Biomedical subjects

V Rohde

Publications and source records attributed to V Rohde.

At least 73 records · Page 4Linked to original sources

PubMed1999

[Motor evoked potentials during embolization of arteriovenous malformations for the detection of ischemic complications].

Motor evoked potentials (MEP) recorded from the distal extremity muscles in response to transcranial magnetoelectrical stimulation were analyzed in a total of 10 patients during embolization of arteriovenous malformations (AVM) localized in frontal and parietal lobe (N = 5), in the temporal lobe (N = 2), in the the brain stem (N = 1), in the medulla oblongata (N = 1), and in the cerebellum (N = 1). The objective of this study was to clarify whether MEP allow reliable detection of ischemic complications during these procedures. Stable potentials as observed in 8 of 10 patients coincided in every case with an uneventful neurological outcome. Temporary significant prolongation of the central motor conduction time (CMCT) was observed in 2 patients. Both patients demonstrated a transient hemiparesis after the procedure, probably caused by ischemia. Our results clearly indicate that MEP are able to detect ischemic events during embolization of AVMs. Therefore, the use of MEP as a monitor of pyramidal function during endovascular therapeutic procedures seems to be promising.

Adolescent↗

PubMed1998

Spondylodiscitis after lumbar discectomy. Incidence and a proposal for prophylaxis.

STUDY DESIGN: An analysis of the incidence of spondylodiscitis after lumbar disc surgery in 1642 patients. In 508 patients no prophylactic antibiotics were given. In 1134 patients a collagenous sponge containing gentamicin was placed in the cleared disc space. OBJECTIVES: To report the incidence of postoperative spondylodiscitis in cases in which no antibiotic prophylaxis was used, and to define the value of a collagenous sponge containing gentamicin in preventing disc space infections. SUMMARY OF BACKGROUND DATA: Spondylodiscitis is considered to be a rare complication of lumbar disc surgery. The retrospective design of most studies and the rare use of magnetic resonance imaging for early radiologic diagnosis suggest that the reported incidence rates may be underestimates. Postoperative spondylodiscitis is the result of intraoperative contamination and, theoretically, could be prevented by treating these patients with prophylactic antibiotics. METHODS: In 1642 patients, 1712 discectomies were performed. In 508 of these patients no prophylactic antibiotics were given; in 1134 of these patients a collagenous sponge containing gentamicin was placed in the cleared disc space. Clinical reexamination and, in cases of unsatisfactory results, laboratory and radiologic investigations were performed 4-8 weeks after surgery. RESULTS: In nineteen of the 508 patients who were not treated with antibiotic prophylaxis (3.7%) a postoperative spondylodiscitis developed, whereas none of the 1134 patients who received antibiotic prophylaxis became symptomatic (P < 0.00001). CONCLUSION: In the current study, a 3.7% incidence of postoperative spondylodiscitis was found in the absence of prophylactic antibiotics. Gentamicin-containing collagenous sponges placed in the cleared disc space were effective in preventing postoperative spondylodiscitis.

Administration, Topical↗

PubMed1998

Intraoperative localization of functional regions in the sensorimotor cortex by neuronavigation and cortical mapping.

Surgery of lesions within the central region requires exact intraoperative anatomical orientation and knowledge of the position of functional cortical regions to minimize the surgical trauma and to avoid postoperative neurological deficits. We combined somatosensory evoked potential (SSEP) phase reversal and/or cortical electrical stimulation with neuronavigation in 26 patients for localization and visualization of functional cortical areas and their anatomical site in relation to the lesion. After location of the central sulcus by means of SSEP phase reversal, the precentral gyrus was electrically stimulated to detect functional motor regions. Electrode position was documented, and the functional regions were related to the site of the lesion using a specially developed neuronavigation system. In 11 of 15 patients the central fissure was located with SSEP phase reversal. Electrical stimulation yielded motor evoked potentials in 23 of the total 26 patients. The anatomical site of these functional regions and their relation to the lesion were evaluated with the neuronavigation system. The precentral gyrus, central sulcus, and postcentral gyrus could be identified in all 23 cases. The combination of intraoperative electrophysiological mapping and neuronavigation provides safe and reliable localization of the sensorimotor cortex. This technique is a promising tool to minimize the risk of surgically caused sensory and motor deficits.

