Intraoperative evoked potentials recorded in man directly from dorsal roots and spinal cord

1985 ◽  
Vol 62 (5) ◽  
pp. 680-693 ◽  
Author(s):  
Blaine S. Nashold ◽  
Janice Ovelmen-Levitt ◽  
Robbin Sharpe ◽  
Alfred C. Higgins
Keyword(s):  
Spinal Cord ◽  
Dorsal Root ◽  
Mean Amplitude ◽  
Dorsal Column ◽  
Intractable Pain ◽  
Neurosurgical Procedures ◽  
Negative Wave ◽  
Content Type ◽  
Root Entry Zone ◽  
Dorsal Columns

✓ Direct spinal cord surface recordings of evoked spinal cord potentials have been made in 26 patients during neurosurgical procedures for intractable pain. Monopolar recordings at the dorsal root entry zone after peripheral nerve stimulation have been made at multiple levels for segmental localization and to monitor the state of the afferent path and dorsal horn. Dorsal root and dorsal column conduction has been tested on diseased and intact sides. Normal afferent conduction velocity was found to have an overall mean of 61.33 m/sec for cervicothoracic and lumbosacral peripheral nerves, and 50 m/sec for the dorsal columns. The normal mean amplitude for the slow negative wave (N1) recorded at the root entry was 52.54 µV, while that for the dorsal column conducted response recorded within 4 cm of the stimulus point on the dorsal columns was 347.5 µV. Several different placements of stimulating and recording electrodes are described, as well as their application. An interpretation of the resulting data is proposed.

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.

Intractable pain of spinal cord origin: clinical features and implications for surgery

1992 ◽  
Vol 77 (3) ◽  
pp. 373-378 ◽  
Author(s):  
Ronald R. Tasker ◽  
Gervasio T. C. DeCarvalho ◽  
Eugen J. Dolan
Keyword(s):  
Spinal Cord ◽  
Clinical Features ◽  
Surgical Procedures ◽  
Brain Stimulation ◽  
Dorsal Root ◽  
Intractable Pain ◽  
Vertebral Level ◽  
Entry Zone ◽  
Content Type ◽  
Root Entry Zone

✓ The clinical features and types of pain affecting 127 patients with central pain caused by lesions in the spinal cord were studied and correlated with the results of surgical procedures performed on 103 of them. The surgical procedures consisted of percutaneous cordotomy in 39 cases, cordectomy in 12, dorsal root entry zone (DREZ) surgery in four, dorsal cord stimulation in 35, and brain stimulation in 13. The three most common types of pain in the 127 patients were characterized as: steady in 95% of cases, intermittent (usually shooting) in 31%, and evoked (allodynia, hyperpathia, or hyperesthesia) in 45%. Steady pain was usually causalgic (74.8%) or dysesthetic (27.6%). The only obvious clinical correlation with pain type was the association of intermittent pain with lesions at the T10-L2 vertebral level. Destructive surgery (cordotomy, DREZ surgery, or cordectomy) affected the three chief types of pain differently from treatment with cord or brain stimulation. Destructive surgery resulted in reduction of steady pain in 26% of affected cases, of intermittent pain in 89%, and of evoked pain in 84%, while stimulation resulted in pain reductions in 36%, 0%, and 16% of cases, respectively. The differential effect of destructive surgery on steady and intermittent pain is consistent with published experience. These observations suggest differing mechanisms for the three types of pain.

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.

DREZ lesions for relief of pain related to spinal cord injury

1986 ◽  
Vol 65 (4) ◽  
pp. 465-479 ◽  
Author(s):  
Allan H. Friedman ◽  
Blaine S. Nashold
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Pain Relief ◽  
Intractable Pain ◽  
Content Type ◽  
Root Entry Zone ◽  
Pain Syndromes ◽  
Cord Injury ◽  
Good Pain Relief

✓ Fifty-six patients with intractable pain following a spinal cord injury were treated with dorsal root entry zone (DREZ) lesions. After a follow-up period ranging from 6 months to 6 years, 50% of patients had good pain relief. Certain pain syndromes tended to respond better to DREZ lesions than did others. Patients with pain extending caudally from the level of the injury and patients with unilateral pain were most likely to obtain pain relief from the procedure; diffuse pain and predominant sacral pain did not respond as well.

