Dorsal Root Entry Zone Lesioning: Systematic Review

Introduction Dorsal root entry zone (DREZ) leasioning (DREZ-otomy) is considered an effective treatment for chronic pain due to spinal cord injuries, brachial and lumbosacral plexus injuries, postherpetic neuralgia, spasticity, and other conditions. The objective of the technique is to cause a selective destruction of the afferent pain fibers located in the dorsal region of the spinal cord. Objective To identify and review the effectiveness and the main aspects related to DREZ-otomy, as well as the etiologies that can be treated with it. Methods The PubMed, MEDLINE and LILACS databases were used as bases for this systematic review, having the impact factor as the selection criteria. The 23 selected publications, totalizing 1,099 patients, were organized in a table for systematic analysis. Results Satisfactory pain control was observed in 70.1% of the cases, with the best results being found in patients with brachial/lumbosacral plexus injury (70.8%) and the worst, in patients with trigeminal pain (40% to 67%). Discussion Most of the published articles observed excellent results in the control of chronic pain, especially in cases of plexus injuries. Complications are rare, and can be minimized with the use of new technologies for intraoperative monitoring and imaging. Conclusion DREZ-otomy can be considered a great alternative for the treatment of chronic pain, especially in patients who do not tolerate the side effects of the medications used in the clinical management or have refractory pain.

Internal Neurolysis (Nerve Combing) for Trigeminal Neuralgia without Neurovascular Compression

Objective The aim of the present study was to describe and evaluate the initial and the long-term clinical outcome of internal neurolysis (IN) for trigeminal neuralgia (TN) without neurovascular compression (NVC). Methods A total of 170 patients diagnosed with TN were treated by posterior fossa exploration, during the period between April 2012 and October 2019. The patients were divided into two groups: Group A (50 patients)was treated by IN and Group B (120 patients) received microvascular decompression (MVD). Surgical outcomes and postoperative complications were compared between the two groups. Pain intensity was assessed by the Barrow Neurological Institute (BNI) pain intensity score and BNI facial numbness score. Pain recurrence was statistically evaluated with Kaplan-Meier analysis. Results Pain was completely relieved in 44 patients (88%) who underwent IN (group A); 3 (6%) experienced occasional pain but did not require medication (BNI 2). In group B, 113 (94%) experienced immediate pain relief after MVD. The median duration of follow-ups was 4 years (6 months to 7.5 years). In Group A, there was a meantime recurrence of 27 months in 3 patients (6%). The recurrence in Group B was of 5.8% during the follow-up period. There were no statistically significant differences in the surgical outcomes between the two groups. All patients with IN experienced some degree of numbness, 88% of the cases resolved in 6 months, on average. Conclusion Internal neurolysis is an effective, safe and durable treatment option for trigeminal neuralgia when NVC is absent.

Volume Gain of Brainstem on Medication-Overuse Headache Using Voxel-Based Morphometry / 中华医学杂志(英文版)

<p><b>Background</b>Histopathology identified the anatomical and molecular abnormalities of brainstem nuclei in migraine patients. However, the exact whole brainstem structural changes in vivo have not yet been identified in medication-overuse headache (MOH) transformed from migraine. The aim of this study was to investigate the regional volume changes over the whole brainstem in the MOH patients using voxel-based morphometry (VBM) in vivo.</p><p><b>Methods</b>High-resolution three-dimensional structural images were obtained using a 3.0-Tesla magnetic resonance system from 36 MOH patients and 32 normal controls (NCs) who were consecutively recruited from the International Headache Center, Chinese People's Liberation Army General Hospital, from March 2013 to June 2016. VBM was used to assess the brainstem structural alteration in the MOH patients, and voxel-wise correlation was performed to evaluate the relationship with the clinical characteristics.</p><p><b>Results</b>The brainstem region with increased volume located in the left ventrolateral periaqueductal gray (MNI coordinate: -1, -33, -8), ventral tegmental area (MNI coordinate: 0, -22, -12), bilateral substantia nigra (MNI coordinate: -8, -16, -12, 9, -16, -12), and trigeminal root entry zone (MNI coordinate: -19, -29, -31; 19, -32, -29) in MOH patients compared with NCs. The headache visual analog scale score was positively related with the left rostral ventromedial medulla (RVM) (MNI coordinate: -1, -37, -56; cluster size: 20; r = 0.602) in the MOH patients.</p><p><b>Conclusions</b>The regional volume gain of brainstem could underlie the neuromechanism of impaired ascending and descending pathway in the MOH patients, and the left RVM volume alteration could imply the impaired tolerance of nociceptive pain input and could be used to assess the headache disability in the MOH patients.</p>

Surgical Anatomy Of Dorsal Root Entry Zone of Cervical Spinal Nerves – Cadaveric Study.

