[Biomechanical principles of after-care in replacement of the anterior cruciate ligament]

The patellar tendon graft replacing the anterior cruciate ligament undergoes histomorphological and biomechanical changes. From literature we can estimate a force of 200 N to be a critical limit of graft load after ACL-plasty in humans. The comparison with the graft loads under various conditions provided the following conclusions: Unlimited passive motion of the knee joint can be done without risk. Early weight bearing is possible. Active extension exercise against gravity could damage the graft in the range of 0 to 20 degrees of flexion in some patients. A rehabilitation protocol has to regard these biomechanical principles. In a prospective study 74 patients underwent rehabilitation according to the protocol described. An extension contracture of more than 10 degrees was seen in 9 patients. In all cases it was due to a notch-impingement or a cyclops. One year after operation 57 patients had a follow up. The side to side-difference in anterior drawer measured with a KT-1000-arthrometer was less than 2 mm in 45 patients. Six patients had difference between 2 and 4 mm. In six patients the difference was more than 4 mm.

[MR tomography of lung metastases with rapid gradient echo sequences. Initial results in diagnostic applications]

Rapid gradient echo sequences enable MR imaging (MRI) of pulmonary metastases with acquisition times of less than 1 s per slice. By optimization of this technique, density, T1- and T2-weighted images can be obtained (FLASH: TR 6.5 ms, TE2 = 3 ms, alpha = 10 degrees; T1w-Turbo-FLASH: TI 200 ms, TR 6.5 ms, TE2 = 3 ms, alpha = 10 degrees; T2w-Turbo-FLASH: TE1 = 50 ms, TR = 6.5 ms, TE2 = 3.5 ms; alpha = 10 degrees). In a prospective study 25 patients in whom pulmonary metastases were suspected were examined with three techniques in all three anatomical planes prior to surgery. All lung metastases revealed a high signal intensity on the FLASH as well as the T2w-Turbo-FLASH images, whereas vascular structures revealed a low signal intensity on the T2-weighted Turbo-FLASH images. Analysis regarding detection and correct number of lung metastases per patient with MRI compared with the histology revealed (n = 25): sensitivity of 82%, specificity 67%, positive predictive value of 95% and negative predictive value of 33%. While MRI does not currently have any diagnostic advantages over CT, the excellent differentiation of parenchymal lesions and vascular structures without the use of contrast medium and the variability of imaging planes are significant methodological advantages.

[Intramedullary pressure in the femur during boring and nailing with modern compression interlocking nails--risk of fat embolism?]

Fat embolism syndrome occurs in only 0.9-4% of patients with long bone fractures and especially with intramedullary nailing. Earlier publications have shown that intramedullary manipulation, e.g. reaming and nailing, can produce high pressures of up to 1 bar. The design of the new non-slotted interlocking compressions nails seems to increase the pressure in the femoral cavity. We measured the intramedullary pressure during reaming of the marrow cavity and insertion of compression nails (OSTEO), using cadaver femora and a piezo pressure transducer. We simulated a proximal fracture and performed 30 drilling and 20 nailing procedures. On average we detected a maximum pressure of 0.26 bar during drilling and 0.63 bar during nailing. During reaming the pressure increased when the reamer had passed the narrow diaphysis and reached the metaphysis. When the tried to enlarge the femoral canal by pushing and pulling the reamer repeatedly we measured high pressure peaks. During nailing we detected short impulses lasting a few milliseconds. The results show that the new compression nail do not produce higher intramedullary pressure than slotted nails. It is possible to avoid a dangerous pressure level by using a careful operative technique.

[TOF-MR angiography in radiotherapy treated cerebral arteriovenous malformations]

Intracerebral arteriovenous malformations represent congenital anomalies with an arteriovenous shunt (nidus). The therapeutic goal is to eliminate the risk of bleeding and to improve the clinical symptoms. The exact localization of the nidus and the identification of the feeding arteries are critical for therapy planning. Up to now conventional brain angiograms have been used for treatment planning and for the assessment of therapy response. We studied whether 3D time-of-flight (TOF) MR angiography can be used for therapy planning and monitoring. MRI and TOF-MRA studies of 28 patients undergoing radiotherapy were evaluated. They were compared to conventional angiography to assess the MRA study. A Correct identification of the arterial feeder and the nidus was possible in about 75% of the patients. In combination with the MRI study, an important 3D dataset for treatment planning could be obtained that includes therapeutically relevant information on the localization and spatial structure of the AVM as well as the adjacent brain tissue. As a noninvasive technique, close-meshed follow-up studies could be performed with MRA.

