Creating a neuroanatomy education model with augmented reality and virtual reality simulations of white matter tracts

OBJECTIVE

The utilization of digital technologies has experienced a notable surge, particularly in cases where access to cadavers is constrained, within the context of practical neuroanatomy training. This study evaluates augmented reality (AR)- and virtual reality (VR)-based educational models for neuroanatomy education.

METHODS

Three-dimensional models were created using advanced photogrammetry. VR- and AR-based educational models were developed by arranging these 3D models to align with the learning objectives of neurosurgery residents and second-year medical students whose cadaveric training was disrupted due to an earthquake in Turkey. Participants engaged with and evaluated the VR- and AR-based educational models, followed by the completion of a 20-item graded user experience survey. A 10-question mini-test was given to assess the baseline knowledge level prior to training and to measure the achievement of learning objectives after training.

RESULTS

Forty neurosurgery residents were trained with a VR-based educational model using VR headsets. An AR-based educational model was provided online to 200 second-year medical students for their practical neuroanatomy lesson. The average correct answer rates before the training were 7.5/10 for residents and 4.8/10 for students. These rates were significantly improved after the training to 9.7/10 for residents and to 8.7/10 for students (p < 0.001). Feedback from the users concurred that VR- and AR-based training could significantly enhance the learning experience in the field of neuroanatomy.

CONCLUSIONS

VR/AR-based educational models have the potential to improve education. VR/AR-based training systems can serve as an auxiliary tool in neuroanatomy training, offering a realistic alternative to traditional learning tools.

Endonasal endoscopic approach for sellar metastatic pathologies: a national observation

PURPOSE

Sellar metastases are rare lesions. Recent improvements in diagnosis and treatment strategies have prolonged survival but increased the probability of metastatic tumors. Evaluation with clinical symptomatology and meticulous laboratory examination is crucial. We present our multicenter national study on sellar metastases to evaluate and underline the main clinical, endocrine, and radiological considerations regarding the diagnosis and endonasal endoscopic management of such rare lesions.

METHODS

A medical literature-based retrospective study was planned across 13 neurosurgical centers in Turkey, where a data survey was conducted to collect information regarding sellar metastases surgically treated using the endoscopic endonasal approach, including clinical presentation, radiographic features, primary tumor origin, histopathological confirmation, time to metastasis, treatment, and patient outcomes.

RESULTS

Between 2010 and 2020, 54 patients (22 women [40.7%] and 32 men [59.3%]) who underwent surgery with the endonasal endoscopic approach and had pathologically proven sellar metastases (overall incidence, 0.54%) were included. Of the patients, 59.3% had no known malignancy and presented with new-onset symptoms, 79.6% reported headache, 51.9% complained of some degree of visual deficits, and 50% had cranial nerve symptoms. Tissue biopsy was performed in 7.4% of the patients, whereas gross or subtotal resection was achieved in the remaining patients.

CONCLUSION

To our knowledge, this is the largest series of patients surgically treated with the endonasal endoscopic approach for sellar metastases. For these patients, the treatment focus should be on management modalities for increasing quality of life instead radical treatment options with survival benefit.

Development and Validation of a Novel Methodological Pipeline to Integrate Neuroimaging and Photogrammetry for Immersive 3D Cadaveric Neurosurgical Simulation

Background

Visualizing and comprehending 3-dimensional (3D) neuroanatomy is challenging. Cadaver dissection is limited by low availability, high cost, and the need for specialized facilities. New technologies, including 3D rendering of neuroimaging, 3D pictures, and 3D videos, are filling this gap and facilitating learning, but they also have limitations. This proof-of-concept study explored the feasibility of combining the spatial accuracy of 3D reconstructed neuroimaging data with realistic texture and fine anatomical details from 3D photogrammetry to create high-fidelity cadaveric neurosurgical simulations.

Methods

Four fixed and injected cadaver heads underwent neuroimaging. To create 3D virtual models, surfaces were rendered using magnetic resonance imaging (MRI) and computed tomography (CT) scans, and segmented anatomical structures were created. A stepwise pterional craniotomy procedure was performed with synchronous neuronavigation and photogrammetry data collection. All points acquired in 3D navigational space were imported and registered in a 3D virtual model space. A novel machine learning-assisted monocular-depth estimation tool was used to create 3D reconstructions of 2-dimensional (2D) photographs. Depth maps were converted into 3D mesh geometry, which was merged with the 3D virtual model’s brain surface anatomy to test its accuracy. Quantitative measurements were used to validate the spatial accuracy of 3D reconstructions of different techniques.

Results

Successful multilayered 3D virtual models were created using volumetric neuroimaging data. The monocular-depth estimation technique created qualitatively accurate 3D representations of photographs. When 2 models were merged, 63% of surface maps were perfectly matched (mean [SD] deviation 0.7 ± 1.9 mm; range −7 to 7 mm). Maximal distortions were observed at the epicenter and toward the edges of the imaged surfaces. Virtual 3D models provided accurate virtual measurements (margin of error <1.5 mm) as validated by cross-measurements performed in a real-world setting.

Conclusion

The novel technique of co-registering neuroimaging and photogrammetry-based 3D models can (1) substantially supplement anatomical knowledge by adding detail and texture to 3D virtual models, (2) meaningfully improve the spatial accuracy of 3D photogrammetry, (3) allow for accurate quantitative measurements without the need for actual dissection, (4) digitalize the complete surface anatomy of a cadaver, and (5) be used in realistic surgical simulations to improve neurosurgical education.

Does Antimicrobial Stewardship Program Improve the Quality of Care in ICU Patients Consulted to Infectious Diseases? Experience in a Tertiary Care Hospital

BACKGROUND

One of the most important public health problems is the ever growing problem of antibiotic resistance. On one hand, the rate of introduction of new molecules into clinical practice has considerably slowed down, on the other hand, rapid emergence of resistance shortens the effective "life-span" of these molecules.