Background: The main purpose of this study is to determine the detailed morphometric data of Dorsal Root Entry Zone (DREZ) of cervical spinal nerves. This knowledge is necessary for diagnosis, treatment and surgical management of pain due to many conditions like brachial plexus avulsion injury, post-herpetic neuralgia, phantom pain and cancer pain involved in cervical myelo-radiculopathy. There are fewer studies reported in this field of DREZ. Materials and Methods: Twenty five adult formalin fixed cadavers are taken for this study. Conventional Spinal cord dissection is followed as per Cunningham’s Dissection Mannual. Findings: The parameters included are Number of dorsal rootlets, Longitudinal Length of DREZ, Distance between two successive DREZ, Length of dorsal rootlets, Distance between right and left DREZ, Distance between DREZ and Ligamentum denticulatum, Cranial angles of Superior & inferior rootlets. Results: Results were noted for all the parameters and are compared with the previous studies. The significant observations are obtained. Conclusion: Surgical anatomy of Dorsal Root Entry Zone (DREZ) of cervical spinal nerves will be useful for the neurosurgeons doing Drezotomy procedure, in which the nociceptive fibres alone are specifically severed with preservation of other sensations.

Sensory Axon Regeneration: A Review from an in vivo Imaging Perspective

Injured primary sensory axons fail to regenerate into the spinal cord, leading to chronic pain and permanent sensory loss. Re-entry is prevented at the dorsal root entry zone (DREZ), the CNS-PNS interface. Why axons stop or turn around at the DREZ has generally been attributed to growth-repellent molecules associated with astrocytes and oligodendrocytes/myelin. The available evidence challenges the contention that these inhibitory molecules are the critical determinant of regeneration failure. Recent imaging studies that directly monitored axons arriving at the DREZ in living animals raise the intriguing possibility that axons stop primarily because they are stabilized by forming presynaptic terminals on non-neuronal cells that are neither astrocytes nor oligodendrocytes. These observations revitalized the idea raised many years ago but virtually forgotten, that axons stop by forming synapses at the DREZ.

Dorsal root entry zone incision for pain induced by brachial plexus injury: an analysis of curative effect and complications / 中华创伤杂志

Objective To evaluate the efficacy and safety of dorsal root entry zone (DREZ) incision for pain induced by brachial plexus injury. Methods A cohort study was performed in 41 consecutive patients with pain induced by brachial plexus injury treated with DREZ incision from July 2005 to December 2007. Of all, 19 patients were amputated and had phantom limb sensation. Oral pain relief (0%-100%) and complications were followed up by one professional doctor. Oral pain relief rate ≥50% was considered satisfactory outcome. Results The proportion of patients with satisfactory pain relief was 90% (37/41), 81% (30/37), 77% (24/31) and 70% (16/23) at 2 weeks, 3 months, 6 months and last follow-up (over one year) after surgery. At last follow-up, 15 out of 16 patients with over 10 years of pain duration got satisfactory pain relief; while only 16 out of 25 patients with less than 10 years of pain duration got satisfactory pain relief (x2 =4.682, P =0.030). In 16 amputees who were followed up for more than three months, seven patients with alteration of phantom limb sensation got satisfactory pain relief, while only four out of nine patients without alteration of phantom limb sensation got satisfactory pain relief. Among 37 patients followed up for more than three months, severe neurological defects were found in three patients including one with mild motor disturbance in the ipsilateral lower limb and two with severe sensory disturbance in the ipsilateral lower limb. Conclusions DREZ incisions are effective and safe neurosurgical procedure for relieving pain induced by brachial plexus injury. The possible predictive factors of better outcome are the long preoperative pain duration and postoperative phantom limb sensation among amputees.

