Dorsal Root Entry Zone Coagulation Research Articles

Microsurgical dorsal root entry zone coagulation for chronic neuropathic pain due to spinal cord and/or cauda equina injuries

Microsurgical dorsal root entry zone coagulation for chronic neuropathic pain due to spinal cord and/or cauda equina injuries

Treatment of refractory pain after brachial plexus avulsion with dorsal root entry zone lesions. (Medical School Hannover, Hannover, Germany) Neurosurgery. 2001;48:1269–1275.

Forty‐seven patients with intractable pain after traumatic cervical root avulsions were treated with dorsal root entry zone coagulation between 1980 and 1998. The dorsal root entry zone coagulation procedure was performed 4 months to 12 years after the trauma, and patients were monitored for up to 18 years. Immediately after surgery, 75% of the patients experienced significant pain reduction; this value was reduced to 63% during long‐term follow‐up monitoring. Nine patients experienced major complications including subdural hematomas and motor weakness of the lower limb. Improved coagulation electrodes with thermistors that could produce smaller and more accurate lesion sizes, which were introduced in 1989, significantly reduced the number of complications. Conclude that long‐term follow‐up monitoring of patients who underwent the dorsal root entry zone coagulation procedure in the cervical cord indicated that long‐lasting satisfactory relief is possible for the majority of individuals with acceptable morbidity rates.Comment by Ron Pawl, M.D. This paper is important for several reasons. It provides a long‐term follow‐up on patients suffering intractable pain after cervical nerve root avulsion from the cord, and results of dorsal root entry zone lesioning using the thermocoagulation technique, where lesions are made at 1 mm intervals covering the length of the cord and one level above and one below the levels of the roots involved. Thirty‐nine of 47 patients had 63% reduction of pain in follow‐up of 2 to 18 years (14 year average). The authors also reported that 9 patients experienced major complications including subdural hematomas and lower extremity weakness, which they attribute to the electrodes used to make the lesions prior to 1989. Using an improved electrode since that time, they report fewer complications. Also, the authors note no correlation between the duration of the pain, the time between the trauma and the surgery, and the time of onset of the pain after trauma with the outcome of the surgery, indicating the procedure is effective, even when carried out years after the onset of the pain. This last concept puts a damper on the idea of centralized pain memory as the mechanism for the chronic pain.

Treatment of Refractory Pain after Brachial Plexus Avulsion with Dorsal Root Entry Zone Lesions

Significant numbers of patients experience intractable pain after brachial plexus root avulsions. Medications and surgical procedures such as amputation of the limb are often not successful in pain treatment. Forty-seven patients with intractable pain after traumatic cervical root avulsions were treated with dorsal root entry zone coagulation between 1980 and 1998. The dorsal root entry zone coagulation procedure was performed 4 months to 12 years after the trauma, and patients were monitored for up to 18 years (average follow-up period, 14 yr). Immediately after surgery, 75% of patients experienced significant pain reduction; this value was reduced to 63% during long-term follow-up monitoring. Nine patients experienced major complications, including subdural hematomas (n = 2) and motor weakness of the lower limb (n = 7). Improved coagulation electrodes with thermistors that could produce smaller and more-accurate lesion sizes, which were introduced in 1989, significantly reduced the number of complications. Central deafferentation pain that persists and becomes intractable among patients with traumatic cervical root avulsions has been difficult to treat in the past. Long-term follow-up monitoring of patients who underwent the dorsal root entry zone coagulation procedure in the cervical cord indicated that long-lasting satisfactory relief is possible for the majority of individuals, with acceptable morbidity rates.

