Biomedical subjects

M N Pamir

Publications and source records attributed to M N Pamir.

At least 19 recordsLinked to original sources

PubMed2006

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.

Brain Neoplasms↗

PubMed2005

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.

Adult↗

PubMed2005

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.

Adult↗

PubMed2005

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.

Adolescent↗

PubMed2005

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.

Adult↗

PubMed2004

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.

Adult↗

PubMed2004

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).

Adolescent↗

PubMed2004

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.

Adult↗

PubMed2004

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.

Hemifacial Spasm↗

PubMed2004

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.

Adolescent↗

PubMed2002

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.

Curriculum↗

PubMed2002

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.

Animals↗

PubMed2002

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.

Animals↗

PubMed2001

Diastematomyelia and spinal teratoma in an adult. Case report.

Diastematomyelia, or split cord malformation, a complete or incomplete sagittal division of the neural axis into halves, is seen in association with many other congenital anomalies. Among these anomalies, intradural spinal teratoma is extremely rare. Diastematomyelia is a well-recognized although unusual clinical syndrome in children, but it is rarely reported in the adult. The authors describe a 42-year-old man who presented with pain and distal left-leg weakness as well as neurogenic claudication for 1 month. The patient underwent radiological examinations, and diastematomyelia and an intradural lumbar teratoma were diagnosed. He underwent surgery and was followed for 1 year. This is the fourth case of an adult who simultaneously presented with diastematomyelia and an intradural teratoma.

Adult↗

PubMed2001

Determining optimal MRI follow-up after transsphenoidal surgery for pituitary adenoma: scan at 24 hours postsurgery provides reliable information.

There is no agreed-upon schedule for MRI follow-up after pituitary adenoma removal via the transsphenoidal approach. Our aim was to establish a plan for MRI follow-up after pituitary surgery. Eighty pituitary adenoma cases (25 microadenomas, 30 macroadenomas that did not infiltrate the cavernous sinus, and 25 macroadenomas with cavernous sinus infiltration) were prospectively studied with MRI following tumor resection via the transsphenoidal approach. Each patient was imaged at 24 hours, at 3, 6 and 9 months, and at 1 year or more postsurgery. The parameters studied were residual tumor, synthetic packing material (Gelfoam) versus fat graft, and normal pituitary, hypophyseal stalk and optic chiasma. The size of the pituitary structure as a whole was also measured. The latter was studied quantitatively, and the findings for the rest of the parameters were evaluated qualitatively, based on the examiners' confidence in their assessment. The final MRI study, done at least 1 year postsurgery in all cases, was considered the reference MRI for all scans. MRI performed 24 hours after surgery was diagnostically accurate for residual tumor and valuable for visualizing normal sellar structures. The findings also showed that fat packing takes longer to resorb than Gelfoam, but produces no potentially confounding contrast enhancement. An algorithm based on the results is presented for postsurgical MRI assessment of pituitary adenoma patients in which the scan at 24 hours postsurgery is the major factor that determines the timing of later rechecks.

Adenoma↗

PubMed2001

Value of transcranial Doppler ultrasonography in the diagnosis and follow-up of carotid-cavernous fistulae.

The introduction of transcranial Doppler ultrasonography (TCD) has made it possible to examine blood flow characteristics in carotid-cavernous sinus fistulae (CCSF) in a noninvasive, relatively simple, and reliable way. This study investigated the usefulness of TCD in the diagnosis and follow-up of various CCSF subtypes. We found characteristic TCD findings associated with high-flow CCSF, but perhaps more importantly, found this technique to be an excellent tool also for detecting and following treatment results in low-flow CCSF. The low-flow fistulae exhibit less specific clinical signs and are harder to distinguish using the noninvasive radiological methods of computed tomography (CT) and magnetic resonance imaging (MRI). The impact of our findings on future approaches to the diagnosis and follow-up of these different types of acquired vascular shunts is also discussed. The conclusions were as follows: a) TCD parameters (blood flow velocity and pulsatility index) for CCSF are specific, and are thus valuable in the hemodynamic assessment of these lesions. b) Since dural CCSF feature more subtle hemodynamic changes and CT and MRI findings may be normal, these cases pose diagnostic challenges. In these situations, TCD reveals specific diagnostic findings and allows the examiner to determine whether cerebral angiography is indicated.

Adolescent↗

PubMed2001

Spinal solitary fibrous tumor: seventh reported case and review of the literature.

We present the clinical, radiological, and pathological features of a solitary fibrous tumor in the spinal cord. This case is the seventh spinal solitary fibrous tumor in the literature. The tumor caused clinical symptoms in a 70-year-old female, which indicated compression of the spinal cord. Magnetic resonance imaging showed an intradural extramedullary mass at T3 vertebral level. Surgically, the tumor was firm, in an intradural extramedullary location and attached to the dura. Histologically, the tumor was composed of spindle cells in a collagen-rich matrix but exhibited regional variations. CD34 and vimentin were diffusely positive during immunohistochemical stain testing. The tumor displayed no positive staining for epithelial membrane antigen, cytokeratin, S-100 protein, smooth muscle actin or desmin. The Ki-67 labeling index was low. Solitary fibrous tumors have been found in a variety of locations suggesting that a solitary fibrous tumor has a mesenchymal origin. This rare tumor should be considered in the differential diagnosis of spinal tumors.

Aged↗

PubMed2001

Further cranial settling of the upper cervical spine following odontoidectomy. Report of two cases.

A variety of diseases may affect the craniovertebral junction and require a decompressive and fusion procedure. Craniovertebral junction instability is expected after a fusion procedure. The authors describe two patients with basilar invagination who underwent transoral odontoidectomy and occipitocervical fixation. Despite an uneventful immediate postoperative course, further cranial settling of the C-2 vertebral body (VB) was demonstrated. One patient experienced neurological deterioration and required a second decompressive procedure, whereas the second patient was asymptomatic and required no additional surgery. It was concluded that the odontoidectomy may have led to horizontal separation of the C-1 lateral masses, resulting in further cranial settling of the C-2 VB. Preservation of one aspect of the C-1 anterior arch minimizes C-1 lateral mass offset and, in turn, further cranial settling of the C-2 VB. In addition, a more rigid fixation of C-2 may minimize the possibility of horizontal separation of the C-1 lateral masses after transoral odontoidectomy.

Adult↗