OBJECTIVE

In this study, the quality of care before and after active intervention and feedback was evaluated in patients diagnosed with sepsis/septic shock or ventilator-associated pneumonia (VAP) in Hacettepe University Adult and Oncology Hospitals ICUs.

RESULTS

There was a significant increase in total scores. Significant improvements were achieved in the management of these patients in terms of requesting necessary diagnostic tests, and prolonged infusion of beta-lactam agents.

CONCLUSION

Implementation of an ASP in centers where antimicrobial management of ICU patients is largely controlled by infectious diseases specialists is still a feasible strategy that leads to better patient care.

68Ga-DOTATATE PET/CT in Pituitary Carcinoma

ABSTRACT

A 47-year-old woman with atypical pituitary adenoma was referred to the neurosurgery department due to recent back pain. She had multiple transsphenoidal surgery, stereotactic body radiation, and 177Lu-DOTATATE therapy. Her spinal MRI showed multiple spinal masses. The patient underwent 68Ga-DOTATATE PET/CT to confirm the metastatic spread of the disease. PET/CT images showed increased uptake at the local recurrent tumor site and spinal metastases confirmed by biopsy to pituitary carcinoma. Our case presents the role of 68Ga-DOTATATE PET/CT in patients with pituitary carcinoma.

Qlone®: A Simple Method to Create 360-Degree Photogrammetry-Based 3-Dimensional Model of Cadaveric Specimens

BACKGROUND

Human cadavers are an essential component of anatomy education. However, access to cadaveric specimens and laboratory facilities is limited in most parts of the world. Hence, new innovative approaches and accessible technologies are much needed to enhance anatomy training.

OBJECTIVE

To provide a practical method for 3-dimensional (3D) visualization of cadaveric specimens to maximize the utility of these precious educational materials.

METHODS

Embalmed cadaveric specimens (cerebrum, brain stem, and cerebellum) were used. The 3D models of cadaveric specimens were built by merging multiple 2-dimensional photographs. Pictures were taken with standard mobile devices (smartphone and tablet). A photogrammetry program (Qlone®, 2017-2020, EyeCue Vision Technologies Ltd, Yokneam, Israel), an all-in-one 3D scanning and augmented reality technology, was then used to convert the images into an integrated 3D model.

RESULTS

High-resolution 360-degree 3D models of the cadaveric specimens were obtained. These models could be rotated and moved freely on different planes, and viewed from different angles with varying magnifications. Advanced editing options and the possibility for export to virtual- or augmented-reality simulation allowed for better visualization.

CONCLUSION

This inexpensive, simple, and accessible method for creating 360-degree 3D cadaveric models can enhance training in neuroanatomy and allow for a highly realistic surgical simulation environment for neurosurgeons worldwide.

Human–Robot Interfaces of the NeuRoboScope: A Minimally Invasive Endoscopic Pituitary Tumor Surgery Robotic Assistance System

Endoscopic endonasal surgery is a commonly practiced minimally invasive neurosurgical operation for the treatment of a wide range of skull base pathologies including pituitary tumors. A common shortcoming of this surgery is the necessity of a third hand when the endoscope has to be handled to allow active use of both hands of the main surgeon. The robot surgery assistant NeuRoboScope system has been developed to take over the endoscope from the main surgeon's hand while providing the surgeon with the necessary means of controlling the location and direction of the endoscope. One of the main novelties of the NeuRoboScope system is its human–robot interface designs which regulate and facilitate the interaction between the surgeon and the robot assistant. The human–robot interaction design of the NeuRoboScope system is investigated in two domains: direct physical interaction (DPI) and master–slave teleoperation (MST). The user study indicating the learning curve and ease of use of the MST is given and this paper is concluded via providing the reader with an outlook of possible new human–robot interfaces for the robot assisted surgery systems.

Role of Hypofractionated Stereotactic Radiosurgery in Recurrent Pineal Parenchymal Tumors of Intermediate Differentiation: A Case Report and Review of the Literature

A pineal parenchymal tumor of intermediate differentiation (PPID) is a rare entity, and optimal treatment is still unclear. Combined multimodality treatment should be considered in PPID due to high recurrence rates. Gross total resection is the first choice of treatment, however, it may not be feasible in every case due to location. Stereotactic radiosurgery (SRS) can be considered for the treatment of primary and recurrent disease, as it enables us to deliver a high radiation dose to the target while minimizing radiation exposure to normal tissue. In this report, we present a case treated with hypofractionated SRS for recurrent/metastatic PPID after the primary tumor was controlled with the combination of surgery and conventionally fractionated radiotherapy.

The Past, Present, and Future Statuses of Formerly Classified "Atypical Pituitary Adenomas": A Clinicopathological Assessment of 101 Cases in a Cohort of More than 1,000 Pure Endoscopically Treated Patients in Single Center

Objective  This study was aimed to assess the clinical aggressiveness of pituitary neoplasms that were previously defined as atypical adenomas. Methods  A total of 1,042 pituitary adenomas were included in the study and 101 of them were diagnosed as atypical adenoma. Demographic characteristics, radiological evaluations, and clinical information were obtained from a computer-based patient database. Cases were categorized as atypical or typical using the criteria listed in 2004 Classification of Tumors of Endocrine Organs. Results  The cure and reoperation rates did not show any statistically significant difference between the typical and atypical adenomas. However, a higher K _i -67 labeling index was found to be associated with a higher rate of reoperation ( p  = 0.008) in atypical adenomas. Of note, cavernous sinus invasion or parasellar extension was found to be associated with lower cure rates in patients with atypical pituitary adenomas ( p  < 0.001 and p  = 0.001, respectively). Conclusion  Although atypical pituitary adenomas are known to be more invasive, this study demonstrated that the reoperation and cure rates are the same for typical and atypical adenomas. Our findings advocate for omitting the use of atypical adenoma terminology based solely on pathological evaluation. As stated in the 4th edition of the World Health Organization (WHO) classification, accurate tumor subtyping, evaluation of proliferation by means of mitotic count and K _i -67 labeling index, and radiological and intraoperative assessments of tumor invasion should be taken into consideration in the management of such neoplasms.

