[Nellix® endovascular aneurysm sealing (EVAS) - a new technology for endovascular management of infrarenal aortic aneurysms]

BACKGROUND

Recently used endografts for envascular aneurysm repair (EVAR) exclude the pathology by fixation at both the proximal and distal landing zone. Due to endoleaks and migration EVAR is associated with a relevant rate of secondary interventions. The Nellix® system (Endologix Inc., CA, USA) was developed to seal the complete aneurysm using a polymer filling, therefore stabilising endograft-position and reducing the rate of endoleaks and reinterventions. The present contribution introduces the method, describes the technique of implantation and presents the first clinical results. Material und Methods: The Nellix system consists of two balloon-expandable stent grafts made of a cobalt-chromium composition, surrounded with ePTFE and the so-called endobags. During the implantation each endobag is filled with a non-biodegradable polymer, sealing the aneurysm lumina including the proximal and distal landing zone. Hence, lumbar arteries will be sealed to reduce the probability of a type II endoleak.

RESULTS

Longterm durability as well as the structural integrity of the Nellix system has been proven over 4 years in sheep experiments. The technical success in a multicentre, prospective registry was 94% without the appearance of severe adverse events (migration, occlusion, secondary endoleak).

CONCLUSION

EVAS is a new and different concept of endovascular AAA repair. Recent clinical data of the Nellix system are promising showing a high technical success rate while the need for secondary intervention is low. Further studies in larger cohorts are needed.

The early phase influence of bone marrow concentrate on metaphyseal bone healing

Bone marrow concentrate (BMC) contains high densities of progenitor cells. Therefore, in critical size defects BMC may have the potency to support bone healing. The aim of this study was to investigate the effect of BMC in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect in mini-pigs. A metaphyseal critical-size bone defect at the proximal tibia of 24 mini-pigs was filled with CPG combined with BMC, CPG solely (control group) or with an autograft. Radiological and histomorphometrical evaluations after 6 weeks (42 days) showed significantly more bone formation in the BMC group in the central area of the defect zone and the cortical defect zone compared to the CPG group. At the same time the resorption rate of CPG increased significantly in the BMC group. Nevertheless, compared to the BMC group the autograft group showed a significantly higher new bone formation radiologically and histomorphometrically. In BMC the count of mononuclear cells was significantly higher compared to the bone marrow aspirate (3.5-fold). The mesenchymal progenitor cell characteristics of the cells in BMC were confirmed by flow cytometry. Cells from BMC created significantly larger colonies of alkaline phosphatase-positive colony forming units (CFU-ALP) (4.4-fold) compared to cells from bone marrow aspirate. Nevertheless, even in the BMC group complete osseous bridging was only detectable in isolated instances of the bone defects. Within the limitations of this study the BMC+CPG composite promotes bone regeneration in the early phase of bone healing significantly better than the isolated application of CPG. However, the addition of BMC does not lead to a solid fusion of the defect in the early phase of bone healing an still does not represent an equal alternative to autologous bone.

Decision-making and techniques in hypogastric artery revascularization

The aim of this article was to describe and discuss the currently available endovascular and open surgical techniques to preserve or occlude the hypogastric artery during aortoiliac aneurysm repair and thus support the process of decision-making in hypogastric artery revascularization.

[Interhospital transfer of severely injured patients in Germany. Evaluation of the DGU trauma register]

BACKGROUND

The TraumaNetzwerk(D) DGU was founded 3 years ago and since then the majority of trauma centers have been registered and organized into regional trauma network services (TNW). Within these networks assessment criteria for transferring patients to higher level hospitals are defined. The purpose of this study was to evaluate the incidence, causes, implications and quality of care for patients with major trauma who were transferred for definitive treatment before implementation of the TraumaNetzwerk(D) DGU in Germany.

PATIENT AND METHODS

The data of 19,035 patients listed in the German Trauma Register of the German Society for Trauma Surgery (DGU, 2002-2007) were analyzed. Patients with an injury severity score (ISS) >9 and a blood pressure documented on admission were included into the study. Data were allocated according to patients where therapy was performed completely in the primary hospital of admission (group I; n=16,033; 84.2%) and patients transferred after primary care from one hospital to another centre for definitive care (group II; n=3,002; 15.8%). Comparative parameters were the pattern and severity of injury, physiological state on admission and clinical outcome.

