The present study conducted risk-adjusted analyses to investigate the impacts of hospital and surgeon volumes on postoperative complications and the modified Rankin scale (mRS) after intracranial clipping of unruptured aneurysms, and to discuss the efficacy of relevant policy changes. Among 107 Japanese institutions, physician-reported data for 702 unruptured aneurysm patients were registered between December 2006 and April 2007. Postoperative complications and the mRS at the time of discharge were independently regressed against hospital and surgeon volumes, aneurysm size, aneurysm location, and comorbidities. Aneurysm size was a significant predictor of the overall outcomes. After adjusting for prominent confounders, hospital volume did not show any significant associations with postoperative complications (odds ratio [OR] 0.75, 95% confidence interval [CI] 0.34-1.68, p = 0.49) or the mRS (OR 0.60, 95% CI 0.19-1.93, p = 0.39). Higher surgeon volume (≥100) was associated with lower mRS scores (OR 0.40, 95% CI 0.20-0.83, p = 0.013), but had no significant relationship with postoperative complications (OR 0.72, p = 0.47). Our risk-adjusted analyses showed no significant relationships between hospital volume and comorbidities. Therefore, the justification for hospital volume-based policies remains unclear. Prospective risk-adjusted volume-based studies are required for future evidence-based referral policies.
The present study evaluated the effect of the free radical scavenger edaravone on lesion volume and neurological dysfunction after spinal cord injury (SCI) in mice, and investigated its protective effects on superoxide generation. Female C57BL/6 mice were subjected to SCI using a pneumatic impact device and were treated with 3 mg/kg of edaravone or vehicle 30 minutes before the insult. Motor functions were quantitatively evaluated. Lesion volume was assessed by Dohrmann’s two-cone method after one week. In situ detection of superoxide in the injured cord was carried out using the superoxide-sensitive dye dihydroethidium (DHE) staining technique. Pretreatment with edaravone significantly improved motor dysfunction and reduced the lesion volume to about 63% of the control (p < 0.05). Semi-quantitative measurements of red fluorescence emitted from DHE revealed that the superoxide concentration increased in the lesion periphery at 1 and 3 hours after the insult, and that pretreatment with edaravone significantly inhibited the increase of superoxide concentration in the lesion periphery at both time points (p < 0.0001). Double staining with DHE and monoclonal antibody against MAP2 showed that most cells positive for DHE were also positive for MAP2. These findings suggest that edaravone ameliorates tissue damage by scavenging reactive oxygen species, especially in the neurons, after SCI.
The long-term efficacy of resective surgery was investigated in patients with lesions detected by magnetic resonance (MR) imaging. Thirty of 47 patients who had undergone lesionectomy between 1987-2001 were followed up by questionnaire. Patients with extratemporal resections outnumbered those with temporal lobe resections. The mean follow-up period was 12.4 ± 3.7 years. Outcomes were graded according to Engel’s criteria, and an arbitrary seizure outcome score was given for quantitative assessment. The mean seizure outcome scores were significantly lower in the early childhood (less than 3 years) onset group than in the late childhood (3 to 15 years) onset group, and significantly lower in the extratemporal resection of the cortical dysplasia group than in the temporal resection and the extratemporal resection of non-cortical dysplasia groups. This study indicated that lesionectomy based on MR imaging findings in patients with intractable epilepsy achieved effective long-term seizure control, and the outcome was related mainly to the pathology of the epileptogenic lesions and the temporal or extratemporal location.
The safety and effectiveness of the minimum incision technique were assessed in 138 hands of 108 consecutive patients with carpal tunnel syndrome treated from April 1, 1997 to March 31, 2006. Clinical and electrophysiological examinations were conducted before and after surgical decompression. All hands were divided into early, mild, moderate, and severe groups based on preoperative electrophysiological severity. We examined the surgical outcomes of the affected hands in each group. Nocturnal or daytime dysesthesia, which had been present in 132 (96%) of the 138 hands preoperatively, was completely relieved in 124 (94%) of the 132 hands. Complete relief was achieved in 7 (100%) of the 7 hands in the early group, 68 (99%) of the 69 hands in the mild group, and 45 (94%) of the 48 hands in the moderate group. Complete relief was achieved only in 4 (50%) of the 8 hands in the severe group, and 3 (38%) of the 8 hands did not show any improvement. No painful or hypertrophic scar formation was observed in this series. Only 2 patients complained of postoperative scar discomfort after more than 12 months, which completely disappeared by 14 months after surgery. Minimum incision open carpal tunnel release is a safe and reliable procedure with a high rate of functional improvement and patient satisfaction. Postoperative results were satisfactory regardless of the degree of preoperative electrophysiological severity if preoperative sensory nerve action potentials were detected.
