Ruppert, D.D. (Delia) (2017) Heat distribution, histological changes and biomechanical properties of distal animal femurs after ablation with RFA in an ex-vivo model. thesis, Medicine.
Full text available on request.Abstract
Orthopedic oncology is the medical field where cancer of the bone is treated, which is either caused by a primary or secondary tumor. The treatment of bone cancer often involves surgery, leading to either limb amputation or limb sparing surgery. Investigating different limb sparing treatments of malignant bone tumors is a continuing concern within the field of orthopedic oncology. It involves the removal of the tumor and reconstructive surgery, with different methods being allograft, autograft, graft-prosthesis and tumor prosthesis. Unfortunately this treatment often comes with short or long term limitations such as infection, pseudarthrosis, mechanical failures and fracture, sometimes leading to the necessity of a revision surgery. To further improve functional outcome after surgery, it is of interest to find a method, which eradicates the tumor cells, but at least partially avoids the previously mentioned disadvantages. A method proposed to fulfill such expectations could be the local tumor ablation (LTA) with radiofrequency ablation (RFA), a minimally invasive procedure to have shown success and little complications, which leads to tissue necrosis by hyperthermia of approximately 60 to 80 °C. In this study we investigated the heat distribution during RFA and the histological and biomechanical changes in distal animal femurs after ablation with RF. A Pilot Project was carried out at the beginning of the research in order to familiarize with the experimental set up, ablation technique and determining ablation time. Ablation was carried out for 10-12 minutes using the Cool-Tip RFA E-series equipment with both electrode exposure tip depths of 2 cm and 3 cm. Heat distribution was measured at distances of 5 mm, 10 mm and 15 mm distance from the ablating electrode during ablation by electrical thermocouple thermometers inserted into previously drilled holes. Measurements showed temperatures >57°C at a distance of 5 mm, 40-51°C at 10 mm and a maximum of 41.7°C at 15 mm. Histological examination of the bone showed necrotic zones with a maximum diameter of 15 mm when using a 3 cm exposure tip electrode. Results from the torsion test with a rotation rate of 0.5°/sec indicated no correlation between the strength of the bone and RFA. The findings of this study correlate with previous findings regarding the heat distribution and necrotic zone. In addition, it could not be demonstrated that RFA weakens the bone at the ablated site.
| Item Type: | Thesis (Thesis) |
|---|---|
| Supervisor name: | Supervisors: and Jutte, Dr Paul C. & and Dierselhuis, Edwin and Department of Orthopedic Surgery, University Medical Center |
| Faculty: | Medical Sciences |
| Date Deposited: | 25 Jun 2020 10:48 |
| Last Modified: | 25 Jun 2020 10:48 |
| URI: | https://umcg.studenttheses.ub.rug.nl/id/eprint/888 |
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