Clinical symptoms of lumbar spinal stenosis associated with morphological parameters on magnetic resonance images

Spinal morphological change after posterior lumbar interbody fusion in lumbar spondylolisthesis patients

Lumbar spondylolisthesis is a degenerative status in the spine. Posterior lumbar interbody fusion (PLIF) with instrumentation has considered as the standard surgical treatment for lumbar instability. Spinal canal and dural sac cross-sectional area (CSA) has been major parameters for evaluating neurologic symptoms. This study is aimed at finding the radiological change using the dural sac CSA and spinal canal CSA as an objective morphological parameter after PLIF. Of the 74 patients (24 men, 50 women; mean age 66.49 years) who had PLIF surgery were checked for preoperative magnetic resonance imaging (MRI) and MRI within 1 week after surgery. T2-weighted axial MRI scans were obtained from each patient. We measured the dural sac and spinal canal CSA on an axial MRI image at the center of L4 to L5 intervertebral disc. The average spinal canal CSA was 70.28 ± 27.77 mm2 in the preoperative MR images and 149.59 ± 35.20 mm2 in the postoperative MR images. The average dural sac CSA was 42.46 ± 18.49 mm2 in the preoperative MR images and 98.93 ± 29.32 mm2 in the postoperative MR images. After the PLIF operation, the mean spinal canal CSA was 112.84 percent increase, and the measn dural sac CSA was 132.99 percent increase. After PLIF, patients had significantly higher dural sac CSA (P < .001) and spinal canal CSA (P < .001). Spinal canal CSA have increased by 112.84 percent and Dural sac CSA have increased by 132.99 percent after PLIF. Thus, before PLIF, the treating physician should carefully explain this result to patient.

Automatic segmentation of dura for quantitative analysis of lumbar stenosis: A deep learning study with 518 CT myelograms

BACKGROUND

The diagnosis of lumbar spinal stenosis (LSS) can be challenging because radicular pain is not often present in the culprit-level localization. Accurate segmentation and quantitative analysis of the lumbar dura on radiographic images are key to the accurate differential diagnosis of LSS. The aim of this study is to develop an automatic dura-contouring tool for radiographic quantification on computed tomography myelogram (CTM) for patients with LSS.

METHODS

A total of 518 CTM cases with or without lumbar stenosis were included in this study. A deep learning (DL) segmentation algorithm 3-dimensional (3D) U-Net was deployed. A total of 210 labeled cases were used to develop the dura-contouring tool, with the ratio of the training, independent testing, and external validation datasets being 150:30:30. The Dice score (DCS) was the primary measure to evaluate the segmentation performance of the 3D U-Net, which was subsequently developed as the dura-contouring tool to segment another unlabeled 308 CTM cases with LSS. Automatic masks of 446 slices on the stenotic levels were then meticulously reviewed and revised by human experts, and the cross-sectional area (CSA) of the dura was compared.

RESULTS

The mean DCS of the 3D U-Net were 0.905 ± 0.080, 0.933 ± 0.018, and 0.928 ± 0.034 in the five-fold cross-validation, the independent testing, and the external validation datasets, respectively. The segmentation performance of the dura-contouring tool was also comparable to that of the second observer (the human expert). With the dura-contouring tool, only 59.0% (263/446) of the automatic masks of the stenotic slices needed to be revised. In the revised cases, there were no significant differences in the dura CSA between automatic masks and corresponding revised masks (p = 0.652). Additionally, a strong correlation of dura CSA was found between the automatic masks and corresponding revised masks (r = 0.805).

CONCLUSIONS

A dura-contouring tool was developed that could automatically segment the dural sac on CTM, and it demonstrated high accuracy and generalization ability. Additionally, the dura-contouring tool has the potential to be applied in patients with LSS because it facilitates the quantification of the dural CSA on stenotic slices.

Prevalence of and factors associated with stenotic thoracic ligamentum flavum hypertrophy

INTRODUCTION

Stenotic thoracic ligamentum flavum hypertrophy can cause leg and/or low back pain similar to that caused by lumbar spinal stenosis. However, the thoracic spine may occasionally be overlooked in patients with leg and/or low back pain. An accurate understanding of the prevalence of stenotic thoracic ligamentum flavum hypertrophy and its associated factors is necessary.

METHODS

In this prevalence study, we reviewed whole-spine MRI scans of patients who visited the pain clinic complaining of leg and/or low back pain between 2010 and 2019. We analyzed the overall prevalence and prevalence according to the age group, sex, grade of lumbar disc degeneration, and thoracic level. In addition, we identified factors independently associated with stenotic thoracic ligamentum flavum hypertrophy occurrence.

RESULTS

Among 1896 patients, the overall prevalence of stenotic thoracic ligamentum flavum hypertrophy was 9.8% (185/1896), with the highest prevalence observed in the ≥80-year-old age group among all age groups (15.9%, 14/88). The region with the highest prevalence was the T10/11 level (3.0%, 57/1896). Multivariable logistic regression analysis revealed that when compared with the <50-year-old age group, all other age groups were significantly associated with stenotic thoracic ligamentum flavum hypertrophy (p<0.01). In addition, grade 5 of lumbar disc degeneration was significantly associated with stenotic thoracic ligamentum flavum hypertrophy (p=0.03).

CONCLUSIONS

Given the possibility for missed stenotic thoracic ligamentum flavum hypertrophy to potentially result in neurological complications, extending lumbar spine MRI covering the lower thoracic region may be considered for patients over 50 years of age with suspected severe lumbar disc degeneration.

Surgical versus nonsurgical management of lumbar degenerative spondylolisthesis based on spinal canal cross-sectional area

Disability and pain associated with lumbar degenerative spondylolisthesis (LDS) result in a significant burden on both the healthcare costs and patients' quality of life. Currently, there exists controversy regarding employment of either nonsurgical management (NSM) or surgical management (SM) in a clinical setting. Spinal canal cross-sectional area (SCA) has been an important morphological parameter for the analysis of LDS. However, there is lack of research about the comparative value of NSM and SM according to SCA. Moreover, previous research have not yet evaluated the clinical most suitable cutoff values of SCA. The objective of this research was to evaluate the effective of NSM and SM for LDS using SCA as an objective morphological parameter. The axial T2 magnetic resonance imaging images were obtained from each patient. We collected SCA samples from 149 patients with LDS. 72 patients underwent SM and the rest did NSM. We measured SCA at the L4/5 LDS on magnetic resonance imaging using a picture archiving and communications system. We measured SCA at the intervertebral disk posterior border, turning down to reach the facet joint side on the opposite edge at the L4/5 level. The average SCA value was 114.34 ± 48.11 mm2 in the NSM group and 69.88 ± 27.87 mm2 in the SM group. Therefore, the SM group had considerably lower SCA (P < .001). In view of the effectiveness of SCA as a prediction factor of surgical option, Receiver Operating Characteristic curve analysis show the optimal cutoff value for SCA as 83.21 mm2, with 70.8% sensitivity, 71.4% specificity, and an area under the curve of 0.80 (95% CI, 0.73-0.87). The narrower the SCA, the higher the probability of SM. Thus, it is proposed that to evaluate surgical decision making, the pain physician should carefully inspect the SCA.

Influence of radiological factors, psychosocial factors, and central sensitization-related symptoms on clinical symptoms in patients with lumbar spinal canal stenosis

BACKGROUND

No study to date has concurrently evaluated the impact of radiological factors, psychosocial factors, and central sensitization (CS) related symptoms in a single lumbar spinal canal stenosis (LSS) patient cohort.

OBJECTIVE

To investigate the associations between these factors and clinical symptoms in LSS patients.

