Hans-Dietrich Herrmann

Hypothalamic Hamartomas: With Special Reference to Gelastic Epilepsy and Surgery

This study presents six patients with hypothalamic hamartomas diagnosed on the basis of magnetic resonance imaging. Histological confirmation was performed in three patients who underwent surgery. Immunohistological assays were used to determine the neurosecretory pattern. Four patients presented with epilepsy, including gelastic seizures. Other symptoms included behavioral abnormalities in four patients and precocious puberty and visual impairment in two patients. One patient presented associated developmental defects. Good results without morbidity were achieved with surgical resectioning in two patients with large hamartomas associated with behavioral abnormalities and gelastic epilepsy that was unresponsive to conventional medical treatment and in one patient with visual impairment. We propose a classification of the hypothalamic hamartomas based on topographical and clinical data obtained from 36 selected cases in the literature and six of our own cases. This classification should help to classify the various treatment methods and the surgical risks into four subgroups (Types la, lb, lla, and llb). We conclude that the surgical approach is a realistic alternative in certain cases, including large and broad-based Type llb hamartomas associated with gelastic epilepsy and behavioral disorders.

Growth factor biology and oncogene activation in human gliomas and their implications for specific therapeutic concepts.

&NA; The failure of most available treatment modalities to improve the survival time and the quality of survival in patients with gliomas calls for the intense biological analysis of glial neoplasia. The untimely activation of cellular proto‐oncogenes is often related to the process of neoplasia. Several protein growth factors as well as their cellular receptors have been identified as products of proto‐oncogenes. Furthermore, these growth factors have been identified as glial mitogens in normal glial cell cultures as well as in tumors. The analysis of growth factor biology gains additional weight by the demonstration of autocrine growth factor secretion by tumor cells. The role of epidermal growth factor (EGF) and its receptor system in glial cell proliferation and differentiation is presented, with the speculation that the EGF receptor system may integrate the biological actions of many different factors, of which EGF itself may be least important. The literature on platelet‐derived growth factor and insulin‐like growth factors is reviewed, and the biology of fibroblast growth factor is presented in perspective with such phenomena as neovascularization and cell‐matrix interactions. (Neurosurgery 25:681‐694, 1989)

Treatment of Nongerminomatous Germ-Cell Tumors of the Pineal Region

Germ-cell tumors can be subdivided into germinoma, embryonal carcinoma, choriocarcinoma, endodermal sinus tumor (yolk-sac tumor), and teratoma. They are also distinguished by their production of secreted markers such as alpha-fetoprotein produced in endodermal sinus tumors and embryonal carcinoma or beta-human chorionic gonadotropin, produced by choriocarcinoma and embryonal carcinoma. Germinoma and teratoma produce none of the markers. Because it has been proposed that teratomas may differentiate from multipotent stem cells contained in embryonal carcinoma and are thus lineage related, the presence of markers indicates the presence of a nongerminomatous germ-cell tumor. Nongerminomatous germ-cell tumors are an invariably fatal subgroup within the pediatric pineal region germ-cell tumors. There is no effective, established therapeutic regimen. We report the treatment regimen for three children diagnosed with this highly aggressive tumor entity. The children were first given a course of chemotherapy with bleomycin, etoposide, and cisplatin. This resulted in the normalization of markers and the shrinkage of tumors. These were then removed by the infratentorial supracerebellar approach. Removal was followed by a second course of chemotherapy with vinblastine, ifosfamide, and cisplatin; after which the children underwent radiotherapy. All three children are well and without evidence of residual or recurrent disease 20, 30, and 32 months after surgery, respectively. We propose this therapy regimen for children in whom the markers are positive.

Central neurocytoma: Clinical, immunohistologic, and biologic findings of a human neuroglial progenitor tumor

BACKGROUND Central neurocytomas are rare brain tumors recognized by their typical radiologic and histologic features. In general, a good prognosis is achieved by total removal. The histogenesis is still under debate, but a neuronal origin is widely assumed. METHODS This study presents the clinical and immunohistologic findings of five patients and the results of cell culture experiments of two patients with central neurocytoma treated surgically between 1983 and 1993. RESULTS The patient age at diagnosis ranged from 21 to 30 years (mean, 25 years). The male-to-female ration was 1:4. Raised intracranial pressure due to hydrocephalus was the main cause of the clinical manifestations. Total resection was achieved in two cases. Four patients received radiotherapy. One patient suffered a recurrence 1 year after surgery, requiring a second resection and radiotherapy. Follow-up studies took place between 1 and 10.5 years (mean, 7.1 years). To date, all patients are free of their tumors. Two patients suffered from permanent memory disturbances after surgery. Immunohistochemistry confirmed the neuronal nature of the tumors. Cell-culture studies, which have been carried out for the first time, demonstrated concomitant expression of neuronal (synaptophysin) and glial (GFAP) markers. CONCLUSION Total removal is the therapy of choice. In tumor recurrence or limited surgery (e.g. due to severe affliction of the fornical structures), radiotherapy has shown to be efficacious. The cell-culture experiments give new insight on the histogenesis of central neurocytoma, indicating that the tumor arises from an undifferentiated precursor cell with the capacity of bipotential neuroglial differentiation.

