CSF Fistulas Following Frontal Sinus Fractures
CSF Fistulas Following Frontal Sinus Fractures
The diagnostic workup for patients with significant facial trauma includes a myriad of imaging techniques that vary depending on the mechanism of injury and clinical suspicion. For patients injured as a result of severe blunt trauma that experience an alteration in consciousness, a noncontrast head CT scan is the imaging modality of choice. This technique provides an excellent investigation of the brain parenchyma to evaluate for the presence of intracranial hemorrhage and contusion. Additionally, these high-resolution examinations allow for quality inspection of the bone structures of the face and frontal sinus. Postprocessing 3D reconstruction can be performed by either the surgeon or radiologist, to further aid in diagnosis or surgical planning. If a CSF leak is suspected in the setting of rhinorrhea or otorrhea, a fluid sample can be sent for β-2 transferrin analysis. In cases of suspected persistent occult CSF fistulas, radionuclide cisternography, CT myelography, MR phase-contrast cisternography and 3D CISS sequences, and intrathecal administration of fluorescein can aid in diagnosis.
Ultimately, with frontal sinus fractures, the goal of initial management is to correct the cosmetic deformity while anticipating and preventing the development of immediate and late-term morbidities related to infection and CSF fistulas. It is also the responsibility of the treating surgeon to avoid unnecessary interventions when they have no proven benefit. The risk of morbidity related to any procedure to treat frontal sinus fractures must be weighed against the anticipated morbidity of declining or delaying intervention.
Treatment options include observation, reconstruction, obliteration, cranialization, or a combination thereof. The optimal management of frontal sinus fractures is controversial and varies between providers and institutions. The need for complex surgical procedures involving obliteration or cranialization is based on the extent of involvement of the anterior wall, posterior wall, and nasofrontal tract injury, in addition to the presence of a CSF fistula. Commonly, if posterior table involvement is present, especially with any CSF fistulas suspected to be related to the fracture, aggressive surgical intervention is commonplace. This aggressive intervention involves obliteration and cranialization of the frontal sinus. In the obliteration portion, all of the sinus contents and mucosa are removed via a bifrontal craniotomy with a combination of a high-speed drill and bipolar electrocautery. Frequently, an alternative substance is used to replace the space that is created. Frontal sinus obliteration can be performed using Gelfoam, bone chips, adipose tissue (autograft), temporalis fascia, pericranium, bioglass, polytetrafluoroethylene/carbon fiber, calcium sulfate, methylmethacrylate, oxidized cellulose, hydroxyapatite, or lyophilized cartilage. The cranialization aspect of the procedure specifically relates to the elimination of the entire posterior wall, and the brain contents are allowed to fill the sinus space. Typically, a vascularized pedicled pericranial flap is procured and sutured to the inferior anterior skull base, forming a watertight seal between the brain and remnant of the frontal sinus. Alternative techniques include the use of allograft dural substitute material. Depending on surgeon preference, along with the possible need for intracranial pressure monitoring related to traumatic brain injury, CSF diversion is employed at the time of initial operation or subsequently at the development of CSF fistulas. This can be performed using either a ventriculostomy, a lumbar drain, or serial lumbar CSF taps. These techniques are not universally used at the time of initial operation, but sometimes are employed when the assessment of the integrity of repair dictates an additional maneuver to improve the chances of success. There is no study comparing one method of CSF diversion to another or assessing whether its routine use prevents delayed CSF leakage. If a CSF fistula develops in the acute postoperative period, either as evidenced by otorrhea or rhinorrhea, then CSF diversion is used for a period of several days in an attempt to remove any pressure from the operative bed. This maneuver allows tissues to heal and prevents further CSF leakage. Reoperation always exists as a treatment option, but the potential morbidity associated with reoperation should be taken into consideration.
Because frontal sinus fractures encompass such a heterogeneous injury pattern, prospective, randomized trials regarding the optimal management of frontal sinus fractures do not exist and we rely on the reports from the vast experience of several high-volume centers. In this paper, we review the major patient series reporting on the management of frontal sinus fractures, with an emphasis on the concurrent treatment or avoidance of CSF fistulas.
