The current state of training in pain medicine fellowships: An Association of Pain Program Directors (APPD) survey of program directors.

INTRODUCTION: The Accreditation Council for Graduate Medical Education (ACGME) approved the first pain medicine fellowship programs over three decades ago, designed around a pharmacological philosophy. Following that, there has been a rise in the transition of pain medicine education toward a multidisciplinary interventional model based on a tremendous surge of contemporaneous literature in these areas. This trend has created variability in clinical experience and education amongst accredited pain medicine programs with minimal literature evaluating the differences and commonalities in education and experience of different pain medicine fellowships through Program Director (PD) experiences. This study aims to gather insight from pain medicine fellowship program directors across the country to assess clinical and interventional training, providing valuable perspectives on the future of pain medicine education. METHODS: This study involved 56 PDs of ACGME-accredited pain fellowship programs in the United States. The recruitment process included three phases: advanced notification, invitation, and follow-up to maximize response rate. Participants completed a standard online questionnaire, covering various topics such as subcategory fields, online platforms for supplemental education, clinical experience, postgraduate practice success, and training adequacy. RESULTS: Surveys were completed by 39/56 (69%) standing members of the Association of Pain Program Directors (APPD). All PDs allowed fellows to participate in industry-related and professional society-related procedural workshops, with 59% encouraging these workshops. PDs emphasized the importance of integrity, professionalism, and diligence for long-term success. Fifty-four percent of PDs expressed the need for extension of fellowship training to avoid supplemental education by industry or pain/spine societies. CONCLUSION: This study highlights the challenge of providing adequate training in all Pain Medicine subtopics within a 12-month pain medicine fellowship. PDs suggest the need for additional training for fellows and discuss the importance of curriculum standardization.

Radiofrequency Ablation for Chronic Lumbar Zygapophyseal Joint Pain Using a V-Shaped Active Tip Needle: An Observational Retrospective Study.

Background: Lumbar zygapophyseal joint dysfunction represents one of the major sources of chronic low back pain. Radiofrequency ablation (RFA) using a V-shaped active tip needle may offer a larger lesion of the medial branch nerves, improving clinical outcome. The aim of our study is to evaluate the efficacy and the feasibility of RFA using V-shaped active tip needles. Methods: This is a single-center observational retrospective study. Clinical records were screened and analyzed if they met the following inclusion criteria: adult patients (>18 years), diagnosis of chronic lumbar zygapophyseal joint pain, failure of conservative treatments, ability to provide informed consent for data analysis and publication. Exclusion criteria: lumbar pain not related to zygapophyseal joints, previous spinal/lumbar surgery, incomplete data, absence or withdrawal of informed consent. The primary outcome of the study was a change in pain intensity at follow-up. The secondary outcomes were the evaluation of quality-of-life improvement, the occurrence of adverse events and the impact on post-procedural analgesic consumption. For these purposes, pre- and post-treatment numeric rating scale (NRS), neuropathic pain 4 questions (DN4), EuroQoL - EQ-5D-3L, EQ-VAS, EQ-index and North American Spine Society (NASS) index were retrieved and analysed. Results: Sixty-four patients were included. 7.8% of patients at 1-month (CI95% 0.026, 0.173), 37.5% at 3-month (CI95% 0.257, 0.505), 40.6% at 6-month (CI95% 0.285, 0.536) and 35.9% at 9-month (CI95% 0.243, 0.489) follow-up reported a reduction of more than 80% in NRS Statistical analysis indicated a significant change in NRS, DN4, EQ-index and EQ-5D-VAS (p-value <0.001) at the different time-points. Conclusion: RFA using a V-shaped active tip needle might be a feasible and effective treatment for chronic lumbar zygapophyseal joint pain.

Interventional Pain Procedures: A Narrative Review Focusing On Safety and Complications. PART 2 Interventional Procedures For Back Pain.

In patients where conservative approaches have failed to relieve from chronic pain, interventional procedures may be an option in well selected patients. In recent years there has been an increase in the use and development of invasive procedures. Concomitantly, there has also been an increase in the complications associated with these procedures. Taken this into consideration, it is important for healthcare providers to take a cautious and vigilant approach, with a focus on patient safety, in order to minimize the risk of adverse events and ensure the best possible outcome for the patient. This may include careful selection of patients for procedures, use of proper techniques and equipment, and close monitoring and follow-up after the procedure. The aim of this narrative review is to summarize the primary complications associated with commonly performed image-guided (fluoroscopy or ultrasound-guided) interventional procedures and provide strategies to reduce the risk of these complications. We conclude that although complications from interventional pain procedures can be mitigated to a certain degree, they cannot be eliminated altogether. In order to avoid adverse events, patient safety should be given considerable attention and physicians should be constantly aware of the possibility of developing complications.

