Neurostimulation for Chronic Pain: A Systematic Review of High-Quality Randomized Controlled Trials With Long-Term Follow-Up

OBJECTIVE

This study aimed to review the best evidence on the long-term efficacy of neurostimulation for chronic pain.

MATERIALS AND METHODS

We systematically reviewed PubMed, CENTRAL, and WikiStim for studies published between the inception of the data bases and July 21, 2022. Randomized controlled trials (RCTs) with a minimum of one-year follow-up that were of high methodologic quality as ascertained using the Delphi list criteria were included in the evidence synthesis. The primary outcome was long-term reduction in pain intensity, and the secondary outcomes were all other reported outcomes. Level of recommendation was graded from I to III, with level I being the highest level of recommendation.

RESULTS

Of the 7119 records screened, 24 RCTs were included in the evidence synthesis. Therapies with recommendations for their usage include pulsed radiofrequency (PRF) for postherpetic neuralgia, transcutaneous electrical nerve stimulation for trigeminal neuralgia, motor cortex stimulation for neuropathic pain and poststroke pain, deep brain stimulation for cluster headache, sphenopalatine ganglion stimulation for cluster headache, occipital nerve stimulation for migraine, peripheral nerve field stimulation for back pain, and spinal cord stimulation (SCS) for back and leg pain, nonsurgical back pain, persistent spinal pain syndrome, and painful diabetic neuropathy. Closed-loop SCS is recommended over open-loop SCS for back and leg pain. SCS is recommended over PRF for postherpetic neuralgia. Dorsal root ganglion stimulation is recommended over SCS for complex regional pain syndrome.

CONCLUSIONS

Neurostimulation is generally effective in the long term as an adjunctive treatment for chronic pain. Future studies should evaluate whether the multidisciplinary management of the physical perception of pain, affect, and social stressors is superior to their management alone.

Assessment of Prevalence and Risk Factors for Central Sensitization Related to Shoulder Osteoarthritis and Rotator Cuff Tears Using the Central Sensitization Inventory: A Cross-Sectional Study in Shoulder Surgery Patients

Shoulder disorders occasionally cause intractable pain. Central sensitization (CS) may be involved in such pain. Identifying risk factors associated with CS is crucial for effective pain control. This study aimed to determine the effects of shoulder osteoarthritis and rotator cuff tears (RCT) on CS and associated factors. This study included patients evaluated for CS using the Central Sensitization Inventory (CSI) before surgery for shoulder osteoarthritis, RCT, or cuff tear arthropathy. Patients with a CSI score of 40 or higher were defined as having CS. The relationships between glenohumeral osteoarthritis (GHOA), RCT size, and CS were statistically analyzed. Multiple regression analysis was performed to examine the factors affecting CSI scores. Subjects included 167 patients: 131 patients had RCT without GHOA, 23 had GHOA with RCT, and 13 had GHOA without RCT. The GHOA group had a significantly higher CSI score (27.5 [10.8-40.5] vs. 18.0 [10.0-27.5]) and CS prevalence (27.8% vs. 8.4%) than the RCT without GHOA group. There was no significant correlation between RCT size and CSI scores. Multiple regression analysis showed that female sex, severe pain, and long pain duration were associated with higher CSI scores. Considering the risk factors for CS might be helpful in shoulder treatment.

Perspectives on emotional memory images and the persistence of pain

Multiple influences prevent recovery from pain. Our viewpoint is that non-conscious emotional memory images (EMIs) triggers outdated stress responses contributing to the intractability of pain. In this perspectives article we explore the concept that EMIs contribute to the persistence of pain. We contend that psychophysiological "stress" responses, resulting from first-time, novel and unprecedented pernicious or adverse events form EMIs within very short time frames (split-second learning). Subsequently, these EMIs are re-triggered in daily living, "re-playing" stress responses. We postulate that EMIs continually "raise the alarm" to socio-ecological stimuli by re-triggering the HPA-axis and amplifying neural input associated with threat, fear, anxiety, and pain, creating a debilitating state of psychophysiological dis-ease. We position the EMI within a philosophical debate on the nature and locus of memory and explain how the EMI, irrespective of whether it is a "thing" or a metaphor, can create a basis of understanding for the client to grasp. We describe a therapeutic approach (Split-Second Unlearning) to "clear" EMIs and the "stickiness" of pain and help people embark on a healing journey. This involves surveillance of clients for micro-expression(s) signifying an in-the-moment stress response, representative of the presence of an EMI, and encouraging the client to become a curious observer within/of their own experience. This helps the client detach their EMI from its stress response. We contend that this occurs rapidly without the need to get bogged down in a whole-life narrative. We advocate further exploration of our EMI model of dis-ease in the context of intractable pain.

