Updated March 15, 2015 (This supplements the ISASS Policy Statement – Minimally Invasive Sacroiliac Joint Fusion (2014))
A PDF version of the policy statement is available here.
Morgan P. Lorio, MD, FACS
Neuro-Spine Solutions, Bristol, TN
The sacroiliac joint (SIJ) is a cause of chronic lower back pain. SI joints are paired diarthrodial articulations of the sacrum and ilium. The SI joint serves as the biomechanical mediator between the spine and pelvis. The subchondral bone, capsule, and surrounding ligaments of the SIJ are innervated by spinal nerves.(1)
Because SIJ pain can be confused with lumbar and hip pain, proper diagnosis of SIJ pain is key to appropriate patient management. Patients with SIJ pain typically report pain in the buttocks, with possible radiation into the groin or upper legs. Specific physical examination tests that stress the SIJ (e.g., distraction test, compression test, thigh thrust, FABER (Patrick’s) test, Gaenslen’s maneuver, sacral sulcus tenderness) are typically performed in the physician’s office; in combination, these tests are thought to be predictive of SI joint pain.(2) Apart from ankylosing spondylitis, in which MRI can show edema consistent with inflammation, imaging of the SIJ typically does not provide valuable diagnostic information. Rather, imaging is used to ensure that the patient does not have alternative diagnoses that could mimic SIJ pain (e.g., hip osteoarthritis, occasionally L5/S1 spine degeneration). The diagnosis of SIJ pain is confirmed by performing a fluoroscopy guided percutaneous SI joint block with local anesthetic (e.g., lidocaine). An acute reduction in pain of 75%(3,4) (using visual analog scale) or more compared to immediately prior to the block is diagnostic as a positive test and indicates that the injected joint is the pain generator based on published studies. A study of patients undergoing blinded injection of saline or local anesthetic showed markedly high responses to the latter, validating the test.(5) Because other pathologic processes can coexist with SIJ pain, in order to assure that SI joint pain is the primary (or only) diagnosis, the physician should ensure that non-SIJ causes of pelvic or lower back pain are ruled out on the basis of history, physical exam and/or imaging; examples of alternative diagnoses include pelvic fracture, tumor, infection, skeletal deformity, hip arthritis, and degeneration of the L5/S1 disc or other base-of-spine pathologies.
Occasionally, bilateral SIJ pain can occur. Diagnosis of bilateral SI joint pain must be made on the basis of typical history, physical examination showing bilateral SIJ pain with maneuvers (listed above) that stress the SIJ, and bilateral acute pain relief upon bilateral, fluoroscopy-guided SI joint block.
Multiple non-surgical treatments for SIJ pain are available, including pain medications (e.g., non-steroid anti-inflammatory agents, opioids), physical therapy, steroid injections into the SIJ and radiofrequency ablation of the SIJ. Most patients respond adequately to conservative treatment. However, a small number of patients do not have satisfactory pain relief and may be functionally disabled (e.g., cannot sit or stand for more than five minutes, cannot perform normal activities of daily living (ADLs) cannot walk up or down stairs, may require a wheelchair, may require chronic opioid treatment). Patients with a diagnosis of SIJ pain who experience pain for a minimum of six months and who do not respond to an adequate course of non-surgical treatment may be considered for SIJ fusion.
