Influence of change in surgical practice for benign thyroid disease on postsurgical outcome-Single-center experience in 1400 patients.

PURPOSE: To evaluate the rate of surgical complications during the change from subtotal resection to hemithyroidectomy or thyroidectomy over a period of 17 years. METHODS: All operations for benign goiter at our hospital were analyzed for the periods 1996-2002 (Group 1) and 2003-2012 (Group 2). The groups were compared for recurrent laryngeal nerve damage, hypocalcemia, and other surgical complications directly postoperatively. RESULTS: In total, 1462 patients were operated on for goiter between 1996 and 2012. There were 1219 patients who underwent a primary thyroid operation, whereas 50 patients had surgery for recurrence. Postoperative histology revealed thyroid cancer in 193 patients (13.2%). In Group 1, 42.7% of all operated lobes were performed as lobectomies and 57.3% as subtotal resections; in Group 2, 74.4% were performed as lobectomies and 25.6% as subtotal resections. No differences were found for reduced vocal cord function (2.4% vs. 1.9%, p = 0.746) and recurrent laryngeal nerve paralysis in the postoperative laryngoscopy (2.9% vs. 1.8%, p = 0.675). Postoperative hypoparathyroidism was detected in 13.66% in Group 1 and in 19.80% in Group 2 after bilateral resections (p = 0.037). There was no difference in the rate of reoperations for cancer between both groups (43.4% vs. 52.1%, p = 0.182). CONCLUSION: Surgical practice changed from subtotal to lobectomies for benign goiter over a period of 17 years without change in laryngeal nerve damage but with increasing rates of postoperative hypocalcemia.

Comparison of bipolar radiofrequency ablation zones in an in vivo porcine model: Correlation of histology and gross pathological findings.

BACKGROUND: Continuing research ex vivo and in vivo with animal models is performed to advance the oncological safety of radiofrequency ablation (RFA) of liver tumors. In these experiments, frequently imaging modalities (e.g. MRI or CT) or macro-morphological measurements are used to determine the full extent of the different ablation zones inside of RFA lesions. However, no systematic study has been performed so far, which verified the accuracy of the macro-morphological findings. Therefore, the present study aimed to correlate histological and gross pathological findings of bipolar radiofrequency ablation zones of porcine livers with regard to cell viability in vivo. METHODS: Bipolar RFA was performed in the liver of anaesthetized female domestic pigs under CT-guidance using an internally cooled 20 mm RFA applicator. Afterwards RFA cross sections of the liver were made in a perpendicular orientation to the applicator. Ablation zones were initially documented by photography and thereafter prepared for histological analysis. Latter was based on HE-staining and NADH-diaphorase cell viability staining. Micro- and macro-morphological sections were digitally analyzed along the cross-section area for statistical correlation. RESULTS: Three different RF ablation zones could be differentiated. A central zone showing no cell viability (white zone) was surrounded by a red zone. The red zone could be divided into an inner zone of viable and non-viable cells (red zone 1), followed by a zone of edema with mostly viable cells (red zone 2).Micro- and macro-morphological data showed a strong correlation for the white zone (r = 0.95, p < 0.01), the red zone 1 (r = 0.85, p < 0.01), and the red zone 2 (r = 0.89, p < 0.01). CONCLUSION: White zone and red zone could clearly be distinguished in gross pathology and histology after bipolar RFA of porcine liver tissue in vivo. The red zone could be differentiated into an inner zone of viable and non-viable cells and an outer zone with high cell viability and intercellular edema. A strong correlation of micro- and macro-morphology could be shown for all three ablation zones. With this knowledge, gross pathological examination can be used as a reliable indicator of lethally damaged tissue in bipolar RFA of in vivo porcine liver.