Adult↗

PubMed1998

[Telomerase in tumors: facts and perspectives].

Recent reports have indicated the ribonucleoprotein enzyme telomerase to play an important role in tumorigenesis. Activation of this enzyme is known to prevent progressive shortening of the end of the chromosomes, or telomeres, and hence to be critical in maintaining chromosomal integrity. The telomerase expressing cells require immortality. Supported by recent findings which suggest that telomerase activity is expressed in virtually all cancers but not in normal tissues, except those of the germline, hope grew up toward a potentially important new therapeutic target in the fight against cancer. An emerging hypothesis is that the inactivation of telomerase results in the death of immortal cells. If telomerase activation represents a tumor-specific feature, (gene) therapeutic applications would become most promising in regard to an effective anticancer therapy, possibly with limited side-effects. However, most recent studies report on telomerase activity to be also expressed in normal, non-neoplastic tissues as well as in non-neoplastic hyperproliferative lesions. The questions whether telomerase activity is tumor-specific or associated with (physiologic or pathologic) hyperproliferation is intriguing and remains to be clarified.

Cell Division↗

PubMed1998

Four-year experience with the routine use of the programmable Hakim valve in the management of children with hydrocephalus.

OBJECTIVE: Cerebrospinal fluid (CSF) over- and underdrainage symptoms are frequent sequelae of shunt placement in patients with hydrocephalus, sometimes requiring repeated operations. To achieve more adequate CSF drainage, the non-invasively programmable Hakim valve has been developed. Because the clinical experiences with this valve so far are confined to adults, we describe our experiences with the routine use of the programmable Hakim valve in childhood hydrocephalus. METHOD: Sixty children (mean age of 3.4 years) with hydrocephalus of various aetiologies have been shunted with the programmable Hakim valve. In the majority of cases, initial opening pressures of between 100 and 120 mm H2O were selected. The mean follow-up period was 2.1 years. RESULTS: Thirty-three readjustment of the pressure setting of the valve were performed in 20 children because of CSF overdrainage (low intracranial pressure syndrome n = 13, slit ventricle syndrome n = 2, hygroma n = 1), CSF underdrainage (n = 3) and CSF leakage through the operation wound (n = 1). The symptoms of inadequate CSF drainage were cured in 18 of the 20 children. The necessity for valve readjustments was independent of the aetiology of the hydrocephalus. Thirty-one complications requiring repeated operation occurred during the follow-up period, accounting for an annual complication rate of 24.6%. Three complications were valve-related. CONCLUSION: In the majority of cases, the programmable Hakim valve allows the successful management of symptoms related to CSF over- and underdrainage by non-invasive change of the initial pressure setting of the valve. Therefore, the programmable Hakim valve should be considered as an alternative to non-programmable valves of advanced design.

Adolescent↗

PubMed1998

Experience with a new multifunctional articulated instrument holder in minimally invasive navigated neurosurgery.

A new multifunctional articulated instrument holder for use in minimally invasive navigated neurosurgery is presented. The instrument holder is secured to the Mayfield clamp, yielding permanent fixation and guidance of instruments. Thus, surgical conditions with the advantages of both conventional and frameless stereotaxic neurosurgery are created without sacrificing the relevant advantages of both methods. Accuracy testing of the instrument holder in combination with the neuronavigation system EasyGuide Neuro demonstrated an error of 0.0 to 2.4 (mean 1.6) mm. In clinical testing, the device has been used for guided catheter insertions, pointer fixation for continuous intraoperative guidance and trajectory planning, navigated endoscopic procedures, and navigated intracerebral biopsies in totally 53 patients.

