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Biomedical subjects

M L Fackler

Publications and source records attributed to M L Fackler.

52 records · Page 3Linked to original sources
PubMed1986

Ballistic injury.

Wound profiles made under controlled conditions in the wound ballistics laboratory at the Letterman Army Institute of Research showed the location along their tissue path at which projectiles cause tissue disruption and the type of disruption (crush from direct contact with the projectile or stretch from temporary cavitation). Comparison of wound profiles showed the fallacy in attempting to judge wound severity using velocity alone, and laid to rest the common belief that in treating a wound caused by a high-velocity missile, one needs to excise tissue far in excess of that which appears damaged. All penetrating projectile wounds, whether civilian or military, therefore should be treated the same regardless of projectile velocity. Diagnosis of the approximate amount and location of tissue disruption is made by physical examination and appropriate radiographic studies. These wounds are contaminated, and coverage with a penicillin-type antibiotic should be provided.

Humans↗
PubMed1986

Wounding mechanism of projectiles striking at more than 1.5 km/sec.

In 1976 Charters and Charters (2) described experiments intended to study effects of projectiles with a striking velocity greater than 1 km/sec. They postulated that the projectiles at higher velocity would cause shallow wounds with wide tissue destruction on the surface, especially when striking velocity exceeded the speed of sound in tissue (about 1.5 km/sec). We found no other studies reported dealing with projectiles in this velocity range, the conclusions and assumptions of Charters and Charters have been quoted by others and accepted as fact. We designed and performed experiments to test the hypothesis of Charters and Charters by comparing temporary cavity morphology and penetration in gelatin. We fired two types of blunt projectiles over a velocity range from 650 m/sec (2,137 ft/sec) to 2,016 m/sec (6,614 ft/sec). In these studies we found no evidence to indicate that shape and characteristics of the disruption in ordnance gelatin change significantly when missile striking velocity exceeds sonic speed in the target.

Forensic Medicine↗
PubMed1985

The wound profile: a visual method for quantifying gunshot wound components.

A wound profile method is reported for predicting the wounding potential of ordnance in living animal tissue by shooting projectiles into 10% gelatin blocks kept at a temperature of 4 degrees C. Blocks (25 X 25 X 50 cm) were placed end to end so that the entire missile-gelatin interaction was captured. The penetration and fragmentation pattern in these blocks previously was found comparable to wounds in living swine leg muscle. The extent of the radial cracks in the gelatin approximated the temporary cavity size in swine muscle. Measurements from longitudinal sections of the blocks indicated the depth of penetration and the sizes of both the permanent and temporary cavities, and fragmentation patterns were mapped from biplanar X-rays of the blocks. The four wound components, penetration, fragmentation, permanent cavitation, and temporary cavitation, were diagrammed in what was termed a 'wound profile.' This profile should help characterize wounds caused by different missiles.

Gelatin↗
PubMed1984

Wounding potential of the Russian AK-74 assault rifle.

The Russian contribution to the new generation of smaller caliber assault rifles is the AK-74, whose 5.61-mm (diameter), 3.4-gm (weight), 2.5-cm (length) aerodynamically shaped bullet has a muzzle velocity of 900 m/s. Our tests show that in living swine soft tissues and gelatin tissue simulant the AK-74's copper-plated steel jacket resists fragmentation or deformation. Since the bullet does not fragment, the tissue disruption surrounding the bullet pathway is limited to the stretching effect of temporary cavitation. We present evidence indicating that the energy used during temporary cavity formation causes limited permanent tissue disruption in the more elastic soft tissues (muscle, bowel wall, lung); the same insult in the relatively nonelastic liver, however, causes multiple fractures and massive permanent disruption. We conclude that the AK-74, despite its rather high velocity and marked tendency to yaw soon after penetration, causes relatively nondramatic wounds due to its nonfragmenting behavior.

Abdominal Injuries↗
PubMed1984

Bullet fragmentation: a major cause of tissue disruption.

Effects of nonfragmenting solid brass bullets (5.56 mm, 3.1 gm, 1.9 cm long, machine-made at Letterman Army Institute of Research) and fragmenting soft-point bullets (5.56 mm, 3.2 gm, 1.7 cm long, commercially made by Hornady Manufacturing Co., Grand Island, NE) were compared when they were fired through soft tissue of the hind legs of five live swine (50 to 70 kg). The swine were anesthetized endotracheally (0.8% halothane) and placed in the supine position with the hind legs extended. Blocks of tissue simulant (10% gelatin at 4 degrees C, molded in blocks 20 X 22 X 47 cm) were placed against the skin at the predicted point of bullet exit. All shots (a fragmenting bullet through one hind leg and a nonfragmenting bullet through the other hind leg of each swine) were fired at a range of 3 m from a rifle with a bullet tract at 90 degrees to the long axis of the swine's body. Bullet velocities ranged from 930 to 990 m/s. Dissections of the bullet tract (through tissue and gelatin) revealed that tissue disruption from the fragmenting bullets was significantly greater (p less than 0.001) than from nonfragmenting bullets. The recovered bullets were weighed. The results showed that the fragmenting bullet lost 59 to 77% of its original weight and the nonfragmenting bullet was the same weight as originally. Recognition of the amount of tissue disruption and identification of bullet fragments in the wounds resulting from the two different bullets should be a useful guide to operating surgeons in selecting the best approach for treatment of gunshot injuries.

Animals↗
PubMed1975

Extending the usefulness of self-retaining retraction.

Self-retaining retractors are a great aid in surgery since they assist in obtaining and maintaining the exposure necessary to accomplish the goal of surgery. The purpose of this retractor-retaining ring and clamp set is to increase the versatility of the self-retaining retractor and to make its advantages more generally available by a drastic reduction in cost. This is accomplished by using a simple, easily obtained clamp that can be adapted to the retractors presently available in any operating suite in combination with any of the three ring sizes to produce a self-retaining retractor that can easily accommodate variables such as the size of the patient and the type of operation.

Appendectomy↗