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.

The expression of deafferentation dysesthesias reduced by dorsal root entry zone lesions in the rat

1993 ◽  
Vol 78 (4) ◽  
pp. 598-602 ◽  
Author(s):  
Eugene Rossitch ◽  
M. Abdulhak ◽  
Janice Ovelmen-Levitt ◽  
M. Levitt ◽  
Blaine S. Nashold
Keyword(s):  
Dorsal Horn ◽  
Dorsal Root ◽  
Close Association ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Self Mutilation ◽  
Combined Lesions ◽  
Fine Print

✓ Extensive longitudinal lesions of the dorsal root entry zone (DREZ) are effective in relieving some chronic deafferentation pain in humans. A deafferentation syndrome follows C5—T2 dorsal root ganglionectomies in rats. The syndrome consists of biting and scratching the completely and partially denervated limb areas, respectively. This study examines the effect of DREZ lesions on the deafferentation syndrome in the rat. Of 37 rats, 24 underwent C5—T2 ganglionectomies only, five received C4—T3 micromechanical DREZ lesions only, and eight underwent ganglionectomies plus simultaneous DREZ lesions. The animals were observed for 45 days postoperatively. Histological analysis of the spinal cord lesions was performed. All rats with ganglionectomies alone exhibited the deafferentation syndrome; however, no rats with DREZ lesions alone showed this feature. Only 25% of rats with combined ganglionectomies and DREZ lesions exhibited the deafferentation syndrome in the first 30 days, whereas 80% of the animals with ganglionectomies only did so. Although 75% of the animals with combined lesions eventually bit the insensitive forepaw, this behavior was significantly attenuated: the day of onset was delayed and the extent of self-mutilation was reduced. Postmortem histological examination of the DREZ lesions indicated a close association between the completeness of the dorsal horn destruction and the reduction or prevention of self-mutilation. These data support the validity of the animal model and also the hypothesis stating that the deafferentation syndrome results from abnormal spontaneous neural activity in the dorsal horn. Moreover, the variability of the histological findings in these experiments stresses the importance of making contiguous and complete dorsal horn lesions in human DREZ surgery.

Microsurgical lesioning in the dorsal root entry zone for pain due to brachial plexus avulsion: a prospective series of 55 patients

2005 ◽  
Vol 102 (6) ◽  
pp. 1018-1028 ◽  
Author(s):  
Marc P. Sindou ◽  
Eric Blondet ◽  
Evelyne Emery ◽  
Patrick Mertens
Keyword(s):  
Brachial Plexus ◽  
Dorsal Horn ◽  
Dorsal Root ◽  
Activity Level ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Brachial Plexus Avulsion ◽  
Root Entry Zone ◽  
Fine Print

Object. Most patients with preganglionic lesions after brachial plexus injuries suffer pain that is hard to control through medication or neuromodulation. Lesioning in the dorsal root entry zone (DREZ) is undeniably effective. Fifty-five patients who had undergone the so-called microsurgical DREZotomy (MDT) procedure were studied with the two following objectives: 1) to describe the anatomical lesions observed during MDT in correlation with sensory deficits and pain features; and 2) to analyze the results in the 44 patients who were followed for more than 1 year (mean 6 years). Methods. The observed lesions were severe: 79.6% of ventral and 78.2% of dorsal roots from C5—T1 were impaired. Damage extended to all five roots in 42% of patients. Strong arachnoiditis was present in 38.2%, pseudomeningoceles in 31%, spinal cord distortion and/or atrophy in 49%, and abundant gliotic tissue and/or microcavitations within the dorsal horn at the avulsed segments in 36.4% of cases. Sensory deficit corresponded to the entire territory of the dorsal root lesions in 52% of patients, but was larger in 30% most certainly due to the associated extrarachidian lesions. At the last evaluation after MDT, 66% of patients showed excellent (total relief without medication) or good (total relief with medication) pain relief and 71% experienced an improvement in activity level. Conclusions. Apart from other indications not addressed in this article, MDT can be performed to treat refractory pain due to brachial plexus avulsions. The long-term efficacy of this procedure strongly indicates that pain after brachial plexus avulsion originates from the deafferented (and gliotic) dorsal horn.

