Heat generation by ultrasonic bone curette comparing with high-speed drill.

BACKGROUND: Ultrasonic bone curettes have been used as with high-speed drills. However, the amount of heat generated by the ultrasonic bone curette is not well known. This study quantitatively assessed the heat generated by an ultrasonic bone curette and compared it to that by a high-speed drill. METHODS: The thermal change in a swine skull during bone curetting using an ultrasonic device and a high-speed drill were assessed. The investigation focused on the type of surgical manipulation (brush-like strokes vs. pushing motion) and irrigation (room temperature vs. cold water; low-volume irrigation vs. high-volume irrigation). RESULTS: The thermal elevation during drill use was suppressed when using brush-like strokes compared to pushing motion (brush-like strokes, 44.7 °C; pushing motion, 69.2 °C; p < 0.01). Cold-water irrigation while drilling had a small effect compared to room temperature (RT) water (RT, 44.7 °C; cold, 35.2 °C; p = 0.12). The temperature generated by the curette was higher than that generated by the drill (curette, 72.5 °C; drill, 44.7 °C; p < 0.01). High-volume irrigation was required to reduce the heat generated by the curette (no irrigation, 88.6 °C; low-volume, 72.5 °C; high-volume, 60.5 °C; p < 0.01). CONCLUSIONS: The ultrasonic bone curate generated more heat than the high-speed drill. During surgical manipulation, the use of brush-like strokes by both the high-speed drill and the ultrasonic bone curette is necessary to avoid excess thermal elevation. Irrigation with RT water is sufficient to avoid heat generation. High-volume irrigation is required to reduce the heat generated by the curette.

Microvascular decompression for hemifacial spasm associated with the vertebral artery.

In patients with vascular compression syndromes, the preoperative recognition of the cranial nerves and compressed vessels will contribute to improved surgical results. The aim of this study was to clarify the pathophysiology of hemifacial spasm (HFS) associated with the vertebral artery (VA) and to assess the value of preoperative imaging. Fifty-three consecutive patients with HFS underwent microvascular decompression (MVD). Of these, 18 cases of HFS were associated with the VA; this case series was compared with the remaining non-VA-associated HFS. For preoperative assessment, magnetic resonance imaging (MRI) was performed. Since January 2006, fusion imaging has been performed by combining MRI and computed tomography angiography. Of the 18 cases of VA-associated HFS, 17 (94.4 %) were on the left side; this was significantly higher than in the non-VA-associated HFS cases (p < 0.0001). The VA was attached to the root exit zone (REZ) directly in three cases. In the other 15 cases, the VA was compressing the REZ indirectly as a result of other intervening vessels. In all cases, preoperative imaging fully simulated the status of the REZ. The symptom disappeared in 17 cases (94.4 %) after MVD, and there was no significant difference in the surgical results between the VA-associated group and the non-VA-associated group (p = 0.9925). HFS associated with VA is not a rare condition. Preoperative recognition is thus important to the improvement of surgical results. Fusion imaging is useful to determine the status of the REZ, especially in indirect VA-associated HFS.

[Primary clear cell carcinoma of the skull base and paranasal cavity: a case report].

We described a case of primary clear cell carcinoma (CCC) of the paranasal cavity and skull base. A 59-year-old female experienced chronic nasal obstruction and double vision. Computed tomography (CT) scan revealed a mass lesion of the paranasal cavity, reaching the skull base and intracranial zone. We performed a biopsy by endonasal endoscopic surgery and pathological examinations revealed the tumor was a clear cell carcinoma. No primary tumor was identified on evaluation of the whole body by CT scan and FDG-PET (18 fluorodeoxy glucose positron emission tomography) scan, so we diagnosed a primary CCC of the paranasal cavity. We decided to use stereotactic radiation therapy. Neurologically, her diplopia was improved. The patient is well at 2 years of follow-up with no evidence of local enlargement. There are some reports about the metastatic sinonasal CCC, but there are few reports about primary nasal and sinonasal CCC. This is the fourth case report of primary nasal and sinonasal CCC.

Glioblastoma simultaneously present with adjacent meningioma: case report and review of the literature.

The simultaneous occurrence of multiple primary intracranial tumors has been reported previously. However, most of these tumors arise after cranial radiotherapy or in association with familial tumor syndromes. Double tumors of different histologies that are unrelated to radiotherapy or genetic disorders are very rare. We present a case of two primary intracranial tumors occurring simultaneously at adjacent sites. Preoperative gadolinium-enhanced magnetic resonance imaging of these tumors revealed a single continuous lesion. Postoperative histological examination revealed the presence of two distinct tumors, meningioma and glioblastoma multiforme. To elucidate the mechanism of synchronous tumor formation, we performed immunohistochemical analysis of the proteins involved in the receptor tyrosine kinase, Wnt, and Notch signaling pathways. These analyses showed that platelet-derived growth factor (PDGF) receptors-alpha and beta were overexpressed in both tumors, thereby indicating the oncogenic effects of activated signaling of these receptors. The PDGF-mediated paracrine system may induce one tumor from another.

