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Biomedical subjects

J Forst

Publications and source records attributed to J Forst.

25 records · Page 2Linked to original sources
PubMed1994

[Core decompression in Ahlbäck's disease. Follow-up and therapy control using MR tomography].

Clinically suspected spontaneous osteonecrosis of the knee (Ahlbäck's disease) was confirmed by MR imaging and subsequent histology in 4 male patients with sudden onset of severe knee pain. The first typical radiological sign for osteonecrosis--flattening of the affected femoral condyle--was seen in no case. All patients were treated surgically by extraarticular drilling for core decompression and were delivered from the complained severe knee pain immediately after surgery. The healing process of early osteonecrosis could be confirmed by the normalisation of bone marrow signal in MR imaging (3 to 15 months follow-up). Core decompression seems to be an effective treatment in early osteonecrosis of femoral condyles. MR imaging is the most sensitive method for early diagnosis of osteonecrosis and for preoperative planning as well as a helpful tool for a non-invasive postoperative follow-up.

Follow-Up Studies↗
PubMed1993

Effect of upper tibial osteotomy on fibula movement and ankle joint motion.

Several techniques of upper tibial osteotomy in the treatment of unicompartmental osteoarthritis of the knee have been described. Osteotomy of the fibula is normally also carried out, or alternatively, dissection of the capsule of the proximal tibiofibular joint. There is concern, however, that this latter procedure may have an adverse effect on the mobility of the ankle joint and on fibula rotation. To investigate these suspected interactions we performed experimental studies in 14 cadaver legs. The vertical, lateral and rotational movements of the fibula were measured with the ankle in neutral (0 degrees) and maximal ankle dorsiflexion before and after performing an interligamental upper tibial osteotomy of a standardised valgus wedge. Maximal ankle dorsiflexion before the osteotomy produced external rotation of the fibula in most specimens, whereas after osteotomy this movement caused mainly internal rotation. In the neutral position of the ankle, upper tibial osteotomy lead to external rotation of the fibula. The upward movement of the fibula head after osteotomy was 0.64 cm on average. There was no measurable vertical motion of the fibula during ankle dorsiflexion either before nor after upper tibial osteotomy. Ankle dorsiflexion improved minimally after osteotomy. In conclusion, this study shows that upper tibial osteotomy with dissection of the capsule of the proximal tibiofibular joint has no adverse effect on movement of the fibula or of the ankle joint. In addition, unlike fibular osteotomy, this technique also has the advantage that the risk of common peroneal nerve injury is minimal.

Ankle Joint↗
PubMed1993

Clinical application of a noninvasive multi-electrode array EMG for the recording of single motor unit activity.

Using a recently developed noninvasive EMG recording technique with multi-electrode arrays we investigated the pattern and distribution of motor unit action potentials (MUAP) following maximal voluntary contraction of the musculus abductor pollicis brevis. An additional parameter, i.e. muscular conduction velocity (CV) in single motor units, was calculated from the multi-electrode array EMG recordings. From 63 healthy children of various age the normal EMG pattern and CV were derived and compared to the EMG of diagnosed patients known to suffer from Duchenne muscular dystrophy and from spinal muscular atrophy. In normal individuals the muscular CV in neonates was lowest at 1-2 m/s and gradually reached a plateau of 2.9-4 m/s from the age of 4 years onwards. The EMG in 31 children with Duchenne muscular dystrophy showed an abnormal pattern with low amplitude action potentials. In 30 out of 31 patients a significantly lower muscular CV was found. In 10 children with spinal muscular atrophy the EMG showed action potentials of abnormally large amplitude and a reduced recruitment of firing motor units. The muscular CV remained within the normal range. Compared to classical needle EMG the application of this new noninvasive EMG technique in children is painless and offers an easy-to-handle diagnostic tool to differentiate between neuromuscular diseases of denervating or of myopathic origin.

Adolescent↗
PubMedDate not supplied

[Duchenne muscular dystrophy--contracture preventive operations of the lower extremities with special reference to anesthesiologic aspects].