Three of 4 cases of dural arteriovenous fistulas (DAVFs) in the anterior cranial fossa were detected incidentally by magnetic resonance (MR) imaging, and one case manifested as intracerebral hemorrhage. Cerebral angiography revealed fistulas located in the anterior cranial fossa. Three patients underwent surgery, and the fistulas were successfully obliterated. One patient with nonruptured DAVF requested conservative medical management. Incidental detection of asymptomatic or nonruptured DAVFs in the anterior cranial fossa has increased with the wider use of MR imaging. Increase in the size of a venous varix is the indicator for aggressive therapeutic intervention in a patient receiving conservative medical management for asymptomatic or nonruptured DAVFs in the anterior cranial fossa.
A 60-year-old man presented with transverse sinus dural arteriovenous fistula (AVF) manifesting as sudden onset of headache and nausea, which underwent spontaneous closure 5 years after the onset. Computed tomography on admission revealed small intraventricular hemorrhage in the right lateral ventricle. No intracranial vascular lesion was detected and magnetic resonance angiography was used at yearly follow up. Two years after the first admission, he suffered diplopia and cerebral angiography revealed transverse sinus dural AVF. Right pulsatile tinnitus occurred 4 years after the first admission. The symptoms suddenly disappeared 5 years after the first admission, and follow-up angiography showed disappearance of the dural AVF. The exact mechanism of the spontaneous occlusion of dural AVF remains unknown. This case of spontaneous transverse sinus dural AVF closure occurred without disruption of sinus patency, suggesting that thrombosis of the draining veins into sinuses was not involved.
A 37-year-old woman presented with a rare cavernous malformation of the ventral midbrain with brainstem hemorrhage manifesting as sudden onset of headache and vomiting. The lesion was removed successfully through a transsylvian approach and a medial peduncular route. Postoperatively, her oculomotor nerve paresis worsened temporarily, but diplopia disappeared 2 months after surgery. We recommend the transsylvian-transpeduncular approach if the lesion is located in the ventral midbrain and faces the ventral surface of the brainstem, because of the effective access with minimal neurological deficits.
A 20-year-old man presented with a rare case of germinoma with a large component of epithelioid cell granuloma manifesting as oscillopsia. Magnetic resonance imaging demonstrated a mass in the pineal region with homogeneous enhancement with gadolinium. Craniotomy was performed, ending in biopsy. The initial histological diagnosis was epithelioid cell granuloma, but systemic investigation detected no evidence of granulomatous disorder. A revised diagnosis of germinoma was based on positive immunohistochemical staining for placental alkaline phosphatase (PLAP) and c-kit. Histological diagnosis is sometimes incorrect if granulomatous reaction is dominant. Immunohistochemical staining for PLAP and c-kit should be performed if germinoma is clinically suspected.
A 22-year-old female first presented with a fibrillary astrocytoma in the left temporal region manifesting as complex partial seizure. She underwent left temporal craniotomy to remove the tumor. Surgery was uneventful, but she began to experience a blocked feeling in the left ear after surgery. Computed tomography (CT) obtained 3 weeks after surgery revealed persistent extradural air collection, which developed into an enlarged extradural air mass on follow-up CT obtained 8 months after surgery. She underwent additional surgery for obliteration of the pneumatocele by sealing the mastoidal fenestration with abdominal fat. She reported resolution of the symptom postoperatively. Extradural pneumatocele following temporal craniotomy is extremely rare, but is a possible surgical complication of opening of the mastoid sinuses.
A 52-year-old female presented with extraforaminal lumbar synovial cyst at the L4-5 level causing sudden foot drop on the right. Computed tomography, magnetic resonance (MR) imaging, and coronal MR myelography source images identified the cystic mass in the extraforaminal zone. The patient underwent microdecompression via a lateral transmuscular route, and the extraforaminal cyst compressing L4 ganglion was successfully removed. The histological diagnosis was synovial cyst. This unique case of surgically proven extraforaminal lumbar synovial cyst causing sudden foot drop indicates that extraforaminal synovial cyst should be included in the differential diagnosis of patients presenting with sudden foot drop.
Experience with dissection of the cavernous sinus and the temporal bone is essential for training in skull base surgery, but the opportunities for cadaver dissection are very limited. A modification of a commercially available prototype three-dimensional (3D) skull base model, made by a selective laser sintering method and incorporating surface details and inner bony structures such as the inner ear structures and air cells, is proposed to include artificial dura mater, cranial nerves, venous sinuses, and the internal carotid artery for such surgical training. The transpetrosal approach and epidural cavernous sinus surgery (Dolenc’s technique) were performed on this modified model using a high speed drill or ultrasonic bone curette under an operating microscope. The model could be dissected in almost the same way as a real cadaver. The modified 3D skull base model provides a good educational tool for training in skull base surgery.