Treatment of Type II axis fractures is controversial, and different conservative and surgical options exist. Important features that influence bony fusion in odontoid fractures treated with all external immobilization devices are a delayed presentation, a dislocation of the fragment of more than 6 mm, age older than 65 years, and the comminution of the base of the dens (Hadley IIa) (11,19,21,23,30). Hanigan et al. (25) documented a fusion rate of 50% in a series of patients age 80 years or older with odontoid Type II axis fractures that were treated conservatively. Lennarson et al. (33) concluded that patients over the age of 50 years had a 21 times greater chance of nonunion of acute odontoid fractures treated with immobilization than with surgery. Moreover, the use of halo devices has even been related to complications such as pin loosening, pin site infections, cerebrospinal fluid leakage from the pinhole, and brain abscess (14,16–18,28).
Recently, in the literature, attention has been paid to the complications of the halo vest in elderly patients, and it has been emphasized that the device is not well tolerated by all patients. Patients older than age 65 years who are treated with a halo device have a high risk for the development of pneumonia and acute cardiac or respiratory failure (35,40,44). Various investigators have suggested posterior fusion for elderly patients (3,31). Pepin et al. (40) suggested a posterior C1–C2 fusion for patients older than 75 years of age because of their intolerance of the halo vest. Conversely, other authors have proposed an anterior approach with screw fixation even for the elderly population (6,7,26).
Anterior screw fixation provides the most anatomic and functional result for odontoid fractures (32). Our fusion rate in elderly patients compares well with reported anterior screw odontoid fixation rates, ranging from 75 to 96% in patients of all ages who have undergone early fixation (15,43). The good rate we achieved in elderly patients is in line with the study by Börm et al. (7), who reported solid bony fusion in 75% of patients older than 70 years whose odontoid fractures were treated with early anterior screw fixation; they concluded that outcome is not influenced by age. In elderly patients who present with minimal symptoms or are asymptomatic, this surgical technique offers acceptable fracture healing and an uncomplicated postoperative course. Only 1 patient in our series presented with myelopathy, which responded to halo traction. In contrast to our study, Kirankumar et al. (29) reported that several patients in their series with Anderson Type II fractures presented with late compressive myelopathy and underwent anterior decompression.
Another important factor that almost certainly influences fusion rates and hence the decision on which management option to choose is the time elapsing after the trauma. Because all the patients whose records we reviewed presented for delayed treatment of odontoid fractures more than 6 to 12 months after the causative traumatic event, we cannot compare their outcomes with those of patients in other reported series, such as that of Apfelbaum et al. (5), whose patients underwent early treatment or delayed treatment more than 18 months after trauma. In their series, anterior screw fixation in 18 patients with axis fractures treated more than 18 months after injury resulted in a nonfusion rate of 31% (5). Stressing this poor result, they suggested anterior screw fixation for patients with fractures within 6 months after trauma and posterior C1–C2 fusion for fractures discovered more than 18 months after injury (5). In 80% of their patients, the authors inserted 2 screws (5). A technical point is the use of a single screw or 2 screws for odontoid fixation procedures. Especially in long-standing fractures, whose fracture edges tend to become sclerotic on the side of the fracture line, we suppose that a single screw probably ensures a larger surface for fusion between fragments. Two screws do not necessarily ensure a higher rate of fusion (27,42). In a series of 42 patients (20 treated with the 1-screw and 22 with the 2-screw procedure), Jenkins et al. (27) reported similar bone fusion rates in the 2 groups (81 versus 85%). Because their series included patients with recent odontoid fractures, whether a single screw ensures a higher rate of bone fusion in patients undergoing late treatment remains open to question.
In contrast to other series, none of our patients presented with fixed atlantoaxial anterolisthesis or retrolisthesis, and preoperative traction alignment under radiological control was successful in all patients in whom we used it (9). Even in the patient whose fracture had a slight anterior oblique rime and a large displacement (Fig. 7), we realigned the dens with halo traction. Although the patient's neurological status improved during the postoperative course, the postoperative radiographic studies showed residual atlantoaxial dislocation (Fig. 3). This finding prompted us to propose posterior fusion surgery, but the patient refused and was discharged wearing a Philadelphia collar. A late CT follow-up scan at 16 months showed bone union with partial bone remodeling (Fig. 4), and the patient remained free of neurological symptoms.
