Radiologic anatomy of the spinal dorsal horn at the cervical level (anatomic-MRI correlations)

The spinal dorsal horn is known for its important functional role in the fi eld of transmission and modulation of sensory afferents. Because of this, t he dorsal horn represents a target for numerous analgesic and antispastic p rocedures. Thus, it would be interesting to develop imaging dedicated to th is spinal structure. The purpose of this study was to investigate the radio logic anatomy of the cervical dorsal horn by magnetic resonance imaging (MR I) (1.5T). The first step consisted in the validation of the anatomic infor mation provided by MRI on 5 human cadavers. A spin-echo sequence (T2, 2000/ 45) enabled the demonstration of good correlations between histologic secti ons and axial MRI slices performed at the corresponding cervical levels. Th e second step was the <<in vivo>> exploration of 20 subjects, aiming at the development of a gradient echo sequence (T2*) with a conventional MRI unit , compatible with a routine clinical examination. The dorsal horn was clear ly identified in 77% of the axial slices performed (n = 300). The angle bet ween the dorsal horn axis and the sagittal plane was measured as from 25.5 degrees at C2 to 40 degrees at C8 segments. The results of this anatomico-r adiologic study of the cervical dorsal horn suggest that preoperative MRI c ould be useful to design the surgical approach to this structure, as perfor med during cervical microsurgical drezotomy (DREZ = dorsal root entry zone) for the treatment of selected cases of chronic pain or disabling spasticit y in the upper limbs.