Effects of local continuous release of brain derived neurotrophic factor (BDNF) on peripheral nerve regeneration in a rat model

The purpose of this study was to evaluate the effect of continuously released BDNF on peripheral nerve regeneration in a rat model. Initial in vitro evaluation of calcium alginate prolonged-release-capsules (PRC) proved a consistent release of BDNF for a minimum of 8 weeks. In vivo, a worst case scenario was created by surgical removal of a 20-mm section of the sciatic nerve of the rat. Twenty-four autologous fascia tubes were filled with calcium alginate spheres and sutured to the epineurium of both nerve ends. The animals were divided into 3 groups. In group 1, the fascial tube contained plain calcium alginate spheres. In groups 2 and 3, the fascial tube contained calcium alginate spheres with BDNF alone or BDNF stabilized with bovine serum albumin, respectively. The autocannibalization of the operated extremity was clinically assessed and documented in 12 additional rats. The regeneration was evaluated histologically at 4 weeks and 10 weeks in a blinded manner. The length of nerve fibers and the numbers of axons formed in the tube was measured. Over a 10-week period, axons have grown significantly faster in groups 2 and 3 with continuously released BDNF compared to the control. The rats treated with BDNF (groups 2 and 3) demonstrated significantly less autocannibalization than the control group (group 1). These results suggest that BDNF may not only stimulate faster peripheral nerve regeneration provided there is an ideal, biodegradable continuous delivery system but that it significantly reduces the neuropathic pain in the rat model.

Nerve-sparing open radical retropubic prostatectomy

INTRODUCTION: In recent years, the surgical technique for open radical prostatectomy has evolved and increasing attention is paid to preserving anatomic structures and the impact on outcome and quality of life. METHODS: Technical aspects of nerve-sparing open radical retropubic prostatectomy (RRP) are described. Patient selection criteria and functional results are discussed, focusing on postoperative urinary continence. RESULTS: The video demonstrates the nerve-sparing open RRP and important steps are elucidated with schematic drawings. The value of nerve sparing, not only for preserving erectile function, but also for preserving urinary continence is discussed and results from our institution are presented. In our series, urinary incontinence was present in 1 of 71 patients (1%) with attempted bilateral nerve-sparing, 11 of 322 (3%) with attempted unilateral nerve-sparing, or 19 of 139 (14%) without attempted nerve-sparing surgery. In multiple logistic regression analysis, the only statistically significant factor influencing urinary continence after open RRP was attempted nerve sparing (odds ratio, 4.77; 95% confidence interval, 2.18-10.44; p=0.0001). CONCLUSIONS: Nerve-sparing surgery has a significant impact on erectile function and urinary continence and should be performed in all patients provided radical tumour resection is not compromised. For successful nerve preservation we advocate a lateral approach to the prostate to improve visualisation and simplify separation of the neurovascular bundles from the dorsolateral prostatic capsule. Bunching, ligating, and incising Santorini's plexus over the prostate and not over the sphincter ensures a bloodless surgical field. Mucosa-to-mucosa adaptation of the reconstructed bladder neck and the urethra is another important factor to be observed.

Nerve sparing open radical retropubic prostatectomy--does it have an impact on urinary continence?

PURPOSE: We prospectively assessed the role of nerve sparing surgery on urinary continence after open radical retropubic prostatectomy. MATERIALS AND METHODS: We evaluated a consecutive series of 536 patients who underwent open radical retropubic prostatectomy with attempted bilateral, unilateral or no nerve sparing, as defined by the surgeon, without prior radiotherapy at a minimum followup of 1 year with documented assessment of urinary continence status. Because outlet obstruction may influence continence rates, its incidence and management was also evaluated. RESULTS: One year after surgery 505 of 536 patients (94.2%) were continent, 27 (5%) had grade I stress incontinence and 4 (0.8%) had grade II stress incontinence. Incontinence was found in 1 of 75 (1.3%), 11 of 322 (3.4%) and 19 of 139 patients (13.7%) with attempted bilateral, attempted unilateral and without attempted nerve sparing, respectively. The proportional differences were highly significant, favoring a nerve sparing technique (p <0.0001). On multiple logistic regression analysis attempted nerve sparing was the only statistically significant factor influencing urinary continence after open radical retropubic prostatectomy (OR 4.77, 95% CI 2.18 to 10.44, p = 0.0001). Outlet obstruction at the anastomotic site in 33 of the 536 men (6.2%) developed at a median of 8 weeks (IQR 4 to 12) and was managed by dilation or an endoscopic procedure. CONCLUSIONS: The incidence of incontinence after open radical retropubic prostatectomy is low and continence is highly associated with a nerve sparing technique. Therefore, nerve sparing should be attempted in all patients if the principles of oncological surgery are not compromised.

Horizontal ridge augmentation using autogenous block grafts and the guided bone regeneration technique with collagen membranes: a clinical study with 42 patients

OBJECTIVE: To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with an organic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. MATERIAL AND METHODS: In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. RESULTS: Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2-7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. CONCLUSIONS: The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure.

Model-based control of neuromuscular block using mivacurium: design and clinical verification

BACKGROUND: Short-acting agents for neuromuscular block (NMB) require frequent dosing adjustments for individual patient's needs. In this study, we verified a new closed-loop controller for mivacurium dosing in clinical trials. METHODS: Fifteen patients were studied. T1% measured with electromyography was used as input signal for the model-based controller. After induction of propofol/opiate anaesthesia, stabilization of baseline electromyography signal was awaited and a bolus of 0.3 mg kg-1 mivacurium was then administered to facilitate endotracheal intubation. Closed-loop infusion was started thereafter, targeting a neuromuscular block of 90%. Setpoint deviation, the number of manual interventions and surgeon's complaints were recorded. Drug use and its variability between and within patients were evaluated. RESULTS: Median time of closed-loop control for the 11 patients included in the data processing was 135 [89-336] min (median [range]). Four patients had to be excluded because of sensor problems. Mean absolute deviation from setpoint was 1.8 +/- 0.9 T1%. Neither manual interventions nor complaints from the surgeons were recorded. Mean necessary mivacurium infusion rate was 7.0 +/- 2.2 microg kg-1 min-1. Intrapatient variability of mean infusion rates over 30-min interval showed high differences up to a factor of 1.8 between highest and lowest requirement in the same patient. CONCLUSIONS: Neuromuscular block can precisely be controlled with mivacurium using our model-based controller. The amount of mivacurium needed to maintain T1% at defined constant levels differed largely between and within patients. Closed-loop control seems therefore advantageous to automatically maintain neuromuscular block at constant levels.

[Intraoral lipoma in the region of the mental nerve--report of a case and review of the literature]

The intraoral lipoma is a benign, slowly growing, painless soft tissue neoplasia, which can cause esthetic or functional problems for the patient, depending on its size. All parts of the body can be affected, whereas the oral cavity is rarely involved. Clinically, the tumour often exhibits an exophytic growth pattern, a soft consistency, a broad base connected to the underlying tissue, and frequently has a reddish-yellowish colour. Instead of a superficial mucosal involvement, a deep localization in the soft tissues is also possible. Depending on the localization of the tumour, the diagnosis and the resulting therapy can turn out to be a challenge for the clinician. A clear differentiation to malign neoplasias of the fat tissues and other soft tissue expansions is essential. The following case report presents a female patient who is affected by a lipoma in the proximity of the mental nerve. The diagnostic work-up and resulting therapy including a review of the current literature are presented and discussed.