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Martijn J A Malessy

Publications and source records attributed to Martijn J A Malessy.

7 recordsLinked to original sources
PubMed2006

Recovery of hand function following nerve grafting and transfer in obstetric brachial plexus lesions.

OBJECT: Infants with obstetric brachial plexus lesions (OBPLs) commonly undergo surgical repair. Outcome data have been documented extensively for shoulder and biceps function, but information on hand function following nerve repair is limited. Hand function is impaired in approximately 15% of patients. The authors present a surgical strategy aimed primarily at restoration of hand function and analyze their methods and outcome to determine specific factors affecting functional recovery. METHODS: Surgical strategy and outcome data were reviewed for 33 patients who underwent surgery for flail arm during a 10-year period. Nerve repair was performed at a mean age of 4.4 months. In 16 patients, the period of follow up (mean 50 months) was considered sufficiently long for final analysis. Of these 16 patients, 13 (Group 1) had complete discontinuity of the C-7, C-8, and T-1 spinal nerves. In three patients (Group 2), the C-8 and/or T-1 nerve was left in place because of shortage of nerve grafts or limited availability of proximal donor stumps. Postoperatively, a Raimondi hand function grade of 3 or higher was attained by nine of the 13 patients in Group 1 (69%) and one of the three patients in Group 2 (33%). CONCLUSIONS: Useful hand function was restored in 69% of the patients in the presented series in whom reanimation of the hand could be fully attributed to the surgical reconstruction. The authors conclude that restoration of hand function should be the first goal of nerve repair in infants with a flail arm caused by an OBPL, but that the optimal strategy for different types of lesion remains to be determined.

Birth Injuries↗
PubMed2005

External rotation as a result of suprascapular nerve neurotization in obstetric brachial plexus lesions.

OBJECTIVE: Obstetric brachial plexus lesions may cause lifelong limitations of upper limb function. Nerve repair is widely advocated in infants who do not show spontaneous recovery. Typically, the suprascapular nerve (SSN) is involved in the lesion. Neurotization of the SSN routinely is performed, aiming at reinnervation of the infraspinatus muscle to restore external rotation. The results after SSN neurotization have not, as yet, been studied in detail; therefore, this study was undertaken. Of special interest was the comparison of two commonly applied SSN neurotization procedures: nerve grafting from C5 versus nerve transfer of the accessory nerve. METHODS: Infants with obstetric brachial plexus lesions after nerve grafting of C5 to the SSN (n = 65) or nerve transfer of the accessory nerve to the SSN (n = 21) were selected for retrospective analysis after a mean follow-up period of 3 years. Outcome was expressed in degrees of true glenohumeral external rotation. This was defined as the angle between the position of the 90 degrees (actively or passively) flexed elbow resting against the abdomen and the position of the flexed elbow after external rotation with the upper arm held in adduction by the investigator. This movement can be executed only by infraspinatus muscle contraction. In addition, functional external rotation was evaluated by testing the ability to reach the mouth and the back of the head. RESULTS: Only 17 (20%) of the 86 patients reached more than 20 degrees of external rotation, whereas 35 (41%) were unable to perform true external rotation. There was no statistically significant difference between nerve grafting from C5 and extraplexal nerve transfer using the accessory nerve. Functional scores showed that 88% can reach the mouth and that 75% can reach the head. CONCLUSION: The restoration of a fair range of true glenohumeral external rotation after neurotization of the SSN in infants with obstetric brachial plexus lesions, whether by grafting from C5 or by nerve transfer of the accessory nerve, is disappointingly low. However, it seems that compensatory techniques contribute to effectuate a considerable range of movement.

Birth Injuries↗
PubMed2004

Electrophysiology and morphometry of the Aalpha- and Abeta-fiber populations in the normal and regenerating rat sciatic nerve.

We studied electrophysiological and morphological properties of the Aalpha- and Abeta-fibers in the regenerating sciatic nerve to establish whether these fiber types regenerate in numerical proportion and whether and how the electrophysiological properties of these fiber types are adjusted during regeneration. Compound action potentials were evoked from isolated sciatic nerves 12 weeks after autografting. Nerve fibers were gradually recruited either by increasing the stimulus voltage from subthreshold to supramaximal levels or by increasing the interval between two supramaximal stimuli to obtain the cumulative distribution of the extracellular firing thresholds and refractory periods, respectively. Thus, the mean conduction velocity (MCV), the maximal charge displaced during the compound action potential (Q(max)), the mean firing threshold (V(50)), and the mean refractory period (t(50)) were determined. The number of myelinated nerve fibers and their fiber diameter frequency distributions were determined in the peroneal nerve. Mathematical modeling applied to fiber recruitment and diameter distributions allowed discrimination of the Aalpha- and Abeta-fiber populations. In regenerating nerves, the number of Aalpha-fibers increased fourfold while the number of Abeta-fibers did not change. In regenerating Aalpha- and Abeta-fibers, the fiber diameter decreased and V(50) and t(50) increased. The regenerating Aalpha-fibers' contribution to Q(max) decreased considerably while that of the Abeta-fibers remained the same. Correlation of the electrophysiological data to the morphological data provided indications that the ion channel composition of both the Aalpha- and Abeta-fibers are altered during regeneration. This demonstrates that combining morphometric and electrophysiological analysis provides better insight in the changes that occur during regeneration.

