Neurosurgical management of neuropathic pain

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

Dorsal root entry zone (DREZ) lesioning is a neurosurgical procedure that aims to relieve severe neuropathic pain in patients with brachial plexus avulsion by selectively destroying nociceptive neural structures in the posterior cervical spinal cord. Since the introduction of the procedure over 4 decades ago, the DREZ lesioning technique has undergone numerous modifications, with a variety of center- and surgeon-dependent technical differences and patient outcomes. We have reviewed the literature to discuss reported methods of DREZ lesioning and outcomes.

Predictive factors and clinical biomarkers for treatment in patients with chronic pain caused by osteoarthritis with a central sensitisation component

AIMS

The aim of this non-systematic review was to provide a practical guide for clinicians on the evidence for central sensitisation in chronic osteoarthritis (OA) pain and how this pain mechanism can be addressed in terms of clinical diagnosis, investigation and treatment.

METHODS

The authors undertook a non-systematic review of the literature including a MEDLINE search (search terms included central sensitisation, osteoarthritis, osteoarthrosis) for relevant and current clinical studies, systematic reviews and narrative reviews. Case reports, letters to the editor and similar literature sources were excluded. Information was organised to allow a pragmatic approach to the discussion of the evidence and generation of practical recommendations.

RESULTS

There is good evidence for a role of central sensitisation in chronic OA pain in a subgroup of patients. Clinically, a central sensitisation component in chronic OA pain can be suspected based on characteristic pain features and non-pain features seen in other conditions involving central sensitisation. However, there are currently no diagnostic inventories for central sensitisation specific to OA. Biomarkers may be helpful for confirming the presence of central sensitisation, especially when there is diagnostic uncertainty. Several non-pharmacological and pharmacological treatments may be effective in OA patients with central sensitisation features. Multimodal therapy may be required to achieve control of symptoms.

DISCUSSION

Clinicians should be aware of central sensitisation in patients with chronic OA pain, especially in patients presenting with severe pain with unusual features.

Spinal and Nucleus Caudalis Dorsal Root Entry Zone Lesioning for Chronic Pain: Efficacy and Outcomes

BACKGROUND

The role for nucleus caudalis (NC) and spinal dorsal root entry zone (DREZ) lesioning in the management of chronic pain emanating from increased electrical activity in the dorsal horn of the spinal cord and brainstem remains largely uncharted.

METHODS

All patients who underwent NC and spinal DREZ lesioning by a single surgeon were identified and follow-up was obtained by telephone questionnaires. Patient demographics, surgical details, outcomes, and complications were critically reviewed for all patients identified.

RESULTS

Of 83 patients identified, 53 (63.9%) were male. Indications for NC DREZ lesioning included trigeminal neuropathic pain (6), trigeminal deafferentation pain (3), glossopharyngeal or occipital neuralgia (3), post-herpetic neuralgia (3), and trauma (1); for spinal DREZ lesioning, indications included brachial plexus avulsion (20), post-herpetic neuralgia (19), spinal cord injury (11), phantom limb pain (8), pelvic pain (5), and complex regional pain syndrome (4). Pain relief was most significant among patients with trigeminal pain, traumatic brachial plexus avulsion injuries, spinal cord injury, and traumatic phantom limb pain. Mean pain reduction averaged 58.3% at a mean follow-up of 8.3 years. Complications included 3 cases of paresis, 3 cases of neuropathy/radiculopathy, 2 cases of ataxia, 3 general medical conditions (colitis, 2; atelectasis, 1), and 2 cases of persistent incisional site pain. Pain relief lasted an average of 4.3 years.

CONCLUSIONS

Spinal and NC DREZ lesioning can provide effective relief in well-selected patients with intractable chronic pain conditions arising from trigeminal pain, spinal cord injury, brachial plexus avulsions, post-herpetic neuralgia, and phantom limb pain.

Neuropathic pain post spinal cord injury part 2: systematic review of dorsal root entry zone procedure

BACKGROUND

Pharmacotherapy may not sufficiently reduce neuropathic pain in many individuals post spinal cord injury (SCI). The use of alternative therapies such as surgery may be effective in reducing neuropathic pain in these individuals. However, because of the invasive nature of surgery, it is important to examine the evidence for use of this treatment.

OBJECTIVE

The purpose of this study was to conduct a systematic review of published literature on the surgical treatment of neuropathic pain after SCI.

METHODS

MEDLINE, CINAHL, EMBASE, and PsycINFO databases were searched for articles in which surgical treatment of pain after SCI was examined. Articles were restricted to the English language. Article selection was conducted by 2 independent reviewers with the following inclusion criteria: the subjects participated in a surgical intervention for neuropathic pain; at least 50% of the subjects had an SCI; at least 3 subjects had an SCI; and a definable intervention involving the dorsal root entry zone (DREZ) procedure was used to reduce pain. Data extracted included study design, study type, subject demographics, inclusion and exclusion criteria, sample size, outcome measures, and study results. Randomized controlled trials (RCTs) were assessed for quality using the Physiotherapy Evidence Database (PEDro) assessment scale. Levels of evidence were assigned to each intervention using a modified Sackett scale.

RESULTS

Eleven studies met the inclusion criteria. One study provided level 2 evidence, and the rest provided level 4 evidence. The DREZ procedure was shown to be more effective for segmental pain than for diffuse pain after SCI. Further, individuals with conus medullaris level injury were found to have a higher level of neuropathic pain relief than those with cervical, thoracic, or cauda equina injury.

