Risk factors of prognosis in older patients with severe brain injury after surgical intervention

Traumatic brain injury (TBI) poses a significant challenge to the healthy life of the older patients. China has more patients with TBI than most other countries [1], and severe TBIs impose a significant economic burden on society and families [2]. Despite the continuous improvement of treatment technology [3‐5], the prognosis of older patients (age ≥ 60 years) with severe brain injury remains unsatisfactory, and their mortality and disability rates continue to be high [6, 7].

There is still a lack of unified guidelines for treating older patients with TBI [8, 9]. There are significant differences in treatment management among different centers for older patients with TBI. Some studies show that the prognosis of older patients with severe TBI after surgical intervention is poor [10, 11]. In contrast, other studies emphasize that surgical intervention may positively impact treatment and improve the prognosis of patients [12, 13]. Recent research [6] has found that surgical intervention increased complications and length of hospital stay but was not associated with increased mortality in the older patients with TBI (age ≥ 80 years).

Therefore, this study evaluated the risk factors affecting the prognosis of older patients with severe TBI treated by surgery to understand the impact of surgical intervention on patients’ recovery. This will help make early decisions according to specific information and subsequently make relevant interventions to reduce the mortality of older patients with severe brain injury and improve their quality of life.

Severe head injury is a high-risk disease in the older population with a long hospital stay and high mortality, which brings great problems to clinical treatment [15‐17]. Previous studies had shown that the older the age, the worse the prognosis and the higher the hospital mortality [18‐20]. The results of this study show that the poor prognosis of older patients with severe TBI after surgical intervention gradually increased with age especially in patients aged ≥ 75 years, and the proportion of poor prognosis was > 70%. The main reason may be that the older the patient, the more serious the functional degradation and the more postoperative complications and poor prognosis will occur. Age is an independent risk factor for prognosis in older patients with severe craniocerebral injury after surgery. In clinical practice, we should reasonably evaluate the patient’s condition according to age and choose the best treatment to improve the prognosis of patients.

The functions of various organs and immunity in older adults gradually decline with age, and underlying diseases such as hypertension, diabetes, and heart disease also occur. The combination of physiological aging and pathological conditions aggravates the mortality risk of severe TBI in the older population. Compared to younger people, older people have more complications, higher mortality, and longer time for neurological recovery [21, 22]. This study found that, despite active intervention, the mortality of older patients with three or more underlying diseases was much higher than that of patients with two or fewer underlying diseases. The previous underlying disease is an independent risk factor of the prognosis in older patients with severe TBI after surgical intervention and should be considered in clinical practice.

There is no clear conclusion on whether using antiplatelet or anticoagulant drugs before injury affects the prognostic outcome of older patients with severe TBI. Previous studies have found no significant difference in the poor prognosis between TBI patients who used antiplatelet or anticoagulant drug before the injury and those who did not [23, 24]. However, other study shows that Elderly trauma patients using antiplatelet or anticoagulant drugs can lead to elevated risk of intracerebral hemorrhage and poor prognosis [25]. In this study, the use of anticoagulants before injury did not affect the prognosis, and the difference was not significant. However, we found that these patients were more likely to have incomplete intraoperative hemostasis or postoperative hemorrhage, which may increase the difficulty of treating the disease and the length of hospital stay. Therefore, perioperative management is necessary for patients who have received antiplatelet or anticoagulant drugs before the injury.

Because of different degrees of brain atrophy in older patients, the clinical symptoms such as pupil change, slow respiration, and heart rate, and increased blood pressure in the early stage of cerebral hernia are often atypical, which makes it easy to cover up the condition of older patients. For older patients with severe brain injury, when the optimal treatment period is missed, it can cause great difficulties for subsequent treatment. Therefore, early evaluation based on CT images can help predict disease severity as early as possible and facilitate early treatment and intervention. It has been pointed out in the literature [22] that CT images can indicate intracranial lesions in older patients earlier than GCS and provide earlier clinical strategies for clinical treatment. The cistern of the annulus is adjacent to the brainstem. When supratentorial lesions cause acute intracranial hypertension, the morphological changes of the annulus cistern are often the first to appear and it can be used as the early manifestation of cerebral herniation [26]. Patients with the disappearance of the cisterna ambiens after TBI tend to have a deep coma and a poor prognosis. The poor prognosis is mainly because patients with the disappearance of the cisterna ambiens often indicate diffuse intracranial hypertension and secondary brain stem injury, which can lead to deterioration of the patients [27]. Our study showed that the disappearance of cisterns was significantly associated with worse prognosis and higher mortality in older patients with severe TBI after surgical intervention. Therefore, the surgical intervention decision should be made as early as possible according to the width change of the cisterna ambiens. The reduction of the width of the cisterna ambiens represents the possibility of brain stem injury, but the extent to which the width of the cisterna ambiens is reduced as an indication for surgical intervention needs further clinical research.

