Evaluation of Olfactory Outcome After Frontolateral Approach for Treatment of Suprasellar Tumors.

OBJECTIVE: We present the findings of our prospective study assessing olfactory function outcome in patients undergoing a frontolateral approach for the resection of suprasellar lesions. METHODS: Eighteen consecutive patients (7 females, 11 males) surgically treated at our institute for suprasellar tumors were included in this prospective study. Olfactory function was evaluated at the admission and 14 days after the surgery using the standard 12-item "Sniffin' Sticks" screening (SSS) test. The olfactory outcome was correlated to the following variables: tumor type, size, consistency, and extent of vertical and lateral growth. RESULTS: Preoperative and postoperative SSS test mean values were, respectively, 9.11 and 8.72 (not significant: P = 0.274). In only 1 case (5%), with larger suprasellar extension, the difference between preoperative and postoperative SSS was ≥3 (reduction of 5 points). At the subjective evaluation, no patient stated a deficit in smelling. CONCLUSION: The frontolateral craniotomy is a minimally invasive route to treat suprasellar tumors and has a low approach-related morbidity. It allows tumor resection with low risk for the olfactory function. A risk factor for postoperative olfactory deficit could be significant brain retraction.

Assessment of quantitative corticospinal tract diffusion changes in patients affected by subcortical gliomas using common available navigation software.

OBJECTIVE: The aim of this study is to analyze the quantitative DTI parameters of the CST in patients suffering from subcortical gliomas affecting the CST using generally available navigation software. METHODS: A retrospective study was conducted on 22 subjects with diagnosis of primary cerebral glioma and preoperative motor deficits. Exclusion criteria were: involvement of motor cortex, lesion involving both hemispheres, previous surgical treatment. All patients were studied using magnetic resonance imaging (MRI) with diffusion tensor imaging (DTI) sequences. Volume, fractional anisotropy (FA) and mean diffusivity value (MD) of the entire CSTs were estimated. Moreover, distance from midline, diameters, FA and MD were calculated on axial images at the point of minimal distance between tumor and CST. Statistical analysis was performed. RESULTS: There was a statistically significant difference of CST volume between affected and non-affected hemispheres (p<0.01). Mean overall/local FA, overall/local MD and sagittal diameter of CST were also significantly different between the two sides (p<0.05). Correlation tests resulted positive between the shift of CST and overall/local MD. Moreover there is significance between CST volume of tumor hemisphere and preoperative duration of motor deficits (p<0.05). CONCLUSION: The present study has demonstrated for the first time a significant difference of DTI based quantitative parameters of the CST between a tumor affected and a non-affected hemisphere in patients with a corresponding motor deficit. This preliminary data suggests a correlation between DTI based integrity of CST and its function.

Prognostic Significance of Peritumoral Edema in Patients With Vestibular Schwannomas.

BACKGROUND: Peritumoral edema (PTE) in skull base meningiomas correlates to the absence of an arachnoid plane and difference in outcome. In vestibular schwannomas (VS), PTE and its significance for microsurgery and outcome have never been systematically evaluated. OBJECTIVE: To evaluate whether PTE correlates with tumor characteristics, the presence of an arachnoid plane, and outcome. METHODS: A retrospective study of the institutional database. PTE was evaluated on fluid-attenuated inversion recovery magnetic resonance images. Preoperative patient data and intraoperative tumor features (presence of tumor pseudocapsule, vascularity, degree of adhesion/invasion of the arachnoid) were noted. Outcome measures were completeness of removal, neurological outcome, and complication rate. These parameters in patients with PTE (group A) were correlated to those in matched series without edema (group B). RESULTS: Thirty patients presented with PTE (5%). The mean VS size was 3.4 cm. No major differences in the degree of adhesion or presence of an arachnoid plane were found. VS with PTE were more frequently hypervascular (26.7% in group A vs 6.7% in group B). The presence of PTE in VS was not related to surgical radicality. VS with PTE had worse early postoperative facial nerve function, but at 12 months, there was no major difference. VS with PTE were prone to cause postoperative hemorrhages in the tumor bed. CONCLUSION: PTE in VS does not correlate with the degree of tumor adhesion and the presence of an arachnoid dissection plane. The radicality of tumor removal and long-term functional outcome in patients with and without PTE was similar. VS with PTE are more vascular and prone to cause postoperative hemorrhages. Therefore, meticulous hemostasis is advisable.

