Biomedical subjects

P Schaller

Publications and source records attributed to P Schaller.

At least 19 recordsLinked to original sources

PubMed2006

Results of primary extensor tendon repair in relation to the zone of injury and pre-operative outcome estimation.

INTRODUCTION: The outcome of primary extensor repair in hand surgery has been widely explored, but little systematic effort has been made to investigate the influence of the anatomical zone of tendon injury. Therefore, the aim of our study was to assess the outcome of primary extensor tendon repair with a special focus on the pre-operative state and Verdan's anatomical zones. Our hypothesis being tested was that the outcome after primary extensor repair depends on the complexity of trauma and the site of lesion. MATERIALS AND METHODS: One hundred and seventy seven patients with 203 extensor tendon repairs were studied. After tendon repair and a 6-week protective immobilization, physiotherapy was carried out. A score proposed by Geldmacher and Schwarzbach was applied to estimate the outcome pre-operatively and to assess the results in a follow-up after a mean of 13 months. Correlations were tested between the anatomical zone of tendon injury, the pre-operative expectation and the results as considered both by the patient and the physician. RESULTS: In Verdan's zones 1, 2, 4 and 5, excellent or good results were obtained in the vast majority of patients. Due to a higher frequency of complex injuries with concomitant soft tissue and bony injuries, the outcome was significantly worse after tendon repair in zones 3 and 6, as expected after the pre-operative estimation. In addition, a strong correlation was found for all anatomical zones between the pre-operative estimation and the outcome as judged both by the physician and the patient. CONCLUSION: Recovery of finger function after primary extensor tendon repair depends on the complexity of trauma and the anatomical zone of tendon injury. Static splinting is an appropriate tool after primary extensor tendon repair in Verdan's zone 1, 2, 4 and 5, whereas injuries in zones 3 and 6 may demand for a different treatment regimen.

Adult↗

PubMed2005

Genetic heterogeneity of pestiviruses of ruminants in Switzerland.

We have genetically analyzed ruminant pestiviruses. All >150 bovine viral diarrhea (BVD) viruses isolated from cattle in Switzerland belonged to genotype 1, with subgenogroups e, h, k and b found in decreasing frequency. To date, representatives of subgenogroup k have been detected in Switzerland only. Despite serological evidence of Border disease in sheep, only few Border disease viruses have been isolated, all of which belong to the novel group 3. Serological evidence suggested that pestivirus infections may occur also in wild ruminants in Switzerland but no isolates are available for analysis. In addition, we describe two pestiviruses, one a cell culture contaminant and the other isolated from a buffalo, that cluster with a recently proposed novel pestivirus species.

Animals↗

PubMed2003

[Secondary reconstruction of extensor pollicis longus tendon].

BACKGROUND: Secondary reconstruction of the extensor pollicis longus tendon (EPL) can be performed using an intercalated tendon graft (ITG) or a tendon transposition, preferably the extensor indicis transposition (EIT), since a secondary suture of the EPL tendon is not possible in most cases due to degenerative changes or defect injuries. A direct comparison of ITG and EIT in one single patient collective based on a standardized follow-up protocol has not been performed yet. PATIENTS AND METHOD: For the first time, these two operative procedures were directly compared in a retrospective analysis according to the follow-up protocol after Geldmacher et al. an average of 4.3 (2 to 11) years after reconstructive surgery. Out of 1469 extensor tendon lesions only 55 patients were identified in the course of secondary reconstruction of the EPL tendon in whom additional injuries, especially osseous lesions or other conditions that affected the mobility of the thumb, could be ruled out reliably. 45 (82 %) of these patients participated in a clinical follow-up examination. In 28 (62 %) patients an EIT and in 17 (38 %) an ITG was performed. RESULTS: Neither the range of motion in the metacarpophalangeal and interphalangeal joint of the thumb, the abduction and the adduction of the thumb as well as the extension deficit and the remaining pulp-to-pulp distance during thumb opposition, compared to the contralateral hand, nor the overall evaluation showed a significant difference (Students-t-test; p < 0.05) between the results of both procedures. CONCLUSION: The EIT and the ITG for the secondary reconstruction of the EPL tendon should be regarded as equal alternatives.

