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Biomedical subjects

P Regazzoni

Publications and source records attributed to P Regazzoni.

At least 19 recordsLinked to original sources

A less invasive anterior intrapelvic approach for the treatment of acetabular fractures and pelvic ring injuries.

BACKGROUND: The ilioinguinal approach by Letournel has fundamentally contributed to the successful treatment of acetabular fractures. Since most of the present complications arise from soft tissue structures in the inguinal part, it would be desirable to avoid the surgical dissection of this region. We have therefore developed a less invasive anterior intrapelvic approach consisting of a suprapubic access combined with the lateral window of the ilioinguinal approach. METHODS: Between January 2000 and October 2002, 14 patients with acetabular fractures and 6 patients with pelvic ring injuries were consecutively operated using our technique. The patients were prospectively followed up clinically and by standard X-rays for 1 year. RESULTS: In 19 patients the technique was successful and only one patient was converted to an ilioinguinal approach due to difficulties in reducing the fracture. Our access allowed good visibility but reduction manoeuvres were sometimes difficult and the development of a new reduction forceps became necessary. Anatomical and satisfactory reduction was achieved in 13 acetabular fractures and 4 pelvic ring injuries. One cutaneous femoris neurapraxy and one superficial infection occurred related to the approach and both resolved with conservative treatment. Clinical outcome at one year was good to excellent in 17 patients (modified Merle d'Aubigné/Postel score). In 3 patients the result was fair to poor for reasons unrelated to the approach. CONCLUSIONS: Our approach permits visualisation of the entire anterior column and pelvic ring without the necessity to dissect the inguinal neurovascular structures. Our preliminary results demonstrate that safe reduction and stable fixation of selected acetabular- and pelvic ring fractures are possible.

Acetabulum↗

[Interdisciplinary emergency room management of trauma patients from the standpoint of coworkers].

INTRODUCTION: The purpose of this study was to examine whether staff questionnaire evaluation is useful for quality control in the emergency room (ER) setting. METHODS: Consecutive anonymous questionnaires (Likert scale 1-5) were filled out by the involved medical staff in all ER trauma cases in a university hospital from July 2002 to December 2003 (analysis of variance, P<0.05). RESULTS: In 171 ER cases, 844 staff members responded. Main criticisms concerned time management or satisfaction with personal ER training (Likert <4). Consultants rated the quality of their training significantly higher than younger doctors, two thirds of consultants vs one third of residents having passed an Advanced Trauma and Life Support course (P<0.001). Depending on responders' professional specialties and whether the situation concerned multiple trauma (Injury Severity Score >15), a significant systematic difference resulted. CONCLUSION: Our standardized staff questionnaire evaluation was revealed to be a discriminative instrument for quality management of trauma cases in the ER. To confirm these findings, correlation with clinical outcome data and further validation of the method are needed.

Attitude of Health Personnel↗

Fixation principles in metaphyseal bone--a patent based review.

Osteoporotic changes start in cancellous bone due to the underlying pathophysiology. Consequently, the metaphyses are at a higher risk of "osteoporotic" fracture than the diaphysis. Furthermore, implant purchase to fix these fractures is also affected by the poor bone quality. In general, researchers and developers have worked on three different approaches to address the problem of fractures to osteoporotic bone: adapted anchoring techniques, improved load distribution as well as transfer with angular stable screws, and augmentation techniques using bone substitutes. A patent-based review was performed to evaluate which ideas were utilized to improve fixation in osteoporotic, metaphyseal bone, especially in the proximal femur, and to analyze whether the concept had entered clinical use. Anchoring devices that are either extramedullary or intramedullary have a long clinical history. However, demanding surgical techniques and complications, especially in poor quality bone, are justification that such implants and their corresponding surgical techniques need to be improved upon. Expanding elements have been evaluated in the laboratory. The results are promising and the potential of this approach has yet to be fully exploited in the clinics. Internal fixators with angular stable screws open the door for many new anchorage ideas and have great potential for further optimization of load distribution and transfer. Augmentation techniques may improve anchorage in osteoporotic bone. However, the properties of bone substitute materials will need to be modified and improved upon in order to meet the demanding requirements. If we summarise the development process and the clinical use of implants to date, we have to clearly state that more factors than simply biomechanical advantage will determine the clinical success of a new fixation principle or a new implant. Instead, fracture treatment of patients with osteoporosis really needs an interdisciplinary approach!

Bone Nails↗

Displaced anterior column acetabular fracture: closed reduction and percutaneous CT-navigated fixation.

