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At least 73 records · Page 4Linked to original sources
PubMed1983

Detection of bone marrow invasion by neuroblastoma is improved by sampling at two sites with both aspirates and trephine biopsies.

Two hundred and eight serial bone marrow samples from 49 consecutively diagnosed children with neuroblastoma were studied retrospectively for evidence of tumour invasion. Bone marrow involvement was found in 24 patients at diagnosis and in four more at a later stage in their disease. Trephine biopsies were more effective than aspirates for tumour detection in 20% of the 154 paired aspirate/trephine procedures, whilst the reverse was the case in 7%. Imprints of trephines gave no additional information. Bilateral sampling (aspirates and trephines) improved the tumour detection rate by 10% over that attained by sampling a single site. There was some correlation between specific appearances in aspirate and in trephine samples, for example the hypocellular smear and the trephine biopsy showing much stromal reaction to tumour infiltration. Bilateral iliac crest bone marrow aspirates and trephine biopsies are indicated in children with neuroblastoma, both for initial staging and for monitoring of progress.

Biopsy↗
PubMed1992

Use of paraffin wax embedded bone marrow trephine biopsy specimens as a source of archival DNA.

AIMS: To evaluate the use of DNA extracted from paraffin wax embedded trephine biopsy specimens as a source of archival nucleic acid for Southern hybridisation studies and polymerase chain reaction (PCR) amplification. METHODS: DNA was extracted simultaneously from paraffin wax embedded bone marrow trephine and lymph node biopsy specimens after incubation of tissue sections for one to five days in lysis mix and proteinase K with periodic sampling. DNA from 10 trephine biopsy specimens was subjected to PCR amplification using HLA-DPB primers to determine whether the extracted nucleic acid was of sufficient quality to permit amplification. RESULTS: For most specimens the greatest yield of high molecular weight DNA was seen after five days' incubation. Unlike lymph node material the quality of extracted nucleic acid and the quantity obtained from trephines was insufficient for Southern blot analysis. PCR amplification using HLA-DPB primers yielded positive results in six out of 10 trephine biopsy specimens. CONCLUSIONS: DNA extracted from paraffin wax embedded trephine biopsy specimens is largely degraded and unsuitable for Southern analysis but serves as a useful source of archival nucleic acid for PCR amplification.

Biopsy↗
PubMedDate not supplied

Calibration of trephine blade depth.

PURPOSE: To assess the accuracy and precision of the Barron radial vacuum trephine as an instrument for corneal lamellar dissection. METHODS: We describe a practical method to calibrate individual trephines prior to lamellar corneal procedures using the calibration microscope designed for diamond knives. RESULTS: We observed that one turn (360 degrees) of the trephine produced a mean blade displacement of 0.25 mm. However, individual trephines demonstrated a significant range of variability. CONCLUSION: For highly accurate trephination, it is useful to calibrate each individual trephine using the calibration microscope.

Calibration↗
PubMed2006

Intra-individual variability of penetrating keratoplasty outcome after excimer laser versus motorized corneal trephination.

PURPOSE: To assess the intra-individual variability of outcomes after penetrating keratoplasty by comparing mechanical and nonmechanical corneal trephination. METHODS: Fifteen patients (30 eyes, 16 with keratoconus and 14 with Fuchs' dystrophy; median age at penetrating keratoplasty 56.3/53.5 years) were assessed whose trephination was performed using a motor trephine in one eye and the 193-nm excimer laser (MEL 60, Carl Zeiss-Meditec) in the other eye by one experienced surgeon. Subjective refractometry, standard keratometry, and corneal topography were used to assess best spectacle-corrected visual acuity (BSCVA); spherical equivalent refraction; keratometric and topographic central corneal power; refractive, keratometric, and topographic astigmatism; surface regularity index; surface asymmetry index; and potential visual acuity preoperatively, before first suture removal (at 1 year), and at last available follow-up after final suture removal but before additional surgery (1.3 and 1.9 years, respectively). RESULTS: Before first suture removal BSCVA was significantly higher (0.7 vs 0.5; P=.008) after excimer laser trephination. At the end of follow-up, refractive/ keratometric/topographic astigmatism (2.20/2.10/2.40 diopters [D] vs 5.00/6.00/7.10 D) and surface regularity index (0.8 vs 1.1) were significantly lower (P=.02, P=.005, P=.01, and P=.03, respectively) and potential visual acuity was significantly higher (0.9/0.6; P=.02) after excimer laser trephination. CONCLUSIONS: During long-term follow-up, all-sutures-out postkeratoplasty astigmatism and surface regularity are superior in the eye where nonmechanical excimer laser was applied in contrast to the fellow eye with motor trephination in the same individual.

