Mechanical hysteroscopic tissue removal or hysteroscopic morcellator: understanding the past to predict the future. A narrative review.

BACKGROUND: In recent years, the available evidence revealed that mechanical hysteroscopic tissue removal (mHTR) systems represent a safe and effective alternative to conventional operative resectoscopic hysteroscopy to treat a diverse spectrum of intrauterine pathology including endometrial polyps, uterine myomas, removal of placental remnants and to perform targeted endometrial biopsy under direct visualisation. This innovative technology simultaneously cuts and removes the tissue, allowing one to perform the procedure in a safer, faster and more effective way compared to conventional resectoscopic surgery. OBJECTIVE: To review currently available scientific evidence concerning the use of mechanical hysteroscopic morcellators and highlight relevant aspects of the technology. MATERIAL AND METHODS: A narrative review was conducted analysing the available literature regarding hysteroscopic tissue removal systems. MAIN OUTCOME MEASURES: Characteristics of available mHTR systems, procedures they are used for, their performance including safety aspects and their comparison. RESULTS: A total of 7 hysteroscopic morcellators were identified. The diameter of the external sheet ranged from 5.25 to 9.0 mm, optics ranged from 0.8 to 6.3 mm with 0o angle. The cutter device diameter ranged from 2.9 to 4.5 mm most of them with rotation and reciprocation. CONCLUSION: We conclude that the adoption of mHTR has shown to reduce operating time, simultaneously cutting and suctioning tissue fragments avoiding the need for multiple removal and reinsertions of the device into the uterine cavity as well as reducing the volume of distension media required to complete the procedure compared to using the hysteroscopic resectoscope.

Pregnancy related changes of opiate receptors identified in rat uterine membranes by 3H-naloxone binding.

3H-Naloxone was used to demonstrate the presence of specific opiate binding sites in uterine membrane preparations of rats. 3H-Naloxone binding (0.41-27 nM) was found to be rapid, saturable and reversible showing two populations of binding sites with the characteristic of high (KD 2.2 nM; Bmax 46.6 fmol/mg prot.) and low (KD 18.1 nM; Bmax 143.7 fmol/mg prot.) affinity. The number and affinity of the binding sites labelled by 3H-naloxone in the uterus were measured in the rat at mid (14 days), late (21 days) pregnancy and at parturition. The high and low affinity recognition sites labelled by 3H-naloxone showed a consistent reduction during pregnancy and at parturition without changes in the affinity constant. We concluded that pregnancy and parturition are associated with significant changes in the number of the opiate receptors bound in the uterus by 3H-naloxone. This phenomenon which seems to be linked with the several pregnancy-related changes in the levels of endogenous peptides and hormones could be relevant to further explain the pregnancy related changes in pain perception and maternal behavior.

Opioid peptides of the pituitary and hypothalamus: changes in pregnant and lactating rats.

Immunoreactive (Ir) beta-endorphin concentrations were determined in plasma, anterior pituitary (AP), neurointermediate pituitary lobe (NIL) and mediobasal hypothalamus (MBH) of pregnant (12-14 and 18-20 days) and fertile control rats, during labour and lactation. Immunoreactive Met-enkephalin concentrations were also evaluated in the MBH. Concentrations of Ir beta-endorphin in plasma, AP and NIL of rats during early and late pregnancy were significantly higher than in controls, the plasma and AP contents showing an increasing pattern in the second half of gestation. During labour, Ir beta-endorphin concentrations in plasma and AP reached the highest values, whereas those in NIl remained unchanged. Lactating rats showed Ir beta-endorphin concentrations in NIL and plasma in a range similar to that found in pregnant rats, resulting in concentrations in the AP not significantly different from those of nonpregnant controls. Immunoreactive beta-endorphin and Ir Met-enkephalin concentrations in MBH of pregnant rats were almost twice as high as in controls, rising markedly during labour; during lactation levels were in the same range as in non-pregnant controls. These results indicate that pregnancy and labour are characterized by high plasma, pituitary and hypothalamic concentrations of Ir-beta-endorphin as well as by high hypothalamic Ir Met-enkephalin levels, and that Ir beta-endorphin concentrations vary differently during pregnancy, lactation and labour in the two pituitary lobes, supporting the existence of different control mechanisms in the AP and NIL.