Correction to: Disc inflammation and Modic changes show an interaction effect on recovery after surgery for lumbar disc herniation.

In Tables 3 and 4: In the first column and row, the text reads "Mixed model test (patients with Modic changes)". This should have been just "Mixed model". The complete correct Tables 3 and 4 are given below.

Disc inflammation and Modic changes show an interaction effect on recovery after surgery for lumbar disc herniation.

PURPOSE: To study the interaction between Modic changes (MC) and inflammation by macrophages in the disc, in relation to clinical symptoms before and after discectomy for lumbar disc herniation. METHODS: Disc tissue was embedded in paraffin and stained with haematoxylin and CD68. Subsequently, tissue samples were categorized for degree of inflammation. Type of MC was scored on MRI at baseline. Roland Disability Questionnaire (RDQ) score and visual analogue scale for back pain and leg pain separately were considered at baseline and 1-year follow-up post-surgery. Main and interaction effects of MC and inflammation were tested against clinical outcome questionnaires. In addition, this analysis was repeated in bulging and extruded discs separately. RESULTS: Disc material and MRI's of 119 patients were retrieved and analysed. Forty-eight patients demonstrated mild inflammation, 45 showed moderate inflammation, and 26 showed considerable inflammation. In total, 49 out of 119 patients demonstrated MC. Grade of disc inflammation did not associate with the presence of MC. At baseline, no main or interaction effects of MC and inflammation were found on the clinical scores. However, during follow-up after discectomy, significant interaction effects were found for RDQ score: Only in patients with MC at baseline, patients remained significantly more disabled (3.2 points p = 0.006) if they showed considerable disc inflammation compared to patients with mild inflammation. The additional analysis showed similar results in extruded discs, but no significant effects in bulging discs. CONCLUSIONS: An interaction effect of MC and disc inflammation by macrophages is present. Only in patients with MC, those with considerable inflammation recover less satisfactory during follow-up after surgery. These slides can be retrieved under Electronic Supplementary Material.

Gadolinium Enhancement Is Not Associated With Disc Inflammation in Patients With Sciatica.

STUDY DESIGN: Retrospective observational histological study. OBJECTIVE: To evaluate the reliability of gadolinium enhancement as a marker for inflammation by associating gadolinium enhancement findings with the degree of inflammation as measured by macrophage infiltration in disc material retrieved during disc surgery in patients with sciatica. SUMMARY OF BACKGROUND DATA: Disc inflammation often occurs in sciatica patients, a noninvasive tool that is used to assess disc inflammation is Gadolinium enhanced MR imaging. METHODS: Disc tissue was retrieved from patients in the Sciatica trial (N = 119), a multicenter randomized controlled trial in patients with sciatica. Disc tissue was embedded in paraffin and stained with hematoxylin and CD68. Tissue samples were categorized as mild (0-10 macrophages/cm), moderate (10-100 macrophages/cm), and considerable (>100 macrophages/cm) inflammation. Of the 119 MRIs, 96 were additionally performed with contrast-enhanced gadolinium. RESULTS: Seventy-four patients showed gadolinium enhancement of the disc herniation and 26 of the nerve root. Degree of inflammation by macrophages was not associated with gadolinium enhancement of nerve roots or herniated discs. These results did not change if the patient groups with and without Modic type 2 changes were evaluated separately. Furthermore, no associations were observed between gadolinium enhancement and presence of Modic type 2 changes. CONCLUSION: This study found gadolinium enhanced MRI findings to be unreliable as an indicator for inflammation of disc herniation or nerve root in patients with sciatica. LEVEL OF EVIDENCE: 2.

Preoperative MRI in Patients With Intermittent Neurogenic Claudication: Relevance for Diagnosis and Prognosis.

STUDY DESIGN: We studied baseline magnetic resonance images of 155 patients with intermittent neurogenic claudication and lumbar spinal stenosis (LSS). Magnetic resonance imaging (MRI) and patient data were gathered from participants of a randomized trial. OBJECTIVE: It is believed that the narrowness of the lumbar spinal canal correlates to the severity of complaints and that it may be a good predictor of clinical outcome if treated. However, this hypothesis has never been (prospectively) tested. SUMMARY OF BACKGROUND DATA: MRI is an important tool to confirm the diagnosis of LSS as a cause for intermittent neurogenic claudication. METHODS: Three raters were asked to evaluate the magnetic resonance images (Schizas scale). Symptom severities at baseline and 1-year follow-up were quantified. The radiological scores were correlated with clinical baseline and outcome scores to assess diagnostic and prognostic value of MRI findings at baseline. RESULTS: There was good agreement on the clinically relevant level of LSS (kappa range 0.57-0.64). MRI assessment of grading of compression (kappa 0.33-0.46) did not correlate with baseline MRDQ nor with outcome based on postoperative change in MRDQ (P = 0.61). However, both absence of epidural fat and presence of tortuous caudal nerves on magnetic resonance images (kappa 0.53-0.72 and 0.67-0.70) in patients with LSS were relatively good predictors for satisfactory recovery after surgery (P = 0.03 and P < 0.01). CONCLUSION: The grading of compression on the preoperative MRI is neither ambiguous nor correlating to severity of clinical condition. It does, furthermore, not have the ability to predict the outcome after 1 year if surgically treated. LEVEL OF EVIDENCE: 2.

