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At least 145 records · Page 8Linked to original sources
PubMed2003

Single cannula technique and robotic telescopic assistance in infants and children who require laparoscopic Nissen fundoplication.

BACKGROUND/PURPOSE: Laparoscopic Nissen fundoplication (LNF) is being utilized more extensively in the management of symptomatic gastroesophageal reflux disease in infants and children. The traditional approach utilizes 5 3- to 5-mm cannulas for telescope and instrument access to the peritoneal cavity. The purpose of this study is to report the technique and document the results using a single 5-mm umbilical cannula for LNF, stab incisions for placement of the instruments, and robotic telescope assistance. METHODS: From November 1999 through March 2002, 154 patients underwent LNF by the senior author for pathologic gastroesophageal reflux disease. All operations were performed with a single 5-mm umbilical cannula through which a 4- or 5-mm telescope was placed for operative visualization. Four stab incisions were made through the upper/lateral abdominal wall under direct visualization avoiding the epigastric vessels. Through these stab incisions, instruments were inserted into the peritoneal cavity. The maximum insufflation pressure was 15 mm Hg in all cases. The ability to perform the procedure in the absence of additional operative cannula placement, complications during instrument insertion, the ability to maintain adequate pneumoperitoneum, the patient's age, weight, operating time, and the addition of a gastrostomy were recorded. RESULTS: All but one of the 154 LNFs were completed successfully using this technique. The mean age at operation and mean operating time was 23.9 months (range, 3 weeks to 180 months) and 91 minutes (31 to 160 minutes), respectively. Patients weight ranged from 2.4 to 57 kg (mean, 10.4 kg). Gastrostomies were placed in 52 cases. There were no complications associated with the stab incisions or insertion of the operative instruments through the abdominal wall. Pneumoperitoneum was maintained adequately in all cases. CONCLUSIONS: LNF can be performed safely and effectively with a single umbilical cannula. We recommend its use for pediatric patients who require LNF.

Adolescent↗
PubMed1998

Forward telescoping: the question matters.

Forward telescoping, the reporting or dating of events as being more recent than they actually were, is often observed in surveys and produces inaccurate data. We believe that some forward telescoping occurs when the question format allows people to respond without extensive retrieval of temporal information concerning the target events. We collected two types of data. The first, the type usually collected by survey researchers, involved visits to medical doctors. As is common in survey research, the actual dates of the events were not verifiable. The second type involved students' participation in laboratory research studies. Here, the actual dates were verifiable. We demonstrate that modifying the questions asked produced differences in the amount of forward telescoping in participants' responses.

Data Collection↗
PubMed1996

Measurement of photon beam backscatter from collimators to the beam monitor chamber using target-current-pulse-counting and telescope techniques.

Backscattered radiation (BSR) arising from field-defining collimators and entering the beam monitor chamber (BMC) may contribute to observed variations in medical linear accelerator photon beam output with collimator setting. Measuring the magnitude of such contributions for particular accelerators under specified operating conditions is therefore important when attempting to understand and model accelerator head scatter. The present work was conducted to confirm some backscatter measurements for collimating jaws reported previously and to extend these to include other accelerators and a multileaf collimator (MLC). BSR reaching the BMC from the jaws of Clinac 600C, 2100C and 2300CD accelerators and from an MLC on the 2300CD was investigated using both target-current-pulse-counting and telescope methods. Our measurements show that for the Clinac 600C BSR-dependent output variations are negligible. However, for the 2100C and 2300CD BSR-dependent relative output increased in an almost linear fashion, by up to 2.4% for 15 and 18 MV beams, and by up to 1.7% for 6 MV beams, as the field size varied from 5 x 5 cm2 to 40 x 40 cm2. The magnitude of BSR dependent upon collimator location in the head, as expected, thereby contributing to the collimator exchange effect. An earlier study at our centre using the telescope method had reported higher BSR levels. This discrepancy was resolved when corrections for telescope block and room scatter, previously assumed negligible, were made.

Humans↗
PubMed1986

Parameters of contact lens-spectacle telescopic systems and considerations in prescribing.

Contact lens-spectacle telescopic systems provide an alternative to conventional spectacle-mounted telescopes. There is a need to describe the parameters of such systems, the interrelations between them, and the use of such relations in selecting values for prescribing. Graphical representation of ocular (contact) lens power, objective (spectacle) lens power, separation (vertex distance), and magnification are presented. Skillful prescribing involves selection of the best set of parameters to achieve the desired visual goal in spite of the practical limitations imposed by facial features, lens availability, and appearance. Additional factors (not graphically represented) are induced vergence amplification, altered depth perception, and apparent motion, all unique to telescopic systems. One patient is described and selection of appropriate parameters is discussed. General application of the selection process is described.

