Ultrasound-Guided Interventional Procedures in Pain Medicine: A Review of Anatomy, Sonoanatomy, and Procedures. Part IV

Visualizing Anatomic Variants of the Sciatic Nerve Using Diagnostic Ultrasound During Piriformis Muscle Injection: An Example of 4 Cases

Objective

The aim of this article is to present examples of patients in whom piriformis muscle (PM) and sciatic nerve (SN) variations were detected by a diagnostic ultrasound (US)-guided examination and were successfully diagnosed and treated for piriformis syndrome (PS) by US-guided injections.

Clinical Features

This series includes 4 cases. In case 1, a 30-year-old woman with a 7 numeric rating scale (NRS) score for pain (on a 0-10 scale) was evaluated for complaints of left gluteal pain radiating to the thigh for 5 years and right gluteal pain for 2 years. Case 2 involves a 32-year-old man with a 7 NRS score presenting with left gluteal pain radiating to his leg for 1 year. The third case presents a 37-year-old man who had pain (6 NRS score), numbness, and discomfort radiating from the right hip to the leg that lasted for 7 years. Finally, in case 4, a 23-year-old male patient was examined with deep gluteal paresthesia and discomfort on the left side for 1 year.

Intervention and Outcome

Diagnostic US evaluation of the gluteal region for each patient revealed anatomical variations of the SN. In 3 of the cases, corresponding contralateral US images demonstrated similar anatomic variations. Diagnosis of PS in each patient was made by US-guided injection. After the injection of 4 cm³ of lidocaine 2% into the PM, the patients' complaints resolved almost fully.

Conclusion

The anatomical variations of the SN and PM might be a facilitating factor for myofascial pain syndrome in PS. These cases demonstrate that SN variations could be visualized with the help of diagnostic US.

Image guidance used for large joint and bursa injections; a survey study

Objectives: To determine the current rates of use of available image guidance modalities for large joint and bursal injections, in addition to their relationships to physician demographics.Methods: An electronic survey was sent to 3,400 members of the American Medical Society for Sports Medicine (AMSSM), examining types of guidance used for each large joint and bursal injection.Results: A total of 674 sports medicine physicians responded to the survey. Intra-articular hip and glenohumeral joint injections were more commonly performed with ultrasound guidance, while palpation-guidance was more common with all other injections. Physicians who specialized in Physical Medicine & Rehabilitation (PM&R) were more likely to use ultrasound for trochanteric bursa (p = 0.007, OR = 4.16 [1.46-11.8]), while internal medicine-, pediatrics-, and family medicine-trained physicians were more likely to use palpation guidance for at least one joint (p < 0.05). Physicians with fewer years of experience were more likely to use ultrasound for glenohumeral joint injections (p ≤ 0.002 for all age groups with less than 20 years of experience, ORs ranging from 6.3 to 9.2).Conclusion: Palpation-guidance is the most common technique used for large joint and bursal injections, other than for glenohumeral and hip joint injections. PM&R-trained physicians and those with less experience tend to use ultrasound more frequently.

Ultrasound-Guided Biopsies: Medium and Large Joints

Ultrasound-guided needle synovial biopsies are useful for clinical practice and research in rheumatology. With the emergence of personalized medicine for the treatment of inflammatory rheumatic diseases, it is predicted that this technique will be increasingly used in the near future. Standardized characterization of the technical aspects of ultrasound-guided needle synovial biopsies is needed in order to produce solid evidence on the safety and effectiveness of the technique.

Ultrasound-Guided Hip Injections

The diagnosis of hip pain can be difficult to isolate because the discomfort can originate from several locations and compensatory pain patterns. Pain generators can include the intra- and extra-articular hip structures, the lumbar spine, the pelvic floor, or a combination of these. It can also be referred as pain from the bowel, bladder, or reproductive organs. Injections into and around the hip have become an important part of both diagnostic and nonsurgical treatment algorithm for hip pain. The proximity of the hip to important neurovascular structures, lack of palpable anatomic landmarks, and deep location of targets can make use of ultrasonography-guided injections ideal. These injections have been growing in popularity in the orthopedic community because ultrasonography allows for a real-time visualization of dynamic anatomy without any radiation exposure to the patient and physician. The use of ultrasonography has allowed for in-office image guidance with improved accuracy for more targeted and advanced procedures. The patient's response to these injections can help guide patient selection for surgery and allow for better pain control of the soft-tissue pathology that often accompanies intra-articular pathology. This article highlights the diagnostic and therapeutic value of ultrasonography-guided hip injections for an orthopedic practice. The focus is on sonographic anatomy, introduction to technique, common indications, and pearls and pitfalls of these procedures.

