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PubMed2000

Lower peak bone mass and its decline.

There is evidence that two-thirds of the risk of osteoporotic fracture can be predicted from the pre-menopausal bone mineral density. The frequency of osteoporosis in older women may be modifiable by implementing invention strategies in the pre- and peri-menopausal periods. Lower peak bone mineral density and bone loss can be identified in women with altered reproductive hormone or calciotrophic hormone concentrations, or selected lifestyle practices. Alterations in reproductive hormones may occur in adolescence (from an early age of pregnancy or the amenorrhoea of anorexia nervosa or exercise), in the pre-menopause (nulliparity, oophorectomy, early ovarian failure or marginal hormonal status) or in the peri-menopause. Alterations in calciotrophic hormone concentrations include corticosteroid therapy and breast cancer treatment. Lifestyle risk factors include the misuse of alcohol and possibly smoking, physical inactivity or an imbalance in dietary intake. Effective intervention currently consists of treating underlying conditions and monitoring high-risk groups.

Aging↗
PubMedDate not supplied

Comparison of three catheter sets for continuous spinal anesthesia in patients undergoing total hip or knee arthroplasty.

BACKGROUND AND OBJECTIVES: Continuous spinal anesthesia (CSA) with microcatheters may be complicated because of technical problems. In elderly patients, some of the problems may be solved by using thicker catheters. A recent invention, involving a catheter-over-needle system, may prevent leakage of cerebrospinal fluid (CSF) and may also improve the prediction of the intrathecal position of the catheter tip. METHODS: This study included 90 patients undergoing primary hip or knee replacement, randomly allocated into 3 groups, with 30 patients in each group: Group EC, a 24-gauge epidural catheter through a 19-gauge Tuohy needle; group MC, a 28-gauge microcatheter through a 22-gauge spinal needle; group SC, a 22-gauge spinal catheter over a 27-gauge spinal needle through an epidurally placed 18-gauge Crawford needle. All subarachnoid catheterizations were performed with the patient in the lateral position and the initial spinal block dose was 2 mL of plain 0.5% bupivacaine. Increments of 0.5 mL were administered when required. The block performance characteristics were recorded, and the level of analgesia was studied in a blinded fashion. Catheter function during the postoperative infusion was assessed. Afterwards the needles and catheters were examined by microscopy. RESULTS: The frequency of the successful catheterization was higher in the EC and MC groups (90% in each) than in the SC group (63%) (P <.05). The mean duration of the successful catheterizations, as well as the median level of analgesia, were similar in the groups. The postoperative infusion had to be stopped in 3, 1, and 1 patients in groups EC, MC, and SC, respectively, because of a technical reason. No neurologic sequelae occurred in this study. Microscopy showed 4 distorted spinal needle tips (2 each with MC and SC) and minor material damage of the SC catheters when bone had been met during block performance. CONCLUSIONS: Placement of the SC catheters was unsuccessful to a high degree, and bone contact produced distortion of the tip of some of these catheters. Otherwise, the quality associated with catheterization time, anesthetic distribution, and catheter function was similar with the 3 catheters.

Adult↗
PubMed2002

Transfusion medicine technology transfer: traps to avoid.

Technology transfer is the process of commercializing technology and taking it from the laboratory to the marketplace. At some stage in the technology transfer process, a due diligence will be undertaken. A due diligence is an enquiry into the technology and, in particular, its ownership. Research organizations including hospitals, universities, and blood banks need to own the intellectual property that they seek to commercialize. They own the intellectual property created by their staff in the course of employment. But volunteers, students, and collaborators, not being members of staff, will own the intellectual property that they create. This gives rise to due diligence and ownership defects, when intellectual property may in fact be owned by someone other than the research organization that seeks to commercialize it. Joint ownership can sometimes prevent commercialization. An assignment of intellectual property from a volunteer or student may sometimes be required. Such an assignment, if it inadequately deals with all relevant issues, may be void pursuant to laws throughout the world. A void deed of assignment may expose the research organization to legal liabilities. The categories of technology transfer traps to be explored are (1) ownership issues arising from the participation of students and volunteers in research, (2) ownership issues arising from collaborative research relationships, (3) ownership issues arising from the participation in research of visitors from another research organization, and (4) ownership issues arising from inventions made by employees. Each of these is considered in the context of the legal and regulatory framework in Australia, Canada, the United States of America, and the United Kingdom.

Australia↗
PubMed2001

A new device for microincremental automatic distraction osteogenesis.

