A multifactorial conceptual model of peripheral neuromusculoskeletal predisposing factors in task-specific focal hand dystonia in musicians: etiologic and therapeutic implications.

A model is presented showing how peripheral factors may cause a process of movement adaptation that leads to task-specific focal hand dystonia in musicians (FHDM). To acquire a playing technique, the hand must find effective and physiologically sustainable movements within a complex set of functional demands and anatomic, ergonomic, and physiological constraints. In doing so, individually discriminating constraints may become effective, such as limited anatomic independence of finger muscles/tendons, limited joint ranges of motion, or (subclinical) neuromusculoskeletal defects. These factors may, depending on the instrument-specific playing requirements, compromise or exclude functional playing movements. The controller (i.e., the brain) then needs to develop alternative motions to execute the task, which is called compensation. We hypothesize that, if this compensation process does not converge to physiologically sustainable muscle activation patterns that satisfy all constraints, compensation could increase indefinitely under the pressure of practice. Dystonic symptoms would become manifest when overcompensation occurs, resulting in motor patterns that fail in proper task execution. The model presented in this paper only concerns the compensatory processes preceding such overcompensations and does not aim to explain the nature of the dystonic motions themselves. While the model considers normal learning processes in the development of compensations, neurological predispositions could facilitate developing overcompensations or further abnormal motor programs. The model predicts that if peripheral factors are involved, FHDM symptoms would be preceded by long-term gradual changes in playing movements, which could be validated by prospective studies. Furthermore, the model implies that treatment success might be enhanced by addressing the conflict between peripheral factors and playing tasks before decompensating/retraining the affected movements.

Differences in complexity of isolated brachydactyly type C cannot be attributed to locus heterogeneity alone.

Hereditary isolated brachydactyly type C (OMIM 113100) mostly follows an autosomal dominant pattern of inheritance with a marked variability in expression. This phenotype has been mapped to two different loci on chromosomes 12q24 and 20q11.2. The latter locus contains the cartilage-derived morphogenetic protein (CDMP)1 gene, in which a null mutation has been found in patients with malformations restricted to the upper limbs. A more complex brachydactyly type C phenotype has been mapped to chromosome 12q24. Differences in complexity of these phenotypes have been attributed to locus heterogeneity. Clinical subclassification based on the degree of complexity of the phenotype has therefore been suggested. We present patients with a complex brachydactyly type C phenotype in whom there is considerable intra- and interfamilial variability in expression. We show that clinical subclassification based on the complexity of the brachydactyly type C phenotype related to the genetic defect is not feasible. We present evidence that differences in complexity are not only due to locus heterogeneity, but that genetic modifiers and/or environmental factors must also play a role.

Is the pectoralis myocutaneous flap in intraoral and oropharyngeal reconstruction outdated?

METHODS: Our experience with 224 immediate pectoralis major myocutaneous flap reconstructions in patients with carcinomas of the oral and oropharyngeal cavities is presented. RESULTS: Although flap-related complications developed in 53% of the patients, all flaps survived, and we had no major skin paddle loss. The incidence of reoperation due to flap-related complications was 2%. All other complications were minor and did not affect the length of hospitalization. Analysis showed no significant risk factors for the development of complications. Because of fistula formation, infection, or metal exposure, plate removal was necessary in 10% of the AO fixation plates used in cases of mandibular swing. This occurred in 68% of the anterior and 22% of the lateral mandibular reconstructions performed with a reconstruction plate (P < 0.05). CONCLUSIONS: We conclude that a reconstruction plate is unsatisfactory for anterior mandibular continuity reconstruction and debatable for lateral mandibular reconstruction. At present, anterior defects are reconstructed with free vascularized osteocutaneous flaps that should probably also be used for lateral mandibular reconstruction. Furthermore, in a large number of series, it is reported that free flaps also have high complication rates and 5-10% flap loss. As all pectoralis major flaps survived in our series, it still remains a good choice in intraoral and oropharyngeal reconstruction when there is no necessity to reconstruct bone.

