Multiple Synchronous Spinal Dural Arteriovenous Fistulas: A Systematic Literature Review

BACKGROUND AND OBJECTIVES

Spinal dural arteriovenous fistulas (SDAVFs) lead to progressive neurological decline with symptoms such as paraparesis, bowel and bladder dysfunction, and sensory disturbances because of impaired spinal cord venous drainage. This study aimed to systematically review the literature on multiple synchronous SDAVFs and present 2 cases from our institution.

METHODS

A comprehensive search was performed to identify all published cases of multiple synchronous SDAVFs. Overall, 23 patients with multiple synchronous SDAVFs were identified, including 21 from 19 articles and 2 from this study. The clinical presentation, lesion location, radiographic features, surgical treatment, and outcomes were analyzed in each patient.

RESULTS

All patients in this study were male, and the duration from symptom onset to diagnosis in many of these patients was longer than that previously reported. Previous studies suggested that multiple SDAVFs typically occurred within 3 or fewer vertebral levels. However, >50% of the examined patients had remote lesions separated by more than 3 vertebral levels. Patients with remote lesions had a significantly worse outcome (1/7 vs 8/11, 95% CI 0.001-0.998; P = .049).

CONCLUSION

Accurately locating fistulas before spinal angiography is critical for managing multiple remote SDAVFs. Considering the possibility of multiple remote SDAVFs, careful interpretation of imaging findings is essential for an accurate diagnosis and appropriate treatment planning.

MPC-16 CHARACTERISTICS AND PROGNOSTIC FACTORS OF H3K27M-MUTANT DIFFUSE MIDLINE GLIOMA

H3 K27M-mutant diffuse midline gliomas (DMG) is a still challenging disease with no effective medical therapies. We analyzed the characteristics and prognostic factors of 64 patients with midline gliomas including 18 patients with H3 K27M-mutant DMG treated in Kobe University Hospital from 2006 to 2021. The median age at diagnosis in midline gliomas was 50.1 years (range: 14-82 y). All tumors were located in thalamus n=25, corpus callosum n=8, brainstem n=8, spinal cord n=6, cerebellum n=15, and pineal region n=2. Isocitrate dehydrogenase 1 (IDH1) and H3 K27 mutation was recognized in 6 and 18 patients, respectively, which was mutually exclusive. In all midline gliomas, the identification of an H3 K27M mutation was significantly a poor prognosis factor (median 19.8 months vs 27.9 months, p=0.042). Compared to midline gliomas without histone H3 and IDH1 mutations (IDH1/H3 wild type), however, H3 K27M-mutant DMG had no worse overall survival (median 19.8 months vs 15.9 months, p=0.51). H3 K27M-mutant DMG is considered as a distinct WHO Grade 4 regardless of histological features, but the biological properties of H3 K27M mutation is not yet defined in IDH1 wild-type midline gliomas.

Acute Occlusion of the Ventriculoperitoneal Shunt Due to Factor XIII Deficiency-related Postoperative Hemorrhage: A Case Report

Coagulation factor XIII (F13) deficiency has been known to be a rare disease with estimated one per two million and one of the possible reasons of postoperative hemorrhage; however, it still remains unpenetrated to physicians. We report a case of acute ventriculoperitoneal (VP) shunt dysfunction due to delayed intraventricular hemorrhage, which could be because of F13 deficiency. The patient was a 48-year-old man with a history of post-meningitis hydrocephalus followed by VP shunt placement. He was found unconscious and transferred to our hospital. A brain CT scan demonstrated shunt malfunction, and he underwent emergency shunt revision. The postoperative course was uneventful except for unexpected neck bruises and continuous minor bleeding from the surgical wound. Three days after surgery, he suddenly became comatose and a CT scan revealed the recurrence of hydrocephalus with newly identified small volume of intraventricular hemorrhage. Emergency shunt revision was performed again. The shunt valve was filled with a hematoma and bloody cerebrospinal fluid was drained from the ventricle. Postoperative blood sample examination demonstrated no abnormal findings but a decreased level of F13 activity, which was thought to be a possible cause of postoperative hemorrhage and the shunt valve hematoma. F13 deficiency causes delayed intracranial hemorrhage 24–48 h after neurological surgery. It can only be diagnosed by checking F13 activity with suspicion. If diagnosed accurately beforehand, unexpected postoperative bleeding can be preventable with proper treatment, such as F13 concentrate and cryoprecipitate. The actual number of the patient with F13 deficiency may be more than estimated ever.

