Dorsal Root Entry Zone Lesioning for Brachial Plexus Avulsion: A Comprehensive Literature Review

The "banana splitting DREZotomy": an atraumatic method to improve pain relief after dorsal root entry zone lesioning in brachial plexus injuries. Case series and tenets for the treatment

BACKGROUND

The treatment of neuropathic deafferentation pain due to avulsion injuries of the brachial plexus is a major problem, albeit rare, in the neurosurgical practice. The aim of the paper is to present step-by-step the main principles of a surgical upgrade of the well-known Dorsal Root Entry Zone lesioning, that we named banana splitting DREZotomy.

METHODS

A comparison is made among three groups of patients, two of which were treated following the classic techniques, while in the third no physical agent is applied to the spinal cord during surgery.

RESULTS

The patients operated on following the well-established surgical procedures showed a short-term success rate around 70%, online with the data of the ongoing literature. The results with the banana-splitting technique, instead, have been astonishing both in terms of resolution of pain, absence of true complications and of unpleasant side effects.

CONCLUSIONS

A purely dissective technical variant of the surgical procedure called DREZ lesioning has shown better results overcoming the 30% failures of all the reported series. The profound and permanent splitting of the posterior horn and the absence of any other component (heat propagation, radiofrequency, or dotted coagulation) are the major factors which may explain such outstanding results.

The failed adult traumatic brachial plexus reconstruction

Traumatic adult brachial plexus injuries typically cause immediate loss of upper limb function. Timely multidisciplinary treatment in specialized centres often results in a useful helper arm. Both the patient and the surgical team can benefit from an open discussion to set realistic expectations. Surgical reconstruction is customized for each patient, considering their injury factors and functional objectives. Optimizing pain control, adherence to procedure indications and using meticulous surgical techniques help minimize the risk of failing to meet the patient's goals. The need for potential alternative treatment(s) if the desired result is not achieved should be detailed before the initial reconstruction. This review discusses late treatment options, including tendon transfers, joint fusions, free functioning muscle transfers and prosthetics, for managing the failed primary reconstruction of the traumatic adult brachial plexus.

Concepts of Pain Management Following Nerve Injuries: Multidisciplinary Approach

Purpose

A systematic review to identify treatment approaches for the management of pain following peripheral nerve injury.

Methods

A published literature search was performed for the concepts of peripheral nerve injury and pain management with related synonyms. The strategies were created using a combination of controlled vocabulary terms and keywords and were executed in Embase.com, Ovid-Medline All, and Scopus from database inception. Database searches were completed on August 22, 2023.

Results

The initial search resulted in a total of 1,793 citations. In total, 724 duplicates were removed, leaving 1,069 unique citations remaining for analysis. This review excluded all papers that were not specific to pain following peripheral nerve injury. Case and cohort studies (n < 5) were also excluded. Thirty-two articles on pain management strategies after peripheral nerve injury remained, with years of publication ranging from 1981 to 2023. An additional four articles were identified by manual search. Of the 36 articles reviewed, 15 articles reported on the approach to the treatment of pain after a peripheral nerve injury, and the other 22 articles consisted of cohort and case series studies.

Conclusions

There is a lack of literature describing efficacy of various treatment strategies for pain following peripheral nerve injuries. Few studies provide clear, stepwise clinical guidance for practicing physicians and other health care providers on the treatment of these complicated patients.

Evaluation and Management of Shoulder Dysfunction in Cancer Survivors

Purpose of Review

Shoulder dysfunction widely affects function and quality of life of cancer survivors. This paper discusses the etiology, identification, evaluation, and management of the common shoulder impairments seen in cancer survivors, particularly those with breast cancer, head and neck cancer, and Hodgkin lymphoma.

Recent Findings

Shoulder dysfunction can be caused by a wide range of sources, often as a sequelae of cancer treatments including surgery, systemic therapy, and radiation therapy. These can change the shoulder biomechanics leading to musculoskeletal disorders such as rotator cuff disease and adhesive capsulitis. Other etiologies include neuromuscular complications, such as post-breast surgery pain syndrome and radiation fibrosis syndrome, and lymphovascular disorders such as lymphedema and axillary web syndrome. Metastatic bone disease and primary bone cancer should be considered for those with intense shoulder pain. Detailed history and physical exam, and in some cases, imaging can assist with evaluation of shoulder issues. Exercise, physical and occupation therapy are essential in managing shoulder dysfunction.

Summary

Shoulder dysfunction can limit function and quality of life for cancer survivors. It is important to consider the possible etiologies as accurate diagnosis is critical for optimal treatment.

Trends and insights review. Nerve procedures in the management of upper limb spasticity

This article reviews the recent advances or nerve-oriented surgical procedures in the treatment of the spastic upper limb. The idea to intervene on the nerve is not recent, but new trends have developed in nerve surgery over the past few years, stimulating experiments and research. Specific surgical procedures involving the nerves have been described at different levels from proximal to distal: at the cervical spinal cord and the dorsal root entry zone (rhizotomy), at the level of the roots (contralateral C7 transfer) or in the peripheral nerve, within the motor trunk (selective neurectomy) or as its branches penetrate the muscles (hyperselective neurectomy). All of these neurosurgical procedures are only effective on spasticity but do not address the other deformities, such as contractures and motor deficit. Additional procedures may have to be planned in conjunction with nerve procedures to optimize outcomes.

