Lateral transorbital approach: an alternative microsurgical route for supratentorial cerebral aneurysms.

OBJECTIVE: Transorbital approaches for neurosurgery have recently attracted attention and several anatomical studies have aimed to improve these techniques, but significant deficiencies in clinical practice remain, especially for aneurysm surgery. The authors present an alternative microsurgical route and the results of an analysis of patients with intracranial aneurysms who underwent a lateral transorbital approach (LTOA) using lateral orbito-zygoma-sphenotomy (LOZYGS). METHODS: The clinical and surgical results of a series of 54 consecutive patients with 1 or more aneurysms who underwent surgery via LTOA are reported. A lateral orbitotomy was performed after making a 3-cm skin incision parallel to the lateral orbital rim. A second bone flap, which included the zygoma and sphenoid bones that form the lateral orbital wall, was removed. The lesser sphenoid wing, including the anterior clinoid process, was fully drilled, except in cases of middle cerebral artery (MCA) aneurysms. Cisternal dissection was performed using the classic microsurgical technique starting from the proximal Sylvian fissure and carotid cistern. After the aneurysm was clipped following microsurgical principles, the dura mater was closed in a watertight fashion and 2-piece bone reconstruction was achieved. RESULTS: Sixty aneurysms in 54 patients were clipped using the LOZYGS route. Twenty-one aneurysms were located on the MCA, 30 on the anterior communicating artery, 8 on the internal carotid artery, and 1 at the apex of the basilar artery. The unruptured-to-ruptured aneurysm ratio was 17:43. The operative field was moved to the orbit using the LTOA to avoid interference by bone and muscle tissues. Early proximal control was achieved using a short working distance and direct exposure of the base of the cerebrum, without any requirement for retraction. Because different view angles and surgical corridors were used, no segment of the aneurysm or the parent artery remained unexposed. Therefore, the introduction of additional tools was not required. CONCLUSIONS: The LTOA allowed enhanced broad-perspective exposure of the operative field, early proximal control, and satisfactory surgical freedom. This alternative surgical approach safely exposed the target area and the operative field. The LOZYGS route is safe and effective for the LTOA and microsurgical clipping of anterior circulation aneurysms. According to the authors' surgical experience and clinical experience, the LTOA can be considered an alternative surgical route to supratentorial aneurysm surgery.

Contribution of the xenograft bone plate-screw system in lumbar transpedicular stabilization: An in vivo study in dogs.

OBJECTIVES: Xenograft bone plate-screws (XBPSs) can be alternative tools in lumbar transpedicular stabilization (TS). The aim of this study was to show biomechanical and histopathological contribution of the XBPSs system in lumbar TS. MATERIALS AND METHODS: Fifteen (n = 15) hybrid dog and ten (n = 10) L2-4 cadaveric specimens were included in the study. The dogs were separated according to surgical techniques: L3 laminectomy and bilateral facetectomy (LBF) in Group I (experimental group [EG I] (n = 5), L3 LBF plus TS with metal plate-screws (MPSs) in Group II (EG II) (n = 5), and L3 LBF plus TS with XBPSs in Group III (EG III) (n = 5). The cadaveric specimens were separated to L2-4 intact in Group I (CG I), (n = 5), and L3 LBF in Group II (CG II), (n = 5). The dogs were sacrificed at the end of 3rd month, and their L2-4 spinal segments were en bloc removed and prepared as in control groups. Flexion, extension, left-right bending, rotation, and compression tests were applied to all segments. Stiffness values were calculated and analyzed statistically. All dog segments were evaluated histopathologically. RESULTS: XBPS system showed a higher average stiffness values for left bending, extension, flexion, and compression compared to MPS, but these differences were not statistically meaningful. XBPS system had superiority to the fusion formation, as well. CONCLUSIONS: XBPSs provide stability and help the fusion formation, but this system does not have a biomechanical advantage over MPS system in TS.

Comparison of Stabilization and Fusion Methods with Xenograft Plate Screws After Anterior Lumbar Corpectomy in Dogs.

