Hiromu Segawa

Radiosurgery of Meningeal Melanocytoma

The authors present a case of meningeal melanocytoma arising from Meckels cave. A coal-black, vascular tumor was partially removed by surgery. Histopathologically, the tumor lacked anaplastic features. Immunohistochemical studies confirmed that the tumor was of neuroectodermal origin and had low proliferating activity. The patient underwent gamma knife radiosurgery for the residual tumor, in which 25 Gy of radiation was delivered to the tumor margin. Three years after irradiation, the tumor showed marked shrinkage without complication.

Parasellar Aspergillus granuloma extending from the sphenoid sinus: report of two cases.

BACKGROUND Sphenoid sinus aspergillosis is a rare disease known to show an aggressive course with high mortality. Early diagnosis, though difficult, is required to prevent lethal fungal meningoencephalitis. CASE REPORT We describe two cases of parasellar Aspergillus granuloma extending from the sphenoid sinus clinically indistinguishable from intracranial neoplasms. In the first patient, the fungus colony was visualized by computed tomography (CT) and magnetic resonance imaging (MRI) as a calcified concretion and total removal was curative. In the second patient, partial removal and subsequent antifungal therapy had minimal effect. CONCLUSIONS The prognosis of the patients with this disease depends on prompt surgical treatment before intradural invasion occurs, and CT and MRI are useful diagnostic maneuvers for detecting calcified Aspergillus colonies.

Postoperative prognosis of Brown-Séquard-type myelopathy in patients with cervical lesions

BACKGROUND Postoperative prognosis of the hemihypalgesia in patients with Brown-Séquard-type myelopathy (BSM) caused by cervical lesions is of great interest to surgeons. However, there are very few reports discussing the postoperative prognosis of BSM. METHODS We evaluated the prognosis of BSM using the criteria of the Japanese Orthopaedic Association (JOA) score in 16 (seven ossification of the posterior longitudinal ligament [OPLL], 5 cervical spondylosis [CS], and 4 disc herniation patients) out of 233 surgically treated patients with cervical diseases. The mean follow-up duration was 2 years and 11 months. RESULTS After surgery, none of these patients showed complete resolution of hemihypalgesia, although the most rostral level of hemihypalgesia moved in a caudal direction in 13 patients (81%), whose recovery ratios of JOA score were significantly better than those of hemihypalgesia-level-persisted patients. In our BSM series, OPLL occurred most frequently and the anterior element compressing the spinal cord existed most frequently in the central area of the vertebra (44%). Postoperative improvement in the motor function of the legs in the disc herniation group was significantly better than in the OPLL and CS groups (p < 0.05, respectively). There were no significant differences in the functional prognosis between the BSM and non-BSM patient groups. CONCLUSIONS BSM patients can expect almost the same functional outcome as non-BSM patients, with the exception of the disappearance of hemihypalgesia.

Delayed Parent Artery Narrowing Occurring Months after Aneurysm Surgery

The authors report two patients with a rare complication of parent artery narrowing that occurred 3 and 6 months after aneurysm surgery. In both cases, the stenosed arteries had been wrapped around their entire circumferences with neurosurgical sponge (cotton linter) and coated with plastic adhesive (cyanoacrylate compounds) and the aneurysmal neck had been clipped. This reinforcement procedure was considered to have caused the unusual delayed arterial narrowing. The importance of avoiding circumferential parent artery wrapping with plastic-adhesive coating is emphasized.

Tomographic cerebral blood flow measurement using xenon inhalation and serial CT scanning: Normal values and its validity

Information concerning regional cerebral blood flow is not only essential to comprehend the haemodynamics of cerebral vascular disease, and to assess the effect of treatment for it, but is also useful for understanding the pathophysiology of other brain diseases. To date ~/-ray-emitting isotope (133Xe) technique has been widely used [1], and positron method has also been developed and clinically used in a limited number of institutions [2, 3, 4, 5]. However both methods have technical difficulties in obtaining quantitative estimation of blood flow and images of blood flow distribution with reasonable resolution.

