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Biomedical subjects

J Kreutzer

Publications and source records attributed to J Kreutzer.

At least 37 records · Page 2Linked to original sources
PubMed1996

Tetralogy of Fallot with diminutive pulmonary arteries: preoperative pulmonary valve dilation and transcatheter rehabilitation of pulmonary arteries.

OBJECTIVES: This study sought to determine the results of a novel transcatheter management approach in tetralogy of Fallot with diminutive pulmonary arteries. BACKGROUND: Tetralogy of Fallot with diminutive pulmonary arteries and severe pulmonary stenosis is rare and resembles tetralogy of Fallot with pulmonary atresia: There is a high incidence of aortopulmonary collateral channels, arborization abnormalities, stenoses and need for multiple operations. Because a combined catheter-surgery approach facilitates repair in these patients, such an approach may benefit those with diminutive pulmonary arteries and pulmonary stenosis. METHODS: Clinical, catheterization and surgical data were studied retrospectively for 10 such patients undergoing preoperative pulmonary valve balloon dilation, among other transcatheter interventions, from January 1989 to January 1995. RESULTS: Initially, the Nakata index ranged from 20 to 98 mm2/m2 (mean 67 +/- 28 mm2/m2). The pulmonary valve was first balloon dilated (mean balloon/annulus 1.5 +/- 0.3), and the mean initial valve annulus Z score (-4.0 +/- 1) increased to -33 +/- 1.1 (p < 0.01) Other interventions included branch pulmonary artery balloon dilation (7 patients, 23 vessels) and coil embolization of aortopulmonary collateral channels (8 patients, 31 collateral channels). At preoperative follow-up catheterization, the mean pulmonary annulus Z score was -3.1 +/- 0.7, and the Nakata index increased to 143 +/- 84 mm2/m2 (p < 0.03). All patients underwent complete surgical repair successfully. At a mean follow-up period of 2.6 +/- 2 years, right ventricular pressure was < 70% systemic in all patients and < 50% systemic in seven. CONCLUSIONS: In patients with tetralogy of Fallot, severe pulmonary stenosis and diminutive pulmonary arteries, initial pulmonary valve balloon dilation increases the annulus Z score and anterograde pulmonary blood flow and facilities simultaneous coiling of aortopulmonary collateral channels and access for branch pulmonary artery dilation, all of which results in pulmonary artery growth, simplifying surgical management.

Abnormalities, Multiple↗
PubMed1996

Conversion of modified Fontan procedure to lateral atrial tunnel cavopulmonary anastomosis.

After modified Fontan procedures with atriopulmonary anastomoses or right atrium-right ventricle conduits, some patients have progressive exercise intolerance, effusions, arrhythmias, or protein-losing enteropathy. Theoretic advantages of a lateral atrial tunnel cavopulmonary anastomosis and published clinical results suggest that conversion of other Fontan procedures to the lateral atrial tunnel may afford clinical improvement for some patients. Eight patients (8 to 25 years old) with tricuspid atresia (n =4), double-inlet left ventricle (n = 3), and double-outlet right ventricle (n=1) underwent conversion to a lateral tunnel procedure between December 1990 and November 1994. An arbitrary clinical score was assigned before the lateral tunnel procedure and at follow-up. Before conversion, patients had decreased exercise tolerance (n = 8), arrhythmias (n = 6), effusions (n = 4), and protein-losing enteropathy (n = 8). At catheterization, all had a low cardiac index (1.9 +/- 0.7 L x min(-1) x M(-2), five had elevated pulmonary vascular resistance (>3 Wood units), and three had right pulmonary venous return obstruction by compression of an enlarged right atrium. Fenestrated lateral tunnel construction was undertaken 7.3 +/- 3.6 years after atriopulmonary anastomosis, with one early death related to low cardiac output. After the lateral tunnel procedure, two patients had no clinical improvement (no change in clinical score) but five patients had either marked or partial improvement. The right pulmonary vein compression present in three patients was resolved after conversion. The mean clinical scores improved from 4.5 +/- 1 to 3.0 +/- 2 (p < 0.04). In conclusion, conversion to a lateral tunnel procedure led to clinical improvement in five of eight patients at short-term follow-up and may be particularly indicated for patients with giant right atria or pulmonary vein compression who have symptoms. Pulmonary vein compression should be looked for in patients after modified Fontan procedures and can be relieved by conversion to the lateral tunnel procedure.

Adolescent↗
PubMed1993

Return to work for persons following severe traumatic brain injury. Supported employment outcomes after five years.

Supported employment is a recently developed rehabilitation alternative that is being used to assist individuals with traumatic brain injury to return to work. The present study reports the results of a supported employment program that has placed 80 individuals into competitive employment during a 5-year time period. All individuals had sustained a severe traumatic brain injury; 72% of the injuries involved a motor vehicle. A mean of 6.1 years had passed since injury for all participants, who had been unconscious an average of 48 days. Neuropsychologic evaluation revealed defective cognitive functioning, which contributed to diminished employment potential. A key outcome indicator used to assess return to work capacity is the monthly employment ratio, which is computed by dividing the number of months employed during an employment phase (i.e., pre/post injury) by the total possible months an individual would have the opportunity to be employed. The monthly employment ratio increased from 13% after injury with no supported employment to 67% with supported employment services. The majority of individuals were employed in warehouse, clerical and service-related occupations. A mean of 250 staff intervention hours were required to train and provide follow-up services to program participants.

