The Analgesic Effects of the Thoracic Paravertebral Block on Post-percutaneous Nephrolithotripsy: A Retrospective Study.

INTRODUCTION: Percutaneous nephrolithotripsy (PCNL) is a minimally invasive procedure for treating large and complex kidney stones, often resulting in significant post-operative pain and increased opioid use. This study aims to compare pain scores between patients undergoing PCNL who did and did not receive a preoperative single-shot thoracic paravertebral block (PVB) at the post-anesthesia care unit (PACU) as the primary outcome. Secondary outcomes were patient-controlled analgesia (PCA) usage on post-operative day 1 (POD 1), total opioid consumption on PACU and POD 1, and post-operative nausea and vomiting (PONV). METHODS: A retrospective cohort study was conducted on the medical records of 341 patients who underwent PCNL from July 2014 to April 2016 in a single major academic center. PVB was administered at thoracic levels T7-9 using a volume of 20 cc of bupivacaine, ranging from 0.25% to 0.5%, to achieve the desired analgesic effect. RESULTS: After excluding 34 patients, the study included 123 in the no block (NB) group and 149 in the regional anesthesia (RA) group. There were no differences in demographics, including age, sex, weight and height, BMI, and indication for PCNL. The results revealed that the RA group experienced a statistically significant reduction in PCA usage in both crude and adjusted models (adjusted logistic regression analysis: OR = 0.19, 95% CI = 0.05-0.60; p = 0.008). However, there were no significant changes in total opioid consumption, pain scores, or incidents of PONV. CONCLUSION: The retrospective analysis did not reveal any discernible advantage in pain management associated with the use of PVB for post-PCNL analgesia, except for reducing the percentage of PCA narcotics used. Future investigations with larger sample sizes and meticulous control for surgical indications and complexity are imperative to accurately assess the efficacy of this block in the context of post-PCNL surgery.

Anesthetic Considerations for Functional Neurosurgery.

Functional neurosurgery is a rapidly growing field that uses surgical resection, ablation, or neuromodulation to treat an assortment of neurologic and psychiatric disorders, the most common of which are movement disorders and epilepsy. Anesthesiologists caring for patients undergoing neurofunctional procedures should be aware of the anesthetic implications of patients' underlying disease as well as procedure-specific concerns, such as the effects of anesthetics on intraoperative neuromonitoring and limited access to patients due to stereotactic frames or intraoperative imaging.

Is a Retrolaminar Approach to the Thoracic Paravertebral Space Possible?: A Human Cadaveric Study.

BACKGROUND AND OBJECTIVES: The retrolaminar block (RB) is used for truncal analgesia, but its mechanism of neural blockade remains obscure. We sought to learn the pattern of local anesthetic spread after thoracic RB using cadaveric models. METHODS: In 8 fresh cadavers, an ultrasound-guided T4 RB was performed with 20 mL of methylene blue 1% and bupivacaine 0.5%. For comparison, an RB at T9 in 1 cadaver and a T4 thoracic paravertebral block in another cadaver were performed. Subsequently, posterior and anterior thoracic dissections were performed to examination where the dye spread. RESULTS: After T4 RB, dye was noted to spread in the ipsilateral retrolaminar plane (all 8 cadavers, median cephalad spread 3.5 cm, caudad spread 10.7 cm, lateral spread 2.5 cm), the contralateral retrolaminar plane (6 cadavers), the paravertebral space (5 cadavers, median of 3 segments, T3-T5), the intercostal space (5 cadavers, median of 3.5 cm laterally), the T4 epidural space (6 cadavers), and the intervertebral foramina (4 cadavers, median of 2 segments, T4-T5). After T9 retrolaminar injection, dye was noted in the ipsilateral retrolaminar plane (5.5 cm cephalad, 13.5 cm caudad, and 2.5 cm lateral), the contralateral retrolaminar plane, and the epidural space. Dye after T4 traditional paravertebral block spread to T1-T6 paravertebral space with 15-cm lateral spread. CONCLUSIONS: Injectate spread to the paravertebral space, epidural space, intercostal space, and intervertebral foramina is possible in the RB but is quite variable. In comparison to the thoracic paravertebral block, injectate spread within the paravertebral space is more limited.