[A pharmacokinetic analysis of Gd-DTPA enhancement in MRT in breast carcinoma]

Dynamic Gd-DTPA enhanced MR of the breast was performed in one single slice in 27 patients with suspicious nodular lesions. The results could be histologically verified in all cases. A rapid spin-echo sequence with a time resolution of 8.75 s was used for the dynamic examination. The signal changes were analysed using a pharmacokinetic model which allowed parametrization of the contrast enhancement and transformation of the data into colour coded parameter images. The parameters allowed reliable distinction of 9 benign from 18 malignant lesions (p < 0.05 for "amplitude", p < 0.001 for "k21"). One fibroadenoma could not be distinguished from the carcinomas. Lymph node metastases and the pharmacokinetic parameter amplitude correlated significantly (p < 0.05).

Lateral tibial avulsion fractures and disruptions to the anterior cruciate ligament. A clinical study of their incidence and correlation

Avulsion fractures of the lateral tibial plateau, known as the lateral capsular sign, are increasingly associated with anterior cruciate ligament (ACL) ruptures. This phenomenon, known as the Ségond fracture, is a bony avulsion of the menisco-tibial ligament. Stress, which can lead to an avulsion of this kind, almost always occurs during knee flexion and internal tibial rotation, and in most cases only after damage to the primary ACL stabilizer. Examination of 151 ACL ruptures revealed a Ségond fracture in 9% of patients. Nearly all were caused by sports injuries and, understandably, the accident mechanism always included knee flexion and internal rotation of the tibial. In a similarly large number of other knee injuries without damage to the ACL, only one case of a Ségond fracture was found. This phenomenon, which is easy to detect by radiograph, can thus be regarded as a strong indication of the presence of a ligament injury.

[Systemic thinking in school psychology and education]

Public school counseling facilities have put up much resistance against the integration of systemic-psychological principles and methods into their professional field, despite the many critical reviews of their traditional counseling methods. Unlike the progressive changes and reforms which have taken place in various other institutions for children and teenagers, very few methodological changes have come forth within the field of school counseling. A serious consideration of the many proposed suggestions based upon systemic-psychological principles is long overdue. The author illustrates in this article two major trends of thought within the field of systemic psychology (the structuralistic and constructivistic schools). After highlighting the differences between these two schools, the author goes on to discuss the invariable consequences of the integration of the respective systemic methods into the traditional educational counseling programs. The emphasis has been placed upon the constructivistic school of thought, backed by provocative theses and exemplary case studies. Based upon his own practical experience the author has come to realise in this field, that systemic intervention is less time-costly than traditional school-psychological testing. For this reason, he is optimistic that a modification of traditional school counseling/psychology will come in due time. Such modification would also be sure to incite new creative interest and a greater desire for experimentation amongst the school counselors and school psychologists, not to mention a more adequate education for ongoing counselors and psychologists in this particular field.

3D MPRAGE evaluation of lesions in the posterior cranial fossa

Standard spin-echo images of the posterior cranial fossa are usually impaired by pulsation artifacts. We evaluated a heavily T1 weighted MPRAGE sequence (TR/TE/alpha/TI = 10/4/10-15 degrees/200-350) for detection of intracerebral lesions in the posterior fossa in 11 patients. Overall quality of the MPRAGE images was superior due to the lack of pulsation artifacts, high S/N and excellent gray-white matter contrast. Lesion detection was better in one patient, equal in six and inferior in four patients compared to SE technique. A cerebellar metastasis (8 mm) in one patient was completely blurred from pulsation artifacts on the SE images. Whereas multiple small lesions (< or = 4 mm) with discrete contrast enhancement were missed on the MPRAGE images in three patients. We conclude, that the MPRAGE sequence yields high quality images with isotropic spatial resolution in a reasonable time. But MPRAGE with these parameters can not replace standard SE images in screening the posterior fossa, because of a decreased sensitivity in the detection of small contrast-enhancing lesions.

Recurrent rectal cancer: diagnosis with dynamic MR imaging

PURPOSE

To evaluate whether dynamic magnetic resonance (MR) imaging can increase the diagnostic accuracy in suspected local recurrence of rectal carcinoma.

MATERIALS AND METHODS

Eighteen patients (seven men, 11 women, aged 26-78 years) with 19 suspect lesions were examined. T1-weighted (pre- and postcontrast) and T2-weighted spin-echo images were read by three observers. Computed tissue-specific enhancement parameters were obtained and displayed on gray-scale images (pharmacokinetic mapping).

