GUIDELINES FOR THE PERFORMANCE OF FUSION PROCEDURES FOR DEGENERATIVE DISEASE OF THE LUMBAR SPINE

( IMPORTANT NOTICE The following is a synopsis of the “Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine” as appearing in the Journal of Neurosurgery:Spine , June 2005, Volume 2, Number 6. While every effort was made to capture all the salient information in as a concise and accurate manner possible, it is recommended the original text be obtained and reviewed for in depth assessment of the conclusions arrived at, in this extensively and well researched series of articles, in the J Neurosurger:Spine 2 pages 636 – 740, by logging into the website www.thejns-net.org and obtainng a personal copy.)

1. RADIOGRAPHIC ASSESSMENT OF FUSION.

· Plain X-ray evaluation is accurate in determining fusion status in 2/3 of patients, and therefore is not recommended as a stand alone investigation of fusion status.
· Absence of motion on flexion/extension views is highly suggestive of solid fusion, with 62% correlation to intraoperative findings. The occurrence of some degree of motion does not necessarily indicates a pseudoarthosis.
· Multiplanar CT scan is more sensitive for the detection of pseudoarthosis than Xrays with flexion/extension views
· Technecium 99m Bone scan not sufficiently reliable to diagnosis a pseudoarthosis after spinal fusion.

Option: No gold standard exists to determine non fusion, and it is recommended that a combination of Plain X-ray evaluation, flexion/extension views and Multiplanar CT scan be utilised.

2. CORRELATION BETWEEN RADIOGRAPHIC AND FUNCTIONAL OUTCOME.

Standard: Insufficient evidence to recommend a standard.
Guideline: None
Option: There is a correlation between fusion and clinical outcome. However the correlation between fusion status and clinical outcome is not strong, and in a given patient fusion status may not correlate with clinical outcome.

3. MAGNETIC RESONANCE IMAGING AND DISCOGRAPHY FOR PATIENT SELECTION FOR LUMBAR FUSION.

Standard: Insufficient evidence to recommend a standard.
Guideline:
1. MRI is recommended instead of discography for initial evaluation of chronic low back pain.
2. MRI should be uses to verify anatomically normal disc, not considered for treatment.
3. Discography should not used as stand alone tests for treatment decisions in chronic low back pain.
4. If discography is used diagnostically, it should be at a (MRI) morphologically abnormal disc, and associated with concordant pain responses.
Option:
1. Discography should be used at MRI equivocal levels of pathology, especially adjacent to clearly pathological levels.
2. Recommended that in discographic positive levels, that are normal on MRI, that these should not be considered for operative intervention.
3. Discography not recommended in normal MRI discs.

4. INTRACTABLE LOW-BACK PAIN WITHOUT STENOSIS OR SPONDYLOLISTHESIS

Standard:
Class I evidence would support fusion in the treatment of disabling, intractable low back pain in carefully selected patients, where best medical management has failed.

Guideline: None

Option:
Intensive physical and cognitive therapy is recommended after medical therapy.

5. LUMBAR FUSION FOR DISC HERNIATION AND RADICULOPATHY

Standard: Insufficient evidence to recommend a standard.
Guideline: None
Option:
1. Fusion not recommended in association with discectomy in primary herniated disc presenting with radiculopathy.
2. Fusion is recommended in association with discectomy for primary disc herniation, as a possible adjunct to discectomy if there is instability or deformity, or associated chronic lower back pain
3. Fusion is recommended in association with discectomy for recurrent dic herniation, as a possible adjunct with discectomy, although good results are also obtained with repeat discectomy alone.
4. Fusion is recommended in association with discectomy for recurrrent disc herniation, as a possible adjunct to discectomy if there is instability or deformity, or associated chronic lower back pain.

6. FUSION FOR PATIENTS WITH STENOSIS AND ASSOCIATED SPONDYLOLISTHESIS.

Standard: Insufficient evidence to recommend a standard.
Guideline:
Posterior lumbar fusion (PLF) is recommended in patients requiring decompression for degenerative spinal stenosis with spondylolisthesis.
Option:
Pedicle screw fixation should be considered as an option, in patients requiring decompression for degenerative spinal stenosis with spondylolisthesis, when there is preoperative instability, kyphosis or anticipated iatrogenic instability. Clear definition of instability variably defined in various studies.

7. FUSION FOLLOWING DECOMPRESSION IN PATIENTS WITH STENOSIS WITHOUT SPONDYLOLISTHESIS.

Standard: Insufficient evidence to recommend a standard.

Guideline: Insufficient evidence to recommend a guideline.

Option:
1. Posterior lumbar fusion (PLF) is not recommended if no preoperative instability or deformity is present or iatrogenic instability likely.

8. INTERBODY TECHNIQUES FOR LUMBAR FUSION.

Standard: Insufficient evidence to recommend a standard.