A Case Report on Spinal Neurostimulator Treatment for Painful Postsurgical Neuropathy of the Genitofemoral Nerve

Painful postsurgical neuropathy is an adverse event inherent to a wide variety of surgical treatments, so its diagnosis and specialized treatment are essential to maintaining the quality of life of the people who suffer from it. We present the case of a 31-year-old male with neuropathy of the genitofemoral nerve diagnosed by electromyography, resulting in intractable left testicular and thigh pain associated with a recent history of ipsilateral inguinal hernioplasty. After assessment by pain medicine and motor and sensory tests, a neurostimulator was placed in T8-T9 with action at the L1-L2 level, as well as a simultaneous electrode in S3, generating optimal pain relief and recovery of functionality.

A National Survey of Institutional Guidelines for the Use of Ketamine, Lidocaine, and Dexmedetomidine for Refractory Pain

Background: Although opioids are used first line for cancer pain and commonly for complex noncancer pain, there are risks associated with their use and not effective for all types of pain. There's a need to identify and develop clinical practice guidelines for nonopioids for the treatment of refractory pain. Methods: Our study collected information from national clinical practice guidelines for ketamine, lidocaine, and dexmedetomidine with the aim to identify consensus among the different practices. Results: Fifteen institutions nationally participated in the study and only nine of those institutions had guidelines and were permitted by their health system to share them. Of the institutions that participated, 44% had guidelines for ketamine and lidocaine, and only two institutions (22%) had guidelines for ketamine, lidocaine, and dexmedetomidine for refractory pain. There were variations in restriction of the level of care and prescribers, dosing, and determination of efficacy. There were trends of consensus in monitoring for side effects. Conclusion: This study serves as a starting point for a snapshot of the use of ketamine, lidocaine, and dexmedetomidine for refractory pain, but further studies and increased participation of institutions are needed to develop consensus clinical practice guidelines.

Off-label pharmacological treatment for neuropathic pain: A Delphi study by the Spanish Pain Society Neuropathic Pain Task Force

OBJECTIVES

The use of off-label pharmacotherapies for neuropathic pain (NP) is growing relating to the many unmet needs of patients. However, clinical guidelines fail to address it, and the available evidence is sparse and fragmented. We arranged a formal expert consensus to address this controversial issue and provide some guidance on judicious use.

METHODS

A two-round standard Delphi survey that involved pain clinic specialists with experience in the research and management of NP was done over an ad hoc 40-item questionnaire prepared by the authors. Consensus on each statement was defined as at least either 80% endorsement or rejection after the second round.

RESULTS

Forty-three and thirty-seven panelists participated in the first and second round, respectively. Consensus was reached in 34 out of 40 statements. Endorsed alternatives for unresponsive patients include non-gabapentinoid antiepileptics (oxcarbazepine and eslicarbazepine), venlafaxine, intravenous lidocaine (when doses can be optimized), and some vaporized cannabinoids (under appropriate surveillance). In addition, lacosamide, low-dose naltrexone, propofol, or ketamine could prove beneficial if subjected to more research. Other options were rejected, and there was controversy about the usefulness of topical preparations.

DISCUSSION

For patients who do not respond to standard NP treatments, some other viable pharmacological options can be attempted before advancing to other therapeutic stages. This may help patients who are reluctant to or have some contraindication for interventional therapies.

