Strength testing of the human olfactory nerve at the frontal skull base

Abstract

Olfactory dysfunction may influence the quality of life tremendously. This study investigated the strength of the human olfactory nerve at the frontal skull base using cadavers. A total of 180 olfactory nerves were examined in 90 human cadaveric heads. The cut edges of the olfactory nerves were pulled until they were pulled out from the skull base. In the first set of 30 cases, each right olfactory nerve was pulled 0° laterally and 0° upward, and each left olfactory nerve was pulled 0° laterally and 15° upward. In the second set of 30 cases, each right olfactory nerve was pulled 0° laterally and 15° upward, and each left olfactory nerve was pulled 15° laterally and 15° upward. In the third set of 30 cases, each right olfactory nerve was pulled 15° laterally and 15° upward, and each left olfactory nerve was pulled 30° laterally and 15° upward. The strength of the olfactory nerve was measured when pulled in each direction. There was no significant difference in the strength of the olfactory nerves when pulling them in the postero-upward direction between 0° and 15° upward. The strengths of the olfactory nerves when pulling them in the postero-lateral direction 0° and 15° laterally were 3.14±1.87 and 4.05±1.70 g (mean ± standard deviation [SD]), respectively; the difference was almost significant. The olfactory nerve could be pulled more laterally than posteriorly because the retraction force is absorbed by the lateral wall of the olfactory fossa.

Effectiveness of olfactory training on different severities of posttraumatic loss of smell

“…1 The more serious the injury, the more often disturbances in smell functionality exist. 2,3 Several mechanisms may lead to olfactory impairment, including 1) Injuries of the nose and facial bones leading to damage of the olfactory epithelium, 4,5 2) lesions of olfactory bulb (OB) or the fila olfactoria, [6][7][8] or 3) damage to central structures. 3,9 Olfactory impairment from severe brain trauma puts patients in life-threatening conditions.…”

Managing Post-traumatic Olfactory Disorders

“…For example, the antero-posterior movement of the brain in relation to the skull base is commonly seen following motor vehicle accidents or ground-level falls to the occipital area. A cadaveric study indicated that frontal lobe retraction in a posterior direction from the olfactory bulb, regardless of angle from the skull base, is associated with high risk of olfactory nerve damage [12]. In addition, previous studies showed that an occipital injury is more likely to cause olfactory dysfunction than a frontal one [13,14].…”

Supraorbital Keyhole Approach for Intracranial Aneurysms : Transitioning from Concerns to Confidence

“…3). Retraction of the anterior part of the olfactory tract is considered more likely to produce avulsion of the olfactory nerve from the cribriform plate 2,31) . Thus, while the basic surgical procedures are similar, the direction of the brain retraction and surgical perspective are actually different between a supraorbital keyhole approach and pterional approach.…”