Equipment Design↗

PubMed1998

The combined use of image-guided frameless stereotaxy and neuroendoscopy for the surgical management of occlusive hydrocephalus and intracranial cysts.

The objective of the study was to report the initial experiences with the combined use of an infrared-based frameless stereotactic navigation device and neuroendoscopy. Ten hydrocephalic patients underwent endoscopic third ventriculostomy and two patients with intracranial cysts underwent cystoventriculostomy. The trajectory of the rigid endoscope and target point were planned by frameless stereotaxy. An articulated arm served to maintain the predetermined trajectory during the surgery and to guide the endoscope. Endoscopic surgery was successfully performed in 11 of the 12 patients. In one patient with a small third ventricle the ventriculostomy had to be abandoned. We observed no surgical morbidity. In none of the cases was it necessary to correct the predetermined trajectory of the endoscope to reach the planned target area. The planning of the trajectory and the target area, as well as the maintenance of the trajectory during endoscopy reduce the risk of inadvertent damage to vital structures. The combined use of frameless stereotaxy and neuroendoscopy might contribute to a decrease of procedure-related morbidity.

Adolescent↗

PubMed1998

Androgen receptor expression, proliferation index and aneuploidy in tissue explant cultures derived prostate carcinoma cells co-cultivated on membranes.

OBJECTIVES: An improved explant cell culture technique to avoid selection of prostatic adenocarcinoma cells toward diploid cells is described. MATERIAL AND METHODS: 21 prostatic carcinoma specimens which were obtained from 13 primary prostatic adenocarcinomas after radical prostatectomy were cultivated. Ploidy of the cells was monitored by fluorescence in situ DNA hybridization using the centromere-specific DNA probes pUC1.77, p alpha 7t1 and pY3.4. Phenotypic examination of androgen receptor (AR) expression was performed simultaneously with immunostaining by Ki-67 as proliferation marker to identify androgen-independent growing cell clones. RESULTS: Interestingly, a high aneuploidy rate of the cell cultures was found with maintenance of aneuploidy in 18 (86%) of the 21 paraffin-embedded cancer tissue specimens with proved aneuploidy. Significant aneuploid cell populations were retained up to a maximum of ten transfer steps. During serial transfer of tumor pieces the aneusomic fraction slightly decreased as well as the percentage of AR/Ki-67-positive cells. CONCLUSIONS: The presented in vitro model allows to study the proliferation of genetically abnormal cells with respect to hormone dependency in a paracrine situation.

Adenocarcinoma↗

PubMed1998

Long-term results following transurethral resection of the prostate.

Two subsets of a single-center study population with benign prostatic hyperplasia (n(1) = 232; n(2) = 214) undergoing transurethral resection (TUR) of the prostate (TURP 1979 and 1995) entered a retrospective study designed to examine the long-term follow-up. The actual data were assessed with a patient-addressed questionnaire. Preoperative voiding patterns did not differ significantly; postoperative micturition revealed comparable results for both groups. Mortality and TUR syndrome rates were reduced to very low levels. The most significant improvement was found in blood transfusions. The postoperative incidence of urethral stricture (1.7 vs. 1.5%) or bladder neck contracture (2.7 vs. 2.4%) were low and did not alter significantly. Urinary incontinence changed for both collectives (11.4 vs. 3.3%). Urodynamic investigations revealed that all (n = 21) but 1 of the patients with TURP 1979 had the incontinence due to different bladder dysfunctions, but not because of postoperative stress incontinence. The questionnaire about the patient's actual contentment after TURP 1979 showed 79% of the patients still satisfied, 12% neutral and 9% dissatisfied with their micturition. Overall the patients reported a generally favorable view of TURP outcome in the long-term follow-up.

Aged↗

PubMed1998

Microsatellite instability in sporadic carcinomas of the proximal colon: association with diploid DNA content, negative protein expression of p53, and distinct histomorphologic features.