Ultrasound-guided percutaneous peripheral nerve stimulation for chronic refractory neuropathic pain: a unique series

During the last two decades, with the advent of recent technology, peripheral nerve stimulation has become an appealing modality at the forefront of pain management. In this case series, we document the clinical rationale and technical considerations on three of the most challenging cases, refractory to previous interventions, that were treated by our team with an ultrasound-guided percutaneous peripheral nerve stimulator targeting the musculocutaneous, bilateral greater occipital and subcostal nerves. At the 6-month follow-up, all patients experienced greater than 50% relief of baseline pain, with a near-complete resolution of pain exacerbations. Furthermore, to our knowledge, this is the first report of an ultrasound-guided percutaneous technique of a peripheral nerve stimulator targeting the musculocutaneous and subcostal nerves.

CyberKnife Radiosurgery for refractory bilateral trigeminal neuralgia. Case report

Case description: A case of a 37-year-old female patient suffering from refractory bilateral trigeminal neuralgia is presented, who underwent various interventions such as acupuncture, block therapies and even microvascular decompression without effective pain relief.

Clinical findings

Paresthesias and shooting-like twinges of pain intensity 10/10 in bilateral maxillary and mandibular branches of the trigeminal nerve, with nasal and intraoral triggers that made eating impossible, becoming increasingly severe since refractoriness to microvascular decompression and carbamazepines, triggering the twinges even during sleep, generating somnolence, depressive mood and social isolation.

Treatment and results

The patient was evaluated by an interdisciplinary neuro-oncology team, where, in accordance with the analysis of the brain magnetic resonance imaging and the patient's history, it was indicated to perform Cyberknife® radiosurgery in monofraction on the left trigeminal and subsequently treat the contralateral trigeminal. When treated with Cyberknife® radiosurgery, the patient reported absolute improvement in her pain for 2 years.

Clinical relevance

Radiosurgery by CyberKnife is not yet the first line of management in trigeminal neuralgia, however, it should be considered since several studies have managed to demonstrate an increase in the quality of life of patients and pain relief in refractory or severe cases. of said pathology.

Spinal cord stimulation for treatment of complex regional pain syndrome: a single-centre retrospective case series study

INTRODUCTION

Complex regional pain syndrome (CRPS) is a debilitating disease with limited available treatment options. Spinal cord stimulation (SCS) is a universal option that promises to improve quality of life by reducing intractable neuropathic pain. The aim of this study was to describe the effectiveness and safety of SCS as a treatment for CRPS patients.

CLINICAL RATIONALE FOR THE STUDY

SCS as an invasive method has relatively recently been introduced to CRPS therapy. We hypothesised that by assessing the effectiveness and safety of SCS, we could justify its early use in the treatment of this debilitating condition.

MATERIAL AND METHODS

CRPS is a multifactorial and disabling disorder with complex aetiopathogenesis. The primary goals of CRPS treatment include pain relief, functional restoration, and psychological stabilisation. Early intervention is needed to achieve these objectives. In this study, we performed a retrospective evaluation of clinical outcomes in seven patients with severe, intractable CRPS treated by SCS. All patients underwent implantation of a non-rechargeable prime advanced MRI implantable pulse generator (IPG) (Medtronic, Minneapolis, MN, USA) between December 2017 and December 2020 using identical surgical and intraprocedural techniques.

RESULTS

From a total of 21 patients treated with SCS over the three years in question, seven (33%) were diagnosed with severe CRPS. The duration of chronic pain ranged between two and 12 years. In six cases (86%), an electrode was implanted in the thoracic segment. Good (partial pain reduction) or very good (complete pain relief) treatment results were observed in five patients (72%). In two cases (28%), two revision surgeries were performed for wound debridement. These hardware-related complications were primarily related to erosions located over implanted IPG's.

CONCLUSIONS AND CLINICAL IMPLICATIONS

SCS is the best alternative for patients with CRPS. It should be used immediately after the failure of conservative treatment. Despite the relatively high complication rate in our series, it is the best choice for pain reduction management in this select group of patients.

Pain patterns in chronic pancreatitis: a nationwide longitudinal cohort study

OBJECTIVE

Pain in chronic pancreatitis is subdivided in a continuous or intermittent pattern, each thought to represent a different entity, requiring specific treatment. Because evidence is missing, we studied pain patterns in a prospective longitudinal nationwide study.

