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Researchers Develop SPIN Score for Estimating Survival after Penetrating Traumatic Brain Injury


Researchers have developed a new clinical risk stratification tool called the Surviving Penetrating Injury to the Brain (SPIN) scale based on an analysis of factors associated with survival from penetrating traumatic injury (pTBI). A report on the methodology for the scale was published in a paper online October 26 in Neurology.

The SPIN score, which has not yet been validated, may presently serve as "a preliminary tool that may provide guidance for physicians and families in their direction-of-care decision-making in patients with pTBI," and future external validation should expand its use, the study authors, led by Susanne Muehlschelegel, MD, MPH, critical care neurologist at UMass Memorial Medical Center, wrote.

The main cause of pTBI — gunshot wounds — is a serious public health problem, the study authors noted, adding that  mortality rates for pTBI vary widely between trauma centers. A comprehensive, multivariable score for estimating survival after pTBI is necessary to identify ways to improve patient outcomes, they said.

For their study, the researchers retrospectively analyzed data on 413 pTBI patients using local trauma registries at two level-one trauma centers in the United States: the University of Maryland Shock-Trauma Center (n=377) in an urban setting and the UMass Memorial Medical Center, n=36) in a rural area. The patients were an average age of 33 years and were predominantly male; patients who were dead upon arrival at the trauma center were excluded.

They found that 175 patients (42.4 percent) survived to hospital discharge (the researchers' primary endpoint) and six months after pTBI (the secondary endpoint); there were no additional deaths at either center between hospital discharge and six months.

Additionally, the researchers found a wide range of factors associated with likelihood of survival. These included higher scores on the motor Glasgow Coma Scale subscore and pupillary reactivity, which were the two strongest predictors of survival. Injury that was not self-inflicted transfer status from another hospital, female gender, a lower Injury Severity Score, and a lower international normalized ratio were all independently associated with survival (p<0.001).

The researchers developed the SPIN score as a sum of individual points, with greater points allocated to stronger predictors of survival. However, they did not include radiologic factors in the scale, as these would have introduced too many parameters and limited predictive power. The score ranges from four to 52; higher scores indicate a stronger likelihood of survival.​

Among their findings, 98 percent of the patients with a SPIN score of 35 and above survived, while only 3 percent of patients with a score of 20 or below survived, and no patients with a score of 16 or below survived.

The researchers noted several limitations to their study, including the lack of score validation; the retrospective nature of the study, which may have resulted in incomplete collection of some outcome variables; and that most of the study participants were from the University of Maryland Shock-Trauma Center, which potentially biased the results toward an urban pTBI population.