Image Guidance Technologies for Interventional Pain Procedures: Ultrasound, Fluoroscopy, and CT

Advancements in photoacoustic imaging for cancer diagnosis and treatment

Photoacoustic imaging provides in vivo morphological and functional information about tumors within surrounding tissue. By integrating ultrasound guidance, this technique enables precise localization and characterization of tumors. Moreover, the introduction of targeted contrast agents has further expanded the capabilities of photoacoustic imaging in the realm of in vivo molecular imaging. These contrast agents facilitate enhanced molecular and cellular characterization of cancer, enabling detailed insights into the disease. This review aims to provide a concise summary of the extensive research conducted in the field of Photoacoustic imaging for cancer management. It encompasses the development of the technology, its applications in clinical settings, and the advancements made in molecular imaging. By consolidating and synthesizing the existing knowledge, this review contributes to a better understanding of the potential of photoacoustic imaging in cancer care. In conclusion, photoacoustic imaging has emerged as a non-ionizing and noninvasive modality with the ability to visualize tissue's optical absorption properties while maintaining ultrasound's spatial resolution. Its integration with targeted contrast agents has enhanced molecular and cellular characterization of cancer. This review serves as a succinct overview of the extensive research conducted in the field, shedding light on the potential of photoacoustic imaging in the management of cancer.

Image-guided peripheral nerve interventions- applications and techniques

Interventional radiology continues to be at the forefront of acute and chronic pain management. Our unique imaging expertise and ability to target difficult to reach structures allows for the continuous development of new ways to treat a variety of pain generators. In addition, the advent of thermal ablation techniques and technologies has provided a unique opportunity to offer patients more durable and predictable options to treat their pain. This is particularly important during the opioid epidemic, as multiple local and international governmental bodies push for physicians to create ways to manage pain while reducing the need for long-term opioid dependence. This article aims to review various image-guided techniques and tools for the treatment of pain related to peripheral pain generators, with a focus on the extremities, lumbosacral and pelvic region, and the chest wall. For each target and pathology, we will discuss general etiology, anatomy, procedural approach, and briefly evaluate the supporting literature in each clinical situation.

Lateral pterygoid muscle ultrasound-guided injection: A technical note

BACKGROUND

Temporomandibular disorders (TMDs) are a frequent cause of orofacial pain, causing functional disability and a negative impact on quality of life. Botulinum toxin (BTX-A) injection in lateral pterygoid muscle (LPM) is one of the treatment modalities proposed, but the blind puncture guided by EMG carries a risk of vascular puncture or diffusion of the toxin to nearby muscles. We describe an ultrasound-guided approach and evaluate the spread of the injection in a fresh human cadaver.

METHODS

A fresh human cadaver was injected. An out-of-plane approach was performed using a convex probe, injecting 1.0 ml of 0.25% methylene blue dye into the LPM. After, a dissection was performed to isolate the lateral pterygoid muscle and assess the spread of the dye.

RESULTS

Ultrasound-guided injection allowed to visualize in real-time the spread of the dye within the LPM. The deep and superficial muscles nearby to LPM were not stained by the dye, but upper and lower head of LPM was heavily stained.

CONCLUSION

Ultrasound-guided approach for the injection of BTX-A into the LPM could be considered a successful and safe treatment for myofascial pain related to TMD. Therefore, further clinical studies are needed to study the reproducibility of ultrasound guided LPM injection and to evaluate the clinical results.

Injective Treatments for Sacroiliac Joint Pain: A Systematic Review and Meta-analysis

Background

The most effective injective treatment approach for sacroiliac joint (SIJ) pain remains unclear. Aim of this study was to quantify the safety and effectiveness of the available injective strategies to address SIJ pain.

Methods

A systematic review and meta-analysis of the literature was conducted on PubMed, Scopus, and Embase databases from inception until January 2023. Inclusion criteria were studies written in English, comparative and non-comparative studies regardless of the minimum follow-up, and case series on SIJ injections. Safety and efficacy of the different injection therapies for the SIJ were quantified. A meta-analysis was conducted on the available data of the documented injective therapies. The "Checklist for Measuring Quality" by Downs and Black was used to assess the risk of bias and the quality of papers.

Results

The literature search retrieved 43 papers (2431 patients): 16 retrospective case series, 2 retrospective comparative studies, 17 prospective case series, 3 prospective comparative studies, and 5 randomized controlled trials. Of the selected studies, 63% examined the effect of steroid injections, 16% of PRP injections, while 21% reported other heterogeneous treatments. The failure rate was 26% in steroid injections and 14% in PRP injections. The meta-analysis showed a statistically significant reduction in pain with the VAS score for both steroids and PRP: steroids improvement at mid-term 3.4 points (p < 0.05), at long-term 3.0 (p < 0.05), PRP improvement at mid-term 2.2 (p = 0.007), at long-term 2.3 points of the VAS pain scale (p = 0.02).

Conclusions

Steroids are the most documented injective approach, with studies showing an overall safety and effectiveness. Still, the high number of failures underlined by some studies suggest the need for alternative procedures. Early PRP data showed promise, but the limitations of the current literature do not allow to clearly define the most suitable injective approach, and further studies are needed to identify the best injective treatment for SIJ patients.