Adolescent↗
PubMed1991

Costs of operating a supported work program for traumatically brain-injured individuals.

This paper presents a preliminary analysis of costs associated with a return-to-work program emphasizing a supported employment approach for persons who had sustained severe traumatic brain injuries. This analysis spans almost three years. Results indicated that a mean of 237.8 hours of staff intervention time was required to achieve job stabilization, at a cost of +6896. Ongoing follow-along and support services averaged 1.64 hours per week at a cost of +47.56. Over 68% of total staff time and costs were expended in job-site training and advocacy efforts. Application of these findings to state-level and agency-level policies should be weighed against individual characteristics and needs of clients, program design, and outcomes which clients achieve as a result of services.

Adolescent↗
PubMed1990

Neurobehavioral outcome 1 year after severe head injury. Experience of the Traumatic Coma Data Bank.

The outcome 1 year after they had sustained a severe head injury was investigated in patients who were admitted to the neurosurgery service at one of four centers participating in the Traumatic Coma Data Bank (TCDB). Of 300 eligible survivors, the quality of recovery 1 year after injury was assessed by at least the Glasgow Outcome Scale (GOS) in 263 patients (87%), whereas complete neuropsychological assessment was performed in 127 (42%) of the eligible survivors. The capacity of the patients to undergo neuropsychological testing 1 year after injury was a criterion of recovery as reflected by a significant relationship to neurological indices of acute injury and the GOS score at the time of hospital discharge. The neurobehavioral data at 1 year after injury were generally comparable across the four samples of patients and characterized by impairment of memory and slowed information processing. In contrast, language and visuospatial ability recovered to within the normal range. The lowest postresuscitation Glasgow Coma Scale (GCS) score and pupillary reactivity were predictive of the 1-year GOS score and neuropsychological performance. The lowest GCS score was especially predictive of neuropsychological performance 1 year postinjury in patients who had at least one nonreactive pupil following resuscitation. Notwithstanding limitations related to the scope of the TCDB and attrition in follow-up material, the results indicate a characteristic pattern of neurobehavioral recovery from severe head injury and encourage the use of neurobehavioral outcome measurements in clinical trials to evaluate interventions for head-injured patients.

Adolescent↗
PubMed1989

Effect of supported employment on the vocational outcomes of persons with traumatic brain injury.

This paper reports the job placement of 5 males with severe traumatic brain injury. An individual placement model of supported employment was used. All individuals were placed in competitive employment and received staggered intervention over time by trained employment specialists. A multiple baseline design across persons was used to evaluate results. All individuals had been unable to work consistently or at all in competitive work environments. The range of wages was $4.25 to $5.00 per hour with an average of 339 hours of employment specialist intervention time required per case. The major problems experienced by employment specialists were insubordinate and disruptive behaviors as well as other inappropriate social behaviors displayed at the job site.

Adult↗
PubMed1989

Helping traumatically brain injured patients return to work with supported employment: three case studies.

Three case studies illustrating the use of supported employment methods to help individuals with severe head injury are presented. Before supported employment intervention, these individuals were unable either to obtain or maintain employment. Neuropsychologic evaluation revealed many intellectual impairments which contributed to diminished employment potential. Through intervention, all three persons were able to obtain and maintain employment. Consecutive number of months employed ranged from 17.5 to 35, and hours worked per week ranged from 30 to 40. Current hourly earnings exceed the minimum wage, ranging from +5.00 to +5.16 per hour. These cases represent a subset within a larger supported employment program, which assists patients with severe traumatic brain injury to reenter the labor force and maintain employment.

Adult↗
PubMed1976

[Long-term infusion-cholangiocholecystography as a routine method (author's transl)].

The efficiency and informative values of long-term infusion-cholegraphy was examined in 30 patients with hepatic elimination dysfunction or previous negative intravenous cholangiocholecystography. It could be shown that a diagnostically useful demonstration of the biliary tract could be obtained in 29 out of 30 cases by increasing bilirubin up to 3 mg% and by infusing contrast medium for 3 hours. In spite of the increase in iodine content, the infusion of contrast medium was better tolerated than the intravenous application of contrast medium. Hepatic toxicity could not be established.

Adult↗
PubMedDate not supplied

[Effect of a rasp surface on cement penetration in paired cadaver femurs].

