Is Ultrasound Guidance Advantageous for Interventional Pain Management? A Systematic Review of Chronic Pain Outcomes

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.

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.

Analgesic effect of perineural local anesthetics, steroids, and conventional medical management for trauma and compression-related peripheral neuropathic pain: a retrospective cohort study

INTRODUCTION

Trauma and compression are common causes of peripheral neuropathic pain (NP) refractory to conventional medical management (CMM). The role of perineural interventions in relieving this type of pain is unclear.

OBJECTIVES

The objectives of this retrospective study were to determine the analgesic benefits of adding a combination of perineural local anesthetic and steroids (LA-S) to CMM compared with CMM alone in patients who had moderate-to-severe refractory NP after trauma to the ankle and the foot.

METHODS

Health care records of 60 patients in exposed (3 injections of perineural LA-S at weekly intervals with CMM) and 60 in unexposed (CMM) cohorts were reviewed. Data on patient characteristics, pain, and mental and physical function were extracted at baseline and at the postintervention follow-up. Data were analyzed to evaluate analgesic benefit from the study interventions and the impact of baseline characteristics.

RESULTS

Perineural LA-S with CMM cohort had lower pain numerical rating scale scores at 1 to 3 months after the intervention as compared to the CMM alone cohort (5.50 [interquartile range 4.00-7.00] and 7.00 [interquartile range 5.00-8.00], respectively; P < 0.01). However, multivariable analysis did not show an independent beneficial analgesic effect with the addition of perineural LA-S to CMM compared with CMM alone. A greater severity of preintervention catastrophizing (each unit increase in pain catastrophizing score increased pain score at follow-up by 0.04, 95% confidence interval: 0.01-0.07) was associated with reduction in the analgesic benefit.

CONCLUSION

Perineural local anesthetic and steroid injections do not confer an analgesic benefit for trauma- or compression-related peripheral NP.

Ultrasound-guided interventions during pregnancy for lumbosacral pain unresponsive to conservative treatment: A retrospective review

PURPOSE

Current conventional therapeutic strategies for lumbosacral pain during pregnancy are usually inadequate and data regarding interventional analgesic procedures feasible in pregnant women is scarce. We decided to retrospectively review our experience of ultrasound-guided pain management procedures in pregnant women with lumbosacral pain unresponsive to conservative treatment.

METHODS

Twenty women in the second trimester of pregnancy with lumbosacral pain developed during pregnancy unresponsive to conservative treatments who underwent the following ultrasound-guided pain interventions were included: sacroiliac joint, caudal epidural, interlaminar epidural, and trigger point injections. All patients were followed up until early postnatal period using Visual Analogue Scale (VAS) and Oswestry Disability Index (ODI) scores.

RESULTS

All but one patient achieved satisfactory pain control throughout the pregnancy with a single injection. Significant declines in ODI and VAS scores was attained within the first 2 weeks and first week of intervention, respectively, which was maintained thereafter until early postnatal period.

CONCLUSIONS

Injections used for effective interventional pain management in nonpregnant populations seem to represent an effective and safe method also for pregnant women when performed under ultrasound guidance, with rapid onset and enduring duration of action until the time of delivery.

Neuropatía del pudendo como causa de dolor pélvico

El síndrome de atrapamiento del nervio pudendo es una de múltiples causas de dolor pélvico crónico. Hemos realizado una revisión de la literatura sobre su presentación clínica, diagnóstico y tratamiento, con el propósito de conocer los detalles más relevantes de una enfermedad que cada vez está siendo más diagnosticada, con el fin de realizar un abordaje precoz desde un punto de vista integral.

Perineural steroid injections around ilioinguinal, iliohypogastric, and genitofemoral nerves for treatment of chronic refractory neuropathic pain: A retrospective study

Background: Perineural local anaesthetic and steroid injections around ilioinguinal (II), iliohypogastric (IH), and genitofemoral (GF) nerves are often performed to treat chronic refractory neuropathic pain in the lower abdomen and groin, but there is a lack of published data on outcomes of these interventions. Aims: The objective of this retrospective study was to evaluate analgesic outcomes of ultrasound-guided II, IH, and GF nerve blocks in patients with chronic neuropathic pain in the lower abdominal wall and groin. Methods: Analgesic outcomes were assessed at 6 weeks after injections and patients were classified as "responders" if the numerical rating scale for pain score reduced by 30% or more. Variables analyzed for impact on outcomes included demographics, intensity of pain and duration, etiology, dose of opioid, presence of anxiety, depression, and diabetes mellitus. Results: In this cohort of 54 patients with severe baseline pain who had failed to receive analgesic benefit from recommended first- and second-line medications for neuropathic pain, 30 patients had history of surgery and 24 had pain secondary to visceral inflammatory pathologies. Twenty-five (46.3%) patients were identified as responders. A majority of the patients in this cohort had pain for more than one year. There was a higher incidence of diabetes mellitus in nonresponders compared to responders but the difference was not significant (14% and 0%, respectively; P = 0.115). Conclusions: Ultrasound-guided perineural steroids can ameliorate chronic refractory abdominal wall and groin neuropathic pain in patients who have failed to respond to conventional medical management at 6 weeks after the procedures.

