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Effects of high‐intensity focused ultrasound on the intervertebral disc: A potential therapy for disc herniations
Author(s) -
Forslund Carina,
Persson Johan,
Strömqvist Bjorn,
Lidgren Lars,
McCarthy Ian D.
Publication year - 2006
Publication title -
journal of clinical ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.272
H-Index - 61
eISSN - 1097-0096
pISSN - 0091-2751
DOI - 10.1002/jcu.20242
Subject(s) - ultrasound , medicine , biomedical engineering , in vivo , intervertebral disc , intensity (physics) , high intensity focused ultrasound , intervertebral disk , degree celsius , anatomy , radiology , lumbar , optics , physics , thermodynamics , microbiology and biotechnology , biology
Purpose. To determine the potential application of high‐intensity focused ultrasound for the minimally invasive treatment of herniated intervertebral discs by developing a probe that produces sufficiently high temperature locally to shrink collagen fibers (65–75°C). Materials and Methods. A 5‐mm ultrasound probe was produced with a geometric focal length of 15 mm. The probe produced 2.5 W of acoustic power and was operated at a frequency of 4.1 MHz. Measurements of temperature increase were performed in discs from bovine tails. In vivo experiments were performed to assess histologic changes in the disc as well as in nerve root and muscle. Results. Sufficient temperature increase to produce collagen shrinkage was observed close to the focus of the ultrasound. Temperature measurements in vertebral end plates showed a temperature increase of only 4°C after 60‐second exposure of the disc. In vivo experiments revealed histologic changes in the disc consistent with collagen shrinkage, with no adverse effects seen in surrounding tissues. Conclusions. The experiments demonstrated the feasibility of high‐intensity focused ultrasound in the treatment of contained herniated discs. This technique has several advantages over other thermal treatment modalities. © 2006 Wiley Periodicals, Inc. J Clin Ultrasound 34:330–338, 2006