Lumbar Spine Treatment | Disc Replacement Surgeon Singapore

Lumbar spinal stenosis (narrowing of the space for the nerve in the lower back) is a condition affecting mainly the middle aged and beyond.

It happens because of gradual narrowing of the space for the nerves. One of the functions of the spinal column in our body is to facilitate passage and exit of various nerves. The nerves in the lower back or lumbar spine mainly travel to the legs, and they serve both motor (giving instructions to the muscles in the legs to move) and sensory (receiving various sensory feedback from the skin of the legs) functions. Some of the nerves that travel in the lower back spinal column are responsible for control of the bladder and bowel.

Contributing Factors

Ligamentum flavum or yellow ligament in the spinal canal which thickens over time.

Enlarged facet joints on both sides of the spinal column that protrude against the nerves

Bulging discs that protrude against the nerves

Mis-alignment of the spinal column resulting in compression of the nerves. If there is forward slip of the vertebra when viewed from the side, this is called spondylolisthesis (Figure 1). Similarly, if there is a backward slip of the vertebra when viewed from the side, this is called retrolisthesis. If there is mis-alignment when viewed from the back, this is called scoliosis (Figure 2).

An x-ray of a forward slip of the vertebra viewed from the side

Figure 1

An x-ray of a spinal misalignment viewed from the back

Figure 2

Common Symptoms

Pain in the legs or calves, as well as the lower back after standing and walking, which is relieved by sitting down or leaning over. When the low back is bent forward, slightly more space is made available for the nerves, causing a reduction in symptoms.

Numbness, pins and needles sensation, or loss of motor strength of the leg(s). These complaints invariably lead to significant impairment in the quality of the life. One will find shopping, traveling, and meeting up with friends a great chore as the leg symptoms keep “acting up” whenever one stands or walks beyond a period of time. In one third of cases, the ability to walk will gradually diminish.

Diagnosis

Medical history. It is important during the clinical consultation to rule out peripheral vascular disease (lack of blood flow to the legs) as another possible diagnosis.

Physical examination

Investigations

X-rays – reveal structural changes, such as loss of disc height, bone spurs, and mal-alignment (signify abnormal motion and perhaps instability) of the spine.

MRI (Figure 3) – a closer assessment of any evidence of compression of the nerves, and if there are, what are the offending structures (e.g. discs, bone spurs, thickened ligaments).

An MRI scan on the low back (lumbar) spinal nerve

Figure 3

Treatment

Non-Surgical

In the absence of severe or progressive nerve damage, the doctor will usually manage spinal stenosis using the following non-surgical measures:

Non-steroidal anti-inflammatory drugs to reduce inflammation and relieve pain. Other medications that modulate the nerve pain can also be used, for example pregabalin.

Prescribed exercises and/or physiotherapy to maintain motion of the spine, strengthen abdominal and back muscles, and build endurance, all of which help stabilize the spine. The patient may be encouraged to try slowly progressive aerobic activity such as swimming or using exercise bicycles.

A lumbar corset or back brace to provide some support and help regain mobility. This approach is sometimes used if the patient has weak abdominal muscles or multi-level degeneration of the spine. The corset should be used on a temporary basis only, as prolonged use may weaken the back and abdominal muscles.

Acupuncture to help with pain management.

Spinal Injection

The doctor may recommend spinal injections if the above non surgical treatments do not adequately relieve the symptoms. Spinal injections or nerve root blocks near the affected nerve(s) are done to temporarily relieve pain and nerve inflammation. This can be done as a day surgery procedure in the operating room where sterility is ensured and imaging access to the spine is available. At the same time, injections into the facet joints and the medial branch nerves (nerve supply to the facet joints) may also be done to relieve inflammation of the facet joints.

Surgery

Surgery should be considered immediately if one develops numbness or weakness that interferes with walking, impaired bowel or bladder function. Otherwise, surgery may be considered if there are no significant improvements with non surgical treatments, or the quality of life is significantly affected.

The purpose of the surgery is to relieve pressure on the nerves (decompression), as well as restore and maintain alignment of the spine at times (stabilization). Such procedures can be done via minimally invasive techniques using specially designed tubular systems.

Decompression

Decompression can be done by decompressive laminectomy, i.e. removal of the lamina (roof) of one or more vertebrae to create more space for the nerves. This procedure can often be done via a minimally invasive manner using various tubular retractors. The decompression will remove any structures that compress the nerve(s), including the enlarged ligamentum flavum / yellow ligament, bone spurs from the facet joints, and protruding discs.

Stabilization

If the affected spinal segment is also unstable e.g. spondylolisthesis (forward slip of the vertebra) or lateral listhesis in degenerative scoliosis (sideway slip of the vertebra), stabilization may be needed. This entails both fusion and instrumentation. Fusion often involves the use of the patient’s own bone from the removed lamina or facet. Instrumentation involves placement of titanium screws into the vertebrae (Figure 4).

Various methods may be used to enhance fusion and strengthen the unstable segments of the spine, e.g. the use of cages placed in the intervertebral disc spaces (Figure 4). The doctor may also use BMP (bone morphogenetic protein) to improve the fusion success rate, especially in patients with higher risks of the vertebrae not uniting e.g. in diabetics, smokers, multi-level surgeries, and revision surgeries.

An x-ray of five titanium screws placed on the vertebrae

Figure 4

Non fusion surgery

Non-fusion surgery (often done in a minimally invasive manner) can be used in the surgical treatment of lumbar spinal stenosis in some patients. Non-fusion surgery is possible with the use of dynamic devices (e.g. interspinous spacers inserted between the spinous processes of the back) in conjunction with decompression laminectomy, in order to restrict but not completely eliminate spinal motion at the affected level.

Lumbar Spinal Stenosis