The challenge of pharmacotherapy for musculoskeletal pain: an overview of unmet needs

Musculoskeletal disorders are characterized by several impairments, including pain, affecting muscles, bones, joints and adjacent connective tissue, resulting in temporary or permanent functional limitations and disability. Musculoskeletal pain is particularly prevalent worldwide and greatly impacts the quality of life, social participation and economic burden. To date, several issues persist about the classification of musculoskeletal pain and its management strategies and resources. The treatment of musculoskeletal pain conditions is complex and often requires a multimodal approach, including pharmacological and non-pharmacological therapy that might be ineffective in many cases, resulting in poor patient satisfaction and controversial expectations about the potential benefits of available interventions. This manuscript provides an overview of unmet needs in managing musculoskeletal pain, particularly focusing on pharmacotherapeutic pitfalls in this context.

Extended reality navigation for pain procedures: a narrative review

BACKGROUND

Extended reality (XR) technology, encompassing virtual reality, augmented reality, and mixed reality, has been widely studied for procedural navigation in surgical specialties. Similar to how ultrasound transformed regional anesthesia, XR has the potential to reshape how anesthesiologists and pain physicians perform procedures to relieve pain.

OBJECTIVE

This narrative review examines the clinical benefits of XR for navigation in various pain procedures. It defines key terms and concepts related to XR technology and explores characteristics of procedures that are most amenable to XR-based navigation. Finally, it suggests best practices for developing XR navigation systems and discusses the role of emerging technology in the future of XR in regional anesthesia and pain medicine.

EVIDENCE REVIEW

A search was performed across PubMed, Embase, and Cochrane Central Register of Controlled Trials for primary literature investigating the clinical benefits of XR navigation for pain procedures.

FINDINGS

Thirteen studies using XR for procedural navigation are included. The evidence includes randomized controlled trials, retrospective studies, and case series.

CONCLUSIONS

Early randomized controlled trials show potential for XR to improve procedural efficiency, but more comprehensive research is needed to determine if there are significant clinical benefits. Case reports demonstrate XR's utility in generating patient-specific navigation plans when difficult anatomy is encountered. Procedures that facilitate the generation and registration of XR images are most conducive to XR navigation, whereas those that rely on frequent re-imaging will continue to depend on traditional modes of navigation.

Deep Learning Detection and Segmentation of Facet Joints in Ultrasound Images Based on Convolutional Neural Networks and Enhanced Data Annotation

The facet joint injection is the most common procedure used to release lower back pain. In this paper, we proposed a deep learning method for detecting and segmenting facet joints in ultrasound images based on convolutional neural networks (CNNs) and enhanced data annotation. In the enhanced data annotation, a facet joint was considered as the first target and the ventral complex as the second target to improve the capability of CNNs in recognizing the facet joint. A total of 300 cases of patients undergoing pain treatment were included. The ultrasound images were captured and labeled by two professional anesthesiologists, and then augmented to train a deep learning model based on the Mask Region-based CNN (Mask R-CNN). The performance of the deep learning model was evaluated using the average precision (AP) on the testing sets. The data augmentation and data annotation methods were found to improve the AP. The AP50 for facet joint detection and segmentation was 90.4% and 85.0%, respectively, demonstrating the satisfying performance of the deep learning model. We presented a deep learning method for facet joint detection and segmentation in ultrasound images based on enhanced data annotation and the Mask R-CNN. The feasibility and potential of deep learning techniques in facet joint ultrasound image analysis have been demonstrated.

Guidance of Nerve Stimulator and Ultrasound for Transforaminal Epidural Steroid Injection in Lumbosacral Radicular Pain : A Single Institution Experience in Vietnam

OBJECTIVE

This study aimed to evaluate the clinical feasibility of the combination of ultrasound and nerve stimulator guidance in transforaminal epidural steroid injections (TESIs) to manage lumbosacral chronic radicular pain.

METHODS

Using the combination of nerve stimulator and ultrasound guidance, TESIs were performed in 125 segments of 78 patients who presented with chronic lumbar radicular pain. Demographic characteristics and surgical outcomes were recorded on admission, pre-procedural and post-procedural for 1-week, 1-month, 3-month, and 6-month follow-ups. The result was measured using the Numeric rating scale (NRS) and Oswestry disability index (ODI).

RESULTS

Patients who received TESIs showed significant improvements on two evaluation tools (NRS, ODI), compared to that before procedure (p<0.001). No significant complications were observed for 6 months' follow-up.

CONCLUSION

The result suggests that a combination of ultrasound and nerve stimulator guidance in transforaminal epidural injections is safe, reliable and effective for short-term management of lumbar disc herniation. It is a promising technique and has shown good results in providing intermediate pain relief.

Ultrasound-guided and CT-guided selective cervical nerve root injection for the treatment of cervical radicular pain: A retrospective clinical study

OBJECTIVE

To compare the clinical effects and safety of ultrasound (US)-guided selective cervical nerve root injection (SCNI) and computed tomography (CT)-guided SCNI for patients with cervical radicular pain (CRP).

