Reversible coma and Duret hemorrhage after intracranial hypotension from remote lumbar spine surgery: case report

Duret Brainstem Hemorrhage After Transtentorial Descending Brain Herniation: A Systematic Review and Meta-Analysis

BACKGROUND

Historically, the occurrence of hemorrhage in the brainstem after an episode of supratentorial intracranial hypertension was described by Henri Duret in 1878. Nevertheless, to date the eponym Duret brainstem hemorrhage (DBH) lacks systematic evidence regarding its epidemiology, pathophysiology, clinical and radiologic presentation, and outcome.

METHODS

We conducted a systematic literature review and meta-analysis using the Medline database from inception to 2022 looking for English-language articles concerning DBH, in accordance with the PRISMA guidelines.

RESULTS

The research yielded 28 articles for 32 patients (mean age, 50 years; male/female ratio, 3:1). Of patients, 41% had head trauma causing 63% of subdural hematoma, responsible for coma in 78% and mydriasis in 69%. DBH appeared on the emergency imaging in 41% and on delayed imaging in 56%. DBH was located in the midbrain in 41% of the patients, and in the upper middle pons in 56%. DBH was caused by sudden downward displacement of the upper brainstem secondary to supratentorial intracranial hypertension (91%), intracranial hypotension (6%), or mechanical traction (3%). Such downward displacement caused the rupture of basilar artery perforators. Brainstem focal symptoms (P = 0.003) and decompressive craniectomy (P = 0.164) were potential favorable prognostic factors, whereas an age >50 years showed a trend toward a poor prognosis (P = 0.0731).

CONCLUSIONS

Unlike its historical description, DBH appears as a focal hematoma in the upper brainstem caused by the rupture of anteromedial basilar artery perforators after sudden downward displacement of the brainstem, regardless of its cause.

Imaging of Altered Mental Status

Neuroimaging is an invaluable diagnostic tool for sorting through the vast array of etiologies that underlie altered mental status (AMS). Head computed tomography (CT) without contrast is the primary modality for evaluation of AMS and should be complemented by MR imaging in cases of negative CT but high clinical concern. Studies to maximize brain imaging efficiency and improve the yield of positive scans through the utilization of clinical and laboratory pre-scan diagnostics are ongoing. However, imaging remains the gold standard due to its rapidity with which certain diagnoses can be made or excluded.

Recovery of Functional Independence After Traumatic Transtentorial Herniation With Duret Hemorrhages

Historically, Duret hemorrhages have conferred a devastating prognosis. However, recent case reports suggest that cognitive and functional recovery are possible after Duret hemorrhages. Here, we describe a patient who recovered consciousness, communication, and functional independence after Duret hemorrhages caused by traumatic transtentorial herniation. We performed prospective, standardized behavioral assessments, structural MRI scans and stimulus-based functional MRI (fMRI) scans during the first 2 years of recovery. The multimodal assessments revealed reintegration of neural networks mediating language and consciousness, concurrent with the reemergence of functional independence. These observations provide insights into network-based mechanisms of recovery from coma and add to a growing body of evidence indicating that Duret hemorrhages are not invariably associated with a poor prognosis.

Pseudohypoxic Brain Swelling After Uncomplicated Lumbar Decompression and Fusion for Spondylolisthesis

BACKGROUND

Pseudohypoxic brain swelling (PHBS), also known as postoperative intracranial hypotension-associated venous congestion, is a rare complication after neurosurgery characterized by rapid and often severe postoperative deterioration in consciousness and distinct imaging findings on brain magnetic resonance imaging. Imaging findings associated with PHBS include computed tomography and magnetic resonance imaging findings that resemble hypoxic changes and intracranial hypotensive changes in basal ganglia and thalamus, telencephalic, and infratentorial regions without notable changes in intracranial vasculature.

CASE DESCRIPTION

This report describes the case of an L4-5 microdiskectomy with posterior decompression and fusion complicated by clinical and radiographic findings resembling PHBS without a known intraoperative durotomy.

CONCLUSIONS

Spine surgeons should be alerted to the possibility that PHBS may occur in patients even after an operation without known durotomy or cerebrospinal fluid leakage and with spontaneous clinical resolution unrelated to suction drainage changes or epidural blood patches.