"Letter to the editor, clinical characteristics and outcomes after trigeminal schwannoma resection: a multi-institutional experience".

The recent article "Clinical characteristics and outcomes after trigeminal schwannoma resection: a multi-institutional experience" by Nandoliya et al. offers critical insights into the management of trigeminal schwannomas (TS). This multi-institutional study, encompassing 30 patients over 18 years, highlights various surgical approaches, achieving gross-total resection in 53% of cases, and emphasizes the balance between resection and neurological preservation. The use of intraoperative neuromonitoring in 77% of cases is noted for minimizing morbidity. Despite a 13% complication rate, most were transient. Long-term follow-up data show a low recurrence rate, advocating for ongoing surveillance. The study underscores the importance of tailored surgical strategies, and the discussion of classification systems aids in contextual understanding. While the findings are robust, further research into adjuvant therapies and emerging technologies is warranted. This comprehensive overview advances our understanding of TS, promoting a patient-centered approach to surgical management.

Clinical characteristics and outcomes after trigeminal schwannoma resection: a multi-institutional experience.

Given their rarity, the clinical course of patients undergoing trigeminal schwannoma (TS) resection remains understudied. The objective of this study is to describe clinical characteristics and outcomes in patients undergoing surgical resection for TS in a multi-institutional cohort. This is a retrospective study of patients undergoing TS resection at two institutions between 2004 and 2022. Patient, radiographic, and clinical characteristics were reviewed and analyzed with standard statistical methods. Thirty patients were included. The median patient age was 43 (IQR: 35-52) years, and 14 (47%) patients were female. Median clinical and radiographic follow-ups were 43 (IQR: 20-81) and 47 (IQR: 27-97) months respectively. The most common presenting symptoms were trigeminal hypesthesia (57%) and headaches (30%), diplopia (30%), and ataxia/cerebellar signs (30%). The median maximum tumor diameter was 3.3 (IQR: 2.5-5.4) cm. Most tumors were Samii type C (50%) and mixed cystic-solid (63%). Surgical approaches included endoscopic endonasal (33%), supratentorial (30%), combined/staged (20%), infratentorial (10%), and anterior petrosal (7%) approaches. Gross-total resection was achieved in 16 (53%) patients. Radiographic tumor recurrence was noted in four patients at a median of 79 (range 5-152) months. Twenty-six (87%) patients reported improvements in at least one symptom by last follow-up. The most common perioperative complication was new cranial nerve deficit, with 17% of patients having a transient deficit and 10% having a permanent cranial nerve deficit. Surgical resection of TS showed good progression-free survival and symptom improvement, but was associated with cranial nerve deficits.

Combined open maxillectomy and endoscopic endonasal resection of a giant V2 trigeminal schwannoma.

BACKGROUND: Trigeminal schwannoma is a rare type of tumor that arises from the Schwann cells of the trigeminal nerve. METHOD: We present a case of a patient with a giant V2 trigeminal schwannoma with painful swelling in the left maxilla. A complete resection using a combined open maxillectomy and endoscopic endonasal approach was performed. CONCLUSION: This case highlights the importance of a multidisciplinary approach to perform a combined open and endoscopic approach for safe resection while preserving adequate speech and swallowing.

Multiple Intracranial Schwannomas of the Vestibular and Trigeminal Nerves: A Technical Note.

BACKGROUND: A schwannoma is a nerve sheath tumor that is formed by Schwann cells. Vestibular schwannomas are thought to account for the majority of intracranial schwannomas. Nonvestibular schwannomas account for about 10%, about half of which are trigeminal schwannomas. Multiple intracranial schwannomas originating from different cranial nerves are extremely rare. METHODS: We describe the clinical case of a 42-year-old female patient with vestibular schwannoma and multiple trigeminal schwannomas. RESULTS: That case shows how multiple trigeminal schwannomas were identified intraoperatively during elective surgery for vestibular schwannoma removal, most of which were resected. No new neurological deficits were observed in the patient. CONCLUSIONS: The presence of multiple intracranial schwannomas is extremely rare in neurosurgical practice and can change the intraoperative strategy and the course of the surgery.

