The role of spinal tissue scarring in the pathogenesis of progressive post-traumatic myelomalacia.

OBJECTIVES: Experimental spinal cord injury (SCI) with focal spinal tissue scarring was studied to better understand the progressive post-traumatic myelomalacia (PPM). METHODS: Using a stereotactic device, the authors developed an acute compression of spinal cord at Th-10 in the adult rat. In Group A, the rat thoracic spinal cord was compressed epidurally with preservation of local cerebrospinal fluid (CSF) dynamics. In Group B (spinal tissue scarring), the rat thoracic spinal cord was compressed directly after disruption of meninges of dura mater and arachnoid membrane, followed by gelatine sponge sealing. All rats were maintained for 12 weeks after injury. RESULTS: Imaging analysis revealed the significant increase of cystic cavitation in the contused spinal cord in Group B compared with Group A. Anterograde axonal tracing demonstrated that the labeled corticospinal axons had extended axonal sprouting into the nearby gray matter and displayed prominent dieback at the rostral interface of the spinal cord lesion in both groups. No significant difference in motor and sensory functions between the two groups was noted. DISCUSSION: The new experimental model of PPM formation was devised. Spinal tissue scarring at the injury site may cause a tethering effect on the spinal cord, which may lead to significant alteration of the spinal cord parenchyma. Although the devastating effect of PPM on motor and sensory functions is still not resolved completely, the results in the present study suggest the importance of careful analysis in the treatment of PPM after SCI.

A brainstem cavernoma demonstrating a dramatic, spontaneous decrease in size during follow-up: case report and review of the literature.

BACKGROUND: Many reports have demonstrated a worse prognosis for patients whose cavernomas were subtotally removed than for those whose cavernomas were not surgically treated. Therefore, it is better not to touch the cavernoma if a surgeon is not prepared to totally remove it. This report describes a large brainstem cavernoma showing a spontaneous, dramatic reduction in size after removal of only the biopsy specimen of the lesion. CASE DESCRIPTION: A 42-year-old woman experienced facial numbness, diplopia, and ataxia. A magnetic resonance (MR) study revealed a pontine cavernoma with hemorrhage. Two weeks later, recurrence of the patient's symptoms and consciousness disturbance were noted. An MR study revealed massive hemorrhage from the cavernoma with a ventricle dilatation. An operation on the lesion was conducted 3 months after the initial hemorrhage. However, the operation was aborted when an exploration of the lesion showed a tight adhesion between the lesion and the pons. Removal of only a biopsy specimen and evacuation of the suckable hematoma were done. No neurologic recovery and no decrease in the size of the cavernoma were detected postoperatively. Her family did not wish for further treatments. She was in a bedridden state with severe brainstem dysfunction when she was transferred to a local hospital. Sixteen months after the surgery, her consciousness was clear, and MR imaging confirmed a marked reduction in the size of the cavernoma. CONCLUSION: A dramatic, spontaneous decrease in size does occur even in the case of a large brainstem cavernoma showing hemorrhages. Conservative therapy may be one of the treatment options for the symptomatic brainstem cavernoma.

Adjuvant gamma knife radiosurgery after meningioma resection.

We evaluated the usefulness of adjuvant treatment with gamma knife radiosurgery following meningioma surgery. During the past 8 years, we operated on 78 patients with meningiomas. Among these, 28 patients (36%) received gamma knife radiosurgery postoperatively. The indications for radiosurgery were as follows: residual tumour after surgery in 13 patients (46.4%), regrowth of residual tumour during the follow-up period in 7 patients (25%), recurrence after total removal (Simpson grade 1 or 2) in 7 patients (25%), and another intracranial meningioma in one patient (3.6%). The tumour diameter at the time of radiosurgery ranged from 5.2 to 48.1 mm (median 21.6 mm). Larger tumours with a mean diameter above 40 mm in two patients were treated with two-staged radiosurgery. The tumor marginal dose ranged from 8 to 23 Gy (median 12 Gy). The follow-up period was 3-84 months (median 30 months) after radiosurgery. The tumour size decreased in 17 patients (60.7%), remained unchanged in 9 patients (32.1%), and increased in 2 patients (7.2%). No radiation injury was experienced. Adjuvant therapy using gamma knife radiosurgery for meningiomas can achieve control of tumour growth and may improve patient outcomes. Careful surgical planning and follow-up are required to understand the usefulness and limitations of radiosurgery in this setting.

Regrowth and fatal rerupture despite proximal occlusion after coil embolization of a ruptured large basilar bifurcation aneurysm--case report.

