Sacroiliac Joint Syndrome: What to Suspect When Only One Side of the Sacral Area Keeps Aching After Disc Treatment

Last updated: 2026-09-30

My Leg Numbness Has Eased, but One Side of My Sacral Area Keeps Aching

If treatment for a herniated disc (the cushion between the vertebrae) or spinal stenosis has eased your leg numbness, but one side of your sacral area (where the lower back meets the buttock) keeps aching when you sit down and stand up, you are a candidate for having the sacroiliac joint — which bears body weight at the back of the pelvis — evaluated as a possible cause of the remaining pain.

The sacroiliac joint refers collectively to the joint connecting the sacrum and the ilium at the back of the pelvis, along with the surrounding ligaments. It is the key junction that transfers the weight of the upper body, carried down through the spine, through the pelvis to both legs. This joint withstands the strong torsion and shear forces generated during walking or twisting the body, and maintains the stability of the entire pelvis (Gartenberg A et al., 2021).

Pain that arises when this joint and its surrounding ligaments are subjected to sustained excessive load or develop inflammation is called sacroiliac joint syndrome.

When a Herniated Disc and Sacroiliac Joint Syndrome Occur Together in the Same Patient

A herniated disc (the cushion between the vertebrae) or spinal stenosis can occur together with sacroiliac joint pain in the same patient. When injection treatment first relieves the radiating pain caused by compression of the spinal nerves, the pain from the sacroiliac joint itself—previously masked by that nerve pain—often becomes clearly noticeable for the first time. This happens because the pain-signaling nerve pathways from the two areas overlap around the buttock region.

This phenomenon occurs more often in patients who have previously undergone spinal fusion surgery. When a lumbar segment is rigidly fixed, the movement of the upper body and the weight load shift almost entirely onto the sacroiliac joint located just below the fused segment.

In the exam room, the physician asks in detail about true differences in leg bone length, apparent leg-length differences caused by pelvic misalignment, age, pregnancy history, and any history of past trauma or spinal surgery (Cohen SP et al., 2013). This is because when the weight balance across the left and right pelvis is disrupted, it produces abnormal joint movement that can readily trigger sacral pain (Gartenberg A et al., 2021).

When Leg Numbness or Weakness Returns Along with Sacral Pain

With sacroiliac joint pain, patients often report a sharp, stabbing pain on one side of the sacral area when standing up from a chair, standing on one leg, or rolling onto their side in bed. The pain may spread into the buttock or the back of the thigh, but it typically stops above the knee. A tingling, electric-shock-like numbness is usually absent (Cohen SP et al., 2013).

If, along with the sacral pain, leg numbness again shoots below the knee or down to the toes, or if leg weakness appears, nerve root compression should be checked first, ahead of the sacroiliac joint. A nerve function test can assess the degree of compression, and a detailed evaluation to check for nerve root damage may be considered if needed. Bowel or bladder dysfunction, or a sudden drop in strength in both legs, are warning signs that call for immediate emergency evaluation.

Pain severe enough to wake someone at night, or pelvic stiffness lasting more than 30 minutes after waking in the morning, serves as a criterion for distinguishing inflammatory conditions such as ankylosing spondylitis. If a feverish sensation accompanies the pain, infection is promptly evaluated as well. When a cluster of provocation tests—pressing or twisting the pelvis in various directions to check the pain response—is applied, a negative result (no pain response) is a useful clue for looking to other structures for the cause of the sacral pain (McCormick ZL et al., 2025).

Where Are Sacroiliac Joint Injections Given, and What Guides the Needle?

If pain is severe enough that sitting down or standing up is difficult, or a patient cannot get into position for manual therapy, injection treatment to calm inflammation in the joint and ligaments is planned first. Ansim Teunteun Pain Clinic carefully checks the condition of the posterior sacroiliac ligaments and surrounding muscles with ultrasound, then sets a precise treatment target based on the examination findings.

The clinic directly confirms the needle reaching the target point by watching either the fluoroscopic images used for C-arm nerve blocks or real-time ultrasound injection images. The same imaging-guidance equipment is used as for nerve blocks applied to a lumbar disc herniation (the cushion between the vertebrae) or spinal stenosis, but the injection target clearly differs: instead of the spinal nerve pathway, the medication is delivered into the interior of the sacroiliac joint or the posterior ligament complex of the pelvis (Bresnahan JJ et al., 2022).

