A new simple and free tubular device for microscopic transcortical approach to deep-seated lesions: technical note and case example.

BACKGROUND: Surgery for deep-seated brain tumors remains challenging. Transcortical approaches often require brain retraction to ensure an adequate surgical corridor, thus possibly leading to brain damage. Various techniques have been developed to minimize brain retraction such as self-retaining retractors, endoscopic approaches, or tubular retractor systems. Even if they evenly distribute the mechanical pressure over the parenchyma, rigid retractors can also cause some degree of brain damage and have significant disadvantages. We propose here a soft cottonoid retractor for microscopic resection of deep-seated and ventricular lesions. METHODS: Through a small corticectomy, a channel route with a blunt cannula is developed until the lesion is reached. Then, a "balloon-like system" made with a surgical glove is progressively inflated, dilatating the surgical corridor. A mini-tubular device, handmade by suturing a surgical cottonoid, is positioned into the corridor, unfolded, and sutured to the edge of the dura, to prevent it from being progressively expelled from the working channel. This allows a good visualization of the lesion and surrounding structures under the microscope. RESULTS: Advantages of this technique are the softness of the tube walls, the absence of rigid arm to hold the tube, and the possibility for the tube to follow the movements of the instruments and to modify its orientation according to the working area. CONCLUSION: This simple and inexpensive tubular working channel for microscopic transcortical approach is a valuable alternative technique to traditional self-retaining retractor and rigid tube for the microsurgical resection of deep-seated brain tumors.

Cognitive versus virtual reality simulation for evaluation of technical skills in neurosurgery.

OBJECTIVE: Simulation is gaining momentum as a new modality of medical training, particularly in acute care settings such as surgery. In the present study, the authors aimed to compare individual cognitive skills with manual abilities as assessed by virtual reality (VR) simulation among neurosurgical residents. METHODS: Participants were asked to complete a multiple-choice questionnaire assessing their surgical abilities regarding three basic neurosurgical procedures (endoscopic third ventriculostomy, cranial meningioma, and lumbar laminectomy). They subsequently performed these same three procedures on a VR simulator (NeuroTouch). RESULTS: The authors found that cognitive scores correlated with self-evaluation of surgical experience and autonomy. On the contrary, VR simulation, as assessed by NeuroTouch automated scoring, did not reflect participants' cognitive or self-evaluation of their surgical proficiency. CONCLUSIONS: The results of this study suggest that neurosurgical education should focus as much on cognitive simulation (e.g., careful planning and critical appraisal of actual procedures) as on VR training of visuomotor skills.

Hybrid antero-lateral transcondylar approach to the clivus: a laboratory investigation and case illustration.

BACKGROUND: Surgical treatment of lesions involving the ventral craniovertebral junction (CVJ) and the lower clivus, traditionally involved complex lateral or transoral approaches to the skull base. However, mid or upper clivus involvement requires more extensive lateral approaches. Recently, the endoscopic endonasal approach (EEA) has become the standard for upper CVJ lesions and medial clival, and a valuable alternative for those tumors extending in its upper third as well as laterally. However, the EEA is associated with an increased risk of post-operative CSF leakage and infection when the tumor is characterized by an intradural extension. Furthermore, whenever the tumor has significant lateral and/or inferior extension below the odontoid process, the chances for a complete resection decrease. METHOD: To analyze the extent of exposure of a hybrid microscopic-endoscopic transcondylar antero-lateral approach to the CVJ and clival region, and to verify its effectiveness in terms of mid and upper clival access. Five silicone-injected cadaver heads were used. Following a standard antero-lateral approach, condylectomy and jugular tubercle drilling were performed, after which angled endoscopes were utilized to extend the bone resection to the clivus. A volumetric assessment of the amount of clival removal was carried out. A case of CVJ chordoma operated through this approach is presented. RESULTS: The hybrid antero-lateral transcondylar approach provides adequate exposure of the ventral CVJ, up to the dorsum sellae and the sphenoid sinus, the contralateral petrous apex, and the contralateral paraclival internal carotid artery (ICA). Approximately 60% of the total clival volume can be removed with this approach. The main limitation is the limited visualization of the ipsilateral paraclival ICA and petrous apex. CONCLUSION: The hybrid antero-lateral transcondylar approach is a valuable surgical option for CVJ tumor extending from C2 to the mid and upper clivus.