Action Potentials↗
PubMed2004

Evaluation of suprascapular nerve neurotization after nerve graft or transfer in the treatment of brachial plexus traction lesions.

OBJECT: The aim of this retrospective study was to evaluate the restoration of shoulder function by means of suprascapular nerve neurotization in adult patients with proximal C-5 and C-6 lesions due to a severe brachial plexus traction injury. The primary goal of brachial plexus reconstructive surgery was to restore biceps muscle function and, secondarily, to reanimate shoulder function. METHODS: Suprascapular nerve neurotization was performed by grafting the C-5 nerve in 24 patients and by accessory or hypoglossal nerve transfer in 29 patients. Additional neurotization involving the axillary nerve was performed in 18 patients. Postoperative needle electromyography studies of the supraspinatus, infraspinatus, and deltoid muscles showed signs of reinnervation in most patients; however, active glenohumeral shoulder function recovery was poor. In nine (17%) of 53 patients supraspinatus muscle strength was Medical Research Council (MRC) Grade 3 or 4 and in four patients (8%) infraspinatus muscle power was MRC Grade 3 or 4. In 18 patients in whom deltoid muscle reinnervation was attempted, MRC Grade 3 or 4 function was demonstrated in two (11%). In the overall group, eight patients (15%) exhibited glenohumeral abduction with a mean of 44 +/- 17 degrees (standard deviation [SD]; median 45 degrees) and four patients (8%) exhibited glenohumeral exorotation with a mean of 48 +/- 24 degrees (SD; median 53 degrees). In only three patients (6%) were both functions regained. CONCLUSIONS: The reanimation of shoulder function in patients with proximal C-5 and C-6 brachial plexus traction injuries following suprascapular nerve neurotization is disappointingly low.

Adolescent↗
PubMed2003

Functional magnetic resonance imaging and control over the biceps muscle after intercostal-musculocutaneous nerve transfer.

OBJECT: Recent progress in the understanding of cerebral plastic changes that occur after an intercostal nerve (ICN)-musculocutaneous nerve (MCN) transfer motivated a study with functional magnetic resonance (fMR) imaging to map reorganization in the primary motor cortex. METHODS: Eleven patients with traumatic root avulsions of the brachial plexus were studied. Nine patients underwent ICN-MCN transfer to restore biceps function and two patients were studied prior to surgery. The biceps muscle recovered well in seven patients who had undergone surgery and remained paralytic in the other two patients. Maps of neural activity within the motor cortex were generated for both arms in each patient by using fMR imaging, and the active pixels were counted. The motor task consisted of biceps muscle contraction. Patients with a paralytic biceps were asked to contract this muscle virtually. The location and intensity of motor activation of the seven surgically treated arms that required good biceps muscle function were compared with those of the four arms with a paralytic biceps and with activity obtained in the contralateral hemisphere regulating the control arms. Activity could be induced in the seven surgically treated patients whose biceps muscles had regained function and was localized within the primary motor area. In contrast, activity could not be induced in the four patients whose biceps muscles were paralytic. Neither the number of active pixels nor the mean value of their activations differed between the seven arms with good biceps function and control arms. The weighted center of gravity of the distribution of activity also did not appear to differ. CONCLUSIONS: Reactivation of the neural input activity for volitional biceps control after ICN-MCN transfer, as reflected on fMR images, is induced by successful biceps muscle reinnervation. In addition, the restored input activity does not differ from the normal activity regulating biceps contraction and, therefore, has MCN acceptor qualities. After ICN-MCN transfer, cerebral activity cannot reach the biceps muscle following the normal nervous system pathway. The presence of a common input response between corticospinal neurons of the ICN donor and the MCN acceptor seems crucial to obtain a functional result after transfer. It may even be the case that a common input response between donor and acceptor needs to be present in all types of nerve transfer to become functionally effective.

Adolescent↗
PubMed2002

Nerve root repair.

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Brachial Plexus↗