Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 6: magnetic resonance imaging and discography for patient selection for lumbar fusion

Treatment of Low Back Pain by Treating the Annular High Intensity Zone (HIZ) Lesions Using Percutaneous Transforaminal Endoscopic Disc Surgery

Background

The study design was a retrospective case series. The objective was to find the clinical success rate of percutaneous transforaminal endoscopic disc surgery in patients suffering from discogenic chronic low back pain who were showing high intensity zone (HIZ) with degenerated disc as the only abnormality in the magnetic resonance imaging (MRI). The HIZ in the posterior annulus in degenerated disc is recognized as a pain generator. There are only a few studies available in the literature addressing the effect of identification and treatment of HIZ in the chronic low back pain patient.

Methods

We retrospectively evaluated the case records of all the patients who were treated by percutaneous endoscopic disc surgery for relief of symptoms as determined by visual analog scale (VAS) score, Oswestry Disability Index (ODI), Mac Nab criteria, and the consumption of analgesics, who had the predominant symptom of chronic low back pain, and whose lumbar spine MRI showed degenerated disc with HIZ and no other cause of back pain, like facet joint arthritis or sacroiliac joint arthritis.

Results

A total of 23 patients were identified to include in the study. Mean preoperative duration of low back pain was 13.1 months. Mean follow up after the procedure was 29 months. At final follow up, 69.6% of the patients were not taking any pain medicines, 17.36% were on frequent analgesic medicines, 13.04% were on occasional analgesics. There was statistically significant reduction in VAS at 6 weeks postop and final follow up after surgery and the ODI at final follow up; 82.6% of patients had an excellent/good outcome as per Mac Nab criteria. There were no complications or reoperations in any of the patients.

Conclusions

Visualization and ablation of the chronic annular pathology in HIZ may give an effective and minimally invasive treatment for one of the back pain causes.

Why Lumbar Artificial Disk Replacements (LADRs) Fail

STUDY DESIGN

A retrospective review of prospectively collected data.

OBJECTIVE

To determine why artificial disk replacements (ADRs) fail by examining results of 91 patients in FDA studies performed at a single investigational device exemption (IDE) site with minimum 2-year follow-up.

SUMMARY OF BACKGROUND DATA

Patients following lumbar ADR generally achieve their 24-month follow-up results at 3 months postoperatively.

MATERIALS AND METHODS

Every patient undergoing ADR at 1 IDE site by 2 surgeons was evaluated for clinical success. Failure was defined as <50% improvement in ODI and VAS or any additional surgery at index or adjacent spine motion segment. Three ADRs were evaluated: Maverick, 25 patients; Charité, 31 patients; and Kineflex, 35 patients. All procedures were 1-level operations performed at L4-L5 or L5-S1. Demographics and inclusion/exclusion criteria were similar and will be discussed.

RESULTS

Overall clinical failure occurred in 26% (24 of 91 patients) at 2-year follow-up. Clinical failure occurred in: 28% (Maverick) (7 of 25 patients), 39% (Charité) (12 of 31 patients), and 14% (Kineflex) (5 of 35 patients). Causes of failure included facet pathology, 50% of failure patients (12 of 24). Implant complications occurred in 5% of total patients and 21% of failure patients (5 of 24). Only 5 patients went from a success to failure after 3 months. Only 1 patient went from a failure to success after a facet rhizotomy 1 year after ADR.

CONCLUSIONS

Seventy-four percent of patients after ADR met strict clinical success after 2-year follow-up. The clinical success versus failure rate did not change from their 3-month follow-up in 85 of the 91 patients (93%). Overall clinical success may be improved most by patient selection and implant type.

Correlation between high-intensity zone on MRI and discography in patients with low back pain

The aim of this study was to analyze the correlation between high-intensity zone (HIZ) on magnetic resonance imaging (MRI) of a lumbar disc and positive pain response assessed by discography for the diagnosis and treatment of discogenic low back pain (LBP). Thirty-seven patients aged 21 to 59 years with chronic LBP but without any neurological symptoms or lumbar disc herniation who underwent MRI and subsequent discography were included in this study. During discography, concordant pain was regarded as positive, whereas discordant pain and no pain were regarded as negative. X-ray and computed tomography (CT) after discography with positive pain response were analyzed to correlate with HIZ on MRI. A total of 98 discs underwent discography in 37 patients; 21 discs presented positive pain response, including 10 with HIZ (47.6%). Seventy-seven discs presented negative pain response, including 29 with HIZ (37.6%). The high grade of annular disruption group shows a high proportion of HIZ on MRI. A positive correlation between HIZ and degree of annular disruption was observed. However, no correlation between HIZ and positive pain response was established on discography. The findings confirm that the presence of HIZ on MRI is only a suggestive and screening iconography indication for the diagnosis of discogenic LBP and cannot replace the gold standard of the discography. MRI should be closely integrated with those of discography, and thus, they play a crucial role in selecting operative segments of multilevel lumbar degenerative disk disease.