Adhesive arachnoiditis, subarachnoid hemorrhage, and intradural extramedullary thoracic cavernoma: illustrative case.

BACKGROUND: Spinal arachnoiditis can result from various factors, including spinal subarachnoid hemorrhage (sSAH). In this paper, the authors describe a case of intradural extramedullary cavernoma with an initial presentation of subarachnoid hemorrhage leading to multilevel spinal arachnoiditis to discuss the pathophysiology and optimal treatment strategy. OBSERVATIONS: Spinal intradural extramedullary cavernoma manifesting with sSAH is a rare clinical presentation; therefore, there is no clear strategy for the management of sSAH. Spinal arachnoiditis is a result of chronic inflammation of the pia arachnoid layer due to hematomyelia. No effective treatment that interrupts this inflammatory cascade and would also prevent the development of spinal arachnoiditis has been described to date. LESSONS: Lumbar drainage could aid in sSAH management, relieve spinal cord compression, and restore the normal spinal cerebrospinal fluid circulation gradient. It could help to clear the blood degradation products rapidly and prevent early inflammatory arachnoiditis development. Mini-invasive intrathecal endoscopic adhesiolysis appears to be a reasonable approach for reducing the risk of aggravating spinal arachnoiditis with a mechanical-surgical stimulus. Whether a conservative approach should be applied in these patients with mild myelopathy symptoms is still debatable.

C2 Odontoid Fracture Associated with C1-C2 Rotatory Dislocation: A Retrospective Analysis of 2 Surgical Techniques.

BACKGROUND: Odontoid fractures in association with a C1-C2 rotatory luxation reports are seldom found in the literature. The fusion between the lateral mass of C1 and C2 could be of interest to ensure adequate treatment in these particular cases. We report 23 cases where there was coexistence of an odontoid fracture and rotatory subluxation, which were treated surgically using cages between C1 and C2 or just traditional Goel-Harms technique. We evaluated the radiologic fusion rate, reoperation rate, and complications. METHODS: This was a single-center, retrospective, cohort study of patients with C2 fractures (mixed type and C1-C2 rotatory luxation according to the Fielding classification) who were treated surgically. Radiologic computed tomography scans were used to assess fusion (presence of bridging trabecular bone end plate or pseudoarthrosis) between 6 months and 1.5 years after the surgery. RESULTS: Twenty-three patients were diagnosed with C2 fractures and C1-C2 rotatory luxation that were treated surgically and were suitable for the analysis; 11 patients underwent C1-C2 fusion with intra-articular cages, and 12 underwent a classical Goel-Harms technique. The fusion rate at the C1-C2 joint was higher in the cages group. Only 12 patients exhibited fusion at the level of the odontoid fracture. CONCLUSIONS: C2 fractures associated with C1-C2 rotatory dislocation are rare. The fusion rate at the level of the odontoid in these patients appears to be lower than that reported in patients without rotatory dislocation. It may be of special interest to obtain a clear fusion at the C1-C2 joint, where this type of implant seems to offer an advantage.

Functional Outcome After Spinal Meningioma Surgery. A Nationwide Population-Based Study.