METHODS

We recruited 154 patients with LSS scheduled for surgery. Patient-reported outcome measures and imaging evaluation including clinical symptoms, psychosocial factors, CS-related symptoms, and radiological classifications. Spearman's rank correlation coefficient and multiple regression analyses were employed.

RESULTS

Spearman's correlation revealed CS-related symptoms positively correlated with low back pain (r= 0.25, p< 0.01), leg pain (r= 0.26, p< 0.01), and disability (r= 0.32, p< 0.01). Pain catastrophizing positively correlated with leg pain (r= 0.23, p< 0.01) and disability (r= 0.36, p< 0.01). Regression analysis showed that pain catastrophizing was associated with disability (β= 0.24, 95%CI = 0.03-0.18), and CS-related symptoms with low back pain (β= 0.28, 95%CI = 0.01-0.09). Radiological classifications were not associated with clinical symptoms.

CONCLUSION

Our findings suggest that psychosocial factors and CS-related symptoms, rather than radiological factors, seem to contribute to clinical symptoms in patients with LSS.

The impact of Diabetes in patients with lumbar stenosis - A propensity-score matched study on patient-reported outcomes after surgery

STUDY DESIGN

Registry-based cohort study.

OBJECTIVE

To evaluate the impact of Diabetes (DM) on Patient-reported Outcomes (PROs) after surgery for lumbar spinal stenosis (LSS).

METHOD

Patients from the Danish national spine registry, DaneSpine, scheduled for LSS surgery were identified. MRI of patients with and without DM was graded in regards to lumbar stenosis, disc degeneration (DD), muscular fat infiltration, and Modic changes. In addition, preoperative and two-year postoperative data were collected including PROs. Patients with DM were propensity-score matched (PSM) to non-DM patients.

RESULTS

In total, 296 patients were included, 41 DM and 255 non-DM. Of these, 27 patients from each group were successfully matched. The PSM DM group had less improvement and worse leg pain at two-year follow-up compared to the non-DM group, VAS 58 vs. 36 (p = 0.004). Physical disability was significantly worse at two-year follow-up in the DM group compared to the non-DM group, Oswestry Disability Index score of 38 vs. 29 (p = 0.05). On the preoperative MRI, the number of patients with severe grade LSS and severe fat infiltration in Multifidus muscles was significantly higher in the PSM DM group compared to the non-DM group, (p < 0.01).

CONCLUSION

Patients with concomitant LSS and DM have a significantly reduced improvement in leg pain, more physical disability, and worse leg pain scores at two-year follow-up post-surgery compared to patients without DM. In elderly patients with LSS, there should be an increased focus on DM and the clinically relevant threshold for spine surgery.

Early-stage chronic venous disorder as a cause of leg pain overlooked for lumbar spinal disease

Leg pain can be caused by both lumbar spinal disease and chronic venous disorder (CVD) of leg veins, but their clinical differences have not been thoroughly investigated. This study aimed to determine the incidence of CVD among patients visiting a spine center for leg pain. A total of 196 cases underwent ultrasound examination with a diagnosis rate were 85.7% (168 cases). CVD-diagnosed cases were divided into two groups based on the severity of lumbar spinal disease. The Clinical grades, symptom areas, and symptom types were compared. The differences in symptom improvements with vasoactive medication were also assessed. The most common symptom area was calf then the foot in CVD, while calf then thigh in lumbar spinal disease. Tingling-paresthesia was the most common symptom type for both, with pain and cramping similarly common in CVD and pain more common than cramping in lumbar spinal disease. Considering that the majority of CVD cases (78.6%) had minor cutaneous changes and almost half of cases (41.7%) had refluxes only in tributaries, significant differences in symptom improvement in CVD-dominant group suggested that early-stage venous reflux is a symptomatic disease and a possible cause of leg pain and other symptoms.

The Implication of Preoperative Central Stenosis on Patient-Reported Outcomes After Lumbar Decompression Surgery

OBJECTIVE

To assess the impact of central stenosis severity on patient-reported outcomes after lumbar decompression.

METHODS

Patient diagnosis, demographics, and surgical characteristics were collected via query search and manual chart review of electronic medical records. The inclusion criteria were posterior lumbar decompressions from 2014-2020, with accessible magnetic resonance imaging reports. As previously validated by Lee et al., central stenosis was determined on magnetic resonance imaging and graded as none, mild, moderate, or severe. Patients were dichotomized into 2 groups to improve statistical power for comparisons: none or mild central stenosis and moderate or severe central stenosis. Patient-reported outcome measures (PROMs) were compared between cohorts at 1 year postoperatively. Statistical significance was set at P < 0.05.

RESULTS

On bivariate analysis, no significant differences were noted between cohorts with regard to preoperative, 1-year postoperative, and delta PROMs. In addition, no significant difference in the number of patients attaining minimal clinically important difference (MCID) for each PROM was noted between cohorts. With the exception of mental score of the Short Form-12 survey, all intragroup preoperative to postoperative PROMs indicated significant improvement (all P < 0.05) after lumbar decompression surgery. Multivariate regression identified moderate or severe central canal stenosis as a significant independent predictor of improvement in visual analog scale back (estimate = -1.464, P = 0.045).

CONCLUSIONS

We demonstrate that patients with moderate or severe central spinal stenosis may have more improvement in back pain than those with mild or no central stenosis after lumbar spine decompression surgery.

Characteristics of the Patients with Poor Clinical Outcomes After Symptomatic Postoperative Lumbar Epidural Hematoma

OBJECTIVE

Symptomatic postoperative lumbar epidural hematoma (PLEH) may lead to poor outcomes even after evacuation. This study aimed to verify the short-term clinical outcomes after the evacuation of PLEH and to clarify the characteristics of the patients with poor postoperative outcomes.

METHODS

Twenty-five patients (average age; 70.4 years) underwent PLEH evacuation after lumbar spine surgery. The mean follow-up period was 12.0 (range 3-37) months. Pre and postoperative Japanese Orthopedic Association scores and visual analog scale (VAS) of low back pain (LBP), leg pain, and leg numbness were retrospectively collected. The dural sac cross-sectional area at the most compressed level was measured on magnetic resonance imaging. The patients were classified into 2 groups: poor outcome group (P group) had less than 50% of Japanese Orthopedic Associationrecovery rate and good group (G group) with 50% or more recovery rate.

RESULTS

The rate of delayed evacuation (over 24 hours of onset) was significantly higher in P group than in G group (P = 0.027). There was no significant difference in dural sac cross-sectional areabetween the 2 groups (P = 0.438). VAS of LBP, leg pain, and leg numbness in G group significantly improved postoperatively. Although VAS of LBP and leg pain in P group significantly improved postoperatively, there was no significant difference between the pre and postoperative VAS of leg numbness.

CONCLUSIONS

Delayed evacuation of PLEH can lead to poor postoperative outcomes after lumbar spine surgery. Moreover, patients with poor outcomes remained with postoperative leg numbness. Early evacuation of symptomatic PLEH is key to avoid poor outcomes and persistent leg numbness.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of lumbar spinal stenosis, 2021 - Secondary publication

BACKGROUND

The Japanese Orthopaedic Association (JOA) guideline for the management of lumbar spinal stenosis (LSS) was first published in 2011. Since then, the medical care system for LSS has changed and many new articles regarding the epidemiology and diagnostics of LSS, conservative treatments such as new pharmacotherapy and physical therapy, and surgical treatments including minimally invasive surgery have been published. In addition, various issues need to be examined, such as verification of patient-reported outcome measures, and the economic effect of revised medical management of patients with lumbar spinal disorders. Accordingly, in 2019 the JOA clinical guidelines committee decided to update the guideline and consequently established a formulation committee. The purpose of this study was to describe the formulation we implemented for the revision of the guideline, incorporating the recent advances of evidence-based medicine.