Thoracic epidural haematoma due to a subclavian steal syndrome and secondary formed thoracic collateral circuits, coincidence or consequence: a case report.

Despite profound diagnostics, the aetiology of spinal epidural haematoma (SEH) often remains unknown. In this case, diagnostics revealed an SEH at the fifth and sixth thoracic levels due to a subclavian steal syndrome with a tortuous vascular loop between the sixth thoracic intercostal artery and the costocervical arteries deriving from the left subclavian artery with plump arteries in the epidural space. The patient underwent decompression surgery and a percutaneous transluminal angioplasty. The patient showed good recovery at follow-up. The SEH was a result of secondary formed thoracic collateral circuits with epidural involvement due to a subclavian steal syndrome.

Prognostic value of magnetic resonance imaging findings in patients with sciatica.

OBJECTIVE This study aimed to determine the prognostic value of MRI variables to predict outcome in patients with herniated disc-related sciatica, and whether MRI could facilitate the decision making between early surgery and prolonged conservative care in these patients. METHODS A prospective observational evaluation of patients enrolled in a randomized trial with 1-year follow-up was completed. A total of 283 patients with sciatica who had a radiologically confirmed disc herniation were randomized either to surgery or to prolonged conservative care with surgery if needed. Outcome measures were recovery and leg pain severity. Recovery was registered on a 7-point Likert scale. Complete/near complete recovery was considered a satisfactory outcome. Leg pain severity was measured on a 0- to 100-mm visual analog scale. Multiple MRI characteristics of the degenerated disc herniation were independently scored by 3 spine experts. Cox models were used to study the influence of MRI variables on rate of recovery, and linear mixed models were used to determine the predictive value of MRI variables for leg pain severity during follow-up. The interaction of each MRI predictor with treatment allocation was tested. There were no study-specific conflicts of interest. RESULTS Baseline MRI variables associated with less leg pain severity were the reader's assessment of presence of nerve root compression (p < 0.001), and assessment of extrusion compared with protrusion of the disc herniation (p = 0.006). Both variables tended to be associated, but not significantly, with satisfactory outcome during follow-up (HR 1.45, 95% CI 0.93-2.24, and HR 1.24, 95% CI 0.96-1.61, respectively). The size of disc herniation at baseline was not associated with outcome. There was no significant change in the effects between treatment groups. CONCLUSIONS MRI assessment of the presence of nerve root compression and extrusion of a herniated disc at baseline was associated with less leg pain during 1-year follow-up, irrespective of a surgical or conservative treatment. MRI findings seem not to be helpful in determining which patients might fare better with early surgery compared with a strategy of prolonged conservative care. Clinical trial registration no.: ISRCTN26872154 ( controlled-trials.com ).

Influence of low back pain and prognostic value of MRI in sciatica patients in relation to back pain.

BACKGROUND: Patients with sciatica frequently complain about associated back pain. It is not known whether there are prognostic relevant differences in Magnetic Resonance Imaging (MRI) findings between sciatica patients with and without disabling back pain. METHODS: The study population contained patients with sciatica who underwent a baseline MRI to assess eligibility for a randomized trial designed to compare the efficacy of early surgery with prolonged conservative care for sciatica. Two neuroradiologists and one neurosurgeon independently evaluated all MR images. The MRI readers were blinded to symptom status. The MRI findings were compared between sciatica patients with and without disabling back pain. The presence of disabling back pain at baseline was correlated with perceived recovery at one year. RESULTS: Of 379 included sciatica patients, 158 (42%) had disabling back pain. Of the patients with both sciatica and disabling back pain 68% did reveal a herniated disc with nerve root compression on MRI, compared to 88% of patients with predominantly sciatica (P<0.001). The existence of disabling back pain in sciatica at baseline was negatively associated with perceived recovery at one year (Odds ratio [OR] 0.32, 95% Confidence Interval 0.18-0.56, P<0.001). Sciatica patients with disabling back pain in absence of nerve root compression on MRI at baseline reported less perceived recovery at one year compared to those with predominantly sciatica and nerve root compression on MRI (50% vs 91%, P<0.001). CONCLUSION: Sciatica patients with disabling low back pain reported an unfavorable outcome at one-year follow-up compared to those with predominantly sciatica. If additionally a clear herniated disc with nerve root compression on MRI was absent, the results were even worse.

