Endoscopic Anatomy of the Zygomatic Nerve: Implications for the Endoscopic Transmaxillary Approach

Background Understanding the anatomic features of the zygomatic nerve is critical for performing the endoscopic transmaxillary approach properly. Injury to the zygomatic nerve can result in facial numbness and corneal problems. Objective To evaluate the surgical anatomy of the zygomatic nerve and its segments from an endoscopic endonasal perspective for clinical implications of performing the endoscopic transmaxillary approach. Methods The origin, course, length, and segments of the zygomatic nerve were studied in four specimens from an endonasal perspective. Results The zygomatic nerve arises 4.1 ± 1.7 mm from the foramen rotundum of the maxillary nerve in the superolateral pterygopalatine fossa (PPF). According to its anatomic region in endonasal endoscopic surgery, we divided the zygomatic nerve into two segments: the PPF segment, from origin to the point of entry under Muller's muscle, which runs superolaterally to the inferior orbital fissure (IOF) (length, 4.6 ± 1.3 mm), and the IOF segment, starting at the entry point in Muller's muscle and terminating at the exit point in the IOF, which travels between Muller's muscle and the great wing of the sphenoid bone (length, 19.6 ± 3.6 mm). In the transmaxillary approach, the zygomatic nerve is a critical landmark in the superolateral PPF. Conclusion The zygomatic nerve travels in the PPF and the IOF; better visualization and preservation of this nerve during endonasal endoscopic surgery are crucial for successful outcomes.

Facial Paresthesia, a Rare Manifestation of Hereditary Neuropathy With Liability to Pressure Palsies: A Case Report

Trigeminal sensory neuropathy can be caused by a variety of conditions, including local, traumatic, iatrogenic, or systemic causes. Diagnosis and management remain a challenge for maxillofacial surgeons and neurologists. Therefore, a good clinical examination and objective tests and imaging are needed when diagnosing patients who present with facial numbness. We present a case with spontaneous episodes of facial paresthesia. He was diagnosed with hereditary neuropathy with liability to pressure palsies (HNPP), a rare condition that affects the peripheral nerves. Only a few case reports that describe involvement of the cranial nerves in patients with HNPP were found in the literature, and facial paresthesia has not been previously reported.

Diplopia, Orbital Pain, and Vision Loss in a Middle-Aged Woman

A 59-year-old woman with type 2 diabetes had development of fluctuating, binocular, painless diplopia. She experienced headache, orbital pain, facial numbness, and progressive vision loss in the left eye. Her left eye vision worsened. Magnetic resonance imaging of the brain and orbit showed bilateral optic nerve enhancement. She started treatment with empiric intravenous corticosteroids for presumed optic neuritis, which resulted in transient improvement. Subsequently, her vision worsened to no light perception in the left eye, and she had fluctuating vision loss in the right eye. Cerebrospinal fluid evaluation was performed because the patient’s fluctuating diplopia and facial numbness suggested involvement of multiple cranial nerves. The cerebrospinal fluid showed white blood cells with lymphocytes, increased protein concentration, and negative oligoclonal bands and cytologic findings. Repeated brain magnetic resonance imaging 1 year after symptom onset showed persistent bilateral (left > right) optic nerve enhancement along with oculomotor nerve and left midbrain enhancement. We recommended left optic nerve biopsy to obtain the diagnosis and attempt to preserve vision in the threatened right eye. Because the patient had no light perception in the left eye for 5 months, with significant pallor of the optic nerve, it was unlikely that she had salvageable left eye vision. Furthermore, there was concern for lymphomatous infiltration of the optic nerve. Confirmation of a lymphoma diagnosis would be critical for initiation of specific chemotherapy. The pathologic analysis identified noncaseating granulomas. The finding of noncaseating granulomas was consistent with neurosarcoidosis infiltrating the left optic nerve. The patient was treated with intravenous methylprednisolone followed by prolonged, high-dose, oral corticosteroids along with corticosteroid prophylaxis of calcium, vitamin D, a proton-pump inhibitor, and dapsone for Pneumocystis prophylaxis Sarcoidosis is a systemic disease of unknown cause that can occur anywhere in the body but most commonly involves the lungs. The pathologic hallmark of sarcoidosis is noncaseating granulomas.

