Sacroiliac Joint Fusion Indications and Techniques

The sacroiliac joint (SIJ) is an often-overlooked source of low back pain that can radiate to the buttock, groin, or lower extremity. ¹^, ²^, ³ A series of 200 consecutive new patients with low back pain and no history of spine, SIJ, or hip surgery were examined in a spine surgery clinic. The cause of pain was lumbar in 65%, SIJ in 5%, and both lumbar and SIJ in 14.5%. ⁴ SIJ pain impact is similar to other surgically treated conditions such as spinal stenosis, degenerative spondylolisthesis, and hip osteoarthritis, and the burden of SIJ pain is higher than many commonly disabling medical conditions such as chronic obstructive pulmonary disease and angina. ⁵ There is significant annual direct medical cost associated with nonsurgical management of SIJ dysfunction in the Medicare and commercial insurer populations. ⁶^, ⁷

Level 1 evidence from a multicenter prospective, randomized, controlled trial has shown superiority of minimally invasive SIJ fusion compared with nonsurgical management for patients with SIJ dysfunction at 6 months ⁸ and 12 months of follow-up. ⁹ Several retrospective cohort studies have shown benefit as long as 5 years after SIJ fusion. ¹⁰^, ¹¹^, ¹²

The SIJ articular surface contains both nociceptive and mechanoreceptors, ¹³^, ¹⁴ with innervation from lateral branches of the dorsal rami as well as ventral rami from L5–S4. ¹⁵^, ¹⁶ Because SIJ dysfunction can closely mimic mechanical low back pain, lumbosacral radiculopathy, or hip arthropathy, clinicians must diligently perform a targeted physical examination to directly stress the SIJ.

55.2 Patient Selection

A combination of targeted SIJ physical examination maneuvers and image-guided SIJ injection is the gold standard for diagnosing SIJ dysfunction. ¹⁷

55.2.1 Clinical Examination

In the standing position, the patient is asked to point to the greatest site of pain (Fortin Finger test). The posterior superior iliac spine (PSIS) is then evaluated for point tenderness to palpation.

A series of six SIJ diagnostic examination maneuvers are then performed, as described previously. ¹⁷ Although these maneuvers may cause discomfort in multiple areas, it is crucial to instruct the patient to report specifically whether each maneuver reproduces the exact type of typical pain that is his or her initial complaint. The patient lies supine on the examination table and pelvic gapping, flexion–abduction/external rotation, and thigh thrust maneuvers are performed ( ▶ Fig. 55.1). The patient is placed in lateral position for Gaenslen’s maneuver and pelvic compression, performed on each side. Sacral thrust is then performed with the patient prone. A full examination of the lumbosacral spine, lower extremity, and hip is also performed.

Fig. 55.1 Sacroiliac joint provocative physical exam maneuvers. (a) Pelvic gapping. (b) Flexion, abduction, external rotation (FABER/Patrick’s). (c) Thigh thrust. (d) Compression. (e) Gaenslen’s. (f) Sacral thrust. Reproduced with permission from Sembrano J, Reiley M, Polly D, et al. Diagnosis and treatment of sacroiliac joint pain. Curr Orthop Pract 2011;22:345.

A minimum of three SIJ physical examination maneuvers must be positive for re-creation of the patient’s pain to proceed with further diagnostic workup for SIJ dysfunction. ¹⁸ Clinical examination maneuvers targeting the SIJ are paramount in detecting SIJ dysfunction but are not sufficient alone to make the diagnosis. ¹⁹^, ²⁰^, ²¹

55.2.2 Radiographic Evaluation

Patients with significant SIJ pathology on clinical examination undergo anteroposterior (AP), lateral, and Ferguson plain radiographs of the pelvis evaluating for alternative diagnoses that can mimic SIJ pain, such as hip osteoarthritis or lumbosacral degenerative disease. Imaging alone has not been shown to predict SIJ symptoms.

55.2.3 Diagnostic Injection

Patients with three or more positive physical examination findings next receive a diagnostic injection of local anesthetic into the SIJ by a qualified radiologist or interventional specialist. Injection is with lidocaine only, not steroid medication, and is performed with contrast visualization of injection location under fluoroscopy. The patient is instructed to record pain response to typically provocative painful movements in the 1 to 2 hours after the injection. A 50% relief of pain is considered significant. It is optimal to personally review the fluoroscopy image from the injection to ensure desired targeting of lidocaine into the SIJ. If question exists about localization of medication, we repeat the diagnostic injection of the SIJ using computed tomography (CT) guidance, again with local anesthetic only. If a patient does not report at least 50% pain relief, SIJ dysfunction is unlikely to be the cause of the symptoms or is unlikely to be responsive to surgical intervention.

