Combined Anterior (Kawase) and Posterior Petrosectomy (pre-sigmoid/ retro-labyrinthine) for Resection of Post-Radiosurgery Recurrent Cavernous Sinus and Meckel's cave Meningioma; with Simultaneous Microvascular Decompression for Trigeminal Neuralgia: 2 Dimensional Operative video, and Review of Literature.

BACKGROUND: A 70-year male had previous gamma knife (GK) for left cavernous sinus and Meckel's cave meningioma for facial numbness. He presented 11 years later with facial pain (both typical and atypical) and worsening numbness. OBSERVATIONS: MRI showed tumor growth and an infratentorial extension. FIESTA MRI showed left superior cerebellar artery (SCA) contact with the V nerve root entry zone (REZ) accounting for Type 1/ lancinating pain. After discussing available options, he opted for surgery. Lumbar drain, and a middle fossa anterior petrosectomy (Kawase) combined with posterior petrosectomy (retrolabyrinthine) approach was employed to perform tumor debulking along with microvascular decompression (mobilization of SCA). SSEP, BAERS, MEP, V nerve monitoring were performed. Fat graft was used for multilayered closure. He experienced resolution of both type 1 & type 2 facial pain, improvement in sensation in V3. Symptomatic improvement was recorded at 11 months follow up. LESSONS: The combined skull base approach provided visualization of the entire length of V nerve (Cisternal, Meckel's cave, V2 and V3) allowing for decompression at various points to achieve relief of both types of facial pain. The patient provided consent for use of his images and operative video for publication.

Trigeminal Neuralgia from Simultaneous Compression by Cerebellopontine Angle Epidermoid and Duplicated Superior Cerebellar Artery Loop: Two-Dimensional Operative Video of Resection and Microvascular Decompression with Endoscopic Assistance.

A 51-year-old woman presented with 2 years of progressive left facial pain and numbness in maxillary nerve and mandibular nerve distributions. Symptoms were refractory to increasing doses of carbamazepine and gabapentin. Magnetic resonance imaging showed a left cerebellopontine angle nonenhancing mass, with diffusion restriction causing trigeminal nerve compression. Fast imaging employing steady-state acquisition sequences revealed a superior cerebellar artery loop in the angle between cranial nerve V and pons. The patient agreed to resection of the mass and microvascular decompression. Retrosigmoid craniotomy was performed with sensory/motor, and facial-auditory nerves' monitoring. The mass was densely adherent to cranial nerves VII-X and the anterior inferior cerebellar artery, causing compression at the root entry zone of the trigeminal nerve. It was carefully dissected off these structures; pathology confirmed an epidermoid. A large bony tubercle obscured visualization; therefore, a 30° endoscope was used. The tubercle was drilled, and remnant portions of the mass were removed. During mobilization of the superior cerebellar artery loop, it was found to be duplicated, and polytef (Teflon) pledgets were placed for microvascular decompression. The trigeminal nerve was thus discovered intraoperatively to be trapped simultaneously between the duplicated superior cerebellar artery loop from above and the epidermoid from below. Pain relief was immediate; at 12-month follow-up, the patient was pain-free, she had minimal numbness around the angle of the lip, and medications were discontinued. Facial nerve function and hearing were intact. A pure endoscopic approach is minimally invasive with a smaller incision and has been described for microvascular decompression for trigeminal neuralgia. Cerebrospinal fluid leak rates are expected to be lower. This technique has a steep learning curve and could pose a significant challenge for resection of lesions densely adherent to neurovascular structures. A pure microscopic approach generally involves a larger incision and can be better suited for resection of cerebellopontine angle lesions where bimanual dissection would be necessary. Visualization around corners in the presence of large bony protuberances (e.g., large suprameatal tubercle) around vessels and nerves in the depths is a drawback. Combining microscopic surgery with endoscopic assistance (especially angled endoscope) negates the disadvantages of either method alone, allowing for visualization around structures in the depths of the cerebellopontine angle where microscope lighting may be reduced, and provides a means to achieve gross total resection of tumor hidden from view.

