The use of cochlear-enhancement imaging to predict hearing preservation following vestibular schwannoma removal.

BACKGROUND: Hearing preservation is challenging for patients after the removal of large vestibular schwannomas (VSs). Here, using preoperative magnetic resonance (MR) imaging, we investigated the significance of cochlear enhancement (CE) for predicting postoperative hearing preservation. METHODS: Between January 2014 and December 2019, 34 VS-patients with serviceable hearing underwent tumor-removal surgery using a retrosigmoid approach. The presence or absence of CE using both T2-weighted and gadolinium-enhanced T1-weighted MR images was assessed in VS patients using the pixel-analysis method. Segmented volumetric analyses were also performed using GrowCut 3D slicer software. RESULTS: There were 17 patients (50%) without CE and 17 (50%) with CE. Ten of the 17 non-CE patients (58.8%) had postoperative hearing preservation. In contrast, only 3 of the 17 patients with CE (17.6%) had postoperative hearing preservation. There were no significant tumor-characteristic differences between the two groups. The presence of CE on both the T2-weighted and the gadolinium-enhanced T1-weighted MR images correlated significantly with postoperative hearing outcomes (p = 0.032). Only pure-tone averages were significantly different between the two groups (p = 0.049). CONCLUSIONS: Preoperative serviceable hearing is likely to be preserved after surgery in non-CE VS patients. Preoperative CE assessment using MR imaging may be a useful predictor for postoperative hearing outcomes in VS patients.

Endoscopic Endonasal Approach to the Anteromedial Temporal Fossa and Mobilization of the Lateral Wall of the Cavernous Sinus Through the Inferior Orbital Fissure and V1-V2 Corridor: An Anatomic Study and Clinical Considerations.

OBJECTIVE: The aim of this study was to identify key anatomic landmarks useful in gaining access to the anteromedial temporal region via the corridor formed by the inferior orbital fissure (IOF), the ophthalmic branch of the trigeminal nerve (V1), and the maxillary branch of the trigeminal nerve (V2) via an endoscopic endonasal approach (EEA). METHODS: An anatomic dissection of 6 cadaver heads was performed to confirm the feasibility and applicability of an EEA for accessing the anteromedial temporal region. RESULTS: After middle turbinectomy, the lateral recess of the sphenoid sinus was opened, the orbital apex was exposed, and the posterior wall of the maxillary sinus was removed, in sequence. The IOF and the pterygopalatine fossa (PPF) were then identified. After opening the foramen rotundum (FR) and removing the bony structure between the FR, V2 was transposed downward. The orbital muscle of Müller was removed. The PPF was mobilized downward exposing the greater wing of the sphenoid bone (GWS). The GWS between V1 and V2 was drilled, therefore exposing the temporal dura. With blunt dissection, the medial temporal dura was peeled away from the cavernous sinus to increase access to the anteromedial temporal region. CONCLUSIONS: The anteromedial temporal fossa was exposed by drilling the V1-V2 triangle corridor via an EEA. Endoscopic endonasal exposure of the anteromedial temporal fossa is feasible and requires limited endonasal work. This approach may be considered as an alternate surgical corridor to the temporomesial lobe that offers the advantages of a direct route with less temporal lobe retraction.

Sandwich technique using fibrin-coated collagen fleece for sellar reconstruction in large dural defects during transsphenoidal surgery.

PURPOSE: Various surgical methods to prevent intraoperative and postoperative cerebrospinal fluid (CSF) leaks during transsphenoidal approach (TSA) surgeries have been reported, but surgical techniques to address large dural defects have been less thoroughly investigated in the literature. The authors retrospectively evaluated the usefulness of the sandwich technique using fibrin-coated collagen fleece (TachoSil) to prevent intraoperative CSF leakage from large dural defects in TSA surgery. METHODS: In total, 101 cases of intraoperative CSF leaks were observed among 465 patients who underwent TSA surgery at a single university hospital between 2002 and 2014. Among them, cases with Grade 3 intraoperative CSF leakages and large diaphragmatic/dural defects were reconstructed via the sandwich technique using TachoSil or via the conventional technique using simple intrasellar packing with fat or synthetic materials, and these cases were enrolled in this study. RESULTS: A total of 28 cases with Grade 3 intraoperative CSF leakages were identified and analyzed. The sandwich technique using TachoSil was applied in 13 cases, and the conventional technique was applied in 15 cases. The postoperative CSF leakage was significantly decreased by the sandwich technique as compared to the conventional technique (retrospectively, 0 cases vs. 4 cases (30.8%); P=0.044). CONCLUSION: The sandwich technique using TachoSil can effectively prevent CSF leakage in cases with large dural defects during TSA surgery.

Single-Stage Operation for Giant Schwannoma at the Craniocervical Junction with Minimal Laminectomy: A Case Report and Literature Review.

Here we report a single-stage operation we performed on a patient with a large schwannoma that extended from the lower clivus to the cervico-thoracic junction caudally. A number of authors have previously performed multilevel laminectomy to remove giant schwannomas that extend for considerable length. This technique has caused cervical instability such as kyphosis or gooseneck deformity on several occasions. We removed the tumor with a left lateral suboccipital craniectomy with laminectomy only at C1 and without any subsequent surgery-related neurologic deficits. However, this technique requires meticulous preoperative evaluation on existence of Cerebrospinal fluid (CSF) cleft between the tumor and spinal cord on magnetic resonance imaging, of tumor origin located at the upper cervical root, and of detachment of tumor from the origin site.

Surgical Treatment for Falcotentorial Meningiomas.

Among intracranial meningiomas, falcotentorial meningiomas, occurring at the junction of the falx cerebri and tentorial dural folds, are extremely rare. Because of their deep location, they are surrounded by critical structures, and have been regarded as one of the most challenging lesions for surgical treatment. In this study, we describe our surgical strategy for falcotentorial meningiomas and provide a review of our experience.

Change of lumbar motion after multi-level posterior dynamic stabilization with bioflex system : 1 year follow up.

OBJECTIVE: This study examined the change of range of motion (ROM) at the segments within the dynamic posterior stabilization, segments above and below the system, the clinical course and analyzed the factors influencing them. METHODS: This study included a consecutive 27 patients who underwent one-level to three-level dynamic stabilization with Bioflex system at our institute. All of these patients with degenerative disc disease underwent decompressive laminectomy with/without discectomy and dynamic stabilization with Bioflex system at the laminectomy level without fusion. Visual analogue scale (VAS) scores for back and leg pain, whole lumbar lordosis (from L1 to S1), ROMs from preoperative, immediate postoperative, 1.5, 3, 6, 12 months at whole lumbar (from L1 to S1), each instrumented levels, and one segment above and below this instrumentation were evaluated. RESULTS: VAS scores for leg and back pain decreased significantly throughout the whole study period. Whole lumbar lordosis remained within preoperative range, ROM of whole lumbar and instrumented levels showed a significant decrease. ROM of one level upper and lower to the instrumentation increased, but statistically invalid. There were also 5 cases of complications related with the fixation system. CONCLUSION: Bioflex posterior dynamic stabilization system supports operation-induced unstable, destroyed segments and assists in physiological motion and stabilization at the instrumented level, decrease back and leg pain, maintain preoperative lumbar lordotic angle and reduce ROM of whole lumbar and instrumented segments. Prevention of adjacent segment degeneration and complication rates are something to be reconsidered through longer follow up period.