The purpose of this study is to demonstrate the feasibility of computer-tomography-navigated closed reduction and percutaneous fixation (CRPF) in a patient with an externally rotated left acetabular fracture. After a follow-up of 18 months the patient was pain-free and had a normal range of motion in both hip joints. Radiologically, the fracture was fully consolidated, remodelled, and there were no signs of osteoarthritis. To our knowledge, CT-navigated CRPF of a rotated acetabular fracture has not been reported before. Further studies regarding the feasibility of the method are warranted.

Acetabulum↗

[Fluoroscopy based surgical navitation vs. mechanical guidance system for percutaneous interventions. A controlled prospective study exemplified by distal locking of intramedullary nails].

The aim of this study was to directly compare mechanically based targetting and surgical navigation when applied for percutaneous osteosynthesis. The distal locking procedure of intramedullary nails was used as the clinical model for a controlled prospective study. A total of 50 patients were included in two groups. In group 1, the distal locking was done with a mechanical aiming device while in group 2 this was done using a fluoroscopy based surgical navigation system. The target parameters were the precision attained, the necessary operation and fluoroscopy times as well as the number and severity of intra-operative problems. The drill-bit failed to pass through the interlocking hole in one patient with mechanical guidance and in two patients with surgical navigation. The average procedure time for distal locking with mechanical guidance was 6.9 minutes compared with 37.6 minutes with surgical navigation. An additional 44 minutes were required before skin incision and after skin closure as setup time for the navigation system. There was no significant difference in the fluoroscopy time or in the number of intra-operative technical problems. Surgical navigation increased the demand for resources but failed to improve the precision of distal locking compared with mechanical guidance. Further clinical studies are required to determine to what degree these results, using a special model, relate to other applications.

Aged↗

Adapting the fluoroscope to image-guided surgery.

Image-guided techniques have been well established in all surgical disciplines for years. To achieve an optimised work flow during image-guided surgery, the surgeon should be able to manipulate the visual feedback and therefore the imaging unit. C-arm fluoroscopy is the imaging modality routinely used for intraoperative imaging in orthopaedic surgery. The C-arm fluoroscope is positioned and handled by a radiographer on vocal commands, which means that the surgeon depends on external help to manipulate the visual feedback and the work flow is not optimised. The MEPUC interface adapts the C-arm fluoroscope to the needs of image-guided orthopaedic procedures. MEPUC is an acronym for Motorised Exact-Positioning Unit for C-arm. In the hardware component of the MEPUC a conventional C-arm fluoroscope is equipped with stepping motors. The software component allows the surgeon to control the motorised movements of the fluoroscope. The MEPUC interface enables the surgeon to position the C-arm fluoroscope independently in the operating room. Further advantages are achievable when the MEPUC interface is combined with surgical navigation, as this combination allows fully automatic reproduction of former projections. Clinical experience with the MEPUC interface suggests that the work flow for intraoperative imaging is improved and personal requirements reduced.

Fluoroscopy↗

[New stabilization techniques for fixation of proximal tibial fractures (LISS/LCP)].

In unstable proximal tibia fractures secondary dislocation due to insufficient buttressing is a well known complication leading to incongruency of the joint and axial deviation of the leg. Double plate osteosynthesis increases stability, however it is not very biological and may be accomplished by wound healing problems. New stabilization techniques such as LISS (Less Invasive Stabilization System) and LCP (Locked Compression Plate) provide angle stability and minimal invasiveness. Therefore stability of fixation is improved and wound-healing problems decrease. Today simple fractures are still fixed with conventional plates and screws, however more complex bicondylar fractures, particularly those with a metaphyseal comminution zone and/or severe soft tissue damage are fixed favorably by the new stabilization techniques.

Adult↗

[Unilateral apophyseal fracture of the superior anterior iliac crest--a case report].

While soccer playing a 19 year old man suffered from acute onset of severe pain in the anterior part of the iliac crest. A CT-scan confirmed the unilateral avulsion of the anterior superior iliac spine. Due to only minimal fragment dislocation and still open apophysis we decided to treat this injury conservatively with crutches and partial weight bearing. There were no complications and already three weeks after the accident the young man was nearly painfree. Avulsion of the anterior superior iliac spine most commonly occur in adolescents. The fracture is often missed and treated as muscle injury or hip pain and therefore received a symptomatical therapy. Later a typical hypertrophic callus formation confirms the avulsion fracture. The avulsion occurs by sudden pull of the sartorius muscle to the anterior superior iliac spine. The pull of the muscle dislocates the loose fragment caudally. In most of the cases a conservative treatment is successful.