We have invented a distraction device that can be placed intraorally and provides autodistraction. The device consists of two units: an implantable component that is applied directly on the bone, and an external component that is distant from the surgical site. The external component is mounted on a standard, battery-driven portable syringe driver or infusion pump. A fine flexible non-compressible tube connects the two. The compression of the bellows in the external component causes fluid to be forced through the connecting tube into the distraction component. The combination of the sealed system and incompressible fluid guarantees expansion of the bellows of the distraction component and gradually separates the bone segments.

Electric Power Supplies↗
PubMed2000

A method to locate electrode placement.

A new method uses redundancy in the 12-lead electrocardiogram (ECG) to determine the angles to all of the electrodes used to record the ECG. No other transducers or signals are needed. The method, a matrix manipulation of the standard 12-lead, would be applicable to all existing ECGs already stored on hospital systems. The invention of this method was originally motivated by the slight differences seen between ECGs acquired by the standard resting electrode placement versus those acquired in a monitoring or exercise placement. An ECG signal is acquired in multiple channels. A covariance matrix is formed. From the eigenvector solution of the matrix, the angles between the eigenvectors and the original signal vectors are determined. The angles calculated for any ECG test are compared to reference angles to determine whether the electrodes are placed in the standard ECG electrode placement, an alternative electrode placement, or an incorrect electrode placement.

Algorithms↗
PubMed2000

Shattered: Medawar's test tubes and their enduring legacy of chaos.

Medawar's 1952 paper 'An Unsolved Problem of Biology' underlies most subsequent theoretical work regarding the evolution of aging; it concludes that aging is accidental and could not have evolved; this prevents reconciling the growing body of evidence suggesting the existence of multiple, evolved, aging systems. The paper features a well-known thought experiment using test tubes to show why aging could not evolve. Medawar assumes that constant, random, breakage sufficiently represents lethal forces of nature; however, famine, drought, predation, disease, and accidents each uniquely affect populations. Predation is the only evolving force that continually invents new ways to kill members of the prey populations; thus all prey defenses to predation will eventually be defeated. Defenses to non-evolving or non-obligate lethal forces, however, should quickly evolve. Thus unevolving, identical test tubes cannot adequately represent biological populations. The example also ignores population booms and busts which often occur in nature. By ignoring these issues, Medawar examines only one population age distribution skewed towards younger individuals in predator-dominated environments while ignoring predator-free populations skewed towards older individuals after population crashes. Further, Medawar's test tubes lack meaningful competition for finite resources, and ignore declining fertility which occurs in all aging species. Medawar concludes that older individuals are too few in number to influence the population's gene pool for or against aging. This conclusion is found to be incorrect when variations in the age of reproductive senescence are introduced into a predator-free population.A new thought experiment with competing strains of algae corrects for these issues and shows that aging evolved and is retained so that groups retain enough genetic variability to allow for rapid evolution of a defense to novel predation. The example shows reasons why the rate of aging is directly linked to the reproductive rate, litter size, metabolic rate, reproductive senescence, and fixed body size. It also suggests that in the absence of predation, immortality would quickly evolve if not for the evolution of highly-conserved aging systems. Prior analysis of aging evolution is incorrect due to theorists' rejection of the idea of group selection. It is believed to be 'impossible' to select for mutations that are bad for the individual but good for the group. However, mutations that are neutral to young individuals which are only deleterious if expressed at older ages can accumulate in early-mortality, predator-dominated environments. Removing the predator allows deleterious mutation expression. Positive group selection then occurs amongst traits that are negative to the individual. Further, group selection is a universal force that occurs between local, non-breeding groups and not, as theorists propose, between distant groups of potentially interbreeding species. Local survivors migrate to replace extinct, related species. The antagonistic pleiotropy theory, which was created to salvage the idea of accidental aging, is examined and shown to be untenable. The hypothetical antagonistic pleiotropy genes that are beneficial to young while detrimental to old individuals, predicted to exist in the 1950s, are unlikely to exist, have not, and likely will not be found in sufficient quantity to participate in the aging process.

Aging↗
PubMed2000

[Promoting non-smoking behavior in 13-year-old students in primary schools and high schools. A prospective, randomized intervention study with 1,956 students].

