Stereotactic surgery in the management of deep intracranial lesions in infants and adolescents

Safe First-Time use of Stereotactic Headband Fixation in a 5-Month-Old Child: An Economical and Easily Accessible Method

OBJECTIVE

We present a low-cost and easily accessible adaptation system to perform stereotactic procedures in infants.

METHODS

We used an adaptive device consisting of a headband with a plaster bandage, cotton bandage roll, and gauze bandages. Prior to its clinical application, the device was tested in our neuroscience laboratory using a simulation model of a size similar to that of a 5-month-old infant, during which no complications arose. The headband cast technique was subsequently reproduced in a 5-month-old patient, serving as a fixation point for the placement of a Micromar frame for biopsy of a thalamic lesion.

RESULTS

A stereotactic biopsy was successfully performed in a 5-month-old patient using a headband cast to secure the stereotactic frame. This method enabled precise targeting of the selected site, resulting in a histopathological diagnosis without any associated complications.

CONCLUSIONS

The adaptive device is safe, easily accessible, and reproducible, facilitating the performance of stereotactic diagnostic procedures in infants, accurately reaching the planned objective without causing injuries or additional complications.

Frame-based stereotactic neurosurgery in children under the age of seven: Freiburg University's experience from 99 consecutive cases

INTRODUCTION

Stereotactic frame-based procedures proved to be precise, safe and are of widespread use among adult patients. Regarding pediatric patients few data is available, therefore the use of the stereotactic frame remains controversial in this population. This motivated us to report our experience in stereotactic procedures in the youngest patients and review the literature concerning this subject.

METHODS

All frame-based procedures performed in patients younger than seven years in the University of Freiburg during the last 10 years were retrospectively analyzed and discussed under the light of the current literature.

RESULTS

The studied population was composed of 72 patients under the age of seven (mean 3.4±2.1 years-old), in whom 99 stereotactic procedures were performed. Brain tumor was present in 60 patients, hydrocephalus in five, cystic lesions in three, intracranial abscess in three and epilepsy in one patient. Stereotactic surgery was performed in 36 cases for brachytherapy, in 29 for biopsy, in 20 cases for cyst puncture, in eight for stereotactically guided endoscopic ventriculostomy, in five for catheter placement and in one case for depth electrode insertion. The overall complication rate was 5%. There were three cases of pin penetration through the skull, one case of frame dislocation after extensive cyst drainage and two skull fractures. Neurologic deficit related to frame fixation was observed in none of the cases. In disagreement with other authors, no case of pin related infection, air embolism, hematoma or CSF leak was observed.

CONCLUSION

Frame-based stereotactic neurosurgery is a safe technique also in the youngest patients. Rather than the simple use of torque-limiting devices training and experience in the manual adjustment of the stereotactic frame in children have been proven to be crucial factors that contribute to reducing pin related complications.

The efficacy of a biopsy of intrinsic brainstem lesions for decision making of the treatments

OBJECT

The diagnosis of diffuse intrinsic pontine gliomas (DIPGs) has been generally made mainly by magnetic resonance imaging (MRI) and clinical course. However, the accuracy of MRI-based diagnosis has not been fully confirmed yet. Our aim was to review efficacy of biopsy for decision making of the treatments.

METHODS

We retrospectively analyzed pediatric patients undergoing biopsy for intrinsic brainstem lesions which were considered atypical for DIPGs by MRI findings. The lesion was evaluated atypical when it extended beyond the pons or it had a well-margined localized enhancing portion.

RESULTS

Seven patients underwent biopsy. Preoperative MRI revealed a lesion extending beyond the pons in five patients and a focal enhancing lesion in four. Two patients had both of these. Open biopsy was performed via midline suboccipital approach in six patients and retrosigmoid approach in one. No intraoperative complications were observed. Histopathological examination revealed diffuse brainstem glioma in five patients, primitive neuroectodermal tumor (PNET) in one, and pilocytic astrocytoma in one. In the case with PNET, chemotherapy and radiotherapy were effective and the patient had been stable for 12 months without recurrence. The patient with pilocytic astrocytoma did not undergo radiotherapy and has been stable without regrowth of the tumor for 9 months.

CONCLUSIONS

Open biopsy of intrinsic brainstem lesions is considered to be safe and effective for selecting an appropriate course of therapy. Patients with intrinsic pontine lesions which extend beyond the pons or with localized enhancing portion seem to be benefited from the biopsy.

Interstitial stereotactic radiosurgery of pilocytic astrocytomas in paediatric patients

OBJECTIVE

To evaluate the clinical presentation, tumour response, clinical improvement and complications in 12 children and young people with a pilocytic astrocytoma, WHO I grade 1, who were treated with interstitial radiosurgery using Iodine-125 seed implants.

PATIENTS AND METHODS

Retrospective analysis of 12 patients aged under 18 years (mean 8.4 years, ranging from 8 months to 17 years of age) with a pilocytic astrocytoma treated between 1993 and 2006. Iodine-125 seeds were used as temporary implants with low-dose rate (<or=10 cGy/h) and a calculated reference dose of 60 and 100 Gy to the outer ring of the tumour.

