Agrin binding to alpha-dystroglycan. Domains of agrin necessary to induce acetylcholine receptor clustering are overlapping but not identical to the alpha-dystroglycan-binding region

The synaptic basal membrane protein agrin initiates the aggregation of acetylcholine receptors at the postsynaptic membrane of the developing neuromuscular junction. Recently, alpha-dystroglycan was found to be a major agrin-binding protein on the muscle cell surface and was therefore considered a candidate agrin receptor. Employing different truncation fragments of agrin, we determined regions of the protein involved in binding to alpha-dystroglycan and to heparin, an inhibitor of alpha-dystroglycan binding. Deletion of a 15-kDa fragment from the C terminus of agrin had no effect on its binding to alpha-dystroglycan from rabbit muscle membranes, even though this deletion completely abolishes its acetylcholine receptor aggregating activity. Conversely, deletion of a central region does not affect agrin's clustering activity, but reduced its affinity for alpha-dystroglycan. Combination of these two deletions resulted in a fragment of approximately 35 kDa that weakly bound to alpha-dystroglycan, but displayed no clustering activity. All of these fragments bound to heparin with high affinity. Thus, alpha-dystroglycan does not show the binding specificity expected for an agrin receptor. Our data suggest the existence of an additional component on the muscle cell surface that generates the observed ligand specificity.

Low-energy extracorporal shock wave therapy for persistent tennis elbow

Fifty patients who suffered from persistent tennis elbow for more than 12 months, and were referred for surgical treatment, were assigned at random to 2 groups of low-energy extracorporal shock wave therapy. Group I received a total of 3000 impulses of 0.08 mJ/mm2; group II (controls) 30 impulses of 0.08 mJ/mm2. Follow up was after 3 and 12 weeks. We found no significant differences between the 2 groups before treatment, there was but significant relief of pain and improvement of function in group I with good or excellent outcome in 56% at the last evaluation.

[Extracorporeal shockwave therapy of radiohumeral epicondylopathy-- an alternative treatment concept]

During the last 2 years 75 patients referred to our hospital for operation of a persistent tennis elbow were followed prospectively after receiving low-energetic extracorporal shock wave therapy. 3 times in weekly intervals all patients received 1000 impulses of the energy density 0.06 mJ/mm2. Follow-ups were performed at 3, 6, 12, 24 weeks. Statistical analysis showed significant improvement both of subjective and objective criteria. 41 patients became painfree. Only 7 patients decided to have an operation after the 24-weeks-follow-up. Ambulatory shock wave therapy is a considerable alternative before surgical intervention in chronic tennis elbow.

Low-energy extracorporeal shock wave therapy for painful heel: a prospective controlled single-blind study

The aim of this prospective single-blind pilot study was to explore the pain-alleviating effect of low-energy extracorporeal shock wave therapy (ESWT) in painful heel associated with inferior calcaneal spurs. Thirty patients who suffered from persistent symptoms for more than 12 months qualified for low-energy ESWT and were assigned at random to two groups, real or simulated ESWT. Before beginning the treatment, any other therapy was stopped for a period of 6 weeks. The shock waves were applied by a experimental device allowing exact localization through an integrated fluoroscopy unit. Patients were treated three times at weekly intervals. Each time 1000 impulses of 0.06 mJ/mm2 were given around the heel spur. Follow-ups were done after 3, 6, 12 and 24 weeks. Patients of the placebo group who did not improve at the 6-week follow-up were then offered ESWT therapy and were checked at 3, 6, 12 and 24 weeks after the last treatment. Whereas we noticed no significant differences between the groups before ESWT, there was a significant alleviation of pain and improvement of function at all follow-ups in the treatment group.

[Treatment concepts of femoral fractures after total endoprosthetic replacement of the hip or knee joint: intra- or extramedullary stabilization?]

A comparison between intramedullary (n = 13) and extramedullary (n = 37) stabilization was performed in 50 patients (mean age 67.4 years) after fractures of the femoral shaft following knee or hip arthroplasty. Fracture of the femoral shaft (mean 5.5 years after the implantation) is observed especially often in patients with osteoporosis, loosening of the prosthesis, and rheumatoid arthritis. The ratio between cemented and uncemented endoprosthesis was 4:1. The investigation shows that extramedullary stabilization by means of plates and screws is the preferred treatment for younger patients and in the case of distal fractures, while in older people intramedullary fixation in combination with an additional osteosynthesis allows early mobilization. The number of complications observed is higher than with primary arthroplasty. The frequency of further operations, postoperative fractures and unsatisfactory results is significantly higher than in primary hip and knee surgery or uncomplicated fracture of the femur.