Percutaneous epidural stimulation of the spinal cord for relief of pain

1978 ◽  
Vol 48 (3) ◽  
pp. 323-328 ◽  
Author(s):  
Bruno J. Urban ◽  
Blaine S. Nashold
Keyword(s):  
Spinal Cord ◽  
Dorsal Column ◽  
Long Term Results ◽  
Percutaneous Technique ◽  
Intractable Pain ◽  
Epidural Stimulation ◽  
Content Type ◽  
Major Operation ◽  
Stimulation Of

✓ Percutaneous epidural stimulation of the spinal cord was carried out in 20 patients with intractable pain. The procedure proved simple, and no major complications were encountered. The long-term results were comparable to the results obtained after a dorsal column stimulator implant by laminectomy. The percutaneous technique allowed extended trial stimulation without committing the patient to a major operation. Those patients in whom stimulation did not alleviate pain could be identified during a 2-week observation period, and the system could be removed easily. Seven patients were placed on chronic autostimulation and only one of those failed to experience continuing pain relief throughout the follow-up time of up to 2 years. It is concluded that percutaneous epidural stimulation constitutes a valid alternative to dorsal column stimulator implantation.

Spinal evoked potentials from the motor tracts

1983 ◽  
Vol 58 (1) ◽  
pp. 38-44 ◽  
Author(s):  
Walter J. Levy
Keyword(s):  
Spinal Cord ◽  
Evoked Potentials ◽  
Motor System ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Dorsal Column ◽  
Content Type ◽  
Dorsal Columns ◽  
Evoked Potential Monitoring ◽  
Potential Monitoring

✓ There is a need to monitor the motor system, but it has a different blood supply and a different location in the spinal cord from those measured by traditional somatosensory evoked potential monitoring. This paper reports a motor evoked potential monitoring system that uses direct spinal cord stimulation overlying the areas of the motor tract in the cord. In nine cats, evoked potentials were recorded from the dura, which gave a much faster main signal component than the traditional dorsal column evoked potentials, which were also recorded. This 100-m/sec signal was not affected by sectioning of the dorsal columns, which was verified histologically. This mode of monitoring the motor system can be used during surgery. It may also provide a better evaluation of patients after spinal cord trauma.

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. .

Dorsal root entry zone lesions for intractable pain after trauma to the conus medullaris and cauda equina

1995 ◽  
Vol 82 (1) ◽  
pp. 28-34 ◽  
Author(s):  
John H. Sampson ◽  
Robert E. Cashman ◽  
Blaine S. Nashold ◽  
Allan H. Friedman
Keyword(s):  
Dorsal Root ◽  
Cauda Equina ◽  
Conus Medullaris ◽  
Intractable Pain ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Relieve Pain ◽  
Fine Print

✓ This review was undertaken to determine the efficacy of using dorsal root entry zone (DREZ) lesions to treat intractable pain caused by trauma to the conus medullaris and cauda equina. Traumatic lesions of this area are unique in that both the spinal cord and the peripheral nerve roots are injured. Although DREZ lesions have been shown to relieve pain of spinal cord origin in many patients, they have been shown not to relieve pain of peripheral nerve origin. Therefore, 39 patients with trauma to the conus medullaris and cauda equina who underwent DREZ lesioning for intractable pain were reviewed retrospectively. The results of this review demonstrate the efficacy of DREZ lesions in these patients. At a mean follow-up period of 3.0 years, 54% of patients were pain-free without medications, and 20% required only nonnarcotic analgesic drugs for pain that no longer interfered with their daily activities. Better outcomes were noted in patients with an incomplete neurological deficit, with pain having an “electrical” character, and with injuries due to blunt trauma. Operative complications included weakness (four patients), bladder or sexual dysfunction (three), cerebrospinal fluid leak (two), and wound infection (two), but overall, 79.5% of patients (31 of 39) were without serious complications. Complications were limited to patients with prior tissue damage at the surgical exploration site and were most prevalent in patients who underwent bilateral DREZ lesions. In conclusion, this preliminary report suggests that DREZ lesions may be useful in combating intractable pain from traumatic injuries to the conus medullaris and cauda equina, with some risk to neurological function that may be acceptable in this group of patients.

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