Contrecoup Extradural Hematoma: When Hematomas Do Not Follow Rules.

Extradural hematoma (EDH) is a fairly common entity in neurosurgical practice but EDHt at a contrecoup site and crossing a cranial suture is rare. The authors present a case of EDH due to contrecoup injury in whom sutural diastases was noted and hematoma was seen to be crossing the adjacent suture. This was accompanied with subdural hematoma (SDH) at the coup site. According to the best of our knowledge, it makes the case only the 13th such to be reported in adults. A 27-year-old male patient was brought by relatives with a history of fall from a height resulting in head trauma over the left posterior parietal region. The patient presented with headache at the site of impact. Computed tomography (CT) scan of the brain revealed an undisplaced fracture of parietal bone on the left side (coup site) along with a small concavo-convex hyperdense lesion suggestive of a SDH. Scan also revealed a large biconvex, hyperdense lesion in the right frontoparietal region (contrecoup site). The hematoma was seen to be evidently crossing the coronal suture. Sutural diastases of coronal suture was suspected and the same was noticed intraoperatively. Approximately 80cc of clot was removed and hemostasis was achieved through coagulation of the middle meningeal artery and via dural hitch sutures. Contrecoup EDH across the adjacent suture with sutural diastases is rare as it does not follow the set rules of hematomas. A high index of suspicion is central in arriving at a rapid diagnosis and an early surgery to achieve a favorable outcome. The authors recommend a CT scan along all three planes along with a three-dimensional reconstruction for ready diagnosis. Contrecoup EDH with sutural diastases is a distinct and potentially dangerous entity and neurosurgeons should be aware of the same. Copyright:

INTRODUCTION

Extradural hematoma (EDH) is a collection of blood between the dura mater and inner table of the skull and is a fairly common entity in neurosurgical practice. It generally occurs due to injury at the site of impact (coup injury)[1] and contrecoup injury-causing EDH is rare with only 12 cases having been reported in the literature so far.[2] We present a case of EDH due to contrecoup injury in whom sutural diastases was noted and hematoma was seen to be crossing the adjacent suture which makes the case even rarer.

CASE REPORT

A 27-year-old male patient, a driver by profession, was brought by relatives with a history of fall fro]m a height 4 h before admission resulting in head trauma over the posterior left parietal region. The patient had a transient loss of consciousness before the presentation and had two episodes of vomiting. No signs of external injury were present on the scalp. The patient was hemodynamically stable and his plain computed tomography (CT) scan of the brain revealed an undisplaced fracture of parietal bone on the left side at the coup site along with a small concavo-convex hyperdense lesion suggestive of a subdural hematoma (SDH). Scan also revealed a large biconvex, hyperdense lesion in the right frontoparietal region, at the contrecoup site. The hematoma was seen to be evidently crossing the coronal suture. Without any further delay, the patient was taken up for emergency craniotomy and evacuation of clot. A right-sided reverse question mark incision was made exposing the right frontotemporoparietal area keeping in mind the CT findings. Sutural diastases of coronal suture was suspected and the same was noticed intraoperatively. Approximately 80cc of clot was removed, and hemostasis was achieved through coagulation of the middle meningeal artery and via dural hitch sutures. The bone flap was replaced and the wound was closed in layers after placement of an epidural suction drain.

The patient had an uneventful postoperative course with full neurological recovery and was discharged on the 5th postoperative day. Postoperative CT scan revealed complete evacuation of EDH and showed no expansion of SDH at the coup site [Figure 1].

Figure 1

(a) Plain computed tomography brain, axial view showing right-sided frontal biconvex hyperdense lesion at the contrecoup site and a left parietal concavo-convex hyperdense lesion at the coup site. (b) Plain computed tomography brain, bone window, axial view showing left parietal bone fracture at coup site and biconvex hyperdense lesion in the right frontal region which is crossing the coronal suture. (c) Intraoperative photograph showing coronal suture diastases. (d) Intraoperative photograph showing hematoma spreading across the coronal suture (indicated by black arrow)

DISCUSSION

EDH is a commonly encountered neurosurgical emergency and all neurosurgeons are very well versed with this entity. It is a commonly accepted theory that these hematomas occur at the coup site and are associated with fractures of skull.[1] Occurrence of these hematomas at the contrecoup site is very rare with only 12 other cases reported in the literature.[2] This makes the case only the 13th such and thus extremely rare and reportable as the literature is deficient in the same.