DESIGN

1131 patients with chronic pancreatitis (fulfilling M-ANNHEIM criteria) were included between 2011 and 2018 in 30 Dutch hospitals. Patients with continuous or intermittent pain were compared for demographics, pain characteristics, quality of life (Short-Form 36), imaging findings, disease duration and treatment. Alternation of pain pattern and associated variables were longitudinally assessed using a multivariable multinomial logistic regression model.

RESULTS

At inclusion, 589 patients (52%) had continuous pain, 231 patients (20%) had intermittent pain and 311 patients (28%) had no pain. Patients with continuous pain had more severe pain, used more opioids and neuropathic pain medication, and had a lower quality of life. There were no differences between pain patterns for morphological findings on imaging, disease duration and treatment. During a median follow-up of 47 months, 552 of 905 patients (61%) alternated at least once between pain patterns. All alternations were associated with the Visual Analogue Scale pain intensity score and surgery was only associated with the change from pain to no pain.

CONCLUSION

Continuous and intermittent pain patterns in chronic pancreatitis do not seem to be the result of distinctly different pathophysiological entities. The subjectively reported character of pain is not related to imaging findings or disease duration. Pain patterns often change over time and are merely a feature of how severity of pain is experienced.

Intravenous Ketorolac Infusion for Intractable Pleuritic Pain Secondary to Metastatic Epithelioid Hemangioendothelioma

Background: Epithelioid hemangioendothelioma (EHE) patients can experience severe pain. Nonsteroidal anti-inflammatory drugs, including ketorolac tromethamine, can effectively treat cancer-related pain, provide an opioid-sparing effect, and may be particularly effective for EHE pain. There are limited data describing prolonged (>5 days) continuous intravenous (IV) ketorolac infusion for cancer-related pain and no data on its use in EHE. Case Description: A 67-year-old woman with metastatic hepatic EHE suffered from chronic intractable pleuritic pain unresponsive to trials of nonopioid, opioid, adjuvant medications, and nonpharmacological interventions. In the hospital, continuous IV ketorolac infusion at 3.8 mg/hour (91.2 mg/day) effectively managed pain. With thorough monitoring, the patient was discharged on continuous IV ketorolac infusion at 3 mg/hour (72 mg/day). Infusion continued for 79 days without clinical or laboratory evidence of ketorolac toxicity. Conclusion: Ketorolac tromethamine as a long-term infusion is a potentially viable analgesic for patients with intractable EHE-related pain unresponsive to standard therapies.

Management of intractable pain in patients treated with hemorrhoidectomy for mixed hemorrhoids

BACKGROUND

Post-hemorrhoidectomy pain is common, usually temporary, and responsive to analgesics. However, some patients experience prolonged, intractable anal pain, which is refractory to conventional analgesics and adversely effects quality of life. We aimed to evaluate the efficacy of a combination injection containing local anesthesia and steroids for the treatment of intractable post-hemorrhoidectomy anal pain.

METHODS

This study included five patients with intractable post-hemorrhoidectomy anal pain who presented between July 2015 and November 2018. Milligan-Morgan hemorrhoidectomy (M-M) with a sclerosant injection had been performed in three patients and stapled hemorrhoidectomy (SH) along with external hemorrhoidectomy in two. For the purpose of this study, all patients received local combination injections containing ropivacaine and triamcinolone acetonide. The primary outcome was the visual analogue scale (VAS) score, and secondary outcomes included the Pittsburgh Sleep Quality Index (PSQI) score, adverse reactions, and recurrence.

RESULTS

Prior to treatment, the VAS score was 8 in one patient and 5-7 in four, and the PSQI score was ≥16 in all patients. The injection was administered once (n=4) or twice (n=1). Rapid pain resolution was achieved on the day of treatment (VAS scores 0-3), and patients reported undisturbed sleep the same night. VAS scores were 0-2 (n=4) and 1-3 (n=1), and the PQSI scores were 0-6 (n=4) and 11-15 (n=1) at the 6-month follow-up. No patient reported significant pain or adverse reaction.

CONCLUSIONS

Intractable post-hemorrhoidectomy anal pain is rare but significantly effects quality of life. While conventional analgesia may be ineffective, the local injection of anti-inflammatory and analgesic drugs may be a useful treatment strategy.

