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Biomedical subjects

H Tscherne

Publications and source records attributed to H Tscherne.

At least 109 records · Page 6Linked to original sources
PubMed1997

[Malignant bone tumors].

Owing to advances in adjuvant therapy, the outlook for patients with primary malignant bone tumors has improved dramatically in recent decades. This applies both to improved survival and to increased limb salvage rates. The diagnostic strategies and a staging system for malignant bone tumors are outlined. Technical aspects of the standard limb salvage procedures, such as Tikhoff-Linberg resection at the shoulder, internal hemipelvectomy, proximal and distal femur resection and rotation plasty are presented. The use of soft tissue procedures such as flaps and the use of modular implant systems has reduced the complication rates of limb salvage procedures. In the future we hope to further improve prognosis and quality of life for such patients by the application of risk-adapted strategies for chemotherapy and surgery.

Adolescent↗
PubMed1997

[Long-term results of therapy of open and closed fractures of the elbow joint].

Fractures of the elbow joint are quite rare compared with the total incidence of injuries to the extremities. However, elbow fractures often result in significant disability. Therefore in a retrospective study, we have evaluated criteria that are of prognostic value for late functional outcome. Sixty-four (10.3%) of 622 patients with closed elbow fractures and 107 (89%) of 119 patients with open elbow fractures underwent a physical examination. The mean follow-up time was 8.2 years. The functional outcome was recorded by a modified score (0-max. 15) according to Morrey. Epidemiological data from both groups revealed a greater severity and higher degree of injury in open fractures than in closed fractures. In contrast, both groups presented a comparably good functional result. The most significant factor for poor outcome (score < 5) was identified as nerve lesions. Among all nerve lesions in open fractures, 45% resulted in a functional score of < 5; in 42% of closed fractures combined with a nerve lesion a similarly poor result was also noted. A second major factor appeared to be the method of primary therapy. An external joint transfixation resulted in a score of < 5 in 32% of patients that were treated primarily by transfixation. In cases initially treated with open reduction and internal fixation, only 18.5% of open fractures and 3.1% of closed fractures presented a similar low score. According to our results the late functional outcome of elbow fractures depends less on the type of fracture than on the presence of a nerve lesion and the method of primary treatment, which should facilitate early mobilization.

Elbow Joint↗
PubMed1997

[Treatment outcome after complex pelvic trauma in children].

Between 1972 and 1994 21 children up to 14 years old sustained complex pelvic trauma treated at the Trauma Department of the Hannover Medical School. Sixteen of the 17 survivors were followed at an average of 8.9 years. In 8 patients operative treatment of the disrupted pelvic ring (external or internal fixation) was performed; in 8 patients the treatment was conservative. At follow-up 9 patients (56%) were pain-free; 4 reported slight, 2 moderate and one patient severe pain (at rest). There were no neurological deficits. Four patients had disturbed micturia, and 1 had bowel incontinence. Radiological evaluation showed anatomic reconstruction of the pelvic ring in 9 cases (56%). Residual maximum displacement of 12 mm was detected in 2 patients. In 3 cases osteoarthritis or ancylosis of the SI joint was present. In 3 cases a clinically not disturbing heterotopic ossification was found. Another 2 cases had ossifications of the pubic symphyses. A post-traumatic acetabular dysplasia was detected in 2 cases; a hypoplasia of the hemipelvis was seen in 3 patients. In a retrospective analysis of the primary radiographs, 13 pelvic lesions were not detected during the primary clinical course (sacral fractures, lesions of the triradiate cartilage). Despite this finding the pelvic outcome was rated good and excellent in 10 patients (63%), moderate in 1 patient (hypoplasia of the hemipelvis, and poor in 5 patients (31%) with severe pain or urogenital disturbances. The maximum ratings in social reintegration was given to 9 patients, a medium rating to 7 patients. All patients were socially integrated.

Adolescent↗
PubMed1997

[Bone lengthening osteotomy in malunited clavicular fracture].