In 2 (22.2%) of the 9 patients in this series, anterior screw fixation failed to achieve bone fusion. In 1 patient with minor odontoid displacement, preoperative and postoperative imaging showed evident fragment diastasis (Figs. 2 and 5). In these cases, the fixation may fail because the odontoid screw leaves a gap between the fragments (Fig. 5) that may cause the C2 vertebral body to fracture during neck flexion-extension (13). We think this risk could be eliminated by using posterior C1–C2 fixation to limit neck flexion-extension. In the other patient in whom postoperative assessment showed no bone fusion, follow-up imaging at 8 months (Fig. 6) and 14 months showed fibrous union that appeared stable on dynamic CT scan reconstructions. We suggest that, in elderly patients, a fibrous union with no signs of instability, no residual listhesis, and an anatomic dens alignment should be considered a satisfactory outcome, although a definitive conclusion awaits data from further research.
The patients in this series who presented for delayed treatment of odontoid fractures were selected to undergo anterior fixation according to the currently accepted criteria. The major recognized anatomic contraindications include a comminuted fracture at the base of the dens that makes it impossible to compress the fragments and a disrupted transverse ligament (10,20). Even though a fracture line oriented in a cranial-posterior to caudal-anterior direction may lead to incorrect alignment, we used this management option in 1 patient and resorted to a nonanatomic bone fusion (Fig. 4), although the patient had a successful neurological outcome (5). Finally, some deem a transverse dens diameter of 9 mm as critical for the placement of a 3.5-mm odontoid screw (38). Although osteoporosis is generally listed among factors influencing bone fusion, precisely how osteoporosis should be graded remains unclear (26,37). No patients in our series had marked or severe radiological signs of osteoporosis on x-rays, but we did not determine the possible correlation of this feature to the time elapsing between trauma and the overall time needed for bone fusion. Another imperative preoperative task, especially in elderly patients, is that of quantifying the anesthesiological risk. This caveat notwithstanding, patients presenting for delayed nonemergency treatment of an odontoid fracture generally have no acute anesthesiological contraindications to a neurosurgical intervention.
Anterior screw fixation is an appropriate operative treatment for Anderson Type II dens fractures if patients fulfill all of the current criteria. Our preliminary data suggest that the technique appears feasible for managing remote axis fractures within 12 months after the trauma, seems safe in the elderly, and offers acceptable fracture healing.
Further studies are needed to investigate whether factors such as the orientation of the fracture line, the reducibility of the fracture, the preoperative myelopathy, the use of 1 or 2 screws, and osteoporosis influence the outcome. An anterior oblique fracture line does not necessarily contraindicate anterior screw odontoid fixation if the dens can be realigned, but nonanatomic bone fusion may occur. Lag screw compression appears fundamental in favoring bone fusion, insofar as nonfusion and instability may be related to persistent fragment diastases. Preoperative assessment must include a careful evaluation of the anesthesiological risks. A long radiological follow-up is indicated to make sure that the dens remains properly aligned and to document late ossification.
The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article.
2. Anderson LD, D'Alonzo RT: Fractures of the odontoid process of the axis. J Bone Joint Surg Am
3. Andersson S, Rodrigues M, Olerud C: Odontoid fractures: High complication rates associated with anterior screw fixation in the elderly. Eur Spine J
3a. Anonymous: Isolated fractures of the axis in adults, in Guidelines for management of acute cervical spine injuries. Neurosurgery 50 [Suppl]:S125–S139, 2002.
4. Apfelbaum RI: Anterior screw fixation of odontoid fractures, in Rengachary SS, Wilkins RH (eds): Neurosurgical Operative Atlas
. Baltimore, Williams & Wilkins, 1992, pp 189–199.