Hemifacial Spam: Endoscopic Assistance in Facial Nerve Decompression With Lateral Spread Response Corroboration: 2-Dimensional Operative Video.

This video depicts the case of a 48-yr-old female with 3 yr of progressive left hemifacial spasm (HFS) refractory to medication. Magnetic resonance imaging showed a large anterior inferior cerebellar artery (AICA) and also a labyrinthine artery loop around the facial nerve (FN) root exit zone. A large bony eminence was also noted in the superior and lateral aspects of the porous acousticus (PA). She preferred surgery if "cure" was possible in lieu of Botox injections. A left retro sigmoid craniotomy was performed with brainstem auditory evoked responses (BAERs) and FN monitoring along with lateral spread response (LSR) assessment. The large bony prominence was drilled in its lateral aspect. Despite this, visualization was still limited and therefore we utilized a 30-degree-angled endoscope to observe the vessels caudal and cranial to the FN. This view prompted us to then drill further at the PA to decompress the FN as well as mobilize the labyrinthine artery away from the nerve. The LSR showed a dramatic improvement when FN decompression was accomplished, and then a further improvement with arterial mobilization and Teflon pledget placement. The BAERS remained at baseline throughout. FN function and hearing were intact on postoperative clinical assessment. Her symptomatic improvement was recorded at 12 mo after surgery. This video illustrates a more complex case of microvascular decompression with skull base concepts and techniques. The patient provided consent for the procedure and use of her images and operative video for publication.

Expanding the endoscopic transpterygoid corridor to the petroclival region: anatomical study and volumetric comparative analysis.

OBJECTIVE The endoscopic endonasal transmaxillary transpterygoid (TMTP) approach has been the gateway for lateral skull base exposure. Removal of the cartilaginous eustachian tube (ET) and lateral mobilization of the internal carotid artery (ICA) are technically demanding adjunctive steps that are used to access the petroclival region. The gained expansion of the deep working corridor provided by these maneuvers has yet to be quantified. METHODS The TMTP approach with cartilaginous ET removal and ICA mobilization was performed in 5 adult cadaveric heads (10 sides). Accessible portions of the petrous apex were drilled during the following 3 stages: 1) before ET removal, 2) after ET removal but before ICA mobilization, and 3) after ET removal and ICA repositioning. Resection volumes were calculated using 3D reconstructions generated from thin-slice CT scans obtained before and after each step of the dissection. RESULTS The average petrous temporal bone resection volumes at each stage were 0.21 cm3, 0.71 cm3, and 1.32 cm3 (p < 0.05, paired t-test). Without ET removal, inferior and superior access to the petrous apex was limited. Furthermore, without ICA mobilization, drilling was confined to the inferior two-thirds of the petrous apex. After mobilization, the resection was extended superiorly through the upper extent of the petrous apex. CONCLUSIONS The transpterygoid corridor to the petroclival region is maximally expanded by the resection of the cartilaginous ET and mobilization of the paraclival ICA. These added maneuvers expanded the deep window almost 6 times and provided more lateral access to the petroclival region with a maximum volume of 1.5 cm3. This may result in the ability to resect small-to-moderate sized intradural petroclival lesions up to that volume. Larger lesions may better be approached through an open transcranial approach.

Aortic arch origin of the left vertebral artery: An Anatomical and Radiological Study with Significance for Avoiding Complications with Anterior Approaches to the Cervical Spine.