Bipolar Pulsed Radiofrequency for Trigeminal Neuralgia: A Report of Two Cases.

BACKGROUND: Trigeminal neuralgia (TN) is the most common cause of facial pain, leading to significant disability and impacting a patient's quality of life. Percutaneous procedures like continuous radiofrequency, pulsed radiofrequency (PRF), and combined continuous and pulsed radiofrequency have been studied in past years comparing different voltages in order to find more effective therapies with fewer complications (eg, numbness and masseter muscle weakness). With regard to young patients, there is still insufficient evidence on the most appropriate procedure in this patient population. PRF does not cause thermal damage. The mechanism of action involves delivering an electrical field to targeted nerves or tissues, modulating pain. We propose that bipolar pulsed radiofrequency (2 parallel cannulas) in the trigeminal ganglion produce a denser and larger field resulting in more effective controlled pain. CASE PRESENTATION: We present 2 cases of 40- and 48-year-old men with severe V2 to V3 TN who underwent bipolar PRF. We performed bipolar PRF on the trigeminal ganglion through the foramen ovale using two 22-gauge 100-mm cannulas with 10-mm active tips. Parameters used were voltage of 85 V, pulse width of 20 milliseconds, and total duration time of 6 minutes. Both patients reported complete relief of pain after the procedure, and at 2-year follow-up they were pain free and experienced a better quality of life. No complications were reported. CONCLUSION: Bipolar PRF could be a non-neurodestructive option for young people with TN and deserves further investigation as a treatment option.

The anatomy of the peridural membrane of the human spine.

A peridural membranous layer exists between the bony wall of the spinal canal and the dura mater, but reports on the anatomy of this structure have been inconsistent. The objective of this study is to give a precise description of the peridural membrane (PDM) and to define it unambiguously as a distinct and unique anatomical entity. Thirty-four cadaveric sections of human thoraco-lumbar spines were dissected. On gross examination, the PDM appears as a smooth hollow tube that covers the bony wall of the spinal canal. An evagination of this tube into the neural foramen contains the exiting spinal nerve. The entire epidural venous plexus, including its extension into the neural foramina, is contained in the body of the PDM. Histological examination of the PDM shows a variable distribution of veins arteries, lymphatics, and nerves embedded in a continuous sheath of fibrous, areolar, and adipose tissue. The posterior longitudinal ligament may be considered a dense condensation of fibrous tissue within the membrane. Thus, the PDM is a unique, continuous, and complete anatomical structure. In the spinal canal, the PDM is adjacent to the periosteum. In the neural foramen, suprapedicular PDM and pedicular periosteum separate anatomically to form a suprapedicular compartment, bounded anteriorly by the intervertebral disc and posteriorly by the facet joint. Trauma or degeneration of the disc or facet joint may lead to inflammation and pain sensitization of PDM. This protective mechanism may be of considerable importance for the functioning of the spine under conditions of strain.

The peridural membrane of the spine has characteristics of synovium.

The peridural membrane (PDM) is a well-defined structure between dura mater and the wall of the spinal canal. The spine may be viewed as a multi-segmented joint, with the epidural cavity and neural foramina as joint spaces and PDM as synovial lining. The objective of this investigation was to determine if PDM has histological characteristics of synovium. Samples of the PDM of the thoraco-lumbar spine were taken from 23 human cadavers and analyzed with conventional light microscopy and confocal microscopy. Results were compared to reports on similar analyses of synovium in the literature. Histological distribution of areolar, fibrous, and adipose connective tissue in PDM was similar to synovium. The PDM has an intima and sub-intima. No basement membrane was identified. CD68, a marker for macrophage-like-synoviocytes, and CD55, a marker for fibroblast-like synoviocytes, were seen in the lining and sub-lining of the PDM. Multifunctional hyaluronan receptor CD44 and hyaluronic acid synthetase 2 marker HAS2 were abundantly present throughout the membrane. Marked presence of CD44, CD55, and HAS2 in the well-developed tunica muscularis of blood vessels and in the body of the PDM suggests a role in the maintenance and lubrication of the epidural cavity and neural foramina. Presence of CD68, CD55, and CD44 suggests a scavenging function and a role in the inflammatory response to noxious stimuli. Thus, the human PDM has histological and immunohistochemical characteristics of synovium. This suggests that the PDM may be important for the homeostasis of the flexible spine and the neural structures it contains.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 1: A Minimally Invasive Assessment in Unembalmed Cadavers.