[Posterior Approach for Cervical Spondylotic Myelopathy in Patients Older than 80 Years of Age]

OBJECTIVE

We aimed to investigate the characteristics and operative results of elderly patients with cervical spondylotic myelopathy(aged ≧80 years)treated using the posterior approach.

METHODS

Between April 2010 and December 2018, 21 patients aged ≧80 years(older group:8 men and 13 women;age range, 80-90 years)who underwent laminoplasty were reviewed and compared with 23 patients aged <80 years(younger group;13 men and 10 women;age range, 42-79 years)who underwent laminoplasty. The following data were obtained from chart reviews:age;sex;cervical canal stenosis level;time to operation;symptoms(e.g., gait disturbance);comorbidities(hypertension, diabetes mellitus, cancer, heart disease, ischemic cerebrovascular disease, and lumbar canal stenosis);antithrombotic drug use;cardiac, pulmonary, and renal functions;operative time;volume of blood loss during the operation;postoperative delirium;and follow-up period. Neurological deficits before and after the surgery were assessed using the neurosurgical cervical spine scale(NCSS). Data were statistically analyzed, and p-values <0.05 were considered statistically significant.

RESULTS

The operative time, symptoms(hypertension), renal function, and preoperative NCSS score were significantly different between the older and younger groups. Meanwhile, most variables showed no significant differences between the groups. Although the preoperative NCSS score was lower in the older group, there was no significant difference in the degree of improvement in the NCSS score after surgery.

CONCLUSIONS

The findings of this study suggest that we should not hesitate to perform surgery for cervical spondylotic myelopathy in elderly patients with favorable cardiorespiratory function.

NQPC-09 PROGNOSIS AND DELAYED COMPLICATIONS OF MEDULLOBLASTOMA IN KOBE CHILDREN’S HOSPITAL

Medulloblastoma is the most common pediatric malignant tumor and about 84.2% of cases are under 15 years old. With a current combined-modality approach that includes surgical approach, chemotherapy and radiation therapy, 5 year-survival rates have become 70–85% and also the so-called long-term survivors have increased in our country. This report reviews the prognosis and delayed complications of medulloblastoma in our institute. Cases were 14 boys and 11 girls from January,2010 to May 2019. Mean age was 6.1 years old (4 months to 14 years old). 18 cases receiver gross total removal and 12 cases were high risk group. Exclude recent 4 cases, 15 cases have indicated complete reaction though 6 cases had relapsed or new tumor. The results are that 5 year-survival rates in our institute is 86.7%, but 4 cases had neuro-psychological complications. 5 cases suffered from endocrinal disorders which were not confirmed after the end of all treatments. 2 secondary cancer had appeared 5 and 8 years after the first treatments. The more the survivor in medulloblastoma cases increase, neurosurgeons have to consider long term follow up more than 5 years and pay more attention to support activity of daily life of these patients.

[Locked-in Syndrome due to Primary Brainstem Injury:A Case Report]

Most cases of the primary brainstem injuries(PBSI)are fatal, and disturbance of consciousness is often prolonged even if lifesaving is obtained. The mechanisms of PBSI are as follows: diffuse axonal injury from acceleration/deceleration, shear strain at the midbrain, direct injury of neurovascular structures by tentorial margin, and lower brainstem injury by hyperextension of the cervical vertebrae. Though we can use both CT and MRI to diagnose, MRI is more helpful than CT in detecting, localizing, and characterizing PBSI. When the location of PBSI is limited in the ventral side of pons, it may occasionally result in locked in syndrome(LIS). Generally it is difficult to diagnose LIS with severe trauma due to the rarity of this syndrome caused by head injury. Here, we report a case of an elderly man with traumatic brainstem hemorrhage, who transiently presented LIS and finally improved.

