Importance of cerebral perfusion pressure management using cerebrospinal drainage in severe traumatic brain injury

Intraoperative ultrasound is valuable for detecting intracranial hematoma progression and decreasing mortality in traumatic brain injury

BACKGROUND

Our aim was to explore the clinical benefit of intraoperative ultrasound in decompressive craniectomy (DC) for traumatic brain injury (TBI).

METHODS

From January 1, 2018, through April 30, 2021, 54 patients who developed acute subdural hematoma (SDH) due to blunt injury and underwent DC with or without intraoperative ultrasound assistance were retrospectively included in our study. Logistic regression analyses were performed to compare the therapeutic efficacy in the two groups.

RESULTS

In the ultrasound group (14 patients, 25.93%), intraoperative ultrasound was used for assisting hematoma removal and/or ventriculostomy during DC. In the control group (40 patients, 74.07%), ultrasound was not used during the operation and ventriculostomy was not performed. No statistically significant differences in age, sex, initial Glasgow Coma Scale (GCS) score, blood loss, postoperative intracranial pressure (ICP), duration of hyperosmolar therapy, or Glasgow Outcome Scale Extended (GOS-E) score 6 months after injury were observed. No mortality was recorded in the ultrasound group. The mortality rate in the control group during hospitalization was 25% (p < 0.05).

CONCLUSIONS

Intraoperative ultrasound is helpful for intracranial hematoma removal and ventriculostomy with cerebrospinal fluid drainage and decreases mortality in experienced hands. The reason for higher mortality rate in the control group might result from poor hematoma clearance rate and poor postoperative intracranial pressure control. It is a useful tool for diagnosing and assisting with treatment in cases of TBI.

Optimal Timing of External Ventricular Drainage after Severe Traumatic Brain Injury: A Systematic Review

External ventricular drainage (EVD) may be used for therapeutic cerebrospinal fluid (CSF) drainage to control intracranial pressure (ICP) after traumatic brain injury (TBI). However, there is currently uncertainty regarding the optimal timing for EVD insertion. This study aims to compare patient outcomes for patients with early and late EVD insertion. Following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, MEDLINE/EMBASE/Scopus/Web of Science/Cochrane Central Register of Controlled Trials were searched for published literature involving at least 10 severe TBI (sTBI) patients from their inception date to December 2019. Outcomes assessed were mortality, functional outcome, ICP control, length of stay, therapy intensity level, and complications. Twenty-one studies comprising 4542 sTBI patients with an EVD were included; 19 of the studies included patients with an early EVD, and two studies had late EVD placements. The limited number of studies, small sample sizes, imbalance in baseline characteristics between the groups and poor methodological quality have limited the scope of our analysis. We present the descriptive statistics highlighting the current conflicting data and the overall lack of reliable research into the optimal timing of EVD. There is a clear need for high quality comparisons of early vs. late EVD insertion on patient outcomes in sTBI.

Cerebral Edema in Traumatic Brain Injury: a Historical Framework for Current Therapy

PURPOSE OF REVIEW

The purposes of this narrative review are to (1) summarize a contemporary view of cerebral edema pathophysiology, (2) present a synopsis of current management strategies in the context of their historical roots (many of which date back multiple centuries), and (3) discuss contributions of key molecular pathways to overlapping edema endophenotypes. This may facilitate identification of important therapeutic targets.

RECENT FINDINGS

Cerebral edema and resultant intracranial hypertension are major contributors to morbidity and mortality following traumatic brain injury. Although Starling forces are physical drivers of edema based on differences in intravascular vs extracellular hydrostatic and oncotic pressures, the molecular pathophysiology underlying cerebral edema is complex and remains incompletely understood. Current management protocols are guided by intracranial pressure measurements, an imperfect proxy for cerebral edema. These include decompressive craniectomy, external ventricular drainage, hyperosmolar therapy, hypothermia, and sedation. Results of contemporary clinical trials assessing these treatments are summarized, with an emphasis on the gap between intermediate measures of edema and meaningful clinical outcomes. This is followed by a brief statement summarizing the most recent guidelines from the Brain Trauma Foundation (4th edition). While many molecular mechanisms and networks contributing to cerebral edema after TBI are still being elucidated, we highlight some promising molecular mechanism-based targets based on recent research including SUR1-TRPM4, NKCC1, AQP4, and AVP1.

SUMMARY

This review outlines the origins of our understanding of cerebral edema, chronicles the history behind many current treatment approaches, and discusses promising molecular mechanism-based targeted treatments.

The Evolution of the Role of External Ventricular Drainage in Traumatic Brain Injury

External ventricular drains (EVDs) are commonly used in neurosurgery in different conditions but frequently in the management of traumatic brain injury (TBI) to monitor and/or control intracranial pressure (ICP) by diverting cerebrospinal fluid (CSF). Their clinical effectiveness, when used as a therapeutic ICP-lowering procedure in contemporary practice, remains unclear. No consensus has been reached regarding the drainage strategy and optimal timing of insertion. We review the literature on EVDs in the setting of TBI, discussing its clinical indications, surgical technique, complications, clinical outcomes, and economic considerations.