CONCLUSIONS

The studies demonstrated that the DREZ procedure may be effective in reducing segmental pain. Hence, DREZ may be important in treatment of neuropathic pain in individuals resistant to less invasive treatments. Because the studies lacked control conditions and examination of long-term effects, there is a need for larger trials with more stringent conditions.

Spinal and Nucleus Caudalis Dorsal Root Entry Zone Operations for Chronic Pain

Objective:

Dorsal root entry zone (DREZ) operations came into medical practice after the demonstration of increased electrical activity in the dorsal horn of the spinal cord and brainstem in patients with deafferentation of the central nervous system after injury to these areas. The aim of the study was to describe the technique and the effectiveness of spinal DREZ and nucleus caudalis (NC) DREZ operations, which may be the treatments of choice in unique chronic pain conditions that do not respond to medical therapy or any other surgical methods.

Methods:

Fifty-five patients (44 spinal, 11 NC DREZ) underwent 59 (48 spinal, 11 NC DREZ) operations. There were 44 men and 11 women with a mean age of 46.4 years (range, 24–74 yr). The mean follow-up period was 72 months (range, 6 mo–20 yr). Follow-up assessments were performed with clinical examination on the first day and in the sixth and twelfth months postoperatively. Patients' pain scores and Karnofsky Performance Scale scores were also evaluated pre- and postoperatively.

Results:

The initial success rates for spinal and NC DREZotomy procedures were 77 and 72.5%, respectively. In the spinal DREZotomy group, mortality occurred in one patient (2.2%). There were two cases of transient muscle weakness (4.4%) and two of cerebrospinal fluid fistulae (4.4%). In the NC DREZotomy group, mortality occurred in one patient (9%). There were two cases of transient ataxia (18%) and two of transient hemiparesis (18%).

Conclusion:

Spinal and trigeminal NC DREZ operations are effective in the treatment of intractable pain syndromes, especially in traumatic brachial plexus avulsions, segmental pain after spinal cord injury, postherpetic neuralgia, topographically limited cancer pain, and atypical facial pain.

Management of painful neuropathies

Inadequately assessed and poorly managed pain contributes both to high general medical cost and to increasing numbers of societal problems. A large determining factor of inadequate pain care is the lack of understanding about the complex nature of pain and of a rational approach to its assessment and treatment. The less than adequate assessment of neuropathic pain and its relatively poor response to typical analgesic medications are major determinants to the undertreatment of pain. Other than the important management concept of treating the underlying cause, current approaches to the treatment of pain in general, and neuropathic pain in particular, have shifted away from treatment of individual syndromes toward the identification and management of common symptoms and the mechanisms upon which such symptoms are presumed to be based. This article summarizes the features of neuropathic pain that commonly appear in most peripheral neuropathies, regardless of the mechanism of injury, and provides an approach for the selection of treatment.

[Cost-benefit evaluation of spinal cord stimulation treatment for failed-back surgery syndrome patients]

BACKGROUND AND PURPOSE

Spinal cord stimulation is a well-known treatment of rigorously selected failed-back surgery syndrome patients. Efficacy levels over 50% of pain relief have been reported in long-term studies. The objective of this multicenter prospective evaluation was to analyze the cost to benefit ratio of spinal cord stimulation treatment for failed back surgery syndrome patients.

METHODS

Nine hospitals (pain evaluation and treatment centers) were involved in the study. Forty-three patients were selected and implanted between January 1999 and January 2000. For each patient, pre- and post-operative evaluations (6, 12 and 24 months after implantation) were performed to assess pain relief and economical impact on pain treatment costs.

RESULTS

After 24 months, mean 60% pain relief was achieved as assessed with the neuropathic pain score using a Visual Analog Scale (success rate=70%), whereas low-back pain was moderately reduced (29%). The Oswestry Disability questionnaire score was improved by a mean 39%. Costs of pain treatment (medication, consultation, other) are reduced by a mean 64% (1705 Euro) per patient per year.

CONCLUSIONS

This study confirms a clear analgesic effect on neuropathic sciatalgia, and moderate attenuation of low-back pain. One particular interest of this study is the medico-economic prospective evaluation showing that the initial cost of the implanted device is compensated by a significant, early, and stable reduction in the cost of associated pain therapies.

Diagnosis and treatment of neuropathic pain

Currently, no consensus on the optimal management of neuropathic pain exists and practices vary greatly worldwide. Possible explanations for this include difficulties in developing agreed diagnostic protocols and the coexistence of neuropathic, nociceptive and, occasionally, idiopathic pain in the same patient. Also, neuropathic pain has historically been classified according to its etiology (e.g., painful diabetic neuropathy, trigeminal neuralgia, spinal cord injury) without regard for the presumed mechanism(s) underlying the specific symptoms. A combined etiologic/mechanistic classification might improve neuropathic pain management. The treatment of neuropathic pain is largely empirical, often relying heavily on data from small, generally poorly-designed clinical trials or anecdotal evidence. Consequently, diverse treatments are used, including non-invasive drug therapies (antidepressants, antiepileptic drugs and membrane stabilizing drugs), invasive therapies (nerve blocks, ablative surgery), and alternative therapies (e.g., acupuncture). This article reviews the current and historical practices in the diagnosis and treatment of neuropathic pain, and focuses on the USA, Europe and Japan.