Andrea Bolognini

Posterior retroextramarginal disc hernia (PREMDH): Definition, diagnosis, and treatment

BACKGROUND Detachment of the posterior part of the lumbar vertebral ring apophysis has been reported by many authors, associated or not with disc prolapse, and has been ascribed to various mechanisms, although the relationship between the two pathologies remains unclear. METHODS We studied 26 patients (17 males and 9 females; mean age, 34.3 years) suffering from a lumbar disc herniation with nontraumatic detachment of the ring apophysis. Investigations included standard X ray, computed tomography (CT), tridimensional CT, and magnetic resonance imaging. Nineteen patients were operated on by microsurgical discectomy and removal of bone fragments. RESULTS Clinical and neuroradiologic features of herniated disc associated with detachment of the ring apophysis have been recognized and have led to the definition of posterior retroextramarginal disc herniations. A further classification is suggested, considering two morphological types that imply clinically distinctive features and a different surgical approach. In all operated cases, removal of the bone fragments was necessary and the results were good. CONCLUSIONS Our observations led us to postulate a common mechanism in the pathogenesis of disc herniation with nontraumatic detachment of the ring apophysis. They should be distinguished from other calcifications of the disc because a proper surgical technique, including removal of apophyseal fragments, is required.

Abnormalities of the soleus H-reflex in lumbar spondylolisthesis: a possible early sign of bilateral S1 root dysfunction.

Using routine electrodiagnostic procedures, the authors searched for physiologic evidence of nerve root compromise in patients with chronic mechanical perturbation to the lumbar spine. They examined 37 patients with spondylolisthesis and various degrees of degenerative changes in the lumbar canal. Clinical and neurophysiologic findings were compared with data obtained from 36 healthy persons. The soleus H-reflex appeared to be a sensitive indicator of sensory fiber compromise at the S1 root level, because changes correlated well with the focal sensory signs and preceded clinical and electromyographic signs of motor root involvement. When these occurred, the clinical findings were consistent with a more severe nerve root deficit and with radiographic evidence of neural compression. The greater sensitivity of the soleus H-reflex may be related to the pathophysiologic events that occur at the lesion site.