pre- and postoperatively. We evaluated the width and intensity of the spinal cord, reduction of periodontoid pannus and the cervicomedullary angle. Five of eight patients (62.5%) with cervical myelopathy had changes of intensity in the spinal cord. The cervicomedullary angle of the patients with vertical subluxation was significantly smaller than those without it. In patients with evidence of cervical myelopathy, the rate of decrease in cord compression improved significantly after surgery. We found the reduction of periodontoid pannus postoperatively in 33% of the patients (four out of twelve).

Prevalence of cervical lesions in rheumatoid arthritis: cross-sectional study on 263 patients

Spinal lesions in upper and sublaxilar cervical vertebrae were studied radiologically in 263 patients (25 men and 238 women) with rheumatoid arthritis (RA). Their average age was 58.9 years, and their disease duration was ranged from 6 months to 24 years (mean 13 years). Functional lateral views of the cervical spine were made. Atlantaxial subluxation (AAS) and vertical subluxation (VS) were evaluated as upper cervical lesions. Subaxilar subluxation (SAS) and endplate erosion were evaluated as subaxilar cervical lesions. One hundred and seventy-eight (67.7%) of the patients had a cervical lesion. Upper and subaxilar cervical abnormalities were recognized in 136 (51.7%) and 113 (43.0%) patients, respectively. There was no linkage between upper and subaxilar cervical lesions. While the prevalence of these lesions increased with time, the frequency was found to be over 50% within only 5 years from onset in patients with mutilating deformity. This prevalence tended to be associated with disease activity.

A long-term follow-up study of cervical lesions in rheumatoid arthritis.

To determine the natural history of cervical lesions in rheumatoid arthritis, 161 patients who had been followed for a minimum of 5 years were enrolled in this study. The average follow-up period was 10.2 years (range, 5 to 20 years). The severity of the rheumatoid arthritis was classified into three types based on the multiplicity of peripheral joint rheumatoid involvement: a least erosive subset, a more erosive subset, and a mutilating disease subset. Ninety-two patients (57%) had upper cervical involvement, which progressed in the order of anterior atlantoaxial subluxation, anterior atlantoaxial subluxation combined with vertical subluxation, and vertical subluxation alone. Subaxial subluxation was found in 18 patients (11%). In 17 of these 18 patients, upper cervical lesions were also noted. The incidence of cervical involvement in each disease subset was 39% in the least erosive group, 83% in the more erosive group, and 100% in the mutilating disease group. Fifty percent of the patients with cervical involvement had neck pain, and the remaining patients were asymptomatic. Neural involvement occurred in 10 patients. In 7 of these 10 patients, vertical subluxation of the atlas was responsible for the neural deficit. Six patients required surgical intervention because of progressive myelopathy.

Prevalence of cervical lesions in rheumatoid arthritis: cross-sectional study on 263 patients

Spinal lesions in upper and sublaxilar cervical vertebrae were studied radiologically in 263 patients (25 men and 238 women) with rheumatoid arthritis (RA). Their average age was 58.9 years, and their disease duration was ranged from 6 months to 24 years (mean 13 years). Functional lateral views of the cervical spine were made. Atlantaxial subluxation (AAS) and vertical subluxation (VS) were evaluated as upper cervical lesions. Subaxilar subluxation (SAS) and endplate erosion were evaluated as subaxilar cervical lesions. One hundred and seventy-eight (67.7%) of the patients had a cervical lesion. Upper and subaxilar cervical abnormalities were recognized in 136 (51.7%) and 113 (43.0%) patients, respectively. There was no linkage between upper and subaxilar cervical lesions. While the prevalence of these lesions increased with time, the frequency was found to be over 50% within only 5 years from onset in patients with mutilating deformity. This prevalence tended to be associated with disease activity.

