Predictors of Surgical Outcomes in Patients with Abducens Nerve Schwannoma: A Comprehensive Systematic Review and a Case Report.

BACKGROUND: Abducens nerve (AN) schwannomas are extremely rare tumors. Clinical characteristics and factors that influence postoperative outcomes are not well defined. OBJECTIVE: To characterize clinical features of AN schwannomas and predictors of surgical outcomes. METHODS: PRISMA-guided systematic review of the literature on AN schwannomas was performed. Subsequently, univariate and multivariate regression analyses were performed to identify the predictive value of variables that influence postoperative outcomes. RESULTS: A total of 42 studies with 55 patients were evaluated. The mean age at presentation was 43.9 ± 14.6 years. The most common presenting symptom was cranial nerve VI palsy (69.1%). Cavernous sinus (49.1%) and prepontine cistern (36.3%) were the most commonly involved locations. Complete recovery after surgery was seen in 36.3% at a median follow-up of 28.4 ± 25.8 months. Preoperative AN palsy (P < 0.001), suboccipital approach (P = 0.007), and subtotal resection of tumor (P = 0.044) were significant protective factors for postoperative complications. Prepontine location and postoperative complications were poor prognostic indicators of AN recovery (odds ratio [OR], 0.10, P = 0.030 and OR, 0.10, P = 0.028, respectively). Subtotal resection was significantly correlated with higher odds of AN recovery (OR, 6.06; P = 0.040). CONCLUSIONS: AN schwannomas are rare but serious tumors that can cause significant morbidity, with only approximately one third of patients showing complete recovery after surgery. The suboccipital approach was a protective factor for postoperative complications, especially when combined with subtotal resection. Knowledge of these factors along with tumor characteristics helps optimize surgical planning and preoperative counseling.

Symptomatic perineural and intraneural invasion of the trigeminal nerve and subsequent abducens Nerve palsy by cutaneous squamous cell carcinoma.

A 74-year-old woman who presented initially with trigeminal neuralgia of the left forehead and scalp was later found to have a poorly differentiated squamous cell carcinoma (SCC) with large-nerve perineural and intraneural invasion of the left supraorbital nerve. Negative histopathologic margins were achieved in three stages of permanent fixed tissue en face processing and the final defect was repaired with a large rotation flap. Approximately one month after repair, the patient presented with new-onset diplopia and was found to have a complete left cranial nerve VI palsy suspicious for continued disease spread. MRI confirmed perineural spread along the ophthalmic branch of the trigeminal nerve through the superior orbital fissure into the cavernous sinus. She was subsequently treated with radiation therapy (66Gy in 33 fractions). The involvement of two distinct cranial nerves by perineural invasion is uncommon and has mostly been described involving branches of the trigeminal and facial nerves. This case highlights the rare presentation of perineural invasion involving both the trigeminal nerve and the abducens nerve. Anatomically, this clinical presentation can be explained by the retrograde perineural spread along the ophthalmic branch of the trigeminal nerve through the supraorbital fossa into the cavernous sinus where these two nerves are in close proximity.

Sphenoid sinus cholesterol granulomas presenting with abducens nerve palsy.

We discuss two patients who presented with sphenoid sinus cholesterol granulomas and associated unilateral abducens nerve palsies. Two case reports from our institution are reported. A literature review of available articles is presented, discussing both cholesterol granulomas of the sphenoid sinus and sphenoid sinus lesions that present with unilateral abducens palsy. A total of nine cases of sphenoid sinus cholesterol granulomas have been previously reported in the literature. A wide variety of sphenoid sinus pathologies can present with unilateral abducens nerve palsies, however no sphenoid sinus cholesterol granulomas with this presentation were found in the literature. In conclusion, cholesterol granulomas should be included in the differential when a patient presents with an expansile mass of the sphenoid sinus and associated unilateral abducens nerve palsy.

Abscess of the cavernous sinus in a child: a case report.

BACKGROUND: The cavernous sinus, which has several important structures, can be affected by various lesions, including tumor, vascular, infection, and inflammation. CASE REPORT: We reported a rare case of abscess of the cavernous sinus in a child presenting with headache and abducens paralysis. Exploratory surgery was performed via the Dolenc approach, and the patient recovered from abducens paralysis 3 months later. CONCLUSION: Abscess of the cavernous sinus is rare.  Inspection of cavernous sinus can confirm the characteristics of the lesion and decompress the cavernous sinus, which may be beneficial for nerve function recovery.

