Diffuse idiopathic skeletal hyperostosis is associated with lumbar spinal stenosis requiring surgery

Spatiotemporal changes in imaging features associated with diffuse idiopathic skeletal hyperostosis (DISH)

OBJECTIVES

The purpose of our study was to characterise spatiotemporal features of disease progression in people with diffuse idiopathic skeletal hyperostosis (DISH), early-phase DISH, and those not meeting either criterion who had repeated CT scans of the thoracic spine.

METHODS

A retrospective study was designed in collaboration with the Rochester Epidemiology Project to evaluate completeness of ectopic bridging across the thoracic spine and corresponding disease status over an average of 2.7 years (range from 0.2 to 15.0 years) in a cohort of 83 female and 74 male individuals.

RESULTS

Over 15% of individuals displayed changes in imaging features over time that resulted in a revised diagnosis along the continuum of DISH. Early-phase DISH was marked by new involvement of previously unaffected motion segments, estimated to occur over 2.1 years. Advanced presentations of DISH were marked by increased prevalence of complete bridging (average two of three available motion segments), estimated to occur over 2.6-2.9 years. Localised nodules of ectopic mineralisation external to and within the intervertebral disc were regularly observed in early-phase DISH.

CONCLUSIONS

This is the first characterisation of spatiotemporal features across all phases of DISH, indicating that progression of DISH is characterised by distinct features at different phases along the disease continuum. Localised nodules of mineralisation in the spinal ligaments and within the intervertebral discs coincident with early phases of the disease may be a key factor in the pathogenesis of DISH.

Not All Osteophytes Are Located on the Right Side of the Vertebrae in Diffuse Idiopathic Skeletal Hyperostosis: A Quantitative Analysis in Relation to the Position of Aorta

OBJECTIVE

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by osteophytes in the anterior vertebrae, and the presence of aorta may have an impact on their formation. However, the anatomical positional relationship between the aorta and osteophytes in patients with DISH remains controversial. This study aimed to evaluate the position of osteophytes in relation to aorta in DISH, and the influence of aortic pulsation on the formation of osteophytes from the perspective of morphology.

METHODS

We conducted a retrospective review of 101 patients diagnosed with DISH and symptomatic lumbar spinal stenosis between June 2018 and December 2021. A total of 637 segments with heterotopic ossification in DISH were used for quantitative measurements on CT scans. The Cartesian coordinate system was built up on the axial CT scans to reflect the relative position between aorta and osteophytes. Osteophytes were divided into adjacent aorta group (AD group) and non-adjacent aorta group (N-AD group). In terms of the morphology, osteophytes in the AD group were further divided into convex, flat, and concave types. The relative position between aorta and osteophytes, and the aorta-osteophyte distance and morphology of osteophytes were compared. Univariate analysis of variance was performed for multiple groups, and two independent-samples t-tests were used for two groups.

RESULTS

From T5 to L4, aorta gradually descended from left side to middle of vertebrae, and osteophytes gradually shifted from right side of vertebrae (T5-T10) to bilateral sides (T11-L4). Of 637 osteophytes in DISH, 60.1% (383/637) were in AD group, including convex type 0.6% (4/637), flat type 34.7% (221/637), and concave type 24.8% (158/637). The N-AD group accounted for 39.9% (254/637). Flat osteophytes were concentrated in T5-T12, while concave osteophytes in T11-L4. Overall, the aorta-osteophyte distance of concave type was significantly smaller than that of flat type.

CONCLUSION

Osteophytes are not always located on the right side of vertebrae, but move with the position of the descending aorta. Furthermore, the morphology of osteophytes varies by vertebral segment in DISH, which is related to aorta descending anteriorly in the spine.

Negative Effects of Diffuse Idiopathic Skeletal Hyperostosis on Bone Fusion after Transforaminal Lumbar Interbody Fusion

STUDY DESIGN

This study adopted a retrospective cohort study design.

PURPOSE

This study aimed to clarify the influence of diffuse idiopathic skeletal hyperostosis (DISH) on bone fusion after transforaminal lumbar interbody fusion (TLIF).

