273
ATLANTOAXIAL SUBLUXATION AS A COMPLICATION OF EARLY ANKYLOSING SPONDYLITIS Two Case Reports and a Review of the Literature STEVEN SORIN, ALI ASKARI, and ROLAND W. MOSKOWITZ
Atlantoaxial subluxation is uncommon in ankylosing spondylitis, especially early in the course of the disease. Two patients are described in whom atlantoaxial subluxation occurred early in the course of otherwise typical ankylosing spondylitis. The presumed mechanism is localized synovitis producing laxity or rupture of the transverse ligament. Cervical roentgenograms in maximal flexion and extension are necessary to evaluate both the degree of subluxation and the risk of cord compression. Atlantoaxial subluxation (AAS) is an infrequent, though potentially disastrous, complication of ankylosing spondylitis occurring most often in patients with long standing disease (1-12). That it can occur early in the course of the disease, in the absence of characteristic changes in the cervical spine, is not well appreciated. The following two case reports demonstrate that AAS can occur early and may even be a presenting manifestation of typical ankylosing spondylitis. From the Division of Rheumatology, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio. Steven Sorin, MD: Fellow in Rheumatology; Ali Askari, MD: Assistant Professor of Medicine; Roland W. Moskowitz, MD: Professor of Medicine. Address reprints to Roland W. Moskowitz, MD, Professor of Medicine, University Hospitals, 2073 Abington Road, Cleveland, Ohio 44106. Submitted for publication August 30, 1978; accepted in revised form September 27, 1978.
Arthritis and Rheumatism, Vol. 22, No. 3 (March 1979)
CASE REPORTS Patient 1. KS, a 20-year-old black man, came to Case Western Reserve University Student Health Service with low back pain of one year’s duration. Examination revealed sacroiliac tenderness and a flattened lumbosacral segment. Chest expansion was 1.5 inches and neck motion was mildly limited without pain. Roentgenograms of the lumbosacral spine confirmed bilateral sacroiliitis but showed no evidence of vertebral squaring or ligamentous calcification. Seven months later the patient presented with spontaneous onset of severe posterior neck pain radiating into the occipital and mastoid regions. No neurologic deficit was found. Cervical spine x-rays in a flexed position (Figure 1) revealed a 9 mm separation between the atlas and odontoid. Free motion was clearly demonstrated on gentle flexion and extension views. The apophyseal joints of the lower cervical spine showed only minimal abnormalities. Posterior fusion was performed because of continued pain and marked narrowing of the spinal canal. Patient 2. RJ, a 34-year-old seaman, came to the Cleveland VA Hospital with a 5-week history of low back and posterior neck pain radiating to the occiput and both shoulders. In the ensuing 2 weeks anterior iliac crest and bilateral shoulder pain developed. Examination revealed sacroiliac, acromioclavicular, and anterior iliac crest tenderness. Lumbosacral mobility was decreased and chest expansion was 2 inches. Paraspinal muscles in the cervical region were in severe spasm and tenderness of the C , spinous process was noted. The neck was held immobile. Lumbosacral x-rays confirmed sacroiliitis without spine involvement. A lateral film of the cervical spine in flexion (Figure 2) revealed an 8 mm atlanto-odontoid separation without other features of ankylosing spondylitis; free motion was demonstrated on flexion and extension views. HLA-B27 study was positive. Despite the subluxation, the spinal canal was 18 mm at C,, and the patient
SORIN ET AL
274
A
B
Figure LA, Flexion view of the cervical spine demonstrating 9 mm atlanto-odontoid separation and marked narrowing of spinal canal. B, Line drawing showing the relative positions of the anterior arch of the atlas, the odontoid, and posterior elements of patient 1. A 9 mm separation(A) is present between the atlas and odontoid. The posterior spinal canal (S.C.) measures 15 mm.
was treated conservatively with antiinflammatorymedication and a soft collar in anticipation of spontaneous fusion. Neither patient has developed clinical features of psoriasis, Reiter’s syndrome, or colitis.