1956 7th grade students of high schools and secondary modern schools in three cities with 110,000 to 180,000 inhabitants were asked about cigarette, alcohol and drug consumption using questionnaires. Subsequently 1080 of the students took part in a newly invented non-smoking curriculum which was held during 8 lessons within 4 weeks (intervention group (I)). The lessons were performed by non-smoking physicians who had passed a training programme before. 876 students served as control (C) group. 2 years later the questioning was repeated. The number of students who started smoking within the two years was significantly lower in the intervention group. In the high schools a significant effect was seen in boys (I: 13.0%, K: 22.4%; p < 0.01) and girls (I: 21.4%, K: 28.4%; p < 0.05) whereas in secondary modern schools a significant effect was seen only in boys (I: 17.4%, K: 25.2%; p < 0.05) not in girls (I: 18.0%, K: 22.0%; n.s.). First-time consumers of drugs like cannabis, marihuana and organic solvents were found less often in the intervention group among boys in high schools than in the control group (I: 14.9%; K: 23.6%; p < 0.05). No effects of the intervention were seen in girls of high schools and in students of secondary modern schools. No effects of the intervention were seen on alcohol consumption. Students who drank beer, wine or liquor several times a week were found at the same rate in the intervention and control groups. We conclude that a non-smoking intervention of 8 lessons in the 7th grade of high schools and secondary modern schools may lower the rate of first-time consumers of cigarettes but not of alcohol and drugs.

Adolescent↗
PubMed2000

Hazards of bicycling: from handlebars to lightning.

The bicycle, an invention that provides joy and transportation to millions of people, can also be a source of disabling injuries and death. The victims of bicycle accidents are usually in good health and often young. Most of the fatal head injury cases are teenagers. In this article, I have chosen four areas of bicycle trauma that frequently brings the bicycle patient to the attention of a neurologist. These areas are (1) head trauma as a consequence of road collisions; (2) compressive ulnar neuropathy; (3) impotence, probably due to compression of the pudendal nerve or its branches; and (4) lightning-related bicycle injuries. The one thing that all four categories have in common is that they are often preventable. Helmet usage and common sense would lower the number of serious head trauma cases by 50%. Compressive ulnar and pudendal neuropathies can be prevented or reduced if the cyclist would frequently change his or her position in relation to the handlebar and saddle. In the majority of cases of compressive neuropathies, the symptoms improve if the patient takes a holiday from bike riding. Lightning injuries can be avoided or lessened if the cyclist takes proactive measures to limit his or her exposure during thunderstorms. These proactive measures include knowing the climate patterns of the area and knowing where the nearest safe shelter is located.

Accident Prevention↗
PubMed2001

[Fritz König (1866-1952): pioneer of osteosynthesis and his influence on traumatology].

Fritz König (1866-1952) was 1918-1935 ordinary professor of surgery at the University of Wuerzburg. A main interest of his work was the technique and indication of osteosynthesis. Since 1900 he investigated methods (wire suture, intra- and extramedullary splint, external fixator, plate) and materials (ivory, steel; wire, screws). All his life he aimed to standardize the technique of osteosynthesis, to work out and spread clear indications for the surgical treatment of fractures, and to carry his point against the resistance of the social accident insurance caused by bad results of a lot of surgeons. His importance is not based on the invention of a great deal of instruments but on his endeavour for the fundamentals of osteosynthesis.

External Fixators↗
PubMed2001

[The ProSeal-LM, a new variant of the laryngeal mask: description and first clinical results].

The ProSeal-LMA is a modification of the laryngeal mask airway (LMA) invented by AIJ Brain. It differs from the known models in three major respects: An additional lumen extending into the tip of the cuff allows insertion of a gastric tube. A pocket immediately behind the cuff accommodates a finger or a siliconated metal introducer and thus facilitates insertion. An additional cuff at the dorsal aspect of the mask pushes the mask into a ventral direction and thus improves the seal around the glottic opening. Our experience after 8 months of clinical use and first data from an international multi-center-study (24 ProSeal-LMA/24 Standard-LMA) are reported. With a ProSeal-LMA insertion of a gastric tube is much easier and more reliable than with a Standard-LMA (24/24 patients vs. 2/24 patients). Judged from visibility of the oesophagus during fibre-endoscopy the position of the ProSeal-LMA is superior to that of the Standard-LMA. Both are equally well tolerated and handled. Most remarkable is a better seal for the ProSeal-LMA (pressure for a leak of 3 L/min: 31 mbar compared to 20 mbar (mean) for the Standard-LMA). Therefore the ProSeal-LMA seems suitable for anaesthesia procedures with IPPV, which up to now are a domain of endotracheal intubation.

