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Background: In 10-15% of cases of vestibular schwannoma (VS) age at diagnosis is 40 years or less. Little is known about the differences in natural history, surgical findings and postoperative outcomes of such younger patients as compared to those of greater age. Objectives : To analyze clinical and surgical and imaging data of a consecutive series of n=50 patients with unilateral sporadic VS, aged 40 years or younger – separated in a very young group (15-30 years) and a moderately young group (31-40 years). Study design: Retrospective case series Methods: 50 consecutive patients under 40 years of age underwent microsurgical resection of unilateral sporadic VS via the retrosigmoid approach. The study cohort was subdivided into two groups according to the age range: Group A, age range 15-30 years (n=23 patients) and Group B, age range 31-40 years (n=27 patients). The adherence of VS capsule to surrounding nervous structures and the tendency of the tumors to bleed were evaluated by reviewing video records; the course of the FN in relation to the tumor’s surface was assessed in each case. Microsurgical removal of tumor was classified as total (T), near total (residual tumor volume 10%). Results: Mean tumor size of entire cohort was 2,53 (range: 0,6-5,8) cm: 2,84 cm in Group A and 2,36 cm in Group B (p=NS). Facial nerve course and position within the cerebellopontine angle did not differ significantly between the two groups. At 6-month follow-up, FN functional outcome was: HBI-II in 69,5% in Group A, versus 96,3% in Group B (pConclusions: Microsurgery of VS in patients aged 40 or less is associated with good functional results, and with high rates of total and near total tumor removal. Patients

Koos grade IV vestibular schwannomas (VS) (maximum diameter3 cm) compress the brainstem and displace the fourth ventricle. Microsurgical resection with attention to the right balance between preservation of function and maximal tumor removal is the treatment of choice. Our series consists of 60 consecutive patients with unilateral VS, operated on from December 2010 to July 2019. All patients underwent microsurgical removal via the retrosigmoid approach. The adherence of VS' capsule to the surrounding nervous structures and the excessive tendency of tumor to bleed during debulking, because of a redundant vascular architecture, was evaluated by reviewing video records. Microsurgical removal of tumor was classified as total (T), near-total (NT: residue5%), subtotal (ST: residue 5-10%), or partial (P: residue10%). Maximal mean tumor diameter was 3,97 cm (SD ± 1,13; range 3,1-5,8 cm). Preoperative severely impaired hearing or deafness (AAO-HNS classes C-D) was present in 52 cases (86,7%). Total or NT resection was accomplished in 46 cases (76,7%), 65,8% in cases with, and 95,4% without tight adhesion of capsule to nervous structures (p0,001). Endoscopic-assisted microsurgical removal of VS in the IAC was performed in 23 patients: in these cases, a T resection was obtained in 78,3% versus 45,9% of microsurgery only (p0,001). The capsule of VS was tightly adherent to nervous structures in 63,3% of patients, whereas hypervascular high-bleeding tumors represented 56,7%. Hearing preservation was possible in 2 out of 8 patients with preoperative class B hearing. At last follow-up, 34 (56,7%) patients had a normal postoperative FN outcome (HBI), 9 (15,0%) were HBII, 8 (13,3%) HBIII, and 9 (15,0%) HBIV. The total NT resection of solid and low-bleeding VS, without tight capsule adhesion, was associated with better FN outcome. Mortality was zero; permanent complications were observed in 2 cases (diplopia, hydrocephalus), transient in 9. Microsurgery of Koos grade IV VS seems to be associated with more than acceptable functional results, with high rate of T and NT removal of tumor. Long-term FN results seem to be worse in patients with cystic Koos grade IV VS, in cases with tight capsule adherences to nervous structures and in high-bleeding tumors.

Vestibular schwannomas (VS) are usually hypovascularized benign tumors. Large VS (Koos grade IV) with unusual vascular architecture are defined as hypervascular (HVVS); the excessive bleeding during microsurgery has a negative impact on results.Forty consecutive patients were operated on for HVVS (group A). A tendency to bleed and adherence of capsule to nervous structures were evaluated by reviewing intraoperative video records. The cisternal facial nerve (FN) position was reported. Microsurgical removal was classified as total, near-total, subtotal, or partial and the MIB-1 index was evaluated in all. FN results were classified according to the House-Brackmann scale.Results of Group A were compared with those of 45 patients operated on for large low-bleeding VS (group B). Mean tumor diameter was 3.81 cm in group A and 3.58 cm in group B; the mean age was 42.4 and 56.3 years, respectively. The mean American Society of Anesthesiologists Physical Status Scale class of group A was 1.67 versus 2.31 of group B (P0.01). Total or near-total resection was accomplished in 76.5% of group A versus 73.3% of group B. Tight capsule adhesion was observed in 67.5% of group A versus 57.8% of group B. Mean MIB-1 was 1.25% and 1.08%, respectively.FN anatomic preservation was possible in 84.6% of group A versus 95.5% of group B; 67.5% of group A had HB grade I or II FN outcome versus 93.3% of group B (Intraoperative video for classification of HVVS was used. Microsurgery of large HVVS was associated with higher (usually transient) complications and recurrence/regrowth rates and poorer FN outcome, especially in patients with tight capsule adhesion.

