Offending Vessels Research Articles

Microsurgical Procedures of Microvascular Decompression for Trigeminal Neuralgia

Microvascular decompression for trigeminal neuralgia was successfully performed following the secure surgical steps. The most crucial step involves creating a safe operative field in the dural opening. The petrotentorial junction should be identified without cerebellar retraction before proceeding to the deeper areas. Dissecting the petrosal vein and opening the horizontal fissure contributed to the expansion of the operative field. Bleeding often occurs from the dorsal cerebellar bridging vein and junction of the petrosal vein into the superior petrosal sinus. Transposition of the most common offenders, the superior and anterior inferior cerebellar arteries, is effectively achieved by dissecting both the proximal and distal sides of the neurovascular compression site. Teflon should be placed at a sufficient distance to prevent contact with the nerve, which can lead to recurrence. Treating vertebrobasilar artery-related cases is challenging and involves the risk of cranial nerve injuries. Multiple offending vessels are commonly involved. In such cases, it is essential to be aware of the course of the trochlear and abducens nerves during decompression. Applying the most effective and least risky maneuver is necessary for treating cases involving the vertebrobasilar artery.

Microvascular decompression for hemifacial spasm: Complications after 292 procedures without neurophysiological monitoring.

Hemifacial spasm (HFS) is characterized by involuntary, progressive, and intermittent spasms in the upper and lower facial muscles. Due to the high success rate, microvascular decompression (MVD) is the treatment of choice, and intraoperative neuromonitoring (INM) is considered useful for achieving safe surgery. Still, most centers do not have this technology. We analyzed 294 patients with HFS treated with MVD without INM. We only included patients with a neurovascular etiology while excluding other causes, such as tumors. As part of the postoperative evaluation, we assessed preoperative magnetic resonance imaging and pure-tone audiometry. The main complication was peripheral facial paralysis in 50 patients, followed by hypoacusis in 22 patients and deafness in 17 patients, associated with a failed surgical outcome (P = 0.0002). The anterior inferior cerebellar artery (AICA) was an offending vessel, and the involvement of more than one vessel was significantly associated with the development of facial nerve palsy (P = 0.01). AICA was also associated with hearing impairment (P = 0.04). Over 90% of immediate complications improve in the follow-up (6 months), and one patient did not show a cure for initial HFS. MVD is the method with the highest long-term cure rates for treating HFS; however, we must inquire into the multiple factors of the patient and the surgeon to predict surgical outcomes. INM is not a must during MVD for HFS. We recommend its use depending on the availability and mainly on the surgeon's skills, for surgeons.

Meckel’s cave compression with Teflon for the treatment of idiopathic trigeminal neuralgia: its possibility as a modified surgical technique

Objective: We analyzed the clinical outcomes of Meckel’s cave compression with Teflon (Rhee’s method) as a new modified and additional surgical technique for trigeminal neuralgia (TN).Methods: Between March 1996 and December 2014, out of 78 patients who were treated with microvascular decompression (MVD) or partial sensory root rhizotomy, 28 patients additionally underwent Meckel’s cave compression with Teflon. The mean age at initial treatment was 54.3 years (range: 40–69 years). The mean duration from onset to operation was 70.5 months (range: 5–360 months) and the mean follow-up period was 26 months (range: 1–77 months). Results: Fifteen patients (53.6%) had facial pain in the V2/V3 distribution. The offending or associating vessel was the superior cerebellar artery in four patients (14.3%), the superior petrosal vein in six (21.4%), the anterior inferior cerebellar artery in two (7.1%), multiple vessels in nine (32.1%), and miscellaneous arteries or veins in six (21.4%). One patient (3.6%) had no offending vessel, and seven patients were had no definite offending vessels that contacted the trigeminal root entry zone. Meckel’s cave compression with Teflon was applied to all patients: 10 (35.7%) in combination with MVD, one (3.6%) with partial rhizotomy, and 17 (60.7%) with both MVD and partial rhizotomy. TN was relieved in 26 patients (92.9%) and symptoms recurred in three patients (pain-free rate: 82.1%). The complication rate of this method appeared to be similar to other treatment procedures. Conclusion: Meckel’s cave compression with Teflon may be a safe and useful additional treatment procedure for TN.

A Combination of 3D TOF MRA and FIESTA Predicts Surgery-Needed Primary Trigeminal Neuralgia and Specific Offending Vessels.