OBJECTIVE: To describe and analysed the functional outcome (FO) after spinal meningioma (SM) surgery. METHODS: We processed the système national des données de santé (SNDS) i.e. , the French national administrative medical database to retrieve appropriate cases. We analysed the International Classification of Diseases 10 codes to assess the FO. Logistic models were implemented to search for variables associated with a favourable FO i.e. , a patient being independent at home without disabling symptom. RESULTS: A total of 2,844 patients were identified of which 79.1% were female. Median age at surgery was 66 years, interquartile range (IQR) (56-75). Ninety-five point nine percent of the SMs were removed through a posterior ± lateral approach and 0.7% need an associated stabilisation. Benign meningioma represented 92.9% and malignant 2.1%. Median follow-up was 5.5 years, IQR (2.1-8), and at data collection 9% had died. The FO was good and increased along the follow-up: 84.3% of the patients were alive and had not associated symptoms at one year, 85.9% at 2 and 86.8% at 3 years. Nonetheless, 3 years after the surgery 9.8% of the alive patients still presented at least one disabling symptom of which 2.7% motor deficit, 3.3% bladder control problem, and 2.5% gait disturbance. One point seven percent were care-provider dependent and 2.1% chair or bedfast. In the multivariable logistic regression an older age at surgery (odds ratio [OR], 0.37; 95% confidence interval [CI], 0.29-0.47, p < 0.001), a high level of comorbidities (OR, 0.71; 95% CI, 0.66-0.75, p < 0.001), and an aggressive tumor (OR, 0.49; 95% CI, 0.33-0.73; p < 0.001) were associated with a worse FO. CONCLUSION: FO after meningioma surgery is favourable but, may be impaired for older patients with a high level of comorbidities and aggressive tumor.

The Rostral Mucosa: The Door to Open and Close for Targeted Endoscopic Endonasal Approaches to the Clivus.

BACKGROUND: Extended endoscopic endonasal approaches (EEAs) have progressively widened the armamentarium of skull base surgeons. In order to reduce approach-related morbidity of EEAs and closure techniques, the development of alternative strategies that minimize the resection of normal tissue and alleviate the use of naso-septal flap (NSF) is needed. We report on a novel targeted approach to the clivus, with incision and closure of the mucosa of the rostrum, as the initial and final step of the approach. OBJECTIVE: To present an alternative minimally invasive approach and reconstruction technique for selected clival chordomas. METHODS: Three cases of clival chordomas illustrating this technique are provided, together with an operative video. RESULTS: The mucosa of the rostrum is incised and elevated from the underlying bone, as first step of surgery. Following tumor resection with angled scope and instruments, the mucosa of the sphenoid sinus (SS) is removed and the tumor cavity and SS are filled with abdominal fat. The mucosal incision of the rostrum is then sutured. A hangman knot is prepared outside the nasal cavity and tightened after the first stitch and a running suture is performed. CONCLUSION: We propose, in this preliminary report, a new targeted approach and reconstruction strategy, applying to EEAs the classic concept of skin incision and closure for transcranial approaches. With further development in the instrumentations and visualization tools, this technique may become a valuable minimally invasive endonasal approach for selected lesions.

Endoscope-assisted far-lateral transcondylar approach for craniocervical junction chordomas: a retrospective case series and cadaveric dissection.

OBJECTIVE: Craniocervical junction (CCJ) chordomas are a neurosurgical challenge because of their deep localization, lateral extension, bone destruction, and tight relationship with the vertebral artery and lower cranial nerves. In this study, the authors present their surgical experience with the endoscope-assisted far-lateral transcondylar approach (EA-FLTA) for the treatment of CCJ chordomas, highlighting the advantages of this corridor and the integration of the endoscope to reach the anterior aspect and contralateral side of the CCJ and the possibility of performing occipitocervical fusion (OCF) during the same stage of surgery. METHODS: Nine consecutive cases of CCJ chordomas treated with the EA-FLTA between 2013 and 2020 were retrospectively reviewed. Preoperative characteristics, surgical technique, postoperative results, and clinical outcome were analyzed. A cadaveric dissection was also performed to clarify the anatomical landmarks. RESULTS: The male/female ratio was 1.25, and the median age was 36 years (range 14-53 years). In 6 patients (66.7%), the lesion showed a bilateral extension, and 7 patients (77.8%) had an intradural extension. The vertebral artery was encased in 5 patients. Gross-total resection was achieved in 5 patients (55.6%), near-total resection in 3 (33.3%), and subtotal resection 1 (11.1%). In 5 cases, the OCF was performed in the same stage after tumor removal. Neither approach-related complications nor complications related to tumor resection occurred. During follow-up (median 18 months, range 5-48 months), 1 patient, who had already undergone treatment and radiotherapy at another institution and had an aggressive tumor (Ki-67 index of 20%), showed tumor recurrence at 12 months. CONCLUSIONS: The EA-FLTA provides a safe and effective corridor to resect extensive and complex CCJ chordomas, allowing the surgeon to reach the anterior, lateral, and posterior portions of the tumor, and to treat CCJ instability in a single stage.