OVERVIEW OF LITERATURE

The negative effects of DISH on lumbar degenerative diseases have been reported, and DISH may be involved in the onset and severity of lumbar spinal canal stenosis. Patients with DISH have significantly more reoperations after posterior lumbar fusion, including TLIF. However, the effects of DISH on bone fusion after TLIF have not been reported.

METHODS

The medical records of patients with intervertebral TLIF from 2012 to 2018 were retrospectively examined. The patients were divided into those with fusion and those with pseudoarthrosis, and the following data were compared: age, sex, DISH, diabetes mellitus, smoking, drinking, albumin levels, body mass index ≥30 kg/m2, and L5/S fixation. Statistical analyses were performed using regression models.

RESULTS

In this study, 180 patients (78.6%) had fusion and 49 patients (21.4%) had pseudoarthrosis. The number of patients with DISH was significantly higher in the pseudoarthrosis group than in the fusion group (36.7% and 21.7%, respectively; univariate p=0.031, multivariate p =0.019). No significant differences in age, sex, diabetes mellitus, smoking, drinking, albumin levels, body mass index ≥30 kg/m2, and L5/S fixation were observed between the two groups. The risk factors for bone fusion were statistically analyzed in 57 patients with DISH. DISH with a caudal end below Th11 was an independent risk factor for pseudoarthrosis (univariate p=0.011, multivariate p=0.033).

CONCLUSIONS

DISH is an independent risk factor for pseudoarthrosis after one intervertebral TLIF, and DISH with a caudal end below Th11 is associated with a higher risk of pseudoarthrosis than DISH without a caudal end below Th11.

How does diffuse idiopathic skeletal hyperostosis affect the sagittal spinopelvic alignment in lumbar spinal stenosis patients?

OBJECTIVE

To compare the differences of spinopelvic morphology among patients with DISH, patients without DISH and normal elderly and to assess the impact of ossification extent on sagittal alignment.

METHODS

Patients with and without DISH aged > 50 years who required surgery because of lumbar spinal stenosis were enrolled in this cohort(DISH and Non-DISH groups). Also, we collected age-matched normal old outpatients as the control group(Normal group). According to ossification extent, DISH group were divided into two subgroups(T-DISH and L-DISH subgroups). Spinopelvic parameters were measured. Distribution differences of Roussouly classification were analyzed between DISH and Non-DISH group, T-DISH and L-DISH subgroup, respectively. Additionally, distribution difference of kyphotic apex vertebrae between T-DISH and L-DISH subgroup was also investigated.

RESULTS

A total of 429 patients (300 males and 129 females) were enrolled in our study, with a mean age of 64.1 ± 5.8 years. Compared to the Normal group, DISH and Non-DISH groups both had significantly higher CSVA, PT, OH, SVA, TPA and lower LL, SS, C7 Tilt, SSA, SPA. Compared to Non-DISH group, DISH group, regardless of ossification extent, had significantly higher T1 slope, CSVA, TK and SVA. Besides, T-DISH subgroup showed significant higher LL, PI, SS and SSA than L-DISH subgroup. There were significant differences of Roussouly classification distribution between T-DISH and L-DISH subgroup. In terms of kyphotic apex location, compared to relatively higher locations in T-DISH subgroup, L-DISH subgroup had apical locations predominantly in the lower thoracic.

CONCLUSION

Sagittal spinopelvic alignment is influenced by the presence of DISH and the extent of ossification. Patients with L-DISH have not only increased thoracic kyphosis and forward trunk, but also insufficient lumbar lordosis.

Imaging Features of Early Diffuse Idiopathic Skeletal Hyperostosis (pre-DISH): Analysis of Progression of Ligament Ossification over 5 Years by Computed Tomography

Introduction

Some patients who have not been diagnosed with diffuse idiopathic skeletal hyperostosis (DISH) (patients in the preclinical stage of DISH [pre-DISH]) may develop DISH in the future. However, there are currently no clearly defined diagnostic criteria for pre-DISH. This study aims to define pre-DISH by analyzing the change in the ossification extent in each intervertebral space in the thoracic and lumbar spines over time using computed tomography (CT).