METHODS

Forty-two CT-guided SCNI procedures (26 eligible patients) and forty-two US-guided SCNI procedures (25 eligible patients) performed to treat CRP were identified from the medical record system between October 2017 and July 2021 and enrolled in the study. The numeric rating scale was used to assess pre- and postprocedural pain levels, and the neck disability index was used to assess the level of function. All immediate and delayed clinical complications were also recorded. The cost of each procedure and the radiation dose of the CT procedure were documented. The follow-up data were obtained by telephone calls or outpatient visits.

RESULTS

Five patients in the CT group and one patient in the US group were lost to follow-up at 1 year. No procedure-related complications were observed in either group. Significant pain relief and cervical function improvement were achieved after treatment in both the CT-guided SCNI and US-guided SCNI groups; however, there were no significant differences between the two groups. The average cost per CT-guided SCNI procedure was 133.2 USD, which was higher than the cost per US-guided SCNI procedure (42.2 USD). Meanwhile, the necessary radiation dose per patient in the CT group was 0.36 ± 0.08 mGy.

CONCLUSIONS

US-guided SCNI and CT-guided SCNI have similar efficacy in treating CRP, but US-guided SCNI is radiation free and less costly than the CT-guided procedure.

Erector spinae plane block versus local infiltration anaesthesia for transforaminal percutaneous endoscopic discectomy: A prospective randomised controlled trial

BACKGROUND

Around 60%-80% of the population suffers from back pain, making it one of the most common health complaints. Transforaminal percutaneous endoscopic discectomy (TPED) is an effective treatment for low back pain that can be performed using different anaesthesia techniques. Our primary objective was to test the hypothesis that bilateral Erector spinae plane block (ESP) plus sedation is equally effective as traditional local infiltration anaesthesia plus sedation in TPED.

MATERIALS AND METHODS

Fifty-two patients undergoing TPED were randomly assigned to 2 groups: G1 - intravenous sedation with local infiltration anaesthesia; G2 - intravenous sedation with bilateral ESP.

PRIMARY OUTCOME

volume of fentanyl and propofol administered during surgery.

SECONDARY OUTCOMES

adverse events during sedation reported using the World Society of Intravenous Anaesthesia (SIVA) adverse sedation event tool, level of postoperative sedation measured on the Richmond Agitation-Sedation Scale (RASS), intensity of postoperative pain on a visual analogue scale (VAS), mechanical pain threshold (MPT) measured with von Frey monofilaments on both lower extremities, patient satisfaction with analgesia on 5-point Likert scale.

RESULTS

Volume of fentanyl, propofol, and level of postoperative sedation was significantly lower in G2 (p < 0.001). There was no difference between groups in intensity of pain, patient satisfaction with analgesia, and mechanical pain threshold after surgery. There were no adverse events in G2, but in G1 2 patients presented minimal risk descriptors, 5 presented minor risk descriptors, and 1 presented sentinel risk descriptors that required additional medication or rescue ventilation.

CONCLUSIONS

The ESP was equal to local infiltration anaesthesia in terms of intensity of pain, mechanical pain threshold after surgery, and patient satisfaction; however, ESP reduced the volume of intraoperative fentanyl and propofol, thereby reducing the adverse effects of sedation.

Ultrasound-Guided vs. Fluoroscopy-Guided Interventions for Back Pain Management: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The objective of this study was to compare the outcomes of the ultrasound- and fluoroscopy-guided techniques in the management of back pain. Using PubMed, Scopus, and the Cochrane Library, we searched randomized controlled trials (RCTs) published before May 2023, which reported relevant data on the topic. The effectiveness of the ultrasound-guided (US-guided) and fluoroscopy-guided (FL-guided) approaches for back pain management was compared in terms of postoperative pain intensity, postoperative functional outcomes, and postoperative complications. Subgroup analyses were conducted for different postoperative periods. Eight studies were included in the analysis. There was no significant difference in post-procedural pain relief at one week, two weeks, one month, two months, and three months between the US-guided and FL-guided interventions for back pain management (SMD with 95% CI is -0.01 [-0.11, 0.10]), p = 0.91, I2 = 0%). In terms of the postoperative functional outcomes assessed by the "Oswestry Disability Index" (ODI) functionality score, the model tends to favor the FL-guided injections over the US-guided injections (SMD with 95% CI: 0.13 [-0.00, 0.25], p = 0.05, I2 = 0). Finally, the US-guided and FL-guided injections did not show significantly different results in terms of postoperative complications (RR with 95% CI is 0.99 [0.49, 1.99], p = 0.97, I2 = 0). The subgroup analysis also did not demonstrate differences between the US-guided and FL-guided techniques in the following outcomes: vasovagal reaction, transient headache, and facial flushing. There was no significant difference between the US-guided and FL-guided injections for treating back pain in terms of postoperative pain intensity and complications. Still, the model tends to favor the FL-guided injections over the US-guided injections in terms of functionality.

