Toshiaki Hayashi

Postoperative neurological deterioration in pediatric moyamoya disease: watershed shift and hyperperfusion

OBJECT Young patients with moyamoya disease frequently exhibit extensive cerebral infarction at the time of initial presentation, and even in the early postoperative period. To investigate clinical characteristics in the early postoperative period, the authors prospectively analyzed findings of MR imaging, MR angiography, and SPECT before and after surgery. The authors focused in particular on how postoperative neurological deterioration occurred. METHODS Between August 2005 and June 2009, 22 patients younger than 18 years of age with moyamoya disease were treated at Miyagi Childrens Hospital. The mean patient age (+/- SD) was 8.58 +/- 4.55 years (range 2-17 years). Superficial temporal artery-middle cerebral artery bypass and indirect bypass of encephalosynangiosis between the brain surface and the temporal muscle, galea, and dura mater were performed in 35 hemispheres. Magnetic resonance imaging and MR angiography were performed before surgery, at 7 days postoperatively, and 3-6 months after surgery. A (123)I-isopropyl iodoamphetamine SPECT scan was also obtained pre- and postoperatively. RESULTS During the postoperative period, neurological deterioration was observed after 15 operations (10 cases of motor paresis, 1 of aphasia, and 4 of sensory disturbance) in 13 patients. All symptoms had resolved by the time of discharge, except in 2 patients who suffered cerebral infarction. All patients exhibited disappearance (94.3%) or reduction (5.7%) of transient ischemic attacks (TIAs) during the follow-up period. Perioperative studies revealed 2 different types of radiological findings, focal uptake decrease on SPECT indicative of cerebral ischemia due to dynamic change in cerebral hemodynamics caused by bypass flow, the so-called watershed shift, and perioperative edematous lesions on MR imaging due to cerebral hyperperfusion. The frequent occurrence of preoperative TIAs was significantly associated with watershed shift, whereas preoperative MR imaging findings and preoperative SPECT findings were not. Age at operation was the only factor significantly associated with postoperative hyperperfusion. CONCLUSIONS In young patients, moyamoya disease exhibits rapid progression, resulting in poor clinical outcome. The risk of postoperative neurological deterioration in very young moyamoya patients with frequent TIAs should be noted. The findings in this study showed that direct bypass is not completely safe in patients with moyamoya disease because it causes dynamic change in postoperative cerebral hemodynamics.

Rhabdomyomatous mesenchymal hamartoma associated with nasofrontal meningocele and dermoid cyst.

A 1‐year‐6‐month‐old girl presented with a subcutaneous tumor of the forehead, which had developed since birth. The preoperative examinations showed nasofrontal bone defect with meningocele and subcutaneous tumor with cyst. The patient underwent excision of the tumor and reconstruction of the bone defect. Histologically, the skin tumor exhibited disordered arrangement of striated muscle fibers among normal dermal components, and the cyst was lined by cornified epithelium with a few hair adnexa and contained lamellated keratin. These findings were consistent with rhabdomyomatous mesenchymal hamartoma (RMH) and dermoid cyst. This is an interesting case of RMH co‐existing with nasofrontal meningocele and dermoid cyst in the same area. We suggest embryologic errors as a possible etiology, which is incomplete dysjunction of the neural ectoderm from the cutaneous ectoderm. Failure of insertion of mesoderm between the ectoderms caused the bone defect and the disordered proliferation and differentiation of mesoderm‐derived tissue, leading to formation of hamartoma.

Ameliorative effect of glial cell line-derived neurotrophic factor on brain edema formation after permanent middle cerebral artery occlusion in rats

Glial cell line-derived neurotrophic factor (GDNF) was applied topically on the brain surface immediately after permanent middle cerebral artery (MCA) occlusion in rats. In contrast to the cases treated with vehicle, a formation of brain edema was significantly reduced at one day by the treatment with GDNF. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) staining was markedly reduced in the cases with GDNF treatment at 12 h after MCA occlusion. However, the induction of immunoreactive 70-kd heat shock protein (HSP70) was slightly ameliorated by the GDNF treatment. The present results suggest that the treatment with GDNF has a significant effect on ameliorating brain edema formation after continuous brain ischemia, and the effect is greatly associated with the reduction of apoptotic changes, but slightly with that of stress response of cells.