The lumbar high-intensity zone: 20 years on

The high intensity zone (HIZ) was first described by Aprill and Bogduk on lumbar spine magnetic resonance imaging (MRI) studies in 1992. Correlation with lumbar computed tomography (CT) discography showed that the HIZ represents a deep radial tear of the annulus fibrosus, which may be a cause of chronic low back pain. Initial studies comparing the finding of a HIZ on MRI with discography suggested that it may be a highly specific marker of a painful lumbar disc, but later investigators demonstrated that it is also present in asymptomatic individuals. The purpose of this article is to review the literature regarding the lumbar HIZ 20 years after its initial description.

Surgical management of minimally invasive anterior lumbar interbody fusion with stand-alone interbody cage for L4-5 degenerative disorders: clinical and radiographic findings

Surgical treatment for degenerative spinal disorders is controversial, although lumbar fusion is considered an acceptable option for disabling lower back pain. Patients underwent instrumented minimally invasive anterior lumbar interbody fusion (mini-ALIF) using a retroperitoneal approach except for requiring multilevel fusions, severe spinal canal stenosis, high-grade spondylolisthesis, and a adjacent segments disorders. We retrospectively reviewed the clinical records and radiographs of 142 patients who received mini-ALIF for L4-5 degenerative lumbar disorders between 1998 and 2010. We compared preoperative and postoperative clinical data and radiographic measurements, including the modified Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back and leg pain, disc height (DH), whole lumbar lordosis (WL), and vertebral wedge angle (WA). The mean follow-up period was 76 months. The solid fusion rate was 90.1% (128/142 patients). The average length of hospital stay was 6.9 days (range, 3–21 days). The mean blood loss was 63.7 ml (range, 10–456 ml). The mean operation time was 155.5 min (range, 96–280 min). The postoperative JOA and VAS scores for back and leg pain were improved compared with the preoperative scores. Radiological analysis showed significant postoperative improvements in DH, WL, and WA, and the functional and radiographical outcomes improved significantly after 2 years. The 2.8% complication rate included cases of wound infection, liquorrhea, vertebral body fractures, and a misplaced cage that required revision. Mini-ALIF was found to be associated with improved clinical results and radiographic findings for L4-5 disorders. A retroperitoneal approach might therefore be a valuable treatment option.

Operative and nonoperative treatment approaches for lumbar degenerative disc disease have similar long-term clinical outcomes among patients with positive discography

OBJECTIVE

It remains unclear whether fusion for lumbar degenerative disc disease with positive discography produces better outcomes compared with nonoperative treatment. The aim of this study was to compare outcomes of patients with discography-concordant lumbar degenerative disc disease electing for fusion versus nonoperative treatment.

METHODS

We retrospectively reviewed consecutive patients with back pain and concordant lumbar discogram who were offered fusion. Follow-up questionnaires included pain score, Oswestry disability index, short form-12, and satisfaction scale. Patients were stratified based on whether they elected for fusion or nonoperative treatment.

RESULTS

Overall follow-up was 48% (96/200). Patients lacking follow-up were slightly older (P = 0.021) and less likely to be smokers (P = 0.013). Between patients with and without follow-up, there were no significant differences in pain score at initial visit, body mass index, or gender (P ≥ 0.40). The 96 patients for whom follow-up was obtained included 53 in the operative and 43 in the nonoperative groups. At baseline, there were no significant differences between these groups based on age, pain score, body mass index, smoking, or gender (P ≥ 0.25). Mean follow-up was 63 months for operative and 58 months for nonoperative patients (P = 0.20). The mean pain score at last follow-up improved significantly for operative and nonoperative patients (P < 0.001). At follow-up, operative and nonoperative groups did not differ significantly with regard to pain scores, Oswestry disability index, short form-12, or satisfaction scale.

CONCLUSIONS

Comparison of long-term outcomes for patients with back pain and concordant discography did not demonstrate a significant difference in outcome measures of pain, health status, satisfaction, or disability based on whether the patient elected for fusion or nonoperative treatment.

Comparison of magnetic resonance imaging and computed tomography-myelography for quantitative evaluation of lumbar intracanalar cross-section

PURPOSE

A comparison of MRI and computed tomography-myelography (CTM) for lumbar intracanalar dimensions. To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the lumbar spine.

