Pharmacology of spinal interventions: review of agents used in spine pain procedures

Spine procedures are commonly performed to diagnose and treat various spinal conditions, ranging from degenerative disc disease to vertebral fractures. These procedures often involve the use of pharmaceutical agents to enhance the efficacy of the intervention and improve patient outcomes. This review provides an overview of the pharmaceuticals commonly utilized in spine procedures, including corticosteroids, anesthetics, antibiotics, radiographic contrast, neurolytic agents, and materials used in kyphoplasty and vertebroplasty. This review summarizes the utilization of these pharmaceutical agents in spine procedures in an effort to optimize patient outcomes. Understanding the pharmacological properties and appropriate uses of these pharmaceuticals is essential for interventionalist and healthcare providers involved in the care of patients undergoing spinal interventions.

A case of celiac plexus block causing iatrogenic Cushing's syndrome

Treatment with corticosteroids can lead to iatrogenic Cushing's syndrome when used for longer intervals and in high doses. Less common administration routes may conceal the exposure, raising the possibility of misdiagnosis and mismanagement.

Tips and tricks in ultrasound-guided musculoskeletal interventional procedures

Ultrasound visualization affords proceduralists versatile and accurate guidance for a variety of percutaneous, minimally invasive procedures in the musculoskeletal system including joint (intra-articular) injections or aspirations, intra-bursal injections, peritendinous, and perineural injections. A variety of percutaneous procedures are traditionally performed blindly, but may be more easily or more accurately performed with the real-time assistance of ultrasound guidance. Other procedures are only possible utilizing image-guidance, due to the required precision of the injection because of delicate local anatomy or depth of the injection; ultrasound is a safe, portable, and widespread modality that can be used to assist the proceduralist in localizing the needle tip in such cases, to ensure safe and accurate delivery of the medication, most frequently a solution of steroid and anesthetic. This review aims to provide a foundational approach to ultrasound-guided procedures in the musculoskeletal system, offering tips and tricks that can be employed in many different procedures including intra-articular, juxta-articular, and perineural injections for a multitude of clinical scenarios. Technical considerations regarding ultrasound transducer selection, sonographic technique, as well as common indications, contraindications, and complications of these procedures, are presented. Additionally, a variety of pharmacologic considerations for proceduralists contemplating ultrasound-guided injections are discussed.

Precision pain management in interventional radiology

Pain is a common manifestation of several benign and malignant conditions. Inadequate response to conservative therapies is often succeeded by incremental use of analgesics and opioids; however, such an approach is often ineffective, not well tolerated by patients, and carries the risk of addiction leading to the opioid crisis. Implementing minimally invasive percutaneous procedures, performed by interventional radiologists has proven to be successful in providing safe, effective, and patient-specific therapies across a wide range of painful conditions. In the present narrative review, we will review the repertoire of minimally invasive imaging guided interventions, which have been successfully used to treat common painful benign and malignant conditions. We briefly describe each technique, common indications, and expected results.

Selective Nerve Root Block in Treatment of Lumbar Radiculopathy: A Narrative Review

Selective Nerve Root Block (SNRB) is a precise local injection technique that can be utilised to target a particular inflamed nerve root causing lumbar radiculopathy for both diagnostic and therapeutic purposes. Usually, for SNRB to be therapeutic, a combination of a local anaesthetic agent and a steroid is injected under imaging guidance, whereas for diagnostic purposes, just the local anaesthetic agent is injected. While the ideal treatment strategy is to relieve the nerve root from its compressing pathology, local injection of steroids targeted at the affected nerve root can also be attempted to reduce inflammation and thus achieve pain relief. Although the general principle for administering an SNRB remains largely the same across the field, there are differences in techniques depending on the region and level of the spine that is targeted. Moreover, drug combinations utilised by clinicians vary based on preference. The proven benefits of SNRBs largely outweigh their risks, and the procedure is deemed safe and well tolerated in a majority of patients. In this narrative, we explore the existing literature and seek to provide a comprehensive understanding of SNRB as a treatment for lumbar radiculopathy, its indications, techniques, outcomes, and complications.