The Effect of Training, Used-Hand, and Experience on Endoscopic Surgery Skills in an Educational Computer-Based Simulation Environment (ECE) for Endoneurosurgery Training

Today, virtual simulation environments create alternative hands-on practice opportunities for surgical training. In order to increase the potential benefits of such environments, it is critical to understand the factors that influence them. This study was conducted to determine the effects of training, used-hand, and experience, as well as the interactions between these variables, on endoscopic surgery skills in an educational computer-based surgical simulation environment. A 2-hour computer-based endoneurosurgery simulation training module was developed for this study. Thirty-one novice- and intermediate-level resident surgeons from the departments of neurosurgery and ear, nose, and throat participated in this experimental study. The results suggest that a 2-hour training during a 2-month period through computer-based simulation environment improves the surgical skills of the residents in both-hand tasks, which is necessary for endoscopic surgical procedures but not in dominant hand tasks. Based on the results of this study, it can be concluded that computer-based simulation environments potentially improve surgical skills; however, the scenarios for such training modules need to consider especially the bimanual coordination of hands and should be regularly adapted to the individual skill levels and progresses.

Technology-enhanced surgical education: attitudes and perceptions of the endoscopic surgery community in Turkey

The education programme of surgery has unique problems. In this study, first, a literature review is conducted to cover the studies found in the literature reporting on the problems of surgical education. Additionally, a survey study is conducted with 31 participants, who are either currently enrolled in endoscopic surgery education programmes in Turkey or are experts in the field. Supportively semistructured individual interviews are also conducted with five participants. These data are collected to better understand the instructional methods being used, their problems and the participants’ preferred methods to be used. Additionally, the participants’ attitudes are also investigated regarding the use of new technologies to enhance the current education programmes. The results indicate that, in Turkey, surgical education programmes are still mostly offered in traditional ways while other educational methods are used in an extremely limited manner. In general, the authors emphasise that more research needs to be conducted to better understand the characteristics of the medical students and develop standards for surgical education programmes, educational tools specific for related surgical domains and guidelines for the curriculum integration. The results of this study aimed to guide the instructional system designers for the endoscopic surgery education programmes.

Reasons and results of endoscopic surgery for prolactinomas: 142 surgical cases

BACKGROUND

We report herein a retrospective analysis of the results of 142 consecutive prolactinoma cases operated upon using an endoscopic endonasal trans-sphenoidal approach over a period of 6 years.

METHODS

Medical records of 142 cases were analysed with respect to indications for surgery, duration of hospital stay, early remission rates, failures and recurrence rates during a median follow-up of 36 months.

RESULTS

On the basis of magnetic resonance imaging (MRI) data, 19 patients (13.4 %) had microadenoma, 113 (79.6 %) had macroadenoma, and the remaining 10 (7.0 %) had giant adenomas. Cavernous sinus invasion was identified in 25 patients by MRI and confirmed during surgery. Atypical adenoma was diagnosed in 16 patients. Sparsely granulated prolactin adenoma was identified in 99 patients (69.7 %). Our results demonstrate that male sex and higher preoperative prolactin levels are independent factors predicting persistent disease. The post-surgical complications are as follows: 2.8 % patients had meningitis, 2.1 % patients had postoperative cerebrospinal fluid leak and 2.1 % patients had panhypopituitarism. At the end of follow-up, 74.6 % patients went into remission. During follow-up period, five patients who had initial remission developed recurrence.

CONCLUSIONS

Our series together with literature data suggest that an endoscopic endonasal trans-sphenoidal approach in the treatment of proloctinomas has a favourable rate of remission. According to the findings of this study, endoscopic endonasal trans-sphenoidal surgery might be an appropriate therapy choice for patients with prolactinoma who could not have been managed with recommended therapeutic modalities.

Splitting of the Optic Nerve by a Pituitary Macroadenoma

BACKGROUND

Splitting of the optic nerve by a pituitary adenoma is an extremely unusual condition with only 3 cases reported to date.

CASE DESCRIPTION

A 41-year-old woman presented with visual loss as a result of an aggressive pituitary macroadenoma causing the splitting of the right optic nerve. Possible mechanisms of this condition are discussed, and the literature is reviewed.

CONCLUSIONS

In aneurysm and tumor cases, awareness of the exact anatomy is particularly important to preserve function. An overlooked duplication or penetration of cranial nerves may result in inadvertent injury to important structures and loss of function.

Treatment of acromegaly by endoscopic transsphenoidal surgery: surgical experience in 214 cases and cure rates according to current consensus criteria

Object

Acromegaly is a disease that has significant morbidity and mortality related to high levels of growth hormone (GH) and insulin-like growth factor–I (IGF-I), and is usually caused by pituitary adenomas. The goal in this study was to investigate the role of endoscopic transsphenoidal surgery and surgical experience in the treatment of GH adenoma cases in relation to surgical results and hormonal cure rates, and to perform a review of the literature.

Methods

The authors present a retrospective analysis of 214 GH adenoma cases. Restoration of IGF-I levels to normal for age and sex, suppression of GH levels below 0.4 μg/L on the oral glucose tolerance test, and demonstration of the total removal of the tumor on MRI studies obtained after administration of contrast material at the 3-month postoperative follow-up visit were the criteria for cure.

