Associating IDH and TERT Mutations in Glioma with Diffusion Anisotropy in Normal-Appearing White Matter.

BACKGROUND AND PURPOSE: IDH and TERT mutations might infiltratively manifest within normal-appearing white matter with specific phenotypes such as microstructural changes undetectable by standard MR imaging contrasts but potentially associable with DTI variables. The aim of this retrospective glioma study was to statistically investigate IDH and TERT associations and classifications with DTI reported microstructure in normal-appearing white matter. MATERIALS AND METHODS: Retrospective data from patients imaged between March 2012 and February 2016 were analyzed by grouping them as IDH-TERT subgroups and by IDH and TERT mutation status. DTI variables in the IDH-TERT subgroups were first identified by the Kruskal-Wallis test, followed by Dunn-Sidák multiple comparisons with Bonferroni correction. IDH and TERT mutations were compared with the Mann-Whitney U test. Classification by thresholding was tested using receiver operating characteristic analysis. RESULTS: Of 170 patients, 70 patients (mean age, 43.73 [SD, 15.32] years; 40 men) were included. Whole-brain normal-appearing white matter fractional anisotropy (FA) and relative anisotropy (RA) (P = .002) were significantly higher and the contralateral-ipsilateral hemispheric differences, ΔFA and ΔRA, (P < .001) were significantly lower in IDHonly patients compared with TERTonly, with a higher whole-brain normal-appearing white matter FA and RA (P = .01) and ΔFA and ΔRA (P = .002) compared to double positive patients. Whole-brain normal-appearing white matter ADC (P = .02), RD (P = .001), λ2 (P = .001), and λ3 (P = .001) were higher in IDH wild-type. Whole-brain normal-appearing white matter λ1 (AD) (P = .003), FA (P < .001), and RA (P = .003) were higher, but Δλ1 (P = .002), ΔFA, and ΔRA (P < .001) were lower in IDH mutant versus IDH wild-type. ΔFA (P = .01) and ΔRA (P = .02) were significantly higher in TERT mutant versus TERT wild-type. CONCLUSIONS: Axial and nonaxial diffusivities, anisotropy indices in the normal-appearing white matter and their interhemispheric differences demonstrated microstructural differences between IDH and TERT mutations, with the potential for classification methods.

Anterior clinoidal meningiomas: analysis of 43 consecutive surgically treated cases.

BACKGROUND: Anterior clinoidal meningiomas are considered different from meningiomas of the medial sphenoid wing, but there is still some confusion about identification. The current classification scheme only considers tumour origin and invasion pattern around the clinoid process as indicators of resectability. However, the size of the tumour has important effects on surgical outcome. The purpose of this study was to analyze our clinical experience with anterior clinoidal meningiomas and refine the current classification scheme. METHOD: Forty-three consecutive cases of anterior clinoidal meningioma were retrospectively analyzed. All were surgically treated at the Marmara University Department of Neurosurgery, the Marmara University Institute for Neurological Sciences, and the Department of Neurosurgery at Acibadem Hospital between 1987 and 2006. A pterional approach was used in all cases. FINDINGS: The mean tumour volume was 34.2 +/- 46.6 cc. Sixteen (37.2%) of the tumours were giant (largest diameter >4 cm). Total surgical removal was achieved in 39 cases (90.7%) and subtotal removal in 4 cases (9.3%). Eight patients (18.6%) developed early postoperative complications. The median and range of follow-up time was 39, R = 99 (3, 102) months. Four (9.3%) of the 43 tumours recurred during follow-up and were treated with radiosurgery. CONCLUSION: Anterior clinoidal meningioma is a separate disease entity from other meningiomas of the medial third of the sphenoid wing. Relatively good outcomes can be stated in this specific subgroup if growth criteria competable with true diagnosis are fulfilled. Size should be incorporated into any classification scheme for determining clinical and surgical risk. The standard pterional approach is sufficient for removing anterior clinoidal meningiomas.

Tumor-biology and current treatment of skull-base chordomas.