Dorsal root entry zone lesioning for brachial plexus avulsion - technical evolution and long-term follow-up

BACKGROUND

Brachial plexus avulsion (BPA) injuries can cause severe deafferentation pain. This has been successfully treated with dorsal root entry zone (DREZ) lesioning. Distortions in anatomy following a BPA injury can make identifying neural structures challenging. We describe a modification to the operative technique that improves the surgical view and the advanced intraoperative neuromonitoring (IONM) employed to identify DREZ. We have analysed the long-term outcomes for pain, quality of life, and complications in patients undergoing DREZ lesioning.

METHODS

This is a single-centre retrospective case series including patients who underwent DREZ lesioning with IONM for brachial plexus avulsion between 2012 and 2022. Analysed data included pre- and postoperative pain (VAS), quality of life score for chronic pain, and complications. The evolution of the surgical approach is discussed.

RESULTS

44 consecutive patients underwent a DREZ lesioning procedure with intraoperative monitoring and mapping. In these patients the mean VAS score improved from 8.9 (7-10) to 1.87 (0-6) (p < 0.0001) at the time of discharge. 31 patients were followed-up for more than 12 months with a mean duration of follow-up of 41 months and their results were as follows: the mean VAS improved from 9.0 (7-10) to 4.1 (0-9) (p < 0.0001) at the last follow-up and the mean QOL values improved from 3.7 (2-6) to 7.4 (4-10) (p < 0.0001). The long-term outcomes were 'good' in 39%, 'fair' in 29% and 'poor' in 32% of patients. 55% of the patients were able to stop or reduce pain medications.

CONCLUSIONS

Modifications of surgical technique provide better exposure of DREZ, and IONM aids in identifying DREZ in the presence of severe intra-dural changes. Long-term outcomes of DREZ lesioning indicate not only a reduction in pain but also a significant improvement in quality of life.

Anatomical damages in the spinal nerve roots and the spinal cord after brachial plexus injury: descriptive study from a cohort of consecutive patients who underwent DREZ-lesioning for pain-practical implications

BACKGROUND

Systematic descriptions of anatomical damage after brachial plexus injury (BPI) at the intradural level have been scarcely reported in detail. However, considering these damages, not only in the spinal nerve roots but also in the spinal cord itself, is crucial in determining the appropriate surgical approach to restore upper limb function and address refractory pain. Therefore, the authors present a descriptive study focusing on intradural findings observed during microsurgical DREZ-lesioning.

METHODS

This study enrolled 19 consecutive patients under the same protocol. Microsurgical observation through exposure of C4 to Th1 medullary segments allowed to describe the lesions in spinal nerve roots, meninges, and spinal cord. Electrical stimulation of the ventral roots checked the muscle responses.

RESULTS

Extensive damage was observed among the 114 explored roots (six roots per patient), with only 21 (18.4%) ventral (VR) and 17 (14.9%) dorsal (DR) roots retaining all rootlets intact. Damage distribution varied, with the most frequent impairments in C6 VRs (18 patients) and the least in Th1 VRs (14 patients), while in all the 19 patients for the C6 DRs (the most frequently impaired) and in 14 patients for Th1 DRs (the less impaired). C4 roots were found damaged in 12 patients. Total or partial avulsions affected 63.3% and 69.8% of DRs and VRs, respectively, while 15.8% and 14.0% of the 114 DRs and VRs were atrophic, maintaining muscle responses to stimulation in half of those VRs. Pseudomeningoceles were present in 11 patients but absent in 46% of avulsed roots. Adhesive arachnoiditis was noted in 12 patients, and dorsal horn parenchymal alterations in 10.

CONCLUSIONS

Knowledge of intradural lesions post-BPI helps in guiding surgical indications for repair and functional neurosurgery for pain control.

Pain in the Context of Sensory Deafferentation

Pain that accompanies deafferentation is one of the most mysterious and misunderstood medical conditions. Prevalence rates for the assorted conditions vary considerably but the most reliable estimates are greater than 50% for strokes involving the somatosensory system, brachial plexus avulsions, spinal cord injury, and limb amputation, with controversy surrounding the mechanistic contributions of deafferentation to ensuing neuropathic pain syndromes. Deafferentation pain has also been described for loss of other body parts (e.g., eyes and breasts) and may contribute to between 10% and upwards of 30% of neuropathic symptoms in peripheral neuropathies. There is no pathognomonic test or sign to identify deafferentation pain, and part of the controversy surrounding it stems from the prodigious challenges in differentiating cause and effect. For example, it is unknown whether cortical reorganization causes pain or is a byproduct of pathoanatomical changes accompanying injury, including pain. Similarly, ascertaining whether deafferentation contributes to neuropathic pain, or whether concomitant injury to nerve fibers transmitting pain and touch sensation leads to a deafferentation-like phenotype can be clinically difficult, although a detailed neurologic examination, functional imaging, and psychophysical tests may provide clues. Due in part to the concurrent morbidities, the physical, psychologic, and by extension socioeconomic costs of disorders associated with deafferentation are higher than for other chronic pain conditions. Treatment is symptom-based, with evidence supporting first-line antineuropathic medications such as gabapentinoids and antidepressants. Studies examining noninvasive neuromodulation and virtual reality have yielded mixed results.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