Operative management of patients with radiosurgery-related trigeminal neuralgia: analysis of the surgical morbidity and pain outcome.

OBJECT: Trigeminal neuralgia (TGN) occurring after radiosurgical treatment of cerebellopontine or petroclival tumors may be very difficult to control. Our aim was to determine the efficacy of neurosurgical treatment in regards to pain control and to evaluate the procedure-related complication and morbidity rates. METHODS: Retrospective study of a series of operated patients with radiosurgery-induced TGN. The primary goal of the surgery was to inspect and decompress the trigeminal nerve; the second goal was to remove the tumor remnant completely, if safely feasible. The main outcome measures were pain control, time to onset of pain relief and its duration, occurrence of new neurological deficits or worsening of the existing one and completeness of tumor removal. RESULTS: The four patients met the inclusion criteria: 2 with vestibular schwannomas, 1 with petroclival meningioma and 1 with an epidermoid. TGN occurred 12-60 months after radiosurgery (mean 39 months). At presentation the pain attacks occurred multiple timesdaily and lasted from a few seconds to 2-3min. The Complete tumor removal via the retrosigmoid approach was achieved in all cases. There were no major operative complications or persistent morbidity, besides one patient with trochlear nerve palsy. All patients experienced immediate pain relief after surgery. At follow-up (median duration - 42.5 months) the three patients reported complete pain resolution. One patient had occasional slight pain but did not need any medications. CONCLUSION: Surgery is safe and effective treatment option of patients with intractable radiosurgery-induced TGN. It leads to excellent pain control and is curative in regards to the neoplastic disease.

Feasibility of cervical intramedullary diffuse glioma resection using intraoperative magnetic resonance imaging.

Intraoperative magnetic resonance imaging (iopMRI) actually has an important role in the surgery of brain tumors, especially gliomas and pituitary adenomas. The aim of our work was to describe the advantages and drawbacks of this tool for the surgical treatment of cervical intramedullary gliomas. We describe two explicative cases including the setup, positioning, and the complete workflow of the surgical approach with intraoperative imaging. Even if the configuration of iopMRI equipment was originally designed for cranial surgery, we have demonstrated the feasibility of cervical intramedullary glioma resection with the aid of high-field iopMRI. This tool was extremely useful to evaluate the extent of tumor removal and to obtain a higher resection rate, but still need some enhancement in the configuration of the headrest coil and surgical table to allow better patient positioning.

Microsurgical or radiosurgical management of intracranial cavernomas.

Cranial cavernous malformations (CCMs) constitute a heterogeneous group of lesions that tend to change dynamically over time with related periods of repeated exacerbation and alternating periods of remission. The decision on their management is based on estimating the inherent risk of further morbidity and the risk/benefit related to the particular treatment mode. Incidentally detected CCMs or lesions in asymptomatic patients presenting without major hemorrhage are best followed up. Complete resection of a CCM is the only healing option and is indicated for symptomatic or hemorrhagic lesions. In the large published series 83-92 % of the patients improved or remained unchanged after surgery, with only 8-11 % showing significant deterioration. For most patients, quality of life is improved. Analysis of the risk/benefit ratio for radiosurgery shows that it should not be regarded as an alternative option: It confers limited protection against bleeding and is related to a certain morbidity risk. In the subgroup of patients with symptomatic or hemorrhagic CCMs in locations that preclude surgical resection with acceptable risks, we recommend follow-up. The senior author is following a group of more than 80 such patients, and the vast majority remain free of hemorrhage and symptoms.

The dedicated endoscopic operating room.