Chordomas are rare, slow growing tumors of the axial skeleton, which derive from the remnants of the fetal notochord. They can be encountered anywhere along the axial skeleton, most commonly in the sacral area, skull base and less commonly in the spine. Chordomas have a benign histopathology but exhibit malignant clinical behavior with invasive, destructive and metastatic potential. Genetic and molecular pathology studies on oncogenesis of chordomas are very limited and there is little known on mechanisms governing the disease. Chordomas most commonly present with headaches and diplopia and can be readily diagnosed by current neuroradiological methods. There are 3 pathological subtypes of chordomas: classic, chondroid and dedifferentiated chordomas. Differential diagnosis from chondrosarcomas by radiology or pathology may at times be difficult. Skull base chordomas are very challenging to treat. Clinically there are at least two subsets of chordoma patients with distinct behaviors: some with a benign course and another group with an aggressive and rapidly progressive disease. There is no standard treatment for chordomas. Surgical resection and high dose radiation treatment are the mainstays of current treatment. Nevertheless, a significant percentage of skull base chordomas recur despite treatment. The outcome is dictated primarily by the intrinsic biology of the tumor and treatment seems only to have a secondary impact. To date we only have a limited understanding this biology; however better understanding is likely to improve treatment outcome. Hereby we present a review of the current knowledge and experience on the tumor biology, diagnosis and treatment of chordomas.

Gamma-knife radiosurgery in the treatment of trigeminal schwannomas.

BACKGROUND: Trigeminal nerve schwannomas account for 0.07%-0.28% of all intracranial tumours. Advances in skull base surgery have led to more aggressive resection of these tumours, but surgery may associated with development of new neurological deficits. METHODS: In this report, we analyse the long-term results 15 patients with newly diagnosed or residual/recurrent trigeminal schwannoma who underwent gamma-knife treatment. FINDINGS: During a mean 61 months of follow-up, MRI revealed reduction of tumour size in 13 and no size change in 2 patients. The tumour growth control rate was 100% and only 1 patient had transient facial numbness and diplopia. CONCLUSIONS: For patients with small to moderate size trigeminal schwannomas, gamma-knife radiosurgery is associated with good tumour control and a minimal risk of adverse radiation effects.

Efficacy of gamma-knife surgery for treating meningiomas that involve the superior sagittal sinus.

BACKGROUND: Meningiomas involving the superior sagittal sinus (SSS) are among the most challenging tumors to treat. Authors of some recent series have advocated total removal with SSS reconstruction. However gamma-knife surgery is a reasonable choice for these tumors. PATIENTS: This study focused on 43 cases of meningioma invading the SSS that were treated with gamma-knife therapy. Twenty-eight patients had undergone previous resection. The follow-up period after radiosurgery ranged from 24 to 86 months (median, 46 months). The median marginal dose was 15 Gy. RESULTS: During follow-up, 22 (51%) tumors decreased in size, 16 (37%) remained unchanged, and 5 (12%) expanded. The overall rate of tumor control with radiosurgery was 89%. CONCLUSION: When a small meningioma involves the SSS and the sinus is patent, the first-line treatment should be radiosurgery. If the tumor is large and the sinus is patent, we recommend gross total resection with no removal of SSS. If postoperative or follow-up MR imaging demonstrates residual tumor or recurrence, gamma-knife surgery should be performed. If a large meningioma has completely obliterated the SSS, our policy is to remove the tumor and all sinus tissue without reconstructing the SSS.

Intraoperative MR imaging: preliminary results with 3 tesla MR system.

UNLABELLED: Aim of this study is to present the initial clinical experience with 3 tesla intraoperative MR (ioMR). MATERIAL AND METHODS: The 3T MRI suite is built adjacent to the neurosurgical operation theatre. The magnet room and the operation theatre are interconnected by a door and both RF-shielded. Before the operation, the magnet (3T Trio, Siemens) and the console rooms are disinfected. Whenever imaging is needed during the operation, the door is opened and the patient is transferred from the operation table to the magnet cradle. Axial, sagittal and/or coronal TSE T2, SE T1 and 3D Flash T1 weighted images (4-6 mm section thickness, 1 mm interslice gap) are obtained according to the lesion. Total examination time is approximately 10 minutes. RESULTS: Twenty-six patients were examined with ioMR. There were ten female and seven male patients. Lesions were pituitary adenoma in 10, low grade glial tumor in 9, meningioma and high grade glial tumor in 2 each and metastasis, haemangioblastoma and chordoma in one each. Follow-up time was 1 to 9 months. In 16 patients the first intraoperative examination revealed gross total tumor excision. However, in 10 patients due to tumor remnants surgical intervention was continued and a second examination revealed gross total tumor excision in all. Postoperative routine MR examinations confirmed total tumor excision in all patients. No complication occurred in this series. CONCLUSION: This small group of patients examined with ioMR demonstrated that the procedure is simple, helpful in achieving gross total tumor excision without complications.