Adolescent↗

PubMed2003

[The Mantero technique for flexor tendon repair - an alternative?].

PURPOSE: Regaining free tendon gliding after reconstruction of flexor tendons is essential to restore full function to the affected finger. Mantero et al. described a pull-out suture technique for the repair of flexor digitorum profundus (FDP) lesions in zone 1, allowing early postoperative active mobilisation and thus minimizing the risk of tendon adhesions. In a retrospective study we examined the results after Mantero tendon repair and compared these with the results after different reconstructive procedures in the literature. METHODS AND MATERIAL: Between 1995 and 2001, the FDP tendon in zone 1 and distal half of zone 2 distal to the chiasma respectively the flexor pollicis longus (FPL) tendon were reconstructed in 96 patients using the Mantero technique. 87 (90 %) patients, with a male to female ratio of 2 : 1, were re-examined an average of 43 (4 to 84) months postoperatively. We evaluated the isolated function of the finger joints, the total range of motion of the affected finger and grip strength and compared all values to the contralateral healthy side and assessed the functional results according to the Buck-Gramcko score and the patients' satisfaction according to the DASH score. Special attention was directed to the influence of the patients' age, gender, art of trauma, accompanying injuries or level of the lesion on the postoperative results. Furthermore, we evaluated whether clinical results depended on which finger was injured. RESULTS: 71 % (n = 62) of all injuries were found in the distal zone 2 or distal zone Th 2 in the thumb. While 81 % (n = 70) were caused by a clean cut, 10 % (n = 9) were due to a circular saw injury and 9 % (n = 8) due to a crush injury. The average DASH score value was 5.4 (0 to 37.5) with excellent and good results according to the Buck-Gramcko score in 90.8 % (n = 79) of all patients. Only the patients' age (> 50 years vs. < 20 years) and the digit involved (little finger vs. index, middle and ring fingers) had a significant influence on the postoperative results. Aside from superficial skin necrosis in 10 % of all cases, in which no further operative therapy was necessary, no other complications occurred. Interestingly, no ruptures of the sutured tendons were found, although active mobilisation was initiated immediately. Compared to the literature, the 90,8 % excellent and good results are equivalent to those of other studies concerning reconstruction after flexor tendon injuries using the Mantero technique and tend to be better than other reconstructive procedures. CONCLUSION: Based on our results, we consider the Mantero technique to be a good alternative to other forms of flexor tendon reconstruction in zone 1 and distal zone 2. Advantages include the possibility of immediate postoperative mobilisation and placing a secure tendon suture, even if the distal tendon stump is very short.

Adolescent↗

PubMed2002

[Diagnosis and therapy of necrotizing fasciitis].

Necrotizing fasciitis is a soft tissue infection with a lethality ranging up to 80%. Infection causes the activation of interleukin, tumor necrosis factor alpha, and gamma-interferon through a triggering mechanism. This results in a capillary thrombosis with necrosis of the fascia, cutis, and subcutis. The patient's history often reveals a triggering event in the form of a recent minimal trauma or operative procedure. In a fulminant necrotizing fasciitis, the development of sepsis with consecutive multiple-organ failure mainly determines the outcome of the disease. Diagnosis is made initially upon clinical findings with a rapid progression of the disease and confirmed later by histologic and microbiologic findings. Radical surgical debridement within the first 24 h with postoperative treatment in an intensive care unit represents the cornerstone of therapy. Between January 1992 and March 2001, we treated 15 patients with necrotizing fasciitis. Lethality was 33%. There was a significant correlation between risk factors (present in 86% of the patients) and morbidity. Diagnosis and therapy should be performed by an experienced surgeon. In this contribution, we discuss the most important criteria that lead to the diagnosis and the therapeutic consequences.

Adult↗

PubMed2002

[Twelve years experience in Switzerland: Quo vadis BSE?].