Proliferation enhancement by spontaneous multiplication of chromosome 7 in rheumatic synovial cells in vitro

Mosaic trisomy of chromosome 7 is known to occur in a variety of non-neoplastic hyperproliferative disorders. In long-term cell cultures established from rheumatic synovium with mosaic trisomy 7, we observed a continuous increase in the proportion of cells with trisomy 7 to over 50% by the 10th in vitro passage. Simultaneous in situ hybridization with a repetitive chromosome-7-specific DNA probe and fluorescent Ki-67 labelling showed a strong correlation between trisomy 7 and an elevated proliferation index in cultured rheumatic synovial cells. Moreover, we observed a fraction of rapidly proliferating cells with up to eight copies of chromosome 7 as the sole cytogenetic change. Frequent somatic pairing of centromeres of two chromosomes 7 in interphase nuclei suggests either atypical non-disjunction with a persisting centromere or selective endoreduplication of chromosome 7.

Extracorporal shock wave therapy for calcifying tendinitis of the shoulder

During the past 2 years, 40 patients referred to the authors' hospital for persistent calcifying tendinitis of the shoulder were seen on prospective followup after undergoing a single extracorporal shock wave therapy. During a single therapy session, all patients received 1500 impulses of the energy density 0.28 mJ/mm2 in plexus anesthesia. Followup examinations were done at 6 and 24 weeks. In 62.5% of the patients partial or complete disintegration of the deposit was observed. Statistical analysis showed significant improvement both of subjective and objective criteria. According to the Constant score, 60% of the patients reached normal values, and 72.5% of the patients had no or only occasional discomfort. Only 6 patients (15%) reported no improvement at the 24-week followup.

Clinical efficacy of pedicle instrumentation and posterolateral fusion in the symptomatic degenerative lumbar spine

Eighty-five patients with degenerative lumbar spine disease and radiologic evidence of instability, all older than 50 years (mean age 63.4 years), underwent transpedicular lumbar CD-spondylodesis and posterolateral fusion between 1987 and 1992; 30 of them (mean age 60.8 years) had posterior lumbar interbody fusion (PLIF) additionally. The patients were followed up for a mean period of 32 months. Of these patients, 86% improved with respect to their pain symptoms, but only 46% showed a good to excellent overall result. Patients with fair and poor outcomes had had significantly more operations on the lumbar spine (P < 0.001), had a greater extent of preoperative lumbar kyphosis (P < 0.05), had a larger preoperative motor weakness (P < 0.05), and had less vertebral slips (P < 0.01) than patients with good to excellent outcomes. Patients treated with transpedicular spondylodesis plus PLIF did not make any better progress than those with transpedicular fusion alone. By the 6-month follow-up a significant difference in the clinical outcome was already apparent (P < 0.001), making an improvement of a then fair or poor result unlikely.

[Multi-segment ventral stabilization of the lumbar spine: a comparative biomechanical study]

The stability provided by three anterior spinal fixation devices (VDS, TSRH, CDH) designed for multisegmental instrumentation have been studied in an in-vitro model using L1-L5 sections of six human cadaveric spines for each instrumentation. Three-dimensional measurement of rotation and translation for the intact and instrumented spine under physiological loads in flexion/extension, lateral bending, and axial rotation were determined. After measuring the intact spine the destabilization was performed by complete intersection of the intervertebral disc, all spines were instrumented for 3 segments. TSRH was found to be significantly (p < 0.05) higher in stiffness in flexion/extension and torsion than VDS. In bending there was no statistical difference. In all tests CDH was significantly more stable than VDS. In flexion/extension it proved higher in stiffness than TSRH, no statistical difference was observed in bending and rotation.

[CDH--preliminary report on a primary stable ventral lumbar spine instrumentation]

CDH-instrumentation was developed by the principles of an improved stability in ventral operation procedure and by the possibility of treating all anterior spinal diseases. The implantation of anterior plates and drawers, the use of rods fixed within the implant in non-parallel directions thus automatically providing for a locking mechanism against displacements, the prevention of dislocation of the cancellous bone screws and the DDT-principle were further requirements. The spine can be corrected according to the three-dimensional anatomy by distraction-, compression and rotational forces, a postoperative external support is unnecessary. After the application of the method in 50 patients (mono- and multisegmental) the excellent stability could be proved.

[Transpedicular lumbar spondylodesis in elderly patients]

70 patients older than 50 years (mean age: 60.2 years) underwent a CD-spondylodesis from 1987 to 1991 for degenerative changes of the lumbar spine, and were followed for 2 years. 88.2% improved, but only 47.1% showed a good-to-excellent result. Patients with fair and poor outcomes had had significantly more operations on the lumbar spine (p < 0.001), had a greater extent of preoperative lumbar kyphosis (p < 0.05), motor weakness (p < 0.05), had less vertebral slips (p < 0.01), had less posterior distraction postoperatively (p < 0.001), and had a greater extent of postoperative motor weakness compared to patients with good-to-excellent outcomes. Age, sex, duration of back/leg pain, taking of analgetic drugs, preoperative pain status, profession, range of walking, time of operation, number of fused segments, blood loss, blood transfusion, postoperative profile of the spine did not show any significant influence upon clinical results. Already at 6-months-follow-up there was significant difference of the clinical outcome (p < 0.001), making improvement of a then fair or poor result unlikely.