Delayed Rebleeding from Pseudoaneurysm After Mechanical Thrombectomy Using Stent Retriever Due to Small Artery Avulsion Confirmed by Open Surgery

BACKGROUND

Pseudoaneurysm after mechanical thrombectomy (MT) is rare but is one of the potential complications associated with endovascular procedures. There is limited information regarding its mechanism of formation and the potential risk of delayed bleeding.

CASE DESCRIPTION

An 84-year-old woman was admitted to our institution with right hemiplegia and global aphasia. Magnetic resonance imaging and angiography revealed occlusion of the M2 segment of the left middle cerebral artery with subtle acute ischemic change in this territory. After initiating intravenous thrombolysis, MT was performed for persistent occlusion of the M2. Successful revascularization was finally achieved with a single pass of a Trevo XP 3 mm × 20 mm stent retriever; significant deviation of the vessel occurred during withdrawal of the stent retriever. Anticoagulation was initiated after confirming resolution of a small amount of postprocedural subarachnoid hemorrhage 1 day after the procedure. However, 4 days after the procedure, computed tomography and angiography revealed a massive sylvian hematoma with de novo formation of a small pseudoaneurysm at the site where the stent retriever was deployed. Open surgery revealed a small artery avulsion at this site. The lesion was closed by microsurgical suturing.

CONCLUSIONS

Angiographic and intraoperative findings showed that the mechanism of formation of the pseudoaneurysm was small artery avulsion resulting from deviation of the vessel during withdrawal of the stent retriever. When performing MT in a tortuous distal vessel, the possibility of small artery avulsion should be kept in mind to both prevent and manage critical hemorrhagic complications.

[Visual outcome of macular hole surgery with internal limiting membrane peeling]

PURPOSE

To evaluate the efficacy of the internal limiting membrane(ILM) peeling on macular hole surgery.

METHODS

A series of 102 patients(105 eyes) who underwent primary macular hole surgery between October 1994 and April 1999 was used for this retrospective study. The mean age was 65.6 +/- 7.1 years (mean +/- standard deviation). Of the study eyes, 34 eyes(32%) had a Stage II hole, 49 eyes(47%) had a Stage III hole, and 22 eyes(21%) had a Stage IV hole based on the Gass classification. Here we compared the surgical and visual outcome of the ILM peeling-treated group(treated group: 51 eyes) with those of ILM peeling-untreated group(untreated group: 54 eyes).

RESULTS

The hole closure rate after initial surgery was 98.0% in the treated group and 90.7% in the untreated group, and mean postoperative visual acuity, excluding cases where the hole was not closed by initial surgery, was 0.44 and 0.47, respectively. Visual improvement of 2 or more lines on Snellen chart was achieved in 84.3% and 57.4%(p < 0.01), and that of 4 or more lines in 54.9% and 25.9% (p < 0.01), respectively. Of the eyes with Stage II and III holes, visual outcome of the treated group was significantly better than that of the untreated group(p = 0.034, p = 0.037). In Stage IV, the initial closure rate of the treated group was significantly better than that of the untreated group(p = 0.02), but the visual outcome was not significantly different.

CONCLUSION

Vitreous surgery combined with ILM peeling for the management of idiopathic macular hole is effective not only on hole closure but also on visual recovery.

Molecular characterization in the VP7, VP4 and NSP4 genes of human rotavirus serotype 4 (G4) isolated in Japan and Kenya

The VP7, VP4 and NSP4 genes of human rotavirus serotype 4 (G4) were analyzed to investigate intraserotypic variations. The techniques used included reverse transcription polymerase chain reaction with subtype specific primers, restriction fragment length polymorphism analysis and sequence analysis. Twelve isolates (nine from Japan and three from Kenya) and two standard strains (Hochi, Odelia) were G4A P[8] Wa group NSP4. A standard strain (ST3) was G4A P[6] Wa group NSP4 and a strain (VA70) was G4B P[8] Wa group NSP4. These results show G4 rotaviruses can be divided into three combinations at the moment.