Microdialysis study of amino acid neurotransmitters in the spinal dorsal horn of patients undergoing microsurgical dorsal root entry zone lesioning

2001 ◽  
Vol 94 (1) ◽  
pp. 165-173 ◽  
Author(s):  
Patrick Mertens ◽  
Chantal Ghaemmaghami ◽  
Lionel Bert ◽  
Armand Perret-Liaudet ◽  
Marc Guenot ◽  
...  
Keyword(s):  
Dorsal Horn ◽  
Dorsal Root ◽  
Spinal Dorsal Horn ◽  
Extracellular Fluid ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Spinal Dorsal ◽  
Root Entry Zone ◽  
Fine Print

✓ The aim of this study was to develop, for the first time in the human spinal dorsal horn (DH), an in vivo method for the study of amino acids (AAs). A microdialysis technique was used to sample AAs in the extracellular fluid of the DH apex in eight patients in whom surgery in the dorsal root entry zone (DREZ) was performed. Before making microsurgical lesions, specific concentric-type microdialysis probes were implanted over a 60-minute period in the DREZ and directed to the DH apex (10 implantations). The AA concentrations in the dialysates were determined using high-performance liquid chromatography with fluorescence detection. The concentrations of excitatory AAs (glutamate and aspartate) and inhibitory AAs (γ-aminobutyric acid and glycine) decreased and were stabilized by 45 minutes after probe implantation, whereas the levels of nonneurotransmitter AAs (alanine and threonine) were not stabilized at 60 minutes. The ability of the probe to track the changes of extracellular AAs was demonstrated. Neither intra- nor postoperative microdialysis-related complications were observed (with a follow up of 18 months). The present study demonstrates that microdialysis can be performed safely in the human DH during DREZ lesioning. Despite technical and analytical limitations related to the intraoperative conditions, this technique offers new possibilities for clinical research on neurotransmitters involved in some relevant pathological states, especially in chronic pain and spasticity.

Clinical and electrophysiological expression of deafferentation pain alleviated by dorsal root entry zone lesions in rats

2002 ◽  
Vol 97 (6) ◽  
pp. 1402-1409 ◽  
Author(s):  
Marc Guenot ◽  
Jean Bullier ◽  
Marc Sindou
Keyword(s):  
Brachial Plexus ◽  
Dorsal Horn ◽  
Dorsal Root ◽  
Clinical Signs ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Healthy Side ◽  
Fine Print

Object. The aims of this study were to construct an animal model of deafferentation of the spinal cord by brachial plexus avulsion and to analyze the effects of subsequent dorsal root entry zone (DREZ) lesions in this model. To this end, the authors measured the clinical and electrophysiological effects of total deafferentation of the cervical dorsal horn in rats and evaluated the clinical efficacy of cervical DREZ lesioning. Methods. Forty-three Sprague—Dawley rats were subjected to total deafferentation of the right cervical dorsal horn by performing a posterior rhizotomy from C-5 to T-1. The clinical effects of this deafferentation, namely self-directed mutilations consisting of scraping and/or ulceration of the forelimb skin or even autotomy of some forelimb digits, were then evaluated. As soon as some of these clinical signs of pain appeared, the authors performed a microsurgical DREZ rhizotomy ([MDR], microincision along the deafferented DREZ and dorsal horn). Before and after MDR, single-unit recordings were obtained in the deafferented dorsal horn and in the contralateral (healthy) side. The mean frequency of spontaneous discharge from the deafferented dorsal horn neurons was significantly higher than that from the healthy side (36.4 Hz compared with 17.9 Hz, p = 0.03). After deafferentation, 81.4% of the rats developed clinical signs corresponding to pain following posterior rhizotomy. Among these animals, scraping was observed in 85.7% of cases, ulceration (associated with edema) in 37.1%, and autotomy in 8.5%. These signs appeared a mean 5.7 weeks (range 1–12 weeks) after deafferentation. Thirteen rats benefited from an MDR; nine (69%) experienced a complete cure, that is, a total resolution of scraping or ulceration (a mean 4.6 weeks after MDR). In contrast, only one of 11 sham-operated animals showed signs of spontaneous recovery (p = 0.01). Conclusions. These results emphasize the role of the spinal dorsal horn in the genesis of deafferentation pain and suggest that dorsal horn deafferentation by cervical posterior rhizotomy in the rat provides a reliable model of chronic pain due to brachial plexus avulsion and its suppression by MDR.

