Atlantoaxial instability in Lesch-Nyhan syndrome.

STUDY
DESIGN: A clinical case report of two brothers with Lesch-Nyhan syndrome found to have atlantoaxial instability is reported.
OBJECTIVES: To report the clinical and radiologic findings and the operative outcome in these patients. SUMMARY OF BACKGROUND DATA: Both patients had biochemically proven Lesch-Nyhan syndrome. No previous cases of cervical instability have been reported in this group of patients.
METHODS: The first patient presented with neck pain and progressive quadriplegia. Radiology including computed tomography scanning showed fracture of the tip of the odontoid and forward subluxation of the atlas. He was treated with a C1-C2 Gallie fusion. The second patient (his brother) was found to have similar radiologic findings but had not developed quadriplegia. He has not required surgery.
RESULTS: At surgery, attempted correction of the subluxation produced severe bradycardia. An in situ fusion was performed that relieved the patient's neck pain. The child's neurologic status has remained the same during a 16-month follow-up period, despite failure of the posterior wire fixation 12 months after surgery.
CONCLUSIONS: Patients with Lesch-Nyhan syndrome may develop atlantoaxial instability with subsequent neck pain and quadriplegia that may be masked by their underlying disease. Posterior fusion produced symptomatic relief but no improvement in neurologic status in our patient. Posterior fusion probably should be augmented by rigid cervical immobilization until fusion is confirmed in this type of patient.