Successful application of burst spinal cord stimulation for refractory upper limb pain: a case series

Spinal cord stimulation (SCS) has been used to treat sustained pain that is intractable despite various types of treatment. However, conventional tonic waveform SCS has not shown promising outcomes for spinal cord injury (SCI) or postamputation pain. The pain signal mechanisms of burst waveforms are different to those of conventional tonic waveforms, but few reports have presented the therapeutic potential of burst waveforms for the abovementioned indications. This current case report describes two patients with refractory upper limb pain after SCI and upper limb amputation that were treated with burst waveform SCS. While the patients could not obtain sufficient therapeutic effect with conventional tonic waveforms, the burst waveforms provided better pain reduction with less discomfort. However, further studies are necessary to better clarify the mechanisms and efficacy of burst waveform SCS in patients with intractable pain.

Spinal Cord Stimulator Paddle Lead Surgery Complicated by Cerebrospinal Fluid Leak and Fistula Formation

Spinal cord stimulation (SCS) paddle leads placed via laminectomy procedures have become common as more data accumulates with regards to their clinical efficacy. In this paper, we describe a case of a 72-year-old male patient with failed back surgery syndrome (FBSS) who underwent a thoracic laminectomy for permanent paddle lead placement. He went on to develop a complication that resulted in a large cerebrospinal fluid leak with a cerebrospinal fluid fistula formation.

Medial Gamma Knife thalamotomy for intractable pain

OBJECTIVEAblative procedures are still useful in the treatment of intractable pain despite the proliferation of neuromodulation techniques. In the paper the authors present the results of Gamma Knife thalamotomy (GKT) in various pain syndromes.METHODSBetween 1996 and 2016, unilateral GKT was performed in 30 patients suffering from various severe pain syndromes in whom conservative treatment had failed. There were 20 women and 10 men in the study population, with a median age of 80 years (range 53-89 years). The pain syndromes consisted of 8 patients with classic treatment-resistant trigeminal neuralgia (TN), 6 with postherpetic TN, 5 with TN and constant pain, 1 with TN related to multiple sclerosis, 3 with trigeminal neuropathic pain, 4 with thalamic pain, 1 with phantom pain, 1 with causalgic pain, and 1 with facial pain. The median follow-up period was 24 months (range 12-180 months). Invasive procedures for pain release preceded GKT in 20 patients (microvascular decompression, glycerol rhizotomy, balloon microcompression, Gamma Knife irradiation of the trigeminal root, and radiofrequency thermolesion). The Leksell stereotactic frame, GammaPlan software, and T1- and T2-weighted sequences acquired at 1.5 T were used for localization of the targeted medial thalamus, namely the centromedian (CM) and parafascicularis (Pf) nucleus. The CM/Pf complex was localized 4-6 mm lateral to the wall of the third ventricle, 8 mm posterior to the midpoint, and 2-3 mm superior to the intercommissural line. GKT was performed using the Leksell Gamma Knife with an applied dose ranging from 145 to 150 Gy, with a single shot, 4-mm collimator. Pain relief after radiation treatment was evaluated. Decreased pain intensity to less than 50% of the previous level was considered successful.RESULTSInitial successful results were achieved in 13 (43.3%) of the patients, with complete pain relief in 1 of these patients. Relief was achieved after a median latency of 3 months (range 2-12 months). Pain recurred in 4 (31%) of 13 patients after a median latent interval of 24 months (range 22-30 months). No neurological deficits were observed.CONCLUSIONSThese results suggest that GKT in patients suffering from severe pain syndromes is a relatively successful and safe method that can be used even in severely affected patients. The only risk of GT for the patients in this study was failure of treatment, as no clinical side effects were observed.

Intravenous Lignocaine Infusion for Intractable Pain in Ewing's Sarcoma

A 23-year-old female presented to our palliative care center with Ewing's sarcoma of the humerus with lung metastases. Pain in her arm was unrelieved by nonsteroidal anti-inflammatory drugs, neuropathic medication as well as morphine. She could not tolerate any further increase in opioid dose but was so distraught due to the pain that she wanted to die. An intravenous lignocaine infusion in a dose of 2 mg/kg was given over an hour for three successive days. This successfully relieved her pain after which she was settled with her original medication. We feel that in palliative care settings, where intractable pain and tolerance to morphine are so common, intravenous lignocaine infusions could provide a safe and effective tool for pain relief.

