Ilioinguinal-inguinal nerve block for hernia repair.

To the Editor: A recent article (1) and editorial (2) describing ilioinguinal-iliohypogastric nerve block (IHNB) for inguinal hernia repair, while thought provoking, is also troubling. The authors have performed a prospective randomized clinical trial (PRCT) and then presented the data as a retrospective study. Patients must grant informed consent to be randomized. A human subject committee (often called an IRB) should review the trial before the beginning of the study.

There are several other study designs that have a sounder ethical basis than the approach taken by Yilmazlar et al. First, one can describe the alternative treatments to the patient. The investigator states that on the basis of current medical knowledge, we do not know which treatment is better. Therefore, the patient should select the therapy which sounds best. The patient is informed that in the future, the data will be reviewed to try to determine which therapy is really better. Naja et al (3) have published a study of anesthesia techniques for hernia repair where treatment allocation was based on patient choice.

A second ethical approach is to seek experiments of nature. For example, physician A feels that in his experience, spinal anesthesia for hernia is followed by an unacceptable rate of postdural puncture headache (PDPH) and urinary retention. The only regional technique that physician A offers to his patients is IHNB. Physician B feels that IHNB has a 20 to 30% failure rate. Physician B only offers his patients spinal anesthesia. Both physicians have a sound basis in the literature and their personal experience to justify their positions. The regional block that the patient receives will be determined by whether they are assigned to Dr. A or Dr. B, often a fairly random process. The IRB is asked to approve a retrospective review of the two therapies.

Finally, some very sophisticated designs have been proposed to reconcile randomization with patient choice and autonomy. (4) These designs may be impractical for most clinical researchers who lack formal biostatistical support.

Despite the ethical problems with the article, Dr. Wang's accompanying editorial is encouraging. (2) Ultrasound-guided IHNB may prove to be a very good anesthetic choice for inguinal hernia repair. (5,6) Nerve stimulator-guided paravertebral block (PVB) is another attractive option. (3,7) PVB provides the ideal triad: segmental anesthesia, good muscle relaxation, and prolonged analgesia. (8,9) PVB is not plagued by the common spinal anesthesia sequelae of PDPH and urinary retention.

The anesthesia community awaits a prospective randomized clinical trial comparing ultrasound-guided IHNB versus PVB. Which of these exciting new techniques will prove most efficacious and cost-effective for open inguinal hernia repair?

Richard K. Baumgarten, MD

References

1. Yilmazlar A, Bilgel H, Donmez C, et al. Comparison of ilioinguinal-iliohypogastric nerve block versus spinal anesthesia for inguinal herniorrhaphy. South Med J 2006;99:48-51.

2. Wang H. Is ilioinguinal-iliohypogastric nerve block an underused anesthetic technique for inguinal herniorrhaphy? South Med J 2006;99:15.

3. Naja MZ, el Hassan MJ, Oweidat M, et al. Paravertebral blockade vs general anesthesia or spinal anesthesia for inguinal hernia repair. Middle East J Anesthesiol 2001;16:201-210.

4. Millat B, Borie F, Fingerhut A. Patient's preference and randomization: new paradigm of evidence-based clinical research. World J Surg 2005;29:596-600.

5. Willschke H, Marhofer P, Bosenberg A, et al. Ultrasonography for ilioinguinal/iliohypogastric nerve blocks in children. Br J Anaesth 2005;95:226-230.

6. Eichenberger U, Greher M, Kirchmair L, et al. Ultrasound-guided blocks of the ilioinguinal and iliohypogastric nerve: accuracy of a selective new technique confirmed by anatomical dissection. Br J Anaesth 2006;97:238-243.

7. Naja ZM, Raf M, El Rajab M, et al. Nerve stimulator-guided paravertebral blockade combined with sevoflurane sedation versus general anesthesia with systemic analgesia for postherniorrhaphy pain relief in children: a prospective randomized trial. Anesthesiology 2005;103:600-605.

8. Baumgarten RK, Wesen CA, Boccaccio JE. Regional anesthesia has a role in hernia surgery. World J Surg 2006;30:639-640.

9. Baumgarten RK, Greengrass RA, Wesen CA. Paravertebral block: the holy grail of anesthesia for hernia surgery? Anesth Analg 2007;104:207-209.

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