Results

In total 214 patients with a mean age of 41.9 ± 12 years (range 17–75 years) and a male/female ratio of 106/108 were enrolled in the study. Cure was achieved in 134 (62.6%) of 214 patients. One hundred sixty-nine patients were primary cases, and of these 109 (64.5%) were cured, whereas 61 patients were previously operated cases and of these 25 (41%) were cured. With a 51.1% decrease in the 1st month postoperatively, IGF-I levels were found to be predictive of cure (74.4% sensitivity and 73.7% specificity). Cut-off values for GH levels in predicting cure for the 1st day, 1st week, and 1st month postoperatively were 2.33, 2.05, and 2.25 μg/L, respectively.

The cut-off value for surgical experience was 57 for primary surgeries (58.5% cure rate before this cut-off value compared with 72.6% after it; p = 0.025) and 108 for all operations (45.8% vs 79.4%, p = 0.037). Although 28 patients were found to be in remission according to the criteria in 2000, they were not in remission according to the new consensus criteria. Nine of these cases (32.1%) had random GH levels < 1 μg/L at the 1-year follow-up. The 1-year IGF-I and GH levels in these 28 patients showed no significant difference when compared with the cases defined as cured according to the current criteria.

Conclusions

In acromegaly treatment, transsphenoidal endoscopic surgery performed by an expert senior surgeon and increased surgical experience are important for higher cure rates. Random GH levels < 2.33 μg/L after the 1st day postoperatively and a > 50% decrease in IGF-I levels after the 1st month postoperatively are predictive of cure. Moreover, there is no urgency for additional therapy in patients with GH levels of 0.4–1 μg/L and MRI sequences showing no tumor at the 3-month follow-up, because for these cases remission can be achieved at the 1-year follow-up.

Early promising results for the endoscopic surgical treatment of Cushing's disease

High levels of endogenous cortisol due to Cushing's disease cause significant mortality and morbidity. Treatment of Cushing's disease is challenging. For many years, transsphenoidal microsurgical resection of the adenoma has been the treatment of choice. However, recently, neuroendoscope has taken its place in the neurosurgeon's armamentarium, and the endoscopic transsphenoidal resection of pituitary tumors has become a familiar approach. Our aim was to present the results of pure endoscopic surgery in the treatment of corticotropinomas for comparison with the results of previous endoscopic and microsurgical series. We present a retrospective analysis of 90 patients with diagnosis of Cushing's disease who were operated between 2006 and 2012. Among 90 patients, a total of 81 (90.0 %) had a remission (28 out of 29 macroadenomas (96.6 %) and 53 out of 61 microadenoma patients (86.9 %)). Of note is that 66 out of 69 (95.7 %) primary patients (i.e., those who were operated in our center) and 15 out of 21 (71.4 %) patients previously operated in other centers reached a hypo/eucortisolemic state. A remission rate comparable with previous endoscopic series was achieved. In nine patients, it was not possible to achieve remission at all. On the other hand, only four of our cases (5.6 %) had a recurrence, and with reoperation, all of these patients entered a re-remission. To our knowledge, our series is the largest series studying endoscopically operated adrenocorticotropic hormone-secreting adenomas. Our results suggest that the endoscopic approach has opened a new avenue in the treatment of Cushing's disease, previously a therapeutic challenge for both the clinician and the neurosurgeon. Endoscopic approach in the treatment of Cushing's disease is clearly better for patients because of its low morbidity rates and short duration of hospital stay. On the other hand, long-term follow-up of our patients will show whether these favorable observations will persist.

Thyrotropinoma and multinodular goiter: A diagnostic challenge for hyperthyroidism

Thyroid disorders are frequently encountered. The diagnosis is straightforward unless clinical or laboratory findings are inconclusive and/or perplexing. Hyperthyroidism due to a thyrotropin-secreting pituitary adenoma rarely occurs and symptoms due to thyroid hormone excess are subtle. The presentation of the disease becomes unusual when co-secretion of other hormones with thyrotropin or concomitant thyroid parenchymal pathology exist. We present the case of a 63-year-old female patient with thyrotropinoma co-secreting growth hormone and multinodular goiter. She developed hyperthyroidism first due to thyrotropinoma and later due to a toxic nodule. Herein, we discuss the diagnostic and therapeutic challenges of hyperthyroidism with atypical presentation.

Complications of endoscopic surgery of the pituitary adenomas: analysis of 570 patients and review of the literature

Endoscopic transsphenoidal surgery is emerging as a minimally invasive and maximally effective procedure for pituitary adenomas. In this report we analyzed the complications in 624 procedures of endonasal transsphenoidal endoscopic surgery in the treatment of 570 patients with pituitary adenomas. The leading author (MB) operated pituitary adenomas via pure endoscopic endonasal transsphenoidal surgery between January 2006 and August 2011 at the Hacettepe University, Department of Neurosurgery in Ankara. Complications were assessed in 624 surgical procedures under five groups; rhinological, CSF leaks, infection, vascular and endocrinologic complications. We observed a total of 76 complications (12.1%). Rhinological complications occurred in 8 patients (1.3%): 4 epistaxis (0.6%) and 4 hyposmia (0.6%). Postoperative CSF leaks occurred in 8 patients (1.3%), and infectious complications occurred in 8 patients: 3 cases of sphenoidal sinusitis (0.4%), 5 cases of meningitis (0.8%). Only 1 case of internal carotid aneurysm rupture during the opening of sellar floor (0.16%) was observed. Endocrinologic complications occurred in 51 (8.1%) patients: Anterior pituitary deficiency in 12 (1.9%), transient diabetes insipidus (DI) in 29 (4.6%), permanent DI in 3 (0.4%) and inappropriate antidiuretic hormone secretion syndrome occurred in 7 (1.1%). There was no mortality directly related to the surgical procedure. The complication rates observed in our study suggests that the endoscopic pituitary surgery is at least as safe as microscopic transphenoidal surgery. These rates were obtained with due experience and well-coordinated teamwork. To further improve these rates, new technological developments will be helpful.