RESULTS

Mean ISS and percentage of patients with an ISS ≥25 did not differ significantly between groups. Of the patients who were transferred to a higher level trauma centre (group II) 20.7% needed catecholamines on admission, 10.1% were in shock (blood pressure <90 mmHg) and 2.5% of the patients underwent resuscitation in the emergency department. Patients of group II had a considerably longer hospital stay (31.2±35.5 days) than patients of group I (24.8±27.1 days). Furthermore, treatment costs were significantly higher for group II (I: EUR 23,870; II: EUR 26,054).

CONCLUSIONS

A relevant percentage of patients transferred from one hospital to another were hemodynamically and clinically unstable. To what extent the quality of patient transfer and therefore major trauma care is improved by the implementation of regional trauma networks in Germany remains to be seen over the next years.

[Treatment strategy for carpometacarpal fracture dislocation]

Carpometacarpal (CMC) fracture dislocations of the 2nd through 5th ray are rare injuries whose extent is regularly underestimated in the initial radiographic evaluation of the hand. Obtaining a computed tomography scan is imperative due to the radiographic underrepresentation of the full bone and joint injury. Restoration of bone and joint anatomy of the affected region is of paramount import to prevent joint deterioration and loss of hand durability and dexterity. Early surgical intervention can lead to good functional results. Different operative treatment strategies exist with a common approach being Kirschner wire, screw or plate fixation after closed or open fracture reduction and joint relocation.

Technical aspects of EVAR for infrarenal AAA

Technical aspects are crucial for planning and performing successful endovascular repair of abdominal aortic aneurysms (AAA). Planning should be based on high-quality computed tomography angiography scans with a slice thickness of ≤ 1 mm. However, even without a workstation for image postprocessing, important angle estimations can be easily performed. Several devices are available today to treat abdominal aneurysms. In most elective cases all currently available 3rd generation devices perform comparably if minimal requirements are kept in mind. A safe and technically precise implantation requires cooperation with the involved anesthesiologist in order to manage anticoagulation, blood pressure regulation in general and in currently evolving regional anesthesia. Modern endograft implantation involves highly technical resources, for example guide wires or catheters. Beside patient selection, an optimal procedure planning, graft model choice and endovascular skills are mandatory aspects. In the near future, further improvements in device design and deployment mechanism will allow better device alignment, paving the way for an even broader application of endovascular aneurysm repair (EVAR).

[Quality of documentation and care for victims of violence for the example of a trauma surgery emergency department in a major city]

BACKGROUND

People who have become victims of violence have manifold problems. Besides medical diagnostics and therapy, it is necessary to recognise the situation in which these patients have become such victims, to document the consequences of this violence for use in court and to offer further assistance. Victims of violence often contact primarily a trauma ambulance. The optimisation of the medical treatment of the victims is a relevant traumatological topic, which so far has received only very scant attention. Therefore the aim of this study was to evaluate the necessity for an interdisciplinary combination of treatments for the targeted treatment of these victims.

MATERIAL AND METHODS

Using a standardised data card a retrospective data analysis of all out-patients and all in-patients of a trauma centre with regard to the existence of a violent context was carried out for the year 2004. All such cases were included and the data were evaluated descriptively according to age, gender, information about the act of violence, consequences thereof, type and scope of the diagnostic findings, as well as inducements for further measures. In this context we differentiated between "domestic violence" and "public violence".

RESULTS

The data of 7132 patients were evaluated. Altogether 347 victims of violence were identified (among them 109 victims of "public violence", 59 victims of domestic violence, and 179 cases that could not be allocated clearly). This results in a quota of 4.9% of all patients treated. The average age of the victims was 30.6 years. It was striking that in many cases the anamnesis and documentation were rather fragmentary.

CONCLUSION

A very high percentage of victims of violence could be found among the patients needing traumatological treatment. With regard to the fragmentary care there is an enormous need for medical training and interdisciplinary treatment of victims of violence.

Fixed-angle plates in patella fractures - a pilot cadaver study

Objective

Modified anterior tension wiring with K-wires and cannulated lag screws with anterior tension wiring are currently the fixation of choice for patellar fractures. Failure of fixation, migration of the wires, postoperative pain and resulting revision surgery, however, are not uncommon. After preliminary biomechanical testing of a new fixed-angle plate system especially designed for fixation of patella fractures the aim of this study was to evaluate the surgical and anatomical feasibility of implanting such a plate-device at the human patella.

