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H P Richter

Publications and source records attributed to H P Richter.

At least 19 recordsLinked to original sources
PubMed2006

[Subcranial resection of malignant tumors infiltrating the anterior skull base].

BACKGROUND: Survival and quality of life after subcranial resection of malignant tumors infiltrating the anterior skull base should be evaluated. METHODS: Data were acquired retrospectively from patient charts and by telephone interview. Quality of life was assessed with the EORTC QLQ30 and H&N35 modules. RESULTS: From 1996 to 2004, 19 patients (mean age 52 years, 4 woman, 15 men) were surgically treated via a subcranial approach. Fifteen patients suffered from advanced carcinoma, 3 from advanced esthesioneuroblastoma, and 1 patient had a fibrosarcoma. Fifteen patients received adjuvant radiotherapy. During the mean follow-up period of 44 months (12-109 months), 6 patients died, 1 unrelated to the tumor. The probability to survive 5 years was 50 %, the mean survival time was 72 months. Anosmia was reported by 18 of 19 patients. A tension pneumocephalus was observed in 2 patients, one with lethal outcome, decreased vision in 1 patient, loss of vision in 1, persisting diplopia in 1, deep wound infections in 2, and CSF leak in 2 patients. Quality of life was assessed on the average 36 months following end of therapy and did not differ substantially from other patients with head-neck malignancies. CONCLUSION: Most, malignant tumors infiltrating the anterior skull base can be treated curatively. The treatment outcome is well comparable to other head and neck tumors of corresponding stage.

Adenocarcinoma↗
PubMed2002

Cranial neuronavigation with direct integration of (11)C methionine positron emission tomography (PET) data -- results of a pilot study in 32 surgical cases.

BACKGROUND: MRI detects small intracranial lesions, but has difficulties in differentiating between tumour, gliosis and edema. (11)C methionine-PET may help to overcome this problem. For its appropriate intra-operative use, it must be integrated into neuronavigation. We present the results of our pilot study with this method. METHOD: 32 patients with 34 intracranial lesions detected by MRI underwent additional (11)C methionine-PET, because the pathophysiological behaviour or the tumour delineation was unclear. All lesions were treated surgically. In 25 patients PET data could be integrated directly into cranial neuronavigation. FINDINGS: (11)C methionine uptake was observed in 27/34 lesions, 26 of them were tumours: 14 malignant and 7 benign gliomas, 3 gliomas without further histological typing, one Ewing sarcoma and one non-Hodgkin lymphoma. Only one (11)C methionine positive lesion was non-tumourous: it was staged as post-irradiation necrosis in a patient operated on for a malignant glioma. 3/7 (11)C-methionine negative lesions were classified as gliosis (n=2) and M. Whipple (n=1), but 4/7 were tumours: 2 astrocytomas WHO(degrees)II, 1 DNT and one astrocytoma WHO(degrees)III. The sensitivity of (11)C methionine-PET was 87%, the specificity 75%, the positive predictive value 96% and the negative predictive value 43%. In all tumourous cases with positive tracer uptake the borderline area of the tumour was better defined by (11)C methionine-PET than by MRI. INTERPRETATION: A positive (11)C methionine-PET is highly suspicious of a tumour, a negative one does not exclude it. (11)C methionine-PET seems to be more sensitive than MRI for differentiating between tumour and edema or gliosis. Simultaneous integration MRI and (11)C methionine-PET into cranial neuronavigation can facilitate cross total tumour removal in glioma surgery.

Brain Edema↗
PubMed2001

In vivo experiences with frameless stereotactically guided screw placement in the spine--results from 75 consecutive cases.