Methods

Of the patients who underwent CT of the thoracic to pelvic region at least twice from 2009 to 2018, 188 who underwent CT at an interval of 5 years to 5 years and 2 months were enrolled. The prevalence of DISH during the first and second CT scans was investigated. The pre-DISH feature was defined, and the prevalence of pre-DISH on the first CT and the change after 5 years in patients with pre-DISH was investigated.

Results

Of the 188 patients, 37 (19.7%) and 48 (25.5%) were diagnosed with DISH on the first and second CT scans, respectively. Pre-DISH was defined as the ossification characterized by the modified Mata score of three contiguous intervertebral spaces with a score of ≥2 points (222; 2 points, ligament ossification of half or more of the intervertebral disc height but incomplete fusion), and 52 patients were diagnosed with pre-DISH. Of the 52 patients with a score of ≥(222), 11 (21.2%) were diagnosed with DISH 5 years later.

Conclusions

Patients who have three contiguous intervertebral spaces with a modified Mata score of 2 or 3 points should be considered pre-DISH.

Cement-augmented pedicle screw for thoracolumbar degenerative diseases with osteoporosis: a systematic review and meta-analysis

BACKGROUND

Cement-augmentation pedicle screws have been widely used in spinal internal fixation surgery combined with osteoporosis in recent years, which can significantly improve the fixation strength, but compared with conventional methods, whether it has more advantages is still inconclusive of evidencebased medicine. To systematically evaluate the efficacy and safety of cement-augmented pedicle screw in the treatment of thoracolumbar degenerative diseases with osteoporosis.

METHODS

We searched PubMed, Embase, and Cochrane Library for studies published from the establishment of the database up until June 2023. We included studies that concerning the cement-augmented pedicle screw and the traditional pedicle screw placement for thoracolumbar degenerative diseases with osteoporosis. We excluded repeated publication, researches without full text, incomplete information or inability to conduct data extraction and animal experiments, case report, reviews and systematic reviews. STATA 15.1 software was used to analyze the data.

RESULTS

A total of 12 studies were included in this meta-analysis. The sample size of patients were totally 881, of which, 492 patients in cement-augmented screw group and 389 patients in conventional screw group. Meta-analysis results showed that Japanese Orthopaedic Association (JOA) score (WMD = 1.69, 95% CI 1.15 to 2.22), intervertebral space height (WMD = 1.66, 95% CI 1.03 to 2.29) and post-operation fusion rate (OR = 2.80, 95% CI 1.49 to 5.25) were higher in the cement-augmented screw group than those in the conventional screw group. Operation time was longer in the cement-augmented screw group than that in the conventional screw group (WMD = 15.47, 95% CI 1.25 to 29.70). Screw loosening rate was lower in the cement-augmented screw group than those in the conventional screw group (OR = 0.13, 95% CI 0.07 to 0.22). However, hospitalization time, intraoperative blood loss and Visual analog scale (VAS) score were not significantly different between the two groups (P > 0.05).

CONCLUSION

Compared with conventional pedicle screw placement, cement-augmented pedicle screw is more effective in the treatment of osteoporotic thoracolumbar degenerative disease by improving fusion rate and interbody height, reducing the incidence of screw loosening, and elevating long-term efficacy.

The Effect of Posterior Lumbar Interbody Fusion in Lumbar Spine Stenosis with Diffuse Idiopathic Skeletal Hyperostosis: A Finite Element Analysis

OBJECTIVE

Lumbar spinal canal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH) can require revision surgery because of the intervertebral instability after decompression. However, there is a lack of mechanical analyses for decompression procedures for LSS with DISH.

METHODS

This study used a validated, three-dimensional finite element model of an L1-L5 lumbar spine, L1-L4 DISH, pelvis, and femurs to compare the biomechanical parameters (range of motion [ROM], intervertebral disc, hip joint, and instrumentation stresses) with an L5-sacrum (L5-S) and L4-S posterior lumbar interbody fusion (PLIF). A pure moment with a compressive follower load was applied to these models.