Optical cross-sectional evaluation of successfully repaired idiopathic macular holes by retinal thickness analyzer

PURPOSE

To describe optical cross-sectional images of successfully repaired idiopathic macular holes and to determine the influences of epiretinal membranes and retinal pigment epithelial (RPE) changes on foveal reconstruction and the correlation between retinal thickness and postoperative visual acuity.

METHODS

In a prospective study, optical cross-sectional imaging and retinal thickness measurement of the macula using a retinal thickness analyzer were performed on 63 eyes of 63 patients who underwent successful macular hole surgery.

RESULTS

Cross-sectional images of foveal reconstruction were morphologically categorized into four patterns: normal fovea (23 eyes [37%]), cavernous fovea (19 eyes [30%]), flat fovea (11 eyes [17%]), and irregular fovea (10 eyes [16%]). Epiretinal membranes were observed in the last two groups (55% and 40%) and RPE changes were observed only in the irregular fovea group (16%). The mean retinal thickness of the fovea in all eyes was 213 +/- 92 microm (mean +/- SD; range, 93-570 microm), which varied significantly (P < 0.001) among the four groups. Linear regression analysis showed a significant correlation between retinal thickness at the fovea and logarithmic converted visual acuity (R2 = 0.42, P < 0.001).

CONCLUSIONS

Structural features of foveal reconstruction following successful macular hole surgery involved four patters: normal fovea, cavernous fovea, flat fovea, and irregular fovea. Retinal thickness of the fovea, which varied among the groups, correlated with postoperative visual acuity. Postoperative epiretinal membrane formation and RPE damage may disturb normal foveal reconstruction and visual recovery.

Two-year follow-up study comparing primary vitrectomy with scleral buckling for macula-off rhegmatogenous retinal detachment

PURPOSE

To compare the anatomic and visual outcomes achieved by scleral buckling and primary vitrectomy for the repair of macula-off rhegmatogenous retinal detachment.

METHODS

The records were reviewed for a consecutive series of 167 patients (167 eyes) who were initially treated with scleral buckling or pars plana vitrectomy for primary macula-off retinal detachment. Patients were treated between January 1993 and December 1996. After adjustments for preoperative characteristics, data from 102 cases (55 scleral buckle cases and 47 primary vitrectomy cases) were used for the final comparison. There had been a minimum follow-up period of 24 months.

RESULTS

No significant differences in single-procedure reattachment incidence (91%), final success incidence (100%) and incidence of postoperative proliferative vitreoretinopathy development (4%) were observed between the two treatment groups. Preoperative visual acuity, preoperative intraocular pressure, and duration of macular detachment were the three best predictors of postoperative visual recovery in both groups. Favorable overall visual recovery was obtained postoperatively, with no significant differences between the two groups throughout the follow-up period. However, in the eyes with poor preoperative visual acuity (<0.1), ocular hypotony (intraocular pressure <7 mm Hg), or prolonged macular detachment (more than 7 days), visual recovery in the primary vitrectomy group was significantly better (P <.05) than in the scleral buckle group from the first postoperative month.

CONCLUSION

Both procedures achieved favorable anatomic and visual outcomes in the majority of patients with primary macula-off retinal detachment. Primary vitrectomy may be more effective than scleral buckling for achieving early visual rehabilitation in cases complicated by poor preoperative vision, ocular hypotony, and prolonged macular detachment.

Phylogenic analysis of echovirus type 30 isolated from a large epidemic of aseptic meningitis in Japan during 1997-1998

During 1997 to 1998, a nationwide epidemic of aseptic meningitis occurred in Japan. More than 4,500 isolates from patients with aseptic meningitis were identified as echovirus type 30. To investigate the character of these isolates, we examined the nucleotide sequences of thirty-seven geographical representatives and compared them with 50 strains isolated during the past 20 years. The phylogenic analysis used partial sequences from either the VP1 or VP4-VP2 region of the viral capsid. This analysis revealed that the isolates were divided into six genomic groups. All isolates identified during 1997-1998 belonged to only two genomic groups; these two groups are thought to be the causative viral agents involved in the recent epidemic.

