The Relationship Between Hematoma and Pachymeninges in an Interdural Hematoma: Diagnosis and Surgical Strategy

The interdural hematoma: A subtype of convexity subdural/dural hematoma with specific radioanatomical characteristics

Background

Rare cases of biconvex hematomas splitting the convexity dura mater were reported and denominated interdural hematoma (IDH). Due to their rarity, little is known about their radiological characteristics, and in most cases, their invasive management with craniotomy and dural membrane excision is unnecessary.

Case Description

We report here a case of single burr-hole endoscopic evacuation of an IDH and its complete resolution after the 6-month follow-up imaging. The literature review reveals 11 reported cases of IDH. Most of them are male and the mean age is 65 years (range 51-90). Most of the reported IDHs were misdiagnosed as epidural hematoma or meningioma, and therefore, they have been managed invasively through craniotomy with dural excision. Diagnosis of the interdural nature was confirmed macroscopically during surgery in all cases and histology was reported for 6 cases. Image analysis found a double dural beak sign and biconvex shape on coronal planes, subarachnoid space enlargement at the collection extremities, and irregular thick inner wall as common radiological aspects of the IDH.

Conclusion

IDH is a rarely reported and often misdiagnosed dural hematoma subtype. Its invasive treatment through craniotomy is likely related to its unknown radiological characteristics. We review and raise awareness about potentially unique radiological anatomy that could avoid unnecessary invasive treatment. Moreover, we report the first case of endoscopically evacuated IDH with long-term follow-up imaging showing complete resolution.

Traumatic Epidural and Subdural Hematoma: Epidemiology, Outcome, and Dating

Epidural hematomas (EDHs) and subdural hematomas (SDHs), or so-called extra-axial bleedings, are common clinical entities after a traumatic brain injury (TBI). A forensic pathologist often analyzes cases of traumatic EDHs or SDHs due to road accidents, suicides, homicides, assaults, domestic or on-the-job accidents, and even in a medical responsibility scenario. The aim of this review is to give an overview of the published data in the medical literature, useful to forensic pathologists. We mainly focused on the data from the last 15 years, and considered the most updated protocols and diagnostic-therapeutic tools. This study reviews the epidemiology, outcome, and dating of extra-axial hematomas in the adult population; studies on the controversial interdural hematoma are also included.

Traumatic acute convexity interdural hematoma: a case report and literature review

Introduction: Interdural hematoma (IDH) is an extremely rare hemorrhage between the outer periosteal dura mater and the inner meningeal dura mater. There are 8 cases of convexity IDH reported previously but none of them were acute post traumatic one. We report the case of a patient with an initial diagnosis of acute epidural hematoma (EDH) that was eventually revealed to be an acute convexity IDH.Case report: A 57-year-old man presented to the emergency department with a complaint of falling from 2 meters. Imaging findings revealed an expanding intracranial hematoma with a linear skull fracture extending to sagittal suture, which was mistaken as an EDH. Emergent surgical evacuation was performed; the hematoma was lodged between two dural layers.Discussion: This is the first case of acute convexity IDH following trauma that has been reported. In chronic and sub-acute hematomas MRI scans could be very useful, but in acute cases under emergent circumstances, CT scan cannot make a proper differentiation between an EDH and IDH. IDH should be considered during craniotomy when extradural findings do not explain the CT scan findings. This case showed a linear skull fracture expanding to the sagittal suture, and this can be a possible explanation for IDH formation. Surgical evacuation of the hematoma without inner nor outer layer resection and leaving the outer layer open, to connect the interdural space to epidural space was first described in this report.