missile injuries of the anterior skull base usually occur during war or warlike situations ; however , in the united states ,  >  100 americans die by suicide on an average day , and  50 of these suicides involve the use of firearms.1 the anterior skull base is the most common region of the skull base injured by a cranial missile .
most csf leaks can be broadly classified into traumatic ( most frequent ) , nontraumatic ( tumors ) , spontaneous , and iatrogenic.2 the clinical presentation usually is of unilateral clear rhinorrhea that can be continuous or persistent .
the patient can complain of a saltwater taste sensation ; fewer patients experience a sweet taste sensation .
also , the halo sign ( clear ring surrounding a central bloody spot on gauze ) can be present .
high - resolution computer tomography ( ct ) is a vital diagnostic and planning tool in patients with cranial and maxillofacial trauma .
ct cisternography , radionuclide cisternograms , magnetic resonance imaging ( mri ) , -2 transferrin , and intrathecal fluorescein are also part of the armament used in the diagnosis of csf leaks .
the goals of surgery in patients with gunshot wounds to the head are to evacuate a hematoma , achieve hemostasis , debride the wound , provide dural closure , and repair the skull base .
we present two cases of patients with csf leak after gunshot wound to the skull base .
a 16-year - old young man with a history of a self - inflicted gunshot wound with point of entry through the mouth with a 3-cm exit wound on top of the head .
( a ) noncontrast axial computed tomography consistent with a gunshot wound with entry point at the left parasagittal midline hard plate ( white arrow ) .
( b ) fracture of the inner table of both frontal sinuses with multiple fragments within the frontal sinuses and along the interhemispheric fissure ( white arrow ) .
( c ) the trajectory coursed cranially through the left nasal cavity , left ethmoid air cells , left frontal lobe , and exited through the left frontal bone .
( d ) posterior intracranial view shows missile trajectory entering through the skull base and exiting through the left frontal bone ( arrow ) .
the patient underwent endoscopic reduction and debridement of a frontal sinus encephalocele and csf leak repair .
the bone fragments were debrided as well as the brain tissue within the cavity . a large posterior table defect in the left frontal sinus
the brain tissue was covered with duragen ( integra lifescience corporation , plainsboro , new jersey , united states ) .
the mucosa of the frontal sinus was removed , and abdominal fat was packed to obliterate the cavity .
a mucosal graft was not feasible due to the location and extent of the defect .
to date the patient is without any complaints of clear rhinorrhea or a salty taste sensation .
nasal endoscopy shows a bilateral patent frontal sinus recess with no evidence of obstruction or drainage .
( a ) sagittal magnetic resonance t1 fluid - attenuated inversion recovery scan shows postoperative result of frontal sinus obliteration and frontal sinus encephalocele repair . bilateral frontal cortical and subcortical encephalomalacia from sequela from gunshot wound injury ( arrow , a and b ) .
( b ) residual pneumatization of the left frontal sinus ( arrowhead , a and b ) .
no evidence of frontal sinus mucocele formation . a 19-year - old female patient presented with a self - inflicted gunshot wound to the right frontal lobe with right intracerebellar hematoma . upon arrival
, neurosurgeons performed a first attempt to repair the frontal sinus floor with an inner table of bone flap .
the bullet involved the frontal sinus , the posterior ethmoid , nasal septum , right sphenoid sinus , and medial pterygoid plate with a major bullet fragment lodged into the right , at c2-c3 vertebral level , without lesions of the cervical spine .
( a ) coronal head computed tomography ( ct ) shows the skull base fracture ( arrow ) .
( b ) sagittal view of head ct shows bullet entry in the forehead through the anterior and posterior walls of the right frontal sinus ( arrow ) .
one month after discharge , the patient was complaining of right - sided clear rhinorrhea , with no salty taste sensation in her mouth .
postfrontal craniectomy ct was done , and the patient was scheduled for endoscopic csf leak repair ( fig .
right anterior ethmoidal air cells opacification ( arrowhead ) with fracture of ethmoid sinus roof ( arrow ) .
then 0.1 ml of preservative - free 10% fluorescein was mixed with 10 ml of csf and slowly injected intrathecally over 30 minutes .
the sites of the csf leak were identified at the ethmoid frontal junction anteriorly and in the posterior ethmoidal cells .
previous harvested abdominal fat was positioned at the site of the leaks , which resulted in cessation of the fluorescein - identified leak .
both grafts were supported with surgicel ( ethicon , inc . , somerville , new jersey , united states ) followed by duraseal ( confluent surgical , inc . , waltham , massachusetts , united states ) .
