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Biomedical subjects

P Mulier

Publications and source records attributed to P Mulier.

6 recordsLinked to original sources

Complications of radiofrequency coagulation of liver tumours.

BACKGROUND: Radiofrequency coagulation (RFC) is being promoted as a novel technique with a low morbidity rate in the treatment of liver tumours. The purpose of this study was to assess critically the complication rates of RFC in centres with both large and limited initial experience, and to establish causes and possible means of prevention and treatment. METHODS: This is an exhaustive review of the world literature (articles and abstracts) up to 31 December 2001; 82 independent reports of RFC of liver tumours were analysed. RESULTS: In total, 3670 patients were treated with percutaneous, laparoscopic or open RFC. The mortality rate was 0.5 per cent. Complications occurred in 8.9 per cent: abdominal bleeding in 1.6 per cent, abdominal infection in 1.1 per cent, biliary tract damage in 1.0 per cent, liver failure in 0.8 per cent, pulmonary complications in 0.8 per cent, dispersive pad skin burn in 0.6 per cent, hepatic vascular damage in 0.6 per cent, visceral damage in 0.5 per cent, cardiac complications in 0.4 per cent, myoglobinaemia or myoglobinuria in 0.2 per cent, renal failure in 0.1 per cent, tumour seeding in 0.2 per cent, coagulopathy in 0.2 per cent, and hormonal complications in 0.1 per cent. The complication rate was 7.2, 9.5, 9.9 and 31.8 per cent after a percutaneous, laparoscopic, simple open and combined open approach respectively. The mortality rate was 0.5, 0, 0 and 4.5 per cent respectively. CONCLUSION: The morbidity and mortality of RFC, while low, is higher than previously assumed. With adequate knowledge, many complications are preventable.

Carcinoma, Hepatocellular↗

Ex vivo experiment on radiofrequency liver ablation with saline infusion through a screw-tip cannulated electrode.

PURPOSE: To investigate whether radiofrequency (RF) therapy with hypertonic saline infusion through a hollow screw-tip electrode can cause a lesion size suitable for liver tumor ablation. MATERIALS AND METHODS: RF tissue ablation of 180 sites was performed by using a hollow screw-tip electrode in 40 freshly excised swine livers. Under both power and temperature control modes, the ablation effects with and without various regimes of 5% hypertonic saline (1 ml/min) prior to and/or during the procedure were compared by measuring the size of lesions at dissection and confirmed by T1 and T2 weighted magnetic resonance (MR) imaging. RESULTS: The maximal lesion diameter of 5.5 cm was reached at 30 W with saline infusion 1 min prior to and during 12 min of ablation. The smaller sizes (P < 0.01) between 0.3 and 2.5 cm in diameter were met with noninfusion or preinfusion-only groups. The RF ablation lesions appeared as hyper- and hypointense areas on T1 and T2 MR images, respectively. CONCLUSIONS: RF ablation in combination with present hollow screw-tip electrode and saline infusion allows for necrotic development of suitable size for liver tumor ablation. Such ablated lesions can be visualized with MR imaging.

Animals↗

Enhanced radiofrequency ablation of canine prostate utilizing a liquid conductor: the virtual electrode.

Conventional radiofrequency (RF) ablative techniques have shown promise for the treatment of symptomatic benign prostatic hyperplasia (BPH); however, present RF technology is limited by the small lesion size, necessitating several probe placements and heating cycles to achieve sizable lesions. This limitation is attributable primarily to a rapid increase in electrical impedance secondary to tissue desiccation and charring at the electrode tip. We devised a hollow screw-tip needle electrode that permits fixation to tissue, recording of temperature and impedance, infusion of fluid, and delivery of RF energy. Infusion of electrolyte solution (i.e., saline) into tissue prevents impedance rise by conducting RF energy away from the metal electrode and permits the creation of large lesions. By varying the conductivity of the perfusate (concentration and temperature), lesions of large diameter can be created in a controlled manner. To determine the long-term tissue effects, we applied this new modified RF technique to the prostates of five mongrel dogs in a chronic (0.5 to 8-week) study. The screw-tip electrode was serially embedded into each lobe of the perineally exposed glands with 1-minute infusion of 0.9% saline (2 mL/min) followed by application of RF energy (500 KHz, 50 W, 2-18 minutes) along with continuous saline infusion. Thermocouples were embedded 5 mm below and at the gland capsule, and RF application was discontinued when the temperature reached 50 degrees C at the periphery. Postoperatively, the animals were examined daily for clinical status and weekly for glandular changes using transrectal ultrasonography. At predetermined intervals, the animals were sacrificed and the prostates excised, measured, sectioned, and examined for histologic changes. Ablative tissue temperatures of 50 to 100 degrees C were produced while impedance remained stable. Four animals required a single catheterization for relief of urinary retention between days 2 and 3; otherwise, all animals demonstrated a quick and uneventful recovery with no edema detectable on day 7 ultrasound examination. The outside dimensions of the gland remained relatively constant throughout the study (+ or - 0.39 cm L + W + H). Histologic examination revealed coagulation necrosis (ablation) in both lobes of all prostates (69.94% + or - 16.62% of the gland) with tissueless cavities forming from the ablation area (28.71% + or - 8.24% of the gland) contained within the capsule surrounded by healthy tissue at the periphery. Intraprostatic lesions were obtained without any gross damage to surrounding tissue, including the bladder and rectal wall. Utilizing a liquid conductor in prostate tissue allows a single electrode-placement heating cycle for controlled ablation for the potential treatment of BPH. This new technique produces more extensive and uniform lesions than conventional RF procedures, and lesion size is limited only by the duration of RF energy application.

Animals↗

Primary pure squamous cell carcinoma of the antrum of the stomach: a case report.

A case of a patient with a pure squamous cell carcinoma of the stomach is presented. Surgery, the treatment of choice for this rare gastroenterological tumour, gives no guarantee for cure. Prognosis, as is demonstrated by our case, is poor with few exceptions. Different theories of histopathogenesis are discussed in the literature but no definitive statement can be made.

Abdominal Muscles↗