Fascia-iliaca compartment block vs intra-articular hip injection for preoperative pain management in intracapsular hip fractures: A blind, randomized, controlled trial

BACKGROUND

The aim of this study was to compare the fascia-iliaca compartment block and the intra-articular hip injection in terms of pain management and the need for additional systemic analgesia in the preoperative phase of intracapsular hip fractures.

METHODS

Patients >65 years old with an intracapsular hip fracture were randomized in this prospective, blind, controlled, parallel trial in a Level-I trauma center. Patients were randomly assigned to receive either the fascia-iliaca compartment block (cohort FICB) or the intra-articular hip injection (cohort IAHI) upon admission to the emergency department. The primary outcome was pain relief at 20 min, 12 h, 24 h and 48 h after the regional anesthesia, both at rest and during internal rotation of the fractured limb. The Numeric Rating Scale was used. Residual pain was managed with the same protocol in all patients. Additional analgesic drug administration during the 48 h from admission was recorded.

RESULTS

A total of 120 patients with comparable baseline characteristics were analyzed in this study: the FICB group consisted of 70 subjects, while the IAHI group consisted of 50 subjects. Pain was significantly lower in the IAHI group during movement of the fractured limb at 20 min (p < 0.05), 12 h (p < 0.05), 24 h (p < 0.05) and 48 h (p < 0.05). In the FICB cohort 72.9% of patients needed to take oxycodone, in contrast to 28.6% of the IAHI cohort (p < 0.05). In the FICB cohort 14.09 ± 11.57 mg of oxycodone was administered, while in the IAHI cohort 4.38 ± 7.63 mg (p < 0.05). No adverse events related to either technique were recorded.

CONCLUSIONS

Intra-articular hip injection provides better pre-operatory pain management in elder patients with intracapsular hip fractures compared to the fascia-iliaca compartment block. It also reduced the need for supplementary systemic analgesia.

LEVEL OF EVIDENCE

Therapeutic Level I.

Image-Guided High Intensity Focused Ultrasound System for Large Animal Nerve Ablation Studies

High intensity focused ultrasound (HIFU) is a form of thermal ablation technique, which can treat a variety of medical afflictions. One promising therapeutic use is the permanent destruction of nerves non-invasively in patients with severe spasticity or certain types of pain (e.g., phantom limb pain). To this end, HIFU requires ultrasound guidance, which allows the non-invasive, target-specific deposition of thermal energy to the targeted nerve, thereby blocking axonal conduction. In this paper, a composite system comprising both ultrasound-imaging and HIFU therapy was developed and used to induce localized non-invasive nerve blockage in an in vivo large animal study. Five pigs were used with the femoral nerve as the target. Calibrated needle thermocouples inserted at the target site were employed to monitor the target tissue temperature. The degree of nerve blockage was assessed by measuring compound action potential (CAP) signal with a clinical nerve electrophysiology system before and after HIFU exposures. An average CAP signal amplitude reduction of 49% of baseline with a standard deviation of 9% was observed after 20–30 min post exposure. These results demonstrate the feasibility of the proposed ultrasound-guided HIFU modality as a potential non-invasive nerve ablation method.

Ultrasound-Guided Hip Procedures

This article describes the techniques for performing ultrasound-guided procedures in the hip region, including intra-articular hip injection, iliopsoas bursa injection, greater trochanter bursa injection, ischial bursa injection, and piriformis muscle injection. The common indications, pitfalls, accuracy, and efficacy of these procedures are also addressed.

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.