A case of intracranial hypotension complicated with hydrocephalus

AIM

Intracranial hypotension may have variable clinical presentation. The imaging characteristics of intracranial hypotension are especially well depicted on magnetic resonance imaging studies. Although the clinical and radiological manifestations of spontaneous intracranial hypotension are increasingly recognized in many reports, many other abnormalities in this disorder and complicating cases still exist.

MATERIAL AND METHODS

A 16-year-old patient suffering from nausea vomiting and blurred consciousness was admitted to the hospital. MRI showed diffuse pachymeningeal thickening resembling intracranial hypotension and ventricular enlargement like compensated hydrocephalus. The patient was investigated and treated using endoscopic third ventriculostomy.

CONCLUSION

The authors presented a case of intracranial hypotension complicated with hydrocephalus. Specific causes for intracranial hypotension as well as additional new treatment options will also be discussed.

Overview of vascular complications of pituitary surgery with special emphasis on unexpected abnormality

Arterial bleeding during transsphenoidal surgery for pituitary adenoma is known complication. This usually happens due to rupture of intracavernous carotid or delayed hemorrhage due to the carotico-cavernous fistula and/or pseudoaneurysm. There is also evidence that cavernous carotid aneurysms may occur with pituitary tumors, yet largest series failed to demonstrate any link between aneurysm formation and pituitary tumors. Usually such an aneurysm rupture results in formation of carotico-cavernous fistula. However, pituitary apoplexy and even epistaxis have been reported. In this paper we present a patient with recurrent pituitary adenoma and cavernous carotid artery aneurysm, which caused significant hemorrhage during the surgery. Although retrospective analysis of MRI disclosed that the patient had the aneurysm before the first surgery, it remained silent until the second operation. Therefore neurosurgeons should be very susceptive to any signal changes on preoperative MR images, especially in recurrent cases, where normal anatomical relations are disturbed by fibrotic tissue. Also, we reviewed the vascular complication of pituitary surgery based on the literature.

Microscopic and electrophysiological changes on regenerating sciatic nerves of rats treated with simvastatin

Simvastatin is a hypocholesterolemic agent presumed to cause peripheral neuropathy. We arranged an experimental design which focuses on the effect of simvastatin on peripheral nerves and neural regeneration. Sciatic nerve injury was performed at midthigh region of male wistar rats either by clamp compression or fine cut. Electrophysiological and electron microscopical studies were carried out to assess the effect of simvastatin on peripheral nerve and nerve regeneration. There was no difference between the groups that were given simvastatin and standard regimen in the sciatic nerve when electrophysiological measurements were concerned. However, some of the rats that were given simvastatin show reduction in axoplasm density (intensity) of myelinated nerve fibers and prominent vacuolization of myelin sheath according to light and electron microscopic studies. Sciatic nerve compound muscle activation potential measurements of the animals given simvastatin showed that this drug doesn't have a delaying effect on the peripheral nerve recovery time. Electrophysiological measurements showed that simvastatin did not influence nerve regeneration however it was found to induce severe vacuolization of myelin sheath of the sciatic nerve. It was apparent that the drug induces some form of structural dysfunction as myelin changes supported by electron microscopical studies.

CONCLUSION

simvastatin was shown to delay regeneration as shown in microscopic studies but still there was no influence on nerve regeneration.

A case of acromegaly in pregnancy: Concomitant transsphenoidal adenomectomy and cesarean section

The case of a 32-year-old woman at 29 weeks gestational age with acromegaly initially diagnosed in pregnancy is presented. During follow-up at 34 weeks of gestation, concomitant emergency cesarean section and transsphenoidal surgery were performed because of advancing vision loss. In tertiary centers, success in pregnancy can be made possible for a patient with acromegaly under the constant supervision of an obstetrician and neurosurgeon.

Somatotropin adenoma and resistance to thyroid hormone

Resistance to thyroid hormone (RTH) is a rare disease characterized by non-suppressed TSH in spite of high free thyroid hormone levels. Up to date, in the literature, there are more than 600 RTH cases, but co-incidental hypophyseal adenoma was reported in only 1 case. In the literature, despite reported cases with thyrotropinoma accompanying RTH, we could not find a case with somatotropinoma accompanying RTH. Here, we report a 34-yr-old male patient, who was admitted to the hospital with complaints of dyspnea, chest pain, and palpitation in 2003. His alpha- subunit value was normal and the alpha-subunit/TSH molar ratio was <1. His response to TRH stimulation test was normal. His TSH level was suppressed in the T3 suppression test. Hypophyseal magnetic resonance imaging showed a 6-mm hypophyseal microadenoma. Levels of all anterior hypophyseal hormones, including GH and IGF-I, were normal. Oral glucose tolerance test (OGTT)-GH suppression test was normal. The patient was followed with the diagnosis of RTH and incidental hypophyseal adenoma. After 3 yr, because of high levels of IGF-I: 901 ng/ml (68-324), the OGTT-GH suppression test was reported and no suppression was detected. Thus, the patient was referred to surgery with the pre-diagnosis of RTH and acromegaly. Immunohistochemistry was showed as strong GH staining with low Ki 67 index while TSH and other anterior hypophyseal hormones stainings were negative. Post-operative thyroid hormones were still high.