Most fractures of the clavicle heal well with nonoperative treatment. On rare occasions, malunited clavicular fractures are associated with a pattern of disability that includes not only pain but also functional or neurovascular impairment. In these cases, clavicular osteotomy and correction of the deformity should be considered. In four patients with a malunited fracture of the clavicle following nonoperative treatment, we performed a clavicular osteotomy for deformity. In all four patients the clavicular fracture healed with shortening associated with pain and ipsilateral glenohumeral dysfunction. The deformity was not associated with neurovascular dysfunction. In preoperative X-ray studies, the shortening of the malunited clavicle was between 0.9 and 2.2 cm in comparison to the contralateral clavicle. All patients underwent an extension osteotomy of the clavicle with interposition of an autogenous iliac crest bone graft. The follow-up was 1-4 years postoperatively. The functional outcome was evaluated using the Constant-Murley and the UCLA score. All patients had immediate pain relief following osteotomy and correction of the deformity. The shoulder function rapidly improved, and the functional outcome was good in three out of the four patients. If there is associated functional impairment in malunited clavicular fractures, extension osteotomy combined with autogenous bone grafting may produce predictably good results.

Adult↗
PubMed1997

[Advantages of the unreamed tibial nail in comparison with external fixator in treatment of grade 3 B open tibial shaft fractures].

Between 1987 and 1993, 41 grade 3B open tibial shaft fractures were treated with the unreamed tibial nail (URTN n = 22) or an external fixator (FIX n = 19). The method of treatment was left to the choice of the operating surgeon. Three below the knee amputations were performed, three patients died, and three were lost to follow-up. In all, 32 patients were followed up to union or at least for 1 year. There were no significant statistical differences between the two groups (P < 0.2, chi-squared, t-test) with respect to fracture type, fracture location, age, gender or accompanying injuries. The URTN group showed significantly better results regarding time to full weight-bearing (URTN 11 +/- 4 weeks; FIX 20 +/- 11 weeks, P < 0.01 M-W) Mann-Whitney Test, number of reoperations (URTN 1.04; FIX 2.89; P < 0.01 M-W), isolated bone grafting (URTN 3/22; FIX 8/19; P < 0.05 chi-squared), and average Karlström and Olerud score (URTN 30 +/- 4; FIX 26 +/- 5; P < 0.05 M-W). In all, 15/17 URTN patients and only 6/15 FIX patients achieved unlimited walking distance (P < 0.01 M-W). Time to bony union, infection, and nonunion were not significantly different between groups.

Adult↗
PubMed1997

[Fractures of the thoracolumbar spine. Late results of dorsal instrumentation and its consequences].

Between January 1989 and July 1992, 76 patients with thoracolumbar fractures were operatively treated at the Department of Trauma Surgery, Hannover Medical School. After a mean of more than 3 years, 56 of 62 patients (90%) still alive who had their implants removed were examined. According to the ASIF classification 33 patients sustained type A fractures, 13 type B and 10 type C. Three patients with incomplete paraplegia returned to normal; in one case of complete paraplegia no change occurred. In 40 cases the dorsal instrumentation was combined with transpedicular cancellous bone grafting. The mean operative time totaled 3 h. In this series, two complications (3.6%) were observed: one iatrogenic vertebral arch fracture without consequences and one deep infection. Compared to the preoperative status, our follow-up examinations demonstrated permanent physical and social sequelae; the percentage of individuals able to do physical labor was reduced by half (22 to 11 patients) whereas the share of unemployed or retired patients doubled (4 to 8 patients). At the time of follow-up examination only 21 of 42 patients continued in sports. The assessment of complaints and functional outcome with the "Hannover Spinal Trauma Score" reflected a significant difference (P < 0.001) between the status before injury (96.6/100 points) and at the time of follow-up (71.4/100 points). The radiographic assessment in the lateral plane (Cobb technique) demonstrated a significant (P < 0.001) mean restoration from an initial angle of -15.6 degrees (kyphosis) to +0.4 degree (lordosis). Serial postoperative radiographic follow-up showed progressive loss of correction; at follow-up examination we found a mean of 10.1 degrees (P < 0.001). Compared to the preoperative deformity a mean improvement of 6.1 degrees to an average of -9.7 degrees at follow-up examination was noted. The addition of transpedicular cancellous bone grafting did not decrease the loss of correction. CT scans after implant removal were performed in 9 cases: only 3 of 9 patients showed evidence of intervertebral fusion. No correlation could be found between ASIF classification and radiographic outcome. However, the preoperative wedge angle of the vertebral body correlated significantly with the postoperative loss of reduction. Due to disappointing results after dorsal stabilization with transpedicular cancellous bone grafting we recommend a combined procedure with dorsal stabilization and ventral fusion in cases of complete or incomplete burst injury of the vertebral body.