Takeuchi et al.[3] reported maximum incidence of EDH at the frontal location and in females, but both findings do not corroborate with our case report.

Possible mechanism

EDH due to coup injury is due to directly transmitted energy which results in EDH formation either due to deformity of less elastic skull or fracture at the coup site which may strip off the dura from the inner calvarium.[4] Nath et al. stated that due to the bouncy force of cerebrospinal fluid and brain's elastic property, the brain bounces many times both in coup and contrecoup sites to come into normal position and during this process, it creates different negative pressure zones which lead to the formation of acute SDH commonly and EDH rarely.[2] It was proposed that EDH can occur due to the buckling effect of skull exactly opposite to the site of impact[5] or due to the mechanism of cavitation effect and inertial loading.[4]

The proposed theories for contrecoup head injury do not adequately address the formation of EDH at this site, and thus, detailed studies are needed to prove the same beyond doubt. The authors agree to the same and they fall short of providing a mechanism for the same based on a single case report.

The widely accepted notion about EDH is that it does not cross the cranial sutures because the periosteal layer of the dura is tightly adherent to the cranial sutures and the entity is very rare in adults. However, pediatric population incidence is different, and in a study of EDH in pediatric population,[6] the authors reported a small fraction (11%) of children who had an EDH which had crossed the adjacent suture. Out of a total of 7 such patients, an adjacent skull fracture was found in four patients, which explained the extent of hematoma. Further, sutural diastases was present in two patients which is similar to the cause in our patient. Although this study limited itself to pediatric population and included hematomas at only coup site, it does consolidate the idea that sutural diastases may result in EDH formation across the adjacent suture.

Sutural diastases is a relatively small entity to be readily recognizable, especially in the absence of three-dimensional (3D) reconstructed images. This is particularly important as it may dictate the extent of craniotomy in case of spread of hematoma across the suture. The same may be given a miss considering the rapidly evolving nature of the pathology and the dire repercussions in case of a therapeutic delay. In our case, as the hematoma was evidently seen to spread across coronal suture, sutural diastases was suspected and the craniotomy was planned across the coronal suture to start with. This may not be the case always and many times and across many institutions, especially in developing countries, only the axial sections of CT brain are done as a part of a quick radiology survey and it is likely that surgeons might turn a blind eye to the same considering its small size. This view was seconded by Sahoo et al.[2] who concluded that detection of sutural diastases may not be possible at normal axial views. The authors thus recommend a CT scan image reconstruction across all three planes alongside 3D reconstruct if possible which not only aids in quick recognition but also has an impact on therapeutic consequence. This process is becoming less time consuming due to the advent of faster and better CT machines and consoles and should be stressed upon for especially in patients with a high index of suspicion.

This case is rare because it disobeyed all three generic rules of hematoma, namely

Formation of EDH at contrecoup site

Formation of SDH at coup site

Spread of EDH across cranial suture

CONCLUSION

Contrecoup EDH across the adjacent suture with sutural diastases is rare as it disobeys the generic rules of hematoma. High index of suspicion along with prompt action is central in arriving at a rapid diagnosis so as to plan an adequate-sized craniotomy across the suture to achieve a favorable outcome. In the ever-evolving scenario of radiodiagnostic equipment, it is hardly time consuming to get a global view of pathology via a CT scan along all three planes along with a 3D reconstruction and the authors strongly recommend the same. Contrecoup EDH with sutural diastases is a distinct and potentially dangerous entity and neurosurgeons should be aware of the same as “being forewarned is being forearmed.”

Written and informed consent was obtained from the patient for publication.

All sources of financial and material support including the following: NA

Any portion of the contents of the paper may have not been presented or published previously.

Limitations of the study:

Small sample size

Not a multicentric study

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Research quality and ethics statement

The authors followed applicable EQUATOR Network (http://www.equator-network.org/) guidelines, notably the CARE guideline, during the conduct of this report.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.