To investigate the predictive accuracy of three-dimension (3D) time-of-flight (TOF) MR angiography (MRA) and 3D Fast Imaging Employing Steady-state Acquisition (FIESTA) techniques in assessing neurovascular compression (NVC) with specific vessels in patients with primary trigeminal neuralgia (TN). Patients with single-site primary TN undergoing microvascular decompression (MVD) were retrospectively recruited. All patients had available preoperative magnetic resonance imaging (MRI) scans. A quantitative NVC scoring system was applied to assess the severity of NVC on MRI. The radiological findings were correlated with the intraoperative result to determine the diagnostic accuracy of MRI techniques. Besides, the radiological indicator of MVD was determined. Seventy-three TN patients were recruited. Thirty-three patient had bilateral NVC but with unilateral neuralgia. The average NVC score of the asymptomatic side was significantly lower than that of the symptomatic side (1.6 vs. 6.7; p < 0.001). A cut-off value of NVC >4 was determined as a radiological indicator of MVD with sensitivity and specificity of 82.2% and 98.6%, respectively Area Under Curve (AUC = 0.97; p < 0.001). Approximately 90% of symptomatic patients had the distance to REZ ≤3 mm. 68.5% of patients had a single conflicting vessel, and superior cerebellar artery (SCA) was the predominate vessel (46.6%). The sensitivity and specificity of MRI to detect NVC were 95.8% and 100%, respectively. Regarding each vessel, the cohen's kappa statistic (K) was 0.632 overall. 3D TOF MRA and FIESTA show an overall good ability to predict specific offending vessels. NVC score >4 is identified to predict TN, suggestive of subsequent surgical treatment.

Microvascular triple decompression for combined simultaneous trigeminal neuralgia, hemifacial spasm, and pulsatile tinnitus due to separate offending vessels

Neurovascular compression syndrome is generally caused by vascular compression at the root entry or exit zone of the corresponding cranial nerve. Trigeminal neuralgia is the most frequent syndrome, followed by hemifacial spasm. Despite ongoing debate in the literature, pulsatile tinnitus is also known to be a neurovascular compression syndrome resulting from vascular compression of the vestibulocochlear nerve. Combined manifestations of neurovascular compression symptoms are very rare. We report a case with a simultaneous manifestation of trigeminal neuralgia, hemifacial spasm, and pulsatile tinnitus as neurovascular compression syndrome with separate offending vessels. A 53-year-old female presented with lancinating pain in the left face, left hemifacial spasm, and ipsilateral pulsatile tinnitus for 2 years. Trigeminal neuralgia and hemifacial spasm were diagnosed after a neurological examination, imaging study, and electromyography. Microvascular decompression via a retrosigmoid approach for separate offenders, including the superior cerebellar artery, anterior inferior cerebellar artery, and posterior inferior cerebellar artery was performed using Teflon sponges. The patient’s hemifacial spasm, pulsatile tinnitus, and hemifacial pain improved immediately after microvascular decompression.

Microvascular decompression in trigeminal neuralgia with the offending artery transfixing the nerve: a case report

BackgroundAn anterior inferior cerebellar artery (AICA) that crosses the right trigeminal nerve is an uncommon arterial anatomic variation. In this anatomical position, it is difficult to separate or move the offending blood vessels and nerves. We report an uncommon case of trigeminal neuralgia (TN) caused by compression of the trigeminal ganglion by a branch of the AICA.Case presentationA 34-year-old man with 5 years history who complained of pain on the right side of the face (area V1). The symptoms gradually worsened, and the pain episodes became intense and frequent. Magnetic resonance imaging (MRI) of the cerebrum showed a small blood vessel passing through the right trigeminal nerve. Microvascular decompression (MVD) was performed,because medication was ineffective. Intraoperative exploration confirmed that the vessel which was a branch of the AICA passing through the right trigeminal nerve. As while the artery was temporarily clipped, electrophysiological monitoring showed a decrease in the amplitude of nerve activity. As the artery was considered too important to be sacrificed, the space between the nerves was enlarged mildly, the artery was liberated, the Teflon implant was shredded and placed between the artery branches and nerve to make the blood vessels as perpendicular as possible to the nerve. The patient had no neurological dysfunction and no pain after 8 months of follow-up.ConclusionMVD is an effective treatment for artery-induced trigeminal nerve compression, but we report a novel procedure that avoids the complication of facial numbness caused by cutting the offending vessels and incision of the trigeminal nerve.

