[De Anquin disease or spinous engagement syndrome]

We report on a rare disorder called de Anquin's disease or spinous engagement or impingement syndrome. Low back pain in this specific syndrome probably combined with sciatica is caused by a hypertrophic spinous process in combination with a spina bifida occulta of an underlying vertebra which leads to compression of the neural structures beneath. Mostly the enlarged spinous process is seen at the level L5 and the spina bifida occulta at the level S1. Between 1981 and 1993 six patients were treated surgically after long-lasting periods of conservative therapy by resection of the hypertrophic spinous process combined with revision of the nerve roots and division of adhaesions. All patients had been reexamined clinically and radiologically. Up to now three of six patients are free of all symptoms, pain diminished in two others. The back pain situation is unchanged in only one patient.