nexfoam ( hemostasis , saint paul , minnesota , united states ) were placed to further support the graft , and two merocels ( medtronic , mystic , connecticut , united states ) were placed in the right nasal cavity . to date there is no evidence of csf leak .
a 16-year - old young man with a history of a self - inflicted gunshot wound with point of entry through the mouth with a 3-cm exit wound on top of the head .
( a ) noncontrast axial computed tomography consistent with a gunshot wound with entry point at the left parasagittal midline hard plate ( white arrow ) .
( b ) fracture of the inner table of both frontal sinuses with multiple fragments within the frontal sinuses and along the interhemispheric fissure ( white arrow ) .
( c ) the trajectory coursed cranially through the left nasal cavity , left ethmoid air cells , left frontal lobe , and exited through the left frontal bone .
( d ) posterior intracranial view shows missile trajectory entering through the skull base and exiting through the left frontal bone ( arrow ) .
the patient underwent endoscopic reduction and debridement of a frontal sinus encephalocele and csf leak repair .
the bone fragments were debrided as well as the brain tissue within the cavity . a large posterior table defect in the left frontal sinus
the brain tissue was covered with duragen ( integra lifescience corporation , plainsboro , new jersey , united states ) .
the mucosa of the frontal sinus was removed , and abdominal fat was packed to obliterate the cavity .
a mucosal graft was not feasible due to the location and extent of the defect .
to date the patient is without any complaints of clear rhinorrhea or a salty taste sensation .
nasal endoscopy shows a bilateral patent frontal sinus recess with no evidence of obstruction or drainage .
( a ) sagittal magnetic resonance t1 fluid - attenuated inversion recovery scan shows postoperative result of frontal sinus obliteration and frontal sinus encephalocele repair . bilateral frontal cortical and subcortical encephalomalacia from sequela from gunshot wound injury ( arrow , a and b ) .
( b ) residual pneumatization of the left frontal sinus ( arrowhead , a and b ) .
a 19-year - old female patient presented with a self - inflicted gunshot wound to the right frontal lobe with right intracerebellar hematoma . upon arrival , neurosurgeons performed a first attempt to repair the frontal sinus floor with an inner table of bone flap .
the bullet involved the frontal sinus , the posterior ethmoid , nasal septum , right sphenoid sinus , and medial pterygoid plate with a major bullet fragment lodged into the right , at c2-c3 vertebral level , without lesions of the cervical spine .
( a ) coronal head computed tomography ( ct ) shows the skull base fracture ( arrow ) .
( b ) sagittal view of head ct shows bullet entry in the forehead through the anterior and posterior walls of the right frontal sinus ( arrow ) .
one month after discharge , the patient was complaining of right - sided clear rhinorrhea , with no salty taste sensation in her mouth .
postfrontal craniectomy ct was done , and the patient was scheduled for endoscopic csf leak repair ( fig .
right anterior ethmoidal air cells opacification ( arrowhead ) with fracture of ethmoid sinus roof ( arrow ) .
then 0.1 ml of preservative - free 10% fluorescein was mixed with 10 ml of csf and slowly injected intrathecally over 30 minutes .
the sites of the csf leak were identified at the ethmoid frontal junction anteriorly and in the posterior ethmoidal cells .
previous harvested abdominal fat was positioned at the site of the leaks , which resulted in cessation of the fluorescein - identified leak .
both grafts were supported with surgicel ( ethicon , inc . , somerville , new jersey , united states ) followed by duraseal ( confluent surgical , inc . , waltham , massachusetts , united states )
. nexfoam ( hemostasis , saint paul , minnesota , united states ) were placed to further support the graft , and two merocels ( medtronic , mystic , connecticut , united states ) were placed in the right nasal cavity . to date there is no evidence of csf leak .
csf is an ultrafiltrate of plasma produced by the choroid plexus that offers mechanical and immunologic protection for the brain .
a csf rhinorrhea is defined as a fistula between the dura and the skull base with csf discharge through the nose.3 about 70 to 80% of csf leaks are secondary to trauma and evident within the first 2 days , first week , or within the first 3 months.2 
 4 energy deposited along the missile trajectory shatters the bone and lacerates soft tissues , which makes it difficult to diagnose a csf leak upon arrival.5 also , the surrounding edema associated with the trauma can conceal these leaks momentarily , so csf leaks can be revealed after this edema subsides or necrosis of the surrounding tissues occurs .
the greatest concern with a csf leak is the potential for meningitis , with a generally accepted rate of 10%.6 approximately 35% of patients with recurrent meningitis have csf leaks secondary to trauma.2 a missile traversing the face creates a communication between air - filled mucus - secreting cavities and the subarachnoid spaces with wound contamination through the missile entry point from oropharyngeal commensal staphylococcus , gram - negative or gram - positive rods.7 a 2006 cochrane review8 concluded that no evidence indicates that prophylactic antibiotics reduce the risk of meningitis in patients with skull base fractures with active csf leak .
