Peri-orbital surgical emphysema following endoscopic dacryocystorhinostomy.

BACKGROUND: Peri-orbital surgical emphysema is a rare complication that can occur after lacrimal surgery. It has only been described in isolated cases, following external dacryocystorhinostomy (n = 2) and Lester Jones tube insertion (n = 1). METHOD: A retrospective, non-comparative case series was conducted of patients who developed surgical emphysema following endoscopic dacryocystorhinostomy. RESULTS: A total of 356 endoscopic dacryocystorhinostomy cases (primary, n = 316; revision, n = 40) were performed over a six-year period. Seven cases of post-operative surgical emphysema were identified, all of which were preceded by uncontrolled sneezing, nose-blowing or coughing within the first week of surgery. The occurrence of surgical emphysema post-endoscopic dacryocystorhinostomy in our centre was 7 in 356, or 2 per cent, over six years. CONCLUSION: This is the first study to report the occurrence of surgical emphysema post-endoscopic dacryocystorhinostomy. Clinicians may wish to suggest patients stifle the aforementioned triggers within the first week to reduce the potential for surgical emphysema.

Validation of the second-generation Olympus colonoscopy simulator for skills assessment.

BACKGROUND AND STUDY AIMS: Simulators have potential value in providing objective evidence of technical skill for procedures within medicine. The aim of this study was to determine face and construct validity for the Olympus colonoscopy simulator and to establish which assessment measures map to clinical benchmarks of expertise. PATIENTS AND METHODS: Thirty-four participants were recruited: 10 novices with no prior colonoscopy experience, 13 intermediate (trainee) endoscopists with fewer than 1000 previous colonoscopies, and 11 experienced endoscopists with more than 1000 previous colonoscopies. All participants completed three standardized cases on the simulator and experts gave feedback regarding the realism of the simulator. Forty metrics recorded automatically by the simulator were analyzed for their ability to distinguish between the groups. RESULTS: The simulator discriminated participants by experience level for 22 different parameters. Completion rates were lower for novices than for trainees and experts (37 % vs. 79 % and 88 % respectively, P < 0.001) and both novices and trainees took significantly longer to reach all major landmarks than the experts. Several technical aspects of competency were discriminatory; pushing with an embedded tip ( P = 0.03), correct use of the variable stiffness function ( P = 0.004), number of sigmoid N-loops ( P = 0.02); size of sigmoid N-loops ( P = 0.01), and time to remove alpha loops ( P = 0.004). Out of 10, experts rated the realism of movement at 6.4, force feedback at 6.6, looping at 6.6, and loop resolution at 6.8. CONCLUSIONS: The Olympus colonoscopy simulator has good face validity and excellent construct validity. It provides an objective assessment of colonoscopic skill on multiple measures and benchmarks have been set to allow its use as both a formative and a summative assessment tool.

Development of colonoscopy teaching simulation.

After 17 years of prototyping, a first release version of the St Mark's Hospital teaching simulator is in final preparation. Advances in computer processing power and graphics cards make it possible to achieve real-time processing of colon and endoscope characteristics and a simulated endoscopic view at an acceptable cost. Realistic feel or "force feedback" for all instrument controls and shaft movements is incorporated. To make the simulator more than a "video game", a package of teaching and assessment features is to be incorporated, including interactive animated graphics to explain particular endoscope loops and situations and the variations of colonic anatomy that are typically encountered. Simulation should spare patients from being used for the early phases of training and should speed up and quantify the learning process. Simulators may introduce even experienced endoscopists to some of the advanced options available in current or future endoscopes or accessories, as well as the use of imminent new technology such as the magnetic imaging system.

Accurate PEG tube placement with magnetic positional imaging.

BACKGROUND: Percutaneous endoscopic gastrostomy (PEG) is a common procedure and accounts for an increasing proportion of an endoscopist's workload. Serious complications can occur from inaccurate abdominal wall puncture. Electronic three-dimensional imaging has been used to aid colonoscopy. We adapted the principles of this technique to PEG insertion in a procedure called magnetic positional imaging. METHODS: Magnetic positional imaging was used to determine the abdominal wall puncture site and angle of insertion that would provide the shortest distance from abdominal wall to the stomach. The pull-through technique was used to perform PEG. RESULTS: PEG insertion with magnetic positional imaging was performed on four patients without complications. The average distance between the internal and external sensors was 5 mm. CONCLUSION: A new technique, magnetic positional imaging, facilitates the pull-through technique for PEG. Additional studies are needed to clarify the potential benefit in endoscopic practice.

