Laser-induced dorsal root entry zone lesions for pain control

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

Journal of Neurosurgery ◽

10.3171/jns.1995.82.4.0587 ◽

1995 ◽

Vol 82 (4) ◽

pp. 587-591 ◽

Cited By ~ 15

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.

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

Journal of Neurosurgery Spine ◽

10.3171/spi.2002.97.2.0193 ◽

2002 ◽

Vol 97 (2) ◽

pp. 193-200 ◽

Cited By ~ 26

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.

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Spinal and Nucleus Caudalis Dorsal Root Entry Zone Operations for Chronic Pain

Operative Neurosurgery ◽

10.1227/01.neu.0000317398.93218.e0 ◽

2008 ◽

Vol 62 (suppl_1) ◽

pp. ONS235-ONS244 ◽

Cited By ~ 17

Author(s):

Yucel Kanpolat ◽

Hakan Tuna ◽

Melih Bozkurt ◽

Atilla Halil Elhan

Keyword(s):

Spinal Cord ◽

Chronic Pain ◽

Dorsal Root ◽

Intractable Pain ◽

Entry Zone ◽

Dorsal Root Entry Zone ◽

Root Entry Zone ◽

Surgical Methods ◽

Cord Injury

Abstract Objective: Dorsal root entry zone (DREZ) operations came into medical practice after the demonstration of increased electrical activity in the dorsal horn of the spinal cord and brainstem in patients with deafferentation of the central nervous system after injury to these areas. The aim of the study was to describe the technique and the effectiveness of spinal DREZ and nucleus caudalis (NC) DREZ operations, which may be the treatments of choice in unique chronic pain conditions that do not respond to medical therapy or any other surgical methods. Methods: Fifty-five patients (44 spinal, 11 NC DREZ) underwent 59 (48 spinal, 11 NC DREZ) operations. There were 44 men and 11 women with a mean age of 46.4 years (range, 24–74 yr). The mean follow-up period was 72 months (range, 6 mo–20 yr). Follow-up assessments were performed with clinical examination on the first day and in the sixth and twelfth months postoperatively. Patients' pain scores and Karnofsky Performance Scale scores were also evaluated pre- and postoperatively. Results: The initial success rates for spinal and NC DREZotomy procedures were 77 and 72.5%, respectively. In the spinal DREZotomy group, mortality occurred in one patient (2.2%). There were two cases of transient muscle weakness (4.4%) and two of cerebrospinal fluid fistulae (4.4%). In the NC DREZotomy group, mortality occurred in one patient (9%). There were two cases of transient ataxia (18%) and two of transient hemiparesis (18%). Conclusion: Spinal and trigeminal NC DREZ operations are effective in the treatment of intractable pain syndromes, especially in traumatic brachial plexus avulsions, segmental pain after spinal cord injury, postherpetic neuralgia, topographically limited cancer pain, and atypical facial pain.

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Dorsal root entry zone lesions to control central pain in paraplegics

Journal of Neurosurgery ◽

10.3171/jns.1981.55.3.0414 ◽

1981 ◽

Vol 55 (3) ◽

pp. 414-419 ◽

Cited By ~ 74

Author(s):

Blaine S. Nashold ◽

Elizabeth Bullitt

Keyword(s):

Dorsal Root ◽

Central Pain ◽

Entry Zone ◽

Dorsal Root Entry Zone ◽

Content Type ◽

Root Entry Zone ◽

Cord Injury ◽

Fine Print

✓ Thirteen patients with intractable long-term pain following spinal cord injury and paraplegia were treated with dorsal root entry zone lesions placed at the level just above the transection. Pain relief of 50% or more was achieved in 11 of the 13 patients, with follow-up periods ranging from 5 to 38 months. A previous report showed that central pain from brachial plexus avulsion could be relieved by dorsal root entry zone lesions, and this technique has been extended to the central pain phenomena associated with spinal trauma and paraplegia.

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Dorsal root entry zone (DREZ) localization using direct spinal cord stimulation can improve results of the DREZ thermocoagulation procedure for intractable pain relief

Pain ◽

10.1016/j.pain.2005.03.015 ◽

2005 ◽

Vol 116 (1) ◽

pp. 159-163 ◽

Cited By ~ 18

Author(s):

Robert Tomáš ◽

Pavel Haninec

Keyword(s):

Spinal Cord ◽

Pain Relief ◽

Spinal Cord Stimulation ◽

Dorsal Root ◽

Intractable Pain ◽

Entry Zone ◽

Dorsal Root Entry Zone ◽

Root Entry Zone

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

Journal of Neurosurgery ◽

10.3171/jns.1992.77.3.0373 ◽

1992 ◽

Vol 77 (3) ◽

pp. 373-378 ◽

Cited By ~ 99

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.

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

Journal of Neurosurgery ◽

10.3171/jns.1995.82.1.0028 ◽

1995 ◽

Vol 82 (1) ◽

pp. 28-34 ◽

Cited By ~ 39

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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Spinal cord injury below-level neuropathic pain relief with dorsal root entry zone microcoagulation performed caudal to level of complete spinal cord transection

Journal of Neurosurgery Spine ◽

10.3171/2017.9.spine17373 ◽

2018 ◽

Vol 28 (6) ◽

pp. 612-620 ◽

Cited By ~ 1

Author(s):

Scott Falci ◽

Charlotte Indeck ◽

Dave Barnkow

Keyword(s):

Spinal Cord ◽

Dorsal Root ◽

Spinal Cord Transection ◽

Central Pain ◽

Entry Zone ◽

Dorsal Root Entry Zone ◽

Root Entry Zone ◽

Cord Injury ◽

Somatotopic Map ◽

Neuronal Transmission

OBJECTIVESurgically created lesions of the spinal cord dorsal root entry zone (DREZ) to relieve central pain after spinal cord injury (SCI) have historically been performed at and cephalad to, but not below, the level of SCI. This study was initiated to investigate the validity of 3 proposed concepts regarding the DREZ in SCI central pain: 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through sympathetic nervous system (SNS) pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain-generators.METHODSThree unique patients with both intractable SCI below-level central pain and complete spinal cord transection at the level of SCI were identified. All 3 patients had previously undergone surgical intervention to their spinal cords—only cephalad to the level of spinal cord transection—with either DREZ microcoagulation or cyst shunting, in failed attempts to relieve their SCI below-level central pain. Subsequent to these surgeries, DREZ lesioning of the spinal cord solely caudal to the level of complete spinal cord transection was performed using electrical intramedullary guidance. The follow-up period ranged from 1 1/2 to 11 years.RESULTSAll 3 patients in this study had complete or near-complete relief of all below-level neuropathic pain. The analyzed electrical data confirmed and enhanced a previously proposed somatotopic map of SCI below-level DREZ pain generators.CONCLUSIONSThe results of this study support the following hypotheses. 1) The spinal cord DREZ caudal to the level of SCI can be a primary generator of SCI below-level central pain. 2) Neuronal transmission from a DREZ that generates SCI below-level central pain to brain pain centers can be primarily through SNS pathways. 3) Perceived SCI below-level central pain follows a unique somatotopic map of DREZ pain generators.

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

Journal of Neurosurgery ◽

10.3171/jns.1991.74.6.0916 ◽

1991 ◽

Vol 74 (6) ◽

pp. 916-932 ◽

Cited By ~ 35

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.

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