Intracranial Haemorrhage Probably Due to an Angiographically Occult AVM after Carotid Stenting. A Case Report

SUMMARY

Angiographically occult vascular malformations refer to cerebrovascular malformations that are not demonstrable on technically satisfactory cerebral angiography. Authors herein present a very unusual intracranial bleeding complication related to an angiographically occult vascular malformation after extracranial carotid artery stenting procedure. A 52-year-old male patient admitted to the hospital with 2 episodes of amaurosis fugax in the left eye. Cervical carotid angiography and bilateral carotid Doppler ultrasonography revealed a 98% stenosis of the left internal carotid artery just distal to the bifurcation. Post-stenting control cervical carotid angiography revealed neither any residual stenosis nor a developmental venous anomaly. The patient developed left pupil dilatation with loss of consciousness two hours after the neurovascular intervention. Emergent cranial CT showed acute subdural haematoma, intracerebral and subarachnoid haemorrhage with massive midline shift. He underwent an emergent craniotomy with left temporal lobectomy. Abnormal cortical vascular structures with prominent engorgement were remarkable over the posterior temporal cortex. Histopathological studies confirmed the diagnosis of an occult AVM. Classically, these lesions are not visualized with angiography.Our patient's cerebral angiography and MR investigations were all normal. To our knowledge this is the first case in literature in which intracranial haemorrhage (acute subdural haematoma, intracerebral haematoma, SAH) occurred due to hyperperfusion of angiographically occult vascular malformation.

A giant intramedullary spinal epidermoid cyst of the cervicothoracic region

Intramedullary epidermoid cysts of the spinal cord are rare lesions. The authors report a case of giant intramedullary epidermoid cyst at the cervicothoracic region. A 6-year-old boy presented with motor and sensory loss related to a spinal intramedullary epidermoid cyst. Almost all cyst content was liquid and it was surgically removed totally in two successive operations. To the author's knowledge, this is the largest intramedullary epidermoid cyst published in the literature and no other case of intramedullary epidermoid cyst with a complete liquid content has been reported before. The authors discuss the clinical features, MR imaging characteristics and surgical findings of this rare tumor and review the associated literature.

Traumatic epidural haematoma of the posterior fossa in childhood: 16 new cases and a review of the literature

A series of 16 children (nine males, seven females) with traumatic epidural haematoma of the posterior fossa (TEHPF) is presented. All patients had a history of mild to moderate trauma to the occiput. The causes were falls in 15 and traffic accident in one case. Four of the 16 cases had depressed fractures of the occipital bone. Surgical intervention was performed in all cases. In 14 patients the outcome was good, one patient had moderate disability and one died. Our study revealed that early diagnosis and urgent surgical intervention may give the patient a chance of total recovery and craniotomy with haematoma evacuation is an appropriate surgical technique as in the case of supratentorial extradural hematoma.

Hemorheology, melatonin and pinealectomy. What's the relationship? An experimental study

The circadian rhythm of stroke and myocardial infarction (MI) may be related to the circadian rhythm of melatonin, and erythrocyte deformability may be the key mechanism in this relationship. Therefore, this study has been performed to determine if there is a relationship between the pineal gland and melatonin and red cell deformability. Twenty-eight rats underwent pinealectomy, pinealectomy plus melatonin administration (200 mg/kg), or no treatment (n=7 in each group). Erythrocyte deformability was determined using the filtration technique. The results are reported in mean (+/-SD) seconds: control: 1.45+/-0.44; pinealectomy (A): 1.55+/-0.16; pinealectomy (B): 1.34+/-0.26 and pinealectomy and melatonin: 2.56+/-0.69. Pinealectomy by itself did not cause any statistically significant change in erythrocyte deformability but the addition of melatonin significantly decreased it. These results suggest a relationship between melatonin and erythrocyte deformability. Further investigations may uncover the causes of the circadian rhythm of stroke and MI, which may help improve chronobiological therapies.

Acute Parotitis Following Sitting Position Neurosurgical Procedures

Acute bacterial parotitis subsequent to major abdominal surgery is well documented, reportedly occurring in as many as 0.1% of patients. Postoperative parotitis has been reported between 1 to 15 weeks after surgery, commonly appearing within 2 weeks of the procedure. However, postoperative parotitis has not been reported previously after neurosurgical procedures. The authors report five cases of postoperative parotitis after neurosurgical operations in the sitting position with mild flexion and rotation of the head. This group of patients accounted for 0.16% of all craniotomy and 1.9% of all sitting position neurosurgical procedures performed in the authors' institution from 1996 through 2001. Neck flexion and head tilt in the sitting position might have an influence on acute parotitis. The authors found that the side of the parotitis was on the opposite side of the head rotation. Dehydration therapy may also be a contributing factor. The objective of this paper is to state that parotitis is a possible complication in neurosurgical patients operated on in sitting position and to discuss its pathophysiology and treatment options.

Ultra rapid spontaneous resolution of acute posttraumatic subdural hematomas in patient with temporal linear fracture

We report a case of 57 year-old man with documented posttraumatic acute subdural hematoma and a linear temporal bone fracture. He suffered from a blunt head injury and presented with sudden loss of consciousness. Within 2 hours he became alert and oriented. Follow-up CT scan of brain 2 hours after the initial one showed resolution and redistribution of the subdural hematoma. To our knowledge, this is the first case in the literature about spontaneous resolution of an acute subdural hematoma in a patient with a linear fracture and the fastest resolution period. In this article, the authors discuss the underlying pathophysiology of this uncommon phenomenon.

Neuronal Nuclear Antigen (NeuN): A New Tool in the Diagnosis of Central Neurocytoma

The use of neuronal nuclear antigen (NeuN) as a reliable neuronal marker in the differential diagnosis of clear cell neoplasms of the central nervous system was determined in a biopsy series of 23 cases. Immunohistochemical analyses were carried out by antisera against neuronal nuclear antigen, synaptophysin, neuron-specific enolase, microtubule-associated protein 2, and glial fibrillary acidic protein. All eight central neurocytomas were characteristically immunolabeled by NeuN. NeuN immunoreactivity was uniformly strong and basically located in the nuclei of neurocytes. Despite this uniform staining pattern of central neurocytomas, 12 cases of oligodendrogliomas and three cases of ependymoma were negative for NeuN. As the diagnostic criteria for central neurocytoma include immunohistochemical and/or ultrastructural evidence for neuronal differentiation, NeuN as a sensitive and specific neuronal marker in formalin-fixed, paraffin-embedded tissues may greatly facilitate the differential diagnosis of central neurocytomas.

