Keywords
neurosurgery - pediatric neurosurgery - skull fractures - depressed skull fractures
- vacuum-suction
Palavras chave
neurocirurgia - neurocirurgia pediátrica - fratura craniana - fratura em afundamento
- vácuo sucção
Introduction
Depressed skull fractures are an entity often associated with high kinetic energy
trauma, leading to misalignment of the skull bone fragments from their original position.[1]
[2] Up to 20% of the patients with skull fractures are represented by the pediatric
population, and it is noteworthy that in half of these cases, the type of injury is
characterized by a depressed fracture. In this age group, especially in young children,
this entity is associated with obstetric trauma, falls and physical injury.[3]
The treatment of depressed skull fractures is multimodal in nature, ranging from conservative
treatment, with clinical observation and expectation of spontaneous fracture reduction,
to surgical procedures to correct the bone defect.[3]
[4]
[5]
[6] The authors present a case report of the correction of a depressed skull fracture
in a pediatric patient, using the physical principles of vacuum suction, described
through the vectors applied over the skull, and its benefits.
Case Report
A newborn patient suffered a head injury during labor. She didn't evolve with any
neurological complications, but was immediately submitted to a cranial computed tomography
(CT) scan, after a skull defect was detected on physical examination ([Fig. 1]). She was diagnosed with a depressed skull fracture, being referred to a neurological
surgeon after hospital discharge. The CT scan ([Fig. 2]) shows a depressed right frontal bone fracture, with no underlying brain injuries.
Interventional treatment was indicated to avoid future complications, such as seizures,
and for cosmetic reasons. Nonsurgical treatment was chosen, considering its possible
complications, especially in young children. Elevation of the depressed skull fracture
was made using a vacuum extractor (pediatric oxygen mask, connected to a vacuum source).
The procedure was conducted under sedation and lasted ∼ 15 minutes. No complications
occurred in the postprocedural period. Postoperative CT scan shows adequate resolution
of depressed skull fracture ([Fig. 3]). Note: the patient's parents agreed with the publication of the images submitted
in the present article, for scientific purposes only, without any form of identification
through the subject's name or hospital records.
Fig. 1 Depressed skull fracture – physical Exam.
Fig. 2 Computed tomography scan of the head – preprocedure.
Fig. 3 Computed tomography scan of the head – postprocedure.
Discussion – Treatment Modalities
Discussion – Treatment Modalities
Depressed skull fractures, by definition, are caused by relatively high kinetic energy
traumas, capable of promoting displacement of bone fragments toward the interior of
the skull.[1]
[3]
[4]
[5] In this specific lesion, the largest area of bone depression may be located at or
adjacent to the fracture interface and the intact cranial surface, when multiple fragments
are displaced perpendicular to the cranial surface.[1]
[3]
[7] Ping pong fracture is a special type of depressed fracture, commonly found in neonates
and young children, who are victims of low kinetic brain injury.[8]
[9] In such cases, a skull bone depression occurs, without necessarily demonstrating
a fracture line in radiological studies, similar to a greenstick fracture. It occurs
mainly due to the smaller thickness and density, and greater resilience of bone tissue
in this population, and is rarely associated with intracranial lesions.[10]
In 25% of the cases, patients do not have any focal deficits or other neurological
complications, such as an altered level of consciousness or seizures. Another 25%
may have only a brief loss of consciousness. However, in a large number of cases,
surgical treatment is indicated, for several purposes: relief of pressure on the underlying
brain parenchyma, at the fracture location (with subsequent increase in cortical blood
flow), reduction of the risk of future epilepsy, correction of cosmetic deformities
and prevention of infection (in open fractures).[3]
[11]
[12]
The standard treatment for depressed skull fractures is the surgical elevation of
bone fragments back to their normal position. The procedure is indicated when the
area of bone depression is larger than the full thickness of the affected bone. In
simple depressed fractures, without injury to the dura and underlying parenchyma,
surgical treatment is brief, based on exposure of the bone defect and deformity correction.
In cases where there are dural lesions and injury to the brain parenchyma, as well
as gross contamination (in open fractures), it is imperative to perform more aggressive
treatment, with debridement of devitalized tissues, hemostasis and hermetic closure
of the dura mater.[3]
[13]
[14]
Discussion – Physical Aspects
Discussion – Physical Aspects
It is important to describe the physical aspects that are responsible for the success
of the vacuum-suction procedure in the treatment of depressed skull fractures. First,
to understand the concept of vacuum, created within the dome of the object, applied
over the skull, it is necessary to understand the concept of pressure.