Microvascular decompression for trigeminal neuralgia: a long-term follow-up study.

In this report, we present our experience with microvascular decompression (MVD) as treatment for trigeminal neuralgia (TN) and discuss factors related to recurrence after this procedure. Between 1986 and 2004, 90 patients underwent MVD for treatment of idiopathic TN at the Marmara University Department of Neurosurgery and Marmara University Neurological Sciences Institute. Individuals with atypical and secondary forms of TN were excluded from the study. The patient characteristics, work-up findings, observations during surgery, and results of MVD for the 90 cases are reviewed. In 87 (97%) of the patients, exposure of the pontocerebellar angle revealed a vascular structure compressing the trigeminal nerve. In the patients with vascular compression, the problem vessel was an artery in 80 (92%) cases and a vein in 7 (8%) cases. In 77 cases, all symptoms were completely resolved by the operation. Ten patients experienced significant partial relief, and the intensity of the residual pain in these cases was not severe enough to require medication. Three patients experienced no improvement after MVD. There was no mortality associated with MVD in the 90 cases. The findings for our series of 90 patients with TN who underwent MVD indicate that this operation is an effective and reliable treatment for this condition. We recommend MVD as the first-line surgical approach for patients with TN who do not respond to medical management.

Outcome determinants of pterional surgery for tuberculum sellae meningiomas.

BACKGROUND: Current literature on tuberculum sellae meningiomas is very heterogenous due to wide variation in nomenclature, diagnostic and operative techniques. The aim of this study is specifically to analyze the results of pterional craniotomy for tuberculum sellae meningiomas. A homogenous cohort of 42 consecutively operated tuberculum sellae meningioma cases are reviewed with special emphasis on the effects of pterional microsurgery on visual outcome. METHODS: This is a retrospective clinical analysis. 42 consecutive patients operated upon during the period of 15 years in a single institution using standard imaging protocols and pterional microsurgery are presented and effect of various variables on visual outcome analysed. FINDINGS: 81% of the patients presented with visual symptoms. The mean duration of symptoms was 12 months. Tumour volumes ranged from 7.5 to 210 mm(3). A right sided pterional microsurgery was used in all patients. Complete resection rate was 81%. Vision improved in 58%, worsened in 14%. Non-visual morbidity was 7.1% and mortality was 2.4%. The follow up period of patients ranged from 3 to 192 months (median: 30 months). The mean was 37.5 months (SD = +/-36.7 months) and a recurrence rate of 2.4% was observed. CONCLUSIONS: A standard pterional craniotomy using microsurgical technique provides the necessary exposure enabling total removal while keeping the complications to a minimum. Upon analysis of our findings we found that patient age of more than 60, duration of visual symptoms longer than 1 year, severe visual symptomatology, predominantly vertical growth, presence of significant peri-tumoural oedema, absence of an intact arachnoid plane and subtotal removal were correlated with a dismal visual outcome.

Spinal meningiomas: evaluation of 41 patients.

AIM: Spinal meningiomas are relatively frequent intraspinal tumors. They constitute 25-46% of all primary spinal neoplasms. METHODS: Forty-one patients with spinal meningiomas surgically treated between 1986 and 2001 are reviewed in this report. There were 32 females and 9 males, aged 16 to 73 years old. Tumor location was cervical in 7 cases and thoracic in 34 cases. All tumors were intradural. All of the patients were operated by laminectomy in prone position. RESULTS: Total excision was achieved in 40 (98%) patients and subtotal excision in 1(2%). The majority of the tumors were meningothelial (42%) or psammomatous (25%). There was no surgical mortality. Four patients (10%) suffered from morbidity: One patient with CSF fistula, 1 deep venous thrombosis, 1 case with paraparesis and 1 wound infection was seen. Neither multiple meningiomas nor malign meningiomas were seen in our series. CONCLUSIONS: Spinal meningiomas are benign tumors and should be excised totally. If the preoperative neurological status is not complicated, fairly good outcome can be achieved.