Accommodation, Ocular↗
PubMed2002

The optical functional advantages of an intraocular low-vision telescope.

An implantable miniaturized telescope (IMT) for low vision has recently been developed. Surgically inserted into only one eye of patients with bilateral central visual loss, the IMT provides a nominal magnification of 3.0x and a field-of-view of 6.6 degrees (9.2 degrees for the 2.2x magnification version). Theoretical concerns have been raised regarding the ability of patients to function with a large interocular magnification difference, the impact of the monocular restriction of the field-of-view, and the impact of this design on depth perception. This article addresses these concerns regarding the design of the IMT in comparison with spectacle-mounted telescopes and combined intraocular lens/spectacle (or combined contact lens/spectacle) telescopic systems. The effective field-of-view (as determined by the combination of both the field-of-view and the field-of-fixation), the effects of head motion and the vestibular reflex, and the disruption of stereo depth perception with a monocular device are considered here. Physiological optics considerations of these issues show that the IMT may have important advantages over other designs of magnification devices for patients with age-related macular degeneration.

Depth Perception↗
PubMed1995

Telescoping and glue technique in vein grafts for arterial defects.

Fibrin glue was applied at the anastomotic site of the vein graft that was placed in rat femoral artery defects by the telescoping anastomotic technique at both proximal and distal anastomoses. All 35 vein grafts thus placed were patent, yielding a statistically higher patency rate than those placed in the same femoral artery by the same telescoping anastomotic technique but without fibrin glue. The telescoping anastomotic technique assisted by fibrin glue appears to give as reliable a patency rate as the conventional method even if it is used twice, both at the proximal and distal anastomoses, in autogenous vein grafting for arterial defects. Deformities of the inserted vessel should be minimized for patency by some means such as an application of fibrin glue so that the inserted vessel does not bulge under high arterial pressure.

Animals↗
PubMed2002

The telescoping suture--Part 1: Does this technique improve the mechanical behavior of a biomaterial?: Calf pericardium.

The authors study the mechanical behavior of calf pericardium employed in the construction of cardiac valve leaflets when subjected to telescoping suture, followed by tensile stress until rupture. One hundred twenty pericardial tissue samples were employed, 60 cut from root-to-apex and another 60 cut in transverse direction. Each of these two groups consisted of 12 control samples that were left unsutured and four sets of 12 samples each that were rejoined by telescoping suture using silk, Prolene, nylon or Gore-Tex., and subjected to tensile stress. At the rupture of the sutured tissues, the tensile stress of the suture materials ranged between 57.54 MPa for the series sewn lengthwise with Gore-tex and 114.08 MPa for the series sewn crosswise with silk. At these levels of stress, the deformation of the suture thread was much less marked than that of the calf pericardium, and internal stresses were produced that were difficult for the biomaterial to absorb. There was a loss of real load in all the sutured series when the observed resistance to rupture, expressed in kilograms, was compared with the estimated value. This loss of resistance did not invalidate the telescoping suture technique since the resistance to rupture was still much greater than that associated with suturing the two edges of the cut pericardium together. This report confirms the deleterious role of the shear force generated in the pericardium by the suture.

Animals↗
PubMed1996

Retention force changes in implant-supported titanium telescope crowns over long-term use in vitro.

Titanium is used to fabricate spherical and bar attachments for overdentures on osseointegrated implants. This in vitro study investigated the long-term effects of commercially pure titanium on the retention force of telescope crowns with conical interface. Combinations of various materials for the inner and outer crowns were tested. Telescope crowns of pure titanium showed retention force characteristics comparable to telescope crowns fabricated conventionally in a precious alloy.

Chromium Alloys↗
PubMed1983

The effect of instrumentation with a telescope during bronchoscopy on arterial oxygen tension and acid-base balance.

The effect of instrumentation with a telescope during bronchoscopy on the arterial oxygen tension and acid-base status was studied in 17 unselected, anaesthetized patients using a ventilating technique based on Sanders' method (1). After ventilating the patients with a bronchoscope and a telescope in the trachea, in the left main bronchus or in the right main bronchus, the PaO2 value was always statistically significantly higher than after ventilating only with a bronchoscope. During the course of the bronchoscopy as well as after 1 h in the recovery room, the arterial acid-base status was within normal limits and the mean PaO2 value during bronchoscopy ranged from 175 to 240 mmHg (23.3-31.9 kPa) and was 138 mmHg (18.4 kPa) in the recovery room when the patients breathed about 35% oxygen in air. The present results suggest that instrumentation with a telescope during bronchoscopy ameliorates rather than impairs the ventilation and oxygenation of the patients.

