Anatomical Study of the Supratentorial Extension for the Retrolabyrinthine Presigmoid Approaches.

BACKGROUND: Supratentorial craniotomy represents the upper part of the combined trans-tentorial or the supra-infratentorial presigmoid approach. In this study, we provide qualitative and quantitative analyses for the supratentorial extension of the presigmoid retrolabyrinthine suprameatal approach (PRSA). METHODS: The infratentorial PRSA followed by the supratentorial extension craniotomy with dividing and removal of the tentorial strip were performed on both sides of 5 injected human cadaver heads (n = 10 sides). Quantitative analysis was performed for the surface area gained (surgical accessibility) by adding the supratentorial craniotomy. Qualitative analysis was performed for the parts of the brainstem, cranial nerves, and vascular structures that became accessible by adding the supratentorial craniotomy. The anatomical obstacles encountered in the added operative corridor were analyzed. RESULTS: The supratentorial extension of PRSA provides an increase in surgical accessibility of 102.65% as compared to the PRSA standalone. The mean surface area of the exposed brainstem is 197.98 (standard deviation: 76.222) and 401.209 (standard deviation: 123.96) for the infratentorial and the combined supra-infratentorial presigmoid approach, respectively. Exposure for parts of III, IV, and V cranial nerves is added after the extension, and the surface area of the outer craniotomy defect has increased by 60.32%. Parts of the basilar, anterior inferior cerebellar, and superior cerebellar arteries are accessible after the supratentorial extension. CONCLUSIONS: The supratentorial extension of PRSA allows access to the supra-trigeminal area of the pons and the lower part of the midbrain. Considering this surgical accessibility and exposure significantly assists in planning such complex approaches while targeting central skull base lesions.

Preservation of cranial nerve function in large and giant trigeminal schwannoma resection: a case series.

BACKGROUND: Trigeminal schwannomas (TSs) are intracranial tumors that can cause significant brainstem compression. TS resection can be challenging because of the risk of new neurologic and cranial nerve deficits, especially with large (≥ 3 cm) or giant (≥ 4 cm) TSs. As prior surgical series include TSs of all sizes, we herein present our clinical experience treating large and giant TSs via microsurgical resection. METHODS: This was a retrospective, single-surgeon case series of adult patients with large or giant TSs treated with microsurgery in 2012-2023. RESULTS: Seven patients underwent microsurgical resection for TSs (1 large, 6 giant; 4 males; mean age 39 ± 14 years). Tumors were classified as type M (middle fossa in the interdural space; 1 case, 14%), type ME (middle fossa with extracranial extension; 3 cases, 43%), type MP (middle and posterior fossae; 2 cases, 29%), or type MPE (middle/posterior fossae and extracranial space; 1 case, 14%). Six patients were treated with a frontotemporal approach (combined with transmastoid craniotomy in the same sitting in one patient and a delayed transmaxillary approach in another), and one patient was treated using an orbitofrontotemporal approach. Gross total resection was achieved in 5 cases (2 near-total resections). Five patients had preoperative facial numbness, and 6 had immediate postoperative facial numbness, including two with worsened or new symptoms. Two patients (28%) demonstrated new non-trigeminal cranial nerve deficits over mean follow-up of 22 months. Overall, 80% of patients with preoperative facial numbness and 83% with facial numbness at any point experienced improvement or resolution during their postoperative course. All patients with preoperative or new postoperative non-trigeminal tumor-related cranial nerve deficits (4/4) experienced improvement or resolution on follow-up. One patient experienced tumor recurrence that has been managed conservatively. CONCLUSIONS: Microsurgical resection of large or giant TSs can be performed with low morbidity and excellent long-term cranial nerve function.

Surgical management of large lower cranial nerves schwannomas: long term results of a less aggressive resection strategy.