Complications from anterior approaches to the cervical spine are uncommon with normal anatomy. However, variant anatomy might predispose one to an increased incidence of injury during such procedures. We hypothesized that left vertebral arteries that arise from the aortic arch instead of the subclavian artery might take a more medial path in their ascent making them more susceptible to iatrogenic injury. Fifty human adult cadavers were examined for left vertebral arteries having an aortic arch origin and these were dissected along their entire cervical course. Additionally, two radiological databases of CTA and arteriography procedures were retrospectively examined for cases of aberrant left vertebral artery origin from the aortic arch over a two-year period. Two cadaveric specimens (4%) were found to have a left vertebral artery arising from the aortic arch. The retrospective radiological database analysis identified 13 cases (0.87%) of left vertebral artery origin from the aortic arch. Of all cases, vertebral arteries that arose from the aortic arch were much more likely to not only have a more medial course (especially their preforaminal segment) over the cervical vertebral bodies but also to enter a transverse foramen that was more cranially located than the normal C6 entrance of the vertebral artery. Spine surgeons who approach the anterior cervical spine should be aware that an aortic origin of the left vertebral artery is likely to be closer to the midline and less protected above the C6 vertebral level. Clin. Anat. 30:811-816, 2017. © 2017Wiley Periodicals, Inc.

Unilateral endonasal transcribriform approach with septal transposition for olfactory groove meningioma: can olfaction be preserved?

BACKGROUND: Loss of olfaction has been considered inevitable in endoscopic endonasal resection of olfactory groove meningiomas. Olfaction preservation may be feasible through an endonasal unilateral transcribriform approach, with the option for expansion using septal transposition and contralateral preservation of the olfactory apparatus. METHODS: An expanded unilateral endonasal transcribriform approach with septal transposition was performed in five cadaver heads. The approach was applied in a surgical case of a 24 × 26-mm olfactory groove meningioma originating from the right cribriform plate with partially intact olfaction. RESULTS: The surgical approach offered adequate exposure to the anterior skull base bilaterally. The nasal/septal mucosa was preserved on the contralateral side. Gross total resection of the meningioma was achieved with the successful preservation of the contralateral olfactory apparatus and preoperative olfaction. Six months later, the left nasal cavity showed no disruption of the mucosal lining and the right side was at the appropriate stage of healing for a harvested nasoseptal flap. One year later, the preoperative olfactory function was intact and favorably viewed by the patient. Objective testing of olfaction showed microsomia. CONCLUSIONS: Olfaction preservation may be feasible in the endoscopic endonasal resection of a unilateral olfactory groove meningioma through a unilateral transcribriform approach with septal transposition and preservation of the contralateral olfactory apparatus.

Transposition of the paraclival carotid artery: a novel concept of self-retaining vascular retraction during endoscopic endonasal skull base surgery technical report.

BACKGROUND: Fixed retraction of the internal carotid artery (ICA) has previously been described for use during transcranial microscopic surgery. We report the novel use of a self-retaining microvascular retractor for static repositioning and protection of the ICA during expanded endonasal endoscopic approaches to the paramedian skull base. METHODS: The transmaxillary, transpterygoid approach was performed in five cadaver heads (ten sides). The self-retaining microvascular retractor was used to laterally reposition the pterygopalatine fossa contents during exposure of the pterygoid base/plates and the paraclival ICA to expose the petrous apex. Maximum ICA retraction distance was measured in the x-axis for all ten sides. RESULTS: The average horizontal distance of ICA retraction measured at the mid-paraclival segment for all ten sides was 4.75 mm. In all cases, the carotid artery was repositioned without injury to the vessel or disruption of the surrounding neurovascular structures. CONCLUSIONS: Static repositioning of the ICA and other delicate neurovascular structures was effectively performed during endonasal, endoscopic cadaveric surgery of the skull base and has potential merits in live patients.

Quantifying sulcal and gyral topography in relation to deep seated and ventricular lesions: cadaveric study for basing surgical approaches and review of literature.

OBJECTIVE: Numerical implication of sulcal and gyral topography for surgical approaches has not been studied. METHODS: Percentage gain of distance using sulci as compared to that of gyri was calculated by measuring distances toward the ventricles in 15 hemispheres. RESULTS: Superior frontal sulcus was closest proving greater than 50% gain in distance compared to superior frontal gyrus; inferior temporal sulcus provided greater gain in the temporal lobe. CONCLUSION: Sulci provide upto 58% distance gain. For trans-gyral approaches, MFG and ITG were found closer to the respective ventricular area.