Whereas cranial neuronavigation is widely accepted as a helpful tool, larger series of the in vivo application of spinal neuronavigation do not exist. In the following we report our 4-year experience with spinal navigation in 75 consecutive cases for dorsal transpedicular screw placement. Seventy-five patients were planned for operation employing anatomical reference points defined on a 2-mm high resolution CT. We used single vertebra registration and surface matching. With the above methods, the mean registration deviation ranged from 0.18 mm (cervical spine) to 0.31 mm (lumbar spine). All our screws in the upper cervical spine were navigated correctly (17 patients), thus improving markedly the surgical outcome. The results were not as promising in the lumbar area. In only 84% was navigation reliable. The reason was the lack of a practicable tracking tool. Spinal neuronavigation based on anatomical reference points is able to improve the results in transpedicular screwing, especially in the cervical spine. The lack of a practicable tracking tool still hinders its use in routine clinical application.

Bone Screws↗
PubMed2001

Case reports of symptomatic metastases in four patients with primary intracranial gliomas.

Four patients with primary intracranial high-grade gliomas are reported. Three of them developed spinal symptoms and signs generated by spinal metastases a few months after first diagnosis, the last patient developed an extraspinal metastasis in cervical lymph nodes. The spinal metastasis of a 30 years old patient was located intradurally at L5/S1, in the second patient at level L3, the third patient presented with multiple metastases in the cervical, thoracic and lumbar spine. Previously reported cases are reviewed, are discussed in the light of our own observations and analysed for the various therapeutic options.

Adult↗
PubMed2001

Multimodal cranial neuronavigation: direct integration of functional magnetic resonance imaging and positron emission tomography data: technical note.

OBJECTIVE: This is the first report of the direct integration of functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) data into cranial neuronavigation. METHODS: In a patient with a left precentral oligodendroglioma (World Health Organization Grade III), the Zeiss MKM system (Carl Zeiss Co., Oberkochen, Germany) was used for navigation based on thin-slice, T1-weighted, contrast-enhanced magnetic resonance imaging (MRI) scans. fMRI and methionine PET data were integrated by landmark matching, with reference to skin fiducials. RESULTS: The inaccuracy of the image fusion between fMRI and T1-weighted MRI data was 1.7 mm, that between PET and T1-weighted MRI data was 4.3 mm, and that for the subsequent registration of the navigation was 1.2 mm. The correct fMRI localization of the precentral gyrus was intraoperatively verified by cortical somatosensory evoked potential (phase-reversal) monitoring. Although the tumor was not clearly defined in the MRI scans, [11C]methionine PET demonstrated a clear tumor border, enabling us to achieve gross total tumor removal without postoperative functional deficits. CONCLUSION: Functional neuronavigation permits observation and preservation of relevant brain areas. Other functional areas (such as short-term memory areas) that can be detected only by fMRI might also warrant future monitoring. The simultaneous integration of fMRI and PET data adds a new dimension to cranial neuronavigation, enabling the observation of tumors in relation to functional cortical areas (in our case, the motor strip).

Brain↗
PubMed2001

Evaluation of iatrogenic lesions in 722 surgically treated cases of peripheral nerve trauma.

OBJECT: The purpose of this study was to discover the number and types of iatrogenic nerve injuries that were surgically treated during a 9-year period at a relatively busy nerve center. The specific nerves involved, their sites of injury, and the mechanisms of injury were also documented. METHODS: The authors retrospectively evaluated the surgically treated iatrogenic lesions by reviewing case histories, operative reports, and follow-up notes in 722 cases of trauma. These cases were treated between January 1990 and December 1998 because of pain, dysesthesias, and sensory and/or motor deficits. latrogenic injury was a much larger category of trauma than predicted. One hundred twenty-six (17.4%) of the 722 surgically treated cases were iatrogenic in origin. Most of these injuries occurred during a previous operation. To a major extent, nerves of the extremities were affected, and a relatively large number of injuries occurred in the neck and groin. Incidence was highest in the spinal accessory nerve (14 cases), the common peroneal nerve (11 cases), the superficial radial nerve (10 cases), the genitofemoral nerve branches (10 cases), and the median nerve (nine cases). At least two thirds of the patients did not undergo surgery for the iatrogenic injury within an optimal time interval due to delayed referral. Follow-up data were available in 97 of the 126 patients. Surgical outcomes demonstrated improvement in 70% of patients. Operative results were especially favorable in patients suffering from iatrogenic injuries to the accessory and superficial sensory radial nerves. CONCLUSIONS: latrogenic injuries should be corrected in a timely fashion just like any other traumatic injury to nerve.

