Ultrasound-Guided Nerve Hydrodissection for Pain Management: Rationale, Methods, Current Literature, and Theoretical Mechanisms.

Nerve hydrodissection (HD), a technique used when treating nerve entrapments, involves the injection of an anesthetic, saline, or 5% dextrose in water to separate the nerve from the surrounding tissue, fascia, or adjacent structures. Animal models suggest the potential for minimal compression to initiate and perpetuate neuropathic pain. Mechanical benefits of HD may relate to release of nervi nervorum or vasa nervorum compression. Pathologic nerves can be identified by examination or ultrasound visualization. The in-plane technique is the predominant and safest method for nerve HD. Five percent dextrose may be favored as the preferred injectate based on preliminary comparative-injectate literature, but additional research is critical. Literature-based hypotheses for a direct ameliorative effect of dextrose HD on neuropathic pain are presented.

Ultrasound-Guided Lumbar Intradiscal Injection for Discogenic Pain: Technical Innovation and Presentation of Two Cases.

We described two cases and the techniques for using the ultrasound (US) to guide lumbar intradiscal injection with platelet-rich plasma (PRP). The two cases suffered from chronic low back pain. Magnetic resonance imaging revealed posterior annular tear of the L5/S1 intervertebral disc (IVD) in the first case and L4/5 and L5/S1 IVDs in the second case. For the US-guided lumbar intradiscal injection, the patient was placed in a prone position. By placing the transducer in the axial plane at the interlaminar space, the needle was directed toward the center of the aimed IVD. The needle tip was ensured inside the IVD by using the end-feel of sudden reduction of resistance and the poking technique with the transducer oriented in the paramedian sagittal oblique plane. At the follow-up, both patients had significant improvement after the intradiscal PRP injections (visual analogue scale from 7.5 to 1.5 on average). The report indicated US-guided lumbar intradiscal PRP injection to be a feasible approach for treatments of low back pain. Familiarization of the anatomy and sonoanatomy of the lumbar spine is fundamental to achieve the success of intradiscal injection.

Use of high-resolution ultrasound to measure changes in plantar fascia thickness resulting from tissue creep in runners and walkers.

OBJECTIVE: This study sought to use high-resolution ultrasound to measure changes in plantar fascia thickness as a result of tissue creep generated by walking and running. METHODS: Independent samples of participants were obtained. Thirty-six walkers and 25 runners walked on a treadmill for 10 minutes or ran for 30 minutes, respectively. Standardized measures of the thickness of the plantar fascia were obtained in both groups using high-resolution ultrasound. RESULTS: The mean thickness of the plantar fascia was measured immediately before and after participation. The mean plantar fascia thickness was decreased by 0.06 ± 0.33 mm SD after running and 0.03 ± 0.22 mm SD after walking. The difference between groups was not significant. CONCLUSION: Although the parameters of this study did not produce significant changes in the plantar fascia thickness, a slightly higher change in the mean thickness of the plantar fascia in the running group deserves further investigation.

Sonography of the normal greater occipital nerve and obliquus capitis inferior muscle.

BACKGROUND: To use sonography to measure the cross-sectional area (CSA) of the greater occipital nerve (GON) and the adjacent obliquus capitis inferior muscle (OCI) in normal subjects. METHODS: Data from 30 asymptomatic subjects between the ages of 22 and 35 were collected. CSA and circumference of the GON and CSA of OCI were measured using sonography. Interexaminer reliability analysis was performed using the intraclass correlation coefficient. RESULTS: The CSA of the GON and OCI were 2 mm2 +/- 1 mm2 and 1.86 cm2 +/- 0.51 cm2, respectively. The average circumference of the GON was 4.8 mm +/- 1.3 mm. The interexaminer reliability of the measurements was excellent with intraclass correlation coefficient coefficients of 0.91, 0.84, and 0.73 for the GON CSA, GON circumference, and OCI CSA, respectively. CONCLUSION: We report the normal values of the CSA of the GON and OCI. Knowledge of these normal values may facilitate the diagnosis of GON entrapment and provide outcome measures in therapeutic interventions.

Normative cross-sectional area of the brachial plexus and subclavian artery using ultrasonography.

OBJECTIVE: Ultrasonography has been used to measure the cross-sectional area (CSA) of peripheral nerves, but the CSA of the brachial plexus has not previously been reported. The purpose of this study was to establish a reference range of values for the CSA of the brachial plexus, subclavian artery, and peak systolic velocity (PSV) of the subclavian artery in healthy subjects using ultrasonography. METHODS: Thirty-two asymptomatic subjects (19 men, 13 women) from a chiropractic college with an average age of 29.5 +/- 9.6 participated in the study. The brachial plexus and subclavian artery CSA were measured at 3 locations: interscalene, first rib, and infraclavicular. The PSV of the subclavian artery was measured in both supraclavicular and infraclavicular locations. Each subject was imaged bilaterally. Means and 95% confidence intervals were calculated. Interexaminer reliability was evaluated between 2 examiners on 15 randomly selected subjects. RESULTS: The average CSA for the brachial plexus at the interscalene space, first rib, and infraclavicular location was 0.75 +/- 0.05, 0.96 +/- 0.07, and 0.98 +/- 0.07 cm(2), respectively. The average CSA for the subclavian artery at the same locations was 0.35 +/- 0.03, 0.38 +/- 0.03, 0.35 +/- 0.03 cm(2), respectively. The average subclavian artery PSV in supraclavicular and infraclavicular locations was 98 +/- 8 and 93 +/- 7 cm/s, respectively. The overall interexaminer reliability was poor at 0.39 (0.20-0.55). CONCLUSIONS: This is the first study to obtain normative CSA measurements of the brachial plexus and subclavian artery in multiple locations of the thoracic outlet as well as interexaminer reliability data. These data may be beneficial in future studies designed to assess the brachial plexus and subclavian artery in patients with thoracic outlet syndrome.