FRACTURE O F ODONTOID PROCESS
hip in children in the Auckland area over a period of 23 years, whereas in 1967 a total of only 266 cases had been reported in the world literature.
CONCLUSIONS As with other surveys, factors predisposing to a relatively unsatisfactory result were the severity of the trauma, the presence of associated fractures about the involved hip joint, delay in treatment and the age of the patient. The type of non-operative treatment did not seem to be a factor. This study supports the view that the hip joint of a child becomes dislocated more readily than that of an adult, as 60% of the injuries were due to relatively minor trauma and there was found to be a low incidence of associated fractures.
MARAR A N D TAY
ACKNOWLEDGEMENTS W e wish to thank the orthopzdic surgeons on the staff of the Middlemore Hospital for permission to study their patients and the staff members of the Photographic Department for their photographic reproductions.
REFERENCES BERNHANG, A. M. (1972). J. Bone Jt Surg., 5 2 ~ : 365. FUNSTEN, R. V., KINSER,P. and FRAENKEL, C. J. (1938), J. Bone Jt Surg., 2 0 : 124. F U N K , F. J., JR (1g6z), I . Bone J t Surg., m: 113. GLASS.A. and POWELL, H. D. W. (1961), J. Bone Jt surg., 4313:zg. MORTON,K. S. (1954)~Brit. J. Surg., 47: 233. PENNSYLVANIAORTHOPEDICSOCIETY : GARTLAND, J. J. (Chairman), Initial report (1g60), J . Bone J t Surg., +:705. PENNSYLVANIA ORTHOPEDIC SOCIETY ( 1967)~ Final report, I. Bone Jt Surg., ~ O A : 79.
FRACTURE OF THE ODONTOID PROCESS B. C. M A R A RAND ~ C. K. TAY D e p a r t m e n t of O r t h o p e d i c Surgery, U n i v e r s i t y of Singapore A review of 26 cases of odontoid fractures has been carried out. Late diagnosis and consequent delay in treatment were found to be important causes of non-union. Myelopathy in odontoid fractures is of two types. One type is that present immediately after injury, while the other is delayed. In treatment of long-standing cases, only fusion without posterior decompression should be done. I f the latter procedure is carried out, it can produce medullospinal hrematomyelia with respiratory arrest and tetraplegia. I n the performance of atlanto-axial fusion, the technique of bone grafting and the use of thick w k e s need em) hasis.
FRACTUREof the odontoid process has always attracted interest because of the high rate of non-union and the high mortality in reported series (Osgood and Lund, 1928; Amyes and Anderson, 1956; Alexander e t alii, 1958; Schlesinger and Taveras, 1958; Schatzker et a&, 1971). Mortality rates have been reported as ranging from 5% to 50% Present address : Department of Orthopredics, Rush-Presbyterian-St Luke’s Medical Center, 1753 West Congress Parkway, Chicago, Illinois 60612, U.S.A. Reprints : Dr C. K. Tay, University Department of Orthopaedic Surgery, Singapore General Hospital, Singapore 3, Republic of Singapore. ALIST. N.Z. J. SURG., VOL. 46-NO. 3, AUGUST,1976
(Alexander et dii, 1958). The prevalence of non-union has also remained persistently high. Blockey and Purser (1956) in a review found complete records of 40 cases of odontoid fracture reported in the literature at that time and added 1 1 cases of their own. Schatzker et alii (1971) reported an incidence of nonunion of 63% in their series of 37 cases. More recently, Anderson and D’Alonzo (1g74jnoted that the rate of non-union depended on the site of the fracture and classified these fractures into three types. I n those located high up in the odontoid process (Type I ) and in those low down extending into the body (Type 111), the rate of non-
231
FRACTURE OF ODONTOID PROCESS
union was less than 10%. In those fractures at the junction of the odontoid process and the body (Type 11), they noted a non-union rate of 36%. They attributed this to the fact that Type I1 injuries were basically unstable, and even if initially not displaced they frequently became so later. TABLEI No. of Cases Non-Union
.. Type11 .. Type1
Type111 Total
..