RESULTS

ROM of L5-S and L4-S PLIF models decreased by more than 50% at L4-L5, respectively, and decreased by more than 15% at L1-S compared with the DISH model in all motions. The L4-L5 nucleus stress of the L5-S PLIF increased by more than 14% compared with the DISH model. In all motions, the hip stress of DISH, L5-S, and L4-S PLIF had very small differences. The sacroiliac joint stress of L5-S and L4-S PLIF models decreased by more than 15% compared with the DISH model. The stress values of the screws and rods in the L4-S PLIF model was higher than in the L5-S PLIF model.

CONCLUSIONS

The concentration of stress because of DISH may influence adjacent segment disease on the nonunited segment of PLIF. A shorter-level lumbar interbody fixation is recommended to preserve ROM; however, it should be used with caution because it could provoke adjacent segment disease.

Thoracic spondylotic myelopathy in diffuse idiopathic skeletal hyperostosis: a comparative study

BACKGROUND

To explore the characteristics and clinical management of thoracic spinal stenosis with diffuse idiopathic skeletal hyperostosis (DISH).

METHODS

The patients diagnosed with thoracic spondylotic myelopathy who underwent spinal decompression and fusion surgery in a single center between 2012 and 2020 were retrospectively analyzed. All the patients were followed up for at least 2 years. Patients were classified into DISH and non-DISH groups. Demographic, radiographic and clinical parameters were compared between the two groups.

RESULTS

A total of 100 thoracic spondylotic myelopathy patients were included in the study. 22 patients were diagnosed with DISH. The proportion of male patients in the DISH group was higher, and the average BMI was larger. The incidence of upper thoracic vertebrae with ossification of posterior longitudinal ligament (OPLL) (P < 0.05) and lumbar spine with ossification of ligamentum flavum (OLF) was higher (P < 0.05) in DISH the group. The proportion of patients received staged surgery is higher in the DISH group (P < 0.1). There were no significant differences between the two groups in the amount of surgical bleeding, the ratio of cerebrospinal fluid leakage, the time duration of drainage tube placement and the JOA scores.

CONCLUSION

Thoracic spinal stenosis with DISH occurred more in male patients with larger BMI. The posterior decompression and fusion surgery could achieve comparable satisfying clinical outcomes between DISH and non-DISH patients. More proportion of patients received staged surgery in the DISH group; the underline mechanism may be DISH caused more OPLL in the upper thoracic spine and more OLF in the lumbar spine because of mechanical stress.

A Scoring System for Anterior Longitudinal Ligament Ossification of the Lumbar Spine in Diffuse Idiopathic Skeletal Hyperostosis: Relationship Between the Extent of Ligament Ossification and the Range of Motion

STUDY DESIGN

Retrospective observational study.

OBJECTIVE

To investigate the relationship between the extent of ligament ossification and the range of motion (ROM) of the lumbar spine and develop a new scoring system.

METHODS

Forty-three patients (30 men and 13 women) with lumbar spinal canal stenosis who underwent decompression from January to December 2018. Ligament ossification at L1/2 to L5/S was assessed on plain X-ray (Xp) and computed tomography (CT) using a modified Mata scoring system (0 point: no ossification, 1 point: ossification of less than half of the intervertebral disc height, 2 points: ossification of half or more of the intervertebral disc height, 3 points: complete bridging), and the intra-rater and inter-rater reliability of the scoring was assessed. The relationship of the scores with postoperative lumbar ROM was investigated.

RESULT

Intra-rater reliability was high (Cronbach's α was 0.74 for L5/S on Xp but 0.8 or above for other sections), as was inter-rater reliability (Cronbach's α was 0.8 or above for all the segments). ROM significantly decreased as the score increased (scores 1 to 2, and 2 to 3). A significant moderate negative correlation was found between the sum of the scores at L1/2-L5/S and the ROM at L1-S (ρ = - 0.4493, P = 0.025).

CONCLUSION

Our scoring system reflects lumbar mobility and is reproducible. It is effective for assessing DISH in fractures and spinal conditions, and monitoring effects on treatment outcomes and changes over time.