Innovative surgical approach for trigeminal trophic syndrome: Successful healing of facial ulcers through cross-face nerve grafts.

BACKGROUND: Trigeminal trophic syndrome (TTS) is a rare condition caused by damage to the trigeminal nervous system, resulting in sensory disturbances and ulcers on the face. Treating TTS is complex and often requires medical or surgical intervention like flap reconstruction. However, there is limited research on surgical treatments for TTS ulcers. METHODS: We report the case of a 19-year-old man with TTS. We employed an innovative surgical technique involving dual cross-face nerve grafts. In the initial procedure, corneal neuralization was accomplished using supraorbital and cross-face infraorbital nerve graft. The subsequent operation utilized auricular composite tissue flap transplantation repair and cross-face mental nerve graft. RESULTS: This procedure led to rapid and sustained healing, as well as aesthetic improvement. CONCLUSION: Cross-face nerve grafts is a promising tool in the treatment of refractory ulcers caused by diseases such as TTS.

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.

Long-Term Outcome of Unilateral Acoustic Neuromas With or Without Hearing Loss: Over 10 Years and Beyond After Gamma Knife Radiosurgery.

BACKGROUND: Since the long-term outcomes of 162 patients who underwent gamma knife radiosurgery (GKS) as an initial or adjuvant treatment for acoustic neuromas (ANs) with unilateral hearing loss were first reported in 1998, there has been no report of a comprehensive analysis of what has changed in GKS practice. METHODS: We performed a retrospective study of the long-term outcomes of 106 patients with unilateral sporadic ANs who underwent GKS as an initial treatment. The mean patient age was 50 years, and the mean initial tumor volume was 3.68 cm3 (range, 0.10-23.30 cm3). The median marginal tumor dose was 12.5 Gy (range, 8.0-15.0 Gy) and the median follow-up duration was 153 months (range, 120-216 months). RESULTS: The tumor volume increased in 11 patients (10.4%), remained stationary in 27 (25.5%), and decreased in 68 patients (64.2%). The actuarial 3, 5, 10, and 15-year tumor control rates were 95.3 ± 2.1%, 94.3 ± 2.2%, 87.7 ± 3.2%, and 86.6 ± 3.3%, respectively. The 10-year actuarial tumor control rate was significantly lower in the patients with tumor volumes of ≥ 8 cm3 (P = 0.010). The rate of maintaining the same Gardner-Robertson scale grade was 28.6%, and that of serviceable hearing was 46.4%. The rates of newly developed facial and trigeminal neuropathy were 2.8% and 4.7%, respectively. The patients who received marginal doses of less than 12 Gy revealed higher tumor control failure rates (P = 0.129) and newly occurred facial or trigeminal neuropathy rates (P = 0.040 and 0.313, respectively). CONCLUSION: GKS as an initial treatment for ANs could be helpful in terms of tumor control, the preservation of serviceable hearing, and the prevention of cranial neuropathy. It is recommended to perform GKS as soon as possible not only for tumor control in unilateral ANs with hearing loss but also for hearing preservation in those without hearing loss.

Postoperative trigeminal neuropathy outcomes following surgery for tumors involving the trigeminal nerve.