Tight adhesions after spinal cord stimulation observed during dorsal root entry zone lesioning for pain after spinal root avulsion: illustrative cases

BACKGROUND

Patients often experience strong shooting pains after spinal root avulsion. The efficacy of spinal cord stimulation (SCS) for this type of pain is inconsistent; however, dorsal root entry zone (DREZ) lesioning (DREZ-lesion) has often proven to be an effective treatment modality. The authors report two cases in which DREZ-lesion was performed to treat pain after spinal root avulsion after implantation of SCS, but the operations were challenging due to strong adhesions.

OBSERVATIONS

The authors present two cases of patients with pain after spinal root avulsion in whom SCS implantation was only temporarily effective. Patients complained of persistent and paroxysmal shooting pains in the upper extremities. SCS removal and DREZ-lesion were performed, but adhesions in the epidural and subdural space contacting the leads were strong, making it difficult to expose the DREZ.

LESSONS

Although adhesions around the spinal cord can be caused by trauma, the authors believe that in these cases, the adhesions could have been caused by the SCS leads. There are few previous reports confirming the efficacy of SCS in treating pain after spinal root avulsion; therefore, caution is required when considering SCS implantation.

Cervical selective nerve root injection alleviates chronic refractory pain after brachial plexus avulsion: a case report

Background

Intractable chronic pain, as well as motor, sensory, and autonomic neuropathy, significantly reduces the quality of life of brachial plexus avulsion (BPA) patients. We report the successful application of cervical selective nerve root injection (CSNRI) in a patient with BPA.

Case presentation

A 40-year-old man had been diagnosed with complete left BPA due to a motorcycle accident and underwent intercostal nerve transplantation at the age of 18 years and had been experiencing pain ever since. His pain increased after fracture of the left humerus, and he was referred to our pain management clinic. As his exacerbated pain was suspected to be due to peripheral nerve hypersensitivity, we performed repetitive ultrasound-guided CSNRI (3 mL of 1% mepivacaine of each) targeted C5 and 6 intervertebral foramina, and his symptoms gradually improved.

Conclusions

Repetitive CSNRI may help diagnose and treat BPA-associated peripheral neuropathic pain, even in patients diagnosed with BPA.

Differential Activation of pERK1/2 and c-Fos Following Injury to Different Regions of Primary Sensory Neuron

Nerve injury causes hyperexcitability of the dorsal root ganglion (DRG) and spinal dorsal horn (DH) neurons, which results in neuropathic pain. We have previously demonstrated that partial dorsal rhizotomy (PDR) produced less severe pain-like behavior than chronic constriction injury (CCI) or chronic compression of DRG (CCD) and did not enhance DRG neuronal excitability. However, the mechanisms underlying such discrepancy remain unclear. This study was designed to compare the activation of phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) in DRG and DH, and c-Fos in DH following treatments of CCI, CCD, and PDR. We confirmed that thermal hyperalgesia produced by PDR was less severe than that produced by CCI or CCD. We showed that pERK1/2 in DRG and DH was greatly activated by CCI or CCD, whereas PDR produced only transient and mild pERK1/2 activation. CCI, CCD, and PDR induced robust c-Fos expression in DH; nevertheless, c-Fos⁺ neurons following PDR were much fewer than that following CCI or CCD. Blocking retrograde axonal transport by colchicine proximal to the CCI injury site diminished thermal hyperalgesia and inhibited pERK1/2 and c-Fos activation. These findings demonstrate that less severe pain-like behavior produced by PDR than CCI or CCD attributes to less activation of pERK1/2 and c-Fos. Such neurochemical activation partially relies on retrograde axonal transport of certain “injury signals” from the peripheral injured site to DRG somata.

Success with dorsal root entry zone lesioning after a failed trial of spinal cord stimulation in a patient with pain due to brachial plexus avulsion

Pain caused by brachial plexopathy (BP) represents a challenging clinical problem with few effective therapeutic options. Here, we present a patient with severe, painful BP after a high-impact motor vehicle accident who failed conservative treatments. A trial of cervical spinal cord stimulation was completed using multiple waveforms (tonic, BurstDR, and 10 kHz) over 14 days with only 30% to 40% pain reduction. Subsequently, he underwent dorsal root entry zone lesioning with a significant decrease in his pain 1 year later. Surgical exploration revealed extensive damage and avulsion of his cervical roots that was not observed on a previous brachial plexus magnetic resonance imaging. We discuss the etiology and diagnosis of traumatic BP, possible reasons for the failed spinal cord stimulation trial, and implications for management.

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.