Clinical Study On Radiofrequency Thermocoagulation In The Treatment Of Maxillary Neuralgia

IntroductionThe incidence of primary trigeminal neuralgia is approximately 4.3-8/100,000.The pain was so intense that it was hard to bear and was called "the most severe pain in the world".Therefore,once the primary trigeminal neuralgia is diagnosed,timely and effective treatment is essential to improve the quality of life of patients.At present,the treatment methods mainly include drug therapy,surgical therapy and intervention,but so far,there is no one of these methods that comply with safety,efficacy and lower recurrence rates.The effect of drug treatment is low,and the curative effect maintains shortly.For example,in the early stage of trigeminal neuralgia,the pain can be effectively controlled by taking antiepileptic drugs,such as carbamazepine,gabapentin.but with the extension of the course,the effect of drug treatment of trigeminal neuralgia will be significantly lower,at last it is invalid.Besides,The side effects will increase significantly with the drug increasing,and the treatment often fail due to the most patients cannot tolerate.The invasive treatment of trigeminal neuralgia includes surgical treatment and minimally invasive interventional therapy.Microvascular decompression is the commonly used and effective method of surgical treatment for trigeminal neuralgia,but most of these patients is too old,frail,not to tolerate surgery.Some of the younger patients were also denied surgical treatment for fear of the risk.The method of minimally invasive interventional treatment is to damage sensory nerve physically or chemically by puncture targets under image guided,such as drug injecting and radiofrequency,so as to achieve effective analgesic action.trigeminal ganglia is most chosen as the target.but the technology willinevitably cause some complications,such as: the function of sensory nerve damage of the cornea,corneal ulcer,damaging of mandibular nerve motor fiber causing chew muscle weakness,intracranial tissue injury.Especially when the trigeminal neuralgia is only involved in the maxillary branch of the trigeminal nerve,the treatment of the trigeminal ganglia is difficult to completely avoid the injury to the ophthalmic branch and the mandibular branch from trigeminal nerve..Therefore,the study of minimally invasive interventional therapy of primary trigeminal neuralgia is of great importance to improve the safety and effectiveness of minimally invasive interventional therapy.Part I: Study on the feasibility of percutaneous radiofrequency thermocoagulation in the treatment of primary maxillary neuralgiaObjective:To investigate the anatomic relations of zygomatic inferior,foramen rotundum and maxilla as well as related factors of puncture effectiveness.To address the feasibility of puncture to foramen rotundum under zygomatic arch.We aim to provide anatomical basis for the treatment of primary maxillary neuralgia with radiofrequency thermocoagulation through foramen rotundum.Methods:With the help of CT spiral scan technique,3D image reconstruction had been conducted basing on the data output from 50 normal skulls.Name the plane of bilateral foramen rotundum and bilateral zygomatic inferior side as working plane,then measure relevant parameters at the working plane.On the side scout view,the line from external auditory canal to palpebral fissure was defined as Line Auditory canal-Palpebral fissure(line EP).Measure the angle from line EP to working plane as angle α.The tangent line of the maxilla that passes through foramen rotundum was defined as Line Foramen rotundum-Zygomatic arch(line FZ).Measure the angle from middle line(M line)to line FZ as angleβ.Then measure distance from the outer edge of foramen rotundum to M line(D1),distance from the intersection of line FZ with skin to M line(D2),distance fromthe intersection of line FZ with skin to foramen rotundum(D3).Record whether the reverse extended line of line FZ intersects with the inner edge of foramen rotundum.Name the parallel line of M line which passes through the center of foramen rotundum as Sagittal line.Record whether the sagittal line intersects with the outer edge of foramen rotundum.Analyze the feasibility of puncture through line FZ and related factors of puncture effectiveness.Conduct comparative analysis to study the anatomical differences between sexes of sample and sides of foramen rotundum.Results:On FZ line,from skin to the outer edge of foramen rotundum are filled with soft tissue,non-bone structure blocking rate reached 100%(50/50).The probability of reverse extended line FZ line intersecting with the inner edge of foramen rotundum is 100%(50/50).The probability of the Sagittal line intersecting with the outer edge of foramen rotundum is 0(0/50).The angle from working plane to line EP,α ranges are in 45.23~50.02°,at the average of 48.30±2.52°.The angle from line FZ to M line,β ranges are in 44.06~52.52°,at the average of 47.14±2.54°.Distance from the outer edge of foramen rotundum