Increased cutaneous nerve fibers in female specimens

Background: The control of pain is critical to performing surgery. All surgical procedures cause some degree of pain, and the ability to minimize pain often affects a patient's perception of surgical outcome. Although the development of surgery was boosted by the advent of anesthesia, inadequate pain control continues to plague modern medicine. The mechanism of pain induction is an important area of research in the health care industry. To date, few studies have demonstrated increased perception of pain and lower tolerance for pain in female patients when compared with male patients. The authors hypothesized about whether these differences were related to increased density of nerve fibers in female as compared with male patients. Methods: The density of nerve fibers at a specific location (the skin directly overlying the infraorbital nerve foramen) was measured to test this hypothesis. Twenty cadaver skin specimens (1 cm(2)) were harvested, prepared using immunohistochemistry (S-100 polyclonal antibody), and counted using 45X high-powered microscopy. Results: Female specimens (n = 10) demonstrated increased nerve fiber density (34 +/- 19 fibers/cm(2) skin) when compared with male specimens (n = 10; 17 +/- 8 fibers/cm(2) skin; p = 0.038). Conclusion: Although preliminary and limited in scope, these findings favor a physical (organic) rather than a psychosocial explanation for more pronounced pain perception in female patients.