OBJECTIVE: To observe the evolution and outcomes of postoperative trigeminal neuropathy following surgery of tumor involving the trigeminal nerve. METHODS: A prospective observational study was conducted between October 2018 and February 2019 involving 25 patients with tumors confirmed to involve the trigeminal nerve during surgery by senior author. Pre- and postoperative trigeminal nerve function status and clinical data were recorded. RESULTS: This study included 18 cases of meningioma and seven of trigeminal schwannoma. Among the meningioma cases, 55.6% of the patients reported facial sensory dysfunction before surgery, 33.3% presented ocular discomfort, and 5.6% had masticatory muscle atrophy. Postoperatively, all patients experienced facial paresthesia, 94.4% complained of eye dryness, and one (5.56%) exhibited keratitis. Additionally, one patient (5.56%) showed new-onset masticatory weakness. During follow-up, 50.0% of patients reported improvement in facial paresthesia, and one (5.56%) experienced deterioration. Eye dryness resolved in 35.3% of patients, and keratitis remission was observed in one patient. However, one patient (5.56%) developed neurotrophic keratitis. Overall, 55.6% of patients displayed mild masticatory weakness without muscle atrophy. In the cases of schwannoma, 28.6% of patients had facial paresthesia before surgery, 42.9% showed ocular discomfort, and one (14.3%) complained of masticatory dysfunction. Postoperatively, 85.7% of patients reported facial paresthesia and eye dryness, with one patient (16.7%) experiencing keratitis. During follow-up, 66.7% of patients demonstrated improvement in facial paresthesia, 28.6% showed eye dryness remission, and one patient (16.7%) recovered from keratitis. However, one patient (16.7%) developed new-onset neurotrophic keratitis. One patient (16.7%) experienced relief of masticatory dysfunction, but 42.9% reported mild deterioration. Another patient (14.3%) had facial anesthesia that had not improved. CONCLUSION: Postoperative trigeminal neuropathy is a common complication with a high incidence rate and poor recovery outcomes after surgery for tumors involving the trigeminal nerve. When trigeminal nerve damage is unavoidable, it is essential to provide a multidisciplinary and careful follow-up, along with active management strategy, to mitigate the more severe effects of postoperative trigeminal neuropathy.

Semiscleral Contact Lens Use After Direct Corneal Neurotization for Neurotrophic Keratopathy.

PURPOSE: To describe a case of a patient treated for neurotrophic keratopathy (NK) with direct corneal neurotization (CN), where a modification to the CN technique allowed for semiscleral contact lens use postoperatively. OBSERVATION: Our patient had successful CN with improved corneal sensation. During the procedure, a 1.0 mm gutter was created between the limbus and nerve graft to allow for semiscleral contact lens fitting. CONCLUSIONS: With the use of preoperative planning and a limbal gutter during CN, a semiscleral contact lens can serve as a well-tolerated postoperative management option to improve visual acuity and protect the corneal surface in patients with NK.

Bilateral Corneal Neurotization for Ramos-Arroyo Syndrome and Developmental Neurotrophic Keratopathy: Case Report and Literature Review.

PURPOSE: The purpose of this study was to report the use of bilateral corneal neurotization for neurotrophic keratitis in the setting of Ramos-Arroyo syndrome. METHODS: The case report and surgical technique are described in detail in this article, as well as a review of the literature on corneal neurotization for congenital corneal anesthesia. RESULTS: We report a 17-year-old patient who underwent bilateral corneal neurotization for neurotrophic keratitis secondary to corneal anesthesia in Ramos-Arroyo syndrome. Corneal neurotization was performed with great auricular nerve transfers extended by sural nerve autografts. CONCLUSIONS: We present the treatment of neurotrophic keratopathy with corneal neurotization in a patient with Ramos-Arroyo syndrome. We describe how bilateral corneal neurotization using the great auricular nerve technique is a safe and effective procedure for patients with congenital/developmental corneal anesthesia.

Corneal neurotization in the management of neurotrophic keratopathy: A review of the literature.

Neurotrophic keratopathy (NK) is a rare degenerative disease in which damage to the corneal nerves leads to corneal hypoesthesia or anesthesia. Neurotrophic corneal ulcers are notoriously difficult to treat and can lead to blindness. Corneal neurotization (CN) is a recent surgical technique aimed at restoring corneal sensation and may offer a definitive treatment in the wake of NK. Herein, we review the surgical techniques utilized in direct and indirect CN. Technical considerations, outcomes, current limitations and future perspectives are also discussed. This article highlights the key points of this promising procedure and biological aspects that will help provide the best treatment options for patients with severe NK.

Two-Stage Resection of a Giant Trigeminal Schwannoma in a Non-Neurofibromatosis Type 2 Pediatric Patient: A Case Report, Systematic Review, and Intraoperative Video.

