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Biomedical subjects

R A Venbrocks

Publications and source records attributed to R A Venbrocks.

10 recordsLinked to original sources
PubMed2005

[The acquired buckling-flatfoot. A foot deformity due to obesity?].

Flatfoot deformity is characterized by a multiplanar hindfoot malalignment. Although the etiology remains unclear, the deformity is mainly attributed to ligamentous laxity and dysfunction of the posterior tibial tendon. Obesity is thought to be a risk factor that additionally impairs hindfoot stability. Performing a retrospective clinical and radiological study, we compared two groups, each with 75 patients. One group included patients with a flatfoot deformity stage 2, while the other group showed no hindfoot malalignment. Reviewing the weight and calculating the body mass index revealed significantly increased values for those patients with flatfoot deformity (P=0.034 and P>0.001, respectively). This correlation should be considered during the decision-making process on surgical strategies. In obese patients with flatfoot deformity, stage 2 soft tissue reconstruction and hindfoot osteotomies should be combined with hindfoot arthrodeses, i.e. subtalar fusion, to maintain sufficient and durable stability.

Adult↗
PubMed2005

[Metatarsalgia. Differential diagnosis and therapeutic algorithm].

Metatarsalgia is explained as localized or more diffuse tenderness beneath the metatarsal heads. The pain may be attributed to various etiologies. Pathological changes affecting the positional relationship of the metatarsals in the sagittal plane can cause increased pressure and friction forces during weight bearing. Since the length of the metatarsals displays a wide range of disparity only a few pathological settings, i.e., brachymetatarsia, require surgical correction. Beside those disorders of positional relationship, metatarsalgia may be due to lesser toe deformities, osteonecrosis of a lesser metatarsal head (Koehler's disease), and neurological disorders (Morton's neuroma). Apart from the etiology increased load, which is transferred to the central metatarsals, can be treated successfully with orthotic devices. If conservative measures fail, surgical treatment can be indicated. Prior to any operative therapy it is mandatory to perform a detailed analysis of the underlying pathology to avoid persistent pain or recurrence of the deformity.

Algorithms↗
PubMed2002

Effect of bupivacaine application on cholinesterase activities, total protein- and albumin concentration in serum and cerebrospinal fluid.

The rationale of this study was to determine whether Bupivacaine used for spinal anesthesia alters the specific secretory activity of nerve cells and/or the function of the blood/cerebrospinal fluid barrier. Four groups were assessed: (1) patients undergoing spinal anesthesia using Bupivacaine for lower limb surgery, (2) spinal Bupivacaine anesthesia without subsequent surgery, (3) local facet joint infiltration using Bupivacaine, and (4) general anesthesia for lower limb surgery without Bupivacaine application. Cholinesterase activities, total protein- and albumin concentrations in serum as well as in cerebrospinal fluid were significantly decreased after surgical intervention under spinal Bupivacaine anesthesia but remained unchanged following spinal Bupivacaine application without surgery. No significant correlation was found between Bupivacaine dosage and parameter alteration. There was no influence of intrathecal Bupivacaine application on the albumin ratio cerebrospinal fluid/serum, nor was there any significant alteration of total protein- or albumin concentrations and butyrylcholinesterase activity in the serum as a result of local injection of Bupivacaine to facet joints. These serum parameters were reduced after surgery under general anesthesia. Alterations of serum- and cerebrospinal fluid parameters investigated after surgery are not related to Bupivacaine application but to effects linked to operative treatment, i.e. suppressed secretory cell activity or protein depletion owing to blood loss. We conclude that the secretory function of cholinesterase-releasing nerve cells is not affected by spinal application of Bupivacaine. The blood/cerebrospinal fluid barrier remains intact.

Aged↗
PubMed2001

Acetylcholinesterase assay for cerebrospinal fluid using bupivacaine to inhibit butyrylcholinesterase.

BACKGROUND: Most test systems for acetylcholinesterase activity (E.C.3.1.1.7.) are using toxic inhibitors (BW284c51 and iso-OMPA) to distinguish the enzyme from butyrylcholinesterase (E.C.3.1.1.8.) which occurs simultaneously in the cerebrospinal fluid. Applying Ellman's colorimetric method, we were looking for a non-toxic inhibitor to restrain butyrylcholinesterase activity. Based on results of previous in vitro studies bupivacaine emerged to be a suitable inhibitor. RESULTS: Pharmacokinetic investigations with purified cholinesterases have shown maximum inhibition of butyrylcholinesterase activity and minimal interference with acetylcholinesterase activity at bupivacaine final concentrations between 0.1 and 0.5 mmol/l. Based on detailed analysis of pharmacokinetic data we developed three equations representing enzyme inhibition at bupivacaine concentrations of 0.1, 0.2 and 0.5 mmol/l. These equations allow us to calculate the acetylcholinesterase activity in solutions containing both cholinesterases utilizing the extinction differences measured spectrophotometrically in samples with and without bupivacaine. The accuracy of the bupivacaine-inhibition test could be confirmed by investigations on solutions of both purified cholinesterases and on samples of human cerebrospinal fluid. If butyrylcholinesterase activity has to be assessed simultaneously an independent test using butyrylthiocholine iodide as substrate (final concentration 5 mmol/l) has to be conducted. CONCLUSIONS: The bupivacaine-inhibition test is a reliable method using spectrophotometrical techniques to measure acetylcholinesterase activity in cerebrospinal fluid. It avoids the use of toxic inhibitors for differentiation of acetylcholinesterase from butyrylcholinesterase in fluids containing both enzymes. Our investigations suggest that bupivacaine concentrations of 0.1, 0.2 or 0.5 mmol/l can be applied with the same effect using 1 mmol/l acetylthiocholine iodide as substrate.