Delayed Instrumentation Following Removal of Cranio-Vertebral Junction Chordomas: A Technical Note.

Objective To investigate on the feasibility and safety of a new approach which consists of delaying instrumentation after destabilizing craniovertebral junction (CVJ) chordoma surgery, allowing proton beam radiotherapy to be performed in a metal-free tumoral cavity. Design This is a retrospective series of a prospectively maintained database. Participants Five consecutive patients operated on for a CVJ chordomas for which instrumentation after tumor resection was deferred to after radiotherapy treatment. Main Outcome Measures The main outcome consisted of measurements of the following parameters: C0-C2 angle, atlanto-dens interval (ADI), condylar gap, and the position of the dens relative to McGregor's line and coronal inclination, performed at 3 different times for all patients: before tumor surgery (baseline), before instrumentation surgery, and after instrumentation surgery. Results For all patients, CVJ parameters deteriorated during the delay period, but stayed within normal limits for most. Because of radiological instability, one patient necessitated instrumentation before receiving radiotherapy. All parameters except condylar gap were partially corrected after instrumentation. No new neurological symptom or evolving neck pain occurred during the delay period. Conclusion Delayed instrumentation of CVJ chordomas can be a safe alternative that might lead to improved subsequent radiotherapeutical treatment. Patient's selection and close clinical and radiological follow-up are mandatory for the success of this approach.

Decompensation of a Thoracic Meningioma Below the Operated Level: A Dramatic and Unexpected Complication.

BACKGROUND: Paraplegia after lumbar spinal surgery has been previously described. It was generally provoked by a missed thoracic compression because of degenerative processes, arachnoid cyst, and spinal cord tumor such as meningioma. We describe here a case of a patient with neurofibromatosis type 2 (NF-2) with multiple spinal meningiomas that developed postoperative paraplegia because of decompensation of spinal cord compression below and far from the operated level. CASE DESCRIPTION: A 54-year-old woman with NF-2 was followed-up for multiple spinal meningiomas (C7-T1, T6-7, T9-10 levels). Surgery for the symptomatic and larger lesion (C7-T1) was scheduled. Postoperatively, the patient was found to have paraplegia with sensor anesthesia below the level of the T6 vertebra. An urgent spinal magnetic resonance imaging (MRI) scan was performed revealing the absence of complication at the operated level (C7-T1) but the appearance of a marked intramedullary hyperintensity at the T6-7 level. An urgent T6-7 laminectomy and removal of the meningioma was performed. The postoperative phase was marked by a poor recuperation. Spinal MRI scan at 3 months clearly showed a severely injured spinal cord at the T6-7 level consistent with the neurologic status of the patient. CONCLUSIONS: We report here the first case of acute neurologic deterioration after decompensation of a spinal cord compression below the operated level in spinal intradural surgery. Neurosurgeons must be aware of this possible complication when treating patients with multiple spinal meningiomas.

Oculomotor Neurofibroma: A Different Histology Implying an Unsatisfying Clinical Outcome.

BACKGROUND: Tumors arising from oculomotor nerve are rare, with few cases reported in the literature. Generally, whereas schwannomas are well encapsulated tumors, neurofibromas tend to invade the entire nerve fibers. These differences influence surgical resection and neurological clinical outcome, with neurofibroma often requiring the sacrifice of the nerve. Accordingly, an incorrect preoperative diagnosis can lead to incomplete patient counseling before surgery. CASE DESCRIPTION: We report 2 cases: a patient with oculomotor schwannoma and a patient with oculomotor neurofibroma. After tumor resection, the patient with a diagnosis of schwannoma recovered with 3rd nerve palsy, while patient with the neurofibroma developed a complete oculomotor nerve deficit. For each patient, surgical strategy and neurological outcome are elucidated in relation with differences in preoperative magnetic resonance imaging and histology. CONCLUSIONS: To the best of our knowledge, this is the first report of an oculomotor neurofibroma. When an oculomotor nerve tumor is suspected, a careful preoperative evaluation of magnetic resonance imaging guides in distinguishing the different histology, in selecting the treatment strategy, and in correctly informing the patient on expected postoperative neurologic outcome.