Posttraumatic cicatricial sciatic nerve entrapment: dynamic imaging and percutaneous neurolysis

We describe a case of late-onset sciatic neuralgia due to cicatricial tethering of the sciatic nerve by a retracted torn hamstring muscle that was successfully treated with percutaneous neurolysis. Ultrasound and MRI showed a chronic complete avulsion of the proximal hamstring complex with fatty atrophy of the retracted hamstring muscles. Dynamic ultrasound and magnetic resonance imaging displayed tethering of the retracted hamstring complex to the sciatic nerve caused by cicatricial adhesions. Whereas hamstring injuries are highly prevalent sports injuries, there are only a small number of reported cases in the literature of late-onset sciatic nerve involvement. We highlight the benefits of dynamic ultrasound and magnetic resonance imaging and propose ultrasound-guided percutaneous neurolysis as a viable minimally invasive treatment option.

Encephalopathy after unintentional intrathecal gadolinium: A letter to the editor

Objective

Raise awareness of gadolinium encephalopathy, a rare cause of neurological symptoms.

Setting

An L5-S1 interlaminar epidural steroid injection (IL-ESI) was performed with a gadolinium-based contrast agent (GBCA) due to the patient's history of allergic reaction to iodine-based contrast agents.

Discussion

Several hours after administration of GBCA, the patient had nausea and vomiting with altered mental status. Patient was treated with dexamethasone IV, and was discharged on day 2. Patient had no residual deficits at follow-up two weeks later. Current literature shows that caution should be used to prevent inadvertent intrathecal GBCA, and doses >2.0 mmols are associated with serious adverse effects, including death.

Conclusions

Intrathecal administration of GBCAs should be limited to less than 0.5 mmol. If adverse effects are experienced, IV steroids should be administered as soon as possible, and a CSF drain should be considered.

Assessing the impact of adding bupivacaine on immediate and delayed post-procedure pain scores in interlaminar epidural steroid injections

OBJECTIVE

A local anesthetic is frequently administered as part of a lumbar epidural steroid injection (LESI); however, there is a rare potential for this to result in transient paralysis if administered incorrectly. The purpose of this retrospective study is to determine if the addition of bupivacaine significantly improves patient-reported pain scores.

MATERIALS AND METHODS

This retrospective review includes patients undergoing LESI over an approximately 1 year time span. Pre-procedure, immediate post-procedure, and 1-week integer scaled pain scores were recorded. Ordinal regression was used to compare the distributions of the aggregated ordinal pain score categories between bupivacaine- and non-bupivacaine-injected patients.

RESULTS

Two hundred fifty-eight patients met the inclusion criteria (126F:132 M, mean age 64.7 years) with 164 receiving bupivacaine and steroids and 94 receiving steroids alone. The relative frequency distributions for pre-injection pain did not differ between the bupivacaine patients and the non-bupivacaine patients (p = 0.114). Similarly, the relative frequency distributions for immediate and 1-week post-procedure pain did not differ between the bupivacaine patients and the non-bupivacaine patients (p = 0.293 at immediate time point and p = 0.306 at 1-week time point). Odds ratios comparing pain severity change between the bupivacaine and non-bupivacaine patients also were not significantly different at either the immediate post-procedure (p = 0.769) or 1-week (p = 0.203) time points.

CONCLUSION

The lack of a significant downward shift in the bupivacaine patients' post-procedure pain scores compared to the non-bupivacaine patients' post-procedure pain scores raises doubts about bupivacaine's utility as a standard component of a lumbar epidural injection.

Observer agreement in the choice of lumbar spine injection for pain management

BACKGROUND AND PURPOSE

Lumbar spine MRI can help guide the choice of corticosteroid injection in pain management. We investigated whether patient-reported symptom information from a questionnaire could improve agreement in the choice of type, level, and side of injection.

MATERIALS AND METHODS

In this prospective observational study, 120 patients (median age 64, 70 men) were recruited from patients referred for pain management. After informed consent, they completed electronic questionnaires that obtained symptom information for later use during MRI reviews. In 3 research arms, 6 radiologists chose injections that would ideally deliver corticosteroid to the presumed sources of pain in (1) MRI studies reviewed with symptom information from questionnaires, (2) MRI studies reviewed without symptom information, and (3) MRI reports. Blinded to questionnaire results, radiologists providing clinical care and interviewing patients chose ideal therapeutic injections to establish reference standards. Injections were categorized by type, level, and side and compared using percent agreement and kappa statistics. Interreading agreement was analyzed.

RESULTS

Compared to the reference standard, kappa agreements for injection types, levels, and sides were almost perfect when MRIs were reviewed knowing symptoms (0.85-0.93), fair without symptoms (0.23-0.35) (all P < .001) and fair in MRI reports (0.24-0.36) (all P < .001). Interreading kappa agreements were almost perfect knowing symptoms (0.82-0.90), but only moderate without symptoms (0.42-0.49) (all P < .001).