[Macular morphologic reconstruction and visual recovery in patients following macular hole surgery]

PURPOSE

To examine the characteristics of retinal reconstruction at the macula following macular hole surgery and to assess the impact of postoperative macular morphological changes on the visual outcome.

METHODS

A prototype of the scanning retinal thickness analyzer (RTA) was used to obtain optical section images at the macula in 53 eyes of 52 patients who underwent macular hole surgery between April 1994 and July 1997. The mean age of participants was 64.7 years. At the time of RTA examination, macular hole was biomicroscopically closed in 49 eyes (91%) and unclosed in 5 eyes (9%).

RESULTS

There were 5 types of cross-sectional images of postoperative maculae: normal foveal depression [19 eyes (36%)], crater-like fovea formation [12 eyes (22%)], flattened fovea [8 eyes (15%)], fovea with abraded retinal pigment epithelium [9 eyes (17%)], and persistant macular hole [5 eyes (9%)]. Central macular thickness measured by RTA was 165 +/- 39 (mean +/- standard dereation) microns in the normal foveal depression group, 210 +/- 67 microns in the crater-like fovea formation group, and 300 +/- 50 microns in the flatened fovea group. There were statistically significant differences (p < 0.01) between groups. Postoperative visual acuity was significantly different (p < 0.01) between these three groups, and central macular thickness was highly correlated with postoperative visual acuity (R = 0.70).

CONCLUSION

Visual recovery following macular hole surgery is closely associated with the retinal reconstruction at the macula.

Survey of surgical indications and results of primary pars plana vitrectomy for rhegmatogenous retinal detachments

BACKGROUND

Several surgical techniques to repair rhegmatogenous retinal detachment have been developed. Recently, both the method of reattaching the retina and of obtaining an early visual recovery are considered important factors when determining which surgical techniques to perform to treat retinal detachment.

CASES

The surgical outcome in a series of 63 consecutive patients, who were treated at Osaka Rosai Hospital between 1993 and 1996, was reviewed retrospectively to evaluate the efficacy of primary vitrectomy to treat uncomplicated rhegmatogenous retinal detachment associated with posterior hyaloid separation. The criteria for vitrectomy included the presence of not only posterior retinal breaks, but also of multiple peripheral retinal breaks.

OBSERVATIONS

The reattachment rate after the first surgery was 92.1% (58 eyes), and by the final examination it increased to 100%. Of the 46 eyes with macular detachment, good visual rehabilitation and a visual acuity improvement of 5 or more lines was obtained in 33 eyes (71.7%) by 1 month postoperatively. No statistically significant difference in the reattachment rate was found when eyes that underwent an encircling procedure were compared with those that did not. In eyes with lens opacity, cataract surgery was also performed and intraocular lenses were implanted uneventfully in all but one case with myopia. There was a high incidence (53.8%) of cataract progression in phakic eyes. However, no other serious complications, such as proliferative vitreoretinopathy, were found throughout the follow-up period.

CONCLUSIONS

The results indicate that vitrectomy performed to alleviate peripheral vitreoretinal traction is an effective surgical technique to treat primary rhegmatogenous retinal detachment. Vitrectomy combined with cataract surgery may also be a valuable surgical option in selected cases to maintain long-standing visual rehabilitation.

[A comparative study of visual outcomes following primary vitrectomy and scleral buckling procedures to manage macular off rhegmatogenous retinal detachments]

PURPOSE

To determine the difference between two types of retinal detachment surgery in postoperative visual recovery in the management of macular-off rhegmatogenous retinal detachment.

METHODS

We evaluated retrospectively the postoperative visual acuity (VA) in 37 patients who underwent primary vitrectomy (group V) and 39 patients treated with conventional scleral buckling (group S).