Adolescent↗
PubMed1997

[Initial cranial CT for evaluating the prognosis of craniocerebral trauma].

A total of 208 multiple trauma patients with head injury (HI) were investigated who had been treated in the period from 1990 to 1995. The average age was 35.2 +/- 17.7 years; the injury severity according to ISS was 30.2 +/- 8.6 points; 20.5% died as a result of the HI; the mortality of all patients was 26.5%. The Glasgow Coma Scale (GCS) was determined at an average of 22 min after trauma (8.0 +/- 4.3 points) at the scene of accident. The patients were classified according to GCS into minor HI (group 1: 14-15 points), moderate HI (group 2: 9-13 points) and severe HI (group 3: 3-8 points). Patient outcome was assessed by the Glasgow Outcome Scale (GOS) and was classified as good (GOS 4 and 5) and poor (GOS 1, 2 and 3) outcome. At the latest, 2 h after trauma, a CT scan of the head (CCT) was done. The HI groups are compared regarding frequency of types of injury. In all HI groups the fractures of the bony face occurred at the same frequency (36.0-38.9%). The frequency of calotte fractures (Kal-Fx) increased from group 1 (8.0%) to 2 (19.2%) and 3 (25.6%); fractures of the skull base significantly differed between group 1 (16.0%), 2 (7.8%) and 3 (33.4%). Epidural hemorrhage (EDB) appeared only in group 2 (7.8%) and 3 (6.7); subdural hemorrhage was found in group 1 (2.7%), 2 (7.8%) and 3 (10.0%). Subarachnoid hemorrhage (SAB) was significantly more frequently seen, dependent on HI severity, in group 3 (26.7%) compared to group 2 (11.7%) and 1 (8.0%). Intracerebral contusion (ICK) significantly increased from group 1 (12.0%) to 2 (27.3) and 3 (45.6%). Brain swelling (BS) also significantly increased from group 1 (8.0%) to 2 (19.5%) and 3 (49.0%) and lesions of ventricles (VL) from group 1 (2.7%) to 2 (11.7%) and 3 (20.0%). Midline shift (13.4%) and signs of herniation (4.5%) only occurred in group 3. The analysis of correlation/regression and receiver operating characteristics was able to predict 79% of patients' outcome accurately using GCS (r 0.54; P < 0.0001) alone, using CCT (r 0.65; P < 0.0001) 87% were correctly predicted with significant variables Cal-Fx, EDB, SAB and BS. CCT with GCS (r 0.74; P < 0.0001) were able to predict 88% accurately with significant variables Cal-Fx, EDB, BS and GCS. The combination of CCT with GCS, age and ISS (r 0.78; P < 0.0001) was able to predict only 87% correctly, although the r value was the highest; significant variable were Kal-Fx, EDB, BS, VL, GCS, age and ISS.

Adolescent↗
PubMed1997

[New developments in joint surgery].

The treatment of joint injuries has seen a marked development in the last years. The surgical trauma of articular reconstruction was reduced and our deeper understanding of the mechanism of connective tissue healing influenced the rehabilitation program after joint injuries significantly. Indirect soft-tissue sparing reduction techniques can be applied to most joint fractures and improved fixation techniques using intraoperative fluoroscopy or arthroscopy allow to avoid vast exposures of the joint. The process of ligament healing requires joint movement and a certain stress to the healing tissue in order to achieve optimum scar strength, stiffness and remodeling. Immobilisation thus should be avoided completely after ligament injuries and certain lesions can be treated non-operatively with a high success rate (MCL rupture, ankle sprain, elbow dislocation). In other injuries, surgery should stabilize the joint thus allowing functional rehabilitation (cruciate ligament tears, shoulder dislocation).

External Fixators↗
PubMed1997

[Complex knee joint trauma].

Juxta- and intraarticular fractures of the knee (floating knee), intraarticular fractures with severe soft tissue damage and knee dislocations with vascular or soft tissue lesions are defined as complex knee trauma. A specific management protocol is required for these cases. Fractures should be treated with soft-tissue sparing minimal invasive reduction and fixation techniques to reduce the significant complication rate which is presently encountered. Percutaneous plate fixation, percutaneous screw osteosynthesis and hybrid fixation should be widely used in these cases. In knee dislocation, the central pivot with the two cruciate ligaments should be reconstructed using augmented repair or primary tendon grafting in every case, whereas the treatment of collateral ligament lesions depends on the specific injury type.

