Dorsal root entry zone localization using direct spinal cord stimulation: an experimental study

1995 ◽  
Vol 82 (4) ◽  
pp. 592-594 ◽  
Author(s):  
Mahmood Fazl ◽  
David A. Houlden
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Stimulation ◽  
Dorsal Root ◽  
Dorsal Spinal Cord ◽  
Specific Stimulus ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Dorsal Spinal

✓ Direct spinal cord stimulation and recording was performed in five dogs to identify the dorsal root entry zone (DREZ) and long tracts within the dorsal and dorsolateral spinal cord using electrophysiological mapping techniques. Intrathecal recordings were obtained from sites distal to the site of stimulation. Conduction velocity in the fastest conducting fibers was higher following low-intensity stimulation of the dorsolateral spinal cord than after dorsal spinal cord stimulation. The evoked response was larger following dorsolateral than dorsal spinal cord stimulation at a specific stimulus intensity. This technique is useful in identifying the DREZ using electrophysiological criteria alone.

Spinal cord mapping with evoked responses for accurate localization of the dorsal root entry zone

1995 ◽  
Vol 82 (4) ◽  
pp. 587-591 ◽  
Author(s):  
Mahmood Fazl ◽  
David A. Houlden ◽  
Zelma Kiss
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Neurological Deficits ◽  
Intractable Pain ◽  
Specific Stimulus ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Accurate Localization

✓ Direct spinal cord stimulation and recording techniques were used intraoperatively to localize the dorsal root entry zone (DREZ) in four patients with brachial plexus avulsion and severe intractable pain. The spinal cord was stimulated by a cordotomy needle placed on the pia-arachnoid at the DREZ or the dorsal or dorsolateral aspect of the spinal cord. Recordings were obtained from a subdural silver ball electrode placed rostral or caudal to the stimulation site. Spinal cord conduction velocity was significantly faster following dorsolateral stimulation than dorsal stimulation (mean = 66 and 45 m/sec respectively). The spinal cord evoked potential was significantly larger in amplitude following dorsolateral stimulation than dorsal stimulation at a specific stimulus intensity. Stimulation at the DREZ failed to evoke a response. These neurophysiological phenomena helped to accurately localize the DREZ before DREZ lesioning was undertaken. There were no untoward neurological deficits related to the DREZ lesions and all patients had satisfactory pain relief following the procedure. Intraoperative spinal cord mapping facilitates accurate DREZ localization when the DREZ cannot be visually identified.

scholarly journals Neurosurgical treatment of pain

2006 ◽  
Vol 59 (9-10) ◽  
pp. 450-455
Author(s):  
Eugen Slavik
Keyword(s):  
Spinal Cord ◽  
Chronic Pain ◽  
Surgical Treatment ◽  
Spinal Cord Stimulation ◽  
Dorsal Root ◽  
Neurosurgical Procedures ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Root Entry Zone ◽  
Deep Brain

Introduction. Surgical treatment of chronic pain includes destructive procedures (neurectomy, rhizotomy, sympathectomy), often referred to as ablative, and accompanied by high morbidity and mortality rates. Surgical treatment of pain. During the past three decades, thanks to current knowledge on chronic pain mechanisms and technological developments, such as improved microsurgical and stereotactic techniques, guided by computerized tomography, magnetic resonance imaging and neural tissue impedance monitoring, the majority of ablative procedures have been replaced by new methods. Among them, a few can be considered as selectively and minimally ablative (microsurgical spinothalamic cordotomy, dorsal root entry zone lesions, limited midline myelotomy) and others as neuroaugumentative procedures for neuromodulatory processes (deep brain structures and spinal cord stimulation, drug-delivery systems). Neurosurgical procedures. Cordotomy is very effective in pain treatment and it may produce complete abolishment of pain, especially in patients suffering from neoplastic invasion of the brachial plexus (Pancoast?s syndrome) or lumbosacral plexus. Dorsal root entry zone operation is generally the only treatment option for pain due to root avulsion and segmental pain in spinal cord injury. Spinal cord stimulation is useful in management of pain following peripheral nerve injury. Deep brain stimulation is a promising treatment of central pain. Conclusion. The purpose of this review is to draw attention to neurosurgical approaches to treatment of chronic and opioid-resistant pain. .

Somatosensory function following dorsal root entry zone lesions in patients with neurogenic pain or spasticity

1991 ◽  
Vol 74 (6) ◽  
pp. 916-932 ◽  
Author(s):  
Daniel Jeanmonod ◽  
Marc Sindou
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Dorsal Root ◽  
Neurogenic Pain ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Somatosensory Function ◽  
Fine Print

✓ The goal of this study was to assess the effects of the dorsal root entry zone (DREZ) lesioning procedure, microsurgical DREZ-otomy (MDT), on spinal cord somatosensory function based on peri- and intraoperative clinical and electrophysiological data. The study was performed prospectively on a series of 20 patients suffering from either chronic neurogenic pain or spasticity. Physiological observations were made of the intraoperative evoked electrospinographic recordings as collected from the surface of the spinal cord. The MDT procedure produced analgesia or severe hypalgesia, moderate hypesthesia, and only slight deficits in proprioception and cutaneous spatial discrimination on the body segments operated on. These clinical data correlated well with evoked electrospinographic recordings, which showed a moderate effect of MDT on presynaptic compound action potentials recorded from the spinal cord (N11 and N21), a partial or even reversible effect on the cortical postcentral N20 wave, a more marked effect on the postsynaptic dorsal horn waves N13 and N24 related to large primary afferent fibers, and a disappearance of dorsal horn waves related to finer afferents (N2 and possibly N3). These data provide evidence for an acceptably selective action of MDT on spinal cord nociceptive mechanisms, and for a partial, often slight, involvement of the other somatosensory domains. The presence of abnormal evoked electrospinographic waves is discussed in relation to the mechanisms of neurogenic pain and spasticity. The hypothesis of a “retuning” of the dorsal horn as the mode of action of MDT is presented.