0
..
24
.. ..
2
26
0
-
15 (62.5%) 0
15 (58%)
It was decided to review 26 patients with fractures of the odontoid process seen and treated at the Orthopedic Department of the Singapore General Hospital between January, 1g68 and May, 1975. This Department accepts a large number of patients with cervical spine injuries resulting in either bone or cord damage, the usual number being about 25 annually. The study revealed certain interesting facts about this injury regarding the causes of non-union, myelopathy, and treatment, which up till now have not received sufficient attention in the literature.
FINDINGS AND DISCUSSION There were 22 males and four females. Their ages ranged from nine to 75 years.
MARAR AND TAY
Non- Union Using the classification of Anderson and D’Alonzo (1g74), there were no Type I fractures, 24 Type I1 fractures and 2 Type I11 fractures. Table I shows the relationship between union and the type of fracture. Nonunion was diagnosed when there was no radiological evidence of union ten weeks from the date of injury. I n the present series, those fractures diagnosed a week or later after injury carried a high rate of non-union (Table 2). Of the 26 fractures, 11 were diagnosed later than a week after injury, and of these patients nine (82%) had non-union (Table 2 ) . The two fractures that united were diagnosed eight and ten days respectively from the date of injury. Of the 15 patients whose diagnosis was made at the time of the injury only six (40%) went on to non-union. All the patients with non-union had the Type I1 fracture described by Anderson and D’Alonzo (1974). It appears, therefore, that one of the factors that determines non-union in Type I1 injuries is the time that elapses after the accident before the diagnosis is made. Even those diagnosed at the time of injury in the present series had a 40% rate of non-union in spite of adequate conservative treatment, a figure comparable with the 36% reported by Anderson and D’Alonzo (1974). In addition, these authors also point out that it is the Type I1 fracture that has the highest
I~ICUREI : (left) lateral and (centre) open-mouth views on admission. Note the absence of the normal cervical lordosis. No fracture of the odontoid is visible in these radiographs; (right) same patient, showing lateral view taken four months after injury. Note the forward subluxation of the odontoid. This patient presented with monoparesis. 232
AUST.N.Z. J. SURG., VOL. 46-No.
3, AUGUST, 1976
FRACTURE OF ODONTOID PROCESS
MARAR AND TAY TABLE 2
Summary of the Eleven Patienfs in Whom the Diagnosis was Delayed for More than One Week Serial Our Case Interval between No. Reference Injury and Diaenosis
Odontoid Union following Skull Traction
History and Presenting Symptom
Final Result
I
4
17 days
Did not seek treatment a t time of injury. Monoparesis of upper limb two weeks after injury
United
Remains well six years later. Complete neurological recovery
2
5
8 days
Seen a t timeof injury butdiagnosis delayed. Neck pain with brisk reflexes
United
Remains well six years later
3
7
4
9
2
5
12
15
6
13
________ 7
16
8
19
9
21
I0
22
10months
I
Seen at time of injury in another Skull traction for two weeks prior Successful fusion. Remains well. to occipito-cervical fusion Complete neurological recovery hospital. Presented two months later with monoparesis of upper limb
years
Did not seek treatment a t time of Skull traction for two weeks prior to laminectomy of atlas and injury. Seen by us 15 years later for gradual tetraparesis of decompression of foramen magsix months' duration num
Respiratoryarrest atoperation and tetraplegia noted immediatelv after operation. Died one week later. No autopsy
month
Seen by us one montb after iniury for tetraparesis
Refused any treatment with skull traction, bracing or operation
Did not report for further followup
Seen b y us 10 years after injuky Refused any operative treatment with neck pain and brisk reflexes
Remains the same three years after first being seen in 1972
10 years
months
15 years
2
Successful fusion. Four years after surgery muscle power had improved and reflexes were very brisk
months
__ 4
Did not seek treatment a t time of Skull traction for two weeks prior iyury. Tetraparesis present for to laminectomy of atlas and SIX months. Myelography occipito-cervical fusion showed block at level of atlas
months
Seen a t time of injury. Mono- Skull traction for two weeks Successful fusion. Complete paresis of upper limb developed followed by occipito-cervical neurological recovery one month after injury fusion Seen by us IS years after injury Skull traction for two weeks Successful fusion. Some improvrfor increasing tetraparesis of one followed by occipito-cervical ment in motor power but brisk year's duration fusion reflexes Seen a t time of injury. Had Skull traction applied for 10weeks Atlanto-axial fusion done following persistent neck pain after injury after diagnosis made. No union failure of conservative treatment. Fusion failed and patient refuses furtheroperation. One year later bas very little neck pain with only slight atlanto axial subluxation (Figure 3)
-
I1
24
3 months
Seen a t time of injury. Persistent Skull traction for two weeks Successful fusion followed hy atlanto-axial fusion neck pain after injury
-
rate of non-union and attribute this to the instability of the fracture. Since there were only two patients with Type I11 fractures and no patient with a Type I fracture in the present series, it is difficult to comment on this. I n Table 2, Patients 5 , 7 and 9 illustrate the long-term results of ununited fracture of the odontoid and strongly suggest the importance of operative fusion if comervative treatment fails to produce union.