BACKGROUND: Microsatellite instability (MIN) seems to characterize a particular subset of sporadic colorectal adenocarcinomas with the studies indicating a better clinical outcome for patients with MIN-positive tumors than for those with MIN-negative ones. The goal of this study was to further clarify whether a genotype-specific histomorphology of the right-sided colonic carcinomas can be identified. METHODS: MIN status, DNA content, and p53 protein expression were evaluated in cryoconserved specimens from 20 adenocarcinomas of the proximal colon and correlated to stage, grade, and other histomorphologic features. The study was restricted to tumors of the proximal colon because approximately 90% of all MIN-positive tumors were found in the proximal colon, and differences between right- and left-sided tumors cannot be excluded a priori. RESULTS: By using four microsatellite markers, instability was detected in 35% of the tumors analyzed. The clinicopathologic features in the MIN-positive tumors were found to differ markedly from the MIN-negative tumors in their poorly differentiated histologic pattern, extracellular mucin production, and favorable lymph node and distant metastatic behavior. A marked association was found between MIN positivity and DNA diploid status, as well as negative p53 immunostaining. CONCLUSIONS: The MIN-positive colonic carcinomas were characterized by distinct histomorphologic features that are recognizable at routine diagnostic evaluation. Poorly differentiated adenocarcinomas of the proximal colon, with only a few lymph nodes and no distant metastases at presentation, and lack of p53 accumulation are highly suggestive of being MIN positive. These tumors should be discriminated from the other poorly differentiated carcinomas, because they seem to be associated with an improved prognosis compared with the tumors without microsatellite instability.

Adenocarcinoma↗

PubMed1998

Genetic changes and telomerase activity in human renal cell carcinoma.

Using the sensitive telomeric repeat amplification protocol assay, we detected telomerase activity in 26 of 35 (74.3%) renal cell carcinomas analyzed. Subdivision of the tumors according to telomerase activity did not reveal an obvious association between the presence of telomerase activity and histomorphological stage, grade, tumor size, or DNA ploidy. Furthermore, no association was found between telomerase activity and a distinct chromosomal aberration pattern; namely, loss of genetic material on the short arm of chromosome 3. Telomerase activity was also detected in 6 of 35 (17.1%) normal corresponding renal tissue samples, which seems interesting in light of the supposed biological role of telomerase expression in carcinogenesis. Interestingly, telomerase activity was detected in three of the four (75%) kidneys bearing non-clear cell tumor types, whereas of the 31 kidneys with clear cell carcinomas, telomerase activity was found in only 3 (9.7%) normal tissue samples. In addition, the two renal angiomyolipomas and one of the two analyzed transitional cell carcinomas of the renal pelvis were telomerase negative.

Adult↗

PubMed1997

[Forum: Clips and coils in aneurysm treatment].

The treatment of cerebral aneurysms aims at the complete elimination of the aneurysm from the circulation. In the case of subarachnoid hemorrhage (SAH), early management prevents rebleeding and in incidental aneurysms, future rupture is to be prevented. Standardization of surgical techniques and optimized collateral measures have reduced the morbidity and mortality of early operations in SAH to 10% and 15%, respectively, in most series. As an alternative, endovascular techniques are being developed which attempt to obliterate the aneurysmal sack by packing it with detachable platinum-coils. A major difference between clipping and coiling is the closure of the aperture by the surgical clip which approximates the vessel walls. During coil embolization, that aperture stays open, allowing in some cases further compaction of the coils in subsequent months and years. Recanalization attributable to compaction depends on the size of the aneurysm and may necessitate repacking in up to 40% of the cases (aneurysms > 25 mm). As for the risk of rebleeding, a recanalized aneurysm is comparable to a partially clipped aneurysm. As the surgical results from early and delayed operations were obtained in randomized controlled studies, such randomized comparative studies will need to be applied to assess the value and risks and long-term results of endovascular strategies.

