1. Glossopharyngeal Nerve:
Iram Bokhari

2. Introduction:
Embryologically, the glossopharyngeal nerve is associated with the derivatives of the 3rd pharyngeal arch.

3. Introduction:
Sensory: Innervates the oropharynx, carotid body & sinus, posterior 1/3 of the tongue, middle ear cavity & bony part of Eustachian tube.
Special Sensory: Provides taste sensation to the posterior 1/3 of the tongue.
Parasympathetic: Provides parasympathetic innervations to the parotid gland.
Motor: Innervates the stylopharyngeus muscle of the pharynx.

6. Overview: Branchial Motor (SVE): Supplies Stylophayngeus Muscle
Visceral Motor (GVE): Supplies Secretomotor fibres to Parotid Gland
Visceral Sensory (GVA): Carries Visceral sensation from carotid body & sinus.
Gen Sensory ( GSA): gen sensory sensation from skin of ext ear, internal surface of tympanic membrane, upper pharynx & posterior 1/3rd of tongue
Special Sensory (SVA): carries taste sensation from posterior 1/3rd of tongue.

7. Branches:
Tympanic Nerve of jacobson:  arises from the petrous ganglion, & ascends to the tympanic cavity through a small canal on the under surface of the petrous portion of the temporal bone on the ridge which separates the carotid canal from the jugular fossa. In the tympanic cavity it divides into branches which form the tympanic plexus and are contained in grooves upon the surface of the promontory. This plexus gives off: (1) the lesser superficial petrosal nerve; (2) a branch to join the greater superficial petrosal nerve; & (3) branches to the tympanic cavity
Carotid Branches : descend along the trunk of the internal carotid artery as far as its origin, communicating with the pharyngeal branch of the vagus, & with branches of the sympathetic.  
Pharyngeal Branches: are 3 or 4 filaments which unite, opposite the Constrictor pharyngis medius, with the pharyngeal branches of the vagus & sympathetic, to form the pharyngeal plexus; branches from this plexus perforate the muscular coat of the pharynx & supply its muscles & mucous membrane. 
Muscular Branch: is distributed to the Stylopharyngeus. 
Tonsillar Branches: supply the palatine tonsil, forming around it a plexus from which filaments are distributed to the soft palate & fauces, where they communicate with the palatine nerves. 

18. Jugular Foramen Relations:
Pars Nervosa (anteromedial) = CN IX
Pars Venosa (posterolateral) = CN X & Spinal CN XI
Sigmoid Sinus
Inferior Petrosal Sinus
Meningeal Brances from Ascending Pharygeal & Occipital Arteries 

19. Syndromes Affecting CN IX:
Vernet Syndrome (Intracranial Lesion)    * Loss of taste in posterior 1/3 of tongue. (CN IX)    * Vocal paralysis & anesthesia of larynx & pharynx (CN X)    * Sternocleinomastoid & Trapezius Weakness (CN XI)   Collet-Sicard Syndrome (Extracranial Lesion)    * Vernet plus Hypoglossal Palsy   Villaret Syndrome (Retropharyngeal Lesion)    * Collet-Sicard plus Horner's Syndrome (loss of descending sympathetics) 

20. Collet-Sicard syndrome

21. Villaret Syndrome (Retropharyngeal Lesion)

22. Syndrome Not Affecting CN IX
Tapia:
laryngeal & hypoglossal paralysis

23. Glossopharyngeal Neuralgia

25. Can be associated with:
Trigeminal neuralgia,
Chiari type I malformation
Combined hyperactive dysfunction

26. Trigger Factors: Swallowing is the most common factor,
Cold liquids seem especially to induce pain.
Chewing, talking, sneezing, cleaning the throat, & touching the gums or oral mucosa,
Sudden movements of the head, raising the arm on the side of the pain, & the lateral movement of the jaw may also trigger the paroxysms.
Even touching the external auditory canal, the side of the neck, & the skin anterior to the ear triggered the pain on the same side. 

27. Life threatening complications of GPN:
Harris et al. (1921) reported that GPN could be associated with cardiac dysrhythmia & instability.
This relationship is well-accepted & has been documented by many authors. The various reports & case studies have been compiled & summarized by Ferrante et
Vagoglossopharyngeal neuralgia (VN):

28. Intense irritability & hyper-stimulation of glossopharyngeal nerve
Mechanism:
Intense irritability & hyper-stimulation of glossopharyngeal nerve
Nucleus of the tractus solitarius of the midbrain
Via collaterals
Dorsal motor nucleus of the vagus nerve.

29. Cerebral hypoxia, slowing of EEG activity, syncope, & convulsions.
Manifestations:
Heightened vagal response as cardiac dysrhythmia, bradycardia, & hypotension
Cerebral hypoxia, slowing of EEG activity, syncope, & convulsions.
Convulsive movements, limb clonus, automatic smacking movements of the lips, & upward turning of the eyes are signs of cerebral hypoxia induced by the bradycardia.
The cardiovascular phenomenon is seen during the pain attack or immediately following it.
Both pharmacotherapy & surgical treatment eliminates these.

30. Non- Neuralgic GPN:
There is a subset of patients with demonstrable cardiac manifestations without typical neuralgic symptoms who have responded very well to glossopharyngeal nerve avulsion or MVD.
Such syndromes have been called non-neuralgic GPN, in recognition of the fact that 9th nerve irritability may not always give rise to a pain.