Preoperative and postoperative magnetic resonance imaging (MRI) findings of radiculomeningeal arteriovenous malformations: Important role of gravity in the symptoms and MRI

BACKGROUND The symptoms of radiculomeningeal arteriovenous malformations (AVMs) are reported to be uniform, which suggests it to be a conus medullaris syndrome, and in fact, the lesions on magnetic resonance imaging (MRI) images usually include the conus medullaris. However, the reason why the conus medullaris is always involved in the lesion has not been discussed. METHODS We encountered seven patients with spinal radiculomeningeal AVMs and operated on all of them. We evaluated the preoperative and postoperative MRI findings in these patients. Postoperative MRI was followed ranging from 6-32 months (mean: 21 months) after surgery. RESULTS All of our patients showed swelling of the spinal cord, including the conus medullaris, on the preoperative magnetic resonance image. Postoperatively, MRI showed that the swelling of the spinal cord had resolved but that it had finally deteriorated into an atrophic condition. In all of five patients who could be followed up using multiple postoperative MRI scans, sequential T2-weighted images showed that the most rostral level of areas with increased signal in the spinal cord moved in a caudal direction with time. CONCLUSIONS This and the fact that the conus medullaris was included in the swelling of the spinal cord regardless of the level of the nidus in all our patients, suggested that gravity played an important role in the etiology of radiculomen-ingeal AVM in these patients.

Functional prognosis after treatment of spinal dural arteriovenous fistulas.

We statistically evaluated the functional outcome after surgery or embolization therapy of 43 patients with spinal dural arteriovenous fistula including 10 patients of our own and 33 previously reported cases in the literature. This study prompted us to consider that a patient under 70 years old who is treated within 2 years 6 months after the onset of symptoms and whose gait or urinary disturbance is slight or moderate without absence of deep tendon reflexes in the lower extremities is expected to get a good functional prognosis after treatment.

Microsuture-tying forceps with attached scissors for bypass surgery.

BACKGROUND Bypass surgery requires the shortest temporary occlusion time of a recipient artery during anastomosis. For this purpose, we have devised a microforceps with attached scissors that makes it possible to perform the multiple steps involved in anastomosis without exchanging instruments. This microforceps avoids having to exchange instruments twice in one suturing, such as that between a microsuture-tying forceps or a microneedle holder and microscissors in conventional methods. METHODS The instrument is made of stainless steel and is 15.5 cm long. Using this microforceps with scissors, we can suture, tie, and cut a ligature fluently for consecutive sutures without exchanging instruments. The mean time during one suturing was compared between two patient groups treated by conventional method and with use of this instrument. RESULTS This instrument was used for 34 patients with ischemic cerebrovascular disease (including three who needed deep-site anastomoses) and allowed us to perform superficial temporal artery-middle cerebral artery (STA-MCA) anastomoses uneventfully. This instrument saved 15.2 s in the mean time during one suturing. CONCLUSIONS Although it is of paramount importance to practice tying sutures well, this new instrument removes the need to exchange conventional instruments, and we believe it will save time and, therefore, decrease complications during bypass surgery.

Brain stem haemorrhage during transsphenoidal surgery: Possible risk of the manoeuvre of increasing the endexpiratory pressure in a case of pituitary adenoma associated with dural arteriovenous malformation. Case report

SummaryThe authors report a case of pituitary adenoma associated with dural arteriovenous malformation (AVM), which caused brain stem haemorrhage during transsphenoidal surgery. The manoeuvre of increasing the endexpiratory pressure in order to push the suprasellar component of the adenoma down to the sella turcica could be the reason of this bleeding. The authors therefore recommend that in cases of such a combination any manoeuvres which are likely to increase the intracranial venous pressure or otherwise affect the intracranial pressure, are avoided. The dural AVM spontaneously regressed after haemorrhage.