to M line,D1 are at the average of 20.01±1.60 mm.distance from the intersection of line EZ with skin to M line,D2 are at the average of 58.41±2.47 mm.distance from the outer edge of foramen rotundum to the intersection of line EP with skin,D3 are at the average of67.81±3.68 mm.The difference of D3 between different gender-specific samples was statistically significant,with p<0.05.whereas the other statistical index between different gender-specific samples and between the left and t right side had no statistical difference with p>0.05.Conclusion:It is feasible to puncture the foramen rotundum through the inferior border of zygomatic arch.By taking β as reference,penetrating can deeper with a curved needle.It can be used to treat maxillary neuralgia with radiofrequency thermocoagulation.Part II: Study on the safety and efficacy of percutaneous radiofrequency thermocoagulation in the treatment of primary maxillary neuralgia witha curved needleObjective:To investigate the effectiveness and possible side effects of radiofrequency thermocoagulation through the foramen rotundum using curved needle for the treatment of maxillary neuralgia.Methods:With the aid of digital subtraction angiography(DSA)3D image,puncture form under the zygomatic arch to foramen rotundum was conducted on 40 maxillary neuralgia patients,followed by radiofrequency thermocoagulation on maxillary nerve under local anesthesia.Using visual analogue scale(VAS)to evaluate therapeutic effectiveness with the pain degrees before procedure,1 week after procedure,6 months after procedure and 12 months after procedure.Statistical analysis was conducted with SPSS 19.0 software.Results:The punctures from the way under the zygomatic arch to foramen rotundum and radiofrequency thermocoagulation were conducted on 40 primary maxillary neuralgia patients,with success rate at 100%.The VAS score of 40 patients are: before procedure at7.18 ± 1.64;one week after procedure at 0.No relapse was reported 6 months or 12 months after the procedure.Incidence rate of facial numbness in maxillary nerve area after surgery was 100%(40/40).swelling in facial region after procedure occurred at the rate of35%(14/40),but disappeared in a week.No functional damage happened on corneal sensory nerve or masticatory muscle.Conclusion:Puncture through foramen rotundum with curved needles is safe and feasible.Radiofrequency thermocoagulation at maxillary nerve is a safe and effective therapy of maxillary neuralgia.Part III: A prospective contrastive study of the treatment of primary maxillary neuralgia by puncturing through foramen rotundum with a curved needle and puncturing through foramen ovale with a straight needleObjective:To compare the safety and effectiveness of radiofrequency thermocoagulation using curved needle for foramen rotundum puncture vs.using straight needle for foramen ovale puncture in treatment of maxillary neuralgia.Methods:primary trigeminal neuralgia patients were randomly separated into the following two groups.Curved needle group: with the aid of X-ray images,puncture through foramen rotundum under zygomatic arch using curved needle,then conduct radiofrequency thermocoagulation on maxillary nerve after electrical test and DSA 3D location confirmation.Control group: puncture through foramen ovale from outer side of angulus oris was conducted.The direction and depth of the needle was adjusted according to electrical test while inserting until it reached the maxillary nerve.Then radiofrequency thermocoagulation was carried out at this area.Using visual analogue scale(VAS)to evaluate therapeutic effectiveness with the pain degrees before procedure,1 week after surgery,6 months after procedure and 12 months after procedure.Statistical analysis was conducted with SPSS 19.0 software.Results:The success rate of procedure on 80 patients was 100%.A week after procedure,VAS of patients from both groups had shown significant reduction compared to the ones before surgery(P<0.01).Average time of procedure in curved needle group is 19.28 ± 5.87 min whereas average time of surgery in control group is 32.73 ± 8.678 min,the difference was statistical significant with p < 0.05.The rate of Pain complete remission at a week after surgery in curved needle group is distinctly higher than control group with p<0.05.The relapse rate after 6 months in two groups had no statistical difference with p>0.05,but the relapse rate after 12 months in curved needle group was significantly lower than control group(p< 0.05).No statistical difference was found in terms of facial numbness and swelling(p>0.05).Incidence rate of functional damage in corneal sensory nerve and masticatory muscle in curved needle group was lower than control group,with p<0.05.Conclusion:Compared with foramen ovale puncture,radiofrequency thermocoagulation through foramen rotundum under the guiding of DSA had better effectiveness,lower relapse and fewer side effects in treatment of trigeminal neuralgia,can be used as ideal treatment of primary maxillary neuralgia.