Pain Education and Knowledge (PEAK) Consensus Guidelines for Neuromodulation: A Proposal for Standardization in Fellowship and Training Programs

The need to be competent in neuromodulation is and should be a prerequisite prior to completing a fellowship in interventional pain medicine. Unfortunately, many programs lack acceptable candidates for these advanced therapies, and fellows may not receive adequate exposure to neuromodulation procedures. The American Society of Pain and Neuroscience (ASPN) desires to create a consensus of experts to set a minimum standard of competence for neurostimulation procedures, including spinal cord stimulation (SCS), dorsal root ganglion stimulation (DRG-S), and peripheral nerve stimulation (PNS). The executive board of ASPN accepted nominations for colleagues with excellence in the subject matter of neuromodulation and physician education. This diverse group used peer-reviewed literature and, based on grading of evidence and expert opinion, developed critical consensus guides for training that all accredited fellowship programs should adopt. For each consensus point, transparency and recusal were used to eliminate bias, and an author was nominated for evidence grading oversight and bias control. Pain Education and Knowledge (PEAK) Consensus Guidelines for Neuromodulation sets a standard for neuromodulation training in pain fellowship training programs. The consensus panel has determined several recommendations to improve care in the United States for patients undergoing neuromodulation. As neuromodulation training in the United States has evolved dramatically, these therapies have become ubiquitous in pain medicine. Unfortunately, fellowship programs and the Accreditation Council for Graduate Medical Education (ACGME) pain program requirements have not progressed training to match the demands of modern advancements. PEAK sets a new standard for fellowship training and presents thirteen practice areas vital for physician competence in neuromodulation.

Interventional Pain Procedures: A Narrative Review Focusing on Safety and Complications. Part 1 Injections for Spinal Pain

In recent years, there has been a considerable increase in the number of image-guided interventional procedures performed for the management of acute and chronic pain. Concomitantly, there has also been an increase in the complication rate related to these procedures. The aim of this narrative review is to summarize the primary complications associated with commonly performed image-guided (fluoroscopic- or ultrasound-guided) interventional procedures. 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.

Augmented Reality-Assisted Navigation System for Transforaminal Epidural Injection

Purpose

Multiple studies have attempted to demonstrate the benefits of augmented reality (AR)-assisted navigation systems in surgery. Lumbosacral transforaminal epidural injection is an effective treatment commonly used in patients with radiculopathy due to spinal degenerative pathologies. However, few studies have applied AR-assisted navigation systems to this procedure. The study aimed to investigate the safety and effectiveness of an AR-assisted navigation system for transforaminal epidural injection.

Patients and Methods

Through a real-time tracking system and a wireless network to the head-mounted display, computed tomography images of the spine and the path of a spinal needle to the target were visualized on a torso phantom with respiration movements installed. From L1/L2 to L5/S1, needle insertions were performed using an AR-assisted system on the left side of the phantom, and the conventional method was performed on the right side.

Results

The procedure duration was approximately three times shorter, and the number of radiographs required was reduced in the experimental group compared to the control group. The distance from the needle tips to the target areas in the plan showed no significant difference between the two groups. (AR group 1.7 ± 2.3mm, control group 3.2 ± 2.8mm, P value 0.067).

Conclusion

An AR-assisted navigation system may be used to reduce the time required for spinal interventions and ensure the safety of patients and physicians in view of radiation exposure. Further studies are essential to apply AR-assisted navigation systems to spine interventions.

Subfascial versus extrafascial ultrasound-guided stellate ganglion block in patients with post-mastectomy sympathetically mediated pain: A randomized clinical trial

Background

Despite being a well-described intervention, the optimal anatomical approach to perform a stellate ganglion block (SGB) has been disputed. We compared the subfascial and extrafascial ultrasound-guided (USG) SGB.

Methods

A randomised clinical trial was conducted, consisting of 50 patients in two groups. Group I received SGB via the subfascial approach while Group II received an SGB via the extrafascial approach. The primary endpoint was successful sympathetic blockade (as indicated by a measured temperature rise of ≥2°C). Secondary endpoints included analgesic efficiency (extent of early onset of pain relief as indicated by >50% improvement in Visual Analogue Scale (VAS) score at 300's post-procedure); occurrence of Horner's syndrome; extent of local anaesthetic distribution; and adverse events.

Results

The mean increase in sympathetic blockade was significantly higher in the subfascial group (2.6 ± 0.6°C; p = .003). Analgesic efficacy was also significantly higher in the subfascial group (p < .001). The difference in the average dermatomal spread of local anaesthetic down to T2 and up to C4 between the groups was also statistically significant (p = .021 and p = .019, respectively).

Conclusions

The degree of temperature rise, pain relief and occurrence of Horner's syndrome were higher in the subfascial than the extrafascial group. The subfascial approach to SGB, with a limited volume of local anaesthetic agent, is a more reliable technique when compared to the extrafascial approach.

Anatomical study and clinical significance of the posterior ramus of the spinal nerve of the lumbar spine

Background and objectives: Chronic nonspecific back pain is a common clinical disease typically treated by ultrasound-guided spinal injection. This minimally invasive treatment targets the posterior ramus of the spinal nerve (PRSN). The target of the medial branch is clear, but there is unclear target for the intermediate and lateral branches. This study attempted to observe the distribution of PRSN in the dorsal region of transverse process to provide a more detailed anatomical basis for treating spinal pain.