Depth of insertion at flexible sigmoidoscopy: implications for colorectal cancer screening and instrument design.

BACKGROUND AND STUDY AIMS: The depth of insertion at flexible sigmoidoscopy is variable, depending upon bowel preparation, patient tolerance and distal colonic anatomy. Many endoscopists routinely aim to insert the 60 cm flexible sigmoidoscope to the splenic flexure; however internal endoscopic markers are unreliable, making the true anatomical extent of the examination difficult to assess. The aim of this study was to assess the depth of insertion at flexible sigmoidoscopy. PATIENTS AND METHODS: Two separate studies were done. In the first (study 1), magnetic endoscopic imaging was used to determine the final depth of insertion at non-sedated, screening flexible sigmoidoscopy. In the second (study 2), "real-time" imaging was utilized to determine sigmoid looping and the anatomical location of the endoscope tip after 60 cm of instrument had been inserted during total or limited colonoscopy. A total of 117 consecutive average-risk patients, aged 55-65 years participated in study 1, and 136 patients underwent either limited, (33) or attempted total colonoscopy (103) in study 2. RESULTS: In study 1 the median insertion distance was 52 cm, range 20-58. In 61 % of patients the imaging system showed that the descending colon had not been visualized by the end of the procedure. Failure to reach the sigmoid/descending junction occurred in 29 (24%) patients. Reasons for failure included poor tolerance of the procedure due to pain (23 patients) inadequate preparation (3 patients) and, excessive looping (3 patients). In study 2, after 60 cm of instrument had been inserted, the splenic flexure or beyond was reached in 29% and the descending colon in 9%, whilst in 62 % the endoscope tip had not passed beyond the sigmoid/descending colon junction. A sigmoid loop formed in 70% of patients, and unusual loops such as the alpha, reverse alpha and reverse sigmoid spiral loop occurred more frequently in women compared to men (P = 0.0249). In those 104 patients where the splenic flexure was reached the mean maximum length of instrument inserted prior to reaching the flexure was 75.4 cm, (SD = 21.9). CONCLUSIONS: Examination of the entire sigmoid was not achieved in approximately one-quarter of patients undergoing screening flexible sigmoidoscopy, mainly because of discomfort. The descending colon is intubated in a minority of cases (using standard instruments), even after 60 cm has been inserted. Alternative instruments with different shaft characteristics (floppy, narrow calibre, 80-100 cm in length) may be necessary to ensure deeper routine intubation in nonsedated patients.

Real-time magnetic three-dimensional imaging of flexible endoscopy.

Because of the variability of the colonic anatomy from patient to patient, colonoscopy may be technically difficult to perform and teach, and lesions may be localized inaccurately by the endoscopist. Endoscopists understandably have abandoned fluoroscopy as an adjunct because of its expense, complexity, and potential hazard. The authors have developed a novel method of magnetic imaging that gives real-time views in simulated three dimensions of the endoscope configuration and the location of its tip in the abdomen. The system is inherently safe and easy to use, although it currently requires a catheter to be inserted into the instrumentation channel. Preliminary experience suggests that this approach will be a significant help to endoscopists performing colonoscopy, particularly to those who are currently learning or less experienced.

First clinical results with a real time, electronic imager as an aid to colonoscopy.

The early clinical results are described of a real time, electromagnetic imaging system as an aid to colonoscopy. After gaining experience with the use of the system, one experienced endoscopist was randomised to perform consecutive colonoscopies either with (n = 29) or without (n = 26) the imager view. All procedures were recorded on computer disk and replayed for retrospective analysis. Total colonoscopy was achieved in all patients except one (imager view not available). Comparing intubation time and duration of loop formation per patient, there was no significant difference between the two study groups. The number of attempts taken to straighten the colonoscope pre patient, however, was less when the endoscopist was able to see the imager view, p = 0.03. Hand pressure was also more effective when the endoscopist and endoscopy assistant could see the imager display, p = 0.02. Preliminary experience suggests that real time, electronic imaging of colonoscopy is safe, effective, and will improve the accuracy of the procedure.

Non-radiological technique for three-dimensional imaging of endoscopes.

A novel system is described which images in three dimensions, the total configuration of a colonoscope without the use of conventional radiological techniques. A low intensity magnetic field is used in conjunction with a miniature inductive sensor. The system intrinsically safe and it is potentially inexpensive and capable of being used in a normal hospital environment. Clinical trials are described in which the system is validated in terms of its suitability for the application. Magnetic and conventional X-ray images obtained ex vivo with the endoscope held in various configurations and comparisons in the patients confirm the practical applicability of the new system.