Linear accelerator–based radiosurgery for trigeminal neuralgia: comparative outcomes of frame-based and mask-based techniques

OBJECTIVE Precise and accurate targeting is critical to optimize outcomes after stereotactic radiosurgery (SRS) for trigeminal neuralgia (TN). The aim of this study was to compare the outcomes after SRS for TN in which two different techniques were used: mask-based 4-mm cone versus frame-based 5-mm cone. METHODS The authors performed a retrospective review of patients who underwent SRS for TN at their institution between 1996 and 2019. The Barrow Neurological Institute (BNI) pain score and facial hypesthesia scale were used to evaluate pain relief and facial numbness. RESULTS A total of 234 patients were included in this study; the mean age was 67 years. In 97 patients (41.5%) radiation was collimated by a mask-based 4-mm cone, whereas a frame-based 5-mm cone was used in the remaining 137 patients (58.5%). The initial adequate pain control rate (BNI I–III) was 93.4% in the frame-based 5-mm group, compared to 87.6% in the mask-based 4-mm group. This difference between groups lasted, with an adequate pain control rate at ≥ 24 months of 89.9% and 77.8%, respectively. Pain relief was significantly different between groups from initial response until the last follow-up (≥ 24 months, p = 0.02). A new, permanent facial hypesthesia occurred in 30.3% of patients (33.6% in the frame-based 5-mm group vs 25.8% in the mask-based 4-mm group). However, no significant association between the BNI facial hypesthesia score and groups was found. Pain recurrence occurred earlier (median time to recurrence 12 months vs 29 months, p = 0.016) and more frequently (38.1% vs 20.4%, p = 0.003) in the mask-based 4-mm than in the frame-based 5-mm group. CONCLUSIONS Frame-based 5-mm collimator SRS for TN resulted in a better long-term pain relief with similar toxicity profiles to that seen with mask-based 4-mm collimator SRS.

Comparison of Microvascular Decompression and Two Isocenters Gamma Knife for the Treatment of Trigeminal Neuralgia Caused by Vertebrobasilar Dolichoectasia

Background: Vertebrobasilar dolichoectasia (VBD) is one of the rare causes of trigeminal neuralgia (TN). The common surgical treatments for patients with TN caused by VBD (VBD-TN) are microvascular decompression (MVD) and Gamma Knife radiosurgery (GKRS). However, the therapeutic effects of the two methods have not been clinically compared, so this study was performed to evaluate the treatment outcomes of MVD and GKRS for patients with VBD-TN.Methods: The retrospective study was performed from March 2011 to March 2019 in Wuhan Union Hospital. A total of 80 patients diagnosed with VBD-TN were included in this study, and they were divided into the MVD group (n = 46) and GKRS group (n = 34) according to the surgical methods. The imaging data, intraoperative findings, treatment outcomes, and complications of the two groups were analyzed and compared. Meanwhile, the influencing factors of the treatment effect are also explored on the two groups.Results: Patients who underwent MVD were younger than patients who underwent GKRS (median ages were 61.1 and 65.4 years old, respectively, p = 0.03). The median follow-up was 61.1 months for the MVD group and 56.8 months for the GKRS group. The favorable outcomes [Barrow Neurological Institute (BNI) pain score, BNI scores I–II] occurred in 97.8% of patients treated with MVD and in 78.9% of patients treated with GKRS (p = 0.009). The favorable outcomes in the percentage of patients after MVD 1, 3, 5, and 7 years were 95.7, 85.1, 74.2, and 74.2%, respectively, whereas the corresponding percentages after GKRS were 76.5, 66.2, 56.6, and 47.2%, respectively (p = 0.031). The postoperative complications (except facial numbness) in the MVD group were higher than those in the GKRS group (p = 0.036), but the incidence of new and worsening facial numbness was lower in the GKRS group (p < 0.001).Conclusions: MVD is superior to GKRS in obtaining and maintaining favorable outcomes for patients with VBD-TN, but it also comes with more complications other than facial numbness. Thus, the treatment program can be tailored to a patient's unique condition and wishes.

Cystic Lesions in Giant Intraventricular Meningioma: Cases Report

Background: Giant meningioma stemming from intraventricular zone has been reported to be extremely few. Two cases of supersize (>8 cm) intraventricular meningiomas presenting with cystic lesions and their clinical characteristics were collected in our study.Case description: One patient was a 56-year-old man who hospitalized for blunt headache and weakness of right lower limb along with defect of right visual field for 12 months. The other patient is a 22-year-old lady presented with slight headache accompanied with right facial numbness for one week. Computed tomography and magnetic resonance imaging of both patients revealed a giant heterogeneous, enhancing tumor mainly in the left trigonum with a low-density or hypointense cystic lesions located within or around the tumor. Total resection was performed via a transcortical approach in both cases. The pathological and immunohistochemical staining indicated fibroblastic meningioma (case one) and atypical meningioma (case two) respectively. Postoperatively, both of patients recovered free from episodes of symptoms and imaging examinations confirmed no evidence of regrowth of the meningioma during an average 24 months follow-up. Conclusions: Cystic lesions may indicate the histopathologic malignancy of intraventricular meningioma. Transcortical approach through the posterior temporal lobe or the parieto-occipital lobe is an effective technology for giant intraventricular meningiomas.