Dorsal root entry zone microcoagulation for spinal cord injury—related central pain: operative intramedullary electrophysiological guidance and clinical outcome

2002 ◽  
Vol 97 (2) ◽  
pp. 193-200 ◽  
Author(s):  
Scott Falci ◽  
Lavar Best ◽  
Rick Bayles ◽  
Dan Lammertse ◽  
Charlotte Starnes
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Central Pain ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Cord Injury ◽  
Electrical Data ◽  
Fine Print

Object. Surgically created lesions of the spinal cord dorsal root entry zone (DREZ) to relieve central pain after spinal cord injury (SCI) have historically resulted in modest outcomes. A review of the literature indicates that fair to good relief of pain is achieved in approximately 50% of patients when an empirical procedure is performed. This study was undertaken to determine if intramedullary electrical guidance in DREZ lesioning could improve outcomes in patients with SCI-induced central pain. Additionally, electrical data were used to determine if the spinal cord could be somatotopically mapped with regard to this pain of central origin. Methods. Forty-one patients with traumatic SCI and intractable central pain underwent DREZ lesioning in which intramedullary electrical guidance was conducted. In nine patients, recording of DREZ-related spontaneous electrical hyperactivity guided the lesioning process. In 32 patients, recording of DREZ-induced evoked electrical hyperactivity during transcutaneous C-fiber stimulation (TCS) additionally guided lesioning. The follow-up period ranged from 1 to 7 years. The analyzed electrical data allowed for somatotopic mapping of the spinal cord. Conclusions. Intramedullary electrical guidance of DREZ lesioning substantially improves pain outcomes in patients with traumatic SCI—induced central pain, compared with an empiric technique. The best outcome occurs when DREZ-related spontaneous electrical hyperactivity and evoked hyperactivity during TCS are both used to guide the DREZ lesioning procedure. With such guidance, 100% relief of pain was achieved in 84% of patients and 50 to 100% relief of pain in 88%. Somatotopic mapping of the electrical data led to a proposed pain mechanism for below-level pain, implicating the sympathetic nervous system.

Dorsal root entry zone lesions for pain relief

1979 ◽  
Vol 51 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Blaine S. Nashold ◽  
Roger H. Ostdahl
Keyword(s):  
Spinal Cord ◽  
Pain Relief ◽  
Brachial Plexus ◽  
Dorsal Root ◽  
Dorsal Column ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Arm Pain ◽  
Root Entry Zone

✓ Arm pain due to avulsion of the cervical dorsal roots of the brachial plexus may become intractable, ameliorated little, if at all, by contemporary medical or surgical treatment. Severe and sudden trauma to the neck, shoulder, or arm is the usual cause of avulsion of the cervical rootlets. The injury may result in complete sensorimotor paralysis of the involved extremity, or a partial deficit if only a few rootlets are involved. Previous therapies have included stellate block, sympathectomy, high cervical cordotomy, rhizotomy, transcutaneous stimulation, dorsal column stimulation, mesencephalic tractotomy, cingulotomy, and the use of narcotics. The extent of the pathological change in the spinal cord following root avulsion is not completely known; at the time of operation, abnormalities frequently noted included ipsilateral atrophy of the dorsal aspect of the cord, dense arachnoid scarring, microcyst formation, and loss of both dorsal and ventral roots. The cervical myelogram is abnormal, although not necessarily pathognomonic of the extent of injury. The surgical technique of coagulation of the dorsal root entry zone is discussed, and the results and morbidity in 21 patients are reviewed. Thirteen patients (67%) continue to have good pain relief, with follow-up periods ranging from 6 months to 3½ years. Three patients with extremity pain from other causes are included in the series. Clinical observations suggest the possibility that pain resulting from brachial plexus avulsion originates from pathophysiological changes in the injured dorsal horn of the spinal cord. This report is a discussion of a new technique aimed at destruction of the dorsal root entry zone for relief of chronic extremity pain.

Laser-induced dorsal root entry zone lesions for pain control

1983 ◽  
Vol 59 (5) ◽  
pp. 884-886 ◽  
Author(s):  
Walter J. Levy ◽  
Alan Nutkiewicz ◽  
Q. Michael Ditmore ◽  
Clark Watts
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Scar Tissue ◽  
Intractable Pain ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Cord Injury ◽  
Alternative Means

✓ Dorsal root entry zone lesions have been documented as effective for control of intractable pain in patients with brachial plexus avulsion or severe spinal cord injury. These lesions are usually made with the radiofrequency technique. The authors report three cases in which the CO2 laser was used as an alternative means of making the lesions. This latter technique provided effective pain relief in two of the patients and was efficient to use. It was noted that the presence of overlying scar tissue can be deceptive in judging the depth of the lesion made with the laser. The CO2 laser provided a means of producing controlled spinal cord lesions which may be more precise than the radiofrequency method.

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