BACKGROUND: Trigeminal schwannoma is an uncommon tumor in pediatric patients. Several surgical approaches have been described in the literature. METHODS: The case of an 11-year-old boy with a giant dumbbell-shaped trigeminal schwannoma removed through a 2-stage approach was presented with an intraoperative video. Using PubMed and Scopus, the literature on trigeminal schwannoma in pediatric patients was searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. RESULTS: The search strategy yielded 312 titles, of which 13 were included in the review. Cases of trigeminal schwannoma were described, with a highly variable clinical presentation and anatomical arrangement in cranial fossae. Two-stage approaches were reported, although most studies described single-stage approaches. Common postoperative outcomes were a range of disturbances of cranial nerve V. CONCLUSIONS: The surgical approach varies based on the tumor conformation. However, a 2-stage pterional subtemporal and semisitting retrosigmoid approach is a safe, practical, and effective strategy for the removal of dumbbell-shaped trigeminal schwannoma in a pediatric patient.

Sustained Release of Tacrolimus From a Topical Drug Delivery System Promotes Corneal Reinnervation.

Purpose: Corneal nerve fibers provide sensation and maintain the epithelial renewal process. Insufficient corneal innervation can cause neurotrophic keratopathy. Here, topically delivered tacrolimus is evaluated for its therapeutic potential to promote corneal reinnervation in rats. Methods: A compartmentalized neuronal cell culture was used to determine the effect of locally delivered tacrolimus on sensory axon regeneration in vitro. The regenerating axons but not the cell bodies were exposed to tacrolimus (50 ng/mL), nerve growth factor (50 ng/mL), or a vehicle control. Axon area and length were measured after 48 hours. Then, a biodegradable nanofiber drug delivery system was fabricated via electrospinning of a tacrolimus-loaded polycarbonate-urethane polymer. Biocompatibility, degradation, drug biodistribution, and therapeutic effectiveness were tested in a rat model of neurotrophic keratopathy induced by stereotactic trigeminal nerve ablation. Results: Sensory neurons whose axons were exposed to tacrolimus regenerated significantly more and longer axons compared to vehicle-treated cultures. Trigeminal nerve ablation in rats reliably induced corneal denervation. Four weeks after denervation, rats that had received tacrolimus topically showed similar limbal innervation but a significantly higher nerve fiber density in the center of the cornea compared to the non-treated control. Topically applied tacrolimus was detectable in the ipsilateral vitreal body, the plasma, and the ipsilateral trigeminal ganglion but not in their contralateral counterparts and vital organs after 4 weeks of topical release. Conclusions: Locally delivered tacrolimus promotes axonal regeneration in vitro and corneal reinnervation in vivo with minimal systemic drug exposure. Translational Relevance: Topically applied tacrolimus may provide a readily translatable approach to promote corneal reinnervation.

Thirty-year clinical experience in gamma knife radiosurgery for trigeminal schwannomas.

We aimed to evaluate the radiographic and clinical outcomes after gamma knife radiosurgery (GKRS) for trigeminal schwannomas (TSs). A total of 87 patients who underwent GKRS for TSs between 1990 and 2020 were enrolled. The mean tumor volume was 4.3 cm3. The median prescribed dose for the margins of the tumor was 13 Gy. The median follow-up duration was 64.3 months (range 12.0-311.5 months). The overall local tumor control rate was 90%, and the symptom response rate was 93%. The response rate for each symptom was 88% for facial pain, 97% for facial sensory change, and 86% for cranial nerve deficits. Nineteen (22%) patients showed transient swelling, which had regressed at the time of the last follow-up. Cystic tumors were associated with transient swelling (p = 0.04). A tumor volume of < 2.7 cm3 was associated with local tumor control in univariable analysis. Transient swelling was associated with symptom control failure in both univariable and multivariable analyses (p = 0.04, odds ratio 14.538). GKRS is an effective treatment for TSs, both for local control and symptom control.

Pediatric benign triton tumor of trigeminal nerve: a case report and literature review.