[Diagnosis and therapy of osteoid osteoma of the vertebral lamina--a literature review and personal experiences]

Osteoid-osteoma is a benign tumor which is rarely situated in the spine. Five patients with osteoid-osteoma of the lamina treated surgically at the Department of Orthopaedic Surgery of the University of Mainz between november 1990 and january 1992 are reviewed. The combination of pain, painful reactive scoliotic position of the spine or torticollis, hot spot in scintigraphy and nidus in computer tomography is the typical feature of the tumor. The average delay between the onset of symptoms and definitive diagnosis was 10 months. In all cases the tumor was completely removed. In one case with localization in the axis in a 15 year old boy a laminoplastic was performed. The average follow-up was 16 months. Surgical treatment afforded immediate relief of pain and an early return to full spinal mobility. In case of persisting backache especially in children or young adults osteoid-osteoma of the spine must be suspected. The scintigraphy represents the most sensitive method of diagnosis in the early stage.

[Multi-segmental fusion of scoliosis in Duchenne's muscular dystrophy]

Operations in scoliosis in patients suffering from an advanced stage of Duchenne muscular dystrophy are associated with a higher risk due to the extent of the curves, the respiratory insufficiency and frequent cardiomyopathia. Progressive scolioses in 20 wheelchair patients with an age between 10.5-18.3 years (mean 14.6 years) were treated by CDI. The mean preoperative angle in this group was 70.6 degrees, the postoperative angle 31.2 degrees (mean correction 39.4 degrees or 55.8%). The preoperative lordosis of the lumbar spine (mean angle 4.1 degrees) was corrected to 17.8 degrees postoperatively. The average intraoperative blood loss (2300 ccm) was evident more compared with idiopathic scoliosis. One neurologic complication (postoperative disturbance of bladder function) was observed. Nowadays early surgical correction and stabilization (Cobb angle > 20 degrees) has to be recommended as the treatment of choice for scolioses in Duchenne muscular dystrophy using multisegmental instrumentation methods to enable rapid mobilisation and a postoperative care without brace or cast. This conception allows a prophylactic operation including the following targets: prolongation of life expectancy, improvement of sitting position and prevention of rapid deterioration of lung function including assisted mechanical ventilation in late stages.

[Significance of the intervertebral disk in failed reduction of surgically stabilized fractures of the truncal spine]

In 112 patients with a traumatic fracture of the thoraco-lumbar spine operatively treated with different dorsal stabilization techniques from 1983 to 1988, the frontal and sagittal planes of the spine were analyzed over a follow-up period of 5 years. In 14 cases Harrington instrumentation was used, in 81 cases, transpedicular plates, and in 17 cases, a fixateur interne. With regard to the frontal plane the overall loss of correction was 2.3 degrees: with Harrington stabilization 0.7 degrees, with fixateur interne 2.6 degrees, and with plate fixation 3.7 degrees. In the sagittal plane the height of the damaged spinal segment and the kyphotic angulation were determined. The mean height loss after operative repositioning was 12%. With Harrington stabilization it was 16%, with plate fixation 12%, and with fixateur interne 9%. Kyphosis of 9.6 degrees was determined before surgery, and 0.9 degrees after. The angle subsequently deteriorated, reaching 12.6 degrees by the end of 5 years. The loss of correction was 9.3 degrees in the fixateur interne group, 10.9 degrees in the Harrington stabilization group, and 15 degrees in patients in whom plate fixation had been performed. The cause of deterioration was destruction of the invertebral disc in 66% of cases, and angulation of the fractured vertebral body in only 33%. Only in the first 2 years after operation was loss of reposition in the vertebral body observed. In conclusion, stabilization should be complemented by removal of the damaged adjacent disc and intercorporeal autogenous bone grafting from the dorsal or ventral approach.

Prognostic criteria of discogenic paresis

This discourse is aimed at elucidating prognostic criteria for the assessment of the course of a paresis in the case of lumbar disc herniation. Fourhundred and fifty patients were examined who had been operated on for lumbar disc herniation at the Orthopaedic University Clinic Mainz between 1986 and 1991. Of these, 240 showed radicular paralytic symptoms. They were examined prior to the operation, immediately afterwards and 1 year after the operation. The influence of the degree of intensity of the paresis, the time elapsed since the occurrence and other factors like nerve root affected, intraoperative findings, age, sex and weight of the patient were registered. It is obvious that the degree of intensity of a paresis is a good prognostic criterion for the assessment of the postoperative course. A paresis classified as grade III or IV receded in more than 70% of the cases within 6 months. For a paresis of grade II, the recovery rate was 40%. In the case of a total paresis, no complete neurological recovery was registered. The period of time which had elapsed since the occurrence of the paresis, the weight of the patient, the nerve root affected and other factors did not show any significant influence. As a criterion for an emergency or postponed operation on a herniated disc, the duration of paralytic symptoms should therefore be attributed less importance than the progression.