Diagnosis The high rate of delayed diagnosis in the present series was because six of the 11 patients in whom the diagnosis was made later than a week after the injury did not seek treatment at the time of the accident. Thev came to us at the varying periods shown in Table 2 (Patients I , 3, 5 , 6, 7 and 9 ) . AUST. N.Z. J. SURG., VOL.46-No.
3, AUGUST,1976
They only presented when there was late cord involvement or persistent neck pain. Nevertheless, this still leaves five patients in whom, although they were seen at the time of injury, the diagnosis was not established till a week afterwards. On review of these five patients, it was realized that their initial plain radiographs, consisting of anteroposterior and lateral views, could easily have been passed as normal (Figure I ) . The problem therefore arises as to how to avoid overlooking this injury when the patient is seen at the time of the accident: we now follow the following routine with a suspected cervical spine injury. A high index of suspicion is necessary in all patients with pain in the neck after an accident, especially in the presence of a lateral radiograph which shows absence of the normal cervical lordosis. This absence
233
FRACTURE OF ODONTOID PROCESS of cervical lordosis was present in the lateral radiographs of all the five patients in whom a delayed diagnosis was made, though they were seen a t the time of the injury. A careful neurological examination is very important, a s a few of these patients can have evidence of early cord involvement, such as monoparesis or brisk reflexes with extensor plantar responses. This was found t o be so in some patients earlier in the series who had an odontoid fracture. The pattern of neurological involvement as an aid t o the diagnosis of a cervical spine injury has been noted before (Marar, 1974). If, however, these patients are neurologically normal, we now repeat the plain radiographs one week later, so that the fracture becomes more clearly defined a s in scaphoid fractures. During this period, the patient is given a well-fitting cervical brace that will prevent any flexion or extension of the neck. If these repeat radiographs are normal and the patient still has symptoms, tomograms and stress films of the cervical spine in flexion and extension are done. On these occasions the patient must be postured by the surgeon himself. The patient should state immediately if he feels any numbness or paraesthesia in the limbs during the manceuvre, and the neck should then be brought to the neutral position if this occurs. If these provisions are adhered to the procedure is safe. The author has carried it out on several occasions without any complication developing. Any doubt in the diagnosis will be settled by these special radiographs.
MARAR A N D TAY
ment, the effects of this ranging from very brisk reflexes to tetraparesis. In all these patients there was radiological evidence of atlanto-axial subluxation. This group also improved neurologically with skull traction alone. I n one patient (Number 9, Table z), whose injury had been sustained 15 years previously, the tetraparesis improved, but has not returned to normal even two years after fusion.
