Stereotactic Technique Application In Radiofrequency Thermocoagulation For Trigeminal Neuralgia With Puncture Difficult Foramen Oval And In Complex Intracranial Lesions

Background:With the development of minimally invasive surgical techniques and molecular pathology,stereotactic surgery plays a crucial role in the field of neurosurgery.Stereotactic surgery mainly includes:（1）percutaneous radiofrequency thermocoagulation（PRT）for the treatment of primary trigeminal neuralgia including the recurrent cases;（2）stereotactic biopsy（STB）offers exact pathological classification of intracranial tissue for further radiation therapy or molecularly targeted drugs;（3）Stereotactic Aspiration（SA）for aspiration of intracranial hematomas,particularly at specific sites hematoma,such as brain stem hematoma,is of important to save the patient’s life and obtain a satisfactory prognosis;stereotactic aspiration of the brain abscess,followed by pus culture and drug susceptibility testing,which is helpful to clear the rational use of antibiotics and control the development of the disease as early as possible.For ganglion destruction of trigeminal neuralgia with difficult puncture foramen oval,doctors around the world are constantly adopting new objective and accurate methods;the relationship between brain biopsy and molecular pathology has received great attention^[1];for brain stem hematoma,especially pontine hematoma,diagnosis and treatment of unclear brain abscess,safer and more effective solutions are under discussion^[2,3].Objectives:（1）To observe the stereotactic surgery combine with three-dimensional computed tomography（3D-CT）reconstruction on the unconventional facial puncture site previous choosing in percutaneous radiofrequency thermocoagulation of trigeminal neuralgia as well as to analyze the difficulty factors of puncture and surgical planning;（2）To observe the function and effectiveness of stereotactic surgery combining imaging technology in the diagnosis and treatment of complex intracranial lesions.Methods:1.For ganglionic surgery of trigeminal neuralgia with puncture difficult foramen oval:（1）51 patients in this group underwent thin-slice CT（0.625mm slice thickness）scans before surgery.Then creat Three-dimensional CT reconstruction of skull.（2）Use the 3D CT reconstruction image.Marked the unconventional facial penetration point.（3）Correcting the puncture angle to avoid the occlusions if the puncture path was obscured.（4）After the puncture was completed,the position of the puncture needle tip in the foramen oval was verified by a C-arm X-ray machine.Based on the electrophysiological test,the target of thermocoagulation was determined and then radiofrequency thermocoagulation was performed.（5）Determined the efficacy of surgery based on Visual Analogue Score（VAS）.2.For stereotactic intracranial biopsy,intracranial hematoma and brain abscess aspiration surgery cases:（1）14 patients underwent thin-slice CT scans used for 3D CT reconstruction before operation.The CT reconstruction images accurately located the lesion location,especially the location and measuring the exact volume of the hematoma.Frame stereotactic apparatus was used to obtain the lesion locates in the three-dimensional coordinate system.（2）The puncture point of the lesion and cranial were confirmed.（3）Determining the puncture point into the skull according to the data,the biopsy device went deep into the target,or used a syringe to aspiration of hematoma or abscess.（4）The aspiration were used for postoperative pathological analysis,pus culture or drug sensitivity test.（5）According to pathological analysis,culture or drug sensitivity test results were applied for further treatment.（6）Through follow-up observation,postoperative complications and postoperative efficacy could be found.Results:1.（1）51 patients in this group,the maximum transverse diameter of the foramen ovale was 2.2-10mm（mean 5.9mm）,and the maximum anterior–posterior diameter was 1.7mm-6mm（mean 2.4mm）.The average diameter of the foramen oval area was（14.16mm²）in the 3D CT reconstruction image of the direction of the trajectory.（2）Observing whether the puncture path is blocked:among the 51 patients in this group,12 patients were blocked from the typical estimation of the facial entry point（The usual site of needle insertion for this procedure was approximately 2.5 cm laterally from the corner of the mouth on the symptomatic side）.8 patients had the trajectory obstructed by the external pterygoid plate（8/51,15.7%）,3 patients had the trajectory obstructed by mandibula（3/51,5.9%）,and 1 patient had the trajectory obstructed by tooth（1/51,1.9%）.In addition,3 cases were obstructed because the distance between the mandible and tooth ridge（8.5mm,9.0mm,and 9.7mm,respectively）was too small,and the mouth was maintaining open position both during CT scanning and operation.（3）Creating a 3D face image and marking the facial penetration point,the distances from the needle insertion sites was laterally to the mouth corners 22mm for the minimum distance,41.5mm for the maximum.（4）Statistical analysis showed that there was no significant difference in VAS scores on the 1st day,3rd day,10th day,and 3rd months postoperative days between the foramen oval without blocked group and blocked group（P>0.05）.there was statistical significance of the VAS scores of the foramen ovale between the puncture area>15.0mm² group and<15.0 mm² group in the 1st day,3rd day,10th day and 3rd months after operation（P<0.05）.（5）Complications and recurrences:3 cases（3/51,5.9%）recurred 2 years after operation,2 cases were refractory to recurrent radiofrequency therapy,and 1 patient had microvascular decompression.Eight patients（8/51,15.7%）had mild facial numbness after surgery and the symptoms of numbness disappeared within 3-5 months after surgery.2.There were 14 cases of stereotactic biopsy and stereotactic aspiration.10 cases obtained definite pathological diagnosis,1 case did not get clear definite pathological diagnosis.2 cases obtained definite pathogenic bacteria by microbiological culture.The positive rate of biopsy was 92.3%.There were 4 cases underwent stereotactic aspiration.After the operation,2 cases of brain abscess were cured.The patients with brainstem metastasis were treated combined with gamma knife radiosurgery after aspiration,and the patient survived for 12 months following the procedure.By the3-year follow-up visit,the patient was conscious,had regained the ability to speak a few words,and could walk with the help of rehabilitation equipment.Conclusion:（1）Combining three-dimensional CT reconstruction images to determine unconventional facial puncture points,and sensory stimulation were conducted to confirm the target,so it is safer and more efficient to complete stereotactic radiofrequency thermal coagulation surgery for patients having difficulty in puncturing the foramen oval.（2）Stereotactic biopsy and aspiration are extremely safe and effective in the diagnosis and treatment of intracranial abscess.（3）Combining the stereotactic approach with 3D CT reconstruction models are likely to be of substantial benefit to help neurosurgeons more accurately visualize the exact location and volume of the hematoma.