When the first BSE case in Switzerland became public in 1990, it precipitated a chain of events with many diverse consequences. During this time, we continued to gain knowledge, implement new measures, and make practical recommendations in order to attempt to control the disease. This was made possible by the establishment of a huge data base containing information on all cases of BSE that had been diagnosed in Switzerland, as well as by the use of information from experiences in other countries. Analysis of these data allowed the sequence of events to be described temporally and spatially and an epidemiological evaluation to be made. These data also allow predictions to be made regarding the future of BSE in Switzerland, although these predictions must be interpreted cautiously.

Animals↗

PubMed2002

Spongy hydroxyapatite in hand surgery--a five year follow-up.

Twenty-two patients were treated for enchondromas or cysts of the hand by curettage and complete filling of the defect with hydroxyapatite. Postoperatively no complications occurred and marginal osseous integration was radiologically complete after 6 to 8 weeks. Patients were re-examined after a minimum of 5 years after operation and the functional and aesthetic results were excellent in all patients. Radionuclide imaging showed identical bone activity to that in the contralateral healthy hand and there were no signs of inflammation.

Adult↗

PubMed2001

The effect of infection with bovine viral diarrhea virus on the fertility of Swiss dairy cattle.

Bovine viral diarrhea virus is a major cattle pathogen with a worldwide distribution. Animals may be infected with BVD virus transiently or persistently. Transient infection leads to protective immunity. Persistent infection is unique because it is associated with an immunotolerance that is specific to the infecting strain of BVD virus. Persistent infection results from viral invasion of fetuses between the second and fourth month of development. Such animals are of prime importance in the epidemiology of BVD because they shed large amounts of virus, and thus serve as a constant source of infection for non-immune animals. Infection of pregnant animals during the first two months of gestation may result in an increased rate of return to estrus. Animals infected in the period of five months to birth may abort or give birth to calves with malformations. The effects of BVD virus on fertility and gestation are well documented from experimental infection. However, much less is known of the extent of losses under field conditions. The main reason for this may be the multitude of other causes of increased return rates and gestation failures. In addition, the incidence of infection with BVD virus may vary over time and depends on management practices. In this study, we investigated the impact of BVD virus on gestation failures under field conditions in a large cattle-breeding area of Switzerland, where no specific measures to control BVD are in effect. Our approach consisted of relating seroconversions to BVD virus with the rate of return to estrus, abortion, and birth of calves with apparent malformations. These parameters of fertility were compared to those of animals immune to BVDV infection due to previous exposure to the virus and animals without seroconversion. Our data show that infection with BVD virus during the first 45 days of gestation did not influence the rate of return to estrus. By contrast, we observed a statistically significant increase in the abortion rate in mid-term gestation (Days 46 to 210) while no such effect was observed in the later stages of gestation. No clinically manifest malformations were observed in the offspring of animals that had seroconverted to BVD virus. In our study population the prevalence of BVDV antibody positive cattle varied only slightly between 78% and 80% over the period of observation. Our data showed that 7% (CI: 2.4-14%) of fetal deaths may be attributable to infection with BVD virus.

Animals↗

PubMed2001

[Tetanus--differential diagnosis of cerebrovascular stroke].

Report about a 80 year-old female patient admitted to hospital with dysarthria and dysphagia suspected to have had a stroke. The symptoms however were caused by a tetanus infection consequent upon a grossly contaminated ten-day-old wound. Since particularly geriatric patients are at risk of tetanus infections in industrialised countries, such patients ought to get regular booster-vaccinations.

Aged↗

PubMed2001

[Timing of soft tissue reconstruction in severe crush injury of the upper extremity].

Complex injuries of the distal forearm and the hand by industrial machines often require extensive reconstructive procedures. Crush injuries with soft tissue damage extending over the limits of visible injury require a special approach. Large soft tissue defects often have to be covered by extensive flap procedures. The optimum point of time for plastic reconstruction is an essential question and represents a controversial issue in the literature. To be able to compare different patient cohorts in the future, we classify crush injuries into five clinically relevant categories. In the course of this review article, three different cases of severe crush injuries of the upper extremity are representatively discussed. Two patients were reconstructed in a secondary procedure, one patient in the acute phase. Definite coverage of soft tissue defects in severe crush injuries should be performed secondarily after 5-7 days since the extent of damage in this special form of trauma can often only be judged after a few days and the reconstruction of bones, vessels and tendons is completed.

