Final answer:
In medical procedures like egg retrieval, a needle guided by ultrasound is used to open and clean the follicle for aspiration during the LH surge that triggers ovulation.
Step-by-step explanation:
The device used to open the follicle for deeper cleaning in a medical context is typically a needle used for follicular aspiration in assisted reproductive technologies. During an egg retrieval procedure, for example, ultrasound guides the needle to the follicles for aspiration. The LH surge plays a crucial role in leading to the ovulation of the dominant follicle, making it the optimal time for egg retrieval just before this happens.