Suprasellar hemangioblastoma.

A 59-year-old woman presented with disturbance of consciousness and decreased visual acuity caused by a suprasellar mass identified on MRI. A bifrontal interhemispheric approach allowed removal of the top and lateral sides of the tumor from the wall of the third ventricle. The hypothalamus appeared to be the origin of the mass, which proved to be hemangioblastoma, a rare tumor in this location.

Anatomical variations in pneumatization of the anterior clinoid process.

OBJECT: An anterior clinoidectomy can provide enormous benefits, facilitating the management of paraclinoid and upper basilar artery lesions, but it also carries the potential risk of cerebrospinal fluid leaks. The aim of this study was to assess the variation in the pneumatization of the anterior clinoid process (ACP) in an attempt to reduce the complications associated with an anterior clinoidectomy. METHODS: The authors analyzed the anatomical variations in the pneumatization of the ACP and optical strut (OS) in 600 sides of 300 consecutive patients by using multidetector-row computed tomography (CT). Computed tomography scans with a 0.5-mm thickness were obtained, and coronal and sagittal reconstructions of the images were displayed in all cases. Pneumatization of the ACP was found in 9.2% of all sides. The origin of pneumatization was the sphenoid sinus in 81.8% of all the sides, the ethmoid sinus in 10.9%, and both of these sinuses in 7.3%. Pneumatized patterns were divided into three groups according to the route: 74.5% were Type I, in which pneumatization occurred via the OS; 14.5% were Type II, pneumatization via the anterior root (AR); and 10.9% were Type III, pneumatization via both the OS and the AR. The origin of pneumatization and the pneumatization pattern showed statistical dependence (p < 0.001). Pneumatization of the OS beyond its narrowest point was found in 6.8% of all sides. CONCLUSIONS: An awareness of the different variations in pneumatization can prevent destruction of the mucous membrane and facilitate orientation during reconstruction with cranialization. During an anterior clinoidectomy, preoperative CT assessments are necessary to evaluate pneumatization of the ACP.

[Cerebrospinal fluid leak due to inner ear malformations].

A case of inner ear anomalies associated with recurrent meningitis found in a 66-year-old female is reported. The patient had had 2 episodes of meningitis in the previous one year period. Multidetector-row CT of the temporal bone and three-demensional fast imaging employing steady-state acquisition MRI revealed dysplasia of the bony labyrinth and enlarged fundus of the internal auditory canal (IAC). During surgical treatment, we confirmed the cerebrospinal fluid (CSF) leakage through a bony defect in the stapedial footplate. The inner ear was obliterated and contained small pieces of temporal fascia. A meningitis or CSF leakage due to inner ear malformation is extreamly rear condition for neurosurgeon. Though we always have to take it into condideration as a cause of CSF leakage.

[Primary intraosseous cavernous hemangioma in anterior clinoid process].

Primary intraosseous cavernous hemangiomas (PICHs) are rare tumors, and there are no previous reports of cases with a tumor at the anterior clinoid process. We report a case of a PICH at the anterior clinoid process in a 66-year-old female presenting with headaches and visual impairment. CT and MR imaging showed a mass in the anterior clinoid process. The lesion showed hyperintensity on T1- and T2-weighted imaging, and gadolinium was homogenously enhanced. The lesion was removed surgically, and histologically confirmed as a cavernous hemangioma. Preoperative examinations could not provide a definitive diagnosis. A brief clinical and radiological review of the literature is presented.

[Superior sagittal sinus thrombosis in a case of longstanding systemic lupus erythematosus].

A 33-year-old female who had been on a steroid treatment for the past 14 years due to systemic lupus erythematosus (SLE) visited our hospital complaining of mild headache. No neurological deficit and no positive serologic tests for lupus anticoagulants (LAC) and anticardiolipin antibodies (aCL) were noted. Only a mild inflammatory change was observed on routine hematological examination. On neuroradiological examination, MRI revealed thickened falx cerebri and tentorium cerebelli, and an empty delta sign. These findings were suggestive of sinus thrombosis of superior sagittal sinus (SSS). Angiograms clearly demonstrated occlusion of the posterior part of superior sagittal sinus and transeverse sinus (TS). Conservative treatment was chosen because of no evidence of intracranial hypertension. There was no deterioration in her general and neurological status during her hospital stay and she was discharged. Longstanding vasculitis and pachymeningitis related to lupus erythematosus might be the probable cause of the sinus thrombosis in this case.