BACKGROUND: The establishment of neuroendoscopy has been one of the major achievements in neurosurgery in the last 2 decades. The use of the endoscope increases efficacy and safety in each procedure. METHODS: The integration of endoscopy with other operating techniques or imaging technologies enhances the safety and reliability of the technique. RESULTS: The efficacy of the procedures, patient safety, and extent of resection have been increased by the integration of endoscopy with all of these sophisticated operative tools and imaging sources. Endoscopy has led to shortening of operative time and of the duration of hospital stay. CONCLUSIONS: A dedicated endoscopic operating room should provide workflow optimization, ergonomic solutions, and highest safety standards for the patient.

Intradural extraneural bilobate ganglion cyst of the atlanto-occipital joint compressing the hypoglossal nerve.

Ganglion cysts (ganglia) are benign lesions of the soft tissue arising in the periarticular space. We present a 54-year-old woman with a 5-month history of headache and weakness of the tongue with deviation to the left side who had a rare extraneural intradural bilobate ganglion cyst of the atlanto-occipital joint compressing the hypoglossal nerve. An MRI showed a bilobate cystic lesion in the premedullary cistern on the left side at the level of the hypoglossal canal. This lesion was removed using a lateral suboccipital approach in the semi-sitting position with removal of the C1 hemiarch. The lesion proved to be a ganglion cyst on histopathology. Intracranial juxtafacet (ganglion and synovial) cysts compressing the hypoglossal nerve should be considered in the differential diagnosis with other lesions of this region. Although there was no recurrence at 30-month follow-up, there was no significant improvement of the tongue weakness. We describe our surgical strategy and discuss the pathogenesis of the cyst.

Surgical treatment of patients with vestibular schwannomas after failed previous radiosurgery.

OBJECT: An increasing number of patients with vestibular schwannomas (VSs) are being treated with radiosurgery. Treatment failure or secondary regrowth after radiosurgery, however, has been observed in 2%-9% of patients. In large tumors that compress the brainstem and in patients who experience rapid neurological deterioration, surgical removal is the only reasonable management option. METHODS: The authors evaluated the relevance of previous radiosurgery for the outcome of surgery in a series of 28 patients with VS. The cohort was further subdivided into Group A (radiosurgery prior to surgery) and Group B (partial tumor removal followed by radiosurgery prior to current surgery). The functional and general outcomes in these 2 groups were compared with those in a control group (no previous treatment, matched characteristics). RESULTS There were 15 patients in Group A, 13 in Group B, and 30 in the control group. The indications for surgery were sustained tumor enlargement and progression of neurological symptoms in 12 patients, sustained tumor enlargement in 15 patients, and worsening of neurological symptoms without evidence of tumor growth in 1 patient. Total tumor removal was achieved in all patients in Groups A and B and in 96.7% of those in the control group. There were no deaths in any group. Although no significant differences in the neurological morbidity or complication rates after surgery were noted, the risk of new cranial nerve deficits and CSF leakage was highest in patients in Group B. Patients who underwent previous radiosurgical treatment (Groups A and B) tended to be at higher risk of developing postoperative hematomas in the tumor bed or cerebellum. The rate of facial nerve anatomical preservation was highest in those patients who were not treated previously (93.3%) and decreased to 86.7% in the patients in Group A and to 61.5% in those in Group B. Facial nerve function at follow-up was found to correlate to the previous treatment; excellent or good function was seen in 87% of the patients from the control group, 78% of those in Group A, and 68% of those in Group B. CONCLUSIONS: Complete microsurgical removal of VSs after failed radiosurgery is possible with an acceptable morbidity rate. The functional outcome, however, tends to be worse than in nontreated patients. Surgery after previous partial tumor removal and radiosurgery is most challenging and related to worse outcome.

Restorative neurosurgery of the cortex: resections of pathologies of the central area can improve preexisting motor deficits.

