Safety and Complications of Landmark-Based Paravertebral Blocks: A Retrospective Analysis of 979 Patients and 4983 Injections

Objective: This study aimed to determine the incidence of complications after landmark-based paravertebral blocks for breast surgery.

Methods: The medical records of patients that received a paravertebral block for breast surgery between 2019 and 2022 were reviewed. Patient age, gender, type of procedure, number of injections, volume of injected anesthetic, and possible complications were noted. A record was identified as a possible serious block-related complication if there was concern or treatment for local anesthetic systemic toxicity (LAST), pneumothorax, altered mental status, or intrathecal/epidural spread. Other complications recorded were immediate post-block hypotension and nausea/vomiting requiring treatment and unanticipated post-surgical admission. Patients receiving ultrasound guided paravertebral blocks were excluded from this study.

Results: Over a 3-year period, 979 patients received paravertebral blocks using the landmark technique for breast surgery, totaling 4983 injections. Overall, 6 patients required assessment for post-block issues (0.61%), including hypotension (2 patients), nausea (3 patients), and hypotension + altered mental status (1 patient). This latter patient was identified as having a serious complication related to the paravertebral block (0.1%). This patient had unintentional intrathecal spread and altered mental status that required mechanical ventilation. The incidence of block related hypotension and nausea requiring treatment was thus 0.31% and 0.31% respectively. Four patients required unanticipated admission, but none were for block-related reasons. No patients in this study were found to have LAST or pneumothorax.

Conclusion: Our study suggests that landmark based paravertebral blocks for breast surgery result in a very low complication rate and are a safe technique for post-surgical analgesia.