Anatomical Study of the Innervation of Triangular Fibrocartilage Complex and Distal Radioulnar and Radiocarpal Joints: Implications for Denervation.

PURPOSE: Open and percutaneous denervation is an emerging technique for joint pain. This study investigated the course and distribution of the articular branches innervating the triangular fibrocartilage complex (TFCC), distal radioulnar joint (DRUJ), and radiocarpal joint (RCJ) relative to bony and soft tissue landmarks to guide wrist denervation procedures. METHODS: Fourteen formalin-embalmed specimens were serially dissected to expose the origin, course, and distribution of articular branches innervating the TFCC, DRUJ, and RCJ. Bony and soft tissue landmarks to localize each articular branch were documented and visualized on a 3-dimensional reconstruction of the bones of the distal forearm and hand. RESULTS: The TFCC was innervated by articular branches from the posterior interosseus nerve (10 of 14 specimens), dorsal cutaneous branch of the ulnar nerve (14 of 14 specimens), palmar cutaneous branch of the ulnar nerve (12 of 14 specimens), and medial antebrachial cutaneous nerve (9 of 14 specimens). The DRUJ was innervated by the posterior interosseus nerve (9 of 14 specimens) and anterior interosseus nerve (14 of 14 specimens). The RCJ was innervated by the posterior interosseus nerve (14 of 14 specimens), superficial branch of the radial nerve (5 of 14 specimens), lateral antebrachial cutaneous nerve (14 of 14 specimens), and palmar cutaneous branch of the median nerve (10 of 14 specimens). CONCLUSIONS: Multiple nerves were found to innervate the TFCC, DRUJ, and RCJ. The relationship of anatomical landmarks to specific articular branches supplying the TFCC, DRUJ, and RCJ can inform selective denervation procedures based on the structural origin of pain. CLINICAL RELEVANCE: The detailed documentation of the spatial relationship of the nerve supply to the wrist provides clinicians with the anatomical basis to optimize current, and develop new denervation protocols to manage chronic wrist pain.

Chemical Ablation of Genicular Nerve with Phenol for Pain Relief in Patients with Knee Osteoarthritis: A Prospective Study.

BACKGROUND: Radiofrequency ablation of the genicular nerve is performed for knee osteoarthritis (KOA) when conservative treatment is not effective. Chemical ablation may be an alternative, but its effectiveness and safety have not been examined. The objective of this prospective open-label cohort study is to evaluate the effectiveness and safety of ultrasound-guided chemical neurolysis for genicular nerves with phenol to treat patients with chronic pain from KOA. METHODS: Forty-three patients with KOA with pain intensity score (Numeric Rating Scale, NRS) ≥ 4, and duration of pain of more than 6 months were considered for enrollment. Ultrasound-guided diagnostic blocks of genicular nerves (superomedial, inferomedial, and superolateral) with 1.5 mL of 0.25% bupivacaine at each site were performed. Those who reported more than 50% reduction in NRS went on to undergo chemical neurolysis, using 1.5 mL 7% glycerated phenol in each genicular nerve. NRS and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were assessed before intervention and at 2 weeks and 1, 2, 3, and 6 months following the intervention. RESULTS: NRS and WOMAC scores improved at all time points. Mean pain intensity improved from 7.2 (95% confidence interval [CI]: 6.8 to 7.7) at baseline to 4.2 (95%CI: 3.5 to 5.0) at 6-month follow-up (P < 0.001). Composite WOMAC score improved from 48.7 (95%CI: 43.3 to 54.2) at baseline to 20.7 (95%CI: 16.6 to 24.7) at 6-month follow-up (P < 0.001). Adverse events did not persist beyond 1 month and included local pain, hypoesthesia, swelling, and bruise. CONCLUSION: Chemical neurolysis of genicular nerves with phenol provided efficacious analgesia and functional improvement for at least 6 months in most patients with a low incidence of adverse effects.

Chemical Hip Denervation for Inoperable Hip Fracture.

