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Biomedical subjects

L Daykhovsky

Publications and source records attributed to L Daykhovsky.

At least 19 recordsLinked to original sources

The use of a modular skills center for the maintenance of laparoscopic skills.

BACKGROUND: A reliable method supplying graduated experience and practice is needed to develop and refine laparoscopic skills. The laparoscopic surgeon, like the microvascular surgeon, must have ongoing training to refine and maintain his or her skills. METHODS: The authors describe a new modular training unit. The unit consists of a box with a built-in television camera, a light source, and a rotating platform. A videotape recorder with a timing device documents the actual "operating time" required for the various exercises. The first phase of training consists of a basic skills board. This initial phase enhances the use of dominant and nondominant hand motor activity. RESULTS: The surgeon then progresses to lifelike models (biliary, suturing, hernia, gynecologic) to simulate the human operative setting. Ten surgeons spent 5 h each working with the module. The specific exercises were recorded and timed. Their progress is described. CONCLUSIONS: The modular laparoscopic skills center is an integral part of any laparoscopic educational program. It facilitates the acquisition and maintenance of laparoscopic skills.

Adult

Safety evaluation of laparoscopically applied clips.

We have evaluated in vitro, the security of laparoscopically applied clips, through two commercially available clip appliers: the Endo Clip II (US Surgical) and the Ligaclip (Ethicon). The clip performance was tested with respect to dislodgment and leakage. Dislodgment was attempted both transversely and at 45 degrees with respect to the main axis of the tubular structures tested. The mean maximum force (N = 24) necessary to dislodge a clip applied to silicone tubing (2.1, 2.4, 3.2 mm o.d.) and porcine vascular tissue was measured. The maximum force needed to transversely dislodge a clip applied to silicone tubing, ranged from 262 +/- 9 g (2.1 mm) to 315 +/- 11 g (3.2 mm) for the Endo Clip II applier, while the values for the Ligaclip were 220 +/- 28 g (2.1 mm) and 273 +/- 11 g (3.2 mm), respectively. To achieve dislodgment at 45 degrees pull, corresponding forces of 294 +/- 8 g (2.1 mm) and 369 +/- 14 g (3.2 mm) for the Endo Clip II, and 254 +/- 14 g (2.1 mm) and 297 +/- 13 g (3.2 mm) for the Ligaclip (N = 24) were required. Transverse dislodgment forces, for clips applied to tissue, were 556 +/- 146 g for the Endo Clip II and 356 +/- 170 for the Ligaclip (N = 6). Leakage tests were also performed under pulsatile blood circulation at mean pressure of approximately 800 mm Hg. No tested clips applied to either silicone tubing or tissue allowed for any blood leakage. The dislodgment test showed that the Endo Clip II exhibits superior performance compared to the Ligaclip, based on the fact that it requires more force for transverse and semiaxial dislodgment. In the leakage test, both clip appliers performed equivalently.

Animals

The laparoscopic hernia trainer. The role of a life-like trainer in laparoendoscopic education.

The safe and effective performance of laparoscopic inguinal hernia repair requires a working knowledge of pre-peritoneal anatomy. Most surgeons are unfamiliar with the retro-peritoneal view of the groin. A model has been developed which allows surgeons to learn pre-peritoneal anatomy, to practice laparoscopic inguinal herniorrhaphy and to assess their repairs. This model is a valuable laparoendoscopic educational tool.

General Surgery

Endoscopy of the lacrimal outflow system.

Management of obstructions in the lacrimal drainage system would be greatly aided by improvements in the ability to visualize the blockages. We describe a new method of observation using miniature fiberoptics to view the entire lacrimal excretory system. We employed flexible endoscopes of fiberoptic bundles with outside diameters of from 0.5 to 0.7 mm. These endoscopes were inserted through the puncta and canaliculi. Sixteen patients were examined. A range of pathologic conditions were found, including slightly stenosed passages and severely destroyed canalicular mucosal lining. Our results indicate that this technique is feasible and useful in the diagnosis of lacrimal excretory disease.

Endoscopes

Laparoscopic choledochoscopy: an effective approach to the common duct.

With increasing acceptance of routine cholangiography during laparoscopic cholecystectomy (for confirmation of anatomy) there has been increased identification of common duct calculi. A technique of laparoscopic transcystic common duct stone extraction is described and early clinical results are presented. Successful stone extraction was accomplished in 39 out of 41 consecutive attempts by one surgical team. Two cases required choledochotomy. There were four complications including hyperamylasemia (2), minor wound infection (1), and incidental pneumothorax (1). Recommendations regarding safety and indications are presented. Initial evaluation suggests laparoscopic transcystic stone extraction is safe and effective.