Endovascular treatment of kissing aneurysms at the fenestrated basilar artery. Case report with literature review

BACKGROUND

Basilar artery fenestrations are most commonly located in the proximal basilar trunk close to the vertebrobasilar junction and may harbor saccular aneurysms. Surgical treatment of such aneurysms has been reported in several cases previously, despite the difficulty of the surgical approach. Endovascular treatment may provide a more convenient treatment alternative in such cases. This case is also interesting in that two discrete aneurysms arise from each limb of the fenestration.

CASE REPORT

A 20-year-old man presented with acute subarachnoid hemorrhage. He had two kissing aneurysms at the fenestrated proximal basilar artery as demonstrated by MRA and selective angiography. The two aneurysms were successfully treated with GDCs via the contralateral vertebral arteries. One-year control angiogram showed stable occlusion.

CONCLUSION

Aneurysms at the fenestrated basilar artery may be effectively treated with endovascular coil occlusion. The occurrence of multiplicity and the treatment alternatives are discussed, with relevant literature review.

Cervical tuberculous spondylitis associated with systemic lupus erythematosus

STUDY DESIGN

A case report of cervical tuberculous spondylitis associated with systemic lupus erythematosus (SLE). Infection is a frequent problem in SLE, especially in patients hospitalised with the complications of the disease. Tuberculous spondylitis very rarely occurs in SLE patients, and cervical involvement has not been previously reported.

CASE REPORT

A 54-year-old female patient was admitted to our hospital with a complaint of neck pain radiating to her shoulder of 2 months' duration. The neurological examination was completely normal and radiological investigations revealed narrowing, angulation and destruction of the end plates of the 5th and 6th cervical vertebrae. She has received corticosteroid and colchicine treatment for the diagnosis of SLE during the last 10 years. The anterior cervical approach was used and pyogenic material was debrided from the C5-6 intervertebral space, and an otogenous bone graft with a Smith Robinson type fusion was performed.

CONCLUSION

High doses of corticosteroids are implicated as a risk factor for infection in SLE patients. Early diagnosis and appropriate medical and surgical treatment, as well as increased awareness of higher susceptibility to opportunistic infections, such as tuberculous spondylitis, are keystones for decreasing morbidity and mortality in patients with SLE.

Intraradicular disc herniations in the lumbar spine and a new classification of intradural disc herniations

STUDY DESIGN

A case report of intraradicular disc herniation. Intraradicular disc herniation is a special type of intradural disc herniations. In this report, we present the tenth case of intraradicular lumbar disc herniation and suggest a new classification for intradural disc herniations.

CASE REPORT

A 32-year-old male was admitted to hospital having experienced pain in the lower back and right leg for 1 month prior to admission. Neurological examination revealed weakness of the extensor hallucis longus, positive Laségue's sign, decreased ankle reflex in his right lower extremity, and bilateral paravertebral muscle spasm. Magnetic resonance imaging (MRI) revealed a disc herniation with a posterolateral extruded fragment on the right at the level of the L5-S1 space. He underwent L5 laminectomy. During the operation, the right S1 root was found to be swollen and immobile. A longitudinal incision was made in the dura of the right S1 root and an intradural free disc fragment was removed, and the S1 root was relieved. The patient was free of pain postoperatively.

CONCLUSION

We suggest a new classification for intradural disc herniations with this unusual case presentation and review the literature for pathogenesis, clinical picture, diagnosis and treatment.

Parafalcine chondrosarcoma: an unusual localization for a classical variant. Case report and review of the literature

BACKGROUND

Intracranial chondroid tumors are infrequently seen in neurosurgical practice. These tumors usually arise from cartilaginous synchondroses at the base of the skull, but occasionally from the pluripotential mesenchymal cells of the meninges. We present here a case of classic low-grade giant chondrosarcoma of the falx cerebri. This is only the second case of this variant reported in this location, and we summarize the diagnostic criteria with a brief review of literature.

CASE REPORT

A 56-year-old female patient was admitted to the hospital with a history of progressive right-sided weakness occurring in the last 8 months and a recent grand mal seizure. Radiological evaluation demonstrated a large extra-axial mass in the left parafalcine area, suggesting a possible meningioma. An anterior interhemispheric approach enabled gross total removal of the tumor and a histologic diagnosis of a low-grade classic chondrosarcoma was made. The patient is currently stable and has shown no evidence of recurrence in more than 3 years without any adjuvant treatment.

CONCLUSIONS

Intracranial cartilaginous tumors include classical, mesenchymal and myxoid chondrosarcomas in addition to benign chondromas. Parafalcine localization should be considered for all these variants as well as for meningiomas, hemangiopericytomas, solitary fibrous tumors, and meningeal metastatic carcinomas. Detailed radiological evaluation, light microscopic and ultrastructural analyses, and immunocytochemistry are essential for correct diagnosis. In contrast to mesenchymal and myxoid types, the prognosis of classic variants is usually good and does not require adjuvant treatment modalities if a radical resection of the tumor can be obtained. Increased documentation of clinical, radiological, and histologic findings as well as response to treatment modalities will provide a better understanding of the pathophysiology of these rare tumors, and highlight the optimum treatment strategies

Neurocutaneous melanosis associated with Dandy-Walker malformation. case report and review of the literature

Neurocutaneous melanosis is a rare dysmorphogenesis associated with single or multiple giant pigmented cutaneous nevi and diffuse involvement of the leptomeninges anywhere in the central nervous system (CNS). It is interesting that almost 8-10% of patients had associated Dandy-Walker malformation in the literature, suggesting a common origin of the developmental abnormalities. In this article, we present a 2-year-old patient with neurocutaneous melanosis associated with Dandy-Walker malformation. We reviewed the literature and discuss the pathogenesis based on the preferred hypotheses so far.