Different pathologies such as tumors or focal dysplasias can be removed from eloquent areas without subsequent functional deficits. What has not yet been established is the removal of structural abnormalities in sensorimotor area associated with substantial neurological deficits performed in order to accomplish functional improvement. Neurosurgical resections in highly eloquent areas thus hold promise to open a new field--achievement of functional restitution even in cases with long-standing deficits. We present four exemplary cases where the removal of different structural abnormalities led to an impressive improvement of motor deficits. One patient had bilateral ischemic lesion resulting from perinatal hypoxia, one cavernoma, and two focal cortical dysplasias. All presented with motor or sensorimotor deficits and three had long-standing therapy refractory focal seizures. The extent of safe lesionectomy was determined using fMRI, fiber tracking, and PET studies and performed with intraoperative functional neuronavigation guidance and cortical stimulation. The achievement of the planned amount of resection was verified with an intraoperative MR examination. New persisting neurological deficits after surgery were not registered. One patient had temporary worsening of the right hand weakness that rapidly resolved. One patient was completely seizure free, and in two patients, the seizures' frequency, duration, and severity were significantly reduced. The preoperatively disturbed motor function improved in all four cases in the course of days or weeks. In summary, pathological processes affecting the sensorimotor area may cause focal seizures and/or compromise sensorimotor functions. Lesionectomy may accomplish not only the amelioration of focal seizures but also substantial functional improvement.

Sphenoid sinus pyocele after transsphenoidal approach for pituitary adenoma.

Transsphenoidal pituitary adenoma surgery is related to a low morbidity rate. The complications that can occur are classified as intra- and extracranial. The aim of the study is to discuss one group of these complications involving the sphenoid sinus: mucocele and its possible transformation into pyocele. We evaluate clinical presentation, management strategy and the outcome after long-term follow-up presenting an explicative case and a review of the literature. A patient presented to our outpatient clinic 8 months after transsphenoidal surgery for selective removal of a pituitary adenoma because of an acute onset of frontal headache during an airplane travel, fever and pulsating sensation in left eye and ear. MRI revealed a contrast-enhancing lesion in the left inferior portion of the sphenoid sinus. An endonasal endoscopic revision of the sphenoid sinus was performed. After opening of the scar to enter in the left sinus a pyocele was found and treated with drainage and marsupialisation. Development of sphenoid sinus pyocele is an extremely rare postoperative complication of transsphenoidal surgery. This lesion should be taken in consideration in patients presenting with retroorbital headache of acute onset and fever after pituitary surgery. Diagnosis can be suspected on the MRI studies and confirmed by a targeted flexible endoscope examination. Endoscopic drainage with wide opening of the sphenoid sinus and marsupialisation is the treatment of choice to avoid recurrences.

Diffusion tensor imaging-based fiber tracking for prediction of the position of the facial nerve in relation to large vestibular schwannomas.

OBJECT: The reliable preoperative visualization of facial nerve location in relation to vestibular schwannoma (VS) would allow surgeons to plan tumor removal accordingly and may increase the safety of surgery. In this prospective study, the authors attempted to validate the reliability of facial nerve diffusion tensor (DT) imaging-based fiber tracking in a series of patients with large VSs. Furthermore, the authors evaluated the potential of this visualization technique to predict the morphological shape of the facial nerve (tumor compression-related flattening of the nerve). METHODS: Diffusion tensor imaging and anatomical images (constructive interference in steady state) were acquired in a series of 22 consecutive patients with large VSs and postprocessed with navigational software to obtain facial nerve fiber tracking. The location of the cerebellopontine angle (CPA) part of the nerve in relation to the tumor was recorded during surgery by the surgeon, who was blinded to the results of the fiber tracking. A correlative analysis was performed of the imaging-based location of the nerve compared with its in situ position in relation to the VS. RESULTS: Fibers corresponding to the anatomical location and course of the facial nerve from the brainstem to the internal auditory meatus were identified with the DT imaging-based fiber tracking technique in all 22 cases. The location of the CPA segment of the facial nerve in relation to the VS determined during surgery corresponded to the location of the fibers, predicted by the DT imaging-based fiber tracking, in 20 (90.9%) of the 22 patients. No DT imaging-based fiber tracking correlates were found with the 2 morphological types of the nerve (compact or flat). CONCLUSIONS: The current study of patients with large VSs has shown that the position of the facial nerve in relation to the tumor can be predicted reliably (in 91%) using DT imaging-based fiber tracking. These are preliminary results that need further verification in a larger series.