Aneurysm, Ruptured↗

PubMed1997

Randomized clinical trial of conventional cholecystectomy versus minicholecystectomy.

BACKGROUND: The main argument for laparoscopic cholecystectomy in preference to open cholecystectomy appears to be based on less traumatic incisions inflicted on the abdominal wall. To investigate the effects of different incision lengths on patients following elective open cholecystectomy, a randomized clinical study was conducted. METHODS: In this study 130 patients were randomly assigned to undergo either open cholecystectomy through a transverse subcostal incision of mean length 5.8 cm, so called minicholecystectomy (65 patients), or to undergo conventional cholecystectomy through a paracostal incision of mean length 13.1 cm (65 patients). The perception of pain after operation was measured by a visual analogue scale. To register late complications the mean(s.d.) hospitalization period after operation was extended to 11.5(1.2) days in the minicholecystectomy group and 15.4(2.5) days in the conventional cholecystectomy group. RESULTS: The perceived pain and analgesic requirements were found to be similar in both groups. Twelve of 65 patients in the minicholecystectomy group and four of 65 in the conventional cholecystectomy group developed wound haematoma. CONCLUSION: On the basis of this prospective randomized study, the hypothesis that a smaller incision length on the abdominal wall could lower the level of perceived pain, and therefore decrease the postoperative analgesic intake after minicholecystectomy, could not be confirmed.

Adult↗

PubMed1996

Cerebral vasospasm after subarachnoid haemorrhage of unknown aetiology: a clinical and transcranial Doppler study.

Sixteen patients (6 women, 10 men; mean age: 52.5 years) suffering from spontaneous subarachnoid haemorrhage (SAH) of unknown origin underwent a protocol of initial and then weekly computed tomography (CT), initial four-vessel digital subtraction angiography (DSA) and at least one control pancerebral DSA. Fourteen patients had magnetic resonance imaging before undergoing first control DSA. All patients had calcium-antagonists (Nimodipine) via a central venous catheter, were kept on the neurosurgical intensive care unit and followed daily with transcranial Doppler ultrasonography (TCD). One patient (6.3%) developed moderate and 5 (31.1%) developed severe cerebral vasospasm as documented with TCD and exhibited deterioration of their level of consciousness. These 6 patients were treated with induced hypertension, hypervolaemia and haemodilution. Their blood flow velocities were elevated for a mean of 8 (5-17) days with a peak after 12.5 (9-17) days following SAH. No complications due to treatment were noted. One patient of the non-vasospastic group died of pulmonary embolism, another patient had an ischaemic incident during angiography, which has led to permanent disability. On follow-up 2-24 months after SAH 14 patients had returned to their premorbid state. It is concluded that patients suffering from SAH of unknown origin should undergo repeated angiographic investigation and subsequent daily monitoring of their neurologic status including daily TCD recordings so that haemodynamic treatment can be established in the event of cerebral vasospasm, which may occur in up to one third of these patients.

Adult↗

PubMed1995

The combined pterional and orbitocygomatic approach to extensive tumours of the lateral and latero-basal orbit and orbital apex.

Using standardized transcranial (pterional, subfrontal, fronto-orbital) approaches, complete removal of tumours located in the latero-basal aspect of the orbit and the lateral orbital apex with or without extension to the temporal fossa is not possible or can only be achieved if excessive traction is applied to the contents of the orbit and the brain. In contrast, the combined pterional and orbitocygomatic approach provides unhindered access to the superior, lateral and latero-basal orbit, superior and inferior orbital fissure and, if required, to the temporal fossa including the foramina ovale and rotundum. Six patients with extensive orbital lesions underwent surgery using this technique with good operative results.

Adult↗

PubMed1995

The C-reactive protein for detection of early infections after lumbar microdiscectomy.