RESULTS

There was no perioperative mortality. Two patients worsened transiently, but thereafter each patient improved clinically. Eleven out of 12 tumours shrank after the treatment. The mean volume of the tumours before implantation was 17.9 cm(3). and was reduced to 60% of this volume at 6 months, to 26.5% at 12 months, to 8% at 24 months, and was less than 1% at 30-36 months One patient underwent a reimplantation to treat a recurrence 3 years after the initial treatment. Ten patients were alive 2 years after the first intervention. In the longest surving patient, there was no evidence of progression after 13.4 years of follow up.

Stereotactic techniques in managing pediatric brain tumors

Stereotactic techniques available for managing pediatric brain tumors include not only stereotactic biopsy but also stereotactic craniotomy, brachytherapy, and stereotactic radiosurgery. This paper illustrates the use of these techniques in brain tumors in children over a 2-year period at Children's Hospital, Boston. Stereotactic biopsy was used in six cases of deep-seated tumor, with successful tissue diagnosis in all six. Stereotactic craniotomy, in which excision of a mass was done in the stereotactic frame with computed tomography-guided localization and control, was employed in three children. Interstitial radiation using implanted 125I seeds was carried out in two children with malignant astrocytomas: in both it provided good local control but there was later distant recurrence. Stereotactic radiosurgery with a modified linear accelerator was used in eight children as adjunctive therapy for local control. These cases illustrate the versatility of stereotactic techniques involved in a comprehensive approach to pediatric brain tumors.

Stereotactic approach to intracranial lesions

The diagnostic and therapeutic approach to intracranial lesions must be different considering the different possibilities offered by the various methods. The diagnostic reliability and safety of stereotactic biopsy are often indispensable in order to optimize the subsequent therapy. The results obtained in selected pathologies allow us to propose the stereotactic approach to treat: -various kind of cysts by aspiration and/or Beta endocavitary radiation therapy; -blood or abscessual collections that can be aspirated in a similar way; -arterio venous malformations or tumours by radiosurgery; -tumours by brachicurietherapy or by computer assisted stereotactic surgery. We present some cases treated at the C.H.S.A. of Paris and at the C.H.R.U. of Grenoble utilizing Talairach methodology.

Intracranial tumors during the 1st year of life

Twenty-eight patients with intracranial tumors symptomatic during the 1st year of life were managed from January 1970 to March 1988. Supratentorial location (19 cases) was dominant over the infratentorial. The most common histological type was astrocytoma; choroid plexus papilloma and ependymal tumors followed in frequency. Twenty-two infants (78.6%) had associated hydrocephalus. Macrocrania, vomiting, delayed milestones, and behavioral disturbances were the chief clinical manifestations. Four patients were admitted in extremely deteriorated condition and died preoperatively. Twenty cases underwent surgery for tumor removal with a 1-month mortality rate of 20%. Tumor excision provided permanent relief of hydrocephalus in the majority of the surviving cases. Five patients received conventional radiotherapy. Stereotactic brachytherapy yielded an excellent result in 1 case. Overall 13 cases are currently alive; 6 of them have survived longer than 6 years. Fourteen of the 15 patients who were dead at follow-up succumbed within 1 year after diagnosis.

Differential diagnosis between tumoural and non-tumoural intracranial lesions in children: a stereotactic approach

The rational management of intracranial lesions should be based on the exact definition of the nature of the lesions and, when it is possible, on their spatial definition. Since External Radiotherapy (ERT) and cytostatic therapy are not free of undue effects, especially in children, such treatments should be used only when a "sure" diagnosis is obtained. The aim of this paper is to study the results allowed by the Talairach's stereotactic methodology in children. During the period January 1979-December 1986, 704 stereotactic procedures including serial biopsies, were performed at the S. Anne Hospital in Paris. One hundred forty-eight procedures (21%) concerned 134 children (78 M; 56 F) aged from 2 to 16 years. The interval between the occurrence of the first clinical symptoms and the stereotactic procedures varied between 1 and 180 months (m: 24 m). Fifty-two (40%) had previous therapeutic procedures without precise diagnosis. The lesions were hemispheric in 46 (34%) and deep seated in 88 (66%). The serial stereotactic biopsies proved the existence of a non-tumoural lesion in 20 children (14.9%): (cryptic vascular malformation: 5, cortical dysplasia: 3, haematoma: 3, ischaemia: 1, granuloma: 1, degenerative pathology: 2, cicatrix: 2, post-ERT alterations: 1, arachnoidal cyst: 2). Four were in the brain stem. In 3 patients (2%), a precise diagnosis was not obtained. The CT scan characteristics of the 20 non-tumoural lesions did not permit to establish a precise differential diagnosis. The therapeutic management was adapted to the diagnosis, avoiding potentially dangerous procedures in the 20 non-tumoural lesions.