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Biomedical subjects

M L Fackler

Publications and source records attributed to M L Fackler.

At least 37 records · Page 2Linked to original sources
PubMed1990

Wounding effects of the AK-47 rifle used by Patrick Purdy in the Stockton, California, schoolyard shooting of January 17, 1989.

The limited disruption produced in tissue simulant by the rifle and bullets used in the Stockton, California, schoolyard shooting is entirely consistent with the autopsy reports on the five children who died of their wounds. It is also entirely consistent with well-documented battlefield studies and with previous tissue-simulant studies from many laboratories. It is inconsistent with many exaggerated accounts of assault-rifle wounding effects described by the media in the aftermath of this incident. This information should be documented for the historical record. However, the critical reason for correcting the misconceptions produced by media reaction to this incident is to prevent inappropriate gunshot-wound treatment.

Aorta↗
PubMed1990

Gunshot wounds: 1. Bullets, ballistics, and mechanisms of injury.

The nature and severity of a bullet wound depend on the characteristics of the bullet and of the tissues through which it travels. In addition to the mass and velocity of the bullet, its orientation and whether it fragments or deforms affect the nature of the wound. Two major mechanisms of wounding are described: crushing and stretching of tissue. Understanding the mechanisms by which bullets disrupt tissue can help physicians to evaluate and treat wounds.

Firearms↗
PubMed1990

Gunshot wounds: 2. Radiology.

Radiologists can contribute substantially to the evaluation and treatment of the patient with a gunshot wound. Plain films, CT, angiography, and sometimes MR imaging are used to localize the missile, determine what path it followed in the body, assess missile and bone fragmentation, and identify missile emboli. If the peritoneal cavity was entered by a bullet, a laparotomy is required. Missiles subject to magnetic forces can complicate MR imaging. Certain locations of missile fragments predispose to lead poisoning or lead arthropathy. Angiography is useful for both diagnosis and treatment. Both angiographic hemostasis and percutaneous foreign body removal may be used.

Angiography↗
PubMed1990

Wound ballistics: the management of assault rifle injuries.

Studies in our wound ballistics laboratory have shown that excellent healing can occur in complicated assault rifle wounds that are free of tension and well drained. A conservative approach to debridement and excision of tissue in uncomplicated extremity wounds may be a valid and resource-saving technique.

Animals↗
PubMed1989

Open wound drainage versus wound excision in treating the modern assault rifle wound.

Military dogma of the past 20 years preaches that excision of all injured tissue around the path of a penetrating projectile is essential in wound treatment. To find out whether excising injured muscle surrounding a bullet path benefits healing over and above the benefit provided by a simple release of tension by incision, two groups of 90 kg swine were shot in the hind leg with a replica of the AK-74 assault rifle projectile. One group was treated by excision of injured tissue around the projectile path; in the other group no tissue was excised. Both groups were given parenteral penicillin for 5 days, and simple gauze dressings were used to cover the wounds. No difference in healing time occurred; the wounds in both groups had closed, and no epithelial defect remained by 20 to 22 days. These results indicate that the simple extremity wound caused by the modern-generation assault rifle, provided with adequate open drainage and systemic penicillin, heals as rapidly when the body defense mechanisms handle the disrupted tissue as when an attempt is made to excise it surgically.

Animals↗
PubMed1988

Wound ballistics. A review of common misconceptions.

Attempts to explain wound ballistics (the study of effects on the body produced by penetrating projectiles) have only succeeded in mystifying it. This review explains the projectile-tissue interaction and presents data showing the location, type, and amount of tissue disruption characteristically produced by various projectiles. Data on tissue disruption are presented graphically as wound profiles. The major misconceptions in the field are listed, analyzed, and disentangled. Failure in adhering to the basic precepts of scientific method is the common denominator in all of the listed misconceptions; the result has been diversion of attention from the element essential to understanding and properly treating the gunshot wound--objective evaluation of the wound itself.

