Archives of Orthopaedic and Traumatic Surgery
Arch Orthop Traumat Surg 93, 243-248 (1979)
©J F Bergmann Verlag 1979
An Alternate Method for Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation Bo Althoff and Ian F Goldie Department of Orthopaedic Surgery, Sahlgren's Hospital, University of G 6teborg, G 6teborg, Sweden
Summary A modification of common methods is described for fixation of anterior and inferior atlantoaxial dislocation (AAD and IAD) In AAD a wire is passed around the atlas arch and knotted around the spinous process of the axis in a way that a figure 8 arrangement is achieved as seen in the lateral view. In IAD a wire is passed through holes in the occiput and knotted around the spinous process of the axis A rectangular bone graft is inserted between the occiput and the spinous process of the axis, thus preventing further inferior dislocation. In both methods methyl methacrylate and bone grafts are as a rule added for further long-time stabilization. The methods have been used in 15 cases of AAD and in three cases of IAD On radiologic examination with attention focused on the immediate postoperative fixation the follow-up time has been three months The long-time results of fixation have been recorded with a follow-up time of six years The fixation proved to be satisfactory in 14 patients with AAD and in the three patients with IAD The clinical results were good in the 14 patients with AAD and in the three with IAD.
A serious complication in cervical involvement in rheumatoid arthritis is a dislocation in the atlantoaxial articulation The atlas can be dislocated anteriorly and with the odontoid process remaining stationary the spinal canal becomes narrowed The function of the spinal cord may be endangered A separation between the atlas and the odontoid process exceeding 3 mm (with further separation in flexion) is regarded as pathological In rheumatoid arthritis this occurs in about 20 % (Sharp and Purser, 1961 ; Martel et al , 1963 ; Cibert, 1969 ; Mathews, 1969 ; Dirheimer, 1977).
A dislocation can also develop vertically with the atlas and occiput descending on the odontoid process which thus passively enters through the foramen occipitale magnum into the skull This occurs in about 7 % (Davies and Markley, 1951 ; Storey, 1952 ; Sharp and Purser, 1961 ; Bland et al , 1963; Martel et al , 1963 ; Webb et al , 1968 ; Mathews, 1969 ; Rana and Taylor, 1971 ; Dirheimer, 1977). When anterior separation over 3 mm is present in the atlanto-axial joint surgical intervention has been suggested in particular if pain and/or neurological symptoms appear related to this region The aim is to stabilize the joint. For treatment of a so-called vertical dislocation, surgical procedures have also been suggested when pain and/or neurological symptoms appear and then it is also aimed at stabilization. Various methods for stabilization have been described, all of which have in common to block the occiput, the atlas, and the axis or the two latter only. Fixation can be achieved by the passage of wires around the skeletal structures with application of bone grafts, and methyl-methacrylate is suggested for further reinforcement. The principles of a stabilizing procedure have been described by Brattstr 6 m and Granholm (1976) who reported on occipito-cervical fusion in 28 patients with rheumatoid arthritis Wires were passed through holes in the occiput and anterior to the posterior arch of the atlas They were knotted over a Rush-pin inserted transversely in the spinous process of the axis For additional stabilization, methyl-methacrylate was placed around the wire over one half of the vertebral arches This rendered a stability permitting early mobilization For a more permanent and biologic fixation bone grafts were placed over the roughened 0344-8444/79/0093/0243/$ 1 20
244
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
surfaces of the other half of the vertebral arches. Excluding the occiput a similar method has been suggested by Gallie ( 1939) and modifications thereof by Brooks ( 1978). The stabilization procedures in vertical dislocation are very much the same as those for the anterior dislocation. In this report we intend to propose a simplified method for fixation which yields satisfactory stabilization and good clinical results The procedures as we have developed them will be described for anterior and vertical (downward) dislocation, respectively Before entering on the description of the methods and their results, definitions of the pathoanatomical conditions will be presented.
Definitions Anterior Atlanto-axial Dislocation (AAD) = anterior (forward) dislocation of the atlas in relation to the odontoid process Separation exceeding 3 mm is regarded as pathological The separation increases on bending the head forwards It is, however, important to measure the distance between the posterior margin of the odontoid process and the anterior border of the posterior arch of the atlas This latter space is subjected to individual variation. Inferior Atlanto-axial Dislocation (IAD) = inferior (downward) dislocation of the atlas on the articular facets of the axis The odontoid process then protrudes through the occipital foramen into the skull The degree of dislocation is measured by the distance between the tip of the odontoid process and a line combining the hard palate with the most caudal point of the occipital curve More than 4 5 mm may be considered pathological (Martel and Page, 1960).