Sacroiliac joint injections fall into two approaches: injecting into the space inside the joint, and injecting around the posterior ligaments of the joint. The clinic chooses the imaging-guided approach suited to the case — for example, a narrowed joint space from aging or more prominent ligament damage. After a small amount of local anesthetic is injected into the joint, the clinic checks whether the pain drops by 50% or more. This also serves a diagnostic purpose, helping determine whether that joint is the direct source of the pain (McCormick ZL et al., 2025).

When inflammation and swelling are severe, injecting a steroid medication inside and around the joint may lower pain for several weeks (McCormick ZL et al., 2025). The procedure takes about 5 to 10 minutes. Right after the procedure, patients rest briefly while the clinic checks lower-body sensation and pain relief, then they return to daily activities the same day.

How Much Longer Does Pelvic Alignment Need Correcting After the Sacral Pain Settles?

After a sacroiliac joint injection calms the sharp pain, the next step is to evaluate pelvic alignment, leg length discrepancy, and joint range of motion, then continue with manual therapy and spinal adjustment (Gartenberg A et al., 2021). The physician examines the patient's spine and pelvis in the exam room and then takes part in the treatment directly, gently releasing stiff joints and guiding misaligned bones back into proper position.

Manual therapy is usually done 1–2 times per week for about 4–8 weeks, with the number of sessions and intervals adjusted based on how stable the joint is during everyday standing and walking. If a dull, aching pain remains in the ligaments around the pelvis even after the injection, extracorporeal shock wave therapy may be added. This is typically applied 3–5 times at weekly intervals, and studies — including one conducted over 4 weeks with 30 patients — have reported short-term pain relief from shock wave therapy at the sacroiliac joint (PMID 28372309).

To help prevent pelvic misalignment over the long term, a personalized one-on-one rehabilitation program runs alongside these treatments. Pelvic stabilization exercises gradually strengthen the gluteal and abdominal core muscles, building a support base so that body weight doesn't shift onto just one sacroiliac joint while walking (McCormick ZL et al., 2025).

If slight symptoms from a lumbar disc (the cushion between the vertebrae) problem remain, low back pain management is combined with pelvic correction. Once sitting down, standing up, and walking become easier, visit intervals are gradually extended as the patient transitions to self-management.

Jinyeol Kwon · Anesthesiology and Pain Medicine Specialist · Ansim Teunteun Pain Clinic

References

Gartenberg A, Nessim A, Cho W (2021). Sacroiliac joint dysfunction: pathophysiology, diagnosis, and treatment.. Eur Spine J. PMID: 34272605
Cohen SP, Chen Y, Neufeld NJ (2013). Sacroiliac joint pain: a comprehensive review of epidemiology, diagnosis and treatment.. Expert Rev Neurother. PMID: 23253394
McCormick ZL, Hurley RW, Anitescu M (2025). Consensus practice guidelines on sacroiliac joint complex pain from a multispecialty, international working group.. Pain Med. PMID: 41318933
Bresnahan JJ, Ng AT (2022). Review of Sacroiliac Joint Injection Techniques.. Curr Pain Headache Rep. PMID: 35239155
Limited direct evidence for extracorporeal shockwave therapy. PMID: 28372309

Frequently Asked Questions

Q. Should I bring my previous lower back MRI and procedure records?

Bringing your existing MRI images and radiology reports, along with records noting where and when you received any nerve block procedures, can help distinguish the cause of your pain. Ansim Teunteun Pain Clinic compares these previous test and treatment records with the current examination findings to decide how to evaluate your remaining sacral pain.

Q. What information should I share when considering a sacroiliac joint injection after a lumbar nerve block?

Describing, separately, which symptoms improved after the previous injection and which symptoms remain can help. Sharing the date of the injection, the medication used, and any medications you are currently taking also gives your doctor a reference point for deciding the medication and timing of any additional injection.

Q. How should I track pain changes after a sacroiliac joint injection?

Record your pain score before and after the injection, along with any change in movements that used to hurt, such as sitting down and standing up. If you also note when the pain started to ease and how long the relief lasted, Ansim Teunteun Pain Clinic can review that record together with the injection target and examination findings to judge whether that area is involved in the pain.

Q. If pain decreases after an injection but discomfort remains during movement, how is exercise intensity determined?

Exercise range and intensity are set based on how much the pain has decreased, together with any discomfort that remains when standing up or walking. If pain clearly worsens during exercise, the intensity is lowered; if the discomfort continues, the painful area and the joint's range of motion are reassessed to adjust the treatment plan.