To retrospectively analyze clinical and surgical data of a consecutive series of 26 patients with unilateral cystic vestibular schwannomas.Tumors were classified as type A (central cyst) and type B (peripheral cyst) and as small (tumor diameter3 cm) and large (tumor diameter3 cm). All patients underwent microsurgical removal via retrosigmoid approach. The course of the facial nerve (FN) was classified as anterior, anterior-inferior, anterior-superior, and dorsal to the tumor's surface.Mean patient age was 53.5 years. Mean tumor size was 3.2 cm. There were 22 cases classified as type A and only 4 as type B. Total or near-total resection (95%) was achieved in 16 cases (61.5%), subtotal removal (90%-95%) was achieved in 9 cases (34.6%), and partial removal (90%) was achieved in 1 case (3.9%). Position pattern of FN was anterior-inferior in 10 cases (38.4%), anterior-superior in 10 cases (38.4%), anterior in 23.2% of 6 cases. At hospital discharge, FN function was House-Brackmann grade I-V in 9 (36%), 10 (38%), 3 (12%), 3 (12%), and 1 (4%) patients; at final follow-up, House-Brackmann grades I, II, III, and IV accounted for 18 (72%), 6 (24%), 1, and 1 cases. During follow-up ranging from 6 months to 10 years, reoperation for growing of residue was never necessary.According to the literature and the results of our series, microneurosurgery of cystic vestibular schwannomas is associated with good outcomes in terms of extent of resection and FN function. In particular, long-term FN function is much more satisfactory than short-term function. In most cases, microsurgery represents the treatment of choice of cystic vestibular schwannomas.

Aims: We performed a retrospective non-randomized study to analyze the results of microsurgery of vestibular schwannomas (VS) using 2μ-Thulium flexible hand-held laser fiber (Revolix jr®). Methods: From September 2010 to November 2018, 180 patients suffering from VS have been operated on with microsurgical technique via retrosigmoid (RS) approach in our Department. From July 2012 to April 2018, tumor resection was performed in 78 cases with the assistance of 2μ-Thulium-fiber hand-held flexible laser. Facial nerve function was assessed with the House-Brackmann (HB) scale preoperatively, 1 week postoperatively, and 6-month after surgery. Results: Overall time from incision to skin suture changed in relation to size of tumor (185–575 min) and was not affected by the use of laser. In 5 out of 78 cases preoperative facial nerve palsy HB2 and in one case HB4 (permanent) was observed. On considering 77 cases (excluding 1 permanent HB4) with a minimum 6-month follow-up, facial nerve preservation rate (HB1) was 92,2%. Hearing preservation rate (AAO-HNS A/B classes) was possible in 17 out of 30 cases (56,7%). Adopting a 0–3-scale, the mean surgeon satisfaction rate of usefulness of laser fiber was 2,75. Conclusions: The use of 2μ-Thulium-fiber hand-held flexible laser in VS-microsurgery seems to be safe and to facilitate tumor resection, especially in “difficult” conditions (e.g., highly vascularized and hard tumors). In this retrospective trial, the good functional outcome following conventional microsurgery had not further improved, nor the surgical time reduced by laser. Focusing its use on “difficult” (large and vascularized) cases may lead to different results in future. Keywords: Acoustic neuroma, Facial nerve preservation, Hearing preservation, Retrosigmoid approach, 2μ-Thulium laser, Vestibular schwannoma

Background and objective: Papaverine hydrochloride is a direct-acting vasodilator used to manage vasospasm during various neurosurgical operations. Transient hearing loss due to vasospasm of Internal auditory artery during Posterior Fossa Microvascular Decompression (MVD) for Typical Trigeminal Neuralgia (TTN) is one of possible complications of this surgical procedure. The aim of this technical note is to underline the potential efficacy of the use of intracisternal diluted papaverine and its proper use. Materials and methods: BAEP is routinely used to monitoring functionality of vestibulocochlear nerve during MVD for TTN. In one patient recently operated on, during arachnoid dissection BAEP showed a lag of V wave of 1 ms, likely due to vasospasm of Internal Auditory Artery (IAA) probably caused by arachnoid traction. Intracisternal injection of pure papaverine without excipients (60 mg/2 ml) diluted in 20 cm3 of 0,9% saline solution (0,3%) was used as a direct therapeutic action to manage vasospasm of IAA artery. Results: Few minutes after the intracisternal injection of diluted papaverine, BAEP's wave V started to get back to normal length and at the end of procedure was the same evoked before starting MVD. After surgery hearing was bilaterally normal. Conclusions: There is large uncertainty about dose-related efficacy and side effects of intracisternal papaverine (iPPV). Dilution of papaverine in saline is recommended to avoid complications. In our practice, in line with the literature, we use 0,3% diluted pure papaverine to prevent hearing loss during MVD for TTN. Keywords: ABR, Hearing preservation, Microvascular decompression, Retrosigmoid approach, Trigeminal neuralgia