Adolescent

Laparoscopic cholecystectomy in acute cholecystitis.

Between August 1989 and December 1990, twenty-five patients with a preoperative diagnosis of acute cholecystitis underwent laparoscopic cholecystectomy. Twenty-one patients (84%) had abdominal tenderness, 16 (64%) had leukocytosis, and 10 (40%) had fever. Eleven patients (44%) came to the hospital with only one of these previously mentioned clinical signs. Six patients (24%) had two clinical signs. Eight patients (32%) came to the physician with all three findings. The length of surgery correlated directly with the number of presenting clinical signs. The average operating time was 119 minutes. Intraoperative cholangiograms were routinely performed on all patients. Four patients (16%) had common bile duct stones. The average hospitalization was 3.8 days and patients returned to work or routine physical activity between 3 days and 2 weeks (average 8 days) after surgery. There were three wound infections and two cases of hyperamylasemia. One patient developed urinary retention and another had a CO2 embolus. There were no intra-abdominal abscesses and no mortality. Laparoscopic cholecystectomy in acute cholecystitis is technically difficult. The incidence of common bile duct stones is greater than in elective cases, and routine cholangiography is crucial. With sufficient experience and skill, laparoscopic cholecystectomy can be performed safely in patients with acute cholecystitis.

Academic Medical Centers

Biliary calculi fragmentation by a 308 nm excimer laser: a preliminary study.

The use of a 308-nm XeCl excimer laser for biliary stone fragmentation is reported. The 130-nsec laser pulses are delivered via UV grade fused silica fibers to the target stones immersed in normal saline solution and placed in direct contact with the fiber. Sixty biliary calculi, 20 cholesterol and 40 pigment, were fragmented in vitro. The energy delivered per unit mass of the stone is kept constant at 50 mJ/mg. The effect of laser repetition rate, energy fluence, and fiber core size on stone fragmentation was studied. Fragmentation thresholds for a variety of biliary calculi of known composition were measured. It was found that higher fragmentation efficiency was obtained with larger fluence, lower repetition rate, and fiber of larger core. Our study indicates that the 308-nm excimer laser may be effective as a laser lithotriptor with low threshold and good efficiency for biliary stone fragmentation.

Evaluation Studies as Topic

Falloposcopic observations of endotubal isthmic plugs as a cause of reversible obstruction and their histological characterization.

Eighty falloposcopies were performed in fallopian tubes of women with suspected tubal disease. In three falloposcopies (4%), isthmic plugs were observed occluding the entire isthmic lumen. In all cases these plugs were mobilized by falloposcopic-directed, selected tubal cannulation and aquadissection techniques. Restoration of tubal patency, verified by concurrent chromopertubation under laparoscopic monitoring was achieved in all cases. On one occasion, the isthmic plug was mobilized and identified on the fimbria, and tubal patency was confirmed. When this plug was retrieved and examined histologically, it was found to consist of a cast of debris containing aggregates of histiocyticlike cells of endometrial stromal or mesothelial origin. The genesis of these plugs is unknown. In another subgroup, white to yellow mucus like fragments were observed within the intramural and isthmic lumen during a further 8 of 80 falloposcopies (10%). Whether these mucus like fragments are of physiological or pathophysiological significance remains to be determined. Objective demonstration that isthmic plugs can cause reversible proximal tubal obstruction (PTO) has been achieved using falloposcopy. Falloposcopy offers the diagnostician the ability to objectively classify the cause of PTO. A useful falloposcopic classification and scoring system of tubal lumen lesions has been utilized and is described.

Adult

Laparoscopic exploration of the common bile duct: experience in 16 selected patients.

The authors' initial experience with transcystic duct and direct laparoscopic approaches to the exploration of the common bile duct is reported. The technique requires standard laparoscopic equipment, specialized endoscopes, and instruments developed for urologic stone manipulations. After cholangiography confirmed the presence of common bile duct stones, common duct stone extraction was performed in 16 selected patients age 20-88 years. Stones ranged in size from 1 mm to 30 mm and they were unsuspected in 60% of the patients. Five patients had normal liver function tests and only 3 had clinical evidence of jaundice. Ductal exploration and stone extraction was successful in all 16 patients. One patient required a direct laparoscopic ductal exploration due to the presence of a common hepatic duct stone and the anatomy of the cystic duct. No major complications or deaths were observed in this series. Appropriately trained surgeons can safely and effectively perform laparoscopic common bile duct exploration and stone extraction in selected patients.