31. Types: Anatomical area Involved Cause based classification
The International Headache Society (IHS) Classification

32. According to Anatomical Involvement:
Otitic type - Pain in and around the ear This is commoner form of the two in the anatomical classification. The pain is often described in relation to the ear. The pain can be of any type, ranging from burning, sharp shooting, shock-like, pressure, pinprick etc. Oropharyngeal - Pain is in & around throat & face region This form has more varied distribution, & significant overlap may occur with other cranial nerve distribution areas.

34. According To Cause:

35. The International Headache Society (IHS) Classification:
1.Classical GPN- episodic pain
2.Symptomatic GPN- continuous pain, commoner

36. Treatment:

37. Pharmacotherapy:
The medications of choice are carbamazepine, gabapentin, & pregabalin although theoretically any membrane stabilizer can be used. 
In addition, low doses of selective serotonin reuptake inhibitors & vitamin B12 can be used.
The use of NSAIDS is not routinely recommended for treating neuralgic pain. It is postulated that neuralgia responsive to NSAIDS is more likely to be due to some unknown acute inflammation.
Opioids have been used as an adjuvant to the frontline neurogenic agents with limited success.
The bad prognostic signs are - bilateral GPN, constant pain, or multiple daily bouts of pain.

38. The International Association for the Study of Pain recommended drugs with their dosages used in GPN:

39. Glossopharyngeal nerve blocks
Can be used for the evaluation of:
Atypical facial pain,
Treatment of GPN,
Intractable pain caused by pharyngeal cancer.
These nerve blocks are excellent adjunct to the pharmacologic treatment of GPN, ensuring rapid palliation of pain.

40. Neurolytic agents are safe alternative to more invasive procedures.
Agents Used:
They can be performed with:
Non-neurolytic agents (local anesthetic agents) with or without additives (steroid, ketamine, etc.)
Neurolytic agents (phenol, alcohol, glycerol, etc)
Neurolytic agents are safe alternative to more invasive procedures.

41. Approaches For Nerve Block:
Intra-oral approach: This block is given using a distally bent spinal needle (approximately 25 degrees) up to a depth of 0.5 cm through the mucosa at the lower lateral portion of the posterior tonsillar pillar. 
  Extra-oral approach: This block is given at the midpoint of on an imaginary line, running from the mastoid process to the angle of the mandible, at a depth of up to 3 cm. The nerve lies immediately below the styloid process at this point , This technique is simpler to perform and is more comfortable to the patient.

42. Diagnostic Value Of Local Blocks:
Cocainization of Pharynx relieves 9th CN pain
Cocainization of Pyriform fossa relieves neuralgia of superior laryngeal branch of X CN
Blocking Foramen Ovale with Bupivacaine, it is possible to determine component of pain due to 3rd Div of V CN
Tetracaine block of Jugular foramen will block all afferent impulses via 9th & 10th CNs & help to sort out pain mediated by nervus intermedius

43. Complications of GPN block:
i/v injection can occur into the carotid artery or into the IJV.
Difficulty in swallowing & hoarseness can result from the glossopharyngeal & vagus (recurrent laryngeal branch) nerve blocks, respectively.
Bilateral GPN block can cause bilateral vocal cord paralysis, hence bilateral block is not recommended.
The loss of parasympathetic outflow with vagus nerve blockade could cause tachycardia & hypertensive response

44. Surgical Therapy Peripheral procedures:
Extra cranial, such as direct surgical neurotomies or percutaneous radiofrequency thermal rhizotomy
Intracranial, such as direct section of glossopharyngeal & vagal nerves in the cerebello-pontine angle 
Central procedures: such as percutaneous or open trigeminal tractotomy-nucleotomy or nucleus caudalis DREZ operation

45. Indications for Extracranial Procedures:
Extracranial neurotomy & percutaneous radiofrequency rhizotomy are restricted to those patients who have failed medical therapy, short life expectancy & cannot tolerate an open intracranial procedure.

46. Pulsed radiofrequency neurolysis (PRN) & gamma knife surgery (GKS).
Recently, various case reports have been published, which have shown PRN is a non-destructive neuromodulatory method to treat both, idiopathic & secondary GPN. 
Short pulses of radiofrequency energy, delivered at a constant temperature, produce central & peripheral neuromodulatory effects.
In GKS system, an 80 Gy dose is stereotactically directed to the isocenter with MR imaging-based target localization & 4-mm collimation.
It might serve as a potential alternative to other percutaneous techniques & surgical options for patients with secondary GPN.
Stereotactic radiosurgery (SRS) with GKS system offers a less-invasive option for patients with GPN.  

47. Percutaneous Radiofrequency Ablation:
It has been suggested but has been associated with inadvertant risk to X CN
Vocal cord paralysis occurred after rhizotomy & a
Repeated aspiration pneumonia
When swallowing mechanism has already been altered by malignant disease RF ablation procedures are recommended

48. Surgical Therapy:
These days, the best-established surgical treatments are MVD of vascular roots & rhizotomy of the glossopharyngeal nerve with upper vagal nerve roots

49. Complications: Sensation diminished over the pharynx
Abolished gag Reflex
Absence of Taste
Transient difficulty in swallowing
i/ operative hypertensive crisis with i/c haemorrhage
Physiological i/ operative changes: extrasystoles everytime vagus is touched followed by hypotension, which responded to atropine, Suring tteck RBB block leading to coronary artery insufficiency & thus MI

50. First address the underlying pathology,
In secondary GPN:
First address the underlying pathology,
when MVD is not possible, intracranial root section is considered curative & is most widely employed.

51. Thank You