Cranioventral Subluxation of the Odontoid Process With Accompanying Neo(pseudo)arthrosis in Rheumatoid Arthritis

Cervical spine involvement is a common feature in the course of long existing rheumatoid arthritis (RA).We describe a rare type of vertical subluxation with pronounced cranioventral disposition of the odontoid process and neo(pseudo)arthrosis between the skull and the tip of the odontoid processus. This 74-year-old women with RA for 40 years had progressive neck symptoms over the previous 5 years. She no longer had signs of active synovitis. Plain roentgenographs performed in a neutral position and full flexion and extension gave information about neither the osseous integrity nor the subluxation of the dens axis. Computed tomography and MR imaging techniques established the nature of the atlantoaxial and atlantooccipital joint involvement. During 2 years, this rare cranio-ventral subluxation with neo(pseudo)arthrosis seems to be rather solid, and follow up CT-images demonstrate no signs of progressive migration or suggestion of immediate fracture risk. Pronounced reduction of cervical spine mobility by long standing destructive cases of RA should always raise suspicions for cervical subluxation at the atlantoaxial level, irrespective of serological and clinical signs of rheumatoid arthritis. Vertical subluxation as seen in this patient may be missed on routine x-rays.

Collagenous Colitis and Sacroiliitis: A Case Report and Literature Review

The seronegative spondyloarthropathies commonly occur in association with such enteropathic disorders as inflammatory bowel disease, enteric infections, and Whipple's disease. Only 3 cases of collagenous colitis have been reported in association with spondyloarthropathy. We describe a 51-year-old patient with bilateral sacroiliitis and collagenous colitis, who presented with chronic, recurrent low back pain, morning stiffness, and diarrhea. As with two of the three reported cases, we describe musculoskeletal complaints preceding the onset of diarrhea. The late occurrence of suggestive diagnostic features such as diarrhea may lead to a delay in the diagnosis of a potential enteropathic arthropathy, as in our patient. All patients with chronic diarrhea should undergo appropriate evaluation with an eye for any attendant musculoskeletal features known to be potentially attributed to the resulting diagnosis. A variety of other rheumatologic and autoimmune illnesses have been described with collagenous colitis. Whether the association between collagenous colitis and seronegative spondyloarthritis is causal or casual remains to be determined. We encourage clinicians to report cases of collagenous colitis associated with spondyloarthropathy in hopes that this issue will be resolved.

Occipitocervical stabilization for myelopathy in patients with rheumatoid arthritis. Implications of not bone-grafting.

Approximately 0.9 percent of the white adult population of the United States and 1.1 percent of the adult population in Europe are affected by seropositive rheumatoid arthritis. As many as 10 percent of those patients may need an operation for atlantoaxial subluxation. Severe instability, especially when associated with vertical subluxation of the odontoid process, can result in progressive cervical myelopathy. Typically, occipitocervical fixation has been performed for these patients with use of autograft bone to achieve long-term stability through a solid fusion. Harvesting the bone graft increases the operative risk to the patient and may result in increased morbidity. In our experience, patients who have had no clear radiographic evidence of fusion following use of occipitocervical instrumentation seemed to have done as well as those who have had obvious fusion. One assumption is that the clinical improvement might be attributable simply to stabilization of the joint rather than to osseous fusion. A longitudinal study was performed on patients with rheumatoid arthritis who required an operation because of craniocervical or upper cervical instability. The results of clinical, radiographic, functional, and self-evaluations were studied to determine the efficacy of treatment and to compare the outcomes of bone-grafting with those of procedures done without bone-grafting in a group of 150 patients who underwent posterior occipitocervical stabilization with use of a contoured metal implant (a Ransford loop) that was affixed by sublaminar wires. Internal fixation was performed in 120 patients without bone-grafting and in thirty patients with use of autogenous bone-grafting. Preoperatively, 23 percent (thirty-five) of the 150 patients had mild neurological involvement (class II, according to the system of Ranawat et al.), 45 percent (sixty-eight) had objective findings of weakness and long-tract signs but were able to walk (class III-A), and 29 percent (forty-three) were quadriparetic and unable to walk (class III-B). The age of the patients at the time of the operation ranged from twelve to eighty-three years (mean, sixty-two years). There were significant improvements in postoperative Ranawat classes at all time-periods (range, p < 0.00005 to p = 0.0066) and in patient ratings of neck pain (range, p < 0.00005 to p = 0.0044) compared with preoperative scores. With the numbers available, there were no significant differences between the patients managed with a graft and those managed without grafting with respect to survival after the operation, Ranawat class, head or neck-pain rating, presence of subaxial abnormalities, radiographic craniovertebral motion, or vertical subluxation. Overall mortality at one month was 10 percent (fifteen of 150), although this value varied directly with the degree of preoperative disability. A second cervical spine operation was required in 11 percent (sixteen) of the 150 patients. While patients who have rheumatoid disease with anterior atlantoaxial subluxation should be treated with posterior atlantoaxial arthrodesis with use of bone-grafting and internal fixation, we believe that those who present with vertical instability and multi-level involvement can be treated with posterior occipitocervical stabilization with use of a contoured occipitocervical loop and sublaminar wire fixation without bone-grafting. Furthermore, we believe that the use of preoperative traction, bone cement, or a postoperative halo vest is unnecessary. Avoiding the harvesting of autogenous bone for grafting reduced the morbidity of this operation without compromising the outcome in these already sick patients.