CONCLUSIONS

Radiologists reviewing lumbar spine MRI converged on the type, level, and side of ideal therapeutic injection whether they obtained symptom information from direct patient interview or electronic questionnaire. Observer agreement was significantly lower without symptom information.

Image-guided spinal injection for pain management

Radiculopathy and spinal pain are debilitating conditions affecting millions of people worldwide each year. While most cases can be managed conservatively with physiotherapy and nonsteroidal anti-inflammatory medications, minimally invasive corticosteroid injections are the mainstay intervention for those not responsive to conservative treatment. Historically, spinal injections were performed in the absence of imaging guidance; however, imaging modalities, in particular fluoroscopy and computer tomography (CT), have become the standard of care in performing most of these procedures. Under imaging guidance, operators can accurately confirm needle placement and safely target localised pathologies.

Randomized controlled trials between dorsal root ganglion thermal radiofrequency, pulsed radiofrequency and steroids for the management of intractable metastatic back pain in thoracic vertebral body

BACKGROUND

Bone metastasis is a complication of various cancers causing severe pain. The current modalities for the treatment of metastatic axial pain include pharmacological, surgical and vertebral augmentation techniques, each of which has its own challenges.

OBJECTIVES

To evaluate the effectiveness of pulsed radiofrequency (PRF), thermal radiofrequency (RF) and steroids on dorsal root ganglion (DRG) in patients with thoracic axial pain due to vertebral metastasis.

METHODS

In this randomized controlled prospective study, 140 patients were assessed for eligibility, of which only 69 fulfilled the criteria. Patients were randomly divided into three equal groups, PRF, RF and steroid.

RESULTS

During the assessment of pain using Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), Opioid consumption using oral Morphine Equivalence (OME) and Analgesic Quantification Algorithm (AQA) - at baseline, 1 week, 1 month and 3 months - 81 patients were assessed for final eligibility, of which 12 were excluded before intervention due to drop-out. The remaining 69 were randomized (mean age: 53.87 ± 10.55, 55.78 ± 7.34 and 59.39 ± 13.72) for PRF, RF and steroid, respectively with no statistical difference. VAS% and ODI% decreased significantly at 3 months in RF group (p <0.001, 0.014, respectively), as did the AQA (p <0.027). Steroid group was the worst.

DISCUSSION

RF on DRG is the main stay for controlling intractable metastatic pain. PRF is a good alternative.

[Evidence in Infiltrative Pain Therapy of the Musculoskeletal System]

Musculoskeletal pain symptoms frequently generate limitations in daily work and life in many patients. Usually, symptomatic treatment is possible before clarifying the in depth diagnosis. A symptom-based infiltration therapy will never replace a thoroughly done physical examination and thoughtful collection of patient history, however, it can be of great benefit for the patient when done focused on the point of pain and executed with profound anatomical knowledge. Furthermore, the knowledge of the level of evidence of therapeutic infiltrations improves their outcomes and shapes realistic patients' expectations. Ultrasound-guided therapeutic infiltrations improve the outcome despite the use of lower amounts of active agents by pinpointed applications. This article provides an overview of the scientific evidence of effectiveness of (ultrasound-guided) infiltration techniques in diverse musculoskeletal regions.

Complications in image-guided musculoskeletal injections

OBJECTIVE

To establish the incidence and define the nature of complications occurring following image-guided musculoskeletal injections at our institution.

MATERIALS AND METHODS

All patients undergoing image-guided musculoskeletal injection during the study period (16/3/2016 to 24/01/2020) were included. Departmental records were reviewed to identify all patients describing possible complications following injection, what therapy was required (if any) and what the outcome was. No patients were excluded. Complications were classified as minor or major. Injections were categorised as follows: cervical spine, lumbar facet joint, lumbar nerve root, caudal epidural and 'other'. The complication rate for each individual category of procedure was compared with the combined complication rate for all other categories by constructing contingency tables and using Fisher's exact test.