Patient acceptance of awake craniotomy.

OBJECTIVES: The aim of this study was to objectively assess the patients' acceptance for awake craniotomy in a group of neurosurgical patients, who underwent this procedure for removal of lesions in or close to eloquent brain areas. PATIENTS AND METHODS: Patients acceptance for awake craniotomy under local anesthesia and conscious sedation was assessed by a formal questionnaire (PPP33), initially developed for general surgery patients. The results are compared to a group of patients who had brain surgery under general anesthesia and to previously published data. RESULTS: The awake craniotomy (AC) group consisted of 37 male and 9 female patients (48 craniotomies) with age ranging from 18 to 71 years. The general anesthesia (GA) group consisted of 26 male and 15 female patients (43 craniotomies) with age ranging from 26 to 83 years. All patients in the study were included in the questionnaire analysis. In comparison to GA the overall PPP33 score for AC was higher (p=0.07), suggesting better overall acceptance for AC. The subscale scores for AC were also significantly better compared to GA for the two subscales "postoperative pain" (p=0.02) and "physical disorders" (p=0.01) and equal for the other 6 subscales. The results of the overall mean score and the scores for the subscales of the PPP33 questionnaire verify good patients' acceptance for AC. CONCLUSION: Previous studies have shown good patients' acceptance for awake craniotomy, but only a few times using formal approaches. By utilizing a formal questionnaire we could verify good patient acceptance for awake craniotomy for the treatment of brain tumors in or close to eloquent areas. This is a novel approach that substantiates previously published experiences.

Two-dimensional high-end ultrasound imaging compared to intraoperative MRI during resection of low-grade gliomas.

Ultrasound (US) is being used increasingly in intraoperative imaging. Its reliability in identifying low-grade gliomas (LGG), however, has not been shown definitively. We compared the quality and reliability of high-end two-dimensional (2D) ultrasound (US) and 1.5 Tesla intraoperative MRI (iopMRI) images in 11 patients with LGG. The parameters evaluated were: tumor border; internal structure; vascularity, location, and relation to landmarks and vessels; and accuracy in detecting remnants. Both methods allowed good visualization of internal characteristics of the tumor and its location. The tumor border was clear on 10 of 11 MRI and on 9 of 11 US. During surgery, however, the quality of US images diminished, leading to some difficulties in interpretation. One small superficial remnant was not identified and in one patient an artifact was falsely interpreted as a remnant. While iopMRI appeared superior for visualizing different stages of hemispheric LGG resection, 2D US still allows accurate initial tumor delineation and for almost real-time control of tumor resection.

Identification of venous variants in the pineal region with three-dimensional preoperative magnetic resonance imaging navigation in patients harbouring tumors in this area: significance for surgical approach to the lesion.

OBJECT: The purpose of this study was to identify the anatomy of pineal region venous complex using neuronavigation software when distorted by the presence of a space-occupying lesion and to describe the anatomical relationship between lesion and veins. Moreover we discuss its influence on the choice of the surgical strategy. METHODS: Of the 33 patients treated at our Institute for pineal region tumors between 2003 and 2008 we used the neuronavigation software to depict the venous system of the pineal region in 14 patients. We focused on depiction of the basal vein of Rosenthal (BV), the internal cerebral vein (ICV) and the vein of Galen: connection patterns between the veins and the type of anatomical distortion caused by the lesion were investigated and classified. RESULTS: Using the neuronavigation software for three-dimensional (3D) reconstruction of MRI images the ICV was clearly depicted in all patients on both sides (100%). Last segment of the BV was identified in 25 sides on a total of 28 (89.3%) and absent in 3 of the 28 sides (10.7%). Studying the distortion effect of the tumor on the galenic venous system, three directions of displacement were observed: craniocaudal, anteroposterior and lateral. Seven patients presented a cranial dislocation, 5 patients caudal dislocation and there was no craniocaudal shift in 2 patients. Considering the anteroposterior displacement: 3 subjects showed an anterior shift of the veins, 5 subjects posterior shift and no anterioposterior shift was present in 6 patients. Only 2 of the 14 patients presented lateral displacement of the veins. The principal approaches used in this series were: supracerebellar infratentorial and interhemispheric parieto-occipital. The craniocaudal displacement of the pineal veins seems to be the most important for the choice of the approach. CONCLUSION: The galenic venous system has a central role in the surgery pineal region tumors. Our study demonstrates that the architecture of the pineal veins and their anatomical relationship with the lesion can be depicted with great accuracy by using 3D neuronavigation software in order to facilitate surgical planning and intraoperative orientation.

