This document provides an overview of post traumatic cerebrospinal fluid (CSF) leaks and basal skull fractures (BSF), including:
- Classification of CSF leaks as traumatic vs. nontraumatic and early vs. delayed. BSF are classified by location in the anterior, middle, or posterior cranial fossa.
- Epidemiology, pathophysiology, possible routes of CSF egress, natural history and management of CSF leaks. Conservative management includes bed rest, medications, and repeated lumbar punctures.
- Diagnostic workup includes clinical exam, imaging like CT cisternography, and intraoperative fluorescein to localize the leak.
- Treatment algorithms involve initial
Post traumatic csf leak & bsf mgt update finalllpptx
1. Post traumatic CSF
leak & BSF mgt update
By Dr.Mestet Y.(NSR3)
Moderator: Dr.Mersha (Consultant
Neurosurgeon)
5/14/2021
1
2. Outline
O Case
O Introduction
O Epidemiology of CSF leak
O Pathophysiology
O Routes of CSF leak
O Natural hx & Mgt of CSF leak
O Classification & mgt of BSF
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4. Introduction
O Traumatic cerebrospinal fluid (CSF)
fistulas typically result from a skull fracture
with associated durotomy and arachnoid
tear that result in drainage of CSF within
the nasal cavity, paranasal sinuses, or
middle ear.
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6. Epidemiology of traumatic
CSF fistula
O Occur in 2–3% of all patients with head injury,
60% occur within days of trauma, 95% within
3 months.
O The risk of CSF leak after a BSF is 10–30%
for adult patients.
O Cranionasal fstulas are more common than
cranioaural fstulas and less likely to cease
spontaneously.
O Tend to cease more often than spontaneous
CSF leak.
O less common in childhood.
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7. Time of leakage of CSF after Trauma
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O Early Onset
Within 48 hours.
O Delayed Onset
/Recurrence
• Shrinking of blood clot
or swollen brain
• Maturation and
shrinkage of the dural
scar
• Devascularization and
necrosis of the bone
and soft tissue
O Very-Late-Onset
first develop after a considerable
delay, or infection alone may be the
first sign of a fistula.
Possible explanations:
• Age-related shrinkage of brain
tissue that had been plugging
a dural defect
• A cerebral-dural scar formed from
contused brain tissue at the site of
the fstula, which sealed the tear but
did not provide a reliable barrier to
infection
• Growing fractures of the ethmoid
that lead to the formation
of a herniated encephalocele that
stretched and ruptured as a
result of intracranial pulsations35
8. Pathophysiology
O The dura is firmly adherent to the thin bone of
the cranial fossa floor and is readily torn by
fractured bone edges.
O Blunt Injury
O Penetrating Injury and Gunshot Wounds
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9. Possible routes of egress of CSF
1. mastoid air cells (e.g. vs)
2. sphenoid air cells (e.g.TSS)
3. cribriform plate/ethmoidal roof
4. frontal sinus air cells
5. herniation into empty sella and then into
sphenoid air sinus
6. along path of internal carotid artery
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10. Cont’d
7. Rosenmüller’s fossa:
8. site of the opening of the transient lateral
craniopharyngeal canal
9. percutaneously through a surgical or
traumatic wound
10. petrous ridge or internal auditory canal: #/VS
a) rhinorrhea: through middle ear → eustachian
tube → nasopharynx
b) otorrhea: via perforated tympanic membrane
→ external auditory canal
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11. 5 Possible routes for CSF rhinorrhea
following VS surgery
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12. Natural history of CSF leak
O less than 5% persisted more than 14
days.
O Most (80–85%) CSF otorrhea ceases in
5–
10 days.
O 70% of cases of CSF rhinorrhea stop
within 1 wk, and usually within 6 mos in
the rest.
O cessation of CSF leak is more likely in
MCF fractures (60%) than ACF fractures
(26.4%).
O meningitis, brain abscess, and tension
pneumocephalus.
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13. Meningitis in CSF fistula
O The most common organisms are
Streptococcus pneumoniae and Haemophilus
influenzae.
O Incidence with posttraumatic CSF leak: 5–
10%, increases as leak persists > 7 days
(50%).
O more common with spontaneous fistula.
O Meningitis may promote inflammatory
changes at the site of the leak, with a
resultant cessation of the leak. However,
this often proves to be a temporary
resolution, providing a false sense of
security.
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14. Presentation
O Rhinorrhea: commonest
The side cannot be relied on to locate the
fistula. (paradoxical rhinorrhea)
O Otorrhea
O Otorhinorrhea
O Oculorhinorrhea
O Headaches: high pressure or low
pressure.