Older adults are prone to desaturation of blood oxygen because of coma after severe TBI, vomit regurgitation caused by asphyxia, coupled with their cardiopulmonary insufficiency for the decline of their physical function. When older patients experience a TBI, their brain tissue is more sensitive to hypoxia than usual after injury. When the blood oxygen saturation < 90%, the brain cells are severely hypoxic, which aggravates the edema and necrosis and the patient’s condition. This study found that the mortality rate of patients with oxygen saturation < 90% was as high as 87.7%, which was much higher than that of the non-occurrence group. Studies [28] have shown that patients with severe craniocerebral injury have a high proportion of hypoxia during emergency treatment. Therefore, first aid before admission is essential. Suppose the injured older patients with coma can be found in time. In that case, the airway can be opened, and hypoxemia can be corrected before admission. It may reduce the secondary damage caused by brain cell hypoxia, saving time for further treatment. Studies have shown [29] that tracheotomy in the early stages of severe craniocerebral injury can help reduce secondary injury and adverse events in hospitals and increase the chances of early rehabilitation and discharge of patients. Therefore, to improve the airway, increase the oxygen supply of brain tissue cells, and improve the prognosis of older patients with severe brain injury, attention should be paid to airway management in the early stage, and tracheotomy or tracheal intubation should be performed as soon as possible if necessary.

For the older patients with severe TBI, craniotomy hematoma evacuation and decompressive craniectomy are the main surgical procedures [30]. In the process of decompressive craniectomy, there may be complicated by intraoperative brain swelling on the patients with cerebral herniation or high intracranial pressure. Once brain swelling occurs, the prognosis of patients is often poor [31]. This study found a mortality rate of more than 75% in cases with intraoperative brain swelling, significantly higher than in cases without brain swelling (P < 0.001). The possible causes of intraoperative brain swelling in older patients with severe brain injury are mainly due to rapid disease progression without early detection and complicated by ischemia–reperfusion injury after decompression [32]. Intraoperative brain swelling in older patients with severe brain injury is a complex pathophysiological process, and further research is needed to confirm the main factors. Thus, reducing the incidence of intraoperative brain swelling in older patients with severe brain injury is important.

Older patients have a poor prognosis with severe TBI. Although active surgical treatment is administered, with an increase in age, postoperative complications and mortality become higher, and their postoperative neurological recovery time also becomes longer. This study showed that patients aged ≥ 75 years had worse postoperative recovery than those aged < 75 years. Therefore, we should perform a reasonable evaluation based on age in clinical practice. Surgical intervention may improve prognosis and reduce mortality in older patients aged < 75 years. For older patients aged ≥ 75 years, surgical intervention may need to be carefully considered.

This study has several limitations. First, this study was retrospective in design. Second, we did not analyze the data on complications. Third, there are few data on the use of antiplatelet or anticoagulant drugs. Therefore, it may be impossible to provide a comprehensive, high-quality data basis for all questions arising from this particular topic. Therefore, further studies are needed to evaluate prognostic factors to provide better and more favorable treatment measures for older patients with severe TBI in the future.

This study clearly indicates that age, previous underlying diseases, the disappearance of ambient cistern, oxygen saturation < 90% and intraoperative brain swelling are associated with poor prognosis in older patients with severe brain injury undergoing surgical treatment. Surgical intervention may improve prognosis and reduce mortality in older patients aged < 75 years. But for older patients aged ≥ 75 years, the prognosis was poor after surgical intervention. The advantages and disadvantages of surgery should be carefully considered in older patients with severe brain injury of different ages. In clinical practice, a reasonable evaluation should be made according to age. This study further complements previous studies related to surgery in older patients with traumatic brain injury. It provides decision-making and reference for the surgical treatment of older patients with severe TBI, which can help to improve the treatment prognosis and reduce mortality in older patients with severe TBI. The number of older patients with TBI may increase with the aging of the population. Therefore, it is necessary to further study the prognostic factors after surgical treatment for severe brain injury in older adults.