Less-invasive decompression procedures can reduce risk of reoperation for lumbar spinal stenosis with diffuse idiopathic skeletal hyperostosis extended to the lumbar segment: analysis of two retrospective cohorts

PURPOSE

Clinical outcomes after decompression procedures are reportedly worse for lumbar spinal stenosis (LSS) with diffuse idiopathic skeletal hyperostosis (DISH), especially DISH extended to the lumbar segment (L-DISH). However, no studies have compared the effect of less-invasive surgery versus conventional decompression techniques for LSS with DISH. The purpose of this study was to compare the long-term risk of reoperation after decompression surgery focusing on LSS with L-DISH.

METHODS

This study compared open procedure cohort (open conventional fenestration) and less-invasive procedure cohort (bilateral decompression via a unilateral approach) with ≥ 5 years of follow-up. After stratified analysis by L-DISH, patients with L-DISH were propensity score-matched by age and sex.

RESULTS

There were 57 patients with L-DISH among 489 patients in the open procedure cohort and 41 patients with L-DISH among 297 patients in the less-invasive procedure cohort. The reoperation rates in L-DISH were higher in the open than less-invasive procedure cohort for overall reoperations (25% and 7%, p = 0.026) and reoperations at index levels (18% and 5%, p = 0.059). Propensity score-matched analysis in L-DISH demonstrated that open procedures were significantly associated with increased overall reoperations (hazard ratio [HR], 6.18; 95% confidence interval [CI], 1.37-27.93) and reoperations at index levels (HR, 4.80; 95% CI, 1.04-22.23); there was no difference in reoperation at other lumbar levels.

CONCLUSIONS

Less-invasive procedures had a lower risk of reoperation, especially at index levels for LSS with L-DISH. Preserving midline-lumbar posterior elements could be desirable as a decompression procedure for LSS with L-DISH.

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.

Is spinal sagittal alignment of diffuse idiopathic skeletal hyperostosis relevant to thoracolumbar pain? A controlled study

OBJECTIVES

The extension of diffuse idiopathic skeletal hyperostosis (DISH) from the low thoracic spine to the lumbar spine result in adjustment of spinal sagittal alignment in surgical patients. The aim of this study was to investigate changes in sagittal alignment and back pain in the thoracolumbar spine in nonsurgical DISH and control participants selected from a radiological database.

METHODS

Participants in the DISH and the control group were selected by searching for "DISH or degenerative changes in the thoracic spine" in the radiology database of Taizhou Hospital between 2018 and 2021 using Resnick and Niwayama's criteria. The subjects with spinal tumors, previous spinal surgery, vertebral fractures, inflammatory diseases, poor-quality radiographs, or loss of follow-up were excluded. Demographic and clinical characteristics were recorded retrospectively via the hospital information system and telephone follow-up. Segmental disc angles (SDAs), lumbar lordosis (LL), and bridge scores were analyzed using images of three-dimensional CT.

RESULTS

The final participants consisted of 51 individuals with DISH (DISH group) and 102 individuals without DISH (control group). Depending on the presence of thoracolumbar pain, the DISH group was divided into the DISH group with thoracolumbar pain (DISH+Pain) and the DISH group without thoracolumbar pain (DISH-Pain). The LL and SDAs of T11-T12 and T12-L1 were significantly greater in the DISH group than in the control group. In addition, the SDA of L1-L2 was significantly smaller in the DISH+Pain group than in the DISH-Pain group, whereas there was no significant difference in lumbar lordosis between the DISH+Pain group and the DISH-Pain group. The bridge scores in DISH+Pain group was larger in T10-T11 (p = 0.01) and L1-L2 (p < 0.01) spine segments than those in DISH-Pain group.

CONCLUSION

The extension of DISH from thoracic to lumbar spine may increase lumbar lordosis and SDAs in the thoracolumbar spine. The DISH patients with more bony bridging and small L1-L2 SDA may be more likely have thoracolumbar pain. Adjustment of sagittal alignment of the spine in the development of DISH may be of clinical importance.