Acetylcholinesterase↗
PubMed2000

Salvage of the upper extremity in cases of tumorous destruction of the proximal humerus.

Malignant bone tumours or metastasis of the upper humerus may cause significant loss of function especially in those patients with resectional arthroplasty of the shoulder. One method for achieving functional reconstruction of the humerus concerned is replacement with a modular endoprosthesis. Little is known about clinical and radiological results in these rare circumstances. Between 1993 and 1997 we treated 21 patients (22 shoulders) with enlarged osteolytic destructions of the proximal humerus caused by metastatic spread or primary malignant tumours. Patients with additional involvement of the glenoid were excluded from this study. The average follow-up was 3.9 years. Every 3 months all patients were followed-up clinically and radiographically. Prior to surgery, diagnosis was established by incisional biopsy and the outcome determined the therapeutic algorithm (radiotherapy, chemotherapy, surgery). In most cases of metastatic lesions, surgery was the first treatment. According to the regional spread of the tumour, various amount of bone and soft tissues had to be removed. The distal stem of the prosthesis was inserted in a cementless way and secured to bone with two interlocking screws. The length of the diaphyseal part depended on the site of osteotomy. Soft-tissue coverage of the large implant was achieved in all patients. Early complications were lymphogenic oedema and superficial wound dehiscence. One patient developed a deep infection, which had to be managed surgically. According to the functional rating system of the Musculoskeletal Tumour Society for the upper extremity the overall results were inversely proportional to the extent of resection. None of our patients achieved unrestricted motion of the shoulder concerned. The most important finding was a proximal migration of the prosthesis causing a painful subacromial impingement, mainly a consequence of the resection of the deltoid muscle and the rotator cuff. In summary, a modular endoprosthesis cannot be recommended generally as the method of choice. If the muscular balance of the shoulder is too weak to act as a joint centralizer the endoprosthesis has no advantage over a simple diaphyseal spacer.

Adult↗
PubMed1999

[Complications and therapy after arthroscopic interventions of the knee joint].

Complications following arthroscopic knee surgery are known from the literature to be relatively rare. It hence is all the more important for the rehabilitation staff to know the possible risks for complications. Usually it is quite sufficient to perform a good clinical examination in case of complications in order to be able to carry out the necessary therapeutic measures in regular contact with the surgeons involved. Among the most dangerous complications requiring immediate therapy are the extraarticular vascular complication, the knee joint infection, and the intraarticular bleeding complication. Responsible teamwork among surgeons and rehabilitation staff will be the key to a successful treatment outcome.

Arthroscopy↗
PubMed1979

Renin activity and concentrations of angiotensin I and II in amniotic fluid of normal and Rh-sensitized pregnancies.

Renin activity and the concentrations of angiotensin I and angiotensin II in amniotic fluid of second- and third-trimester pregnancies were determined by radioimmunoassay. Between the 28th and 38th wk of gestation, the mean renin activity in the amniotic fluid was higher than during early pregnancy (before the 18th wk of gestation). Both renin activity and the concentrations of angiotensin I and II were increased on some cases of Rh-incompatibility. One to two weeks after the administration of betamethasone to the mother with threatened premature delivery, the intra-amniotic renin--angiotensin system was slightly suppressed. In urine samples of newborns, angiotensin concentrations were in the same range as those found in the amniotic fluid; renin activity was very low or undetectable in the urine of male neonates (1--7 days of age). Thus, angiotensin II in the amniotic fluid may be derived both from fetal urine and/or as the product of enzymatic reactions in the amniotic sac; the latter is dependent not only on the presence of renin and converting enzyme but also on the local renin substrate (angiotensinogen) concentration.

Adult↗
PubMedDate not supplied

[5-year follow-up study of total knee arthroplasty by means of EMG mapping].

AIM: The objective of the present study was to evaluate the long-term functional results after implantation of a total knee arthroplasty (TKA) objectively and quantitatively. METHOD: Functional parameters (muscular coordination, strength and range of motion) and the subjective satisfaction of the patients were measured by means of EMG mapping, isokinetics, ultrasound and a questionnaire in 21 patients with TKA 5.1 years after implantation of the TKA. RESULTS: 81 % of the investigated patients were subjectively satisfied. The isokinetic results showed a significant improvement of the extensor strength and of the relation between flexors and extensors. Patients who had been more physically active over these 5 years reached significantly better results. The results of EMG mapping showed good overall retention of the satisfactory coordination levels resulting from the initial in-patient rehabilitation. But the coordination patterns demonstrated clear changes showing highly activated areas in the region of the M. vastus medialis. The range of motion and the contraction capacity showed no further improvement compared with the results 26 weeks after implantation of the TKA. CONCLUSION: Long-term results after implantation of a TKA showed a good muscular coordination, strength and range of motion. A higher physical activity level led to better functional results and greater overall satisfaction of TKA patients 5 years after implantation.

Activities of Daily Living↗
PubMedDate not supplied

[The subacromial impingement syndrome].

The subacromial impingement syndrome describes the pathological contact between the rotatory cuff and the acromion. It is only a symptom and not a generic term for the different pathological diseases of the subacromial region. It is the diagnostical aim to verify the pathogenesis of the impingement syndromes and it is essential to differentiate structural versus functional causes. The diagnosis "impingement syndrome" should not have an acromioplastic procedure as general consequence. Because the expression "impingement syndrome" does not show causal approach it should no longer be used as a diagnosis. The term subacromial syndrome, in conjunction with the underlying pathological cause, acquires more therapeutic and prognostic clarity.

Diagnosis, Differential↗