STUDY DESIGN: A cross-sectional cadaveric examination of displacement and strain measured at the level of the cervical nerve roots during upper limb neural tension testing (ULNTT) with median nerve bias. OBJECTIVE: To determine the displacement and strain of cervical nerve roots C5-C8 during ULNTT with minimal disruption of surrounding tissues. SUMMARY OF BACKGROUND DATA: Clinical examination of neural pathology involving cervical nerve roots is difficult because of the transient nature of pathologies, such as cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. Cadaveric studies have demonstrated significant displacement and strain in lumbosacral nerve roots during neurodynamic testing of the lower extremity. Examination into the biomechanical behaviors of cervical nerve roots during ULNTT has not been performed. METHODS: Eleven unembalmed cadavers were positioned supine as though undergoing ULNTT. Radiolucent markers were implanted into cervical nerve roots C5-C8. Posteroanterior fluoroscopic images were captured at resting and ULNTT positioning. Images were digitized and displacement and strain were calculated. RESULTS: ULNTT resulted in significant inferolateral displacement (average, 2.16 mm-4.32 mm, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in inferolateral displacement between the C5 and C6 nerve roots (3.15 mm vs. 4.32 mm, P = 0.009). ULNTT resulted in significant strain (average, 6.80%-11.87%, P < 0.001) of cervical nerve roots C5-C8. There was a significant difference in strain between the C5 and C6 nerve roots (6.60% vs. 11.87%, P = 0.03). CONCLUSION: ULNTT caused significant inferolateral displacement and strain in cervical nerve roots C5-C8. These results provide the mechanical foundation for the use of ULNTT in clinical evaluation of pathology in the cervical region, such as in cervical radiculopathy, entrapment neuropathies, and thoracic outlet syndrome. LEVEL OF EVIDENCE: 2.

2015 Young Investigator Award Winner: Cervical Nerve Root Displacement and Strain During Upper Limb Neural Tension Testing: Part 2: Role of Foraminal Ligaments in the Cervical Spine.

STUDY DESIGN: A cross-sectional cadaveric examination of the mechanical effect of foraminal ligaments on cervical nerve root displacement and strain. OBJECTIVE: To determine the role of foraminal ligaments by examining differences in cervical nerve root displacement and strain during upper limb neural tension testing (ULNTT) before and after selective cutting of foraminal ligaments. SUMMARY OF BACKGROUND DATA: Although investigators have determined that lumbar spine foraminal ligaments limit displacement and strain of lumbosacral nerve roots, similar studies have not been conducted to prove that it is true for the cervical region. Because the size, shape, and orientation of cervical spine foraminal ligaments are similar to those in the lumbar spine, it is hypothesized that foraminal ligaments in the cervical spine will function in a similar fashion. METHODS: Radiolucent markers were implanted into cervical nerve roots C5-C8 of 9 unembalmed cadavers. Posteroanterior fluoroscopic images were captured at resting and upper limb neural tension testing positioning before and after selective cutting of foraminal ligaments. RESULTS: Selective cutting of foraminal ligaments resulted in significant increases in inferolateral displacement (average, 2.94 mm [ligaments intact]-3.87 mm [ligaments cut], P < 0.05) and strain (average, 9.33% [ligaments intact]-16.31% [ligaments cut], P < 0.03) of cervical nerve roots C5-C8 during upper limb neural tension testing. CONCLUSION: Foraminal ligaments in the cervical spine limited cervical nerve root displacement and strain during upper limb neural tension testing. Foraminal ligaments seem to have a protective role, reducing displacement and strain to cervical nerve roots during tension events. LEVEL OF EVIDENCE: 2.

Prevalence of adverse reactions to radiopaque contrast reported by patients presenting for interventional pain procedure.

