Non-invasive stimulation of the vibrissal pad improves recovery of whisking function after simultaneous lesion of the facial and infraorbital nerves in rats.

We have recently shown that manual stimulation of target muscles promotes functional recovery after transection and surgical repair to pure motor nerves (facial: whisking and blink reflex; hypoglossal: tongue position). However, following facial nerve repair, manual stimulation is detrimental if sensory afferent input is eliminated by, e.g., infraorbital nerve extirpation. To further understand the interplay between sensory input and motor recovery, we performed simultaneous cut-and-suture lesions on both the facial and the infraorbital nerves and examined whether stimulation of the sensory afferents from the vibrissae by a forced use would improve motor recovery. The efficacy of 3 treatment paradigms was assessed: removal of the contralateral vibrissae to ensure a maximal use of the ipsilateral ones (vibrissal stimulation; Group 2), manual stimulation of the ipsilateral vibrissal muscles (Group 3), and vibrissal stimulation followed by manual stimulation (Group 4). Data were compared to controls which underwent surgery but did not receive any treatment (Group 1). Four months after surgery, all three treatments significantly improved the amplitude of vibrissal whisking to 30° versus 11° in the controls of Group 1. The three treatments also reduced the degree of polyneuronal innervation of target muscle fibers to 37% versus 58% in Group 1. These findings indicate that forced vibrissal use and manual stimulation, either alone or sequentially, reduce target muscle polyinnervation and improve recovery of whisking function when both the sensory and the motor components of the trigemino-facial system regenerate.

Four-digit replantation in a mentally retarded person: a case report.

This report describes a case where 4 digits were replanted in a mentally retarded patient with a history of smoking and the inability to follow postoperative arrangements.

[Limited portal carpal tunnel release. An alternative to classic open release?]. / Die minimal-invasive Karpaltunnelspaltung. Eine Alternative zur klassischen offenen Spaltung?

The aim of this study was to determine the significance of limited portal carpal tunnel release compared to the classic open approach. We present a retrospective comparative clinical trial including 161 patients (105 open release and 56 limited portal release). Special interest was directed towards postoperative functionality, disorders and quality of life. Significant advantages could be demonstrated for the limited portal carpal tunnel release: rapid ability to return to work as well as to routine tasks of daily living and high patient satisfaction. In the hands of trained surgeons, limited portal carpal tunnel release represents a rewarding alternative to the classic open release.

[Does additive spongiosaplasty improve outcome after surgical therapy for solitary enchondroma in the hand?]. / Einfluss der Spongiosaplastik auf die Behandlungsergebnisse nach chirurgischer Therapie solitärer Enchondrome der Hand.

INTRODUCTION: The necessity of spongiosaplasty in the treatment of solitary enchondroma in the hand has been a subject of controversial discussions for several years. Over a period of 10 years the authors performed single curettage without spongiosaplasty. The aim of this study was to investigate our results and to compare these findings with those of other studies. PATIENTS AND METHOD: Over the last 10 years we have treated 106 patients with solitary enchondroma of the hand by single curettage without bone grafting. All patients underwent postoperative radiological examination. The mean follow-up was 34 months. The results of the X-ray investigation were examined retrospectively concerning the recurrence rates and the Hasselgren score. RESULTS: Two patients (1.9%) have experienced radiological changes according to Hasselgren score IV. One patient (0.8%) demonstrated radiological III° changes according to score of Hasselgren. Including the patient with the radiological changes according to Hasselgren score III, the overall recurrence rate was 2.8%. DISCUSSION: After comparing our results with those of other studies, we conclude that additional bone-grafting does not improve the recurrence rate of solitary enchondromas of the hand.

Recovery of whisking function after manual stimulation of denervated vibrissal muscles requires brain-derived neurotrophic factor and its receptor tyrosine kinase B.