METHODS

The JOA LSS guideline formulation committee revised the previous guideline based on the method for preparing clinical guidelines in Japan proposed by the Medical Information Network Distribution Service in 2017. Background and clinical questions were determined followed by a literature search related to each question. Appropriate articles based on keywords were selected from all the searched literature. Using prepared structured abstracts, systematic reviews and meta-analyses were performed. The strength of evidence and recommendations for each clinical question was decided by the committee members.

RESULTS

Eight background and 15 clinical questions were determined. Answers and explanations were described for the background questions. For each clinical question, the strength of evidence and the recommendation were both decided, and an explanation was provided.

CONCLUSIONS

The 2021 clinical practice guideline for the management of LSS was completed according to the latest evidence-based medicine. We expect that this guideline will be useful for all medical providers as an index in daily medical care, as well as for patients with LSS.

The association between clinical symptoms of lumbar spinal stenosis and MRI axial imaging findings

Purpose:

In diagnosing lumbar spinal stenosis (LSS), Magnetic Resonance Imaging (MRI) is appropriate to confirm the presence of anatomical stenosis of the spinal canal or compression of the nerve roots. However, it is known that morphological LSS is often present in asymptomatic subjects. There is still controversy about the relationship between anatomical LSS and symptomatic LSS. The aim of this study was to assess the association between qualitative imaging findings on MRI of the lumbar spine and symptomatic LSS.

Patients and methods:

This was a cross-sectional study of 239 volunteers from an epidemiological survey that included 1,862 participants in total. MRI of the lumbar spine was evaluated in four categories: morphological grading of central stenosis and lateral recess stenosis, presence of the sedimentation sign, and severity of facet joint effusion. The relationship between these morphological evaluations and typical LSS symptoms as assessed by the self-administered, self-reported history questionnaire for lumbar spinal stenosis (LSS-SSHQ) was investigated by multiple logistic regression analysis.

Results:

The odds ratio of the most severe central stenosis to no stenosis was 15.5 (95%CI: 1.4-164.9). Only the most severe central stenosis was associated with typical LSS symptoms, but not all cases with typical LSS symptoms were due to severe central stenosis.

Conclusion:

Extreme severe central stenosis was strongly related to typical LSS symptoms. However, although subjects with severe central stenosis showed symptoms suggestive of LSS, these subjects did not always show typical LSS symptoms.

The Role of Vertebral Morphometry in the Pathogenesis of Degenerative Lumbar Spinal Stenosis

The aim of the current study was to establish whether the vertebral morphometry (e.g., vertebral body width and spinal canal diameters) is associated with degenerative lumbar spinal stenosis (DLSS). A retrospective computerized tomography (CT) study from L1 to L5 for two sample populations was used. The first included 165 participants with symptomatic DLSS (sex ratio 80 M/85F), and the second had 180 individuals from the general population (sex ratio: 90 M/90F). Vertebral body length (VL) and width (VW) were significantly greater in the stenosis males and females compared to their counterparts in the control. The mean VL in the stenosis males was 31.3 mm at L1, 32.6 mm at L2, 34 mm at L3, 34.1 mm at L4, and 34.5 at L5 compared to 29.9 mm, 31.3 mm, 32.6 mm, 32.8 mm, and 32.9, respectively, in the control group (P ≤ 0.003). Additionally, the bony anterior-posterior (AP) canal diameters and cross-sectional area (CSA) were significantly smaller in the stenosis group compared to the control. The mean AP canal values in the stenosis males were 17.8 mm at L1, 16.6 mm at L2, 15.4 mm at L3, 15.6 mm at L4, and 16.1 at L5 compared to 18.7, 17.8, 16.9, 17.6, and 18.8, respectively, in the control group. Vertebral length (OR-1.273 to 1.473; P ≤ 0.002), AP canal diameter (OR-0.474 to 0.664; P ≤ 0.007), and laminar inclination (OR-0.901 to 0.856; P ≤ 0.025) were significantly associated with DLSS. Our study revealed that vertebral morphometry has a role in DLSS development.

The Association of MRI Findings and Long-Term Disability in Patients With Chronic Low Back Pain

STUDY DESIGN

Longitudinal cohort study with 13-year follow-up.

OBJECTIVE

To assess whether long-term disability is associated with baseline degenerative magnetic resonance imaging (MRI) findings in patients with low back pain (LBP).

METHODS

In 2004-2005, patients aged 18 to 60 years with chronic LBP were enrolled in a randomized controlled trial and lumbar MRI was performed. Patients completed the Roland-Morris Disability Questionnaire (RMDQ) and the LBP Rating Scale, at baseline and 13 years after the MRI. Multivariate regression analysis was performed with 13-year RMDQ as the dependent variable and baseline disc degeneration (DD, Pfirrmann grade), Modic changes (MC), facet joint degeneration (FJD, Fujiwara grade) smoking status, body mass index, and self-reported weekly physical activity at leisure as independent variables.

RESULTS

Of 204 patients with baseline MRI, 170 (83%) were available for follow-up. Of these, 88 had Pfirrmann grade >III (52%), 67 had MC (39%) and 139 had Fujiwara grade >2 (82%) on at least 1 lumbar level. Only MC (β = -0.15, P = .031) and weekly physical activity at leisure (β = -0.51, P < .001) were significantly, negatively, associated with 13-year RMDQ-score (R² = 0.31).

CONCLUSION

DD and FJD were not associated with long-term disability. Baseline MC and weekly physical activity at leisure were statistically significantly associated with less long-term disability.

Prevalence and Predictive Factors of Asymptomatic Spondylotic Cervical Spinal Stenosis in Patients with Symptomatic Lumbar Spinal Stenosis

OBJECTIVE

We performed a retrospective cohort study to investigate the prevalence of and risk factors for asymptomatic spondylotic cervical spinal stenosis (ASCSS) in the setting of lumbar spinal stenosis (LSS).

METHODS

A total of 114 patients with a diagnosis of LSS without cervical myelopathy and radiculopathy were grouped into ASCSS and non-ASCSS groups. The medical data and radiological parameters, including age, sex, body mass index, Charlson comorbidity index, symptom duration, redundant nerve roots, dural sac cross-sectional area (DCSA), facet joint angle, lumbar lordosis angle (LLA), pelvic incidence (PI), Torg-Pavlov ratio, and lumbosacral transitional vertebrae, were analyzed. The lumbar stenosis index and cervical stenosis index of the 114 patients were also analyzed.

RESULTS

ASCSS occurred in 70 of the 114 patients with LSS (61.4%). The two groups showed significant differences in symptom duration, redundant nerve roots, LLA, DCSA, and PI. On multivariate logistic regression analysis, an LLA >35.85° (P < 0.001) and a DCSA <84.50 mm² (P = 0.003) were independently associated with ASCSS. The multi-index receiver operating characteristic curve showed that the area under the curve for predicted probability was 0.805 (P < 0.001). Linear regression analysis revealed that cervical stenosis index significantly and positively correlated with the lumbar stenosis index (r = 0.430; P < 0.001).

CONCLUSIONS

Our findings suggest that an LLA >35.85° and a DCSA <84.50 mm² are risk factors for the development of ASCSS. For LSS patients with an enlarged LLA and reduced DSCA, a whole spinal magnetic resonance imaging examination should be performed.