Methods

In six fresh unfixed female cadavers without history of previous fractures around the knee (average age 88.8 years) a bilateral fixed-angle plate fixation of the patella was carried out after previous placement of a transverse central osteotomy. Operative time, intra-operative problems, degree of retropatellar arthritis (following Outerbridge), quality of reduction and existence of any intraarticular screw placement have been raised. In addition, lateral and anteroposterior radiographs of all specimens were made.

Results

Due to the high average age of 88.8 years no patella showed an unimpaired retropatellar articular surface and all were severely osteoporotic, which made a secure fixation of the reduction forceps during surgery difficult. The operation time averaged 49 minutes (range: 36-65). Although in postoperative X-rays the fracture gap between the fragments was still visible, the analysis of the retropatellar surface showed no residual articular step or dehiscence > 0.5 mm. Also in a total of 24 inserted screws not one intraarticular malposition was found. No intraoperative complications were noticed.

Conclusions

Osteosynthesis of a medial third patella fracture with a bilateral fixed-angle plate-device is surgically and anatomically feasible without difficulties. Further studies have to depict whether the bilateral fixed-angle plate-osteosynthesis of the patella displays advantages over the established operative procedures.

Flexor tendon repair using a new suture technique: a comparative in vitro biomechanical study

INTRODUCTION

The purpose of this experimental study was to evaluate the biomechanical characteristics of two new four-strand core suture techniques for flexor tendon repair.

MATERIALS AND METHODS

The two new suture techniques (Marburg 1, Marburg 2) are characterized by four longitudinal stitches which are anchored by a circular or semicircular suture. They were compared with three commonly used core suture techniques (modified Kessler, Tsuge, Bunnell). Fifty porcine flexor tendons were randomly assigned to one of the five core suture techniques. Outcome measures included ultimate tensile strength, maximum of lengthening, mode of failure and 1 mm gap formation force.

RESULTS

The highest ultimate tensile strength was found for the modified Kessler technique (115 N). Both new techniques showed an ultimate load exceeding 50 N (57 N for Marburg 1, 54 N for Marburg 2). The Marburg 1 technique showed the highest gap resistance of all tested suture techniques. The Bunnell and Tsuge core suture techniques produced the poorest mechanical performance.

CONCLUSION

From these experimental results, the new Marburg 1 core suture technique can be considered for flexor tendon repair in a clinical setting with the use of active motion protocols.

Maternal antibodies to rotavirus: could they interfere with live rotavirus vaccines in developing countries?

INTRODUCTION

Past experience with live oral vaccines including licensed rotavirus vaccines demonstrates a trend towards reduced vaccine efficacy in developing countries compared with developed countries. The reasons behind this disparity are not well understood. Transplacental transfer of maternal antibodies and breast milk ingestion may attenuate vaccine responses in infants in developing countries where rotavirus infections are endemic, and maternal antibody levels are high. We examined the prevalence and level of rotavirus antibody in maternal and cord serum, colostrum and breast milk in a developing country setting.

METHODS

100 mother-infant pairs were prospectively recruited from December 2008 to February 2009 at Dr. Sardjito Hospital, Yogyakarta, Indonesia. Maternal and cord sera were collected during delivery. Colostrum and transitional breast milk were collected between day 0-3 and day 7-10 postpartum respectively. Rotavirus-specific IgA and IgG were estimated for all specimens and virus neutralization assays were conducted on a subset of milk specimens.

RESULTS

All maternal and cord serum samples were positive for rotavirus-specific IgG antibodies with a strong correlation between levels of rotavirus-specific IgG in mothers and levels transferred to infants in cord blood (r=0.86; p=0.001). 78% of colostrum and 67% of transitional breast milk specimens were positive for rotavirus-specific IgA. There was a median 4-fold decrease in rotavirus-specific IgA from colostrum to transitional breast milk. Neutralizing antibodies were present in 56% of colostrum specimens assayed (19/34) and in 41% of transitional milk specimens assayed (14/34).

CONCLUSIONS

Maternal serum and breast milk antibodies to rotavirus are highly prevalent in a developing country setting. Evaluation of the impact of maternal anti-rotavirus serum and breast milk antibody upon vaccine immunogenicity would help to inform rotavirus vaccination strategies, especially in developing settings.