PURPOSE: Benign triton tumors (BTTs) in the pediatric population are extremely rare occurrences. Paucity of data on BTTs poses both diagnostic and therapeutic challenges, particularly when found intracranially. METHODS: A case report of a 10-year-old male diagnosed with incidental maxillary trigeminal (V2) BTT is presented. We discuss radiographic and histopathological interpretations. Furthermore, we provide a brief review of current literature and historical background on pediatric trigeminal BTT diagnosis, histopathology, and management. RESULTS: Successful gross total resection of the tumor was achieved via Dolenc approach to the cavernous sinus. Management options with consideration of outcomes from the few prior cases reported in the literature are presented. CONCLUSION: Treatment of trigeminal nerve tumors requires a broad differential diagnosis and understanding rare tumors is essential in the diagnosis and treatment algorithm.

[Treatment of neurotrophic keratopathy in combined lesions of the trigeminal and facial nerves]. / Lechenie neirotroficheskoi keratopatii pri sochetannom porazhenii troinichnogo i litsevogo nervov.

Ocular symptomatology in lesions of the facial nerve is associated with disturbed innervation of the circular muscle of the eye that leads to disruption of the protective function of the eyelids and the development of exposure symptoms, and is accompanied by a breach in corneal tear film integrity. The main clinical manifestation of the trigeminal nerve damage is the loss of sensory innervation of the cornea and disruption of the supply of neurotransmitters to its cells, manifesting as corneal hypo- or anesthesia. This triggers a cascade of pathological processes that lead to the development of neurotrophic keratopathy. In combined pathology of the facial and trigeminal nerves, a number of interrelated and mutually aggravating problems arise that require correction of lagophthalmos and functional restoration of the trigeminal nerve, since there is an interaction between the corneal epithelium and trigeminal neurons through trophic neuromodulators, which normally contribute to the proliferation of epithelial cells, their differentiation, migration and adhesion, and are essential for vital functions, metabolism and healing of surface lesions of the eye. Classical methods of treating neurotrophic keratopathy aim to protect the ocular surface, and are palliative or auxiliary, do not provide radical relief of the symptoms of neurotrophic keratopathy. Modern surgical technique of neurotization of the cornea allows restoring the structural growth of the nerve, which provides nerve trophism and corneal sensitivity, and is the only pathogenetically substantiated method of effective treatment of neurotrophic keratopathy. At the same time, direct neurotization has undeniable advantages over methods involving intercalary donor nerves, since neuropeptides from nerve fibers are immediately released into the recipient tissue and start reparative processes. Taking into account the accumulated positive experience of neurotization surgeries, scientific and clinical research should be continued in order to improve the most effective methods of corneal neurotization and promote their wider implementation into clinical practice.

Neurotrophic keratopathy: current challenges and future prospects.

Neurotrophic keratopathy (NK), or neurotrophic keratitis, is a degenerative condition that results from decreased innervation to the cornea. The cornea is innervated by the ophthalmic branch of the trigeminal nerve. Neurotrophic keratopathy is most commonly caused by herpes keratitis however, any condition that disrupts the normal corneal innervation can cause NK. Neurotrophic keratopathy is a clinical diagnosis and is classified into three stages based on the disease severity. Stage 1 has mild epithelial defects, such as punctate keratopathy, stage 2 disease has persistent epithelial defects, and stage 3 is defined by the presence of ulcers. Current treatment modalities consist of medical and surgical options. Stage 1 is treated with lubrication through artificial tears, eyelid taping, and punctal plug/cautery. Stage 2 treatment can involve therapeutic contact lenses, topical autologous or allogenic serum, tarsorrhaphy, botulinum toxin injections, and possibly anti-inflammatory medications. Stage 3 disease may require human nerve growth factor, amniotic membrane transplantation, conjunctival flap, or corneal neurotization. New therapies, such as matrix regenerating therapy, plasma rich in growth factors, Thymosin ß4, Substance P/Insulin like growth factor-1, and nicergoline represent exciting future options.KEY MESSAGESNeurotrophic keratopathy is a rare degenerative disease defined by decreased innervation to the cornea that is associated with significant morbidity.Treatment options range from lubrication alone to various medical and surgical treatments.Matrix regenerating therapy, plasma rich in growth factors, Thymosin ß4, Substance P/Insulin like growth factor-1, and nicergoline are exciting novel therapies that will influence how neurotrophic keratopathy is treated in the future.