Sex-Dependent Differences in Symptom-Related Disability Due to Lumbar Spinal Stenosis

Study Design

Retrospective observational study.

Objective

The objective of this study is to identify possible sex-dependent differences in symptom-related disability in patients with lumbar spinal stenosis.

Methods

103 consecutive outpatients (42 men and 61 women) with lumbar spinal stenosis were assessed on the basis of their medical history, the physical examination, and a series of questionnaires including the Oswestry Disability Index (ODI), the Roland Morris Disability Questionnaire (RMDQ), the Patient Health Questionnaire module 9 (PHQ-9), and the Depression Anxiety Stress Scales (DASS). Narrowing of the spinal canal was graded according to the method established by Schizas. Parameters were statistically analyzed according to the biological sex of the patients. The influence of the variables on the disability scores was analyzed by means of a multivariate regression model.

Results

Symptom severity was equally distributed between men and women. Female patients showed higher RMDQ and ODI scores as well as significantly higher intermediate depression scores. The confounding variables age, pain chronicity, and psychological affection as well as the symptoms level of pain and paresis were dependent on patient sex.

Conclusion

The study shows sex-depended differences in the perception of symptoms of lumbar spinal stenosis and disability of life. The findings suggest that the main mediators are pain perception and psychological influences on the quality of life.

Predictability of the effects of epidural injection in lumbar spinal stenosis by assessment of lumbar MRI scans

BACKGROUND

Numerous classification systems have been proposed to interpret lumbar MRI scans. The clinical impact of the measured parameters remains unclear. To evaluate the clinical significance of imaging results in patients with multisegmental degenerative pathologies, treating specialists can perform image-guided local injections to target defined areas such as the epidural space.

OBJECTIVE

The aim of this retrospective study was to evaluate the correlation between lumbar spinal stenosis measurements obtained by MRI and improvement obtained through local epidural injection.

METHODS

In this retrospective study various measurement and classification systems for lumbar spinal stenosis were applied to MRI scans of 100 patients with this pathological condition. The reported effect of epidural bupivacaine/triamcinolone injections at the site was recorded in these patients and a comparative analysis performed.

RESULTS

MRI features assessed in this study did not show any relevant correlation with reported pain relief after epidural injection in patients with chronic lumbar stenosis, with the exception of posterior disc height with a weak Kendall's tau of -0.187 (p= 0.009).

CONCLUSIONS

Although MRI is crucial for evaluating lumbar spinal stenosis, it cannot replace but is rather complementary to a good patient history and clinical examination or the results of local diagnostic injections.

Evaluation of the Minimum Clinically Important Differences of the Zurich Claudication Questionnaire in Patients With Lumbar Spinal Stenosis

STUDY DESIGN

A case-control study.

OBJECT

This study aimed to evaluate the minimally clinically important differences (MCIDs) of the Zurich Claudication Questionnaire (ZCQ) after microendoscopic laminectomy in patients with lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

The ZCQ is a self-administered tool used to evaluate symptom severity and physical function in patients with LSS. It has been used in many studies worldwide. However, the MCIDs of the ZCQ have not yet been determined.

MATERIALS AND METHODS

The study sample consisted of 514 patients who underwent microendoscopic laminectomy for LSS at our hospital between March 2012 and May 2014. The ZCQ, which includes 7 items for symptom severity (scored from 1 to 5) and 5 items for functional disability (scored from 1 to 4), was administered preoperatively and 1-year postoperatively. The MCID was calculated by 4 approaches, including average change, minimum detectable change, change difference, and receiver operating characteristic curve. The authors calculated the area under the curve (AUC) to evaluate the accuracy of the receiver operating characteristic curve. The responsiveness of each measurement was then analyzed.

RESULTS

The authors were able to administer the ZCQ at 1-year postoperatively in 349 patients. The ZCQ score was statistically significantly improved 1-year postoperatively. The MCID of ZCQ for symptom severity varied from 0.75 to 0.84, whereas the MCID of the ZCQ score for functional disability varied from 0.60 to 0.76. The AUC of the ZCQ for symptom severity was 0.81 and that for functional disability was 0.80.

CONCLUSIONS

This study showed that the MCID of the ZCQ for symptom severity varied from 0.75 to 0.84 and the MCID for functional disability varied from 0.60 to 0.76. In addition, each AUC was over 0.80, indicating that MCIDs of the ZCQ were found to have a high diagnostic performance.

Prevalence of lumbar spinal stenosis in general and clinical populations: a systematic review and meta-analysis

PURPOSE

To estimate the prevalence of degenerative lumbar spinal stenosis (LSS) in adults, identified by clinical symptoms and/or radiological criteria.

METHODS

Systematic review of the literature. Pooled prevalence estimates by care setting and clinical or radiological diagnostic criteria were calculated and plotted [PROSPERO ID: CRD42018109640].

RESULTS

In total, 41 papers reporting on 55 study samples were included. The overall risk of bias was considered high in two-thirds of the papers. The mean prevalence, based on a clinical diagnosis of LSS in the general population, was 11% (95% CI 4-18%), 25% (95% CI 19-32%) in patients from primary care, 29% (95% CI 22-36%) in patients from secondary care and 39% (95% CI 39-39%) in patients from mixed primary and secondary care. Evaluating the presence of LSS based on radiological diagnosis, the pooled prevalence was 11% (95% CI 5-18%) in the asymptomatic population, 38% (95% CI - 10 to 85%) in the general population, 15% (95% CI 13-18%) in patients from primary care, 32% (95% CI 22-41%) in patients from secondary care and 21% (95% CI 16-26%) in a mixed population from primary and secondary care.

CONCLUSIONS

The mean prevalence estimates based on clinical diagnoses vary between 11 and 39%, and the estimates based on radiological diagnoses similarly vary between 11 and 38%. The results are based on studies with high risk of bias, and the pooled prevalence estimates should therefore be interpreted with caution. With an growing elderly population, there is a need for future low risk-of-bias research clarifying clinical and radiological diagnostic criteria of lumbar spinal stenosis. These slides can be retrieved under Electronic Supplementary Material.

Treatment for lumbar spinal stenosis secondary to ligamentum flavum hypertrophy using percutaneous endoscopy through interlaminar approach: a retrospective study

Background

This paper is to describe percutaneous endoscopy in the treatment of lumbar spinal stenosis secondary to ligamentum flavum hypertrophy targeted and to investigate the efficacy and safety of percutaneous endoscopy in the treatment of this kind of lumbar spinal stenosis in elderly patients.

Method

A retrospective analysis of 40 elderly patients with lumbar spinal stenosis secondary to ligamentum flavum hypertrophy admitted between January 2016 and January 2018 was performed. According to different surgical methods, they were divided into two groups: the control group and the endoscopy group (interlaminar approach), 20 people per group. There were 9 males and 11 females in the control group; the age of patients was 65.65 ± 4.44 years, and the average disease duration was 4.55 ± 1.85 years. Besides, there were 10 males and 10 females in the endoscopy group; the age of patients was 67.30 ± 4.23 years, and the average disease duration was 4.95 ± 2.04 years. Collect and count surgical-related indicators, preoperative and postoperative radiologic findings, incision visual analog scale (VAS), lumbar and leg pain VAS, lumbar Japanese Orthopaedic Association (JOA), and Oswestry disability index (ODI) scores of all patients.

Result

A series of surgical indicators (including the operation time, the quantity of bleeding, and postoperative hospital stay) in the endoscopy group was significantly lower than that in the control group (p < 0.05). The incision VAS score in the endoscopy group was also significantly lower than that in the control group at each time after surgery (p < 0.05). Besides, compared with the control group, in the endoscopy group, the leg pain VAS score and lumbar ODI score after surgery were significantly decreased (p < 0.05). Compared with the control group, in the endoscopy group, the lumbar JOA score was significantly higher (p < 0.05).