AIM: Fusion development is the primary goal in spinal surgeries that are conducted for the treatment of vertebral body pathologies such as trauma, tumor and infection. Stabilization using metal plate screws together either with an autograft, allograft or xenograft is used. We evaluated fusion development in stabilizations that were carried out with xenograft (XG) with XG plate-screw (XPS) and XG with metal plate-screw (MPS) systems in dogs" lumbar vertebrae (L5-7 segment) in terms of radiological, biomechanical and histopathological aspects. MATERIAL AND METHODS: The animals were divided into 4 groups, each including 5 subjects. The experiment consisted of Control group 1 which did not go through any procedure and was stabilized, Control group 2 which underwent instability with only L6 anterior corpectomy, Experimental group 1 which was stabilized with intervertebral XG and XPS after L6 corpectomy, and Experimental group 2 which was stabilized with intervertebral XG and MPS after L6 corpectomy. Development of fusion in the Experimental groups 1 and 2 was evaluated in terms of radiological and histopathological aspects. RESULTS: Comparison of Control and Experimental groups showed an increase in resistance in all activities on biomechanical tests (p < 0.01). Fusion development was observed in the radiological and histopathological examinations of the subjects in the Experimental group. On the other hand, Experimental groups 1 and 2 did not show a significant difference in the biomechanical test comparisons (p > 0.05). CONCLUSION: Xenograft plate screws and metal plate screws provide equivalent fusion and stabilization in anterior lumbar stabilization.

Surgical anatomy of the cavernous sinus, superior orbital fissure, and orbital apex via a lateral orbitotomy approach: a cadaveric anatomical study.

BACKGROUND: Tumors of the middle fossa or cavernous sinus (CS), or intraorbital tumors, can penetrate each other through the superior orbital fissure (SOF) or neighboring tissue. These complicated pathologies are often treated with highly invasive surgical procedures. In this article, we demonstrate surgical anatomic dissections of the CS, SOF, orbital apex (OA), and dura mater extending to the periorbita from the middle fossa, by performing an epidural dissection via a lateral orbitotomy approach, and discuss findings that may provide guidance during surgery in these regions. METHODS: Lateral orbitotomy was performed on latex-injected cadaver heads by making a 2-cm skin incision lateral to the lateral canthus, drilling the lesser and greater sphenoid wings that form the SOF borders, and removing the bone section between the middle fossa and orbit. Dura mater from the middle fossa to the periorbita was exposed to perform anterior clinoidectomy. Meningeal dura was dissected from the endosteal dura, which forms the lateral wall of the CS, to expose the CS, SOF, and OA for dissections. RESULTS: Changing the orientation of the microscope from posterior to anterior enabled regional control for dissection from the Gasserian ganglion to the OA. Cranial nerves that pass through the CS, SOF, and OA were dissected and exposed. The annular tendon was opened, revealing the oculomotor nerves and its branches, as well as the abducens and nasociliary nerves, which pass through the oculomotor foramen and course within the OA and orbit. CONCLUSIONS: This approach causes less tissue damage; provides control of the surgical area in spheno-orbital tumors invading the fissure and foramen by changing the orientation of the microscope toward the orbit, OA, SOF, CS, and middle fossa; and expands the indication criteria for lateral orbitotomy surgery. This approach, therefore, represents an alternative surgical method for excising complicated tumors in these regions.

Endoscopic Evacuation of Subdural Collections.

AIM: Intraoperative use of the endoscope is a hot topic in neurosurgery and it gives broader visualization of critical and hardlyreached areas. Endoscope-assisted surgical approach to chronic subdural haematoma (SDH) is a minimally invasive technique and may give an expansion to the regular method of burr-hole haematoma drainage. MATERIAL AND METHODS: Endoscope-assisted haematoma drainage with mini-craniotomy was performed over a 24-month period, and prospectively collected data is reviewed. A total of 10 procedures (8 patients) were performed using the endoscopeassisted technique. Four of them were chronic SDH and six were subacute SDH. RESULTS: Procedures were extended 20 minutes in average because of endoscopic intervention. There was no extra-morbidity through the study as a consequence of endoscopic assessment. CONCLUSION: Endoscope-assisted techniques can make the operation safe in selected circumstances with improved intraoperative visualization. It may likewise take into consideration the identification and destruction of neo-membranes, septums and solid clots. In addition, the source of bleeding can be easily coagulated. The endoscope-assisted techniques, with all of these features, can alter the pre- and intra-operative decision-making for selected patients.