AIM: The purpose of this investigation was to study two different broach surface designs with regard to cement penetration into human cancellous bone. METHODS: In a cadaver study 15 paired human cadaver femora were prepared using broaches of identical geometry but different surface characteristics. All left femora were prepared using chipped toothed broaches, all right femora using diamond shaped broaches. Cancellous bone was irrigated with 1 liter pulsed lavage. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. Radiographs were taken and horizontal sections were obtained at predefined levels using a diamond saw. Microradiographs were taken and analyzed using image analysis to assess cement penetration into cancellous bone. RESULTS: Pressure curves recorded during cement pressurisation were comparable. The microradiographic evaluation revealed no significant morphometric differences in the different groups with regard to cement penetration into cancellous bone. These findings were similar in all sections obtained. CONCLUSIONS: A standardized model was developed allowing comparison of cement penetration into cancellous bone depending on bone preparation. In the presence of pulsed lavage there is no significant influence of broach surface characteristics on cement penetration into cancellous bone of the upper end of the femur.

Bone Cements↗
PubMedDate not supplied

[Significance of jet lavage for in vitro and in vivo cement penetration].

AIM: The purpose of this study was to determine the efficacy of pulsatile jet lavage and manual syringe lavage with regard to their cleansing capabilities as measured by cement penetration into cancellous bone both in vivo and in vitro. METHODS: Three separate experiments were performed. Study A: In a cadaver study 36 left human cadaver femora were used for implantation of cemented femoral components. Conventional broaches were used for femoral preparation. Bone lavage was carried out either using jet lavage or manual syringe lavage of equal volume. The allocation to two different lavage groups was randomised. In both groups high-pressurising cementing techniques were implemented with the use of a proximal seal and additional finger packing. Study B: To guarantee standardised cement pressurisation and equal bone quality, the influence of jet lavage (1000 ml) versus syringe lavage (1000 ml) was studied in 11 paired human cadaver femora in an additional study without prosthesis implantation. The specimens were imbedded in specially designed pots. Bone cement was applied in a retrograde manner and subjected to a standard pressure protocol with a constant force of 3000 N. Study C: To directly compare the effectiveness of both pulsatile jet and syringe lavage with regard to cement penetration in vivo, a new sheep model allowing for standardised bilateral, simultaneous cement pressurisation was used. After femoral neck osteotomies both femoral cavities of 10 sheep were prepared for retrograde cement application. After randomisation one side was lavaged with 250 ml irrigation using a bladder syringe, the contralateral femur with the identical volume but using a pulsatile lavage. A specially designed apparatus was used to allow for bilateral simultaneous cement pressurisation. ANALYSIS: In all studies horizontal sections were obtained from the femoral specimens at predefined levels using a diamond saw. Microradiographs were taken and analysed using image analysis to assess cement penetration into cancellous bone. RESULTS: Study A: Compared with syringe lavage the use of jet lavage significantly improved the penetration of cement into cancellous bone (p = 0.027). In the presence of strong, dense cancellous bone the findings were more pronounced. Study B: Our results show that in equal quality bone, the use of jet lavage yields significantly (p < 0.001) improved cement penetration compared to syringe lavage specimens. Study C: The results of the in vivo study confirmed the superiority of jet lavage bone surface preparation (p = 0.002). CONCLUSIONS: The use of jet lavage yields significantly improved interdigitation between cancellous bone and cement both in vitro and in vivo and should be regarded as mandatory in cemented total hip arthroplasty. High pressurising techniques are effective means to improve cement penetration, but should only be administered with jet lavage to reduce the risk of fat embolism.

Animals↗
PubMedDate not supplied

[Cemented total hip arthroplasty in Germany--an update].

AIM: The results of a national survey from 1998 had shown at the time that only around 10 % of orthopaedic surgeons in Germany had strictly implemented modern cementing techniques in total hip arthroplasty (THA). The same study was repeated 5 years later to evaluate the current situation and to determine whether modern cementing techniques have become more popular. METHODS: A detailed, slightly modified questionnaire regarding cement and bone preparation, cementing techniques on acetabulum and femur, and implant types was sent to 572 German orthopaedic and trauma hospitals, as well as to visiting surgeons with an interest in THA. In total, 293 questionnaires were available for evaluation and statistical analysis. RESULTS: Palacos bone cement remained the most widely used cement (> 90 %). The mixing times given varied significantly. Vacuum mixing systems had become more popular (67.9 %). In the femur 81.8 % of the surgeons attempted to preserve cancellous bone and 57.2 % used pulsatile lavage (jet-lavage). Retrograde cement application via a cement gun was done in 71.1 %. Cement restrictors were used in more than 95 %. Only two-thirds of the surgeons implemented sustained cement pressurisation and preferred a cement mantle thickness > 2mm (64 %). Only 16.9 % made multiple small acetabular keyholes and 48.6 % used jet-lavage. In 73.1 % no cement gun was used and in 68.3 % the cement was applied at high viscosity. Manual cement pressurisation was done in 58.1 %. The Muller straight stem device remained the most popular implant. For only 5 of the over 50 stem designs implanted have long-term results been published as yet. Only 10.6 % of surgeons/centres performed > 20 and almost 50 % implanted > 100 cemented THAs/year. CONCLUSION: The results of this survey demonstrated that, in comparison to 1998, the current state of cemented THA, in particular cementing technique has significantly improved. Future emphasis should be on continued surgeon education and training, as the operative, i. e., cementing techniques are of utmost importance for long-term success.

Arthroplasty, Replacement, Hip↗