Conclusion

Percutaneous endoscopic technique is a small trauma, quick recovery, safe, and effective minimally invasive surgery for patients with lumbar spinal stenosis secondary to ligamentum flavum hypertrophy.

Clinical validity of two different grading systems for lumbar central canal stenosis: Schizas and Lee classification systems

OBJECTIVE

To assess the learnability of two magnetic resonance imaging (MRI) grading systems for lumbar central canal stenosis based on inter-observer agreement and test-retest reliability of doctors with no prior knowledge of the two systems.

MATERIALS AND METHODS

Two clinical fellows, one novice radiology resident, one neurosurgeon, and one orthopedic surgeon, who were unaware of the two qualitative MRI grading systems prior to this study, acquainted themselves with the teaching files. All five observers independently assessed the LCCS grade of 70 patients using T2-weighted axial magnetic resonance images at the L2-3, L3-4, L3-4, and L5-S1 disc levels. Analysis was performed twice at an interval of two months.

RESULTS

The inter-observer agreement among all five readers was excellent and test-retest reliability was moderate to excellent for both the Schizas and Lee systems. Positive percentage agreements were found to be over 0.8 in almost all observers with relatively narrow 95% confidence limits.

CONCLUSION

Both Schizas and Lee MRI grading systems for LCCS are reliable grading systems, and can be used as a learnable method for both clinicians and radiologists.

Usefulness of the Inferior Articular Process's Cross-Sectional Area as a Morphological Parameter for Predicting Central Lumbar Spinal Stenosis

Hypertrophy of facet joints is associated with a high risk of central lumbar spinal stenosis (CLSS). However, no research has reported the effect of inferior articular process hypertrophy in CLSS. We hypothesize that the inferior articular process’s cross-sectional area (IAPCSA) is larger in patients with CLSS compared to those without CLSS. Data on IAPCSA were obtained from 116 patients with CLSS. A total of 102 control subjects underwent lumbar spine magnetic resonance imaging (LS-MRI) as part of a routine medical examination. Axial T1-weighted images were obtained from the two groups. Using an imaging analysis system, we investigated the cross-sectional area of the inferior articular process. The average IAPCSA was 70.97 ± 13.02 mm² in control subjects and 88.77 ± 18.52 mm² in patients with CLSS. CLSS subjects had significantly greater levels of IAPCSA (p < 0.001) than controls. A receiver operating characteristic (ROC) curve was plotted to determine the validity of IAPCSA as a predictor of CLSS. The most suitable cut-off point of IAPCSA for predicting CLSS was 75.88 mm², with a sensitivity of 71.6%, a specificity of 68.6%, and an area under the curve (AUC) of 0.78 (95% CI: 0.72–0.84). Greater IAPCSA levels were associated with a higher incidence of CLSS. These results demonstrate that IAPCSA is a useful morphological predictor in the evaluation of CLSS.

Increased pain and sensory hyperinnervation of the ligamentum flavum in patients with lumbar spinal stenosis

Nociceptive sensory nerve fibers have never been investigated in the ligamentum flavum (LF) of patients with LSS. The aim was to analyze nociceptive sensory nerve fibers in the ligamentum flavum (LF) of patients with LSS. A prospective study in patients with lumbar spinal stenosis (LSS) undergoing invasive surgical treatment for lumbar spinal stenosis (LSS) with flavectomy was performed. Patients with LSS were subjected to flavectomy and density of sensory and sympathetic nerve fibers, macrophages, vessels, activated fibroblasts, and cells were investigated by immunostaining techniques. A group of patients with acute disc herniation served as control group. We found a higher density of sensory nerve fibers in LSS patients versus controls. These findings support the role of LF in associated low back pain. Density of sensory nerve fibers in LSS, was positively correlated with typical markers of clinical pain and functional disability, but not with LF density of activated fibroblasts. Inflammation as estimated by macrophage infiltration and higher vascularity does not play a marked role in LF in our LSS patients. In the present study, compared to men with LSS, women with LSS demonstrate more pain and depression, and show a higher density of sensory nerve fibers in LF. This study shed new light on nociceptive nerve fibers, which are increased in LSS compared to controls. The findings speak against a strong inflammatory component in LSS. A higher pain levels in women compared to men can be explained by a higher density of nociceptive nerve fibers. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-7, 2019.

Superior articular process cross-sectional area is a new sensitive parameter for the diagnosis of lumbar central canal spinal stenosis

Purpose

Previous studies reported that hypertrophied superior articular process (SAP) was associated with an increased risk of lumbar foraminal stenosis. However, no study investigated the effect of SAP hypertrophy in lumbar central canal spinal stenosis (LCCSS). We hypothesized that the SAP cross-sectional area (SAPCSA) is the main morphologic feature in the diagnosis of LCCSS.

Patients and methods

Data regarding the SAPCSA were collected from 109 patients with LCCSS. All patients were enrolled after the LCCSS diagnosis was confirmed by an experienced, board-certified neuroradiologist. All patients had clinical manifestations compatible with LCCSS. A total of 120 subjects in the control group underwent lumbar spine MRI as part of non-symptomatic medical examination. T2-weighted axial images were obtained from the 2 groups. Using a picture archiving and communications system, we analyzed the CSA of the bone margin of SAP at the level of L4–L5 facet joint on MRI.

Results

The average SAPCSA was 96.63±13.37 mm² in the control group, and 123.59±14.18 mm² in the LCCSS. The LCCSS group showed significantly higher levels of the SAPCSA (P<0.001) compared with the control one. Receiver operator characteristic (ROC) curve analysis was performed to determine the validity of the SAPCSA as a predictor of LCCSS. In the LCCSS group, the optimal cut-off-point was 110.71 mm², with 83.5% sensitivity, 83.3% specificity, and area under the curve of 0.92 (95% CI: 0.88–0.95).

Conclusion

Higher SAPCSA values were associated with a higher possibility of LCCSS. These results are important in the evaluation of patients with LCCSS.

Is there a Correlation Between Degree of Radiologic Lumbar Spinal Stenosis and its Clinical Manifestation?

STUDY DESIGN

This was an observational cross-sectional study.

OBJECTIVE

The purpose of this study was to evaluate whether the degree of stenosis on magnetic resonance imaging (MRI) relates to the severity of clinical symptoms, disability, or neurological deficit in patients with symptomatic central lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

The relationship between radiologic findings and the clinical manifestations of LSS remains unclear.

MATERIALS AND METHODS

A total of 84 patients (42 men, median age 70 y) with neurogenic claudication and central degenerative LSS were included in the study. The MRI parameters describing severity (anteroposterior diameter of dural sac, cross-sectional area of the dural sac, stenosis ratio, and Schizas qualitative morphologic classification were evaluated at maximum stenotic level) and the extent of stenosis (the number of central stenotic levels) were correlated to symptoms (pain intensity, walking capacity), functional disability (measured in terms of the Oswestry Disability Index), and neurological signs of LSS (neurological status was evaluated and scored by Neurological Impairment Score in LSS).

RESULTS

A statistically significant correlation emerged only between the Neurological Impairment Score in LSS and Schizas morphologic classification (P=0.006). Pain intensity, walking capacity, and functional disability displayed no correlation with the MRI parameters of LSS.