Adult

Falloposcopic identification of a fimbrio-ovarian mucus connection as a possible mechanism for tubal oocyte capture.

Falloposcopy combined with laparoscopy was performed in 11 women during the late follicular phase of spontaneous menstrual cycles, and a preovular follicle was confirmed to be present in each case. The fimbrial end of the tube and the ipsilateral ovary containing the preovular follicle were suspended in a fluid environment of 200 ml of lactated Ringer's solution which acted as a support medium for visualization of tubal mucus and facilitated the endoscopy procedure. As the falloposcope was passed through the fimbrial opening, it was observed to carry clear, elastic and filamentous strands of mucus material from within the distal tubal lumen in 4 of 11 procedures. As these mucus strands were carried on the tip of the falloposcope to touch the surface of the ovary containing the preovular follicle, they attached, on contact, in all cases. The fimbrio-ovarian mucus bridge created was quite strong and could be stretched for up to 7 mm before it detached from the ovarian surface. The mucus attachment appeared to be equally secure over the preovular follicle and adjacent ovarian surfaces. These fimbrio-ovarian mucus connections, which have a high affinity for ovarian surface attachment about the time of ovulation, may play an important role in securing tubal oocyte capture in humans.

Broad Ligament

Fragmentation of biliary stones with a 308 nm excimer laser.

The use of a XeCl excimer laser (308 nm) for biliary stone fragmentation is reported. Laser energy is delivered via UV grade fused silica fibers to the target stones immersed in normal saline solution. Sixty biliary calculi--pigment (n = 40), and cholesterol (n = 20)--were fragmented in vitro. The total energy delivered per unit mass of the stone is kept constant. Two energy fluences (80 and 110 mJ/mm2) at two repetition rates (5 and 20 Hz) delivered through fibers of two core sizes (300 and 600 microns) are utilized to study the effect of different laser parameters on the fragmentation process. Although both pigment and cholesterol stones are susceptible to excimer laser fragmentation, higher fragmentation efficiency is obtained for the pigment stones than for the cholesterol stones. Our study suggests that higher energy fluence and larger fiber core size result in higher fragmentation efficiency for pigment stones. Fragmentation thresholds at stone surface for a variety of biliary calculi of known composition were measured. The threshold energy fluence is approximately 3 mJ/mm2 and 17 mJ/mm2 for pigment and cholesterol stones, respectively. Our study indicates that the 308 nm excimer laser may be effective as a laser lithotriptor with low threshold and good efficiency for biliary stone fragmentation.

Cholelithiasis

Percutaneous endoscopic laser lithotripsy of retained stones in the left hepatic duct. The role of the surgeon.

A 35-year-old woman with a retained stone in a branch of the left hepatic duct was referred to us. The stone was discovered on the postoperative T-tube cholangiogram. A flexible ureteroscope was introduced into the duct, under fluoroscopic and direct endoscopic vision and the pulse dye laser was used successfully to disintegrate the calculus. The postoperative course was uneventful. We suggest that in certain selected cases, the pulsed dye laser might be useful in disintegrating stones sited in difficult positions.

Adult

Falloposcopy: a microendoscopic technique for visual exploration of the human fallopian tube from the uterotubal ostium to the fimbria using a transvaginal approach.

A transvaginal microendoscopic technique has been developed for safely exploring the human fallopian tube from the utero tubal ostium to the fimbria and adjacent peritoneal cavity. Falloposcopy was performed without complication or evidence of endotubal damage in 44 women, 38 of whom also underwent a concurrent laparoscopy. Eight women with normal tubes served as controls and 36 women with tubal damage underwent falloposcopy in an attempt to document endotubal defects. Previous salpingectomy in 13 women and ostial obstruction in 4 cases left 71 tubes available for falloposcopy. Technical failures, defined as an inability to negotiate the tubal lumen in the absence of obstructive disease occurred in 8 of 71 (11%) procedures. In 63 successful procedures, the tubal lumen was considered to be falloposcopically normal in 28 cases (44%) and contained defects ranging from partial to total obstruction secondary to intraluminal fibrosis within the intramural, isthmic, and ampullary segments in the remaining 35 tubes (56%). Falloposcopy provides a nonincisional modality for defining the normal and abnormal surface anatomy of the tubal epithelium.

Endothelium

Laparoscopic cholecystectomy: instrumentation and technique.