The preoperative evaluation value of 3D-slicer program before microsurgical vascular decompression in patients with hemifacial spasm

BackgroundTo compare the diagnostic accuracy of 3D fast imaging employing steady-state acquisition (FIESTA) combined with 3D-time-of-flight (TOF) MR angiography (MRA) sequences (FTMS) and 3D-reconstuction synthesized by 3D-slicer program in evaluation the neurovascular relationships and offending vessels preoperatively in patients with hemifacial spasm (HFS). MethodsClinical data of HFS patients who underwent microsurgical vascular decompression (MVD) were analyzed. All patients underwent MRA scans with FTMS and 3D-reconstruction before surgery. The neurovascular relationship and offending vessels were evaluated and compared with intraoperative findings. ResultsForty patients were included in this study, 18 (45%) of them were male. The mean age was 49.6 years. The Kappa identity tests identified the agreement between the FTMS and intraoperative findings in evaluating the neurovascular relationship and offending vessel was 0.263 and 0.643, respectively. The agreement between the 3D-reconstruction and intraoperative findings was 0.633 and 0.921 respectively. There was borderline significant difference between the two methods in predicting neurovascular relationship (χ2 = 9.363, P = 0.053), and there were significant differences between the two methods in predicting offending vessels (χ2 = 188.408, P < 0.001). The sensitivity and specificity of FTMS in evaluating the neurovascular relationship were 89.7% and 100%, respectively, while those with 3D-reconstruction were both 100%. Moreover, the correct 3D- reconstruction examinations in predicting vessel and nerve relationships (r = 0.634, P = 0.034) and offending vessels (r = 0.652, P = 0.028) were significantly correlated with completely symptoms remission. ConclusionsThe 3D-reconstuction synthesized by 3D-slicer program was more accurate than FTMS in preoperative evaluation of neurovascular relationship and offending vessel. The technique is expected to be helpful in preoperative evaluation. Availability of data and materialThe dataset used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Significance of different offending vessels and development of a potential screening tool for trigeminal neuralgia.

This study was performed amongst trigeminal neuralgia (TN) patients with neurovascular contact (NVC) to 1) investigate the association of the demographic and radiologic factors/variables with TN occurrence, and 2) develop a screening tool for TN/TN-affected nerves based on the factors/variables associated with it. Eighty-five TN patients were recruited, and 121 trigeminal nerves with NVC were derived from them. Based on MRI sequences, including balanced turbo field echo and enhanced T1 high-resolution isotropic volume excitation, radiologic factors/variables for each nerve, from the offending vessel to the presence of nerve displacement, were identified by a neuroradiologist and a neurosurgeon. Demographic and clinical data were obtained from clinical notes. Logistic regression was performed to assess the association of the factors/variables with TN occurrence (i.e., affected vs. unaffected nerves). Three factors/variables were significantly (p<0.05) associated with TN occurrence amongst patients with NVC: nerve laterality, vertebral artery (VA) involvement, and the presence of nerve displacement. The nerves with VA involvement, those on the right side, and those with nerve displacement exhibited a significantly higher likelihood/odd of being affected by TN, compared to those without VA involvement, those on the left side, and those without nerve displacement, respectively. Based on these factors/variables, a screening tool/nomogram with acceptable accuracy was established (C-statistic/AUC = 0.80). This study revealed an association of the three radiologic factors/variables with TN occurrence. A screening tool for TN/TN-affected nerves was established based on them. The findings may lay a foundation for an improvement of the diagnosis and clinical management of TN. • VA involvement and nerve displacement could be identified using MRI, and are significantly associated with TN occurrence. • A potential objective screening tool/nomogram for TN/TN-affected nerves could be established based on the three radiologic factors/variables: VA involvement, the presence of nerve displacement, and nerve laterality. • The screening accuracy of the tool/nomogram is acceptable as the C-statistic is 0.80.

Treatment Strategies for Different Types of Intraneural Offending Vessels in Microvascular Decompression Surgery for Trigeminal Neuralgia: An Analytic Report of 58 Cases.