BACKGROUND: Hip fracture is a challenging geriatric problem for the health care professionals, especially in patients with multiple comorbidities. In patients with inoperable hip fracture secondary to severe comorbid conditions, the pain can lead to significant challenges in nursing care. With the current understanding of the innervation of hip joint, we are now able to perform selective chemical denervation of the articular branches of femoral and obturator nerves to manage the pain associated with inoperable hip fracture. METHODS: In this retrospective case series, we analyzed 20 consecutive patients with inoperable hip fracture who received chemical denervation and examined the effect of the denervation on pain and functional outcomes, including the maximally tolerable hip flexion and the ability to sit during their hospital stay. We also assessed the likelihood of being ambulatory as a long-term outcome. RESULTS: The movement-related pain was significantly reduced at 10 minutes postprocedure, on postintervention days 1 and 5 (P values of <.001), and the degree of maximally tolerable hip flexion was doubled at the same time points (P values of <.001, .003, and .002, respectively). Fifty percent of the patients managed to sit within the first 5 days after procedure, and 3 of them managed to walk with aid 4 months after hip denervation. No procedural adverse event was noted. CONCLUSIONS: We concluded that this chemical hip denervation could be a safe and effective measure to handle the pain-related and rehabilitation-related challenges as a result of inoperable hip fracture.

Can recent chronic pain techniques help with acute perioperative pain?

PURPOSE OF REVIEW: This article discussed how the knowledge and technique of a few chronic pain procedures benefited the perioperative clinicians in their care of patients receiving specific orthopaedic surgical procedures. RECENT FINDINGS: Recent emerging interest in hip and knee denervation for chronic pain management secondary to osteoarthritis stimulates publications on the new understanding of hip and knee joint innervation. The improved understanding of the anatomy allows better precision in targeting the articular branches. The procedures for chronic joint pain such as radiofrequency ablation, chemical neurolysis and neuromodulation procedure have recently been applied to the perioperative care in orthopaedic procedures because of the potential long-lasting analgesia, opioid-sparing effect and consequent improvement in physical function and health-related quality of life after surgery. SUMMARY: Despite the widespread use of regional anaesthesia and multimodal analgesia in the perioperative pain management, more than two-third of the patients reported severe postoperative pain. Therefore, other therapeutic strategies used in chronic pain management such as radiofrequency ablation and neuromodulation have been proposed to optimize acute postsurgical pain. The early experience with those techniques is encouraging, and more studies are required to explore the incorporation of these procedures in the perioperative care.

Comparison of Fluoroscopy and Ultrasound Guidance for Sacroiliac Joint Injection in Patients with Chronic Low Back Pain.

BACKGROUND AND OBJECTIVES: Sacroiliac joint (SIJ) arthritis is a common cause of chronic mechanical low back pain (LBP) that is often treated with injection of local anesthetic and steroids. Ultrasound (US) has emerged as a viable alternative to fluoroscopy (FL) to guide SIJ injections; however, few studies have compared these modalities. In this prospective randomized, controlled trial, we compared both accuracy and efficacy of US and FL guidance for SIJ injections. METHODS: Forty patients with chronic moderate-to-severe LBP secondary to SIJ arthritis were randomized to receive US- or FL-guided unilateral SIJ injections. Primary outcomes included pain at 1 month measured by numerical rating scale (NRS) scores. Secondary outcomes included NRS scores at 24 hours, 72 hours, 1 week, and 3 months after injection, physical functioning at 1 month after the procedure, procedure time, incidence of intra-articular and peri-articular needle placement, patient discomfort, overall patient satisfaction, and daily opioid consumption. RESULTS: There was no significant difference in NRS pain scores between the 2 groups at 1 month or at any other follow-up points. A significant reduction from baseline mean NRS scores was observed in both groups at 1 month after injection (US 22.7%, P = 0.025; FL 37.3%, P < 0.001). There was no significant difference in procedure-related variables, physical functioning, discomfort, opioid utilization, and patient satisfaction between the 2 groups. CONCLUSIONS: Ultrasound-guided SIJ injection with fluoroscopic confirmation has similar accuracy and efficacy to fluoroscopy alone for SIJ injections in patients with chronic low back pain secondary to SIJ arthritis.