INTRODUCTION: Adverse reactions to radiopaque contrast media (RCM) are well documented with a wide range of incidences reported. The objective of this study was to determine how many patients in a sample of 200 who presents for interventional pain treatments report a history of adverse reactions to RCM. METHODS: Data from 200 outpatients were collected using a self-administered questionnaire. The questionnaire was designed to obtain information about prior exposure to RCM and any adverse events plus other general information about allergic reactions including known risk factors for allergic reactions. Demographic data and information about past medical history were obtained from each patient. RESULTS: Of the 200 patients surveyed, 16 reported having had an allergic reaction to RCM. The events met criteria for immediate hypersensitivity reaction. Chemotoxic reactions cannot be ruled out. Of factors associated with risk of allergic reaction, none were clearly more prevalent in subjects reporting an allergic reaction vs. subjects who did not. Atopic patients generally considered susceptible to contrast allergy reported no hypersensitivity reaction. The number of medications and foods the subjects reported caused them to have allergic reactions was extensive. CONCLUSION: Patients with a history suggestive of an immediate hypersensitivity reaction to RCM may report for interventional pain procedures normally performed with RCM. Patients who have experienced an immediate hypersensitivity reaction to RCM have increased risk for another reaction if injected again with contrast agent. Therefore, facilities should be prepared to implement measures to prevent recurrent reactions.

Hyaluronidase: a review of approved formulations, indications and off-label use in chronic pain management.

IMPORTANCE OF THE FIELD: Hyaluronidase for injection is an adjuvant that increases the absorption and dispersion of other injected drugs or fluids (hypodermoclysis); and improves absorption of radiopaque agents in subcutaneous urography. Ovine hyaluronidase is approved for the treatment of vitreous hemorrhages. AREAS COVERED IN THIS REVIEW: We review approved indications for injectable hyaluronidase and off-label uses as well as safety, efficacy and dosing information. We compare formulations made using animal tissue extracts versus the novel human recombinant type. Emphasis is on the human recombinant form and off-label uses in patients with chronic pain. WHAT THE READER WILL GAIN: Hyaluronidase reduces the obstacle that the interstitial matrix presents to fluid and drug transfer. It is a mucolytic enzyme derived from mammalian tissue or synthesized in vitro in pure form (rHuPH20) using recombinant technology. Hyaluronidase is used off-label in chronic pain management to facilitate removal of epidural adhesions with mechanical and/or hydrostatic forces and to treat edema. TAKE HOME MESSAGE: The recently introduced rHuPH20 formulation obviates any risk of allergic reaction or prion-related illnesses. Reduction of edema by hyaluronidase and facilitation of epidural adhesioloysis may be beneficial in treating certain chronic painful conditions.

Neurogenic bladder: a complication after endoscopic adhesiolysis with return of bladder function while using nitrofurantoin.

We describe the case of a 73-year-old woman with a history of chronic low back pain and 2 previous lumbar fusions who presented with complaints of worsening back and leg pain. Having previously undergone multiple interventions, physical therapy, and oral analgesics with limited pain relief, the patient opted for endoscopic lysis of adhesions for severe scarring of the epidural space. Subsequently, the patient developed a neurogenic bladder with urinary retention. Three years later, she experienced resolution of the neurogenic bladder symptoms that coincided with the use of the antibiotic nitrofurantoin. Upon discontinuation of the antibiotic, the patient noted that she was unable to void spontaneously. With reinstitution of nitrofurantoin, the patient was once again able to void effectively and has been maintained on nitrofurantoin for >3 years.

Evidence-based interventional pain medicine according to clinical diagnoses. 3. Persistent idiopathic facial pain.

Persistent idiopathic facial pain, previously known as atypical facial pain, is described as a persistent facial pain that does not have the classical characteristics of cranial neuralgias and for which there is no obvious cause (International Classification of Headache Disorders in 2004). According to these criteria, the diagnosis is possible if the facial pain is localized, present daily, and throughout all or most of the day. By definition, neurological and physical examination findings in persistent idiopathic facial pain should be normal. Forming a diagnosis is not simple and follows a process of elimination of other causes of facial pain. The precise incidence is unknown. The affliction is seen primarily in older adults and rarely in children. The pathophysiology is unknown. In persistent idiopathic facial pain, there is no abnormal processing of somatosensory stimuli in the pain area or facial area of the primary somatosensory cortex of the brain. The treatment is difficult and often requires a multidisciplinary approach. The most important part of the treatment is psychological counseling and pharmacological therapy. Pharmacological treatment with tricyclic antidepressants and anti-epileptic drugs can be tried. The conservative, pharmacological treatment with amitryptiline is the primary choice. Venlafaxine and fluoxetine treatment can also be considered. When the pharmacological treatment fails, pulsed radiofrequency treatment of the ganglion pterygopalatinum (sphenopalatinum) can be considered (2 C+).