So far there is no causal treatment for Duchenne muscular dystrophy up to now, it has been proven, however, that its course can be considerably improved by an early contracture-prophylactic operation of both lower limbs--mostly between age 4 and 6 years--as well as by a surgical stabilization of the spine before any progressive scoliosis appears, that is at the very beginning of the wheel-chair stage: Walking and standing ability can be prolonged for several years and a significant scoliosis can be avoided. A decisive prolongation of life can be achieved by treating the fatal respiratory insufficiency with timely started mechanical ventilation. Our first experiences have shown, that there is no proven justification for a reserved attitude against early lower limb surgery in view of modern anaesthesia. Malignant hyperthermia-reaction and hyperkalaemia are the known anaesthetic rise factors of operations in Duchenne muscular dystrophy. However, we could exclude virtually these rises by choosing the right anaesthesia and by a comprehensive monitoring routine. If need be, malignant hyperthermia can be treated effectively by using the obligatory antidote (Dantrolene). In view of an expected causal treatment in future, early detection of Duchenne muscular dystrophy by newborn screening ("CK-Test") as well as a comprehensive stage-depending treatment programme (early surgery/mechanical ventilation) are nowadays of outstanding importance.

Anesthesia, General↗
PubMedDate not supplied

[Characteristics in the treatment of scoliosis in muscular diseases].

INTRODUCTION: Patients suffering from the most frequent muscle disorders Duchenne muscular dystrophy (DMD) and spinal muscular atrophies (SMA), who ceased walking respectively are confined from the outset to the wheel-chair, are developing commonly a progressive scoliosis (collapsing spine) due to an increasing muscle weakness. Basing on the pelvic obliquity these scolioses are leading first of all to problems in sitting as well as difficulties in trunk and head control. Along with the increasing weakness of respiratory muscles these phenomena entail a restrictive respiratory insufficiency. CONSERVATIVE TREATMENT: An effective conservative treatment is not available for these scolioses. The use of a corset, however, can only be taken into consideration as a compromise, either for very young patients or those who refused an operation respectively who have reached an inoperable stage. The exclusive use of so-called "anatomic sitting supports" in the wheel-chair in order to treat or prevent a progressive scoliosis in DMD or SMA is absolutely to be rejected. They should only be applied for very young patients with SMA type II as a transitional solution until a corset or better an surgical stabilisation of the spine will be effected, or as a palliative measure in late stages. SURGICAL TREATMENT: Only the early as possible performed surgical stabilisation of the spine using adequate instrumentation (Luque, CD or modifications), enabling an early mobilization without corset or cast, is the most effective treatment of these scoliosis. Patients with DMD or SMA type III should be stabilized after loss of walking ability and definitive confinement to wheel-chair, if the curve is more than 20 degrees-30 degrees Cobb and progressive and forced vital capacity (FVC) is > 35%. The instrumentation should be applied between D3 or D4 and sacrum. The bony fusion mass should include the lumbar and lumbosacral region. The unfused instrumentation with the telescope-rod after Naumann is a good solution for patients with SMA type II and progressive curves already in the early childhood from ca. 5 years of age. First of all surgical spinal stabilisation improves the sitting comfort. Over and above this the improved cosmetic appearance should not be underestimated for the psychological condition of these patients. Additionally it is proved, that surgical stabilisation of the spine prolongs the life expectancy of patients with DMD. Furthermore stabilization of lung function can be achieved for both DMD and SMA patients in comparison to the natural history of these diseases. Altogether a decisive improvement of quality of life can be reached for all these patients.

Adolescent↗
PubMedDate not supplied

[Multi-segmental fusion of scoliosis in Duchenne's muscular dystrophy].

Operations in scoliosis in patients suffering from an advanced stage of Duchenne muscular dystrophy are associated with a higher risk due to the extent of the curves, the respiratory insufficiency and frequent cardiomyopathia. Progressive scolioses in 20 wheelchair patients with an age between 10.5-18.3 years (mean 14.6 years) were treated by CDI. The mean preoperative angle in this group was 70.6 degrees, the postoperative angle 31.2 degrees (mean correction 39.4 degrees or 55.8%). The preoperative lordosis of the lumbar spine (mean angle 4.1 degrees) was corrected to 17.8 degrees postoperatively. The average intraoperative blood loss (2300 ccm) was evident more compared with idiopathic scoliosis. One neurologic complication (postoperative disturbance of bladder function) was observed. Nowadays early surgical correction and stabilization (Cobb angle > 20 degrees) has to be recommended as the treatment of choice for scolioses in Duchenne muscular dystrophy using multisegmental instrumentation methods to enable rapid mobilisation and a postoperative care without brace or cast. This conception allows a prophylactic operation including the following targets: prolongation of life expectancy, improvement of sitting position and prevention of rapid deterioration of lung function including assisted mechanical ventilation in late stages.

Adolescent↗