Adult↗
PubMed1978

Trephination of donor corneal buttons: a scanning electron microscopic study.

Corneal buttons were cut from cat and human donor eyes by anterior trephination (with or without scissor completion) and from excised corneoscleral rims by posterior trephination (with or without a press). Scanning electron microscopy was used to evaluate the slope and quality of the cut edge, the diameter of the section of Descemet's membrane that was actually cut, and the loss of endothelial cells around the cut edge. With anterior trephination, the diameter of the section of Descemet's membrane that is cut was found to be less than that of the trephine because the cut edge slopes inward. Posterior trephination with or without a press consistently produced circular buttons with accurately cut outward-sloping edges. This resulted in a diameter of Descemet's membrane which was greater than in the anteriorly trephinated buttons. There also was less damage to peripheral Descemet's membrane and endothelium with the posterior method, especially when compared to scissor cut buttons. A 360 degree peripheral ring of Descemet's membrnae (0.05 to 0.28 mm in width) was denuded of endothelial cells with all techniques.

Animals↗
PubMed1978

[Comparative studies with scanning electron microscope on the quality of corneal disk incision using various corneal trephine (author's transl)].

The cut surface of corneal stroma from rabbits was studied with a scanning-electron microscope and compared after using a manual trephine, a motor-driven rotor trephine and a rotor trephine with mechanical guidance. It became evident that the cut surface obtained with the motor-driven trephine is clearly smoother than that obtained with manual trephine. A further improvement in the quality of the cut is evident with a mechanically guided trephine.

Animals↗
PubMedDate not supplied

Comparison of three corneal trephines for use in therapeutic penetrating keratoplasties for large corneal perforations.

Corneas with large perforations complicate penetrating keratoplasty due to the increased risk of anterior chamber collapse they pose. We hypothesize that suction trephines should produce more uniform corneal openings than non-suction trephines. Penetrating keratoplasties using Franceschetti-type freeblades, and Hanna and Hessberg-Barron suction trephines were performed on human eye bank eyes with large corneal perforations. The trephined corneas' histologic appearance was graded according to depth, sharpness, and perpendicularity of cut. Suction trephines were easier to use, resulted in less anterior chamber collapse, caused less corneal distortion, and created a sharper, deeper and more perpendicular incision. The Hessberg-Barron and Hanna trephines performed better than the freeblades in this study.

Anterior Chamber↗
PubMed1996

Laparoscopically assisted trephine stoma formation.

A trephined stoma allows a quick postoperative recovery when a concomitant laparotomy is not necessary. However, both colostomies and ileostomies are associated with a significant short- and long-term complication rate. Review of 25 conventional trephine colostomies showed a complication rate of 20% over 5 years (three hernias and three prolapses in five patients). A laparoscopically assisted method for trephine stoma formation is described that overcomes the disadvantages of the conventional trephine technique; namely the tendency to enlarge the trephine to mobilize the mesentery, leading to prolapse; tension on an inadequately mobilized mesentery, leading to retraction; and difficulties in the orientation of an end stoma. This method was used to fashion six colostomies and one ileostomy with no complications. There was a shorter convalescence and initial stoma care was easier. This procedure is preferred for temporary or permanent stoma formation when a laparotomy is not necessary because it allows a precise trephine mobilization of the mesentery and confirmation of orientation of the bowel.

Anastomosis, Surgical↗
PubMed1994

The history of trephination in Africa with a discussion of its current status and continuing practice.

Trephination of the skull is one of the most fascinating and, certainly, one of the oldest therapeutic procedures known to man. After Prunières' discovery of the trephined skull at Aiguières in 1868, a plethora of information has been gathered about the procedure. There, however, exits little documentation of African trephination or its history. Using both primary and secondary sources, we have discovered that African trephination was known in the time of Herodotus, has a rich history, and is currently practiced widely throughout Africa for specific reasons. We discuss these findings as they relate to preconceived notions of trephinations in other countries and to the history of neurosurgery.

Africa↗
PubMedDate not supplied

Is there a reason for performing frontal sinus trephination at 1 cm from midline? A tomographic study.

UNLABELLED: The complex anatomy of the frontoethmoidal recess, as well as its anatomical relationship with the vital adjacent structures in the region explain the reason for considerable surgical care to protect these structures and minimize complications related to healing. Trephination is an accepted procedure to access the frontal sinus. AIM: Discuss the best location for performing frontal sinus trephination. METHODS: Measuring sinus frontal depth at 3 points equidistant to the midline (crista galli) through the axial tomographic sections. RESULTS: We measured 138 frontal sinus (69 patients). Frontal sinus depth at 0,5 cm was statistically larger than 1 cm and 1.5 cm, as well as the 1 cm trephine point was significantly larger than 1.5 cm (12.22+/-4.25 vs 11.78+/-4.65 p<0,05; 12.22+/-4.25 vs 10.78+/-5.98 p<0.001; 11.78+/-4.65 vs 10.78+/-5.98 p<0.05). The trephine set used (maximum depth of penetration of 0.7 cm) is safe to be applied in approximately 80% of the patients. CONCLUSION: Analyzing the results, the trephination may be performed at variable points of the frontal sinus, but the distance of 1 cm from midline appears to be safer and shows better aesthetic results.

