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Trigeminal Neuralgia.pptx
- 1. Trigeminal Neuralgia Department of Neurosurgery Dr RE Anto 22/02/2023
- 2. Contents • History • Epidemiology • Anatomy • Etiology • Pathophysiology • Diagnosis • Differentials • Nonsurgical management • Surgical management
- 3. History • Aretaeus of Cappadocia (2nd Century) • Ancient Greek Physician • Fothergill (1773) • First adequate clinical description • Synonyms • Tic Douloureux • Fothergill’s disease
- 4. Trigeminal Neuralgia • Most common neuralgia! • Most excruciating pain syndromes • Can drive patients to suicide • Characteristics: • Paroxysmal, sharp electric-like lancinating pain • Periods of remission • Initial response to Carbamazepine • Neurological exam must be intact!
- 5. Epidemiology • Incidence 4/100 000 • Slight female predominance (1.8:1) • Age peaks > 5th decade • Younger patients: Suspect demyelinating disease
- 6. Anatomy • Largest cranial nerve • Three sensory nuclei • One motor nucleus • Three branches • Ophthalmic (V1) • Maxillary (V2) • Mandibular (V3)
- 7. Gray’s Anatomy, 40th ed., Standring, Infratemporal and pterygopalatine fossae and temporomandibular joint, p. 545, Image B, Copyright Elsevier, 2008.
- 8. Etiology • Idiopathic • Usually from pulsations of an aberrant vascular loop • Most commonly: Superior cerebellar artery (80%) • Anterior inferior cerebellar artery • Less commonly: Vein • Secondary • Tumours near Gasserion Ganglion • Multiple Sclerosis (plaques)
- 10. International Headache Society (2004) • Recurrent, sharp lancinating pain lasting 10-30 sec • Paroxysmal attacks • Followed by a refractory period • Confined to an area innervated by the TN • Triggered by non-noxious stimuli • Chewing, shaving, eating, cold air on face, light touch, talking • No neurological deficit
- 11. Diagnosis • History! • Imaging: To rule out any other secondary causes • MRI • Coronal 3D TOF MRA – centred on vertebro-basilar system • Superimpose that on the Spin echo T1 – show cisternal portions of the 5th nerve • CISS • Blood workup (normal)
- 12. Differential Diagnosis • Atypical facial pain sx • Cluster headache • Postherpetic neuralgia • Geniculate neuralgia • Dental disease • Temporomandibular dysfunction • Temporal arteritis
- 13. Nonsurgical Management • Anticonvulsants as first line • Carbamezapine (most effective) • Only FDA approved medication • > 75% patients will respond • Start gradually (100mg bd) • Titrate upwards according to response • Max dose 1200mg per day
- 14. Nonsurgical Management • Oxcarbazepine • Gabapentin • Pregabalin • Baclofen • Lamotrigine • Phenytoin (IV if acute severe attack)
- 15. Surgical Management • Microvascular decompression • Rhizotomy • Glycerol • Radiofrequency • Compression balloon • Gamma knife radiosurgery
- 17. Microvascular Decompression • JANNETTA PROCEDURE • Most effective surgical procedure • Addresses the etiology directly • Younger, healthier patients • Retro-sigmoid craniotomy
- 19. Percutaneous Glycerol Rhizotomy • Percutaneous Retrogasserian glycerol rhizotomy • Hakanson (1981) • Inject a needle into Meckels cave • Fluroscopy
- 20. Hartel Technique • Inject sterile anhydrous glycerol into trigeminal cistern • Up to 0.5ml • Burning sensation, flushing, supra- orbital pain
- 21. Radiofrequency Thermocoagulation • Introduced by Sweet (1965) + altered by Tew (1982) • Selectively injures the unmyelinated nociceptive fibers • A-delta + C-fiber nociceptors • Spares the heavily myelinated fibers • A-alpha + A-beta • Serve touch, proprioception and motor
- 23. Percutaneous Balloon Compression • Originally described by Muller and Lichter • 4F Fogarty balloon catheter • Inflate balloon with 0.3 – 0.8 ml of iohexol • Pear-shaped balloon “Meckel’s cave” • Hold pressure for 1-6 min
- 24. Gamma Knife Radiosurgery • Least invasive procedure • Poor surgical candidates • Radiation aimed at proximal root + REZ • Single dose of 86 (75-90) Gy at 100% isodose (or 43 Gy at 50% isodose) to trigeminal root • Pain relief is not immediate
- 25. Modalities Mohammad-Mohammadi, Alireza “Surgical Outcomes of Trigeminal Neuralgia”, Neurosurgery: December 2013 - Volume 73 - Issue 6 - p 941–95
- 26. Conclusion • Take a good history • Make sure to rule out underlying secondary causes! • Determine appropriate management strategy as per the individual patient • All the options