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15. workup
O Clinical exam
“Ring /halo/target/ sign”
Reservoir sign:
Handker chief test:
O Lab
Quantitative fluid glucose
Glucose oxidized test in glucose oxidase strips
A chlorine concentration
B2-transferrin: penetrating eye injury
B-trace protein
O Imaging
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18. Localization of CSF leakage
intraoperatively
O Fluorescein lumbar puncture: commonest
method.
O Fluorescein-soaked cotton pledget applied
adjacent to the site of suspected fracture;
resulting in greenish discolouration of
the yellow fluorescein dye.
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19. Conservative mgt
O measures to lower ICP:
a) bed rest:
b) avoid straining & avoid blowing nose
c) acetazolamide
d) modest fluid restriction; 75% of maintenance/day
2. if leak persists (caution: fir CLD st R/O obstructive hydrocephalus with CT
or MRI)
a) LP: q d to BID OR with/without/ CLD (chamber at shoulder level &open vs ●
allow 15–20 cc to drain, then clamp tubing. Repeat q 1 hour)
If patient deteriorates with CLD drain in place: immediately stop
drainage, place patient flat in bed (or slight Trendelenburg), start 100% O2,
get CT or bedside cross-table skull X-ray (to R/O tension
pneumocephalus due to drawing in of air)
O Avoid NG-tube ( 64 % mortality).
O Prophylactic antibiotics/vaccination???
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21. Graft options
O Vascularised grafts such as pericranium, temporalis muscle, fascia
and septal mucosa; resist infection, incorporate more quickly into
the recipient site, and appear to provide a more durable closure.
O Fat is the preferred nonvascularised graft due to angiogenic factors
that can aid recruitment of the surrounding blood vessels. Fat also
has a low metabolic requirement, resisting necrosis and scarring.
O Muscle can undergo fibrosis and atrophy resulting in graft failure.
Other nonvascularised grafts such as harvested temporalis
fascia and fascia lata are commonly used.
O Autologous bone graft can be harvested from the vomer, split
calvarium, iliac crest or rib and cartilage grafts can be harvested.
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22. Postoperative CSF leak mgt
O In general, postoperative CSF leak (including
rhinorrhea) is best addressed with immediate
surgical re-exploration.
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23. BSF
O Incidence in decreasing order in TBI:
anterior cranial fossa (ACF), middle
cranial fossa (MCF) and posterior cranial
fossa (PCF).
O PCF fractures is divided into occipital
condylar fractures (OCF) and clival
fractures (CF).
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24. Radiographic diagnosis
O Direct radiographic findings :appear as
linear lucencies through the skull base on
CT scan
O Indirect radiographic findings :
Pneumocephalus (diagnostic of BSF in
the absence of an open fracture of the
cranial vault),
air/fluid level within or opacification of air
sinus with fluid (suggestive).
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27. Cont’d
O The tympanic membrane
O CSF leaks route
CSF fstulas occur with equal frequency with either type of fracture.
Posterior cranial BSF
O Condylar #: longitudinal (37.5%), transverse
(37.5%) or oblique fractures (29.4%).
O Longitudinal fractures have higher mortality rates (60–80%) than
transverse (25–50%)
and oblique fractures (25–40%) due to recurrent posttraumatic
vasospasm of the carotid artery and entrapment of the basilar
artery which can lead to brainstem ischemia.
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29. Treatment of the BSF
O Most do require conservative RX.