Ectopic pituitary adenoma located at the pituitary stalk. Case report.

Suprasellar located ectopic pituitary adenomas are unusual tumors. We report a rare case of suprasellar prolactinoma arising from the pars tuberalis in a 37-year-old woman. Menstrual disregulation and bitemporal hemianopsia were the main complaints. Blood tests revealed hyperprolactinemia. In magnetic resonance the tumor was totally supradiaphragmatic. Pterional craniotomy and total tumor excision was performed. The pituitary stalk was preserved. Histopathologic diagnosis was a pituitary adenoma immunoreactive for prolactin. Pituitary hormonal functions returned to normal at 6 months postoperatively. No complications were seen in the postoperative period. An ectopic adenoma should be suspected in a patient with suprasellar tumor and hyperprolactinemia. Surgical excision of this tumor may result with normal pituitary functions and normal visual acuity.

Microsurgical anatomy of the lateral walls of the pituitary fossa.

BACKGROUND: The aim was to evaluate the microanatomy of the lateral wall of the pituitary fossa in cadavers. METHODS: Histological sections of sellar-parasellar specimens from 13 cadaver heads were examined. The thickness of the pituitary capsule and inferior and lateral walls of the pituitary fossa were measured, and the collagenous structure of these layers was evaluated. FINDINGS: The pituitary gland is enveloped by a tough, thin, fibrous capsule. The inferior wall of the pituitary fossa is composed of relatively thick dura (mean thickness in the 13 specimens, 171 microm). Each lateral wall of the fossa has a thin layer of dura (mean thickness in the specimens, 85 microm). The pituitary capsule and the dural layers in the lateral and inferior walls of the fossa were immunopositive for collagen types I and II. Collagen types III, IV and V were detected only in the pituitary capsule. CONCLUSIONS: Weakness of the lateral walls of the pituitary fossa and the degree to which collagen fibres in the pituitary capsule have been biochemically damaged are important factors in infiltration of the cavernous sinus by a pituitary adenoma.

Relief of hemifacial spasm after radiosurgery for intracanalicular vestibular schwannoma.

Secondary hemifacial spasm due to vestibular schwannoma is very rare. This is the first reported case of hemifacial spasm responsive to gamma knife radiosurgery in a patient with an intracanalicular vestibular schwannoma. Both the resolution of the spasm as well as tumor growth control were achieved with a single session of gamma knife radiosurgery. We report a 49-year-old male patient with a 6-month history of right-sided hearing loss and hemifacial spasm. MR examination revealed an intracanalicular vestibular schwannoma. The patient was treated with radiosurgery and received 13 Gy to the 50 % isodose line. Tumor growth control was achieved and no change in the tumor volume was present at the last follow-up at 22 months. The hemifacial spasm completely resolved after one year. Surgical removal of the presumably causative mass lesion has been reported to be the sole treatment in secondary hemifacial spasm. This case report indicates that it may be responsive to gamma knife radiosurgery. Whether or not this might be a treatment option in selected refractory cases of hemifacial spasm remains to be defined.

A retrospective review of cervical corpectomy: indications, complications and outcome.

BACKGROUND: Cervical corpectomy is a common spinal surgery procedure used to decompress the spinal cord in numerous degenerative, traumatic and neoplastic conditions. The aim of this study was to investigate the indications, complications and outcomes in past cervical corpectomy cases at one centre. METHOD: 72 patients who underwent cervical corpectomy between February 1992 and June 2001 were retrospectively investigated. FINDINGS: The indications for this operation were degenerative spondylitic disease (26 cases; 36.1%), trauma (18 cases; 25%), tumour (11 cases; 15.3%), infection (10 cases; 13.9%), and ossification of the posterior longitudinal ligament (7 cases; 9.7%). Thirty-seven patients (51.4%) underwent one-level corpectomy, and 35 (48.6%) underwent two-level corpectomy. Autografts were used in 13 cases (18.1%) and allografts were used in 59 cases (81.9%). Anterior plate-screw fixation was performed in all cases. There were 31 postoperative complications in 15 (20.8%) patients. Twelve of the complications were surgical, 5 were graft-related, 7 were plating-related, and 7 were medical. Solid bony fusion was achieved in 65 (92.9%) of the 70 surviving patients. The mean follow-up time was 23.4 months. An overall favourable outcome was achieved in 88% of cases. CONCLUSION: The outcomes in this series indicate that cervical corpectomy is an effective method for treating traumatic lesions, degenerative disease, tumours and infectious processes involving the anterior and middle portions of the cervical spine.