State of education regarding ultrasound-guided interventions during pain fellowships in Korea: a survey of recent fellows

Background

Recently, the use of ultrasound (US) techniques in regional anesthesia and pain medicine has increased significantly. However, the current extent of training in the use of US-guided pain management procedures in Korea remains unknown. The purpose of the present study was to assess the current state of US training provided during Korean Pain Society (KPS) pain fellowship programs through the comparative analysis between training hospitals.

Methods

We conducted an anonymous survey of 51 pain physicians who had completed KPS fellowships in 2017. Items pertained to current US practices and education, as well as the types of techniques and amount of experience with US-guided pain management procedures. Responses were compared based on the tier of the training hospital.

Results

Among the 51 respondents, 14 received training at first- and second-tier hospitals (Group A), while 37 received training at third-tier hospitals (Group B). The mean total duration of pain training during the 1-year fellowship was 7.4 months in Group A and 8.4 months in Group B. Our analysis revealed that 36% and 40% of respondents in Groups A and B received dedicated US training, respectively. Most respondents underwent US training in patient-care settings under the supervision of attending physicians. Cervical root, stellate ganglion, piriformis, and lumbar plexus blocks were more commonly performed by Group B than by Group A (P < 0.05).

Conclusions

Instruction regarding US-guided pain management interventions varied among fellowship training hospitals, highlighting the need for the development of educational standards that mandate a minimum number of US-guided nerve blocks or injections during fellowships in interventional pain management.

Effects of line fiducial parameters and beamforming on ultrasound calibration

Ultrasound (US)-guided interventions are often enhanced via integration with an augmented reality environment, a necessary component of which is US calibration. Calibration requires the segmentation of fiducials, i.e., a phantom, in US images. Fiducial localization error (FLE) can decrease US calibration accuracy, which fundamentally affects the total accuracy of the interventional guidance system. Here, we investigate the effects of US image reconstruction techniques as well as phantom material and geometry on US calibration. It was shown that the FLE was reduced by 29% with synthetic transmit aperture imaging compared with conventional B-mode imaging in a Z-bar calibration, resulting in a 10% reduction of calibration error. In addition, an evaluation of a variety of calibration phantoms with different geometrical and material properties was performed. The phantoms included braided wire, plastic straws, and polyvinyl alcohol cryogel tubes with different diameters. It was shown that these properties have a significant effect on calibration error, which is a variable based on US beamforming techniques. These results would have important implications for calibration procedures and their feasibility in the context of image-guided procedures.

Ultrasound-guided interventional procedures for chronic pain management

Ultrasonography has multiple advantages over traditional radiologic imaging modalities when used for interventional procedures. It allows improved visualization of the anatomy while avoiding ionizing radiation and risks associated with contrast use. It has proved superiority at accuracy of delivery and procedural effectiveness over blind procedures when used in association with interventional pain procedures. Although limited in its ability to see through bony structures, ultrasound has utility in visualizing soft tissues and vascular structures in anatomic regions of interest resulting in increased use for posterior neuraxial, periaxial, peripheral nerve and joint-related structures. Current evidence for use in these settings is presented here. In some cases, optimal utility may be improved by combining ultrasonography with other imaging modalities.

Comparison of anatomic landmarks and ultrasound guidance for intercostal nerve injections in cadavers

BACKGROUND AND OBJECTIVES

Intercostal nerve (ICN) injections are routinely performed under anatomic landmark or fluoroscopic guidance for acute and chronic pain indications. Ultrasound (US) is being used increasingly to perform ICN injections, but there is lack of evidence to support categorically the benefits of US over conventional techniques. We compared guidance with US versus anatomic landmarks for accuracy and safety of ICN injections in cadavers in a 2-phase study that included evaluation of deposition of injected dye by dissection and spread of contrast on fluoroscopy.

METHODS

A cadaver experiment was performed to validate US as an imaging modality for ICN blocks. In the first phase of the study, 12 ICN injections with 2 different volumes of dye were performed in 1 cadaver using anatomic landmarks on one side and US-guidance on the other (6 injections on each side). The cadaver was then dissected to evaluate spread of the dye. The second phase of the study consisted of 74 ICN injections (37 US-guided and 37 using anatomic landmarks) of contrast dye in 6 non-embalmed cadavers followed by fluoroscopy to evaluate spread of the contrast dye.

RESULTS

In the first phase of the study, the intercostal space was identified with US at all levels. Injection of 2 mL of dye was sufficient to ensure compete staining of the ICN for 5 of 6 US-guided injections but anatomic landmark guidance resulted in correct injection at only 2 of 6 intercostal spaces. No intravascular injection was found on dissection with either of the guidance techniques. In the second phase of the study, US-guidance was associated with a higher rate of intercostal spread of 1 mL of contrast dye on fluoroscopy compared with anatomic landmarks guidance (97% vs 70%; P = 0.017).

CONCLUSIONS

Ultrasound confers higher accuracy and allows use of lower volumes of injectate compared with anatomic landmarks as a guidance method for ICN injections in cadavers. Ultrasound may be a viable alternative to anatomic landmarks as a guidance method for ICN injections.