Recent advancements in the treatment of lumbar radicular pain.

PURPOSE OF REVIEW: Lumbar radicular pain is a common and often difficult condition to treat. Current literature supports the theory that radicular pain is at least in part due to an inflammatory process involving cytokines, including tumor necrosis factor alpha and interleukins. This review summarizes some of the most recent research concerning the use of tumor necrosis factor alpha antagonists and interleukin receptor antagonists in the treatment of lumbar radicular pain. RECENT FINDINGS: Recent studies have shown promising results in the treatment of both acute and chronic lumbar radicular pain with tumor necrosis factor alpha antagonists such as etanercept and infliximab, as well as with interleukin receptor antagonists. SUMMARY: Treatment for lumbar radicular pain has long included epidural steroids to inhibit the inflammatory component of radicular pain. Recent studies have more precisely identified the cytokines responsible for this inflammatory process and indicate that inhibition of these cytokines may offer more specific and effective treatment for lumbar radicular pain.

Ziconotide: an update and review.

BACKGROUND: Ziconotide is the only N-type calcium channel blocker approved by the US FDA for the treatment of chronic pain. The approved indication is for the management of severe chronic pain in patients for whom intrathecal therapy is warranted and who are intolerant of or refractory to other treatments such as systemic analgesics, adjunctive therapies or intrathecal morphine. OBJECTIVE: The purpose of this article was to review the available safety, efficacy and dosing information for ziconotide. METHODS: The sources searched for literature from 1980 to January 2008 included Pub Med, MEDLINE and PREMEDLINE using the words ziconotide, conotoxins and pain. RESULTS/CONCLUSION: Ziconotide is administered intrathecally by infusion pump to block nociceptive signal transmission in the spinal cord. It is a synthetic neuroactive peptide equivalent to the omega conotoxin MVIIA, a constituent of the venom of the fish-hunting marine snail Conus magus. It is highly potent, has a steep dose-response curve, a slow onset of action and a narrow margin of safety and responses to dose adjustments are slow. Patients receiving ziconotide should be under the care of physicians experienced in the management of intrathecal infusion therapy for pain control and should have convenient access to medical facilities.

Sympathetic blocks: the evidence.

The sympathetic nervous system has been implicated in numerous pain syndromes ranging from neuropathic pain to vascular pain to visceral pain. In light of this, sympathetic ganglia have been the target of local anesthetic blockade to determine the sympathetic role in the transmission of pain. If analgesia is afforded with local anesthetic blockade, chemical or thermal neurolysis have been utilized to attempt to provide long-term relief. Despite frequent use of minimally invasive sympathetic blocks and neurolysis by pain practitioners, their efficacy for providing analgesia has been sparsely reported in the literature. Many case reports and case series have been published, but few placebo-controlled, blinded studies exist. This manuscript will review the literature on sympathetic blocks and summarize existing studies for each of the sympathetic blocks. The goal is to provide past, current, and future pain physicians with evidence that they can use to provide appropriate care for their patients.

Infraclavicular brachial plexus block and infusion for treatment of long-standing complex regional syndrome type 1: a case report.

Complex regional pain syndrome type 1 (CRPS 1) is a perplexing chronic pain condition that frustrates physicians and patients alike. The etiology of the condition resides in multiple theories and diagnosis can be difficult. Therapy focuses on pain management and restoration of physical function. Conservative treatment includes both non-pharmacological and pharmacological methods. Invasive therapy centers on sympathetic and somatic blocks and may evolve to neuromodulatory or neuraxial techniques. In patients with severe pain and extremity contractures with CRPS, often times the invasive blocks help in reduction of resting pain, but are ineffective in alleviating pain related to aggressive physical therapy. Continuous regional blockade with a percutaneous catheter is an effective, but seldom reported technique that can be used to treat both resting and movement related pain. This presentation reviews the results of an infraclavicular brachial plexus infusion used to treat CRPS 1 that developed in a 49 year-old woman following a work-related upper extremity injury. The patient made a dramatic recovery with the infusion, which was maintained for two weeks. A T2-T3 sympathetic radiofrequency thermocoagulation was then performed to maintain pain relief and the infusion was stopped. The patient returned to work and has done well over the ensuing 19 months.