1. “traumatic aneurysms”
2. posttraumatic carotid-cavernous fistula
3. CSF fistula:
4. meningitis or cerebral abscess:
5. cosmetic deformities
6. posttraumatic facial palsy
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30. References
O Greenburg 9th edition
O Youman 7th edition
O Journal of neurosurgery
O British journal of neurosurgery
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Notas del editor
High- and Low-Pressure Leaks In the early stages after severe head injury, potentially increased ICP may be partly “controlled” by a CSF leak, but in most instances, persistent fstulas are not associated with increased ICP. High-pressure leaks are more common with spontaneous, nontraumatic CSF leakage; however, if the leak is accompanied by posttraumatic hydrocephalus, it may be maintained by the high CSF pressure, and the hydrocephalus should be managed initially by insertion of a lumboperitoneal shunt.29
Cerebrospinal Fluid Fistulas in Children CSF fstulas are less common in childhood; only 15% occur in children younger than 15 years. The frequency in children is low partly because of a lower frequency of frontal impact but also because of the greater flexibility of the cartilaginous components of the skull base and underdevelopment of the sinuses.27 The frontal sinus is not developed until the age of 4 years or older. The ethmoid sinuses are present at birth and enlarge rapidly, but the ethmoid component of the anterior fossa is cartilaginous and therefore flexible at birth. By the age of 3 years, the size proportion of the nasoethmoid cavities is equivalent to that in adults. The sphenoid sinus is very small at birth and becomes related to the anterior fossa between the ages of 5 and 10 years. The tegmen tympani is thin and rigid at birth, and a fstula to the middle ear can occur. Mastoid air cells are very small at birth but increase up to the age of 5 years
Delayed Onset or Recurrence A CSF leak may be delayed in onset or recur after a period of cessation. Possible reasons for this are as follows: • Shrinking of blood clot or swollen brain that was adhering to the dural-arachnoid tear and preventing healing3 • Maturation and shrinkage of the dural scar30,31 • Devascularization and necrosis of the bone and soft tissue9 Very-Late-Onset Cerebrospinal Fluid Leakage or Infection CSF rhinorrhea may frst develop after a considerable delay, or infection alone may be the frst sign of a fstula. Delayed meningitis without a history of CSF rhinorrhea has been reported up to 48 years after the original head injury, which might have been quite minor.32-34 Possible explanations for this are as follows: • Age-related shrinkage of brain tissue that had been plugging a dural defect • A cerebral-dural scar formed from contused brain tissue at the site of the fstula, which sealed the tear but did not provide a reliable barrier to infection • Growing fractures of the ethmoid that lead to the formation of a herniated encephalocele that stretched and ruptured as a result of intracranial pulsations35 Delayed onset or recurrence The delayed onset group is defined as patients with CSF leak presented at least 1 week after trauma. CSF leakage may be delayed even if there is no CSF leakage at first. Usually they can be healed spontaneous or lumbar drainage may be required for further treatment. Even if the CSF leakage was healed, there were also possibility of delayed CSF leakage. There were two reasons of the delayed onset or recurrence of CSF leakage: 1) blood clot disappears; 2) separation of dura and arachnoid caused by cerebral edema subsides.15) Very-Late Onset or Infection CSF leakage may also occur after a considerable period of time, and even before CSF leakage occurs, such as rhinorrhea, infection may occur. The reason for this is that brain shrinkage caused by age may cause CSF leaking site reopening, growth fracture on ethmoidal bone may lead to leakage to fracture site, CSF leaking site has a barrier, which can’t work as an infection barrier, could be considered.
Blunt Injury Traumatic CSF fstulas usually occur with fractures of the anterior and middle cranial fossae. Less commonly, a posterior fossa fracture may extend through the petrous bone to the middle ear or through the clivus to the sphenoid sinus.
Rosenmüller’s fossa: located just inferior to cavernous sinus, may be exposed by drilling off anterior clinoids to allow access to ophthalmic artery aneurysms
● ① via the apical cells to the tympanic cavity (TC) or eustachian tube (the most common path) ● entry into the bony labyrinth—reaching the middle ear would require rupture e.g. of the oval window by overpacking bone wax into the labyrinth) ○ ② through the vestibule of the horizontal semicircular canal (SCC) ○ ③ through the posterior SCC (the posterior SCC is the most common area that is entered by drilling) ● ④ follows the perilabyrinthine cells and tracts to the mastoid antrum ● ⑤ through the mastoid air cells surgically exposed at the craniotomy site Most leaks are diagnosed within 1 week of surgery, although 1 presented 4 years post-op.53 They appear to be more common with more lateral unroofing of the IAC.53 Meningitis complicates a CSF leak in 5–25% of cases, and usually develops within days of the onset of leak.53 Hydrocephalus may promote the development of a CSF fistula. Treatment: 25–35% of leaks stop spontaneously (one series reported 80%).53 Treatment options include: 1. non-surgical: a) elevate HOB b) a percutaneous lumbar subarachnoid drain may be tried,54,55 although some debate its efficacy,48 and there is a theoretical risk of drawing bacteria into the CNS 2. surgical treatment for persistent leaks: In general, postoperative CSF leak (including rhinorrhea) is best addressed with immediate surgical re-exploration a) in the case of a translabyrinthine approach with absent ipsilateral hearing: to treat rhinorrhea, pack and permanently close the Eustachian tube via a trans tympanic membrane approach. This is very effective and avoids re-opening the surgical incision and removing the previously placed fat graft. b) if hearing is preserved (which excludes translab), every effort should be made to preserve the Eustachian tube function to preserve middle ear function. Re-explore the surgical field, rewax the aircells and place additional fat graft, fascia, pericranium, or other sealant over the exposed aircells. This aggressive management is the most definitive and rapid treatment, and avoids prolonged bed rest required by placing a lumbar drain and trying to control the leak in a conservative way 3. a CSF leak may be an indication of altered CSF hydrodynamics. Most of these patients demonstrate frank ventriculomegaly (hydrocephalus). In some patients the leak may function as a pressure relief valve and thereby ameliorate the ventriculomegaly (i.e., there would be hydrocephalus if there wasn’t a leak). Adjunctive CSF shunting is usually also necessary or the repair will be more likely to fail
The risk of meningitis is highest within the frst year of CSF leak.4 Therefore, upfront treatment is warranted, and a wide range of surgical options is available.4,5 Healing is not always reliable, and infection may occur many years later, even without any history of CSF leakage. Thus a history of head injury or severe facial fracture in a patient with meningitis or a brain abscess should prompt a search for a skull base fracture and fstula. Fistulas that do not heal or recur necessitate surgical treatment.
