Update on peripheral nerve microsurgery.
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Humans↗
Biomedical subjects
Marios D Vekris
Publications and source records attributed to Marios D Vekris.
Neuroanatomy of the brachial plexus: the missing link in the continuity between the central and peripheral nervous systems.
The brachial plexus is a complex network of nerves which extends from the neck to the axilla and which supplies motor, sensory, and sympathetic fibers to the upper extremity. Generally it is formed by the union of the ventral primary rami of the spinal nerves, C5-C8 and T1, the so-called "roots" of the brachial plexus. The goal here is to examine the neural architecture of the brachial plexus. The most constant arrangement of nerve fibers will be delineated, and then the predominant variations in neural architecture will be defined, particularly the prefixed and postfixed plexus, as well as the microanatomy and anatomy of the major terminal branches of the plexus. Multiple tracts connect many parts of the nervous system, and multiple ascending and descending tracts connect the peripheral nervous system (PNS) and lower spinal centers with the brain. This reflects that the nervous system is able to extract different pieces of sensory information from its surroundings and encode them separately, and that it is able to control specific aspects of motor behavior using different sets of neurons. Examination of the major sensory or motor pathways reveals a highly and tightly organized nervous system. In particular, at each of many levels, we see fairly exact maps of the world within the brain. In an effort to understand the functional neuroanatomy of the brachial plexus, this paper will focus briefly on the nervous connections of the nerves of the upper extremity with the brain. The goal here is to better understand "what the brain sees" after nerve injury and repair.
Afferent Pathways↗
Repair of the main nerve trunk of the upper limb with end-to-side neurorrhaphy: an experimental study in rabbits.
The aim of this study was to assess the effectiveness of reinnervation using end-to-side neurorrhaphy in the upper extremity of the rabbit. The cut right ulnar nerve was repaired and sutured to the side of the median nerve about 3 cm above the elbow joint. The extent of reinnervation was quantitatively evaluated, as well as the integrity of the intact donor nerve in 36 rabbits randomly treated with fresh or delayed nerve repair with or without perineurotomy. Evaluations included nerve conduction velocity (NCV) of both the ulnar and medial nerves, dry muscle weight, and histologic examination (neurofilament stain and morphometric assessment) at 3 and 6 months postoperatively. NCV recovery rates were 79% and 87% for the ulnar nerve, and 89% and 94% for the median nerve compared to contralateral intact nerves, at 3 and 6 months, respectively. Flexor carpi ulnaris muscle mass measurements revealed a recovery in dry muscle weight of about 81% and 88% at 3 and 6 months, respectively, compared to the intact contralateral flexor carpi ulnaris. Histologic studies with neurofilament staining reveal numerous axonal sprouts at the distal end of the median nerve, indicative of myelinated axonal regeneration. Morphometric analysis demonstrated no difference between fresh and delayed repairs. These results indicate that in the upper extremity of rabbits, end-to-side neurorrhaphy permits axonal regeneration from the intact donor nerve, and is associated with satisfactory recovery. The effect of the procedure on the donor nerve was negligible.
Animals↗
Long-term evaluation of rabbit peripheral nerve repair with end-to-side neurorrhaphy in rabbits.
This study was designed to quantitatively assess long-term end-to-side neurorrhaphy in rabbits. The cut right ulnar nerve was repaired and sutured to the median nerve, in which a perineurial window was created in an end-to-side fashion 3 cm above the elbow joint. Both the extent of the reinnervation and the integrity of the intact donor nerve were evaluated in 36 rabbits randomly treated with fresh or delayed nerve repair. Evaluations included motor nerve conduction velocity (MNCV), dry muscle weight (DMW), and histological examinations at 9 and 12 months postoperatively. The recovery rates of MNCV were 90.1% and 92.8% for the ulnar nerve, and 95.7% and 96.8% for the median nerve, compared to intact contralateral nerves at 9 and 12 months, respectively. MNCV was not detectable for the ulnar nerve in control animals, while it was normal for the median nerve. Recoveries of flexor carpi ulnaris dry muscle weight of about 90.7% and 94.5% were observed at 9 and 12 months postoperatively, respectively. However, muscle mass measurements revealed a recovery of only 31.3% and 27% for control groups at 9 and 12 months postoperatively. The differences between experimental groups and control groups were statistically significant (P < 0.01). Neurofilament and silver stains showed numerous sprouting axons originating from the median nerve to the ulnar nerve. The results indicate that end-to-side neurorrhaphy could induce axonal sprouting from the main nerve trunk of upper limbs in rabbits, leading to useful functional recovery.
Animals↗
Sciatic and peroneal nerve injuries.
