Thoracic epidural puncture guided by an acoustic signal: clinical results

BACKGROUND AND OBJECTIVE: In previous studies we have demonstrated that it is possible and safe to identify the lumbar epidural space by an acoustic and visible signal. The use of an experimental set-up constructed for this purpose, the acoustic puncture assist device, the lumbar epidural puncture procedure became both audible and visible. In the present study we have extended the use of the device to localize the thoracic epidural space. We have also evaluated whether the device can be used as a practical tool to confirm correct catheter placement. METHODS: In 100 consecutive patients a prototype of the acoustic puncture assist device was connected to the epidural needle in order to localize the epidural space. The device translates the pressure encountered by the needle tip into a corresponding acoustic and visible signal and enables the anaesthesiologist to detect the epidural space by means of the acoustic signal. After catheter insertion, local anaesthetic was administered. Subsequently the epidural block was tested. In 10 patients the device was also connected to the epidural catheter after its insertion into the epidural space. RESULTS: In all 100 patients included in the study the epidural space was successfully located by means of the acoustic signal. The only recorded complication was intravascular catheter placement in two patients. CONCLUSIONS: It is possible to localize the thoracic epidural space guided by an acoustic signal. The method was shown to be safe, reliable and simple. Potential implications of this technique include better needle control, improved monitoring for training purposes and for clinical documentation of the thoracic epidural puncture as well as identifying correct catheter placement.     

Electrical stimulation of denervated muscles: first results of a clinical study

To evaluate the effects of electrical stimulation on denervated muscles in spinal cord injured humans, the EU Project RISE was started in 2001. The aims of this project are: to design and build sufficient stimulators; to develop stimulation protocols by means of mathematical models, animal experiments, and practice in humans with denervated lower limbs; to develop examination methods and devices for evaluation of electrical stimulation training effects; and to acquire basic scientific knowledge on denervated and stimulated denervated muscle. In the clinical study 27 spinal cord injured individuals were included, furthermore 13 pilot patients participated. After a series of initial examinations they underwent an electrical stimulation program for their denervated lower limb muscles. Some of the patients have already follow up examinations. A marked increase of muscle mass and quality was observed, the trophic situation of the denervated lower limbs had improved obviously.     

The ProSeal-LM, a new variant of the laryngeal mask: description and first clinical results

The ProSeal-LMA is a modification of the laryngeal mask airway (LMA) invented by AIJ Brain. It differs from the known models in three major respects: An additional lumen extending into the tip of the cuff allows insertion of a gastric tube. A pocket immediately behind the cuff accommodates a finger or a siliconated metal introducer and thus facilitates insertion. An additional cuff at the dorsal aspect of the mask pushes the mask into a ventral direction and thus improves the seal around the glottic opening. Our experience after 8 months of clinical use and first data from an international multi-center-study (24 ProSeal-LMA/24 Standard-LMA) are reported. With a ProSeal-LMA insertion of a gastric tube is much easier and more reliable than with a Standard-LMA (24/24 patients vs. 2/24 patients). Judged from visibility of the oesophagus during fibre-endoscopy the position of the ProSeal-LMA is superior to that of the Standard-LMA. Both are equally well tolerated and handled. Most remarkable is a better seal for the ProSeal-LMA (pressure for a leak of 3 L/min: 31 mbar compared to 20 mbar (mean) for the Standard-LMA). Therefore the ProSeal-LMA seems suitable for anaesthesia procedures with IPPV, which up to now are a domain of endotracheal intubation.     

