Journal club

CEREBROSPINAL FLUID: IMPLICATIONS IN ORAL AND MAXILLOFACIAL SURGERY

M. Todd Brandt, W. Scott Jenkins, Tirbod T Fattahi, Richard H Haug.JOMS 2002; 60: 1049-1056.

Introduction CSF is an essential component of the nervous

system. Serves as cushion, lubrication for cerebral

hemisphere and meningeal layer. CSF fistula and leaks are documented in variety

situation trauma, skull base surgery, functional endoscopy, spontaneous.

Galen in 2nd century AD, first documented the description of CSF fistula(rhinorrhea)

First correlation of CSF rhinorrhea with craniomaxillary trauma was made in 17th century by Bidloo & Elder.

CSF fistula is serious potential fetal condition, successful management requires through understanding of pertinent anatomy & path physiology.

This article reviews the anatomy & path physiology of CSF , clinical significance of CSF fistula , highlights on etiology and management of CSF leaks seen in OMFS.

Anatomy

CSF is formed in the choroid plexus around the lateral ventricle and lesser amount by 3rd & 4th ventricle. Partly by arachnoid villi with rate of 0.35-0.40ml/min.

Choroid plexusLateral

ventricle Third

ventricle Forth

ventricle

Circulation & absorption of

CSF

Lateral ventricles

Intra ventricular foraminaMonroe foramina

3rd ventricles

Cerebral aqueduct of midbrain

4th ventricles

Tentorial notch

Inferior surface of cerebrum

Superolateral surface of cerebrum

Arachoid granulations

Superior sagittal sinus

Central canal of spinal cord

Subarachnoid space around spinal cord & cauda equina

Veins of spinal cord

Foramina MagendieForamina Luschka

Sub arachinoid space

laterally

medially

Cerebrospinal Fluid Circulation.flv

Physiology CSF termed as third circulation. Clear fluid bathing the brain & meninges produced

on daily basis in ventriculocisternal portion of nervous system.

In adult avg intracranial volume is 1700ml, CSF makes about 5-10% volume (50-160 ml).

Rate of formation is 20-22ml/hr or 500ml/day or 0.35-0.40 ml/min.

CSF as a whole is renewed 4-5 times a day. In recumbent position intra cranial pressure is 8-12

mm Hg or 110-150 mm H2O (ie equilibrium to capillary pressure)

Autoregulation maintains the intracranial pressure irrespective of ↑ arterial pressure.

Co2 has profound effect on the CSF pressure. Hyperventilation: rapid ↓ in Pco2, ↑ pH & ↓

the CSF pressure.

Function of CSF:1. Serves as water cushion for brain & spinal

cord protect from blunt force trauma.

2. Provides the media to support the nervous system in closed bony cavity and protect by countercoup mechanism.

3. No lymphatic channels in nervous system , serves to remove the cerebral metabolic waste.

4. Active transport & passive diffusion allows exchange of electrolyte and fluid between plasma & extracellular space around choroid cell.

Various constituent of CSF.

Constituents CSF Serum Nasal secretion

Osmolarity (mOsm/L)

295 295 277

Na (mEQ/L) 140 140 150

K (mEQ/L) 2.5-3.5 3.3-4.8 12-41

Cl (mEQ/L) 120-130 100-106 119-125

Glucose (mg/100ml) 58-90 80-120 14-32

Albumine (of total protein)

50-75% 55% 57%

Total protein (mg/dL) 5-45 6-8.4 335-636

IgG (mg/100ml) 3.5 1140 51

B2 Transferrin 15 0 0

Incidence of CSF leak

CSF not common in all the trauma. Reports suggests 80% CSF leaks are direct results of

trauma ( craniomaxillary trauma- naso-orbito-ethmoidal #, postrior table frontal sinus #, skull base #)

closed head injury with basilar skull # and CSF leaks range from 2%-30%.

16% occurs secondary to surgery (iatorgenic nasal, paranasal, skull base surgery, functional endoscopic procedure)

remaining 4% spontaneous in origin(hydrocephalus, brain tumor, congenital anomaly)

Pediatric population presents with lower CSF leaks as facial skeletal development not reached the maturation & sinus pneumatization is incomplete,

Patho-physiology

It presents as CSF Rhinorrhea or CSF otorrhea.

most of times, occurs through anterior cranial fossa as at this region dura is tightly adhered to thin bone of cribriform plate and roof of ethmoid.

factors affecting nature of leak- Disruption of arachinoid & dura laceration,

tear in periosteum & mucosa. Degree of displacement of bony

fragments. Intracranial pressure Increased production of CSF

Classification

Ommaya classification system for CSF leak (1964)

Traumatic (80-90%) Non-traumatic (10-20%)

Accidental (Cranimaxillofacial fractures)

High pressure leaks1. Tumors2. Hydrocephalous3. Benign intracranial

hypertension

Iatrogenic (neurosurgical & functional endoscopic procedures)

Normal pressure leaks1. Congenital anomaly2. Focal atrophy3. Osteomyelitic erosion

Evaluation Clinical presentation

Clinical/Laboratory identification

Imaging

1. Otorrhea (25%), rhinorrhea (68%)

2. High suspicious with epistasis, pharyngorrhea, hemotympanum , battels sign, post traumatic serous otitis media.

3. CSF leaks should be assumed until ruled out.

Clinical-1) Reservoir sign2) Target sign (ring test)3) Altered ICP causes

headaches.4) Low pressure- headache

to be relieved by staining or performing Valsalva movement .