Effect of Cerebrospinal Fluid Drainage on Brain Tissue Oxygenation in Traumatic Brain Injury

The effectiveness of cerebrospinal fluid (CSF) drainage in lowering high intracranial pressure (ICP) is well established in severe traumatic brain injury (TBI). Recently, however, the use of external ventricular drains (EVDs) and ICP monitors in TBI has come under question. The aim of this retrospective study was to investigate the effect of CSF drainage on brain tissue oxygenation (PbtO₂). Using a multi-modality monitoring system, we continuously monitored PbtO₂ and parenchymal ICP during CSF drainage events via a ventriculostomy in 40 patients with severe TBI. Measurements were time-locked continuous recordings on a Component Neuromonitoring System in a neuroscience intensive care unit. We further selected for therapeutic CSF drainage events initiated at ICP values above 25 mm Hg and analyzed the 4-min periods before and after drainage for the physiologic variables ICP, cerebral perfusion pressure (CPP), and PbtO₂. We retrospectively identified 204 CSF drainage events for ICP EVD-opening values greater than 25 mm Hg in 23 patients. During the 4 min of opened EVD, ICP decreased by 5.7 ± 0.6 mm Hg, CPP increased by 4.1 ± 1.2 mm Hg, and PbtO₂ increased by 1.15 ± 0.26 mm Hg. ICP, CPP, and PbtO₂ all improved with CSF drainage at ICP EVD-opening values above 25 mm Hg. Although the average PbtO₂ changes were small, a clinically significant change in PbtO₂ of 5 mm Hg or greater occurred in 12% of CSF drainage events, which was correlated with larger decreases in ICP, displaying a complex relationship between ICP and PbtO₂ that warrants further studies.

Cisternostomy: Replacing the age old decompressive hemicraniectomy?

BACKROUND

Practical scenario in trauma neurosurgery comes with multiple challenges and limitations. It accounts for the maximum mortality in neurosurgery and yet the developing countries are still ill-equipped even for an emergency set-up for primary management of traumatic brain injuries. The evolution of modern neurosurgical techniques in traumatic brain injury has been ongoing for the last two centuries. However, it has always been a challenge to obtain a satisfactory clinical outcome, especially those following severe traumatic brain injuries. Other than the well-established procedures such as decompressive hemicraniectomy and those for acute and or chronic subdural hematomas and depressed skull fractures, contusions etcetera newer avenues for development of surgical techniques where indicated have been minimal. We are advocating a replacement for decompressive hemicranictomy, which would have the same indications as decompressive hemicraniectomy. The results of this procedure has been compared with the results of decompressive hemicraniectomy done in our institution and elsewhere and has been proven beyond doubts to be superior to decompressive hemicraniectomy. This procedure is elegant and can replace decompressive hemicraniectomy because of low morbidity and mortality. However, there is a steep learning curve and the microscope has to be used.

MATERIALS AND METHODS

Based on the clinical experience and observation of acute neurosurgical service in tertiary medical centers in a developing country, the procedure of cisternostomy in the management of trauma neurosurgery have been elucidated in the current study. The study proposes to apply the principles of microvascular surgery and skull base surgery in selected cases of severe traumatic brain injuries, thus replacing decompressive hemicraniectomy as the primary modality of treatment for indicated cases.

CONCLUSION

Extensive opening of cisterns making use of skull base techniques to approach them in a swollen brain is a better option to decompressive hemicraniectomy for the same indications.

Endovascular approach to acute aortic trauma

Traumatic thoracic aortic injury remains a major cause of death following motor vehicle accidents. Endovascular approaches have begun to supersede open repair, offering the hope of reduced morbidity and mortality. The available endovascular technology is associated with specific anatomic considerations and complications. This paper will review the current status of endovascular management of traumatic thoracic aortic injuries.

Current management of traumatic rupture of the descending thoracic aorta

Traumatic rupture of the descending thoracic aorta remains a leading cause of death following major blunt trauma. Management has evolved from uniformly performing emergent open repair with clamp and sew technique to include open repair with mechanical circulatory support, medical management and most recently, endovascular repair. This latter approach appears, in the short term, to be associated with perhaps better outcome, but long term data is still accruing. While an attractive option, there are specific anatomic and physiologic factors to be considered in each individual case.

The Endovascular Approach to Acute Aortic Trauma

Endovascular repair of the traumatically injured thoracic aorta has emerged as an exceptionally promising modality that is typically quicker than open repair, with a reduced risk of paralysis. There are a specific set of anatomic criteria that need to be applied, which can be rapidly assessed by the CT angiogram. The enthusiasm for endovascular repair must be tempered by recognition of the complications and lack of long-term follow-up, particularly in younger patients. Surgeons who are skilled in open aortic repair must not only be involved, but should take on a leadership role during the planning, deployment, and follow-up of these patients. Familiarity with all of the available devices expands treatment options. As more specific devices become available, and more follow-up is accrued, the role of endovascular stents will continue to grow.