Key-words:
Elevated skull fracture - head injury - skull fracture
Introduction
Elevated skull fractures (ESFs) are rare compound skull fractures in which the fractured
segment is elevated above the level of the remaining skull topography. Most of the
standard medical literature describes the classification of skull fractures as linear,
comminuted, or depressed [[1]] and does not include ESFs. ESFs may be caused due to injuries by a sharp, heavy
object, or rotation of the head while hitting the object and is not restricted to
any particular type/mode of injury. It is highly underreported, and definite protocols
to guide its management are not yet in place. In recent years, these fractures have
drawn increased interest of neurosurgeons. We present a series of seventeen cases
treated during 2012–2017 in the Department of Neurosurgery, Rajendra Institute of
Medical Sciences (RIMS), Ranchi. The study is performed to analyze the presence of
any specific pattern in the etiology, epidemiologic, or clinico-radiological profile.
Patients and Methods
This is a retrospective study. All the patients admitted in the Department of Neurosurgery
at RIMS, Ranchi, between January 2012 and April 2017 were considered and all patients
confirmed to be cases of ESFs by plain computed tomography (CT) scans were included
in the study. There were no exclusions. Patient's age, gender, mode of injury, extent
of injury, Glasgow coma scale (GCS) score at admission, clinico-radiological findings,
and treatment modalities opted were noted. Postoperative complications such as seizures,
neurological deficits, cerebrospinal fluid leak, meningitis, bone flap osteomyelitis,
and infection at surgical site, etc., were looked for in all patient records. All
patients had received antibiotics and antiepileptic drugs. Patients were followed
up for at least 6 months after the event.
Results
Seventeen patients in a mixed population of adults (n = 10) and children (n = 7) with
elevated skull fractures were included in the study. All of our patients were males.
At the time of presentation, three patients had severe head injury with GCS ≤8, four
had moderate head injury (GCS >8 but ≤12), and 10 patients had mild head injury (GCS
>12 and ≤15).
The major cause of injury among adult age group was road traffic accidents (RTAs)
(n = 8). Among the pediatric age group, the major cause of injury was fall from height
(n = 4) and assault (n = 2).
The most common location of fracture was frontal (n = 8). Other locations for the
fracture were temporoparietal (n = 3), parietal (n = 3), frontotemporal (n = 2), and
frontoparietal (n = 1) [[Figure 1]]. EDH underlying elevated bone segment was seen in five patients while contusion
was seen in six patients and one later developed abscess [[Figure 2]]. Most vulnerable age group was 21–40 years (n = 8) followed by 0–20 years (n =
7) and 41–60 years (n = 2) [[Figure 3]]. Mainstay of treatment included depression or excision of elevated fragment and
titanium mesh cranioplasty.
Figure 1: The most common site of elevated skull fractures
Figure 2: The most common associations of elevated skull fractures
Figure 3: The most vulnerable age groups affected by elevated skull fractures
Discussion
Fracture of skull bones following trauma is a common finding. In neurosurgical practice,
we come across depressed fractures quite often. In some cases, however, the bone fragment
is elevated above the intact skull bone; this type of fracture is known as elevated
skull fracture. It was described as early as 1650-1550 BC in the renowned surgical
treatise “the Edwin Smith surgical papyrus.” This fracture remained unreported in
surgical texts till 1976 when Ralston mentioned its occurrence and reviewed the pathology.[[2]] Elevated fractures are still rare and underreported. The mode of injury causing
elevation of intact skull bones may include the injury made by a sharp heavy objects
or weapons which elevate the skull fracture by its lateral pull, elevation of free
segment while retrieving the weapon, tangential force acting on the intact calvarium
in association with rotation of head. The amount of force transmitted to the brain
and its overlying structures is more when applied perpendicular to the brain's surface
than tangentially.[[3]],[[4]],[[5]] Thus, injury to brain and associated structures may be less severe in elevated
fracture having tangential impact compared to depressed fractures having a perpendicular
impact.
ESFs are less contaminated than depressed fractures of the skull because the tangential
direction of force tends to drive less dirt in the wound than the perpendicular force,
thus decreasing the chances of associated infection. Factors affecting the good outcome
are amount of contamination, presence or absence of dural breach, trauma-surgery time
gap, quality of wound debridement, and appropriate and timely antibiotic and antiepileptic
medication.[[6]] A secondary insult from hypoxia, fluid and electrolyte disturbances, fever, and
seizures requires special care.
In our series, the mode of injury in pediatric age group was fall from height (including
fall in well, fall from tree and roof) in four patients, assault by sharp weapon (sword)
in two patients, and RTA in one patient. Tangential force acting on the intact calvarium
in association with rotation of head seems to be the probable mechanism in five cases
and lateral pull of weapon while retrieving it was the mechanism of injury in two
pediatric cases. The mode of injury in the adult age group was RTA in eight patients
and injury by a sharp, heavy object in two patients. In total, nine patients in our
series were involved in RTA which accounts for more than half of the patients. On
investigation, we found seven patients were not wearing helmets at the time of accident.
ESFs are found commonly in patients not wearing helmets. The patients wearing helmet
mostly got injured in the frontal area. In our series, all patients were males and
cause of injury was assault by sword, RTA, fall from height which depicts the involvement
of males more than females in outdoor activities, especially in rural areas of developing
countries like India. CT scan of head is the investigation of choice in all age groups
of ESF [[Figure 4]]. ESFs are rare and may present in a myriad of forms. Often, isolated elevated fractures
without any underlying extradural bleed and which does not leave any cosmetic defect
are managed nonsurgically. The decision of surgical intervention also depends on whether
the elevation is of full thickness of skull or involving the outer table only. If
the inner table is in line with the contour of the skull despite outer table being
massively disrupted, no surgical intervention may be needed except for cosmetic reasons.
However, a fracture which is concomitantly elevated and depressed at opposite ends
or which has underlying extradural bleed or is applying pressure on the dura may be
operated on other than for cosmetic defects alone.
Figure 4: Computed tomography scans (brain and bone window) showing elevated skull fractures.
(a) Brain window right and bone window left showing right frontal elevated skull fractures.
(b) Brain window on the right showing left frontal elevated skull fractures with underlying
contusion, bone window on the left
Surgery typically involves excising the part of the elevated fragment that is extruding
the general topography of the surrounding area of the skull. In a concomitant depressed
cum elevated skull fracture or in case there is underlying EDH, the bone fragment
is freed from the rest of the skull (bleed evacuated if present) and bone repositioned.
Grossly contaminated bone fragments should generally be removed. Proper aseptic wash
and dural closure are of utmost importance. Rarely, elevated fragment is excised,
and titanium mesh cranioplasty is done either in the same sitting or interval cranioplasty
may be done. Occasionally, the elevated fragment may leave the skull like part of
the jigsaw puzzle and may reposition itself leaving only little cosmetic defect. Similar
rare case of jigsaw depressed fracture has been reported.[[7]]
Conclusion
ESFs constitute uncharacteristic neurosurgical emergencies, associated with head injuries
due to RTA, assault, fall from height, and various other forms of trauma. It is easily
detectable by CT scan and requires prompt treatment. Although a rare entity, the evidence
of scarcity of these cases should not be taken as an excuse to not include them in
the classification of skull fractures. We encountered 17 such cases at our institute
in over 5 years and this clearly obviates the necessity of discussion of these cases
in world medical literature and towing of attention of neurosurgeons in defining an
objective protocol for the management of ESF. Definite protocol and appropriate management
of this type of skull fracture will prevent unnecessary morbidity and mortality. Reporting
of all such cases should be done so that the variety of cases of this entity may be
seen in world medical literature.