From the Occipital Condyle to the Sphenoid Sinus: Extradural Extension of the Far Lateral Transcondylar Approach with Endoscopic Assistance.

BACKGROUND: Surgical management of extensive skull base tumors, such as chordoma and chondrosarcoma, remains very challenging. The need for gross total removal to improve survival must be weighed against the risk of injury to neurovascular structures and the loss of stability at the craniovertebral junction. In cases of tumors that are already compromising craniovertebral junction stability, the occipital condyle can be exploited as a deep keyhole to reach the clivus, petrous apex, and sphenoid sinus. METHODS: We performed an anatomic study on 7 cadaveric specimens to describe the main landmarks and boundaries of the corridor. We also provide a clinical case to demonstrate the feasibility of the approach. RESULTS: In all specimens, using the space provided by the condyle, it was possible to drill the petrous bone up to the posterior wall of the sphenoid sinus following the direction of the inferior petrosal sinus. To successfully complete the approach, after the hypoglossal canal was exposed, endoscopic assistance was needed to overcome the narrowing of the visual field provided by the microscope. CONCLUSIONS: In cases of invasive skull base tumor involving the craniovertebral junction and affecting its stability, the occipital condyle can be exploited as a deep keyhole to the homolateral and contralateral petrous apex, clivus, and sphenoid sinus.

The orbitopterygoid corridor as a deep keyhole for endoscopic access to the paranasal sinuses and clivus.

OBJECTIVE: The anteromedial triangle (AMT) is the triangle formed by the ophthalmic (V1) and maxillary (V2) nerves. Opening of this bony space offers a limited access to the sphenoid sinus (SphS). This study aims to demonstrate the utility of the orbitopterygopalatine corridor (OPC), obtained by enlarging the AMT and transposing the contents of the pterygopalatine fossa (PPF) and V2, as an entrance to the SphS, maxillary sinus (MaxS), and nasal cavity. METHODS: Five formalin-injected cadaveric specimens were used for this study (10 approaches). A classic pterional approach was performed. An OPC was created through the inferior orbital fissure, between the orbit and the PPF, by transposing the PPF inferiorly. The extent of the OPC was measured using neuronavigation and manual measurements. Two illustrative cases using the OPC to access skull base tumors are presented in the body of the article. RESULTS: Via the OPC, the SphS, MaxS, ethmoid sinus (EthS), and nasal cavity could be accessed. The use of endoscopic assistance through the OPC achieved better visualization of the EthS, SphS, MaxS, clivus, and nasal cavity. A significant gain in the area of exposure could be achieved using the OPC compared to the AMT (22.4 mm2 vs 504.1 mm2). CONCLUSIONS: Opening of the AMT and transposition of V2 and the contents of the PPF creates the OPC, a potentially useful deep keyhole to access the paranasal sinuses and clival region through a middle fossa approach. It is a valuable alternative approach to reach deep-seated skull base lesions infiltrating the cavernous sinus and middle cranial fossa and extending into the paranasal sinus.

Cerebrospinal Fluid Fistula in the Frontal Sinus Secondary to Obstructive Hydrocephalus.

In some rare cases, long-standing hydrocephalus can cause "high-pressure" cerebrospinal fluid fistulas. We report the case of a young overweight woman with rhinorrhea secondary to hydrocephalus with a fistula into the frontal sinus. Brain imaging studies revealed aqueduct stenosis. Ventriculocisternostomy treated the hydrocephalus but did not cure the rhinorrhea, and additional multilayer surgical skull base repair was necessary. In these cases, the CSF leakage acts as a safety valve, and closure will worsen the patient's condition if the causative lesion has not been treated first. Moreover, identifying the exact location of the fistula can be challenging and will usually require high-resolution bone computed tomography.