In an effort to reduce the high morbidity and life-threatening complications after radical resection in large schwannoma surgery, alternative strategies of nontotal resections have emerged. To evaluate the long term clinical and oncological outcome after lower cranial nerves (LCN) schwannoma surgery operated on with a cranial nerve-sparing technique. Single center retrospective cohort study of 8 consecutive patients harboring LCN schwannomas operated on between March 2005 and October 2021. The mean LCN schwannoma diameter was 33 mm (range 26-51). Seven patients (87,5%) underwent a modified retrosigmoid approach. Three patients underwent gross total resection (37,5%), 3 had received neartotal resection (mean tumor residue 0,25 cc) and subtotal resection in 2 patients who presented with an extracranial extension of the tumor (mean tumor residue 2,44 cc). Both patients had received upfront additional GKRS. The three patients who presented with preoperative CN IX & X injuries recovered within 6 months after surgery. All of the five patients freed from any preoperative CNs IX & X symptoms experienced transient (80%) or definitive (one patient) disturbances after surgery. They all improved within 6 months but one who required long term gastrostomy feeding tube. This patient harbored a schwannoma originating from the glossopharyngeal nerve, which could not be anatomically preserved during surgery. Tumor control was achieved in 100% of cases with a mean follow-up of 91 months. LCN schwannomas could be surgically removed through a less aggressive non-radical resection strategy with acceptable functional results and excellent tumor control.

[Developmental History of Microvascular Decompression Surgery for Cranial Nerve Dysfunction].

Trigeminal neuralgia is characterized by severe lancinating pain in the face and hemifacial spasms displayed by continuous facial muscle twitching, which may impair a patient's quality of life. Before 1960, in the United States of America, the treatment of such symptoms was only partial rhizotomy of the cranial nerves, which resulted in postoperative complications.1, 2) Afterwards, in the late 1960s, it became evident that the etiology of symptoms was an elicited arterial compression of the cranial nerves at the "Root Entry/Exit zone." Microvascular decompression(MVD)was introduced and finally became largely popularized by Gardner and Jannetta et al.3, 4) In 1978, at the Neurosurgical Meeting in New York, I incidentally witnessed slides of MVD proposed by Jannetta, which gave me a big surprise since we were then treating such patients by old-fashioned rhizotomy. Despite much ignorance displayed even in the neurosurgical meeting, I started MVD in 1980.5) In addition, in 1998 we held an Annual Meeting of the Japan Society for Microvascular Decompression Surgery, which has become more active in the fields of microsurgical techniques, diagnosis, monitoring, and long-term follow-up studies.6-8) MVD is a functional neurosurgery and satisfactory results should entail a complete and permanent cure of symptoms without any postoperative sequelae. This makes MVD a sustainable surgery.

[Efficacy of CT-guided partial radiofrequency ablation of bilateral responsible cranial nerves in the treatment of Meige syndrome].

Objective: To evaluate the efficacy of CT-guided partial radiofrequency ablation of bilateral responsible cranial nerves in the treatment of Meige syndrome. Methods: The Clinical data of 56 patients with Meige syndrome in the Department of Pain Medicine, Affiliated Hospital of Jiaxing University from June 2019 to January 2023 were retrospectively analyzed [19 males and 37 females, aged 42-76 (58.6±8.3) years], including 51 cases of blepharospasm, 3 cases of oromandibular dystonia and 2 cases of blepharospasm concomitant with oromandibular dystonia. CT-guided partial radiofrequency ablation of bilateral responsible cranial nerves was performed on different types of Meige syndrome. And the efficacy and complications of the technique were observed. Results: Fifty-one patients with blepharospasm Meige syndrome underwent CT-guided radiofrequency of facial nerve through bilateral stylomastoid foramen punctures, the symptoms of blepharospasm disappeared completely, leaving bilateral mild and moderate facial paralysis symptoms. Three patients with oral-mandibular dystonia underwent CT-guided radiofrequency therapy by bilateral foramen ovale puncture of mandibular branches of trigeminal nerve, masticatory muscle spasm disappeared, the patients had no difficulty opening the mouth, and the skin numbness in bilateral mandibular nerve innervation area was left. Two cases of Meige syndrome with blepharospasm concomitant with oromandibular dystonia were treated by radiofrequency of facial nerve and mandibular branch of trigeminal nerve, and all symptoms disappeared. The patients were followed up for 1-44 months after the operation, and the symptoms of mild and moderate facial paralysis disappeared at (3.2±0.8) months after the operation, but the numbness did not disappear. Three patients with blepharospasm recurred at the 14, 18 and 22 months after the operation, respectively, while the rest cases did not recur. Conclusions: According to different types of Meige syndrome, CT-guided partial radiofrequency ablation of responsible cranial nerves can effectively treat the corresponding type of Meige syndrome. The complications are only mild and moderate facial paralysis which can be recovered, and/or skin numbness in the mandibular region.