Intramedullary spinal cord tumors resected with CO2 laser microsurgical technique: recent experience in fifteen patients.

We have operated upon 15 intramedullary spinal cord tumors with the aid of a CO2 laser attached to the microscope. The operative technique is described. Most of the tumors were localized within the cervical spinal cord. Nine tumors were benign gliomas: 4 ependymomas, 1 subependymoma, 3 astrocytomas, and 1 ganglioglioma. Six were removed totally, and 3 were removed subtotally. The remaining 6 tumors consisted of 3 hemangioblastomas, 1 intramedullary neurofibroma, 1 lipoma, and 1 primary intramedullary melanoma. Neurological function postoperatively compared to the preoperative function of the upper extremities was unchanged in 13 patients (86.5%), improved in 1, and worse in 1 patient. In the lower extremities, the preoperative neurological status was unchanged in 11 patients (73.3%), improved in 1 patient, and worse in 3 patients (20%). Magnetic resonance imaging was superior to myelography and computed tomography in localizing these lesions. Enhancement with paramagnetic substances (e.g., gadolinium-DTPA) helps to localize solid tumor within cysts. Histological evaluation of small tissue biopsies or frozen section histology is unreliable. The entire lesion should be exposed in all cases, and an attempt should be made to remove the tumor totally or, if this is not possible, to resect as much of the center of the tumor as is possible until the cord is decompressed. The decision to administer further treatment is based on the histological features of the tumor.

Suprasellar meningiomas--neurological and visual outcome at long-term follow-up in a homogeneous series of patients treated microsurgically.

Summary Most of the previously published surgical series of suprasellar meningiomas have two disadvantages: (1) patients involved were treated within a relatively long time period, making analysis more difficult, (2) radiographic long term follow-up examinations with either CT- or MRI-scans were not performed. Both disadvantages were overcome in our retrospective clinical study, consisting of 50 consecutive patients with suprasellar meningiomas treated between 1982 and 1991. Radiological, ophthalmological, and neurological investigations were performed pre-operatively, postoperatively and at long term follow-up (mean: 5.7 years). A radiologically confirmed radical tumour removal could be achieved in 84% of patients. Both, the peri-operative mortality (2%) and serious operative morbidity (6%) were low. However, 12% of patients developed late onset epilepsy. At long term follow-up, visual function was improved in 67%, unchanged in 9% and worsened in 24%. In more than 50% of patients the vision showed recovery over a longer time period than the first 10 days after operation. Radiographic control examinations revealed tumour recurrences in 2 patients (both asymptomatic) and progress of residual tumour in 5 patients (2 symptomatic, 3 asymptomatic). Since introduction of modern neurosurgery, a clear improvement in the surgical treatment of suprasellar meningiomas can be observed. However, the still long delay in diagnosing these tumours correctly prevents a further improvement of the ophthalmological results at long-term follow-up. Due to a relatively high rate of late onset epilepsy, anticonvulsive prophylaxis for 6 months seems to be justified. Regarding present pre-operative diagnostic measures, ia-DSA seems only be indicated in patients with CT/MRI-scans, suspicious for tumourous narrowing or invasion of major cerebral arteries. In addition, we recommend radiographic control examinations at regular time intervals to confirm radical tumour removal and to detect the “ideal” point of time for renewed treatment.

Treatment of tumours of the pineal region and posterior part of the third ventricle