Typical 3-D localization of tumor remnants of WHO grade II hemispheric gliomas--lessons learned from the use of intraoperative high-field MRI control.

BACKGROUND: Complete resection of grade II gliomas might prolong survival but is not always possible. The goal of the study was to evaluate the location of unexpected grade II gliomas remnants after assumed complete removal with intraoperative (iop) MRI and to assess the reason for their non-detection. METHODS: Intraoperative MR images of 35 patients with hemispheric grade II gliomas, acquired after assumed complete removal of preoperatively segmented tumor/tumor part, were studied for existence of unexpected tumor remnants. Remnants location was classified in relation to tumor cavity in axial and vertical planes. The relation of remnants to retractor position and to surgeons' visual axis, and the role of neuronavigational accuracy and brain shift, was assessed. RESULTS: Unexpected remnants were found in 16 patients (46%). In 29.2%, the reason was loss of neuronavigational accuracy. In 21%, remnants were in that part of the resection cavity, where the retractor had been placed initially. In 17%, they were deeply located and hidden by the retractor. In 13%, remnants were hidden by the overlapping brain; and in 21%, the reason was not obvious. In 75% of all temporomesial tumors, remnants were posterolateral to the resection cavity. Remnants detection with iopMRI and update of neuronavigational data allowed further removal in 14 of 16 cases. In two cases, remnant location precluded their removal. CONCLUSIONS: Distribution of tumor remnants of grade II gliomas tends to follow some patterns. Targeted attention to the areas of possible remnants could increase the radicality of surgery, even if intraoperative imaging is not performed.

Hydrocephalus associated with vestibular schwannomas: management options and factors predicting the outcome.

OBJECT: The current, generally accepted optimal management for hydrocephalus related to vestibular schwannomas (VSs) is primary tumor removal, with further treatment reserved only for patients who remain symptomatic. Previous studies have shown, however, that this management can lead to an increase in surgery-related complications. In this study, the authors evaluated their experience with the treatment of such patients, with the aim of identifying the following: 1) the parameters correlating to the need for specific hydrocephalus treatment following VS surgery; and 2) patients at risk for developing hydrocephalus-related complications. METHODS: This was a retrospective study of a 400-patient series. The complication rates and outcomes following primary hydrocephalus treatment versus primary VS removal were compared. Patients undergoing primary tumor removal were further subdivided on the basis of the need for subsequent hydrocephalus treatment. The 3 categories of parameters tested for correlation with the need for such subsequent treatment as well as with heightened risk for developing complications were patient-, tumor-, and hydrocephalus-related. RESULTS: Of the entire series, 53 patients presented with hydrocephalus. Forty-eight of 53 patients underwent primary VS surgery, of whom 42 (87.5%) did not require additional hydrocephalus treatment. Of the 6 patients who did require additional hydrocephalus treatment, only 3 ultimately required a VP shunt. Factors correlating to the need of hydrocephalus treatment after VS removal were large tumor size, irregular tumor surface, and severe preoperative hydrocephalus. Patients with a longer symptom duration prior to surgery, those with polycyclic tumors, or with inhomogeneous VS, were at heightened risk for the development of CSF leaks. The general and functional outcome of surgery showed no correlation to the presence of preoperative hydrocephalus. CONCLUSIONS: Primary tumor removal is the optimum management of disease in patients with VS with associated hydrocephalus; it leads to resolution of the hydrocephalus in the majority of cases, and the outcome is similar to that of patients without hydrocephalus. Certain factors may aid in identifying patients at risk for developing persistent hydrocephalus as well as those at risk for CSF leaks.