1. CSF Leaks Steven Wright, M.D. Matthew Ryan, M.D. January 5, 2004

2. CSF Leaks  Abnormal communication between the subarachnoid space and the tympanomastoid space or nasal cavity.  Presenting symptoms: Middle ear effusion, hearing loss Middle ear effusion, hearing loss Unilateral rhinorrhea Unilateral rhinorrhea  Risk of meningitis is high 2-88% 2-88%

3. CSF Rhinorrhea  Diverse etiology IdiopathicTrauma-Surgical<1%Trauma-Nonsurgical 3% of all closed head injuries 30% of skull base fractures Frontal>Ethmoids>SphenoidsInflammatoryCongenitalNeoplasm

4. Testing of Nasal Secretions  Beta-2-transferrin is highly sensitive and specific 1/50 th of a drop 1/50 th of a drop  Electronic nose has shown early success

5. Imaging  High resolution CT  CT Cisternography  MRI Heavily weighted T2 Heavily weighted T2 Slow flow MRI Slow flow MRI MRI cisternography MRI cisternography  Radionuclide cisternography  Intrathecal flourescin

6. Imaging  HRCT Volume averaging Volume averaging Congenital dehiscences of Spenoid/cribiform niche. Congenital dehiscences of Spenoid/cribiform niche.

7. Imaging  CT cisternography Currently the optimal imaging modality (85% sensitive) Currently the optimal imaging modality (85% sensitive) Intrathecal administration of iodine, prone 6hrs Intrathecal administration of iodine, prone 6hrs 0% for inactive leaks 0% for inactive leaks Substantial radiation exposure Substantial radiation exposure ?neurotoxic potential ?neurotoxic potential

8. Imaging  MRI cisternography heavily weighted T2 heavily weighted T2  Intrathecal gadolinium

9. Imaging  Slow flow MRI  Diffusion weighted MRI  Fluid motion down to 0.5mm/sec  Ex. MRA/MRV

10. Imaging  Radioisotope cisternography Intrathecal administration of technitium 99m Intrathecal administration of technitium 99m Less spatial resolution and specificity Less spatial resolution and specificity Largely abandoned due to false positive and false negative results Largely abandoned due to false positive and false negative results

11. Intrathecal Flourescin  0.1ml of 10% flourescin solution mixed in 10cc of CSF  Blue light may enhance the flourescin  Complications are low

12. Treatment of CSF Rhinorrhea  Conservative measures Bed rest/Elev HOB>30 Bed rest/Elev HOB>30 Stool softeners Stool softeners No sneezing/coughing No sneezing/coughing +/- lumbar drains +/- lumbar drains  Early failures Assoc with hydrocephalus Assoc with hydrocephalus Recurrent or persistent leaks Recurrent or persistent leaks

13. Treatment of CSF Rhinorrhea  Prophylactic antibiotics: Two conflicting meta-analysis regarding basilar skull fractures. Two conflicting meta-analysis regarding basilar skull fractures. Proponents argue less meningitis. Proponents argue less meningitis. Opponents argue organism resistance. Opponents argue organism resistance.

14. Surgical Options  Intracranial Direct visualization Direct visualization Success rates 50-73% Success rates 50-73% Significant morbidity Significant morbidity AnosmiaAnosmia Cerebral edemaCerebral edema SeizuresSeizures

15. Surgical Options  Extracranial approach Improved success rates (80%) Improved success rates (80%) Significant morbidity Significant morbidity Frontal osteoplastic flap/infratemporal approach Frontal osteoplastic flap/infratemporal approach

16. Endoscopic repair  Endoscopic intranasal repair Overall success rates: Overall success rates: 90% 1st attempt90% 1st attempt 52-67% for 2 nd attempt52-67% for 2 nd attempt Overall 97%Overall 97% Complications: Complications: Meningitis (0.3%)Meningitis (0.3%) Brain abscess (0.9%)Brain abscess (0.9%) Subdural hematoma (0.3%)Subdural hematoma (0.3%) Headache (0.3%)Headache (0.3%)

17. Endoscopic techniques

18. Overlay vs Underlay technique  Meta-analysis showed that both techniques have similar success rates  Onlay: adjacent structures at risk, or if the underlay is not possible

19. Surgical Techniques  Use gelfoam and gelfilm (>90%)  Use nasal packing (100%)  Consider fibrin glue (>50%)  Consider lumbar drain for idiopathathic/posttraumatic assoc with increased ICP 3-5 days 3-5 days Not required Not required  BR, stool softeners, antibiotics

