Brachial Plexus Avulsion Pain Research Articles

Retrospective Study of 57 Patients Submitted to Dorsal Root Entry Zone Lesioning by Radiofrequency for Brachial Plexus Avulsion Pain

Dorsal root entry zone (DREZ) lesioning may be used to treat neuropathic pain in patients with traumatic brachial plexus injuries. The clinical outcome after surgery is variable in the medical literature. We aimed to report the surgical outcome after DREZ lesioning by radiofrequency and to analyze prognostic factors such as the presence of a spinal cord injury identified before surgery. We conducted a retrospective study that included 57 patients who had experienced traumatic brachial plexus injuries and exhibited neuropathic pain that did not respond to conservative treatment methods. They were submitted to DREZ lesioning. We defined the inclusion and exclusion criteria, collected sociodemographic and clinical characteristics, and identified and classified spinal cord lesions based on magnetic resonance imaging. We applied statistical tests to evaluate the association between pain intensity after surgery and the radiological profile and sociodemographic characteristics. Immediately after surgery, the pain outcome was considered good or excellent in 50 patients (89.28%). At the last follow-up, it was good or excellent in 39 patients (68.43%). There was no association (p > 0.05) between the pain outcome and the variables analyzed (time interval between trauma and DREZ lesioning, presence of spinal cord injury, age, the number of avulsed roots, and the type of pain) CONCLUSIONS: DREZ lesioning using radiofrequency represents a significant therapeutic approach for managing neuropathic pain after a traumatic brachial plexus injury. Importantly, we found that the presence of a spinal cord injury is not associated with the surgical outcome.

Dorsal root entry zone lesioning for brachial plexus avulsion pain: a case series.

Retrospective case series. Dorsal root entry zone (DREZ) lesioning can be performed in patients with intractable pain following brachial plexus avulsion (BPA). However, post-operative outcomes are variable and it is uncommonly used. We sought to determine the pain outcomes and complication profile of DREZ lesioning for BPA. Quaternary neurosurgical centre. All patients that had undergone DREZ lesioning for BPA pain over a 13-year period were included. Patients were assessed for outcome with regard to degree of pain relief and presence of complications. Fourteen patients were reviewed, with a median post-operative follow-up duration of 27 months (1-145 months). Of these, ten were contactable for long-term telephone review, with a median post-operative duration of 37 months (11-145 months). At earliest review post-operatively, 12 of 14 patients (86%) had some level of pain relief: complete pain relief in four patients (29%) and partial pain relief in eight patients (57%). At most recent post-operative review, ten of 14 patients (71%) reported lasting significant pain relief: four (29%) had complete pain relief, six (43%) had partial pain relief and four (29%) had insignificant pain relief. Complications were predominantly sensory, including ataxia, hypoaesthesia and dysaesthesia. Four patients (29%) reported persistent motor complications at final follow-up. DREZ lesioning is uncommonly performed. It remains a reasonable option for relief of refractory BPA pain in selected cases, though there is a significant complication rate. Future prospective studies may enable quantification of pre- and post-lesioning analgesic use, another important determinant of procedure success.

Commentary: Combined Thermocoagulation and Mechanical Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain: 2-Dimensional Operative Video.

*Department of Neurosurgery, University of Illinois at Chicago, Chicago, Illinois, USA; ‡Neurology Service, Jesse Brown Veterans Administration Medical Center, Chicago, Illinois, USA Correspondence: Konstantin V. Slavin, MD, Department of Neurosurgery, University of Illinois at Chicago, 912 South Wood St M/C 799, Chicago, IL60612, USA. Email: [email protected]

Changes in microRNA expression in the brachial plexus avulsion model of neuropathic pain.