RESULTS

Reading of the spin-echo images yielded a sensitivity of 91%-100% (confidence interval, 67%, 100%), a specificity of 29%-43% (12%, 67%), and an accuracy of 71%-75% (48%, 91%). Analysis of the MR data showed greater (P = .0038) and faster (P = .0018) enhancement of malignant lesions (n = 12) compared with benign lesions (n = 7).

CONCLUSION

Pharmacokinetic mapping of dynamic MR imaging data allows in vivo insight into tissue physiopathology, helping differentiate benign from malignant pelvic lesions in rectal cancer.

[Sleep apnea]

Regular and unobstructed breathing during the night is the prerequisite for an undisturbed and restful sleep. The most prevalent nocturnal breathing disturbance with morbid consequences is the obstructive sleep apnea syndrome. Forms severe enough to need therapy and, therefore, a thorough work-up, can be usually detected by a detailed history. Pathophysiology, clinical findings, differential diagnosis as well as work-up and therapy of the sleep apnea syndrome are discussed.

[Magnetic resonance spectroscopy of breast cancer]

Conservative therapeutic concepts with initial chemotherapy for patients with breast cancer represent a challenge to non-invasive techniques for monitoring response to therapy. Experimental magnetic resonance spectroscopy studies have been able to show exemplary applications for therapy monitoring of breast cancer patients. The characteristic phosphomonoester resonances and their changes during therapy are possible clinical parameters. The additional information which can be obtained from proton and carbon spectroscopy increases the amount of detectable metabolites. On-going studies are investigating clinical applications of multinuclear spectroscopic studies in patients with breast cancer.

['Cardiac ballet' with and without amiodarone]

Two well documented cases of torsades de pointes under amiodarone therapy are discussed. This special form of ventricular tachycardia is also known as "twisting around the points" or "cardiac ballet". Our first case involves recurrent torsades de pointes manifesting almost 2 weeks following onset of amiodarone therapy. They were successfully treated by overpacing. In the second case the isolated torsade de pointes was probably not caused by the longlasting and successful use of amiodarone but reflected severe ischemic heart disease and slight hypokalemia. This was confirmed in the one year follow-up, as torsade de pointes was no longer present despite increased dosage of amiodarone. Amiodarone-induced torsades de pointes is very rare. Most cases reported in the literature are poorly documented or were caused by other factors (electrolyte disturbances, other antiarrhythmic medication). If amiodarone has been administered as a matter of utmost necessity, other etiologies must be excluded or eliminated before amiodarone therapy is stopped when torsades de pointes occurs. Torsade de pointes due to amiodarone arises independently of the duration of therapy, the administered dosage and the extent of QT-prolongation. Holter monitoring does not allow a prediction and the benefit of electrophysiological studies is still controversial. The management of patients with amiodarone-induced torsades de pointes includes administration of magnesium and, frequently, overpacing. Due to the long half-life of amiodarone, prolonged temporary pacing may be required. General experience suggested that amiodarone can be used safely in patients who have developed torsades de pointes with other agents.

Diagnostic value of hemosiderin-containing macrophages in bronchoalveolar lavage

STUDY OBJECTIVE

Our objective was to determine if the hemosiderin content of BAL macrophages allows us to draw any differential diagnostic conclusions in a variety of lung diseases.

PATIENTS AND STUDY DESIGN

One hundred one patients who underwent BAL for different diagnostic reasons were studied prospectively.

MAIN RESULTS

The highest values for the hemosiderin score (HS) were found in patients with active alveolar hemorrhage and patients who had undergone heart transplantation for congestive heart failure. Compared to a control population, patients with Pneumocystis carinii pneumonia or invasive aspergillosis had a higher HS than patients with bacterial pneumonia or mycobacterial lung infection. High or intermediate values for HS were more often found in patients with a low than in those with a normal platelet count.

CONCLUSIONS

The differential diagnostic conclusions which can be based on an HS are limited.

Prospective evaluation of a prognostic score for Pneumocystis carinii pneumonia in HIV-infected patients

Serum lactate dehydrogenase levels, alveolar-arterial oxygen gradient, and percentage of neutrophils in bronchoalveolar lavage correlate most strongly with early mortality in Pneumocystis carinii pneumonia (PCP) in HIV-infected patients. However, the individual outcome can not be predicted by these parameters due to a considerable overlap between survivors and nonsurvivors. We prospectively investigated a PCP severity score, which has been developed earlier based on a retrospective analysis. Seven of 94 consecutively examined HIV-infected patients died within 14 days after diagnosis of PCP. A PCP severity score greater than 7 had a positive predictive value for early fatal outcome of 66.7 percent (6/9) and a negative predictive value of 98.8 percent (84/85). The overall diagnostic accuracy was 95.7 percent (90/94). The positive predictive value for early fatal outcome of a P(A-a)O2 > 35 mm Hg was 24 percent (6/25); the negative predictive value was 98.6 percent (68/69). However, the overall diagnostic accuracy was only 78.7 percent (74/94). The PCP severity score is a valuable tool for clinical decision making, for the early identification of patients with a prognostic unfavorable course, and for the comparison of patient populations in future studies of HIV-associated PCP.