Extremities↗
PubMed2001

Results of applying ADCON-L gel after lumbar discectomy: the German ADCON-L study.

OBJECT: Failed-back syndrome is still an unsolved problem. Use of ADCON-L gel, already commercially available, has been proven to reduce postoperative scarring in animal experiments. The authors of two controlled clinical studies have also shown positive results when applying the gel. They did not, however, establish patient-oriented endpoints. The authors report a study of ADCON-L in which they focus on patient-oriented endpoints. METHODS: Patients with lumbar disc herniation were randomized to an ADCON-L-treated or control group. Therapeutic success was evaluated using the validated Hannover Questionnaire on Activities of Daily Living (FFbH) 6 months after surgery. The study took place between November 14. 1996, and April 20, 1998, in eight neurosurgical centers in Germany. A total of 398 patients was recruited; 41 patients dropped out during follow up. The mean functional FFbH score (100 points = all activities are possible without problem; 0 points = no activity is possible) was 78.5 points in the ADCON-L-treated group compared with 80 points in the control group. Furthermore, in terms of secondary outcome variables, the ADCON-L group did not have an advantage over the control group. Only the mean magnetic resonance imaging score showed a slight advantage of ADCON-L over the control group. CONCLUSIONS: The authors found no positive effect of treatment with ADCON-L gel in patients in whom one-level lumbar microdiscectomy was performed. Because of its rather large sample size and its homogeneity, the study had sufficient power to detect even small differences between the two groups.

Activities of Daily Living↗
PubMed2000

[Effect of microneurosurgical operation in acoustic neurinoma on symptoms of vertigo and tinnitus].

After exstirpation of an acoustic neuroma one trends to concentrated on the preservation of hearing and facial function. But how does the surgical removal for an acoustic neuroma, influence the symptoms of tinnitus and vertigo? Our report follows a retrospective evaluation of 78 patients. Based on these results we will also discuss aspects of the origin of these symptoms. Our patients suffered from tinnitus at a rate of 73% preoperatively and 59% postoperatively. With increasing tumor size tinnitus occurred less often, therefore we considered the size of the tumor exclusively. Also, an intraoperative dissection of the cochlear nerve often did not result in an improvement of the symptoms. Vertigo was stated prooperatively in 44% of the cases, postoperatively in 22%. Again as with tinnitus, there was an inverse relationship between the size of the tumor and the severity of the symptoms. In conclusion a deafferention-like syndrome has to be considered as the major causative factor for the tinnitus in patients with acoustic neuromas. However, in the vertigo cases, the symptoms seem to be caused vestibularily due to the increasing tumor and then after a temporary compensation a cerebellar ataxia occurred which the patients often perceive as vertigo.

Adolescent↗
PubMed2000

[Epidemiology of disk surgery in Germany].

Actually, there are no valid epidemiologic data concerning intervertebral disk surgery available for Germany. Using resources of official statistical information we estimated the incidence of inpatient and outpatient disk surgery in Germany during last 6 years: The incidence for degenerative intervertebral disk surgery in Germany is about 87 operations per 100,000 inhabitants and year. There is no significant increase in the last five years, but there is a tendency to more outpatient disk surgery. Presently 16% of disk surgery is done in a outpatient procedure. Comparing with other European countries there are similar frequencies of disk surgery, contradictory in the United States there was a huge increase of the incidence for disk surgery since 1980.

Ambulatory Surgical Procedures↗
PubMed2000

Neurosurgery without shaving: indications and results.