Surgical management of the recurrence and regrowth of craniopharyngiomas.

OBJECT: The authors performed a retrospective analysis of a consecutive series of craniopharyngiomas and their recurrences, which were managed with surgery alone. METHODS: In the past 20 years, 37 consecutive patients with craniopharyngiomas underwent surgery without adjuvant radiotherapy. During that period there was a consistent strategy that surgical management was the first choice of treatment whenever possible. Of these 37 patients, 11 experienced tumor recurrence (29.7%) during the mean follow-up period of 11.1 years. Of these 11 patients, seven experienced recurrence after neuroimaging-confirmed total removal, and four patients experienced recurrence after partial or incomplete removal. In these 11 patients, surgical removal was performed 17 times. Using a proper surgical approach (mainly a basal interhemispheric approach) and meticulous microsurgical techniques, total removal of the recurrent tumor was achieved in nine surgeries (52.9). The mortality and morbidity rates associated with these 17 surgeries were 0% and 9.1%, respectively. In most cases, visual function was preserved or improved and intellectual performance was also preserved. CONCLUSIONS: Recurrence of craniopharyngioma can be safely managed by using meticulous contemporary microsurgical techniques without additional radiotherapy. The role of surgery and adjuvant radiotherapy for craniopharyngiomas may vary in the future, depending on innovations in treatment and technology. Nevertheless, surgery can be still a major therapeutic option in the management of recurrent craniopharyngiomas.

Entrapment neuropathy of the optic nerve due to hyperostosis associated with congenital anemia.

The authors report on the case of a 14-year-old boy who presented with bilateral visual impairment due to optic canal stenosis caused by hyperplasia of the bone marrow arising from anemia. The patient had hereditary hemolytic anemia with unstable hemoglobin of the Christchurch type. This congenital form of anemia caused hyperplasia of the bone marrow as well as hyperostosis of the entire calvarial bone, which in turn led to optic canal stenosis. The patient underwent surgical decompression of the optic canal, resulting in significant improvement in visual acuity. Pathological findings in the calvarial bone indicated hypertrophic bone marrow with no other specific features such as neoplastic pattern or fibrous dysplasia. With the exception of objective hearing impairment, no other significant cranial neuropathy has been detected thus far. On reviewing the published literature, this case was found to be the first in which hyperostosis due to congenital anemia resulted in symptomatic entrapment neuropathy of the optic nerve. The authors concluded that surgical decompression effectively improves visual acuity.

T2 reversed fast spin-echo image and enhanced three-dimensional surface MR angiography for the diagnosis of cerebral arteriovenous malformations.

Although conventional neuro-imaging of cerebral arteriovenous malformation (AVM) supports preoperative evaluation, it is still difficult to visualise the detailed anatomical conformation of the AVM, the point of nidus, the feeding arteries or draining veins, and the three-dimensional configuration of nidus in the sulcus or gyrus. In the present study, we investigated the efficacy of enhanced three-dimensional surface MR angiography (surface MRA) and T2 reversed imaging (T2R imaging) in diagnosis and surgical planning for cerebral AVMs. Surface MRA clearly demonstrated nidus adjacent to eloquent area and three-dimensional figures of feeding arteries and draining veins. T2R imaging was useful to differentiate sulcal AVM from gyral AVM, and to estimate the depth of the nidus in the parenchyma. Although it has generally been assumed that nidus is present in the gyrus, T2R imaging clearly demonstrates that most of the nidus is in the sulcus and is possible to be dissected and removed without damaging parenchyma. Indeed, these imaging methods supply clinically relevant data that is difficult to obtain with conventional neuro-imaging and provide better details of lesions, informing surgical planning and decision-making.

[A case of sinonasal carcinoma with intracranial invasion treated by a multidisciplinary team].

We report a case of a 66-year-old male with diffuse infiltration of neoplasm from the paranasal sinuses to the orbit and left cerebral hemisphere, associated with prominent edema. Initial complaints were headache and swelling of the forehead, which were followed by progressive symptoms, such as epistaxis, dacryops, and severe pains. Neuroimaging showed marked invasion of a neoplasm from the left paranasal sinuses into the intracranial space and to the frontal skull. Radical removal of the neoplasm and left orbital content with reconstruction of the anterior skull base using musculocutaneous flap was carried out by a multidisciplinary team. The pathological diagnosis was "poorly differentiated carcinoma from the paranasal sinus". Postoperatively the patient received radiation and chemotherapy. He is still alive with mild right hemiparesis and mild dysphasia, more than 2 years after surgery.

