Comparison of high-frequency and ultrahigh-frequency probes in chronic inflammatory demyelinating polyneuropathy.

OBJECTIVES: High-frequency ultrasound (HFUS 18-20 MHz) performed on patients with chronic inflammatory demyelinating polyneuropathy (CIDP) shows a focal enlargement, particularly in the proximal segments of upper-arm motor nerves. Ultrahigh frequency ultrasound (UHFUS 30-70 MHz), having a higher spatial resolution, enables a better characterization of nerve structures. The aim of this study was to compare the two ultrasound probes in the evaluation of motor nerve characteristics in CIDP patients. METHODS: Eleven patients with definite or probable CIDP underwent an ultrasound evaluation of median and ulnar nerves, bilaterally. Nerve and fascicle cross-sectional area (CSA), vascularization, and echogenicity were assessed. RESULTS: Nerve and fascicle CSA were increased in the proximal segments, especially in the median nerve, in 9/11 patients and in 10/11 patients at the HFUS and UHFUS evaluations, respectively. A statistically significant difference between CSA values obtained with the two probes was found only for fascicle values. UHFUS allowed for a more precise estimation of fascicle size and number than the HFUS. We were able to identify nerve vascularization in 4/11 patients at UHFUS only. CONCLUSION: UHFUS gives more detailed information on the changes in the internal nerve structure in CIDP patients. In particular, it permits to better characterize fascicle size and morphology, and to have a precise estimation of their number. Its frequency range also allows to evaluate nerve vascularization. SIGNIFICANCE: Ultrasound evaluation could become an adjunctive diagnostic tool for CIDP. Further studies are needed to validate the examined parameters as biomarkers for the evaluation and follow-up of CIDP patients.

A novel radiofrequency thermocoagulation method for treatment of lower back pain: thermal conduction after instillation of saline solution into the nucleus pulposus--preliminary results.

BACKGROUND: Radiofrequency heating of the intervertebral disc has been proposed for the treatment of chronic low back pain using two methods: a flexible needle inserted into the annulus fibrosus achieving a full 360 degrees penetration, or a rigid needle inserted into the nucleus pulposus. The first technique is effective on pain, but the clinical benefit of the second is uncertain. PURPOSE: To evaluate a technique for radiofrequency heating of the lumbar intervertebral disc by a needle placed into the nucleus pulposus. MATERIAL AND METHODS: The method was tested in 17 patients according to the criteria used in previous intradiscal radiofrequency studies. Before and after treatment, disability was assessed by the Oswestry disability score. A pain reduction of at least 50% was considered a success. RESULTS: Fifteen patients were responders at 1 month (88%), nine at 3 months (53%), and 12 at 6 months (70.6%). No complications were observed. CONCLUSION: A new method of providing discal radiofrequency treatment for lower back pain had a substantial clinical benefit in 71% of the observed patients. A prospective study comparing this new method with placebo should be conducted to confirm these initial results.