Robot-assisted navigated endoscopic ventriculostomy: implementation of a new technology and first clinical results

Summary Background. Important landmarks in the evolution of advanced neurosurgical techniques during the past decades include microneurosurgery, neuro-endoscopy and its minimally invasive nature, as well as neuronavigation and advanced intra-operative imaging. With conventional neuroendoscopic techniques, e.g. free-hand endoscopy or the use of mechanical or pneumatic holding devices, a definitive and controlled movement of the endoscope within the brain does depend on the experience and manual skill of the individual neurosurgeon. Therefore, the development of robotic systems to assist surgeons in performing complex neurosurgical procedures is a growing field of interest. Method. With the precision robot Evolution 1 (U.R.S. Universal Robot Systems, Schwerin, Germany) a new neurosurgical tool has just become available for the precise steering of instruments within the cranium. After preclinical anatomical as well as precision studies the system was used for robot-assisted navigated endoscopic third ventriculostomies in six patients with hydrocephalus related to aqueductal stenosis. Findings. All robot-assisted navigated endoscopic procedures were successfully completed. The time for the registration procedure and setup of the robot decreased from 60min. for the first procedure down to 30min. The time for the surgical part of the neuro-endoscopic procedure itself ranged from 17 to 35min. During all procedures no system-related complications occured. Interpretation. The use of robotic technology for neuro-endoscopic third ventriculostomies is a major step towards the controlled movement of the neuro-endoscope within the cranium. The start up procedure and calibration of the robot is still time consuming, but the real operation time is comparable to free hand neuro-endoscopy. The steering of the endoscope is facilitated and the precision of the endoscopic movements is noteworthy.     

Experimental and clinical results of grafts in the venous system: a current review.

A review of recent experimental and clinical studies of grafts in the venous system indicates that: (1) the autogenous vein remains the best material for segmental venous replacement; (2) recanalization can occur with synthetic grafts; (3) early venography should be utilized to aid in the differentiation of recanalization from continued primary patency; (4) distal arteriovenous fistulas can be used temporarily to improve long-term patency rates; (5) systemic inhibitors of platelet aggregation may be useful in selected circumstances; and (6) alteration of the prosthesis—blood interface remains a potential area of investigation. We urge that further studies: (1) recognize the need for thorough and concise reporting of materials and methods, (2) include early and late venographic observations, and (3) critically examine the importance of porosity, prosthesis healing, and endothelium upon early and long-term patency of venous substitutes.     

Percutaneous renal cyst puncture: unusual results in 2 cases.

Percutaneous puncture and aspiration were used successfully in 2 cases: 1) a calcified benign renal cyst and 2) a grossly infected benign renal cyst. Percutaneous aspiration might be a useful procedure in either calcified or infected renal cyst. If percutaneous puncture is contemplated in a calcified ring lesion, preliminary angiography is strongly recommended to exclude possible renal artery aneurysm or arteriovenous malformation.     

Ulnar-basilic fistula: indications, surgical aspects, puncture technique, and results

Ulnar-basilic fistula (UBF) is an autogenic vascular access option for hemodialysis (HD) first reported in 1967. However, only a few reports dealing with its complications and survival rates have been published in the literature. In the present work the results of 61 UBFs done in 60 adult patients on chronic HD are reported. Forty UBFs were created as primary access and the remaining 21 UBF as secondary access after: (a) thrombosis of an ipsilateral radiocephalic fistula (RCF) in 6 cases, (b) thrombosis of a contralateral RCF in 7 cases, and (c) thrombosis of a brachiocephalic fistula in 2 cases. No episodes of surgical complications, arterial steal, or ulnar nerve damage were observed. Five UBFs thrombosed within the first week after surgery. The 1-, 3-, and 5-year unassisted survival rates were 70.9%, 67.7%, and 57.3%, respectively, which were significantly higher than those reported previously. The inclusion of UBF in routine access plans is recommended.     

Pranlukast, a novel leukotriene receptor antagonist: results of the first European, placebo controlled, multicentre clinical study in asthma

