Publications by authors named "Ralph Lehrke"

Brainstem metastases (BSM) present a significant neuro-oncological challenge, resulting in profound neurological deficits and poor survival outcomes. Stereotactic radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) offer promising therapeutic avenues for BSM despite their precarious location. This international multicenter study investigates the efficacy and safety of SRS and FSRT in 136 patients with 144 BSM treated at nine institutions from 2005 to 2022.

View Article and Find Full Text PDF

(1) Background: Infections in deep brain stimulation (DBS) hardware, while an undesired complication of DBS surgeries, can be effectively addressed. Minor infections are typically treated with wound revision and IV antibiotics. However, when visible hardware infection occurs, most centers opt for complete removal, leaving the patient in a preoperative state and necessitating post-removal care.

View Article and Find Full Text PDF

Background: Foramen magnum meningiomas (FMMs) represent a considerable neurosurgical challenge given their location and potential morbidity. Stereotactic radiosurgery (SRS) is an established non-invasive treatment modality for various benign and malignant brain tumors. However, reports on single-session or multisession SRS for the management and treatment of FMMs are exceedingly rare.

View Article and Find Full Text PDF

Objectives: Deep brain stimulation (DBS) is known to interfere with electrocardiographic (ECG) examinations. In emergency situations, such electrical interferences can not only thwart ECG diagnostics, but even induce an ECG pattern that causes the emergency medical service to initiate inadequate or even harmful therapy. Aim of this prospective study was to evaluate factors influencing ECG interpretation in DBS and to evaluate the susceptibility of ECG criteria 'frequency', 'rhythm', 'regularity', 'QRS-configuration', and 'ST-segment' on neurostimulation.

View Article and Find Full Text PDF

Background: The rates of incomplete surgical resection for pituitary macroadenomas with cavernous sinus invasion are high. In growth hormone-producing adenomas, there is a considerable risk for persistent acromegaly. Thus, effective treatment options are needed to limit patient morbidity and mortality.

View Article and Find Full Text PDF

Background: Glomus jugulare tumors (GJTs) are challenging to treat due to their vascularization and location. This analysis evaluates the effectiveness and safety of image-guided robotic radiosurgery (RRS) for GJTs in a multicenter study and reviews the existing radiosurgical literature.

Methods: We analyzed outcome data from 101 patients to evaluate local control (LC), changes in pretreatment deficits, and toxicity.

View Article and Find Full Text PDF

Background: Deep brain stimulation (DBS) indications include movement disorders, psychiatric affections, or epilepsy in which patients risk social isolation heightened by abnormal motions or behavioral patterns. Further stigmatization after DBS surgery from head shaving, visible scarring, or disfigurement from bulky lead insertion points should be avoided.

Objective: We present a cosmetically optimized, adapted submammarian approach for DBS neurostimulator implantation that leaves the décolletage untouched.

View Article and Find Full Text PDF

Thalamic deep brain stimulation is a mainstay treatment for severe and drug-refractory essential tremor, but postoperative management may be complicated in some patients by a progressive cerebellar syndrome including gait ataxia, dysmetria, worsening of intention tremor and dysarthria. Typically, this syndrome manifests several months after an initially effective therapy and necessitates frequent adjustments in stimulation parameters. There is an ongoing debate as to whether progressive ataxia reflects a delayed therapeutic failure due to disease progression or an adverse effect related to repeated increases of stimulation intensity.

View Article and Find Full Text PDF

Purpose: Although microsurgery remains the first-line treatment, gross total resection of cystic craniopharyngeomas (CP) is associated with significant morbidity and mortality and the addition of external irradiation to subtotal resection proves to achieve similar tumor control. However, concern regarding long-term morbidity associated with external irradiation in children still remains. With this retrospective analysis, the authors emphasize intracavitary brachytherapy using phosphorus-32 (P-32) as a treatment option for children with cystic CP.

View Article and Find Full Text PDF

This paper summarizes outcomes of a single-center study of intracavitary brachytherapy (IBT) with stereotactically applied phosphorus-32 ((32)P) colloid for treatment of cystic craniopharyngiomas. We assessed its efficacy and safety, on the basis of clinical and radiological outcomes in one of the largest reported patient series. Between 1992 and 2011, 53 patients were treated with IBT, 14 without previous treatment and 39 who had previously been treated for recurrent cysts.

View Article and Find Full Text PDF

Purpose: Resection is generally considered the gold standard for treatment of low-grade (WHO grades I and II) gliomas (LGGs) in childhood. However, approximately 30% to 50% of these tumors are inoperable because of their localization in highly eloquent brain areas. A few reports have suggested stereotactic brachytherapy (SBT) with implantation of iodine-125 ((125)I) seeds as a safe and effective local treatment alternative.

View Article and Find Full Text PDF

Background: A patient controller (PC) is an optional device for patients with deep brain stimulation (DBS) to have limited control of their stimulator system.