MRI of cervical spine with flexion and extension used in patients with rheumatoid arthritis

Patients with rheumatoid arthritis (RA) often have involvement of the cervical spine. The most common abnormality is atlanto-axial subluxation (AAS). The more serious vertical subluxation (VS) is thought to develop at a later stage. Direct cord compression may occur, but the symptoms may be vague and difficult to interpret. In addition to clinical follow up, RA patients undergo several conventional radiographs of the cervical spine, with addition of flexion and extension images. This, in spite of the fact that the cervical cord and soft tissue do not show. Magnetic resonance imaging (MRI), is the modality of choice to visualize soft tissue and the cervical medulla, but is rarely performed in the follow up of RA patients. Five patients with long-standing RA, episodes of neck pain, and known AAS were asked to volunteer for a MRI study of the cervical spine, consisting of sagittal T2 weighted images of the cervical spine during flexion and extension of the neck. Compared to clinical examinations and cervical radiographs, MRI gave valuable information not otherwise obtained. The importance of MRI with the neck in a flexed and extended position is stressed. This is possible to obtain within a conventional quadrature neck coil in many RA patients.

ＭＲＩ所見から見たＲＡ頚椎病変に対する後方固定術の効果

Posterior upper cervical fusion in 13 patients with atlanto-axial subluxation caused by rheumatoid spondylitis (9 atlanto-axial anterior subluxation, 4 vertical subluxation) was assessed with magnetic resonance imaging.9 patients were treated by C1-C2 posterior fusion and 4 patients by occipital-upper cervical fusion. MRI was performed both before and after surgery. The operative results were most and least favorable in 12 patients in whom the cord indentation present before surgery disappeared after surgery, and only 1 patient in whom indentation persisted unchanged by T1-weight imaging. In T1-weight imaging after GD-DTPA was injected intravenously showing the inflamation of the synovial joints, 12 out of 13 patients showed ehhancement before surgery, and 6 patients showed persistence after surgery. In T2-weighted imaging, 4 of these patients showed high signal intensity in the spinal cord, and 3 showed unchanged persistence postoperatively.

Natural History of Upper Cervical Lesions in Rheumatoid Arthritis

The natural history of the upper cervical lesions in rheumatoid arthritis (RA) was investigated, based on a follow-up study of 79 patients. At the beginning of this study, anterior atlantoaxial subluxation (AAS) was found in 35 patients, AAS combined with vertical subluxation (VS) in 34, and VS alone in 10. During the follow-up period (mean, 6.4 years), these lesions deteriorated in 30 of the 79 patients. To evaluate the occipitoatlantoaxial relation, the angles between occiput and atlas (C0/C1 angle) and between atlas and axis (C1/C2 angle) were measured, and the correlation between these angles and deterioration of the lesions was investigated. The severity of RA was classified according to the "disease subset" advocated by one of us (T.O.): the least erosive subset (LES), the more erosive subset (MES), and the mutilating subset (MUD). There was a significant positive correlation between the C1/C2 angle and atlantodental interval (ADI) and a significant negative correlation between the C0/C1 angle and the ADI. This indicates that the atlas not only shifts forward but also slips down and forward at an incline from the axis. With an increase of the atlantal inclination, the anterior arch of atlas displaces in an anteroinferior direction, and VS combines with AAS. The development of associated VS lessens the amount of the ADI. At the advanced stage of the natural course, AAS is concealed, and VS alone is demonstrated. We concluded that the upper cervical lesion deteriorated in the order of AAS, AAS + VS, and VS alone. In patients classified as the LES subset, only AAS was found, and VS was never combined with AAS at the terminal stage. In patients in the MES, VS frequently combined with AAS. All patients who deteriorated to VS alone were ranked as MUD.