BACKGROUND: Leukotriene receptor antagonists have been shown to protect against bronchoconstriction induced by antigens, exercise, and cold air. There are relatively few clinical studies reported in patients with asthma. The present study is the first clinical evaluation of pranlukast (SB 205312, ONO-1078) outside Japan in patients with asthma. METHODS: A randomised, double blind, placebo controlled, parallel group, multicentre four week study of the safety and tolerability of oral pranlukast, 225 or 337.5 mg twice daily, was performed in patients with mild to moderate asthma. Preliminary efficacy data were obtained; the main efficacy variables evaluated were forced expiratory volume in one second (FEV1) and morning domiciliary (home) peak expiratory flow rates (PEFR). Clinic PEFR and daytime and night-time asthma symptom scores were also recorded. RESULTS: Compared with the placebo group the improvement in morning home PEFR was statistically significant at all time points for patients receiving pranlukast 337.5 mg twice daily and at weeks 1 and 2 for those treated with pranlukast in a dose of 225 mg twice daily. Mean morning home PEFR increased by 10.8 to 18.61/min (95% CI 0.2 to 29.3 l/min) in patients treated with pranlukast compared with a slight deterioration in those given placebo. FEV1 significantly increased within one hour after the first dose of pranlukast compared with baseline and this increase was maintained for eight hours. Improvements in trough FEV1-that is, at the end of the dosing interval- were statistically significant for the group treated with pranlukast 225 mg twice daily compared with placebo at week 4. Mean increases in FEV1 ranged from 210 ml to 340 ml (95% CI 60 to 500 ml) at trough in the pranlukast group. Patients treated with pranlukast also showed improvements in summary symptom and night-time asthma scores. Pranlukast was well tolerated, and no drug related changes in haematological and biochemical variables were observed. CONCLUSIONS: Pranlukast, an oral leukotriene receptor antagonist, is well tolerated and is effective for the treatment of asthma. It increased FEV1 within one hour of dosing, improved patient summary symptom and night-time asthma scores, and reduced the use of rescue bronchodilators, thus providing further evidence of a role for leukotrienes in the pathogenesis of asthma.


     

Prostate cancer diagnosis using ultrasound elastography. Introduction of a novel technique and first clinical results

During the last decade screening has improved prostate cancer detection. The main reason for this development is a better understanding of the margins of prostate-specific antigen (PSA) serum levels and the classification of PSA subtypes. In contrast, the introduction of transrectal ultrasound has not led to a measurable change in the prostate cancer detection rate. Our aim was to develop a novel ultrasound system for the acquisition of elastographic images of the prostate and evaluate the system regarding its clinical applicability. We used a technically modified conventional ultrasound system and analyzed the high-frequency ultrasonic data with a computer program. The first patient-based results suggest that elastography allows an accurate measurement of tumor size and localization in contrast to conventional transrectal ultrasound. Elastography visualizes different tissue elasticities to distinguish benign and cancerous tissue. Thus, we were able to even correctly classify prostate cancer lesions which are iso- or hyperechoic in B-mode sonography.     

Madelung deformity: clinical features, therapy and results.

In a retrospective study, 31 patients with Madelung deformity were reviewed. They were treated at one institution during a period of 15 years. On first presentation, the mean age was 22.5 years with a range from 10 years to 64 years. Twenty-four patients (77%) were female. The main complaints were pain, limited range of motion, and objectionable appearance. A family history of Madelung deformity was present in four patients (13%). The diagnosis of Leri-Weill syndrome could not be confirmed in any case. There was no correlation between the clinical appearance and the extent of radiologic abnormality. Five patients (16%) were operated on because of permanent pain. On postoperative examination, only one patient revealed no restricted range of mobility and no pain, whereas the other four patients improved in terms of pain but showed only limited improvement of function. The vast majority of patients, however, required no surgical therapy.     

The first clinical application of a "hands-on" robotic knee surgery system.

The performance of a novel "hands-on" robotic system for total knee replacement (TKR) surgery is evaluated. An integrated robotic system for accurately machining the bone surfaces in TKR surgery is described. Details of the system, comprising an "active constraint" robot, called Acrobot, a "gross positioning" robot, and patient clamps, are provided. The intraoperative protocol and the preoperative, CT-based, planning system are also described. A number of anatomical registration and cutting trials, using plastic bones, are described, followed by results from two preliminary clinical trials, which demonstrate the accuracy achieved in the anatomical registration. Finally, the first clinical trial is described, in which the results of the anatomical registration and bone cutting are seen to be of high quality. The Acrobot system has been successfully used to accurately register and cut the knee bones in TKR surgery. This demonstrates the great potential of a "hands-on" robot for improving accuracy and increasing safety in surgery.     

