Prevalence of severe traumatic brain injury
In this study, the prevalence of severe traumatic head injury was high and this could have been due to the increased urbanization, limited imposed traffic laws, increased traffic volume within the country and most importantly since MRRH is the only referral center for neurosurgical conditions in Southwestern Uganda with a wide catchment area hence the high prevalence. Compared to other studies, in Tanzania and Malawi where the prevalence of STBI was slightly low at 33% (7,8) while in Switzerland, the prevalence of STBI was high at 44%(10).
The differences in the study findings may be due to differences in the study period, study design, study site and sensitization of the public on safety measures to prevent occurrences of STBI. Our study findings were different from the study conducted at MRRH except for the length of hospital stay, which was relatively comparable. The difference could have been due to the study duration and study age group (5)
Glasgow Outcome Scale Scores at discharge
In our study, we found a slightly high number of patients with GOS scores 5 followed by GOS score1, GOS score 4 and finally, GOS score 3 at discharge comparable to a study in Greece with a relatively high number of patients with GOS score 5 followed by GOS score 1, GOS score 4, GOS score 3 and GOS score 2  and slightly contrasted with a study on France with the global disability remaining high because of lack of rehabilitation center and follow up (15) and due to high frequency of multiple injuries and late presentation to the hospital(16). Hence, higher mortality from STBI was observed in the study probably attributed to age, the severity of the injury, inadequate resuscitation resources, inaccessible diagnostic equipment especially CT scan.
Factors associated with GOS Scores at discharge
Our study found that female gender had a comparable odd of unfavorable outcome at discharge as a male gender with no level of significance. Though males were the most affected, and the majority being motorcyclists which is an occupation done mostly by men, therefore, making them prone to STBI hence global disability and unfavorable outcome which is similar to other studies conducted in Tanzania, Malawi and Switzerland (7,8,17).
In this study, younger patients (age group 18–35 years) had a higher odds of unfavorable outcome compared to patients > 35 years and most likely due to the severity of the injury or cause of the injury because in this age group (18–35 years), it comprised of individuals who are very active, energetic and are most likely to take on risky works such as motorcycling (Boda riding), being involved in physical fights which made them susceptible to STBI. Though there was no significant association (p > 0.05) of the age groups with GOS score, it is biologically known that the outcome of STBI is influenced by age. However, our mean age was comparable with other studies done for example in a study done in Tanzania and Malawi with mean age 32 ± 20.1 years and 28 ± 16.3 years (7,8)
The most common cause of STBI was RTA, followed by assaults and lastly falls. However, fall had higher odds of unfavorable outcome compared to assault and RTA. This higher odd could have been due to the age disparity (common in the elderly) with reduced physiological reserves that predisposes them to a poor outcome. RTA as the common cause of injury could have been due to increased urbanization and traffic volume within Uganda in conjunction with limited imposed traffic laws (4). Several studies found similar results that the most common cause of STBI was RTA ranging from 60.7%-65.2%. Therefore, our study finding was comparable to these studies (4,7,15).
Patients who arrived in the hospital > 24hours had higher odds of unfavorable outcome compared to < 24hours and the delay in the time of arrival after injury was most likely due to long-distance, inadequate transport means, limited financial resources and absence of paramedic pre-hospital care services at the scene of injuries. In our study, the time between injury and hospital arrival was not significantly associated with GOS score at discharge. However, critical to note that time between injury and hospital arrival influences the outcome of STBI (Acosta). In a trauma center, majority of deaths occurred within 24 hours of the injury and relatively high number of patients with STBI were admitted to hospital on the day of injury, which contrasted with our study (7,11).
Pupil size and the response had a progressive increase in the odds ratios of unfavorable outcome with patients who had both pupils dilated and non-reactive having the highest odd and significant association with unfavorable outcome. This may have been as a result of very severe injury with predetermined poor outcome as with other studies, abnormal pupil size and response were correlated with poor outcome in STBI patients (13).
Surgery when indicated, in patients with STBI was significantly associated with favorable outcome and lesser odd of unfavorable outcome. This relieves increased intracranial pressure caused by intracranial space-occupying lesions, thus improving cerebral blood flow and mitigating secondary injuries. Hence, favourable outcome. However, in this study, majority of the patients did not have surgery done and this could have been as a result of lack of diagnostic CT-Scan result, conservatively manageable injury, Unsalvageable condition and/or inadequate resuscitation equipment post-surgery. Craniotomy was the commonest surgical procedure, this was comparable to another surgical centre (7).
Patients who had seizure prophylaxis were at much lesser odds of having unfavorable outcome with a significant association to favorable outcome compared to the patients who did not have seizure prophylaxis (OR = 0.31, CI; 0.097–1.001, p = 0.050). This could have influenced the manifestation of seizures, which is associated with risks of hypoxia, aspiration pneumonitis and worsening morbidity hence predisposing to unfavorable outcome. Therefore, all patients with STBI should receive seizure prophylaxis as a standard measure.
Complication during management had a strong correlation with unfavorable outcome as portrayed by the higher odds and significant association shown above. However, some of the complications that were observed were aspiration pneumonia, surgical site wound swelling and airway compromise with most commonly observed complication being aspiration pneumonia. In other studies, the common complication was airway compromise and brain edema (8,19). The disparity in the results could be related to the geographical location and management resources.