Chemical Neurolytic - PowerPoint Presentation

1. Chemical Neurolytic Agents Dr S. Parthasarathy MD DA DNB PhD FICA , Dip software based statistics

2. Prolonged pain – we want prolonged block of nerve conduction Prolonged interruption of painful pathways may be accomplished by injection of neurolytic agentsNeurolysis – lysis of nerve fibres

3. Methods Chemical Neurolytic BlocksCryoablative TechniquesRadiofrequency LesioningNeurosurgical ProceduresChemical

4. When to administer Severe unbearable pain Routine noninvasive methods are not much useful Localized to a nerve location Diagnostic block is clinching No obvious side effects is shown Counseling with patients and attendants

5. Indications 1. chronic, intractable, non-terminal pain that are not responsive to other modalities2. cancer pain in those patients who have short life expectancy (less than a year); 3. Alternative management to treat spasticity in order to improve balance, gait, self-care, and global rehabilitation1 and 2 – predominant sensory 3 – predominant motor

6. Chemical agents Alcohol Phenol Hypertonic saline Ammonium salts Butamben Chlorocresol

7. Spinal neurolytic techniquesNeurolytic saddle blockPhenol epidural blockCeliac plexus blockNeurolytic lumbar sympathetic blockNeurolytic peripheral nerve blocksLocal neurolytic injection

8. Classification Peripheral - Neuraxial -Visceral problem of motor block bowel bladder functionsPresence of neuraxial morphine and clonidineCommonest use

9. Alcohol degeneration and absorption of all the components of the nerve except the neurilemmaMotor sensory and autonomic affected Alcohol extracts phospholipids, cholesterol and cerebroside from neural tissues and precipitates mucoprotein and lipoprotein

10. Burning pain on injection the patient complains of severe burning pain along the nerve's distribution which may last for a minute and is subsequently replaced by a warm, numb sensation.Advised to add local as diluent

11. Alcohol 33 % minimal 95 % - maximal Usually 50 -90 % Hypobaric 0.3 – 0.7 ml / segment Position accordingly

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13. Find out the segment Confirm with image intensifier if necessARY INJECT LOCAL CONFIRM THE ACTION SITE Then

14. Using a 1-mL syringe, the alcohol is injected in 0.1-mL increments, with at least 60 to 90 seconds between repeat administrations.The maximum dose per nerve is usually 0.3 mL and the total alcohol volume should not exceed 0.5 to 0.7 mL when several nerve roots are neurolyzed.After injection, the patient should remain in the same position for 15 to 30 minutes.

15. Phenol Phenol is a chemical composite containing carbolic acid, phenic acid, phenylic acid, phenyl hydroxide, hydroxybenzene, and oxybenzene6-7 % Water or glycerol

16. Water more potent and wider spread Glycerol – less potent and less wide spread Think of our targets

17. Phenol has systemic side effects including central nervous system stimulation, cardiovascular depression, nausea, and vomiting. Systemic doses of more than 5 grams can cause seizures and central nervous system depression. Doses less than 100 mg are less likely to cause serious side effects.

18. 6 % = 60 mg / ml 10 ml is only 600 mg 5 grams is the most dangerous zone

19. How it destroys nerve Phenol causes nerve destruction by inducing protein precipitation. loss of cellular fatty elements, separation of the myelin sheath from the axon, axonal edema. .

20. phenol is not as effective as alcohol at destroying the nerve cell body blocking effect tends to be less profound shorter duration than alcohol

21. At a concentration of 2-3 percent in saline, phenol seems to spare motor function. 3% phenol = 40 % alcohol It has an immediate local anesthetic effect due to its immediate selective effect on smaller nerve fibersIrritation – initial ?? Preparations of phenol in glycerin are highly viscous, which may make administration through a small (22 or 25 gauge) spinal needle difficult

22. Phenol can be injected intrathecally and epidurally. Phenol in glycerol is hyperbaric compared to the CSF. Position in case of intrathecal use ?? It can be used also for paravertebral somatic block, peripheral nerve blocks, and sympathetic blocks.

23. Phenol turns red on exposure to sunlight and air because of oxidation. It is metabolized in the liver by conjugation to glucuronides and oxidation to equinol compounds or to carbon dioxide and water

24. Technique Site and block quantity of drug After sterile precautions – depending on the technique of finding the plexus Administer the desired volume intercostal – 4 -5 ml – means 7 % phenol 4 ml + 1 ml glycerol Or absolute alcohol 3 ml + saline 2 or 3 ml

25. block cannot be evaluated until after 24-48 hours, Allow time for the local anesthetic effect to dissipate. The neurolytic effect may be clinically evident only after 3 to 7 days.inadequate pain relief in two weeks, incomplete neurolysis and requires repetition of the procedure.

26. Don’t assess immediate

27. If nerve cell body is gone , regeneration is difficult sprouting may occur to regenerate 1 – 3 mm/day with arborization in one or two months to cause neuropathic pain

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29. Hypertonic saline The use of hypertonic saline by intrathecal injection to treat intractable pain was first reported by Hitchcock in 1967. The most commonly used solution is the 10 percent aqueous solution and is available as a pharmaceutical preparationMechanism of neurolysis – not known

30. Others Cold saline 2 - 4 degrees 40 – 60 ml used with local anesthetics Glycerol – tic doulerex No permanent injury More useful in damaged axons Ammonium salts SO4,Cl >10% - degeneration

31. In the uninjured nerve, the c-fiber and lightly myelinated fibers are the most sensitive to neurolysis, requiring higher concentrations to destroy the heavily myelinated fibers. However, this order is altered in the injured nerve;the heavily myelinated fibers become very sensitive to the neurolytic properties of glycerol.

32. Complications of neurolysis Each block – separate complications Eg. Artery of adamkewicz – spasm General Skin and other non-target tissue necrosis and sloughing: This is due to damage of the vascular supply to the skin, causing ischemia,

33. Site – differs

34. Neuritis:The reported incidence up to 10 percent. caused by partial destruction of somatic nerve and subsequent regeneration. nerve cell body is not destroyed. less likely with a subarachnoid or ganglion neurolytic block. It is clinically manifested as hyperesthesia and dysesthesia that may be worse than the original pain.

35. Anesthesia DolorosaPain with no sensation CNS changes ? Trial of local anesthetics and check Treat with TCADs

36. Prolonged motor paralysisMay be frequent But settles in a few months

37. Perineal and sexual dysfunctionAbout 1.4 percent and 0.2 percent of patients will have bowel or bladder dysfunction at one week and one month, respectively.Systemic complications like bradycardia, hypotension rhythm disturbances, excitement

38. Spasticity Examples of these blocks include obturator block to relieve hip adduction, musculocutaneous nerve block for elbow flexion, posterior tibial nerve block for plantar flexion

39. Target the motor component Use nerve stimulator Get the desired effect Use alcohol

40. Neurolytic injections have been reported to be useful in patients with palpable painful neuromas (0.2 to 0.5 mL of 5% phenol) patients with post sternotomy pain secondary to scar neuroma (2 to 3 mL of 6% phenol), patients with painful surgical scars (1 mL of absolute alcohol)Rare – 10 ml of 10 % phenol brachial plexus for pancoast tumour

41. Other Cryo probe Extremely low temperature Radiofrequency – em field – electrical current – dissipates heat – destroys nerves

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43. Ablative procedures NeurectomyCranial neurectomyPeripheral neurectomySympathectomyCordotomyCommissurotomyMesencephalotomyThalamotomyCingulotomy

44. Summary Indication Clinical scenarioDrugs Usage Complications

45. Thank you all