Prognostic Factors and Optimal Surgical Management for Lumbar Spinal Canal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis

Lumbar spinal canal stenosis (LSS) and diffuse idiopathic skeletal hyperostosis (DISH) tend to develop in the elderly, resulting in an increased need for lumbar surgery. However, DISH may be a risk factor for poor clinical outcomes following lumbar decompression surgery, especially in patients with DISH extending to the lumbar segment (L-DISH). This study aimed to identify the prognostic factors of LSS with L-DISH and propose an optimal surgical management approach to improve clinical outcomes. Of 934 patients who underwent lumbar decompression surgery, 145 patients (15.5%) had L-DISH. In multivariate linear regression analysis of the JOA score improvement rate, the presence of vacuum phenomenon at affected segments (estimate: −15.14) and distance between the caudal end of L-DISH and decompressed/fused segments (estimate: 7.05) were independent prognostic factors. In logistic regression analysis of the surgical procedure with JOA improvement rate > 25% in L-DISH patients with both negative prognostic factors, the odds ratios of split laminotomy and short-segment fusion were 0.64 and 0.21, respectively, with conventional laminotomy as the reference. Therefore, to achieve better clinical outcomes in cases with decompression at the caudal end of L-DISH, decompression surgery without fusion sparing the osteoligamentous structures at midline should be considered as the standard surgery.

Life Expectancy Is Poor in Patients with Diffuse Idiopathic Skeletal Hyperostosis-Related Pyogenic Vertebral Osteomyelitis

Introduction

Pyogenic vertebral osteomyelitis (PVO) is an uncommon but life-threatening infectious disease. Diffuse idiopathic skeletal hyperostosis (DISH) is an age-related disorder and sometimes problematic in terms of spinal instability or high mortality, especially in cases of DISH-related fracture. Meanwhile, no reports have focused on the impact of DISH on the clinical outcomes after treatment for PVO. We hypothesized that PVO occurring at DISH-related segments might contribute to poor clinical results or high mortality rates. The purpose of this study was to investigate the impact of DISH on mortality after treatment for PVO in a retrospective cohort study.

Methods

This study involved patients who were hospitalized and treated for PVO at a single institution. DISH-related PVO was defined as PVO within a segment ossified by DISH or PVO at the neighboring intervertebral level of the segment ossified by DISH. Differences in mortality between patients with DISH-related and non-DISH-related PVO were investigated.

Results

This study included 55 patients. DISH-related PVO was observed in 13 patients. The mortality rate was significantly higher in patients with DISH-related PVO than in those with non-DISH-related PVO (62% and 23%, respectively; p=0.016). Propensity score-adjusted analysis showed that DISH-related PVO was an independent risk factor for mortality (adjusted hazard ratio, 2.79; p=0.034). The survival probability was significantly shorter in patients with DISH-related PVO than in those with non-DISH-related PVO (p=0.006). PVO in which the intravertebral body was the center of involvement was significantly more common in DISH-related PVO than in non-DISH-related PVO (38% and 5%, respectively; p=0.006).

Conclusions

DISH-related PVO was associated with a higher mortality rate and shorter life expectancy than non-DISH-related PVO. Similar to advanced age, PVO at the segment ossified by DISH should be recognized as a risk factor for mortality when choosing the optimal treatment strategy.

Risk Factors for Reoperation at Same Level after Decompression Surgery for Lumbar Spinal Stenosis in Patients with Diffuse Idiopathic Skeletal Hyperostosis Extended to the Lumbar Segments

Introduction

Diffuse idiopathic skeletal hyperostosis (DISH) extended to the lumbar segments (L-DISH) reportedly has adverse effects on the surgical outcomes of lumbar spinal stenosis (LSS). However, the risk factors in patients with L-DISH have not been clarified. The purpose of this study was to investigate the long-term risk factors for reoperation at the same level after decompression surgery alone for LSS in patients with L-DISH in a retrospective cohort study.

Methods

A postoperative postal survey was sent to 1,150 consecutive patients who underwent decompression surgery alone for LSS from 2002 to 2010. Among all respondents, patients who exhibited L-DISH by preoperative total spine X-ray were included in this study. We investigated risk factors for reoperation at the same level as the initial surgery among various demographic and radiological parameters, including the lumbar ossification condition and computed tomography (CT) or magnetic resonance imaging findings.