- 27. References • Bowsher, D., 1997. Trigeminal neuralgia: An anatomically oriented review. Clinical Anatomy 10 (6), 409–415. • Burchiel, K., Baumann, T., 2004. Pathophysiology of trigeminal neuralgia: New evidence from a trigeminal ganglion intraoperative microneurographic recording. Case report. Journal of Neurosurgery 101 (5), 872–873. • Prasad, S., Galetta, S., 2007. The trigeminal nerve. In: Goetz, C. (Ed.), Textbook of clinical neurology. Saunders Elsevier, Philadelphia, pp. 165– 183. • GreenBerg, Handbook of Neurosurgery 9th edition
- 28. Question 1 Trigeminal neuralgia is most commonly caused by which one of the following: A. CP angle tumour B. Multiple sclerosis plaque at the root entry zone of the trigeminal nerve C. Compression by superior cerebellar artery D. Compression by superior petrosal vein
- 29. Question 2 The pain associated with trigeminal neuralgia can sometimes be misdiagnosed as other pain syndromes. Which of the following are quite characteristic of trigeminal neuralgia: A. Long standing dull facial pain B. Paroxysmal sharp pain lasting less than 2 minutes C. Motor neurological fallout of the mandibular division (V3) D. Pain associated with an aura
- 30. Question 3 A 42 year old female patient with no known comorbidities and otherwise quite healthy, comes to you diagnosed with features quite typical of trigeminal neuralgia. Which of the following is the first line drug of choice: A. Baclofen B. Carbamezapine C. Phenytoin D. Gabapentin
- 31. Question 4 What is the target for ablation in Gamma Knife stereotactic radiosurgery in terms of treating trigeminal neuralgia: A. The Gasserion ganglion B. Proximal root and root entry zone C. The main sensory nucleus in brain stem D. The mandibular division (V3) as it exits the skull base
- 32. Question 5 You decide to perform a radiofrequency thermocoagulative ablation for an elderly patient with trigeminal neuralgia that is not a suitable candidate for a retrosigmoid craniotomy. Which of the following fibers are targeted by this modality: A. A-alpha + A-beta fibers B. A-beta + A-delta fibers C. A-delta + C-fibers D. C-fibers and B-alpha fibers
Editor's Notes
- John Fothergill was one of the first physcians, to adequately describe the features of TN and he noted that light touch was the most common trigger. -Tic Dolouloureux comes from the painful facial tics or spasms associated with TN, although its not very common.
- The trigeminal nerve originates from three sensory nuclei, mesencephalic, principle sensory, spinal nuclei of TN and one motor nucleus. At the level of the pons, the sensory nuclei merge to form a sensory root. The motor nucleus continues to form a motor root. In the middle cranial fossa, the sensory root expands into the trigeminal ganglion. The trigeminal ganglion is located lateral to the cavernous sinus in the depression of the temporal bone known as Meckels cave. The peripheral aspect of the trigeminal ganglion gives rise to three divisions, which are the ophthalmic, maxillary, and mandibular branches.
- So in the interest of time I’m not gonna go into much detail of all the three branches and its subdivisions, but what is relevant for us as neurosurgeons to know, is that the motor route passes inferiorly to the sensory route, along the floor of the trigeminal cave. It’s fibers are only distributed to the mandibular division which is V3. The ophthalmic nerve and maxillary nerve travel lateral to the cavernous sinus exiting the cranium via the superior orbital fissure and foramen rotundum. The mandibular nerve exits via the foramen ovale entering the infratemporal fossa.
- Also known as the Jannetta procedure. Peter Janetta was a neurosurgery registrar that first proposed the neurovascular compression theory. He built upon the astute observations of Dandy, Gardner, and others who, in the era before the operating microscope, had successfully ventured into the posterior fossa. Usually indicated for younger, healthier patients that are good surgical candidates. MVD involves exposing the trigeminal nerve at the base of the skull, typically via a craniotomy, and inserting Teflon pads between the artery thought to be compressing the nerve. The chief advantage of this technique is that the pain relief is typically durable and likely curative. Not surprisingly, the use of MVD increased by 194% from 1988 to 2008. However, while MVD remains the treatment of choice for trigeminal neuralgia, it is also the most invasive procedure with the highest rate of complications.
- Radiation is aimed at the proximal root + root entry zone. It works by focusing 201 beams through the skull and brain. A single beam is too small to effect any change by itself but when all 201 beams intersect a very high dose of radiation can be administered with very minimal damage to surrounding tissues.