BackgroundVestibular schwannomas (VS) are usually hypovascularized. Large VS with unusual vascular architecture are defined hyper-vascular (HVVS); excessive bleeding during microsurgery has negative impact on results. Methods Thirty-two consecutive patients were operated on for HVVS (Group-A). Results were compared with those of 25 patients (Group-B) operated on for large low-bleeding VS. Tendency to bleed and adherence of capsule to nervous structures were evaluated by reviewing video records. Cisternal facial nerve (FN) position was reported. Microsurgical removal was classified as total, near-total, subtotal or partial and MIB-1 index evaluated in all. FN results were classified according the House-Brackmann scale.Results Mean tumor diameter was 3,99cm in Group-A and 3,67 in Group-B; mean age was 42,3 and 58,1 years, respectively. Mean ASA class of Group-A was 1,72 versus 2,48 of Group-B (pConclusions Microsurgery of large HVVS was associated with higher complication and recurrence/re-growth rate and poorer FN outcome, especially in cases with tight capsule adhesion.

In 10-15% of cases of vestibular schwannoma (VS), age at diagnosis is 40 years or less. Little is known about the differences in natural history, surgical findings, and postoperative outcomes of such younger patients as compared to those of greater age. To analyze clinical and surgical and imaging data of a consecutive series of n = 50 patients with unilateral sporadic VS, aged 40 years or younger - separated in a very young group (15-30 years) and a moderately young group (31-40 years). Retrospective case series. Fifty consecutive patients under 40 years of age underwent microsurgical resection of unilateral sporadic VS via the retrosigmoid approach. The study cohort was subdivided into two groups according to the age range: group A, age range 15-30 years (n = 23 patients), and group B, age range 31-40 years (n = 27 patients). The adherence of VS capsule to surrounding nervous structures and the tendency of the tumors to bleed were evaluated by reviewing video records; the course of the FN in relation to the tumor's surface was assessed in each case. Microsurgical removal of tumor was classified as total (T), near total (residual tumor volume 5%), subtotal (residual tumor volume 5-10%), or partial (residual tumor volume 10%). Mean tumor size of entire cohort was 2.53 (range: 0.6-5.8) cm: 2.84 cm in group A and 2.36 cm in group B (p = NS). Facial nerve course and position within the cerebellopontine angle did not differ significantly between the two groups. At 6-month follow-up, FN functional outcome was HBI-II in 69.5% in group A, versus 96.3% in group B (p .001). Hearing preservation was achieved in 60.0% of patients of group A and in 58.3% of group B (p = NS). Total and near-total resection was feasible in 95.6% of cases of group A and in 88.9% of group B (p = NS). Tumor capsule was tightly adherent to nervous structures in 69.6% patients of group A and in 22.2% of group B (p .05). Significant bleeding was encountered in 56.5% of group A tumors, and in 29.6% of group B tumors (p .01). Microsurgery of VS in patients aged 40 or less is associated with good functional results, and with high rates of total and near total tumor removal. Patients 30 years of age have more adherent tumor capsules. Furthermore, their tumors exhibit a tendency to larger sizes, to hypervascularization, to profuse intraoperative bleeding and they present worse long-term functional FN results when compared to patients in their fourth decade of life. Our limited experience seems to suggest that a near total resection in very young VS patients with large tumors should be preferred in adherent and hypervascularized cases, in order to maximize resection and preserve function.

Purpose Koos Grade IV vestibular schwannomas (VS) (maximum diameter >3cm) compress the brainstem and displace the fourth ventricle. Microsurgical resection with attention to the right balance between preservation of function and maximal tumour removal is the treatment of choice.Methods Our series consists of 60 consecutive patients with unilateral VS, operated on from December 2010 to July 2019. All patients underwent microsurgical removal via the retrosigmoid approach. The adherence of VS’ capsule to surrounding nervous structures and the excessive tendency of tumor to bleed during debulking, because of a redundant vascular architecture, was evaluated by reviewing video records. Microsurgical removal of tumor was classified as total (T), near-total (NT: residue10%).Results Maximal mean tumor diameter was 3,97cm (SD±1,13; range 3,1-5,8cm). Preoperative severely impaired hearing or deafness (AAO-HNS Classes C-D) was present in 52 cases (86,7%). Total or NT resection was accomplished in 46 cases (76,7%), 65,8% in cases with and 95,4% without tight adhesion of capsule to nervous structures (pConclusions Microsurgery of Koos Grade IV VS seems to be associated with more than acceptable functional results, with high rate of T and NT removal of tumor. Long-term FN results seem to be worse in patients with cystic Koos Grade IV VS, in cases with tight capsule adherences to nervous structures and in high-bleeding tumors.