Methods
Fig 1 A Posterior view of the atlas and axis to illustrate the passage of wire for fixation The wire ends are passed on both sides from below anterior to the posterior atlas arch and curved posteriorly in a distal direction A wire loop is formed posterior to a Rush-pin introduced through the spinous process of the axis
Fig 1 B Same as Fig 1 a with wire ends knotted anterior to the Rush-pin and at the base of the spinous process of the axis
For anterior atlanto-axialdislocation the following method has been used The patient has been placed on the operating table in the prone position Traction has not been applied to the cervical column After Lidocaine® injection into the skin to diminsh bleeding a longitudinal incision is made from the 5th cervical spinous process to the occiput The muscles are detached from the spinous processes and vertebral arches The arch of the atlas is carefully dissected taking care not going too laterally for fear
Fig 2 Oblique posterior view of the atlas and the axis The black line on the odontoid process demonstrates fracture line For fixation a wire has been pulled around the arches in a figure of 8 A Rush-pin has been passed through the spinous process of the axis
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
245
Fig 3 A Radiograph of flexion in cervical spine with anterior dislocation of the atlanto-axial joint in rheumatoid arthritis B Wire in figure of 8 fixation of dislocation illustrated in Fig 3 A. Atlanto-axial reduction has been obtained with the atlas pressed against the odontoid process The space between the spinous processes is diminished
of injuring the vertebral artery A wire is introduced from below on one side of the midline in front of the posterior arch of the atlas It is then pulled through the atlanto-occipital space The other end of the wire is proceeded with in the same way on the opposite side A loop has now been formed of the wire in a distal direction and this loop is passed over (posterior to) a Rush-pin of 3 cm which has been drilled transversely through the posterior part of the spinous process of the axis (Figs 1 a, b). The free ends of the wire are knotted at the base of the spinous
process of the axis and thus a loop of 8 has been accomplished (Fig 2) Before knotting the wire ends the atlas is pulled posteriorly for stabilization against the odontoid process (Figs. 3 a, b) In cases where the bone is brittle and does not permit pulling of the wire this can be retained without pull and then act as a stabilizer for the cement If the atlas cannot resist the pull of the wire, bone only can be transplanted and external fixation applied In most cases, however, the wire can be applied as described and once this has been achieved methyl methacrylate
Fig 4 A-D A Lateral radiograph of inferior atlanto-axial dislocation B Lateral tomogram of the atlas and the axis indicating degree of inferior atlanto-axial dislocation in Fig 4 A. C Radiograph of fixation of inferior atlanto-axial dislocation with wire through holes in the occiput and knotted over a Rush-pin introduced through the spinous process of the axis Asterisk indicates the corticocancellous bone graft which blocks further inferior dislocation. D Oblique view of 4 C
246
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
Material Since 1972 thirty-three patients have been treated surgically for atlanto-axial dislocation Twenty-three of these suffered from classical rheumatoid arthritis and ten from other conditions. These conditions consisted of one acute fracture of the odontoid process, five non-united fractures of the odontoid process, four os odontoideum and one patient with rupture or elongation of the transverse ligament.
Rheumatoid Arthritis (n = 23)
Fig 4E Posterior view of the occiput, the atlas, and the axis A bone block has been interposed between the occiput and the spinous process of the axis and secured by a steelwire over a Rush-pin
is placed from the occiput down over the spinous processes to the axis and also moulded into the wires for better stabilization not only in flexion-extension but also in rotation The cortical surfaces of the occiput, the atlas, the axis, the third, and at times also the fourth vertebra are roughened with a dentist's drill. Cancellous bone from the iliac bone is then placed over these rough areas two drainages are introduced and the suturing is done in layers Postoperatively, the patient receives a soft collar for a week or two (in cases without wires: hard collar for three months) The patient is mobilized the day after the operation. Inferior atlanto-axial dislocation is treated surgically with the patient placed on the operating table in the prone position and the procedure is carried out in the same way as is described above The fixation is done as follows Two holes are drilled through the occiput one on each side of the midline about 1 cm from the posterior border of the occipital foramen This should not cause any conflict with the transverse sinus The posterior arches are prepared as described above A block of bone in the form of a rectangle is taken from the iliac bone One of the short sides is placed against the occiput anterior to the drilled holes. The opposite short side is cut out in its middle so that the block can be pressed down over the atlas and axis arches with the spinous process of the axis penetrating through the prepared slit in the bone block The block thus achieves an appearance like a pair of trousers with each trouser leg on either side of the spinous process A wire is now introduced through the holes of the occiput and pulled down and knotted over a Rush-pin around the spinous process of the axis posterior to the bone block which thus becomes pressed against the arches of the vertebrae (Figs 4 a-d) The cancellous side of the bone block rests against the arches Cement is applied over the midline involving the wire for immediate and stable fixation Cancellous bone chips are further placed around the bone block on the previously roughened posterior surfaces of the arches Two drainages are applied and suturing is carried out in layers Also in these cases a soft collar is given for 1-2 weeks and mobilization starts on the day after operation.