A Three-Dimensional Anterior and Middle Cranial Fossa Model for Skull Base Surgical Training with Two Layers of the Colored Dura Mater.

BACKGROUND: Adequate epidural procedures and anatomical knowledge are essential for the technical success of skull base surgery. We evaluated the usefulness of our three-dimensional (3D) model of the anterior and middle cranial fossa as a learning tool in improving knowledge of anatomy and surgical approaches, including skull base drilling and dura matter peeling techniques. METHODS: Using a 3D printer, a bone model of the anterior and middle cranial fossa was created based on multi-detector row computed tomography data, incorporating artificial cranial nerves, blood vessels, and dura mater. The artificial dura mater was painted using different colors, with 2 pieces glued together to allow for the simulation of peeling the temporal dura propria from the lateral wall of the cavernous sinus. Two experts in skull base surgery and 1 trainee surgeon operated on this model and 12 expert skull base surgeons watched the operation video to evaluate this model subtlety on a scale of 1 to 5. RESULTS: A total of 15 neurosurgeons, 14 of whom were skull base surgery expert, evaluated, scoring 4 or higher on most of the items. The experience of dural dissection and 3D positioning of important structures, including cranial nerves and blood vessels, was similar to that in actual surgery. CONCLUSIONS: This model was designed to facilitate teaching anatomical knowledge and essential epidural procedure-related skills. It was shown to be useful for teaching essential elements of skull-base surgery.

[Monitoring of the Floor of the 4th Ventricle for Brainstem Surgery].

The brainstem is densely aggregated with important cranial nerve nuclei and nerve tracts. Surgery in this area is, therefore, risky. Not only anatomical knowledge but also electrophysiological monitoring is essential for brainstem surgery. The facial colliculus, obex, striae medullares, and medial sulcus are important visual anatomical landmarks at the floor of the 4th ventricle. As cranial nerve nuclei and nerve tracts deviate by lesion, it is important to have a firm image of the cranial nerve nuclei and nerve tracts before making an incision in the brainstem. The entry zone into the brainstem is selected where the parenchyma is the thinnest due to the lesions. The suprafacial or infrafacial triangle is often used as an incision site for the floor of the 4th ventricle. In this article, we introduce the electromyographic method of observing the external rectus muscle; orbicularis oculi muscle; orbicularis oris muscle; and tongue; and two cases in which monitoring was used(the pons and medulla cavernoma cases). By examining surgical indications in this way it may be possible to improve the safety of such operations.

Correlation of Preoperative High-Resolution Neurovascular Imaging and Surgical Success in Neurovascular Compression Syndromes.

BACKGROUND: Neurovascular compression syndromes (NVCSs) are a group of neurological disorders characterized by compression of a cranial nerve and include trigeminal neuralgia (TN), hemifacial spasm, geniculate neuralgia, glossopharyngeal neuralgia, vestibular paroxysmia, and trochlear palsy. The European Academy of Neurology recommends constructive interference in steady-state/fast imaging employing steady-state (CISS/FIESTA) magnetic resonance imaging (MRI) in the evaluation of medically intractable TN, but similar recommendations do not exist for the remaining NVCSs. METHODS: We conducted a retrospective chart review of 300 patients with an NVCS who underwent microvascular decompression (MVD) by a single neurosurgeon from 2004 to 2021. Data were collected on preoperative diagnosis, pre- and postoperative symptoms, presence/absence of preoperative high-spatial-resolution CISS/FIESTA MRI, and intraoperative findings. Rates of symptomatic improvement were used as a correlate of surgical success. RESULTS: The rate of symptomatic improvement in the patients with a preoperative CISS/FIESTA MRI was 5.8% greater than those without preoperative high-spatial-resolution neuroimaging (98.8% vs. 93%, respectively; P = 0.008). Stratified by diagnosis, patients with TN had the greatest difference in surgical success between the 2 groups (99.3% vs. 92.9%, n = 268; P = 0.006). No statistically significant differences were observed in the other NVCSs, although positive trends were noted. CONCLUSIONS: Preoperative CISS/FIESTA MRI correlated with greater rates of surgical success in cases of medically intractable TN; however, definitive conclusions could not be made regarding the remaining NVCSs. We support the recommendation that this imaging modality be included as part of the standard of practice for the evaluation and management of TN and encourage future studies to further elucidate this relationship for the less common NVCSs using a larger cohort.

