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Karl Kothbauer

Publications and source records attributed to Karl Kothbauer.

9 recordsLinked to original sources
PubMed2006

Monitoring of muscle motor evoked potentials during cerebral aneurysm surgery: intraoperative changes and postoperative outcome.

OBJECT: The authors in this study evaluated muscle motor evoked potentials (MMEPs) elicited by transcranial electrical stimulation (TES) and direct cortical stimulation as a means of monitoring during cerebral aneurysm surgery. The analysis focused on the value and frequencies of any intraoperative changes and their correlation to the postoperative motor status. METHODS: One hundred nineteen patients undergoing surgery for 148 cerebral aneurysms were included in the study. Muscle motor evoked potentials were elicited by a train of five constant-current anodal stimuli with an individual pulse duration of 0.5 msec and a stimulation rate of 2 Hz. Stimulation intensity was up to 240 mA for TES and up to 33 mA for direct cortical stimulation. The MMEPs were continuously recorded from the abductor pollicis brevis and tibialis anterior muscles bilaterally and from the biceps brachii and extensor digitorum communis muscles contralateral to the surgical side. The motor status was evaluated immediately after surgery and 7 days later. In 97% of the patients MMEPs were recordable for continuous neurophysiological monitoring of the vascular territory of interest throughout the surgery. In 14 patients significant intraoperative MMEP changes occurred, resulting in a transient motor deficit in one patient and a permanent motor deficit in six. The permanent loss of MMEPs in three patients was followed by a permanent severe motor deficit in one patient and severe clinical deterioration in the other two. CONCLUSIONS: Data in this study demonstrated that MMEPs are a useful means of intraoperative neurophysiological monitoring of motor pathway integrity and predicting postoperative motor status. The intraoperative loss of MMEPs reliably predicts both severe and permanent postoperative motor deficits.

Adolescent↗
PubMed2005

Endoscopic third ventriculostomy for tumor-related hydrocephalus in a pediatric population.

OBJECT: Endoscopic third ventriculostomy (ETV) has become a common alternative for managing hydrocephalus in select patients. Nevertheless, there is still controversy regarding the indications for ETV as the primary procedure, given its variable success rates. The purpose of this study is to review the authors' experience with ETV for a variety of patients. METHODS: A total of 43 children underwent ETV between July 1992 and June 2003. Their medical records, operative reports, and imaging studies, when available, were retrospectively reviewed with regard to outcome, complications, and patency rate. Treatment failure was defined as the need to place a shunt within 4 weeks of performing ETV in the patient. There were 20 male and 23 female patients with a mean age of 9.6 years (range 8 weeks-21 years). The overall success rate was 69.8%, and the mean follow-up duration was 24.6 months. Six patients underwent eight repeated ETVs at a mean interval of 25 months, with a patency rate of 62.5% after the second procedure. Only two surgeries were aborted for anatomical reasons. The highest success rates (100% in each instance) were achieved for obstructive hydrocephalus resulting from midbrain/tectal tumor (four patients) and pineal tumor (three patients). CONCLUSIONS: The ETV procedure is an effective management tool for obstructive hydrocephalus in children. It should be considered the primary procedure, rather than ventriculoperitoneal shunts, in carefully selected children. The success rate is dependent on the origin of the hydrocephalus.

Adolescent↗
PubMed2005

Spinal solitary fibrous tumors: a series of four patients: case report.

OBJECTIVE AND IMPORTANCE: Intraspinal solitary fibrous tumors, which are rare mesenchymal tumors, have previously been reported as case reports. We review our experience and, to our knowledge, the first small institutional series with respect to clinical presentation, diagnosis, surgical management, pathohistological analysis, progression-free survival, and long-term outcome. CLINICAL PRESENTATION: In this retrospective review, four patients (three male and one female) ranging in age from 17 to 59 years (mean, 38.5 yr) had spinal solitary fibromas located throughout the spinal canal. Three tumors were located in the thoracic region and one in the cervical spine. All patients presented with pain and paresthesia. Two patients had an associated spinal deformity. All had gross total resection as confirmed by postoperative imaging studies. INTERVENTION: All four patients underwent surgical treatment for spinal solitary fibromas. None of these patients underwent irradiation or chemotherapy after surgery at our center; therefore, outcome was attributed to surgery alone. There were no surgical deaths, and the 5-year actuarial survival rate was 100%. At the most recent follow-up examination, neurological function was stable or improved in 90% of patients. CONCLUSION: Patients with solitary fibrous tumors have a long survival. These tumors have an indolent course, and radiotherapy or chemotherapy seems to be unnecessary.