The progress of early phase bone healing using porous granules produced from calcium phosphate cement

Objective

Bone grafting is a vital component in many surgical procedures to facilitate the repair of bone defects or fusions. Autologous bone has been the gold standard to date in spite of associated donor-site morbidity and the limited amount of available donor bone. The aim of this study was to investigate the progress of bone regeneration and material degradation of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder compared to the use of autologous bone grafting in the treatment of "critical size defects" on load-bearing long bones of minipigs.

Methods

A critical size defect in the tibial metaphysis of 16 mini-pigs was filled either with autologous cancellous graft or with micro- and macroporous carbonated, apatic calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder. After 6 weeks, the specimens were assessed by X-ray and histological evaluation. The amount of new bone formation was analysed histomorphometrically.

Results

The semi-quantitative analysis of the radiological results showed a complete osseous bridging of the defect in three cases for the autograft group. In the same group five animals showed a beginning, but still incomplete bridging of the defect, whereas in the CPG group just two animals developed this. All other animals of the CPG group showed only a still discontinuous new bone formation. Altogether, radiologically a better osseous bridging was observed in the autograft group compared to the CPG group.

Histomorphometrical analysis after six weeks of healing revealed that the area of new bone was significantly greater in the autograft group concerning the central area of the defect zone (p < 0.001) as well as the cortical defect zone (p < 0.002). All defects showed new bone formation, but only in the autograft group defects regenerated entirely

Conclusions

Within the limits of the present study it could be demonstrated that autologous cancellous grafts lead to a significantly better bone regeneration compared to the application of calcium phosphate granules (CPG) produced from a calcium phosphate self-setting cement powder after 6 weeks. In the early phase of bone-healing, the sole application of CPG appears to be inferior to the autologous cancellous grafts in an in vivo critical size defect on load-bearing long bones of mini-pigs.

[Radial nerve palsy associated with humeral shaft fractures - early exploration or expectant procedure? An analysis concerning current strategies of treatment]

BACKGROUND

With a prevalence from 11.8 to 18% no fracture is as often associated with nerve damage as the humeral shaft fracture. Whether the radial nerve should be surgically explored in association with a palsy in humeral shaft fractures in order to exclude an interposition or discontinuity is being discussed controversially. The aim of this study was to assess the strategies for primary care of radial nerve palsies associated with humeral shaft fractures in Germany.

MATERIAL AND METHODS

In a standardised survey 495 traumatological and 134 neurosurgical clinics were interviewed regarding the treatment of primary radial nerve palsies after humeral shaft fractures. The distribution of the survey included all level-one trauma centres. Statistics were based on the supply strategies, the number of observed contusions, discontinuities and inter-position of the N. radialis in the fracture gap. Moreover, the results were recorded after primary neurorrhaphy.

RESULTS

The evaluable response rate to the questionnaire was 56% (university hospitals 77%, level-one trauma centres 63%, level-two trauma centres 70%, level-three trauma centres 44%). 6097 humeral shaft fractures have been treated per year, the incidence of primary radial nerve palsy was 8.6%. Regarding the management strategies, 59% of the hospitals advocated exploration of the nerve, while 25% reported that the decision depends on the individual case. 16% reject the exploration in case of a primary nerve palsy. In the case of an exploration, contusions (74%) of the nerve were largely seen, followed by nerve interpositions in the fracture gap (19%) and discontinuity (7%). In the case of neurorrhaphy, a partial or complete remission was found in 87% of cases.

DISCUSSION

Although a primary expectant procedure is recommended in the literature due to the high spontaneous remission rate of 90%, an early exploration of the nerve is often preferred in clinical practice. In these cases, the use of an interlocking intramedullary nail as a minimally invasive treatment option does not appear useful due to the direct exposure of the fracture zone and the radial nerve. Interestingly, the feared discontinuity occurs rarely. The impact of nerve interposition in the fracture gap without surgical exploration remains unclear due to the lack of visibility.

CONCLUSION

There is no consensus concerning the treatment of radial nerve palsies after humeral shaft fractures in Germany. Discontinuities are rare, the rate of spontaneous recoveries is high. Whether and when an exploration of the radial nerve is obligatory in primary radial palsy remains unclear and should be clarified by prospective randomised trials.