Preoperative radiologic examination showed dislocation of the atlas in all 23 cases The dislocation was between 5 mm and 17 mm In addition, three patients had an inferior dislocation. Eight were men and 15 were women The age at operation was between 36 and 73 years with a median age of 56 years All patients had severe occipital pain and 17 had signs which could be ascribed to spinal cord compression In 20 patients the fusion involved only the atlas and the axis In three additional cases the occiput was involved. Other Conditions (n = 10) The age at operation of these patients was between 15 and 73 years with a median age of 37 years Seven were men and three were women Eight patients had signs of spinal cord compression One patient with an os odontoideum had after a traffic accident long-lasting cervical pain and mobility between his os odontoideum and axis The last patient was an acute odontoid fracture which was unstable In nine patients a fusion between the atlas and the axis was performed In one additional patient with an os odontoideum the occiput was involved In this patient the posterior arch of the atlas had been removed 17 years earlier.
Follow-Up All 33 patients were examined clinically and radiographs were taken in flexion and extension of the cervical spine at least three months after the operation This was done in an attempt to analyze the efficacy of the stabilizing procedure on a short-time basis Twenty-three patients were followed and reexamined for one year or more after the operation Six patients had died at the time of follow-up No death had any relation to the operation or to the disease in the upper cervical spine The causes of death were renal failure in three patients, cardiac infarction in one, cerebral hemorrhage in one and a metastatic carcinoma from the kidney in one patient. Definition of ClinicalResults Good: free of pain and preoperative neurologic deficit eliminated or much reduced. Fair : less pain Preoperative neurologic deficit partly reduced. Rheumatoid Arthritis (Table 1) Four patients were operated by putting in bone-chips only as the atlas could not resist the pull of the wire One was healed satisfactorily as judged by the radiographs There was mobility
247
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation Table 1 Radiologic and clinical results of different methods of fixation in atlanto-axial dislocation in rheumatoid arthritis Method for fixation
Number of patients
Radiologic examination in flexion and extension
Clinical results
No mobility Mobility healed not healed
Good
Bone-chips
4
1
Stainless steel wire + bone-chips
5
5
14
13
Stainless steel wire + bone-chips + methyl-methacrylate
3
3 5
1
Fair
13
1 -
1
Table 2 Radiologic and clinical results of different methods of fixation in odontoid fracture, os odontoideum and transverse lig rupture Method for fixation
Number of patients
Bone-chips
O
Stainless steel wire + bone-chips Stainless steel wire + bone-chips + methyl-methacrylate
8 2
in three patients Two of these were painfree after the operation and the third had less pain. Five patients were fixed with stainless steel wire and bonechips and all were healed on radiologic examination and clinically classified as good. Fourteen patients were fixed with stainless steel wire, bonechips, and methyl methacrylate Thirteen patients were healed with stability on radiologic examination Thirteen were clinically good and one fair This patient had some suboccipital pain One patient had a movement from 3 mm to 6 mm on flexion-extension on the radiograph but he was clinically classified as good as he did not any longer have any symptoms from the cervical spine. Other Conditions (Table 2) Eight patients were fixed with stainless steel wire and bonechips No patient showed any mobility on radiology examination One of these patients was clinically classified as fair He was troubled by some pain and tiredness after a day's work. Two patients were fixed with stainless steel wire, bone-chips and methyl-methacrylate Both were stable on radiologic examination One patient was clinically classified as good and one as fair The last one had a tetraparesis and was unable to walk He had regained some strength and could walk with a support.