CONCLUSIONS

LSS is a clinicoradiologic syndrome with complex relationships between degree of radiologic stenosis disclosed by MRI and clinical manifestations. Neurological impairment in the lower extremities reflects the degree of morphologic LSS on MRI. This study did not identify any association between the degree of stenosis and functional disability, pain intensity, or walking capacity.

LEVEL OF EVIDENCE

Level II.

Optimal cut-off points of lumbar pedicle thickness as a morphological parameter to predict lumbar spinal stenosis syndrome: a retrospective study

Purpose

Lumbar spinal stenosis syndrome (LSSS) is induced by factors such as ligamentum flavum hypertrophy, facet joint hypertrophy and disc degeneration. However, the role of lumbar pedicle (LP) in LSSS has yet to be evaluated. We devised a new morphological parameter called the lumbar pedicle thickness (LPT) to evaluate the connection between LSSS and the LP. We hypothesized that the LPT is a major morphological parameter in the diagnosis of LSSS.

Patients and methods

The LPT data were collected from 136 patients diagnosed with LSSS. A total of 99 control subjects underwent lumbar spine magnetic resonance imaging (MRI) as part of a detailed medical assessment. Axial T2-weighted magnetic resonance (MR) images were acquired from all the participants. Using our picture archiving and communication system, we analyzed the thickness of the LP at the level of L5 vertebra on MRI.

Results

The average LPT was 9.46±1.81 mm in the control group and 13.26±1.98 mm in the LSSS group. LSSS patients showed a significantly greater LPT (P<0.001) than the control group. The receiver operating characteristic (ROC) curve analysis showed an optimal cutoff point of 11.33 mm for the LPT, with 83.8% sensitivity, 83.8% specificity and area under the curve of 0.92 (95% confidence interval [CI], 0.89-0.96).

Conclusion

A higher LPT was associated with a higher possibility of LSSS, suggesting its importance in the evaluation of patients with LSSS.

Predictive factors of symptomatic lumbar canal stenosis in patients after surgery for cervical spondylotic myelopathy

Background

The aim of this study was to determine the incidence of coexisting symptomatic lumbar canal stenosis (LCS) in patients after surgery for cervical spondylotic myelopathy (CSM) and identify possible predictive factors associated with it.

Materials and methods

We retrospectively reviewed patients with CSM at our institution between January 2005 and December 2015. Clinical and radiographic factors including age, gender, body mass index, Japanese Orthopedic Association scores, cervical alignment, anteroposterior diameter of cervical canal, number of levels with CSM, and percentage of cervical cord compression were investigated. Symptomatic LCS was defined as leg symptoms and a narrowing of the lumbar spinal canal at one level at least, which is confirmed by magnetic resonance images of the lumbar spine. Univariate and multivariate analyses were used to identify possible predictive factors. Pearson correlation analysis was also conducted to analyze the association between cervical parameters and percentage of LCS.

Results

A total of 317 patients with CSM met the criteria for inclusion. There were 39 patients (12.3%) with LCS after cervical surgery during a mean of 7.3 years’ follow-up. In the multivariate logistic regression analysis, narrow diameter of cervical canal (OR, 3.96; 95% CI, 1.20–13.04) was identified as the only independent predictor of symptomatic LCS in CSM patients. The correlation coefficient between anteroposterior diameter of cervical canal and severity of LCS indicated a significantly positive linear relationship with 0.536 (P<0.001).

Conclusion

We found that narrow diameter of cervical canal was associated with symptomatic LCS in CSM patients. Patients with this risk factor should be informed the possibility of symptomatic LCS.

Dural sac area is a more sensitive parameter for evaluating lumbar spinal stenosis than spinal canal area: A retrospective study

Narrowing of the dural sac cross-sectional area (DSCSA) and spinal canal cross-sectional area (SCCSA) have been considered major causes of lumbar central canal spinal stenosis (LCCSS). DSCSA and SCCSA were previously correlated with subjective walking distance before claudication occurs, aging, and disc degeneration. DSCSA and SCCSA have been ideal morphological parameters for evaluating LCCSS. However, the comparative value of these parameters is unknown and no studies have evaluated the clinical optimal cut-off values of DSCSA and SCCSA. This study assessed which parameter is more sensitive.Both DSCSA and SCCSA samples were collected from 135 patients with LCCSS, and from 130 control subjects who underwent lumbar magnetic resonance imaging (MRI) as part of a medical examination. Axial T2-weighted MRI scans were acquired at the level of facet joint from each subject. DSCSA and SCCSA were measured at the L4-L5 intervertebral level on MRI using a picture archiving and communications system.The average DSCSA value was 151.67 ± 53.59 mm in the control group and 80.04 ± 35.36 mm in the LCCSS group. The corresponding average SCCSA values were 199.95 ± 60.96 and 119.17 ± 49.41 mm. LCCSS patients had significantly lower DSCSA and SCCSA (both P < .001). Regarding the validity of both DSCSA and SCCSA as predictors of LCCSS, Receiver operating characteristic curve analysis revealed an optimal cut-off value for DSCSA of 111.09 mm, with 80.0% sensitivity, 80.8% specificity, and an area under the curve (AUC) of 0.87 (95% confidence interval, 0.83-0.92). The best cut off-point of SCCSA was 147.12 mm, with 74.8% sensitivity, 78.5% specificity, and AUC of 0.85 (95% confidence interval, 0.81-0.89).DSCSA and SCCSA were both significantly associated with LCCSS, with DSCSA being a more sensitive measurement parameter. Thus, to evaluate LCCSS patients, pain specialists should more carefully investigate the DSCSA than SCCSA.

Predictability of the effects of facet joint infiltration in the degenerate lumbar spine when assessing MRI scans

Background

Imaging results are frequently considered as hallmarks of disease by spine surgeons to plan their future treatment strategy. Numerous classification systems have been proposed to quantify or grade lumbar magnetic resonance imaging (MRI) scans and thus objectify imaging findings. The clinical impact of the measured parameters remains, however, unclear. To evaluate the pathological significance of imaging findings in patients with multisegmental degenerative findings, clinicians can perform image-guided local infiltrations to target defined areas such as the facet joints.

The aim of the present retrospective study was to evaluate the correlation of MRI facet joint degeneration and spinal stenosis measurements with improvement obtained by image-guided intraarticular facet joint infiltration.

Methods

Fifty MRI scans of patients with chronic lumbar back pain were graded radiologically using a wide range of classification and measurement systems. The reported effect of facet joint injections at the site was recorded, and a comparative analysis performed.

Results

When we allocated patients according to their reported pain relief, 27 showed no improvement (0–30%), 16 reported good improvement (31–75%) and 7 reported excellent improvement (> 75%). MRI features assessed in this study did, however, not show any relevant correlation with reported pain after facet joint infiltration: Values for Kendall’s tau ranged from τ = − 0.190 for neuroforaminal stenosis grading as suggested by Lee, to τ = 0.133 for posterior disc height as proposed by Hasegawa.

Conclusion

Despite the trend in evidence-based medicine to provide medical algorithms, our findings underline the continuing need for individualised spine care that, along with imaging techniques or targeted infiltrations, includes diagnostic dimensions such as good patient history and clinical examination to formulate a diagnosis.

Trial registration

ClinicalTrials.gov, NCT03308149, retrospectively registered October 2017

Electronic supplementary material

The online version of this article (10.1186/s13018-017-0685-x) contains supplementary material, which is available to authorized users.

