Giancarlo D'Andrea

Cyst of the medullary conus: malformative persistence of terminal ventricle or compressive dilatation?

Abstract. The ventriculus terminalis is a cavity situated at the level of the conus medullaris, enclosed by ependymal tissue and normally present as a virtual cavity or as a mere ependymal residue. In rare cases, and almost exclusively in pediatric age, the ventriculus terminalis may be visualized by radiological investigations, either by sonography or MRI, and represents a transient finding in children under 5 years of age. In pathological conditions, a cyst of the conus medullaris is probably the result of a persistent ventriculus terminalis and is usually described in children in association with a tethered cord; in a very limited number of cases, it has been described in adults whose clinical symptoms consist of neurological and/or sphincter disturbances not associated with other pathologies. The authors describe the case of a 42-year-old female with a cyst of the conus whose only symptom was imperious minction; she had been suffering from these urinary disorders for many years. The patient was not operated on because the clinical situation remained stable, without modifications of the MRI in follow-up over a 6-year period. The authors therefore suggest that in adult patients, a cyst of the conus medullaris is probably an expression of malformative persistence of the fifth ventricle and does not necessarily have a progressive evolution.

Pre- and intraoperative tractographic evaluation of corticospinal tract shift

BACKGROUND:Magnetic resonance with diffusion tensor image (DTI) may be able to estimate trajectories compatible with subcortical tracts close to brain lesions. A limit of DTI is brain shifting (movement of the brain after dural opening and tumor resection). OBJECTIVE:To calculate the brain shift of trajectories compatible with the corticospinal tract (CST) in patients undergoing glioma resection and predict the shift directions of CST. METHODS:DTI was acquired in 20 patients and carried out through 12 noncollinear directions. Dedicated software “merged” all sequences acquired with tractographic processing and the whole dataset was sent to the neuronavigation system. Preoperative, after dural opening (in 11) and tumor resection (in all) DTI acquisitions were performed to evaluate CST shifting. The extent of shifting was considered as the maximum distance between the preoperative and intraoperative contours of the trajectories. RESULTS:An outward shift of CST was observed in 8 patients and an inward shift in 10 patients during surgery. In the remaining 2 patients, no intraoperative displacement was detected. Only peritumoral edema showed a statistically significant correlation with the amount of shift. In those patients in which DTI was acquired after dural opening as well (11 patients), an outward shifting of CST was evident in that phase. CONCLUSION:The use of intraoperative DTI demonstrated brain shifting of the CST. DTI evaluation of white matter tracts can be used during surgical procedures only if updated with intraoperative acquisitions.

Dorsal foramenal extraosseous epidural cavernous hemangioma.

Cavernous hemangiomas are vascular hamartomatous malformations that affect the central nervous system. This pathology is frequently encountered in the cerebral hemispheres, cerebellum, and brainstem. Cavernous hemangiomas infrequently occur at the spinal level or relative to an intramedullary localization; extramedullary epidural sites are also sometimes affected by this pathology. We report an extradural, extramedullary, cavernous hemangioma with foramenal extension of the dorsal section and discuss the differential diagnosis with dorsal foramenal neurinoma. A 52-year-old woman was admitted with irritation and deficit symptoms radiating into the left D3 spinal root space. The first radiological diagnosis was of a foramenal neurinoma beginning at the D3 root. The presence of a heterogeneous MR signal in both T1 and T2 images led us to consider the differential diagnosis of a cavernous hemangioma lesion. The patient underwent microsurgical treatment with a far lateral extraforamenal approach. Symptoms quickly improved: pain and dysesthesia disappeared after surgery and only light hypoesthesia was found. We want to stress the importance of MR imaging in formulating a correct differential diagnosis with foramenal neurinoma and underline that microsurgical treatment with a far lateral extraforamenal approach allowed us to remove the lesion completely without affecting Deniss posterior column, the lamina, and the articular facet.

Single cerebral metastasis from colorectal adenocarcinoma

Single cases are described in 50% of reported intracranial metastases. Single cerebral metastasis from colorectal adenocarcinoma is not very common, with a frequency varying between 0.5% and 1%. In our institute between 1960 and 2000, 44 patients affected by single metastasis from colorectal carcinoma were surgically treated. Surgical treatment with postoperative radiant therapy is necessary. These patients show improved quality of life, above all in relation to the maintenance of functional autonomy during the survival period.

Spinal en plaque meningiomas: a contemporary experience.