[111In-DTPA cisterno SPECT for the diagnosis of CSF rhinorrhea: case report].

The authors report on a patient with postoperative CSF (cerebrospinal fluid) leakage subsequent to transsphenoidal surgery where cisterno SPECT (single photon emission computed tomography) demonstrated the precise location of a CSF fistula. Seven months after surgery, the patient suffered from CSF rhinorrhea and headache. MRI (Magnetic Resonance Imaging) revealed significant contrast on T1-weighted images resulting from measurements in the right sphenoid sinus, which were hyperintense relative to CSF. On the basis of signal intensity differences, MRI could not distinguish between CSF leakage and postoperative scarring. Therefore, we performed cisterno SPECT at the same time as RI cisternography with intrathecal lumbar injection of 111In-DTPA which revealed dramatic accumulation of the tracer in the right sphenoid sinus. The patient underwent re-operation via a transsphenoidal approach, and the CSF leakage was repaired using fat-in-fibrin glue and the sella floor was reconstructed by hydroxyapatite platinge. These results suggest that cisterno SPECT may be useful in identifying the precise location of CSF fistulae, while other techniques fail to show evidence of CSF leakage.

Midsubtemporal ridge as a predictor of the lateral loop formed by the maxillary nerve and mandibular nerve: a cadaveric morphological study.

BACKGROUND: The lateral loop formed by the maxillary nerve (V2) and the mandibular nerve (V3) consists of a part of the far lateral triangle of the cavernous sinus. Because this triangle becomes a surgical corridor of the preauricular infratemporal fossa approach and a landmark of the extradural approach for the ganglion-type trigeminal schwannomas, identification of the lateral loop has important implications at the early stage of middle cranial base surgery. We realized that a bony ridge usually existed just lateral to the lateral loop. OBJECTIVE: To nominate midsubtemporal ridge (MSR) as the name for this anatomically unnamed bony ridge and to clarify its features. METHODS: Using 35 cadaver heads, we measured the shape of the MSR on both sides and the distance between the MSR and the adjacent structures. RESULTS: The MSR was recognized in 60 of 70 specimens (85.7%). The bony protrusion was 2.9 ± 1.1 mm in height, 6.0 ± 2.1 mm in width, and 9.1 ± 3.2 mm in length. A single peak with anteroposterior length was common in 47 of 60 specimens (78.3%). The MSR was located at the midpoint of the V2 and V3 in 28 specimens (46.7%) and existed 10.7 ± 3.6 mm lateral from the line that bound the foramen rotundum and the foramen ovale. CONCLUSION: We demonstrate morphological characteristics of the MSR. These data on the MSR will assist the surgeon in identifying the lateral loop as a surgical landmark during middle cranial base surgery.

Quantitative analysis of adverse events in neurosurgery.

OBJECTIVE: : It is well recognized that the occurrence rate of adverse events related to surgical procedures is considerably high in neurosurgery compared with other specialties. The purpose of this study was to quantitatively determine the occurrence rate of adverse events related to surgery and endovascular intervention in neurosurgery. METHODS: A conference on adverse events related to treatments (morbidity and mortality conference) has been held every month for the past 2 years in our department. At these conferences, all adverse events are evaluated and discussed. Adverse events include not only the unexpected complications, but also the neurological and general deterioration predicted before surgery. All the adverse events are discussed in terms of the conceivable causes, their association with the procedures, and the possibility of prediction and avoidance. RESULTS: One hundred eighty-two events (28.3%) among 643 neurosurgical interventions over 2 years were recognized as adverse events. Among these 182 adverse events, 165 (90.7%) were closely related to procedures and 125 events (68.7%) were predictable before or during the procedures. However, even when retrospectively reviewed, only 6 (3.3%) of events were deemed avoidable. Of these 6 avoidable events, there were only 2 (1.1%) that were considered to have been caused by error. CONCLUSION: Adverse events are not invariably rare in neurosurgery. Most of them are predictable; however, their avoidance is not necessarily easy. Avoidable adverse events caused by medical errors were observed in only 1.1% of cases.

Susceptibility-weighted magnetic resonance imaging for the detection of cerebral microhemorrhage in patients with traumatic brain injury.

The sensitivity of susceptibility-weighted magnetic resonance (MR) imaging was compared with conventional MR sequences, including T(2)*-weighted imaging, and computed tomography for the detection of cerebral hemorrhages in 15 patients with head injury. Susceptibility-weighted imaging detected a mean of 76+/-52 (total 1132) hypointense spotty lesions, compared to a mean of 21+/-19 (total 316) detected by T(2)*-weighted imaging (p<0.0001, paired t-test). Susceptibility-weighted imaging is extremely sensitive for the visualization and detection of microhemorrhages.