Microvascular decompression (MVD) surgery is the treatment of choice for trigeminal neuralgia (TGN). However, decompression becomes difficult when the offending vessel penetrates the trigeminal nerve root. To estimate the rates and patterns of different types of intraneural offending vessels in patients with TGN for MVD and to discuss respective management strategies. All patients with TGN undergoing MVD in our center from January 1, 2015, to December 31, 2019, were analyzed retrospectively. The intraneural offending vessels included veins and arteries. The postoperative pain relief rate, complications, and recurrences were evaluated. Of the 302 TGN cases, the intraneural offending vessels were identified in 58 of the cases (19.2%). The 9 cases (15.5%) of intraneural offending arteries were decompressed using shredded Teflon wrapping interposition. Of the 49 cases (84.5%) of intraneural offending veins (INOVs), 29 were not considered true offending vessels, and the treatment only addressed the offending artery in these patients. Of the remaining 20 INOVs, 15 were electrocoagulated and divided, and 5 were decompressed with shredded Teflon. Complete pain relief was achieved in all 58 patients. However, the pain recurred in 5 patients (8.6%), and transient hemifacial numbness occurred in 4 patients (6.9%). Intraneural offending vessels requiring treatment are uncommon and are seen in less than 1 in 10 patients undergoing MVD for TGN. For intraneural offending artery, decompression by shredded Teflon wrapping interposition is recommended. Management of the INOV depends on the individual situations, and the management includes sacrifice, wrapping decompression, or leaving them untreated.

Microvascular Transposition Without Teflon: A Single Institution's 17-Year Experience Treating Trigeminal Neuralgia.

Trigeminal neuralgia (TN) refractory to medical management is often treated with microvascular decompression (MVD) involving the intracranial placement of Teflon. The placement of Teflon is an effective treatment, but does apply distributed pressure to the nerve and has been associated with pain recurrence. To report the rate of postoperative pain recurrence in TN patients who underwent MVD surgery using a transposition technique with fibrin glue without Teflon. Patients were eligible for our study if they were diagnosed with TN, did not have multiple sclerosis, and had an offending vessel that was identified and transposed with fibrin glue at our institution. All eligible patients were given a follow-up survey. We used a Kaplan-Meier (KM) model to estimate overall pain recurrence. A total of 102 patients met inclusion criteria, of which 85 (83%) responded to our survey. Overall, 76 (89.4%) participants responded as having no pain recurrence. Approximately 1-yr pain-free KM estimates were 94.1% (n=83), 5-yr pain-free KM estimates were 94.1% (n=53), and 10-yr pain-free KM estimates were 83.0% (n=23). Treatment for TN with an MVD transposition technique using fibrin glue may avoid some cases of pain recurrence. The percentage of patients in our cohort who remained pain free at a maximum of 17 yr follow-up is on the high end of pain-free rates reported by MVD studies using Teflon. These results indicate that a transposition technique that emphasizes removing any compression near the trigeminal nerve root provides long-term pain-free rates for patients with TN.

Small Posterior Cranial Fossa and Cerebellopontine Cistern Volumes Are Associated With Bilateral Trigeminal Neuralgia.

Objective: To investigate whether small volumes of the posterior cranial fossa and cerebellopontine cisterns are associated with bilateral trigeminal neuralgia (BTN) and to provide further knowledge regarding the etiology and treatment of this rare disease.Methods: We retrospectively analyzed clinical data and imaging examination results for 30 BTN patients between January 2009 and December 2019. Thirty age- and sex-matched healthy individuals and 30 patients with unilateral trigeminal neuralgia (UTN) were selected as two control groups. The volume of the posterior cranial fossa (VPCF) and volumes of the cerebellopontine cisterns were measured using ITK-SNAP 3.0, which considers the cerebrospinal fluid (CSF) volume based on the region of interest (ROI). Preoperative and postoperative statuses were based on visual analog scale (VAS) pain scores and Barrow Neurological Institute (BNI) scores.Results: A total of 30 patients (11 males; 19 females) were included, and the age of the BTN participants ranged from 41 to 77 (59.93 ± 9.89) years. The duration of TN ranged from 1 to 20 (5.36 ± 3.92) years, and the interval between the two sides ranged from 0 to 3 (1.10 ± 0.79) years. Three patients (10%) in the BTN group had familial trigeminal neuralgia, with no other hereditary history of neurological disorders. In BTN patients, with 25 (83.3%) cases on the left side and 26 (86.7%) on the right side, veins were identified in the operative field and regarded as the individual or offending vessel. The mean VPCF was significantly lower in the patients with BTN than in the healthy controls (4,813 ± 1,155 mm3 vs. 5,127 ± 1,129 mm3, p = 0.008). The volumes of the cerebellopontine cisterns on both sides were significantly smaller in the BTN patients than in the healthy controls (477 ± 115 mm3 vs. 515 ± 112 mm3 on the left side, p = 0.001; and 481 ± 114 mm3 vs. 515 ± 110 mm3 on the right side, p = 0.007). There was no significant difference between the BTN group and the UTN group in terms of the VPCF (4,843 ± 1,184 mm3 vs. 4,813 ± 1,155 mm3, p = 0.402), and there was also no significant difference between the two groups in terms of preoperative VAS pain scores or BNI scores.Conclusion: Overcrowding in the posterior fossa will lead to closer neurovascular relations and, a higher incidence of NVC, and ultimately may be more likely to lead to TN. Veins are the common offending vessels that cause BTN; they might be associated with abnormal vascular development leading to NVC. Microsurgical vascular decompression (MVD) is a safe and effective method for the treatment of BTN, similar to UTN.