SummaryThe evaluation of tumours located in the posterior part of the third ventricle or pineal region is achieved best by magnet resonance imaging (MRI). It shows the exact localization and extent, the involvement of neighbouring structures like thalamus or quadrigeminal plate and the displacement of the large veins, the internal cerebral veins, the vein of Galen and the veins of Rosenthal. If only CT is available, angiography shoud be performed prior to operation to identify the course of the veins.In children with a pineal region tumour the “tumour markers” AFP and β-HCG should be determined before operation.We approach the rare tumours entirely located within the posterior part of the third ventricle by the posterior interhemispheric transcallosal route with the patient in prone position with the head elevated.The same approach is used for pineal region tumours extending above the internal cerebral veins.Tumours arising from the posterior thalamus extending into the thalamus and ventricle as well, are better approached by the posterior transcortical transventricular route since the lateral view is rather limited by the midline approach. The most frequent tumours in the pineal region are approached if they are located below the internal veins by the infratentorial, supracerebellar route in the sitting position.A total of 60 cases are evaluted.If AFP and/or β-HCG are positive a highly malignant nongerminomatous germ-cell tumour must be suspected. We recommend initial chemotherapy with a combination of Vinblastine, Ifosfamide and Cis-platin without biopsy to avoid tumour seeding. After the “markers” are normalized operative removal of the residual tumour and radiotherapy should be carried out.In a series of 13 children operated on for pineal region tumours a rigid neuropsychological and endocrine evaluation was perfomed with encouraging results. During the last 10 years we have performed 49 open operations and 11 stereotactic biopsies. 40% of the patients were children under the age of 18. 40% of the tumours in childhood and 60% in adults were benign. In childhood 24% were germinomas and 20% non-germinomatous germ cell tumours.The indications for stereotactic biopsy and for open operation after biobsy are discussed.

A joint protocol for the neurosurgical and neuroradiologic treatment of cerebral arteriovenous malformations: Indications, technique, and results in 76 cases

We report on a group of 76 patients who had been treated during a period in which preoperative embolization using interventional neuroradiologic technique was standard procedure. During this time, 20 consecutive patients were operated on without embolization, eight patients were treated with embolization only, and 48 patients were operated on after embolization. In 35 cases surgery immediately followed the last embolization procedure. All arteriovenous malformations (AVMs) were classified and the outcome analyzed according to Spetzler [J Neurosurg 1986; 65: 476-83]. Those lesions treated with a combination of embolization and surgery had higher Spetzler grading than those that had been operated without previous embolization. The overall recovery rate was 82.9%. In 7.9% of the cases the AVMs were not totally extirpated. The overall complication rate was 9.2%. It is concluded that preoperative embolization facilitates surgery and reduces the risk of severe morbidity and mortality, especially in high-grade lesions. In addition to the clinical results, the application and usefulness of Ethibloc as an embolizing agent is reported.

Bilateral microsurgical lysis of the spinal accessory nerve roots for treatment of spasmodic torticollis: follow up of 33 cases

SummaryIn 1981 we reported about a new surgical procedure for the treatment of spasmodic torticollis (ST). 33 patients, who failed to respond to the available conservative treatment, underwent a bilateral microsurgical lysis (BML) of the spinal accessory nerve roots (SRAN). Anastomoses between SRAN and the dorsal roots of the first and second cervical nerve (DRC 1/DRC 2) were cut. DRC 1 and sometimes DRC 2 were divided bilaterally. Moreover, SRAN was freed of all adhesions and vascular contacts.Up to 60 months after surgery we have exellent results in 5(5), good results in 10(7) and improved symptoms in 12(8) patients. In 3(7) patients symptoms were unchanged, 2(1) patients deteriorated (patients self assessment is given in brackets). One patient died during hospitalisation.Comparing torticollis symptoms and the post-operative outcome it can be shown that patients with horizontal ST have the best results (21 out of 22). Bad results were obtained in patients with combined torticollis symptoms such as retrocollis, antecollis and the rotatory/ horizontal type (5 out of 9).These results support the hypothesis of a peripheral factor in the aetiology of horizontal ST. It is assumed that a unilateral disturbance of proprioceptive afferents for head control, which reach the CNS via anastomosis between DRC 1/DRC 2 and SRAN (in 94% of the cases) could be involved. This hypothesis is discussed with special regard to different anatomical findings in patients with ST and those revealed in a study on human cadavers without this disease.

Treatment of neurogenic torticollis by microvascular lysis of the accessory nerve roots — indication, technique, and first results

SummaryFor treatment of spasmodic torticollis (s.T.) microsurgical decompression of the intraspinal-intracranial portion of the accessory nerve (a.N.) has been performed in 11 patients with proved neurogenic lesions of the accessory nerve-dependent muscles. Neurogenic lesions were discovered by meticulous electromyographic (EMG) examination in 26 out of 32 patients with s.T. Based on the EMG findings the a.N. roots were exposed, mostly bilaterally. During operation we found in each case tight adhesions to adjacent structures, in particular the vertebral artery (v.A.), the posterior inferior cerebellar artery (PICA), and spinal arteries. Moreover, various nerve anastomoses were found between the upper dorsal cervical roots and the spinal a.N. roots. After neurovascular lysis and dissection of anastomoses, to C 1 in particular, the a.N. was protected with teflon-foam (Prosthex). Immediately after surgery torticollis had improved in all but one case. Further improvement was achieved by exercises. These first favourable results, and the fact that nerve decompression is less destructive than other surgical procedures in treatment of s.T., make us feel justified in recommending this procedure further to patients suffering from s.T. with proved neurogenic lesions.