Clinical Results of Radiofrequency Dorsal Root Entry Zone Coagulation for Paraplegic Pain

OBJECTIVE: Dorsal root entry zone(DREZ) operation has been the most common surgical treatment for paraplegic pain in the past, but the results differ according to the patients. In this study, we attempt to analyze the results from the patients by the different patterns of the pain before the surgery. METHODS: A total of twelve paraplegic patients have undergone a total of thirteen radiofrequency DREZ coagulation procedures between April 1994, and March 2003. The patients were divided depending on patients' subjective description on the character, frequency, and range of pain. RESULTS: The patients were divided into the two groups, postoperatively: improvement of more than 75% of pain was defined as treatment success, and any level less than 75% of improvement was defined as treatment failure. Eight of the ten mechanical pain group cases were regarded as treatment success, and remaining two cases with thermal type of pain as treatment failure. Also, one case with combined pain failed to obtain any favorable outcome. Intermittent pain group (6 of 7 cases), continuous pain group (2 of 6 cases), and localized pain group (7 of 11 cases) showed treatment success, respectively. However, diffuse pain group (1 of 2 cases) resulted in poor outcome. CONCLUSION: Radiofrequency DREZ coagulation is more effective in managing intermittent and/or mechanical pain than continuous and/or thermal pain in the paraplegic patients following spinal cord injury.

Nucleus Caudalis DREZ Lesioning for Intractable Pain due to Invasive Sarcoma in Skull Base: Case Report

We present a case of nucleus caudalis DREZ operation for medically refractory facial pain due to invasive sarcoma in skull base. The patient showed excellent pain relief immediately after the operation. Until 5 month later, the pain was less than before surgery. At the point of view of pain characteristics and distribution, it was considered the trigemino-vago-glossopharyngeal neuralgia. It is suggested that the nucleus caudalis DREZ operation is effective in treating medically refractory facial pain due to invasive sarcoma in skull base.

A Case of Vestibular and Facial Nerve Root Entry Zone Infarction in AICA Territory Presenting with Vertigo Which Mimics Labyrinthine Lesion

Vertigo mimicking labyrinthine lesions may have resulted from ischemic insult to the inner ear or the vestibular nerve and nucleus in the AICA infarction syndrome. A 56-year-old female was admitted to the emergency room with vertigo and hearing loss in right ear. On neurological examination, she had left beating jerky torsional and horizontal nystagmus with falling and past pointing to right side. Brain magnetic resonance images showed high signal intensity in anterolateral portion of inferior pons on T2- weighted images. Severe right facial palsy of peripheral type developed 24 hours after admission. Audiometry and electronystagmography documented absent auditory and vestibular function on the affected side. We argue that vertigo of the acute infarction in AICA territory can be involved the eight and seventh nerve root entry zoon and mimic labyrinthine lesions

Effect of Radiofrequency Dorsal Root Entry Zone Lesion for Neuropathic Intractable Pain

OBJECTIVE: The authors report a retrospective analysis of the clinical effect of dorsal root entry zone (DREZ) lesioning for neuropathic intractable pain. METHODS: Fourteen patients who underwent dorsal root entry zone lesioning for various types of pain between September 1995 and August 2001 were evaluated retrospectively. Eleven male and three female patients whose ages ranging from 35 to 70 were studied. According to causes of intractable pain, patients were divided into paraplegic pain(7 patients), peripheral nerve injury pain(3), cancer pain(3), phantom limb pain(1) and root avulsion pain(1). Other preoperative pain managements showed no benificial effects. The changes in painful symtoms were closely observed during follow up period. The mean follow period after operation was 32.4 months. RESULTS: Postoperatively, the decrease in level of pain was classified into four groups : excellent, good, fair, poor. Excellent represented no pain without medication : Good, pain tolerable with non-opiate medicine ; Fair, pain tolerable with opiate medicine ; Poor, pain sustained. After operation, three patients were in excellent group, eight in good, one in fair, and two in poor. Twelve patients were in medically tolerable pain group accounting for 85.7%. There were no serious operation releated side effects. CONCLUSION: DREZ lesioning, in our series, provided substantial pain relief and this may be considered an option in management of these types of intractable neuropathic pain.