Metastatic Lesions of the Clivus: A Systematic Review.

BACKGROUND: Metastatic lesions of the clivus are extremely rare, having previously been estimated as representing 0.02% of all intracranial tumors. Owing to its close intracranial relationship with the clivus before entering the cavernous sinus, clinical palsies of the sixth cranial nerve have been classically associated with destructive lesions of this structure. METHODS: A comprehensive search of PubMed was conducted for studies of patients with metastasis to the clivus from primary cancer at any site. Studies reported in English in the past 20 years from our last search on April 12, 2021 were included. The data collected included patient age, sex, symptoms at presentation, histopathology and treatment timeline of the primary tumor, treatment, follow-up, and mortality. RESULTS: After the literature review, 46 studies reporting on 58 patients with clivus metastasis were included in the final analysis. The mean age of the patients was 57.5 years, and 39 were male (67.2%). The most common sites of the primary tumor were the prostate (22%), gastrointestinal tract (15%), lung (13%), and kidney (11%). In 43% of patients, symptoms of clivus metastasis had presented before the diagnosis of primary cancer was known, and 71% of the patients had presented with sixth nerve palsy. Of the 58 patients, 53% had undergone surgery, and 37% had received adjuvant radiotherapy. Of the 58 patients, 25% had received radiotherapy alone. The endoscopic transsphenoidal approach to the clivus was almost uniquely used for surgical management. Survival data were available for 31 patients. Death had occurred at a mean of 9.4 months after the presentation of clivus metastasis. A strong correlation was found between the interval from primary cancer to the presentation of clivus metastasis and mortality. CONCLUSIONS: Although an extremely rare occurrence, clivus metastasis should be considered in patients with a history of malignancy, in particular, prostate malignancy, presenting with new-onset isolated sixth nerve palsy.

Compartmental Strabismus.

Recent reports confirm innervational compartments of select rectus extraocular muscles as well as the superior oblique.1 Histopathological and orbital imaging studies demonstrate well defined compartmental innervation of the horizontal rectus muscles with less differentiation in the vertical rectus muscles. Acquired vertical misalignment not associated with cyclovertical muscle dysfunction has been associated with horizontal rectus muscle compartment dysfunction. Pattern and other forms of strabismus have been associated with segmental or compartmental abnormal innervation of the extraocular muscles. Taking advantage of segmental function and innervation, selective weakening and strengthening procedures have been used to treat patients with incomitant near/distance disparities, incomitant vertical and torsional strabismus, and patients with A- and V-pattern strabismus.

Petrous apex non-secretory plasma cell myeloma with aberrant cytokeratin expression.

Multiple myeloma is a monoclonal proliferation of plasma cells with common involvement of vertebrae, ribs and skull vault. However, involvement of skull base is relatively uncommon and myeloma manifesting initially as a petrous apex mass is distinctly rare. We report a rare case of non-secretory multiple myeloma in a 52-year-old Egyptian male presenting primarily as a right petrous apex mass with abducens nerve palsy. Additionally, neoplastic cells aberrantly expressed cytokeratin. Although rare, plasma cell myeloma should be considered in the differential diagnosis of petrous apex masses.

Unilateral Lateral Rectus Paralysis Showing Incomplete "V" Sign' on 18F-FDG PET/CT.

Extraocular muscles show physiologic radiotracer uptake on F-FDG PET/CT as is encountered in most routine scans. Certain pathologies can cause palsy of one or more of the extraocular muscles, leading to hypometabolism on F-FDG PET/CT. We present a case with a classical finding of unilateral hypometabolism of the lateral rectus muscle, disrupting the "V" sign formed due to physiologic uptake. The patient had presented with the complaint of diplopia and was being evaluated further to rule out the possibility of inflammatory/granulomatous infectious etiopathogenesis leading to compression of the abducens nerve resulting in lateral rectus palsy.

The incidence and etiology of sixth cranial nerve palsy in Koreans: A 10-year nationwide cohort study.