Image diagnosis of Trigeminal Neuralgia caused by Vascular Compression

Trigeminal Neuralgia (TGN) is a disease frequently encountered by the neurologists and neurosurgeons. The typical pain of TGN is lancinating in nature in one side of face along the distribution of Trigeminal nerve. Pain is sharp shooting and periodic in nature, aggravated by various factors, like eating, talking, laughing. A typical trigeminal neuralgia is caused by compression to the Root exit zone (REZ) by superior cerebellar artery (SCA), aberrant loop of Antero inferior cerebellar artery (AICA), dolichobasilar artery or a large sized vein. However facial pain mimicking TGN may occur by a tumor, plaque of Multiple sclerosis or may be idiopathic. So this is very important to know the cause of TGN/ facial pain for planning of specific treatment. Most of the patients remain pain free by medical management by using Carbamazepine, oxycarbazepine, Pregabalin, Gabapentin, Clonazepam etc. But medically refractory TGN can be treated by Microvascular decompression (MVD) with significantly satisfactory results if the cause is by vascular compression. However during MVD no significant blood vessels are seen and surgery become failed. Clinical examination and evaluation is very important, however to become confirmed about the pathogenesis needs imaging of brain. MRI of brain can differentiate any tumor or Plaque of MS. But conventional MRI images can not show us clearly the blood vessel causing TGN. Conventional MRA could show the blood vessels, which might be causing compression to REZ but does not confirm the fact. Constructive interference in steady state (CISS) MR images were evaluated in our 15 cases to find neurovascular relationship at the REZ. In 11 cases CISS images showed excellent visualization of fifth nerve and blood vessels causing compression to REZ in all case of TGN who underwent Microvascular decompression (MVD) with excellent result. In 2 patients we depended on clinical findings and T2 MR Images. In one of them we could find Offending vessels who were also improved clinically. In one case we did not find any significant offending vessel except a small vein and this patient did not show any improvement. In rest two cases, in one patient CISS showed a tiny vessel and after MVD the patient did not improve. In one patient no significant vessels were not seen in CISS images. We did not go for MVD for this case. So the pre-operative CISS MR images are more precise to show the neurovascular relationship and determine the offending blood vessel causing TGN. Thus we can avoid an unnecessary MVD.&#x0D; Bang. J Neurosurgery 2020; 10(1): 3-8

Microvascular decompression for hemifacial spasm associated with distinct offending vessels: A retrospective clinical study

ObjectiveTo investigate the surgical effects and complications of microvascular decompression (MVD) for hemifacial spasm (HFS) based on different offending vessels, and report our surgical experience of HFS patients related to vertebral artery. Patients and methodsMVDs performed in Nanjing Drum Tower Hospital between January 1, 2014 and December 31, 2017 were retrospectively studied, and 1152 patients with HFS were split into two groups in accordance with the offending vessels. Results954 patients with HFS caused by small vascular compression were classified as Group A. 849 patients got cured immediately after MVD, while delayed resolution was identified in 101 patients. 4 patients were not relieved and 4 were relapsed during the follow-up period. We observed 76 cases of delayed facial paralysis, 7 cases of hearing loss, 2 hoarseness and 3 cases of CSF leakage after surgery. In Group B, 198 patients displayed HFS associated with the vertebral artery (VA). 144 cases were spasm free after surgery and 51 patients had a delayed resolution. 3 patients were not significantly ameliorated and 2 were relapsed during the follow-up period. The major postoperative complications included facial paralysis in 28 patients, hearing loss in 4 and hoarseness and dysphagia in 3. The two groups showed no operative death. ConclusionsFor the patients with HFS related to VA, the delayed cure rate and the incidence of postoperative cranial nerve complications were higher than HFS attributed to small vascular compression. And the two groups were not different in the long-term outcome and the incidence of permanent cranial nerve complications.

