Prediction of thrombolytic therapy after stroke-bypass transportation: the Maria Prehospital Stroke Scale score.

There is no prehospital stratification tool specifically for predicting thrombolytic therapy after transportation. We developed a new prehospital scale named the Maria Prehospital Stroke Scale (MPSS) by modifying the Cincinnati Prehospital Stroke Scale. Our objective is to evaluate its utility in a citywide bypass transportation protocol for intravenous (IV) tissue plasminogen activator (tPA). In the MPSS, facial droop, arm drift, and speech disturbance are tested by emergency medical technicians (EMTs). Facial droop is graded as normal (0) or abnormal (1), and the other 2 items are graded in 3 levels as normal (0), not severe (1), and severe (2). Thus, the total MPSS score ranges from 0 to 5. The predictive value of MPSS for thrombolytic therapy after bypass transportation was evaluated in 1057 patients. The MPSS scored by EMTs was significantly correlated with the National Institutes of Health Stroke Scale score in the emergency room (Spearman rho = .67, P = .000). The onset-to-door time was significantly longer with a low MPSS score (analysis of variance, F5,4.21 = .001). The rate of thrombolytic therapy was increased when the MPSS score increased from 0 to 5: 0%, 4.1%, 8.8%, 13.0%, 20.3%, and 31.5%, respectively. The areas under the receiver operating characteristic curve for the correct diagnosis of stroke and prediction of IV tPA therapy were calculated as .737 (95% confidence interval [CI]: .688-.786) and .689 (95% CI: .645-.732), respectively. Multivariate logistic regression analysis showed that the MPSS score and the detection-to-door time were independent predictors of tPA use after transportation. The MPSS is a novel prehospital stratification tool for the prediction of thrombolytic therapy after transportation.

[Extradural en bloc removal and in situ replacement of the anterior clinoid process].

Extradural removal of the anterior clinoid process (ACP) is useful and essential for approaching aneurysmal and tumor lesions in and around the cavernous sinus. A safe, rapid and less invasive technique is beneficial for this basic skull base surgery. We developed a new technique by sharply cutting the ACP together with the part of the sphenoid ridge bone followed by complete replacement. A series of patients with either basilar top or internal carotid artery aneurysms underwent the present technique. After frontotemporal craniotomy, the lateral frontal and anterior middle cranial fossae are exposed extradurally. The bone was cut using a cutting steel burr from the sphenoid ridge to the superior orbital fissure and to the optic canal. By sharply separating the meningo-orbital band between the dura propria and the periorbital fascia, the ACP is exposed. The cutting burr runs underneath the ACP. By leaving a very thin sheet of bone, the entire bone piece was elevated after fracturing the thin bone using a chisel. By severing the carotid ring, the internal carotid artery is freed and mobile either laterally or medially to obtain an ample basal cistern. After operation, the once removed clinoid process is replaced in situ using a titanium plate screw. Extradural en bloc removal and in situ replacement of the ACP can be safely done by this cutting procedure. This can provide a good cosmetic result without causing enophthalmos or transient oculomotor palsy.

Drainage or packing of the sella? Transsphenoidal surgery for primary pituitary abscess: report of two cases.

The detailed surgical procedure of the transsphenoidal surgery for pituitary abscess has scarcely been described previously because it is a very rare clinical entity. The authors reported two cases of primary pituitary abscess. In case 1, the anterior wall of the sella turcica was reconstructed with the vomer bone after irrigating the abscess cavity, but the sella was not packed by fat for fear of the persistent infection by devascularized tissues. This led to the postoperative meningocele, the cerebrospinal fluid leak, and bacterial meningitis despite the successful abscess drainage. In case 2, tight sellar packing and reconstruction of the sellar wall were performed to avoid these postoperative complications, which resulted in complete drainage and uneventful postoperative course. Although accumulation of more cases is obviously needed to establish the definitive surgical technique in pituitary abscess surgery, our experience might suggest that packing of the sella is not impeditive for postoperative sufficient drainage.

[Transposition technique of microvascular decompression for hemifacial spasm without using a brain retractor].

A unique transposition technique in microvascular decompression for hemifacial spasm (HFS) was employed in patients with compression by either the peripheral artery or the main trunk of the vertebral artery. Complete transposition that secured free space between the offending artery and the root exit zone (REZ) was accomplished by introducing GORE-TEX tape around the artery and suturing it to the petrous dura. An adequate working space, as if operating in a shallow basin, was essential. Throughout the procedure, it was not necessary to use a brain retractor. Instead, a gentle wrapping retraction technique using a sucker was employed over the brain covered by a sheet of Gelfoam (Pfizer Japan Inc., Tokyo) and cotton. All patients showed complete cure of HFS immediately after surgery with this technique. The difficulty of transposing the vertebral artery can be overcome by well-designed surgical strategy and skillfulness.