[Natural course in idiopathic scoliosis]

We still do not know enough about the natural course of untreated idiopathic scoliosis although more knowledge would be desirable from the point of view of deciding on adequate conservative treatment or operative therapy. We present the natural course of 110 cases of marked scoliosis and 135 cases of slight, untreated scoliosis with respect to age, sex and localization of the curve. The results are compared to those of other authors.

[The surgical treatment of scoliosis of various etiology. Results after 150 operations using CD-instrumentation with reference to the effects of the instrumentation on the sagittal spinal profile]

At the Orthopaedic University Hospital of Mainz more than 150 patients were treated surgically according to Cotrel and Dubousset procedure. By means of this operation average corrections of the curves of 54.8% to 64.6% could be achieved in the first 150 patients, depending of the localization of the curve. Operative procedure, duration of operation and blood loss are adequate to known procedures, the stability of the method is better than in other known methods. The change of the postoperative sagittal profile demonstrates the influence of the operation in cases of hypokyphosis in the thoracic and hypolordosis in the lumbar spine.

Operative management of epidural tumors of the spine

Seventy-two patients with neoplastic involvement of the vertebral column were operated on between 1986 and 1991. In the course of 79 operations anterior decompression and stabilization alone were performed in 3 cases, while ventrodorsal spondylodesis was carried out in 10 individuals. The remainder of the patients underwent exclusively dorsal decompression and stabilization, mainly with the Cotrel-Dubousset instrumentation (CDI). No external spinal support was required following posterior fixation by CDI alone or in combination with ventral spondylodesis. Forty patients suffered from neurological deficits preoperatively, 20 of them being unable to walk, in most cases owing to severe vertebral collapse. Neurologic symptoms improved in 18 patients postoperatively. Median postoperative survival time averaged 11.5 months. In palliative surgery of the spine, posterior decompression and fixation using CDI permit most patients to retain ambulation without requiring external orthotics. The rate of postoperative complications is reduced by the introduction of CDI.

Metastatic instability at the proximal end of the femur. Comparison of endoprosthetic replacement and plate osteosynthesis

A retrospective study was performed of the surgical treatment of metastatic lesions of the proximal femur in 50 patients. In 25 consecutive cases a megaprosthesis was implanted; compound plate osteosynthesis was performed in another 25 consecutive patients. Indications for surgical treatment were pathological fractures or, for prophylactic treatment, lesions of the femoral cortex exceeding 2.5 cm in diameter or affecting half the diameter of the bone or more. In all patients capable of walking preoperatively mobility was regained. Immediate full weight-bearing stability was obtained in all patients. Group analysis showed that the functional rating of the hip joint was unchanged, i.e., good or excellent, in all patients with compound osteosynthesis, compared to only 68% in the endoprosthesis group. Pain relief was excellent or good in 84% and 88% respectively. Dislocation of the tumor prosthesis occurred in 3 patients. Closed reduction was possible in 2 cases. Local recurrence was higher in the patients undergoing plate osteosynthesis, as was the frequency of tumor-related implant failure. Postoperative survival averaged 14.7 months and 12.1 months respectively.

Metastatic spinal cord compression--options for surgical treatment

Fourty-three cases with metastatic spinal cord compression were reviewed post-operatively to clarify the usefulness of the procedures concerning restoration of neurological function, and pain relief. Only patients with pathological spinal instability and neurological sequelae were included. Posterior decompression and stabilization was performed in all but six patients. All but four patients (91%) reported decrease of pain symptoms. Amelioration of neurological function was achieved in 58%. Re-establishment of walking ability was obtained in 57%. Post-surgery life expectancy averaged 11 months. In patients with widespread metastatic disease and/or multi-level instability of the spine restriction to palliative dorsal procedures is sensible. Post-operative ancillary treatment is necessary.

[Use of the tumor prosthesis in secondary neoplastic destruction of the proximal end of the femur]

Total hip arthroplasty was performed with PMMA-augmented tumor prostheses in 42 individuals suffering from metastatic destruction of the proximal end of the femur at the Orthopedic University Hospital Mainz from 1980 to 1992. Neoplastic lesions had been triggered by carcinomas of the breast in 25 female patients. 24 of our patients presented with pathologic fractures. In all patients capable of walking preoperatively early mobilization could be attained by total hip arthroplasty. Pain relief was achieved in each patient. Resection of the major trochanter and, partially, of the pelvitrochanteric muscle sleeve entailed luxation of the prosthesis six times in 5 individuals during the first postoperative two months; closed reduction was practicable in all of them. Postoperative survival time amounted to an average of 10.5 months. Leg length and hip function were successfully re-established by implanting tumor prostheses after resection of the proximal part of the femur.