5. Apfelbaum RI, Lonser RR, Veres R, Casey A: Direct anterior screw fixation for recent and remote odontoid fractures. J Neurosurg
6. Berlemann U, Schwarzenbach O: Dens fractures in the elderly. Results of anterior screw fixation in 19 elderly patients. Acta Orthop Scand
7. Börm W, Kast E, Richter HP, Mohr K: Anterior screw fixation in type II odontoid fractures: Is there a difference in outcome between age groups? Neurosurgery
8. Bracken MB, Freeman DH Jr, Hellenbrand K: Incidence of acute traumatic hospitalized spinal cord injury in the United States, 1970–1977. Am J Epidemiol
9. Dai LY, Yuan W, Ni B, Liu HK, Jia LS, Zhao DL, Xu YK: Surgical treatment of nonunited fractures of the odontoid process, with special reference to occipitocervical fusion for unreducible atlantoaxial subluxation or instability. Eur Spine J
10. Dickman CA, Greene KA, Sonntag VKH: Traumatic injuries of the cranio-vertebral junction, in Dickman CA, Spetzler RF, Sonntag VKH (eds): Surgery of the Craniovertebral Junction
. New York, Thieme, 1998, pp 175–196.
11. Dickson H, Engel S, Blum P, Jones RF: Odontoid fractures, systemic disease and conservative care. Aust N Z J Surg
12. Dunn ME, Seljeskog EL: Experience in the management of odontoid process injuries: An analysis of 128 cases. Neurosurgery
13. Etebar S, Cahill DW: Failure of transodontoid screw fixation. Case report. J Neurosurg
14. Fleming BC, Krag MH, Huston DR, Sugihara S: Pin loosening in halo-vest orthosis: A biomechanical study. Spine
15. Fujii E, Kobayashi K, Hirabayashi K: Treatment in fractures of the odontoid process. Spine
16. Garfin SR, Botte MJ, Waters RL, Nickel VL: Complications in the use of the halo fixation device. J Bone Joint Surg Am
17. Glaser JA, Whitehill R, Stamp WG, Jane JA: Complications associated with the halo-vest. A review of 245 cases. J Neurosurg
18. Goodman ML, Nelson PB: Brain abscess complicating the use of halo orthosis. Neurosurgery
19. Govender S, Maharaj JF, Haffajee MR: Fractures of the odontoid process. J Bone Joint Surg Br
20. Greene KA, Dickman CA, Marciano FF, Drabier J, Drayer BP, Sonntag VK: Transverse atlantal ligament disruption associated with odontoid fractures. Spine
21. Greene KA, Dickman CA, Marciano FF, Drabier JB, Hadley MN, Sonntag VK: Acute axis fractures. Analysis of management and outcome in 340 consecutive cases. Spine
22. Grob D, Crisco JJ 3rd, Panjabi MM, Wang P, Dvorak J: Biomechanical evaluation of four different posterior atlantoaxial fixation techniques. Spine
23. Hadley MN, Browner CM, Liu SS, Sonntag VK: New subtype of acute odontoid fractures (type IIA). Neurosurgery
25. Hanigan WC, Powell FC, Elwood PW, Henderson JP: Odontoid fractures in elderly patients. J Neurosurg
26. Harrop JS, Przybylski GJ, Vaccaro AR, Yalamanchili K: Efficacy of anterior odontoid screw fixation in elderly patients with Type II odontoid fractures. Neurosurg Focus
27. Jenkins JD, Coric D, Branch CL Jr: A clinical comparison of one- and two-screw odontoid fixation. J Neurosurg
28. Kameyama O, Ogawa K, Suga T, Nakamura T: Asymptomatic brain abscess as a complication of halo orthosis: Report of a case and review of the literature. J Orthop Sci
29. Kirankumar MV, Behari S, Salunke P, Banerji D, Chhabra DK, Jain VK: Surgical management of remote, isolated type II odontoid fractures with atlantoaxial dislocation causing cervical compressive myelopathy. Neurosurgery
30. Koivikko MP, Kiuru MJ, Koskinen SK, Myllynen P, Santavirta S, Kivisaari L: Factors associated with nonunion in conservatively-treated type-II fractures of the odontoid process. J Bone Joint Surg Br
31. Kuntz C 4th, Mirza SK, Jarell AD, Chapman JR, Shaffrey CI, Newell DW: Type II odontoid fractures in the elderly: Early failure of nonsurgical treatment. Neurosurg Focus
32. Lee SH, Sung JK: Anterior odontoid fixation using a 4.5-mm Herbert screw: The first report of 20 consecutive cases with odontoid fracture. Surg Neurol