Laparoscopic cholecystectomy is rapidly evolving as a therapeutic modality for the treatment of gallstone disease. The technical details of this procedure and the method by which the gallbladder is dissected and removed are critical to the safe, effective execution of the procedure. Our technique has been developed through extensive practice in porcine models and through experience with more than 250 patients. To perform laparoscopic cholecystectomy we employ a high-resolution video endoscopy system, two high-resolution color monitors, a high-flow CO2 insufflator, a 300 W Xenon light source, electrocautery and/or lasers, and an endoscopic suction-irrigation system. This equipment permits the surgeon to obtain a clear field of view within the abdomen. With these tools, appropriately designed for laparoscopic surgery, including a laparoscope, graspers, dissectors, cholangiography equipment, scissors, and clip appliers, the surgeon can remove the gallbladder without opening the abdomen. The procedure requires the induction of a CO2 pneumoperitoneum, insertion of four trocars, and placement of a grasping retractor to set the operative field. An additional retractor placed on Hartmann's pouch provides countertraction for dissection of the hilum. Careful dissection around the cystic duct and cystic artery with a combination of electrocautery and blunt dissection allows the surgeon to skeletonize the cystic duct and artery. After intraoperative cholangiography confirms the anatomy, the cystic artery and cystic duct are clipped and divided. Electrocautery or laser techniques can be used to perform retrograde dissection of the gallbladder from the liver bed and insure hemostasis. The gallbladder is detached and removed intact through the large trocars. This basic technique can be applied in a wide variety of patients with cholelithiasis. The surgeon proficient in this technique may apply it to a broad range of patients with gallbladder disease.

Cholecystectomy

Development and application of a falloposcope for transvaginal endoscopy of the fallopian tube.

A small flexible microendoscope with an outside diameter (OD) of 0.5 mm has been developed for effective visualization of the entire length of the human fallopian tube. Using a transvaginal approach, a small flexible operating hysteroscope with an OD ranging from 3.3 to 4.5 mm, was used to visualize the uterotubal ostium (UTO) for cannulation of the tube. A coaxial technique, incorporating guidewire cannulation, placement of an "over the wire" Teflon catheter, and replacement of the guidewire with a falloposcope, for video documentation of endotubal surface anatomy has been carried out without complication in 55 women who had a total of 84 tubes available for tubal endoscopy. Characterization of normal and abnormal epithelial changes has been documented for the intramural, isthmic, ampullary, and fimbrial tube. Technical difficulties related to failure to negotiate the entire tubal lumen in the absence of obstructive disease occurred in 9 (11%) of the 84 endoscopy cases. These technical difficulties have been partly overcome by the incorporation of smaller directional guidewires, softer distortion-free Teflon catheters, improved microendoscopes, and the acquisition of new surgical skills necessary for safe and successful endoscopy of the fallopian tube. Minor difficulties were experienced in 7 (8%) of 84 endoscopies due to ostial spasm secondary to attempted guidewire cannulation. Cannulation was successful once spasm ceased. Of the 75 (89%) remaining successful tubal endoscopies, documentation of endotubal lesions ranging from accumulated debris, nonobstructive intraluminal adhesions, stenosis, polyps, to total fibrotic obstruction were observed in 43 (57%) examinations. The majority (70%) of these lesions were confined to the medial third of the tube, between the UTO and ampullary isthmic junction (AIJ). The tubal lumen was considered to be endoscopically normal in 32 (42%) examinations. Techniques of tubal aquadissection (TA), guidewire cannulation (GC), wire guide dilitation, and direct balloon tubuloplasty (DBT) under hysteroscopic-falloposcopic-laparoscopic control were devised for attempting to break down intraluminal adhesions, dilate a stenosis, or open up an obstruction in 35 of the 43 tubes containing a lesion. Combinations of these tubuloplasty techniques were effective for dislodging debris, breaking down adhesions, or dilating stenoses in 16 (58%) of 29 cases and consistently ineffective for bypassing true fibrotic obstructions in 6 (100%) of 6 cases. A detailed description of the falloposcope, its accessory instrumentation, and technique of falloposcopy is outlined. Additionally, preliminary evaluation of falloposcopically directed tuboplasty techniques and their effects on tubal lesions are described. This transvaginal endoscopic technique has been termed falloposcopy and the microendoscopic instrument, a falloposcope.

Adult

The importance of intraoperative cholangiography during laparoscopic cholecystectomy.

Laparoscopic cholecystectomy (LC) using electrocoagulation was successfully performed in 56 out of 58 selected patients. Cholangiography was performed in 53 patients. Six patients had common duct stones; five were unsuspected preoperatively. After the gallbladder was removed, three patients underwent open common duct exploration. In another five cases, anatomical anomalies were discovered. Cholangiography performed via the cystic duct before any structures are divided can prevent the most serious complication--common duct injury. Cholangiography should be attempted on all patients undergoing LC.

Adolescent