The side of rhinorrhea cannot be relied on to locate the fstula. Although usually ipsilateral to the fracture site, it is frequently contralateral or bilateral.
Headaches can be either high pressure or low pressure. A high-pressure headache may be experienced repeatedly as a steady buildup of pain that is relieved by fluid drainage. Lowpressure headaches are less marked in the recumbent position and are increased by the upright position. Rhinorrhoea usually occurs on the same side with respect to the skull fracture, but paradoxical rhinorrhoea can occur due to either a fracture of the midline structures or development of a meningocele obstructing the nostril on the affected side.
Oculorhinorrhea In rare cases, a cranio-orbital fracture together with a laceration of the conjunctival sac may allow CSF to leak from the eye.16,1 A conscious patient may complain of a nasal discharge or a salty taste in the back of the throat (because of the sodium content of CSF) or fullness of the ear with some hearing loss. jjjbgjj
Handker chief test: When the discharge from the nose is buried in a handkerchief or dry gauze, the CSF is more likely to be clear if it is not sticky The Handker chief test is a test to determine the nasal discharge, which is unclear and sticky due to mucin secretion from the nose. A chlorine concentration greater than 110 mEq/L also suggests that the fluid is probably CSF.4
β1-Transferrin is found in serum, tears, nasal secretions, and saliva. β2-Transferrin is found only in CSF, perilymph, and vitreous humor. It is important to determine the presence of penetrating eye injury before the β2-transferrin results are interpreted. Normal CSF glucose is > 30 mg% (usually lower with meningitis), whereas lacrimal secretions and mucus are usually < 5 mg%. A negative test is more helpful since it rules out CSF (except in hypoglycorrhachia (low glucose in the CSF)), but there is a 45–75% chance of false positive.
Glucose oxidized test: The CSF glucose from nasal or ear secretions has long been a classical method in testing CSF leak. In general, the glucose oxidase strips show positive result when the sample has a concentration over 20 mg/dL. Nasal discharge has a normal concentration of 10 mg of glucose, thus, if the glucose test is negative then it can be ruled out. However, it is only to be used as reference as it has high false positive and negative rates depending on the patients’ other medical conditions.6) Moreover, the lacrimal secretion can also be tested even if the concentration is less than 5 mg/dL. Meanwhile, a false positive result can be observed in the bloody nasal discharge whereas a false negative results are seen if the meningitis is already progressed in the patients. All these clinical conditions have to be considered before the interpretation and confirmation of the CSF leaks.
Accurate diagnosis of CSF rhinorrhea and otorrhea and precise localization of CSF leak helps in surgical planning and enhances chances of successful dural repair. The emphasis and onus of CSF repair has shifted towards endoscopic surgery. This requires accurate localization of the dural and osseous defects with imaging. This can be accomplished by HRCT imaging of the skull base. However, the utility of HRCT is limited in the presence of multiple osseous defects. The combination of 3DT2 DRIVE MR cisternography and HRCT imaging of the skull base allows accurate identification of the leak and the osseous defect necessary for planning of the endoscopic surgery. CT cisternography can be reserved for equivocal cases.