Adult↗

[Management of complex distal radius fractures].

Complex injuries of the distal radius can be associated with articular comminution, severe soft tissue injury, large metaphyseal and/or diaphyseal bone defects, carpal ligament tears or its combinations. We recommend a standardized three step approach for the management of these severe injuries: external fixation as an emergency procedure; treatment of soft tissue damage and further diagnostics as needed; definitive adapted operative therapy after thorough analysis of the specific injury.

Bone Plates↗

[Dorsal double plating for fractures of the distal radius--a biomechanical concept and clinical experience].

This article describes the anatomical and biomechanical rationale for stable internal fixation of distal radius fractures using a dorsal approach. The three column biomechanical model is illustrated. Advances in the understanding of the anatomy, the biomechanical model of the three columns and our clinical experience with dorsal double plating have lead to the development of a new set of precontoured 2.4 mm Titanium plates with the option for head locking screws.

Biomechanical Phenomena↗

[Endoscopically controlled stabilization of humerus shaft fractures. The endoscope as an aid in minimally invasive osteosynthesis].

This study describes the anatomical basis of direct visualization of the radial nerve and of fracture reduction in humeral shaft nailing and reports first clinical results. Fourteen cadavers were random selected and dissected in order to determine the exact course of the radial nerve in relationship to anatomical landmarks. In individuals with a total humeral length between 25-33 cm the radial nerve was found to cross the humeral shaft exactly in the middle of the long axis of the humeral shaft. The average distance from the lateral epicondyle to the point were the radial nerve penetrates the lateral intermuscular septum was 11.9 +/- 1.0 cm, the distance from the posterior tip of the acromion to the crossing of the nerve with the medial border of the humeral shaft was 12.9 +/- 1.5 cm. Using these landmarks in six clinical cases fracture reduction, visualization of the radial nerve and intramedullary nailing could be achieved with endoscopic control. There were no surgical complications such as secondary radial nerve palsy, hematomas or wound healing problems. With the use of the endoscope the number of secondary radial nerve palsies associated with intramedullary humeral shaft nailing might be reduced in the future.

Adult↗

[Early functional treatment of surgically managed Achilles tendon rupture].

40 acute traumatic ruptures of the Achilles tendon were evaluated in a prospective study after open repair using an early functional rehabilitation protocol. The age of the patients averaged 43 (23-64) years. The operation consisted of a Kessler suture and microadaptation of the tendon. A special boot was used for after treatment. The boot was used 9 (1-18) weeks and full weight bearing was reported after 7 (1-16) weeks. The sick leave time averaged 5.5 (0-18) weeks. After 1 year, length and ankle joint motion were restored. Outcome was assessed using a 100-point score described by Thermann. After 4 months it averaged 73.5 +/- 15.5 points and after 1 year 94.5 +/- 6.0 points. There were no perioperative complications. One rerupture occurred 6 weeks postoperatively and was operated successfully. The combination of surgical repair and early functional after treatment resulted in normal function after 1 year, but requires cooperation of the patient.

Achilles Tendon↗

[(Impending) pathological fracture].

Pathological fractures will be encountered in increasing frequency due to more patients with cancer, surviving a longer period. The skeleton is the third most frequent localization for metastases. Breast cancer is still the most common primary tumor, but bone metastases from lung cancer seem to be diagnosed more and more. Despite of finding metastases most often in the spinal column, fractures are seen mostly at the femoral site. A pathological fracture and, in almost all cases, an impending fracture are absolute indication for operation. An exact definition of an "impending fracture" is still lacking; it is widely accepted, that 50 per cent of bone mass must be destroyed before visualization in X-ray is possible, thus defining an impending fracture. The score system by Mirels estimates the fracture risk by means of four parameters (localization, per cent of destructed bone mass, type of metastasis, pain). Improving quality of life, relieving pain, preferably with a single operation and a short length of stay are the goals of (operative) treatment. For fractures of the proximal femur, prosthetic replacement, for fractures of the subtrochanteric region or the shaft, intramedullary nails are recommended. Postoperative radiation therapy possibly avoids tumor progression. In patient with a good long term prognosis, tumor should be removed locally aggressive.

Bone Neoplasms↗

Endoscopic-assisted, minimally invasive anterior pelvic ring stabilization: a new technique and case report.