Adolescent↗
PubMed2005

Motor evoked potential monitoring during cerebral aneurysm surgery: technical aspects and comparison of transcranial and direct cortical stimulation.

OBJECTIVE: This study evaluates technical aspects, handling, and safety of intraoperatively applied transcranial electrical stimulation (TES) and direct cortical stimulation (DCS) for eliciting muscle motor evoked potentials (mMEPs) during cerebral aneurysm surgery. METHODS: In 119 patients undergoing cerebral aneurysm surgery, mMEPs were evoked by a train of five stimuli with individual pulse duration of 0.5 milliseconds, a repetition rate of 2 Hz, and constant current anodal stimulation. The maximal stimulation intensity was 240 mA for transcranial and 33 mA for direct stimulation. mMEPs were recorded continuously from the abductor pollicis brevis, from tibial anterior muscles bilaterally, and from the biceps brachii and extensor digitorum communis muscles contralateral to the side operated on. RESULTS: In 118 (99%) of 119 patients, transcranially evoked mMEPs were monitorable for the vascular territory of interest. DCS was performed successfully in 95 (95%) of 100 patients. In 86 (99%) of 87 patients with internal carotid artery, middle cerebral artery, or posterior circulation aneurysms, mMEPs from upper-extremity muscles were obtained with DCS. In 11 (55%) of 20 patients with anterior communicating artery, anterior cerebral artery, or pericallosal aneurysms, mMEPs from the lower-extremity muscles could be recorded. The incidence of seizures was 0.84% for TES and 1% for DCS. Minor and inconsequential subdural bleeding after positioning of the strip electrode occurred in 2%. CONCLUSION: The cogent comprehensive combination of transcranial and direct cortical electrical stimulation allows for the continuous mMEP monitoring of the cerebral vascular territory of interest in 99% of the patients with cerebral aneurysms. Unwarranted effects of electrode placement and stimulation are rare and without clinical consequences.

Adolescent↗
PubMed2005

Meningioangiomatosis without neurofibromatosis: a clinical analysis.

OBJECT: Meningioangiomatosis is an uncommon clinical entity. This lesion has been reported at time of autopsy in patients with neurofibromatosis (NF) and in case reports of patients without NF Type 2 (NF2). The authors report a series of six patients with meningioangiomatosis who do not have NF2 and describe the clinical presentation, diagnosis of disease, and treatment. They also review the literature concerning this entity. METHODS: Six patients with meningioangiomatosis were treated at the authors' institutions from 1994 to 2001. The mean age of the patients was 10.7 years (range 5-14 years). All of the children presented with a seizure disorder. Surgery was performed in all children, and a gross-total resection was accomplished. All patients exhibited clinical improvement. At last follow up (mean 6.3 years) all patients are free of seizures and are not taking anticonvulsant medications. No signs of recurrence have been noted on imaging studies. CONCLUSIONS: The authors advocate a gross-total resection of meningioangiomatosis for the treatment of seizure disorder in this population.

Adolescent↗
PubMed2004

The refractory period of fast conducting corticospinal tract axons in man and its implications for intraoperative monitoring of motor evoked potentials.

