Containment-enhanced Ho:YAG photofragmentation of soft tissues

William A. Christens-Barry, Michael Guarnieri, Benjamin S. Carson

Research output: Contribution to journalConference articlepeer-review


Laser surgery of soft tissue can exploit the power of brief, intense pulses of light to cause localized disruption of tissue with minimal effect upon surrounding tissue. In particular, studies of Ho:YAG laser surgery have shown that the effects of cavitation upon tissues and bone depend upon the physical composition of structures in the vicinity of the surgical site. For photofragmentation of occluding structures within catheters and other implant devices, it is possible to exploit the particular geometry of the catheter to amplify the effects of photofragmentation beyond those seen in bulk tissue. A Ho:YAG laser was used to photofragment occlusive material (tissue and tissue analogs) contained in glass capillary tubing and catheter tubing of the kind used in ventricular shunt implants for the management of hydrocephalus. Occluded catheters obtained from patient explants were also employed. Selection of operational parameters used in photoablation and photofragmentation of soft tissue must consider the physical composition and geometry of the treatment site. In the present case, containment of the soft tissue within relatively inelastic catheters dramatically alters the extent of photofragmentation relative to bulk (unconstrained) material. Our results indicate that the disruptive effect of cavitation bubbles is increased in catheters, due to the rapid displacement of material by cavitation bubbles comparable in size to the inner diameter of the catheter. The cylindrical geometry of the catheter lumen may additionally influence the propagation of acoustic shock waves that result from the collapse of the condensing cavitation bubbles.

Original languageEnglish (US)
Pages (from-to)189-196
Number of pages8
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Dec 1 1997
EventProceedings of Lasers-Tissue Interaction, Tissue Optics and Laser Welding III - San Remo, Italy
Duration: Sep 5 1997Sep 8 1997


  • Hydrocephalus
  • Laser surgery
  • Neurosurgery
  • Photoablation
  • Ventricular shunt

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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