Animals↗
PubMed1988

The wound profile: illustration of the missile-tissue interaction.

The wound profile was developed at the Letterman Army Institute of Research in order to measure the amount, type, and location of tissue disruption produced by a given projectile, and to present the data in a standardized, easy to understand picture. The entire missile path is captured in one or more 25 X 25 X 50 cm blocks of 10% ordnance gelatin at 4 degrees C. The penetration depth, projectile deformation and fragmentation pattern, yaw, and temporary cavity of the missile in living anesthetized swine muscle are reproduced by this gelatin. Measurements are taken from cut sections of the blocks after mapping of the fragmentation pattern with biplanar X-rays. These data are then reproduced on a life-sized wound profile which includes a scale to facilitate measurement of tissue disruption dimensions, a drawing of the loaded cartridge case before firing, the bullet weight and morphology before and after firing (and calculated percent of fragmentation), and the striking velocity. This technique allows us to determine the wounding character of the projectile without the need for elaborate and expensive high-speed cine and X-ray equipment, or the need for shooting live animals. The method improves our understanding of the wounding process and should lay the groundwork to assure more rational and effective treatment.

Firearms↗
PubMed1988

A reconsideration of the wounding mechanism of very high velocity projectiles--importance of projectile shape.

In 1976 a paper appeared which forecast "significant increases in velocities of projectiles from guns and fragments from warheads." It was postulated that the higher velocity projectiles 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). Other studies have not dealt with projectiles in this velocity range; the conclusions and assumptions stated in this 1976 paper have been quoted by others and accepted as fact. In a previous study, we shot blunt fragments into gelatin, but our findings did not support the proposed hypothesis that temporary cavity shape in tissue changes at velocities above the sonic speed. The temporary cavity becomes larger with increasing velocity but it does not become shallow unless the projectile fragments on impact. In the present study, we shot a series of blunt projectiles into animal tissue at velocities of 764 to 2,049 m/s. The stellate skin and muscle disruption splits from temporary cavity stretch we observed in this study are not apparent on entrance wounds from individual explosive device fragments in the living wounded. We suggest, therefore, that studies using blunt projectiles at striking velocities above 700 m/s are lacking in clinical relevance. We also compared wounds produced by pointed projectiles with those produced by blunt projectiles. The marked difference in wound morphology showed the fallacy of doing a study with blunt missiles and applying conclusions from that study to tissue disruption caused by all projectiles.

Animals↗
PubMed1988

Internal deformation of the AK-74; a possible cause for its erratic path in tissue.

A series of 20 shots with the AK-74 Russian Assault Rifle, in which the entire course of the bullet was captured in gelatin, showed a change in direction of the bullet track approximating a right angle in every case. Bullets were recovered from the gelatin for ten consecutive shots of this series and examined roentgenographically. In all cases an internal deformation was discovered to have taken place: lead from the bullet's core flowed into the air space inside the bullet's tip. The roentgenograms also showed that this flow of lead resulted in an asymmetrical bullet in every case. We suggest this resulting bullet imbalance as a possible cause of the unusually marked curve in this bullet's path through tissue.

Firearms↗
PubMed1988

Ordnance gelatin for ballistic studies. Detrimental effect of excess heat used in gelatin preparation.

Most users of ordnance gelatin for ballistics studies are apparently unaware of the detrimental effects on this tissue simulant's properties caused by excess heating in reconstitution of the gelatin powder. Material published by the Gelatin Manufacturers Institute of America states that heating gelatin above 40 degrees C can be detrimental to its properties. The manufacturer of type 250 A Ordnance Gelatin does not include directions for preparation with the gelatin powder. Directions that can be obtained by contacting the manufacturer fail to give any recommendations on the amount of heat applied during gelatin preparation and do not mention the detrimental effects of excess heat. These oversights are corrected in the revised set of directions included in this article.

Forensic Medicine↗