This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hanks, R. K. Articles by Klein, S. M. Search for Related Content PubMed PubMed Citation Articles by Hanks, R. K. Articles by Klein, S. M.

---

REGIONAL ANESTHESIA

The Effect of Age on Sciatic Nerve Block Duration

R. Kyle Hanks, BS^*, Ricardo Pietrobon, MD, PhD, Karen C. Nielsen, MD, Susan M. Steele, MD, Marcy Tucker, MD, PhD, David S. Warner, MD, Kathryn P. King, MD, and Stephen M. Klein, MD

*School of Medicine, and Departments of Anesthesiology and Surgery, Duke University Medical Center, Durham, North Carolina

Address correspondence and reprint requests to Stephen M. Klein, MD, Box 3094, Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710. Address e-mail to klein006{at}mc.duke.edu.

The physiologic changes that occur with advancing age and their effect on the duration of peripheral nerve blocks have yet to be defined. We prospectively studied the duration of sciatic nerve block using mepivacaine in younger and older patients. Eighty ASA physical status I-III patients, aged 18–35 (n = 40) or 55–80 (n = 40) yr, having outpatient knee arthroscopy with a femoral block and a standardized sciatic nerve block were enrolled; 37 in each group completed the study. All patients received a Labat sciatic nerve block using 20 mL of 1.0% mepivacaine with 0.1 mEq/mL sodium bicarbonate and 1:400,000 (2.5 µg/mL) epinephrine and a femoral nerve block. The duration of sensory block (sensation of pinprick, temperature, and vibration), motor block (plantar and dorsi flexion), and complete sensory and motor block in the sciatic nerve distribution of the operative extremity were measured. The time for complete return of both sensory and motor function was longer in the older group, 329 ± 47 min compared with 306 ± 46 min (mean ± sd) in the younger group (P = 0.04). The difference was small under the conditions of this study and would not be perceived clinically. Age also increased the time to return of vibratory sensation (younger = 292 ± 58 min, older = 257 ± 50 min; P = 0.007). The other measurements did not differ between groups. We conclude that age may affect peripheral nerve blocks and that more investigation is needed to determine the pharmacologic, physiologic, and chronologic factors behind these findings.