Efficacy of intraoperative irrigation with saline for preventing shunt infection

OBJECT The rate of infection following shunt procedures is unacceptably high. The authors have hypothesized that the key to reducing the shunt infection rate is in reducing bacteria in the operating field and wound. This hypothesis has been tested in a prospective nonrandomized controlled manner. METHODS Data obtained in all patients undergoing shunt insertions or revisions for hydrocephalus performed between October 1, 2003, and June 12, 2009, were reviewed. Starting in August 2006, we began routinely irrigating the operating field and wound with saline solution from a syringe. Prior to this, we had not used any irrigation techniques, providing an adequate control group (Group A) for the effect of the irrigation technique. Prior to November 2007, we used saline containing amikacin for irrigation (Group B). After that date, we used saline only for irrigation (Group C). RESULTS A total of 150 shunt procedures were performed in 79 girls and 71 boys during the study period. The mean age of all patients was 44.0 +/- 59.1 months. Groups A, B, and C comprised 61, 40, and 49 shunt procedures, respectively. There was no statistical difference in age among the 3 groups. Nine infections occurred within 90 days in the postoperative period. The overall infection rate was 6.0%. Eight infections occurred before introducing the irrigation procedure (infection rate 13.1%). One infection was noted after introducing irrigation (Group B [0.0%] + Group C [2.0%]; combined B and C infection rate = 1.1%). There was a statistical difference in the infection rate between Group A and Groups B and C combined (p = 0.003), Groups A and B (p = 0.021), and Groups A and C (p = 0.035). In contrast, no statistical difference was observed between Groups B and C (p > 0.99). Six of the 9 infections were due to staphylococcal species. CONCLUSIONS An irrigation technique used to reduce bacteria in the operating field and wound is effective for preventing shunt infection. Irrigation alone, and not antibiotics, contributed to the prophylaxis of shunt infection.

Optochiasmal arachnoiditis following cotton wrapping of anterior communicating artery aneurysm treated by surgical removal of granuloma.

We report the case of a 50 year old female who presented with visual disturbance due to optochiasmal arachnoiditis and foreign body granuloma 9 months after cotton wrapping for ruptured anterior communicating artery (AcomA) aneurysm. Magnetic resonance imaging (MRI) revealed enhanced mass lesion around AcomA complex and hyperintense signal on optic chiasm and right optic tract by fluid-attenuated inversion recovery image. Despite the repeated steroid pulse therapy, she deteriorated and MRI showed expansion of the granulomatous lesion over 5 months. Surgical removal of foreign body granuloma resulted in marked improvement of visual disturbance as well as of the MRI findings. We conclude that the use of cotton sheet close to the optic nerve should be avoided, and that surgical removal of the granuloma would be the optimal choice especially for the patient in whom steroid therapy fails to improve clinical symptoms.

Shunt placement after cyst fenestration for middle cranial fossa arachnoid cysts in children

OBJECT Some pediatric patients with middle cranial fossa arachnoid cysts present with symptoms of increased intracranial pressure (ICP) and require shunt placement after a cyst fenestration. However, factors concerning increased ICP after fenestration followed by shunt placement have not been elucidated. This study evaluated factors that are associated with shunt placement following cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. METHODS Twenty-six pediatric patients with middle cranial fossa arachnoid cysts who were surgically treated at a single institution between 2004 and 2013 were retrospectively identified. The surgical indications for middle cranial fossa arachnoid cysts were as follows: 1) arachnoid cysts associated with symptoms such as headache and abnormally enlarging head circumference; 2) progressively expanding arachnoid cysts; and 3) large arachnoid cysts such as Galassi Type III. A cyst fenestration was performed as a first-line treatment, and shunt placement was required if symptoms associated with increased ICP were found following fenestration. The risk factors evaluated included age, sex, presenting symptoms, the presence of head enlargement, progressive cyst expansion, and subdural hematoma/hygroma. RESULTS Four patients (15.4%) required shunt placement after cyst fenestration. Younger age, abnormal head enlargement, and progressive cyst expansion before fenestration were significantly associated with the need for shunt placement following fenestration. Arachnoid cysts decreased in size in 22 patients (84.6%) after fenestration and/or shunt placement. The presence of symptoms was not associated with postoperative cyst size in this study. CONCLUSIONS In this study, younger age, abnormal head enlargement, and progressive cyst expansion were risk factors for shunt placement after cyst fenestration in pediatric patients with middle cranial fossa arachnoid cysts. It is important to consider that cyst fenestration may not be effective because of a latent derangement of CSF circulation in patients with these risk factors.

Post-operative changes of cerebral circulation and metabolism in the acute stage of low-grade aneurysmal subarachnoid hemorrhage

Abstract Objective: Pre- and post-operative cerebral circulation and metabolism were evaluated in patients with low-grade acute aneurysmal subarachnoid hemorrhage (SAH) who underwent early surgery to investigate the effects on brain dysfunction. Methods: Positron emission tomography (PET) was performed to measure the regional cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), oxygen extraction fraction (OEF) and cerebral blood volume in four patients (one male and three females, mean age: 60.3 years) with low-grade SAH within 30 hours of onset. Post-operative PET was performed on the seventh post-operative day. No patient suffered clinical deterioration during the study. Pre-operative PET scans demonstrated significant global reduction of CBF and CMRO2, compared to 16 normal control subjects, and no significant change in OEF. CBF and CMRO2 reduction post-operatively improved to the normal control values. Post-operative OEF was significantly increased compared to the normal control value. Conclusions: Patients with low-grade SAH have impairment of cerebral circulation and metabolism in the acute period, which improves after surgery. Early surgery for low-grade SAH, necessary to avoid rerupture of the aneurysm, did not worsen the impairment of cerebral circulation and metabolism. However, measures to protect the brain from perioperative damage are necessary to achieve the optimum outcome.

