Keywords
depressed fracture - split graft - calvarium - CSF leak - repair
Introduction
Frontal bone fracture often involves the frontal sinus, comprising around 5% of all
maxillofacial injuries.[1] Their location and proximity to vital structures such as orbit and intracranial
contents make these fractures an essential entity for management. Depressed fracture
in this region is often the result of high-energy blunt traumatic impact. Depressed
fracture is often classified into open and closed based on the integrity of the overlying
scalp. Comminuted fractures are fractures in which bone is broken in at least two or more places and are often
the result of high-impact traumas. Open depressed fracture often requires surgical
management. Closed fracture with depth of fracture segment below the inner table requires
surgical management. The standard teaching is to elevate the depressed fracture or
implant cranioplasty in case of comminuted fracture. In this article, we present a
close comminuted frontal depressed fracture involving the outer and inner table of
the frontal sinus that underwent repair using a split cranial graft taken from the
posterior margin of the frontal bone. It is a novel technique that does not require
the placement of a foreign material like titanium mesh to replace the comminuted fracture
segment, thus decreasing the risk of infection. Also, in a developing country like
the Indian subcontinent, it is a cost-effective method.
Case Description
A 43-year-old gentleman presented to our center with a history of road traffic accident,
a two-wheeler rider collision with another two-wheeler, following which he was unconscious
for approximately 30 minutes, and there was a history of nasal bleeding. There was
no calvarial defect; however, his skin over the frontal bone was necrosed ([Fig. 1]). He was evaluated with a computed tomography (CT) scan of the head, which showed
a comminuted frontal depressed fracture involving both the outer and inner tables
of the frontal sinus ([Fig. 2]). There was no parenchymal injury to the brain on the CT scan. He was evaluated
with CT cisternography, given doubtful cerebrospinal fluid (CSF) rhinorrhea; however,
no defect was noted. Since the depressed fracture segment was extending below the
inner table of the calvarium, the patient was planned for surgical management. We
planned the patient for the elevation of the frontal depressed fracture and reconstruction
at the same sitting using a split calvarial graft taken from the posterior margin
of the frontal bone. The necrosed skin over the forehead was excised, and a partial-thickness
skin graft was performed with the help of a plastic surgery team. During the postoperative
period, the patient recovered well and did not develop any fresh complaints. The postoperative
CT scan of the head showed good calvarial defect repair without any obvious disfigurement
([Fig. 3]).
Fig. 1 A preoperative clinical photograph of the patient showing necrosed skin over the
forehead with significant skin blackish discoloration.
Fig. 2 (A, B) The radiology of the patient shows a preoperative noncontrast computed tomography
(NCCT) of the brain (both parenchymal and bone window), depicting the frontal depressed
fracture with involvement of both outer and inner table of frontal sinus along with
hemosinus. There was no pneumocephalus or associated intracranial injury. (C) Three-dimensional formatted CT images of the head showing frontal comminuted depressed
fracture.
Fig. 3 The intraoperative image noticed after elevating the myocutaneous flap. We can see
the comminuted depressed fracture of the frontal bone with multiple fragments of variable
size. The purple arrow shows the mucosa of frontal sinus bulging out after compression by the fracture fragments
of the frontal bone. The blue star marks the area of the glabella with comminuted fracture fragments. The green arrow marks the fracture line involving the supraorbital ridge.
Surgical Technique
The patient was positioned supine with slight extension. First, our plastic surgery
colleague debrided the necrosed skin. We marked a standard bicoronal skin flap extending
from one tragus to another and curving in the midline behind the hairline. The surgical
part was painted and draped with aseptic precautions. After raising the mucocutaneous
flap, we could visualize the frontal bone, which was fractured into multiple pieces
([Fig. 4]). A bifrontal craniotomy was performed, and the fractured segments of the frontal
bone were removed. It should be noted that the craniotomy was extended posteriorly,
just anterior to the coronal suture. A larger-sized craniotomy could provide an appropriate
split calvarial graft, which will help repair the defect. The area of depressed fracture
was meticulously measured, and the craniotomy defect that appeared after removing
the fractured segments was calculated on the CT console (GE Company). After marking
the graft size on the frontal craniotomy bone flap, the split calvarial bone graft
was crafted by separating the outer table of the bone flap from the inner table using
a C-1 bit of Midas Rex high-speed drill system, chisel, and hammer ([Fig. 5]). This ensured minimal bone loss and helped design the flap of the desired shape.
This split calvarial graft was fixed using magnetic resonance imaging (MRI) compatible
titanium plates and screws ([Fig. 6]). After calvarial reconstruction, the plastic surgery team excised the necrosed
skin. The skin defect was repaired using a full-thickness graft from the right groin
region. The surgical incision was closed in layers, and a suction catheter connected
to a minivac suction container was inserted. The postoperative period was uneventful,
and the CT scan done on the second postoperative day suggested an excellent alignment
of the split calvarial graft ([Fig. 7]). The operative wound was healthy, and the sutures in the graft area were removed
after 3 weeks. The clinical photographs after 6 weeks suggest a good cosmetic appearance
and no wound-related complications ([Fig. 8]). He resumed his normal activities as a farmer and is in regular follow-up visits.
Fig. 4 (A) The intraoperative image depicts the photograph of the split calvarial graft where
the outer table is separated from the inner table (green arrow) of the posterior frontal bone flap. (B) We used a combination of drill, chisel, and hammer for fashioning and designing
the split calvarial bone graft of desired size (black star).