MATERIALS AND METHODS

MRI and CTM of lumbar disc levels from 61 subjects with various lumbar spinal diseases were studied. Dural area, dural anteroposterior (AP) diameter, dural right-left diameter, and thickness of the ligamentum flavum were measured by two orthopedic surgeons. Each section was graded by degree of stenosis. Absolute value and intra- and inter-observer correlation coefficients (ICC) of these measurements and the associations between MRI and CTM values were determined.

RESULTS

Except for MRI determination of ligament flavum thickness, CTM and MRI and intra- and ICC suggested sufficient reproducibility. When measurements of dural area, dural AP diameter, and RL diameter were compared, values in CTM were significantly (p = 0.01-0.004) larger than those in MRI (CTM/MRI ratios, 119%, 111%, and 105%, respectively). As spinal stenosis became more severe, discrepancies between CTM and MRI in measurements of the dural sac became larger.

CONCLUSION

Both CTM and MRI provided reproducible measurements of lumbar intracanalar dimensions. However, flavum thickness may be more accurately measured by CTM. Because the differences in the measurements between CTM and MRI are very slight and there is very little data to suggest that the precise degree of stenosis is related to symptoms or treatment outcome, the usefulness of the CTM over MRI needs to be confirmed in future studies.

Surgical Management of Neck and Low Back Pain

Surgical intervention for neck pain and low back pain may be of benefit to some patients. It should be considered, however, only in cases where medical management has failed and there is a clearly identifiable anatomic lesion that likely is the pain generator. Indications, preoperative evaluation, and common surgical procedures are reviewed.

Lumbar fusion outcomes in Washington State workers' compensation

STUDY DESIGN

Retrospective population-based cohort study.

OBJECTIVE

To evaluate the influence of lumbar intervertebral fusion devices on clinical and disability outcomes among Washington State compensated workers with chronic back pain.

SUMMARY OF BACKGROUND DATA

The efficacy of lumbar fusion for chronic low back pain remains controversial. Recent randomized controlled trials have shown results of fusion to be equivalent to those of structured exercise and cognitive intervention. Lumbar fusion rates, however, continue to increase nationally, fueled, in part, by introduction of new fusion devices, including intervertebral cages in 1996. It is not known whether these newer devices have improved outcomes, and particularly in compensated workers.

METHODS

In this population-based retrospective cohort study, we identified Washington State injured workers who underwent lumbar fusion between 1994 and 2001 from Washington State Workers' Compensation system administrative database. All the data for this study were obtained from either the claims or medical bill payment databases. Multiple logistic regression analyses were used to examine the association between the surgical technique (interbody cages and/or instrumentation) and the risk of disability, reoperation, and complications following lumbar fusion.

RESULTS

Among the 1,950 eligible subjects, fusions with cages increased from 3.6% in 1996 to 58.1% in 2001. Overall disability rate at 2 years after fusion was 63.9%, reoperation rate 22.1%, and rate for other complications 11.8%. Use of cages or instrumentation was associated with increased complication risk compared with bone-only fusions without improving disability or reoperation rates. Legal, work-related, and psychologic factors predicted worse disability. Discography and multilevel fusions predicted greater reoperation risk. Degenerative disc disease and concurrent decompression procedures predicted lower reoperation risk.

CONCLUSIONS

Use of intervertebral fusion devices rose rapidly after their introduction in 1996. This increased use was associated with an increased complication risk without improving disability or reoperation rates.

Diagnostic relevance of pressure-controlled discography

Discogenic pain is a leading cause of chronic low back pain. The authors investigated the efficacy of pressure-controlled discography to determine its role in clinical decision-making for the management of patients with discogenic pain. Pressure-controlled discography was performed in 21 patients (51 discs) with pain-provocation, followed by post-discography computerized tomography scans. Pain response was classified as positive response and negative response, and measured with visual analog scale scores. Discographic findings were graded by the modified Dallas discogram scale. Elastance, pain provocation on intradiscal pressure, pressure and volume of initial pain response, and pain response intensity were statistically analyzed. Elastance showed significant differences between Grade 0 and Grade 4 and 5. Decreased elastance with positive pain response group was a good indicator to imply that disc degeneration presumably is a pain generator. Results of pain response were well correlated with intradiscal pressure but not with the amount of injected volume. Among 31 discs of Grade 4 and 5, 74% showed negative pain response and 26% showed positive response. It was concluded that pressure-controlled discography was useful to diagnose discogenic pain and excellent guide in decision-making for spinal operations.