Decompression/stabilization of the metastatic spine. Cotrel-Dubousset-Instrumentation in 50 patients

50 patients with metastatic disease of the spine underwent dorsal decompression and stabilization with the Cotrel-Dubousset-Instrumentation from 1987 to 1991. Indications for surgical treatment were neurologic deficit, spinal instability, and/or pain resistant to medical or radiation treatment. No external orthotics were used postoperatively. Pain was relieved dramatically in 45 patients. Among 25 patients suffering from neurologic deficit preoperatively, 13 improved, 15 remained unchanged, whereas 2 developed an incomplete, transient paraplegia. 15 (7) patients were alive after 1 (2) years. Postoperative complications were frequent, but there were only 2 failures of the stabilization device requiring reoperation.

The operative treatment of spinal deformities in MMC

The results of the operative treatment of scoliosis in 12 patients with MMC and in two patients with associated severe kyphosis are presented. In scoliosis only multi-segmental methods combined with ventral procedures allow a postoperative care without brace or cast. The angle before and after operation with the CDI or CDI/VDS procedures averaged 80.3 degrees and 38.2 degrees respectively (mean corrections of 41.5 degrees and 51.6%). The results show that patients with scoliosis with MMC had a approximately 30% greater preoperative angle than patients with idiopathic scoliosis. An early operation (in progressive curves with more than 30 degrees) may reduce the number and severity of complications.

Development of scoliosis in myelomeningocele. Differences in the history caused by idiopathic pattern

The natural history of scoliosis in the literature concerning the idiopathic and neuromuscular scoliosis in myelomeningocele patients (MMC) are compared to our own results in 12 patients with MMC and 89 patients operated because of an idiopathic scoliosis. According to known experiences the natural history of scoliosis in MMC is progression even after the end of growth. The chance of developing a scoliosis increases with the patients, age and the level of the lesion. The higher the level of paralysis the more common is a spinal deformity. In literature the progression rate of MMC scoliosis is 2.5-3.5 degrees per year, with the idiopathic pattern 0.5-0.65 degrees per year after end of growth. Our own results of surgically treated patients show a rate of progression of 6.2 degrees per year in MMC. The surgical treatment must start before a severe spinal deformity has developed because of the higher rate of operative complications.

[Indications and results of surgical treatment of neuromuscular scoliosis]

The results of the operative treatment of 44 patients suffering from a neuromuscular scoliosis are presented. Only multisegmental procedures - also in combination with anterior methods - should be used to avoid a postoperative care with cast or brace. By means of the operation an average correction of the curves of 50.7% was achieved. The preoperative mean angle was 75.1 degrees, postoperatively a mean angle of 37.0 degrees (mean correction of 38.1 degrees) was determined. The preoperative angle, the duration of the operations, the blood loss and the quantity of the complications are higher than in idiopathic scolioses. As a result of the known tendency of deterioration in neuromuscular scolioses, the members of the Arbeitskreis Skoliose of the German Orthopaedic Society (DGOT) recommend an early operation (in progressing curves over 20 degrees) in patients suffering from a muscular dystrophy Duchenne.

The influence of lateral release on patello-femoral joint loading in knee arthroplasty. An experimental in vitro study

Eight fresh, cadaveric knees have been fitted with four different total knee cemented prostheses. Loading forces at the bone implant fixation interface of the patella component have been measured in a knee joint testing rig by four miniaturized force transducers, before and after a lateral release of the patellar retinaculum. The lateral release resulted in a significant local force reduction in the lateral and/or proximal quadrant of the patella resection plane depending on the knee flexion angle, quadriceps tensile force direction, and the patellar prosthesis design.

The effect of cement fixation on initial micromotion of the femoral component in condylar knee replacement

Four fresh, cadaveric specimens were fitted with total knee replacements and mounted on a knee joint loading and measuring rig. Femoral component micromotion in the sagittal plane was measured with a transducer during flexion and extension of the specimen. Various condylar designs were used without and with cement. Movement followed a characteristic curve pattern and was less with cement fixation particularly for bone of low trabecular strength as determined by bone sample tests for stiffness. Cement fixation appears to be superior to cementless fixation.