5) High pressure- headache relieved by release of CSF eg lumbar puncture

Laboratory-6) Glucose CSF conce ≥

plasma7) ↓Protein & K+ level8) β2 transferrin

1) Plane radiographs , CT scans: disruption of bony architecture, air or fluid level, tumor masses.

2) Cysternography :a. non radioactive dyes- Methylene blue,

phenol sulfonphthalein, flurescin.

b. Radioactive agent- Indium 11diethyleen

triaminic penta acetic acid (DPTA), technetium 99m-DPTA.

c. Combination of imaging along with contract medium (metrizamide)

Clinical management-

Conservative medical approach

Surgical intervention

Conservative medical approach Strict bed rest Head elevation 35 ° -45° Instruction to avoid activity that ↑ ICP

(coughing, nose blowing, sneezing, straining) Stool softener Acetazolamide (↓ CSF production ) Incidence of meningitis is 3%-50% and

mortality associated with post traumatic meningitis is 10%

Antibiotic prophylaxis is not recommended Clemenza et al

Protocol for surgical intervention Spontaneous closure of CSF fistulas within 48 hrs =

68%, 1 week = 85%. With reduction of craniofacial fracture CSF leaks

resolve spontaneously During reduction any suspicion regarding posterior

frontal table, orbito-ethmoidal #, fistulas are obliterated with galeal flap or fat.

If conservative management of facial # to slow the leak with 72 hr, lumbar subarachnoid drain placed ( if no indication for craniotomy)

Persistent leak > 8days despite of subarachnoid lumbar drain, craniotomy is require to repair the CSF fistula.

Surgery can be performed extra cranially ( endoscopic or transfacial) intracranially (craniotomy)

Patient selection for surgical repair Complication of CSF fistula – tension meningitis,

pneumocele. ↓ Incidence of meningitis (9%), {post traumatic

meningitis organism asso. Pneumococcous species} Repair of basal dural tear can prevent meningitis

(Teasdaie & Jennett) Classification of compound skull fracture by Sakas et al

I- Cribiform II- Fronto-ethmoidal III- lateral frontal IV- complex(any combiantion of above).

Type I are more prone fro infection than type II & III (near to sagittal midline are prone for infection)

Large fracture with max bone displacement (> 1 cm any plane .

Patient with transient rhinorrhea >8 days high risk of meningitis.

A. Lumbar drain- First indwelling catheter was reported in

1963. these are subarachnoid lumbar drain

effectively reduce the hydrostatic pressure.

Drains are kept for 4-10 days, drains CSF about 150 ml /day.

Risk of meningitis ↑ up to 10% when lumbar drains violate the subarachnoid space.

procedure may also present with complications like transient lumbar nerve root irritation, CSF overdraining leading temporary neurological decline.

B. Intracrainal repair- Dandy 1926, first described intracranial repair of

CSF fistula. Craniotomy

Advantage- Direct visualization of dural tear. Allows inspection of adjacent t brain injury Preferred when extracranial approach has failed.

Disadvantage- Asomia Intracranial hemorrahge Brain edema Skull base exposure Brain retraction

C. Extracranial repair- Dohlman 1948, first extra cranial approach

for CSF fistula repair. Appproaches- External ehtmoid-sphenoidal (medial

orbital incision, dissect orbital content posteriorly to gain ethmoidal labyrinth, fistula repair can be done with fascial late, muscle, fibrin glue)

Transmastoid (with high speed bur mastoid air cells are removed)

Transseptosphenoidal (trans nasal route),

D. Endoscopic repair Overall success 98%, Can address ethmoidal roof, cribiform

plate, sphenoidal defects Recommended when defect is < 1 cm.Disadvantage- Limited visualization Possible cerebral damage.

Post operative care

Patient going for the surgical repair shunts are kept at adjacent to direct repair

Shunts are kept appro 4-10 days Antibiotic prophylaxis for the patient with

higher risk of meningitis, preexisting sinusitis, compound skull base fracture with gross contamination.

Nafcillin, gentamicin, cephazolin excellent choice.

Surgical pack with antibiotic is kept to reduce bacterial endotoxin.

Thank you…