33. Lennarson PJ, Mostafavi H, Traynelis VC, Walters BC: Management of type II dens fractures: A case-control study. Spine
34. Lomoschitz FM, Blackmore CC, Mirza SK, Mann FA: Cervical spine injuries in patients 65 years old and older: Epidemiologic analysis regarding the effects of age and injury mechanism on distribution, type, and stability of injuries. AJR Am J Roentgenol
35. Majercik S, Tashjian RZ, Biffl WL Harrington DT, Cioffi WG: Halo vest immobilization in the elderly: A death sentence? J Trauma
36. Montesano PX, Anderson PA, Schlehr F, Thalgott JS, Lowrey G: Odontoid fractures treated by anterior odontoid screw fixation. Spine
37. Moon MS, Moon JL, Sun DH, Moon YW: Treatment of dens fracture in adults: A report of thirty-two cases. Bull Hosp Jt Dis
38. Nucci RC, Seigal S, Merola AA, Gorup J, Mroczek KJ, Dryer J, Zipnick RI, Haher TR: Computed tomographic evaluation of the normal adult odontoid. Implications for internal fixation. Spine
39. Ochoa G: Surgical management of odontoid fractures. Injury
40. Pepin JW, Bourne RB, Hawkins RJ: Odontoid fractures, with special reference to the elderly patient. Clin Orthop Relat Res
41. Ryan MD, Taylor TK: Odontoid fracture in the elderly. J Spinal Disord
42. Sasso R, Doherty BJ, Crawford MJ, Heggeness MH: Biomechanics of odontoid fracture fixation. Comparison of one- and two-screw technique. Spine
43. Subach BR, Morone MA, Haid RW Jr, McLaughlin MR, Rodts GR, Comey CH: Management of acute odontoid fractures with single-screw anterior fixation. Neurosurgery
44. Tashjian RZ, Majercik S, Biffl WL, Palumbo MA, Cioffi WG: Halo-vest immobilization increases early morbidity and mortality in elderly odontoid fractures. J Trauma
45. White AA III, Panjabi MM: Clinical Biomechanics of the Spine.
Philadelphia, J.B. Lippincott, 1990, ed 2, pp 610–611.
Agrillo et al. present a small but important series of elderly patients with odontoid fractures (n = 9) treated via an anterior approach. The results are similar to those of previous series demonstrating a higher nonunion rate in the elderly, and ultimately 2 of the patients did not heal successfully. Nevertheless, one can understand the appeal of odontoid screws in the elderly. Although the local preservation of atlantoaxial motion is not only suspect but also of limited clinical significance in these older patients, the reduced surgical morbidity (including the ability to perform the surgery in the supine position, reduced postoperative pain, and lower infection rates) offers distinct advantages. The authors achieved excellent results, and ultimately this strategy (using the less morbid surgery first, and revising only when absolutely necessary) may be the most successful approach in these patients, who are prone to developing complications.
Michael Y. Wang
The authors have extended our knowledge of when it is possible to treat odontoid fractures by direct odontoid screw fixation. In our experience (2), we had patients who self-sorted into 2 groups, those who underwent operations within 6 months of the injury and those whose surgery was performed after 18 months or more, which we termed remote injuries. We tried odontoid screw fixation on both groups and found that the earlier group had good results, with about 90% fusion success. This was true if we treated them within days of their injury or up to the 6-month point. Surgery for the remote injuries, however, was much less successful, leading us to recommend posterior fusion for this group. We did not have any cases, however, within the 6- to 12-month interval, so we could not make a recommendation of one form of treatment over the other for these patients. The present study fills that void and shows that, at least up to 1 year, odontoid screw fixation can be expected to be successful in the majority of cases.