Natural course of cervical spine lesions in rheumatoid arthritis.

This study analyzed the natural course of cervical spine involvement in rheumatoid arthritis by serial radiographs. The purpose was to determine the pattern of progression of cervical spine lesions in rheumatoid arthritis and predictors for the extent of progression. Subluxation frequently occurs as a result of rheumatoid involvement of the cervical spine. It may be severe in patients with mutilans deformities in the hands and feet. The extent of progression in a given patient is still unpredictable. Serial cervical radiographs in 49 patients with rheumatoid arthritis were analyzed. The extent of progression was evaluated by rheumatoid arthritis subset defined previously, which reflected the final extent of joint erosion in this systemic disease and could be roughly classified during early stages of the disease. In the upper cervical spine, reducible anterior atlantoaxial subluxation occurred first. Vertical subluxation of the axis appeared next. Irreducible change of preceding anterior atlantoaxial subluxation was a sign of the start of vertical subluxation. In subaxial lesion, subluxation occurred less frequently (22.4%) than upper cervical lesion (77.6%). The extent of progression was different with the rheumatoid arthritis subset. In the upper cervical spine, none of the subset with least erosive disease developed vertical subluxation, whereas 52% of the subset with more erosive disease and 88% of the subset with mutilating disease advanced to vertical subluxation. The extent of progression was well correlated with the number of joints with erosion. Subaxial subluxation was often seen and became irreducible in mutilating disease and more erosive disease, but not in least erosive disease. A progressive pattern of the upper cervical subluxations was clarified. That is, upper cervical lesions progressed from reducible anterior atlantoaxial subluxation to irreducible anterior atlantoaxial subluxation with vertical subluxation. This extent of progression was different with the rheumatoid arthritis subset, which was also related to the development of subaxial subluxation. The most aggressive arthritis classification, a subset with mutilating disease, had the more severe subluxation in both upper and subaxial cervical spine.

ＲＡの頚椎病変に対する手術的治療の検討

The results of surgical treatment performed on the cervical spine of 12 patients with rheumatoid arthritis were evaluated.The mean age at the time of operation was 56.4 years (range; 44-63 years) and the mean duration of the disease was 18 years (range; 5-38). They were followed-up for a mean of 3 years 5 months (range; 4 months-6 years 6 months). llpatients achieved relief of their occipitocervical pain, and paralysis improved in seven.In two patients with atlanto-axial subluxation (AAS) and vertical subluxation (VS), cranio-cervical stabilization was performed producing good. Anterior fusion was performed in five patients with subaxial subluxation (SS), but graft compression or subluxation above or below the fused segments occurred in four patients, and two patients required further surgery. Cranio-cervical stabilization for SS, AAS, VS was performed in five patients and the results obtained were good.We regard cranio-cervical stabilization using instrumentation as useful in the treat ment of cervical spinal problems in Rheumatoid Arthritis patients.

Three-dimensional motion of the upper cervical spine in rheumatoid arthritis.

Rheumatoid arthritis frequently contributes to instability of the upper cervical spine. Rotational instability of the upper cervical spine was evaluated in rheumatoid arthritis patients using biplanar x-ray photogrammetry. Three-dimensional cervical motion and the instantaneous axis of rotation of the atlas relative to the axis were evaluated in normal and rheumatoid arthritis patients during axial rotation in the horizontal plane. Anterior atlantoaxial subluxation did not increase during axial head rotation in either the atlantoaxial subluxation or the vertical subluxation groups, while the instantaneous axes of rotation were distributed posteriorly in the dens in the RA-normal group, but were widely scattered in the atlantoaxial subluxation group.

