Paravertebral Block: the Holy Grail of Anesthesia for Hernia Surgery?

To the Editor: Hadzic et al. (1) report that paravertebral block (PVB) provides superior same-day recovery over general anesthesia (GA). The accompanying editorial (2) discounts the utility of PVB for herniorrhaphy. The editorial cites several series that report pneumothorax after PVB and concludes that the risk-benefit ratio is unfavorable. However, all of the series cited were with thoracic PVB, primarily for breast surgery. One should not conceptualize PVB as a single entity. Instead, PVB is a family of four, related blocks, each with its individual risk-benefit ratio: cervical, thoracic (T1–10), hernia region (T11-L2), and lumbar or psoas compartment (L2–5). There will always be small chance of pneumothorax in the thoracic region, whereas in the region used for hernia surgery (T11-L2), the risk of pneumothorax is minimal (3). The editorial’s assertion that PVB for hernia should be avoided because of the risk of pneumothorax is akin to saying that we should avoid axillary brachial plexus block because of the 0.5% incidence of pneumothorax with supraclavicular brachial plexus block! The editorial notes that PVB took significantly longer than induction of GA, presumably, delaying the start of surgery. The predominant modes of anesthesia delivery in the United States are: 1) Certified Registered Nurse Anesthetist-physician anesthesia care team and 2) the residentfaculty model. In both settings, the supervising physician should perform the PVB in the preoperative holding area 30–40 min before surgery. When the patient is taken to the operating room, the operative site is already numb, so, surgery can begin immediately. This parallel processing (4) is extremely efficient. The editorial criticizes the Hadzic et al. study for using an antiquated GA technique in the control group. However, the study group is also a bit dated. In the years since this study was performed, nerve stimulatorguided PVB has been described (3,5–8). Guided PVB may enhance the success rate of PVB in the inguinal region. With the nerve stimulator, the physician sees the muscles twitch, thus assuring that the operative site is blocked. Poorly treated pain after hernia surgery often leads to urinary retention (9), a common cause of delayed discharge (3%–5%). Many studies make no provision for pain relief in the GA control group (10). Hadzic et al. incorporated wound infiltration in their GA control group. Still, their PVB group voided significantly sooner than the GA controls. Similarly, Weltz et al. (11) reported no urinary retention after hernia repair with PVB. Unlike spinal anesthesia, PVB preserves lower extremity motor function, so the patient can ambulate soon after surgery. PVB avoids the three most potent stimuli for postoperative nausea and vomiting: GA, opioids, and under-treated postoperative pain. Conceptually, PVB offers the ideal triad for hernia surgery: unilateral, segmental anesthesia of the operative site, good muscle relaxation, and prolonged postoperative analgesia. Although, we agree with Dr. White that more high-quality clinical trials are needed, we are confidant that whenever anesthesia is involved at all (12,13), PVB will prove to be a technique of choice for hernia surgery.