Effects of Revision Surgery and Surgical Margins on Outcome of Peripheral Soft Tissue Sarcomas: Experience from a Tertiary Cancer Care Centre.

INTRODUCTION: The purpose of this study is to assess the impact of revision surgery, after unplanned excision, on oncological outcome and surgical morbidity in soft tissue sarcomas and also to assess the relation between margin status and oncologic outcome. MATERIALS AND METHODS: We undertook a retrospective analysis of prospectively maintained database of 153 patients with peripheral soft tissue sarcomas treated in our institute from 2006-2010. RESULTS: Postoperatively, 111(72.5%) patients had negative margins, 20(13.1%) had close margins and 22(14.4%) had planned positive margins. Local recurrence rate was 19.8% in patients with negative margins and 28.6% for patients with close or positive margins (p= 0.007). There was no statistically significant difference in rates of distant metastases (18.9% vs 21.4%, p value 0.56) and five-year overall survival (82.5% Vs 79.8%, p value 0.41) between margin negative and close/positive groups. The five-year overall survival rates were 80.4 vs 77.8% (p =0.42) and five-year disease-free survival rates were 72.4% vs 70.2% (p=0.3), in the revision surgery group and primary surgery group respectively. CONCLUSION: Margin status after excision of soft tissue sarcoma is not a direct predictor for overall survival or distant metastasis. Revision surgery after an unplanned excision does not carry worse survival compared to primary surgery group.

Lomb algorithm versus fast Fourier transform in heart rate variability analyses of pain in premature infants.

Heart rate variability analysis is a promising method for measuring pain in premature infants. The Lomb algorithm was adapted and compared with fast Fourier transform (FFT) for the purposes of PSD estimation. Both FFT and the Lomb algorithm had similar low frequency (LF) estimation error rates. However, the Lomb algorithm had a significant smaller error rate than FFT when estimating high frequency (HF). In addition, the ECG signals of two premature infants in the newborn intensive care unit were analyzed while undergoing a routine heel stick, a common painful procedure. The Lomb algorithm performed as expected marking a decrease in both LF and HF power in the presence of pain.