Dorsal root entry zone lesions to control central pain in paraplegics

1981 ◽  
Vol 55 (3) ◽  
pp. 414-419 ◽  
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.

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.

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.

A new design of radiofrequency lesion electrodes for use in the caudalis nucleus DREZ operation

1994 ◽  
Vol 80 (6) ◽  
pp. 1116-1120 ◽  
Author(s):  
Blaine S. Nashold ◽  
Amr O. El-Naggar ◽  
Janice Ovelmen-Levitt ◽  
Muwaffak Abdul-Hak
Keyword(s):  
Dorsal Root ◽  
Facial Pain ◽  
Anatomical Study ◽  
New Right ◽  
Entry Zone ◽  
Dorsal Root Entry Zone ◽  
Content Type ◽  
Root Entry Zone ◽  
Radiofrequency Lesion ◽  
Fine Print

✓ Two new right-angled electrodes have been designed for use at the dorsal root entry zone (DREZ) of the caudalis nucleus to provide relief of chronic facial pain. The electrode design was based on an anatomical study of the human caudalis nucleus at the cervicomedullary junction. Previously, caudalis nucleus DREZ operations were often followed by ipsilateral ataxia, usually in the arm. The new electrodes have significantly reduced this complication. A group of 21 patients with varied types of chronic facial pain have been treated, with pain relief in 70%.

A new type of microelectrode for obtaining unitary recordings in the human spinal cord

1999 ◽  
Vol 91 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Marc Guenot ◽  
Jean-Michel Hupe ◽  
Patrick Mertens ◽  
Alan Ainsworth ◽  
Jean Bullier ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Entry Zone ◽  
Content Type ◽  
Human Spinal Cord ◽  
Root Entry Zone ◽  
Dorsal Horns ◽  
New Type ◽  
Conditions Of Stability ◽  
Fine Print

Object. In this paper the authors report on the conception and adjustment of a microelectrode used to obtain unitary recordings in the human spinal cord. Methods. To overcome the difficulties related to intraoperative pulsations of the spinal cord, the authors opted to use a floating microelectrode. Because the recordings are obtained most often from spontaneous activities, it is difficult, with a single microelectrode, to separate spikes from electrical artifacts that are related to the switching of devices. Consequently, the authors designed a dual microelectrode made of two tungsten-in-glass—attached microelectrodes separated by 300 µm. Because the two electrodes cannot obtain recordings in the same neuron, it is possible to distinguish unambiguously spikes (recorded on one tip) from electrical artifacts (recorded simultaneously on the two tips). The dual microelectrode is 2 cm long, with a 20-µm tip length, and 800 to 1200—Ohms impedance. This microelectrode can be implanted “free hand,” in the dorsal horn, by using a microsurgical forceps under a surgical microscope. The data analysis is performed off-line with spike sorter hardware. In the dorsal horns in 17 patients who were selected to undergo a dorsal root entry zone (DREZ) rhizotomy to treat various pathological conditions, unitary recordings were obtained using this double microelectrode. The authors recorded 57 neurons in good conditions of stability and isolation. Conclusions. The microelectrode described in this paper was successfully used to obtain recordings in neurons in more than 85% of the patients. This simplified, floating double microelectrode can therefore be considered for use in microsurgical DREZ rhizotomy to obtain unitary recordings in the human spinal dorsal horn.

Sign in / Sign up

Export Citation Format

Share Document