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.

Evaluation of intrathecal drug delivery system for intractable pain in advanced malignancies: A prospective cohort study

Pain is prevalent in advanced malignancies; however, some patients cannot get adequate pain relief by conservative routes of analgesic administration or experience serious side effects related to high dose of opioids. For those who have exhausted multimodal conservative analgesic, intrathecal drug delivery is an alternative intervention for truly effective pain management. The objective of this study was to evaluate the clinical efficacy and safety of intrathecal drug delivery system (IDDS) for the treatment of intractable pain in advanced cancer patients.A prospective cohort study was performed between July 2015 and October 2016. Fifty-three patients undergoing intractable cancer-related pain or intolerable drug-related adverse effects were recruited and received IDDS therapy with a patient-controlled intrathecal analgesia pump. The assessment was conducted during admission, in titration period, and followed up monthly to death by scheduled refill visits. Pain numeric rating scale scores, comprehensive toxicity scores, quality of life scores, systemic opioid use (basal and breakthrough dose), intrathecal morphine use (basal and patient-controlled intrathecal analgesia dose), and complications were recorded to evaluate the curative effect and safety.Between baseline and all subsequent follow-ups, statistically significant decreases in pain numeric rating scale scores and comprehensive toxicity scores were verified. A statistical improvement in quality of life scores was found after starting IDDS therapy. Both basal and breakthrough doses of systemic opioid showed a significant decrease during the follow-up period. And there was a modest escalation in the intrathecal morphine dose throughout the duration of study. No infective, device-related, and catheter-related complications were observed.The findings showed that IDDS therapy allowed for rapid and highly effective pain relief with less toxicity in comparison to conservative medications. Patients with advanced malignancies would also benefit from an improvement in the life quality after the procedure. IDDS therapy represented a valuable option for intractable cancer-related pain management.

Myocardial ischaemia and cardiac pain - a mysterious relationship

Pain related to cardiac disease has been recognised for centuries. However, the precise mechanisms of angina pectoris remain bafflingly obscure. Conventional cardiological angina management concentrates on methods to improve oxygen delivery to cardiac myocytes as our understanding of cardiac muscle cells' response to hypoxia increases. In common with other chronic visceral pain syndromes, little is understood about how pain signals are generated and propagated by visceral nerves. Improved imaging and other physiological assessments have demonstrated important central nervous system (CNS) responses to myocardial ischaemia, including activation of CNS areas known to be 'key players' in chronic pain syndromes. Patients with stable angina usually have an excellent prognosis, especially if left ventricular function is preserved. Educating patients about their condition, teaching simple techniques known to help chronic pain patients and introducing targeted pain treatments specific to angina can be extremely helpful adjuncts to conventional cardiological treatments and will often bring about significant improvements in quality of life.

Using qualitative methods to access the pain experience

Qualitative methods provide us with techniques to access the pain experience of patients in ways that provide explanation for apparent contradictions and idiosyncrasies that are difficult to access. In this article, I review three such strategies and the application of qualitative research to practice: (1) the analysis of the ways participants speak about agonizing pain using narrative inquiry, (2) comparisons of childbirth pain in two cultural groups using ethnography and (3) present a qualitative theory, the Praxis Theory of Suffering. This theory provides a theoretical explanation for behaviours that presently confound the understanding of distress using the Distress Thermometer. An alternative approach, 'reading' patients' behavioural manifestations of distress, is recommended.

A case report of dexmedetomidine used to treat intractable pain and delirium in a tertiary palliative care unit

BACKGROUND

This case report describes an end-stage cancer patient with intractable neuropathic pain and delirium who was successfully managed during the last 3 weeks of her life with a continuous subcutaneous infusion of dexmedetomidine.