OBJECTIVE:Spinal en plaque meningiomas are rare and challenging lesions because of their tendency to induce spinal arachnoiditis. The surgical treatment of this type of meningioma is more complex than that of classic meningioma. METHODS:We report seven cases of spinal en plaque meningiomas and review all the cases reported in the literature accessible to us by a MEDLINE search. RESULTS:All patients underwent microsurgery. Complete tumor removal was achieved in three patients. Subtotal removal was performed in four patients. A permanent neurological worsening was observed in one patient. CONCLUSION:Spinal meningiomas en plaque bear a prognosis poorer than that of classic meningiomas with regard to the possibility of a definitive surgical cure because recurrence or postoperative arachnoiditis occurs frequently. Total surgical removal should be attempted only when a clear plane of cleavage between tumor and arachnoid exists.

Platinum-iridium subdermal magnetic resonance imaging-compatible needle electrodes are suitable for intraoperative neurophysiological monitoring during image-guided surgery with high-field intraoperative magnetic resonance imaging: An experimental study

BACKGROUND: Neurosurgery aims to achieve maximal tumor resection while preserving neurological function. Tools such as neuronavigation, high-field intraoperative magnetic resonance imaging (iMRI), and intraoperative neurophysiological monitoring (IOM) have consistently helped to achieve this goal, but integration has often been difficult. Surgery of eloquent areas requires IOM, which in an operating theater equipped with high-field (1.5-T) iMRI could present several issues. OBJECTIVE: To identify the electrodes types more suitable for IOM in a high-field iMRI operating theater by performing an experimental study on phantoms, to report our experience with platinum-iridium (Pt/Ir) electrodes during surgery, and to prove that integration between IOM with Pt/Ir electrodes and high-field iMRI is safe and reliable. METHODS: Electrodes of different materials (gold, Pt/Ir, and stainless steel) were tested on jelly phantom and apples to evaluate their safety and compatibility. Subsequently, electrodes were tested on 5 healthy volunteers before being used on patients. RESULTS: None of the different electrodes presented thermal instability, and no damage to the volunteers’ skin occurred. Stainless steel electrodes caused severe imaging distortion. Gold electrodes had no distortion, but their high cost makes their use in routine surgery unaffordable. Pt/Ir electrodes are significantly less expensive than gold electrodes and were completely safe, compatible, and suitable for use in an operating theater with high-field iMRI, providing excellent IOM and mild interference that did not affect the quality of intraoperative imaging. CONCLUSION: We suggest the use of Pt/Ir electrodes for IOM in 1.5-T iMRI suites. ABBREVIATIONS: DTI, diffusion tensor imaging iMRI, intraoperative magnetic resonance imaging IOM, intraoperative neurophysiological monitoring

The Value of Neurosurgical and Intraoperative Magnetic Resonance Imaging and Diffusion Tensor Imaging Tractography in Clinically Integrated Neuroanatomy Modules: A Cross-Sectional Study.

Neuroanatomy is considered to be one of the most difficult anatomical subjects for students. To provide motivation and improve learning outcomes in this area, clinical cases and neurosurgical images from diffusion tensor imaging (DTI) tractographies produced using an intraoperative magnetic resonance imaging apparatus (MRI/DTI) were presented and discussed during integrated second‐year neuroanatomy, neuroradiology, and neurosurgery lectures over the 2008–2011 period. Anonymous questionnaires, evaluated according to the Likert scale, demonstrated that students appreciated this teaching procedure. Academic performance (examination grades for neuroanatomy) of the students who attended all integrated lectures of neuroanatomy, was slightly though significantly higher compared to that of students who attended these lectures only occasionally or not at all (P=0.04). Significantly better results were obtained during the national progress test (focusing on morphology) by students who attended the MRI/DTI‐assisted lectures, compared to those who did so only in part or not at all, compared to the average student participating in the national test. These results were obtained by students attending the second, third and, in particular, the fourth year (P≤0.0001) courses during the three academic years mentioned earlier. This integrated neuroanatomy model can positively direct students in the direction of their future professional careers without any extra expense to the university. In conclusion, interactive learning tools, such as lectures integrated with intraoperative MRI/DTI images, motivate students to study and enhance their neuroanatomy education. Anat Sci Educ 6: 294–306.