[Significance of dorsal decompression and instrumentation in the treatment of spinal malignancies]

From 1986 to 1990 50 patients with increasing spinal instability due to pathologic fractures of one or more vertebrae were operated in the Orthopedic Department of Mainz University Hospital. In the course of 57 operations anterior decompression and stabilization were performed 3 times, whereas dorsal spondylodesis was done with Cotrel-Dubousset's instrumentation (CDI) 32 times, with Luque's 7 times and with Harrington's 1 time; a combination of CDI and Luque was chosen in 2 cases, a combination of Harrington and Luque in 1 case. 3 times a single-stage combination and 4 times a two-stage combination of ventral and dorsal stabilization was used. The application of the CDI required no postoperative external support. 35 patients suffered from major neurologic deficits preoperatively--among them 11 from a complete and 6 from an incomplete paraparesis--which made spinal cord decompression necessary in advance of the dorsal stabilization. Of these, 16 improved significantly; however, deterioration of the neurologic status occurred in 4 cases with a paraparesis in 3 of them. Survival time postoperatively was approximately 13 months in 27 patients. 9 of these died within half a year after the operative intervention. Failure of fixation as a result of tumor lesion was found in 2 cases of CDI procedure and in 1 case of the Harrington instrumentation. All required a revisional operation. 3 patients developed a radiologic lysis of methylmethacrylate implants fixed by an anterior procedure. Posterior decompression and stabilization render possible resolution of spine pain as well as restoration of mobility until a few days before exitus letalis without restricting adjuvant radio- or chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Results of the surgical treatment of spondylolisthesis and of lumbar and sacral vertebrae which underwent spondylodesis]

Presented are the results after the surgical treatment (CDI) of 25 patients suffering from spondylolisthesis and of 25 patients with a lumbar or a sacral spondylodesis. The mean follow up reaches from 8.4 (spondylolisthesis) to 16.6 months (lumbar and sacral spondylodesis). 15 (60%) of the patients with spondylolisthesis showed an excellent or good result, in 3 (12%) the result was unsatisfactory. Only 7 of the patients of the second group were without further complaints, in 6 an amelioration of pain relief could be reached. The complications demonstrate the fault of the instrumentation in the beginning. After the development of a new screw the monosegmental fusion with CDI can be achieved in spondylolisthesis with a slipping to 70%, in more severe spondylolisthesis bisegmental fusion is necessary. The results in lumbar and sacral spondylodesis demonstrate that the operation should be only performed when all other methods have been unsuccessful.

[The importance and form of the collar in hip joint endoprosthesis. Theoretical analysis and biomechanical study]

Flat contact of the collar of the stem with the resection area of the femur in total hip replacement can often not be achieved even when the operation technique is very precise. Uneven bone patches or deviations in the resection angle lead to points of contact. If this contact area is localized to the lateral part of the collar, considerable varus torque acts on the prosthesis stem. By a simple modification, removal of the lateral area of the collar, medical bone - collar contact is achieved. It is independent from deviations in the operative procedure. In biomechanical experiments, drastic reduction in harmful torque was demonstrated by this modification. Thus, more "physiological" force transmission from the prosthesis to the bone can be expected.

[Postoperative analgesia following spondylodesis using a peridural catheter placed during surgery. Results of a pilot study]

For the treatment of postoperative (p.o.) pain following vertebral surgery, systemic analgesics are frequently used in high doses with a variety of side effects. It was the aim of this study to investigate p.o. epidural catheter analgesia in 20 patients following surgical correction of scoliosis using the Cotrel and Dubousset technique. METHODS. The patients received balanced general anesthesia with fentanyl and isoflurane. At the end of the operation, before closing the fascia, an epidural catheter was placed by the orthopedic surgeon. After extubation and following evaluation of the motor function of all extremities. 6-10 ml bupivacaine 0.25% was injected into the epidural catheter followed by continuous administration of 0.25% bupivacaine 4-8 ml/h. Analgesic level and hemodynamic parameters were monitored. Pain was measured by the visual analogue scale. If analgesia was not sufficient, the patients received tramadol or piritramide intravenously. RESULTS. In 11 of 20 patients epidural analgesia was rated adequate; 5 needed additional systemic analgesics, and in 4 effective analgesia was not achieved with either epidural analgesia or systemic opioids. No complications were observed. DISCUSSION. The pilot study documented that epidural analgesia using an intraoperatively placed epidural catheter can be used for p.o. pain relief after vertebral surgery using the Cotrel and Dubousset technique. Additional studies will compare the method described to other pain-relieving procedures.

[Recommendations for participation in sports by patients with idiopathic scoliosis]

Presented is the recommendation of the "Arbeitskreis Skoliose" of the DGOT concerning the sporting activities for juvenile patients suffering from an idiopathic scoliosis. The main points of this concept are the desirable active participation in school sport activities and the ascertainment that restrictions are not necessary in scolioses up to 21 degrees. A special recommendation for operated patients predicates the begin of sport activities after ohne year postoperatively. The kind of sport must be recommended by the surgeon, high-performance sports cannot be tolerated in those patients. Precondition for these recommendations are regularly physical examinations by the orthopedic physician and standardized x-rays in standing position.