Clinical Analysis of Patients with Ipsilateral Coexistence of Hemifacial Spasm and Trigeminal Neuralgia

We sought to analyze the clinical data of patients with ipsilateral coexistence of hemifacial spasm (HFS) and trigeminal neuralgia (TN) and their treatment by microvascular decompression. We retrospectively analyzed the clinical data, imaging examination, offending vessels, surgical methods, and efficacy in 40 patients with ipsilateral coexistence of HFS and TN from January 2009 to January 2018. The posterior cranial fossa was measured using ITK-SNAP 3.0, which counted the cerebrospinal fluid volume on the basis of the region of interest. Preoperative and postoperative status was based on visual analog scale pain scores and Cohen evaluation scale. Preoperative visual analog scale pain scores were 10 for 30 patients, 9 for 8 patients, and 8 for 2 patients. Preoperative Cohen scores were 4 and 3 for 14 and 26 patients, respectively. A big looped vertebral basilar artery (VBA) was identified in the operative field in 18 patients (45%), which was regarded as the direct offending vessel. Postoperative the Barrow Neurological Institute scores were excellent (T= 2) for 30 patients (75%). The HFS completely disappeared in 28 patients (70%). In the follow-up period (12-110 months), no recurrence or any dysfunction of cranial nerves was found. When patients were grouped as per the responsible artery, the mean size of the posterior cranial fossa was significantly lower in the patients with VBA involved, compared with the patients in the noninvolved VBA group. In the VBA-involved group, HFS symptoms first appeared in all 18 patients, while in the non-VBA-involved group, HFS symptoms first appeared in 6/22 patients (P < 0.05). The preoperative Cohen score of the 4 patients in the VBA involved group, as well as that of 22 patients in the non-VBA-involved group, was 3 (P < 0.05). Our study suggests that patients with ipsilateral coexistence of HFS and TN usually have a narrower and smaller posterior fossa and have a large looped VBA as the responsible artery. In addition, patients with VBA involvement often develop HFS symptoms first and are more severe than those with non-vertebral artery involvement. Microvascular decompression is effective for patients with ipsilateral coexistence of HFS and TN.

The value of 3D-TOF-MRA and 3D-FIESTA fusion three-dimensional images in judgment of offending vessel in primary trigeminal neuralgia

Objective To investigate the value of three-dimensional time-flying magnetic resonance angiography (3D-TOF-MRA) and three-dimensional fast imaging employing steady-state acquisition sequence (3D-FIESTA) fusion three-dimensional image in identification of offending vessels of primary trigeminal neuralgia (PTN). Methods A total of 48 patients with PTN who underwent microvascular decompression (MVD) from January 2016 to June 2019 at Department of Neurosurgery, Affiliated Hospital of Qingdao University were retrospectively enrolled into this study. All patients underwent 3D-TOF-MRA and 3D-FIESTA sequence examinations before operation. The 3D-slicer software was used to fuse 3D-TOF-MRA and 3D-FIESTA sequence images and conduct three-dimensional reconstruction. Using MVD as a standard, 3D-TOF-MRA, 3D-FIESTA and fused images were evaluated to determine the offending vessels and their compressive degree on the nerves. Results In MVD, except for 1 patient who had no offending vessel, the other 47 patients had clear offending vessels. The offending vessels were merely arteries in 40 cases, veins in 2, and both arteries and veins in 5. The 3D-TOF-MRA results showed that 5 patients had no offending vessels, and the remaining 43 patients had arteries as offending vessels. The 3D-FIESTA showed that 4 cases had no offending vessels; the offending vessels were arteries in 36 cases, veins in 3 cases, and both arteries and veins in 5 cases. The fused images showed that there were 2 cases without offending vessels; the offending vessels were arteries in 39 cases, veins in 2 cases, and both arteries and veins in 5 cases. Using the MVD as the standard, the accuracy of 3D-TOF-MRA, 3D-FIEST and fusion 3D images for determining the presence/absence offending vessels was 91.7% (44/48), 93.8% (45/48) and 97.9%(45/48), respectively. The accuracy of correct identification of offending vessels by 3D-TOF-MRA, 3D-FIEST and fused images was 54.2% (26/48), 89.6% (43/48) and 93.8% (45/48), respectively. Compared with intraoperative findings, those 3 types of images commonly showed lighter degree of nerve compression, and the differences were statistically significant (all P<0.05). Conclusion Compared with 3D-TOF-MRA and 3D-FIESTA single sequences, the fused images seem to be more accurate in identification of the offending vessels of PTN, which, however, is still associated with underestimation of the nerve compression degree. Key words: Trigeminal neuralgia; Offending vessel; Three-dimensional time-of-flight magnetic resonance angiography; Three-dimensional fast imaging employing steady-state acquisition; Microva-scular decompression