The hand of the musician: the kinematics of the bidigital finger system with anatomical restrictions.

Tendons of the fingers are frequently interconnected by anatomic structures that limit the displacements of these tendons relative to each other. In this paper a bidigital finger system in which such interconnections between tendons are present is kinematically modelled. Using this model, an exhaustive description of the effects on finger movement of connections between the different tendons of the fingers is given. The study provides a context for the interpretation of typical difficulties of finger coordination in musicians, especially in pianists and string players.

AV anastomosis as a solution for absent venous drainage in replantation surgery.

Three cases of replantation in which no conventional venous outflow could be established are presented. A method for obtaining venous outflow is described by using the contralateral artery as a venous pole and anastomosing it to a vein in the proximal stump (with or without a venous graft).

Surface-area increase in tissue expansion.

In this paper, the subject of surface-area gain in tissue expansion is approached from three sides. With the help of a mathematical approach, the theoretical increase in surface area was calculated in relation to the specifications of the expanders. In an in vitro model, these mathematical data were confirmed to be reliable. To determine the real surface-area gain that takes place in vivo, measurements on pigs were performed. It appears that only about 35 percent of the mathematically expected increase in surface area takes place. Moreover, a clear difference was observed between the surface-area gain for the different shapes of tissue expanders.

Recording congenital differences of the upper limb.

Consistent classification of congenital differences of the upper limb is of paramount importance for the study of the pathogenesis. To overcome the inconsistencies of present classifications, a non-classifying recording method has been developed. This method records individual aberrations, including bone and soft-tissue defects. Between 1996 and 1998, a prospective study was performed to validate the method. Two hundred and thirty-one patients with upper limb differences were assessed, and all individual aberrations were recorded. These data can be transferred to any classification. It is concluded that the presented method will allow consistent grouping of patients without losing details about simple and complex differences.

The use of the vastus lateralis musculocutaneous flap for the repair of trochanteric pressure sores.

The surgical technique of using the vastus lateralis as a musculocutaneous flap is described in 5 paraplegic patients. Good padding and closure are provided at the recipient site, and the donor site is closed primarily. This method enables use of other musculocutaneous flaps if required in the trochanteric area.

The free latissimus dorsi flap in reconstructive microsurgery.

The results are described of coverage of skin defects of the leg, foot and hand by use of a free vascularized musculocutaneous latissimus dorsi flap in 32 patients with previously incurable defects. Also presented are the case reports of three representative patients. The results show a success rate of 90%, with thrombosis of either the arterial or venous anastomoses as the only complications. Adequate postoperative screening (t.c. pO2, temperature, etc.) leads to early discovery of this thrombosis, after which revision can save the flap.

Treatment of fractures of the shaft of the humerus accompanied by paralysis of the radial nerve.

This paper reports the results of treatment of 17 patients with fractures of the shaft of the humerus accompanied by paralysis of the radial nerve in a series of 111 patients with fractures of the shaft of the humerus. In early operative explorations in 14 cases the radial nerve appeared undamaged in 13 cases. In cases where spontaneous recovery of the function of the radial nerve failed to occur, no evidence has been found that the delay in exploration influenced eventual motor recovery. The high incidence of undamaged nerves at exploration suggests that a conservative approach by collar and cuff or Sarmiento bracing is justified in such cases of fractures of the shaft of the humerus. Paralysis of the radial nerve associated with fractures of the shaft of the humerus is, in our opinion, not an indication for early operative treatment.

A technique to prevent aneurysm formation in microvascular anastomoses.

The occurrence of true aneurysm formation in microarterial anastomoses is well known. In up to 50% of microanastomoses this complication is found. In a microsurgical training group a new technique was taught, which did not give cause to any aneurysm formation at all. This technique allows only suturing with relative thin and many stitches, suturing of small edges of the vessel wall and short stripping of adventitia. Though operative skill perhaps is more demanding in this new technique, the merits are clear.

Morbidity in a microsurgical rat training model.