Quantitative Comparative Analysis of the Endoscope-Assisted Expanded Retrosigmoid Approach and the Far-Lateral Approach to the Inframeatal Area: An Anatomic Study With Surgical Implications.

BACKGROUND: The inframeatal area (IFMA) is a complex anatomic region of the posterior cranial fossa. Given its deep-seated location, tumors involving the IFMA represent a surgical challenge. OBJECTIVE: To objectively compare the endoscope-assisted expanded retrosigmoid approach (ERSA) and the far-lateral supracondylar transtubercular approach (FLTA) to address the IFMA. METHODS: Anatomic dissections were performed on 5 cadaveric heads (10 sides). The ERSAs were performed before and after the FLTAs. The surgical exposure, surgical freedom, and angles of attack to the IFMA were measured and compared for each approach. In addition, 2 illustrative clinical cases are reported. RESULTS: Compared with FLTA, ERSA yielded a nonsignificantly smaller mean area of exposure, whereas FLTA provided a significantly larger mean area of surgical freedom, compared with ERSA ( P = .002). The mean horizontal and vertical angles of attack were significantly different between the approaches. In the vertical plane, FLTA yielded the broadest angle of attack at the root entry zone of the lower cranial nerves (CN; P < .004), whereas ERSA did so at the dural entry zone of CN VII/VIII ( P = .006). In the horizontal plane, FLTA achieved its broadest angle of attack at the root entry zone of the lower CNs ( P = 1.83) while ERSA at the dural entry zone of CN VII/VIII ( P = .37). CONCLUSION: ERSA and FLTA granted a comparable exposure with the IFMA. Although FLTA may afford a larger area of surgical freedom, ERSA may be a suitable alternative to approach the IFMA, particularly to reach the most medial and superior aspects of this region. Conversely, FLTA may facilitate access to more caudally targets.

Glossopharyngeal neuralgia as initial symptom in combined hyperactive dysfunction syndrome: case report.

OBJECTIVES: Hyperactive dysfunction syndrome (HDS) is defined as symptoms arising from overactivities in cranial nerves, like trigeminal neuralgia (TN), hemifacial spasm (HFS), and glossopharyngeal neuralgia (GPN). A combination of these cranial nerve neuralgias, that might or might not occur in one or both sides, either synchronously, or metachronously is called combined hyperactive dysfunction syndrome (CHDS). CASE PRESENTATION: We presented a 73 years-old male patient with CHDS presenting with GPN as the initial symptom, with total relief from GPN, TN, and HFS after microvascular decompression. Up to date, only nine patients have been reported in the literature with symptomatic. CONCLUSIONS: TN-HFS-GPN. Our case is the first case with GPN as the initial symptom. The combination of arterial and venous origin of the offending vessels makes the case picturesage.

Temporary 6TH cranial nerve paralysis after accidental durotomy in endoscopic disc surgery.