Anterior transcallosal approach to the colloid cysts of the third ventricle: case series and review of the literature.

OBJECTIVES: To evaluate the results of the anterior transcallosal approach to the colloid cysts of the third ventricle. PATIENTS AND METHODS: A retrospective analysis of the patients operated on between 1986 and 2003 was carried out. There were 19 patients (10 female, 9 male) with a median age of 43. The main presenting symptom was headache. One of the patients presented with acromegaly due to a pituitary tumor. The size of the cysts ranged from 15 to 43 mm. An anterior transcallosal approach was used in all patients. RESULTS: The cysts were excised totally in all cases. Postoperatively no recent memory loss has been detected in any patient. One patient with hemorrhagic papil stasis experienced temporary visual worsening. In one patient with hydrocephalus a ventriculoperitoneal shunt was needed. One patient with postoperative superior frontal gyrus venous infarction had a seizure. The follow-up period was from 1 month to 13 years (mean 5.2 years). To date, there has been no recurrence so far. CONCLUSION: The anterior transcallosal approach is a safe method for the treatment of third ventricular colloid cysts.

Radiosurgical treatment of cavernous sinus cavernous haemangiomas.

BACKGROUND: The objective of this report is to evaluate the effects of radiosurgery on cavernous sinus cavernous haemangiomas (CSCHs). METHOD: Five cases of CSCHs are presented in this report. One of them was diagnosed only neuroradiologically. Other patients underwent surgery and were then referred to Gamma Knife radiosurgery for residual tumours. The cohort consisted of 3 male and 2 female patients with median age of 42 (37-60). The volume of the tumours ranged between 3.8-6.5 cc. They were treated with a marginal dose of 14 to 16 Gy (mean 15 Gy). Findings. In the mean follow-up period of 32 months (6-52 months) all of the tumours decreased in size. There were no complications related to radiosurgery. CONCLUSION: Gamma Knife radiosurgery is an effective method in the treatment of CSCH, over the period of follow-up described.

Multimodality management of 26 skull-base chordomas with 4-year mean follow-up: experience at a single institution.

OBJECTIVE: To analyze a series of patients with pathologically confirmed skull-base chordoma, and to develop an algorithm for the management of this challenging disease based on the data, our experience, and the current literature. MATERIAL AND METHODS: Between the years 1986 and 2001, 26 chordoma patients received multimodality treatment with various combinations of conventional surgery, skull-base surgical techniques, and gamma-knife surgery at the Marmara University Faculty of Medicine. A total of 57 procedures (43 tumor excision surgeries, 7 gamma-knife procedures, and 7 other operations to treat complications) were performed. The mean follow-up period was 4 years (48.5 months). Karnofsky scoring was used to follow the patients' clinical conditions, and magnetic resonance image analysis was used to measure tumor volume over time. RESULTS: Seven patients died during follow-up. Two of the deaths were due to surgical complications, four resulted from clinical deterioration related to tumor recurrence, and one was unrelated to neoplasia. The rate of tumor recurrence after the first surgical treatment was 58%. Residual tumor volume was lower in the cases in whom skull-base approaches were used as first-line management. The 19 survivors showed little change in clinical status from initial diagnosis to the most recent follow-up check. The mean follow-up time after gamma-knife treatment was 23.3 months. During this period, mean tumor volume increased 28% above the mean volume at the time of gamma-knife surgery. The mean Karnofsky score decreased by 6% during the same time frame. CONCLUSIONS: The most effective first-line treatment for chordoma patients is surgery. The findings for residual tumor volume indicated that skull-base approaches are the best surgical option, and the complication rates for these techniques are acceptable. However, it is rare that surgery ever biologically eradicates this disease, and the data showed that these chordomas almost always progress if the tumor volume at the time of diagnosis exceeds 20 cm(3). Based on our experience and the biological character of the disease, we now advocate radiosurgical treatment (gamma-knife in our case) immediately after the first-line skull-base surgery when the tumor residual volume is <30 cm(3).