The objective of the investigation was to prevent the stigmatizing effect of a totally or partially shaved head with openly visible signs of a head operation, easing the reintegration of the patient into his daily life. After extended surface cleaning with a colourless, regular skin disinfection liquid (undyed isopropanol/dibrom/propylenglycol solution) the hair was combed apart from the incision line before draping. Wound closure was performed as usual, taking care to remove meticulously hair from the wound. To aid closure we made use of a 20% chlorhexidine jelly that holds the hair away from the incision. A neomycin ointment served for sealing the wound surface, no further dressing being used. After 215 cranial neurosurgical operations, among them 63 for tumours, 33 stereotactic procedures 18 shunt, 55 for torticollis and 46 other operations performed without shaving the hair, we saw one wound infection (0.5%). This percentage corresponds very well to our general infection rate of 0.6%. All patients very much appreciated the offered opportunity and the result. If the objective is to give patients a psychological advantage by preventing a partially bald head we think one can safely refrain from the shaving procedure without risking a higher infection rate.

Brain↗
PubMed2000

Functional cranial neuronavigation. Direct integration of fMRI and PET data.

OBJECTIVE: We report our first experiences with the direct integration of fMRI data into cranial neuronavigation. METHOD: For navigation we used the MKM system and thin-sliced T1 contrast enhanced images. As a first step 21 patients had fMRI for localization of the precentral gyrus, 2 patients for Broca area detection. By anatomical correlation, these functional data were indirectly compared to the intraoperative findings using cortical SSEP (n=20) or cortical stimulation (n=3). Encouraged by these preliminary results, we started the direct integration of fMRI into neuronavigation in June 1999, followed by PET in January 2000, enabling us to compare functional images with intraoperative findings directly. fMRI and PET data were integrated by landmark matching referring on skin fiducials. Meanwhile, fMRI data of 8 patients (6 motorcortex, 2 Broca) and PET images of 1 patient were directly integrated into neuronavigation. Six out of 8 patients had additional cortical monitoring, 2/8 were exclusively operated on by functional neuronavigation. RESULTS: Using indirect comparison between fMRI and intraoperative findings we observed a good correlation in every case for the motorcortex, but only in 1/2 for the speech area. In all 6 direct integrated fMRI cases, these findings corresponded well to the conventional ones. Both patients with sole functional navigation did not have any postoperative neurological deficit. The inaccuracy of the fMRI ifT1 matching was 2. 7 mm (sigma=0.9 mm) and 1.3 mm (sigma=0.4 mm) of the subsequent referenciation of the navigation. The tumor delinement shown by 11C-methionine PET could be proven by intraoperative biopsy outside its indicated tumor margin. The inaccuracy of the PET matching was 0. 8 mm. CONCLUSION: Functional neuronavigation enables to visualize and preserve relevant brain areas. Other functional areas like short-term memory, which solely can be detected by fMRI might also be monitored in the future. The integration of PET data expect to gain a better differentiation of tumor and edema.

Adult↗
PubMed1999

[Axillary nerve paralysis after playing squash. A case report].

A 27-year-old otherwise healthy male presented with an isolated but complete axillary nerve palsy after excessive squash playing. When repeated electromyographic investigations showed no signs of reinnervation in the deltoid muscle, surgery was performed in order to restore nerve function. Intraoperatively, the nerve showed a short segment of thinning about 2 cm distally the nerve's origin from the posterior fascicle. As intraoperative electrophysiological testing was also negative (no electrically evoked nerve action potentials across the lesion) the suspicious nerve segment was resected and nerve continuity restored by sural grafts. Histologically, no intact nerve structures could be found at the site of the thinning. Most likely the lesion was caused by traction forces. Follow-up studies showed reinnervation of deltoid function over time.

Adult↗
PubMed1999

[Metaplastic meningioma with cartilaginous differentiation].

A meningioma with cartilaginous areas is described. The tumour arose in the region of the right sphenoid wing in a 74-year-old woman. Histologically, it showed large areas of a typical meningothelial meningioma, among which numerous cartilaginous islands and some chondroid regions, obviously of intermediate (meningothelial/cartilaginous) differentiation, could be seen. Cartilaginous tumour areas showed lower MIB1-labelling indices than typical meningioma regions, where an increased proliferative activity was seen focally. The current WHO classification lists such tumours as metaplastic meningiomas, reflecting the potential of meningioma cells for mesenchymal differentiation. Metaplastic meningiomas may show different metaplasias (xanthomatous, osseous, lipomatous, cartilaginous, etc.). Extensive cartilaginous metaplasias are very uncommon. Identification of typical meningioma areas is the key for the diagnosis of this meningioma variant.