We aimed to investigate the incidence, prevalence, and etiology of sixth cranial nerve (CN6) palsy in the general Korean population. The nationally representative dataset of the Korea National Health Insurance Service-National Sample Cohort from 2006 through 2015 was analyzed. The incidence and prevalence of CN6 palsy were estimated in the cohort population, confirming that incident cases of CN6 palsy involved a preceding disease-free period of ≥4 years. The etiologies of CN6 palsy were presumed using comorbidity conditions. Among the 1,108,256 cohort subjects, CN6 palsy developed in 486 patients during the 10-year follow-up. The overall incidence of CN6 palsy was estimated to be 4.66 per 100,000 person-years (95% confidence interval [CI], 4.26-5.08) in the general population. This incidence increased with age, accelerating after 60 years of age and peaking at 70-74 years of age. The mean male-to-female incidence ratio was estimated as 1.41 in the whole population, and the incidence and prevalence of CN6 palsy showed an increasing trend over time in the study period. Surgical incidence for CN6 palsy was only 0.19 per 100,000 person-years (95% CI, 0.12-0.29). The etiologies were presumed to be vascular (56.6%), idiopathic (27.2%), neoplastic (5.6%), and traumatic (4.9%). In conclusion, the incidence of CN6 palsy increases with age, peaking at around 70 years, and shows a mild male predominance in Koreans.

Vertical rectus transposition procedures for lateral rectus palsy: A systematic review.

Multiple transposition procedures have been described for management of lateral rectus palsy. However, relative effect and indications of each procedure are unclear. This systematic review was planned to evaluate functional and anatomical outcomes of vertical rectus transposition (VRT) surgery in patients with lateral rectus palsy. We searched databases in English language, namely, MEDLINE, PubMed Central, EMBASE, Google Scholar, Scopus, and Index Copernicus without any date restrictions in electronic searches, using the search words 'vertical rectus transposition for lateral rectus palsy," "vertical rectus transposition for abducens palsy," "superior rectus transposition," "inferior rectus transposition," and "Hummelsheim procedure." References of the selected publications were also searched to find any relevant studies. We searched for studies that provided data on single VRT and double VRT surgeries for lateral rectus palsies. Three authors independently assessed the related studies gathered from electronic and manual searches. We found 27 studies which were relevant to the review question. As there were no randomized control trials (RCTs) available related to our study question, nonrandomized studies were used to arrive at summarization of outcomes of different transposition procedures. There is a need for prospective RCTs to investigate the different types of transposition procedures for lateral rectus palsy.

Procedimiento de Nishida asociado a toxina botulínica en parálisis completa del sexto par craneal bilateral de larga evolución / Nishida procedure associated with botulinum toxin in a long-standing complete bilateral sixth cranial nerve palsy

En los casos graves de parálisis del abducens o sexto par craneal resultan útiles las transposiciones de rectos superiores y rectos inferiores hacia el recto lateral paralítico. Se han descrito numerosas técnicas a lo largo del tiempo para la realización de estas transposiciones, como son las de Hummelsheim, O’Connor, Jensen, Foster o Nishida. Las 4 primeras llevan aparejado un aumento del riesgo de isquemia del segmento anterior. Presentamos el caso de una parálisis de sexto par craneal bilateral de larga data de evolución, secundaria a un traumatismo craneoencefálico grave. Para minimizar el riesgo de isquemia del segmento anterior se optó por la realización de la técnica de Nishida, asociada a inyección de toxina botulínica en ambos rectos medios para tratar de resolver la contractura muscular asociada a la larga evolución del caso, obteniendo buenos resultados a los 6 y 12 meses del procedimiento quirúrgico

In severe cases of abducens or sixth cranial nerve palsy, transpositions of the superior rectus and inferior rectus into the paralytic lateral rectus have been demonstrated to be useful. Numerous techniques have been described over time to carry out these transpositions, such as the Hummelsheim, O’Connor, Jensen, Foster, or Nishida technique. The first 4 techniques mentioned above have an increased risk of anterior segment ischaemia. The case is presented of a long-standing bilateral sixth cranial nerve palsy secondary to a severe cranial injury. Given the risk of ischaemia of the anterior segment, the Nishida technique was chosen in order to reduce the risk of suffering from this complication. This is combined with botulinum toxin in both middle rectus to try to resolve the muscle contracture associated with the long evolution of the case, obtaining good results at 6, and 12 months after the surgical procedure

Nishida procedure associated with botulinum toxin in a long-standing complete bilateral sixth cranial nerve palsy. / Procedimiento de Nishida asociado a toxina botulínica en parálisis completa del sexto par craneal bilateral de larga evolución.

