Lumbar Puncture What you need to know (and what I wish I had )

2. Lumbar PunctureWhat you need to know (and what I wish I had) Mark Keezer, MDCM, FRCPC MSc candidate, Epidemiology, McGill University Epilepsy Fellow, National Hospital for Neurology & Neurosurgery, London, UK (to begin in September, 2013)

4. NEJM video http://www.nejm.org.proxy1.library.mcgill.ca/doi/full/10.1056/NEJMvcm054952

5. Outline • Preparation • The Procedure • Interpreting the Results • PLPHA

6. 1. Preparation Consent Antiplatelets Labs Neuro-imaging Supplies needed

7. Patient consent • Back pain • Radicular pain • Hemorrhage • Infection • PLPHA (~40%)

8. Should antiplatelets or prophylactic heparin be held?

9. Prospective cohort • 924 orthopedic patients undergoing spinal or epidural anesthesia • 39% receiving antiplatelets • 2% receiving prophylactic heparin • 0 epidural hematomas • No relationship with minor hemorrhage during procedure Horlocker TT et al. Preoperative antiplatelet therapy does not increase the risk of spinal hematoma associated with regional anesthesia. AnesthAnalg 1995;80:303-9.

10. Risk of epidural hematoma with clopidogrel unknown

11. What are the minimum platelet count and INR values?

12. Coags& platelets • Platelets > 50,000 • INR <1.5 • Guidelines at the Preston Robb day centre • Currently it seems it is acceptable to not verify CBC and coags if patient reasonably expected not to have any abnormalities (verbal communication with Dr. Durcan).

13. Prospective cohort 301 patients • Risk factors for CT head abnormality • >60 yo • Immunocompromised • Hx of CNS disease • Hx of seizure within 1 wk • Abnormal neurologic exam • Including poor comprehension • Sensitivity 94% • Specificity 51% HasbunR et al. Computed Tomography of the head before lumbar puncture in adults with suspected meningitis. NEJM 2001;345:1727-33.

14. The LP kit

15. What else do you need? • The obvious • Xylocaine • 1% or 2% • With or without epi • Topical disinfectant • 5% chlorhexidine (avoid detergent and 0.5% solution) • Proviodine solution • The essential • Sterile gloves • Face mask • The helpful • Piquet • Keep your RN happy • 2 Pillows

16. CSF tubes • How many tubes do you need? • How much CSF in each tube? • 1 cc • For most standard tests • 2 cc • HSV PCR • OCB (don’t forget to send serum!) • 3 cc • Cytology • 8 cc • AFB cultures • Fungal cultures

17. Local anesthesia • Max xylocainedose (70 kg individual) • 30cc if 1% • 15cc if 2% • s/c needle alone vs additional 20 gauge needle • The “bleb”

18. 2. The Procedure Positioning Vertebral level

19. Positioning • Back as close to edge of bed as possible • Maximize anteroflexion • Minimize lateroflexion • Pillow under head & between legs • Be careful of the shoulders • Palpate along the vertebral bodies

20. Tuffier’s line

22. Vertebral level • L3-L4 vs L4-L5 • Compromise between width of the space and spondylosis • Conusmedullaris extends to L2-L3 in 6% of pts

23. The Procedure • Aim towards the umbilicus • The expected resistance of the interspinousligament • The satisfying “pop” of the ligamentumflavum

24. The stylet • Never move the needle without the stylet! • With insertion of the needle • Avoid introduction of a plug of epidermis into the subarachnoid space, allowing for the growth of an epidermoid tumour • With removal of the needle • Prevent a strand of arachnoid being threaded into the dural defect, increasing risk of PLPHA

25. If not in the proper space • Most often needle is deviated from the midline • Hence the radicular pain • Attempt with large gauge needle (18 or 20 gauge) • If no CSF • Rotate the needle 90° • Advance further or withdraw • If slow flow • Valsalvamanoeuvres • Throw out any bloody needle

26. Negative pressure LP • Has been studied and found to be safe • Only while using 25 gauge needles or smaller! Linker G et al. Fine-needle, negative-pressure lumbar puncture: a safe technique for collecting CSF. Neurology 2002;59:2008–2009.

27. 3. Interpreting the Results Normal values Tubes 1 & 4 Correcting for a traumatic tap

28. Normal CSF values • ≤ 5 RBC / μL • ≤ 5 WBC / μL • Protein • ≤ 0.5 gr/L • Cytology • 80% sensitive for leptomeningeal carcinomatosis from lymphoma or leukemia.

29. 123 patients with suspected SAH • 8 patients with ruptured aneurysm on CA but negative CT head • 2 patients had a > 25% in RBC count between tubes #1 and #4

30. Correcting WBC in a traumatic tap • RBC x (peripheral blood WBC count ÷ peripheral blood RBC count) • Usually ~ 1000

31. Correcting protein in a traumatic tap • Add 0.01 gr/L for every 1000 RBC / μL

32. 4. PLPHA Proven methods to decrease risk Unproven methods Treatment

34. What can we do to prevent PLPHA?

35. PLPHA prevention • Proven methods • Bevel parallel to spine • Atraumatic needle • Needle gauge • Unproven • Recumbency • Volume of CSF removed

36. Systematic review of the literature • Atraumatic needle superior to Quincke • 24% versus 12% • Small gauge superior to large gauge

37. Needle types } “atraumatic” needles

38. Prospective cohort 239 patients • Sex • Women = 46%; men = 21% • Gauge • 20 gauge = 50%; 22 gauge = 26% VilmingST et al. The importance of sex, age, needle size, height and body mass index in post-lumbar puncture headache. Cephalalgia2001;21:738–743.

39. Bevel orientation • Prospective cohort of 380 patients • Bevel parallel to spine (bevel up) • 7.9% with PLPHA • Bevel perpendicular to spine • 19.3% with PLPHA Kochanowicz J et al. Post lumbar puncture syndrome and the manner of needle insertion [in Polish]. NeurolNeurochir Pol 1999;32(suppl 6):179–182.

40. Post LP recumbency has been studied by several studies, none of which have shown any clear benefit (up to 24 hrs) • Most clinicians will generally enforce some period • Dr. Bray’s 45 minutes

41. Treatment of PLPHA

42. Epidural blood patch • 15-20 cc autologous blood • At site of LP • Supine 1-2 hrs post • 95% reported success rate

43. Summary • Preparation • Don’t hold the ASA • CBC, coags and neuro-imaging? • Plan your CSF tubes • The Procedure • Positioning! • The stylet • Interpreting the Results • Be concientious about Tubes 1 & 4 • Correcting for a traumatic tap • PLPHA • Prevention • Bevel parallel to spine • Atraumatic needle • Needle gauge • Treatment

44. Questions?