Minimally invasive surgery lateral percutaneous sacroiliac joint fusion in a patient with radicular-type pain: case report and review of the literature

Introduction

Sacroiliac (SI) joint pain is a common cause of low back and buttock pain. Less commonly, SI joint pain can also present with thigh and leg pain in a radicular distribution (1). The diagnosis involves a comprehensive history, physical exam including provocative maneuvers, imaging such as plain radiographs, magnetic resonance imaging (MRI), computed tomography (CT), and single photon emission computed tomography scan with computed tomography (SPECT/CT) to evaluate the SI joint and to rule out other causes of pain (1). Here, we report a case of a woman with severe left-sided lower extremity radicular-type pain who underwent successful minimally invasive surgery (MIS) lateral percutaneous SI joint fusion. This case is illustrative of the variable clinical presentation of SI joint dysfunction and the importance of a thorough diagnostic evaluation in patients with low back pain. We present this case in accordance with the CARE reporting checklist (available at https://jss.amegroups.com/article/view/10.21037/jss-24-93/rc).

Case presentation

A 76-year-old woman with no significant medical or surgical history presented to the clinic with one year of progressive left-sided low back pain which radiated to the back, buttock, leg, and heel. Initially her pain was worse in the morning and while sitting but improved with ambulation, laying down, and heat applied over her back. Over time, her pain became debilitating and she was unable to participate in many activities of daily living. She had previously received medial branch blocks at L3, L4, L5, and S1 with a transient, only partial improvement in pain. A second medial branch block did not improve her pain.

On physical examination, she had normal strength to confrontation, normal sensation to light touch, and proprioception. She had a positive left-sided Flexion, Abduction and External Rotation (FABER or Patrick’s) test, positive left-sided thigh thrust, and positive Gaenslen. She also had tenderness over the posterior superior iliac spine (positive Fortin Finger Test).

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Diagnostic workup

Preoperative radiographs and CT demonstrated bilateral SI joint degeneration (Figure 1). MRI lumbar spine demonstrated no significant central or foraminal stenosis. There was evidence of mild bilateral L3/4 and L4/5 lateral recess stenosis and multilevel degenerative disc disease. SPECT/CT demonstrated increased radiotracer uptake throughout the lumbar spine and bilateral sacroiliac joints but the distribution was symmetric across the joints (Figure 2). Full-length plain radiographs demonstrated no global imbalance, focal listhesis, or instability.

Figure 1 Preoperative AP radiograph with evidence of bilateral SI joint degeneration (patient left side on left side of radiograph), coronal CT and axial CT demonstrating SI joint degeneration with osteophyte formation, joint space narrowing and vacuum phenomenon. AP, anteroposterior; SI, sacroiliac; CT, computed tomography.

Figure 2 Negative SPECT/CT scan with diffuse radiotracer uptake throughout the lumbosacral region indicative of a non-specific negative SPECT/CT scan. SPECT/CT, single photon emission computed tomography scan with computed tomography.

She underwent lower extremity electromyography (EMG) which demonstrated no evidence of lumbosacral radiculopathy or peripheral neuropathy. SI joint injection was performed twice under fluoroscopic guidance. She reported complete pain resolution for roughly 5 hours after the injections. Given her positive physical exam findings and positive response to two consecutive SI joint injections, it was determined that her SI joint was the primary pain generator.

She was referred for physical therapy evaluation and was compliant with core exercises and postural correction but her pain continued to progress.

Surgical intervention and short-term outcome

After the failure of conservative treatment, the risks and benefits of surgery were discussed. A bone density (dual-energy X-ray absorptiometry) examination was obtained and revealed no osteoporosis. She underwent an MIS lateral percutaneous SI joint fusion. After induction of general anesthesia, prone positioning on an open bottom Jackson table, prepping, and draping, a stereotactic reference frame was placed into the left iliac bone. After an intraoperative 3D image was obtained, three screw trajectories were planned. The first screw was planned 1 cm distal to the alar and sacral line intersection. The second was planned at the level of the S1 foramen and the third at the level of the S2 body. A 3-cm incision was made in line with the three trajectories. A navigated universal drill guide was used to place an O-arm pin traversing the SI joint, to the depth of the planned screw trajectory. A blunt dissector was first advanced over the pin. Then, an initial dilator was advanced over which a tubular retractor is docked to the bone. A drill and tap were used before placement of the fenestrated screws (iFuse-TORQ, SI Bone, Santa Clara, CA, USA). The screws were backfilled with demineralized bone matrix. Screw placement was confirmed with an intraoperative CT and imaged postoperatively with standard X-ray (Figure 3).