Ultrasound-Guided Interventions for Carpal Tunnel Syndrome: A Systematic Review and Meta-Analyses.

Carpal tunnel syndrome (CTS) is the most common peripheral entrapment, and recently, ultrasound-guided perineural injection (UPIT) and percutaneous flexor retinaculum release (UPCTR) have been utilized to treat CTS. However, no systematic review or meta-analysis has included both intervention types of ultrasound-guided interventions for CTS. Therefore, we performed this review using four databases (i.e., PubMed, EMBASE, Scopus, and Cochrane) to evaluate the quality of evidence, effectiveness, and safety of the published studies on ultrasound-guided interventions in CTS. Among sixty studies selected for systemic review, 20 randomized treatment comparison or controlled studies were included in six meta-analyses. Steroid UPIT with ultrasound guidance outperformed that with landmark guidance. UPIT with higher-dose steroids outperformed that with lower-dose steroids. UPIT with 5% dextrose in water (D5W) outperformed control injection and hydrodissection with high-volume D5W was superior to that with low-volume D5W. UPIT with platelet-rich plasma outperformed various control treatments. UPCTR outperformed open surgery in terms of symptom improvement but not functional improvement. No serious adverse events were reported in the studies reviewed. The findings suggest that both UPIT and UPCTR may provide clinically important benefits and appear safe. Further treatment comparison studies are required to determine comparative therapeutic efficacy.

Evaluation of sonoanatomy relevant to performing stellate ganglion blocks using anterior and lateral simulated approaches: an observational study.

PURPOSE: Stellate (cervicothoracic) ganglion block (SGB) can be associated with serious complications, such as esophageal and vascular injury. The objective of this study was to evaluate the potential for vascular and esophageal injury in healthy subjects by examining the sonoanatomy of the neck relevant to the SGB at the sixth (C6) and seventh (C7) cervical vertebral levels and determining the incidence of blood vessels and esophagi in the simulated path of needle insertion in the conventional and two different ultrasound-guided approaches used to perform a SGB. METHODS: Ultrasound scanning of the neck at the C6 and C7 cervical vertebral levels was performed in 100 adult subjects, and the following measurements were obtained: the degree of deviation of the esophagus relative to the larynx/trachea; the likelihood of encountering a vessel in the simulated path of needle insertion in the two different approaches to SGB; the incidence of the vertebral artery being situated outside the foramen transversarium at the C6 level; and the distance of the simulated path of needle insertion in the anterior and lateral approaches to SGB at the C6 level. RESULTS: The position of the esophagus was found to be variable but lateral to the airway in 50% and 74% of the subjects at C6 and C7, respectively. The esophagus covered more than half of the distance between the airway and the carotid artery in 14% and 44% of the subjects at the C6 and C7 levels, respectively. With the anterior approach, a major vessel was observed in up to 29% and 43% of patients at the C6 and C7 levels, respectively. The vertebral artery was outside the foramen transversarium in 7% of subjects at the C6 level. CONCLUSION: Major blood vessels and the esophagus are in close proximity to needle pathways during the anterior approach to SGB performed with either anatomic landmarking or fluoroscopic guidance. An ultrasound-guided lateral approach at the C6 level may possibly confer a greater margin of safety for performing SGB.

Intake assessment of problematic use of medications in a chronic noncancer pain clinic.