This report describes the technique of endoscopic-assisted reduction and stabilization of the anterior pelvic ring with endoscopic visualization of all critical bone and soft tissue structures. Compared with the conventional ilioinguinal approach of Letournel, the endoscopic technique facilitates a reliable internal fixation of anterior pelvic ring fractures with minimal soft tissue trauma. Thus, the use of the endoscope enables us to apply the concept of minimal invasive plate osteosynthesis to the pelvis. We recommend the described technique for complex anterior pelvic ring fractures, in which the anterior stabilization has to be achieved with a plate from the symphyseal region to the iliac wing.

Adult↗

Volumetric model determination of the tibia based on 2D radiographs using a 2D/3D database.

We present a new concept with mathematical background for the construction of a three-dimensional (3D) volumetric model of the human tibia based on two conventional orthogonal two-dimensional (2D) radiographic images. This approach is supported by a computer database containing a collection of 80 2D/3D image data sets of individual cadaveric tibiae. For each of these tibiae, the database contains digitized 2D orthogonal radiographic images in both anterior and lateral views, and the corresponding 3D CT data obtained by computerized tomography. To obtain a 3D model of a tibia for a given patient, shape matching is performed. The computer finds the most similar tibia to the patient's tibia among the 2D radiographic images in the database by applying a matching process. To improve accuracy, a 2D image warping procedure can be applied on the slices of the selected bone prior to 3D reconstruction. The warping process is controlled by the contour data of the two orthogonal views. We found that the 3D model thus achieved was useful for virtual preoperative planning and for simulation of the internal fixation of long bones.

Cadaver↗

[Technology integration and process management. Concept and implementation of a new platform for simultaneous diagnosis and therapy of acutely ill and injured patients and for elective computer assisted surgery (CAS)].

Modern imaging and computer technology gain more and more importance in surgery. This is true for elective and emergency diagnosis and treatment. However integration of technology and optimization of process management is severely behind. A new diagnostic-therapeutic platform should balance this deficit. The platform is composed of a fully equipped operation room environment with integrated high end computer-tomography with navigation, a digital subtraction angiography and an OR- and imaging-table particularly developed for this set-up. The platform may be used for elective diagnosis, for diagnosis and therapy in polytraumatized patients in one and the same location (one stop shop) and for computer assisted surgery (CAS). Bringing the technology to the patient and not the patient to the technology can save time consuming and potentially dangerous transports and expensive personnel can be reduced. Navigation-technology and high quality intra-operative imaging expand the spectrum of minimally invasive surgery.

Diagnostic Imaging↗

[Computer-assisted surgery: developments and prospects in 2001. Results of a workshop at Schloss Reisenburg, 23-24 November 2000].

The progress in computer assisted surgery (CAS) is influenced by new technologies in imaging as well as by the input of the users. At present, CAS procedures are established in dorsal spine instrumentation, prosthetics and long bone surgery. Present status and future of CAS was a topic of an expert meeting at the Reisensburg castle. Imaging will speed up in the future using multi-detector techniques. C-arm navigation will gain more information using the 3D technology intraoperatively. CT based navigation procedures are standard in spine and will be established in pelvic surgery. CAS in robotics at the moment means the use of robot-assistance. A new concept is the modality-based navigated surgery, which can be used at various skeletal locations. Visualization of patient data will improve using 3D semi-transparencies with real time update. In the future it will be mandatory to find algorithms to fuse the different possibilities and techniques. A new concept of surgical training is necessary to teach CAS procedures. Therefore discussion must go on to improve these systems.

Arthroplasty, Replacement, Knee↗

[LISS tractor. Combination of the "less invasive stabilization system" (LISS) with the AO distractor for distal femur and proximal tibial fractures].

Minimally invasive plate osteosynthesis (MIPO) in conjunction with the less invasive stabilization system (LISS) first requires reduction and retention of the fracture using such aids as external fixation, distractors, and percutaneous reduction clamps before the plate can be applied. Based on the open indirect "biological" technique of osteosynthesis, the LISS was combined with an AO distractor (LISS tractor) integrated into the LISS plate. This made reduction possible against the plate before final fixation of the LISS plate. The LISS tractor concept was validated in three patients and we present the technique here. No malalignments > 5 degrees occurred. Fluoroscopy lasted 3.0 min (range: 2.1-4.5) and the operation 125 min (range: 90-150). Modification of the well-known LISS technique by integrating the distractor into the LISS plate to simplify reduction and to provide temporary retention of the fracture has the potential to reduce the fluoroscopy time, the operation time, the rate of malalignments, and the learning curve for this MIPO technique.

Aged↗