Radio-anatomic measurements and statistical generation of a safe surgical corridor to enter the ventricular trigone while avoiding injury to the optic radiations.

OBJECTIVE: To find a safe operative corridor to the ventricular trigone avoiding injury to the optic radiations (ORs). METHODS: In 24 adult hemispheres, dimensions of the atrium, height of the OR, and the cortex-to-atrium distance were measured. Superior parietal lobule (SPL), parieto-occipital sulcus (POS), and middle temporal gyrus (MTG) traced approaches were used to measure maximum safe angles to enter the atrium without traversing the OR. A statistical algorithm was generated using these measurements to predict the height of the OR and safe angles from measurements from MR imaging of five test hemispheres. Statistically calculated angles were compared with measured angles from dissection. RESULTS: Mean length and height of atrium, height of OR, and cortico-atrium distances were 2.07 cm, 3.36 cm, 2.53 cm, and 4.11 cm, respectively. The height of the atrium influenced the height of the OR significantly (p < 0.0001). The height of the dilated and small atrium was > 4.5 cm (> 95th percentile) and < 2 cm (< 5th percentile), respectively. For the SPL approach, the mean sagittal angle was 15.75 to 41.04 degrees; the mean coronal angle was - 17.08 to 14.92 degrees. For the POS approach, the mean sagittal angle was 51.29 to 70.1 degrees; the mean coronal angle was -8.63 to 17.22 degrees. Mean calculated height (statistically) of the OR was 0.29 mm above the mean observed height (dissection). The calculated angles and observed angles were very similar when tested for a variability of ± 2 degrees. CONCLUSION: The height of the normal atrium was 2.58 cm (height of atrium to height of OR ratio was 1:0.76). An operative corridor to the atrium without damaging the OR can be calculated from MR imaging of the brain.

Low-level amplification of oncogenes correlates inversely with age for patients with nontypical meningiomas.

BACKGROUND: This study sought to identify genes in nontypical meningiomas with gains in copy number (CN) that correlate with earlier age of onset, an indicator of aggressiveness. METHODS: Among 94 adult patients, 91 had 105 meningiomas that were histologically confirmed. World Health Organization grades I (typical), II (atypical), and III (anaplastic) were assigned to tumors in 76, 14, and 1 patient, respectively. Brain invasion indicated that two World Health Organization grade I meningiomas were biologically atypical. DNA from 15 invasive/atypical/anaplastic meningiomas and commercial normal DNA were analyzed with multiplex ligation dependent probe amplification. The CN ratios (fold differences from normal) for 78 genes were determined. The CN ratio was defined as [tumor CN]/[normal CN] for each gene to normalize results. RESULTS: Characteristic gene losses (CN ratio < 0.75) occurred in >50% of the invasive/atypical/anaplastic meningiomas at 22q11, 1p34.2, and 1p22.1 loci. Gains (CN ratio ≥ 2.0) occurred in each tumor for 2 or more of 19 genes. Each of the 19 genes' CN ratio was ≥ 2.0 in multiple tumors, and their collective sums (up to 49.1) correlated inversely with age (r = -0.72), minus an outlier. In patients ≤ 55 versus >55 years, 5 genes (BIRC2, BRAF, MET, NRAS, and PIK3CA) individually exhibited significantly higher CN ratios (P < 0.05) or a trend for them (P < 0.09), with corrections for multiple comparisons, and their sums correlated inversely with age (r = -0.74). CONCLUSIONS: Low levels of amplification for selected oncogenes in invasive/atypical/anaplastic meningiomas were higher in younger adults, with the CN gains potentially underlying biological aggressiveness associated with early tumor development.

Stereotactic placement of ventricular catheters: does it affect proximal malfunction rates?