TREATMENT
Myelnputlzy in Odontoid Fractures Myelopathv was of two types, which need emphasis. The first was the neurological deficit sustained at the time of injury, while the onset of the second was delayed until w m c weelis, months or even years after the iniurv (Table 2 ) . The latter type was associated with non-union of the odontoid fracture, with atlanto-axial subluxation. Tn the present series, there were five ( 3 3 % ) out of 1 ; patients seen at the time of iniury who showed some degree of cord involvement, ranging from brisk reflexes to monoparesis of an upper limb. However, the iieuroloeical deficit settled in all of them with a few days of treatment in skull traction. I t has been noted previously that any patient with pain in the neck and presenting such neurological signs should alert the physician to the pmsible diagnosis of a hyperextension injurv, such as fracture of the axis arch or a fractured odontoid (Marar, 1974). The second group of patients were those in whom the diagnosis was made later than a week from the date of injury. There were J T such in the present series (Table 2). Out of these, nine (82%) patients (Numbers T to 9 in Table 2 ) had some degree of cord involve-
Here again there are two groups that need consideration. I n the first group, in whom the diagnosis is made at the time of injury, most authorities would agree that if there is still evidence of non-union after 10 to 12 weeks of skull traction, operative treatment consisting of either atlanto-axial fusion or occipito-cervical fusion is indicated. W e use Cone’s callipers, which are simple and easy to apply at the bedside, as the means of skull traction. The Blackburn or Crutch field types are more difficult to apply and cannot be put on at the bedside. Anderson and D’Alonzo (1474) recommend immediate fusion without a trial of skeletal traction in those fractures at the junction of the odontoid process and body of the axis (Type 11). I n our present series, the incidence of non-union in this group is 40%, which fig-ure is approximately the same as theirs. Our policy has been to recommend an initial trial of conservative treatment for ten weeks. This i s followed hv onerative fusion onlv if there i s n o radiolovical evidence of union and atlanto-axial instabilitv is present. In the nresent series there were two Datients in whom conservative treatment resulted in firm fihrous union that is, non-union without atlanto-axial instability (Fig-ure 2 ) . Both natients refused oDerative treatment and remain well even after four years. The two main indications for operative treatment of cervical s h e iniuries are cord comDres+m and instahilitv (Marar. 107
hip in children in the Auckland area over a period of 23 years, whereas in 1967 a total of only 266 cases had been reported in the world literature.
CONCLUSIONS As with other surveys, factors predisposing to a relatively unsatisfactory result were the severity of the trauma, the presence of associated fractures about the involved hip joint, delay in treatment and the age of the patient. The type of non-operative treatment did not seem to be a factor. This study supports the view that the hip joint of a child becomes dislocated more readily than that of an adult, as 60% of the injuries were due to relatively minor trauma and there was found to be a low incidence of associated fractures.
MARAR A N D TAY
ACKNOWLEDGEMENTS W e wish to thank the orthopzdic surgeons on the staff of the Middlemore Hospital for permission to study their patients and the staff members of the Photographic Department for their photographic reproductions.
REFERENCES BERNHANG, A. M. (1972). J. Bone Jt Surg., 5 2 ~ : 365. FUNSTEN, R. V., KINSER,P. and FRAENKEL, C. J. (1938), J. Bone Jt Surg., 2 0 : 124. F U N K , F. J., JR (1g6z), I . Bone J t Surg., m: 113. GLASS.A. and POWELL, H. D. W. (1961), J. Bone Jt surg., 4313:zg. MORTON,K. S. (1954)~Brit. J. Surg., 47: 233. PENNSYLVANIAORTHOPEDICSOCIETY : GARTLAND, J. J. (Chairman), Initial report (1g60), J . Bone J t Surg., +:705. PENNSYLVANIA ORTHOPEDIC SOCIETY ( 1967)~ Final report, I. Bone Jt Surg., ~ O A : 79.
FRACTURE OF THE ODONTOID PROCESS B. C. M A R A RAND ~ C. K. TAY D e p a r t m e n t of O r t h o p e d i c Surgery, U n i v e r s i t y of Singapore A review of 26 cases of odontoid fractures has been carried out. Late diagnosis and consequent delay in treatment were found to be important causes of non-union. Myelopathy in odontoid fractures is of two types. One type is that present immediately after injury, while the other is delayed. In treatment of long-standing cases, only fusion without posterior decompression should be done. I f the latter procedure is carried out, it can produce medullospinal hrematomyelia with respiratory arrest and tetraplegia. I n the performance of atlanto-axial fusion, the technique of bone grafting and the use of thick w k e s need em) hasis.