Acid-Base Equilibrium↗
PubMed1997

Periodontal and prosthetic therapy in severely advanced periodontitis by the use of the crown sleeve coping telescope denture. A longitudinal case report.

The crown and sleeve-coping (CSC) telescope denture is a removable prosthesis that is supported by both selectively retained teeth and the residual ridge or mucosa. Limited information regarding longitudinal studies of the CSC telescope denture has been reported as to the response of the abutments and their surrounding periodontal tissues to this type of design. The authors have documented a longitudinal ten-year follow-up of a case which was considered 'hopeless' for oral rehabilitation because of advanced periodontitis. The CSC telescope denture used in this case resulted in a significant improvement to the remaining dentition. The beneficial results of this form of treatment can be considered for a wide variety of clinical applications for the severely advanced periodontitis case.

Alveolar Bone Loss↗
PubMed1996

A new silicon detector telescope for measuring the linear energy transfer distribution over the range from 0.2 to 400 keV/micrometer in space.

A new telescope consisting of three two-dimensional position-sensitive silicon detectors which can measure the linear energy transfer (LET) distribution over the range from 0.2 to 400keV/micrometers has been developed as a real-time radiation monitor in manned spacecraft. First, the principle of LET measurement and its design method are described. Second, suitable electronic parameters for the LET measurement are experimentally determined. Finally the telescope performance is investigated by using, relativistic heavy ions. The first in-flight test of this type of telescope on the US Space Shuttle (STS-84) is scheduled for May, 1997.

Astronomy↗
PubMed1997

Telescoping bronchial anastomoses for unilateral or bilateral sequential lung transplantation: CT appearance.

PURPOSE: To determine the computed tomographic (CT) appearance of telescoping bronchial anastomoses. MATERIALS AND METHODS: CT scans obtained in 36 adult patients with 54 telescoping anastomoses (30 right bronchus, 24 left bronchus) were retrospectively reviewed. Seventeen scans were obtained with 10-mm collimation, one with 5-mm collimation, and 18 with 3-mm collimation. Multiplanar volume reconstruction images were retrospectively generated in 19 patients. CT findings were correlated with fiberoptic bronchoscopic findings and clinical records. RESULTS: Smooth, spherical air collections caused by diverticula of redundant mucosa were seen at the inferior or medial aspect of 22 anastomoses (41%). Endoluminal flaps and linear air collections caused by separation of the invaginated bronchus from the recipient bronchus were seen in 16 anastomoses (30%). Flaps and linear air collections were seen only at the anterior, superior, or inferior aspects of the anastomosis. Flaps and diverticula were more common at right anastomoses than at left anastomoses. No patient with an endoluminal flap or diverticulum at CT had dehiscence at bronchoscopy. Irregular air collections or posterior wall defects were suggestive of dehiscence at four anastomoses (7%). Dehiscence was confirmed bronchoscopically at two of these four anastomoses. CONCLUSION: Endoluminal flaps and linear or spherical air collections can be a normal feature of the telescoping anastomosis and should not necessarily be interpreted as dehiscence.

Adult↗
PubMed2000

Effect of adaptation to telescopic spectacles on the initial human horizontal vestibuloocular reflex.

Gain of the vestibuloocular reflex (VOR) not only varies with target distance and rotational axis, but can be chronically modified in response to prolonged wearing of head-mounted magnifiers. This study examined the effect of adaptation to telescopic spectacles on the variation of the VOR with changes in target distance and yaw rotational axis for head velocity transients having peak accelerations of 2,800 and 1,000 degrees /s(2). Eye and head movements were recorded with search coils in 10 subjects who underwent whole body rotations around vertical axes that were 10 cm anterior to the eyes, centered between the eyes, between the otoliths, or 20 cm posterior to the eyes. Immediately before each rotation, subjects viewed a target 15 or 500 cm distant. Lighting was extinguished immediately before and was restored after completion of each rotation. After initial rotations, subjects wore 1.9x magnification binocular telescopic spectacles during their daily activities for at least 6 h. Test spectacles were removed and measurement rotations were repeated. Of the eight subjects tolerant of adaptation to the telescopes, six demonstrated VOR gain enhancement after adaptation, while gain in two subjects was not increased. For all subjects, the earliest VOR began 7-10 ms after onset of head rotation regardless of axis eccentricity or target distance. Regardless of adaptation, VOR gain for the proximate target exceeded that for the distant target beginning at 20 ms after onset of head rotation. Adaptation increased VOR gain as measured 90-100 ms after head rotation onset by an average of 0.12 +/- 0.02 (SE) for the higher head acceleration and 0.19 +/- 0.02 for the lower head acceleration. After adaptation, four subjects exhibited significant increases in the canal VOR gain only, whereas two subjects exhibited significant increases in both angular and linear VOR gains. The latencies of linear and early angular target distance effects on VOR gain were unaffected by adaptation. The earliest significant change in angular VOR gain in response to adaptation occurred 50 and 68 ms after onset of the 2,800 and 1,000 degrees /s(2) peak head accelerations, respectively. The latency of the adaptive increase in linear VOR gain was approximately 50 ms for the peak head acceleration of 2,800 degrees /s(2), and 100 ms for the peak head acceleration of 1,000 degrees /s(2). Thus VOR gain changes and latency were consistent with modification in the angular VOR in most subjects, and additionally in the linear VOR in a minority of subjects.

