Congenital absence of lumbar facets as a cause of lower-back pain.

Unilateral arch hypertrophy secondary to congenital absence of lumbar articular facets is a rare condition of still undetermined etiology. Most symptomatic cases had a history of mild trauma. Radiologic criteria using plain films and CAT scan are available to make the diagnosis of unilateral arch hypertrophy and the specific defects that cause this condition. Awareness of these signs by the orthopedic community may prove helpful in recognizing this anomaly as a cause of lower-back pain in the future. It would seem logical to conclude that the source of pain in patients with this congenital anomalies may be due to microfracture of the hypertrophic side caused by the concentration of stresses. Treatment of this condition varies, and too few cases are reported to draw any conclusions. A conservative approach of bedrest and immobilization should be attempted first. However, if this regime proves unsuccessful after a long well-documented trial, fusion seems to offer a good prognosis in the cases thus far treated by this method.