Accidents, Occupational↗

PubMed2001

[Coincidence of Lipoma and Liposarcoma of the Right Hand in an 84-Year-Old Patient: A Case Report].

Summary. We report the case of an 84-year-old patient presenting with a painless tumor between the thumb and the index finger. MRI showed a clearly defined tumor of the thenar eminence with a centrally localized more solid structure. There was a signal enhancement after intravenous administration of contrast medium. We performed a local resection of the tumor. Histologically, we found a lipoma with a centrally localized liposarcoma. We discuss the rare case of malignant transformation of a lipoma. In long-standing large lipomas we suggest regular controls by MR imaging.

Aged↗

PubMed2001

Effects of the inspiratory pressure waveform during patient-triggered ventilation on pulmonary stretch receptor and phrenic nerve activity in cats.

OBJECTIVE: To examine the effects of square wave, sinusoidal, and linear inspiratory pressure waveforms during pressure-controlled assist/control ventilation on the firing pattern of pulmonary stretch receptors and phrenic nerve activity. DESIGN: Experimental, comparative study. SETTING: Research laboratory at a university biomedical center. SUBJECTS: Nine anesthetized, endotracheally intubated young cats (2.5-3.4 kg). INTERVENTION: With interposed periods of continuous positive airway pressure (0.2 kPa), each cat was exposed to periods of assist/control ventilation with three different pressure waveforms, where the peak inspiratory pressure (0.74 +/- 0.13 kPa), end-expiratory pressure (0.2 +/- 0.02 kPa), and tidal volume (14.9 +/- 5.22 mL/kg) were kept constant. Preset controlled ventilator rate was set below the rate of spontaneous breathing, and the mechanical inflation time equaled the inspiratory time during spontaneous breathing on continuous positive airway pressure. MEASUREMENTS AND MAIN RESULTS: Respiratory rate and arterial blood gases did not change between the three pressure waveforms during assist/control ventilation. Peak pulmonary stretch receptor activity was lower and mean phrenic nerve activity higher during continuous positive airway pressure than during assist/control ventilation (p <.05). Peak inspiratory pulmonary stretch receptor activity was the same with all three pressure waveforms (82 +/- 17 impulses.sec-1) but occurred earlier with square wave than with sinusoidal or linear pressure waveforms (p <.05). The total number of impulses in the phrenic nerve activity burst was smaller with square wave than with the other two pressure waveforms (0.21 +/- 0.17 vs. 0.33 +/- 0.27 and 0.42 +/- 0.30 arbitrary units; p <.05), and the phrenic nerve activity burst duration was shorter with square wave (1.10 +/- 0.45 vs. 1.54 +/- 0.36 and 1.64 +/- 0.25 secs; p <.05). CONCLUSION: Square wave pressure waveform during pressure-controlled assist/control ventilation strongly inhibits spontaneous inspiratory activity in cats. One mechanism for this inhibition is earlier and sustained peak pulmonary stretch receptor activity during inspiration. These findings show that differences in inspiratory pressure waveforms influence the spontaneous breathing effort during assist/control ventilation in cats.

Adaptation, Physiological↗

PubMed2001

Inductance plethysmography: an alternative signal to servocontrol the airway pressure during proportional assist ventilation in small animals.