How to write an experimental research paper.

The art and practice of academic neurosurgery are mastered by defining and learning the pertinent basic principles and skills. This article aims to present general guidelines to one of the many roles of a neurosurgeon: Writing an experimental research paper. Every research report must use the "IMRAD formula: introduction, methods, results and discussion". After the IMRAD is finished, abstract should be written and the title should be "created". Your abstract should answer these questions: "Why did you start?, what did you do?, what answer did you get?, and what does it mean?". Title of the research paper should be short enough to catch glance and memory of the reader and be long enough to give the essential information of what the paper is about. Writing about the results of the experiment is no easier than the research itself. As surgery, writing a scientific paper is also an improvisation, but general principles should be learned and used in practice. The most effective style of learning basic skills to construct a research paper is the "trial and error" type.

The effects of quantum energy surgical device and of bipolar coagulation: a comparative experimental study.

OBJECTIVE: The quantum energy surgical device (QESD) employs an innovative, "no-touch" thermal coagulation, incision and evaporation technique in which thermal energy is delivered to tissue in the format of high-energy neutral argon gas atoms. The aim of this study is to compare QESD and bipolar coagulation (BC) through assessment of both haemostasis and histological damage to isolated femoral arteries of rats. METHODS: Sixty rats were randomly divided into acute and short-term experimental groups. In the acute group (n=20) histopathological evaluation was performed immediately following coagulation, whereas in the short-term experimental group (n=20) the evaluation was performed 10 days later. Each sham group consisted of ten rats. Viewed under the surgical microscope, only normal-appearing, freshly sectioned, and bleeding femoral arteries were studied. Right femoral arteries subject to QESD coagulation, and left femoral arteries to BC. Haemorrhaging was controlled using the minimal coagulation time necessary to stop it. All vascular layers, including endothelium, internal elastic lamina, media and adventitia were examined histologically and ultrastructurally in a "blind" fashion to critically compare morphological damage due to QESD and BC. RESULTS: Surgical haemostasis induced by QESD was found to be as safe as BC. Light microscopy revealed more marked histopathological changes in the BC than in the QESD group. These involved mainly the endothelial and medial compartments and, at the ultrastructural level, consisted of endothelial degeneration and exfoliation, irregularity of internal elastic lamina, degeneration, and loss of medial smooth muscle. CONCLUSION: The results indicate that QESD coagulation induces significantly less histological damage than does BC. Thus QESD coagulation is a safe, less tissue destructive, and equally effective method of haemostasis.

Experimental trigeminal glycerol injection in dogs: histopathological evaluation by light and electron microscopy.

We investigated the effects of percutaneous gasserian glycerol injection in dogs and reviewed the histopathological changes. Experiments were performed in 16 adult healthy mongrel dogs. In group 1 (8 dogs) normal saline and in group 2 (8 dogs) pure glycerol was injected in the right trigeminal ganglion. After these procedures, dogs in each group were sacrificed after 24 h (3 dogs), 7 days (3 dogs), 21 days (2 dogs). The trigeminal ganglion and nerve of both sides were removed by using microsurgical techniques and examined by light and electron microscopy. Group 1: in all sections, nerve cells, myelinated and nonmyelinated fibers revealed normal patterns with slight fibrosis. Group 2: in all sections, myelinated fibers showed disintegration and swelling of the myelin sheath, rupture of axon continuity, destruction of basal lamina, deformation of the myelin-axon relationship by both light microscopy and electron microscopy. The sections examined by electron microscopy also showed axonolysis in nonmyelinated fibers. The changes after 7 and 21 days were less prominent than after 24 h. In the left sides, there are no pathological changes. Glycerol has a neurolytic effect on the dog's trigeminal ganglion. These effects were not specific and selective for myelinated and nonmyelinated nerve fibers.