Background: Permanent hearing loss after posterior fossa microvascular decompression (MVD) for typical trigeminal neuralgia (TTN) is one of the possible complications of this procedure. Intraoperative brainstem auditory evoked potentials (BAEPs) are used for monitoring the function of cochlear nerve during cerebellopontine angle (CPA) microsurgery. Level-specific (LS)-CE-Chirp® BAEPs are the most recent evolution of classical click BAEP, performed both in clinical studies and during intraoperative neuromonitoring (IONM) of acoustic pathways during several neurosurgical procedures. Methods: Since February 2016, we routinely use LS-CE-Chirp® BAEPs for monitoring the function of cochlear nerve during CPA surgery, including MVD for trigeminal neuralgia. From September 2011 to December 2018, 71 MVDs for TTN were performed in our department, 47 without IONM of acoustic pathways (Group A), and, from February 2016, 24 with LS-CE-Chirp BAEP (Group B). Results: Two patients of Group A developed a permanent ipsilateral anacusia after MVD. In Group B, we did not observe any permanent acoustic deficit after surgery. In one case of Group B, during arachnoid dissection, intraoperative LS-CE-Chirp BAEP showed a temporary lag of V wave, resolved in 5 min after application of intracisternal diluted papaverine (0.3% solution without excipients). Conclusion: MVD is widely considered a definitive surgical procedure in the management of TTN. Even though posterior fossa MVD is a safe procedure, serious complications might occur. In particular, the use of IONM of acoustic pathways during MVD for TTN might contribute to prevention of postoperative hearing loss.

The efficacy of endoscopic techniques in the surgical management of intracanalicular vestibular schwannomas (ICVSs) has been underlined in recent studies. An endoscopic- assisted retrosigmoid approach (EARSA) appears to be particularly suitable for achieving complete resection of an ICVS. In this study, we describe the surgical treatment of 3 cases of ICVS with an EARSA, highlighting the advantages and limitations of flexible endoscopy in accomplishing a safe radical resection with hearing preservation. Three patients with an ICVS underwent surgery via a flexible endoscopic-assisted microneurosurgical retrosigmoid approach. Flexible endoscopic assistance allowed the identification of residual tumor located in the most lateral portion of the fundus of the internal auditory canal in all cases. Endoscopic controls and further microsurgical resection were attempted, and complete surgical resection was achieved in all cases without the occurrence of postoperative facial or auditory nerve dysfunction. Flexible endoscopy appears to be particularly useful and safe in the surgical management of ICVS by microneurosurgery via an EARSA.

Background and objectives Decision-making regarding the therapy of vestibular schwannoma (VS) changed over the last decades, during which curative microsurgery has been promoted. Goals of VS microsurgery are: extensive resection, facial nerve (FN) preservation and, in selected cases, hearing preservation (HP). The aim of this study is to evaluate postoperative HP with reference to tumor size in patients operated on with Level Specific (LS)-CE-Chirp® ABR monitoring. Patients and methods Twentyfive consecutive patients with socially useful hearing (SUH) underwent VS microneurosurgery by retrosigmoid (RS) approach. Selection criteria were: pure tone audiogram 50% (50/50 criterion; AAO-HNS class A-B). In relation to maximum diameter, we identified 2 size-groups: A) ≤2cm (13 cases); B) >2cm (12 cases). HP attempt was assisted by intraoperative ABR evoked by LS CE-Chirp® acoustic stimuli. Results Mean age was 44,3 years (20–64); average maximum diameter 2,04cm (8 40mm). Total and nearly-total (>95%) resection was possible in all. Mortality and major morbidity were zero. In all, FN was anatomically and functionally preserved; in 10 an incomplete FN deficit (House-Brackmann II and III) was followed by complete recovery (House-Brackmann I). SUH preservation rate was 52%, with significant differences in relation to size: 61,5% group A and 41,7% group B (p = 0,014). Postoperative AAO-HNS C (serviceable) hearing was observed in 36%, deafness in 12%. Conclusion Microsurgery represents a valid therapeutic option for small growing VS with SUH. Our data confirm that RS removal of VS with intraoperative ABR monitoring allows good rate of SUH preservation, especially if maximum diameter does not exceed 2cm. LS-CE-Chirp ABR represent a safe and effective method for monitoring cochlear nerve, with fast and clear intraoperative neurophysiological feedback.