[The problem of comparability of results of the treatment of congenital hip dislocation--exemplified by the Severin scheme and the classification system of the Work Group Hip Dysplasia]

The comparison of the results obtained by conservative or operative treatment of hip dysplasia shows that the consideration of absolute roentgenologic hip parameters is of little use. Classification principles for numerous hip parameters have been developed for this reason by Tönnis. In the Angloamerican and Scandinavian countries, on the other hand, it is predominantly the Severin classification that is employed for an evaluation of the methods of treatment. We examined in our study the differences in the evaluation of the results obtained in 117 hip joints treated by pelvic osteotomy according to Salter by application of the AKH and the Severin classification scheme. There were evident differences in all groups of these classifications. In the application of the Severin scheme the groups I, II and III contained 9.5% less, 24.8% more, and 18.8% less hip joints, respectively than in the respective groups of the Tönnis classification. In the groups IV, V and VI of the Severin classification there were altogether 3.5% less hip joints than in the respective groups of the Tönnis classification. Our study thus showed that a comparison of the operative results of hip dysplasia as presented in the Angloamerican and Scandinavian literature and those presented in the German literature is not possible. We conclude from this result that an evaluation according to a unified classification scheme would be most desirable.

[Indications for and results of the CD procedure (Cotrel Dubousset) in surgical scoliosis therapy]

At the orthopaedic University Hospitals of Mainz and Münster more than 200 patients were treated surgically according Cotrel and Dubousset procedure. By means of this operation average corrections of the curves of 50.7% to 56.7% could be reached in the first 150 patients, depending of the localisation of the curve. Operative procedure, duration of operation and blood loss are adequate to known procedures. Pre- and postoperative CT's in 24 patients with idiopathic scolioses showed a mean correction of the rotation angle in the apex vertebra of 28.5% in relation to the anterior midline of the body and of 23.8% in relation to the sagittal plane. The best corrections could be observed in lumbar curves and in the lumbar curves of double major scoliosis. A postoperative therapy with cast or braces is not necessary.

[Comparative studies on the radioactivity of bone cements containing x-ray contrast media and of the contrast media]

Various PMMA bone cements containing zirconium oxide (ZrO2) as an X-ray contrast medium and zirconium oxides of several manufacturers were tested for their radioactivity by means of a gamma spectrometer. All the bone cements tested (Implast, Palacos R, and Sulfix-6) showed a certain degree of radioactivity. The radiation source in the bone cement is the added zirconium oxide, which is polluted by radioactive elements. The examination of various zirconium oxides showed some high radioactive emissions. The risk of radiation-induced cancer seems to be small, because the cements are normally implanted in humans older than 60 years. In view of the fact that these X-ray contrast media remain in the body for decades as components of the bone cement, the radioactive zirconium oxides should be replaced by high-purity radiation-free zirconium oxide or barium sulphate as soon as possible.

Operative therapy in metastases and primary tumors of the spine

Benign and primary malignant tumors of the spine require a ventral procedure to remove the tumor and to stabilize the spine. Experience in the last years has shown that sole laminectomy in children can no longer be recommended. An instrumentation of the spine to prevent kyphosis must be performed. The rate of pseudarthrosis was of course, high when the kyphosis was treated by an exclusive dorsal instrumentation. In patients with severe kyphosis a combined procedure with ventral and dorsal operation is necessary. Solitary metastases of cancer of the prostate, breast, and the thyroid gland show a better prognosis than metastases of cancer of the lung or the stomach. Thus metastases of the first group which also show a dependency on hormones, should be operated on by a ventral procedure, independent of the location of the tumor. In cases of multiple metastases and bad condition of the patient a ventral operation is not indicated. In these cases, a dorsal procedure with decompression and stabilization allows mobility of the patients until only few days before death. An implantation of instrumentations that include a transpedicular screwing can result in spreading of the tumor to the neighboring vertebrae. Therefore, this kind of operation should be the "ultima ratio".

[Femur head necrosis. Diagnosis and morphologic analysis using roentgen, scintigraphy, computerized tomography and magnetic resonance tomography]

35 patients with a total number of 53 AVN were examined with conventional radiographs (n = 53), radionuclide scans (n = 37), CT (n = 19) and MRI (n = 53). Findings were classified according to FICAT (stage 0-IV). With a sensitivity of 96.2% and a specificity of 98.1% MRI proved to be the most accurate imaging modality especially in early stages. CT proved to be a reliable technique, too, although accuracy was less compared with MRI. Radionuclide scanning was of minor value with a sensitivity of 62.1% and a specificity of 59.5%. Typical findings with plain radiographs, radionuclide scans, CT and MRI in different stages of AVN are described.

