SI Joint Fusion

You may be a candidate if SI joint pain has limited your daily life for at least six months despite intensive physical therapy, medicines and activity changes, and image-guided numbing injections into the joint relieved at least 75% of your pain^[1]. Imaging should rule out problems in the lower spine and hip. People with widespread pain conditions, or whose pain was not clearly relieved by injections, are usually not good candidates.

Plan for a few weeks of limited activity. Bring your imaging and injection records and a full list of medicines and supplements. Many blood thinners need to be paused for a set time before surgery^[10], but never stop one without approval from the doctor who prescribed it. Stopping nicotine helps bone heal. Arrange a ride home, help for the first few days and a walker or cane.

The operation itself usually takes about an hour^[8], and you can expect to spend a few more hours at the surgery center for check-in, anesthesia and recovery. It is usually done as an outpatient procedure, so most people go home the same day. Some people, especially when both sides are treated or there are other health concerns, stay overnight.

Most people have soreness in the buttock and at the incision for the first one to two weeks, managed with ice, short-term pain medicine and gradual walking. Because the incisions are small and muscles are not cut away from the spine, recovery is usually easier than after open spinal fusion. Pain that does not improve, or that returns along with swelling and warmth near the joint, should be checked^[8].

Early restrictions are temporary: limit weight on the treated side with a walker or cane, avoid lifting more than 10 pounds and avoid sitting longer than 45 minutes at a time^[8]. Driving is usually avoided for at least a few weeks^[8]. Most people resume their usual physical activities about three to four months after surgery^[8]. Your surgeon will tell you whether any longer-term limits apply to you.

Usually very little that you notice in daily life. The SI joint normally moves only slightly, so fusing it does not stop you from bending, walking or turning. Because two bones are joined, the joint may not move as freely, and some people notice lasting stiffness^[8]. Your lower back and hips continue to provide most of your movement.

Lateral fusion places implants from the side of the pelvis across the joint and is the most studied approach, with two randomized trials^[4][5]. Posterior fusion places bone graft or an implant into the back of the joint, can be done through a very small incision and sometimes with sedation, but its evidence comes mainly from uncontrolled studies^[7]. Coverage can also differ by approach^[2].

For carefully selected patients, lateral fusion has produced larger improvements than nonsurgical care in randomized trials. In one trial, average pain improved by 45 points on a 100-point scale at two years after fusion, compared with 11 points with conservative care^[5]. Results depend heavily on an accurate diagnosis, and not everyone gets lasting relief.

Possible problems include infection, bleeding, anesthesia reactions, nerve irritation from an implant, failure of the joint to fuse and, rarely, new pain elsewhere in the back^[8]. In one randomized trial, 3 of 102 patients needed revision surgery within two years^[4]. We review your personal risk factors, such as bone density and smoking, before recommending surgery.

Medicare’s local policy for New York (LCD L36406) covers minimally invasive SI joint fusion when all criteria are met, including six months of intensive nonsurgical care, at least 75% relief from diagnostic injections and specific imaging^[1]. New York workers’ compensation requires pre-authorization and sets similar criteria, including requirements about the surgeon’s training, which our physicians meet^[3]. Commercial plans usually require prior authorization, and some limit coverage for posterior graft-only techniques. No-fault follows its own rules. We verify your benefits first.

Physical therapy focused on the pelvis and hips, a pelvic belt, anti-inflammatory medicines and steroid SI joint injections help many people. If injections help only briefly, lateral branch blocks followed by SI joint radiofrequency ablation can quiet the nerves to the joint for months. Fusion is usually reserved for pain that persists after these options.

Walking is generally helpful. Before surgery, an active exercise program, which can include walking, is part of the conservative care Medicare expects you to try first^[1]. After fusion, you start walking right away, using a walker or cane at first to protect the healing joint^[8]. If walking makes your pain much worse, slow down and tell your physician or therapist.