Transcondylar Approach for Resection of Medullary Cavernous Malformation: 2-Dimensional Operative Video

Cavernous malformations located within the brainstem present with a high rate of neurological symptoms and carry a more aggressive course in both pediatric and adult populations.1,2 Cavernomas within the medulla are the rarest form, representing only 5% of all brainstem lesions.3 Repeated hemorrhage of brainstem cavernomas is associated with significant and cumulative neurological deficits and thus requires treatment.4 Microsurgical resection has become the optimal mode of treatment with the aim of resecting the live malformation and not merely the multiaged, organized hematoma.4 This is best achieved by approaching the cavernoma at the location where it projects to the surface and entering the lesion through a safe brainstem anatomic zone. For ventrally located lesions in the medulla, a transcondylar skull base approach provides a direct trajectory to the entry zone through a short surgical distance without the need to manipulate or retract neurovascular structures.5-8 Neuronavigation and intraoperative neurophysiological monitoring of somatosensory evoked potential, motor, and lower cranial nerves are adjuncts to increase patient safety. Radiosurgery for the treatment of brainstem cavernous malformations has been proposed; however, it demonstrates high risk and variable and often poor response rates.9 We present a surgical video demonstrating the transcondylar approach and resection of a medullary cavernoma in a 54-yr-old woman who has had multiple known prior hemorrhages and presented with a new onset of facial numbness and weakness, ataxia, and left body sensory loss. The patient consented to surgery and to photograph publication. Images at 1:28, 1:43 (left), 2:02 from Al-Mefty O, Operative Atlas of Meningiomas, © LWW, 1997,5 with permission. Images at 1:43 (right) from Arnautovic et al,8 with permission from JNSPG.

Cavum trigeminale cephalocele associated with intracranial hypertension in an 18-month-old child: illustrative case

BACKGROUND Cavum trigeminale cephaloceles (CTCs) are characterized by a cystic appearance and extension of the posterolateral aspect of Meckel’s cave into the superomedial portion of the petrous apex. A possible mechanism is a transient or sustained increase of intracranial pressure transmitted to Meckel’s cave, leading to its secondary herniation, in the presence of predisposing local factors. The majority of CTCs are incidental findings. Among symptomatic cases, headache, trigeminal neuralgia, cerebrospinal fluid leak, vertigo, ataxia, facial numbness, hearing loss, diplopia, and other visual disturbances have been described. OBSERVATIONS The authors describe a case of an 18-month-old male patient referred to their hospital with drowsiness, vomiting, left cranial nerve VI palsy, and papilledema. Neuroradiological investigation revealed the presence of a CTC with a swollen aspect of the left pontine hemisection and indirect signs of intracranial hypertension. The patient was managed with implantation of a ventriculoperitoneal shunt. LESSONS CTCs are rare lesions that are difficult to recognize on neuroimaging, in which they can be mistaken for tumoral or inflammatory lesions. The most frequent asymptomatic forms should be considered as “leave-me-alone” lesions. In cases of intracranial hypertension, according to a supposed theory on the origin of CTCs, the authors recommend treating only the intracranial hypertension instead of performing more invasive surgical procedures, especially in pediatric patients.

Internal Neurolysis for the Treatment of Trigeminal Neuralgia: Systematic Review

Introduction Trigeminal neuralgia remains a challenging disease with significant debilitating symptoms and variable efficacy in terms of treatment options, namely microvascular decompression (MVD), stereotactic radiosurgery (SRS), and percutaneous rhizotomy. Internal neurolysis (IN) is an alternative treatment that may be provide patient benefit but has limited understanding. We performed a systematic review of IN treatment of trigeminal neuralgia. Methods Studies from 2000 to 2021 that assessed IN in trigeminal neuralgia were aggregated and independently reviewed. Weighted averages for demographics, outcomes and complications were generated. Results A total of 520 patients in 12 studies were identified with 384 who underwent IN (mean age 53.8 years, range 46-61.4 years). A mean follow-up time of 36.5 months (range 12-90 months) was seen. Preoperative symptoms were present for about 55.0 months before treatment and pain was predominantly in V2/3 (26.8%) followed by other distributions. An excellent to good outcome (Barrow Neurological Institute Pain Score [BNI-PS] I-III) was seen in 83.7% of patients (range 72-93.8%). Pain outcomes at 1 year were excellent in 58-78.4%, good or better in 77-93.75% and fair or better in 80-93.75% of patients. On average facial numbness following IN was seen in 96% of patients however at follow-up remained in only 1.75-10%. The vast majority of remaining numbness was not significantly distressing to patients. Subgroup comparisons of IN vs. recurrent MVD, IN vs. radiofrequency ablation, the impact of IN during the absence of vascular compression as well as IN with and without MVD were also evaluated. Conclusions IN represents a promising approach for surgical treatment of trigeminal neuralgia in the absence of vascular compression or in potential cases of recurrence. Complications were limited in general. Further study is required to evaluate the impact of IN via higher quality prospective studies.