The extreme lateral infrajugular transcondylar-transtubercular exposure (ELITE) is a surgical approach developed in the late 1980s by Prof. T. Fukushima and represents the dorsolateral inferior skull base procedure of choice to approach lesion located ventrolaterally at the level of the craniocervical junction (CCJ). This approach consist in a suboccipital craniotomy/craniectomy with partial condylectomy and jugular tubercule drilling that can be extended providing for subtotal condylectomy and vertebral artery transposition. The “limited” variation of the ELITE approach consist in a lateral suboccipital craniectomy opening the foramen magnum and removal of at least half of the posterior arch of the atlas without condyle drilling. This surgical technique was recently demonstrated to be particularly suitable for the surgical management of spinal tumor located ventrolaterally in the upper cervical spine. This operative video illustrates step-by-step the surgical technique adopted for the microsurgical resection of a C1-C2 intradural schwannoma located antero-laterally ( Video 1 ). ELITE approach offers a wide and adequate exposure and access to the CCJ, allowing direct visualization and access to the tumor with minimal neural manipulations, early detection of the vertebral artery and, for tumor located at C1-C2 level, without drilling the occipital condyle. In our experience, ELITE procedure is the preferred surgical approach for resection of tumors located ventrally or ventrolaterally to the first 2 cervical levels.

Background Cavernous malformations (CM) in the cerebellopontine angle (CPA) are rare, and most of them are solid and extend from the internal auditory canal into the CPA. In contrast, cystic CM arising in the CPA and not involving the internal auditory canal and dura of the skull base are extremely rare. The authors present an uncommon large cystic progression of a cavernous malformation at the level of the trigeminal root entry zone evolving to severe trigeminal neuralgia and brainstem compression. Methods A 62-year-old female presented a sudden onset of left trigeminal neuralgia, caused by a large cystic lesion at the level of the root entry zone of the left 5th nerve. On neurological examination, she showed slight gait ataxia and hypoesthesia on the left hemiface (on the first and second trigeminal branches). Other cranial nerves were in order. Magnetic resonance imaging showed a large cystic intracranial mass, with a small solid portion, leading to brainstem compression. Results Microsurgical removal of the lesion was performed via retrosigmoid approach, with intraoperative monitoring of somato-sensory evoked potentials, facial, and cochlear nerves. The posterior-medial portion of the lesion was solid, whereas the main portion was cystic, containing xanthochromic fluid. The small solid lesion continued with a thin capsule of a large cyst adherent to brainstem, cerebellar hemisphere, and trigeminal nerve entry zone. A big draining vein arising from the solid part of the lesion runned parallel to brainstem. The mass was piecemeal totally removed.After surgery the patient recovered both left trigeminal neuralgia and hypoesthesia; ataxia was significantly relieved too. Postoperative magnetic resonance imaging confirmed the total removal. Histopathological features were consistent with a CM. At 6-month follow-up, patient's symptoms at the presentation had resolved. Conclusion The authors present a very rare patient of large cystic cavernous malformation at the level of the trigeminal root entry zone presenting with sudden onset of trigeminal neuralgia. Even if it has not established imaging features, a cystic cavernoma of the cerebello-pontine angle may be suspected when a cystic mass is present, not involving the internal acoustic meatus nor the skull base dura mater. Careful microneurosurgical technique and monitoring of cranial nerves allow good long-term results.

Objective The incidence of typical trigeminal neuralgia (TN) increases with age, and neurologists and neurosurgeons frequently observe patients with this disorder at age 65 years or older. Microvascular decompression (MVD) of the trigeminal root entry zone in the posterior cranial fossa represents the etiological treatment of typical TN with the highest efficacy and durability of all treatments. This procedure is associated with possible risks (cerebellar hematoma, cranial nerve injury, stroke, and death) not seen with the alternative ablative procedures. Thus the safety of MVD in the elderly remains a topic of discussion. This study was conducted to determine whether MVD is a safe and effective treatment in older patients with TN compared with younger patients. Methods In this retrospective study, 28 patients older than 65 years (elderly cohort: mean age 70.9 ± 3.6 years) and 38 patients Results At a mean follow-up 26.0 ± 5.5 months, 25 patients of the elderly cohort (89.3%) reported a good outcome without the need for any medication for pain versus 34 (89.5%) of the younger cohort. Twenty-three elderly patients with type 1 TN were compared with 30 younger patients with type 1 TN, and no significant difference in outcomes was found (p > 0.05). Five elderly patients with type 2a TN were compared with eight younger patients with type 2a TN, and no significant difference in outcomes was noted (p > 0.05). There was one case of cerebrospinal fluid leak and one of a cerebellar hematoma, both in the younger cohort. Mortality was zero in both cohorts. Conclusions On the basis of our experience and the international literature, age itself does not seem to represent a major contraindication of MVD for TN.