Intraocular neuromuscular choristoma: a case report and literature review.

BACKGROUND AND IMPORTANCE: Neuromuscular choristomas (NMCs) are rare benign tumors of the peripheral nerves. Although histopathological characteristics of this unusual lesion have been recognized, in this regard, neuroimaging findings have not been well described previously. We report the first intraconally located NMC affecting the oculomotor nerve, with histopathological and radiological characteristics. CLINICAL PRESENTATION: A 10-year-old girl presented with sudden-onset left temporal and retro-orbital pain. Magnetic resonance imaging scans demonstrated a small, capsulated, retro-orbital, intraconal solid lesion that was diagnosed as an atypical dermoid cyst preoperatively. The tumor was resected subtotally. Postoperatively, the patient became pain free, but ipsilateral ptosis and upward eye movement failure developed. Histologically, the lesion consisted of well-differentiated striated muscle fibers intermingled with mature nerve elements consistent with the NMC. CONCLUSION: Although intracranial NMCs need histological confirmation for diagnosis, neuroimaging might contribute to the preoperative diagnosis and management strategy of treatment. We report the first intraconal NMC, which should be considered in the differential diagnosis of intraorbital tumors.

Anatomical study of the cavernous sinus emphasizing operative approaches.

AIM: The aim of this article is to describe the microsurgical anatomy of the cavernous sinus, the triangles, and the osseous relationships in the region with special attention to the relationships important in surgical approaches on the intracavernous structures. MATERIAL AND METHODS: Fifty cavernous sinuses obtained from twenty-five cadaver heads were studied in detail using magnification. Stepwise dissections of the cavernous sinuses performed to demonstrate the intradural and extradural routes, anatomy of the triangles and osseous relationships in the region. RESULTS: The main branches of the intracavernous portion of the carotid artery were the meningohypophyseal, the inferior cavernous sinus, and McConnell;s capsular artery . The main branches of the meningohypophyseal trunk were the tentorial, the dorsal meningeal, and the inferior hypophyseal artery. There were variations of the main branches of the meningohypophyseal trunk. The sixth cranial may splite into rootlets as it passes lateral to the carotid artery. There were size and shape variation of the triangles. CONCLUSION: Aprecise understanding of the bony relationships, the anatomy of the triangels and neurovascular content of the cavernous sinus, together with the use of cranial base and microsurgical techniques are necessary for safer surgery. Asingle approach is not capable of providing exposure of all parts of the sinus.

FHIT gene sequence variants and reduced Fhit protein expression in glioblastoma multiforme.

Molecular studies have an important role in the elucidation of the mechanisms involved in Glioblastoma multiforme (GBM) development. The occurrence of FHIT gene alterations, which has an important role in different cancers, has not yet been studied well in GBM. We aimed to investigate the occurrence of alterations of FHIT gene sequence and protein expression in the GBMs. Sequence alterations in exons 5-9 of the FHIT gene were screened in 63 GBMs using the single-strand conformational polymorphism method, followed by DNA sequencing. Additionally, the level of Fhit protein expression in tissues of 48 tumors was assessed by immunohistochemistry (IHC). In our investigation, FHIT gene alterations in the coding region were detected in 11 of the 63 GBM cases (17.5%). Two different sequence variants were determined: one novel missense variant (G-->C transition at codon 49) and one previously described silent alteration (C-->T transition at codon 88). Using web-based programs, such as SIFT and ESEfinder, it was determined that both alterations might have caused significant modification on protein function. In addition, we identified a previously reported an intronic polymorphism (T-->A transition at IVS8-17) in 47.5% of cases as a similar rate (45%) in the control group. Moreover, it was observed that Fhit protein expression was reduced in 87.5% of tumors. In conclusion, the reduction or loss of Fhit protein expression by genetic alterations or epigenetic mechanisms in GBM might be associated with brain tumorigenesis.