Subpial spinal evoked potentials in patients undergoing junctional dorsal root entry zone coagulation for pain relief

Seven patients with complete avulsion of the brachial plexus underwent junctional coagulation lesions of the dorsal root entry zone (DREZ) for relief of intractable pain in the paralyzed arm. Intra-operative monitoring by recording spinal cord somatosensory evoked potentials (SEP) resulting from tibial nerve stimulation was done using subpial recording electrodes situated dorsal to the posterior median sulcus at the C4 and T2 segment. SEP on the normal side showed an initial positive wave and two negative waves followed by a group of high frequency waves of relatively high amplitude which continued into high frequency, low amplitude potentials. The conduction velocity of the fastest spinal evoked potential components were, on average, 86 m/s. Recordings from the side of avulsion revealed a steep positive potential of high amplitude which appeared in five patients prior to the creation of the DREZ lesion. This effect was assumed to be secondary to spinal cord damage caused by avulsion. During the DREZ coagulation the SEP from the unaffected side did not change. On the side of DREZ coagulation the velocity of the fastest fibres decreased. Four patients reported sensory deficits after the operation, which were transient in three. In one of these patients, the first two negative potentials disappeared. In the fourth patient, who had permanent sensory deficits, the positive steep potential appeared after generation of the lesion. Our results point to the usefulness of the subpial SEPs monitoring during microneuro-surgical procedures on the spinal cord to provide further insight into evoked electrical activity of the normal and injured spinal cord, and to minimize post-operative neurological morbidity.

Dorsal root entry zone coagulation for intractable sciatica.

Chronic back and leg pain which is unresponsive to medical and/or surgical treatment is a common and difficult neurosurgical problem. Twelve patients with this condition underwent dorsal root entry zone coagulation of that region of the conus medullaris which correlated with the pain. Only 2 patients had a favorable result. The implications of this finding are discussed.

Successful treatment of phantom pain with dorsal root entry zone coagulation.

We studied 22 patients with amputation due to trauma, gangrene, or cancer. All developed postamputation pain, underwent a dorsal root entry zone (DREZ) procedure, and were followed from 6 months to 4 years after surgery. Overall, only 8 (36%) of these 22 patients had pain relief. However, good results were obtained in 6 (67%) of 9 patients with phantom pain alone, and in 5 (83%) of 6 patients with traumatic amputations associated with root avulsion. Poor results were obtained in patients with both phantom and stump pain, or stump pain alone. The DREZ procedure has a well-defined, but limited role in the treatment of postamputation pain.

Dorsal Root Entry Zone Lesions (Nashold's Procedure) in Brachial Plexus Avulsion

Dorsal root entry zone coagulation (DREZ) lesions for pain were made in 41 patients at the National Hospitals during 1980 through 1983. In 34 patients the operation was an attempt to relieve pain due to avulsion of the brachial plexus. Of these patients, 95% were male and 91% had received their injury in road traffic accidents. The follow-up period is 4 to 44 months. Pain relief was good in 62%, fair in 24%, and poor in 14%. Postoperative motor or sensory changes occurred in 50% of the patients, but these were significant in only 12%. In later patients in this series, pre-, peri-, and postoperative monitoring of somatosensory evoked potentials was used. Evoked potential monitoring indicated subclinical posterior column damage ipsilateral to avulsion before DREZ lesion making in about 50% of the cases; in some cases, postoperative changes were detected. (Neurosurgery 15:966-968, 1984)

Dorsal root entry zone lesions (Nashold's procedure) in brachial plexus avulsion.

Dorsal root entry zone coagulation (DREZ) lesions for pain were made in 41 patients at the National Hospitals during 1980 through 1983. In 34 patients the operation was an attempt to relieve pain due to avulsion of the brachial plexus. Of these patients, 95% were male and 91% had received their injury in road traffic accidents. The follow-up period is 4 to 44 months. Pain relief was good in 62%, fair in 24%, and poor in 14%. Postoperative motor or sensory changes occurred in 50% of the patients, but these were significant in only 12%. In later patients in this series, pre-, peri-, and postoperative monitoring of somatosensory evoked potentials was used. Evoked potential monitoring indicated subclinical posterior column damage ipsilateral to avulsion before DREZ lesion making in about 50% of the cases; in some cases, postoperative changes were detected.