Computer-assisted LISS plate osteosynthesis of proximal tibia fractures: feasibility study and first clinical results.

Fluoroscopy is the most common tool for the intraoperative control of long-bone fracture reduction. Limitations of this technology include high radiation exposure for the patient and the surgical team, limited visual field, distorted images, and cumbersome verification of image updating. Fluoroscopy-based navigation systems partially address these limitations by allowing fluoroscopic images to be used for real-time surgical localization and instrument tracking. Existing fluoroscopy-based navigation systems are still limited as far as the virtual representation of true surgical reality is concerned. This article, for the first time, presents a reality-enhanced virtual fluoroscopy with radiation-free updates of in situ surgical fluoroscopic images to control metaphyseal fracture reduction. A virtual fluoroscopy is created using the projection properties of the fluoroscope; it allows the display of detailed three-dimensional (3D) geometric models of surgical tools and implants superimposed on the X-ray images. Starting from multiple registered fluoroscopy images, a virtual 3D cylinder model for each principal bone fragment is constructed. This spatial cylinder model not only supplies a 3D image of the fracture, but also allows effective fragment projection recovery from the fluoroscopic images and enables radiation-free updates of in situ surgical fluoroscopic images by non-linear interpolation and warping algorithms. Initial clinical experience was gained during four tibia fracture fixations that were treated by LISS (Less Invasive Stabilization System) osteosynthesis. In the cases operated on, after primary image acquisition, the image intensifier was replaced by the virtual reality system. In all cases, the procedure including fracture reduction and LISS osteosynthesis was performed entirely in virtual reality. A significant disadvantage was the unfamiliar operation of this prototype software and the need for an additional operator for the navigation system.     

LD hip arthroplasty. Design concepts and first clinical trials of a new modular system.

The new LD modular hip arthroplasty is made of Ti6A14V. The acetabular component has a hemispheric expansive metallic ring and a polyethylene nucleus in the shape of a cone segment. Since June 1988, when the clinical trials began, 352 arthroplasties have been performed with 112 total hip arthroplasties among them. Only 60 noncemented total hip arthroplasties, with the longest follow-up evaluation reaching 24 months, were analyzed. Patients with revision operations were excluded. The results have been evaluated using the Merle D'Aubigne scoring scale. Good results were found in 86% of cases. Pain improved markedly at three months in the postoperative period. At six months, the Trendelenburg sign was negative in 76% and positive in 12%. The Duchenne sign was positive in 11%. Major complications included three dislocations, two acetabular component revisions caused by initial malposition, one external popliteal nerve palsy, one deep infection, and two periprosthetic fractures. No acetabular migrations have been found. There are six femoral sinkings of less than 1 cm. Heterotopic ossifications Grade II-III appear in 24% of cases. The results to date are evaluated clinically and radiologically. The acetabular design has proved efficient, and the femoral components show a low incidence of stress shielding.     

Vibrography: first experimental results in swine brains.

OBJECT: The aim of this study was to determine whether vibrography, an ultrasound-based real-time strain imaging method for registering the elastic properties of tissue, is superior to conventional ultrasound imaging techniques for detecting low-contrast space-occupying lesions in brain tissue and for delineating the boundaries between such lesions and the surrounding tissue. METHODS: As our experimental model we used swine brains taken from freshly slaughtered pigs. After injecting agarose into these brains at different depths, we compared both the conventional ultrasonographic images and the elastographic images of the region of interest with the corresponding anatomical brain sections. RESULTS: In 83.6 % of the experiments, it was possible to detect the polymerized agarose in the brain tissue with vibrographic techniques. In 17 experiments agarose lesions which were not detectable by ultrasound were visualized via vibrography. Furthermore, statistical analysis revealed that elastography is a more precise tool than conventional ultrasound for determining lesion size. CONCLUSION: These findings indicate that vibrography is a promising real-time imaging method with numerous potential applications in the field of neurosurgery. Visualization of the elastic properties provides the neurosurgeon with additional data on the lesion and the boundary between the lesion and the surrounding tissue.