FRACTUREof the odontoid process has always attracted interest because of the high rate of non-union and the high mortality in reported series (Osgood and Lund, 1928; Amyes and Anderson, 1956; Alexander e t alii, 1958; Schlesinger and Taveras, 1958; Schatzker et a&, 1971). Mortality rates have been reported as ranging from 5% to 50% Present address : Department of Orthopredics, Rush-Presbyterian-St Luke’s Medical Center, 1753 West Congress Parkway, Chicago, Illinois 60612, U.S.A. Reprints : Dr C. K. Tay, University Department of Orthopaedic Surgery, Singapore General Hospital, Singapore 3, Republic of Singapore. ALIST. N.Z. J. SURG., VOL. 46-NO. 3, AUGUST,1976
(Alexander et dii, 1958). The prevalence of non-union has also remained persistently high. Blockey and Purser (1956) in a review found complete records of 40 cases of odontoid fracture reported in the literature at that time and added 1 1 cases of their own. Schatzker et alii (1971) reported an incidence of nonunion of 63% in their series of 37 cases. More recently, Anderson and D’Alonzo (1g74jnoted that the rate of non-union depended on the site of the fracture and classified these fractures into three types. I n those located high up in the odontoid process (Type I ) and in those low down extending into the body (Type 111), the rate of non-
231
FRACTURE OF ODONTOID PROCESS
union was less than 10%. In those fractures at the junction of the odontoid process and the body (Type 11), they noted a non-union rate of 36%. They attributed this to the fact that Type I1 injuries were basically unstable, and even if initially not displaced they frequently became so later. TABLEI No. of Cases Non-Union
.. Type11 .. Type1
Type111 Total
..
0
..
24
.. ..
2
26
0
-
15 (62.5%) 0
15 (58%)
It was decided to review 26 patients with fractures of the odontoid process seen and treated at the Orthopedic Department of the Singapore General Hospital between January, 1g68 and May, 1975. This Department accepts a large number of patients with cervical spine injuries resulting in either bone or cord damage, the usual number being about 25 annually. The study revealed certain interesting facts about this injury regarding the causes of non-union, myelopathy, and treatment, which up till now have not received sufficient attention in the literature.
FINDINGS AND DISCUSSION There were 22 males and four females. Their ages ranged from nine to 75 years.
MARAR AND TAY
Non- Union Using the classification of Anderson and D’Alonzo (1g74), there were no Type I fractures, 24 Type I1 fractures and 2 Type I11 fractures. Table I shows the relationship between union and the type of fracture. Nonunion was diagnosed when there was no radiological evidence of union ten weeks from the date of injury. I n the present series, those fractures diagnosed a week or later after injury carried a high rate of non-union (Table 2). Of the 26 fractures, 11 were diagnosed later than a week after injury, and of these patients nine (82%) had non-union (Table 2 ) . The two fractures that united were diagnosed eight and ten days respectively from the date of injury. Of the 15 patients whose diagnosis was made at the time of the injury only six (40%) went on to non-union. All the patients with non-union had the Type I1 fracture described by Anderson and D’Alonzo (1974). It appears, therefore, that one of the factors that determines non-union in Type I1 injuries is the time that elapses after the accident before the diagnosis is made. Even those diagnosed at the time of injury in the present series had a 40% rate of non-union in spite of adequate conservative treatment, a figure comparable with the 36% reported by Anderson and D’Alonzo (1974). In addition, these authors also point out that it is the Type I1 fracture that has the highest
I~ICUREI : (left) lateral and (centre) open-mouth views on admission. Note the absence of the normal cervical lordosis. No fracture of the odontoid is visible in these radiographs; (right) same patient, showing lateral view taken four months after injury. Note the forward subluxation of the odontoid. This patient presented with monoparesis. 232
AUST.N.Z. J. SURG., VOL. 46-No.