In the past, the attitude toward surgical repair of sciatic and peroneal nerve lesions was excessively pessimistic. Refinements of microsurgical technique, nerve conduction studies, and the establishment of indications and optimal timings for surgical interventions have led to significant improvements in outcomes, making repair worthwhile in most cases. Tendon transfers can augment functional outcomes, and are performed as secondary procedures or (in selected cases) in combination with the initial repair. Developments in the basic sciences, bioengineering, and medical imaging may further improve the results of management of these serious nerve injuries.
Algorithms↗
Musculocutaneous neurotization to restore elbow flexion in brachial plexus paralysis.
Brachial plexus injuries may result in devastating paralysis, especially if they involve all the roots. The upper roots are often traumatized, and therefore elbow flexion is usually lost. The prognosis of these injuries is grave if root avulsions are present and the paralysis includes the hand as well. The current management of brachial plexus injuries should be early, aggressive microsurgical reconstruction of the plexus, combining various neurotizations with intraplexus and extraplexus nerve donors. Following this principle, we present the results of musculocutaneous neurotization in our unit, as well as a review of the literature on this subject. Our results are comparable to those reported in the literature, and indicate that the strongest function is achieved after neurotization via intraplexus donors, while some extraplexus donors (i.e., phrenic and accessory nerve) can offer equally strong elbow flexion, especially if they are used in combination. Neurotization of the musculocutaneous nerve should be one of the primary goals in the reconstruction of the injured plexus, since the return of elbow flexion is of paramount importance in daily activity. The restoration of function is ensured if the stronger and healthier motor donors are dedicated to the neurotization of the musculocutaneous nerve. Sometimes in order to match the axonal number of the target to the lower number of axons offered by the donors, two or more donor nerves may be driven to the same target, such as the musculocutaneous nerve.
Adult↗
Secondary reanimation procedures in late obstetrical brachial plexus palsy patients.
The varying degrees of spontaneous reinnervation that occur in untreated obstetrical brachial plexus palsy leave characteristic deformities of the shoulder, elbow, forearm, wrist, and hand. Common sequelae are internal rotation and adduction deformity of the shoulder, elbow flexion contractures, forearm supination deformity, and lack of wrist extension and finger flexion. Early microsurgical reconstruction of the affected plexus leads to a more rewarding overall function of the upper arm, but residual deformities might appear later which are similar, although less serious, than those observed in untreated cases. Secondary procedures of the shoulder, elbow, forearm, and hand will improve the appearance and function of the upper extremity in late cases of obstetrical brachial plexus. Careful preoperative planning is mandatory and a multistage approach should be applied, depending on the type of palsy and the age of the patient.
Arm↗
Non-union of femoral neck fractures with osteonecrosis of the femoral head: treatment with combined free vascularized fibular grafting and subtrochanteric valgus osteotomy.
Femoral neck fractures, frequently complicated by non-union and femoral head osteonecrosis,present a difficult clinical situation, especially when young patients are concerned. Existing treatment options are valgus osteotomy to address the biomechanical factors or bone grafting to address the biologic factor. The authors describe the operative technique and results of combined subtrochanteric valgus osteotomy and free vascularized fibular grafting in management of five young patients with both non-union and avascular necrosis.
Adolescent↗
Diagnosis and management of the osteonecrotic triad of the knee.
Generalized osteonecrosis of the knee may include, in addition to osteonecrosis of the medial femoral condyle that occurs most frequently, osteonecrosis of the patella or the tibial plateau. Such involvement is known as the osteonecrotic triad of the knee. Although the clinical picture of idiopathic osteonecrosis of the medial femoral condyle seems similar to several other disorders, certain distinct features, including its typical location,clinical symptoms, and late onset of cartilaginous erosion, facilitate differential diagnosis. Despite the progress made in the diagnosis and treatment of idiopathic osteonecrosis of the medial femoral condyle, the prognosis remains severe. More than 80% of the patients deteriorate to the extent that surgical reconstruction is necessary, whereas only about 20%of the patients demonstrate spontaneous resolution or no additional deterioration of the osteonecrotic lesion.
Adult↗
Two-stage flexor tendon reconstruction in zone II using a silicone rod and a pedicled intrasynovial graft.