Objectives: We investigated the impact of a PC on DBS safety, most notably the handling/prevention of unexpected DBS failure in patients with Parkinson's disease (PD).

Methods: PD patients with subthalamic DBS were educated in the use of a PC.

View Article and Find Full Text PDF

Purpose: To evaluate the efficacy of interstitial radiosurgery (IRS) for pineal parenchymal tumors (PPTs).

Patients And Methods: 18 consecutively admitted patients (twelve male and six female, age range 6-68 years, median age 34 years) with PPTs (eight pineocytomas, ten malignant PPTs) were treated at the authors' institution with IRS using stereotactically guided iodine-125 seed implantation ((125)I-IRS) as either primary or salvage therapy. The cumulative tumor surface dose ranged from 40 to 64 Gy.

View Article and Find Full Text PDF

Deep-brain stimulation of the subthalamic nucleus and internal globus pallidus are both surgical options in advanced Parkinson's disease. The best target is still debated with data suggesting better motor outcome in subthalamic stimulation but higher rates of psychiatric problems. Failure of pallidal stimulation within the first 2 years has been described.

View Article and Find Full Text PDF

Objective: In patients with Parkinson's disease (PD) the effect of thalamic stimulation on tremor pathophysiology remains largely unclear. By recording local field potentials (LFPs) in the subthalamic nucleus (STN) while stimulating the nucleus ventralis intermedius thalami (VIM), information of the stimulation effects should be gained.

Methods: We had the unique opportunity to intraoperatively record LFPs of the STN in a patient with PD while stimulating the VIM.

View Article and Find Full Text PDF

Background: High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves motor functions in those with Parkinson disease but may worsen frontal functions such as verbal fluency (VF). In contrast, low-frequency DBS leads to deterioration of motor functions. It is not known whether low-frequency STN DBS also has an effect on frontal functions.

View Article and Find Full Text PDF

Background: A prospective study was conducted to assess the efficacy and side effects of linear accelerator (LINAC)-based radiosurgery (RS) performed with a reduced dose of therapeutic radiation for patients with surgically inaccessible pituitary macroadenomas.

Methods: From August 1990 through January 2004, 175 patients with pituitary macroadenomas were treated with LINAC-RS according to a prospective protocol. To minimize the risk for radiation-induced damage of the pituitary function, the therapeutic dose to be applied was limited to 20 grays.

View Article and Find Full Text PDF

Objective: To assess the accuracy of the stereotactic implantation procedure of catheters containing I-125 seeds in brain tumours and investigate the effect of catheter deviations on the dose distribution in patients.

Methods: A randomised sample (n = 37) of all patients treated with I-125 seeds in our department between 6/1994 and 2/2002 was examined. Intraoperative X-ray images were used to measure deviations of implanted I-125 seed catheters from their planned positions and the influence on dose conformity, tumour surface dose and dose burden of surrounding healthy brain tissue was determined.

View Article and Find Full Text PDF

Recently, a pathological oscillatory network at 10 Hz including several motor areas was described in patients with idiopathic Parkinson's disease (PD). In 7 PD patients, we tested the clinical effect of subthalamic nucleus (STN) stimulation at varying frequencies 1 to 3 years after implantation of electrodes. STN stimulation at 10 Hz induced significant worsening of motor symptoms, especially akinesia, compared with no stimulation and therapeutic stimulation (> or =130 Hz).

View Article and Find Full Text PDF

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a highly effective surgical treatment in patients with advanced Parkinson's disease (PD). Because the STN has been shown to represent an important relay station not only in motor basal ganglia circuits, the modification of brain areas also involved in non-motor functioning can be expected by this intervention. To determine the impact of STN-DBS upon the regional cerebral metabolic rate of glucose (rCMRGlc), we performed positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) in eight patients with advanced PD before surgery as well as in the DBS on- and off-conditions 4 months after electrode implantation and in ten age-matched healthy controls.

View Article and Find Full Text PDF

Purpose: To investigate acute and late tissue reactions following intracerebral implantation of three different biodegradable DL-polylactids: Resomer R104 + R203 (1 + 1) (SU48), Resomer R203 (SU49), and DL-polylactid-co-trimethylencarbonat (SU50).

Methods: Polylactide (PL) rods and small pieces of silicon (control) were stereotactically implanted in the forebrain of 60 Wistar rats. Twenty-eight, 70, and 112 days after implantation, five animals of each group (SU48, SU49, SU50, control) were sacrificed.

View Article and Find Full Text PDF

Object: The goal of this study was to relate the degree of clinical improvement and that of energy consumption to the anatomical position of electrode poles used for long-term stimulation.

Methods: The authors conducted a retrospective analysis of 15 consecutive patients in whom targeting of the subthalamic nucleus (STN) had been performed using ventriculography, three-dimensional (3D) magnetic resonance (MR) imaging, and 3D computerized tomography, together with macrostimulation and teleradiographic control of the electrode position. In these patients the follow-up period ranged from 6 to 12 months.

View Article and Find Full Text PDF