In severe cases of abducens or sixth cranial nerve palsy, transpositions of the superior rectus and inferior rectus into the paralytic lateral rectus have been demonstrated to be useful. Numerous techniques have been described over time to carry out these transpositions, such as the Hummelsheim, O'Connor, Jensen, Foster, or Nishida technique. The first 4 techniques mentioned above have an increased risk of anterior segment ischaemia. The case is presented of a long-standing bilateral sixth cranial nerve palsy secondary to a severe cranial injury. Given the risk of ischaemia of the anterior segment, the Nishida technique was chosen in order to reduce the risk of suffering from this complication. This is combined with botulinum toxin in both middle rectus to try to resolve the muscle contracture associated with the long evolution of the case, obtaining good results at 6, and 12 months after the surgical procedure.

Diplopia: a unique presentation of recurrence of a salivary gland carcinoma.

A 79-year-old man with a history of radical excision of a left submandibular gland carcinoma ex-pleomorphic adenoma presented with a new 2 cm lump in his left submandibular region which proved to be recurrence on surgical excision. During work up for revision surgery he developed a right VI cranial nerve palsy, which was attributed to his microvascular status having had a history of three previous transient ischemic attacks (TIAs). 6 months later, his palsy had not resolved. MRI revealed new soft tissue by the cavernous segment of the internal carotid artery. The exact source of this was unclear as there was no evidence of local recurrence or nodal disease. A repeat MRI scan 16 months later revealed further growth of abnormal tissue in the cavernous sinus and the primary submandibular location, now involving multiple nerves including branches of cranial nerves IV, V, VI, VII and XII making surgical excision impossible.

Isolated Oculomotor and Abducens Nerve Palsies as Initial Presentation of Cavernous Sinus Tuberculoma: Case Report and Literature Review.

BACKGROUND: Central nervous system tuberculoma is the most severe manifestation of extrapulmonary tuberculosis with high mortality. Cavernous sinus tuberculoma (CST) is a very rare central nervous system tuberculoma with few cases reported in the literature. CASE DESCRIPTION: A 57-year-old woman was admitted to our clinic with acute diplopia and headache limited to the right side. There was no specific medical history except for migraine, depression, and anxiety, all of which were controlled by oral medications. Physical examination revealed ptosis and mydriasis in the right eye, which indicated right third and sixth cranial nerve palsies. Pituitary magnetic resonance imaging showed a right parasellar lesion at the cavernous sinus wall and ophthalmic nerve. Laboratory examinations and brain computed tomography scan showed negative findings. Initial differential diagnosis included meningioma, sarcoidosis, tuberculoma, and lymphoma. However, results of further studies, including blood and cerebrospinal fluid cultures and Mycobacterium tuberculosis DNA assay, were negative. Biopsy of the cerebral lesion was performed through the subfrontal approach, and histopathologic study confirmed CST. She was treated with a standard antituberculous regimen. After 12 months of follow-up, no cerebral or clinical findings were seen. CONCLUSIONS: CST is a rare presentation of M. tuberculosis, and the diagnosis is a difficult challenge. However, accurate diagnosis and timely treatment of CST can result in complete cure.

Bilateral abducens nerve palsies and urinary retention caused by the rupture of a vertebral artery aneurysm: A case report and literature review.

RATIONALE: Bilateral abducens nerve deficits caused by vertebral artery (VA) aneurysm have been reported, but there have been no reports regarding accompanying urinary retention. PATIENT CONCERNS: In this report, we describe an unusual case with bilateral abducens nerve palsy and urinary retention due to rupture of a vertebral aneurysm. DIAGNOSES: Subarachnoid hemorrhage caused by the rupture of a left VA aneurysm. INTERVENTIONS: The VA aneurysm was successfully controlled by coil embolization. OUTCOMES: Urinary retention was improved after embolization and recovered by the day the patient left hospital. The bilateral abducens nerve palsy gradually recovered 6 months later. LESSONS: This case emphasizes the importance of maintaining a broad, open mind in approaching the diagnosis and management of urinary retention associated with cranial nerve symptoms and reacting quickly to the clinical developments.