The tendency for short hospitalization after lumbar microdiscectomy implies the need for early confirmation or disapproval of serious postoperative infections such as spondylodiscitis or deep wound infections. The C-reactive protein (CRP) is a well-known screening parameter for monitoring postoperative infectious complications in other fields. Our objective was to establish the diagnostic significance of CRP-in comparison with ESR and WBC-for monitoring infectious complications after lumbar microdiscectomy. Over a 15 months period we studied prospectively a homogeneous group of N = 400 patients with lumbar disc herniations who were operated on a single level for the first time. CRP, ESR and WBC values were determined in all patients pre-operatively, and on postoperative days 1 and 5. Clinical and laboratory findings were correlated and the diagnostic significance of CRP, ESR and WBC calculated. N = 385 (96%) patients had an uneventful postoperative course. N = 15 (4%) patients developed infectious complications, of which N = 6 (1.5%) were unrelated and N = 9 (2.5%) related to surgery. Evaluation of the laboratory values showed: The CRP baseline is a very individual value of no prognostic relevance. A high postaggression peak is typical and essential as a reference value for only the future time course will disclose any infection. We found 0% false negative and 4% false positive results on day 5. The sensitivity for serial CRP testing was calculated as 100% and specificity as 95.8%. ESR (sensitivity: 78.1%/specificity: 38.1%) and WBC (sensitivity: 21.4%/specificity: 76.8%) both failed to reach such distinct diagnostic significance on day 5. The C-reactive protein has thus proved to be a reliable, simple and economical screening test for infectious complications after lumbar microdiscectomy, superior to classical laboratory parameters.

Adolescent↗

PubMed1995

Amount of subarachnoid blood and vasospasm: current aspects. A transcranial Doppler study.

Subsequent to admission after aneurysmal subarachnoid haemorrhage (SAH), 120 patients (74 women and 46 men) underwent microsurgical clipping of a total of 158 cerebral aneurysms within 96 hours after the bleed. Their mean age was 46 (20-91) years. Computed tomography (CT) findings were graded according to the modified Fisher scale and all patients had daily transcranial doppler (TCD) recordings of their basal cerebral arteries. In 19% of SAH was grade I on CT, in 44% grade II and in 37% grade III. The rate of patients who developed severe vasospasm as documented by TCD (mean blood flow velocities exceeding 160 cm/s on 2 or more consecutive days) was 39% for grade I patients, 26% for grade II patients and 34% for patients with SAH grade III on the initial CT. There was no difference in the rate of occurrence of severe vasospasm, when the patients were split into 2 groups according to the time of performance of the initial CT scan-within 24 hours, and 48-80 hours after SAH, respectively. It is concluded that the amount of subarachnoid blood on the initial CT scan should no longer be used as the indicator for occurrence and severity of the multifactorial entity vasospasm.

Adult↗

PubMed1995

Intraventricular recombinant tissue plasminogen activator for lysis of intraventricular haemorrhage.

A prospective series of 20 patients with moderate to severe intraventricular haemorrhage (IVH) was studied for the effect of intraventricular administration of recombinant tissue plasminogen activator (rt-PA) on reduction of haematoma volume and prognosis. On the day of haemorrhage ventriculostomy was performed and 2 to 5 mg of rt-PA were injected via the external ventricular drainage, followed by drainage closure for two hours. In 14 patients rt-PA treatment was repeated. Computed tomography showed complete clot lysis or substantial reduction of intraventricular haematoma volume in 19 patients within 96 hours; the clearance of the third and fourth ventricle preceded the clearance of the lateral ventricles. Decrease of ventricular enlargement was seen in all but one patient with initial ventricular dilatation. Increase of haematoma volume and ventricular size was found in one patient. Outcome was minor or no neurological deficit in nine patients, disabling neurological deficit in six patients, and vegetative status in four patients. One patient did not survive the IVH. Intraventricular treatment with rt-PA seems effective in rapid lysis of intraventricular haematoma and normalisation of impaired CSF circulation. This treatment may contribute to an improvement in prognosis of moderate to severe IVH.

Adult↗