Izumi Koyanagi

The role of radiotherapy in the management of spinal cord glioma

PURPOSEnTo determine the role of radiotherapy in the management of spinal cord gliomas.nnnMETHODS AND MATERIALSnThirty-six patients with spinal cord glioma treated between 1979 and 1993 were examined. The patients had 13 astrocytic tumors (7 astrocytomas, 4 anaplastic astrocytomas, 2 glioblastomas), 22 ependymal tumors (18 ependymomas, 4 myxopapillary ependymomas), and 1 unclassified glioma. Fifteen of the patients were treated by surgery alone, but the remaining 21 patients also received postoperative radiotherapy. Total resection was performed on 1 astrocytoma and 13 ependymomas. In general, 40-50 Gy/16-20 fractions/4-5 weeks were given after parital resection, but no radiotherapy was given after total resection.nnnRESULTSnActuarial survival was significantly better for patients with ependymal tumors than for those with astrocytic tumors (p = 0007), 5-year actuarial survival rates being 96% and 50% for patients with ependymal tumors and astrocytic tumors, respectively. For patients with ependymal tumors, there was no difference in motor function and survival between those with total resection and those with partial resection followed by radiotherapy. Actuarial 3-year survival was 80% for patients with astrocytomas and 40% for those with anaplastic astrocytomas plus glioblastomas. The difference in the degree of motor function between the patients treated with radiotherapy and those without radiotherapy was not statistically significant. One anaplastic astrocytoma and one glioblastoma patient have lived longer than 4 years after radical treatment including radiocordectomy, or irradiation using doses larger than the tolerance threshold of the spinal cord.nnnCONCLUSIONnPostoperative conventional radiotherapy is indicated after less than total resection of low-grade ependymal tumors and astrocytomas but not after total resection of ependymomas. Radiocordectomy may be an option for certain cases with high-grade astrocytic tumors.

Surgical treatment supposed natural history of the tethered cord with occult spinal dysraphism

Abstract We retrospectively evaluated the pre- and postoperative course of 34 tethered cord patients with occult spinal dysraphism in an attempt to infer the natural history of this disorder and to determine the effectiveness of the surgical treatment. There were 32 cases with lumbosacral lipoma and 2 with tight filum terminale. The age at surgery ranged from 1 month to 47 years old. Eight patients, aged 1 month to 4 years old, were asymptomatic; 26 had neurogenic bladder (26 cases) or motor problems affecting the legs (8 cases). None of the patients older than 5 years of age were asymptomatic. Untethering of the spinal cord was performed in all cases. The postoperative follow-up period ranged from 5 months to 11 years. During these periods, 7 (88%) of the 8 asymptomatic patients remained neurologically intact, 6 (23%) of the 26 symptomatic patients showed improved symptoms, and 15 patients (58%) remained unchanged. These results indicate that the neurological symptoms will appear progressively in the tethered cord patients, and that prophylactic surgery should be considered as early as possible.

Reevaluation of syringosubarachnoid shunt for syringomyelia with Chiari malformation.

OBJECTIVEnThe purpose of this study was to evaluate the effectiveness of syringosubarachnoid (S-S) shunting for syringomyelia with Chiari malformation. The authors describe the technical methods of performing the S-S shunt and the clinical results, including shunt malfunction.nnnMETHODSnForty-nine patients underwent S-S shunting. These patients were divided into three groups according to differences in the surgical technique used. Group I patients underwent laminectomy plus midline myelotomy and had a shunt tube placed in the dorsal subarachnoid space. Group II patients underwent laminectomy plus dorsal root entry zone myelotomy and had a shunt tube placed in the dorsolateral subarachnoid space. Group III patients underwent hemilaminectomy plus dorsal root entry zone myelotomy and had a shunt tube placed in the ventrolateral subarachnoid space.nnnRESULTSnClinical results were generally satisfactory, especially in terms of pain relief, in all three groups. However, 10 patients among Groups I and II required follow-up surgery because of shunt problems; no second surgery was necessary for any patient in Group III.nnnCONCLUSIONnThe S-S shunt was very effective in deflating the syrinx, and the clinical results were satisfactory. Therefore, even though foramen magnum decompression is a very effective treatment, S-S shunting should be reevaluated and not rejected; it should be considered as one of the major surgical options. To prevent the possibility of cord injury by myelotomy or shunt malfunction, the dorsal root entry zone should be selected as the myelotomy site, and the shunt tube should be inserted into the ventral subarachnoid space at the cervical level.

Spinal cord evoked potential monitoring after spinal cord stimulation during surgery of spinal cord tumors.

Spinal cord evoked potentials (SCEPs) after spinal cord stimulation were used as a method of spinal cord monitoring during surgery of 6 extramedullary and 14 intramedullary spinal cord tumors. SCEPs were recorded from an epidural electrode placed rostral to the level of the tumor. Electrical stimulation was applied on the dorsal spinal cord from a caudally placed epidural electrode. The wave forms of SCEPs consisted of a sharp negative peak (N1) in 15 cases and two negative peaks (N1 and N2) in 5 cases. The N2 wave was markedly attenuated by posterior midline myelotomy, whereas the N1 activity showed less-remarkable changes by myelotomy. An increase in N1 amplitude was observed after the removal of the tumor in four extramedullary and three intramedullary cases. Of six patients that showed decreased N1 amplitude after the removal of the tumor, five patients developed postoperative motor deficits. However, there were four false-negative cases and one false-positive case in regard to changes of N1 amplitude and postoperative motor deficits. Four false results occurred in intramedullary cases. In two of them, postoperative symptoms indicated intraoperative unilateral damage to the spinal cord. The position of the stimulating electrode, the difference in thresholds of the axons for electrical stimulation between the right and left side of the spinal cord, or the change of the distance between the electrode and the spinal cord surface may account for these false results. Thus, our analysis of the changes of SCEP wave forms and early postoperative symptoms indicates that the sensitivity of this monitoring method to detect intraoperative insults to the spinal cord is unsatisfactory in spite of the reproducible wave forms. We conclude that SCEP monitoring can be used as an alternative method or in combination with other types of evoked potentials in patients with severe spinal cord lesions who show abnormal somatosensory evoked potentials preoperatively.