Reliability of gadolinium-enhanced magnetic resonance imaging findings and their correlation with clinical outcome in patients with sciatica.

BACKGROUND CONTEXT: Gadolinium-enhanced magnetic resonance imaging (Gd-MRI) is often performed in the evaluation of patients with persistent sciatica after lumbar disc surgery. However, correlation between enhancement and clinical findings is debated, and limited data are available regarding the reliability of enhancement findings. PURPOSE: To evaluate the reliability of Gd-MRI findings and their correlation with clinical findings in patients with sciatica. STUDY DESIGN: Prospective observational evaluation of patients who were enrolled in a randomized trial with 1-year follow-up. PATIENTS SAMPLE: Patients with 6- to 12-week sciatica, who participated in a multicentre randomized clinical trial comparing an early surgery strategy with prolonged conservative care with surgery if needed. In total 204 patients underwent Gd-MRI at baseline and after 1 year. OUTCOME MEASURES: Patients were assessed by means of the Roland Disability Questionnaire (RDQ) for sciatica, visual analog scale (VAS) for leg pain, and patient-reported perceived recovery at 1 year. Kappa coefficients were used to assess interobserver reliability. METHODS: In total, 204 patients underwent Gd-MRI at baseline and after 1 year. Magnetic resonance imaging findings were correlated to the outcome measures using the Mann-Whitney U test for continuous data and Fisher exact tests for categorical data. RESULTS: Poor-to-moderate agreement was observed regarding Gd enhancement of the herniated disc and compressed nerve root (kappa<0.41), which was in contrast with excellent interobserver agreement of the disc level of the herniated disc and compressed nerve root (kappa>0.95). Of the 59 patients with an enhancing herniated disc at 1 year, 86% reported recovery compared with 100% of the 12 patients with nonenhancing herniated discs (p=.34). Of the 12 patients with enhancement of the most affected nerve root at 1 year, 83% reported recovery compared with 85% of the 192 patients with no enhancement (p=.69). Patients with and without enhancing herniated discs or nerve roots at 1 year reported comparable outcomes on RDQ and VAS-leg pain. CONCLUSIONS: Reliability of Gd-MRI findings was poor-to-moderate and no correlation was observed between enhancement and clinical findings at 1-year follow-up.

Back pain's association with vertebral end-plate signal changes in sciatica.

BACKGROUND CONTEXT: Patients with sciatica frequently experience disabling back pain. One of the proposed causes for back pain is vertebral end-plate signal changes (VESC) as visualized by magnetic resonance imaging (MRI). PURPOSE: To report on VESC findings, changes of VESC findings over time, and the correlation between VESC and disabling back pain in patients with sciatica. STUDY DESIGN/SETTING: A randomized clinical trial with 1 year of follow-up. PATIENTS SAMPLE: Patients with 6 to 12 weeks of sciatica who participated in a multicenter, randomized clinical trial comparing an early surgery strategy with prolonged conservative care with surgery if needed. OUTCOME MEASURES: Patients were assessed by means of the 100-mm visual analog scale (VAS) for back pain (with 0 representing no pain and 100 the worst pain ever experienced) at baseline and 1 year. Disabling back pain was defined as a VAS score of at least 40 mm. METHODS: Patients underwent MRI both at baseline and after 1 year follow-up. Presence and change of VESC was correlated with disabling back pain using chi-square tests and logistic regression analysis. RESULTS: At baseline, 39% of patients had disabling back pain. Of the patients with VESC at baseline, 40% had disabling back pain compared with 38% of the patients with no VESC (p=.67). The prevalence of type 1 VESC increased from 1% at baseline to 35% 1 year later in the surgical group compared with an increase from 3% to 11% in the conservative group. The prevalence of type 2 VESC decreased from 40% to 29% in the surgical group while remaining almost stable in the conservative group at 41%. The prevalence of disabling back pain at 1 year was 12% in patients with no VESC at 1 year, 16% in patients with type 1 VESC, 11% in patients with type 2 VESC, and 3% in patients with both types 1 and 2 VESC (p=.36). Undergoing surgery was associated with increase in the extent of VESC (odds ratio [OR], 8.6; 95% confidence interval [CI], 4.7-15.7; p<.001). Patients who showed an increase in the extent of VESC after 1 year did not significantly report more disabling back pain compared with patients who did not show any increase (OR, 1.2; 95% CI, 0.6-2.6; p=.61). CONCLUSION: In this study, undergoing surgery for sciatica was highly associated with the development of VESC after 1 year. However, in contrast with the intuitive feeling of spine specialists, those with and those without VESC reported disabling back pain in nearly the same proportion. Therefore, VESC does not seem to be responsible for disabling back pain in patients with sciatica.