We present a unique case of 6th nerve palsy following accidental durotomy in endoscopic lumbar spine surgery, which has not been reported in the literature before. A 72- year-old female patient was admitted to our outpatient clinic complaining of right leg pain for 6 months. A 4/5 motor paresis was observed on her right toe with a positive Lasegue test at 45°. On her magnetic resonance imaging (MRI), a L5-S1 disc herniation was detected. The patient was planned for percutaneous endoscopic interlaminar disc surgery. The extruded disc was adherent to the dura. During removal, a dural tear was observed. She was relieved of her right leg pain immediately after surgery, but after 30 min postoperatively, she complained of double vision with left abducens nerve paralysis. On cranial MRI, no abnormality could be observed. Intravenous fluids were administered and the paralysis resolved on the postoperative 24th hour. The patient was discharged from the hospital and did not show any complaints on her follow-ups. A 6th nerve palsy can be caused due to alterations of intracranial pressure or mechanic injury. We believe that the durotomy following removing of the disc fragment caused a rapid drainage of CSF, leading to intracranial hypotension and injury of the abducens nerve. Intracranial pressure should be monitored perioperatively and brisk deteriorations has to result in immediate finishing of the surgery to avoid further secondary damage.

[Dysfunctions and anatomical relationships of cranial nerves in epidermoids of the cerebellopontine angle]. / Disfunktsii i anatomicheskie vzaimootnosheniya kranial'nykh nervov pri epidermoidakh mostomozzhechkovogo ugla.

OBJECTIVE: To evaluate the correlation of neurological symptoms with anatomical relationships of cranial nerves, lesions and vessels in patients with epidermoids of the cerebellopontine angle. MATERIAL AND METHODS: We analyzed neurological symptoms, magnetic resonance data, intraoperative findings and postoperative functional outcomes in 25 patients (14 females and 11 males aged 22-77 years) with epidermoids of the cerebellopontine angle. RESULTS: Cranial nerve dysfunctions were noted in 15 patients. Involvement of cochlear (n=9) and trigeminal (9 cases including 4 ones with sensory impairment and 5 patients with neuralgia) nerves was the most common. There were 10 patients with ataxia, hemiparesis and seizures without cranial nerve dysfunction. In 15 patients, epidermoids spread to supratentorial space and contralateral cerebellopontine angle. Lesion-induced brainstem compression was found in 22 cases. Cranial nerves and cerebellar arteries were partially or completely enclosed by lesion in all cases. Severe compression and dislocation of the nerve root entry/exit zone were found in all cases. One patient with trigeminal neuralgia had vascular compression of trigeminal nerve caused by superior cerebellar artery. Total resection was achieved in 16 patients. Small capsule remnants were left on vessels, nerves or brainstem in 9 patients. Postoperative complete or partial restoration of cranial nerve functions was noted in 11 cases. Deterioration of preoperative neurological deficit in 4 patients and postoperative neurological symptoms de novo in 3 patients were temporary. CONCLUSION: Cranial nerve dysfunctions are caused by compression of the nerve root entry/exit zones by epidermoids of the cerebellopontine angle. Surgical intervention is effective in alleviating symptoms of cranial neuropathy and brainstem compression. Vascular decompression should be performed in patients with trigeminal neuralgia.

Deep Learning Based Real-Time Semantic Segmentation of Cerebral Vessels and Cranial Nerves in Microvascular Decompression Scenes.

Automatic extraction of cerebral vessels and cranial nerves has important clinical value in the treatment of trigeminal neuralgia (TGN) and hemifacial spasm (HFS). However, because of the great similarity between different cerebral vessels and between different cranial nerves, it is challenging to segment cerebral vessels and cranial nerves in real time on the basis of true-color microvascular decompression (MVD) images. In this paper, we propose a lightweight, fast semantic segmentation Microvascular Decompression Network (MVDNet) for MVD scenarios which achieves a good trade-off between segmentation accuracy and speed. Specifically, we designed a Light Asymmetric Bottleneck (LAB) module in the encoder to encode context features. A Feature Fusion Module (FFM) was introduced into the decoder to effectively combine high-level semantic features and underlying spatial details. The proposed network has no pretrained model, fewer parameters, and a fast inference speed. Specifically, MVDNet achieved 76.59% mIoU on the MVD test set, has 0.72 M parameters, and has a 137 FPS speed using a single GTX 2080Ti card.

[Surgical Anatomy of the Cavernous Sinus, Parasellar Region, and Orbit].

