A Comparative Study Of Preoperative Imaging And Intraoperative Microscopic Anatomy On Primary Hemifacial Spasm

Objective Identify the responsible blood vessels before operation by facial nerve 3D-TOF-MRA and 3D-FIESTA scan; measure the size of the cerebellopontine angle cistern by preoperative brain T2 image scan to determine the difficulty of the operation; assess the patient’s prognosis by postoperative facial nerve 3D-TOF-MRA scanning.Method Our hospital has treated 125 cases of primary hemifacial spasm from 2004 to 2011, of which 80 cases had preoperative facial nerve MRA scan. Analyze preoperative and postoperative facial nerve MRA of 80 cases to determine the source, number, location and etc. of responsible blood vessels, comparing with intraoperative facts; determine the prognosis of patients according to existence of suspicious vessels in postoperative facial nerve REZ. SPSS10.0 statistical software was adopted to analyze data. Measure the size of cerebellopontine angle (CPA) cistern by the preoperative axial T2 brain MRI scan, compare the difficulty of operation, and analyze data by SPSS10.0. The transverse incision of suboccipital retrosigmoid approach for microvascular decompression (MVD) was adopted in the surgery.Result Responsible blood vessels were found in all 80 cases of hemifacial spasm patients by the preoperative MRA scan.60 patients (75%) were single vessel cases, of which 57 cases were anterior inferior cerebellar artery(AICA), 1 for posterior inferior cerebellar artery(PICA),1 for superior cerebellar artery(SCA),1 for vertebral artery(VA).9 patients (11.25%) were two or more vessels, of which 8 cases were AICA+internal auditory artery,1 for PICA+ internal auditory artery. The source of responsible vessels of 11 cases cannot be determined before surgery. By intraoperative anatomy, we found that:59 patients were single vessel cases, of which 53 cases were AICA,4 for PICA,1 for SCA,1 for VA.14 patients were multiple vessels cases, of which 7 cases were AICA+internal auditory artery,2 for internal auditory artery+PICA,3 for AICA+brain stem perforating artery,2 for AICA+vein.7 cases were uncertain. Comparing the preoperative MRA scan with the intraoperative anatomy by statistical analysis, there was no significant difference between the two groups (P> 0.05). Comparing the size of cerebellopontine angle cistern displayed by preoperative axial T2 brain MRI scan with patients ages and the difficulty of operation through the statistical analysis, the differences were significant (P= 0.000). The comparison between the existence of suspicious vessels in REZ displayed by postoperative facial nerve MRA scan and prognosis showed that the difference was significant according to the statistical analysis(P= 0.000).Conclusion1. Special sequences of preoperative facial nerve MRA scan can identify the situation of responsible blood vessels of patients with primary hemifacial spasm; cerebellopontine angle cistern measurement can determine the difficulty of operation. In that case, preoperative facial nerve MRA scan plays a guided role in the surgery obviously.2. It is difficult to determine the presence of multiple responsible vessels before operation by 3D-TOF-MRA, especially the compression in veins and brain stem perforating arteries.3. The cerebellopontine angle cistern increased in patients over the age of 40, especially those over the age of 60. It is quite beneficial for the exposure of facial nerve REZ in the surgery, making the operation much easier.4. Postoperative facial nerve 3D-TOF-MRA scan can obtain the drift of the responsible blood vessels and the presence of suspicious vessels in facial nerve REZ after operation, which are important for prognosis judgement. Objective Identify the responsible blood vessels before operation by facial nerve 3D-TOF-MRA and 3D-FIESTA scan; measure the size of the cerebellopontine angle cistern by preoperative brain T2 image scan to determine the difficulty of the operation; assess the patient’s prognosis by postoperative facial nerve 3D-TOF-MRA scanning.Method Our hospital has treated 125 cases of primary hemifacial spasm from 2004 to 2011, of which 80 cases had preoperative facial nerve MRA scan. Analyze preoperative and postoperative facial nerve MRA of 80 cases to determine the source, number, location and etc. of responsible blood vessels, comparing with intraoperative facts; determine the prognosis of patients according to existence of suspicious vessels in postoperative facial nerve REZ. SPSS10.0 statistical software was adopted to analyze data. Measure the size of cerebellopontine angle (CPA) cistern by the preoperative axial T2 brain MRI scan, compare the difficulty of operation, and analyze data by SPSS10.0. The transverse incision of suboccipital retrosigmoid approach for microvascular decompression (MVD) was adopted in the surgery.Result Responsible blood vessels were found in all 80 cases of hemifacial spasm patients by the preoperative MRA scan.60 patients (75%) were single vessel cases, of which 57 cases were anterior inferior cerebellar artery(AICA), 1 for posterior inferior cerebellar artery(PICA),1 for superior cerebellar artery(SCA),1 for vertebral artery(VA).9 patients (11.25%) were two or more vessels, of which 8 cases were AICA+internal auditory artery,1 for PICA+ internal auditory artery. The source of responsible vessels of 11 cases cannot be determined before surgery. By intraoperative anatomy, we found that:59 patients were single vessel cases, of which 53 cases were AICA,4 for PICA,1 for SCA,1 for VA.14 patients were multiple vessels cases, of which 7 cases were AICA+internal auditory artery,2 for internal auditory artery+PICA,3 for AICA+brain stem perforating artery,2 for AICA+vein.7 cases were uncertain. Comparing the preoperative MRA scan with the intraoperative anatomy by statistical analysis, there was no significant difference between the two groups (P> 0.05). Comparing the size of cerebellopontine angle cistern displayed by preoperative axial T2 brain MRI scan with patients ages and the difficulty of operation through the statistical analysis, the differences were significant (P= 0.000). The comparison between the existence of suspicious vessels in REZ displayed by postoperative facial nerve MRA scan and prognosis showed that the difference was significant according to the statistical analysis(P= 0.000).Conclusion1. Special sequences of preoperative facial nerve MRA scan can identify the situation of responsible blood vessels of patients with primary hemifacial spasm; cerebellopontine angle cistern measurement can determine the difficulty of operation. In that case, preoperative facial nerve MRA scan plays a guided role in the surgery obviously.2. It is difficult to determine the presence of multiple responsible vessels before operation by 3D-TOF-MRA, especially the compression in veins and brain stem perforating arteries.3. The cerebellopontine angle cistern increased in patients over the age of 40, especially those over the age of 60. It is quite beneficial for the exposure of facial nerve REZ in the surgery, making the operation much easier.4. Postoperative facial nerve 3D-TOF-MRA scan can obtain the drift of the responsible blood vessels and the presence of suspicious vessels in facial nerve REZ after operation, which are important for prognosis judgement.