Treatment of neuropathic deafferentation pain using DREZ lesions; long-term results

Lumbosacral DREZotomy for oncologic pain treatment: a case-based review

PURPOSE

To present 3 cases of oncologic pain treated by DREZotomy in the pediatric population and to review the literature published about this procedure.

METHODS

The permanent literature about oncologic pain treatment in children and the applicability of DREZotomy was reviewed. Three cases treated at our institution were reviewed and presented.

RESULTS

In the pediatric population, the DREZotomy has been extensively applied for the treatment of spasticity and spasticity-related pain. Currently, there are no reports of oncologic pain treated by means of a DREZotomy in children. We presented 3 cases coursing the terminal stage of illness, presenting predominantly neuropathic, oncologic pain that were successfully managed after a DREZotomy was performed.

CONCLUSION

In well-selected patients, with a good general condition and life expectancy to withstand an open neurosurgical procedure, DREZotomy is an excellent tool to treat neuropathic oncologic pain.

Long term results of Dorsal Root Entry Zone (DREZ) lesions for the treatment of intractable pain: A systematic review of the literature on 1242 cases

BACKGROUND

Different Dorsal root entry zone (DREZ) lesion techniques have been reported as effective treatment for intractable painful conditions, though with contradictory results. Overall, good results were reported especially in specific conditions, such as pain due to brachial plexus avulsion, spinal cord injuries and oncological pain management. However, data on long term results in different clinical conditions are still missing.

OBJECTIVE

This study aims to systematically review the pertinent literature to evaluate indications, clinical outcomes, and complications of DREZ lesion (DREZotomy), in chronic pain management.

METHODS

A systematic literature review was conducted according to the PRISMA statement. Papers on DREZotomy for chronic pain in cancer, brachial plexus avulsion, spinal cord injury, post herpetic neuralgia, and phantom limb pain were considered for eligibility. For each category we further identified two sub-group according to the length of follow up: medium term and long term follow up (more than 3 years) respectively.

RESULTS

46 papers, and 1242 patients, were included in the present investigation. When considering long term results DREZotomy provided favorable clinical outcomes in brachial plexus avulsion and spinal cord injury, in 60.8% and 55.8% of the cases respectively. Conversely, the success rate was 35.3% in phantom limb pain and 28.2% in post herpetic neuralgia. A poor clinical outcome was reported in over than 25% of the patients suffering from phantom limb pain, post herpetic neuralgia and spinal cord injury. The mean complications rate was 23.58%. While BPA and SCI patients presented stable improvement over time, good outcomes among PHN and PLP groups dropped by - 46.2%; and - 14.7% at long term follow up respectively.

CONCLUSION

DREZotomy seems to be an effective treatment for chronic pain conditions, especially for brachial plexus avulsion, spinal cord injury and intractable cancer/post-radiation pain. According to the low level of evidence of the pertinent literature, further studies are strongly recommended, to better define potential benefits and limitations of this technique.

A Literature Review of Dorsal Root Entry Zone Complex (DREZC) Lesions: Integration of Translational Data for an Evolution to More Accurate Nomenclature

The purpose of this translational review was to provide evidence to support the natural evolution of the nomenclature of neuromodulatory and neuroablative radiofrequency lesions for pain management from lesions of individualized components of the linear dorsal afferent pathway to “Dorsal Root Entry Zone Complex (DREZC) lesions.” Literature review was performed to collate anatomic and procedural data and correlate these data to clinical outcomes. There is ample evidence that the individual components of the DREZC (the dorsal rami and its branches, the dorsal root ganglia, the dorsal rootlets, and the dorsal root entry zone) vary dramatically between vertebral levels and individual patients. Procedurally, fluoroscopy, the most commonly utilized technology is a 2-dimensional x-ray-based technology without the ability to accurately locate any one component of the DREZC dorsal afferent pathway, which results in clinical inaccuracies when naming each lesion. Despite the inherent anatomic variability and these procedural limitations, the expected poor clinical outcomes that might follow such nomenclature inaccuracies have not been shown to be prominent, likely because these are all lesions of the same anatomically linear sensory pathway, the DREZC, whereby a lesion in any one part of the pathway would be expected to interrupt sensory transmission of pain to all subsequent more proximal segments. Given that the common clinically available tools (fluoroscopy) are inaccurate to localize each component of the DREZC, it would be inappropriate to continue to erroneously refer to these lesions as lesions of individual components, when the more accurate “DREZC lesions” designation can be utilized. Hence, to avoid inaccuracies in nomenclature and until more accurate imaging technology is commonly utilized, the evidence herein supports the proposed change to this more sensitive and inclusive nomenclature, “DREZC lesions.”