CASE PRESENTATION

A 55-year-old woman with locally advanced cervical cancer and uncontrolled pelvic pain was admitted to a tertiary palliative care unit for pain management. As her disease progressed, the patient's pelvic pain intensified despite treatment with methadone, gabapentin, ketamine, and hydromorphone administered by continuous subcutaneous infusion plus frequent breakthrough doses of hydromorphone and sufentanil.

CASE MANAGEMENT

A continuous subcutaneous infusion of dexmedetomidine was started and titrated to achieve pain relief.

CASE OUTCOME

The patient's pain and delirium cleared. The treatment was successful in fulfilling the patient's goal of care: not to be deeply and continuously sedated, but to be rousable and of clear mind while still having good pain control.

CONCLUSION

Dexmedetomidine is a potentially useful medication for the targeted treatment of intractable pain and delirium in the tertiary palliative care environment. Future research is required to compare dexmedetomidine infusion to standard treatment with midazolam infusion for treatment of intractable symptoms in the palliative care environment.

Anatomic considerations for spinal cord stimulation

INTRODUCTION

While generally knowledgeable about spinal cord anatomy and physiology, most interventional pain physicians do not often use this information to improve the safety and efficacy of spinal neuromodulation procedures.

METHODS

The anatomy and physiology of the spinal canal and spinal cord are reviewed and interpreted through the context of spinal neuromodulation.

RESULTS

Based upon common features of global spinal anatomy and significant regional local differences, recommendations that may impact the choice of neuromodulation procedures and the devices and approaches for administering such procedures are suggested.

CONCLUSIONS

By carefully considering differences in regional spinal anatomy and physiology, interventional pain physicians may be able to improve both the safety and efficacy of spinal neuromodulation for intractable pain.

The long-term safety and efficacy of intrathecal therapy using sufentanil in chronic intractable non-malignant pain

This report describes the long term safety and efficacy of intrathecal therapy using Sufentanil for the management of chronic intractable neuropathic pain in 12 chronic pain patients. Standardized psychological screening was used to determine treatment suitability. Evaluation data included the Visual Analog Scale (VAS), Wong-Baker Faces Scale, Brief Pain Inventory (BPI), Disability of Arm, Shoulder, and Hand (DASH), McGill Quality of Life Questionnaire, and complications (granulomas, toxicity, withdrawal, or deaths). SPSS version 18 was used for data analysis. Pre- and post- treatment BPI measures and pain scale scores showed a statistically significant difference. There were no complications directly related to drug toxicity, nor drug withdrawals, granulomas, or deaths. Intrathecal therapy with Sufentanil therapy offers a good treatment alternative for those cases that have failed both surgery and standard pain treatment. Strict patient selection based on psychological screening, control of co-morbidities, a proper pain management may contribute to successful outcome.

Occipital nerve block prior to occipital nerve stimulation for refractory chronic migraine and chronic cluster headache: myth or prediction?

BACKGROUND

Occipital nerve stimulation (ONS) results in beneficial outcomes, with marked pain relief, in otherwise intractable chronic migraine (CM) and chronic cluster headache (CCH). Some studies have reported that a positive response to occipital nerve block (ONB) administered prior to ONS predicts a positive response to ONS. However, other studies concerned with proper patient selection claimed no predictive value for ONB. The aim of this study was to re-evaluate the usefulness and predictive value of ONB prior to ONS.

METHODS

Literature searches on the predictive value of ONB were performed in MEDLINE and PubMed. Patient data were extracted and a pooled analysis was performed.

RESULTS

The literature review revealed 133 patients with CM and seven patients with CCH who received preoperative ONB. To date, a randomized controlled study examining the relationship between ONB and ONS has not been conducted in patients with CM.

CONCLUSIONS

Current literature suggests that ONB does not sufficiently predict ONS responsiveness in patients with refractory CM and CCH; this important issue requires further investigation.