New details about the role of proinflammatory pathways in the molecular pathogenesis of vestibular schwannoma have inspired the researchers to experiment aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of the tumor. Encouraging evidences have been reported in clinical studies. However, a double-blind, placebo-controlled, randomized trial is still missing and needed to ultimately address the efficacy of aspirin as a cytostatic on vestibular schwannoma and its correct posology. Second and even more ambitious target would be application of aspirin as a cytostatic for secondary prevention of tumor growth. In the personal experience, nine patients have undergone subtotal tumor resection and have been prescribed postoperative aspirin off-label with the purpose of avoiding recurrences. The maximum follow-up period has been 47 months, and only the first patient needed reoperation due to tumor regrowth; the remaining eight patients are being followed up and show stable tumors.

Hydroxyapatite cement (HAC) is an osteoconductive material that serves as a scaffold over and inside which bone can grow without intervening fibrous tissue. With micropore diameters of 2–5 nm, HAC is highly resistant to infection. Whether it should be used as the sole bone substitute during cranioplasty or as an adjunct to other materials, it is still a matter of debate, and no direct answer really exists. At our institution, bone flap is always repositioned and fixed with titanium screws prior to layering the HAC. As reconstructive retrosigmoid cranioplasty was combined with an underlay hourglass-shaped autologous pericranium duraplasty, no postoperative wound infections or meningitis were observed nor were clinically significant cerebrospinal fluid (CSF) leaks reported. In the perspective of reducing the postoperative CSF leak rate as much as possible, it is advisable to focus the upcoming research not only on cranioplasty but also on the combination duraplasty-cranioplasty, which yielded very good results in our experience.

CSF fistulas into the soft tissues of the skull base can cause wound breakdown and/or pseudomeningocele, which often becomes very painful and debilitating. In addition, drainage of spinal fluid from the skin increases the risk for surgical site infections and meningitis. Diverse techniques for posterior cranial fossa dural reconstruction and closure have been reported: application of synthetic dural patches, incorporation of autologous tissues, and augmentation with “muscle plugs.” Even if a variety of dural substitutes is currently available, many articles in the literature suggest that autologous materials are preferable compared to nonautologous substitutes. Our group reported the use of autologous pericranium harvested during the opening step of retrosigmoid approach, inserted and stitched as an underlay hourglass-shaped plug for dural closure. We did not observe any surgical site infections, meningitis, CSF leaks, or new neurological symptoms using properly this dural closure technique.

One hundred sixty consecutive patients (mean age, 49.9 years) were operated at San Filippo Neri Hospital, Rome, between September 2010 and April 2018. Mean tumor size was 23.3 mm. One hundred thirty-five patients (84.4%) had completely preserved facial nerve function (HB 1) before surgery; 56 (35%) patients had preoperative serviceable hearing (AAO-HNS classes A/B). Retrosigmoid approach was performed in all the cases except for one, wherein the patient underwent a translabyrinthine approach. The total or near-total (thin capsule residue left on the brainstem) resection rate was obtained in majority of cases. In the last 14 surgical procedures, a flexible endoscope was employed for final check in the IAC. At 6 months after surgery, 149 (93.7%) patients had HB 1 or facial nerve function. Among 56 patients who had serviceable hearing before surgery, 35 retained it, thus yielding a hearing preservation rate of 62.5%. In 63 procedures, diluted topical papaverine was used for improving the blood flow in microvasculature of cranial nerves.

The current strategy in vestibular schwannoma surgery dictates early intraoperative identification of the facial nerve by means of intraoperative monitoring. Imaging studies designed to trace the course of the facial nerve preoperatively should theoretically enhance surgical safety. The use of diffusion tensor tractography (DTT) for nerve tracking has evolved as a reliable technique in this regard. The latest systematic review available in the literature showed that complete tracking of the nerve’s course was obtained in 96.6% of cases and that surgical concordance with the preoperative DTT findings was obtained in 90.7%. The authors deemed preoperative DTT for facial nerve identification a useful adjunct in the surgical planning for large tumors (>2.5 cm). The application of tractography to detailed morphological reconstruction of the cranial nerves is a recent technology; therefore, it has potential limitations. These include a limited ability to distinguish the fibers of VII and VIII nerves, which could be overcome by combining DTT with specific MRI sequences.