The present study aimed to perform microRNA (miRNA/miR) expression profiling of the thalamus (T), the anterior cingulate (AC), the dorsal horn of the spinal cord (DHSC) and the blood (B) in post-complete brachial plexus avulsion (CBPA) pain model, and analyze biological functions. Neuropathic pain was induced in Sprague-Dawley rats by CBPA. Animal behavioral tests were performed to differentiate the pain and control groups. DHSC, T, AC and B tissues were collected from the two groups for miRNA array analysis. The predicted mRNA targets were investigated by Gene Ontology analysis and pathway analysis. The results revealed that in the post-CBPA pain model, there were 10 differentially expressed miRNAs revealed among 4 different tissues. A total of 4 microRNAs in the AC and 3 microRNAs in the T were shown to be significantly upregulated. The functions of the differentially expressed miRNAs in the AC and T were synergetic in the aspect of positive regulation of neuron apoptotic process, inhibition of long-term potentiation and formation of synapse plasticity. miR-30c-1-3p and its predicted genes [calcium/calmodulin dependent protein kinase IIβ (Camk2b) and protein kinase Cγ (Prkcg)] existed in the AC and T groups with significant changes in expression. There were 2 miRNAs in the DHSC and B groups, respectively, with significant downregulation. The function of the change in miRNAs in the DHSC group was opposite to that in the AC and T groups. The differentially expressed microRNAs in the B group were revealed to be negative for the regulation of cell apoptosis. In conclusion, the central nerve groups (AC and T) and the peripheral nerve group (DHSC) exhibited contrasting effects on synapse plasticity and neuron apoptosis. miR-30c-1-3p and its predicted genes (Camk2b and Prkcg) existed in the AC and T groups with significant changes in expression.

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

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). 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. 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. 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.

Intraoperative Neurophysiological Monitoring (Motor and Somatosensory Evoked Potentials) in Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion Pain

Aims: To address the feasibility and importance of intraoperative neurophysiological monitoring (IONM) in dorsal root entry zone (DREZ) lesioning for brachial plexus avulsion pain. Methods: Muscle motor evoked potential (mMEP) and somatosensory evoked potential (SSEP) were applied during DREZ lesioning for brachial plexus avulsion pain. Results: IONM of mMEPs and SSEPs was feasible for monitoring of the spinal cord during DREZ lesioning. With the exception of 3 unrecordable mMEPs in ipsilateral arms, mMEPs were preserved and referenced to look for changes according to lesioning in 6 upper extremities (66.6%) and 8 lower extremities. All 3 patients with >50% reduction in baseline mMEP amplitude after lesioning in either the ipsilateral upper or lower extremities showed postoperative ataxia and weakness of the lower extremities (100%). Only 2 out of 9 patients (22.2%) with brachial plexus avulsion pain had discernible baseline SSEPs in the ipsilateral upper extremities. One of 2 patients with discernible SSEPs in the upper extremities showed significant SSEP events during the DREZ lesioning and experienced postoperative ataxia and weakness in the legs despite the absence of a SSEP event in the lower extremities. Conclusion: Significant events on IONM were common during DREZ lesioning for brachial plexus avulsion pain and were closely related to the occurrence of postoperative neurological deficits.

Correlation of preoperative MRI with the long-term outcomes of dorsal root entry zone lesioning for brachial plexus avulsion pain.

OBJECT Lesioning of the dorsal root entry zone (DREZotomy) is an effective treatment for brachial plexus avulsion (BPA) pain. The role of preoperative assessment with MRI has been shown to be unreliable for determining affected levels; however, it may have a role in predicting pain outcomes. Here, DREZotomy outcomes are reviewed and preoperative MRI is examined as a possible prognostic factor. METHODS A retrospective review was performed of an institutional database of patients who had undergone brachial plexus DREZ procedures since 1995. Preoperative MRI was examined to assess damage to the DREZ or dorsal horn, as evidenced by avulsion of the DREZ or T2 hyperintensity within the spinal cord. Phone interviews were conducted to assess the long-term pain outcomes. RESULTS Between 1995 and 2012, 27 patients were found to have undergone cervical DREZ procedures for BPA. Of these, 15 had preoperative MR images of the cervical spine available for review. The outcomes were graded from 1 to 4 as poor (no significant relief), good (more than 50% pain relief), excellent (more than 75% pain relief), or pain free, respectively. Overall, DREZotomy was found to be a safe, efficacious, and durable procedure for relief of pain due to BPA. The initial success rate was 73%, which declined to 66% at a median follow-up time of 62.5 months. Damage to the DREZ or dorsal horn was significantly correlated with poorer outcomes (p = 0.02). The average outcomes in patients without MRI evidence of DREZ or dorsal horn damage was significantly higher than in patients with such damage (3.67 vs 1.75, t-test; p = 0.001). A longer duration of pain prior to operation was also a significant predictor of treatment success (p = 0.004). CONCLUSIONS Overall, the DREZotomy procedure has a 66% chance of achieving meaningful pain relief on long-term follow-up. Successful pain relief is associated with the lack of damage to the DREZ and dorsal horn on preoperative MRI.