DISCUSSION Atlantoaxial subluxation is an uncommon complication of ankylosing spondylitis. Wilkinson and Bywaters followed 212 such patients for up to 15 years (10). Only one of their patients developed AAS. These authors concluded that “spinal fracture and subluxation rarely complicate ankylosing spondylitis.” Of approximately 1,000 patients seen at a spondylitis clinic, Sharp and Purser discovered only 17 cases of AAS. They reported, in 1961, on these cases plus 5 additional patients drawn from other sources (4). Eighteen of these patients had typical ankylosing spondylitis and 4 had ankylosing spondylitis with “atypical features.” Cervical pain and limitation of motion had been present for at least 3 years prior to subluxation in 16 of 17 patients in whom
this information was available. Spinal mobility was grossly restricted in 15. These cases are consistent with other reports where AAS is said to occur in the setting of advanced, but active, disease (1-3,5-11). Case 19 in the series by Sharp and Purser is relevant in that the patient developed atlantoaxial subluxation 4 years before the onset of back pain and limitation. Features of the disease were noted to be “atypical” of pure ankylosing spondylitis, and the patient went on to develop psoriatic skin lesions (4). A more recent article (1 3) reported a man with severe ankylosing spondylitis who, 27 years after the diagnosis, developed psoriasis and dactylitis. This man suffered severe destruction and upward subluxation of the axis eventually producing medullary compression. Neither of our patients has as yet developed psoriatic skin lesions although further followup will be necessary to exclude this possibility. The articular facets are nearly horizontal between the atlas and axis (1 1) and stability of this articu-
ATLANTOAXIAL SUBLUXATION
275
Motion at the atlantoaxial articulation and consequent narrowing of the spinal canal can only be adequately evaluated with cervical roentgenograms taken in positions of maximal flexion and extension. The findings in our patients suggest that these views should be obtained even in the patient with early ankylosing spondylitis who develops new or atypical neck pain. Neurologic manifestations of cord compression rarely occur with a spinal canal dimension greater than 16 mm at the C, level (16). Since healing of fractures and dislocations is not delayed in ankylosing spondylitis (17), our current approach is to treat these patients conservatively so long as there are no objective neurologic abnormalities and the spinal canal is at least 16 mm wide with the neck maximally flexed. Experience with a larger number of patients will be necessary to establish more definitive guidelines for medical and surgical management.
REFERENCES 1. Werne S: Studies in spontaneous atlas dislocation. Acta
Orthop Scand suppl23:1-150, 1957 2. Martel W: The occipito-atlanto-axial joints in rheumatoid arthritis and ankylosing spondylitis. Am J Roengenol
86:223-240, 1961 3. Martel W, Page JW: Cervical vertebral erosions and subFigure 2. Flexion view of the cervical spine showing 8 rnrn at-
lanto-odontoid separation. Note widely patent spinal canal.
lation depends on the transverse ligament which holds the dens taut to the anterior arch of the atlas (1,2). Synovial tissue surrounds the dens both anteriorly and posteriorly (2,3). This synovium as well as the transverse ligament may be the site of inflammation in either rheumatoid arthritis or ankylosing spondylitis. Synovial hyperemia, thickening and proliferation with plasma cell and lymphocytic infiltration occur and may produce laxity or rupture of the transverse ligament (9,14). With laxity or rupture, movement is established at the atlantoaxial level (1 1). Odontoid erosion or “whittling” has been observed in ankylosing spondylitis (2,15). If severe, the shortened odontoid can slide beneath even an intact transverse ligament. Erosion of the dens is usually a late phenomenon in ankylosing spondylitis and was not seen in our patients.