Adult↗
PubMed1997

[Pre-bending and and tension adjustment of narrow 4.5 mm AO titanium LC-DCP (limited contact dynamic compression plate)].

UNLABELLED: To assess the behavior of the LC-DCP with prebending and pretensioning we tested: gap angle vs. tensioning force without prebending; Bending moment for different prebending angles; In a model using a fiber tube to simulate the bone for different prebending angles and pretensioning forces of the LC-DCP the deformation in 4 point bending open was tested. Maximum prebending angle was 24 degrees, maximum pretensioning force was 2400 N; in human cadaver tibiae angles of 3 degrees, 9 degrees, 24 degrees and forces of 300 N, 1000 N and 1500 N, were tested to look for the difference in a less idealized model. RESULTS: 1. A near linear curve for gap angle vs. force with an angle of 0.45 degree/100 N was found between 100 N and 1500 N; 2. We did not find a near linear bending moment/bending angle curve up to 8 degrees like in the DCP but an exponential curve development as it had to be expected by the lower modulus of elasticity of titanium; 3. the maximum mechanical stability was found for a angle of 24 degrees and a force of 1500 N. The titanium LC-DCP shows a different mechanical reaction to prebending and pretensioning in the bone implant complex compared to stul DCP. Optimum prebending and pretensioning for axial compression and mechanical stability in the LC-DCP are by far greater than clinically possible. From our mechanical testing a prebending angle of 24 degrees and a pretensioning force of 1500 N would allow the largest axial compression and show the most resistance against deformation in bending open. In the clinical setting this would result in difficult reduction and therefore, we recommend a prebending angle of 9 degrees and a pretensioning force of 1000 N.

Biomechanical Phenomena↗
PubMed1997

Minimally invasive plate osteosynthesis and vascularity: preliminary results of a cadaver injection study.

A cadaver arterial injection study was performed to analyse the vascular supply to the femur and to study the effects of two surgical plating techniques on femoral vascularity. A 16-hole LC-DCP was applied on the intact femora of five fresh human cadavers. On one side, the plate was inserted using a conventional lateral plate osteosynthesis (CLPO) technique with elevation of the vastus lateralis muscle to expose the shaft. On the contralateral side, the plate was inserted percutaneously beneath the muscle using a minimally invasive plate osteosynthesis (MIPO) technique. After plating, blue silicone dye was injected through the common femoral artery. Cadaveric dissection was then performed to identify the femoral perforating arteries (PAs) and the nutrient artery (NA) of the femur. The pattern of periosteal filling and medullary perfusion of the injected dye was analysed and the topography of the PAs and NA was determined. CLPO placed the PAs and NA of the femur at risk. MIPO maintained the integrity of the PAs and NA and was associated with superior periosteal and medullary perfusion. The results of this study indicate that MIPO is superior to the CLPO in maintaining arterial femoral vascularity and perfusion.

Aged↗
PubMed1997

Minimally invasive percutaneous plate osteosynthesis (MIPPO) using the DCS in proximal and distal femoral fractures.

In a prospective study, 14 cases of supracondylar or subtrochanteric fractures or osteotomies were stabilized with a dynamic condylar screw (DCS) inserted using a minimally invasive percutaneous plate osteosynthesis (MIPPO) technique. The technique consisted of 4 major steps: 1) placement of the guide wire under fluoroscopic control and condylar screw insertion through a stab incision; 2) plate insertion beneath the vastus lateral muscle; 3) engagement of the condylar screw to the plate using a modified T-handle and, 4) plate fixation to the shaft using percutaneously inserted self-cutting screws. Between October 1994 and December 1995, 14 cases in 12 patients met the inclusion criteria. There were 11 acute fractures (6 subtrochanteric, 5 supracondylar) and 3 corrective osteotomies. Nine fractures were closed, and 2 were open. One 97-year-old patient died 6 weeks after trauma. There were no infections and 12 of 13 cases healed without a second procedure. There was 1 implant failure (plate screw breakage), which required repeat fracture fixation. At follow-up, there were 2 varus deformities above 5 degrees, 2 shortenings over 20 mm, and 1 rotational deformity of 20 degrees. According to the Neer score, there were 6 excellent, 1 satisfactory, 3 unsatisfactory results and no failures. The results of this technique compare favourably with those of other series of osteosynthesis of subtrochanteric or supracondylar femoral fractures treated with internal fixation without the added morbidity associated with an extensive approach or autogenous bone grafting. However, the surgical technique is demanding, and care must be taken to restore the axial alignment.

