Paper of the month June 2023 - No. 1

Patient-Reported and Radiographic Outcomes After Revision of Sacroiliac Joint Fusion.
Int J Spine Surg. 2023 Apr;17(2):250-257.
^{Thompson JC, Marigi E, Cross WW 3rd.}

This is the most numerous revision case series after primary SIJ fusion surgery reported by Dr. William Cross, et al.

I like his concept of a surgical procedure based on the principles of arthrodesis in orthopedic surgery, i.e., (1) joint decortication, (2) bone grafting, (3) compression, and (4) rigid internal fixation. The most characteristic feature of this technique is the rigid fixation by a highly skilled trauma surgeon. The technical difficulty of this procedure is unknown.

Followings are my questions to authors of this paper.

1. The operative time and blood loss may vary depending on the condition of each patient, but I wonder how it was in the revision cases.
2. What kind of implants are used in the most difficult revision cases and what anatomical characteristics they have?
3. How long would the surgery take if it were performed as a primary surgery, how much blood loss would occur, and what are the key points of the procedure?
4. What was the history of the cases that led to this revision? Since most of the patients' symptoms improved after the revision surgery, there is no possibility that the cases were misdiagnosed. If this is the case, I would like to know what kind of post-operative care the patients had with their previous surgeons, and what kind of occupations and lifestyles necessitated the revision surgery.

Many of the revision cases were considered to have pseudoarthrosis on imaging in this study.

It is possible that the primary surgery was not strong enough to hold the SIJ in place to control micromotion. Or perhaps the fixation was good initially, but micromotion occurred later and the pain recurred. If the latter is the case, the lack of bone bridging could certainly be considered pseudoarthrosis. However, I thought it might be difficult to determine whether it was pseudarthrosis or not on imaging.

I really think that being able to do these revisions properly is the qualification of a true sacroiliac surgeon. To avoid revision cases, the type of implant used may be related, but it also depends on the quality of the patient's subsequent lifestyle management and rehabilitation (when to start weight bearing, not to allow stair climbing, etc...).

After learning directly from Drs. Sturesson and Kibsgård about postoperative care, I thought that the number of revision cases with them might be low because they are very careful about it.

In 2018, when there was a SIMEG meeting in Tampa, the radiologist who underwent the SIJ fusion surgery was looking for a surgeon who could do a revision. In other words, the surgeon who performed the surgery the first time could not perform the revision. He mentioned that he had seen a CT of his pelvis and that obviously the implants had loosened and his symptoms had returned. That would be a problem. The revision rate after MIS SIJ surgery is not high. However, it is always present. In this paper, Dr. Cross et al. provide an answer as to how we surgeons should handle these cases. I am very grateful to them, and we should make sure that cases requiring revision go through the proper route to his institution and to his colleagues who have mastered this revision technique. Of course, postoperative care should be careful to prevent revision surgery. It will be an important activity of our SIMEG to make this known.

From my own anatomical studies, I have learned that SIJs are structurally stabilized by applying compression. So, I like his surgical concepts. I hope to visit his institution in the near future to see his surgery.

Daisuke Kurosawa