BACKGROUND: The present article outlines the process of instituting an assessment of risk of problematic use of medications with new patients in an ambulatory chronic noncancer pain (CNCP) clinic. It is hoped that the authors' experience through this iterative process will fill the gap in the literature by setting an example of an application of the 'universal precautions' approach to chronic pain management. OBJECTIVES: To assess the feasibility and utility of the addition of a new risk assessment process and to provide a snapshot of the risk of problematic use of medications in new patients presenting to a tertiary ambulatory clinic treating CNCP. METHODS: Charts for the first three months following the institution of an intake assessment for risk of problematic medication use were reviewed. Health care providers at the Wasser Pain Management Centre (Toronto, Ontario) were interviewed to discuss the preliminary findings and provide feedback about barriers to completing the intake assessments, as well as to identify the items that were clinically relevant and useful to their practice. RESULTS: Data were analyzed and examined for completeness. While some measures were considered to be particularly helpful, other items were regarded as repetitive, problematic or time consuming. Feedback was then incorporated into revisions of the risk assessment tool. DISCUSSION: Overall, it is feasible and useful to assess risk for problematic use of medications in new patients presenting to CNCP clinics. CONCLUSION: To facilitate the practice of assessment, the risk assessment tool at intake must be concise, clinically relevant and feasible given practitioner time constraints.

Hip Ablation Techniques.

Radiofrequency ablation (RFA) is still an emergent technique for the management of chronic hip pain. Although the ablation technique for facet articular branches of lumbar and cervical spine was already established, the literature on the targets and technique of needle placement for hip denervation are evolving. This article summarizes the current understanding of the anatomy of the articular branches, sonoanatomy, and the suggested techniques for the RFA of the hip. It also reviews the literature on the clinical studies.

Knee Ablation Approaches.

Genicular nerve radiofrequency ablation has quickly become one of the most promising interventions for chronic knee pain secondary to osteoarthritis, with consistent improvements in pain and function. Although there are multiple techniques using slightly variable lesion locations, cannulas, lesion types, and imaging modalities, the clinical effectiveness targeting the anterior branches of the superior medial, superolateral, and inferior medial has reproducibly demonstrated clinically and statistically significant improvements up to 24 months after the procedure with minimal adverse events. This article summarizes the current knowledge of the sensory innervation of the knee joint, the principles of radiofrequency ablation, and the current literature on clinical outcomes.

Overview of Innervation of Knee Joint.

Image-guided diagnostic block and radiofrequency ablation of the knee joint to manage pain require detailed understanding of joint innervation in relation to soft tissue and bony landmarks. In this article, the origin, course, and relationship to anatomic landmarks of articular nerves supplying the knee joint are discussed. The innervation pattern of the anterior and posterior aspects of the knee joint capsule is relatively consistent, with some variation in supply by the saphenous, anterior division of obturator, and common fibular nerves. To improve nerve capture rates for diagnostic block and radiofrequency ablation, multiple target sites could be beneficial.

Cognitive behavioral therapy for insomnia in patients with chronic pain - A systematic review and meta-analysis of randomized controlled trials.

Several randomized controlled trials have implemented cognitive behavioral therapy for insomnia (CBT-I) for patients with comorbid insomnia and chronic pain. This systematic review and meta-analysis investigated the effectiveness of CBT-I on patient-reported sleep, pain, and other health outcomes (depressive symptoms, anxiety symptoms, and fatigue) in patients with comorbid insomnia and chronic non-cancer pain. A systematic literature search was conducted using eight electronic databases. Upon duplicate removal, 6374 records were screened against the inclusion criteria. Fourteen randomized controlled trials were selected for the review, with twelve (N = 762 participants) included in the meta-analysis. At post-treatment, significant treatment effects were found on global measures of sleep (standardized mean difference = 0.89), pain (0.20), and depressive symptoms (0.44). At follow-up (up to 12 mo), CBT-I significantly improved sleep (0.56). Using global measures of sleep, we found a probability of 81% and 71% for having better sleep after CBT-I at post-treatment and final follow-up, respectively. The probability of having less pain after CBT-I at post-treatment and final follow-up was 58% and 57%, respectively. There were no statistically significant effects on anxiety symptoms and fatigue at either assessment point. Future trials with sufficient power, longer follow-up periods, and inclusion of CBT for pain components are warranted.

