Traumatic brain injuries constitute a significant portion of injury resulting from automotive collisions, motorcycle crashes, and sports collisions. Brain injuries not only represent a serious trauma for those involved but also place an enormous burden on society, often exacting a heavy economical, social, and emotional price. Development of intervention strategies to prevent or minimize these injuries requires a complete understanding of injury mechanisms, response and tolerance level. In this study, an attempt is made to delineate actual injury causation and establish a meaningful injury criterion through the use of the actual field accident data. Twenty-four head-to-head field collisions that occurred in professional football games were duplicated using a validated finite element human head model. The injury predictors and injury levels were analyzed based on resulting brain tissue responses and were correlated with the site and occurrence of mild traumatic brain injury (MTBI). Predictions indicated that the shear stress around the brainstem region could be an injury predictor for concussion. Statistical analyses were performed to establish the new brain injury tolerance level.

A Proposed Injury Threshold for Mild Traumatic Brain Injury

Background Surgical oncologists rely heavily on the histopathological assessment of surgical margins to ensure total excision of the tumor in patients with head and neck cancer. However, current techniques may not detect small numbers of cancer cells at the margins of resection or in cervical lymph nodes. Methods We used molecular techniques to determine whether clonal populations of infiltrating tumor cells harboring mutations of the p53 gene could be detected in histopathologically negative surgical margins and cervical lymph nodes of patients with squamous-cell carcinoma of the head and neck. Results We identified 25 patients with primary squamous-cell carcinoma of the head and neck containing a p53 mutation who appeared to have had complete tumor resection on the basis of a negative histopathological assessment. In 13 of these 25 patients, molecular analysis was positive for a p53 mutation in at least one tumor margin. In 5 of 13 patients with positive margins by this method (38 percent), the carcinom...

https://www.nejm.org/doi/pdf/10.1056/NEJM199502163320704

Molecular Assessment of Histopathological Staging in Squamous-Cell Carcinoma of the Head and Neck

Intracranial Pressure Dynamics During Head Impact

A review of histologic classification systems for grading of malignancy in squamous cell carcinomas of the head and neck region is presented. Reasons behind the varying results obtained in studies using histomorphologic grading schemes are presented and potential errors involved in this type of clinical research are discussed. Requirements for the study of correlations between malignancy grade scoring, and recurrence and survival rates are presented. These include factors as patient selection, clinical staging, and follow-up principles. Special attention must be given to treatment modalities, establishment of negative surgical margins and occurrence of regional lymph node and/or distant metastases.

Review of the literature and a recommended system of malignancy grading in oral squamous cell carcinomas.

A methodology is proposed for creating and animating computer generated characters which combines recent research advances in robotics, physically based modeling and geometric modeling The control points of geometric modeling deformations are constrained by an underlying articulated robotics skeleton These deformations are tailored by the animator and act as a muscle layer to provide automatic squash and stretch behavior of the surface geometry A hierarchy of composite deformations provides the animator with a multi-layered approach to defining both local and global transition of the character's shape The muscle deformations determine the resulting geometric surface of the character This approach provides independent representation of articulation from surface geometry, supports higher level motion control based on various computational models, as well as a consistent, uniform character representation which can be tuned and tweaked by the animator to meet very precise expressive qualities A prototype system (Critter) currently under development demonstrates research results towards layered construction of deformable animated characters

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Layered construction for deformable animated characters

Head impacts in animal and human cadaver tests and in aircraft accidents were simulated using finite element brain models. Brain injury severity was found to correlate with peak intracranial pressure, with serious and fatal injuries occuring when the pressures exceeded 34 psi. Using this value as the maximum allowable brain stress, tolerance curves are presented for frontal and occipital impacts which represent four head accleration pulse shapes and impact durations between 1 and 10 msec. The brain pressure tolerance (BPT) curves are compared with other head injury criteria: Wayne State tolerance (WST) curve; Vienna Inst. of Tech. model; Hwy. Safety Res. Inst. maximum strain criterion (MSC); the Gadd Severity Index (GSI) and a modified version, Head Injury Criterion (HIC); and Federal Motor Vehicle Safety Standard 218. While the BPT curves are based entirely on brain injury data associated with impact, the WST, Vienna model, and MSC all use skull brain injury, and the GSI and HCI are based primarily on whole body accelerations usually greater than 20 msec. Protection based on these other indices would be inadequate for short duration (less than 3 msec.) impacts (such as when the head strikes an ineffectively padded or unpadded rigid surface). Ideally, tolerance curves for each kind of head injury should be superimposed, and the lowest curves used to define an overall head injury tolerance.

Intracranial pressure: a brain injury criterion

The biomechanics of maxillofacial trauma.

Facial impact response: a comparison of the Hybrid III dummy and human cadaver

To determine whether the routine use of fine-needle aspiration (FNA) cytology reduces the rate of unnecessary surgery, the surgical pathology of 54 thyroidectomy patients who had preoperative FNA was compared to the results obtained with 24 thyroidectomy patients who did not have preoperative FNA.

Twenty-nine (85.3%) of the 34 patients who had a positive FNA were confirmed by histology to have a thyroid neoplasm; in 24 patients, the neoplasm was malignant. Two of the 17 patients who had a negative FNA but underwent thyroidectomy based on other factors were found to have thyroid cancer. Only 8 (33.3%) of the 24 surgical specimens of patients who did not have an FNA were found to be malignant. FNA had a sensitivity of 93.5% and a specificity of 75.0%.

The results indicate that the routine use of FNA for patients with thyroid nodules reduces the incidence of unnecessary surgery. Furthermore, FNA alone is sufficient to identify most patients at risk and is, therefore, cost-effective. However, the presence of other findings suspicious of malignancy should preclude clinical decision making based on FNA alone.

Alan M. Nahum

Papers

Intracranial Pressure Dynamics During Head Impact

Intracranial pressure: a brain injury criterion

The biomechanics of maxillofacial trauma.

Facial impact response: a comparison of the Hybrid III dummy and human cadaver

Surgical management of the thyroid nodule: Patient selection based on the results of fine‐needle aspiration cytology