luxations in rheumatoid arthritis and ankylosing spondylitis. Arthritis Rheum 3546-556, 1960 4. Sharp J, Purser DW: Spontaneous atlanto-axial dislocation in ankylosing spondylitis and rheumatoid arthritis. Ann Rheum Dis 20:47-77,1961 5. Stammers FAR, Birrn MB, Frazier P: Spontaneous dislocation of the atlas. Lancet 2:1203-1205, 1933 6. Kornblum D,Clayton M, Nash HH: Nontraumatic cervical dislocations in rheumatoid spondylitis. JAMA
149:431435, 1952 7. Pratt TLC: Spontaneous dislocation of the atlanto-axial articulation occurring in ankylosing spondylitis and rheumatoid arthritis. J Fac Radio1 10:4043, 1959 8. Morrison RJG: Discussion on some aspects of ankylosing spondylitis. Proc Royal SOCMed 48:204-207, 1955 9. Margulies ME, Katz I, Rosenberg M: Spontaneous dislocation of the atlanto-axial joint in rheumatoid spondylitis. Neurology 5:290-294, 1955 10. Wilkinson M,Bywaters EGL: Clinical features and course of ankylosing spondylitis. Ann Rheum Dis 17:209-228,
1958
H,Stewart WA: Spontaneous atlanto-axial dislocation. N Engl J Med 269677-681, 1961
11. Lourie
SORIN ET AL
276
12. Katz WA: Ankylosing spondylitis, Rheumatic Diseases, Diagnosis and Management. Edited by WA Katz. Philadelphia, JB Lippincott, 1977, pp 520-539 13. Little H, Swinson DR, Cruickshank B: Upward subluxation of the axis in ankylosing spondylitis. Am J Med 60279-285, 1976 14. Cruickshank B: Pathology of ankylosing spondylitis. Clin Orthop Related Res 74:43-58, 1971
15. Martel W: Radiology in the rheumatic diseases, Arthritis and Allied Conditions. Edited by JL Hollander and DJ McCarty. Philadelphia, Lea and Febiger, 1972, p 90 16. Bohlman H: Atlanto-axial subluxation (abstract). Orthop Trans 1:3, 1978 17. Hansen ST, Taylor TK, Honet JC, et a1 Fracture dislocations of the ankylosed thoracic spine in rheumatoid spondylitis. J Trauma 7:827-837, 1967
Policy Changes In order to accommodate the increased number of letters-to-the-editor and the requests o f many readers for more clinical articles, the Journal will begin using a new format called Brief Reports. Authors may submit short case reports, discussions o f interesting disease associations, and, rarely, preliminary scientific reports. The same editorial policies regarding quality o f manuscripts will apply; all such articles will be subjected to the reviewer process.
letters-to-the-Editor should be no more than 4 double-spaced manuscript pages, including references. These should be limited to commentaries on previous articles and issues affecting rheumatology or the American Rheumatism Association.
Arthritis and Rheumatism i s now published every month. Subscription rates for 1979 are $35.00 for nonmembers within the U.S., $40.00 for nonmembers outside the U.S., and $20.00 for students, fellows, interns, and residents.
ATLANTOAXIAL SUBLUXATION AS A COMPLICATION OF EARLY ANKYLOSING SPONDYLITIS Two Case Reports and a Review of the Literature STEVEN SORIN, ALI ASKARI, and ROLAND W. MOSKOWITZ
Atlantoaxial subluxation is uncommon in ankylosing spondylitis, especially early in the course of the disease. Two patients are described in whom atlantoaxial subluxation occurred early in the course of otherwise typical ankylosing spondylitis. The presumed mechanism is localized synovitis producing laxity or rupture of the transverse ligament. Cervical roentgenograms in maximal flexion and extension are necessary to evaluate both the degree of subluxation and the risk of cord compression. Atlantoaxial subluxation (AAS) is an infrequent, though potentially disastrous, complication of ankylosing spondylitis occurring most often in patients with long standing disease (1-12). That it can occur early in the course of the disease, in the absence of characteristic changes in the cervical spine, is not well appreciated. The following two case reports demonstrate that AAS can occur early and may even be a presenting manifestation of typical ankylosing spondylitis. From the Division of Rheumatology, Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio. Steven Sorin, MD: Fellow in Rheumatology; Ali Askari, MD: Assistant Professor of Medicine; Roland W. Moskowitz, MD: Professor of Medicine. Address reprints to Roland W. Moskowitz, MD, Professor of Medicine, University Hospitals, 2073 Abington Road, Cleveland, Ohio 44106. Submitted for publication August 30, 1978; accepted in revised form September 27, 1978.