Cohort Studies↗
PubMed1988

Bovine bone morphogenetic protein (bBMP) induced repair of skull trephine defects in sheep.

An aggregate of partially purified bovine bone morphogenetic protein (bBMP) and bone matrix insoluble noncollagenous proteins (iNCP), weighing a total of 100 mg of lyophilized BMP/iNCP, was implanted using ultra thin gelatin capsules in skull trephine defects in adult sheep. One hundred milligram samples of freeze-dried bovine serum albumin (BSA) were similarly implanted for controls. In five sheep, the capsules were implanted in 18-20 mm trephine skull defects and also in posterior cervical muscle pouches for heterotopic controls. In two out of five sheep, the trephines were repaired with bone as early as four weeks after the operation. Eight to 12 weeks after surgery repair was complete in the other three sheep. In the control contralateral trephines, one-third to one-half of the defect was incompletely repaired. Neither the BMP nor the BSA control implants induced bone formation in the muscle. While the BMP/iNCP prepared from bovine bone consistently induced regeneration in skull trephine defects, only fibrous tissue and no extraskeletal bone was induced to form in cervical muscle pouches in sheep.

Animals↗
PubMed1985

Percutaneous trephine biopsy of the vertebral body in the rhesus monkey (Macaca mulatta).

Two methods of percutaneous vertebral body biopsy were performed in the Rhesus monkey, using a 3-mm diameter trephine and a pneumatic driver placed at a 30 degrees angle of approach to the transverse plane of the spine. The freehand method involved placing needle landmarks in the spine, followed by examination of a lateral radiograph of the lumbar region to verify landmark positioning and to estimate placement of the trephine. In the 2nd method, a pneumatic trephine guide was oriented according to a trigonometric calculation based on radiographic data. The pneumatic trephine guide allowed precise placement of the driver and steadied the trephine as it passed through the bone.

Anesthesia, General↗
PubMed1998

Stromal thermal effects induced by nonmechanical (2.94-mum) erbium:YAG laser corneal trephination.

OBJECTIVE: To determine stromal thermal changes after erbium (Er):YAG laser corneal trephination with the use of 2 open masks. METHODS: Corneal trephination was performed in 89 enucleated pig eyes with an Er:YAG laser (400-microsecond pulse duration), 4 open masks (2 metallic and 2 ceramic) for both donors and recipients, and an automated globe rotation device. Different combinations of laser settings were used: pulse energy, 100, 200, and 400 mJ; repetition rate, 2 and 5 Hz; and spot size, 1.3 and 3.2 mm. Thermal effects in corneal stroma and regularity of the cut edges were quantitatively assessed by light microscopy, transmission and scanning electron microscopy. RESULTS: Best regularity and minimal thermal effects of the cut were observed with the use of ceramic masks at 200 mJ, 2 Hz, and 3.2-mm spot size, with middepth thermal changes of 18 +/- 2 microm. Effects increased with cut depth and were lower in donor corneas and with the use of ceramic masks (P<.001). Regularity of the cut was higher in the donors (P = .05) with lower repetition rates (P<.001). CONCLUSIONS: Even with the "free-running" Er:YAG laser mode, features of the trephination cut resembling those created by the 193-nm excimer laser along metal mask were achieved. Ceramic masks may be more suitable than metal masks. The Er:YAG laser seems to have the potential to be a compact and low-cost alternative in nonmechanical trephination for penetrating keratoplasty. CLINICAL RELEVANCE: Thermal effects after corneal trephination with the free-running Er:YAG laser (2.94 mm) are limited and predictable.

Animals↗
PubMed1979

Variation in corneal graft size related to trephine technique.

To determine the range of variation in corneal transplant tissue size induced by slight changes in trephination technique, four human corneas that had been stored in McCarey-Kaufman medium and 11 intact human globes were used. Endothelial surface trephination yielded a smaller corneal button than epithelial trephination. In the intact eye, the higher the intraocular pressure was, the larger the resulting corneal diameter. With use of a trephine with a central plunger, the higher the obturator was, the larger the diameter of the resulting tissue. Also, the duller the trephine was, the larger the diameter of the cut, due to difficulty in tissue penetration. Thus, slight variations can markedly affect the match in size between donor and recipient.

