Grisel Syndrome

Subluxation of the atlantoaxial joint secondary to inflammatory processes (pharyngitis and pharyngeal abscess) and head and neck surgery. Major anesthetic implications (danger of quadriplegia, especially during laryngoscopy and tracheal intubation; massive bacterial pulmonary contamination if there is a rupture of a pharyngeal abscess).

Nontraumatic Atlanto-Axial Subluxation.

Although first described in 1830 by the Scottish physician Charles Bell, it is named after the French otorhinolaryngologist P. Grisel who described the features in 1930.

Rare. Literature suggests approximately 1:100,000,000 per year. Males and females are affected equally. Usually affects children, but may be diagnosed late into adulthood.

Not inherited disorder.

Infection in the head and neck area spreads toward the upper cervical vertebrae. The inflammation causes laxity of the atlantoaxial ligament complex, leading to anterior subluxation of the atlas on the axis. This probably follows rupture of the transverse ligament and may result in spinal cord compression. The cause of infection may be (1) postsurgery: mastoidectomy, tonsillectomy, adenoidectomy, removal of tumors, or choanal atresia repair, (2) contiguous infection: rhinopharyngitis, tonsillitis, abscess (retropharyngeal to alveolar), or ear infections, or (3) other more rare associations, such as acute rheumatic fever or inflammatory bowel disease.

Usually clinical and it may be missed for months until significant symptoms occur. Radiographs are of minimal value in the first 4 weeks, although flexion-extension views may be suggestive. CTand MRI scans usually confirm the presence of rotational dislocation or anterior subluxation. Flexible nasopharyngoscopy is useful.

Usually presents with progressive unrelenting throat and neck pain followed by torticollis and subluxation. There is often little systemic reaction. The torticollis is usually acute and often occurs with sleep or minimal motion. Neurologic complications occur in approximately 15% of cases and range from radiculopathy to myelopathy, transient or permanent paraplegia, and even death. This can occur if the atlas becomes dislocated and can occur following only minimal trauma. Treatment includes antibiotics, surgical drainage of pus collections, bony stabilization and neurologic protection. In the acute phase of the disease, spinal protection often involves spinal traction treatment. Chronic disease may require fixation, which is commonly performed by an anterior approach.

Once the diagnosis is made, the major concerns are spinal stability and the degree of neurologic compromise. This is usually well established by clinical examination and scan results. Assessment of the cause is important and may involve consideration of a retropharyngeal or other upper airway abscess. Full assessment of the neck is required because movement is usually severely restricted regardless of stability.

Tracheal intubation may be extremely difficult for several reasons: (1) unstable upper cervical spine with increased risk for any movements, such as jaw support for face mask; (2) high risk of complications if neurologic abnormalities are present; (3) causal abscess or other airway inflammation/infection; (4) limited neck movement and mouth opening because patient may be in traction; and (5) positioning is best performed awake when neurologic assessment is optimal. The position may be prone, although outcome is often better via an oral approach, in which case a nasal armored tube is preferred. Awake intubation using a fiberoptic scope is the technique of choice but often is impractical in children. This may be possible, however, under a spontaneously ventilating gas or intravenous general anesthetic technique; and spinal cord monitoring can be used to assess cord integrity. Once intubated and positioned, a wake-up test is used by some to establish cord function; but again, this is difficult and may be unpredictable in children. Maintenance of spontaneous ventilation is a way to ensure clinical upper cord function monitoring. Shared airway may lead to surgical and anesthetic problems, such as endotracheal tube compression and accidental extubation/disconnection.

Use of neuromuscular blockade is best avoided because of loss of spinal cord integrity monitoring via respiration and response to motor and/or sensory stimulations (if unable to perform wake-up test). If succinylcholine is deemed necessary, fasciculations should be avoided (precurarization), since they may pose a serious risk to spinal stability. Induction with inhalational general anesthesia, intravenous propofol infusion, or ketamine may be considered.

Congenital causes of atlantoaxial instability may include the following disorders:

• Os odontoideum (absent, hypoplastic, or incompletely fused dens to body of C2). Atlantoaxial instability, as seen in Morquio syndrome (mucopolysaccharidosis IV), Osteogenesis imperfecta, and Trisomy 21.