Is supratentorial pressure difference clinically relevant? Analysis of 55 consecutive cases by bilateral intracranial pressure monitoring.

OBJECTIVE: The purpose of this study is to explore the possibilities of an early warning system by measuring intracranial pressure differences in order to prevent secondary insults to the injured brain. METHODS: Fifty-five cases with a Glasgow coma scale (GCS) score 8 or below who presented with intracranial hypertension due to various intracranial pathologies underwent bilateral intraparenchymatous intracranial pressure (ICP) monitorization in an attempt to find out the existence of interhemispheric pressure differences. ICP values were recorded every 30 minutes during the first 24 hour interval. Patients were stratified into two groups as diffuse and focal according to the magnitude of their pathologies. Focal cases were also grouped according to lesion size and/or midline shift. RESULTS: ICP differences that necessitated changes in the treatment were found at different time intervals in patients with focal lesions, but these did not reach statistical significance within the whole group (p > 0.05). There were significant percentage differences between focal I and II groups in correlation with lesion side and non-lesion side within the first 4.5 hours (p < 0.05). There was a significant difference within the first 3 hours between diffuse and focal II groups (p < 0.05). DISCUSSION: In patients with focal lesions, although more pronounced in focal II group, apparent pressure differences between two hemispheres within the first hours of admission were found. These pressure differences were related to the volume of the intracranial pathology. ICP monitorization from the lesion side is reasonable as an early forewarning procedure and this might prevent the development of secondary insults by providing the exact ICP values of the patients.

Contribution of the xenograft bone plate-screw system in lumbar transpedicular stabilization of dogs: an in-vitro study.

We performed biomechanical comparison of a xenograft bone plate-screw (XBPS) system for achieving cadaveric lumbar transpedicular stabilization (TS) in dogs. Twenty dogs' cadaveric L(2-4) lumbar specimens were harvested and their muscles were removed, but the discs and ligaments were left intact. These specimens were separated to four groups: the L(2-4) intact group as control (group I, n = 5), the L(3) laminectomy and bilateral facetectomy group (LBF) (group II, n = 5), the LBF plus TS with metal plate-screw group (group III, n = 5) and the LBF plus TS with XBPS group (group IV, n = 5). Five kinds of biomechanical tests were applied to the specimens: flexion, extension, left-right bending and rotation. The averages of the 16 stiffness values were calculated and then these were statistically analyzed. The statistical results show that the XBPS system contributes spinal stability and this system can be a good choice for achieving TS.

Comparison of lateral and superior walls of the pituitary fossa with clinical emphasis on pituitary adenoma extension: cadaveric-anatomic study.

Pituitary adenomas extend to the suprasellar region via diaphragmal passage and extend to the cavernous sinus via the medial wall (MW). Better understanding of the dynamics of suprasellar and parasellar extension of sellar region pathologies requires microanatomical comparison of diaphragma sellae (DS) and the MW of the cavernous sinus. This study provides the first detailed quantitative assessment between DS and MW of the cavernous sinus. Microanatomical details and histopathological examinations of the DS and MWs of the cavernous sinus were studied in sphenoid block samples obtained from adult cadavers, and the thicknesses of the DS and the MW of the cavernous sinus were measured. Mean thickness of the DS was 216.73 +/- 51.26 microm in the center and 367.33+/-133.66 microm in the periphery. Mean thickness of the lower third of the MW was 161.53+/-53.86 microm and that of the upper third was 278.46+/-162.79 microm. Difference between the thicknesses of the upper and lower thirds was significant (P<0.001). When the central thickness of the DS and lower third of the MW were compared, a significant difference was found (P<0.01). Our measurements suggest that when the DS is thick and the stalk opening is complete, the thickness of the lower third of the medial wall could be the major determinant of parasellar extension.

Impact of novel PTEN mutations in Turkish patients with glioblastoma multiforme.

