What are the chances of muscle spasms/pain with butt implants and are they less common intramuscularly?

Fortunately, true direct nerve damage, in particular to the sciatic nerve, is quite rare after buttock implants. And when performed by a reputable and experienced buttock implant specialist, this type of nerve damage is almost unheard of and likely has a incidence rate of less than 0.1%. Now, for the absolute best long term outcomes, buttock implants are best placed intramuscular. If not, the risk of visibility, sagging, implant rotation or flipping, or capsular contracture is much much greater. However when buttock implants are placed intramuscular there of course is more swelling to the muscles and then muscle spasm against the implant. This creates short term and expected symptoms such as muscle cramps and indirect pressure on the sciatic nerve which can lead to some shooting pains in the butt, into the back of the thigh and/or legs. But again, if the surgery is performed by a specialist these postoperative symptoms are short-lived - as the swelling resolves and the muscles relax and stretch a bit, the shooting pains typically resolve within two weeks to two months. Thus the risk of long-term pain from either indirect sciatic nerve compression and/or implant tightness within the buttock compartment is ~0.5%. Glad to be of help. Note, these statistics are based off of my personal 20 year experience.

The size and placement of the implant has a lot to do with possible complications. The key to this surgery is to select an implant that is not so large that the muscle cannot cover it reliably. You want a nice result, but you want to avoid the complications (need for removal, infection, extrusion, fluid collection, implant migration, implant visibility, and capsular contracture among others).
Studies have demonstrated that sizes above 350 cc have a greater rate of complications, but most women choose an implant volume in the 350cc to 400cc range. The intramuscular placement also reduces the risk for capsular contracture and sciatic nerve damage.

Hello. In my experience of 29-year practice I decided not to placed butt implants any more. They are placed under the muscles in a plane created by the surgeon. The complications are many : dispalcement, migration, pain, not being able to have injections on the buttocks, etc. All the patients decide to take them out at the end of a painful journey. Fat transfer is always the best option.Good luck