During proportional assist ventilation (PAV), the ventilator pressure is servocontrolled throughout each spontaneous inspiration such that it instantaneously increases in proportion to the airflow (resistive unloading mode), or inspired volume (elastic unloading mode), or both (combined unloading mode). The PAV pressure changes are generated in a closed-loop feedback circuitry commonly using a pneumotachographic signal. In neonates, however, a pneumotachograph increases dead space ventilation, and its signal may include a substantial endotracheal tube leak component. We hypothesized that respiratory inductive plethysmography (RIP) can replace pneumotachography to drive the ventilator during PAV without untoward effects on ventilation or respiratory gas exchange. Ten piglets and five rabbits were supported for 10-min (normal lungs) or 20-min (meconium injured lungs) periods by each of the three PAV modes. In each mode, three test periods were applied in random order with the ventilator driven by the pneumotachograph signal, or the RIP abdominal band signal, or the RIP sum signal of rib cage and abdomen. Interchanging the three input signals did not affect the regularity of spontaneous breathing, and gas exchange was achieved with similar peak and mean airway pressures (ANOVA). However, the RIP sum signal worked adequately only when the relative gains of rib cage and abdominal band signal were calibrated. We conclude that an RIP abdominal band signal can be used to generate PAV, avoiding increased dead space and endotracheal tube leak problems.

Airway Resistance↗

PubMed2001

Proportional assist ventilation decreases thoracoabdominal asynchrony and chest wall distortion in preterm infants.

Thoracoabdominal asynchrony (TAA) and chest wall distortion (CWD) are commonly seen in preterm infants secondary to a highly compliant rib cage and poor compensation of distorting forces by inspiratory rib cage muscles. Continuous positive airway pressure (CPAP) reduces TAA and CWD by stenting the chest wall. We hypothesized that application of positive airway pressure only during inspiration and in proportion to an infant's inspiratory effort should have a similar but more pronounced effect than CPAP alone. A ventilator providing airway pressure changes in proportion to flow and volume generated by an infant (proportional assist ventilation) was used to unload the respiratory pump during inspiration. Ten preterm infants were studied [birth weight, 745 (635-1175) g; gestational age, 26.5 (24-31) wk; postnatal age 3 (1-7) d; medium (range)]. TAA and CWD were determined by respiratory inductive plethysmography. TAA was expressed as the phase angle between the rib cage and abdominal motion and CWD as the total compartmental displacement ratio. In addition, we measured tidal volume with a pneumotachograph and esophageal and airway pressure deflections with pressure transducers. Measurements were obtained during alternating periods of CPAP and two different degrees of support (Gain 1 = 1.09 +/- 0.68, Gain 2 = 1.84 +/- 0.84 cm H(2)O/mL) that were provided by a proportional assist ventilator. Phase angle and the total compartmental displacement ratio decreased with increasing gain compared with CPAP alone. Peak airway pressure increased from 0.6 to 3.8 to 7.6 cm H(2)O above positive end-expiratory pressure (PEEP) with CPAP, Gain 1, and Gain 2, respectively, as tidal volume increased from 2.8 to 4.1 to 4.7 mL/kg. Esophageal pressure changes decreased only little with increasing gain. Chest wall excursion increased and abdominal movement decreased, indicating a redistribution of tidal volume between chest and abdomen. We conclude that proportional assist ventilation reduces TAA and CWD by generating a small increase in airway pressure that occurs in synchrony and in proportion to each inspiratory effort.

Abdomen↗

PubMed2001

Effect of positive end expiratory pressure on functional residual capacity and compliance in surfactant-treated preterm infants.

UNLABELLED: Positive end expiratory pressure is routinely used when ventilating preterm infants. Elevation of PEEP increases lung volume, as does surfactant treatment. The purpose of this study was to investigate the effect of various levels of PEEP within the range of 0.2 to 0.4 kPa on lung volume, compliance and gas exchange. We measured functional residual capacity, compliance of the respiratory system and arterial blood gases in 20 infants (median birth weight 1240 g, range 660-1690 g; median gestational age 28 weeks, range 24-32 weeks; postnatal age 3-4 days). The infants were studied at 72 hours after their last dose of natural surfactant. At this time the patients were routinely nursed at 0.3 kPa of PEEP, the PEEP level was lowered to 0.2 kPa or raised to 0.4 kPa in random order. The PEEP level was then changed to the third level 0.4 kPa or 0.2 kPa. Each new setting was maintained for 20 min before FRC, compliance and blood gases were measured. FRC was assessed using SF6 washout technique. Increasing PEEP from 0.2 to 0.3 to 0.4 kPa resulted in increases in FRC (p < 0.01) and oxygenation (ns) in all infants. In 16 infants compliance decreased and paCO2 increased with elevation of PEEP. Only in 4 infants compliance increased and CO2 fell. CONCLUSION: In the majority of our infants reduction of PEEP from 0.4 to 0.2 kPa resulted in increases in compliance and CO2 reduction. Our results might suggest that relatively low levels of PEEP < 0.3 kPa may be appropriate at 72 hours after surfactant replacement. Furthermore, these results underline the importance of PEEP test in clinical practice.

