Dorsal root entry zone lesion, midline myelotomy and anterolateral cordotomy

Open thoracic cordotomy for intractable cancer pain: a how I do it

BACKGROUND

Some cancers of the lower extremity involve nerves and plexuses and can produce extreme drug-resistant noceptive pain. In these cases, open thoracic cordotomy can be proposed.

METHOD

This procedure involves disruption of the spinothalamic tract, which sustains nociceptive pathways. After placement in the prone position, selection of the side to be operated on (contralateral to the pain), and dura exposure, microsurgery is used to section the anterolateral spinal cord quadrant previously exposed by gently pulling on the dentate ligament.

CONCLUSION

Open thoracic cordotomy is a moderate invasive, safe, and effective option for the management of drug-resistant unilateral lower extremity cancer pain in well-selected patients.

Percutaneous Cervical Cordotomy for the Treatment of Cancer Pain: A Prospective Case Series of 52 Patients with a Long-Term Follow-Up

AIM

The aim of this study is to describe the effects of percutaneous cervical cordotomy (PCC) on pain, opioid consumption, adverse events, and satisfaction in palliative care patients with cancer pain after PCC until end of life.

METHODS

This is a prospective observational case series of 58 PCCs in 52 consecutive patients. Indication for PCC was unilateral cancer pain with a maximum numeric rating scale (NRS) of pain above 5 despite maximal conservative treatment. The PCC was fluoroscopy guided. A radiofrequency lesion was made at 95°C for 20 seconds. The pain location and pain scores, analgesic medication, the cranial and caudal borders of dermatomes hypoesthetic for pin pricks, dysesthesia, urinary retention, Horner's syndrome, muscle strength, Karnofsky performance scale (KPS) score, patient satisfaction, hospital anxiety and distress score (HADS), and RAND 36 score were evaluated at 1 day; 1 and 6 weeks; and 3, 6, 9, 12 18, and 24 months after PCC, or until death if death occurred during the follow-up period.

RESULTS

Pain relief after PCC was intense (change in median maximum NRS from 9 to 0) and persistent. Median opioid use per day was 240 mg (145 to 565 mg) before PCC and 55 mg (0 to 120 mg) after PCC. The upper and lower borders of dermatomes hypoesthetic for pin pricks were stable over time. The most common side effects were short-term (< 1 week) neck pain (28%), dysesthesia (40%), and mild loss of muscle strength (11%). Approximately 83% of the patients were satisfied or very satisfied with the results of PCC 1 week after the procedure, and this percentage remained high in the long term. There was no significant change in the KPS score, HADS, and RAND 36 score.

CONCLUSION

Percutaneous cervical cordotomy is an effective treatment for unilateral cancer pain. The reduction in pain, reduction in opioid consumption, and hypoesthetic area remain stable until death.

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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Rehabilitation of Spinal Cord Injury: WFNS Spine Committee Recommendations

Spinal cord injury (SCI) is accompanied by a significant number of complications associated with damage to the spinal cord, gross functional impairments leading to limited self-care and movement, leading to a high level of disability, social and psychological maladaptation of the patients. Besides, pain and spasticity negatively affect rehabilitation programs. This search was conducted in PubMed/MEDLINE database. All studies published in English language (n = 16,297) were considered for inclusion. Of all studies evaluating rehabilitation in SCI patients (n = 80) were included. Based on the literature review the faculty of the WFNS Spine Committee created statements covering different aspects of the contemporary rehabilitation process of the SCI patients. The prepared statements were subjected to discussions, followed by anonymous voting process by the members of the WFNS Spine Committee. As result of the diccussions and the voting process the statements were modified and published as recommendations of the WFNS Spine Committee. The care for the SCI has gone a long way from the times after the World War II when these patients were considered hopeless in terms of any functional recovery, to the contemporary comprehensive rehabilitation programs. The rehabilitation is important part of the modern comprehencive treatment of SCI patients nowadays. The current manuscript reflects different aspects of the contemporary rehabilitaton process and decision makings, which were discussed by the faculty of the WFNS Spine Committee resulting in issuing of the following recommendations.

