Micro-surgical DREZotomy (MDT) – tries to selectively interfere the small nociceptive and the large myotatic fibres (situated laterally, centrally and respectively), while sparing the large lemniscal fibres which are reordered medially. It also enhances the inhibitory mechanisms of Lissauer’s tract and dorsal horn.
MDT is indicated in bedridden paraplegic patients as well as in hemiplegic patients with painful hyper spasticity. It can also be used to treat neurogenic bladder with uninhibited detrusor contractions.
MDT consists of:
- 3 mm deep microsurgical incision is taken in the dorso-lateral sulcus.
- The incision is done at an angle of 35 degrees for cervical level and at 45 degrees for lumbo-sacral level.
- After reaching to DREZ, it is penetrated in its ventrolateral aspect, at the level of the entrance of rootlets which are involved in spasticity.
- To study the motor responses during procedure neurophysiological monitoring with paired needle electrodes is used.
- Somatosensory evoked potentials (SSEPs) recording is least important but still useful in testing the function of the spinal cord intraoperatively.