Adolescent↗
PubMed2001

[Diagnosis and therapy of laryngeal diseases in the history of medicine. I: The pre-laryngoscopic era].

BACKGROUND: ANATOMY, PHYSIOLOGY AND PATHOLOGY: Hippocrates and Aristotle did not yet have a clear idea of the anatomy and physiology of the larynx. 500 years later Galenos carried out subtle studies on animals and elaborated a fairly precise description of the different cartilages, muscles and nerves of the larynx; he was the first to demonstrate the superior and the recurrent nerves of the larynx. He performed numerous experiments on animals with temporary or permanent interruption of the nervous function and thus developed a correct opinion of the vocal physiology. However, he did not draw clinical conclusions from his knowledge. In the 16th century the macroscopic anatomy of the larynx was elaborated further bei Andreas Vesalius, Fabricius ab Aquapendente et al.; Jacob Henle in 1838 described the different epithelia in the larynx, based on microscopic studies. The pathology was inaugurated by Giovanni-Battista Morgagni in 1761, including the pathology of the larynx. Francis Home in Edinburgh (1765) and Pierre-Fidèle Bretonneau in Tours (1826) made the first studies on croup and diphtheria and coined these names. Fr. Hermann Albers in Bonn in 1829 published the first monography on diseases of the larynx, incorporating more than 80 relevant case reports from the literature and numerous observations of his own. The first system of the pathology of the larynx was put up by von Rokitansky in Vienna. DIAGNOSIS AND THERAPY OF DISEASES OF THE LARYNX: Before the invention of laryngoscopy the physicians could deduce the underlying disease only from the clinical symptoms like hoarseness, dyspnoea, dysphagia. The conservative therapy followed the theory of humours and included bloodletting, leeches, purgatives and emetics; the surgical procedures were blind caustery with silver nitrate and ablation of polyps guided by palpation and scarification with a knife in cases of oedema; in desperate dyspnoea endonasal intubation was attempted (Desault 1789-1803) or a tracheotomy performed. Concluding the chapters a typical patient history of 1813 with a case of purulent laryngitis where most of these measures were applied but could not avert but rather provoked the death of the patient. This historical development is described with numerous anecdotic details.

Animals↗
PubMed2002

[Diagnosis and therapy of diseases of the larynx in the history of medicine].

BACKGROUND: FIRST CLINICAL APPROACHES. Bozzini in Frankfurt, Germany, in 1806 constructed the first endoscope, by which cavities of the human body could be inspected through a tube, but he was hardly able to demonstrate the larynx. His attempts were continued by Avery in London in 1840 with special view to the larynx but were not successful. Babington in London in 1829 constructed a glottiscope combining an angled mirror with a depressor for the tongue. He will probably have been able to inspect the larynx in some cases, but he did not continue these studies. Liston in London in 1837 reported that he had seen pathological findings of the larynx in a few cases by means of an angled mirror. FIELD OF RESEARCH: PHYSIOLOGY OF THE VOICE. Ferrein in Paris in 1741 was the first to carry out experiments on human larynges. These were continued in a systematic way by the physiologist Johannes Müller in Berlin in 1837 analysing the movements of the vocal cords. Manuel Garcia, a Spanish singing teacher, first in Paris, later in London, had studied the anatomy of the larynx very carefully, especially the muscle fibres. In 1855 he succeeded in inspecting his own larynx by means of an angled mirror and observed and described the movements of the vocal cords in great detail. At first his discovery did not arouse great attention, but later he was honoured very much as the inventor of laryngoscopy. SYNTHESIS OF PHYSIOLOGY AND CLINIC: Vienna 1857/58: The physiologist Carl Ludwig was preparing the second edition of his textbook on physiology, in which he extensively referred to Garcia's technique of laryngoscopy. His collegue Ernst Brücke was working on the physiological basis of phonetics. Johann Nepomuk Czermak, also a physiologist, was a guest of Brücke's and Ludwig's in Vienna during the winter 1857/58 and was inspired by the research work of his hosts. The neurologist Ludwig Türck had made experiments to visualize the human larynx in bodies and patients without knowing of Garcia's achievements. Since he used sun light only he had interrupted his studies in autumn 1857 and had lent his instrument, a mirror similar to that used by Garcia, to Czermak. Czermak used artificial light and the perforated concave mirror that had recently been introduced into ophthalmology. He was at once successful in inspecting his own larynx. He reported on this as early as March 1858 without informing Türck, although he mentioned him and the mirror that he had lent him. There was a public dispute about the priority between Türck and Czermak which drew wide attention to the invention of laryngoscopy which now was readily introduced in practical medicine forming the new discipline of laryngology. This development is delineated with many anecdotal details.

