by Mikiela Montgomery
I. Description
The purpose of lumbar fusion surgery is to relieve pain, numbness, tingling and weakness that is associated with a problematic vertebral segment.1 By stopping the motion at a particular vertebral segment, the symptoms resulting from the vertebral segment should significantly decrease. There are several options for lumbar spinal fusion surgeries, all of which include adding a bone graft to the area in order to stop the painful motion. After the bone graft is in place, a natural biological response occurs which allows the graft to grow within the vertebral segments, which in turn creates a fusion.2
II. Anatomy:
The spinal column is comprised of 24 vertebrae that surround and protect the spinal cord. The 24 vertebrae are classified as 3 separate areas that consist of 7 cervical, 12 thoracic, and 5 lumbar vertebrae. There is also a sacrum and coccyx that provides stability for the pelvis. Between each vertebrae, there are intervertebral discs that are present to serve as shock absorbers and allow for mobility of the spine in all directions. 1
III. Indications
Lumbar spinal fusion surgery may be indicated for several different types of symptoms. Most often, lumbar spine issues are first treated conservatively prior to discussions of surgery. If certain symptoms don't improve with conservative treatment such as low back pain, numbness, tingling, or weakness in the legs, lumbar spinal fusion may be indicated. The most common complaint of patients who receive the fusion is sciatica (leg pain). 1
IV. Incidence/ Prevalence:
Lumbar fusions are becoming increasingly more prevalent in the United States. Lumar spinal fusions are seen most frequently among patients aged 60 and above. In 2001, there were over 122,000 lumbar fusions performed nationwide for degenerative conditions. This represented a 220% increase from 1990, where the number of fusions were 100,000. After the approval of the use of lumbar fusion cages in 1996, fusions increased 113%. The rate of lumbar fusions are higher than hip replacements and knee arthroplasty.3
V. Clinical Presentation
Lumbar spinal fusion can cause certain limitations to a patient post-operatively. Patients may be seen with a back brace, which is used to help immobilize the trunk in order for the graft to remain intact. Physicians may not prescribe a brace for all patients, but for some, it may be suggested. Patients will often have substantial stiffness in their trunk, therefore, decreasing the amount of range of motion that is available to them. This may limit the activities of daily living and cause the patient to alter their functional activities. Twisting, bending, and jumping should be avoided immediately following surgery to prevent disrupting the bone graft. There may also be point tenderness on the back, over the incision sites. Scar tissue formation may continue to build around the incision sites which also has the potential of causing limitations in ranges of motion.
VI. Potential Etiologies:
Several pathologies may lead to one needing a lumbar spinal fusion surgery.
Spondylolysthesis
Spondylolysthesis is a condition in which one vertebra slips forward, on top of the one below it. This has the potential to cause a lot of pain if the vertebra continues to move back and forth because the nerve can become affected. If the nerve becomes irritated, it may cause symptoms of pain, numbness/tingling, and/or weakness in the leg. If conservative treatment does not alleviate these symptoms, a lumbar spinal fusion may be indicated to stop the abnormal motion. 1,2
Degenerative Disc Disease
Degenerative Disc Disease occurs when the intervertebral discs shrink and cause abnormal motion in the spine. Abnormal or improper movement over time and/or a traumatic accident can cause a degenerative disc and pain.4The abnormal motion that may occur may cause the vertebrae to compress the spinal nerves, which can lead to tingling, numbness, and/or pain the legs. 2
Spinal Stenosis
Spinal Stenosis is a narrowing of the spinal canal. This narrowing may be caused by arthritis of the vertebrae, bony spurs, or a herniated disk
VII. Diagnostic Tests:
Discography
Prior to undergoing a lumbar spinal fusion surgery, some surgeons often suggest that some patients undergo a discography procedure in order to locate the patient's pain. Discography is most commonly used as a planning tool prior to a lumbar spinal fusion. Spinal surgeons consider a lumbar discography for patients who despite undergoing conservative treatment for low back pain, continue having debilitating pain in the low back, hip, groin, and/or leg.
A discogram is used in order for spinal surgeons to understand lthe physiology of the intervertebral disc. Determining the pain generating disc is important because if a fusion is performed on a level that is painless, the procedure will be ineffective. A lumbar X-ray or CT scan can determine a disc that is abnormal in look, but a severely derformed disc could be less painful than a minimally deformed disc. The discogram will allow the spinal surgeons to pin-point where the fusion should take place.
If lumbar spinal fusion is performed on an area that was free of pain, spine surgery will not help. The patient may have to undergo rehabilitation for a fused spine and still be symptomatic if the wrong levels were fused. Lumbar spinal fusion is a serious procedure, so knowing as much information about the structures prior to the surgery, the better the chances of success.5
VIII. Evaluation/Special Orthopedic Tests:
Following a lumbar fusion, there are certain tests and movements that will be performed to document the patient's progress.
- Active Movements
- flexion, extension, side bending. Overpressure should not be applied immediately following surgery, being mindful not to stress the bone graft.
- Quick Tests
- Prior to surgery, quick tests may be performed such as a squat or hop. Following surgery, these movements should be limited.