Using a retrosigmoid approach, the internal auditory meatus cannot be completely opened to expose the fundus in order to preserve the superior and posterior semicircular canals. Therefore, a straight microscopic view cannot provide an adequate visualization of the most lateral part of the internal auditory canal (IAC). Endoscope assistance provides optimal exposure of the fundus of the IAC and improves the ability to evaluate the extent of resection intraoperatively. Our group reported the successful surgical treatment (total resection) of three cases of intracanalicular vestibular schwannomas operated on with an endoscopic-assisted retrosigmoid approach by means of a flexible endoscope (4-mm × 65-cm, Karl Storz, Inc.). The main advantage of the flexible endoscope is the possibility to orient the endoscopic tip directly into the IAC to obtain an optimal visualization of the fundus. As opposed to rigid devices, the flexible endoscope has to be manipulated with two hands. However, this limitation can be easily overcome through good cooperation and synchronicity between the operator and the assistant.

The most important instruments for vestibular schwannoma surgery can be grouped as follows: standard microsurgical instruments, electronic microsurgical devices, endoscopes, and intraoperative neurophysiological monitoring (IONM) devices. Standard—i.e., mechanical—microsurgical instruments are used for tumor dissection, fragmentation, and piecemeal resection. Electronic microsurgical devices consist of bipolar forceps, used to achieve precise hemostasis; handheld 2μ-thulium flexible laser fiber, which can be used for hemostasis, capsule and dural incision and vaporization, and tumor debulking; and ultrasonic aspirator, mainly used for tumor debulking and internal auditory canal (IAC) opening. The endoscopes allow direct observation of the lateral extremity of the IAC and enable the surgeon to visualize and remove the deepest tumor remnants. IONM devices stimulate both facial and cochlear nerves and detect their responses so as to offer real-time monitoring of their functional state during surgery.

Silent cerebral vasospasm following surgical resection of vestibular schwannomas is much more common than previously thought. This might mean that the cerebral circulation shows a high reactivity to surgical trauma, and it can be hypothesized that this happens not only in elastic and muscular arteries but also in arterioles—and especially those within the cerebellopontine angle. From this perspective, prevention of vasospasm is useful for microvascular protection of the cranial nerves. Papaverine is known to be a potent vasodilator directly acting on smooth muscle and causing it to relax. Intra-arterial administration of papaverine has been used to treat arterial vasospasm after aneurysmal subarachnoid hemorrhage. When applied topically, it acts as a smooth muscle relaxant to break intraoperative vasospasm. The most important side effects of topical papaverine in vestibular schwannoma surgery are transient palsies of facial and cochlear nerves. It has been proposed that intracisternal papaverine at a concentration of 0.3% would be reasonably safe.

Vestibular schwannomas (also known as acoustic neuromas) are intracranial tumors arising from Schwann cells, which form the myelin sheath around the vestibulocochlear bundle. Vestibular schwannomas account for 5–10% of intracranial tumors and are the most common neoplastic lesions in the cerebellopontine angle. The main risk factor is the exposure to radiation and, as most recently ascertained, leisure noise. They are classified as WHO grade I tumors and have a locally compressing effect rather than an infiltrative tendency. The site of origin is the inferior vestibular nerve in 70% of cases and the superior vestibular nerve in 20%. The most common symptoms are hearing loss (95% of patients) and tinnitus (63%), usually with a chronic onset. The diagnostic workup requires audiometry and magnetic resonance imaging with gadolinium contrast to confirm the clinical suspicion. Different grading systems have been proposed to stage tumor progression, Samii’s classification being one of the most commonly used.

Eight video clips are commented, showing the surgical steps of a standard retrosigmoid approach to a case of right-sided vestibular schwannoma, grade T4a according to Samii’s classification. Keyhole craniotomy is performed and followed by dural incision. Facial nerve is then located, and the capsule is incised by means of thulium laser fiber. The internal auditory canal is opened, and the contents are dissected in order to preserve the facial nerve. Flexible endoscopy final check in the internal auditory canal is shown in the case of a left-sided intracanalicular vestibular schwannoma, grade T1.

The rationale for laser use in tumor resection is both to allow for “no-touch” cutting and for tissue debulking, with hemostatic benefit. Laser surgery, in general, has shown various advantages, such as reduction of mechanical trauma and intraoperative bleeding. Three types of laser have been successfully used in vestibular schwannoma surgery, potassium titanyl phosphate (KTP-532), CO2, and the novel 2μ-thulium lasers, which has been deemed safe especially in “difficult” conditions (e.g., highly vascularized and hard tumors).

Vestibular schwannomas (VS) mainly arise from either the superior (SVN) or the inferior vestibular nerve (IVN). Preoperative vestibular testing in patients affected by VS can be useful to predict which one of the vestibular nerves the tumor arises from. The relevance of identifying the nerve of origin lies in its prognostic factor for hearing preservation after surgery, with tumors arising from the (SVN) having a much higher hearing preservation rate. Diverse studies in the literature have tested the correlation between abnormal vestibular testing results and the nerve of origin of VSs; the techniques experimented in such context are posturography, vestibular evoked myogenic potentials (VEMPs), caloric test (always in combination with VEMPs), and video head impulse test (vHIT). vHIT has yielded promising results, with a positive predictive value ranging from 89.5 to 100%, so that the pattern of semicircular canal dysfunction on vHIT has been proposed to have a localizing value to identify the nerve of origin in VSs.

