Paravertebral Block Plus Thoracic Wall Block versus Paravertebral Block Alone for Analgesia of Modified Radical Mastectomy: A Retrospective Cohort Study

Background and Objectives
Paravertebral block placement was the main anesthetic technique for modified radical mastectomy in our hospital until February 2014, when its combination with blocks targeting the pectoral musculature was initiated. We compared the analgesic effects of paravertebral blocks with or without blocks targeting the pectoral musculature for modified radical mastectomy.
Methods
We retrospectively collected data from a single surgeon and anesthesiologist from June 1, 2012, to May 31, 2015. Intraoperative sedatives and analgesic requirements, time to the first analgesic request, postoperative analgesic doses, patient satisfaction, and complications were compared.
Results
Fifty-four patients received a paravertebral block alone (PECS 0), and 46 received a paravertebral block combined with blocks targeting the pectoral musculature (PECS 1). The highest intraoperative effect–site concentration of propofol was significantly lower in the PECS 1 group than in the PECS 0 group [2.3 (1.5, 2.8) vs 2.5 (1.5, 4) μg/mL, p = 0.0014]. The intraoperative rescue analgesic dose was significantly lower in the PECS 1 group [0 (0, 25) vs 0 (0, 75) mg of ketamine, p = 0.0384]. Furthermore, the PECS 1 group had a significantly longer time to the first analgesic request [636.5 (15, 720) vs 182.5 (14, 720) min, p = 0.0001]. After further adjustment for age, body mass index, American Society of Anesthesiologists Physical Status classification, chronic pain history, incidence of a superficial cervical plexus block placement, and operation duration, blocks targeting the pectoral musculature were determined to be the only significant factor (hazard ratio, 0.36; 95% confidence interval, 0.23–0.58; p < 0.0001). Very few patients used potent analgesics including morphine and ketorolac; the cumulative use of morphine or ketorolac was similar in the study groups. However, the incidence of all analgesic use, namely morphine, ketorolac, acetaminophen, and celecoxib, was significantly lower in the PECS 1 group [3.5 (0, 6) vs 5 (0, 12), p < 0.0001].
Conclusions
Compared with the placement of a paravertebral block alone, combining blocks targeting the pectoral musculature with a paravertebral block for modified radical mastectomy reduced the sedative and analgesic requirements during operation and provided more effective postoperative analgesia.

研究背景与目的
2014年2月之前，我院改良根治性乳房切除术（modified radical mastectomy）的主要麻醉方式为单纯椎旁阻滞（paravertebral block），自该时间起，我院开始采用椎旁阻滞联合胸肌阻滞的麻醉方案。本研究旨在对比改良根治性乳房切除术患者接受单纯椎旁阻滞，与椎旁阻滞联合胸肌阻滞的镇痛效果。

研究方法
本研究回顾性收集了2012年6月1日至2015年5月31日期间，同一位外科医师与麻醉医师接诊的患者数据。比较两组患者的术中镇静剂与镇痛药物使用剂量、首次镇痛请求间隔时间、术后镇痛药物用量、患者满意度及并发症发生情况。

研究结果
54例患者接受单纯椎旁阻滞（PECS 0组），46例患者接受椎旁阻滞联合胸肌阻滞（PECS 1组）。PECS 1组患者的术中最高丙泊酚（propofol）效应室浓度显著低于PECS 0组[2.3(1.5, 2.8) vs 2.5(1.5, 4) μg/mL，p=0.0014]。PECS 1组的术中抢救性镇痛药物使用剂量显著更低[0(0,25) vs 0(0,75) mg氯胺酮（ketamine），p=0.0384]。此外，PECS 1组患者首次镇痛请求的间隔时间显著更长[636.5(15,720) vs 182.5(14,720) min，p=0.0001]。在对年龄、体重指数、美国麻醉医师协会身体状况分级（American Society of Anesthesiologists Physical Status classification）、慢性疼痛病史、颈浅丛阻滞实施率及手术时长进行校正后，结果显示胸肌阻滞是唯一具有显著统计学意义的影响因素（风险比0.36；95%置信区间0.23~0.58；p<0.0001）。两组患者中使用吗啡（morphine）、酮咯酸（ketorolac）这类强效镇痛药物的人数极少，且吗啡或酮咯酸的累计使用剂量无显著组间差异。但PECS 1组患者的全部镇痛药物（包括吗啡、酮咯酸、对乙酰氨基酚（acetaminophen）及塞来昔布（celecoxib））使用发生率显著更低[3.5(0,6) vs 5(0,12)，p<0.0001]。

研究结论
相较于单纯椎旁阻滞，改良根治性乳房切除术患者接受椎旁阻滞联合胸肌阻滞的麻醉方案，可降低术中镇静与镇痛药物的使用需求，并提供更为有效的术后镇痛效果。