In this case the posterior capsule ruptures during hydro-dissection. With a wide open posterior capsule, the nucleus starts to descend into the vitreous cavity. What are the two main options at this point? Option 1 is to let the nucleus descend, clean up the anterior segment and refer the patient to a vitreo-retinal colleague for a full pars plana vitrectomy and lensectomy. Option 2 is the PAL technique which stands for posterior assisted levitation. This is where a needle is inserted via pars plana and it is used to lift the nucleus back up into the anterior segment. This can be successful but it is not without risk.
Click to learn about the PAL technique and to see what I would choose to do: