Biomechanical analysis of acute subdural hematoma resulting from judo

Abstract

This study investigated biomechanical mechanisms of acute subdural hematoma caused by judo and sought preventive measures to reduce injury. A Japanese judo expert repeatedly threw an anthropometric test device using two throwing techniques, Osoto-gari and Ouchi-gari. Linear and angular accelerations of the head were measured. Both throwing techniques resulted in the dummy falling backwards, with the occipital area of the head contacting the mat, and peak linear and angular accelerations being observed when the head contacted the mat. For linear acceleration, the posterior-anterior direction showed the greatest force (41.0 ± 2.6 G using Osoto-gari, and 86.5 ± 4.3 G using Ouchi-gari). For angular acceleration, values for sagittal plane rotation were greatest among the three directions measured (3315 ± 168 rad/s 2 using Osoto-gari, and 1328 ± 201 rad/s 2 using Ouchi-gari). We concluded that occipital head contact produced the most forceful longitudinal linear and sagittal plane angular accelerations; subsequent stretches and ruptures of parasagittal bridging veins resulting in acute subdural hematoma. As severe head injuries can result if a person's head comes into contact with the mat, offensive throwing techniques should be restricted to participants able to sufficiently demonstrate the Ukemi technique.

Biomechanical Analysis of the Head Movements of a Person Thrown by the Judo Technique ‘Seoi-nage’

“…From the viewpoint of injury prevention, the most important measure is avoidance of direct head contact with the tatami. As shown in current and our previous [5][6][7] study results, the head acceleration sharply increases when the head hits the tatami. In other words, the impact on the head is essential for veins' disruption.…”

“…This phenomenon differs from the head injuries sustained by judokas thrown by Osoto-gari or Ouchi-gari, in which the occipital head of the thrown judoka contacts the tatami and subsequently causes greater linear acceleration in the longitudinal direction and greater angular acceleration in the sagittal plane. 5) Acute subdural hematoma often occurs due to falls, motor vehicle collisions, and assault, as a result of the head directly impacting a rigid surface. 13) At the moment of impact, the head undergoes both linear and angular acceleration, and the large angular acceleration plays an important role in the occurrence of ASDH.…”

“…The purpose of the present study was to use an anthropomorphic test device (ATD) to examine the kinematics and biomechanical parameters of the head when a judoka is thrown forward by Seoi-nage. Additionally, we clarified the head injury mechanisms due to Seoi-nage compared with the other throwing techniques evaluated in our previous study, [5][6][7] and proposed effective measures for preventing such injuries.…”

Effects of Different Throwing Techniques in Judo on Rotational Acceleration of Uke's Head

“…The maximum rotational acceleration generated was 3315 rad/s 2 with osotogari and 1328 rad/s 2 with ouchi-gari. These accelerations were su‹ciently lower than those produced in the study by Hitosugi et al (2014). This disparity was greatly aŠected by the presence or absence of head bruising.…”

“…In contrast, Hitosugi et al (2014) conducted an experiment in which a judo expert threw an anthropometric test device via osoto-gari and ouchigari. They then measured the rotational acceleration of the head of an anthropometric test device during each throwing technique.…”