Surgical treatment of syringomyelia associated with spinal dysraphism

Abstract Clinical and radiological features of syringomyelia in 15 patients with spinal dysraphism are reported. There were 8 patients with occult spinal dysraphism (lumbosacral lipoma) and 7 with spina bifida aperta (meningomyelocele). Syringomyelia with spinal dysraphism can be radiologically divided into two types according to the dysraphic state. The syrinx in the patients with occult spinal dysraphism occurred immediately rostral to the lipoma and was localized to the lower thoracic to lumbar levels, while in the meningomyelocele patients the syrinx extended from the cervical to the thoracic level. Large syrinx formation was recognized in 1 of the 7 occult spinal dysraphism cases and 3 of the 8 meningomyelocele cases. For syringomyelia with occult spinal dysraphism, 4 patients underwent syringo-subarachnoid shunting (S-S shunt, 2 cases) or syringostomy (2 cases) during an untethering operation. In the case of meningomyelocele, S-S shunts were placed in 2 patients. Collapse of the syrinx was achieved in all 6 patients who underwent S-S shunting or syringostomy. Decreased size of the syrinx was also noted in 3 occult spinal dysraphism patients who underwent untethering operations alone. In conclusion, a large syrinx in the case of spinal dysraphism should be surgically treated. S-S shunting is effective in both types of syringomyelia. Foramen magnum decompression may be an alternative method of surgical treatment for syringomyelia in patients with meningomyelocele.

Spontaneous Shrinkage of Lumbosacral Lipoma in Conjunction with a General Decrease in Body Fat: Case Report

OBJECTIVE AND IMPORTANCEnWe describe a rare case of a lumbosacral lipoma that shrank spontaneously in parallel to a general loss of body fat. Although early prophylactic surgery is generally recommended for lumbosacral lipomas, the observation made in this case may provide an important implication regarding the conservative management of this disorder.nnnCLINICAL PRESENTATIONnA 9-year-old male patient with a subcutaneous lipoma at the sacral level was found to have a lumbosacral lipoma in the spinal canal and tethered spinal cord, as revealed by magnetic resonance imaging. The patient showed no neurological or urological deficits, except for a mild pes cavus deformity.nnnINTERVENTIONnFollow-up magnetic resonance imaging performed 4 years later revealed a significant decrease in the size of the lumbosacral lipoma. The patient became very thin and showed no neurological deterioration during the follow-up period. The shrinkage of the lipoma was considered to be in association with the general loss of body fat.nnnCONCLUSIONnThe control of body weight may be an important factor in the conservative management of patients with lumbosacral spinal lipomas.

Syringo-subarachnoid shunt for syringomyelia using partial hemilaminectomy

Syringo-subarachnoid shunt (S-S shunt) is one of the established surgical procedures for syringomyelia. However, this procedure requires a laminectomy which may lead to spinal column complications. We present a modified form of S-S shunt using a partial hemilaminectomy; a S-S shunt is placed via the dorsal root entry zone into the anterior subarachnoid space which is considered to be an ideal site for the drainage of the syrinx fluid. This technique will decrease the incidence of neuronal and spinal complications after surgery and avoid subarachnoid adhesions around the shunt tube. Between 1992 and 1997, a total of 24 patients with syringomyelia have been treated with this surgical procedure without any complications. Collapse of the syrinx was achieved in all cases. The authors believe that the procedure is an effective surgical treatment for syringomyelia and can be applied safely to adolescent and child cases.

Significance of spinal cord swelling in the prognosis of acute cervical spinal cord injury

Seven cases of acute cervical cord injury examined by CT-myelography are reported. Cord swelling was observed in 2 patients who developed complete lesions. Another 5 cases had an incomplete lesions. Spinal cord swelling indicated severe cord damage. External decompression seemed to have little effect on cord swelling. When cord swelling is absent, neurological improvement was expected though the initial neurological state showed severe deficits. A further 4 patients who had an acute cervical cord injury who were treated by myelotomy at the injury site are also reported. Two patients obtained significant improvement in upper limb function. The presence or absence of cord swelling as shown by CT-myelography is important for diagnosing the severity of cord damage. Myelotomy in the immediate post-accident period may relieve the effects of cord swelling.

A split cord malformation

Abstract This report describes a case of split cord malformation without a septum. A 2-year-old boy presented with a 3-month history of neurogenic bladder. MRI did not show any apparent abnormality around the conus medullaris. However, CT myelography clearly demonstrated the presence of a split filum terminale. The patient underwent laminectomy of L1–5 laminas and untethering of the split filum terminale. CT myelography was superior to MRI in diagnosing split cord malformation in this case. As MRI is currently regarded as the superior imaging modality, this reported case may have been missed because the pathology was not apparent on MRI.