A 40-year-old man suffered chronic progressive symptoms of brainstem compression after undergoing endosaccular coil placement in a ruptured large basilar bifurcation aneurysm. Radiographical examinations showed coil compaction and regrowth of the aneurysmal mass with perifocal mesencephalic edema. The symptoms did not resolve even after additional clip occlusion of the upper basilar artery and the patient died of rerupture. At present, direct surgical clipping using a skull base technique with or without hypothermic circulatory arrest or upper basilar artery occlusion with or without bypass surgery may be a better choice as an initial treatment for giant or large basilar bifurcation aneurysm with a wide neck.

[The treatment for asymptomatic meningiomas in the era of radiosurgery].

We evaluated the treatment results in asymptomatic meningiomas in the era of radiosurgery. We encountered 56 patients with asymptomatic meningiomas from January, 1994 to December, 2001. There were 16 male patients and 40 female patients. The most common location was the cerebral convexity. We performed gamma knife radiosurgery for three patients after diagnosis of cavernous sinus meningiomas. The other patients were followed-up after diagnosis for a mean follow-up period of 30.8 months (5 months to 8 years). Tumor growth was verified in 25 patients (43%) and two patients (3.7%) suffered neurological deficits. Among the tumor growth patients, operative resection was performed in six patients (11%) and gamma knife radiosurgery was performed in four patients (7.5%). The other patients were placed under observation. We decided the treatment strategy paying attention to the tumor location, tumor growth speed, tumor size and operative difficulty. The tumor growth rate was 0.1 cm/year among the patients with tumor growth. It was 0.72 cm/year (0.02 to 1.54 cm/year) in the operative group, 0.3 cm/year (0.04 to 0.76 cm/year) in the gamma knife radiosurgery group and 0.08 cm/year (0.01 to 0.76 cm/year) in the observed group. One patient suffered procedure-related deterioration of paresis after operation. The treatment of asymptomatic meningiomas must be decided depending on their natural history and locations. We recommend early radiosurgery for cavernous sinus meningiomas.

[The surgical treatment strategy and results of parasellar meningiomas in the era of radiosurgery].

We evaluated the surgical treatment results of parasellar meningiomas in the era of radiosurgery. We treated 24 patients of parasellar meningiomas surgically. The median age was 60 yrs (ranging from 29 to 82 yrs). The most common tumor location was the sphenoid ridge in 12 patients and the tuberculum sellae in 7 patients. The pterional approach using fronto-temporal craniotomy was performed for all patients. The residual or recurrent tumors were treated by gamma knife radiosurgery (GKS). We are able to follow up these cases for a median of 3.8 yrs (ranging from 1 to 8 yrs) after the operations. The radicality of tumor resection was Simpson grade II in 13 patients (54%), grade III in 3 patients (13%) and grade IV in 7 patients (33%). Clinical improvement was achieved in 81% of the patients. Of the patients who had visual disturbance preoperatively, 8 patients (73%) showed improvement, but 3 patients suffered deterioration postoperatively. None of the patients died. One patient suffered transient memory disturbance and one patient suffered mild facial numbness postoperatively. Boost radiosurgery for the residual tumors was performed for six patients and tumor growth control was able to be achieved in all patients, with a median of 3.1 years follow-up period (ranging from 0.5 to 6 yrs). Five patients with tumor regrowth or recurrence were treated by GKS. We recommend fronto-temporal craniotomy with nonradical resection for parasellar meningiomas and radiosurgery for residual and recurrent tumors. This strategy will achieve good functional outcome with long-term tumor growth control.

[Results of treatment for male prolactinomas].

We evaluated the results of medical treatment for male prolactinomas. We encountered eight patients with male prolactinomas. The age was 25 to 54 years old (mean 43 years) and the chief clinical symptoms were visual acuity/field defect in three patients, pituitary apoplexy in one patient, disturbance of ejection in one patient, generalized convulsion in one patient, headache in one patient and general fatigue in one patient. The serum prolactin level was 279 to 7,360 ng/ml (mean 2,832 ng/ml). The tumors in all patients were large with a mean diameter of 34.9 mm (range, 21 to 43 mm). In only one patient, the operation was performed due to pituitary apoplexy. All the patients were treated by medication, with bromocriptine being used in seven patients and terguride in one. The follow-up period was 0.8 to 13 years (mean 5.9 years) and, in all patients, the medical treatment was continued. The tumor decreased in size in all patients and the serum prolactin level at the last follow-up observation was 0.5 to 70.5 ng/ml (mean 26.9 ng/ml). All the neurological symptoms disappeared in the early stage of treatment. As for the complications of medical treatment; in one patient, orthostatic hypotension occurred during the initial administration of bromocriptine and one patient suffered CSF leakage two months after the administration of bromocriptine, so the repair of the sella floor by transsphenoidal surgery was necessary. The medical treatment for male prolactinomas is effective for a long term and should be the primary treatment for the male prolactinomas. In conclusion, patients can maintain a good quality of life for a long time by using dopamine agonists.