Aged↗
PubMed1998

[Lumbar spinal stenosis and its surgical treatment].

Today lumbar spinal stenosis can stand on its own as a clinical entity that can be radiologically and clinically divided into central and lateral stenosis. Foraminal stenosis is a special form of the latter. During the period 1990-1991 we operated on 148 patients for spinal stenosis. Using a standardized questionnaire, 109 patients were evaluated on their pain and gait status 3 years after the operation. Patients with previously known spondylolisthesis or degenerative instability were excluded from the study. Forty-four out of 109 patients were free of pain, while significant reduction of pain was noted in 35/109 patients. In 19 patients, the pain remained the same or worsened postoperatively. Seventy-four out of the 109 patients had no gait disturbances, whereas only 14/109 worsened postoperatively. Six patients could walk with support and seven patients were unable to walk because of other disturbances. Because of unclear responses, the status of the remaining patients could not be completely evaluated in either group.

Adult↗
PubMed1998

[Meningeal melanocytoma].

A 38-year-old man presented with an intracranial extra-axial tumour at the base of the left posterior fossa which proved to be a meningeal melanocytoma. Meningeal melanocytoma is a rare, benign melanotic tumour of the leptomeninges occurring predominantly in the posterior fossa or the upper spinal cord in adults. It shows characteristic cytologic features with isomorphic epitheliod or spindle-shaped cells, often with prominent nucleoli and a variable content of intracytoplasmic melanin. It usually lacks signs of malignancy such as high mitotic rate, necroses or infiltrative growth and shows a low labeling index in proliferation marker studies. Its immunohistological profile with S-100 protein-, vimentin- and HMB-45-positive tumour cells is similar to that of (primary or metastatic) malignant melanoma. This differential diagnosis is crucial because of the totally different therapeutic and prognostic implications. Therefore, everyone dealing with surgical neuropathology should be familiar with the rare, but clinically important diagnosis of meningeal melanocytoma.

Adult↗
PubMed1998

Laminar and arch fractures with dural tear and nerve root entrapment in patients operated upon for thoracic and lumbar spine injuries.

OBJECTIVE: To determine the neurological outcome in patients with laminar fractures associated with dural tears and nerve root entrapment, operated upon for thoracic and lumbar spine injuries. PATIENT POPULATION: Out of 103 patients operated upon consecutively for thoracic and lumbar spine injuries during the period 1990 to 1994 inclusive, 24 (23.3%) patients had laminar fractures out of whom 3 (2.9%) had an associated dural tear and an other 17 (16.5% or 70.8% of the total patients with laminar fractures) had an associated dural tear and nerve root entrapment. RESULTS: Twelve (70.5%) patients had injury at the thoraculumbar junction, 13 (76.5%) had Magerl's type A3 or above, 10 (58.8%) had a kyphotic angle deformity greater than 5 degrees. Seven (41.1%) had their spinal canal's sagittal diameter reduced by at least 50% and two had dislocations. Nine (52.9%) had initial neurological deficits. Four (50%) out of 8 patients with no initial neurological deficits (Frankel E) worsened to Frankel D. However, one patient among the 3 with initial Frankel A improved to Frankel C while both patients with initial Frankel C usefully improved to final Frankel grades D and E respectively. Two of the four patients with initial Frankel D improved to Frankel E, the other 2 remaining unchanged. All in all five patients neurological status improved, 4 worsened and 8 remained unchanged after neurosurgical treatment. CONCLUSIONS: Vertical laminar fractures with dural tears and nerve root entrapment represent a special group of thoracic and lumbar spine injuries that carry a poor prognosis. However, special operative precautions lead to significant improvement in some of them although a majority remain unchanged or even worsened.

Adult↗