Methods: The present study was conducted on 16 transverse processes of six adult male embalmed corpses. The dorsal area of the transverse process was divided into three equal zones, which are zone I, zone II and zone III from inside to outside. The origin, distribution, quantity, transverse diameter, and relationship with the bone structure of the PRSN on the transverse process were observed.

Results: Sixty PRSNs were found in the lumbar of six cadavers, of which 48 were divided into three branches, and 12 PRSNs were divided into two branches. The intermediate branch is mainly distributed in zone I, and the lateral branch is mainly distributed in zone II. Twenty-nine communicating branches were found in 48 adjacent segments of six specimens, all of which originated from the intermediate branch of the previous segment and connected with the lateral branch of the next segment.

Conclusion: This anatomical study describing the PRSN may have important clinical significance for spinal surgeons. Understanding the bony localization targets of the PRSN and the links between the PRSNs may benefit patients with low back pain who receive spinal injections.

Image-guided intratumoral immunotherapy: Developing a clinically practical technology

Immunotherapy has revolutionized the contemporary oncology landscape, with durable responses possible across a range of cancer types. However, the majority of cancer patients do not respond to immunotherapy due to numerous immunosuppressive barriers. Efforts to overcome these barriers and increase systemic immunotherapy efficacy have sparked interest in the local intratumoral delivery of immune stimulants to activate the local immune response and subsequently drive systemic tumor immunity. While clinical evaluation of many therapeutic candidates is ongoing, development is hindered by a lack of imaging confirmation of local delivery, insufficient intratumoral drug distribution, and a need for repeated injections. The use of polymeric drug delivery systems, which have been widely used as platforms for both image guidance and controlled drug release, holds promise for delivery of intratumoral immunoadjuvants and the development of an in situ cancer vaccine for patients with metastatic cancer. In this review, we explore the current state of the field for intratumoral delivery and methods for optimizing controlled drug release, as well as practical considerations for drug delivery design to be optimized for clinical image guided delivery particularly by CT and ultrasound.

Stellate ganglion intervention for chronic pain: A review

Stellate ganglion (SG) intervention is currently widely being studied in many kinds of chronic pain. As one of the convenient ways to treat the sympathetic nervous system, the indications for stellate ganglion intervention (SGI) include complex regional pain syndrome, postherpetic neuralgia, cancer pain of different origins, orofacial pain, and so forth. SGI refers to the reversible or irreversible blocking of the cervical sympathetic trunk, cervical sympathetic ganglion, and their innervation range through noninvasive or minimally invasive treatment. Current treatment options include stellate ganglion block (SGB), SG pulsed radiofrequency, continuous radiofrequency treatment, and noninvasive SGB. In particular, SGB continues to be one of the most studied methods in chronic pain management. However, a single SGB usually provides only short-term effects; repeated SGB may result in complications such as hoarseness, light-headedness, and vessel or nerve injury. Meanwhile, the mechanism of SGI is still unclear. This review discusses the research progress of SGI methods, effectiveness, complications, and possible mechanisms in the management of chronic pain.

Evaluation of contrast-enhanced ultrasonography with Sonazoid® in visualization of local anesthetic distribution in rectus sheath block: a prospective, clinical study

PURPOSE

Clear visualization of ultrasound (US) images is crucial for successful US-guided nerve block. However, accurate determination of local anesthetic (LA) distribution from US images remains difficult. Sonazoid^®, which comprises perflubutane microbubbles, is used to diagnose hepatic and breast tumors. This study aimed to investigate the visibility of Sonazoid^® in perioperative US-guided nerve block.

METHODS

We performed rectus sheath block (RSB) in patients scheduled for laparoscopic abdominal surgery (n = 10). 10 mL of a mixture containing equal amounts of 0.75% ropivacaine and iohexol with the addition of Sonazoid^® diluted 100-fold was administered. We investigated the correlation and agreement between Sonazoid^® and iohexol distributions. The brightness of the solution and tissues was calculated: a grayscale value between 0 (dark) and 255 (bright) was measured in all pixels of the region of interest. Adverse events were also investigated.

RESULTS

Sonazoid^® was clearly visualized and distinguished from the surrounding tissues both during and after RSB. The spread of Sonazoid® and iohexol was significantly correlated (spearman's ρ = 0.53, p = 0.0004). Bland-Altman analyses revealed significant mean difference between two methods (15.6 mm; 95% confidence interval [CI]: 10.6, 20.6; standard deviation (SD) 15.65; p < 0.0001). Limits of agreement were - 14.94 to 46.24 mm. Sonazoid^® significantly increased the mean grayscale values at the posterior rectus sheath (93.7 vs. 201.9, p < 0.0001). There were no complications.

CONCLUSION

Sonazoid diluted 100-fold^® was clearly visualized real-time, and the enhancement was sustained and measurable after RSB. Sonazoid^® could potentially be used for the contrast agent of US-guided nerve block.

Review of Sacroiliac Joint Injection Techniques

PURPOSE OF REVIEW

The purpose of the review is to evaluate the current evidence on techniques for sacroiliac joint (SIJ) injections using landmark, ultrasound, fluoroscopy, and computed tomography (CT) guidance.