Glioblastoma multiforme (GBM) represents the most common and aggressive type of primary neoplasms of the central nervous system. The PTEN (phosphatase, tensin homologue, deleted on chromosome TEN; MIM # 601728) tumor suppressor gene has an essential biological role in the formation of glioblastomas. It is known that there are variations in genetic alterations in tumors that develop in patients with different ethnic backgrounds and because there is no study evaluating PTEN mutation in Turkish patients with GBM, we aimed to realize the present study. We investigated 62 GBM tumors for mutations of the PTEN gene using single strand conformational polymorphism (SSCP) method followed by DNA sequencing. As a result of our investigation, PTEN mutations were detected in 15 of 62 tumors (24.19%). Nine different sequence variants were identified: one novel promoter site mutation (5'UTR -9C-->T), one novel intronic mutation (IVS2-2delA), four novel point mutations (61A-->G, 105T-->G, 248C-->G, and 364C-->G), two novel frameshift mutations (213delC) and 378delGATA) and one previously reported global exonic transition type mutation (129G-->A). Since the majority of PTEN mutations identified in the present study are novel, we believe that these alterations may be specific to Turkish population. Furthermore, though no significant correlation was found between PTEN mutations and histopathological properties of GBM tumors, our findings indicate that localizations of mutations in PTEN gene may have an effect on clinical aggressiveness of GBM tumors.

Lumbar spinal extradural angiolipomas. Two case reports.

Spinal extradural angiolipomas are benign tumors mostly localized in the thoracic region. A 50-year-old woman and a 36-year-old man presented with rare lumbar spinal angiolipoma manifesting as low back pain but without neurological signs. Magnetic resonance imaging showed lumbar extradural tumors at the L4-5 and L1-2 levels, respectively. Each patient underwent complete surgical resection of the epidural tumors. Histological examination revealed characteristics of angiolipomas in both tumors. The symptoms of both patients improved postoperatively and no recurrence of the tumors was found 1 year after surgery.

Cerebrospinal fluid leakage complicating skull base fractures: analysis of 81 cases.

The aim of this study was to evaluate the results of conservative and surgical management options for traumatic cerebrospinal fluid (CSF) leakage complicating skull base fractures. The subjects were 81 patients who were treated between 1996 and 2003 for CSF leaks that had persisted for 24 h or longer after head injury. For each case the medical records were reviewed, and the data collected were as follows: demographic features, clinical and radiological findings, management options, complications and outcome scores. Analysis was done with patients grouped according to Glasgow coma scale (GCS) score at admission (8), and findings for three treatment methods (conservative, CSF drainage, surgery) were evaluated. In 32 cases (39.5%), the CSF leakage resolved spontaneously, and the mean hospital stay for these patients was 14+/-11 days. Twenty-four patients (29.6%) were treated by CSF drainage, and seven of these individuals ultimately required surgery to close the leak. Hospital stay was 17+/-7 days. Twenty-five patients (30.9%) underwent surgery as the initial treatment step, and the mean hospital stay for these individuals was 15+/-9 days. The large majority (74.2%) of patients with admission GCS scores 8 resolved spontaneously. The factors that had a critical influence on outcome in this series were level of consciousness on admission and presence of additional intracranial pathology associated with CSF leakage within cases of traumatic CSF fistulae due to skull base fractures. Treatment decisions should be dictated by the severity of neurological decline during the emergency period and the presence/absence of associated intracranial lesions. The timing for surgery and CSF drainage procedures must be decided with great care and with a clear strategy. The authors offer a treatment algorithm.

Critical care management of severe head injury in children.