Functional recovery following facial nerve injury is poor. Neuromuscular junctions (NMJs) are "bridged" by terminal Schwann cells and numerous regenerating axonal sprouts. We have shown that this poly-innervation of NMJs can be reduced by manual stimulation (MS) with restoration of whisking function. In addition, we have recently reported that insulin-like growth factor-1 (IGF-1) is required to mediate the beneficial effects of MS. Here we extend our findings to brain derived neurotrophic factor (BDNF). We then examined the effect of MS after facial-facial anastomosis (FFA) in heterozygous mice deficient in BDNF (BDNF(+/-)) or in its receptor TrkB (TrkB(+/-)). We quantified vibrissal motor performance and the percentage of NMJ bridged by S100-positive terminal Schwann cells. In intact BDNF(+/-) or TrkB(+/-) mice and their wild type (WT) littermates, there were no differences in vibrissal whisking nor in the percentage of bridged NMJ (0% in each genotype). After FFA and handling alone (i.e. no MS) in WT animals, vibrissal whisking amplitude was reduced (60% lower than intact) and the percentage of bridged NMJ increased (27% more than intact). MS improved both the amplitude of vibrissal whisking (not significantly different from intact) and the percentage of bridged NMJ (11% more than intact). After FFA and handling in BDNF(+/-) or TrkB(+/-) mice, whisking amplitude was again reduced (53% and 60% lower than intact) and proportion of bridged NMJ increased (24% and 29% more than intact). However, MS failed to improve outcome in both heterozygous strains (whisking amplitude 55% and 58% lower than intact; proportion of bridged NMJ 27% and 18% more than intact). We conclude that BDNF and TRkB are required to mediate the effects of MS on target muscle reinnervation and recovery of whisking function.

Recovery of whisking function promoted by manual stimulation of the vibrissal muscles after facial nerve injury requires insulin-like growth factor 1 (IGF-1).

Recently, we showed that manual stimulation (MS) of denervated vibrissal muscles enhanced functional recovery following facial nerve cut and suture (FFA) by reducing poly-innervation at the neuro-muscular junctions (NMJ). Although the cellular correlates of poly-innervation are established, with terminal Schwann cells (TSC) processes attracting axon sprouts to "bridge" adjacent NMJ, molecular correlates are poorly understood. Since quantitative RT-PCR revealed a rapid increase of IGF-1 mRNA in denervated muscles, we examined the effect of daily MS for 2 months after FFA in IGF-1(+/-) heterozygous mice; controls were wild-type (WT) littermates including intact animals. We quantified vibrissal motor performance and the percentage of NMJ bridged by S100-positive TSC. There were no differences between intact WT and IGF-1(+/-) mice for vibrissal whisking amplitude (48 degrees and 49 degrees ) or the percentage of bridged NMJ (0%). After FFA and handling alone (i.e. no MS) in WT animals, vibrissal whisking amplitude was reduced (60% lower than intact) and the percentage of bridged NMJ increased (42% more than intact). MS improved both the amplitude of vibrissal whisking (not significantly different from intact) and the percentage of bridged NMJ (12% more than intact). After FFA and handling in IGF-1(+/-) mice, the pattern was similar (whisking amplitude 57% lower than intact; proportion of bridged NMJ 42% more than intact). However, MS did not improve outcome (whisking amplitude 47% lower than intact; proportion of bridged NMJ 40% more than intact). We conclude that IGF-I is required to mediate the effects of MS on target muscle reinnervation and recovery of whisking function.

[Is intraoperative luxation of the ulnar nerve a criterion for transposition?]. / Ist die intraoperative Ulnarisluxation ein Kriterium für die Vorverlagerung?

BACKGROUND: The relevance of subcutaneous transposition of the ulnar nerve in the therapy of cubital tunnel syndrome is still under debate. The aim of this study was to compare the results after decompression to additional transposition in cases of intraoperative luxation. METHODS: A total of 54 cases after surgery of cubital tunnel syndrome between 2000 and 2006 were analyzed. Nerve transposition was performed in cases of intraoperatively apparent nerve luxation. RESULTS: Of the patients 12 were treated by decompression alone and 42 by additional subcutaneous transposition. There was no significant difference concerning symptom amelioration, usage properties of the hand, sensation impairment and duration of disability. Force measurements of grip strength and pinch strength revealed no significant differences between either hand in both groups. The 2-point discrimination ability of the 8th to 10th finger nerves was not significantly different between the groups either. CONCLUSION: Nerve transposition revealed no benefits in the treatment of cubital tunnel syndrome when performed in cases of intraoperative nerve luxation.