RESULTS

Although the mean preoperative VA in group V (0.03) was significantly worse (p = 0.04) than that in group S (0.06), there was no statistically significant difference between the groups in postoperative VA throughout the follow-up period. However, in the cases with poor preoperative VA (VA < 0.1), ocular hypotony (IOP < 7 mmHg), or prolonged macular detachment (duration > 7 days), the visual recovery was significantly better (p < 0.05) in group V than in group S from 1 month postoperatively. There were more eyes with a final VA of more than 0.5 in group V than in group S. When considering only the eyes with lenses spared intraoperatively, postoperative cataract progression resulting in secondary visual reduction was statistically significantly greater (p < 0.01) in group V (62%) than in group S (8%).

CONCLUSIONS

Primary vitrectomy is effective to attain early visual rehabilitation, especially to manage macula-off retinal detachments with poor preoperative VA, ocular hypotony, and prolonged macular detachment. To prevent a secondary visual reduction, cataract surgery combined with vitrectomy is recommended in selected cases.

Serotypes of human rotaviruses in 7 regions of Japan from 1984 to 1997

Human rotavirus (HRV) serotypes were studied from diarrheal stool specimens in children in 7 regions of Japan (Sapporo, Tokyo, Maizuru, Osaka, Kagawa, Kurume, and Saga) from 1984 to 1997 by enzyme immunoassay (EIA) with serotype-specific monoclonal antibodies against serotypes 1, 2, 3, and 4. In addition, reverse transcription-polymerase chain reaction (RT-PCR) was conducted for analysis of "others" which included nonserotypable and mixed-serotype rotavirus specimens by EIA. In 3756 rotavirus-positive specimens, serotype 1 was detected in 2649 (70.5%), serotype 2 in 362 (9.6%), serotype 3 in 232 (6.2%) and serotype 4 in 196 (5.2%). Overall, serotype 1 was predominant from 1984 to 1997, although there were a few cases in which serotype 2, 3 and 4 became predominant based on area and year. The frequency of serotype 1 has gradually increased since 1993. Twenty two, 2, 3 and 1 among 57 specimens of "others" by EIA from Tokyo, Maizuru, Sapporo and Kurume in 1995-1996 and 1996-1997 were determined as serotypes 1, 2, 3, and 9 by RT-PCR, respectively.

Quantitative assessment of macular thickness in normal subjects and patients with diabetic retinopathy by scanning retinal thickness analyser

AIMS

To evaluate the scanning retinal thickness analyser (RTA), a novel non-invasive imaging instrument, in diagnosing and quantitatively characterising diabetic macular oedema, and to investigate the relation between central macula thickness measured by RTA and other clinical examinations.

METHODS

Central macular thickness was measured using the RTA in 40 normal subjects and 60 patients with diabetic retinopathy. The reproducibility of the retinal thickness measurements was evaluated by calculating the mean of the inter- and intrasession variations. Central macular thickness was correlated with the results of visual acuity measurements, biomicroscopy, and fluorescein angiography.

RESULTS

Intra- and intersession reproducibility of the RTA in normal subjects was plus or minus 5.2% (16 microns) and plus or minus 6.1% (19 microns), respectively. The mean central macular thickness was 182 (SD 16) microns in normal subjects, 283 (116) microns in diabetic eyes without clinically significant macular oedema (CSMO), and 564 (168) microns in diabetic eyes with CSMO. Central macular thickness was significantly greater (p < 0.001) in eyes with diabetic retinopathy than in normal subjects, even when macular thickening did not meet the standard for CSMO (p = 0.019) measured by biomicroscopy. Although greater fluorescein leakage at the macula results in greater central macular thickness, only eyes with diffuse leakage had statistically significant macular thickening compared with normal subjects (p = 0.022). Central macular thickness measured with the RTA was significantly correlated with the logarithmic converted visual acuity (r2 = 0.76) in diabetic eyes.

CONCLUSION

Scanning RTA, which has good reproducibility, might be useful to quantitatively detect and monitor macular thickening in diabetic retinopathy. Central macular thickness was highly correlated with logarithmic converted visual acuity in diabetic macular oedema.

Long-term follow-up of primary anterior chamber intraocular lens implantation

PURPOSE

To evaluate the long-term outcome in eyes having primary anterior chamber intraocular lens (AC IOL) implantation.