Discussion In the present investigation the indication for fusion of atlanto-axial dislocation was primarily when incapacitating pain was present and this could be related to a dislocation with pathological atlanto-axial separation or protrusion of the odontoid process into the skull In patients with neurologic symptoms the indication for
Radiologic examination in flexion and extension
Clinical results
No mobility Mobility healed not healed
Good
8 2
7 I
Fair
1 I
fusion further justified the procedure The aim of the operative procedure is to relieve pain and also to furnish the atlanto-axial joint with a reliable stability. Our intention has been to achieve this by as simple a method as possible, which should also permit early postoperative mobilization Wiring has been suggested to include the occiput, atlas, and axis for stability, but in order to simplify the procedure we have excluded the occiput in cases wiht anterior atlanto-axial dislocation This simplification need not necessarily imply a decrease in the stability as the wire loop running over (posterior) to the transversely placed Rush-pin in the spinous process of the axis will pull the atlas in a posterior direction and bring it in close contact with the odontoid process With the other loop of the wire being crossed downwards to the base of the spinous process of the axis the posterior arch of the atlas will be brought nearer the axis which will further increase the stability of the two vertebrae This hypothesis is at present the object of further study including a series of experiments in which the stability of the fixation is tested In five of the rheumatoid patients we did not succeed in applying the methyl methacrylate satisfactorily or found it superfluous as the stability achieved by the wires was judged reliable No disadvantages were observed and good healing was attained in all these cases. In the radiologic part of this investigation it became evident that reliable stability was achieved in 18 of 19 fusions in rheumatoid patients On analysis of the patients in whom satisfactory stability was not
248
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
achieved we found that the wire had not been pulled well enough Stability is, however, further increased by the addition of methyl-methacrylate which renders such good stability that postoperative mobilization can be instituted almost the day after the operation.
For long-time fixation and stability it is assumed that the bone-chips will form a bone block which can be demonstrated at later radiography In some cases in this material it was impossible due to the bad quality of bone to pass a wire around the atlas and instead bone only was applied This 'necessitated external fixation postoperatively but did not limit the mobilization of the patient. The procedure carried out in fixation of inferior atlanto-axial dislocation gives stability as the position of the bone block acts as a stopper against further downward migration In addition of course the cement renders stability Our experience is at present limited to three patients only and it is planned to further test the reliability of this method. References Bland, J H , Davis, P H , Conlon, M G , Van Buskirk, F W , Duart, C G : Rheumatoid arthritis of cervical spine Arch. intern Med 112, 892-898 (1963) Brattstr 6m, H , Granholm, L : Atlanto-axial fusion in rheumatoid arthritis Acta orthop scand 47, 619-628 (1976) Brooks, A , Jenkins, E B : Atlanto-axial arthrodesis by the wedge compression method J Bone Jt Surg 60-A, 279284 (1978)
Cibert, M , Vignon, G , Chapuy, P : La luxation atloidoaxoidienne au cours de la polyarthrite de l'adulte A propos de 27 cas, dont 7 oprs de greffe cervicale post 6rieure Rev. Lyon Med 19, 77-92 (1970) Davis, F W , Markley, M E : Rheumatoid arthritis with death from medullary compression Ann intern Med 35, 451454 (1951) Dirheimer, Y : The cranio-vertebral region in chronic inflammatory rheumatic diseases Berlin-Heidelberg-New York: Springer 1977 Gallie, W E : Fractures and dislocations of the cervical spine. Amer J Surg 46, 495-506 (1939) Martel, W , Abell, M R : Fatal atlanto-axial luxation in rheumatoid arthritis Arthr Rheum 6, 224-231 (1963) Martel, W , Page, J W : Cervical vertebral erosion and subluxation in rheumatoid arthritis and ankylosing spondylitis. Arthr Rheum 3, 546-556 (1960) Mathews, J A : Atlanto-axial subluxation in rheumatoid arthritis Ann rheum Dis 28, 260-266 (1969) Rana, N A , Taylor, A R : Upward migration of the odontoid peg in rheumatoid arthritis Prov roy Soc Med 64, 717718 (1971) Sharp, J , Purser, D W : Spontaneous atlanto-axial dislocation in ankylosing spondylitis and rheumatoid arthritis Ann. rheum Dis 20, 47-77 (1961) Storey G : Changes on the cervical spine in rheumatoid arthritis with compression of the cord Ann phys Med 4, 216-218 (1958) Webb, F W S , Mickmann, J A , Brew, D S J : Death from vertebral artery thrombosis in rheumatoid arthritis Brit. med J 2, 537-588 (1968)
Received December 27, 1978
Arch Orthop Traumat Surg 93, 243-248 (1979)
©J F Bergmann Verlag 1979
An Alternate Method for Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation Bo Althoff and Ian F Goldie Department of Orthopaedic Surgery, Sahlgren's Hospital, University of G 6teborg, G 6teborg, Sweden
Summary A modification of common methods is described for fixation of anterior and inferior atlantoaxial dislocation (AAD and IAD) In AAD a wire is passed around the atlas arch and knotted around the spinous process of the axis in a way that a figure 8 arrangement is achieved as seen in the lateral view. In IAD a wire is passed through holes in the occiput and knotted around the spinous process of the axis A rectangular bone graft is inserted between the occiput and the spinous process of the axis, thus preventing further inferior dislocation. In both methods methyl methacrylate and bone grafts are as a rule added for further long-time stabilization. The methods have been used in 15 cases of AAD and in three cases of IAD On radiologic examination with attention focused on the immediate postoperative fixation the follow-up time has been three months The long-time results of fixation have been recorded with a follow-up time of six years The fixation proved to be satisfactory in 14 patients with AAD and in the three patients with IAD The clinical results were good in the 14 patients with AAD and in the three with IAD.
