Horner Syndrome Following Intercostal Nerve Block Via an Anterolateral Approach in Breast Lumpectomy: A Prospective Nested Case-control Study.

BACKGROUND:Lumpectomy is important for preventing malignant changes in benign tumors and diagnosing malignant tumors. Intercostal nerve blocks (ICNBs) are useful for breast lumpectomy as either the primary anesthetic or as an adjuvant anesthetic procedure. To our knowledge, no studies have evaluated the association between Horner syndrome and ICNB. OBJECTIVES:This study aimed to explore the characteristics of and related risk factors for Horner syndrome after ICNB. STUDY DESIGN:A prospective, nested case-control study. SETTING:Fudan University Shanghai Cancer Centre from April 2020 through July 2020. METHODS:Patients scheduled for breast lumpectomy under ICNB from April 2020 through July 2020 in our hospital were recruited. The ICNB was introduced at the intersection of the midaxillary line and the inferior border of the ribs, according to the location of the mass. Horner syndrome indicators were assessed one, 5, 10, 15, 30, 45, and 60 minutes and 3, 6, 12 and 24 hours after ICNB. Personal data (age, body mass index [BMI], ASA classes), data on anesthetic (the puncture points, dose of local anesthetics, duration of ICNB, Horner syndrome indicators, other complications) and data on postoperative recovery (postoperative activity time, postoperative feeding time) were recorded. Univariate and multivariate logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals. RESULTS:Ipsilateral Horner syndrome was found in 35 of 998 (3.5%) patients. Ipsilateral miosis, the first symptom to appear and last to disappear, occurred within 4 minutes and lasted 45 minutes to 240 minutes after ICNB. Seven patients showed obvious ipsilateral facial flushing. Logistic multivariate regression analysis showed that independent risk factors for Horner syndrome after ICNB were age <= 45 years, body mass index <= 18.5 kg/m2, and the need for a second ICNB. LIMITATIONS:Firstly, the patients in this study are all adult women, and the applicability of other populations is uncertain. Secondly, the flow trajectory of local anesthetics was not confirmed by imaging tracers. CONCLUSIONS:ICNB via an anterolateral approach promoted enhanced recovery after breast lumpectomy. The incidence of Horner syndrome following ICNB for breast lumpectomy was 3.5%. Horner syndrome occurred on the ipsilateral side of the ICNB and was reversible. Younger age, lower BMI, and the need for a second ICNB were risk factors for Horner syndrome after ICNB. KEY WORDS:Horner's syndrome, intercostal nerve block, breast lumpectomy, enhanced recovery.