SETTING

Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan.

METHODS

Primary AC IOL implantation was performed in 171 eyes from 1983 to 1988. Two lenses were implanted: the open C-loop Simcoe lens and the 4-point fixation Kelman lens. In 86 eyes that had a mean follow-up of 9 years 7 months, visual acuity, corneal endothelial cell density, pupil shape, and the presence of associated complications were examined.

RESULTS

Although the final visual acuity was 0.5 or better in 60 eyes (69%), corneal endothelial cell density was less than 2000 cells/mm2 in 46 eyes (57%). Postoperative complications included a deformed pupil in 48 eyes (56%) and bullous keratopathy in 12 eyes (14%). In 14 eyes the AC IOL was explanted; 11 of these were the open C-loop Simcoe lens.

CONCLUSION

Although our findings show that the open C-loop AC IOL (Simcoe) is contraindicated, implantation of the 4-point fixation AC IOL may be acceptable in selected cases.

Measuring the anterior capsule opening after cataract surgery to assess capsule shrinkage

PURPOSE

To measure anterior capsule opening (ACO) size after acrylic intraocular lens (IOL) implantation and study the natural course of ACO reduction.

SETTING

Kimura Eye and Internal Medicine Hospital, Hiroshima, Japan.

METHODS

This study comprised 32 patients (38 eyes) having continuous curvilinear capsulorhexis, phacoemulsification, acrylic IOL implantation, and a self-sealing incision performed by 1 surgeon. A retroillumination photograph of the ACO was obtained with the Anterior Eye Segment Analysis System and converted to a computer image. The images were used to measure ACO size postoperatively and calculate the reduction ratio. Follow-up was 6 months.

RESULTS

The postoperative reduction ratio in ACO size was 2.14% at 1 week, 3.83% at 1 month, 4.29% at 3 months, and 5.03% at 6 months. In a few cases, the reduction was progressively severe throughout the follow-up.

CONCLUSIONS

The anterior capsule opening shrank rapidly during the first month after acrylic IOL implantation, followed by a slower progressive reduction in the subsequent 6 months. When severe, progressive shrinkage occurs, an anterior neodymium:YAG laser capsulotomy should be performed within 2 months postoperatively.

[Long-term results after simple vitrectomy for age-related macular degeneration with vitreous hemorrhage]

We reviewed the cases of 10 eyes with vitreous hemorrhage secondary to submacular hemorrhage associated with age-related macular degeneration, in which vitrectomy was performed without subretinal management. Vitreous hemorrhage occurred within 3 weeks of submacular hemorrhage. After vitrectomy, residual subretinal hemorrhage was rapidly absorbed and choroidal neovascularization was undetectable. After the surgery visual acuity improved over that of submacular hemorrhage in 5 eyes. Mean follow-up was 25 months and final visual acuity was 0.2 or better in 6 eyes (60%). Final visual outcome was highly corelated with the period from subretinal hemorrhage to vitrectomy, the thickness of subfoveal hemorrhage at vitrectomy, position of choroidal neovascularization, and duration of subretinal hemorrhage. Simple virectomy might be effective to stabilize submacular changes and improve visual acuity.

[Surgical indications and results of primary pars plana vitrectomy for rhegmatogenous retinal detachments]

To evaluate the efficasy of primary vitrectomy for uncomplicated rhegmatogenous retinal detachment associated with posterior hyaloid separation, a series of 63 eyes were reviewed retrospectively. The criteria for vitrectomy included not only eyes with posterior retinal breaks but also those with multiple peripheral retinal breaks. The reattachment rate was 92.1% (58 eyes) after the initial surgery, and finally this increased to 100%. Of the 46 eyes with macular detachment, good visual rehabilitation, i.e., visual acuity improved by 5 or more lines, was obtained in 71.8% (33 eyes) one month postoperatively. There was no statistically significant difference in the reattachment rate whether an encircling procedure was also done or not. In eyes with lens opacity, cataract surgery was also done and intraocular lenses were implanted uneventfully in all but one myopic case. No serious complications such as proliferative vitreoretinopathy were found throughout the follow-up period except for the high incidence (53.8%) of cataractous progression. The results indicate that vitrectomy, removing the peripheral vitreo-retinal traction directly, is an effective procedure for primary rhegmatogenous retinal detachment. Vitrectomy combined with cataract surgery is also proposed as a valuable strategy in selected cases to maintain visual rehabilitation.