RESULTS

A total of 8226 patients underwent image-guided musculoskeletal injections within the study period. Exactly 100 patients were identified as having reported a complication, producing an overall complication rate of 1.2%. One complication was categorised as 'major', with the patient requiring expedited surgery. The remainder (99 patients) were categorised as having experienced minor complications. The incidence of complications after 'other' injections was significantly greater than for other categories of injection (1.86%, p = 0.028). There was no significant difference in the complication rate for cervical spine (0.93%, p = 0.257), lumbar nerve root (0.85%, p = 0.401), lumbar facet joint (0.67%, p = 0.326) or caudal epidural (1.29%, p = 0.687) injections. 'Other' injections were subsequently further sub-categorised by anatomical site and imaging modality used. Glenohumeral (2.97%, p = 0.0361) and sacro-iliac (3.51%, p = 0.0498) joint injections were associated with a significantly increased risk of complications. There was no difference in the incidence of complications with fluoroscopic or ultrasound guidance.

CONCLUSION

In conclusion, image-guided musculoskeletal injections are safe and well-tolerated procedures. Complications are rare, occurring in just 1.2% of patients. 99% of complications are minor, either not requiring intervention or resolving with simple supportive treatment.

Image-guided Sports Medicine and Musculoskeletal Tumor Interventions: A Patient-Centered Model

The spectrum of effective musculoskeletal (MSK) interventions is broadening and rapidly evolving. Increasing demands incite a perpetual need to optimize services and interventions by maximizing the diagnostic and therapeutic yield, reducing exposure to ionizing radiation, increasing cost efficiency, as well as identifying and promoting effective procedures to excel in patient satisfaction ratings and outcomes. MSK interventions for the treatment of oncological conditions, and conditions related to sports injury can be performed with different imaging modalities; however, there is usually one optimal image guidance modality for each procedure and individual patient. We describe our patient-centered workflow as a model of care that incorporates state-of-the-art imaging techniques, up-to-date evidence, and value-based practices with the intent of optimizing procedural success and outcomes at a patient-specific level. This model contrasts interventionalist- and imaging modality-centered practices, where procedures are performed based on local preference and selective availability of imaging modality or interventionalists. We discuss rationales, benefits, and limitations of fluoroscopy, ultrasound, computed tomography, and magnetic resonance imaging procedure guidance for a broad range of image-guided MSK interventions to diagnose and treat sports and tumor-related conditions.

Systemic effects of fluoroscopically guided epidural steroid injection with dexamethasone

Background

Epidural steroid injections (ESIs) have been widely used in managing spinal pain. Dexamethasone has recently emerged as a useful drug in this setting, relative to particulate steroids, although the associated systemic effects have not been fully elucidated. This study aimed to investigate the incidences and types of systemic effects after fluoroscopically guided ESI with dexamethasone.

Methods

This retrospective study included 888 ESIs with dexamethasone (fluoroscopically guided at the cervical and lumbosacral levels) performed on 825 patients during January to June 2017. Data regarding systemic effects were collected via telephone interviews using a standardized questionnaire at 2 weeks after the procedure. Data on patient demographic, clinical, and procedural characteristics were collected and analyzed to identify factors that were associated with systemic effects. All statistical analyses were performed using the chi-squared test.

Results

Among the 825 patients, 40 patients (4.8%) experienced systemic effects during the 2-week follow-up period. The most common systemic effect was facial flushing (12 patients, 1.5%), which was followed by urticaria (7 patients, 0.8%) and insomnia (7 patients, 0.8%). A history of spine surgery was significantly associated with the occurrence of systemic effects (P = 0.036). Systemic effects were significantly more common for injections at the cervical level than at the lumbar level (P = 0.019).

Conclusions

Approximately 4.8% of the patients who underwent ESI with dexamethasone experienced minor and transient systemic effects. These effects were more common in patients who had undergone a previous spine surgery or received a cervical ESI.

Trends in steroid agent and diluent choices for epidural steroid injections: a survey of Spine Intervention Society physicians

BACKGROUND

Epidural steroid injections (ESIs) are a frequently used treatment for refractory radicular spinal pain. ESIs, particularly transforaminal epidural steroid injections (TFESI), may provide pain relief and delay the need for surgery. Corticosteroid agent and diluent choices are known to impact the safety of ESIs. In particular, the risk of embolization with particulate corticosteroids has led to recommendations for non-particulate steroid use by the Multisociety Pain Workgroup. Additionally, there is in vitro evidence that ropivacaine can crystalize in the presence of dexamethasone, potentially creating a particulate-like injectate. Despite widespread use and known risk mitigation strategies, current practice trends related to steroid and diluent choices are unknown.

OBJECTIVE

Identify the use of particulate versus non-particulate corticosteroids for epidural steroid injections in the cervical and lumbar spine, as well as local anesthetics commonly used as diluents during these procedures.