[Significance of bronchial alveolar lavage in the diagnosis of eosinophilic pneumonia]

We describe 3 cases of eosinophilic pneumonia of unknown etiology with atypical clinical findings diagnosed by bronchoalveolar lavage (BAL). In 2 patients with subacute symptoms and restrictive ventilatory dysfunction there was no eosinophilia in peripheral blood, and chest X-ray showed a bilateral acinar and mixed interstitial-acinar pattern respectively. Transbronchial lung biopsies revealed only nonspecific changes. The third patient had acute respiratory failure and the eosinophils in peripheral blood were 1500/microliters. Chest X-ray demonstrated only minimal interstitial changes. In all instances the eosinophilic pneumonia was diagnosed by a marked BAL-eosinophilia of 25 to 45%. No specific etiology could be detected for the eosinophilic lung disease. The response to treatment with corticosteroids was prompt.

Serial chest thumps for the treatment of ventricular tachycardia in patients with coronary artery disease

Based on excellent results of successive single chest thumping (CT) and serial chest thumping (SCT) for the interruption of ventricular tachycardia (VT) in experimental animals with subacute myocardial infarction, the SCT method was applied for the treatment of VT in patients with coronary artery disease (CAD). SCT was successful in terminating 13 of 19 episodes of VT (68%) in 8 of 14 patients (57%). Conversion of VT was immediate in 9 episodes in 6 patients and latent in 4 episodes in 2 patients. Complications were rare but significant. In one case, SCT resulted in a ventricular asystole and in another case SCT accelerated the rate of VT from 167/min to 242/min, requiring electroconversion. Neither a short duration of VT nor a preserved left ventricular function seemed to enhance conversion by SCT. For interruption of VT in patients with CAD, SCT is not as successful as in the experimental animal model and, therefore, should not be used as a routine method. It may be applied in selected patients under hospital conditions with a standby defibrillator.

[Pneumocystis carinii pneumonia in HIV-negative immunosuppressed patients]

During a period of 10 years 129 immunosuppressed HIV-negative patients were evaluated for pulmonary complications. A definite diagnosis could be established in 72 cases (56%): Pneumocystis carinii pneumonia (PCP) (25), pulmonary involvement of underlying disease (10), drug toxicity (8), mycobacterioses (6), bacterial pneumonias (5), aspergillosis (5), others (13). The underlying conditions in patients with PCP were: lymphatic neoplasias (11), immunosuppression after solid organ (9) and after bone marrow transplantation (3), cytotoxic therapy for lupus erythematodes (1) and carcinoma (1). In 8 of 9 transplant patients anti-rejection therapy preceded the episode of PCP. Six patients (24%) died from respiratory failure 1 to 25 days after diagnosis of PCP, despite mechanical ventilation in four. Two patients recovered completely after mechanical ventilation for 14 and 30 days respectively. The frequency of PCP has markedly increased during the last few years: 1981-1987: 2 cases (6%), 1988: 4 (14%), 1989: 8 (42%) and 1990: 11 (26%). This can hardly be explained by improved diagnostic sensitivity or an increased number of immunosuppressed patients. Apart from the use of more potent immunosuppressive agents, the increased prevalence of Pneumocystis carinii may play an important role.

Risk factors for adverse drug reactions communication of the CHDM

In the CHDM (Comprehensive Hospital Drug Monitoring for Adverse Drug Reactions, Bern/St. Gallen), the data of the 34,838 computer registered patient admissions 1974-1988 were available for evaluation. We summarize the results of three different studies: 1. A multivariate analysis of the risk factors to developed an ADR during hospital stay, mainly the number of drugs, age, sex and renal function. 2. The occurrence rate of hyperkalemia under the treatment with diurectics, mainly potassium (K+)-losing with K+ substitution compared to the combination of K(+)-sparing with K(+)-losing preparations. 3. The occurrence-rate of exanthema in relation to amino-penicillin preparations an allopurinol. The results are presented in the communication. (Tab 7, Fig. 1, Ref. 15). Ref. 15.).