[A computed tomographic analysis of vertebral rotation before and after surgical correction of idiopathic scoliosis]

Preoperative and postoperative computer tomographs in 24 patients suffering from idiopathic scolioses who were treated by CD (Cotrel-Dubousset) surgery, showed a mean correction of the rotatory angle in the apex vertebra amounting to 28.5% in relation to the anterior midline of the body, and 23.8% in relation to the sagittal plane. Best results were seen in lumbar curves and in the lumbar curves of double major curves. In thoracic curves only minor corrections were observed. CD instrumentation is the first dorsal procedure that allows a three-dimensional correction of the scoliotic spine.

[Comparative animal experiments on tissue compatibility and measurement of radioactivity of various roentgen contrast media]

In a comparative study the tissue reaction of several X-ray contrast materials was examined by subcutaneous and intraperitoneal application on rats. There were tested Bariumsulphate (BaSO4) and three Zircondioxyde (ZrO2) samples of several manufactures (cubic and monocline ZrO2-Feldmühle; Optipur-Merck). In the histologic evaluation no inflammatory signs could be seen. In case of BaSO4 the tissue reaction was more distinct than in the ZrO2 samples. Within the tested ZrO2 samples the differences were small; the cubic ZrO2 showed the slightest, the monocline one the relatively strongest cellular reaction. We also measured the radioactive emission by the contrast media. Here the monocline and--first of all--the cubic ZrO2 showed an alarming radioactive emission (radium 3000-11,500 Bq/kg). Only the Optipur (Merck) was free of radiation and can so be recommended for human implantation. Also the BaSO4 had no measurable radioactive Emission. Therefore only these two X-ray contrast media can be recommended for human implantation.

[The progression of untreated idiopathic scoliosis in the x-ray image]

The natural history of scoliosis, or lateral curvature of the spine, was followed up in 135 patients (111 girls, 24 boys) for a total average period of 52.4 months. We observed patients with a curvature of between 5 degrees and 30 degrees none of whom had been treated specifically as orthotics or with electrical stimulation or by surgery. Two groups of patients with progressive curvature were differentiated: 1) in 62.2% of the patients the curvature progressed by more than 5 degrees during the entire observation period; 2) in 36% of the patients we found an increase in curvature by more than 5 degrees within one year. Another result of our study was that idiopathic scoliosis is particularly dangerous in young patients with a "0" Risser sign. Thoracic curvatures and double major curvatures were more liable to progress than lumbar and thoracolumbar curvatures. Even a small angle of curvature in young patients must be taken seriously.

[Progression of Paget's disease of the spine 10 years following posterolateral spondylodesis]

M. Paget is regarded as a disease confined to the bone. Its chief characteristics are increased bone metabolism with accelerated bone reduction and precipitate bone reconstruction. One of the most common sites of the disease is the lumbar spine. Encroachment of Paget's disease from the third lumbar body to the neighbouring spinal structures is described 10 years after a lumbar spondylodesis.

[New classification of recommendations for forensic assessment of patients with scoliosis]

In 1977, for the first time, a recommendation for the expert evaluation of scoliosis-sufferers was given out. On the basis of this a new classification followed, which takes into consideration modern orthetics and new operative procedures. Unchanged are the classifications of incapacity to work with regard to decreasing lung capacity. The levels of vital capacity are still the main factor for determining lung capacity.

[Initial results of the surgical treatment of scoliosis with the Cotrel and Dubousset CD instruments]

At the Orthopaedic University Hospital Muenster 50 patients were surgically treated according to the Cotrel and Dubousset technique from June 1985 to October 1986. An outstanding characteristic of this method is the three-dimensional correction of the curve without exclusive application of distraction or transverse forces, bringing about excellent stability. By means of this operation an average preoperative angle of 63.4 degrees could be diminished to 33.9 degrees, meaning a gain of correction of 46.5%. Complications occurred essentially due to insufficient experience with this technique in the first patients operated on. After sufficient training this procedure is as practicable as the Harrington technique.

[Laceration of the vessels of the kidney hilus. A complication not previously described in halo extension treatment]

During the last years the halo traction proved to be an appropriate preoperative procedure to provide the spinal region with corrective forces, although several complications became known. As a complication unknown as yet a laceration of the renal hilus vessels is described, and the possible causes are discussed. Consequently, in case of abdominal symptoms and signs, a possible intraabdominal or retroperitoneal vascular lesion must be taken into consideration besides the well-known spinal-traction/spinal-cord-traction-syndrome.

[Long-term results of the conservative treatment of scoliosis using the Chêneau brace]

At present, we survey 52 patients who had been fitted with Chêneau braces in the years 1978 to 1980. The average primary correction of the single curved thoracic, single curved lumbar, and double curved scolioses amounted to 41%. The best late results are to be expected in the single curved thoracic and single curved lumbar scolioses that presented corrections of 14.2% and 9.2%. In the double curved scoliosis we found a correction of 5.5% of the thoracic and 5.6% of the lumbar curves. The Chêneau orthosis was well accepted by the patients. A final valuation, however, will not be possible till some years have passed.