- Clearing Joints Above and Below
- Hip, Sacroilliac Joint, Knee, and Ankle should all be cleared prior to surgery.
- Special Tests
- Straight Leg Raise test may indicate a damaged disc or nerve root compression. If there is numbness and tingling in the lower legs following surgery, manual traction may alleviate those symptoms.
- Neurological Exam
- Dermatomes, Myotomes, Reflexes
- Palpation
- Palpation of the vertebrae
IX. Conservative Treatment:
Conservative treatment options for lumbar back pain may include:
- Medications
- Physical Therapy
- TENS Unit/Muscle Stimulators
- Steroid Injections/Nerve Blocks
- Education
- Implementation of Proper Body Mechanics
- Pain Management
- Traction
- Aquatic Therapy
- Acupuncture
- Back Brace
Most physicians will instruct a patient to particpate in conservative management of their low back pain in an attempt to prevent a surgical procedure. 2
X. Surgery & post-op treatment:
Prior to the surgical procedure, your surgeon will take X-rays of the spine, in order to ensure the correct location is targeted. An incision will be made depending on the specific fusion that is performed, and the skin will then be separated. Another X-ray will be performed following the incision to check the correct level of the lumbar vertebrae. The surgeon will then remove any pressure from the nerves by removing portions of the lamina. The disc fragments and any bone spurs will then be taken off, which removes any additional pressure or tension form the nerves.
In preparation of the fusion, the surgeon will then shave off a layer of bone from the specific vertebral level. The bone graft will most likely be taken form the hip, specifically the top of the pelvis. This piece of bone is then placed on the vertebral level where the initial bone was removed. The bone is layed in strips, and once the bone contacts the area, the fusion will begin. The fusion is the body healing itself just as a bone fracture would heal.
To facilitate the healing of the fusion, the surgeon will place metal screws, plates, and/or rods to fix the bones in place. The hardware will be in place to prevent the vertebrae from moving because the least amount of motion gives the higher chance for fusion success.6
There are several different fusion types that your surgeon may choose for you:
- Posterolateral gutter fusion
- The spinal procedure is performed from the back of the spine
- Posterior Lumbar Interbody Fusion
- The spinal procedure is performed from the back. The intervertebral disc is removed and replaced with a bone graft between the vertebral segments.
- Anterior Lumbar Interbody Fusion
- The spinal procedure is performed from the front. The intervertebral disc is removed and replaced with a bone graft between the vertebral segments.
- Anterior/Posterior Spinal Fusion
- The spinal procedure is performed from the front and the back. 1,2
Post-Operative Treatment
Post-operative treatment is essential to having a postive recovery after undergoing a lumbar spinal fusion. Following surgery, the fusion takes about three months to achieve its initial degree of maturation. Initially, the bone graft can be easily damaged, therefore, surgeons usually restrict certain activities for the first three months following surgery. Activities such as twisting, bending the lower back, lifting, and running can severely damage the newly formed graft, so they should be avoided.
Many surgeons may suggest a brace to be used after surgery that can range from a soft corset brace, to one that is a rigid and plastic.
Any time the body undergoes a surgical procedure, the muscles will become significantly deconditioned. Rehabilitation for lumbar spinal fusion focuses on stretching, strengthening, and aerobic conditioning. 7
Meeting with a physical therapist following the fusion surgery is essential and will allow for a more positive prognosis.
Following surgery, smaller muscles, which are needed in maintaining stability of the spine, often become inhibited. Re-educating these muscles to fire will allow the patient to actively stabilize and reduce the stress through the surgical area.
Initially, short walks and stretching will be the best activity for a patient following surgery. It is important to begin walking in order to begin causing the trunk to stabilize itself and initiate muscular activity. Hamstring, quadriceps, and mid back stretching is essential due to the proximity of the nerve roots. Stretching may prevent adhesions or scars from forming around the nerve. Caution should be taken when stretching a nerve and patient's should consult with a physician prior to starting a stretching program. Discomfort may be felt during the stretches, but pain should be avoided.7
XI. Modalities
The following modalities should be used following surgery:
- Ice packs - Ice should be used in the first 2-3 days following surgery. Ice will decrease swelling in the area which will inturn, reduce pain. Ice should be used frequently.
- Heat packs - Heat should be used later on in recovery to reduce pain and create relaxation. Heat will add blood flow to the area and may increase swelling, so ice should be used directly following surgery.
- TENS - Studies have shown that individuals using TENS have required less pain medication following spinal fusion than those who did not use a TENS unit. 7
For patients with any type of spinal fusion, ultrasound is contraindicated and could be detrimental to the patient. In a spinal fusion, there is metal inserted into the skin, which could heat up with ultrasound. Ultrasound waves reach deep into the tissues as opposed to a heat pack (which is more superficial), therefore, it could heat up the hardware that is holding the fusion together. This can cause serious problems for the patient instead of adding any type of pain relief.
XII. Additional Web Based Resources:
www.spine-health.com
www.orthoinfo.aaos.org
www.neurosurgical.com
www.eorthopod.com