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Bone marrow mesenchymal stem cells upregulate PI3K/AKT pathway and down-regulate NF-κB pathway by secreting glial cell-derived neurotrophic factors to regulate microglial polarization and alleviate deafferentation pain in rats

Deafferentation pain (DP), a typical neuropathic pain, occurs due to peripheral or central sensory nerve injury, which causes abnormal discharge of the upstream neurons or C fibers. Current treatment methods for DP have multiple side effects. Bone marrow mesenchymal stem cells (BMSC) have been used to treat neuropathic pain because of their ability to regulate neuroinflammation. Glial cell-derived neurotrophic factor (GDNF) is a neurotrophic mediator that exerts neuroprotective effects in neurological diseases. In this study, we investigated whether DP could be alleviated by BMSCs and the underlying mechanism. In vitro study, microglia was stimulated by lipopolysaccharide and then co-cultured with BMSC, GDNF or siRNA GDNF-BMSC. In vivo study, BMSC or siRNA GDNF-BMSC was transplanted intramedullarily on the 21st day after DP surgery. The expression of inflammatory-related factors were detected by RT-PCR and ELISA, RT-PCR,flow cytometry and immunofluorescence staining were performed to detect the expression of microglial surface markers, and Western blot was used to detect the expression levels of p-NF-kb, pPI3K, and pAKT. The pain-related behavioral changes were detected 7 days after transplantation. ELISA and RT-PCR results showed that the production of inflammatory cytokines in lipopolysaccharide-stimulated microglia and DP model plasma was downregulated, while anti-inflammatory mediators were upregulated significantly following pretreatment with BMSCs or GDNF. Flow cytometry, immunofluorescence staining, and RT-PCR results showed that BMSCs inhibited the microglial M1 phenotype and promoted the M2 phenotype by secreting GDNF. Furthermore, modulation functions of BMSCs involve inhibiting NF-κB while promoting PI3K /AKT signaling pathway activation. We found that our in vivo DP model was completely deafferent and BMSC administration clearly alleviated symptoms of DP. This function was also, at least partly, achieved by GDNF. The present studies demonstrate that BMSC can inhibit neuroinflammation by transforming microglial destructive M1 phenotype into regenerative M2 phenotype, and thus alleviate DP,likely by suppressing the NF-κB signaling pathway while promoting the PI3K/AKT signaling pathway activation through producing GDNF. The present findings are in support of the potential therapeutic application of BMSCs and the pharmaceutical application of GDNF for DP.

DREZotomy in the treatment of deafferentation pain: review of results and analysis of predictive factors for success

BACKGROUND AND OBJECTIVES

The treatment of deafferentation pain by spinal DREZotomy is a proven therapeutic option in the literature. In recent years, use of DREZotomy has been relegated to second place due to the emergence of neuromodulation therapies. The objectives of this study are to demonstrate that DREZotomy continues to be an effective and safe treatment and to analyse predictive factors for success.

PATIENTS AND METHODS

A retrospective study was conducted of all patients treated in our department with spinal DREZotomy from 1998 to 2018. Bulbar DREZotomy procedures were excluded. A visual analogue scale (VAS) and the reduction of routine medication were used as outcome variables. Demographic, clinical and operative variables were analysed as predictive factors for success.

RESULTS

A total of 27 patients (51.9% female) with a mean age of 53.7 years underwent DREZotomy. The main cause of pain was brachial plexus injury (BPI) (55.6%) followed by neoplasms (18.5%). The mean time of pain evolution was 8.4 years with a mean intensity of 8.7 according to the VAS, even though 63% of the patients had previously received neurostimulation therapy. Favourable outcome (≥50% pain reduction in the VAS) was observed in 77.8% of patients during the postoperative period and remained in 59.3% of patients after 22 months average follow-up (mean reduction of 4.9 points). This allowed for a reduction in routine analgesic treatment in 70.4% of them. DREZotomy in BPI-related pain presented a significantly higher success rate (93%) than the other pathologies (41.7%) (p=.001). No association was observed between outcome and age, gender, DREZ technique, duration of pain or previous neurostimulation therapies. There were six neurological complications, four post-operative transient neurological deficits and two permanent deficits.

CONCLUSION

Dorsal root entry zone surgery is effective and safe for treating patients with deafferentation pain, especially after brachial plexus injury. It can be considered an alternative treatment after failed neurostimulation techniques for pain control. However, its indication should be considered as the first therapeutic option after medical therapy failure due to its good long-term results.