[Nerve reconstruction and nerve grafting]. / Nervenrekonstruktion und Nervenersatzoperationen.

The surgical treatment of peripheral nerve injuries is still a challenging and highly demanding procedure. Past results have been improved upon by different advances in microsurgical techniques and algorithms. Nevertheless, results are not always satisfying, making secondary procedures necessary. Thus, these secondary procedures such as tendon transfers and arthrodesis of different joints must be taken into account during reconstructive planning. This review gives an overview of peripheral nerve reconstruction (nerve grafting, nerve repair) and the pertinent secondary procedures.

Concepts and developments in peripheral nerve surgery.

Nerve injuries may result in sensory and motor deficits when not treated appropriately. Especially the surgical management of nerve defects still represents a challenge for the surgeon. In these cases the grafting of autologous nerves represents the only reasonable approach. Due to the side effects associated with this method (sacrifice of donor nerves, neuroma formation in the harvesting area, limited availability of donor nerves, etc.), numerous alternatives were proposed in order to avoid the transplantation of autologous tissue. This review provides a general view on the state of the art of how to supply gaping injuries in the peripheral nerve. Furthermore new approaches emphasizing tubulization techniques for the reconstruction of lost nerve tissue are described with a special focus on various materials with their advantages and disadvantages.

[Recurrence rates of venous leg ulcers and the special importance of its surgical treatment]. / Rezidivraten des venösen ulkus unter chirurgischer therapie.

BACKGROUND: Venous insufficiency may lead to recurrent leg ulcers. The reason for this observation remains still unclear. In this study we tried to underline the influence of surgical treatment on recurrence rate of venous leg ulcers. PATIENTS AND METHODS: In this study 69 patients were treated in a special wound care centre. Before treatment the angiological status was evaluated using phlebography or duplex scan. Afterwards, patients were scored according to the "Venous Clinical Severity Score" of the American Venous Forum. During the observation period compression therapy was performed and wounds were treated with moist dressings. Necroses were removed by radical debridement and large ulcers were covered by mesh graft tissue transfer. When indicated incompetent veins were treated surgically. RESULTS: The follow-up revealed an overall recurrence rate of 21 % after 30 months. Ulcers treated by radical wound debridement or mesh graft tissue transfer demonstrated a significant lower recurrence rate (p = 0.02 and p = 0.03). According to duplex sonography a correlation was evident among severity of venous insufficiency, the "clinical scoring" (p = 0.04), and the recurrence rate (p = 0.023). After surgical intervention by venous stripping, the insufficiency was improved but the recurrence rate was comparable to that of patients treated without venous surgery (p = 0.44). CONCLUSION: Surgical treatment of venous leg ulcers in modern wound care centres can reduce its recurrence rates. Herein this study a correlation among venous insufficiency evidenced by duplex scan and recurrence rate for leg ulcers could be demonstrated.

Manual stimulation of forearm muscles does not improve recovery of motor function after injury to a mixed peripheral nerve.

Transection and re-anastomosis of the purely motor facial nerve leads to poor functional recovery. However, we have recently shown in rat that manual stimulation (MS) of denervated vibrissal muscles reduces the number of polyinnervated motor endplates and promotes full recovery of whisking. Here, we examined whether MS of denervated rat forearm muscles would also improve recovery following transection and suture of the mixed (sensory and motor) median nerve (median-median anastomosis, MMA). Following MMA of the right median nerve, animals received no postoperative treatment, daily MS of the forearm muscles or handling only. An almost identical level of functional recovery, measured by the force of grip in grams, was reached in all animals by the sixth postoperative week and maintained till 3 months following surgery regardless of the postoperative treatment. Also, we found no differences among the groups in the degree of axonal sprouting, the extent of motor endplate polyinnervation and in the soma size of regenerated motoneurons. Taken together, we show that while MS is beneficial following motor nerve injury, combined strategies will be required for functional recovery following mixed nerve injury.

