Motoki Baba

The Edinburgh-2 Coma Scale: A New Scale for Assessing Impaired Consciousness

In the management of patients with acute cerebral disturbances, it is essential to determine precisely the degree of impaired consciousness. However, a coma scale for assessing impaired levels of consciousness has not yet been standardized internationally. The Edinburgh-2 coma scale (E2 CS) is introduced and compared with the Glasgow coma scale (GCS). The reliability of the E2 CS was tested by comparing levels of the E2 CS with the outcome of patients who underwent neurosurgical operations. A good correlation was observed between the levels of the E2 CS and the outcome. A change of two levels suggests that some change influencing the outcome has occurred or exists within the cranium of the patient. A correlation between the E2 CS and the GCS was proven to exist. The merits and drawbacks of both scales are discussed. One advantage of the E2 CS is that it has removed ambiguous terms, which are still present in the GCS. Also it is easier to grasp changes in a patients condition shown on a chart because the levels of the E2 CS are arranged first-dimensionally. Use of the GCS should not preclude the use of other scales, such as the E2 CS; the E2 CS could be used together with the GCS. The accumulation of data on both scales would provide information useful in improving the existing coma scales.

Chiari I malformation associated with ventral compression and instability: one-stage posterior decompression and fusion with a new instrumentation technique.

OBJECTIVE AND IMPORTANCE:We describe an alternative surgical technique for treatment of Chiari I malformation associated with ventral compression and instability of the region. An expansive suboccipital cranioplasty and a rigid occipitocervical fixation are performed in one stage. METHODS:The occipitocervical fixation is performed by use of metal rods fixed on the cranial side by screws inserted into the diploic layer of occipital bone and on the caudal side by screws inserted into the pedicle of the axis or in a transarticular fashion into the lateral masses of axis and atlas vertebra. A large piece of autologous bone is placed in the region between the rostral edge of cranial decompression and the axis, with the aim of achieving both expansive suboccipital cranioplasty and occipitocervical fusion. RESULTS:We performed this procedure in two patients with Chiari I malformation associated with basilar invagination and occipitalization of the atlas. Postoperatively, decompression of the brainstem and restoration of normal cerebrospinal fluid flow at the craniovertebral junction were confirmed radiologically, and the patients were relieved of their symptoms. At 1 and 3 years of follow-up, respectively, solid bone fusion was observed between the occipital bone and axis in both patients. CONCLUSION:Simultaneous posterior decompression and occipitocervical fixation with an alternative instrumentation technique is discussed. The procedure can be performed regardless of the size of suboccipital craniectomy. Screw insertion into the diploic layer of the occipital bone has not been described previously.

Structural mechanics of the blowout fracture: numerical computer simulation of orbital deformation by the finite element method.

Blowout fractures most frequently involve the orbital floor. The contour of the orbit has been postulated as one of the factors responsible for this phenomenon, but only a few studies have been carried out. The present study was planned to determine the effect of the contour of the orbit when intraorbital pressure is raised to simulate the hydraulic mechanism of blowout fracture. The profile of the orbit was estimated from five dry human skulls, and the measurements were approximated to frame models. The deformation of these models by raised intraorbital pressure was calculated by computer simulation using the finite element method. In all of the orbital models, the deformation of the orbital floor was significantly greater than that of the roof. These findings verified that the orbital roof has a higher resistance than the floor against raised intraorbital pressure. We suspect that this resistance is due to the arched shape of the orbital roof, whereas the floor is rather flat.

Parasellar chondroma: A case report

A case of a 19-year-old man with a right parasellar chondroma examined with computed tomography (CT) and nuclear magnetic resonance (NMR) scan is reported. The literature about CT and NMR scan findings of intracranial chondroma is reviewed. Typical CT findings are a round, high density mass with calcification, that is only slightly enhanced by contrast medium.

Contralateral approach to junctional C2-C3 and proximal C4 aneurysms of the internal carotid artery: microsurgical anatomic study.

OBJECTIVE To evaluate a contralateral approach to aneurysms located in the internal carotid artery cave and proximal C4 segments. METHODS In six adult cadaveric head sides, proposed aneurysms in the carotid cave or proximal C4 segments were approached via contralateral craniotomies. We summarize the approach in the following steps: 1) frontotemporal orbital craniotomy, 2) drilling of the lateral sphenoid wing and opening of the dura along the frontotemporal base, 3) drilling of the planum sphenoidale and the tuberculum sellae more extensively toward the aneurysm side and opening of the sphenoid sinus, 4) drilling of the medial part of the anterior clinoid process on the side of the aneurysm and removal of the superior, medial, and inferior walls of the optic canal, 5) opening of the optic sleeve, and 6) opening of the space between the medial wall of the internal carotid artery C2-C3 segments and the lateral edge of the pituitary gland. RESULTS The contralateral approach to expose the opposite internal carotid artery cave and proximal C4 segments provided excellent views of the region, without mobilization or retraction of either the optic nerve or the carotid artery. CONCLUSION We recommend that this approach be used only for selected aneurysms, which are small and directed medially, anteriorly, or inferiorly, in the defined locations.

Intracranial pressure monitoring by a subdurally placed silicone catheter: technical note.

A silicone catheter manufactured originally for ventricular fluid drainage was used for continuous monitoring of intracranial pressure. It can be placed under the dura mater immediately before replacing the craniotomy flap or by introduction through an ordinary burr hole. Pressure is monitored isovolumetrically by connecting the catheter to a pressure transducer mounted at the bedside. This technique has been used in 34 neurosurgical patients for periods of up to 12 days without any untoward effects. This monitoring system by a subdurally placed silicone catheter is simple, safe, inexpensive, and acceptably reliable. It has a place in clinical practice, particularly when the lateral ventricle cannot be tapped because of its deviation or collapse.

A simple fluid collection system for neurosurgical operations

A simple and inexpensive fluid collection bag system for neurosurgical operations is described. It is quite satisfactory for preventing operators from soiling their feet and their gowns.