Lumbar Degenerative Disc Disease
Lumbar Degenerative Disc Disease, also known as Lumbar Spondylosis, means changes in the intervertebral disc due to ageing and wear and tear. This is a physiologic process of normal ageing of the disc. In this ageing process, the disc loses its hydration or the water content and desiccates over a period of years and decades. This desiccation leads to small tears in the disc with subsequent deformation presenting as collapse, bulging, herniation or extrusion of disc material.
This leads to loss of cushioning effect of the discs. Process of disc degeneration may lead to secondary changes like facet arthritis, hypertrophy and synovial fluid collection leading to synovial cyst formation, Interbody osteophytes, thickening with or without calcification of ligamentum flavum (a ligament along the back of the spinal sac) etc.
This process of ageing can be accelerated due to contributory factors like supraphysiologic activity like that seen in athletes, microtrauma like in people doing repetitive movement, injuries to the back, smoking, diabetes, and other systemic illnesses, congenital or acquired deformity of the spine. The degenerative process is asymptomatic in vast majority of the patients.
Presentation of Lumbar Degenerative Disc Disease
The patients with lumbar degenerative disease or lumbar spondylosis can present with back pain or leg pain or a combination of both. The back pain can be due to degenerative pathology itself. The leg pain may present in the form of radiculopathy in a specific nerve root area also called the dermatome or may present with neurologic claudication as a presentation of lumbar canal stenosis.
Both of these phenomena are due to nerve root compression caused either by the degenerative disc, degenerative facet or osteophytes. The patient’s may also present with loss of normal lumbar lordosis due to collapse of the intervertebral space. These patients may have degenerative scoliosis or curvature of the lower back along with loss of height of the patient. Rarely these patients may have neurologic deficits which may be as subtle as a weakness of great toe to as severe as weakness of the foot and ankle muscles or involvement of bowel or bladder. The patients usually complaint of tingling and numbness also.
The patient with lumbar canal stenosis present with neurological claudication in which the patient is not able to walk long distances. Such patients also inform that their pain or heaviness in the legs is improved by stooping forwards. They also inform of grocery cart sign in which they tend to lean on the grocery cart while they are shopping. These patients should be differentiated from vascular claudication which is essentially due to blockage of the blood vessels to the leg.
Natural History Of Lumbar Degenerative Disc Disease
Natural history of the lumbar degenerative disease is that of waxing and waning (episodic). The disease is usually stable with episodic exacerbations over a period of years. Only a small subset of patients deteriorate significantly and rarely do patients develop significant neurological deficit. The patients with radicular pain, tingling and numbness usually improve over time. The patients with subtle weakness like that of the muscle of great toe may also improve or stay at the same level for many months to years. Occasionally, patients may develop major neurological deficits or may have no improvement in their symptoms without medical intervention. Patients who fail all conservative measures may need surgical treatment. Rarely, the patients may develop cauda equina syndrome which may need urgent medical attention.
Warning signs or the red flags of Lumbar Degenerative Disc Disease
The patients who complain of back pain or leg pain should seek urgent medical attention in the presence of the following signs or symptoms –
- Cancer, neoplasia or malignancy.
- Unexplained weight loss of more than 10 pounds in the last 6 months.
- Immunocompromised comorbidities like on chemo or radiotherapy or having disease like HIV or AIDs or being on prolonged corticosteroid therapy.
- IV drug users.
- Urinary tract infection.
- Fever of more than 100 degrees centigrade.
- Significant trauma from a fall or accident.
- Bowel or bladder involvement in the form of incontinence or retention.
- Weakness in the major joint of leg
Patients with degenerative lumbar disc disease usually need:
- X rays – standing as well as dynamic films – to look for fractures, alignment of the spine, curvature, instability
- Magnetic Resonance Imaging – to know more about the type and location of compression and the lesion
Occasionally patients may need:
- Computed Tomography
- Bladder studies
Lumbar Degenerative Disc Disease Treatment Options
Most of patients with degenerative lumbar disease are treated conservatively. Treatment involves physical therapy to strengthen the core muscles of the lumbar spine, medications which help in decreasing the pain in the back as well as in the leg. The patient may occasionally need a nerve block to get rid of their radicular symptoms. The patients who do not get better with conservative means, may require surgical treatment. Patients who present with worsening of neurological deficit or acute presentation of neurological deficit may require urgent surgery to halt the progression and possible reversal of the neurological deficits.
