Biomedical subjects

N Haase

Publications and source records attributed to N Haase.

6 recordsLinked to original sources

PubMed2002

[Mobility of unstable fractures of the odontoid during helmet removal. A biomechanical study].

In severe motorcyclist accidents unstable injuries of the cervical spine can usually not be excluded before an X-ray has been taken in the hospital. Despite this the helmet has to be taken off at the place of the accident in order to provide adequate treatment and airway management of the injured driver. There are no data in the current literature showing what happens to unstable lesions of the cervical spine during helmet removal. An experimental unstable lesion of the cervical spine was created by an osteotomy of the odontoid in 10 fresh frozen cadavers with intact soft tissues. All motions occurring in the segments C1-2 and C2-3 during helmet removal were recorded by fluoroscopy. The average motion in the unstable segment C1-2 was 23.7 degrees during a full range of extension-flexion movement of the cervical spine without any signs of dislocation of the segment. After application of the helmet there was one case of dislocation of C1-2 in neutral supine position already, and two further cases of dislocations during helmet removal. The average motion of C1-2 recorded during helmet removal was 19.0 degrees (2-25 degrees ), median 18.0 degrees. In order to avoid fracture dislocations and motion in the unstable upper cervical spine the helmet should better be cut in pieces at the place of the accident. There is a need for discussions with helmet producers to develop a new generation of helmets that can be removed easily without manipulating the head.

Accidents, Traffic↗

PubMed2001

[Spinal epidural hematoma as a sequelae of knife stab injury. A diagnostic problem?].

Spinal epidural hematoma are a rare but serious complication of thoracic stab wounds. Their incidence should always be taken into consideration when first examining the patient, and it is also necessary to be able to find proof in either MRI or CT-scan. In our case the patients diffuse neurologic symptoms connected with a rather unreliable appearing personality made the diagnosis even more difficult. Initially it was possible to show the defect only in MRI.

Adult↗

PubMed2001

[Knee joint endoprosthesis].

Total knee replacement is increasing in number due to increased life expectancy and improved implants. [figure: see text] Degenerative changes (arthritis) and joint destruction based on polyarthritis and posttraumatic deformities are the common indications. There are basically four modes for knee replacement: Unicompartimental prosthesis, non-constrained, semi-constrained (posterior stabilized) and constrained total knee arthroplasty. Of major importance in knee alloarthoplasty are restitution of the correct limb axis, sufficient lateral ligaments and the restoration of the patellofemoral joint. Therefore particularly in cases with deformities an extensive soft tissue release is mandatory. A meticulous operative technique and versatile implants lead to good clinical outcome. Possible complications are still septic and aseptic implant loosening as well as wound infections.

Arthroplasty, Replacement, Knee↗

PubMed2001

[Techniques of extramedullary osteosynthesis in proximal femoral fractures].

Plate osteosynthesis at the proximal femur is possible for intertrochanteric and subtrochanteric femoral fractures. Common implants are the dynamic hip screw (DHS), the dynamic condylar screw (DCS) and the condylar blade plate. The dynamic hip screw is mainly used in introchanteric femoral fractures, whereas the other two devices are suitable for stabilizing subtrochanteric fractures. Those extramedullary implants compete with several intramedullary nailing systems. Because of less soft tissue compromise the nailing systems have been favored by many surgeons during the last decade. This is particularly true for the subtrochanteric area where intramedullary devices offer higher primary stability, allowing initial full weight bearing. A good indication for the extramedullary technique with a two-hole dynamic hip screw is the stable intertrochanteric fracture with an intact lesser trochanter. The other fracture types of the proximal femur in the intertrochanteric and subtrochanteric area are better treated with intramedullary devices. The remaining indications for the dynamic condylar screw and the condylar blade plate are correction osteotomies and some salvage procedures.

Bone Plates↗

PubMed2000

[Dorsal oblique pelvic fixator: development and biomechanical testing].

In haemodynamically unstable patients with an unstable pelvic ring injury the primary stabilisation of the pelvis and thus reduction of pelvic volume is important for the success of the treatment. The pelvic C-clamp is an approved emergency device for these unstable pelvic ring injuries. A secondary procedure though is necessary in most of the cases with a hig rate of wound problems in already traumatized soft tissue areas. The ventrally placed external fixator is a simple and quick procedure with little soft tissue damage. Though primary stability is sufficient even for C-type injuries, biomechanic stability of the posterior pelvic ring is often insufficient for mobilization. Based on biomechanic considerations, a new dorsal oblique pelvic external fixator was developed for pelvic C-type injuries. With the advantages of the supraacetabular fixator and two additional Schanz screws the ventral fixator should stabilize the posterior pelvic ring with comparable stability to the pelvic C-clamp. A primary and already definitive minimal invasive stabilization of the posterior pelvic ring was the aim. In the first series several variations of this asymmetric fixator with two different Schanz screw applications were tested biomechanically. In a second series the favorite version was tested versus the supraacetabular fixator and the pelvic C-clamp. Both of the biomechanic test series were performed with artificial pelves in the one leg stance model in the material testing machine. SI disruption and sacral fracture were the posterior instability types in 6 pelves each. There was no statistically significant difference between the dorsal oblique fixator and the pelvic C-clamp. But the new fixator was significantly more stable than the supraacetabular fixator or the new fixator without pretension.

Biomechanical Phenomena↗

PubMed1985

Predictive value of antepartum fetal heart rate non-stress test in high-risk pregnancy.

For antepartum evaluation of high-risk pregnancies the non-stress test (NST) was performed in order to predict favorable or adverse fetal outcome. Between January 1, 1980 and December 31, 1980, 4078 NSTs were performed on 454 women with high-risk pregnancies. The NSTs were evaluated for pathology by a CTG pathology score. The NST interpretation were normal 95%, slight pathological 4% and severe pathological 1%. The group of women in whom all NST results were normal gave birth to healthy babies. In tact with an increasing number of pathologica-NSTs and with worsening CTG pathology score, a significant increase was found for cesarean section rate, acute operative delivery, low Apgar score, low umbilical cord artery pH and infants born small for gestational age or clinically dysmature. The frequence of perinatal morbidity was almost the same, irrespective of whether the NSTs showed accelarations or not on one or more occasions. To identify fetuses suffering from retarded intra-uterine growth the predictive value of normal NST was 97.3% and the predictive value of pathological NST was 34.8%. To identify perinatal morbidity the predictive values were 87.4% and 55.1% respectively. The NST appears to be a reliable test for antepartum assessment of fetal well-being in high-risk pregnancies.

Female↗