BACKGROUND: Our aim was to analyze prognostic factors and their association with outcome among children with severe head injury. METHODS: We conducted a retrospective study among children (n=55) with severe head injury [Glasgow Coma Score (GCS) ?8] who were admitted to our Neurosurgical Intensive Care Unit (ICU) from January 1996 to September 2003. The patients were immediately evaluated with cranial computed tomography (CT) for the severity of head injury as well as for the causes of secondary insults such as hypoxia and hypotension, metabolic and hematological alterations. Outcome analysis was assessed according to Glasgow Outcome Scale Score (GOS) six months after the injury. RESULTS: A poor result occurred in 31 patients (57%) while 24 patients (43%) had favourable results. Multivariate analysis showed significant independent prognostic effect for admission mean systolic blood pressure, presence of hypoxia, multiple trauma, admission GCS score and multiple intracranial lesions (p<0.05). Admission WBC counts and serum glucose levels were not correlated with GOS. CONCLUSION: This study describes clinicoradiologic findings and prognostic factors regarding severe head injury in pediatric patients. The goals of managements of pediatric patients with severe traumatic head injury include normalizing intracranial pressure, optimizing arterial blood gases and systemic blood pressure, and prevention of factors that exacerbate secondary brain injury.

Quadrigeminal cistern lipoma.

Intracranial lipomas are rare benign congenital neoplasms accounting for 0.1 to 0.5% of all primary brain tumours. Approximately 50% are associated with other cerebral developmental disorders. These slow growing benign lesions are usually asymptomatic and rarely require surgery. We report the case of a 37 year old woman presented with signs of raised intracranial pressure. Computerized tomography and magnetic resonance imaging demonstrated a quadrigeminal cistern lipoma compressing the aqueduct of Sylvius. The patient underwent surgery and a distinct plane of cleavage between the lipoma and the adjacent neural structures was found, allowing total removal of the lesion. Postoperatively, the patient was relieved of her original symptoms but developed akinetic mutism which lasted for two weeks. Intracranial lipomas rarely become symptomatic and surgery is seldom required. If the lesion progresses and causes symptoms of raised intracranial pressure or compression of neural structures, surgical intervention is indicated. Total removal should not be attempted unless a plain of cleavage between the lesion and adjacent neural structures is present. Surgical manipulation should be minimised to avoid complications.

Using the sac membrane to close the flap donor site in large meningomyeloceles.

If a large transposition flap with or without muscle is used for closure of a large meningomyelocele defect, then, a part of the donor site of the flap can be closed by split thickness skin graft, which produces an additional donor wound for the patient. We used the sac membrane instead of split thickness skin graft for closure of donor sites of fasciocutaneous flaps and latissimus dorsi musculocutaneous flaps employed to cover large meningomyelocele defects. This technique was used in three thoracolumbar and in two lumbosacral meningomyelocele patients. The sac membrane was prepared like a full thickness skin graft. Follow-up in five patients has ranged from 1 to 18 months, with a mean of 10.6 months. The donor sites that were closed by the sac membrane exhibited complete healing in all patients. We conclude that the sac membrane supplies a reserve of epithelialised tissue that can be used for repair of the meningomyelocele defects.

Sellar-parasellar brown tumor: case report and review of literature.

Brown tumors are the end stage of primary or secondary hyperparathyroidism. Such lesions are rare because hyperparathyroidism is now usually diagnosed and treated before they develop. Skeletal bone is most frequently involved, whereas sellar-parasellar involvement is extremely rare. We report a patient with a brown tumor involving the sellar-parasellar region associated with primary hyperparathyroidism. The patient's clinical history and biochemical and radiological tests were used for the diagnosis. Excision of the sellar-parasellar mass enabled histopathological confirmation and surgical decompression of neural structures. After the transsphenoidal surgery, excision of a parathyroid adenoma normalized the patient's metabolic status. Brown tumors are rarely associated with complications but occasionally may compress neural structures such as the optic nerve as they enlarge.

Transient Anton's syndrome: a presenting feature of acute epidural hematoma at the confluens sinuum.

Although unilateral epidural hematomas are well known, bilateral presentation, especially at the confluens sinuum, is uncommon, and its diagnosis may be delayed, thus causing morbidity. We report a case of acute posttraumatic cortical blindness due to epidural hematoma at the confluens sinuum caused by venous sinus tearing. The epidural hematoma was evacuated and the dural tear was repaired. The patient remained alert throughout the hospitalization. Examination of the visual field revealed recovery postoperatively, and the patient was discharged. We discuss the pathological mechanisms of transient blindness. The importance of anopsia as an early sign of epidural hematoma is emphasized.