Functional Residual Capacity↗

PubMed2000

Prevalence of cattle infected with bovine viral diarrhoea virus in Switzerland.

A cross-sectional study was made in a major cattle-breeding area of Switzerland to investigate the prevalence and local distribution of animals antibody positive to bovine viral diarrhoea (BVD) virus and of persistently infected animals. The sample size and statistical analysis took into account the possible clustering of persistently infected animals on individual farms. Of 3440 animals tested on 121 farms, 1982 were found to have antibodies to BVD virus (95 per cent confidence interval for the population prevalence: 57.6+/-4.5 per cent) and 22 were persistently infected (estimate for the population prevalence: 0.64+/-0.34 per cent). The detection of persistent infection in animals less than seven months old was improved either by retesting one year later, by using an antigen-capture ELISA or, in selected cases, by the analysis of original serum samples by reverse-transcription PCR. The results showed that the prevalence of persistent infection may be underestimated by as much as one-third when antigen detection alone is used. None of the 121 farms investigated was free of antibody-positive animals and one in eight herds had at least one animal that was persistently infected. The prevalence of antibodies was lowest in seven- to 12-month-old animals (22.9 per cent) and highest in animals aged five years or over (84.9 per cent).

Animals↗

PubMed2000

Accuracy of deadspace free ventilatory measurements for lung function testing in ventilated newborns: a simulation study.

OBJECTIVE: A deadspace free method based on simultaneous ventilatory measurements in the inspiratory and expiratory limb of the ventilator circuit was compared to the conventional endotracheal method where the flow is measured between ETT and Y-Piece. The aim of our study was to find out how the arrangement of this setup affects the measuring accuracy of 1) the ventilatory and 2) the lung mechanical parameters by means of a computer simulation. METHOD: The system consisting of ventilator tubes and lung was described in state space and the flow signals of endotracheal method, of deadspace free method and the pressure at the Y-piece were simulated in the time domain. To investigate the influence of the position of the pneumotachographs (PNTs) in the ventilator circuit on measuring accuracy, the distance d0 of the PNT from the Y-piece was varied between 0 and 900 mm. The respiratory compliance C, resistance R and inertance I were calculated by least square method using the simulated flow and pressure signals of both methods. RESULTS: Compared to the endotracheal method, with increasing d0, the tidal volume measured with the deadspace free method rose linearly, depending on the ratio between the compliance of the ventilator tubes to the respiratory compliance. The differences of C and R for both methods were acceptable (< 10%) if the distance between each PNT and the y-piece didn't exceed 200 mm and the shorter do the higher the measuring accuracy. The inertance could not be measured by this method with satisfactory accuracy if d0 was higher than 100 mm. IN CONCLUSION: The dead space free method can be used for accurate ventilatory measurements during mechanical ventilation. However, for lung mechanic measurements in very low birth weight infants the position of the PNTs must be as short as possible.

Airway Resistance↗

PubMed2000

[EBV infection as etiology of otomastoiditis with peripheral facial paralysis in the child].

Case report on a 15-month-old girl with acute bilateral otomastoiditis with facial nerve palsy in the course of an EBV infection. Although the initial mononucleosis blood test was negative the diagnosis was established by the presence of blastic transformed lymphocytes with immunoreaction for the latent membrane protein of EBV, and the presence of EBV-mRNA in the majority of lymphocytes in the biopsy specimen. The occurrence of facial nerve palsy in the course of an EBV infection is relatively rare but well known. The present case involved a viral otomastoiditis with a typical course, which was complicated by facial nerve palsy after a few days of illness. A case of this kind has only once been described in an adult patient and has never been reported in a child.

Adult↗