Predictive value of MRI in decision making for disc surgery for sciatica.

OBJECT: In a randomized controlled trial comparing surgery and prolonged conservative treatment for sciatica of 6-12 weeks' duration, more than one-third of patients assigned to conservative treatment underwent surgery. The objective of the present study was to evaluate whether MRI at baseline could have predicted this delayed surgery. METHODS: Independently evaluated qualitative and quantitative MRI findings were compared between those patients who did and those who did not undergo surgery during follow-up in the conservative care group. In addition, area under the receiver operating characteristic (ROC) curve analysis was used to assess how well MRI parameters discriminated between those who did and those who did not undergo delayed surgery (0.5-0.7 poor discrimination, ≥ 0.7 acceptable discrimination). RESULTS: Of 142 patients assigned to receive prolonged conservative care, 55 patients (39%) received delayed surgery. Of the 55 surgically treated patients, 71% had definite nerve root compression at baseline compared with 72% of conservatively treated patients (p = 0.76). Large disc herniations (size > 50% of spinal canal) were nearly equally distributed between those who did and those who did not undergo surgery (25% vs 21%, p = 0.65). The size of the dural sac was smaller in the patients who underwent surgery (101.2 vs 122.9 mm(2), p = 0.01). However, the size of the dural sac discriminated poorly between those who did and those who did not undergo delayed surgery (area under ROC curve, 0.62). CONCLUSIONS: In patients who suffered from sciatica of 6-12 weeks' duration, MRI at baseline did not distinguish between patients who did and those who did not undergo delayed surgery.

Magnetic resonance imaging interpretation in patients with sciatica who are potential candidates for lumbar disc surgery.

BACKGROUND: Magnetic Resonance Imaging (MRI) is considered the mainstay imaging investigation in patients suspected of lumbar disc herniations. Both imaging and clinical findings determine the final decision of surgery. The objective of this study was to assess MRI observer variation in patients with sciatica who are potential candidates for lumbar disc surgery. METHODS: Patients for this study were potential candidates (n = 395) for lumbar disc surgery who underwent MRI to assess eligibility for a randomized trial. Two neuroradiologists and one neurosurgeon independently evaluated all MRIs. A four point scale was used for both probability of disc herniation and root compression, ranging from definitely present to definitely absent. Multiple characteristics of the degenerated disc herniation were scored. For inter-agreement analysis absolute agreements and kappa coefficients were used. Kappa coefficients were categorized as poor (<0.00), slight (0.00-0.20), fair (0.21-0.40), moderate (0.41-0.60), substantial (0.61-0.80) and excellent (0.81-1.00) agreement. RESULTS: Excellent agreement was found on the affected disc level (kappa range 0.81-0.86) and the nerve root that most likely caused the sciatic symptoms (kappa range 0.86-0.89). Interobserver agreement was moderate to substantial for the probability of disc herniation (kappa range 0.57-0.77) and the probability of nerve root compression (kappa range 0.42-0.69). Absolute pairwise agreement among the readers ranged from 90-94% regarding the question whether the probability of disc herniation on MRI was above or below 50%. Generally, moderate agreement was observed regarding the characteristics of the symptomatic disc level and of the herniated disc. CONCLUSION: The observer variation of MRI interpretation in potential candidates for lumbar disc surgery is satisfactory regarding characteristics most important in decision for surgery. However, there is considerable variation between observers in specific characteristics of the symptomatic disc level and herniated disc.

Magnetic resonance imaging in follow-up assessment of sciatica.