Polytetrafluoroethylene granuloma-associated facial palsy following microvascular decompression.

Microvascular decompression (MVD) may be employed in the management of hemifacial spasm (HFS), wherein a pledget of polytetrafluoroethylene (i.e., Teflon, Chemours, Wilmington DE) is sometimes introduced to separate an offending vessel from the cisternal segment of facial nerve. Rarely, Teflon may cause a granulomatous reaction resulting in nerve palsy. We here present the first case series of facial palsy thought to be secondary to Teflon granuloma following MVD for HFS. A data repository of 1,312 patients with facial palsy was reviewed to identify individuals who had previously undergone MVD for HFS. Data collected include age at time of MVD, age at onset of facial weakness and at presentation, House-Brackmann scores, clinician-graded facial function using the Electronic Facial Paralysis Assessment scale, imaging findings, and therapeutic interventions and outcomes. Six patients meeting criteria were identified. Average time between MVD with Teflon placement and onset of facial weakness was 16.1 (±4.9) years (range 9.3-23.3 years). Initial House-Brackmann scores were as follows: four patients with V/VI and one each with III/VI and IV/VI. Interventions included eyelid weight placement (n = 3), chemodenervation (n = 2), static suspension with tensor fascia latae (n = 2), dynamic reanimation with cranial nerves V to VII transfer (n = 1), and temporalis muscle transfer (n = 1). Teflon granuloma should be considered in the differential diagnosis for patients presenting with new onset facial weakness with a previous history of MVD for HFS. It remains unknown whether early granuloma extirpation is effective. Prompt diagnosis allows consideration of time-sensitive nerve transfer procedures to reanimate facial function. 4 Laryngoscope, 130:1422-1427, 2020.

Penetrating Offending Vessel, The Most Surgically Demanding Type during Microvascular Decompression Surgery in Hemifacial Spasm

Abstract INTRODUCTION Microvascular decompression (MVD) is the most effective and curative treatment option for neurovascular compression syndrome and it is increasingly performed around the world. This study aimed to identify and describe the most technically difficult cases, which were the patients with penetrating offending vessel through the facial nerve, from our experiences and to give surgical tips for the successful MVD. METHODS Surgical records and intraoperative video of hemifacial spasm patients with penetrating offending vessels were reviewed. Interposition of Teflon felt between nerve and vessel was pursued, and neurectomy was avoided as much as possible. RESULTS Five patients with hemifacial spasm were identified as having a penetrating offending vessel through the facial nerve during the last 5 yr of MVD surgery in our institution. Four AICAs and one PICA were the causative vessels. Partial neurectomy was required in 1 patient. During the median follow-up of 6 mo (range, 1-26), all patients were spasm-free. No patients including the one with partial neurectomy were involved in facial palsy or hearing loss. CONCLUSION MVD in HFS patients with penetrating offending vessel through the facial nerve is the most surgically challenging and demands a high surgical skill. Interposition with Teflon felt is effective and neurectomy should be avoided. Intraoperative monitoring of free-running EMG and abnormal muscle response are helpful to decide the extent of surgery.

Wedge-technique for transposition of the vertebral artery in microvascular decompression for hemifacial spasm: technical nuances and surgical outcomes.