A serious complication in cervical involvement in rheumatoid arthritis is a dislocation in the atlantoaxial articulation The atlas can be dislocated anteriorly and with the odontoid process remaining stationary the spinal canal becomes narrowed The function of the spinal cord may be endangered A separation between the atlas and the odontoid process exceeding 3 mm (with further separation in flexion) is regarded as pathological In rheumatoid arthritis this occurs in about 20 % (Sharp and Purser, 1961 ; Martel et al , 1963 ; Cibert, 1969 ; Mathews, 1969 ; Dirheimer, 1977).
A dislocation can also develop vertically with the atlas and occiput descending on the odontoid process which thus passively enters through the foramen occipitale magnum into the skull This occurs in about 7 % (Davies and Markley, 1951 ; Storey, 1952 ; Sharp and Purser, 1961 ; Bland et al , 1963; Martel et al , 1963 ; Webb et al , 1968 ; Mathews, 1969 ; Rana and Taylor, 1971 ; Dirheimer, 1977). When anterior separation over 3 mm is present in the atlanto-axial joint surgical intervention has been suggested in particular if pain and/or neurological symptoms appear related to this region The aim is to stabilize the joint. For treatment of a so-called vertical dislocation, surgical procedures have also been suggested when pain and/or neurological symptoms appear and then it is also aimed at stabilization. Various methods for stabilization have been described, all of which have in common to block the occiput, the atlas, and the axis or the two latter only. Fixation can be achieved by the passage of wires around the skeletal structures with application of bone grafts, and methyl-methacrylate is suggested for further reinforcement. The principles of a stabilizing procedure have been described by Brattstr 6 m and Granholm (1976) who reported on occipito-cervical fusion in 28 patients with rheumatoid arthritis Wires were passed through holes in the occiput and anterior to the posterior arch of the atlas They were knotted over a Rush-pin inserted transversely in the spinous process of the axis For additional stabilization, methyl-methacrylate was placed around the wire over one half of the vertebral arches This rendered a stability permitting early mobilization For a more permanent and biologic fixation bone grafts were placed over the roughened 0344-8444/79/0093/0243/$ 1 20
244
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
surfaces of the other half of the vertebral arches. Excluding the occiput a similar method has been suggested by Gallie ( 1939) and modifications thereof by Brooks ( 1978). The stabilization procedures in vertical dislocation are very much the same as those for the anterior dislocation. In this report we intend to propose a simplified method for fixation which yields satisfactory stabilization and good clinical results The procedures as we have developed them will be described for anterior and vertical (downward) dislocation, respectively Before entering on the description of the methods and their results, definitions of the pathoanatomical conditions will be presented.
Definitions Anterior Atlanto-axial Dislocation (AAD) = anterior (forward) dislocation of the atlas in relation to the odontoid process Separation exceeding 3 mm is regarded as pathological The separation increases on bending the head forwards It is, however, important to measure the distance between the posterior margin of the odontoid process and the anterior border of the posterior arch of the atlas This latter space is subjected to individual variation. Inferior Atlanto-axial Dislocation (IAD) = inferior (downward) dislocation of the atlas on the articular facets of the axis The odontoid process then protrudes through the occipital foramen into the skull The degree of dislocation is measured by the distance between the tip of the odontoid process and a line combining the hard palate with the most caudal point of the occipital curve More than 4 5 mm may be considered pathological (Martel and Page, 1960).
