Sunday December 9, 2012
A neglected source of pain
By Assoc Prof Dr EUGENE WONG
The sacroiliac joint is often the unsuspected culprit in many instances of lower back pain.
THE sacroiliac (SI) joint as a source of pain was first described in 1905 by Goldwaite and Osgood.
The belief that the SI joint can be a source of low back pain has waxed and waned throughout the 20th century. The lack of awareness of the joint as a pain generator has contributed to diagnostic uncertainty and few available treatment options to address the pain coming from this joint.
Up to 25% of patients presenting to a spine clinic for low back pain have significant contribution from the hip or SI joints. The SI joint is a contributing factor in failed back surgery syndrome in 29-40% of cases.
The SI joints are weight-bearing joints located between the hips and the spine. They are susceptible to wear and tear. There is sliding movement of a few millimetres, tilt and rotation of three degrees.
The function of the SI joints is to allow torsional or twisting movements when we move our legs. Without the SI joints and the pubic symphysis (at the front of the pelvis), which allow these small movements, the pelvis would be at a higher risk of a fracture.
The SI joint may fail because of congenital malformation, increased stresses due to lower back fusion surgery, direct trauma or overuse.
Other causes of SI joint pain include infection, limb length discrepancy, scoliosis, rheumatoid arthritis, gout, psoriasis and osteoarthritis.
Multiple pregnancies may increase the risk of arthritis in the joint later in life.
Sometimes, the cause of the pain is unknown even after extensive investigations.
Findings include pain in the region of the SI joint; stressing the SI joint reproduces the patient’s pain, and injection of local anaesthetic into the joint completely relieves the patient of pain.
The primary reason for SI joint injections is to determine whether or not the joint is the cause of the patient’s pain. It is useful in providing immediate pain relief for some period of time.
First-line treatment often includes pain and anti-inflammatory medication to reduce the swelling that is usually contributing to the patient‘s pain.
An initial short period of rest will help decrease inflammation and relieve the muscle spasm. Some patients benefit from wearing a sacroiliac belt.
Rehabilitation exercises may be performed. These include hamstring stretch, quadriceps stretch, hip adductor stretch, knee to chest stretch, and gluteal sets.
Radiofrequency ablation can be done to ablate pain fibres to the SI joint. This destroys any sensation coming from the joint, and its effect can last for up to two years.
Fusion may be done in cases of severe pain not responding to non-operative management.
Several methods of fusion have been used, including anterior, transgluteal, through the iliac bone, and from posterior approach.
A posterior approach from near the midline has been shown to need a very small incision, but at the same time, offering a better anatomic approach and good visualisation of the SI joint. In this new procedure, an implant is inserted via a small incision (3cm) using special instruments that approximate the ligaments of the pelvic girdle back to their regular state through controlled distraction. This process is called ligamentotaxis.
Bone is then added, which aims to ensure a solid, permanent immobilisation of the joint after the healing phase is complete.
Patients can walk with crutches, and activity is limited to partial weight-bearing on the affected side for the first six weeks. Patients do not suffer stiffness in the traditional sense, or increased stress in the untreated SI joint.
Bilateral fusion is unusual, and seems to occur in cases of increased stress from fused lumbar discs (especially multi-level) or a congenital anomaly.
The results of the surgery are encouraging. Experience to date shows that it provides a reliable method of stabilising the joint and treating the SI pain. Follow-up on more than 200 patients shows significant improvement in quality of life and pain relief, with only a few patients who have not experienced an improvement.
The operation is gentle on the tissue and muscles. The first 70 patients are still reporting significant pain relief after more than four years.
Dr Eugene Wong is adjunct associate professor at Perdana University Graduate School of Medicine. This article is contributed by The Star Health & Ageing Panel, which comprises a group of panellists who are not just opinion leaders in their respective fields of medical expertise, but have wide experience in medical health education for the public. The members of the panel include: Datuk Prof Dr Tan Hui Meng, consultant urologist; Dr Yap Piang Kian, consultant endocrinologist; Datuk Dr Azhari Rosman, consultant cardiologist; A/Prof Dr Philip Poi, consultant geriatrician; Dr Hew Fen Lee, consultant endocrinologist; Prof Dr Low Wah Yun, psychologist; Datuk Dr Nor Ashikin Mokhtar, consultant obstetrician and gynaecologist; Dr Lee Moon Keen, consultant neurologist; Dr Ting Hoon Chin, consultant dermatologist; Prof Khoo Ee Ming, primary care physician; Dr Ng Soo Chin, consultant haematologist. For more information, e-mail firstname.lastname@example.org. The Star Health & Ageing Advisory Panel provides this information for educational and communication purposes only and it should not be construed as personal medical advice.