Chondromyxoid Fibroma of the Skull Base: Our Experience with an Elusive Disease

Abstract Chondromyxoid fibroma (CMF) is an extremely rare lesion of the skull base. This histologic type typically predilects metaphysis of the long bones. It is locally invasive/infiltrative, and this tendency is more concerning in the skull base, where a radical resection is often technically impossible because of the presence of vital neurovascular structures. We present a case of a 19‐year‐old woman who presented with a sudden onset of right facial weakness, progressively worsening to a severe disfiguring motor weakness. Gadolinium‐enhanced brain magnetic resonance imaging showed an osteolytic lesion located in the right mastoid involving the stylomastoid foramen and the right seventh cranial nerve. A partial mastoidectomy was performed, with an excellent rate of tumor resection and complete local control of the disease at follow‐up. The analysis of current literature indicates that a radiologic diagnosis is rarely strictly convincing of CMF. Histologic diagnosis is often difficult due to the lack of a specific immunohistochemical pattern of chondrosarcoma. Surgery is currently recognized as the mainstay to manage this lesion, although a trend toward adjuvant radiation therapy (RT) currently is seen. Although a tendency of local recurrence is well recognized in the literature, the very slow and indolent behavior of this lesion plus the trend to enhance local control of the disease with high‐dose RT pushed us to a reappraise the role of radical skull base surgeries burdened by the risks of major complications, cosmetic deformities, and additional neurologic deficits.

Preoperative Volumetric Assessment Matched with High-Field Intraoperative Magnetic Resonance Imaging-Guided Stereotactic Evacuation of Brain Abscesses

OBJECTIVE AND BACKGROUND Stereotactic evacuation is currently accepted as a minimally invasive surgical procedure for the management of brain abscesses. Intraoperative magnetic resonance imaging (Io-MRI) is well established in neuro-oncology but its role has not been completely outlined for brain abscess surgery. The objective of this work is to analyze radiologic, clinical, and laboratory results in a cohort of patients with brain abscesses treated with an original protocol in which the minimally invasiveness of a stereotactic technique is matched with preoperative volumetric evaluation and Io-MRI. METHODS For each of the 12 patients included in this cohort, the following data were recorded: age, sex, location, presentation, grade of evacuation, duration of follow-up, mean preoperative and postoperative Glasgow Outcome Scale score, functional outcome, number of abscess loculations, number of Io-MRI, duration of antibiotic therapy, preoperative and postoperative laboratory findings, pathogen strains and possible recurrences. RESULTS The operative time was in 10/12 patients under 90 minutes. A total of 8/12 patients needed no more than 30 days of antibiotics; 9/12 patients had minor or no sequelae and returned to normal activities; only 1 recurrence of brain abscess was recorded in the sample. Only 1 death was recorded in the sample. CONCLUSIONS Although this work is intended to present preliminary results of an original protocol for the management of brain abscess, the role of a precise preoperative volumetric evaluation matched with Io-MRI in the treatment of this disease seems of great benefit, as in surgical neuro-oncology.

Risk of Postoperative Performance Status Worsening after Resection of Lesions Involving the Motor Pathway: A Multinomial Logistic Regression Model

Background and Study Objective In surgery for gliomas and brain metastases, preservation of neurologic functions is essential to ensure a good quality of life and the eligibility for adjuvant therapies. This article assesses which factors could influence the functional outcome in patients with lesions located in the motor pathways. Materials and Methods A total of 92 patients with gliomas and metastases involving the motor pathways were studied for concerns regarding quality of life (Karnofsky performance status [KPS] and modified Rankin scale [mRS]) before and after surgical treatment supported by intraoperative neuromonitoring. Patient‐related, surgery‐related, and lesion‐related data were recorded to identify the relationships with postoperative performance status. The relationship between lesions and the corticospinal tract were investigated with preoperative magnetic resonance imaging sequences and tractographic reconstructions. Results Means of preoperative mRS and KPS were 1.91 ± 1.34 and 80.8 ± 20, and at 30 days postoperatively they were 1.93 ± 1.63 and 79.8 ± 24.4, respectively. The better preoperative performance status was a predictor of better outcome in terms of quality of life. Gender showed a statistical association with &Dgr;KPS (p = 0.033) and &Dgr;mRS (p = 0.031). A recurrent lesion was a predictor of poor functional outcome (p = 0.045 for KPS at 30 days).A left‐sided lesion showed a statistical association with a lesser improvement with respect to right sided. Complications were associated with a lesser functional improvement (&Dgr;mRS, &Dgr;KPS, and clinical improvement: p = 0.001, p = 0.006, and p = 0.003, respectively). Hemorrhagic complications were associated with the worst functional prognosis. Conclusions In our experience, factors associated with worse functional prognosis and quality of life were a poor preoperative performance status, female gender, operating on a recurrent lesion, involvement of the left corticospinal tract, and surgical or medical postoperative complications.