Trigeminal Neuralgia
Trigeminal neuralgia (TGN), also known as tic douloureux, is sometimes described as the most excruciating pain known to humanity.
Trigeminal neuralgia is sudden, severe facial pain. It’s often described as a sharp shooting pain or like having an electric shock in the jaw, teeth or gums.
It usually happens in short, unpredictable attacks that can last from a few seconds to minutes. The attacks stop as suddenly as they start.
In most cases, trigeminal neuralgia affects just one side of the face, with the pain usually felt in the lower part of the face. Very occasionally the pain can affect both sides of the face, although not usually at the same time.
Treatment Options
Percutaneous Radiofrequency Rhizotomy
A percutaneous rhizotomy is a minimally invasive procedure to treat trigeminal neuralgia.
The rationale of thermal ablation of gasserian ganglion is to interrupt the peripheral stimuli from reaching the central nervous system . Each procedure has its advocates, but the very multiplicity of choices indicates that none is totally satisfactory. But out of the various surgical procedures percutaneous radiofrequency rhizotomy (PRR) is a well established treatment modality.
Foramen Ovale Cannulation is very important step in PRR.
we were familiar with the lateral fluoroscopic approach to the FO as we performed RFR with this technique for last many years.
We have added another technique in our armamentarium.
Flourscopic visualizaiton of Foramen is possible.
Patient is placed in supine position with 40–50° of head extension.
The initial fluoroscope intensifier is positioned with 15° of lateral rotation from midline towards the ipsilateral side and 15° of caudal tilt.
The H-figure landmark is first identified following the medial border of the mandible and the lateral edge of the maxilla as the two vertical lines, and the Superior line of Petrous ridge of Temporal bone (S-P-T line) as the horizontal line.
The FO is then identified above the S-P-T line between the mandible laterally and the maxilla medially.
If the FO is superimposed by the maxilla or mandible, the fluoroscope was then rotated laterally or medially in coronal plane to locate the FO at the middle of H-figure.
if the FO is viewed as a narrow ovale or even a linear shape, then the fluoroscope is rotated in caudal or cephalad direction along the sagittal plane to acquire better visualization of the FO.
After visualization of FO, a 150-mm 22-G straight radiofrequency (RF) needle (Cosman) with a 5-mm active tip was inserted through the sterilized skin in the “Haertel” approach after local tissue infiltration with 5–10 ml 0.5% lidocaine.
The needle tip is advanced through the FO, and the depth of the needle tip did not extend beyond the clivus in the lateral projection.
The position of needle tip is ensured by eliciting the paresthesia or masticatory responses within 1.0 V of sensory (50 Hz) or motor (2 Hz) electrical stimulations with Cosman RF lesion generator, model RFG-4.
Under intravenous anesthesia with propofol (1–2 mg/kg), ganglion neurotomy with RFT is performed at 75°C for 120 seconds to treat V2 and V3.
Department of Neurosurgery Jinnah Hospital is thankful to Professor Abdul Hameed and Dr Talha Abass of Fatima Jinnah Medical University Lahore for teaching us foramen ovale direct visualization technique.