BACKGROUND: The majority of ventriculoperitoneal (VP) shunt malfunctions are due to proximal catheter failure. Ideal placement of Ommaya reservoirs is desired to avoid toxicity from intraparenchymal chemotherapy infusion. OBJECTIVE: To determine whether stereotactic placement of ventricular catheters decreases the rate of Ommaya reservoir complications and the rate of proximal VP shunt failure. METHODS: Under institutional review board approval, a review of a prospectively collected database was done identifying all patients who underwent stereotactic-guided placement of VP shunts and Ommaya reservoirs performed by a single surgeon between November 2007 and November 2009. Neuronavigation was used to preset a surgical plan consisting of an ideal entry point (usually frontal) and target point (ipsilateral foramen of Monro). The navigation probe was passed along this trajectory. After removal of the navigation probe, pre-sized ventricular catheters were passed without a stylet along the created path. Post-operative CT scans and clinical follow-up were assessed. RESULTS: 70 patients (mean age 44.6 years) underwent 52 VP shunt and 18 Ommaya reservoir placement procedures. Rigid cranial fixation was used in all cases. All catheters were placed in a single pass. Mean operative time was 62 min. Mean follow-up was 16.3 months. No proximal malfunctions or Ommaya complications have been seen thus far. One patient required repositioning of an Ommaya reservoir as post-operative CT showed poor placement (1.4%). One patient with hydrocephalus due to cryptococcal meningitis developed an abdominal abscess and required removal of his entire shunt with subsequent replacement. One patient was noted to have a small amount of intraventricular hemorrhage; this did not result in any clinical change and did not require any further intervention. No other surgical complications were noted. CONCLUSION: In terms of results corroborating decreased proximal malfunction rates, we present the largest series of stereotactic-guided ventricular catheter placements to date. Though time in the operating room is increased due to navigation registration, actual operative time is comparable to procedures without navigation. A longer-term follow-up is needed to assess the longevity of our positive short-term results.

A novel method of identifying the internal acoustic canal in the middle fossa approach in a cadaveric study-the rule of 2s.

Objective Multiple landmarks and anatomic relationships exist to identify internal acoustic canal (IAC) in middle fossa approach for removing intracanalicular schwannomas. We attempted to identify a reproducible, practical method to quickly identify the IAC that would be applicable when an expanded middle fossa approach is required. Design Middle fossa approach was performed on 10 cadavers (21 dissections). In the first head, temporal and suboccipital craniotomies were performed to identify landmarks and formulate a hypothesis. Porous acusticus (PA) was identified and IAC was circumferentially skeletonized into middle fossa. Orientation of IAC in the middle fossa was evaluated in relation to foramen spinosum (FS), foramen ovale (FO), petrous ridge, and petrous apex. Consistency of this relationship was tested in the remaining heads. Results The opening of PA (point A) was consistently found at a mean of 2.38 cm posterolateral to the petrous apex along the petrous ridge (range 2.1 to 2.8). A line was drawn from the FO to FS and extrapolated posteriorly. The IAC (point B) was found a mean distance of 2.39 cm from FS along the FS-FO line (range 2.1 to 2.8). The course of IAC was consistently found by connecting point A to point B. Conclusion A novel, practical, and reproducible method is described to identify the IAC via the expanded middle fossa approach.

Fusiform aneurysms of the anterior communicating artery: illustrative series of 5 cases with operative techniques.

BACKGROUND: Fusiform anterior communicating artery (ACoA) aneurysms (ACoAAs) are rare, and a series of these aneurysms has not been reported. Large fusiform ACoAA are easily identifiable, whereas smaller ones can coexist with a saccular component. OBJECTIVE: To provide a clear-cut definition, report the incidence of these aneurysms, present a series with follow-up data, and discuss operative nuances and clip application techniques. METHODS: Review of a single-surgeon operative series of all ACoAAs to identify fusiform types. When A1 or A2 vessels entered or arose from the ACoAA, it was classified as fusiform. Follow-up imaging and clinical progress were noted. RESULTS: Five fusiform ACoAAs were identified. Patient age ranged from 19 to 68 years. Anatomy varied from very obvious large fusiform, to identifiable fusiform nature with a saccular component, to an irregularly shaped aneurysm with a fusiform element of the ACoA. A large fusiform aneurysm reconstructed in 1 patient recurred 11 years later as a ruptured fusiform ACoAA that was reconstructed again. One patient had a giant thrombosed aneurysm with thrombosed vessels in which A2 reconstruction was attempted with sacrifice of the ACoA. In others, simple clipping achieved obliteration of the aneurysm together with creating a normal dimension ACoA. There were no operative deaths; other than rupture intraoperatively, no other complications occurred. Postoperatively, no patient had new neurological deficits, 3 had short-term memory loss, and all were ambulatory with good speech function. CONCLUSION: Review of angiograms and 3-dimensional computed tomography angiography reconstruction images can identify the complex and fusiform entity of ACoAA, which is important for preoperative planning. Experience in operative techniques and thorough knowledge of the ACoA anatomy are cornerstones to obliterate the aneurysm, maintain flow in all vessels, and surgically create an ACoA of normal caliber.