In a prospective study with 24 growing Wistar rats, with a mean body weight of 300 gram, microsurgery was trained. Patency as well as morbidity of the animals was assessed. There were 110 vascular anastomoses, constructed with various techniques. Of these, 104 were rendered for evaluation. The caliber of the vessels varied from 0.4 to 2.0 mm. On an average, the rats were operated two times, during which operations at least four anastomoses were created. Patency was related to caliber and flow rate of the vessel and varied between 50 and 100%. Mortality and weight increase, used to reflect morbidity were evaluated. Six animals died during or shortly after operation, three of them because of anaesthesia alone. Mean postoperative daily weight increase was 1 gram approximately. In the control group the weight increase was tripled. The rats needed two weeks after operation rats to regain their original weight. Analysis of results demonstrated highly significant difference between operated and non-operated rats. The study suggests, that morbidity of rats submitted to microsurgery will be reduced, if two weeks of recovery before other experiments are awaited. This may provide a standard for future experiments.

Pressure resistance of breast implants as a function of implantation time.

Using a relatively simple test, breaking pressures of 50 gel-filled breast implants that had to be removed have been evaluated. These pressures values were compared with forces generated in executing closed capsulotomy (nutcracker method). It is shown that there is a negative correlation between pressure resistance of breast implants and duration of implantation. After an implantation time of more than five years, our advice is to perform closed capsulotomy if done in a very gentle way, and implant rupture then certainly has to be taken into account.

Quantitative oxygen measurements before and after intravascular guanethidine blocks.

In 11 patients oxygen pressure was measured transcutaneously before and after treatment with regional intravascular sympathetic blocks in extremities with pain, impairment of function, and/or dystrophy. In 50 normal individuals PO2 levels were determined in the hand. All patients showed lower than normal values before treatment. Subjective complaints were registered by means of a questionnaire before and after treatment. Improvement of PO2 levels was observed after treatment in eight out of 11 patients while complaints disappeared. Three out of 11 patients showed no improvement of PO2 levels or any lessening of complaints. Control PO2 values in the contralateral limbs stayed on the same level as before treatment in all patients. From the results in this article it can be stated that TcPO2 measurements seem to be helpful in (1) evaluating the pretreatment microvascular state of the affected limb and (2) judging the efficacy of the block.

Clinical application of transcutaneous oxygen measurements in replantation surgery and free tissue transfer.

In 65 replantations and 18 free tissue transfers (6 toe-to-thumb and 12 free flaps) transcutaneous oxygen levels were used as a postoperative monitoring system of the microcirculation. In successful replants and successful free tissue transfers an identical pattern of oxygen levels was observed. In failing replants or free tissue transfer, PO2 levels react immediately to changes in microcirculation and these changes in PO2 appear several hours earlier than the clinical symptoms or changes in temperature. This enables salvage operations after circulatory failure caused by thrombosis to be performed before irreversible tissue damage occurs.

Connections between the tendons of the musculus flexor digitorum profundus involving the synovial sheaths in the carpal tunnel.

In the carpal tunnel anatomical interconnections between the tendons of the musculus flexor digitorum profundus are systematically present. These interconnections limit the mutual tendon displacements, which decreases finger independence and may be problematic in a musician's hand. The present study investigates a possible role of the synovial sheaths in the formation of these intertendinous connections in the carpal tunnel. To this end a morphological model is provided which correlates the often distinctly fibrous structure of the deep flexor tendons in the carpal tunnel and the frequent exchange of tendon fibres between the tendons to the different fingers, with the tendency of the synovial membranes to strongly adhere to the tendons. This model is validated by gross dissection results, and by cross sections of the flexor tendons in the carpal tunnel. In agreement with the model, the anatomic data show that the synovial membranes tend to invade and become trapped in tendons made up from individualised tendon strands, and also strongly adhere to the substantial amounts of tendon fibres which may be exchanged between the flexor tendons proximal to the lumbrical origins. These fibres and the synovial membranes may form a strong fabric able to withstand substantial stretching forces of interconnected oppositely pulled flexor tendons.