This correlates with the observation that nonunited anterior cervical fusions treated with additional posterior stabilization will usually go on to fuse, even after a substantial period of time, indicating that once it has been well immobilized, the fusion can and will progress. That this will occur even in elderly patients is encouraging, as these patients will not heal well with external immobilization, as Lennarson et al. (3) have shown, and a direct odontoid screw fixation procedure is a quicker procedure and incurs less morbidity than a C1–C2 fusion in the elderly.
To clarify our technique: we do not recommend using cannulated screws over a K-wire because of the risk of advancing the wire and causing neural damage. Our technique, which the authors referenced (1,2), uses a drill guide tube system that allows realignment of the spine and the placement of the screws through this; we feel that this technique is safer. The authors, however, emphasize starting the drill hole low on C2 along its inferior surface, drilling through the apical cortex, and engaging it with the screws, both of which are important. The screw heads, however, should be drawn up tight against the inferior edge of C2 to achieve the lag effect and compression of the odontoid to the body of C2. In Figures 2 and 4 of the article, the screw heads are too far inferior, but since the apical cortex was obviously drilled, this may represent back-out of the screws rather than failure to tighten them enough.
Finally we do not agree with the authors' speculation regarding 1 screw versus 2 screws. A recent analysis of our elderly patient series shows much better success with 2 screws (95%), rather than 1 screw (56%; P = 0.01) in this elderly population (Dailey et al., unpublished data). We believe that this occurs because of better immobilization in weaker osteopenic bone and because the second screw prevents rotation of the odontoid relative to C2, which can occur if they cannot be lagged tightly together. This difference was not seen in younger patients, in whom the results for 1 and 2 screws were not statistically different.
Ronald I. Apfelbaum
Salt Lake City, Utah
1. Apfelbaum RI: Anterior screw fixation of odontoid fractures, in Rengachary SS, Wilkins RH (eds): Neurosurgical Operative Atlas
. Baltimore, Williams & Wilkins, 1992, vol 2, pp 189–199.
2. Apfelbaum RI, Lonser RR, Veres R, Casey A: Direct anterior screw fixation for recent and remote odontoid fractures. J Neurosurg
93 [Suppl]:227–236, 2000.
3. Lennarson PJ, Mostafavi H, Traynelis VC, Walters BC: Management of type II dens fractures: A case-control study. Spine
This small case series of minimally symptomatic/asymptomatic elderly patients with C2 fractures treated in a delayed fashion (at 6–12 months) demonstrates that it is possible to place C2 screws in such patients and that reasonable fusion rates may be obtained (the fusion rate is reported to be 77%, although, from the case descriptions, it seems that 3 of 9 patients failed fixation and another patient had a stable nonunion, for a fusion rate of 55%). Although this fusion rate is not outstanding, it may make delayed C2 anterior screw fixation a reasonable option for the elderly, in whom a less invasive option is particularly appealing.
Daniel K. Resnick
Type II odontoid fractures are relatively common in the elderly. The authors describe 9 patients who presented with odontoid Type II fractures 6 to 12 months after their initial injury. All patients underwent fixation with a single anterior odontoid screw. Successful osseous union was achieved in 7 of the 9 patients. One patient had a fibrous union, and 1 patient failed to achieve fusion. This outcome is somewhat surprising, especially considering the examples provided by the authors. Sclerotic bone seems to have formed at the fracture site, but solid fusion was still achieved. The authors rightly point out the increased complication rate associated with treating these fractures with a halo or collar. Consequently, I will reconsider routinely performing posterior C1–C2 fusion in elderly patients with a delayed odontoid Type II fracture and will consider whether they should instead be treated with anterior screw fixation, as these authors have done.
Volker K.H. Sonntag
Agrillo et al. report a 77% fusion rate in a small group of elderly patients with Type II odontoid fractures. The fractures varied in age from 6 to 12 months. The authors did not “freshen” the fractures, and all patients were immobilized in a collar. Although bone density data are not provided, it can be appreciated from the provided figures that these patients had fairly good bone quality. This is an important consideration when using anterior screw fixation.
Posterior C1–C2 fusion in elderly patients provides more secure fixation, which may be important if there is significant instability or if the bone quality is poor. Many of these patients have already lost some rotatory motion, and the additional degree of rotational restriction is not usually clinically significant.
Vincent C. Traynelis
Iowa City, Iowa