BACKGROUND: Magnetic resonance imaging (MRI) is frequently performed during follow-up in patients with known lumbar-disk herniation and persistent symptoms of sciatica. The association between findings on MRI and clinical outcome is controversial. METHODS: We studied 283 patients in a randomized trial comparing surgery and prolonged conservative care for sciatica and lumbar-disk herniation. Patients underwent MRI at baseline and after 1 year. We used a 4-point scale to assess disk herniation on MRI, ranging from 1 for "definitely present" to 4 for "definitely absent." A favorable clinical outcome was defined as complete or nearly complete disappearance of symptoms at 1 year. We compared proportions of patients with a favorable outcome among those with a definite absence of disk herniation and those with a definite, probable, or possible presence of disk herniation at 1 year. The area under the receiver-operating-characteristic (ROC) curve was used to assess the prognostic accuracy of the 4-point scores regarding a favorable or unfavorable outcome, with 1 indicating perfect discriminatory value and 0.5 or less indicating no discriminatory value. RESULTS: At 1 year, 84% of the patients reported having a favorable outcome. Disk herniation was visible in 35% with a favorable outcome and in 33% with an unfavorable outcome (P=0.70). A favorable outcome was reported in 85% of patients with disk herniation and 83% without disk herniation (P=0.70). MRI assessment of disk herniation did not distinguish between patients with a favorable outcome and those with an unfavorable outcome (area under ROC curve, 0.48). CONCLUSIONS: MRI performed at 1-year follow-up in patients who had been treated for sciatica and lumbar-disk herniation did not distinguish between those with a favorable outcome and those with an unfavorable outcome. (Funded by the Netherlands Organization for Health Research and Development and the Hoelen Foundation; Controlled Clinical Trials number, ISRCTN26872154.).

Root compression on MRI compared with clinical findings in patients with recent onset cervical radiculopathy.

OBJECTIVES: To evaluate the occurrence of symptomatic and asymptomatic root compression caused by herniated discs and spondylotic foraminal stenosis by MRI in patients with recent onset cervical radiculopathy. PARTICIPANTS: 78 patients with symptoms and signs of cervical radiculopathy of less than one month's duration. METHODS: The authors determined the clinically suspected level of root compression in each patient. Two neuroradiologists independently evaluated MRIs, blinded for the clinical findings. For each patient, the level of root compression on MRI was compared with the clinically affected level. The authors also examined the cause of compression: herniated disc, spondylotic foraminal stenosis or both. RESULTS: In 73% of patients, the clinically affected root was compressed on MRI. In 45%, MRI showed root compression without clinical substrate together with, or to a lesser extent without, the coexistence of compression of the clinically affected root. MRIs were assessed as normal in 13-15% of cases, and in 9-10% only asymptomatic roots were compressed. Herniated discs without spondylosis were more often responsible for root compressions only at the clinically affected level and spondylotic foraminal stenosis for multiple root compression including compression of clinically unaffected roots. CONCLUSION: MRI findings in patients with cervical radiculopathy should be interpreted together with the clinical findings, as false-positive and false-negative MRIs occur rather frequently.

Simultaneous measurements of cerebral oxygenation changes during brain activation by near-infrared spectroscopy and functional magnetic resonance imaging in healthy young and elderly subjects.

Near infrared spectroscopy (NIRS) and functional magnetic resonance imaging (fMRI) both allow non-invasive monitoring of cerebral cortical oxygenation responses to various stimuli. To compare these methods in elderly subjects and to determine the effect of age on cortical oxygenation responses, we determined motor-task-related changes in deoxyhemoglobin concentration ([HHb]) over the left motor cortex in six healthy young subjects (age 35 +/- 9 years, mean +/- SD) and five healthy elderly subjects (age 73 +/- 3 years) by NIRS and blood-oxygen-level-dependent (BOLD) fMRI simultaneously. The motor-task consisted of seven cycles of 20-sec periods of contralateral finger-tapping at a rate as fast as possible alternated with 40-sec periods of rest. Time-locked averages over the seven cycles were used for further analysis. Task-related decreases in [HHb] over the motor cortex were measured by NIRS, with maximum changes of -0.83 +/- 0.38 mumol/L (P < 0.01) for the young and -0.32 +/- 0.17 mumol/L (P < 0.05) for the elderly subjects. The BOLD-fMRI signal increased over the cortex volume under investigation with NIRS, with maximum changes of 2.11 +/- 0.72% (P < 0.01) for the young and 1.75 +/- 0.71% (P < 0.01) for the elderly subjects. NIRS and BOLD-fMRI measurements showed good correlation in the young (r = -0.70, r(2) = 0.48, P < 0.001) and elderly subjects (r = -0.82, r(2) = 0.67, P < 0.001). Additionally, NIRS measurements demonstrated age-dependent decreases in task-related cerebral oxygenation responses (P < 0.05), whereas fMRI measurements demonstrated smaller areas of cortical activation in the elderly subjects (P < 0.05). These findings demonstrate that NIRS and fMRI similarly assess cortical oxygenation changes in young subjects and also in elderly subjects. In addition, cortical oxygenation responses to brain activation alter with aging.