Guideline:

1. Anterior lumbar interbody fusion (ALIF) either stand alone or with posterior instrumentation, the addition of PLF not recommended.
2. Interbody graft is recommended as a treatment option to improve fusion rates and function outcome in patients with degenerative disc disease (DDD), undergoing surgery for lower back pain at one or two levels.
3. Use of multiple approaches, anterior and posterior (360o), to accomplish lumbar fusion is not recommended as a routine for treatment of patients with low back pain without deformity.
4. No recommendation can be made as to the technique to achieve anterior body fusion, as significant differences in clinical outcome between the different techniques have not been convincingly demonstrated.

9. PEDICLE SCREW FIXATION AS AN ADJUNCT TO POSTEROLATERAL FUSION FOR LOW-BACK PAIN

Standard: Insufficient evidence to recommend a standard.

Guideline: Insufficient evidence to recommend a guideline.

Option:

1. Pedicle screw fixation is a treatment option in selected patients with low back pain, with DDD or degenerative spondylolithesis, undergoing PLF, that are considered to be at increased risk of fusion failure, as pedicle screw fixation improves fusion rate, when assessed on plain X-rays with dynamic imaging.
2. Pedicle screw fixation is not recommended routinely as adjunction to PLF in patients with chronic back pain due to DDD, because
Ø Conflicting evidence of Pedicle screw fixation improving functional outcome, although studies showing no benefit have been criticised because of limited sample size.
Ø Consistent evidence that Pedicle screw fixation increases complications and costs associated with procedure

10. INJECTION THERAPIES FOR LOW-BACK PAIN AND AS AN ADJUNCT TO LUMBAR FUSION.

Standard: Facet injections are not recommended as long term treatment of chronic low back pain. There is insufficient evidence to recommend it as a diagnostic test.

Guideline: Insufficient evidence to recommend a therapeutic or diagnostic guideline.

Option:

1. Trigger point, facet joint or epidural injection is recommended as treatment option in selected patients, for temporary or symptomatic relief of chronic back pain in DDD.
2. Facet Joint injection is recommended as diagnostic tool to predict response for lumbar facet joint RF ablation.
3. Facet Joint injection is not recommended as diagnostic tool to predict response to lumbar fusion.

11. BRACING AS AN ADJUNCT TO OR SUBSTITUTE FOR LUMBAR FUSION.

Standard: Insufficient evidence to recommend a standard.

Guideline:
1. Use of rigid lumbar support, for 1- 3 weeks, recommended for lower back pain of short duration ( less than 6 months) (Acute back pain)
2. Not effective in chronic lower back pain populations.

Options:

1. The prophylactic use of back brace in workers with previous history of back injury appears to decrease the number of days sick leave due to back pain.
2. The prophylactic use of back brace in general working population does not decrease back pain or related time off work.
3. No evidence to suggest that pre operative pain relief with brace indicates favourable outcome following lumbar fusion.
4. No information is available on benefit of bracing on fusion rate or clinical outcome following instrumented fusion for degenerative lumbar disease.
5. If brace used, rigid brace seems to offer benefit over soft brace.

12. ELECTROPHYSIOLOGICAL MONITORING AND LUMBAR FUSION.

Standard: Insufficient evidence to recommend a standard.

Guideline:

1. No evidence in literature to support any form of routine intra operative monitoring in improving outcome in decompression or fusions for degenerative spinal disease.
2. The use of Somatosensory Evoked Potential (SSEP) or Dermatomal sensory evoked potential (DSEP) is recommended in instrumented lumbar procedures where the surgeon requires immediate intra operative information with respect to neurological injury.
3. Post operative neurological deficit is highly correlated with intra operative monitoring changes.
4. An abnormal SSEP or DSEP during surgery does not correlate well with post operative neurological injury as there is a high false positive rate.
5. Use of evoked intra operative EMG is recommended where lack of neurological injury is to be confirmed during pedicle screw placement. A normal evoke EMG response is highly predictive of lack of neurological injury, and intact pedicle wall.
6. Intra operative monitoring does not provide useful information with respect to adequacy of nerve root decompression.

13. BONE GRAFT EXTENDERS AND SUBSTITUTES

Standard:
The use of autologous bone or rhBMP (recombinant human bone morphogenetic protein) is recommended in ALIF with threaded titanium cage.

Guideline: Insufficient evidence to recommend a standard.

Options:

1. rhBMP-2 in combination with HA (Hydroxyapatite) and tricalcium phosphate may be used as a substitute for autologous bone in some case of PLF.
2. Several formulations of calcium phosphate exist and are recommended as bone graft extenders in certain circumstances, especially when used with autologous bone.

14. BONE GROWTH STIMULATORS AND LUMBAR FUSION.

Standard: Insufficient evidence to recommend a standard.

Guideline:

1. There are a number of studies that support ES (electrical stimulation) for the promotion of bone healing following lumbar fusion.
2. These are expensive.
3. Class II and III evidence suggests use of DCS (Direct current stimulation) or CCS (Capacitative coupled stimulation) in patients with high risk of fusion failure in PLF. No benefit in fusion rates in non high risk fusion failure patients demonstrated.
4. Class II and III evidence suggests use of PEMFS (Pulsed electromagnetic field stimulation) for promoting fusion in interbody fusion.
5. Although fusion rates improved in specific patients,, there is no consistent medical evidence to support or refute the use of the Electrical stimulation devices to improve patient outcomes.