El dolor de la articulación sacroilíaca (SI) puede parecer una ciática, pero su manejo es distinto. Esta guía explica cómo reconocerlo, qué pruebas realmente ayudan, qué tratamientos conservadores funcionan y cuándo valorar procedimientos. Incluye señales de alarma y tiempos de recuperación realistas. Contenido educativo: no sustituye la consulta médica.
What is sacroiliac pain
The sacroiliac joint connects the sacrum to the pelvic bones. It is strong and moves little, but it can become inflamed or degenerate and cause pain in the lower buttock, lumbosacral area, and sometimes the groin. It often appears after repetitive strain, pregnancy, pelvic asymmetries, or after lumbar surgery.
The 7 key points
1. Location is key
Typical sacroiliac pain is centered in the lower buttock and occasionally the groin or the posterior thigh, rarely below the knee. If the pain reaches the foot with tingling or loss of strength, think more of sciatica.
2. Physical tests work as a cluster, not one alone
Provocation tests over the SI joint (for example, pelvic compression–distraction, FABER, Gaenslen) gain value when at least three are positive and the pain is characteristic. A single test does not confirm the diagnosis.
3. Imaging helps to rule out, not to “see” the pain
MRI or CT are used to exclude other causes (herniation, stenosis, fractures, inflammation). A “normal” result does not exclude an SI origin; imaging should be ordered for a reason and only if it will impact management.
4. Diagnostic block is reserved for selected cases
Injecting anesthetic into the SI joint under guidance can support the diagnosis if the pain clearly decreases for hours. It is not mandatory for everyone; consider it when the presentation fits and the therapeutic decision hinges on the result.
5. First, a complete conservative plan for 6–12 weeks
Education and activity, lumbopelvic stabilization exercises (gluteus medius, multifidi, and “core”), judicious analgesia, and physiotherapy as part of a care package. Avoid prolonged rest and chronic opioids. Many people improve with this structured strategy.
6. Procedures: careful indications and realistic expectations
If disabling pain persists after a well-executed conservative plan and the picture is compatible, options such as therapeutic injections, radiofrequency, or minimally invasive sacroiliac fusion may be considered. Randomized trials have shown better results than conservative care in very selected cases, but a recent sham-surgery trial did not show short-term superiority: individualization and clear discussion of benefits and risks are essential.
7. Red flags and when to refer
Refer or go to the emergency department if progressive loss of strength appears, fever with severe pain, saddle anesthesia, or urinary incontinence/retention. If pain limits daily life despite 6–12 weeks of appropriate management, seek specialist evaluation.
Non-surgical treatments
- Adapted activity: stay active, avoid positions that trigger pain, and avoid prolonged rest.
- Guided exercise: progressive strengthening and motor control of the pelvis and trunk.
- Analgesics: short-term acetaminophen/NSAIDs; review risks and avoid chronic opioids.
- Physiotherapy: manual therapy integrated into an exercise and education program, with clear goals and timelines.
- Injections/radiofrequency: temporary relief in selected cases within a comprehensive plan.
Surgical options and risks
Minimally invasive sacroiliac fusion aims to stabilize the joint with implants through small incisions. Possible benefits: reduction of localized pain and better function when standing and walking. Risks: infection, bleeding, thrombosis, nerve injury, implant failure, or persistent pain if other sources coexist (facet joints, disc, hip). Team experience and case selection influence outcomes.
Recovery timelines
With conservative management, improvement usually occurs within 4–8 weeks. After minimally invasive fusion, many people resume basic activities within a few days and sedentary work in 2–4 weeks; physical jobs may require 6–8 weeks or more, depending on individual progress.
When to go to the emergency department
- Sudden or progressive loss of strength in the leg.
- High fever with intense low-back/buttock pain.
- Urinary or bowel changes, saddle anesthesia, severe pain with rapid worsening.
Myths and facts
- “If the buttock hurts, it’s always sciatica”: not necessarily; the SI joint can be the source.
- “A normal MRI rules out the SI joint”: false; the diagnosis is clinical and can be supported by selective blocks.
- “Surgery cures everything”: no; it’s an option only for very specific cases after exhausting conservative measures.
Frequently asked questions
How do I tell sacroiliac pain from sciatica?
Sciatica usually goes below the knee to the foot and may be accompanied by tingling or weakness. Sacroiliac pain concentrates in the buttock/groin and rarely descends past the thigh.
Do I need an MRI to confirm it?
Not always. It is requested to rule out other causes or if the result would change management.
Do injections cure the problem?
They can provide temporary relief and help refine the diagnosis; they are not essential for all patients.
Is sacroiliac fusion definitive?
It is a stabilizing technique that can help in refractory cases, but it is not for everyone and carries risks that must be explained.
Can I play sports?
Yes. Start with low impact and progress according to pain and motor control, preferably with physiotherapy guidance.
When should I book a specialist appointment?
If, after 6–12 weeks of well-delivered conservative management, pain still limits daily life or red flags appear.
Glossary
- Sacroiliac joint (SI): the joint between the sacrum and the pelvis.
- Diagnostic block: injection of anesthetic into the SI joint to identify the pain source.
- Sacroiliac fusion: technique to stabilize the SI joint using implants.
- Cauda equina: bundle of terminal nerve roots whose compression is an emergency.
References
- Dr. Vicenç Gilete – Neurosurgeon. https://complexspineinstitute.com/instituto/#equipo_medico
- Dr. Augusto Covaro – Orthopedic and trauma surgeon. https://complexspineinstitute.com/instituto/#equipo_medico
- NICE. Low back pain and sciatica in over 16s (NG59). 2016, upd. 2020. https://www.nice.org.uk/guidance/ng59
- NASS. Diagnosis and Treatment of Adults with Sacroiliac Joint Pain (protocol). 2023. https://www.spine.org/…/SacroiliacJointPain-Protocol.pdf
- Randers EM et al. MIS sacroiliac fusion vs sham surgery, EClinicalMedicine. 2024. https://www.thelancet.com/…/PIIS2589-5370(24)00017-8
- Polly DW et al. RCT: minimally invasive SI fusion vs conservative management, Neurosurgery. 2015. https://pubmed.ncbi.nlm.nih.gov/26291338/