The mammalian spinal commissural system: properties and functions

Commissural systems are essential components of motor circuits that coordinate left-right activity of the skeletomuscular system. Commissural systems are found at many levels of the neuraxis including the cortex, brainstem, and spinal cord. In this review we will discuss aspects of the mammalian spinal commissural system. We will focus on commissural interneurons, which project from one side of the cord to the other and form axonal terminations that are confined to the cord itself. Commissural interneurons form heterogeneous populations and influence a variety of spinal circuits. They can be defined according to a variety of criteria including, location in the spinal gray matter, axonal projections and targets, neurotransmitter phenotype, activation properties, and embryological origin. At present, we do not have a comprehensive classification of these cells, but it is clear that cells located within different areas of the gray matter have characteristic properties and make particular contributions to motor circuits. The contribution of commissural interneurons to locomotor function and posture is well established and briefly discussed. However, their role in other goal-orientated behaviors such as grasping, reaching, and bimanual tasks is less clear. This is partly because we only have limited information about the organization and functional properties of commissural interneurons in the cervical spinal cord of primates, including humans. In this review we shall discuss these various issues. First, we will consider the properties of commissural interneurons and subsequently examine what is known about their functions. We then discuss how they may contribute to restoration of function following spinal injury and stroke.

Ultrasound-Guided DREZotomy: Technical Note

Dorsal root entry zone (DREZ) lesioning is still used as a choice of treatment for some painful conditions as well as spasticity in selected patients. The most commonly used techniques to perform DREZotomy are the microsurgical one and DREZ radiofrequency (RF) coagulation. The technical difficulties using punctures to perform RF lesions include complications such as occurrence of lesions in the dorsal columns or in the corticospinal tract. This paper describes a new technical improvement in RF lesions at DREZ using intraoperative ultrasound (US) to optimize the lesions and to minimize the risk of complications. Using intraoperative US after laminotomy allows the surgeon to differentiate between the gray matter of the spinal cord and white matter, showing the correct entry zone, the angle to introduce the RF electrode, and the depth. Using intraoperative US to guide DREZ lesions provides real-time optimization of DREZotomy.

Neurosurgical ablative procedures for intractable cancer pain

OBJECTIVE

Cancer patients suffering from severe refractory pain may benefit from targeted ablative neurosurgical procedures aimed to disconnect pain pathways in the spinal cord or the brain. These patients often present with a plethora of medical problems requiring careful consideration before surgical interventions. The authors present their experience at an interdisciplinary clinic aimed to facilitate appropriate patient selection for neurosurgical procedures, and the outcome of these interventions.

METHODS

This study was a retrospective review of all patients who underwent neurosurgical interventions for cancer pain in the authors' hospital between March 2015 and April 2018. All patients had advanced metastatic cancer with limited life expectancy and suffered from intractable oncological pain.

RESULTS

Sixty patients underwent surgery during the study period. Forty-three patients with localized pain underwent disconnection of the spinal pain pathways: 34 percutaneous-cervical and 5 open-thoracic cordotomies, 2 stereotactic mesencephalotomies, and 2 midline myelotomies. Thirty-nine of 42 patients (93%) who completed these procedures had excellent immediate postoperative pain relief. At 1 month the improvement was maintained in 30/36 patients (83%) available for follow-up. There was 1 case of hemiparesis.Twenty patients with diffuse pain underwent stereotactic cingulotomy. Nineteen of these patients reported substantial pain relief immediately after the operation. At 1 month good pain relief was maintained in 13/17 patients (76%) available for follow-up, and good pain relief was also found at 3 months in 7/11 patients (64%). There was no major morbidity or mortality.

CONCLUSIONS

With careful patient selection and tailoring of the appropriate procedure to the patient's pain syndrome, the authors' experience indicates that neurosurgical procedures are safe and effective in alleviating suffering in patients with intractable cancer pain.

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.

The Hemisection Approach in Large Animal Models of Spinal Cord Injury: Overview of Methods and Applications

Introduction: Translating basic science research into a safe and effective therapy for spinal cord injury (SCI) requires suitable large animal models for testing both implantable devices and biologic approaches to better approximate human anatomy and function. Hemisection lesions, routinely used for investigational purposes in small animals, are less frequently described in large animals that might be appropriate for translational studies. Size constraints of small animals (mice and rats) limits the predictability of the findings when scaled up. Our goal is to review the status of hemisection SCI in large animals across species and time to prepare for the testing of a novel intradural spinal cord stimulation device for control of spasticity in an ovine model. Methods and Results: We surveyed the literature on hemisection in quadrupeds and nonhuman primates, and catalogued the species, protocols and outcomes of the experimental work in this field. Feline, lapine, canine, simian, porcine, ovine and bovine models were the primary focal points. There is a consistent body of literature reporting use of the hemisection approach in large animals, but with differences in surgical technique depending on the goals and nature of the individual studies. While the injuries are not always consistent, the experimental variability is generally lower than that of the contusion-based approach. In general, as the body size of the animal increases, animal care requirements and the associated costs follow. In most cases, this is inversely correlated with the number of animals used in hemisection models. Conclusions: The hemisection approach to modeling SCI is straightforward compared with other methods such as the contusive impact and enables the transection of isolated ascending and descending tracts and segment specific cell bodies. This has certain advantages in models investigating post-injury axonal regrowth. However, this approach is not generally in line with the patho-physiologies encountered in SCI patients. Even so, the ability to achieve more control over the level of injury makes it a useful adjunct to contusive and ischemic approaches, and suggests a useful role in future translational studies.