Mechanisms of Below-Level Pain Following Spinal Cord Injury (SCI)

Mechanisms of below-level pain are discoverable as neural adaptations rostral to spinal injury. Accordingly, the strategy of investigations summarized here has been to characterize behavioral and neural responses to below-level stimulation over time following selective lesions of spinal gray and/or white matter. Assessments of human pain and the pain sensitivity of humans and laboratory animals following spinal injury have revealed common disruptions of pain processing. Interruption of the spinothalamic pathway partially deafferents nocireceptive cerebral neurons, rendering them spontaneously active and hypersensitive to remaining inputs. The spontaneous activity among these neurons is disorganized and unlikely to generate pain. However, activation of these neurons by their remaining inputs can result in pain. Also, injury to spinal gray matter results in a cascade of secondary events, including excitotoxicity, with rostral propagation of excitatory influences that contribute to chronic pain. Establishment and maintenance of below-level pain results from combined influences of injured and spared axons in the spinal white matter and injured neurons in spinal gray matter on processing of nociception by hyperexcitable cerebral neurons that are partially deafferented. A model of spinal stenosis suggests that ischemic injury to the core spinal region can generate below-level pain. Additional questions are raised about demyelination, epileptic discharge, autonomic activation, prolonged activity of C nocireceptive neurons, and thalamocortical plasticity in the generation of below-level pain. PERSPECTIVE: An understanding of mechanisms can direct therapeutic approaches to prevent development of below-level pain or arrest it following spinal cord injury. Among the possibilities covered here are surgical and other means of attenuating gray matter excitotoxicity and ascending propagation of excitatory influences from spinal lesions to thalamocortical systems involved in pain encoding and arousal.

Dorsal Root Entry Zone Lesion for Neuropathic Pain Due to Thoracolumbar Spine Fracture: Long-Term Result

OBJECTIVE

To retrospectively evaluate long-term efficacy and safety of dorsal root entry zone (DREZ) lesion for treatment of neuropathic pain within the lower extremities and perineal region after thoracolumbar spine fracture.

METHODS

Forty-two patients were treated with posterior laminectomy under general anesthesia. The DREZ regions of the spinal cord segments were ablated under a microscope. Data regarding pain relief, pain variation over time, and postoperative complications were collected. The relationship between injured spinal column segment, spinal cord, nerve root, and pain territory were analyzed retrospectively.

RESULTS

Spinal column injury segments were located between T12 and L4. Pain territories were distributed between the T11 and S5 dermatomes with varying ranges, at an average of 2-6 segments higher than the spinal cord injury segments. Pain relief rate was 100% in 21 patients (50.0%) and was over 50% in 14 patients (33.3%). Eighteen patients (42.9%) developed temporary tingling in the upper edge of the spinal cord lesion segment after surgery. Of the 4 patients with unilateral lower extremity pain, 2 developed postoperative persistent pain in the contralateral lower extremity.

CONCLUSIONS

For patients with neuropathic pain of the lower extremities and/or the perineal region after thoracolumbar spine fracture, pain within the lower extremities was mostly because of nerve root injury. Pain in the perineal region caused by L1 fracture was attributed to spinal cord injury segmental pain. Nerve root injury pain had a good prognosis after DREZ lesion; the effect of DREZ lesion for spinal cord injury segmental pain may be uncertain.

Pain inhibition through transplantation of fetal neuronal progenitors into the injured spinal cord in rats

Neuropathic pain after spinal cord injury (SCI) is a complex condition that responds poorly to usual treatments. Cell transplantation represents a promising therapy; nevertheless, the ideal cell type in terms of neurogenic potential and effectiveness against pain remains largely controversial. Here, we evaluated the ability of fetal neural stem cells (fNSC) to relieve chronic pain and, secondarily, their effects on motor recovery. Adult Wistar rats with traumatic SCI were treated, 10 days after injury, with intra-spinal injections of culture medium (sham) or fNSCs extracted from telencephalic vesicles (TV group) or the ventral medulla (VM group) of E/14 embryos. Sensory (von Frey filaments and hot plate) and motor (the Basso, Beattie, Bresnahan locomotor rating scale and inclined plane test) assessments were performed during 8 weeks. Thereafter, spinal cords were processed for immunofluorescence and transplanted cells were quantified by stereology. The results showed improvement of thermal hyperalgesia in the TV and VM groups at 4 and 5 weeks after transplantation, respectively. Moreover, mechanical allodynia improved in both the TV and VM groups at 8 weeks. No significant motor recovery was observed in the TV or VM groups compared with sham. Stereological analyses showed that ~70% of TV and VM cells differentiated into NeuN⁺ neurons, with a high proportion of enkephalinergic and GABAergic cells in the TV group and enkephalinergic and serotoninergic cells in the VM group. Our study suggests that neuronal precursors from TV and VM, once implanted into the injured spinal cord, maturate into different neuronal subtypes, mainly GABAergic, serotoninergic, and enkephalinergic, and all subtypes alleviate pain, despite no significant motor recovery. The study was approved by the Animal Ethics Committee of the Medical School of the University of São Paulo (protocol number 033/14) on March 4, 2016.