[Fever and non-specific general symptoms]

A 28-year-old man was admitted to the hospital because of fever, nocturnal dry cough and unspecific symptoms. Two years before admission he had worked as a sailor in South America, and one year ago he had been in Gran Canaria for a vacation. No serious illness occurred during these stays abroad. During the hospitalization the patient reported nausea and experienced upper right abdominal pain. Ultrasonography, computed tomography and serological tests revealed an amebic liver abscess. After administration of metronidazole the fever and symptoms subsided.

[Stress reactions--stress fracture of the upper femoral neck in endurance sports]

Stress reactions of the musculoskeletal system may be interpreted as possible precursors of stress fractures. Biological material, in contrast to artificial products, can react in numerous and complex ways. This can not only lead to a continual weakening of the tissue, but also to adaptation phenomena in response to overuse. The causes of such stress reactions are still unclear in many respects. For example, it is unknown to what extent a predisposition to these stress symptoms is created by mechanical stress alone or whether other factors such as physical condition, nutrition or even hormone balance come into play. Early diagnosis considerably reduces the healing process and, the later the diagnosis of the stress reaction, the more drawn out is the healing process and the extent of the athlete's absence from training. In this connection may be discussed whether the stress reaction can be the represent as the precursor of the stress fracture. In light of the need for taking special care in obtaining anamnestic data and determining the predisposition of an athlete, it appears to be justified to perform whole body bone scanning in the initial stages and particularly after an innocuous radiological finding. To what extent more current methods (e. g. MRI) can be applied without exposing the athlete to undue radiation cannot be conclusively judged at present. The treatment of a stress reaction should, at least at the beginning, be the same as for a diagnosed stress fracture.

[Comparative biomechanical studies of conventional and self-tapping cortical bone screws]

In normal cortical screws the thread must be cut by a separate thread-cutter. So a high stability of the connection is achieved. On the other hand thread cutting needs time, which may be assumed to several minutes during a plate osteosynthesis. To avoid thread-cutting, self-tapping screws were used 20 years ago. These old self-tapping screws had a reduced stability and a lower torque at the final screw driving so that they tended to destroy the thread. By a modification of the cutting edges at the tip of the screw the tapping quality is increased decisively. The microscopic examination showed a better cutting of the new screws with little difference to a thread-cutter. In biomechanical tests the final torque and the maximum tension force of the self-tapping screws were at the same level as in usual pre-cut screws. In the practical use the new self-tapping screws have a good handling and save time during operation. In osteoporosis, they should be used carefully in order to meet the opposite corticalis' hole and not to destroy the ipsilateral corticalis' thread.

[Hyperkalemia]

In two cases with drug-related hyperkalemia, potassium homeostasis, causes, symptoms and therapy are discussed. Iatrogenic and therefore avoidable hyperkalemia occurs most often when potassium, ACE-inhibitors, nonsteroidal antiinflammatory drugs or potassium-sparing diuretics are administered in patients with impaired renal function or diabetes mellitus. The emergency treatment in patients with severe hyperkalemia consists of intravenous calcium injections, infusion of glucose with insulin and, more recently, salbutamol. With acidotic patients administration of sodium-bicarbonate can be tried. Ion-exchange drugs and furosemide have a more delayed effect. With oliguria and anuria hemodialysis is often necessary.

[TIA--an emergency?]

Transient ischemic attacks (TIA) can be a sign of impending stroke and as such an indication of atherosclerotic disease or other impending vascular catastrophe. We discuss clinical presentation, pathophysiologic mechanisms, diagnostic procedures and guidelines for therapy using data from four TIA cases sharing certain symptoms but differing in etiology.

Recurrent meningitis in a patient with congenital deficiency of the C9 component of complement. First case of C9 deficiency in Europe

We describe the first cases, to our knowledge, of C9 deficiency in Europe that were detected in a Swiss family, of which two members--one with a complete deficiency and the other with approximately half-normal C9 levels--experienced bacterial meningitis. The index patient, a 56-year-old white man with a history of purulent meningitis at the age of 23 years, presented with an acute meningococcal meningitis. No impairment of cellular immunity or immunoglobulin deficiency could be found. Complement assays showed a complete deficiency of the C9 component, while the other individual component levels were normal and the hemolytic activity (measured using the CH50 assay) was only slightly reduced. A family study revealed complete C9 deficiency in the patient's healthy brother and half-normal C9 concentrations in his sister, his son (who also had experienced an episode of bacterial meningitis), and his niece, consistent with an inherited C9 deficiency. This first case of recurrent meningitis in a white patient with complete C9 deficiency suggests that this complement defect may also be a risk factor for bacterial, especially neisserial, infections.