Comparative neuro tissue engineering using different nerve guide implants.

At the moment autologous nerve grafting remains the only reasonable technique for reconstruction of peripheral nerve defects. Unfortunately, this technique has a lot of complications and disadvantages. These problems are related to the autologous nerve that is harvested for this procedure. Donor site morbidity with loss of sensitivity, painful neuroma formation and of course the restricted availability of autologous nerves stimulates the idea for alternative techniques on that field. In this paper we describe our experience with different graft materials for reconstruction of a 2 cm nerve gap in a median nerve model in rats. After implantation of various materials (biological/synthetic) the main experiments were conducted with a synthetic, biodegradable nerve conduit seeded with autologous Schwann cells. With this material we were able to reconstruct successfully a 2 cm gap in the rat median nerve. Regeneration with this material was found to be equally to an autologous nerve graft.

[Memantine and Complex Regional Pain Syndrome (CRPS): effects of treatment and cortical reorganisation]. / Memantine und komplexes regionales Schmerzsyndrom (CRPS): Behandlungseffekte und kortikale Reorganisation.

BACKGROUND: In recent studies a central nervous system involvement in the pathogenesis of Complex Regional Pain Syndrome (CRPS) was suggested, stimulating the introduction of central acting drugs. Animal studies have demonstrated an increased expression of the N-methyl-D-aspartate (NMDA) receptors in experimental neuropathic pain. PURPOSE: The aim of this study was to investigate the relationship between NMDA receptor blockers and CRPS. METHOD: Three patients suffering from CRPS of one upper extremity where treated with oral NMDA antagonist Memantine for eight weeks. Patients expressed their pain levels with a visual analog scale ranging from zero to ten at rest and after fist clenching. Furthermore, the range of movement of the fingers and the wrist were documented. To assess force, a pinchmeter and a dynamometer were used. Cortical reorganisation was studied with functional Magnetic Resonance Imaging (fMRI) and Magnetoencephalography (MEG). RESULTS: Six months after treatment with Memantine no rest pain was present in any of the patients. Furthermore, an increase in finger movement was observed after six-month follow-up with no deficits and free movement ranges. Additionally, wrist movement was improved and an increase of force was measured after six months with the dynamometer and the pinchmeter. Moreover the functional impairment, cortical reorganisation was observed in all patients before treatment. These changes returned to a normal pattern after eight weeks of treatment with Memantine. CONCLUSION: These first results demonstrate central nervous system involvement in the development and maintenance of CRPS. The results (functional, pain, fMRI, MEG) after treatment with Memantine indicate the importance of the NMDA receptor system in neuropathic pain syndromes and provide a promising approach for the treatment of CRPS.

[Tissue engineering of peripheral nerves]. / Tissue Engineering peripherer Nerven.

BACKGROUND: In spite of considerable progress in microsurgical techniques, the treatment of long distance defects in peripheral nerves remains challenging for the surgeon. Autologous nerve grafting has been the only applicable procedure to overcome such defects in the past. Due to the known disadvantages of this procedure (neuroma formation and sensory deficits at the donor-site, limited availability of donor-material, etc.) and impaired regenerative results, different tubulisation techniques are discussed more frequently as alternatives to the autologous nerve grafts. AIM OF THE STUDY: In this work, the authors summarise their experiences and results with different synthetically developed materials, cellular and acellular tubes and venous conduits for the reconstruction of peripheral nerve defects. MATERIAL AND METHODS: To analyse peripheral nerve regeneration, we utilised a median nerve model in rats. In these studies nerve gaps up to 40 mm were induced. Guiding tubes of various materials (trimethylene carbonate-epsilon-caprolactone, polyethylene, veins, and collagen) were employed. Furthermore, we introduced Schwann cells as cellular elements into some of the trimethylene carbonate-epsilon-caprolactone tubes. The longest postoperative observation period was nine months. RESULTS: The results demonstrated that only in the case of cellular filled tubes (syngenic Schwann cells) did regeneration occur across the 20 mm gap. This regeneration was comparable to that induced after autologous grafting. Across a 40 mm gap the autologous graft demonstrated the best results.