Arthritis and Rheumatism, Vol. 22, No. 3 (March 1979)
CASE REPORTS Patient 1. KS, a 20-year-old black man, came to Case Western Reserve University Student Health Service with low back pain of one year’s duration. Examination revealed sacroiliac tenderness and a flattened lumbosacral segment. Chest expansion was 1.5 inches and neck motion was mildly limited without pain. Roentgenograms of the lumbosacral spine confirmed bilateral sacroiliitis but showed no evidence of vertebral squaring or ligamentous calcification. Seven months later the patient presented with spontaneous onset of severe posterior neck pain radiating into the occipital and mastoid regions. No neurologic deficit was found. Cervical spine x-rays in a flexed position (Figure 1) revealed a 9 mm separation between the atlas and odontoid. Free motion was clearly demonstrated on gentle flexion and extension views. The apophyseal joints of the lower cervical spine showed only minimal abnormalities. Posterior fusion was performed because of continued pain and marked narrowing of the spinal canal. Patient 2. RJ, a 34-year-old seaman, came to the Cleveland VA Hospital with a 5-week history of low back and posterior neck pain radiating to the occiput and both shoulders. In the ensuing 2 weeks anterior iliac crest and bilateral shoulder pain developed. Examination revealed sacroiliac, acromioclavicular, and anterior iliac crest tenderness. Lumbosacral mobility was decreased and chest expansion was 2 inches. Paraspinal muscles in the cervical region were in severe spasm and tenderness of the C , spinous process was noted. The neck was held immobile. Lumbosacral x-rays confirmed sacroiliitis without spine involvement. A lateral film of the cervical spine in flexion (Figure 2) revealed an 8 mm atlanto-odontoid separation without other features of ankylosing spondylitis; free motion was demonstrated on flexion and extension views. HLA-B27 study was positive. Despite the subluxation, the spinal canal was 18 mm at C,, and the patient
SORIN ET AL
274
A
B
Figure LA, Flexion view of the cervical spine demonstrating 9 mm atlanto-odontoid separation and marked narrowing of spinal canal. B, Line drawing showing the relative positions of the anterior arch of the atlas, the odontoid, and posterior elements of patient 1. A 9 mm separation(A) is present between the atlas and odontoid. The posterior spinal canal (S.C.) measures 15 mm.
was treated conservatively with antiinflammatorymedication and a soft collar in anticipation of spontaneous fusion. Neither patient has developed clinical features of psoriasis, Reiter’s syndrome, or colitis.
DISCUSSION Atlantoaxial subluxation is an uncommon complication of ankylosing spondylitis. Wilkinson and Bywaters followed 212 such patients for up to 15 years (10). Only one of their patients developed AAS. These authors concluded that “spinal fracture and subluxation rarely complicate ankylosing spondylitis.” Of approximately 1,000 patients seen at a spondylitis clinic, Sharp and Purser discovered only 17 cases of AAS. They reported, in 1961, on these cases plus 5 additional patients drawn from other sources (4). Eighteen of these patients had typical ankylosing spondylitis and 4 had ankylosing spondylitis with “atypical features.” Cervical pain and limitation of motion had been present for at least 3 years prior to subluxation in 16 of 17 patients in whom
this information was available. Spinal mobility was grossly restricted in 15. These cases are consistent with other reports where AAS is said to occur in the setting of advanced, but active, disease (1-3,5-11). Case 19 in the series by Sharp and Purser is relevant in that the patient developed atlantoaxial subluxation 4 years before the onset of back pain and limitation. Features of the disease were noted to be “atypical” of pure ankylosing spondylitis, and the patient went on to develop psoriatic skin lesions (4). A more recent article (1 3) reported a man with severe ankylosing spondylitis who, 27 years after the diagnosis, developed psoriasis and dactylitis. This man suffered severe destruction and upward subluxation of the axis eventually producing medullary compression. Neither of our patients has as yet developed psoriatic skin lesions although further followup will be necessary to exclude this possibility. The articular facets are nearly horizontal between the atlas and axis (1 1) and stability of this articu-
ATLANTOAXIAL SUBLUXATION
275
Motion at the atlantoaxial articulation and consequent narrowing of the spinal canal can only be adequately evaluated with cervical roentgenograms taken in positions of maximal flexion and extension. The findings in our patients suggest that these views should be obtained even in the patient with early ankylosing spondylitis who develops new or atypical neck pain. Neurologic manifestations of cord compression rarely occur with a spinal canal dimension greater than 16 mm at the C, level (16). Since healing of fractures and dislocations is not delayed in ankylosing spondylitis (17), our current approach is to treat these patients conservatively so long as there are no objective neurologic abnormalities and the spinal canal is at least 16 mm wide with the neck maximally flexed. Experience with a larger number of patients will be necessary to establish more definitive guidelines for medical and surgical management.
