Unlike the monoclinic form, orthorhombic paracetamol is suitable for the direct compression process. The crystalline structure accounts for its better compression behavior, because of the presence of sliding planes.

Background: Office hysteroscopy is an affordable and popular approach in gynecology, offering high quality and inexpensive care. It has been made possible by miniaturization of instruments along with a range of technical variations and innovations which have made the procedure tolerable in outpatient care units. Pain is still a problem and has not to date been adequately managed.Objectives: Our main objective is to compare two centers where hysteroscopy is performed without general anesthesia or sedation in an office setting. In Lisbon a novel local anesthetic technique has been introduced when patients complained of pain. These centres have slightly different protocols namely in assessing pain and evaluating score results. Materials and methods:This was a prospective observation multicenter study, comparing pain in office hysteroscopy with three groups: mini-hysteroscopy (3 mm scope), conventional (5 mm) hysteroscopy without anesthesia and (5 mm) hysteroscopy with "hysteroscopic anesthesia". Data collection and analysis:We analyzed data from two centers involving one hundred and eighty one participants who completed the intervention. Pain was evaluated using a 10 cm visual analogue scale and a numeric rating scale. Analysis included the Kruskal-Wallis and Mann-Whitney Tests for the three groups and the Wilcoxon Signed Ranks Test for comparing repeated measurements. Results were discussed at 5% significance level.Main results: Analysis revealed a significant reduction pain score (p value <0.001) in the group where "hysteroscopic anesthesia" was used.Conclusions: Pain scores in office hysteroscopy can be lowered with "hysteroscopic anesthesia".