The cavernous sinus, para-sellar region, and orbit have intricately intertwined cranial nerves, blood vessels, and dura mater. In surgery, anatomical understanding is very important. Recognizing the location(depth)of the cranial nerves running on the lateral and upper wall of the cavernous sinus is vital and is directly linked to postoperative complications. In addition, understanding the dural ring in the clinoid segment of the internal carotid artery is important. The periosteum on the upper surface of the anterior clinoid is the distal dural ring of the internal carotid artery, and the periosteum on the lower surface is the proximal dural ring. The orbit is filled with adipose tissue and is completely different from other intracranial parts. However, understanding the anatomy from the orbital apex to the superior orbital fissure is important in the pterional approach.

Monitoring surgery around the cranial nerves.

Intraoperative neurophysiologic monitoring (IONM) of cranial nerve (CN) function is an essential component in multimodality monitoring of surgical procedures where CNs are at risk for injury. In most cases, IONM consists of localizing and mapping CNs and their pathways, and monitoring of CN motor function during surgery. However, CN VIII, which has no motor function, and is at risk for injury in many surgical procedures, can be easily and accurately monitored using brainstem auditory evoked potentials. For motor CNs, the literature is clear that function can be safely and adequately performed using basic electromyographic (EMG) techniques, such as recording of continuous EMG activity and electrically evoked compound muscle actions potentials. Newer techniques, such as corticobulbar motor evoked potentials and reflex studies, show good potential for a greater degree of functional assessment but require further study to determine their clinical utility. EMG remains the basic clinical neurophysiologic technique with the greatest clinical research supporting its utility in IONM of motor CN function and should be used as part of a comprehensive multimodality IONM protocol. Understanding the physiologic basis of EMG and the changes associated with altered motor function will allow the practitioner to alter surgical course to prevent injury and improve patient safety.

Surgical Resolution of Trigeminal Neuralgia Complicating Vestibular Schwannoma Removal.

This work illustrates the case of surgical treatment of trigeminal neuralgia (TN), as a tardive complication after vestibular schwannoma (VS) removal (Koos III, Figure 1), in a female patient. After VS surgery, the postoperative computed tomography scan did not show any significant complication, although a thin blood clot was present in the surgical bed (Figure 2). However, 3 months later, our patient developed a TN involving the territories V2-V3. Medical therapies were ineffective. Several magnetic resonance imaging scans confirmed a left dislocation of the brainstem (Figures 3 and 4), probably due to the previous clot retraction. The anatomic-functional preservation of the left Tn was documented using the laser-evoked potentials. Fifteen months after surgery, our patient underwent a second operation aimed at exploring the Tn territory, with the use of the intraoperative monitoring and mapping the fifth and seventh cranial nerves. A neurovascular conflict, caused by scar tissue involving the superior cerebellar artery, a small vein, and the Tn, was detected and surgically solved (Figure 5). Postoperative analgesic treatment was progressively reduced and suspended. The case is illustrated and explained in the Video 1. The paucity of cases reported in the literature lead us to think that TN as complication of VS removal is underestimated because it may be responsive to medical treatment. Laser-evoked potentials may be useful to study the integrity of the Tn, ensuring that no anatomic damage has been done during surgery. On the basis of our experience, surgery can be an effective treatment option when TN is not responsive to medical therapy and the anatomic-functional integrity of the Tn has been preserved.

Preservation of Cranial Nerves Function in Glomus Jugulare Surgery: 2-Dimensional Operative Video.

Owing to their invasive character, extreme vascularity, and critical location, glomus jugulare tumors present a formidable challenge. Techniques have been developed for safe and successful removal of even giant glomus paragangliomas.1-3 Preoperative evaluation including genetic, hormonal, and multiplicity workup4 has enhanced the safety of surgical management, as did modern preoperative embolization by eliminating excessive blood loss.5 Despite these advancements, surgical outcomes of glomus jugulare remain haunted by cranial nerve dysfunction such as facial nerve palsies and hearing loss, with lower cranial nerves dysfunction being the most morbid. These can be avoided by technical maneuvers to preserve the cranial nerves. The external ear canal is not closed to maintain conductive hearing. The facial nerve is not transpositioned and kept inside a bony protective canal. Cranial nerves IX, X, and XI are the most vulnerable because they pass through the jugular foramen ventral to the venous bulb wall. They are preserved by intrabulbar dissection that maintains a protective segment of the venous wall over the nerves. By mastering the anatomy of the upper neck, meticulous dissection is performed to preserve the course of IX, X, XI, and XII.6,7 Ligation of the jugular vein is delayed until the tumor is totally isolated to avoid diffuse bleeding.7 We present the case of a 60-yr-old woman with a glomus jugulare tumor with intradural, extradural, and cervical extension. The technical nuances of cranial nerves preservation are demonstrated. The patient consented to the procedure and publication of her images. Images at 2:12, 2:50, and 3:09 from Al-Mefty and Teixeira,6 with permission from JNSPG.