Dural sac cross-sectional area and morphological grade show significant associations with patient-rated outcome of surgery for lumbar central spinal stenosis

PURPOSE

Lumbar central spinal stenosis (LSS) is one of the most common reasons for spine surgery in the elderly patient. Magnetic resonance imaging (MRI) represents the gold standard for the assessment of LSS and can be used to obtain quantitative measures of the dural sac cross-sectional area (DCSA) or qualitative measures (morphological grades A-D) of the rootlet/cerebrospinal fluid ratio. This study investigated the intercorrelation between these two MRI evaluation methods and explored their respective relationships with the patient baseline clinical status and outcome 12 months after surgery.

METHODS

This was a retrospective analysis of prospectively collected data from 157 patients (88 male, 69 female; age 72 ± 7 years) who were undergoing first-time surgery for LSS. Patients with foraminal or isolated lateral stenosis were excluded. The Core Outcome Measures Index (COMI) was completed before and 12 months after surgery. Preoperative T2 axial MRIs were blinded and independently evaluated for DCSA and morphological grade. Spearman rank correlation coefficients described the relationship between the two MRI measures of stenosis severity and between each of these and the COMI baseline and change-scores (pre to 12 months' postop). Multiple logistic regression analysis (controlling for baseline COMI, age, gender, number of operated levels, health insurance status) was used to analyse the influence of stenosis severity on the achievement of the minimum clinically important change (MCIC) score for COMI and on global treatment outcome (GTO).

RESULTS

There was a correlation of ρ = -0.69 (p < 0.001) between DCSA and morphological grade. There was no significant correlation between COMI baseline scores and either DCSA or morphological grades (p > 0.85). However, logistic regression revealed significant (p < 0.05) associations between stenosis ratings and 12-month outcome, whereby patients with more severe stenosis (as measured using either of the methods) benefited more from the surgery. Patients with a DCSA <75 mm² or morphological grade D had a 4-13-fold greater odds of achieving the MCIC for COMI or a "good" GTO, compared with patients in the least severe categories of stenosis.

CONCLUSIONS

Postoperative outcome was clearly related to the degree of preoperative radiological LSS. The two MRI methods appeared to deliver similar information, as given by the relatively strong correlation between them and their comparable performance in relation to baseline and 12-month outcomes. However, the qualitative morphological grading can be performed in an instant, without measurement tools, and does not deliver less clinically useful information than the more complex and time-consuming measures; as such, it may represent the preferred method in the clinical routine for assessing the extent of radiological stenosis and the likelihood of a positive outcome after decompression.

Association between paraspinal muscle morphology, clinical symptoms and functional status in patients with lumbar spinal stenosis

PURPOSE

Lumbar spinal stenosis (LSS) is a disabling condition associated with narrowing of the spinal canal or vertebral foramina. Paraspinal muscle atrophy and fatty infiltration have been reported in patients with chronic LBP and disc herniation. However, very few imaging studies have examined paraspinal muscle morphology and composition in patients with LSS. The purpose of this study was to investigate the association of paraspinal muscle size, composition and asymmetry with functional status in patients with LSS.

METHODS

Thirty-six patients diagnosed with LSS at L4-L5 with neurogenic claudication were included. Paraspinal muscle measurements were obtained from axial T2-weighted MR images, bilaterally, at the level of the superior and inferior vertebral endplates of L5. Muscle measurements of interest included: total cross-sectional area (CSA), functional CSA (FCSA), the ratio of FCSA to CSA (FCSA/CSA) as an indicator of muscle composition, and relative % asymmetry in muscle CSA. The association between muscle parameters and other patient characteristics with function as indicated from Oswestry Disability Index (ODI) scores and pain interference status was investigated.

RESULTS

Greater multifidus muscle fatty infiltration (e.g., lower FCSA/CSA) and lower psoas relative CSA were associated with lower function (higher ODI and pain interference scores) in univariable and multivariable analyses. There was no association between the different muscle parameters and stenosis severity or back or leg pain duration or severity.

CONCLUSIONS

Our findings suggest an association of multifidus muscle fatty infiltration and psoas muscle size with functional status in patients diagnosed with LSS. Future prospective studies are needed to evaluate whether such muscle parameters are associated with prognosis and functional recovery following surgical treatment.

Management of degenerative lumbar spinal stenosis: an evidence-based review

Lumbar spinal stenosis has become one of the most disabling pathologies in the elderly population.Some additional conditions such as foraminal stenosis or degenerative spondylosis with a history of back pain and leg pain must be considered before treatment.A completely appropriate protocol and unified management of spinal stenosis have not yet been well defined.The objective of this literature review is to provide evidence-based recommendations reflected in the highest-quality clinical literature available to address key clinical questions surrounding the management of degenerative lumbar spinal stenosis. Cite this article: Covaro A, Vilà-Canet G, García de Frutos A, Ubierna MT, Ciccolo F, Caceres E. Management of degenerative lumbar spinal stenosis: an evidence-based review article. EFORT Open Rev 2016;1:267-274. DOI: 10.1302/2058-5241.1.000030.

Optimal Cut-Off Value of the Superior Articular Process Area as a Morphological Parameter to Predict Lumbar Foraminal Stenosis

Background. We devised a new morphological parameter called the superior articular process area (SAPA) to evaluate the connection between lumbar foraminal stenosis (LFS) and the superior articular process. Objective. We hypothesized that the SAPA is an important morphologic parameter in the diagnosis of LFS. Methods. All patients over 60 years of age were included. Data regarding the SAPA were collected from 137 patients with LFS. A total of 167 control subjects underwent lumbar magnetic resonance imaging (MRI) as part of a routine medical examination. We analyzed the cross-sectional area of the bone margin of the superior articular process at the level of L4-L5 facet joint in the axial plane. Results. The average SAPA was 96.3 ± 13.6 mm² in the control group and 128.1 ± 17.2 mm² in the LFS group. The LFS group was found to have significantly higher levels of SAPA (p < 0.001) in comparison to the control group. In the LFS group, the optimal cut-off value was 112.1 mm², with 84.4% sensitivity, 83.9% specificity, and AUC of 0.94 (95% CI: 0.91-0.96). Conclusions. Higher SAPA values were associated with a higher possibility of LFS. These results are important in the evaluation of patients with LFS.

Radiographic assessment of degenerative lumbar spinal stenosis: is MRI superior to CT?

OBJECTIVE

To determine the reliability and dependability of magnetic resonance imaging (MRI) and computerized tomography (CT) in the assessment of lumbar spinal stenosis and correlate the qualitative assessment to both a quantitative assessment and functional outcome measures. Multiple studies have addressed the issue of CT and MRI imaging in lumbar spinal stenosis. None showed superiority of one modality.

METHODS

We performed a standardized qualitative and quantitative review of CT and MRI scans of 54 patients. Intra-observer and inter-observer reliability was determined between three reviewer using Kappa coefficient. Agreement between the two modalities was analyzed. ODI and SF-36 outcomes were correlated with the imaging assessments.

RESULTS

Almost perfect intra-observer reliability for MRI was achieved by the two expert reviewers (κ = 0.91 for surgeon and κ = 0.92 for neuro-radiologist). For CT, substantial intra-observer agreement was found for the surgeon (κ = 0.77) while the neuro-radiologist was higher (κ = 0.96). For both CT and MRI the standardized qualitative assessment used by the two expert reviewers had a better inter-observer reliability than that between the expert reviewers and the general reporting radiologist, who did not utilize a standardized assessment system. When the qualitative assessment was compared directly, CT overestimated the degree of stenosis 20-35 % of the time (p < 0.05) while MRI overestimated the degree of stenosis 2-11 % of the time (p < 0.05). No correlation was found between qualitative and quantitative analysis with functional status.

CONCLUSIONS

This study directly demonstrates that MRI is a more reliable tool than CT, but neither correlates with functional status. Both experience of the reader and the standardization of a qualitative assessment are influential to the reliability.