Corneal Transplantation↗
PubMed1989

The Hanna suction punch block and trephine system for penetrating keratoplasty.

We describe a new system for corneal trephination. The system for cutting donor buttons consists of a concave Teflon well in which the donor corneoscleral shell is secured by gentle suction. A cylindrical guide ensures that the disposable razor blade trephine is centered and is perpendicular during punching from the endothelium. The suction mechanical trephine used for the host has the following features: (1) a gun-sight alignment system for reliable centering, (2) a 360 degrees limbal suction ring that secures the trephine to the eye and ensures perpendicularity of the cut, (3) support surfaces on either side of the disposable razor blade that support the cornea during cutting to create near-vertical uniform wound margins, (4) rotation of the trephine with a manually operated gear system for smooth cutting, and (5) a calibration device that governs the extension of the blade and also allows cutting without descent of the blade.

Corneal Transplantation↗
PubMed1992

Photogrammetric analysis of corneal trephination.

We used a high-magnification shadow photogrammetric system to evaluate corneal buttons trephined from human donor globes. Whole eyes were trephined with one of five instruments: nonguarded blades held by hand or placed on a handle, Barraquer-Mateus motorized trephine, Hessberg-Barron suction trephine, or Hanna microkeratotrephine. Corneoscleral buttons were punched with one of three punches: Cottingham, Katena Lieberman guillotine, or a modified Lieberman guillotine with an increased impact force (BPEI 2). The precision (how closely buttons approximated the trephine diameter), accuracy (repeatability), acircularity (deviation from roundness), and straightness (verticality of edges) of cut were calculated from the diameter and edge profile angle measurements of buttons cut by the different instruments. These results were statistically compared. The Hanna microkeratotrephine instrument had the greatest precision and accuracy, least acircularity, and straightest edges. Of the corneal punches evaluated, the Cottingham instrument had the greatest precision; however, the BPEI 2 punch cut with the greatest accuracy and the straightest edges.

Cornea↗
PubMed1986

Effect of trephine tilt on corneal button dimensions.

Wound disparity, mismatch between the size and shape of the donor corneal button and its wound, probably determines the direction and amount of postkeratoplasty astigmatism. Tilting a hand-held trephine is thought to contribute to an oval wound and to wound disparity. We examined the contribution of trephine tilt to wound size and shape. Eyebank eyes were hand trephined at 0, 5, 10, 15, 20, and 25 degrees of tilt. The button endothelial edges were analyzed by the photogrammetric index method. All index values were significantly different from those for a theoretically circular or symmetric button. Although the most oval buttons were at 20 and 25 degrees, buttons were similarly oval and asymmetric for trephine tilt from 0 to 15 degrees. Neither ovality nor asymmetry correlated with angle of tilt. Even when no attempt is made to tilt a hand-held trephine, oval and irregularly shaped wounds may result.

Corneal Transplantation↗
PubMed1999

Three-year clinical outcome after penetrating keratoplasty for keratoconus with the guided trephine system.

PURPOSE: To determine the long-term clinical outcome after keratoplasty with the guided trephine system in keratoconus eyes. METHODS: In a prospective study, all consecutive cases of penetrating keratoplasty had trephination performed with the guided trephine system, with which both donor and recipient cornea are trephined from the epithelial side with a same-sized blade. For wound closure, a double running antitorque suture technique with 10-0 nylon was used. Uncorrected and best-corrected Snellen visual acuity, subjective refraction, and astigmatism by keratometry were evaluated after final suture removal, 2 and 3 years postoperatively. RESULTS: In the 31 patients (31 eyes) enrolled, mean best-corrected visual acuity improved from 0.72 +/- 0.16 (20/30) after final suture removal to 0.88 +/- 0.15 (20/25) 3 years postoperatively (P < .001). The mean spherical equivalent increased from -0.86 +/- 2.10 diopters after final suture removal to -2.35 +/- 2.65 diopters 3 years postoperatively (P < .001). Mean keratometric astigmatism decreased from 4.68 +/- 1.76 diopters after final suture removal to 3.57 +/- 1.37 diopters 3 years postoperatively (P = .001). Furthermore, an increase in mean keratometric levels with time (P = .01) was observed and associated with myopic shift (r(s) = -.46, P = .008). CONCLUSION: With the guided trephine system, we attained favorable visual results, with prolonged improvement of visual acuity during the entire follow-up period. Our data show low and decreasing degrees of corneal astigmatism over time. During the follow-up period, a myopic shift was found after final suture removal. Nevertheless, this technique of performing same-sized grafts reduces postoperative residual myopia.

Adult↗