Methods
Fig 1 A Posterior view of the atlas and axis to illustrate the passage of wire for fixation The wire ends are passed on both sides from below anterior to the posterior atlas arch and curved posteriorly in a distal direction A wire loop is formed posterior to a Rush-pin introduced through the spinous process of the axis
Fig 1 B Same as Fig 1 a with wire ends knotted anterior to the Rush-pin and at the base of the spinous process of the axis
For anterior atlanto-axialdislocation the following method has been used The patient has been placed on the operating table in the prone position Traction has not been applied to the cervical column After Lidocaine® injection into the skin to diminsh bleeding a longitudinal incision is made from the 5th cervical spinous process to the occiput The muscles are detached from the spinous processes and vertebral arches The arch of the atlas is carefully dissected taking care not going too laterally for fear
Fig 2 Oblique posterior view of the atlas and the axis The black line on the odontoid process demonstrates fracture line For fixation a wire has been pulled around the arches in a figure of 8 A Rush-pin has been passed through the spinous process of the axis
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
245
Fig 3 A Radiograph of flexion in cervical spine with anterior dislocation of the atlanto-axial joint in rheumatoid arthritis B Wire in figure of 8 fixation of dislocation illustrated in Fig 3 A. Atlanto-axial reduction has been obtained with the atlas pressed against the odontoid process The space between the spinous processes is diminished
of injuring the vertebral artery A wire is introduced from below on one side of the midline in front of the posterior arch of the atlas It is then pulled through the atlanto-occipital space The other end of the wire is proceeded with in the same way on the opposite side A loop has now been formed of the wire in a distal direction and this loop is passed over (posterior to) a Rush-pin of 3 cm which has been drilled transversely through the posterior part of the spinous process of the axis (Figs 1 a, b). The free ends of the wire are knotted at the base of the spinous
process of the axis and thus a loop of 8 has been accomplished (Fig 2) Before knotting the wire ends the atlas is pulled posteriorly for stabilization against the odontoid process (Figs. 3 a, b) In cases where the bone is brittle and does not permit pulling of the wire this can be retained without pull and then act as a stabilizer for the cement If the atlas cannot resist the pull of the wire, bone only can be transplanted and external fixation applied In most cases, however, the wire can be applied as described and once this has been achieved methyl methacrylate
Fig 4 A-D A Lateral radiograph of inferior atlanto-axial dislocation B Lateral tomogram of the atlas and the axis indicating degree of inferior atlanto-axial dislocation in Fig 4 A. C Radiograph of fixation of inferior atlanto-axial dislocation with wire through holes in the occiput and knotted over a Rush-pin introduced through the spinous process of the axis Asterisk indicates the corticocancellous bone graft which blocks further inferior dislocation. D Oblique view of 4 C
246
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
Material Since 1972 thirty-three patients have been treated surgically for atlanto-axial dislocation Twenty-three of these suffered from classical rheumatoid arthritis and ten from other conditions. These conditions consisted of one acute fracture of the odontoid process, five non-united fractures of the odontoid process, four os odontoideum and one patient with rupture or elongation of the transverse ligament.
Rheumatoid Arthritis (n = 23)
Fig 4E Posterior view of the occiput, the atlas, and the axis A bone block has been interposed between the occiput and the spinous process of the axis and secured by a steelwire over a Rush-pin
is placed from the occiput down over the spinous processes to the axis and also moulded into the wires for better stabilization not only in flexion-extension but also in rotation The cortical surfaces of the occiput, the atlas, the axis, the third, and at times also the fourth vertebra are roughened with a dentist's drill. Cancellous bone from the iliac bone is then placed over these rough areas two drainages are introduced and the suturing is done in layers Postoperatively, the patient receives a soft collar for a week or two (in cases without wires: hard collar for three months) The patient is mobilized the day after the operation. Inferior atlanto-axial dislocation is treated surgically with the patient placed on the operating table in the prone position and the procedure is carried out in the same way as is described above The fixation is done as follows Two holes are drilled through the occiput one on each side of the midline about 1 cm from the posterior border of the occipital foramen This should not cause any conflict with the transverse sinus The posterior arches are prepared as described above A block of bone in the form of a rectangle is taken from the iliac bone One of the short sides is placed against the occiput anterior to the drilled holes. The opposite short side is cut out in its middle so that the block can be pressed down over the atlas and axis arches with the spinous process of the axis penetrating through the prepared slit in the bone block The block thus achieves an appearance like a pair of trousers with each trouser leg on either side of the spinous process A wire is now introduced through the holes of the occiput and pulled down and knotted over a Rush-pin around the spinous process of the axis posterior to the bone block which thus becomes pressed against the arches of the vertebrae (Figs 4 a-d) The cancellous side of the bone block rests against the arches Cement is applied over the midline involving the wire for immediate and stable fixation Cancellous bone chips are further placed around the bone block on the previously roughened posterior surfaces of the arches Two drainages are applied and suturing is carried out in layers Also in these cases a soft collar is given for 1-2 weeks and mobilization starts on the day after operation.
