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Biomedical subjects

J H Coert

Publications and source records attributed to J H Coert.

At least 19 recordsLinked to original sources

Comparison of assessment tools to score recovery of function after repair of traumatic lesions of the median nerve.

In this paper the recovery after repair of the median nerve has been used to compare different assessment tools for evaluation of peripheral nerve function: touch (moving 2-point discrimination (2PD); Semmes-Weinstein (SW) monofilament, motor (Medical Research Council (MRC) scale), combined motor and sensory (Dellon modification of the Moberg pick up test; Moberg Recognition test), and pain (visual analogue scale; pinprick-test). The mean (SD) age of our 28 patients was 28 (12) years. The mean (SD) follow-up period was 5 years, 2 months (2 years, 8 months). On the operated side three patients (11%) had a moving 2PD of less than 4 mm. The results of the moving 2PD were compared with those of the SW monofilaments, but with a poor correlation. The MRC score correlated well with opposition movement of the thumb and muscle wasting (p<0.01). We recommend a number of tests to evaluate (the chronological return of) peripheral nerve function.

Adult↗

Impairment and employment issues after nerve repair in the hand and forearm.

PURPOSE: To evaluate retrospectively subjective impairments, experienced disabilities, job and leisure restrictions and job changes in patients at least 2 years after repair of a peripheral nerve injury in the forearm, wrist or hand. METHODS: Between January 1,997 and January 2,000, 125 patients were treated surgically for a peripheral nerve injury in the hand and forearm at the Department of Plastic Surgery of a University Hospital. Sixty-one patients met the inclusion criteria. Using a questionnaire the ability to return to work (RTW), the possible consequences on Activities of Daily Life (ADL) and Instrumental Activities of Daily Life (IADL), job, hobby and housekeeping related disabilities and subjective pain were assessed. RESULTS: Forty of the 61 included patients returned the questionnaire. As a result of the injury, seven patients (19%) were not able to return to their own job and eight patients (20%) needed to quit or change their hobbies. Mean Time Off Work (TOW) was significantly longer (p=0.024) in non-digital nerve lesions (21.4 weeks) as compared to digital nerve lesions (9.5 weeks). CONCLUSIONS: From this study it was concluded that digital nerve lesions have little consequence on the ability to return to work and the time off work. However, the patients' hobbies are significantly affected. At least 2 years after the injury, the effects on ADL and IADL are minor.

Activities of Daily Living↗

Poor results after nerve grafting in the upper extremity: Quo vadis?

The clinical success of peripheral nerve grafting in the upper extremity was evaluated retrospectively in 41 patients. This study comprises a 10-year follow-up in a single institution. Donor and acceptor site morbidity as well as functional nerve recovery were evaluated. Thirty-one men and 10 women were included. Autologous nerve grafts were used for reconstruction of digital nerves in 17 patients, ulnar nerves in 12 patients, median nerves in 10 patients, radial nerve in 1 patient, and both the radial and median nerve in 1 patient. The length of nerve grafts ranged from 1-12.5 cm (mean, 4.8 cm). The follow-up period ranged from 18 months to 10 years. Acceptor site-related problems were noted in 51%% (n = 21) of patients. Donor-site morbidity was seen in 4 patients (10%%). The return of function was scored as "good" in 3 (7%%), "fair" in 11 (27%%), and "bad" in 27 (66%%) patients. The outcome of autologous nerve grafts in this small group of patients treated by several surgeons was unfavorable in terms of function. Recent experimental and clinical studies with biodegradable nerve guides for the repair of peripheral nerve gaps showed superior results in comparison to classic nerve grafts.

Adolescent↗

Cerebral reorganisation of human hand movement following dynamic immobilisation.