Differential Efficacy of Electric Motor Cortex Stimulation and Lesioning of the Dorsal Root Entry Zone for Continuous vs Paroxysmal Pain After Brachial Plexus Avulsion

Pain after traumatic brachial plexus avulsion (BPA) has 2 distinct patterns: continuous burning pain and paroxysmal shooting pain. Lesioning of the dorsal root entry zone (DREZotomy) is more effective for paroxysmal than continuous pain. It is unknown, however, whether electric motor cortex stimulation (EMCS) has a differential effect on continuous vs paroxysmal BPA pain. To analyze the differential effect of EMCS and DREZotomy on continuous vs paroxysmal BPA pain in a series of 15 patients. Fifteen patients with intractable BPA pain underwent DREZotomy alone (n = 7), EMCS alone (n = 4), or both procedures (n = 4). Pain intensity was evaluated with the Visual Analog Scale, and separate ratings were recorded for paroxysmal and continuous pain. Pain relief was categorized as excellent (> 75% pain relief), good (50%-75%), or poor (< 50%). Favorable outcome was defined as good or better pain relief. Eight patients had EMCS; 7 were followed up for an average of 47 months. Of those 7 patients, 3 (42%) with continuous pain had favorable outcomes compared with no patients with paroxysmal pain. Eleven patients had DREZotomy; 10 were followed up for an average of 31 months. Of those 10 patients, 7 (70%) with paroxysmal pain had favorable outcomes compared with 2 (20%) with continuous pain. EMCS was ineffective for paroxysmal pain but moderately effective for continuous pain. DREZotomy was highly effective for paroxysmal pain but moderately effective for continuous pain. It may be prudent to use EMCS for residual continuous pain after DREZotomy.

High cervical spinal cord stimulation after failed dorsal root entry zone surgery for brachial plexus avulsion pain

High cervical spinal cord stimulation after failed dorsal root entry zone surgery for brachial plexus avulsion pain

High cervical spinal cord stimulation after failed dorsal root entry zone surgery for brachial plexus avulsion pain

Background Many patients had intractable pain after brachial plexus avulsion. This article describes a feasible method of high cervical SCS for a patient who failed in DREZ surgery to treat the pain. Case Description A 70-year-old man had right brachial plexus avulsion after a car accident 15 years ago. He complained of chronic spontaneous pain over his right upper limb since then. Two DREZ surgeries failed to relieve the pain. The pain was successfully controlled by high cervical SCS. Conclusion Stimulating the high cervical spinal cord is effective for treating intractable pain after brachial plexus avulsion, which the DREZ surgery failed to relieve.

434 Prediction of results of motor cortex stimulation in treatment of brachial plexus avulsion pain by transcranial magnetic stimulation

434 Prediction of results of motor cortex stimulation in treatment of brachial plexus avulsion pain by transcranial magnetic stimulation

受傷早期から硬膜外ブロックによるとう痛管理を行った腕神経叢損傷の２症例

Brachial plexus injury often causes severe chronic upper limb pain that persists for a long time. We present 2 cases in which brachial plexus avulsion pain was managed by epidural block. Brachial plexus avulsion caused by motorbike accidents elicited severe abnormal sensations in the upper limbs, where there was complete loss of motor and sensory neurological functions. There was continuous burning and intermittent cutting pain such as causalgia in the forearm of 1 patient and an oppressive sensation such as extraction of the upper arm from the shoulder in the other patient. Continuous cervical epidural blocks were applied to both patients immediately, resulting in obvious reduction in the degree of acute pain and in the induction of chronic pain in the upper limbs. This suggests that application of cervical epidural block in the early phase is an effective therapy for patients suffering brachial plexus injury for inhibiting the chronic upper limb pain. Note that should notice application of satisfactory analgesia even in emergency cases should be as fast as possible if there is a possibility that trauma will lead to chronic pain.

Computer-Assisted DREZ Microcoagulation

Our data demonstrate that approximately 23-29% of standard dorsal root entry zone (DREZ) microcoagulation procedures fail to relieve pain due to inadequate thermal lesions and that approximately 39% fail due to insufficient superior extent of lesions. The remaining failures are related to inadequate lesion placement, improper selection of patients, and, rarely, posttraumatic spinal deafferentation pain resulting from other non-DREZ mechanisms. Computer-assisted DREZ microcoagulation is a satisfactory procedure to treat intractable posttraumatic spinal deafferentation pain, brachial plexus avulsion pain, and lumbosacral nerve root avulsion pain. In all these conditions we have identified areas of abnormal focal hyperactivity in the DREZ area. Perhaps this procedure can be applied to other central pain conditions if, using this technique, abnormal focal hyperactivity is demonstrated to be present.