Figure 3 Postoperative lumbar radiograph following MIS lateral percutaneous SI joint fusion, a post-operative X-ray image is shown in the coronal and sagittal views verifying intended placement of 3 fenestrated screws. MIS, minimally invasive surgery; SI, sacroiliac.

The patient reported complete pain resolution at 6 weeks and 5 months postoperatively. She has returned to her baseline activities.

Discussion

The SI joint is an axial diarthrodial synovial joint that has been identified as a cause of pain for an estimated 10–25% of patients dealing with low back pain or radicular leg pain (2). Due to the varied etiological causes of SI joint pain, both the diagnosis and subsequent treatment continue to present challenges for clinicians and patients alike. Previous studies have aimed to address the diagnostic complexities of SI joint pain and its variable clinical presentation (2-6). However, a single diagnostic test or pathognomonic provocative maneuver eludes us at this time. Studies conducted by van der Wurff et al., Telli et al. and Young et al. showed that a positive response to at least three provocation tests (Thigh thrust, Compression test, FABER test, Gaenslen’s maneuver, Distraction test) can be considered reliable to make the diagnosis of SI joint pain (5-7). Thawrani et al. advocate for a combination of at least 3 positive provocative tests before administering diagnostic SI joint injections. Following an SI joint injection a reduction of approximately 75% of pain strongly suggests the diagnosis of SI joint dysfunction (2).

Research has also been conducted to investigate the clinical utility of radiographic imaging and bone scanning in the diagnostic work-up of SI joint pain. Due to the complex anatomy of the SI joint and the high prevalence of SI joint degeneration in asymptomatic patients, traditional imaging modalities such as radiographs, CT, and MRIs are often unhelpful (8,9). SPECT/CT is a relatively less common imaging modality that combines the sensitivity of SPECT with the anatomic specificity of CT. These scans can be used to identify areas of increased osteoblast remodeling activity which can be used as a proxy for sites of increased bony inflammation. Much of the existing literature supports the ability of SPECT/CT to localize primary pain generators in the cervical and lumbar spine (10-12). Few studies have characterized SPECT/CT for diagnosing SI joint pathology and the evidence has been promising albeit limited (13,14). Tofuku et al. evaluated patients in a Japanese cohort with positive SIJ joint injections and observed radiotracer accumulation in the SI joint in all patients. Cusi and authors relied on the clinical diagnosis of SI joint dysfunction for enrollment and similarly found a high rate of radiotracer accumulation in the joint.

We present a case of a patient with atypical radicular-type pain and diffuse radiotracer uptake throughout the lumbosacral spine and sacroiliac joints on SPECT/CT imaging suggestive of a non-specific scan. After (I) several positive provocative tests and (II) 2 diagnostic SI joint injections were performed providing complete pain relief for several hours, it was determined that the patient’s radicular-type pain was likely originating from the SI joint. Afterwards, the patient was offered an MIS lateral SI joint fusion procedure for long-term management of her symptoms. Since the procedure, the patient has had total resolution of their debilitating radicular-type pain and continues to report being asymptomatic at the 6-week and 5-month follow-up visits. This case highlights the variability of sacroiliac joint pain presentations as well as the potential lack of to sensitivity of SPECT/CT scans in diagnosing SI joint pain. This supports the need for futher prospective study.

Conclusions

A high index of suspicion for SI joint dysfunction must be maintained for all patients with low back and radicular-type pain. Provocative physical exam maneuvers are the cornerstone of initial diagnosis, followed by SI joint injections. Plain radiographs and CT imaging demonstrate signs of sacroiliac degeneration MRI lumbar spine imaging is helpful to exclude other lumbar spine pain generators. SPECT/CT is a potentially powerful diagnostic tool, particularly in patients with multiple possible pain generators, but the sensitivity for SI joint dysfunction may be more variable in different populations and requires further investigation.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://jss.amegroups.com/article/view/10.21037/jss-24-93/rc

Peer Review File: Available at https://jss.amegroups.com/article/view/10.21037/jss-24-93/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jss.amegroups.com/article/view/10.21037/jss-24-93/coif). D.C. serves as an unpaid editorial board member of Journal of Spine Surgery from December 2022 to November 2024. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for the publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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