Adult↗
PubMed1997

Transarticular joint reconstruction and indirect plate osteosynthesis for complex distal supracondylar femoral fractures.

In a prospective study conducted between 1992 and 1995, displaced Müller type C2-C3 intraarticular fractures of the distal femur were treated using an indirect plate fixation technique and a lateral parapatellar arthrotomy for the direct reduction of the condylar block. There were 6 closed, and 2 open fractures (1 grade II and 1 grade IIIB). Following reconstruction of the articular block, the block was indirectly reduced and fixed to the shaft by a plate inserted by the retrograde method beneath the vastus lateralis. Transcutaneous/transmuscular screws were used to fix the plate to the shaft. Time to bone healing was 12 weeks (median range 8-17 weeks) after surgery without needing primary or secondary bone grafts. There were no infections or refractures. Except for one case which required a corrective osteotomy for 10 degrees of varus malalignment, there were no revisions. According to the Neer score, there were 6 excellent or satisfactory results, 2 unsatisfactory results, and no failures. At follow-up, there were 2 varus-valgus deformities greater than 5 degrees, 2 leg length discrepancies greater than 10 mm, and 2 rotational deformities of 15 degrees. The treatment results for complex supracondylar/intracondylar fractures of the distal femur obtained with this technique compare favourably with other reported series using different techniques without the added morbidity associated with autogenous bone grafting. However, the surgical technique is demanding and special care must be taken to ensure correct axial alignment.

Adult↗
PubMed1997

The deformation of small diameter solid tibial nails with unreamed intramedullary insertion.

'Radiation-independent' aiming systems for the placement of interlocking screws in intramedullary tibial nails have failed because of insertional related nail deformation. Prior to the development of these distal aiming systems, the variable position of the nails' interlocking holes after insertion must be known. In this study, the amount and direction of implant deformation of solid stainless-steel tibial nails (diameters of 8 and 9 mm, n = 20) were analyzed. Measurement of implant deflection (three translations, three angles) in the center of distal transverse locking hole was performed with a three-dimensional-magnetic motion tracker system after nail insertion in paired human cadaver tibiae. The results showed combined mean lateral translation of the 8 and 9 mm nails (n = 20) of -4.5 +/- 3.5 mm (range: 14.3 mm) and dorsal translation -7.8 +/- 5.8 mm (range: 19.2 mm). The combined mean rotational deformation about the longitudinal axis of the nail was 0.3 +/- 0.7 degree (range: 2.4 degrees). The authors conclude that a simple aiming arm, mounted on the proximal nail end alone, is not sufficient to provide accurate distal aiming.

Bone Nails↗
PubMed1997

In vitro and in vivo radiomorphometric analyses of distal screw hole position of the solid tibial nail following insertion.

OBJECTIVE: The objective of this study was to analyse the position of the distal interlocking holes of an unreamed solid tibial nail relative to the adjacent cortices of the tibial bone. DESIGN. IN VITRO: and in vivo radiographic-morphometric analysis. BACKGROUND: To date, 'radiation-independent' intramedullary distal interlocking aiming systems have not been successful, primarily because proximally mounted aiming devices cannot account for the deformation of the nail during insertion; therefore the distal interlocking holes relative to the adjacent cortices must be understood. METHODS: A two-dimensional radiographic-morphometric analysis was performed in 40 tibiae after in vitro (n = 20) and in vivo (n = 20) implantation of unslotted stainless steel unreamed 8- and 9-mm diameter intramedullary nails. RESULTS: The combined in vitro and in vivo results showed average distances between the upper distal transverse hole and the anterior aspect of the tibia of 12.3 mm (SD 1.7 mm; variance 2.9 mm(2); range 7.6 mm). CONCLUSIONS: The distances between the upper distal transverse hole and the anterior aspect of the tibia are the most reliable parameters of distal nail hole position. RELEVANCE: For a 'radiation-independent' distal interlocking aiming system for unreamed intramedullary tibial nails to be successful, it could take advantage of the relatively constant distance between the anterior cortex and the most proximal distal screw hole.

Journal Article↗