Microsurgical excision of colloid cyst with favorable cognitive outcomes and short operative time and hospital stay: operative techniques and analyses of outcomes with review of previous studies.

OBJECTIVE: Microsurgical and endoscopic colloid cyst excision differ with regard to operative time, length of hospital stay, and extent of resection. METHODS: A retrospective review of a single surgeon's microsurgical colloid cyst resection in 10 consecutive patients was performed. Cyst size, hydrocephalus, symptoms, operative time, postoperative stay, complications, and objective testing of memory, concentration, calculation, and attention (cognition), along with performance at job, were noted. RESULTS: All 10 patients had complete excision. Mean cyst size, mean operative time, and median postoperative stay were 1.6 cm, 124 minutes, and 3.5 days respectively. The mean operative time from cyst visualization to complete excision was 18 minutes. Follow-up ranged from 6 to 111 months (mean, 49.5 months). There were no recurrences; symptoms (headache, visual and balance problems) improved significantly in 70%. Postoperative cognitive performance, including memory, was the same in 8 patients (5 of whom had preoperative memory problems) and worse in 2 patients who had no preoperative memory problems. The bone flap was removed in 1 patient for wound dehiscence. Hemiparesis in another patient, seen immediately after surgery, completely resolved before discharge. One patient with loculated ventricles and multiple previous shunt revisions had unresolved hydrocephalus after cyst excision. CONCLUSION: We report the very short operative times and postoperative stay for microsurgery, which are comparable to some endoscopic series. We also report results of objective tests of cognitive performance. With adoption of a callosal incision of 1 cm or less, meticulous dissection around the fornix, and complete excision, acceptable long-term cognitive function and functional performance were achieved. Our results support the microsurgical approach. A larger sample size can more conclusively establish whether it should be chosen over the endoscopic technique.

Laparoscopic nephrectomy in a patient with ankylosing spondylitis: surgical and anesthetic challenges.

A 55-year-old man with ankylosing spondylitis was referred with left sided loin pain, loin mass, and painless macroscopic hematuria. Physical examination revealed a palpable loin mass, fixed flexion deformity of the lumbar and cervical spines, with severely restricted cervical movement and mouth opening. An ultrasound and computed tomography scan confirmed a 7-cm solid mass in the left kidney. Following a multidisciplinary meeting he elected to undergo radical laparoscopic nephrectomy. An anesthetic opinion was sought in view of the expected difficulties with intubation. Mouth opening was restricted to 3 fingers and he was Mallampati grade 3 on airway examination. As the degree of spinal flexion deformity and restricted spinal movement was significant, the patient was placed in a lateral decubitus position, and surgery was performed using a transperitoneal approach. A five-port technique was employed and was carried out successfully with no complication. Operative time was 240 minutes and estimated blood loss was 700 mL. His postoperative inpatient stay was 4.5 days. Surgical margins were clear and the patient was disease-free at 2-year follow-up. Laparoscopic nephrectomy in a patient with ankylosing spondylitis is technically challenging for both the surgeon and the anesthetist, however, with the right preoperative planning, potential morbidity can be limited to ensure a good outcome for the patient.