Diagnosis
The diagnostic workup for patients with significant facial trauma includes a myriad of imaging techniques that vary depending on the mechanism of injury and clinical suspicion. For patients injured as a result of severe blunt trauma that experience an alteration in consciousness, a noncontrast head CT scan is the imaging modality of choice. This technique provides an excellent investigation of the brain parenchyma to evaluate for the presence of intracranial hemorrhage and contusion. Additionally, these high-resolution examinations allow for quality inspection of the bone structures of the face and frontal sinus. Postprocessing 3D reconstruction can be performed by either the surgeon or radiologist, to further aid in diagnosis or surgical planning. If a CSF leak is suspected in the setting of rhinorrhea or otorrhea, a fluid sample can be sent for β-2 transferrin analysis. In cases of suspected persistent occult CSF fistulas, radionuclide cisternography, CT myelography, MR phase-contrast cisternography and 3D CISS sequences, and intrathecal administration of fluorescein can aid in diagnosis.
Management Strategies
Ultimately, with frontal sinus fractures, the goal of initial management is to correct the cosmetic deformity while anticipating and preventing the development of immediate and late-term morbidities related to infection and CSF fistulas. It is also the responsibility of the treating surgeon to avoid unnecessary interventions when they have no proven benefit. The risk of morbidity related to any procedure to treat frontal sinus fractures must be weighed against the anticipated morbidity of declining or delaying intervention.
Treatment options include observation, reconstruction, obliteration, cranialization, or a combination thereof. The optimal management of frontal sinus fractures is controversial and varies between providers and institutions. The need for complex surgical procedures involving obliteration or cranialization is based on the extent of involvement of the anterior wall, posterior wall, and nasofrontal tract injury, in addition to the presence of a CSF fistula. Commonly, if posterior table involvement is present, especially with any CSF fistulas suspected to be related to the fracture, aggressive surgical intervention is commonplace. This aggressive intervention involves obliteration and cranialization of the frontal sinus. In the obliteration portion, all of the sinus contents and mucosa are removed via a bifrontal craniotomy with a combination of a high-speed drill and bipolar electrocautery. Frequently, an alternative substance is used to replace the space that is created. Frontal sinus obliteration can be performed using Gelfoam, bone chips, adipose tissue (autograft), temporalis fascia, pericranium, bioglass, polytetrafluoroethylene/carbon fiber, calcium sulfate, methylmethacrylate, oxidized cellulose, hydroxyapatite, or lyophilized cartilage. The cranialization aspect of the procedure specifically relates to the elimination of the entire posterior wall, and the brain contents are allowed to fill the sinus space. Typically, a vascularized pedicled pericranial flap is procured and sutured to the inferior anterior skull base, forming a watertight seal between the brain and remnant of the frontal sinus. Alternative techniques include the use of allograft dural substitute material. Depending on surgeon preference, along with the possible need for intracranial pressure monitoring related to traumatic brain injury, CSF diversion is employed at the time of initial operation or subsequently at the development of CSF fistulas. This can be performed using either a ventriculostomy, a lumbar drain, or serial lumbar CSF taps. These techniques are not universally used at the time of initial operation, but sometimes are employed when the assessment of the integrity of repair dictates an additional maneuver to improve the chances of success. There is no study comparing one method of CSF diversion to another or assessing whether its routine use prevents delayed CSF leakage. If a CSF fistula develops in the acute postoperative period, either as evidenced by otorrhea or rhinorrhea, then CSF diversion is used for a period of several days in an attempt to remove any pressure from the operative bed. This maneuver allows tissues to heal and prevents further CSF leakage. Reoperation always exists as a treatment option, but the potential morbidity associated with reoperation should be taken into consideration.
Because frontal sinus fractures encompass such a heterogeneous injury pattern, prospective, randomized trials regarding the optimal management of frontal sinus fractures do not exist and we rely on the reports from the vast experience of several high-volume centers. In this paper, we review the major patient series reporting on the management of frontal sinus fractures, with an emphasis on the concurrent treatment or avoidance of CSF fistulas.
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