Europe↗
PubMed2002

[The centennial of oxygen-therapy (1902 - 2002)--reassessing its history. Part I: "The long way of oxygen"--from its discovery to its implementation as a rational therapy in anaesthesia and emergency-medicine].

This historical survey in two parts analyses the history of inhalative oxygen therapy and its interactions with the history of anaesthesiology. For this purpose, we will start with illustrating "the long way of oxygen" from its first isolation by Carl Wilhelm Scheele (1772) and Joseph Priestley (1774) to its breakthrough for therapeutic application in the 20th century. We will show that the two main factors delaying the successful implementation of a truly rational oxygen therapy were of technical nature: The complicated and costly production of the gas and insufficient means to apply it continuously and with reliable and sufficient dosages to the patients. Both problems could not be satisfactorily solved until 1902. From this year on, however, the "Linde Process" allowed cheap mass-production of oxygen. Simultaneously, various inventions of modern pressure gas technology allowed to solve the application problems. Here, a special significance is to be awarded to pressure reducing valves. These were first introduced into medical technology by Draeger Inc. (Lübeck/Germany) on a significant scale, proving particularly successful in anaesthesia and rescue-devices (e. g. in the "Roth-Draeger Anaesthesia Apparatus" [1902]). Critically discussing earlier research on the history of oxygen therapy, we therefore propose a historical reassessment, accepting the year 1902 as the internationally decisive "turning point" towards the development of modern oxygen therapy.

Anesthesiology↗
PubMedDate not supplied

[Correction of deformities with conventional and hexapod frames--comparison of methods].

AIM: Distraction osteogenesis for the correction of deformities with an external fixator is well established. The hexapod principle of robotic technique was invented for the Ilisarov apparatus (e. g. Taylor-Spatial-Frame/TSF). Treatment with conventional frames needs a patient-customised frame mounting. This demanding procedure is markedly reduced using this technology. The aim of this study was to analyse the value of the hexapod principle in external fixation. METHOD: The potential of a frame to correct deformities is limited by its work space. The geometry of a conventional frame is different from the geometry of a hexapod frame, which is the reason for their different work spaces. The work space of the hexapod frame is compared to the work space of a conventional frame. Important parameters for this analyses are minimal and maximal frame heights and the potential of correction. RESULTS: The minimal frame height of hexapod fixators is higher compared to conventional Ilisarov fixators. The standard hexapod frame (TSF 155 mm ring diameter) can correct 23 degrees of angulation, 36 mm of shortening, 71 mm of translation and 43 degrees of rotation without changing the telescope rods. The standard conventional frame (160 mm ring diameter) can correct 90 degrees of angulation, 100 mm of shortening, 25 mm of translation and 12.5 degrees of rotation without remounting of the frame. CONCLUSION: The different work spaces of the different frames result in consequences for their clinical application. The hexapod frame has more power to correct translation and rotational deformities than a conventional frame. Correction of extensive angulation and shortening deformities almost always needs an exchange of telescopic rods. Conventional frames are usually able to correct these deformities with the primary mounting. Because of its increased minimal frame height, the indication for hexapod constructs in child orthopaedics can be limited.

Adolescent↗
PubMed2003

[Simultaneous digital ICG and fluorescein videoangiography with the personal computer].

BACKGROUND: Since the invention of the simultaneous ICG and fluorescein (SIF) videoangiography in 1995 none of the available SLOs were significantly improved. Digital video recording with a PC can simplify and improve the quality of the angiography. METHOD: SIF angiography images of a two-wavelength scanning laser ophthalmoscope were digitized with a personal computer and written to disk with at rate of 25 images/s as a non-compressed digital video file. The digitized image sequence could be replayed with any standard video player and converted to different image and video file formats with a file conversion utility, developed specifically for the needs of SIF angiography. RESULTS: Recording of digital SIF videoangiograms with a personal computer is not more complicated than the conventional video method. Since most of the parameters of the recording software are customizable, processing methods can be tailored to individual needs. Off-line processing and/or storage of the images in a digital database are possible immediately after recording. To facilitate localization of the pathological landmarks on the fundus the two channels of the SIF angiograms can be observed as combined red-green images. CONCLUSIONS: Compared to conventional videoangiography, digital SIF videoangiography has only advantages: the image quality is better, it is less complicated and not more expensive than the conventional one. Digital recording should replace the conventional one.