55.2.4 Nonsurgical Management

Patients are sent for directed SIJ physical therapy (PT) by a therapist specifically skilled in SIJ PT. Adequacy of the physical therapy intervention is typically assessed by the therapist. Sacroiliac belts may be used as an additional therapy adjunct. If PT, lifestyle modifications, and nonsteroidal anti-inflammatory medications fail to control symptoms, a therapeutic SIJ injection with local anesthetic and steroid medication is performed. ²² Significant pain relief for up to 2 years after such injections has been reported. ²³ If the patient receives long-lasting relief from this, the injection can be repeated; however, if the patient has repeated return of significant pain despite technically adequate SIJ injection, then the patient may be considered for radiofrequency ablation (RFA) or for SIJ fusion. Because of the individual anatomic variability in SIJ innervation, RFA is technically difficult to perform and has typically been associated with only short-term symptom relief, ²⁴^, ²⁵ although long-term relief has recently been reported. ²⁶

55.2.5 Surgical Management

Fusion of the SIJ can be performed via open anterior, open posterior, or minimally invasive (MIS) lateral approaches. SIJ fusion was first described via an open approach in the 1920s. ²⁷ Despite several modifications to technique, the open approach for SIJ fusion has been typically associated with substantial pain, blood loss, and prolonged recovery periods resulting from extensive soft tissue dissection as well as nonunion rates varying from 9 to 41%. ²⁸^, ²⁹^, ³⁰ Consequently, open SIJ fusion has widely variable patient satisfaction rates as well as serious complication rates as high as 13.7%. ³¹

MIS SIJ fusion leads to clinically and statistically significant improvements in back pain, function, and health-related quality of life with high patient satisfaction and low complication rates. ⁸^, ¹⁰^, ¹¹^, ³²^, ³³^, ³⁴ Level 1 evidence has demonstrated safety and effectiveness of MIS SIJ fusion. ⁸ In this prospective randomized, controlled trial of 148 patients with SIJ dysfunction comparing nonsurgical management to MIS SIJ fusion, 75% of the MIS SIJ fusion cohort showed a clinically significant improvement in Oswestry Disability Index compared with 27% of the nonsurgical management cohort at 6-month follow-up. The trend continues at 12 months of follow-up, with a significant number of patients benefitting from MIS SIJ fusion compared with nonsurgical management. ⁹

MIS SIJ fusion can have consistent and durable results at 5 years. Compared with open SIJ fusion, MIS SIJ fusion has higher rate of clinical success, no need for bone graft harvesting, faster postoperative mobilization, shorter hospital length of stay, and fewer complications. ³³^, ³⁵^, ³⁶ MIS SIJ can be performed as an outpatient procedure in appropriately selected patients.

55.3 Preoperative Preparation

Once a patient has been determined to be a potential surgical candidate, noncontrast CT scan of the pelvis is obtained to evaluate sacroiliac anatomy for feasibility of implant placement. The patient attends a preoperative PT teaching session for crutches modality training for toe-touch weight-bearing.

55.4 Operative Procedure

55.4.1 Minimally Invasive SIJ Fusion

MIS SIJ fusion is performed with the patient under general anesthesia. The patient is positioned prone with hips and knees extended on a radiolucent table using either fluoroscopic guidance with AP and lateral images, or three-dimensional computer navigation based on intraoperative CT scan, as previously described. ⁸^, ³⁶ Once imaging has been used to determine a starting point on the lateral gluteal region ( ▶ Fig. 55.1 a), the skin is infiltrated with local anesthetic and a 3- to 5-cm incision is made in the skin and fascia with dissection carried down to the ilium. Using image guidance, a Kirschner (K-wire) is placed across the SIJ into the sacrum, exercising vigilance to remain lateral to the neuroforamina. Fluoroscopy is used to check location. Implant length is determined. Cannulated serial dilators are used for the soft tissue envelope. After drilling a pilot hole with a cannulated drill bit, a cannulated broach is malleted across the SIJ, taking care not to advance the K-wire ( ▶ Fig. 55.2 b). The implant is then manually inserted. Fluoroscopy is used to check location. This process is repeated for a typical total of three implants. Intraoperative CT scan is used to check final implant location ( ▶ Fig. 55.2 c). The wound is irrigated and closed. Other techniques using screw-in type devices with or without fenestrations are available as well.

Fig. 55.2 Minimally-invasive sacroiliac joint (MIS SIJ) fusion. (a) Intraoperative real-time three-dimensional computed tomography–based navigation of percutaneous implant placement across the SIJ. (b) Intraoperative planning of implant trajectories and subsequent navigated placement. (c) Intraoperative CT scan (using O-arm) of the SIJ to assess implant placement. (d) Postoperative radiographs of the pelvis with three fusion rods across the SIJ.

Only gold members can continue reading. Log In or Register to continue