Transposition of the vertebral artery (VA) for microvascular decompression for hemifacial spasm (HFS) is often challenging. Various procedures have been proposed to transpose the immobile tortuous VA that cannot be decompressed satisfactorily in the usual manner. A Teflon piece that is cut into a wedge shape was used for transposition of the VA as an offending artery in HFS. One or more wedge-shaped Teflon pieces were simply inserted into a small space between the VA and the brainstem or cerebellar hemisphere without any contact with the entry into the root exit zone (REZ) of the facial nerve. A minimal space can be created by slight mobilization of the VA through rostral or caudal, or in between to the lower cranial nerves (LCNs). In cases of a hypertrophic VA that is hard to mobilize, two or more rigid wedge-shaped Teflon pieces that are coated by fibrin glue can be applied to obtain adequate mobilization of the VA. Moreover, a much harder Teflon bar, which is bent into a V shape, can be used in cases of an immobile VA. Once the VA is transposed to an appropriate position, the Teflon, VA, and contacted surface of the brainstem are fixed together by drops of fibrin glue. The offending arteries were VA-posterior inferior cerebellar artery (PICA) in eight cases, VA in four cases, PICA in four cases, VA-anterior inferior cerebellar artery (AICA) in one case, and AICA in one case. Eighteen cases of HFS were successfully treated using the "Wedge technique." Symptoms disappeared within 2weeks in all patients. Transient facial nerve palsy developed in one case, and transient hoarseness developed in one case. The wedge technique is a simple straight-line maneuver that facilitates sufficient transposition of the VA without any related complications. This technique is also useful for other large offending vessels, such as the anterior or posterior inferior cerebellar arteries, which are hard to mobilize due to the torque of the vessels.

Long-term Outcomes of Microvascular Decompression in the Treatment of Hemifacial Spasm Based on Different Offending Vessels.

To evaluate clinical features, outcomes, and complications in patients with hemifacial spasm (HFS) after microvascular decompression (MVD) of different offending vessels. Clinical data were collected from 362 patients with HFS treated with MVD between January 2013 and January 2014. Patients were divided into five groups based on the offending vessel: A (anterior inferior cerebellar artery [AICA] compression), B (posterior inferior cerebellar artery [PICA] compression), C (AICA plus PICA compression), D (vertebral artery [VA] compression), and E (VA plus small vessel compression). The most common offending vessel was the AICA (51.38%). The most common compression site was the root exit zone. During the follow-up period, the effective rate was 95.48% in group A, 92.15% in group B, 93.10% in group C, 90.14% in group D, and 91.45% in group E. Twenty-nine patients exhibited delayed facial palsy, the most common complication. No statistically significant differences were found in long-term outcomes or MVD-related complications among the study groups. The type of offending vessel was not a prognostic factor for MVD in patients with HFS.

Analysis of the correlation between hemifacial spasm with different offending vessels and essential hypertension

Objective To investigate the correlation between hemifacial spasm (HFS) with different offending vessels and essential hypertension (HTN). Methods A retrospective analysis was conducted on 267 patients of HFS who underwent microvascular decompression (MVD) from November 2015 to April 2017 at Neurosurgery Department of Affiliated Hospital of Logistics University of Chinese People’s Armed Police Force. A total of 88 cases had the comorbidity of HTN (HTN group), and 179 cases had no HTN (non-HTN group). The HFS patients were divided into 4 groups based on the offending vessels: anterior inferior cerebellar artery (AICA) (n=114), posterior inferior cerebellar artery (PICA) (n=85), vertebral artery (VA) (n=49) and multiple artery (MA) groups (n=19). Patients with HTN were also divided into 4 groups according to the offending vessels: HTN-AICA (n=32), HTN-PICA group (n=24), HTN-VA (n=22) and HTN-MA groups (n=10). The classifications as above were to analyze influencing factor of the incidence of HTN among HFS patients and correlation between HFS with different offending vessels and HTN by comparing the clinical data between HTN and non-HTN groups. Results There was no statistical difference in the sex, side of HFS, course of HFS, effect and recurrence at follow-up between HTN and non-HTN groups (all P >0.05). The patient’s age and onset age of HFS in HTN group was significantly higher than those in non-HTN group (both P 0.05), while the side of HFS was statistically different and there were more left-sided than right-sided patients in VA group (P =0.033). Conclusions The HFS onset age is suggested to be an influencing factor of the incidence of HTN. The proportion of HTN was higher in VA and MA groups, and left-sided VA patients are more likely to present comorbidity of HTN. Key words: Hemifacial spasm; Hypertension; Root cause analysis; Offending vessel