Standard versus video-assisted thyroidectomy: objective postoperative pain evaluation

Background: This prospective, randomized study was designed to objectively demonstrate that minimally invasive video-assisted thyroidectomy (MIVAT) improves postoperative pain compared with standard thyroidectomy, via the dosage of biochemical mediators measured before and after surgery. Methods: Forty-nine patients undergoing total thyroidectomy were allotted to MIVAT (n = 23) or traditional thyroidectomy (OPEN) (n = 26) groups. At hospitalization (T0), interleukin (IL)-1, -2, -4, -6, -10, -3, tumor necrosis factor (TNF)-α, TGF-β, and MCP-1 were measured. The basal pain tolerance also was evaluated by VAS. Blood samples for interleukin measurement and VAS evaluations were obtained from all patients in the recovery room (T1) and 24 h after surgery (T2). Results: At T0, the MIVAT and the OPEN groups were not different in terms of basal pain tolerance and biochemical profile. At T1, VAS scores were significantly higher (p = 0.04), whereas TGF-β (p = 0.03) and MCP-1 (p = 0.03) levels were significantly lower in the OPEN than in the MIVAT group. No significant difference was demonstrated for other interleukins. A significant inverse relationship between VAS and TGF-β was demonstrated and confirmed through the correlation (p = 0.003) and regression (p = 0.003, p < 0.0001, R 2 = 0.172) coefficients; the stepwise regression also demonstrated that TGF was the most predictive factor of postoperative pain (p = 0.0038) through an inverse relationship. No statistically significant difference has been demonstrated at T2. Conclusions: TGF-β serum levels immediately after surgery seem to correlate with pain evaluation, confirming that reduced postoperative distress is an objective outcome of MIVAT. This result confirms the results of studies based only on subjective pain evaluations.