Water-soluble contrast CT cisternography Procedure of choice. This test is performed if: 1. no site identified on plain CT (with coronals) 2. when patient is leaking clinically (the site is only sometimes identified in the absence of an active leak) 3. when multiple bony defects are identified, and it is essential to determine which site is actively leaking 4. if a bony defect seen on plain CT does not have associated changes of abnormal enhancement of adjacent brain parenchyma Technique26: Use iohexol (p.236) 6–7 ml of 190–220 mg/ml injected into lumbar subarachnoid space via 22 gauge spinal needle (or 5 ml via C1–2 puncture). Patient positioned in -70° Trendelenburg × 3 min prone with neck gently flexed, in CT they are kept prone with head hyperextended with 5 mm coronal cuts with 3 mm overlap (use 1.5 mm cuts if necessary). May need Cerebrospinal Fluid 23 401 provocative maneuvers (coronal scans prone (brow up) or in position of leak, intrathecal saline infusion (requires Harvard pump)27…). Look for accumulation of contrast in air sinuses. Apparent discontinuity of bone on CT without extravasation of contrast is probably not the site of leakage (bone discontinuities may be mimicked by partial volume averaging on CT).
Non-surgical treatment 1. measures to lower ICP: a) bed rest: although recumbency may ameliorate symptoms, there is no other benefit from bed rest30 b) avoid straining (stool softeners) and avoid blowing nose c) acetazolamide (250 mg PO QID) to reduce CSF production d) modest fluid restriction; caution post-transsphenoidal because of possible DI (p.132): 1500 ml/day in adults, 75% of maintenance/day in peds 2. if leak persists (caution: first R/O obstructive hydrocephalus with CT or MRI) a) LP: q d to BID (lower pressure to near atmospheric or until H/A) OR b) continuous lumbar drainage (CLD): via percutaneous catheter. Two (of many) management options: ● keep HOB elevated 10–15° and place drip chamber at shoulder level (lower the chamber if leak persists) and leave open to drain (uses pressure to regulate drainage—may be dangerous e.g. if drainage bag falls to floor) ● allow 15–20 cc to drain, then clamp tubing. Repeat q 1 hour c) CLD may require ICU monitoring. If patient deteriorates with drain in place: immediately stop drainage, place patient flat in bed (or slight Trendelenburg), start 100% O2, get CT or bedside cross-table skull X-ray (to R/O tension pneumocephalus due to drawing in of air) Arguments against antibiotic prophylaxis are as follows: 1. The antibiotics commonly used penetrate CSF poorly. 2. The period of risk and hence the duration of prophylactic treatment beyond cessation of the CSF leak are uncertain. 3. Antibiotics may promote growth of resistant strains of organisms within the nasopharynx and consequently lead to infection with resistant or unusual organisms.75
preferred nonvascularised graft due to angiogenic factors that can aid recruitment of the surrounding blood vessels. Fat also has a low metabolic requirement, resisting necrosis and scarring.59 Muscle can undergo fibrosis and atrophy resulting in graft failure.60 Other nonvascularised grafts such as harvested temporalis fascia and fascia lata are commonly used. Autologous bone graft can be harvested from the vomer, split calvarium, iliac crest or rib and cartilage grafts can be harvested from septal or auricular cartilage. Allograft materials such as absorbable gelatin sponge, oxidised cellulose haemostat, fibrin, collagen and acellular dermal allograft are sometimes used to facilitate repair. Processed whole-tissue xenografts such as bovine pericardium have been used for duraplasty for many years. They are strong, pliable, easy to handle and relatively cheap. However, they require watertight suturing and are at risk of causing foreign body reactions, aseptic meningitis and, depending upon source, potentially the transmission of Creutzfeldt–Jacob Disease. To overcome some of these shortcomings, engineered collagen-matrices have been developed. A study by Prickett et al.61 has shown that all three (mucosal grafts, acellular dermis and collagen matrices) graft types have similar success rates in endoscopic repair of CSF leaks. Inorganic implants, including both titanium mesh and porous polyethylene implants, are used for reconstruction of soft tissue and bony defects. Cranioplasty cements such as polymethylmethacrylate and hydroxyapatite do not provide a watertight seal and can predispose patients to delayed infections by entrapping microbes, with an infection rate of 3–20%, compared with 0–11% for autologous bone.62
Transverse Fractures.—Transverse fractures usually result from occipital impact. They traverse perpendicular to the long axis of the petrous bone and extend toward the jugular foramen and temporal fossa
Traumatic CSF leakage due to temporal bone fracture occurs four times more commonly with otic capsule–violating fractures than with otic capsule–sparing fractures (5) and is more common with longitudinal fractures than with transverse fractures (14).