3, AUGUST, 1976
FRACTURE OF ODONTOID PROCESS
MARAR AND TAY TABLE 2
Summary of the Eleven Patienfs in Whom the Diagnosis was Delayed for More than One Week Serial Our Case Interval between No. Reference Injury and Diaenosis
Odontoid Union following Skull Traction
History and Presenting Symptom
Final Result
I
4
17 days
Did not seek treatment a t time of injury. Monoparesis of upper limb two weeks after injury
United
Remains well six years later. Complete neurological recovery
2
5
8 days
Seen a t timeof injury butdiagnosis delayed. Neck pain with brisk reflexes
United
Remains well six years later
3
7
4
9
2
5
12
15
6
13
________ 7
16
8
19
9
21
I0
22
10months
I
Seen at time of injury in another Skull traction for two weeks prior Successful fusion. Remains well. to occipito-cervical fusion Complete neurological recovery hospital. Presented two months later with monoparesis of upper limb
years
Did not seek treatment a t time of Skull traction for two weeks prior to laminectomy of atlas and injury. Seen by us 15 years later for gradual tetraparesis of decompression of foramen magsix months' duration num
Respiratoryarrest atoperation and tetraplegia noted immediatelv after operation. Died one week later. No autopsy
month
Seen by us one montb after iniury for tetraparesis
Refused any treatment with skull traction, bracing or operation
Did not report for further followup
Seen b y us 10 years after injuky Refused any operative treatment with neck pain and brisk reflexes
Remains the same three years after first being seen in 1972
10 years
months
15 years
2
Successful fusion. Four years after surgery muscle power had improved and reflexes were very brisk
months
__ 4
Did not seek treatment a t time of Skull traction for two weeks prior iyury. Tetraparesis present for to laminectomy of atlas and SIX months. Myelography occipito-cervical fusion showed block at level of atlas
months
Seen a t time of injury. Mono- Skull traction for two weeks Successful fusion. Complete paresis of upper limb developed followed by occipito-cervical neurological recovery one month after injury fusion Seen by us IS years after injury Skull traction for two weeks Successful fusion. Some improvrfor increasing tetraparesis of one followed by occipito-cervical ment in motor power but brisk year's duration fusion reflexes Seen a t time of injury. Had Skull traction applied for 10weeks Atlanto-axial fusion done following persistent neck pain after injury after diagnosis made. No union failure of conservative treatment. Fusion failed and patient refuses furtheroperation. One year later bas very little neck pain with only slight atlanto axial subluxation (Figure 3)
-
I1
24
3 months
Seen a t time of injury. Persistent Skull traction for two weeks Successful fusion followed hy atlanto-axial fusion neck pain after injury
-
rate of non-union and attribute this to the instability of the fracture. Since there were only two patients with Type I11 fractures and no patient with a Type I fracture in the present series, it is difficult to comment on this. I n Table 2, Patients 5 , 7 and 9 illustrate the long-term results of ununited fracture of the odontoid and strongly suggest the importance of operative fusion if comervative treatment fails to produce union.
Diagnosis The high rate of delayed diagnosis in the present series was because six of the 11 patients in whom the diagnosis was made later than a week after the injury did not seek treatment at the time of the accident. Thev came to us at the varying periods shown in Table 2 (Patients I , 3, 5 , 6, 7 and 9 ) . AUST. N.Z. J. SURG., VOL.46-No.