[A case of pial single-channel cerebral arteriovenous fistula].

A 60-year-old man presented with dizziness, dysarthria, and right hemifacial palsy with sudden onset. Computed tomography scan revealed a small cerebellar hematoma near the left flocculus. Since the site of the hemorrhage was atypical for cerebellar hemorrhages, emergency angiography was performed and revealed a pial single-channel arteriovenous fistula (AVF) in the early arterial phase with drainage into the dilated perimedullary vein. The feeding artery was a peripheral branch of the left anterior inferior cerebellar artery. There were no angiographical findings indicating a nidus or capillary network. The patient underwent left lateral suboccipital craniotomy. A small dilated perimedullary vein and an abnormally red spherical varix were found during the operation. A peripheral branch of the left anterior inferior cerebellar artery was thought to be a feeder because it seemed to be firmly attached to the dilated vein. Based on the operative technique for dural AVFs, electrocoagulation of the varix was performed aiming at obliteration of the fistula. The postoperative angiogram demonstrated the obliteration of the fistula and of the early filling vein. Feeders of cerebral AVF are cerebral arteries. A pial single-channel AVF is defined as a vascular malformation with a single venous channel in communication with one or more arteries with no intervening nidus or vessels. To date, reports in the literature of cerebral arteriovenous fistula have been very few. Its clinical entities such as origin, bleeding rate and the necessity of surgery remain subjects of debate. Here we report our experience and discuss its issues of the treatment we used.

Tilting operating table with self-control foot switch: a new neurosurgical tool.

BACKGROUND: Observation of the surgical field from all directions is essential in microneurosurgery. A tilting operating table operated by the surgeon can satisfy this need. METHODS: A tilting operating table operated by the surgeon using a foot switch was developed by modifying the Sugita table incorporating the X-Y shifter. RESULTS AND CONCLUSIONS: The modified operating table allows the surgeon to move the patient in the head up or down directions, as well as the left side down or right side down directions, so the surgical field can be inspected from all aspects without changing the vertical axis of the operating microscope.

Snare technique of vascular transposition for microvascular decompression--technical note.

Recurrence of trigeminal neuralgia (TN) or hemifacial spasm (HFS) after microvascular decompression (MVD) is not rare. The prosthesis material eventually adheres to the neurovascular structures and again transmits arterial pulsation to the nerve. A snare ligature technique using a Gore-Tex tape can be used for the transposition of the offending artery. No prosthesis is necessary once the transposition is complete. This technique requires introduction of either Gore-Tex tape or thread around the artery and suture over the petrous dura, so an adequate working space as if operating in a shallow basin is essential. Therefore, the osteoplastic craniotomy is a little larger than usual with the scalp flap entirely reflected using a semicircular skin incision. The Gore-Tex tape can be directly snared around the artery and sutured over the petrous dura. If this procedure is difficult, a thread can be attached to both ends of the Gore-Tex tape to pass the tape around the vessel. Seven patients with TN and 13 patients with HFS have undergone this surgery. Although the follow-up period is not yet long enough, there has been no case of recurrence. The present technique for MVD can provide complete and permanent transposition of the offending artery.

[Surgery of AVM of the inferior medullary velum by the uvulotonsillar approach--advantage of moving of the cerebellar tonsil: technical case report].

An incidentally found arteriovenous malformation (AVM) of the inferior medullary velum behind the medulla was removed by the lateral approach to the fourth ventricle originally described by Seeger in 1980. A wide posterior fossa craniotomy was performed to move the cerebellar tonsil laterally with C-1 laminectomy. The tela chroidea and inferior medullary velum, the two main sheets of tissue that form the lower half of the roof of the fourth ventricle can be exposed by gently displacing the tonsils laterally without splitting the vermis. Both the cerebellomedullary and uvulotonsillar spaces were exposed. Because the lateral cerebellomedullary cistern was also exposed, the moving of the cerebellar tonsil in a lateral direction was easy to do without injuring the cerebellar tissues. The nidus was located mainly in the extrapial plane that received feeding arteries from the posterior inferior cerebellar artery. The nidus was removed in a dry field without bleeding. This report is the first report of surgical removal of unruptured AVM of the inferior medullary velum through the so-called telovelar or transcerebellomedullary fissure approach. We propose to call this approach the uvulotonsillar approach to emphasize the dissecting plane between the uvula and the tonsil.