Adaptation, Ocular↗
PubMedDate not supplied

Telescopic endolaryngeal surgery.

Magnification for endolaryngeal visualization, biopsy, and removal of benign lesions and carcinoma in situ is achieved using a telescope inserted in stripping type forceps. The combined telescope and forceps are passed easily through any standard laryngoscope with a holder. Excellent visualization is achieved through the telescope, which can be provided with 0 degree, 30 degree, or 70 degree optics. In most circumstances, these instruments obviate the use of the operating microscope, being simpler and just as exact. The field of vision, however, is smaller. The instruments are also ideal for cervical tracheoscopy and mediastinoscopy.

Equipment Design↗
PubMed1987

On buying a telescope for videolaryngoscopy.

The purpose of this article is to compare aspects of the performance of three widely-used rigid laryngoscopy telescopes. The Nagashima SFT-I, Wolf 4450.57, and Karl Storz 8702 D were used with a JVC GX-N8U camera and Panasonic PV 8600 VCR to make recordings of a one-tenth-inch grid at various distances between the lens and the grid and at two telescope holding angles. Measurements were made of the anteroposterior and mediolateral viewing fields at all distances and holding angles on maximum and minimum zoom. The telescopes were compared for viewing field, lens angle effects, holding angle effects, plane distortion effects, effects due to lens distance, color, edge definition, focus control, light source compatibility, stroboscopic use, cross-sectional diameter, fogging, and cost. An overview enables laryngologists to assess their needs before buying.

Humans↗
PubMed2002

Photon folding for imaging in nonfocusing telescopes.

We present a new technique--photon folding--for imaging in nonfocusing telescopes. Inspired by the epoch-folding method in timing analysis, the photon-folding technique directly provides the statistical significance of signals in images, by use of projection matrices. The technique is robust against common imaging problems such as aspect errors and a nonuniform background. The technique provides a deterministic recursive algorithm for improving images, which can be implemented on line. The higher-order photon-folding technique allows a systematic correction for coding noises, which is suitable for studying weak sources in the presence of highly variable strong sources. The technique can be applied to various types of nonfocusing telescopes such as coded-aperture optics, rotational collimators, or Fourier grid telescopes.

Journal Article↗
PubMed2002

Influence of the antenna diagram on a stellar interferometer that is suffering from telescope-pointing errors.

We report our experimental investigations of the influence of differential telescope-pointing errors on data corruption in an optical stellar interferometer. This effect was investigated theoretically as a function of the telescope antenna diagram, which depends on the aperture diameter. Using a laboratory breadboard consisting of a three-telescope array, we carried out the experiments with various aperture diameters and complex objects. The results matched the simulation and demonstrate that, when there is no error in pointing, a large aperture size induces correctible error but that, with a pointing error, data corruption becomes critical. In both cases, the larger the apertures, the more corrupt the data.

Journal Article↗
PubMed2004

Measurement accuracy in control of segmented-mirror telescopes.

Design concepts for future large optical telescopes have highly segmented primary mirrors, with the out-of-plane degrees of freedom actively controlled. We estimate the contribution to errors in controlling the primary mirror that results from sensor noise and, in particular, compare mechanical measurements of relative segment motion with optical wave-front information. Data from the Keck telescopes are used to obtain realistic estimates of the achievable noise due to mechanical sensors. On the basis of these estimates, mechanical sensors will be more accurate than wave-front information for any of the telescope design concepts currently under consideration, and therefore supplemental wave-front sensors are not required for real-time figure control. Furthermore, control system errors due to sensor noise will not significantly degrade either seeing-limited or diffraction-limited observations.

Journal Article↗