3, AUGUST,1976
They only presented when there was late cord involvement or persistent neck pain. Nevertheless, this still leaves five patients in whom, although they were seen at the time of injury, the diagnosis was not established till a week afterwards. On review of these five patients, it was realized that their initial plain radiographs, consisting of anteroposterior and lateral views, could easily have been passed as normal (Figure I ) . The problem therefore arises as to how to avoid overlooking this injury when the patient is seen at the time of the accident: we now follow the following routine with a suspected cervical spine injury. A high index of suspicion is necessary in all patients with pain in the neck after an accident, especially in the presence of a lateral radiograph which shows absence of the normal cervical lordosis. This absence
233
FRACTURE OF ODONTOID PROCESS of cervical lordosis was present in the lateral radiographs of all the five patients in whom a delayed diagnosis was made, though they were seen a t the time of the injury. A careful neurological examination is very important, a s a few of these patients can have evidence of early cord involvement, such as monoparesis or brisk reflexes with extensor plantar responses. This was found t o be so in some patients earlier in the series who had an odontoid fracture. The pattern of neurological involvement as an aid t o the diagnosis of a cervical spine injury has been noted before (Marar, 1974). If, however, these patients are neurologically normal, we now repeat the plain radiographs one week later, so that the fracture becomes more clearly defined a s in scaphoid fractures. During this period, the patient is given a well-fitting cervical brace that will prevent any flexion or extension of the neck. If these repeat radiographs are normal and the patient still has symptoms, tomograms and stress films of the cervical spine in flexion and extension are done. On these occasions the patient must be postured by the surgeon himself. The patient should state immediately if he feels any numbness or paraesthesia in the limbs during the manceuvre, and the neck should then be brought to the neutral position if this occurs. If these provisions are adhered to the procedure is safe. The author has carried it out on several occasions without any complication developing. Any doubt in the diagnosis will be settled by these special radiographs.
MARAR A N D TAY
ment, the effects of this ranging from very brisk reflexes to tetraparesis. In all these patients there was radiological evidence of atlanto-axial subluxation. This group also improved neurologically with skull traction alone. I n one patient (Number 9, Table z), whose injury had been sustained 15 years previously, the tetraparesis improved, but has not returned to normal even two years after fusion.
TREATMENT
Myelnputlzy in Odontoid Fractures Myelopathv was of two types, which need emphasis. The first was the neurological deficit sustained at the time of injury, while the onset of the second was delayed until w m c weelis, months or even years after the iniurv (Table 2 ) . The latter type was associated with non-union of the odontoid fracture, with atlanto-axial subluxation. Tn the present series, there were five ( 3 3 % ) out of 1 ; patients seen at the time of iniury who showed some degree of cord involvement, ranging from brisk reflexes to monoparesis of an upper limb. However, the iieuroloeical deficit settled in all of them with a few days of treatment in skull traction. I t has been noted previously that any patient with pain in the neck and presenting such neurological signs should alert the physician to the pmsible diagnosis of a hyperextension injurv, such as fracture of the axis arch or a fractured odontoid (Marar, 1974). The second group of patients were those in whom the diagnosis was made later than a week from the date of injury. There were J T such in the present series (Table 2). Out of these, nine (82%) patients (Numbers T to 9 in Table 2 ) had some degree of cord involve-
Here again there are two groups that need consideration. I n the first group, in whom the diagnosis is made at the time of injury, most authorities would agree that if there is still evidence of non-union after 10 to 12 weeks of skull traction, operative treatment consisting of either atlanto-axial fusion or occipito-cervical fusion is indicated. W e use Cone’s callipers, which are simple and easy to apply at the bedside, as the means of skull traction. The Blackburn or Crutch field types are more difficult to apply and cannot be put on at the bedside. Anderson and D’Alonzo (1474) recommend immediate fusion without a trial of skeletal traction in those fractures at the junction of the odontoid process and body of the axis (Type 11). I n our present series, the incidence of non-union in this group is 40%, which fig-ure is approximately the same as theirs. Our policy has been to recommend an initial trial of conservative treatment for ten weeks. This i s followed hv onerative fusion onlv if there i s n o radiolovical evidence of union and atlanto-axial instabilitv is present. In the nresent series there were two Datients in whom conservative treatment resulted in firm fihrous union that is, non-union without atlanto-axial instability (Fig-ure 2 ) . Both natients refused oDerative treatment and remain well even after four years. The two main indications for operative treatment of cervical s h e iniuries are cord comDres+m and instahilitv (Marar. 107