Cost-Benefit Analysis↗
PubMed2004

[100 years of Draeger Medical Technology (1902 - 2002) -- working for the applicability of oxygen].

This survey analyses the history of 100 years of Draeger Medical Technology. Between 1889 and 1902 a number of inventions on the field of pressure gas technology allowed to solve application problems, which until then proved major obstacles to the safe and efficient use of compressed gases such as oxygen, nitrous oxide or carbon dioxide for medical and industrial purposes. A special significance is to be awarded here to pressure reducing valves, but also reliable manometers, nozzles and valves for pressure tanks were not generally available until then. These were first successfully and on a really significant scale introduced into international medical and non-medical pressure-gas technology by Draeger Inc. (Luebeck/Germany), and proved particularly successful in anaesthesia and rescue-devices (e. g. in the "Roth-Draeger Anaesthesia Apparatus" (1902). Consequently, starting in 1902, Draeger Inc. increasingly put an emphasis on developing medical and rescue technology and -- by doing so -- gained an important influence on the history of the implementation of modern oxygen therapy and of inhalative anaesthesia. A survey of the historically most important Draeger-Developments is provided.

Anesthesiology↗
PubMed2005

[LED autoregistration in navigated endonasal sinus surgery].

BACKGROUND: In endonasal sinus surgery, computer aided surgery (CAS) is a generally accepted method. Applying CAS, there are basic problems with the constancy of accuracy at a free mobile patient head as well as with extended referencing time. The navigation system manufacturer Stryker-Leibinger invented together with our working group a non-invasive, frameless, automatic patient registration and simultaneous tracking system for navigated endonasal sinus surgery. With this new user-friendly system it concerns an active, LED-based, self-adhesive on the surface of splanchnocranium autoregistration mask. MATERIAL AND METHOD: The LED autoregistration mask was tested in an anatomic cadaver study and an ongoing clinical patient study regarding manageability, applicability and accuracy. Accuracy measurements were accomplished on different control points of the head in the cadaver study. The determination of accuracy was calculated with the metric Euclidean distance. Further we report on our experiences with a total of 20 patients applying the new mask. To control the accuracy, anatomic landmarks of the patients were adducted. Goal of our study was to determine the accuracy of the LED mask and to compare it with titanium screw markers, the valid reference gold standard. RESULTS: The LED autoregistration mask convinced by a high precision with relatively simple useability. Total accuracy amounted to 2.22 +/- 0.91 mm. The LED system proved to be a valuable orientation guide mainly at revision surgeries with modified anatomy. CONCLUSIONS: LED surface autoregistration is especially suitable for endonasal sinus surgery and represents a very helpful tool for the rhinosurgeon. Our accuracy studies have shown that the LED autoregistration mask is comparable to the gold standard titanium screw markers and, in addition, very reliable.

Computer Graphics↗
PubMed2005

VDD-pacemaker in children--a long-term therapy?

AIMS: Transvenous AV-synchronous pacing in children started with the invention of smaller sized VDD leads and miniaturization of pacemakers. Whether or not this is a favourable long-term therapy was retrospectively investigated by us based on data from our records. METHODS: From May 1977 to July 2001 we implanted pacemakers in 104 children younger than 15 years of age. In 55 patients transvenous leads were implanted. Twelve of these (21.8 %) received a VDD pacemaker for hemodynamic reasons. RESULTS: Ages ranged from 11 months to 14.5 years (mean 7.7 +/- 4.3 y). Sizes of the children ranged from 67 to 141 cm (mean 105.9 +/- 15.5 cm) and body weight ranged from 5.3 to 62.0 kg (mean 22.5 +/- 9.8 kg). The mean follow-up period was 47.5 +/- 15.1 months. In 86.3 % of the time during follow-up pacemakers of which we obtained data were working in the VDD mode. Five of the twelve VDD patients (41.7 %) had to be reoperated because of severe traction on the leads. In all five patients the VDD systems were explanted and the patients changed to dual chamber pacemakers. The period of time between implantation and VDD lead explantation ranged from 24 to 74 months (48.6 +/- 18.5). CONCLUSIONS: VDD pacemakers can be implanted safely even in children with a low complication rate perioperatively. 41.7 % of our VDD patients had to be reoperated within the surveillance time because of severe lead tension due to thoracic growth. In our experience VDD pacemakers in smaller children seem to be a temporary solution to bridge AV-synchrony from a young age to DDD pacing in young adulthood.

Child↗