A model to study thermal energy delivery to the choroid: A comparison of surgical devices

Stephen A. Lobue, Prashant Tailor, Jarel K. Gandhi, Paul Loftness, Timothy Olsen

Research output: Contribution to journalArticle

Abstract

Purpose: We measure and compare surgical devices using an ex vivo, temperature-controlled, choroidal incision model during thermal energy transfer with a high-resolution infrared camera. Methods: Ex vivo porcine choroidal tissue specimens (n = 516) were isolated and placed on a temperature-regulated (37∘C) perfusion platform. We tested the pulsed electron avalanche knife (PEAK), micropulse laser (MpL), continuous laser (CL), and bipolar cautery (BpC) at three energy settings (11 [low], 45 [medium], and 134 [high] mJ/mm). Each device was clamped to a stationary mechanical arm. Movement of tissue specimens beneath the surgical device was achieved using a stepping motor-driven x-y table. An infrared video camera measured orthogonal temperature variation in the surrounding tissue. Results: Increased power resulted in greater lateral thermal spread using all modalities (P < 0.001). Mean (standard deviation) lateral thermal spread at low energy was smallest for the MpL at 0.0 (0.01) mm (P < 0.001), whereas BpC had the least collateral tissue damage at medium and high energies (0.02 [0.08] and 0.34 [0.22] mm, respectively; P < 0.001). Fluidics of the ex vivo system may limit thermal spread. The PEAK had the greatest thermal spread across all energy groups (P < 0.001), with clinically relevant variation between disposable blades. Conclusions: Our ex vivo model enabled direct comparison of threshold thermal tissue injury across four devices. MpL and BpC showed the least thermal damage. PEAK had a higher variation in energy delivery, but also has the advantage of more effective tissue cutting. Translational Relevance: Our ex vivo surgical device analysis provides thermal tissue injury predictions for choroidal surgery.

Original languageEnglish (US)
Article number39
JournalTranslational Vision Science and Technology
Volume7
Issue number6
DOIs
StatePublished - Nov 1 2018

Fingerprint

Choroid
Thermal energy
Hot Temperature
Tissue
Equipment and Supplies
Avalanches
Cautery
Lasers
Electrons
Temperature
Infrared radiation
Stepping motors
Fluidics
Video cameras
Energy Transfer
Wounds and Injuries
Laser Therapy
Energy transfer
Surgery
Thermoanalysis

Keywords

  • Choroid
  • Lateral thermal spread
  • Micropulse laser
  • PEAK
  • Retinal pigment epithelium

ASJC Scopus subject areas

  • Biomedical Engineering
  • Ophthalmology

Cite this

A model to study thermal energy delivery to the choroid : A comparison of surgical devices. / Lobue, Stephen A.; Tailor, Prashant; Gandhi, Jarel K.; Loftness, Paul; Olsen, Timothy.

In: Translational Vision Science and Technology, Vol. 7, No. 6, 39, 01.11.2018.

Research output: Contribution to journalArticle

Lobue, Stephen A. ; Tailor, Prashant ; Gandhi, Jarel K. ; Loftness, Paul ; Olsen, Timothy. / A model to study thermal energy delivery to the choroid : A comparison of surgical devices. In: Translational Vision Science and Technology. 2018 ; Vol. 7, No. 6.
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