METHODS

Cross-sectional survey study of 314 physician members of the Spine Interventional Society.

RESULTS

41% and 9% of providers reported using particulate corticosteroids during lumbar TFESIs and cervical TFESI, respectively. Four per cent of providers reported the use of ropivacaine in cervical TFESIs. Forty-four per cent of respondents reported using anesthetic in cervical interlaminar ESIs. 21% of providers report using high volumes (> 4.5 mL) during cervical interlaminar ESIs.

CONCLUSION

Current trends, as assessed by this survey study, indicate substantial variability in steroid and diluent choice for ESIs. Patterns were identified that may impact patient safety including the continued use of particulate corticosteroids for TFESIs and the use of ropivacaine during TFESIs by a subset of respondents.

Fluoroscopically Guided Facet Injections: Comparison of Intra-Articular and Periarticular Steroid and Anesthetic Injection on Immediate and Short-Term Pain Relief

BACKGROUND AND PURPOSE

The effectiveness of facet injections is unclear in the literature. Our objective was to determine the immediate and short-term efficacy of intra-articular and periarticular steroid/anesthetic injections for facet-mediated lumbar pain.

MATERIALS AND METHODS

All outpatient fluoroscopically guided facet injections at a single institution during a 54-month period were retrospectively and independently reviewed by 2 musculoskeletal (MSK) trained radiologists. All intra-articular, all periarticular, and partial intra-/periarticular injection locations were determined. Periarticular and partial peri-/intra-articular injections were combined for analysis. Preinjection, immediate, and 1-week postinjection numeric pain scores, patient age, sex, anesthetic/steroid mixture, fluoroscopic time, and physician performing the procedure were recorded.

RESULTS

Seventy-seven patients (mean age, 51.1 years) had 100 procedures with 205 total facet joints injected. All intra-articular, all periarticular, and partial peri-/intra-articular injections constituted 54%, 20%, and 26% of the cases, respectively. The immediate and 1-week postprocedural change in pain was -3.7 (95% CI, -4.5 to -2.8; P < .001) and -1.4 (95% CI, -2.2 to -0.6; P = .001) for the all intra-articular and -3.6 (95% CI, -4.4 to -2.9; P < .001) and -1.2 (95% CI, -1.9 to -0.4; P = .002) for the combined group. Changes in immediate pain were significantly associated with the prepain level (P < .001) and patient age (P = .024) but not with the anesthetic used. Analyses revealed no significant difference in pain reduction between the groups either immediately or 1 week postinjection. Intra-articular injections required less fluoroscopic time (geometric mean, 39 versus 52 seconds) (P = .005).

CONCLUSIONS

Intra-articular and periarticular fluoroscopically guided facet injections provide statistically significant and similar pain relief both immediately and 1 week postinjection.

Neuroprotective effects of estrogen in CNS injuries: insights from animal models

Among the estrogens that are biosynthesized in the human body, 17β-estradiol (estradiol or E2) is the most common and the best estrogen for neuroprotection in animal models of the central nervous system (CNS) injuries such as spinal cord injury (SCI), traumatic brain injury (TBI), and ischemic brain injury (IBI). These CNS injuries are not only serious health problems, but also enormous economic burden on the patients, their families, and the society at large. Studies from animal models of these CNS injuries provide insights into the multiple neuroprotective mechanisms of E2 and also suggest the possibility of translating the therapeutic efficacy of E2 in the treatment SCI, TBI, and IBI in humans in the near future. The pathophysiology of these injuries includes loss of motor function in the limbs, arms and their extremities, cognitive deficit, and many other serious consequences including life-threatening paralysis, infection, and even death. The potential application of E2 therapy to treat the CNS injuries may become a trend as the results are showing significant therapeutic benefits of E2 for neuroprotection when administered into the animal models of SCI, TBI, and IBI. This article describes the plausible mechanisms how E2 works with or without the involvement of estrogen receptors and provides an overview of the known neuroprotective effects of E2 in these three CNS injuries in different animal models. Because activation of estrogen receptors has profound implications in maintaining and also affecting normal physiology, there are notable impediments in translating E2 therapy to the clinics for neuroprotection in CNS injuries in humans. While E2 may not yet be the sole molecule for the treatment of CNS injuries due to the controversies surrounding it, the neuroprotective effects of its metabolite and derivative or combination of E2 with another therapeutic agent are showing significant impacts in animal models that can potentially shape the new treatment strategies for these CNS injuries in humans.