Ultrasound-guided suprascapular nerve block: a correlation with fluoroscopic and cadaveric findings.

PURPOSE: Previous work on the ultrasound-guided injection technique and the sonoanatomy of the suprascapular region relevant to the suprascapular nerve (SSN) block suggested that the ultrasound scan showed the presence of the suprascapular notch and transverse ligament. The intended target of the ultrasound-guided injection was the notch. The objective of this case report and the subsequent cadaver dissection findings is to reassess the interpretation of the ultrasound images when locating structures for SSN block. CLINICAL FEATURES: A 45-yr-old man with chronic shoulder pain received an ultrasound-guided SSN block using the suprascapular notch as the intended target. The position of the needle was verified by fluoroscopy, which showed the tip of the needle well outside the suprascapular notch. Similar ultrasound-guided SSN blocks were performed in two cadavers. Dissections were performed which showed that the needle tips were not at the suprascapular notch but, more accurately, were close to the SSN but at the floor of the suprascapular fossa between the suprascapular and spinoglenoid notch. CONCLUSION: Our fluoroscopic and cadaver dissection findings both suggest that the ultrasound image of the SSN block shown by the well-described technique is actually targeting the nerve on the floor of the suprascapular spine between the suprascapular and spinoglenoid notches rather than the suprascapular notch itself. The structure previously identified as the transverse ligament is actually the fascia layer of the supraspinatus muscle.

Ultrasound-Guided Hydrodissection for Baxter's Neuropathy Secondary to Plantar Fasciitis: A Case Report.

Plantar heel pain is a common pain condition encountered in clinical practice. The common etiologies include plantar fasciitis, calcaneal spur, calcaneus stress fracture, systemic causes, and trauma. Neurogenic causes, including entrapment at the tarsal tunnel or Baxter's nerve entrapment, can contribute to the heel pain and should not be overlooked. In this case report, we describe a patient with severe heel pain, presenting with overlapping features of plantar fasciitis and neuropathic pain. Magnetic resonance imaging suggested Baxter's nerve entrapment, and a subsequent ultrasound-guided hydrodissection of Baxter's nerve provided long-lasting pain relief.

Sleep-disordered breathing in patients on opioids for chronic pain.

The past two decades has seen a substantial rise in the use of opioids for chronic pain, along with opioid-related mortality and adverse effects. A contributor to opioid-associated mortality is the high prevalence of moderate/severe sleep-disordered breathing, including central sleep apnea and obstructive sleep apnea, in patients with chronic pain. Although evidence-based treatments are available for sleep-disordered breathing, patients are not frequently assessed for sleep-disordered breathing in pain clinics. To aid healthcare providers in this area of clinical uncertainty, we present evidence on the interaction between opioids and sleep-disordered breathing, and the prevalence and predictive factors for sleep-disordered breathing in patients on opioids for chronic pain. We provide recommendations on how to evaluate patients on opioids for risk of moderate/severe sleep-disordered breathing in clinical care, which could lead to earlier use of therapeutic interventions for opioid-associated sleep-disordered breathing, such as opioid cessation or positive airway pressure therapy. This would improve quality of life and well-being of patients with chronic pain.

Evaluation of Sensory Mapping of Erector Spinae Plane Block.