METHODS

A literature search was performed to find all relevant retrospective, prospective, and randomized controlled (RCT) studies where SIJ injections were performed under ultrasound, fluoroscopy, and CT guidance.

RECENT FINDINGS

A total of eight studies were identified with suitable data for inclusion. There were two RCTs, four prospective, and two retrospective studies included. Case reports or case series were excluded. A total of 420 patients were enrolled across all eight studies. CT guidance provided the most accurate needle placement in the SIJ injections followed by fluoroscopy, which was more accurate than ultrasound. Landmark-guided injections were not accurate. Accurate needle placement in SIJ confirms SIJ-mediated pain and injection of corticosteroids leads to improvement in pain and/or disability outcome measures regardless of guidance technique. Diagnostic CT-guided SIJ injections should be performed prior to consideration of SIJ fusion.

Therapy of Neurophysiological Changes after Oral and Maxillofacial Surgery—A Systematic Review

Introduction: The purpose of this systematic review was to critically analyze the recent literature to present a guideline for management of neurophysiological changes after implant placement and oral and maxillofacial surgical procedures. Materials and methods: Three electronic databases and manual search approaches were used to identify relevant articles on neurophysiological changes. Only studies with a randomized controlled study design were included. Primary outcome was defined as the status of recovery and relief of pain states under various therapies. Two independent reviewers evaluated the data. Results: A total of eight studies from 2891 records identified met the inclusion criteria. Therapy options for patients with neurophysiological changes after implant placement and oral and maxillofacial surgery were low-level laser (LLL), stellate ganglion block (SGB), medication, and surgical removal of implants. Six studies dealt with LLL, providing a significant improvement in mechanical sensation. Only one study revealed the whole neurosensory profile including neuropathic pain states. All the included RCT studies presented at least one bias, and a considerable heterogeneity of the included studies was revealed. Conclusions: Reduced thermal sensation may be due to irritation of small fibers. LLL might help to improve nerve recovery.

Creation of a three-dimensional printed spine model for training in pain procedures

OBJECTIVE

Technological developments have made it possible to create simulation models to educate clinicians on surgical techniques and patient preparation. In this study, we created an inexpensive lumbar spine phantom using patient data and analyzed its usefulness in clinical education.

METHODS

This randomized comparative study used computed tomography and magnetic resonance imaging data from a single patient to print a three-dimensional (3D) bone framework and create a mold. The printed bones and structures made from the mold were placed in a simulation model that was used to train residents. The residents were divided into two groups: Group L, which received only an audiovisual lecture, and Group P, which received an additional 1 hour of training using the 3D phantom. The performance of both groups was evaluated using pretest and post-test analyses.

RESULTS

Both the checklist and global rating scores increased after training in both groups. However, some variables improved significantly only in Group P. The overall satisfaction score was also higher in Group P than in Group L.

CONCLUSIONS

We have described a method by which medical doctors can create a spine simulation phantom and have demonstrated its efficiency for procedural education.

A Review of Techniques of Intercostal Nerve Blocks

PURPOSE OF REVIEW

Intercostal nerve blocks are indicated for multiple chronic pain and acute pain conditions including rib fractures, herpes zoster, post-thoracotomy pain syndrome, and intercostal neuralgia. Intercostal neuralgia is a type of neuropathic pain that is in the distribution of intercostal nerves. The purpose of this review is to evaluate the different techniques used to perform intercostal nerve blocks and review their efficacy and safety including blind technique using anatomical landmarks, and fluoroscopically guided and ultrasound-guided intercostal nerve blocks.

RECENT FINDINGS

Literature search was performed with the keywords including intercostal neuralgia, treatment, intercostal nerve blocks, and radiofrequency ablation on PubMed and Google Scholar. Three studies and one case report were identified. Literature review revealed that ultrasound-guided techniques and fluoroscopically guided techniques are superior to landmark-based technique in terms of efficacy. There was no difference in efficacy and complication rates between ultrasound and fluoroscopic guidance. Ultrasound-guided techniques and fluoroscopically guided techniques can both be performed safely and effectively for various chronic pain conditions. Ultrasound guidance has its advantages of direct visualization of nerves, vessels, muscles, and the lung. It is potentially a superior technique in terms of improving accuracy and decreasing complications. Further large population randomized control studies should be conducted to compare the efficacy of intercostal nerve blocks performed under ultrasound and fluoroscopy.

Magnetic resonance imaging validation of medial transthyroid ultrasound-guided stellate ganglion block: A pilot study

OBJECTIVE

Ultrasound-guided stellate ganglion block (usSGB) facilitates improved accuracy of needle position and application of lesser volumes of local anesthetic (LA). Approaches of usSGB, however, have not fully been optimized with respect to efficacy and technical convenience. This pilot study examined the anatomical position and spatial distribution of a small volume of LA injectate dispensed by medial transthyroid usSGB via magnetic resonance imaging (MRI) and assessment of its effect on cervical sympathetic nerves.

