Background and Goal of Study: Contraction of serratus anterior muscle (SAM) irritates damaged intercostal muscles and itself, and aggravates the pain after video assisted thoracoscopic surgery (VATS). We hypothesized that the relaxation of SAM by long thoracic nerve (LTN) block could help the pain relief after VATS for pneumothorax wedge resection.
Materials and Methods: The patients were randomly assigned to control group or block group from among patients undergoing VATS for pneumothorax wedge resection. Before anaesthesia induction, the patients in block group received a single injection of LTN block. The pain were evaluated using visual analogue scale (VAS) at before anaesthesia induction (T0), arrival at postanaesthetic care unit (PACU) (T1), every 10 minutes after arrival at PACU for 30 minutes (T2, T3 and T4), and 1 hr and 24 hr after discharge from PACU (T5 and T6). PACU stay and total amounts of the bolus dose of patient controlled analgesia (PCA) were measured.
Results: VAS at T0 and T6 was similar between two groups but VAS from T1 to T5 in block group was significantly lower than control group (T1: 36 ± 11 versus 48 ± 14, T2: 36 ± 11 versus 51 ± 15, T3: 35 ± 10 versus 52 ± 15, T4: 30 ± 7 versus 45 ± 17 and T5: 26 ± 5 versus 32 ± 5). PACU stay in block group was significantly shorter than control group (30 ± 14 minutes versus 54 ± 23 minutes). Total amounts of the bolus dose of PCA during PACU (1.6 ± 1.2 ml versus 3.9 ± 2.0 ml) and during 1 hr after discharge from PACU (0.5 ± 0.8 ml versus 1.7 ± 1.2 ml) in block group were significantly lower than control group but total amounts of the bolus dose of PCA from 1 hr after discharge from PACU to 24 hr after discharge from PACU (1.6 ± 1.4 ml versus 1.1 ± 1.3 ml) were similar in two groups.
Conclusion(s): LTN block could reduce the pain after VATS for pneumothorax wedge resection and PACU stay.
1. Ramamurthy S, Hickey R, Maytorena A, Hoffman J, Kalantri A. Long thoracic nerve block. Anesth Analg 1990; 71: 197-9.