Function-Preserving Multimodal Treatment for Jugular Foramen Meningiomas.

Objectives Despite being pathologically benign, jugular foramen meningioma (JFM) may be locally aggressive and spread in three compartments. Because of the complex anatomical location, radical removal of JFM usually causes serious morbidity through lower cranial nerve (LCN) deficits. To accomplish long-standing tumor control with good functional outcomes, we report function-preserving multimodal treatment (FMT) for JFM, comprising the combination of intradural tumor removal with the preservation of LCN function and stereotactic radiosurgery (RS) for the residual tumor. Materials This study investigated six JFM patients (five women, one man). Preoperatively, five patients showed no LCN sign. Results All patients underwent function-preserving retrosigmoid intradural tumor removal, and no patient developed new LCN deficit. Three patients underwent RS for the residual tumor at 8 to 12 months after surgery. After RS, all three tumors were controlled. No patients showed tumor recurrence or new LCN deficits in the follow-up period (2 months to 8 years). Conclusion FMT for JFMs can accomplish long-standing tumor control with excellent functional outcomes.

Challenging Anterior Inferior Cerebellar Artery in Retrosigmoid Vestibular Schwannoma Removal.

OBJECTIVE: Referring to the anterior inferior cerebellar artery (AICA) traversing a cerebellopontine angle tumor during retrosigmoid vestibular schwannoma (VS) removal as a challenging AICA (c-AICA), we describe incidence, anatomic characteristics, mechanism of development of c-AICA, and surgical techniques used to remove VS while preserving the AICA. METHODS: Review of surgical records and videos of 150 patients who underwent retrosigmoid VS removal revealed 10 patients (7%) with c-AICAs. Retrospective analysis of these 10 patients was performed. RESULTS: Surgical findings classified c-AICAs as c-AICAs with subarcuate artery (SAA) and c-AICAs without SAA. In c-AICAs with SAA (7/10), the SAA had an anchoring effect in the development of the c-AICA. The most challenging c-AICAs (i.e., c-AICAs reaching the porus acusticus, entering the internal auditory canal, and adhering to the dura) were associated with short cisternal SAAs (4/7). We preserved the most challenging c-AICA with the surrounding dura by drilling the posterior wall to preserve the posterior wall dura. AICAs adhering to the porus acusticus dura were not associated with long cisternal SAAs. Sacrificing the SAA caused no neurologic deficits. c-AICAs were preserved in all patients, and tumors were removed with no complications related to AICAs. CONCLUSIONS: c-AICAs occur more often than expected. The anatomy of the SAA is related to the development and characteristics of c-AICAs. Although preserving a c-AICA is challenging and necessitates a complex dissecting technique, understanding of anatomic characteristics and appropriate surgical management of c-AICAs enable VS removal while preserving the AICA.

Retrosigmoid removal of small acoustic neuroma: curative tumor removal with preservation of function.

OBJECT: Management of small acoustic neuromas (ANs) consists of 3 options: observation with imaging follow-up, radiosurgery, and/or tumor removal. The authors report the long-term outcomes and preservation of function after retrosigmoid tumor removal in 44 patients and clarify the management paradigm for small ANs. METHODS: A total of 44 consecutively enrolled patients with small ANs and preserved hearing underwent retrosigmoid tumor removal in an attempt to preserve hearing and facial function by use of intraoperative auditory monitoring of auditory brainstem responses (ABRs) and cochlear nerve compound action potentials (CNAPs). All patients were younger than 70 years of age, had a small AN (purely intracanalicular/cerebellopontine angle tumor ≤ 15 mm), and had serviceable hearing preoperatively. According to the guidelines of the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery Foundation, preoperative hearing levels of the 44 patients were as follows: Class A, 19 patients; Class B, 17; and Class C, 8. The surgical technique for curative tumor removal with preservation of hearing and facial function included sharp dissection and debulking of the tumor, reconstruction of the internal auditory canal, and wide removal of internal auditory canal dura. RESULTS: For all patients, tumors were totally removed without incidence of facial palsy, death, or other complications. Total tumor removal was confirmed by the first postoperative Gd-enhanced MRI performed 12 months after surgery. Postoperative hearing levels were Class A, 5 patients; Class B, 21; Class C, 11; and Class D, 7. Postoperatively, serviceable (Class A, B, or C) and useful (Class A or B) levels of hearing were preserved for 84% and 72% of patients, respectively. Better preoperative hearing resulted in higher rates of postoperative hearing preservation (p = 0.01); preservation rates were 95% among patients with preoperative Class A hearing, 88% among Class B, and 50% among Class C. Reliable monitoring was more frequently provided by CNAPs than by ABRs (66% vs 32%, p < 0.01), and consistently reliable auditory monitoring was significantly associated with better rates of preservation of useful hearing. Long-term follow-up by MRI with Gd administration (81 ± 43 months [range 5-181 months]; median 7 years) showed no tumor recurrence, and although the preserved hearing declined minimally over the long-term postoperative follow-up period (from 39 ± 15 dB to 45 ± 11 dB in 5.1 ± 3.1 years), 80% of useful hearing and 100% of serviceable hearing remained at the same level. CONCLUSIONS: As a result of a surgical technique that involved sharp dissection and internal auditory canal reconstruction with intraoperative auditory monitoring, retrosigmoid removal of small ANs can lead to successful curative tumor removal without long-term recurrence and with excellent functional outcome. Thus, the authors suggest that tumor removal should be the first-line management strategy for younger patients with small ANs and preserved hearing.

Involvement of human small fragment nuclease in the resistance of human cells to UV-C-induced cell death.

Human small fragment nuclease (Sfn) is one of the cellular proteins that were reported to degrade small, single-stranded DNA and RNA. However, the biological role of Sfn in cellular response to various stressors such as UV-C (mainly 254 nm wavelength ultraviolet ray) remains unclear. We have examined whether modulation of human SFN gene expression affects cell survival capacity against UV-C-induced cell death, analyzing colony survival ability in UV-C-sensitive human RSa cells treated with short double-stranded RNA (siRNA) specific for SFN messenger RNA (mRNA). The expression levels of SFN mRNA in the siRNA-treated RSa cells decreased to about 15% compared with those in the control siRNA-treated cells. The siRNA-treated RSa cells showed lower colony survival and higher activity of caspase-3 after UV-C irradiation than the control siRNA-treated RSa cells. Furthermore, the removal capacity of cyclobutane pyrimidine dimers (CPD) in the siRNA-treated RSa cells decreased compared with the control siRNA-treated RSa cells. There was no difference in the colony survival and CPD removal capacity after UV-C irradiation between the control siRNA-treated RSa cells and mock-treated RSa cells. These results suggest that SFN expression is involved in resistance of RSa cells to UV-C-induced cell death through the roles it plays in the DNA repair process.