Atlanto Axial Fusion
By Sam Corbin
Atlantoaxial fusion is a surgical technique used to correct instability between the C1 and C2 vertebrae. Instability at the atlantoaxial joint can be caused by multiple pathologies. Fractures of the vertebrae due to trauma, Down syndrome (DS) and rheumatoid arthritis (RA) are some of the more common pathologies associated with atlantoaxial instability. Atlantoaxial fusion protects against nuerological compromise secondary to vertebral subluxation.
The Atlantoaxial joint is comprised of the C1 and C2 vertebrae. The atlas (C1) is in direct contact superiorly with the occipital condyle and inferiorly with the facets of the axis C2. The axis (C2) is located inferiorly to the atlas and has an adontoid process and bifid spinous process. The adontoid process of C2 is attached to the arch of C1 via the transverse and alar ligaments.1 This joint is responsible for 35-40 degrees of the rotation that occurs in the cervical spine.2
It has been found that 8-10% of patients with Down Syndrome have atlantoaxial instability.3 Researchers have found incidences of subluxation, due to atlantoaxial instability, as high as 61% of patients with RA.4 Over a 14 year period surgeons using screw and endplate fixation method encountered a 17% prevalence in patients after trauma.5
Patients will present with the following symptoms: Severe muscle spasm, unwilling to move head into flexion, lump in throat, Lip or facial paresthesia, severe headache, dizziness, nausea, vomiting, soft end feel, nystagmus and pupil changes.6
Radiology: Lateral, Dynamic Open and Closed mouth views can be used to assess the stability of the atlantoaxial joint.7
(Pic from http://www.ceessentials.net/article20.html)
Special Orthopedic Tests:
Transverse ligament stress test: The tester supports the patients head with both hands while she lies in supine. The tester’s index fingers should be between C2 and the occiput. The tester will then lift the patients head without neck forward flexion. If symptoms are elicited within 10 – 20 seconds the test is positive.7
Lateral Flexion Alar Ligament stress test: The tester will grab the spinous process and lamina of C2 while the patient is in supine. The tester will then laterally flex the patients head. A negative result is a firm end feel with little movement of C2.7
Fusion of the atlantoaxial joint may be achieved by many various methods that use bone grafts, wire, screws and plates to restore stability between C1 and C2 vertebrae. One method considered by many surgeons to be the gold standard is the Magerl’s method.8 The Magerl method includes the placement of transarticular screws through C1 and C2 with the use of sublaminar wire.
Two examples of atlantoaxial fusion:
(Video from: http://www.youtube.com/watch?v=KJHNGf4-Izg)
(Video from: http://www.youtube.com/watch?v=ZRcafQ3xLSs)
It was posed in a 2005 review, written by Bhargava et al, that “physical therapy modalities” are effective in managing neck pain after fusion.9 However, after a thorough search of Pubmed, Medline, Cochrane database of systematic reviews, Science direct and Cinahl databases, guidelines for the use of specific physical therapy modalities were not found. During the acute stage of healing, the use of cryotherapy to reduce postoperative pain and swelling may be considered. Superficial thermotherapy and transcutaneous electrical nerve stimulation may also be used for managing residual stiffness and neck pain after healing of surgical site. The use of ultrasound is contraindicated because of the deep heating effect the sound waves can have on the metal hardware holding the vertebrae.
1. Drake RL, Vogl W and Mitchell AW. Grays anatomy for students. 2nd ed. Philadelphia, PA: Churchill Livingstone Elsevier; 2005.
2. Neumann DA. Kinesiology of the musculoskeletal system foundations for rehabilitation. 2nd ed. St. Louis, MO: Mosby Elsevier; 2010.
3. Ali FE, et al. Cervical spine abnormalities associated with Down syndrome. International Orthopedics. 2006. 30: 284-289.
4. Clarke M, et al. Long-term incidence of subaxial cervical spine instability following cervical arthrodesis surgery in patients with rheumatoid arthritis. Surgical neurology. 2006; 66(2):136-140.
5. Goel A, et al. Atlantoaxial fixation using plate and screw Method: A Report of 160 Treated Patients. Neurosurgery. 2002; 51(6):1351-1357.
6. Magee DJ. Orthopedic physical assessment. 5th ed. St. Louis, MO: Saunders Elsevier; 2008.
7. Fujiwara S, et al. Dynamic close-mouth view radiograph mthod for the diagnosis of lateral dynamic instability of the atlantoaxial joint. Clinical imaging. 2010; 34:375-378.
8. Bahadur R, et al. Transarticular screw fixation for atlantoaxial instability: Modified Magerl’s technique in 38 patients. Journal of orthopedic surgery and research. 2010; 5(1): 87.
9. Bhargavaa A, Gelbb D0, Ludwigb S, et al. Nonoperative management of postoperative neck pain
following a fusion. Current Opinion in Orthopaedics.2005;16:200-209.