To investigate the variation in the position and course of the facial nerve (FN) in patients undergoing vestibular schwannoma (VS) microsurgery by the keyhole retrosigmoid approach and the relationship between FN position and postoperative facial results.The series consists of 100 patients who underwent VS microsurgery during a 5-year period in whom the position and course of the FN could be confirmed by direct stimulation. The course of the FN was classified into 4 patterns according to its position: anterior (ventral) surface of the tumor (A), anterior-superior (AS), anterior-inferior (AI), and dorsal (D).The distribution of patterns was as follows: AS in 48 cases, A in 31, AI in 21, and D in zero. For tumors1.5 cm, the AS pattern was most common (68.4%). For tumors ≥1.5 cm, the proportion of A and AI positions increased (31.4% and 25.5%). Significant differences were observed between position and course patterns of the FN and postoperative nerve results. Patients with AS and AI patterns had better House-Brackmann FN function compared with patients with the A pattern (P0.05). Moreover, in tumors 3.0 cm, the FN tended to adhere strongly to the tumor capsule, and postoperative facial deficits were more frequent (P0.05).The AS pattern was most common for smaller VSs. The A position and course and adhesion of the FN to the tumor capsule were the 2 factors most strongly associated with worse postoperative FN result.

Cavernous angiomas originating in the internal auditory canal are very rare. In the available literature, only 65 cases of cavernomas in this location have been previously reported. We describe the case of a 22-year-old woman surgically treated for a cavernous hemangioma in the left internal auditory canal, mimicking on preoperative magnetic resonance imaging MRI an acoustic neuroma. Neurological symptoms were hypoacusia and dizziness. The cavernous angioma encased the seventh and, partially, the eighth cranial nerve complex. A "nearly total" removal was performed, leaving a thin residual of malformation adherent to the facial nerve. Postoperative period was uneventful; hearing was unchanged, but the patient had a moderate inferior left facial palsy (House-Brackmann grade II) slightly improved during the following weeks. On the basis of the observation of this uncommon case, we propose a revision of the literature and discuss clinical features, differential diagnosis, and treatment.

Skull base tumors arising from the middle cranial fossa and invading of the infratemporal fossa (ITF) and middle cranial fossa are challenging for neurosurgeons, because of complex anatomy and critical neurovascular structure involvement. The first pioneering ITF approaches resulted in invasive procedures and carried a high rate of surgical morbidity. However, the acquisition of deep anatomical knowledge, and the development operative skills and reconstruction techniques allowed surgeons to achieve total or near total resection of many ITF lesions with a low morbidity rate. In Video 1 we illustrate our technique for the anterior ITF approach for the surgical treatment of a middle cranial fossa meningioma invading the ITF. This surgical video describes the anterior ITF approach in 2 steps. First, a standard extradural middle fossa approach subtemporal approach is performed on a cadaveric specimen, illustrating the anterior extension to the cavernous sinus. Second, the anterior ITF approach is performed for the surgical treatment of a temporal lobe meningioma with extension to the anterior ITF. This technique provides a minimally invasive approach for treating middle fossa lesions with anterior ITF extension.

OBJECT: Incidence of typical trigeminal neuralgia (TN) increases with age and neurologists and neurosurgeons frequently observe patients with this disorder at the age of 65 or more. Microvascular decompression (MVD) of the trigeminal root entry zone in posterior cranial fossa is the only etiological therapy for typical TN with the highest efficacy and durability of all treatments. This procedure is associated with possible risks (cerebellar hematoma, cranial nerve injury, stroke, and death) not seen with the alternative ablative procedures. Thus, the safety of MVD in the elderly remains non definitively demonstrated. This study was conducted to determine whether MVD is a safe and effective treatment in elderly patients with TN in comparison to younger patients.METHODS: In this retrospective study, 25 patients older than 65 (mean age 70.1 ± 3.7 years) and 32 aging 0.05). Five elderly patients with Type 2a TN were compared with 8 younger patients with Type 2a TN, and no significant difference in outcomes was noted (p > 0.05). There was one case of CSF leak and one case of cerebellar hematoma both in the younger cohort. Mortality was zero in both groups.CONCLUSIONS: On the basis of our experience and of the international literature, age itself seems not to represent a major contraindication against MVD for TN. Keywords: Elderly, Microvascular Decompression, Retrosigmoid approach, Trigeminal neuralgia, Tic douloureux