METHODS

Twelve healthy males were tested in a double-blinded within-subject design. In a total of 37 usSGB, 3 ml of LA and saline 0.9% solution were injected intramuscularly into the longus colli muscle (LCM) preventing uncontrollable spread of LA within cervical structures. Immediately after injection, distribution of injectate was traced by MRI. Twenty-four out of the 37 usSGB-injections with 3 ml ropivacaine 1% (verum) and saline 0.9% (placebo) were compared. Efficacy of usSGB was assessed by the appearance of oculosympathetic paresis and increases in skin temperature.

RESULTS

All usSGBs were positioned in the proximity of the LCM muscle belly. Most of the axial injectate was distributed within the transversal plane between the middle section of C5 and the upper section of T1 vertebra. Signs of oculosympathetic paresis and skin temperature increase were found exclusively under verum conditions.

CONCLUSION

This pilot study demonstrated the feasibility of medial transthyroid usSGB using an out-of-plane technique and a volume of 3 ml of LA. Further studies are required to establish the relative value and safety of this technique compared to other published approaches.

New ultrasound-guided techniques in chronic pain management: an update

PURPOSE OF REVIEW

The introduction of ultrasound guidance in interventional pain management leads to the development of new interventional pain management techniques. Ultrasound-guided (UG) interventional pain management is rapidly developing and increasingly more commonly used, due to its many advantages over traditional radiologic imaging modalities. This review will summarize recent literature around novel interventional pain techniques with ultrasound guidance published over the last 18 months.

RECENT FINDINGS

Many new interventional pain management methods have been described in the last few years in the literature. The use of ultrasonography in interventional pain management played a crucial role in these developments. This review includes newly described interventional methods in the literature. The review particularly focussed on the methods that are used to treat the pain in the hip, shoulder, knee, and lumbar area. These new techniques hold promise for significant improvements in the efficacy and safety of interventional pain management.

SUMMARY

There have been many innovations in UG interventional procedures, however, some of them require more rigorous validation before their widespread use.

(4-Aminopyridine)-PLGA-PEG as a Novel Thermosensitive and Locally Injectable Treatment for Acute Peripheral Nerve Injury

Traumatic peripheral nerve injury (TPNI) represents a major medical problem that results in loss of motor and sensory function, and in severe cases, limb paralysis and amputation. To date, there are no effective treatments beyond surgery in selective cases. In repurposing studies, we found that daily systemic administration of the FDA-approved drug 4-aminopyridine (4-AP) enhanced functional recovery after acute peripheral nerve injury. This study was aimed at constructing a novel local delivery system of 4-AP using thermogelling polymers. We optimized a thermosensitive (4-AP)-poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) block copolymer formulation. (4-AP)-PLGA-PEG exhibited controlled release of 4-AP both in vitro and in vivo for approximately 3 weeks, with clinically relevant safe serum levels in animals. Rheological investigation showed that (4-AP)-PLGA-PEG underwent a solution to gel transition at 32 °C, a physiologically relevant temperature, allowing us to administer it to an injured limb while subsequently forming an in situ gel. A single local administration of (4-AP)-PLGA-PEG remarkably enhanced motor and sensory functional recovery on post-sciatic nerve crush injury days 1, 3, 7, 14, and 21. Moreover, immunohistochemical studies of injured nerves treated with (4-AP)-PLGA-PEG demonstrated an increased expression of neurofilament heavy chain (NF-H) and myelin protein zero (MPZ) proteins, two major markers of nerve regeneration. These findings demonstrate that (4-AP)-PLGA-PEG may be a promising long-acting local therapeutic agent in TPNI, for which no pharmacologic treatment exists.

Chinese Association for the Study of Pain: Experts consensus on ultrasound-guided injections for the treatment of spinal pain in China (2020 edition)

Spinal pain (SP) is a common condition that has a major negative impact on a patient’s quality of life. Recent developments in ultrasound-guided injections for the treatment of SP are increasingly being used in clinical practice. This clinical expert consensus describes the purpose, significance, implementation methods, indications, contraindications, and techniques of ultrasound-guided injections. This consensus offers a practical reference point for physicians to implement successfully ultrasound-guided injections in the treatment of chronic SP.

Stellate ganglion block combined with intra-arterial treatment: a "one-stop shop" for cerebral vasospasm after aneurysmal subarachnoid hemorrhage-a pilot study

PURPOSE

Delayed cerebral ischemia (DCI) is a frequent cause of morbidity and mortality in patients with cerebral vasospasm (CV) following aneurysmal subarachnoid hemorrhage (aSAH). Refractory CV remains challenging to treat and often leads to permanent deficits and death despite aggressive therapy. We hereby report the feasibility and safety of stellate ganglion block (SGB) performed with a vascular roadmap-guided technique to minimize the risk of accidental vascular puncture and may be coupled to a diagnostic or therapeutic cerebral angiography.

METHODS

In addition to a detailed description of the technique, we performed a retrospective analysis of a series of consecutive patients with refractory CV after aSAH that were treated with adjuvant roadmap-guided SGB. Clinical outcomes at discharge are reported.

RESULTS

Nineteen SGB procedures were performed in 10 patients, after failure of traditional hemodynamic and endovascular treatments. Each patient received 1 to 3 SGB, usually interspaced by 24 h. In 4 patients, an indwelling microcatheter for continuous infusion was inserted. First SGB occurred on average 7.3 days after aSAH. SGB was coupled to intra-arterial nimodipine infusion or balloon angioplasty in 9 patients. SGB was technically successful in all patients. There were no technical or clinical complications.

