Fahy, A.S., Jakub, J.W., Dy, B.M., Eldin, N.S., Harmsen, S., Sviggum, H., & Boughey, J.C. (2014). Paravertebral blocks in patients undergoing mastectomy with or without immediate reconstruction provides improved pain control and decreased postoperative nausea and vomiting. Annals of Surgical Oncology, 21, 3284–3289. 

To evaluate whether paravertebral block use affected opioid use, antiemetic use, and length of stay in patients receiving mastectomies

Patient data were collected from medical records from the time periods before and after the use of paravertebral blocks (PVBs). Patients receiving unilateral mastectomies had unilateral PVBs, and those receiving bilateral mastectomies had bilateral PVBs. Blocks were placed preoperatively. All patients had general anesthesia. Prophylactic opioids and antiemetics were given intraoperatively at the discretion of the anesthesia team. Pain scores were documented with vital sign monitoring postoperatively. The results of those who had PVBs were compared to a cohort of patients who did not have PVBs.

• N = 526  
• MEAN AGE = 56.5 years (range = 20–97 years)
• FEMALES: 100%
• KEY DISEASE CHARACTERISTICS: All had breast cancer, and slightly less than half had unilateral mastectomy; about half had immediate reconstruction
• OTHER KEY SAMPLE CHARACTERISTICS: 75% did not have axillary lymph nodes removed

• SITE: Single site  
• SETTING TYPE: Inpatient    
• LOCATION: Rochester, NY

• PHASE OF CARE: Active antitumor treatment

Retrospective cohort comparison

• Total postoperative opioid consumption
• Length of stay less than or greater than 36 hours
• Length of time in the postanesthesia care unit

In a multivariate analysis that was controlled for age and surgeon, there was no significant difference between groups in length of stay. The percentage of patients requiring antiemetics was higher in the no-PVB group (57 versus 39%, respectively, p < 0.00001). The amount of opioids required was higher in the no-PVB group on the day of surgery (47.6 versus 40.1 morphine equivalents, respectively, p < 0.0001). Despite differences in opioid consumption, there were no significant differences between groups in pain scores. The greatest difference in opioid consumption was seen in patients receiving immediate bilateral reconstructions.

The use of PVBs in patients receiving mastectomies was associated with lower antiemetic and opioid consumption on the day of surgery.

• Risk of bias (no random assignment)
• Key sample group differences that could influence results 
• Measurement/methods not well described 
• Other limitations/explanation: The method of pain measurement and the actual timing of measurement was not described. It appeared that the analysis was done in terms of opioid consumption for only the day of surgery. The analysis did not take into account any prophylactic antiemetics or opioids given intraoperatively. No description or standardization of all relevant postoperative medications was given.

The findings of this study suggested that among patients receiving mastectomies, PVBs may reduce the need for postoperative antiemetics and opioids. However, it was not clear that the procedure actually reduced postoperative pain. This procedure appeared to be most beneficial for women having the most extensive surgical procedures. Additional well-designed research is warranted to determine the clinical benefits of PVB and its role in improving perioperative pain control.