Sequence analysis of SRSV in fecal specimens from an epidemic of infantile gastroenteritis, October to December 1995, Japan

From October to December in 1995, an epidemic of infantile gastroenteritis occurred all over Japan except in Hokkaido and Okinawa prefectures. The number of infected infants and young children was estimated to be over 5 million cases [Editorial, IASR 1996]. The stool specimens from patients were examined for the presence of small round structured viruses (SRSVs) by reverse transcription-polymerase chain reaction (RT-PCR) and nucleotide sequencing of parts of the RNA-dependent RNA polymerase region. Thirty-five of 87 stool specimens examined gave positive results. Genomic variation was investigated by sequence analysis of a 327 bp cDNA region. The nucleotide and deduced amino acid sequences of the ten strains segregated into two distinct groups; one showed 96.0-100% nucleotide and 99.1-100% amino acid identity, the others showed 91.4-99.7% nucleotide and 93.5-100% identity. The main mechanism of transmission remains unknown. However, these data suggest the possibility of person-to-person spread by two or more kinds of SRSV.

Multifrequency laser emission generated by two-color stimulated Raman effect using a single-frequency laser beam and a dye-Raman composite resonator

A single-color circularly polarized laser beam is focused into pressurized hydrogen to generate rotational stimulated Raman emission. After being corrected to a linearly polarized beam, this two-color laser beam is passed through a dye amplifier and is focused into pressurized hydrogen, again to generate multifrequency laser emission by the two-color stimulated Raman effect. The laser beam is further confined in a resonator, which enhances intracavity intensity leading to increased efficiency. In these experiments, more than 11 rotational lines are generated simultaneously at 5 atm, and many additional vibrationally shifted rotational lines are generated at 9 atm.

Rheological evaluation of X-ray irradiated blood

CPD blood, in glass containers and polyvinyl chloride (PVC) bags, was X-irradiated with 50 Gy (n = 4), and then stored for up to 4 weeks. Rheological, hematological and biochemical changes of the red cells during storage were examined. Changes in blood viscosity and various properties of red cells (deformability, shape, hematological indices and concentrations of 2,3-diphosphoglycerate and nucleotides) during storage at 4 degrees C were not altered by the irradiation. The rheological, biochemical and morphological properties of red cells were as well preserved in PVC bags as in glass containers. No abnormal and/or cross-linked proteins in red-cell membranes were induced by the irradiation. Irradiation of PVC bags did not affect the above properties of red cells through any changes in the bag constituents. In conclusion, X-ray irradiation with 50 Gy to CPD blood in PVC bags does not affect the rheological functions of red cells.

Subtypes of herpes simplex virus type 1 in Japan: classification by restriction endonucleases and analysis of distribution

An attempt was made to classify herpes simplex virus type 1 (HSV-1) isolates into subtypes on the basis of the combination of the gain or loss of specific cleavage sites of HSV-1 genomes with each of three restriction endonucleases (Bam HI, Kpn I, and Sal I). According to the criteria we used for the determination of HSV-1 subtypes, 93 strains of HSV-1 that were isolated in three areas of Japan (Sapporo, Tottori, and Kagawa) were tentatively classified into eight subtypes: subtypes A-H. The bulk of the strains (84 of 93) fell into three subtypes: A, C, and H. There were highly significant differences (P less than .01) in the proportion of subtypes A and H that were isolated in Sapporo as compared with those isolated in Tottori and in Kagawa, which are geographically far from Sapporo. No significant differences, however, were found in subtypes isolated in Tottori as compared with those isolated in Kagawa, which are geographically close to each other. These data suggest that there might be a correlation between the genome structure of HSV-1 and the areas of their isolation in Japan.