OBJECTIVE: To determine the absolute and relative refractory period (RRP) of fast conducting axons of the corticospinal tract in response to paired high intensity (HI or supramaximal) and moderate intensity (MI or submaximal) electrical stimuli. The importance of the refractory period of fast conducting corticospinal tract axons has to be considered if repetitive transcranial electrical stimulation (TES) is to be effective for eliciting motor evoked potentials (MEPs) intraoperatively. METHODS: Direct (D) waves were recorded from the epidural space of the spinal cord in 14 patients, undergoing surgical correction of spinal deformities. To assess the absolute and RRPs of the corticospinal tract, paired transcranial electrical stimuli at interstimulus intervals (ISI) from 0.7 to 4.1 ms were applied. Recovery of conditioned D wave at short (2 ms) and long (4 ms) ISI was correlated with muscle MEP threshold. The refractory period for peripheral nerve was tested in comparison to that for the corticospinal tract. In four healthy subjects sensory nerve action potentials of the median nerve were studied after stimulation with paired stimuli. RESULTS: HI TES revealed a mean duration of 0.82 ms for the absolute refractory period of the corticospinal tract, while MI stimulation resulted in a mean refractory period duration of 1.47 ms. Stimuli of HI produced faster recovery of D wave amplitude during the RRP. Furthermore, short trains of transcranial electrical stimuli did not elicit MEPs when D wave showed incomplete recovery. A similar influence of stimulus intensity on recovery time was found for the refractory period of peripheral nerve. CONCLUSIONS: The recovery of D wave amplitude is dependent upon stimulus intensity. High intensity produces fast recovery. This is an important factor for the generation of MEPs. When HI TES is used to elicit MEPs, short and long ISIs are equally effective. When MI TES is used to elicit MEPs, only a long ISI of 4 ms is effective.

Action Potentials↗
PubMed2004

Chronic subdural hematoma as a complication of endoscopic third ventriculostomy.

BACKGROUND: Endoscopic third ventriculostomy has become a popular alternative to ventricular shunts for noncommunicating hydrocephalus. Although endoscopic third ventriculostomy is a safe procedure, several complications related to this procedure have been reported in the literature. The authors present a rare case of symptomatic bilateral subdural hematomas after an uneventful endoscopic third ventriculostomy. CASE DESCRIPTION: A 51-year-old male patient presented with symptoms of obstructive hydrocephalus, headaches and memory disturbance. Magnetic resonance imaging demonstrated hydrocephalus secondary to aqueductal stenosis. An endoscopic third ventriculostomy was performed. The patient was discharged home in several days without complication. He then presented with headaches 3 weeks following surgery. A computed tomography study demonstrated bilateral subdural hematomas. These were treated with burr hole evacuation and drainage. Postoperatively, his headaches improved. At last follow-up he remains symptom-free and has radiographic evidence of a patent ventriculostomy. CONCLUSION: This case confirms chronic subdural hematoma formation is a possible complication following third ventriculostomy. Patients should be followed closely for possible subdural hematoma formation.

Hematoma, Subdural, Chronic↗
PubMed2002

Endoscopic third ventriculostomy in patients with cerebrospinal fluid infection and/or hemorrhage.

OBJECT: In this study the authors evaluate the safety, efficacy, and indications for endoscopic third ventriculostomy (ETV) in patients with a history of subarachnoid hemorrhage or intraventricular hemorrhage (IVH) and/or cerebrospinal fluid (CSF) infection. METHODS: The charts of 101 patients from seven international medical centers were retrospectively reviewed; 46 patients had a history of hemorrhage, 42 had a history of CSF infection, and 13 had a history of both disorders. All patients experienced third ventricular hydrocephalus before endoscopy. The success rate for treatment in these three groups was 60.9, 64.3, and 23.1%, respectively. The follow-up period in successfully treated patients ranged from 0.6 to 10 years. Relatively minor complications were observed in 15 patients (14.9%), and there were no deaths. A higher rate of treatment failure was associated with three factors: classification in the combined infection/hemorrhage group, premature birth in the posthemorrhage group, and younger age in the postinfection group. A higher success rate was associated with a history of ventriculoperitoneal (VP) shunt placement before ETV in the posthemorrhage group, even among those who had been born prematurely, who were otherwise more prone to treatment failure. The 13 premature infants who had suffered an IVH and who had undergone VP shunt placement before ETV had a 100% success rate. The procedure was also successful in nine of 10 patients with primary aqueductal stenosis. CONCLUSIONS: Patients with obstructive hydrocephalus and a history of either hemorrhage or infection may be good candidates for ETV, with safety and success rates comparable with those in more general series of patients. Patients who have sustained both hemorrhage and infection are poor candidates for ETV, except in selected cases and as a treatment of last resort. In patients who have previously undergone shunt placement posthemorrhage, ETV is highly successful. It is also highly successful in patients with primary aqueductal stenosis, even in those with a history of hemorrhage or CSF infection.

Adolescent↗