Microvascular decompression for hemifacial spasm involving the vertebral artery.

OBJECTIVE: Microvascular decompression (MVD) has become an accepted treatment modality for the vertebral artery (VA)-involved hemifacial spasm (HFS). The aim of this retrospective study was to evaluate clinical and surgical outcomes of HFS patients undergoing MVD and surgical and cranial nerve complications and investigate reasonable transposition procedures for two different anatomic variations of VA. METHODS: Between January and December 2018, 109 patients underwent first MVD for HFS involving VA at Nanjing Drum Tower Hospital. Based on whether the VA could be moved ventrally at the lower cranial nerves (LCNs) level, patients were assigned to Group A (movable VA, n = 72) or B (unmovable VA, n = 37), and clinical and surgical outcomes and complications on the day of post-surgery and during follow-up were assessed. All patients were followed up ranging from 17 to 24 months with a mean follow-up period of 21 months. RESULTS: After a mean follow-up of 21 months, the total cure rate significantly decreased in all patients compared to that achieved on the day of surgery, and Group A patients exhibited a higher cure rate versus Group B (93.1% vs. 75.7%, P = 0.015). Group B patients with unmovable VA revealed both higher incidence of surgical complications (45.9% vs. 15.3%, P = 0.001) and frequency of bilateral VA compression (27% vs. 8.3%, P = 0.009) versus Group A. No significant difference was observed in long-term cranial nerve complications. CONCLUSIONS: VA-involved HFS can benefit from MVD strategies after preoperative assessment of VA compression. HFS patients with movable VA may receive better long-term efficacy and fewer complications. A Teflon bridge wedged between the distal VA and medulla gives rise to adequate space for decompression surgery.

Comparison of Lower Cranial Nerve Function Between Tympanojugular Paraganglioma Class C1/C2 With and Without Intracranial Extension: A Four-Decade Experience.

OBJECTIVE: To compare preoperative and postoperative lower cranial nerve (LCN) function between Class C1 and C2 tympanojugular paraganglioma (TJP) with/without intracranial intradural (Di)/extradural (De) extensions, according to the experience of a single surgeon over four decades. STUDY DESIGN: Retrospective review. SETTING: Quaternary referral center for otology and skull base surgery. MATERIAL AND METHODS: A chart review was conducted of all the patients operated for C1/C2 TJPs from September 1983 to December 2018. The tumors were classified as: Limited-Group (C1/C2 without Di/De extensions) and Extended-Group (C1/C2 with Di/De extensions). RESULTS: Of 159 patients, 107 (67.3%) were women; the mean age at surgery was 46.5 years. The Limited-Group (56.6%) comprised C1 (41.1%) and C2 (58.9%) tumors; the Extended-Group (43.4%) comprised C1+Di/De (14.5%) and C2+Di/De (85.5%) tumors. The prevalence of preoperative LCN palsy was 11.9 times higher in Extended than Limited tumors: 61.9% versus 4.9% (p < 0.05). The risk for postoperative LCN palsy was 4.7 times greater in Extended than Limited tumors: 29.2% versus 12.9%, p = 0.01. CONCLUSION: Especially in younger patients, complete removal of Limited C1/C2 tumors, before they extend intracranially, reduces the risk of dysfunctionality of LCNs and the burden of residual tumor. The incidence of new tumors increased over four decades. However, new-postoperative LCN palsy did not occur in any Limited C1/C2 tumors operated after the year 2000, and declined to less than 10% of Extended C1/C2 tumors.