Fig. 5 The intraoperative image with repair of frontal depressed fracture using split calvarial
bone graft. After removal of the fractured fragments, the defect was repaired by using
the outer table (blue star), which was separated from the inner table (blue triangle) of the posterior frontal bone. The autologous graft was fixed at the anterior margin
by using nonabsorbable sutures and titanium miniplates and screws.
Fig. 6 The postoperative clinical photograph showing healthy status of the full-thickness
skin graft that was used to repair the skin defect of the forehead.
Fig. 7 (A, B) The postoperative three-dimensional formatted image showing good repair of frontal
comminuted depressed fracture using the outer table (blue star) separated from the inner table (blue circle) of the posterior frontal bone just anterior to the coronal suture. The tube of the
minivac system can be noticed traversing through the wound cavity under the scalp.
Fig. 8 The follow-up clinical photographs after 6 weeks suggest good cosmetic appearance.
The yellow arrow indicates the line of full-thickness graft uptake and the red arrows indicate the healed stitch line of bicoronal skin flap.
Discussion
The most common cause of frontal fracture is high-energy impact to the upper third
of the face, which is mainly seen in motor vehicle accidents. Other causes include
assault with blunt or penetrating objects, falls from height, industrial accidents,
and high-impact sports/contact sports injuries like martial arts and boxing injuries.[2] Our patient had a history of high-velocity two-wheeler injury. Since this region
hosts a variety of critical structures, including the frontal sinus, cribriform plate
of the ethmoid, dura, frontal lobe, orbit, globe, and facial bones, the fracture of
the frontal bone could present in many ways. Forehead laceration associated with frontal
depression is a hallmark clinical presentation. It is also commonly associated with
periorbital edema and ecchymosis. CSF leak, meningitis, and decrease in sensorium
and seizure episodes suggest parenchymal intracranial injury. Diplopia, impaired visual
acuity, and restricted ocular movements suggest injury to the orbit.[3]
[4] In our patient, there was necrosis of the skin over the forehead with a frontal
depressed fracture. There was a suspected dural defect leading to CSF rhinorrhea.
However, he was neurologically intact without any associated ophthalmological features.
The gold standard for diagnosing frontal fracture (depressed or linear/nondepressed)
is non-contrast-enhanced high-resolution computed tomography (HRCT) with thin cuts.[5]
[6] The axial section provides the presence and degree of fracture displacement. The
coronal section provides information regarding the floor of the frontal sinus and
the roof of the orbit. Sagittal reconstruction enhances visualization of nasofrontal
outflow tract (NFOT) injuries and displacement of the outer and inner frontal sinuses.
In a head CT scan, we should look for signs that suggest intracranial injury, like
pneumocephalus and coup (frontal) countercoup (occipital) contusions. Three-dimensional
reformatted images help visualize external contour deformities of the frontal bone.[7] In our patient, plain noncontrast CT (NCCT) of the brain showed a comminuted frontal
depressed fracture involving both the outer and inner tables of the frontal sinus
([Fig. 2].). There was no parenchymal injury on the CT scan. He was evaluated with CT cisternography,
given doubtful CSF rhinorrhea; however, no apparent bony defect or extravasation of
dye was noticed in the paranasal sinuses or the base of the skull.
In our patient, there was the presence of a comminuted depressed fracture with involvement
of overlying skin and frontal sinus, which made him prone to delayed CSF leak, frontal
bone osteomyelitis, meningitis, brain abscess, residual forehead contour defects,
and deformities. Since the head CT scan showed depression of the fracture segments
below the inner table of the calvarium, the patient was planned for surgical intervention
in the form of elevation of the depressed fracture and repair of the overlying skin.
The standard for depressed fracture is the elevation of the depressed segment. However,
in the cases with comminuted frontal depressed fractures, it is usually not possible
to elevate the multiple fracture segment and achieve the desired surgical and cosmetic
outlook. Removing the multiple fractured segments and repairing the defect with titanium
mesh cranioplasty is prudent in these cases. However, placing a foreign body increases
the surgery cost, and there is a theoretical risk of infection. Also, if the edges
of the titanium mesh are not fixed properly, it can erode the overlying thin skin
of the forehead. Thus, we propose a novel method of repair and reconstruction of the
frontal depressed fracture using the split calvarial graft taken from the posterior
frontal bone. The posterior frontal bone, just anterior to the coronal suture, is
thick, facilitating the splitting of the outer table from the inner table of the bone
flap. We recommend placing an outer table over the defect created by discarding the
fracture segments. The natural contour of the outer table of the frontal bone gives
a good cosmetic appearance besides the robust strength of the bone flap. The edges
of the bone flap are fixed using nonabsorbable silk sutures to provide a rigid approximation
with the craniotomy margins. Since the bone graft used is autologous, this method
greatly reduces the risk of infection. Also, it should be noted that this method is
cost-effective as we are not using an external implant like titanium mesh, as well
as plates and screws for fixation. In a developing country like India, this dramatically
reduces the surgery cost and thus can be recommended for optimal utility of resources
in emergency settings and situations with financial constraints.
Conclusion
Management of frontal depressed fractures becomes challenging because of the nature
of high-energy impact injury and its proximity to the paranasal sinuses and orbital
and intracranial structures. The conventional procedure of depressed fracture elevation
and reconstruction using mesh cranioplasty has limitations. We are proposing a novel
method of repair using split calvarial graft, which is ready for use in emergency
settings. This cost-effective method has a reduced risk of infection and imposes no
additional financial burden to the patient.