Midbrain Infarction Resulting in Bilateral Pseudoabducens Palsies.

INTRODUCTION: Pseudoabducens palsy refers to abduction paresis in the absence of a pontine or peripheral nerve process. This finding has been described with mesodiencephalic lesions, and likely has a common mechanism with thalamic esotropia. CASE REPORT: We describe the case of a 55-year-old man who presented with near-complete ophthalmoparesis, sparing only adduction of the left eye. Magnetic resonance imaging of the brain demonstrated midbrain infarction. CONCLUSIONS: Pseudoabducens palsy is likely underrecognized, but can be highly localizing when identified. Possible pathophysiologic mechanisms for this finding are discussed.

Abducens nerve palsy due to inferior petrosal sinus thrombosis.

Isolated unilateral abducens nerve palsy is usually due to ischemia, trauma or neoplasm. Dorello's canal is the space between the petrous apex and superolateral portion of the clivus, bound superiorly by Gruber's ligament. The abducens nerve travels with inferior petrosal sinus (IPS) though the Dorello's canal before entering the cavernous sinus. A 31-year-old man presented with neck pain, and binocular horizontal diplopia, worse looking towards left and at distance. He had a history of intravenous drug abuse but no history of hypertension or diabetes. On examination, he had complete left 6th nerve palsy with normal fundi, pupils, and other cranial nerves. Methicillin-resistant Staphylococcus aureus bacteremia was detected with naïve tricuspid valve endocarditis and multiple septic emboli to lungs with infarcts. His cerebrospinal fluid was normal. MRI of the brain was normal. MRV of head and neck showed thrombosis of the left internal jugular vein, left sigmoid sinus and left inferior petrosal sinus with normal cavernous sinus and no evidence of mastoiditis. He was treated with broad spectrum antibiotics. He was not anticoagulated for fear of pulmonary hemorrhage from pulmonary infarcts. Although cerebral venous sinus thrombosis commonly presents with elevated intracranial pressure, isolated ipsilateral 6th nerve palsy from its compression in Dorello's canal due to thrombosis of the ipsilateral inferior petrosal sinus is extremely rare. To our knowledge, only two patients have been reported with isolated abducens palsy due to IPS thrombosis; one caused by septic emboli and the other developed it during IPS cortisol level sampling.

Cavernous sinus syndrome: A prospective study of 73 cases at a tertiary care centre in Northern India.

OBJECTIVES: To study the clinical and etiological profile of patients with cavernous sinus syndrome (CSS) and identify factors which could determine the etiology and influence the outcome of these patients. PATIENTS AND METHODS: This prospective observational study included 73 consecutive patients satisfying the criteria of CSS (i.e. involvement of any 2 of the 3rd, 4th, 5th and 6th cranial nerves or any one of them with radiological evidence of cavernous sinus involvement). All these patients were subjected to detailed haematological, biochemical and radiological investigations and diagnosed and treated as per guidelines. The clinical and investigational data was recorded and analysed meticulously. RESULTS: A definitive etiological diagnosis of CSS could be achieved in 86% of patients. Tumours, fungal infections and Tolosa Hunt syndrome (THS) were most common causes. On univariate analysis, diabetes, severe vision loss (visual acuity of <3/60 in at least one eye), and presence of nasal discharge showed a significantly positive association with a fungal CSS. Evidence of paranasal sinusitis, bone erosion and ICA (internal carotid artery) involvement on Gadolinium enhanced MRI (magnetic resonance imaging) of brain were significantly associated with a fungal CSS (p=0.0001), whereas involvement of orbital apex had a negative association with a neoplastic etiology (p=0.014). On multiple logistic regression, orbital apex involvement on MRI was associated with diagnosis of THS (p=0.019, OR: 18.7; 95% CI: 1.6-217.4) while MRI evidence of paranasal sinusitis (p=0.014, OR: 45; 95% CI: 2.1-94.3) and bone erosion ((p=0.019, OR: 12.5; 95% CI: 1.5-103) correlated with diagnosis of fungal CSS. 65.2% of patients (fungal CSS- 70%) had a good prognosis at six months follow up. CONCLUSION: Most patients with CSS can be diagnosed accurately and managed properly with good outcomes.