Preoperative radiologic examination showed dislocation of the atlas in all 23 cases The dislocation was between 5 mm and 17 mm In addition, three patients had an inferior dislocation. Eight were men and 15 were women The age at operation was between 36 and 73 years with a median age of 56 years All patients had severe occipital pain and 17 had signs which could be ascribed to spinal cord compression In 20 patients the fusion involved only the atlas and the axis In three additional cases the occiput was involved. Other Conditions (n = 10) The age at operation of these patients was between 15 and 73 years with a median age of 37 years Seven were men and three were women Eight patients had signs of spinal cord compression One patient with an os odontoideum had after a traffic accident long-lasting cervical pain and mobility between his os odontoideum and axis The last patient was an acute odontoid fracture which was unstable In nine patients a fusion between the atlas and the axis was performed In one additional patient with an os odontoideum the occiput was involved In this patient the posterior arch of the atlas had been removed 17 years earlier.
Follow-Up All 33 patients were examined clinically and radiographs were taken in flexion and extension of the cervical spine at least three months after the operation This was done in an attempt to analyze the efficacy of the stabilizing procedure on a short-time basis Twenty-three patients were followed and reexamined for one year or more after the operation Six patients had died at the time of follow-up No death had any relation to the operation or to the disease in the upper cervical spine The causes of death were renal failure in three patients, cardiac infarction in one, cerebral hemorrhage in one and a metastatic carcinoma from the kidney in one patient. Definition of ClinicalResults Good: free of pain and preoperative neurologic deficit eliminated or much reduced. Fair : less pain Preoperative neurologic deficit partly reduced. Rheumatoid Arthritis (Table 1) Four patients were operated by putting in bone-chips only as the atlas could not resist the pull of the wire One was healed satisfactorily as judged by the radiographs There was mobility
247
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation Table 1 Radiologic and clinical results of different methods of fixation in atlanto-axial dislocation in rheumatoid arthritis Method for fixation
Number of patients
Radiologic examination in flexion and extension
Clinical results
No mobility Mobility healed not healed
Good
Bone-chips
4
1
Stainless steel wire + bone-chips
5
5
14
13
Stainless steel wire + bone-chips + methyl-methacrylate
3
3 5
1
Fair
13
1 -
1
Table 2 Radiologic and clinical results of different methods of fixation in odontoid fracture, os odontoideum and transverse lig rupture Method for fixation
Number of patients
Bone-chips
O
Stainless steel wire + bone-chips Stainless steel wire + bone-chips + methyl-methacrylate
8 2
in three patients Two of these were painfree after the operation and the third had less pain. Five patients were fixed with stainless steel wire and bonechips and all were healed on radiologic examination and clinically classified as good. Fourteen patients were fixed with stainless steel wire, bonechips, and methyl methacrylate Thirteen patients were healed with stability on radiologic examination Thirteen were clinically good and one fair This patient had some suboccipital pain One patient had a movement from 3 mm to 6 mm on flexion-extension on the radiograph but he was clinically classified as good as he did not any longer have any symptoms from the cervical spine. Other Conditions (Table 2) Eight patients were fixed with stainless steel wire and bonechips No patient showed any mobility on radiology examination One of these patients was clinically classified as fair He was troubled by some pain and tiredness after a day's work. Two patients were fixed with stainless steel wire, bone-chips and methyl-methacrylate Both were stable on radiologic examination One patient was clinically classified as good and one as fair The last one had a tetraparesis and was unable to walk He had regained some strength and could walk with a support.