Indications for Surgery in Lumbar Degenerative Disc Disease
The patients with lumbar degenerative disease who are not improved with conservative means and present with significant restriction of activity, quality of life and work due to radicular symptoms or lumbar canal stenosis have a good chance to improve with surgical management of the disease process.
The patients who only have back pain and no radicular symptoms are not the best candidates for these surgeries, though if carefully selected many of these patients can have good relief from their symptoms by spine surgeries. Good trial for conservative means for at least three months for patients who only have back pain should be done before discussing regarding the options for surgery. The patients who have radicular symptoms need decompression surgeries if they have back pain also or their imaging studies show instability of the lumbar spine, then they may also need fusion surgeries.
Decompression surgery involve removal of the back of the vertebrae and include surgeries like laminectomy and discectomy. Minimal invasive procedures like microdiscectomy, endoscopic discectomy, foraminotomy, endoscopic laminectomy can also have in carefully selected patients. Fusion surgery includes posterior spinal fusion or interbody fusion which can be of multiple types including transforaminal, lateral, oblique or anterior lumbar interbody fusion. The type of fusion is decided by taking the consideration of pathology, location of the pathology as well as patient’s characteristics.
Surgical Treatment of Lumbar Degenerative Disc Disease
Appropriate surgical treatment for patients with degenerative lumbar disc disease who fail conservative management or present with acute or rapidly worsening neurological deficits may need to undergo on of the following surgeries:
- Discectomy – can be done in multiple ways, most common being Microdiscectomy (with the use of microscope) or Endoscopic Discectomy (using a endoscope through a tube. This involves removing the disc fragment which is causing the compression of the nerve root after making a window through the bone to reach the disc from the back.
- Decompression Laminotomy or Laminectomy – can be of many types including foraminotomy, laminotomy, laminectomy. This involved removing the compression over the nerve roots from the back by removing the bone and the ligament causing the compression.
- Spine Fusion surgery – is needed in presence of instability, significant back pain or need for procedure which may lead to instability. It can be of many types and the decision for one over the other depends on type and location of pathology and instability among other factors.
The bone graft is inserted with the help of the instruments shown above during a spinal fusion surgery.
The shavers are used in spinal fusion surgery to remove the intervertebral disc material and create space for insertion of a bone cage along with bone graft to aid in the fusion of the involved segments.
Prognosis After Lumbar Spine Surgery
The patients who have radicular symptoms or neurological claudication usually have good to excellent results after decompression surgeries. These patients if also have significant back pain or instability respond well to fusion surgeries. The patient’s who have only back pain and have failed all conservative means may have fair to good result after back fusion surgeries.
Certain risk factors for poor results after spine surgery are:
- Obstructive sleep apnea
- High blood pressure
- Other medical conditions involving your heart, lungs or kidneys
- Medications, such as aspirin, that can increase bleeding
- History of heavy alcohol use
- Drug allergies
- History of adverse reactions to anesthesia
Which Patients Are Good Candidates For Lumbar Degenerative Disc Disease Surgery?
- The patients who have radiculopathy in the form of pain, tingling or numbness in a particular dermatome or one or both lower extremity
- Patients who have neurological claudication in the form of pain or heaviness of the leg with or without tingling or numbness going down both lower extremities after standing or walking for certain distance
What are the risk of Lumbar Degenerative Disc Disease Surgery?
- Hematoma or hemorrhage
- Damage to the major vessels which may result in excessive bleeding, even death
- Damage to the dura, resulting in a cerebrospinal fluid leak
- Failure, loosening or pull out of the cage, graft, rod or screws
- Wound infection
- Failure of fusion to happen
- Damage to the nerve root(s) resulting in new onset or deterioration of preexisting pain, weakness, paralysis, loss of sensation, loss of bowel or bladder function, impaired sexual function, etc., which may or may not recover.
- A few of these conditions may warrant repeat surgery