A comparative study of the optical characteristics of commonly used sinoscopes: do you know where you are looking?

The effect of intranasal irrigation with epinephrine solution on intraoperative visualization and bleeding during FESS

PURPOSE

Bleeding during Functional endoscopic sinus surgery (FESS) can have adverse effect on surgical outcomes. This study evaluates if there is any benefit of adding epinephrine to the saline nasal irrigation in patients undergoing elective FESS for chronic rhinosinusitis.

METHODS

A prospective, randomized, double-blinded study was performed. Fifty ASA I or II patients undergoing FESS were randomized to have irrigation either with normal saline or (1:100,000) epinephrine in normal saline during surgery. Outcomes measure included the Boezaart grading scale to assess the intraoperative surgical field, surgeon's satisfaction with field visualization and bleeding which was evaluated in a 10 cm visual analog scale, estimated blood loss as well as hemodynamic parameters changes.

RESULTS

There was no statistically significant difference in the studied variables between both groups. However in patients with higher than 12 Lund-Mackay score the volume of blood loss was significantly less in the epinephrine group. All surgical procedures were completed and there were no operative complications or any reported perioperative cardiovascular events.

CONCLUSIONS

Intraoperative irrigation with saline-epinephrine solution at a concentration of (1:100,000) is safe and does not change heart rate or blood pressure but is unlikely to improve the setting of intraoperative surgical field except for decreasing the volume of blood loss in patients with high Lund-Mackay score.

An Evaluation of Effect of Pterygopalatine Fossa Injection with Local Anesthetic and Adrenalin in the Control of Nasal Bleeding during Endoscopic Sinus Surgery

Background

The aim of this study was to determine the effect of pterygopalatine fossa infiltration with lidocaine and adrenalin on bleeding in the surgical field during endoscopic sinus surgery.

Methods

A prospective blind randomized controlled trial was performed. Fifty-five patients were randomized to receive a unilateral transoral infiltration of the pterygopalatine fossa with 2 mL of 2% lidocaine and 1:80,000 adrenalin. The operating surgeon was blinded as to which side had been infiltrated at the start of surgery. The surgical field was graded on a previously validated surgical field grading scale every 15 minutes with the side being operated on alternated every 30 minutes. The pulse, mean arterial blood pressure, and end-tidal CO2 concentration were monitored with each surgical field observation.

Results

At each individual time point from 30 minutes to 3.5 hours there was a significant difference in surgical grade between injected and noninjected sides in favor of the injected side (p = 0.01). The difference between surgical grades averaged across all time points was slight but significant. The injected side had an overall mean of 2.59 (SE, 0.22) compared with 2.99 (SE, 0.23) for the noninjected side. Heart rate also was found to correlate independently to surgical grade.

Conclusion

Injection of the pterygopalatine fossa resulted in an improved surgical field during endoscopic sinus surgery.

Defining optical distortion in rigid endoscopes

OBJECTIVES/HYPOTHESIS

To describe lens and perspective distortion using new measures that have practical meaning to the surgeon, and to apply these measures to show the extent of optical distortion in rigid endoscopes used in endoscopic sinus surgery.

STUDY DESIGN

Laboratory measurements on rigid endoscopes.

METHODS

Barrel and perspective distortion were measured in 4-mm diameter 0°, 30°, 45°, and 70° rigid sinus endoscopes. Images of square grids were obtained with the endoscopes aligned in a specially constructed test rig. The terms relative size (RS) and relative distance (RD) were introduced to describe size and distance errors; and the term relative angle (RA) was used for assessing perspective errors.

RESULTS

All the endoscopes exhibited similar barrel distortion. RS of the image at the periphery was 52%; RD was 80%. For RA values of 30°, 45°, and 70°, RS values were 77%, 58%, and 32%, respectively. Objects at the edge of the surgical field appear significantly more distant than suggested by their screen position. Perspective distortion occurs, unless RA = 0°. Barrel distortion of the lens helped to offset the effects of perspective distortion.

CONCLUSION

Optical distortion can be quantified and understood using straightforward definitions. High levels of distortion are common, particularly due to perspective distortion, which is dependent on RA but independent of barrel distortion and the viewing angle of the endoscope.

Measurement of Absolute Dimensions in Endoscopic Sinus Surgery

OBJECTIVE

To develop and evaluate a simple, noninvasive technique for the precise measurement of antrostomy dimensions using standard endoscopic views.

METHODS

We produced an antrostomy probe and devised a method, on the basis of techniques of aerial planimetry, for measuring antrostomies using standardized endoscopic views. Ten shapes of known surface areas were measured independently by three experienced endoscopic sinus surgeons using 30 and 70 degree endoscopes. The accuracies of surgeon assessment and interobserver concordance were calculated.

RESULTS

The three surgeons were able to calculate the surface areas with great precision (Pearson's coefficient of correlation > 0.85 in all cases) using both 30 and 70 degree endoscopes. An intraclass correlation coefficient of 0.92 was obtained, indicating a high degree of concordance between the measurements obtained by different surgeons.

CONCLUSION

This technique shows considerable promise as a tool for precise measurement of antrostomy dimensions in both clinical and research settings.