Open fusion of the SIJ can provide pain relief but recovery times are long and the complication rate is high.(6-10) Patients can experience significant intraoperative bleeding and require prolonged postoperative rehabilitation. Therefore, open fusion of the SIJ is best performed on patients who are not candidates for minimally invasive SIJ fusion.(11)
Minimally invasive fusion of the SIJ has been performed with several types of implants, including triangular, porous, titanium coated implants,(8–16) hollow modular screws,(17–19) titanium cages,(18) and allograft dowels(6) (Table 1). These devices are placed either inside or across the SIJ using a minimally invasive surgical approach. Minimally invasive SIJ fusion provides pain relief by acutely stabilizing the painful SI joint with subsequent fusion. In addition to outcomes published of multiple retrospective case series,(8–10,15,21,22) published results from a prospective multicenter randomized controlled trial (RCT) of minimally invasive SIJ fusion vs. non-surgical management (NSM)(14) and a multi-center prospective single arm trial(13) have substantiated high rates of pain relief, improvement in functional measures (SF-36, ODI and EQ-5D) and a low rate of both revisions (<5%) and serious adverse events. Furthermore, these improvements are significantly greater in patients treated with MIS SIJ fusion compared to NSM; VAS scores improved by 53-points in the fusion group compared to 12-points for NSM. ODI improved 30 points in the surgery group vs. 4.9 points in NSM patients, EQ-5D scores improved by 0.29 in the fusion group (p<.0001) vs. 0.05 points in the NSM group. Mean scores for all SF-36 domains improved significantly in the surgery group while no improvement was seen for any domain in the NSM group. Mean SF-36 Physical Component Summary (PCS) improved by 12.7 points in the surgery group vs. 1.2 points in the NSM group. All values were highly statistically significant (p<.0001). In a multicenter retrospective review of 263 patients undergoing either open or minimally invasive SIJ fusion, the latter was associated with statistically significant and clinically marked decreases in operating room time (mean 163 minutes for open vs. 70 minutes for minimally invasive), decreased blood loss (mean 288 cc vs. 33 cc), and decreased length of stay (5.1 vs. 1.3 days) as well as improved relief of pain at 1 (-2.7 points on 0-10 scale vs. -6.2 points) and 2-year (-2.0 vs. -5.6 points) follow-up (all differences are statistically significant.).(11) Two published studies report that favorable outcomes achieved at one year are sustained long term (up to 5-years).(12,16)
The complication rate for minimally invasive SI joint fusion is low. Importantly, the rate of removal or revision is less than 2%. (13,14,23) Revisions can be required in the immediate postoperative period or after many months. Early revisions may include the need to reposition an implant that is impinging on a sacral nerve or removal of an implant due to infection.
In cases of bilateral SI joint pain, bilateral SIJ fusion may occasionally be indicated and is usually performed serially to minimize the impact on rehabilitation (i.e., patients who undergo simultaneous bilateral fusion procedures may be wheelchair or bedbound for several weeks, possible slowing overall recovery).
Patients who have all of the following criteria may be eligible for minimally invasive SIJ fusion:
Minimally invasive SIJ fusion is NOT indicated for patients with the following:
In rare instances, bilateral SIJ pain can occur. Diagnosis of bilateral SI joint pain must be made on the basis of a history of bilateral pain, bilateral elicitation of pain on physical examination maneuvers that stress each SIJ, and acute bilateral decrease in pain upon fluoroscopically-guided intra-articular SI joint block with local anesthetic.
Bilateral SIJ fusion is probably best performed serially to ensure that fusion of both joints is necessary (i.e., pain/disability continues after the first fusion in spite of conservative treatment and a nerve block of the unfused joint results in more than 75% reduction in pain). If bilateral fusion is performed at the same operative session, the surgeon must document both medical necessity and why serial fusion is not indicated in the patient.
It is expected that a person would not undergo more than one SIJ fusion per side per lifetime except in the rare case that a revision is needed.
The American Medical Association recommends minimally invasive SI joint fusion be coded using CPT code 27279. Revision and/or removal of the SI joint implant would typically be coded using 22899 (unlisted procedure, spine) or 27299 (unlisted procedure, pelvis or hip joint) depending on the type of approach and procedure performed, whether within the global period of the fusion, or not.
ICD-9 codes that support medical necessity are shown below.
|720.2||Sacroiliitis not elsewhere classified; inflammation of sacroiliac joint NOS|
|721.3||Lumbosacral spondylosis without myelopathy|
|724.6||Disorders of sacrum|
|739.4||Nonallopathic lesions, not elsewhere classified in the sacral region; sacrococcygeal region or sacroiliac region|
|846.9||Sprains and strains of the sacroiliac region, unspecified site of sacroiliac region|
|847.3||Sprains and strains of sacrum|
For patients undergoing minimally invasive SI joint fusion, the following must be documented in the medical record and available upon request:
Morgan P. Lorio, MD, FACS reports no disclosures.