BACKGROUND: Erector spinae plane (ESP) block is an effective regional analgesic technique for thoracic and abdominal pain. The volume of local anesthetic (LA) needed to produce sensory block in the spinal segment is unknown. OBJECTIVES: The aim of the present study was to examine the extent of dermatomal spread following ultrasound-guided administration of ESP block, with a fixed-volume dose of a LA at the midthoracic area for analgesia in acute thoracic pain patients. Secondary objectives were postprocedure analgesia and patient satisfaction. STUDY DESIGN: This research used a prospective unicentric exploratory cohort design. SETTING: The study was conducted at an academic university hospital. METHODS: A total of 18 patients with acute severe chest pain including rib fractures, thoracic postoperative rescue analgesia, zoster herpetic neuritis, and myofascial pain syndrome received ESP block under ultrasound guidance at the T5-T7 levels. Twenty mL of 0.5% plain bupivacaine was injected. Evaluation of the sensory block was carried out 60 minutes following the completion of the ESP block via a change in sensation to pinprick and cold methods. The Visual Analog Scale (VAS) for pain was recorded one hour after the procedure. Patient satisfaction was reported using a 4-point Likert scale. This study was registered with the clinicaltrials.gov database (identifier: NCT03831581). RESULTS: Sixteen patients had a successful ESP block; 2 patients were excluded for a failed block. The mean dermatomal spread was 9 (range, 8-11). VAS scores improved by at least 50% from baseline (P < .05), one hour after the ESP block. The degree of satisfaction reported by all patients on the Likert scale was 4 points. No major complications were observed. LIMITATIONS: This study was limited by its sample size. CONCLUSIONS: An ultrasound-guided ESP block with a single injection at the midthoracic level with 20 mL of 0.5% plain bupivacaine provides a mean dermatomal spread of 9 dermatomes (range, 8-11) with a high rate of analgesic efficacy and low incidence of adverse effects. KEY WORDS: Acute pain, dermatomal spread, erector spine plane nerve block, thoracic pain, thoracic postoperative analgesia.

Predictors of postoperative pain and analgesic consumption: a qualitative systematic review.

Pain is a subjective and multidimensional experience that is often inadequately managed in clinical practice. Effective control of postoperative pain is important after anesthesia and surgery. A systematic review was conducted to identify the independent predictive factors for postoperative pain and analgesic consumption. The authors identified 48 eligible studies with 23,037 patients included in the final analysis. Preoperative pain, anxiety, age, and type of surgery were four significant predictors for postoperative pain. Type of surgery, age, and psychological distress were the significant predictors for analgesic consumption. Gender was not found to be a consistent predictor as traditionally believed. Early identification of the predictors in patients at risk of postoperative pain will allow more effective intervention and better management. The coefficient of determination of the predictive models was less than 54%. More vigorous studies with robust statistics and validated designs are needed to investigate this field of interest.

Anatomical study of the innervation of glenohumeral and acromioclavicular joint capsules: implications for image-guided intervention.

BACKGROUND AND OBJECTIVES: In 2011, chronic shoulder joint pain was reported by 18.7 million Americans. Image-guided radiofrequency ablation has emerged as an alternative intervention to manage chronic shoulder joint pain. To optimize the effectiveness of shoulder denervation, it requires a detailed understanding of the nerve supply to the glenohumeral and acromioclavicular joints relative to landmarks visible with image guidance. The purpose of this cadaveric study was to determine the origin, course, relationships to bony landmarks, and frequency of articular branches innervating the glenohumeral and acromioclavicular joints. METHODS: Fifteen cadaveric specimens were meticulously dissected. The origin, course, and termination of articular branches supplying the glenohumeral and acromioclavicular joints were documented. The frequency of each branch was determined and used to generate a frequency map that included their relationships to bony and soft tissue landmarks. RESULTS: In all specimens, the posterosuperior quadrant of the glenohumeral joint was supplied by suprascapular nerve; posteroinferior by posterior division of axillary nerve; anterosuperior by superior nerve to subscapularis; and anteroinferior by main trunk of axillary nerve. Less frequent innervation was found from lateral pectoral nerve and posterior cord. The acromioclavicular joint was found to be innervated by the lateral pectoral and acromial branch of suprascapular nerves in all specimens. Bony and soft tissue landmarks were identified to localize each nerve. CONCLUSIONS: The frequency map of the articular branches supplying the glenohumeral and acromioclavicular joints, as well as their relationship to bony and soft tissue landmarks, provide an anatomical foundation to develop novel shoulder denervation and perioperative pain management protocols.