Efficacy and factors determining the outcome of dorsal root entry zone lesioning procedure (DREZotomy) in the treatment of intractable pain syndrome

BACKGROUND

Chronic pain is a disabling condition that adversely affects patient quality of life. The dorsal root entry zone lesioning procedure (DREZotomy) is a modality used to treat intractable pain caused by insults to neural structures. This study aimed to investigate the efficacy of and the factors that determine the outcome of microsurgical DREZotomy (MDT).

METHOD

All consecutive patients who underwent MDT for treatment of intractable pain during September 2008 to December 2016 were enrolled. Demographic data, clinical characteristics, intraoperative findings, and postoperative outcomes were analyzed.

RESULTS

The 40 included patients underwent MDT for relief of intractable pain caused by 27 brachial plexus injuries (BPIs), 6 spinal cord injuries, 3 neoplasms, and 4 other causes. A significant reduction in pain was observed post-MDT for both average (p < 0.001) and maximal pain (p < 0.001). Favorable outcome (≥50% pain reduction) was observed in 67.5% of patients, with the best outcome in BPI-related pain. In multivariate analysis, injury of the spinal nerve root (root avulsion or injury) was significantly associated with good average pain relief (OR, 5.8; 95% CI, 1.2-27.5; p = 0.026) and pain freedom (OR, 5.0; 95% CI, 1.12-22.30; p = 0.035). Electrical pain (OR, 6.49; 95% CI, 1.20-35.19; p = 0.030) and lower number of painful dermatomes (OR, 1.30; 95% CI, 1.01-1.67; p = 0.039) were significantly associated with good maximal pain relief.

CONCLUSIONS

MDT is an effective procedure for treatment of intractable pain in well-selected patients, particularly in cases with brachial plexus avulsion pain. Injury of the spinal nerve root (brachial plexus avulsion and cauda equina injury) was associated with good average pain relief and pain freedom, and electrical pain and lower number of painful dermatomes were associated with good maximal pain relief. The results are useful in the selection of candidates for DREZotomy and prediction of surgical outcome.

Usefulness of screening tools in the evaluation of long-term effectiveness of DREZ lesioning in the treatment of neuropathic pain after brachial plexus injury

Background

Despite high success rate of DREZ lesioning in the treatment of intractable central pain, there is still a significant incidence of patients without satisfactory post-operative effect. The aim of the study was to evaluate the long-term effect of DREZ lesioning using both a subjective assessment using a visual analog scale (VAS) to quantify residual pain and an assessment using the screening tool (painDETECT Questionnaire, PD-Q).

Methods

DREZ lesioning was performed in 52 patients from a total 441 cases with brachial plexus injury (11.8%) during a 17-year period (1995–2011). The effect of surgery was retrospectively assessed in 48 patients.

Results

A decrease in pre-operative pain by more than 75% (Group I) was achieved in 70.8% of patients and another 20.8% reported significant improvement (Group II). The surgery was unsucessful in 8.4% (Group III). We found a significant correlation between ‘improvement’ groups from both methods of assessments. Patients from Group I usually complained of residual nociceptive pain according to PD-Q, patients from Group II typically had pain of unclear origin, and all cases those in Group III suffered from neuropathic pain, Cramer’s V = .66, P < .001. Overall, 66.7% of patients had resolved neuropathic pain, 20.8% patients had more serious complaints and may also suffer from residual neuropathic pain, while 12.5% had unresolved neuropathic pain.

Conclusion

DREZ lesioning is a safe and effective method with success rates of about 90%. PD-Q scores correspond to subjective satisfaction with the surgery and it seems to be a suitable screening tool for finding patients with residual neuropathic pain after surgery.

DREZotomy in the treatment of cancer pain: a review

BACKGROUND

Cancer-related pain is a common problem that may be intractable by medical and neuromodulatory treatment. The dorsal root entry zone (DREZ) is a hyperactive focus in neuropathic pain syndromes, and DREZotomy has been used in selective cases of neuropathic cancer pain.

OBJECTIVE

The aim of this study was to describe the technique of spinal DREZotomy in the treatment of cancer pain and review the relevant published literature.

METHODS

A PubMed database search for 'DREZ', 'dorsal root entry zone' and 'cancer', and a search of the references of these manuscripts, was undertaken.

RESULTS

14 papers were identified and reviewed that described a total of 123 patients with cancer pain or radiation-induced pain who have been treated with DREZotomy. Though heterogeneous, these studies reported an overall favorable outcome in carefully selected patients with topographically limited pain syndromes.

CONCLUSION

For patients with well-localized neuropathic cancer pain intractable to medical and first-line surgical management, DREZotomy is a viable treatment option. Further prospective studies are needed to evaluate the outcomes of this procedure.