Surgical indication and outcome in patients with postoperative retethered cord syndrome

OBJECT After untethering of spinal dysraphism, some patients present with neurological deterioration, defined as retethered cord syndrome. It is known that surgical untethering is an option for improving the symptoms of retethered cord syndrome. Previous reports have shown that postoperative improvement in retethered cord syndrome was noted in the majority of patients presenting with pain, and in more patients with motor weakness than in those with urological symptoms. The authors speculate that subjective symptoms may be detected while symptoms are still reversible. In contrast, changes in urological function are less easy to diagnose, and delays in treatment may be complicated by advanced symptoms. In this study, patients with retethered cord syndrome were evaluated to investigate the benefits of performing routine urodynamic study to detect detrusor overactivity, which is considered to be a subclinical change of urological function, and to investigate the efficacy of early untethering surgery on the symptoms of retethered cord syndrome. METHODS Surgical indications and outcomes of 78 untethering operations (20 for myelomeningocele, 58 for spinal lipoma) for retethered cord syndrome were examined. Diagnosis of retethered cord syndrome was defined by a multidisciplinary spina bifida team, and included routine urodynamic study. RESULTS Preoperative symptoms included urological symptoms (70%), lower-extremity symptoms (45%), and others. The most frequent urological symptom was detrusor overactivity detected by urodynamic study (88.7%). Urinary incontinence was only found in 9.4% of patients. Postoperatively, progressive motor weakness improved in all patients, and sensory symptoms improved in 94%. Urological symptoms improved in 80% of the patients with urinary incontinence and in 75% of the patients with detrusor overactivity. Postoperative urodynamic study showed a significant increase in bladder volume (p < 0.05). The most common complication was temporary lower leg paresthesia that recovered at follow-up. Aggravated dysuria was noted in 3 patients. CONCLUSIONS Early untethering operations offer symptomatic relief to patients with retethered cord syndrome. Urodynamic study findings, especially detrusor overactivity, are considered to be the most significant indicators for early diagnosis of retethered cord syndrome.

Delayed Deterioration in Isolated Traumatic Subarachnoid Hemorrhage.

BACKGROUND Isolated traumatic subarachnoid hemorrhage (SAH) in association with mild traumatic brain injury is considered to be a less severe finding that is not likely to require surgical intervention. No previous reports have described cases warranting craniotomy for isolated traumatic SAH by itself. CASE DESCRIPTION We report 2 cases of minor head trauma with isolated traumatic SAH that showed delayed clinical deterioration requiring immediate surgical intervention. Initial computed tomography showed isolated traumatic SAH in the basal cistern and Sylvian fissure in both cases. Angiography showed no aneurysmal source. Within 24 hours of each accident, both disturbance of consciousness and hemiparesis deteriorated. Follow-up computed tomography showed formation of intracerebral hematoma adjacent to the Sylvian fissure. Intraoperative findings showed abruption injury of a perforating branch arising from the middle cerebral artery (MCA) as the cause of bleeding. Impact at the time of injury could have caused traction on the MCA in the Sylvian fissure, resulting in abruption of the perforator. CONCLUSIONS Isolated traumatic SAH seen in the basal cistern and Sylvian fissure carries a risk of late deterioration. A possible cause of hematoma expansion is abruption of a perforating branch arising from the MCA at the time of head injury. When hematoma expansion is identified, surgical evacuation of the hematoma is indicated. Surgical evacuation should be safely performed with the knowledge of the point of bleeding in such patients.

Acute Subdural Hematoma in Infants with Abusive Head Trauma: A Literature Review.

The number of cases with child abuse is increasing in Japan, and abusive head trauma (AHT) is a major cause of death in abused children. Child abuse has been recognized by the late 19th century, and widely accepted as battered child syndrome in the middle of the 20th century. As terms, there had been considerable mechanistic controversies between shaken-baby and -impact syndrome until the beginning of the 21st century. In recent years, AHT has been utilized as a less mechanistic term. Most of the characteristics of AHT in Japan have been similar to those in the United States as follows: infant is the most common victim, acute subdural hematoma (SDH) is the most common intracranial lesion, and retinal hemorrhage is often complicated. On the other hand, several characteristics have been different as follows: mother is the most common perpetrators, impact is a more common mechanism of trauma than shaking, and external trauma is more common reflecting the existence of impact. Since AHT as well as child abuse is a social pathological phenomenon influenced by victims, perpetrators, socioeconomic circumstances, and so on, various aspects of AHT as well as child abuse can be changed with times. Actually, a recent paper suggests such changes in infants with acute SDH due to AHT. In this review article, AHT, abusive infantile acute SDH in particular, are reviewed from the aspect of neurosurgical perspectives, including its mechanisms of trauma, biomechanics, clinical features, management, and prognosis, to update the trend in Japan.