The phenomenological-existential comprehension of chronic pain: going beyond the standing healthcare models

A distinguishing characteristic of the biomedical model is its compartmentalized view of man. This way of seeing human beings has its origin in Greek thought; it was stated by Descartes and to this day it still considers humans as beings composed of distinct entities combined into a certain form. Because of this observation, one began to believe that the focus of a health treatment could be exclusively on the affected area of the body, without the need to pay attention to patient's subjectivity. By seeing pain as a merely sensory response, this model was not capable of encompassing chronic pain, since the latter is a complex process that can occur independently of tissue damage. As of the second half of the twentieth century, when it became impossible to deny the relationship between psyche and soma, the current understanding of chronic pain emerges: that of chronic pain as an individual experience, the result of a sum of physical, psychological, and social factors that, for this reason, cannot be approached separately from the individual who expresses pain. This understanding has allowed a significant improvement in perspective, emphasizing the characteristic of pain as an individual experience. However, the understanding of chronic pain as a sum of factors corresponds to the current way of seeing the process of falling ill, for its conception holds a Cartesian duality and the positivist premise of a single reality. For phenomenology, on the other hand, the individual in his/her unity is more than a simple sum of parts. Phenomenology sees a human being as an intending entity, in which body, mind, and the world are intertwined and constitute each other mutually, thus establishing the human being's integral functioning. Therefore, a real understanding of the chronic pain process would only be possible from a phenomenological point of view at the experience lived by the individual who expresses and communicates pain.

Lumbar paravertebral blockade as intractable pain management method in palliative care

Optimal symptoms control in advanced cancer disease, with refractory to conventional pain treatment, needs an interventional procedure. This paper presents coadministration of local anesthetic (LA) via paravertebral blockade (PVB) as the alternative to an unsuccessful subcutaneous fentanyl pain control in a 71-year old cancer patient with pathological fracture of femoral neck, bone metastases, and contraindications to morphine. Bupivacaine in continuous infusion (0.25%, 5 mL · hour⁻¹) or in boluses (10 mL of 0.125%–0.5% solution), used for lumbar PVB, resulted in pain relief, decreased demand for opioids, and led to better social interactions. The factors contributing to an increased risk of systemic toxicity from LA in the patient were: renal impairment; heart failure; hypoalbuminemia; hypocalcemia; and a complex therapy with possible drug-drug interactions. These factors were taken into consideration during treatment. Bupivacaine’s side effects were absent. Coadministered drugs could mask LA’s toxicity. Elevated plasma α1-acid glycoprotein levels were a protective factor. To evaluate the benefit-risk ratio of the PVB treatment in boluses and in constant infusion, bupivacaine serum levels were determined and the drug plasma half-lives were calculated. Bupivacaine’s elimination was slower when administered in constant infusion than in boluses (t_½ = 7.80 hours versus 2.64 hours). Total drug serum concentrations remained within the safe ranges during the whole treatment course (22.9–927.4 ng mL⁻¹). In the case presented, lumbar PVB with bupivacaine in boluses (≤ 137.5 mg · 24 hours⁻¹) was an easy to perform, safe, effective method for pain control. Bupivacaine in continuous infusion (≤150 mg · 12 hours⁻¹) had an acceptable risk-benefits ratio, but was ineffective.

Peripheral nerve stimulation for trigeminal neuropathic pain

Facial pain is a complex disease with a number of possible etiologies. Trigeminal neuropathic pain (TNP) is defined as pain caused by a lesion or disease of the trigeminal branch of the peripheral nervous system resulting in chronic facial pain over the distribution of the injured nerve. First line treatment of TNP includes management with anticonvulsant medication (carbamazepine, phenytoin, gabapentin, etc.), baclofen, and analgesics. TNP, however, can be a condition difficult to adequately treat with medical management alone. Patients with TNP can suffer from significant morbidity as a result of inadequate treatment or the side effects of pharmacologic therapy. TNP refractory to medical management can be considered for treatment with a growing number of invasive procedures. Peripheral nerve stimulation (PNS) is a minimally invasive option that has been shown to effectively treat medically intractable TNP. We present a case series of common causes of TNP successfully treated with PNS with up to a 2 year follow-up. Only one patient required implantation of new electrode leads secondary to electrode migration. The patients in this case series continue to have significant symptomatic relief, demonstrating PNS as an effective treatment option for intractable TNP. Though there are no randomized trials, peripheral neuromodulation has been shown to be an effective means of treating TNP refractory to medical management in a growing number of case series. PNS is a safe procedure that can be performed even on patients that are not optimal surgical candidates and should be considered for patients suffering from TNP that have failed medical management.