Discussion In the present investigation the indication for fusion of atlanto-axial dislocation was primarily when incapacitating pain was present and this could be related to a dislocation with pathological atlanto-axial separation or protrusion of the odontoid process into the skull In patients with neurologic symptoms the indication for
Radiologic examination in flexion and extension
Clinical results
No mobility Mobility healed not healed
Good
8 2
7 I
Fair
1 I
fusion further justified the procedure The aim of the operative procedure is to relieve pain and also to furnish the atlanto-axial joint with a reliable stability. Our intention has been to achieve this by as simple a method as possible, which should also permit early postoperative mobilization Wiring has been suggested to include the occiput, atlas, and axis for stability, but in order to simplify the procedure we have excluded the occiput in cases wiht anterior atlanto-axial dislocation This simplification need not necessarily imply a decrease in the stability as the wire loop running over (posterior) to the transversely placed Rush-pin in the spinous process of the axis will pull the atlas in a posterior direction and bring it in close contact with the odontoid process With the other loop of the wire being crossed downwards to the base of the spinous process of the axis the posterior arch of the atlas will be brought nearer the axis which will further increase the stability of the two vertebrae This hypothesis is at present the object of further study including a series of experiments in which the stability of the fixation is tested In five of the rheumatoid patients we did not succeed in applying the methyl methacrylate satisfactorily or found it superfluous as the stability achieved by the wires was judged reliable No disadvantages were observed and good healing was attained in all these cases. In the radiologic part of this investigation it became evident that reliable stability was achieved in 18 of 19 fusions in rheumatoid patients On analysis of the patients in whom satisfactory stability was not
248
B Althoff and I F Goldie: Posterior Fixation in Anterior and Inferior Atlanto-Axial Dislocation
achieved we found that the wire had not been pulled well enough Stability is, however, further increased by the addition of methyl-methacrylate which renders such good stability that postoperative mobilization can be instituted almost the day after the operation.
For long-time fixation and stability it is assumed that the bone-chips will form a bone block which can be demonstrated at later radiography In some cases in this material it was impossible due to the bad quality of bone to pass a wire around the atlas and instead bone only was applied This 'necessitated external fixation postoperatively but did not limit the mobilization of the patient. The procedure carried out in fixation of inferior atlanto-axial dislocation gives stability as the position of the bone block acts as a stopper against further downward migration In addition of course the cement renders stability Our experience is at present limited to three patients only and it is planned to further test the reliability of this method. References Bland, J H , Davis, P H , Conlon, M G , Van Buskirk, F W , Duart, C G : Rheumatoid arthritis of cervical spine Arch. intern Med 112, 892-898 (1963) Brattstr 6m, H , Granholm, L : Atlanto-axial fusion in rheumatoid arthritis Acta orthop scand 47, 619-628 (1976) Brooks, A , Jenkins, E B : Atlanto-axial arthrodesis by the wedge compression method J Bone Jt Surg 60-A, 279284 (1978)
Cibert, M , Vignon, G , Chapuy, P : La luxation atloidoaxoidienne au cours de la polyarthrite de l'adulte A propos de 27 cas, dont 7 oprs de greffe cervicale post 6rieure Rev. Lyon Med 19, 77-92 (1970) Davis, F W , Markley, M E : Rheumatoid arthritis with death from medullary compression Ann intern Med 35, 451454 (1951) Dirheimer, Y : The cranio-vertebral region in chronic inflammatory rheumatic diseases Berlin-Heidelberg-New York: Springer 1977 Gallie, W E : Fractures and dislocations of the cervical spine. Amer J Surg 46, 495-506 (1939) Martel, W , Abell, M R : Fatal atlanto-axial luxation in rheumatoid arthritis Arthr Rheum 6, 224-231 (1963) Martel, W , Page, J W : Cervical vertebral erosion and subluxation in rheumatoid arthritis and ankylosing spondylitis. Arthr Rheum 3, 546-556 (1960) Mathews, J A : Atlanto-axial subluxation in rheumatoid arthritis Ann rheum Dis 28, 260-266 (1969) Rana, N A , Taylor, A R : Upward migration of the odontoid peg in rheumatoid arthritis Prov roy Soc Med 64, 717718 (1971) Sharp, J , Purser, D W : Spontaneous atlanto-axial dislocation in ankylosing spondylitis and rheumatoid arthritis Ann. rheum Dis 20, 47-77 (1961) Storey G : Changes on the cervical spine in rheumatoid arthritis with compression of the cord Ann phys Med 4, 216-218 (1958) Webb, F W S , Mickmann, J A , Brew, D S J : Death from vertebral artery thrombosis in rheumatoid arthritis Brit. med J 2, 537-588 (1968)
Received December 27, 1978