ＲＡ頚椎病変手術症例の検討

The effects of surgical treatment for cervical spine lesions were clinically evaluated in 8 patients with Rheumatoid Arthritis (RA); mutilans type. Six patients complained of pain in the nape and occipital region, and myelopathy was noted in 3 patients. Upper cervical spine lesions were shown in 7 cases and lower in 4 cases. We performed posterior spinal fusion (CO-C2: 5 cases, C1-C2: 2 cases, below C3: 4 cases) for all patients. Posterior decompression was accompanied with posterior spinal fusion in 2 of these cases who had subaxial subluxation with cervical stenosis. Occipitocervical fusion was carried out in 1 patient with atlanto-axial subluxation in the upper cervical spine because vertical subluxation was progressing. After operation immobilization was continued using a halo-vest for an average period of 11 weeks in 7 patients with upper cervical lesions. Solid union was demonstrated radiographically in 7 except 1 patient who had died 8 months after surgery. The condition of all patients improved on early follow-up. Understanding the severity of mutilans RA, could be a better determinant for choosing the appropriate surgical treatment.

A radiological measure of shoulder subluxation in hemiplegia: its reliability and validity.

This study describes the reliability and validity of a new radiological method to measure shoulder subluxation that is based on taking a single x-ray of the affected shoulder in the plane of the scapula. A digitizer and a computer are used to quantify the measurements directly from the x-ray. One single radiological view of the shoulder taken in a standardized position provides four measures of subluxation including a measure of vertical subluxation, horizontal subluxation, a normalized distance sensitive to both vertical and horizontal subluxation, and an angular measure. A total of 72 volunteers with cerebrovascular accidents participated in the study. Thirty-six subjects had a clinical shoulder subluxation and 36 had no clinical subluxation. The construct validity analysis showed significant differences (p < .001) between the mean scores for subluxed and nonsubluxed groups on all four measures of subluxation. The concurrent validity of the x-ray measures in relation to external clinical measures (finger's breadth, measures in centimeters with calipers or a plexiglass jig) was moderate. Three measures were found to be reliable and valid whereas the fourth, a measure of horizontal subluxation has lower reliability. However, it does have clinical significance. The clinical and research implications of this study are presented.

Fusion for atlanto-axial subluxation in rheumatoid arthritis

Subluxation in the upper cervical region of the rheumatoid patient may be horizontal, vertical or both. Horizontal subluxation occurs when the odontoid peg moves backwards from its position just behind the anterior arch of the atlas (Fig 1). Vertical subluxation occurs when the odontoid moves upwards through the foramen magnum. Subluxation in either direction can give rise to pain and neurological dysfunction for which surgical stabilization is indicated. Treatment is much more frequently required for horizontal subluxation. Fusion for either horizontal or vertical subluxation is carried out under general anaesthesia with the patient prone and 2-3 kg of longitudinal traction applied via a pair of skull tongs. An incision is made in the midline longitudinally from the occipital protruberance distally for 10 cm. The muscles are raised from the spinous processes and laminae as well as from the occiput. A meticulous dissection is made of the posterior arch of the atlas and axis. The spinous process of the axis is cleared of soft tissue and a short, 2-3 cm long, Rush pin is introduced through the posterior part of the spinous process of the axis. The ends of the cerclage wire of 0.6 mm diameter are passed from below anterior to the posterior arch of the atlas (Fig. 2). The downwards loop thus formed pulls towards the spinous process of the axis gripping this below the Rush pin and the wires are then stretched posterior to the Rush pin (Fig, 3). The free ends of the cerclage are now further stretched tightening the atlas against the odontoid peg. The free ends are then passed anterior to the Rush pin and tied in a knot (Fig. 4). The stability is checked. Fig,. 5 is a lateral view of the wire arrangement.

ＲＡ下位頚椎病変のＸ線学的検討 上位頚椎固定術を行った症例を中心に

Radiographic studies of the lower cervical spine in rheumatoid arthritis (RA) were performed to investigate the influence of the fusion of the upper cervical spine upon the lower. Twenty of 54 patients treated operatively were examined. Fourteen cases with atlanto-axial anterior subluxation were treated with McGraw's procedure and 6 cases with atlanto-axial vertical subluxation were treated with occipito-atlanto-axial fusion. Normal subjects of control were 50 patients who were diagnosed as classical RA and treated conservatively.In each case, narrowing of intervertebral space without osteophyte, end-plate erosion, facet erosion, collapse of vertebral body and anterior subluxation were investigated from four roentgenograms (anteroposterior, lateral including neutral, flexion and extension). Collapse and anterior subluxation were more frequently by seen in cases of occipito-atlanto-axial fusion than in cases of McGraw's procedure and non-operative treatment. This result suggests that the fixation of occipitoatloid joint adds great force to the lower cervical spine.