Pain Relief from Dorsal Root Entry Zone(DREZ) Lesions Made with CO2 Laser in Brachial Plexus Injury Patients

Treatment of pain related to various types of deafferentation remains a neurosurgical challenge. Medical therapy and conventional surgical techniques for pain relief have not been effective due to this problem. Six patients with intractable pain following a brachial plexus injury were treated with dorsal root entry zone(DREZ) lesions. These lesions were made with CO2 laser. All patients were followed from 5 months to 5 years after surgery. Two-third of the patients were relieved of more than 50% of their preoperative pain. Post-operative neurosurgical complications were ipsilateral leg weakness and loss of proprioception in 2 cases. The laser technique is exact, makes uniform lesion, shortens the duration of the procedure, lessens cord manipulation and makes shalow penetration into the surrounding spinal cord. Dorsal root entry zone(DREZ) lesions made with CO2 laser appeared to be a satisfactory treatment for brachial plexus injury patients who have failed to respond to more conservative modes of therapy.

Dorsal Root Eentry Zone Operation for Brachial Plexus Avulsion Pain

No abstract available.

Microsurgical Structure of Conus Medullaris

To identify the corresponding cord segment for each root at the level of conus medullaris, a dissecting microscopic study was carried out on the spinal cord of 14 adult cadavers. We measured following contents:1) the longitudinal extent of the medullary segment of origin of each root:2) the distance from the lowest rootlet of the conus to the highest portion of the medullary segment of each root:3) the distance from the conus tip to the lowest portion of the medullary segment of each root:4) the morphological features of root-spinal cord juncton, intrathecal anastomoses, and others. We measured on the basis of the last rootlet ecause of no clear distinction between the conus and filum terminale. Our values showed considerable variation from one case to another. The average length of the whole lumbar and sacral segment was 50 mm and 30 mm, respectively. The S-1 root was the largest. Intrathecal intersegmental anastomoses were found in all cases examined, and usually consisted of small caliber rootlets connecting the spinal roots of adjacent segments. We emphasize the importance of microsurgical structure of conus medullaris when performing an operation of dorsal root entry zone or myelotomy for the relief or spasticity or intractable pain of lower extremities.

Trigeminal Neuralgia Caused by Epidermoid Tumor in the Cerebellopontine Angle

The authors report two cases of trigeminal neuralgia caused by epidermoid tumor in the cerebellopontine angle. The one case showed that trigeminal nerve was displaced superiorly by the tumor and was adhesed to the superior cerebellar artery. The other case showed that tumor mass encircled the facial, acoustic nerves as well as trigeminal nerve entirely and after removal of the tumor petrosal vein was found at the root entry zone of the trigeminal nerve. Interestingly these two cases were devoid of neurologic deficit. We tried microvascular decompression as well as removal of tumor and were satisfied with its result. We reviewed the literature and discussed these cases in point of mechanisms of trigeminal neuralgia.

Dorsal Root Entry Zone Lesion for Intractable Pain

Intractable pain was controlled in 5 cases using dorsal root entry zone lesions. All patients had failed to conservative therapy. Dorsal root entry zone lesions were made to include the involved dermatomes added one half of the dermatomes above and below the painful areas. Four patient noticed good pain relief with follow up period ranging from 6 to 24 months. Patient whose lesions were performed using a CO2 laser mas suffered no complicated deficit. Dorsal root entry zone lesions appeared to be a satisfactory treatment for intractable pain in patients, who have failed to respond to more conservative mode of therapy.

Treatment of Venous Origin Hemifacial Spasm by Microsurgical Decompression: Case Report

The hemifacial spasm has been proved a state of compression usually by blood vessels to the facial nerve. The vascular compression is usually obvious at operation. Since 1980 we have operated microsurgical decompression of 42 hemifacial spasm. Recently we have experienced a case in which venous running in an anterior posterior direction across the caudal aspect of the root entry zone of the facial nerve caused the spasm was coagulated and divided. After operation the patient improved and he free of facial spasm.

Dorsal Root Entry Zone Lesions for Intractable Pain Control

It is well documented that dorsal root entry zone(DREZ) lesions were good method to control intractable chronic deafferentation pain of spinal origin which was not controlled with various medical and surgical treatment. Experience with radiofrequency lesions of dorsal root entry zone in 3 of patients with post herpetic pain and 1 of patient with post amputation pain are reported. The follow-up period ranging from 3-20 months and all patients obtained satisfactory pain relief.