Pressure is known to be a physical quantity that measures how much force is being
exerted per unit area. The unit of measure used in the international system is newton/meter2 (N/m2), which is related to atmospheric pressure. The value of 1 atm represents the action
of the weight of the atmospheric air layer (force weight) per unit surface area of
the earth at sea level (atmospheric pressure reference). The ratio between these two
units is 1 atm = 100,000 N/m2. Considering the gravitational acceleration of the Earth close to 9.8 m/s2, for each 1 m2 of area (the average human body has an area of 1.90 m2 for men and 1.6 m2 for women), the human being is subjected to an atmospheric pressure equivalent to
the weight created by a mass of 10 tons.[15] The reason our body is not overwhelmed by the action of the earth's atmosphere is
that we have an internal body pressure that balances with the external pressure of
the atmosphere, as with an open container completely filled with air. Therefore, the
internal pressure of the object, and the external pressure of the atmosphere, exert
on its walls equivalent force vectors, from inside to outside, and from outside to
inside (same area, same pressure, therefore, same forces) ([Fig. 4]). If we remove the internal pressure from the container, we will establish the vacuum
([Fig. 5]). In the absence of pressure in its interior, external forces, caused by the still
existing atmospheric pressure, will overwhelm the stability of the object itself,
making it easy to be crushed, like a plastic bottle or a metal can.
Fig. 4 Force vectors on the skull.
Fig. 5 Vacuum suction effect on force vectors.
The presence of force vectors caused by the atmospheric pressure are extremely powerful
and, inside the skull, they can overlap the resistance of its vault, in the absence
or in a great reduction of external force vectors, a phenomenon established by the
reduction of the pressure on the vacuum suction device (vacuum setting or pressure
reduction). As shown in the [Fig. 5], the internal pressure around the lesion is the same, and the magnitude of the forces
acting on each unit of area will be equal at all points of contact. This is the rationale
that justifies why the vacuum suction therapy is more homogeneous than a conventional
manual surgical intervention.[15]
Analyzing [Fig. 4], one can notice the action of three force vectors on the skullcap, in symmetrical
and central positions to the lesion. It is noted that, by decomposing the lateral
symmetrical forces, the components that are in the direction of the central force
are responsible for reconstituting the cranial box back to its shape, prior to the
deformation. Each component of the lateral internal forces in this direction (Fy)
has, in the least deformed part, a magnitude smaller than that of the central force,
corroborating the presumption that the vacuum suction is a smoother and more homogeneous
procedure than the conventional ones.
Discussion – Surgical versus Nonsurgical Treatment
Discussion – Surgical versus Nonsurgical Treatment
Although morbidity and mortality associated with surgical treatment is small, all
patients undergoing this treatment modality are at risk, ranging from local complications
(infections, hematomas) to death. Other disadvantages are the prolongation of hospitalization,
in all its medical, social and economic aspects, and the anesthetic risks associated
with surgical treatment.[1]
[13] These details become even more important in addressing the pediatric population,
because of their greater vulnerability to the possible complications associated to
the procedure. On account of the above, the possibility of conservative and noninvasive
treatments has become an increasingly frequent reality.[16]
In newborns, the fact that there is continuous brain growth during development, positively
contributes to skull remodeling and, over the years, there is a tendency to attenuation
of the depressed area. As ping-pong fractures are more frequent in this population,
they may not require surgery during their treatment.[4]
[17]
[18]
Several less invasive modalities of treatment have been proposed over the years, in
a continuous process of updating and inventing new techniques. One is the correction
of the bone depression with the use of vacuum suction. The technique was first described
in the literature in 1985.[1]
[12]
[19] This procedure has the advantages of its efficiency, practicality and safety. Moreover,
it avoids complications associated with the anesthetic procedure and those inherent
to a craniotomy or trepanation during invasive approaches.[8]
[13] The proposed technique uses the principle of local negative pressure establishment,
with traction of the affected bone segment to its previous position, and its main
object of treatment is focused on ping pong fractures. Although directed predominantly
to the pediatric population (especially < 2 years old), some authors have already
been successful in treating older individuals. The greatest extreme ever reported
in the literature was the treatment of a depressed fracture of a 17-year-old girl.[8]
[13]
The procedure is performed briefly and without the need for general anesthesia. Using
appropriate equipment to create a negative pressure gradient, it is attached to the
patient's scalp surface, on the topography of the bone defect, and is performed for
only a few seconds, with light traction over it, until adequate clinical results are
evident (reduction of bone and soft tissue retraction). The use of obstetric vacuum
extractors and milk suction pumps for this purpose has been reported in the literature.[13]
[20]
The complications associated with the procedure reported in the literature are minimal,
and are restricted to local complications, such as bruises and subgaleal edema, which
resolve spontaneously.[3] However, attention should be paid to the possibility of more serious lesions, such
as intracranial hematomas, that may develop after traction of the bone board and adjacent
structures. Radiological control (head CT scan) after the procedure may help in the
detection of incipient complications. It is also of great importance that the attending
physician pay attention to the accurate diagnosis of the type of fracture and the
possibility of associated intracranial injuries. The presence of complications such
as dural laceration, subdural and epidural hematomas, and open depressed fractures
still deserve standard surgical treatment, to achieve better outcomes for the patient.[13]
[14]
Conclusion
The use of vacuum suction for the treatment of depressed skull fractures has proven
to be an important tool for the neurosurgeon, especially when it comes to the pediatric
population. The low rate of associated complications, the absence of the need to subject
the patient to surgical stress and all its deleterious effects, and the reduction
of procedure-related costs, confirm the excellence of this treatment method, as long
as it is well indicated. The possibility of creating specific protocols for the management
of depressed fractures, including this nontraditional method of treatment, may be
a convenient reality in the future.