CONCLUSION

Adjuvant SGB may be coupled to endovascular therapy to treat refractory cerebral vasopasm within the same session. To guide needle placement, using a roadmap of the supra-aortic arteries may decrease the risk of complications. More prospective data is needed to evaluate the therapeutic efficacy, durability, and safety of SGB compared with the established standard of care.

Ultrasound-Guided Neuraxial Anesthesia

PURPOSE OF REVIEW

There has been a recent surge of interest in clinical applications of ultrasound, which has revolutionized acute pain management. This review is to summarize the current status of ultrasound utilization in neuraxial anesthesia, the most common type of regional anesthesia.

RECENT FINDINGS

Ultrasound-assisted and ultrasound-guided neuraxial anesthesia has improved clinical accuracy and patient safety through landmark identification including proper vertebral level and midline, as well as via measurements on neuraxial space. Direct needle or catheter visualization during the entire procedure has not yet been achieved consistently. The recent introduction of ultrasound into neural anesthesia has clinical performance benefits and patient safety implications, with documented improvement on overall efficacy with higher first attempt success rate as well as less needle pass. More controlled studies are needed for the overall impact of ultrasonography in neuraxial anesthesia in obstetric and non-obstetric patients.

Consensus practice guidelines on interventions for lumbar facet joint pain from a multispecialty, international working group

BACKGROUND

The past two decades have witnessed a surge in the use of lumbar facet blocks and radiofrequency ablation (RFA) to treat low back pain (LBP), yet nearly all aspects of the procedures remain controversial.

METHODS

After approval by the Board of Directors of the American Society of Regional Anesthesia and Pain Medicine, letters were sent to a dozen pain societies, as well as representatives from the US Departments of Veterans Affairs and Defense. A steering committee was convened to select preliminary questions, which were revised by the full committee. Questions were assigned to 4-5 person modules, who worked with the Subcommittee Lead and Committee Chair on preliminary versions, which were sent to the full committee. We used a modified Delphi method, whereby the questions were sent to the committee en bloc and comments were returned in a non-blinded fashion to the Chair, who incorporated the comments and sent out revised versions until consensus was reached.

RESULTS

17 questions were selected for guideline development, with 100% consensus achieved by committee members on all topics. All societies except for one approved every recommendation, with one society dissenting on two questions (number of blocks and cut-off for a positive block before RFA), but approving the document. Specific questions that were addressed included the value of history and physical examination in selecting patients for blocks, the value of imaging in patient selection, whether conservative treatment should be used before injections, whether imaging is necessary for block performance, the diagnostic and prognostic value of medial branch blocks (MBB) and intra-articular (IA) injections, the effects of sedation and injectate volume on validity, whether facet blocks have therapeutic value, what the ideal cut-off value is for a prognostic block, how many blocks should be performed before RFA, how electrodes should be oriented, the evidence for larger lesions, whether stimulation should be used before RFA, ways to mitigate complications, if different standards should be applied to clinical practice and clinical trials and the evidence for repeating RFA (see table 12 for summary).

CONCLUSIONS

Lumbar medial branch RFA may provide benefit to well-selected individuals, with MBB being more predictive than IA injections. More stringent selection criteria are likely to improve denervation outcomes, but at the expense of more false-negatives. Clinical trials should be tailored based on objectives, and selection criteria for some may be more stringent than what is ideal in clinical practice.

Percutaneous imaging-guided techniques for the treatment of benign neuropathic pain

To date, conservative management including physical and/or systemic pharmacologic therapy is considered as the first line approach for the management of neuropathic pain syndromes. In the era of an opioid overdose crisis with an increased concern upon the risks and harms arising from the misuse of medicines for pain management, percutaneous minimally invasive techniques such as nerve infiltrations as well as neurolysis or neuromodulation techniques can be proposed to control pain and improve life quality. Computed tomography can serve as an ideal guiding technique due to its specific characteristics including precise anatomic delineation, high spatial resolution and good tissue contrast. The purpose of this review is to make the reader familiar with the most common indications for minimally invasive imaging-guided techniques in patients with neuralgia and provide current evidence regarding technical considerations.

Value of ultrasound-guided transforaminal nerve block in the treatment of lumbar disc herniation

Objective

This study was performed to investigate the effectiveness and safety of ultrasound-guided transforaminal nerve block in the treatment of lumbar disc herniation.

Methods

Sixty patients who underwent treatment for protrusion of a lumbar intervertebral disc in Wangjing Hospital from January 2016 to December 2017 were divided into the study group and the control group. The visual analog scale (VAS) pain scores, the Japanese Orthopaedic Association (JOA) scores of the lumbar vertebra, PRI (pain rating index), and PPI (present pain intensity) were recorded at 30 minutes, 1 week, and 3 months after the operation.

Results

There were significant differences in the VAS, JOA, PRI, and PPI scores between the study group and control group.

Conclusion

Ultrasound guidance can improve the efficacy and safety of transforaminal nerve block in the treatment of lumbar disc herniation and shorten the operative duration.