Degenerative lumbar spinal canal stenosis: intra- and inter-reader agreement for magnetic resonance imaging parameters

PURPOSE

To assess the inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of degenerative lumbar spinal canal stenosis (LSS) by magnetic resonance imaging (MRI).

METHODS

In this ethical board approved cross-sectional multicenter study, MRI of 100 randomly selected patients (median age 72.5 years, 48 % female) of the prospective Lumbar Stenosis Outcome Study (LSOS) were evaluated by two independent readers. A set of five previously published core imaging parameters as well as nine qualitative and five quantitative additional parameters regarding LSS and degenerative changes of the lumbar spine were assessed to calculate κ and intraclass correlation coefficients (ICC) for the inter-reader agreement. Additional repeated image evaluations were performed by one reader to calculate the intra-reader agreement.

RESULTS

κ values for the core image parameters ranged between 0.42 (compromise of the foraminal zone) and 0.77 (relation between fluid and cauda equina) for inter-reader agreement and between 0.59 (compromise of the foraminal zone) and 0.8 (compromise of the central zone) for intra-reader agreement. The inter-reader agreement for the non-core parameters showed κ values of 0.27-0.69 and ICC values of 0.46-0.85. The intra-reader agreement showed κ values of 0.53-0.69 and ICC values of 0.81-0.88.

CONCLUSIONS

The inter- and intra-reader agreement of commonly used quantitative and qualitative image parameters for the assessment of LSS showed quite a variability with previously defined core parameters having good to excellent inter- and intra-reader agreements.

Ablation of porcine ligamentum flavum with Ho:YAG, q-switched Ho:YAG, and quadrupled Nd:YAG lasers

BACKGROUND AND OBJECTIVES

Ligamentum flavum (LF) is a tough, rubbery connective tissue providing a portion of the ligamentous stability to the spinal column, and in its hypertrophied state forms a significant compressive pathology in degenerative spinal stenosis. The interaction of lasers and this biological tissue have not been thoroughly studied. Technological advances improving endoscopic surgical access to the spinal canal makes selective removal of LF using small, flexible tools such as laser-coupled fiber optics increasingly attractive for treatment of debilitating spinal stenosis. Testing was performed to assess the effect of Ho:YAG, Q-switched Ho:YAG, and frequency quadrupled Nd:YAG lasers on samples of porcine LF. The objective was to evaluate the suitability of these lasers for surgical removal of LF.

STUDY DESIGN/MATERIALS AND METHODS

LF was resected from porcine spine within 2 hours of sacrifice and stored in saline until immediately prior to laser irradiation, which occurred within an additional 2 hours. The optical absorbance of a sample was measured over the spectral band from 190 to 2,360 nm both before and after dehydration. For the experiments using the Ho:YAG (λ = 2,080 nm, tp  = 140 µs, FWHM) and Q-Switched Ho:YAG (λ = 2,080 nm, tp  = 260 ns, FWHM) lasers, energy was delivered to the LF through a laser-fiber optic with 600 µm core and NA = 0.39. For the experiment using the frequency quadrupled Nd:YAG laser (λ = 266 nm, tp  = 5 ns FWHM), rather than applying the laser energy through a laser-fiber, the energy was focused through an aperture and lens directly onto the LF. Five experiments were conducted to evaluate the effect of the given lasers on LF. First, using the Ho:YAG laser, the single-pulse laser-hole depth versus laser fluence was measured with the laser-fiber in direct contact with the LF (1 g force) and with a standoff distance of 1 mm between the laser-fiber face and the LF. Second, with the LF remaining in situ and the spine bisected along the coronal plane, the surface temperature of the LF was measured with an IR camera during irradiation with the Ho:YAG laser, with and without constant saline flush. Third, the mass loss was measured over the course of 450 Ho:YAG pulses. Fourth, hole depth and temperature were measured over 30 pulses of fixed fluence from the Ho:YAG and Q-Switched Ho:YAG lasers. Fifth, the ablation rate and surface temperature were measured as a function of fluence from the Nd:YAG laser. Several LF staining and hole-depth measurement techniques were also explored.

RESULTS

Aside from the expected absorbance peaks corresponding to the water in the LF, the most significant peaks in absorbance were located in the spectral band from 190 to 290 nm and persisted after the tissue was dehydrated. In the first experiment, using the Ho:YAG laser and with the laser-fiber in direct contact with the LF, the lowest single-pulse fluence for which LF was visibly removed was 35 J/cm(2) . Testing was conducted at 6 fluences between 35 and 354 J/cm(2) . Over this range the single-pulse hole depth was shown to be near linear (R(2)  = 0.9374, M = 1.6), ranging from 40 to 639 µm (N = 3). For the case where the laser-fiber face was displaced 1 mm from the LF surface, the lowest single-pulse fluence for which tissue was visibly removed was 72 J/cm(2) . Testing was conducted at 4 energy densities between 72 and 180 J/cm(2) . Over this range the single-pulse hole depth was shown to be near linear (R(2)  = 0.8951, M = 1.4), ranging from 31 to 220 µm (N = 3). In the second experiment, with LF in situ, constant flushing with room temperature saline was shown to drastically reduce surface temperature during exposure to Ho:YAG at 5 Hz with the laser-fiber in direct contact with the LF. Without saline, over 1 minute of treatment with a per-pulse fluence of 141 mJ/cm(2) , the average maximum surface temperature measured 110°C. With 10 cc's of saline flushed over 1 minute and a per-pulse laser fluence of 212 mJ/cm(2) , the average maximum surface temperature was 35°C. In the third experiment, mass loss was shown to be linear over 450 pulses of 600 mJ from the Ho:YAG laser (212 J/cm(2) , direct contact, N = 4; 108 J/cm(2) , 1 mm standoff, N = 4). With the laser-fiber in direct contact, an average of 53 mg was removed (R(2)  = 0.996, M = 0.117) and with 1 mm laser-fiber standoff, an average of 44 mg was removed (R(2)  = 0.9988, M = 0.097). In the fourth experiment, 30 pulses of the Ho:YAG and Q-Switched Ho:YAG lasers at 1 mm standoff, and 5 Hz produced similar hole depths for the tested fluences of 9 J/cm(2) (151 and 154 µm, respectively) and 18 J/cm(2) (470 and 442 µm, respectively), though the Ho:YAG laser produced significantly more carbonization around the rim of the laser-hole. The increased carbonization was corroborated by higher measured LF temperature. In all tests with the Ho:YAG and Q-Switched Ho:YAG, an audible photo-acoustic affect coincided with the laser pulse. In the fifth experiment, with the frequency quadrupled Nd:YAG laser at 15 Hz for 450 pulses, ablation depth per pulse was shown to be linear for the fluence range of 0.18 - 0.73 J/cm(2) (R(2)  = 0.989, M = 2.4). There was no noticeable photo-acoustic effect nor charring around the rim of the laser-hole.

CONCLUSION

The Ho:YAG, Q-Switched Ho:YAG, and frequency quadrupled Nd:YAG lasers were shown to remove ligamentum flavum (LF). A single pulse of the Ho:YAG laser was shown to cause tearing of the tissue and a large zone of necrosis surrounding the laser-hole. Multiple pulses of the Ho:YAG and Q-Switched Ho:YAG lasers caused charring around the rim of the laser-hole, though the extent of charring was more extensive with the Ho:YAG laser. Charring caused by the Ho:YAG laser was shown to be mitigated by continuously flushing the affected LF with saline during irradiation. The Nd:YAG laser was shown to ablate LF with no gross visible indication of thermal damage to surrounding LF.