REFERENCES 1. Werne S: Studies in spontaneous atlas dislocation. Acta
Orthop Scand suppl23:1-150, 1957 2. Martel W: The occipito-atlanto-axial joints in rheumatoid arthritis and ankylosing spondylitis. Am J Roengenol
86:223-240, 1961 3. Martel W, Page JW: Cervical vertebral erosions and subFigure 2. Flexion view of the cervical spine showing 8 rnrn at-
lanto-odontoid separation. Note widely patent spinal canal.
lation depends on the transverse ligament which holds the dens taut to the anterior arch of the atlas (1,2). Synovial tissue surrounds the dens both anteriorly and posteriorly (2,3). This synovium as well as the transverse ligament may be the site of inflammation in either rheumatoid arthritis or ankylosing spondylitis. Synovial hyperemia, thickening and proliferation with plasma cell and lymphocytic infiltration occur and may produce laxity or rupture of the transverse ligament (9,14). With laxity or rupture, movement is established at the atlantoaxial level (1 1). Odontoid erosion or “whittling” has been observed in ankylosing spondylitis (2,15). If severe, the shortened odontoid can slide beneath even an intact transverse ligament. Erosion of the dens is usually a late phenomenon in ankylosing spondylitis and was not seen in our patients.
luxations in rheumatoid arthritis and ankylosing spondylitis. Arthritis Rheum 3546-556, 1960 4. Sharp J, Purser DW: Spontaneous atlanto-axial dislocation in ankylosing spondylitis and rheumatoid arthritis. Ann Rheum Dis 20:47-77,1961 5. Stammers FAR, Birrn MB, Frazier P: Spontaneous dislocation of the atlas. Lancet 2:1203-1205, 1933 6. Kornblum D,Clayton M, Nash HH: Nontraumatic cervical dislocations in rheumatoid spondylitis. JAMA
149:431435, 1952 7. Pratt TLC: Spontaneous dislocation of the atlanto-axial articulation occurring in ankylosing spondylitis and rheumatoid arthritis. J Fac Radio1 10:4043, 1959 8. Morrison RJG: Discussion on some aspects of ankylosing spondylitis. Proc Royal SOCMed 48:204-207, 1955 9. Margulies ME, Katz I, Rosenberg M: Spontaneous dislocation of the atlanto-axial joint in rheumatoid spondylitis. Neurology 5:290-294, 1955 10. Wilkinson M,Bywaters EGL: Clinical features and course of ankylosing spondylitis. Ann Rheum Dis 17:209-228,
1958
H,Stewart WA: Spontaneous atlanto-axial dislocation. N Engl J Med 269677-681, 1961
11. Lourie
SORIN ET AL
276
12. Katz WA: Ankylosing spondylitis, Rheumatic Diseases, Diagnosis and Management. Edited by WA Katz. Philadelphia, JB Lippincott, 1977, pp 520-539 13. Little H, Swinson DR, Cruickshank B: Upward subluxation of the axis in ankylosing spondylitis. Am J Med 60279-285, 1976 14. Cruickshank B: Pathology of ankylosing spondylitis. Clin Orthop Related Res 74:43-58, 1971
15. Martel W: Radiology in the rheumatic diseases, Arthritis and Allied Conditions. Edited by JL Hollander and DJ McCarty. Philadelphia, Lea and Febiger, 1972, p 90 16. Bohlman H: Atlanto-axial subluxation (abstract). Orthop Trans 1:3, 1978 17. Hansen ST, Taylor TK, Honet JC, et a1 Fracture dislocations of the ankylosed thoracic spine in rheumatoid spondylitis. J Trauma 7:827-837, 1967
Policy Changes In order to accommodate the increased number of letters-to-the-editor and the requests o f many readers for more clinical articles, the Journal will begin using a new format called Brief Reports. Authors may submit short case reports, discussions o f interesting disease associations, and, rarely, preliminary scientific reports. The same editorial policies regarding quality o f manuscripts will apply; all such articles will be subjected to the reviewer process.
letters-to-the-Editor should be no more than 4 double-spaced manuscript pages, including references. These should be limited to commentaries on previous articles and issues affecting rheumatology or the American Rheumatism Association.
Arthritis and Rheumatism i s now published every month. Subscription rates for 1979 are $35.00 for nonmembers within the U.S., $40.00 for nonmembers outside the U.S., and $20.00 for students, fellows, interns, and residents.