Surgical treatment of a flexor tendon lesion of the hand is followed by a 6-week period of dynamic immobilisation. This is achieved by the elastic strings of a Kleinert splint, enabling only passive and no active flexor movements. After such immobilisation, the appearance of a temporary clumsy hand indicates decreased efficiency of cerebral motor control. Using PET we identified the recruitment of contralateral parietal and cingulate activations specifically related to the suboptimal character of these hand movements. After 6-8 weeks, normalised movement was related with contralateral putamen activation. Activations of the sensorimotor cortex and cerebellum were present during both scanning sessions. Changes in the pattern of cerebral activations reflect functional reorganisation. The shift from cortical to striatal involvement, observed in the group of four patients, generates the concept of unlearned movements being relearned.

Cerebellum↗

Recovery of touch after median nerve lesion and subsequent repair.

Many techniques have been developed for the evaluation of peripheral nerve function. Consequently, physicians use different techniques in the clinic. This study describes the evaluation of touch after median nerve lesions in the forearm and repair. In order to evaluate touch, 25 patients, aged 11-51 years (mean, 29 years), were evaluated 3-10.5 years (mean, 5 years) after median nerve repair. The evaluation included the moving two-point discrimination test and Semmes-Weinstein monofilaments. We showed that 32% good-excellent results can be obtained with difficult nerve lesions. The results could have been improved if a sensory reeducation regime had been applied.

Adolescent↗

Quantifying thumb rotation during circumduction utilizing a video technique.

Thumb rotation is an essential component of circumduction in order to achieve pulp to pulp contact. In order to evaluate opponensplasty, a device was developed to quantify thumb rotation utilizing a special jig to hold the hand and video analysis. Twenty-seven healthy volunteers (12 female and 15 male) were tested to obtain normative data. Thumb rotation was measured as the difference in angle between the thumb in abduction and extension and maximal circumduction. Rotation angles varied from 70 degrees to 110 degrees. No gender or right/left differences could be detected. We concluded that comparing rotation of the non-injured hand to the injured hand in evaluating opponensplasties can be used as an accurate measurement of thumb circumduction and opposition.

Adult↗

Gliding resistance of extrasynovial and intrasynovial tendons through the A2 pulley.

The gliding ability of the flexor digitorum profundus tendon and of the palmaris longus tendon through the A2 pulley was compared, in terms of gliding resistance, with use of a system that we developed. Fourteen digits and the ipsilateral palmaris longus tendons from fourteen cadavera were used. The average gliding resistance at the interface between the palmaris longus tendon and the A2 pulley was found to be greater than that between the flexor digitorum profundus tendon and the A2 pulley under similar loading conditions. We concluded that the gliding ability of the palmaris longus tendon was inferior to that of the flexor digitorum profundus tendon in vitro.

Biomechanical Phenomena↗

Method for the measurement of friction between tendon and pulley.

An experimental system was developed that allows direct measurement of friction at the tendon-pulley interface, and the results were interpreted by use of a theoretical model for friction of a cable around a fixed pulley. Validation experiments were conducted with a nylon cable around a nylon rod. One end of the cable was connected to an actuator via a load cell, and the other end was connected to a 4.9 N load via a similar load cell. The cable was passed around the nylon rod and then pulled toward the actuator. Tests were performed at five different arcs of contact. The friction forces, as measured by the difference between two load transducers, were compared with those determined for a theoretical model and were used for calculation of the friction coefficient. The measurement system then was used to study the friction force between the flexor digitorum profundus tendon and the A2 pulley on nine fresh frozen index digits. The method allows us to measure the direct interaction between the tendon and pulley and could be used to evaluate and compare procedures for tendon-pulley and pulley repair and reconstruction, as well as for the study of tendon-pulley friction in various pathological conditions.

Fingers↗

Flexor tendon-pulley interaction after tendon repair. A biomechanical study.

Ten normal ring fingers from ten donors were used to determine the effect of flexor tendon repair on the gliding resistance between the tendon and the A2 pulley. Gliding resistance was measured for the intact FDP tendon and for the same tendon after it was cut transversely and repaired with a 4/0 Ticron core suture and a 6/0 running epitendinous nylon suture. After repair, the gliding pattern of the tendon through the A2 pulley changed significantly. The resistance and the friction coefficient were approximately doubled (P < 0.005).

Biomechanical Phenomena↗