PURPOSE: To evaluate the results of a modified Paneva-Holevich technique for flexor tendon reconstruction in zone II. METHODS: Twenty patients (22 digits) with poor prognosis injuries (Boyes grade 2-5) were reconstructed. The technique included placing a silicone rod and creating a loop between the flexor digitorum profundus (FDP) and the flexor digitorum superficialis (FDS) in the first stage and reflecting the latter as a pedicled graft through the pseudosheath created around the silicone rod in the second stage. RESULTS: After a follow-up period of at least 1 year (mean, 50 mo) the rate of good and excellent results was 82% according to the Buck-Gramco scale and 73% using the modified Strickland scale. CONCLUSIONS: These results compare favorably with those using the classic (Hunter) 2-stage reconstructions with a silicone rod and a free tendon graft. Apart from technical versatility, additional advantages of the technique include using a local intrasynovial graft, the absence of donor site morbidity, and a low rate of postreconstruction tendon ruptures and tenolysis.
Adolescent↗
Botulinum A toxin for treatment of lower limb spasticity in cerebral palsy: gait analysis in 49 patients.
BACKGROUND: Injection of botulinum type A toxin is a new treatment for spasticity. PATIENTS AND METHODS: We evaluated the effect of botulinum A toxin (BTX-A) in the lower limb muscles of patients having cerebral palsy. We tested 49 patients before and, on average, 4 (2-9) months after giving the toxin. The evaluation included 3-dimensional computerized gait analysis, changes in mobility level, using the Gillette Functional Assessment Questionnaire, and gastrocnemius muscle bulk, using ultrasonographic measurements. RESULTS: The patients were divided into 3 groups, according to the site of BTX-A administration (hamstrings, gastrocnemius and multilevel). Those who were injected in the hamstrings showed a significant improvement in only the maximum knee extension angle during the gait cycle. Those with spastic equinus who were injected in the gastrocnemius muscle responded better than the other groups. The ankle angle on the initial contact, terminal stance and pre-swing, maximum dorsiflexion, ankle range of motion, per cent of single support and gait velocity improved significantly. Overall, the patients showed significant improvements in motor skill performance and functional health. INTERPRETATION: Our findings indicate that botulinum type A toxin can be given as an adjuvant to conservative treatment of patients with cerebral palsy.
Adolescent↗
Transient erectile dysfunction associated with intramuscular injection of botulinum toxin type A.
Autonomic nervous system dysfunction occurs rarely after botulinum toxin type A (BTX-A) intramuscular injections. We report a case of a 23-year-old man with spastic diplegia who had transient erectile dysfunction after intramuscular injection of BTX-A (total dosage, 300 IU, body weight 95 kg) in both hamstring muscles. Some investigators believe that the local spread of the toxin is responsible for autonomic dysfunction, while others believe that the transportation of the toxin to the spinal cord via retrograde flow or via the blood flow after entering the circulation are possible mechanisms of neurologic side effects. On the basis of our case, a retrograde axoplasmic flow to the spinal cord could probably occur because the spinal cord level of hamstring muscles is close to spinal cord levels responsible for erection control.
Adult↗
Two-stage flexor tendon reconstruction in zone 2 of the hand in children.
Two-stage flexor tendon reconstruction (Hunter) is indicated in children with extensive adhesions in zone 2 of the hand, with some reservations concerning the patient's age and cooperation. Nine children (mean age 6.9 years) were treated with the modified Paneva-Holevich technique, which has advantages over the classic Hunter reconstructions. It involves an intrasynovial graft (FDS of the injured finger) that is anatomically stable and morphologically more appropriate compared with free grafts. The size of the silicone rod is precisely assessed in the first stage, the proximal tenorrhaphy has healed by the time the second stage is performed, and donor site morbidity is minimized. After a mean follow-up of 40.1 months, the mean total active motion was 196 degrees, and eight patients achieved a good or excellent result according to the Buck-Gramcko and the revised Strickland scale. Staged flexor tendon reconstruction is technically feasible even in very young children. Results in children are comparable to those achieved in adults.
Adolescent↗
Shoulder deformities in obstetric brachial plexus paralysis: a computed tomography study.
Obstetric brachial plexus palsy invariably involves the upper roots. If left untreated, characteristic deformities of the shoulder are common sequelae. The most objective way to investigate these shoulder deformities is computed tomographic (CT) scanning of bilateral upper limbs. In this study, specific measurements on CT scans of bilateral upper extremities were performed in a population of patients with obstetric brachial plexus palsy before and after reconstruction (nerve repairs and secondary procedures). The measurements showed that the restoration of external rotation and the scapula stabilization procedure correct the inclination of the humeral head, improve the joint congruency significantly, and decrease the winging of the scapula, thus improving the kinetics of the shoulder. Periodic CT measurement is an objective method of measuring the changes at the shoulder joint that occur over time during the natural evolution of the obstetric brachial plexus palsy lesion and of documenting the benefits of microsurgical intervention.
Brachial Plexus↗