Open thoracic anterolateral cordotomy for pain relief in children: report of 2 cases

Open anterolateral cordotomy is an effective treatment option for adults with intractable pain, but it has seldom been attempted in children. In the 2 previously reported cases in children, the procedure was used within 10 days of death from neoplastic disease. In this paper the authors describe 2 cases in which open cordotomy was used successfully in children outside the immediate terminal phase of disease. Both patients experienced effective analgesia with minimal adverse effects. The authors propose that consideration of cordotomy as an option for the management of intractable pain in children does not need to be delayed until death is imminent.

Thalamic Deep Brain Stimulation for Neuropathic Pain: Efficacy at Three Years' Follow-Up

OBJECT

Chronic neuropathic pain is estimated to affect 3-4.5% of the worldwide population, posing a serious burden to society. Deep Brain Stimulation (DBS) is already established for movement disorders and also used to treat some "off-label" conditions. However, DBS for the treatment of chronic, drug refractory, neuropathic pain, has shown variable outcomes with few studies performed in the last decade. Thus, this procedure has consensus approval in parts of Europe but not the USA. This study prospectively evaluated the efficacy at three years of DBS for neuropathic pain.

METHODS

Sixteen consecutive patients received 36 months post-surgical follow-up in a single-center. Six had phantom limb pain after amputation and ten deafferentation pain after brachial plexus injury, all due to traumas. To evaluate the efficacy of DBS, patient-reported outcome measures were collated before and after surgery, using a visual analog scale (VAS) score, University of Washington Neuropathic Pain Score (UWNPS), Brief Pain Inventory (BPI), and 36-Item Short-Form Health Survey (SF-36).

RESULTS

Contralateral, ventroposterolateral sensory thalamic DBS was performed in sixteen patients with chronic neuropathic pain over 29 months. A postoperative trial of externalized DBS failed in one patient with brachial plexus injury. Fifteen patients proceeded to implantation but one patient with phantom limb pain after amputation was lost for follow-up after 12 months. No surgical complications or stimulation side effects were noted. After 36 months, mean pain relief was sustained, and the median (and interquartile range) of the improvement of VAS score was 52.8% (45.4%) (p = 0.00021), UWNPS was 30.7% (49.2%) (p = 0.0590), BPI was 55.0% (32.0%) (p = 0.00737), and SF-36 was 16.3% (30.3%) (p = 0.4754).

CONCLUSIONS

DBS demonstrated efficacy at three years for chronic neuropathic pain after traumatic amputation and brachial plexus injury, with benefits sustained across all pain outcomes measures and slightly greater improvement in phantom limb pain.

Palliative CT-Guided Cordotomy for Medically Intractable Pain in Patients with Cancer

Palliative cervical cordotomy can be performed via percutaneous radiofrequency ablation of the lateral C1-2 spinothalamic tract. This rare procedure can be safe, effective, and advantageous in mitigating medically intractable unilateral extremity pain for selected patients with end-stage cancer. This report reviews the indications, techniques, risks, and potential benefits of cordotomy. We describe our recent experience treating 3 patients with CT-guided C1-2 cordotomy and provide the first characterization of spinal cord diffusion MR imaging changes associated with successful cordotomy.

Neuropathic pain after brachial plexus avulsion--central and peripheral mechanisms

REVIEW

The pain that commonly occurs after brachial plexus avulsion poses an additional burden on the quality of life of patients already impaired by motor, sensory and autonomic deficits. Evidence-based treatments for the pain associated with brachial plexus avulsion are scarce, thus frequently leaving the condition refractory to treatment with the standard methods used to manage neuropathic pain. Unfortunately, little is known about the pathophysiology of brachial plexus avulsion. Available evidence indicates that besides primary nerve root injury, central lesions related to the abrupt disconnection of nerve roots from the spinal cord may play an important role in the genesis of neuropathic pain in these patients and may explain in part its refractoriness to treatment.

CONCLUSIONS

The understanding of both central and peripheral mechanisms that contribute to the development of pain is of major importance in order to propose more effective treatments for brachial plexus avulsion-related pain. This review focuses on the current understanding about the occurrence of neuropathic pain in these patients and the role played by peripheral and central mechanisms that provides insights into its treatment. Pain after brachial plexus avulsion involves both peripheral and central components; thereby it is characterized as a mixed (central and peripheral) neuropathic pain syndrome.