20. CSF Otorrhea  Acquired Postoperative (58%) Postoperative (58%) Trauma (32%) Trauma (32%) Nontraumatic (11%) Nontraumatic (11%)  Spontaneous Bony defect theory Bony defect theory Arachnoid granulation theory Arachnoid granulation theory

21. Temporal bone fractures  Longitudinal 70% 70% Anterior to otic capsule Anterior to otic capsule 15-20% facial nerve involvement 15-20% facial nerve involvement

22. Temporal bone fractures  Transverse 20% 20% High rate of SNHL High rate of SNHL 50% facial nerve involvement 50% facial nerve involvement

23. Temporal bone fractures  HRCT will demonstrate the fracture line and the likely site of CSF leak.  Beta-2-transferrin  Treatment Bedrest Bedrest Elev HOB Elev HOB Stool softeners Stool softeners +/- lumbar drain +/- lumbar drain

24. Temporal bone fractures  Brodie and Thompson et al.  820 T-bone fractures/122 CSF leaks  Spontaneous resolution 95/122: within 7 days 95/122: within 7 days 21/122: between 7-14 days 21/122: between 7-14 days 5/122: Persisted beyond 2 weeks 5/122: Persisted beyond 2 weeks

25. Temporal bone fractures  Meningitis 9/121 (7%) developed meningitis. 9/121 (7%) developed meningitis.  A later meta-analysis by the same author did reveal a statistically significant reduction in the incidence of meningitis with the use of prophylactic antibiotics.

26. Pediatric temporal bone fractures  Much lower incidence (10:1, adult:pedi) Undeveloped sinuses, skull flexibility Undeveloped sinuses, skull flexibility  otorrhea>> rhinorrhea  Prophylactic antibiotics did not influence the development of meningitis.

27. Spontaneous CSF otorrhea  Congenital Defect Theory: 1) enlarged petrosal fallopian canal 1) enlarged petrosal fallopian canal 2) patent tympanomeningeal (Hyrtl’s) fissure 2) patent tympanomeningeal (Hyrtl’s) fissure 3) Comminication of the IAC with the vestibule (Mondini’s dysplasia)-most common 3) Comminication of the IAC with the vestibule (Mondini’s dysplasia)-most common  Childhood presentation 82% SNHL 82% SNHL 93% Meningitis 93% Meningitis 83% Mondini Dysplasia 83% Mondini Dysplasia

28. Congenital bony defect

29. Spontaneous CSF otorrhea  Arachnoid granulation theory Enlargement of arachnoid villi due to congenital entrapments/pressure variations Enlargement of arachnoid villi due to congenital entrapments/pressure variations  Presentation Unilateral serous otitis media Unilateral serous otitis media Meningitis (36%) Meningitis (36%) No SNHL or Mondini dysplasia No SNHL or Mondini dysplasia Sites are multiple, floor of the middle fossa most common Sites are multiple, floor of the middle fossa most common

30. Arachnoid Granulation

31. Spontaneous CSF otorrhea  Stone et al.  HRCT vs. CT cisternography/radionuclide cisternography. HRCT showed bony defects in 71%. HRCT showed bony defects in 71%. 100% intraoperative findings correlated with HRCT. 100% intraoperative findings correlated with HRCT. HRCT significantly identified more patients with CSF leak than radionuclide cisternography or CT cisternography. HRCT significantly identified more patients with CSF leak than radionuclide cisternography or CT cisternography.

32. Surgical approaches  Transmastoid Not ideal for large defects (>2cm), multiple defects, or defects that extend anteriorly Not ideal for large defects (>2cm), multiple defects, or defects that extend anteriorly  Middle cranial fossa Technically challenging Technically challenging Best exposure Best exposure  Combined approach

33. Technique of closure  Muscle, fascia, fat, bone wax, etc..  The success rate is significantly higher for those patients who undergo primary closure with a multi-layer technique versus those patients who only get single-layer closure.  Refractory cases may require closure of the EAC and obliteration.

34. Conclusions  The clinical presentations of CSF leaks may be very subtle.  The clinician must keep a low threshold for further testing with Beta-2-Transferrin.  Imaging studies should be performed to anatomically localize the site.  Success rates may be over 90% with proper patient and surgical selection