however , there are no data to apply this statement to patients with gunshot wounds to the head .
high - resolution ct is vital for the planning and prognosis of patients with a gunshot wound to the head ; it is also the preferred method to localize the site of a skull base fracture .
however , ct cisternography or mri may be required to diagnose csf rhinorrhea . in the presence of a skull base fracture on ct and a clinical csf leak ,
there is no need for a further confirmatory test . in cases where a confirmatory test is needed , the -2 transferrin assay is the test of choice because of its high sensitivity and specificity.4 
 9 
  intrathecal fluorescein has been used to confirm and intraoperatively localize csf leaks.2 
 4 the recommended dilution is 0.1 ml of 10% intravenous fluorescein in 10 ml of the patient 's own csf that is infused slowly over 30 minutes .
a yellow fluid leaking in the nose should be visualized in the vicinity of the defect , and the use of a blue - light filter makes the sensitivity even higher .
patients with csf leaks  <  7 days have an 11% chance to develop meningitis versus 88% of those lasting  >  7 days .
surgical treatment is indicated when they last  >  1 or 2 weeks.10 patients with increased intracranial pressure , such as those who experience intracranial trauma , make hernias at points of weakness ; these patients have a less successful rate of csf leak closure and more risk of developing meningoencephalocele.4 nonetheless , the success rate of surgical closure is 95% for csf leaks associated with trauma.11 
  in patients with a gunshot wound to the head , neurosurgical intervention is usually required , so it is reasonable to repair an evident csf leak .
however , when intracranial trauma is present , the associated significant brain edema makes an early repair likely to fail because of elevated intracranial pressure . in agreement with other authors,12 
 13
we believe the use of a lumbar drain does not provide an additional benefit in the treatment of csf leaks associated with gunshot wounds to the head , especially because of the risk of overdrainage and the resultant pneumoencephalos .
endoscopic closure of csf leaks was first described by wigand in 1981 , and to date , it continues to be the preferred method of csf leak closure because of its high success rate ( 9097%).2 
 3 
 4 
 9 
 10 
 14 in cases of trauma , an open approach for repair of these lesions is still favored .
we present two cases where satisfactory endoscopic csf leak repair was performed after gunshot wound to the head .
the primary goal of the repair is to separate the intracranial from the extracranial spaces . in the cases
presented , an endoscopic repair was favored to minimize brain manipulation of an already severely injured brain .
cranial base repair with fat and/or mucosa is utilized in other instances and highly successful .
postoperative recommendations are 30 degrees of head elevation , bed rest , stool softeners , antiemetics , blood pressure management , and recommendations to refrain from sneezing , nose blowing , coughing , and valsalva maneuvers .
endoscopic closure of anterior skull base csf leaks is now recognized as the treatment of choice for most csf leaks . in those cases resulting from firearm injuries ,
treatment should be decided by the severity of neurologic deterioration throughout the emergency period and the existence or absence of associated intracranial lesions .
the risk of suppurative sequelae in patients with a missile trajectory though the skull base are high , especially when the sinuses have been compromised , so the timing for surgery should be decided with great care and with a multidisciplinary approach . in selected patients in whom
the primary concern is the repair of a csf leak and there is no need to address intracranial injuries , an endoscopic endonasal repair can be safe and effective .
 
 objectives  to describe two cases of cerebrospinal fluid ( csf ) leak repair after gunshot wound to the head . 
 design  retrospective review of two cases . 
 
 settings  a large regional tertiary care facility . 
 
 participants  two patients with gunshot wounds to the skull base . 
 
 main outcome measures  preoperative and postoperative physical and radiologic findings . 
 
 results  patients in this series underwent endoscopic surgery , debridement , and repair of csf leaks after gunshot wounds to the head . to date , the patients are without csf leak 
 . 
 conclusions  endoscopic closure of anterior skull base csf leaks in patients with gunshot wounds can be safe and effective . 
 treatment should be decided by the severity of neurologic deterioration throughout the emergency period and the existence or absence of associated intracranial lesions . 
 timing for surgery should be decided with great care and with a multidisciplinary approach . 
Introduction
Case Report
Case 1
Case 2
Discussion
Conclusion