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 language | English (US) |
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Article number | 39 |
Journal | Translational Vision Science and Technology |
Volume | 7 |
Issue number | 6 |
DOIs | |
State | Published - Nov 2018 |
Keywords
- Choroid
- Lateral thermal spread
- Micropulse laser
- PEAK
- Retinal pigment epithelium
ASJC Scopus subject areas
- Biomedical Engineering
- Ophthalmology