The effect of pinealectomy and foetal pineal transplantation of collagen ageing in rats

Recent progress in pineal research emphasized the importance of this circumventricular organ in the phenomenon of ageing as well. The present study was undertaken to elucidate the effects of pineal gland on collagen ageing by spectrofluorometrically measuring collagen-cross-link bound fluorescein. Experiments were performed on three different age groups of rats (3-4 weeks, 8-10 weeks, 15 and more weeks). Fluorescein values were found to increase causally by age in the control group. Eight weeks after sham operation of all the groups fluorescein level increments were shown to be parallel with the values of normal physiological ageing values. In experimental groups; in 3-5 weeks old rats pinealectomy produced a significant premature collagen ageing and this was found to be completely reversed by foetal pineal gland transplantation, but the reversal was limited to a sham operation level. On the other hand although a premature collagen ageing was found to be induced 8 weeks after pinealectomy in 8-10 weeks old rats with a statistical significance both within subject values and between sham operation and pinealectomy, foetal pineal gland transplantation was found not to reverse the premature ageing induced by pinealectomy. In 15 weeks old and older groups of rats, pinealectomy was found to facilitate the intrinsic ageing phenomenon of collagen with statistical significance again both within subject values and between sham operation and pinealectomy. Foetal pineal gland transplantation was not performed in this age group of rats. On interpretation of the data of pinealectomy against sham operation for all the age groups, the maximum degree of percentage increase in collagen-cross-link bound fluorescein was found in 3-5 weeks old rats (%218). The percentage increase in fluorescein values was found to be %170 and %126 in 8-10 weeks old and 15 weeks old and older rat groups, respectively. Consequently, we have experimentally shown the induction of collagen ageing by pinealectomy and the restorative competence of foetal pineal gland transplantation in the present study. The results seem to be impressive and details of the ageing process are the subject of further research.

Endoscopic evacuation of sacral hydatid cysts: case report

A case of hydatid disease of the intra and parasacral area is reported. This rare localization was probably due to previous abdominal hydatid cyst surgery. The patient underwent surgery, with a small opening in the SI lamina and the cysts were removed totally with the aid of a rigid endoscope. The surgical technique used and MRI findings are discussed.

The effect of the pineal gland on liver regeneration in rats

BACKGROUND/AIMS

We investigated the influence of pinealectomy on liver regeneration after partial hepatectomy in rats.

METHODS

Thirty rats were allocated into four groups as follows: group 1 in which no operation was done (control), group 2 in which only midline scalp incision and craniotomy was performed (sham operation), group 3 in which pinealectomy was performed and group 4 in which the rats underwent pinealectomy and pineal transplantation. Eight weeks later all the rats underwent 70% hepatectomy.

RESULTS

Hepatic regenerative capacity was observed 24 h after PH by bromodeoxyuridine incorporation into DNA and the mitotic index of hepatocytes. The bromodeoxyuridine labeling indices were 45.4, 35.8, 19.9 and 36.8 in groups 1, 2, 3 and 4, respectively. The mitotic indices of the same groups were 31.2, 28.7, 8.3 and 13.4, respectively. Both the bromodeoxyuridine labeling and mitotic indices were significantly lower in the pinealectomized rats than in the control and sham operation groups.

CONCLUSIONS

These results suggest that the pineal gland stimulates liver regeneration after partial hepatectomy in rats.

Pulmonary embolism in neurosurgical patients

BACKGROUND

Pulmonary embolism continues to be a frequent cause of morbidity and mortality in neurosurgical practice. This study was designed to investigate the presence of signs and/or symptoms helpful for an early diagnosis of pulmonary embolism and to evaluate the safety of heparin treatment in neurosurgical patients.

METHOD

We retrospectively reviewed 37 patients with pulmonary embolism among 6081 operated patients within the past 8 years at the Department of Neurosurgery, University of Hacettepe.

RESULTS

The overall incidence of pulmonary embolism was 0.42% and the mortality rate was 59.4%. The patients with cerebrovascular lesions had a significantly higher risk of pulmonary embolism compared with other neurosurgical pathologies. All patients were treated with heparin and subsequent oral warfarin therapy. None had intracranial or intraspinal bleeding while receiving anticoagulant therapy.

CONCLUSIONS

This study demonstrates that pulmonary embolism has a high mortality rate and heparin therapy can be used safely and without fear of intracranial or intraspinal bleeding.

Brucellosis of the spine

The spinal form of brucellosis is still a disabling disease in many countries outside North America and northern and central Europe. Fifteen consecutive cases of spinal brucellosis diagnosed and treated over a 20-year period were reviewed retrospectively. Six patients were farmers, while 10 patients had a history of ingestion of unpasteurized milk or other dairy products. A high index of suspicion is necessary for the diagnosis, since there are no pathognomonic signs or symptoms. Radiological assessment of the disease was reviewed and highlights in the differential diagnoses were stressed. The diagnosis was based on actual culture of Brucella bacilli in seven patients. The principal treatment of brucellosis of the spine is conservative, namely, immobilization and antimicrobial therapy. We have found both a combination of ofloxacin and rifampin and ofloxacin monotherapy efficient as the early regimens used in this series. Three patients had to undergo surgery, since a diagnosis could not be made in any other way.

Status epilepticus following iohexol myelography

Iohexol, a contrast medium widely used for myelography, has rarely been reported to cause convulsive disorders. A case of status epilepticus resulting from iohexol myelography is reported and problems of treatment are discussed.