Results

A total of 57 patients were analyzed. Reoperations at the same level as that of the index surgery were performed in 10 patients (17.5%) and at 11 levels within a mean of 9.2 years. Cox proportional hazard regression analysis indicated that the independent risk factors for reoperation were a sagittal rotation angle ≥10° (adjusted hazard ratio: 5.17) and facet opening on CT (adjusted hazard ratio: 4.82). Neither sagittal translation nor the ossification condition in the lumbar segments affected reoperations.

Conclusions

A sagittal rotation angle ≥10° and facet opening on preoperative CT were risk factors for reoperation at the same level as that of the index surgery in patients with L-DISH. The surgical strategy should be carefully considered in those patients.

Diffuse Idiopathic Skeletal Hyperostosis of the Spine: Pathophysiology, Diagnosis, and Management

Diffuse idiopathic skeletal hyperostosis (DISH) is an ankylosing condition affecting up to 32.5% of the general cohort. Although often asymptomatic, affected individuals may present with back pain, stiffness, dysphagia, functional decline, and neurologic deficits. Radiographically, DISH is characterized by flowing ossifications along the anterior spine spanning ≥4 vertebral bodies. Although the etiology of DISH remains unknown, diabetes mellitus and other metabolic derangements are strongly associated with DISH. Importantly, spinal ankylosis in DISH predisposes patients to unstable spine fractures from low-energy trauma, and careful consideration must be taken in managing these patients. This article reviews the epidemiology and pathophysiology of DISH, and its clinical findings, diagnostic criteria, and management.

Negative impact of short-level posterior lumbar interbody fusion in patients with diffuse idiopathic skeletal hyperostosis extending to the lumbar segment

OBJECTIVE

The development of diffuse idiopathic skeletal hyperostosis (DISH) often requires further surgery after posterior decompression without fusion because of postoperative intervertebral instability. However, there is no information on whether fusion surgery is recommended for these patients as the standard surgery. The aim of this study was to review the clinical and imaging findings in lumbar spinal canal stenosis (LSS) patients with DISH affecting the lumbar segment (L-DISH) and to assess the indication for fusion surgery in patients with DISH.

METHODS

A total of 237 patients with LSS underwent 1- or 2-level posterior lumbar interbody fusion (PLIF) at the authors' hospital and had a minimum follow-up period of 2 years. Patients with L-DISH were classified as such (n = 27, 11.4%), whereas those without were classified as controls (non-L-DISH; n = 210, 88.6%). The success rates of short-level PLIF were compared in patients with and those without L-DISH. The rates of adjacent segment disease (ASD), pseudarthrosis, postoperative symptoms, and revision surgery were examined in the two groups.

RESULTS

L-DISH from L2 to L4 correlated significantly with early-onset ASD, pseudarthrosis, and the appearance of postsurgical symptoms, especially at a lower segment and one distance from the segment adjacent to L-DISH, which were associated with the worst clinical outcome. Significantly higher percentages of L-DISH patients developed ASD and pseudarthrosis than those in the non-L-DISH group (40.7% vs 4.8% and 29.6% vs 2.4%, respectively). Of those patients with ASD and/or pseudarthrosis, 69.2% were symptomatic and 11.1% underwent revision surgery.

CONCLUSIONS

The results highlighted the negative impact of short-level PLIF surgery for patients with L-DISH. Increased mechanical stress below the fused segment was considered the reason for the poor clinical outcome.

Progression of Ossification of the Anterior Longitudinal Ligament Associated With Diffuse Idiopathic Skeletal Hyperostosis by Age: A Study of Computed Tomography Findings Over 5 Years

STUDY DESIGN

Observational study.

OBJECTIVE

To investigate whether the progression of anterior longitudinal ligament ossification varies by age among patients with diffuse idiopathic skeletal hyperostosis (DISH).

METHODS

Of the patients who underwent computed tomography (CT) of the thoracic to pelvic region at least twice from 2009 to 2018, 191 who underwent CT at an interval of 5 years and 0 months to 5 years and 2 months were enrolled (87 men and 104 women). Sex, age at the time of the first CT scan, the presence/absence of DISH, level of complete vertebral body fusion associated with DISH, and extent of ligament ossification using the modified Mata scoring system were investigated.

RESULTS

DISHs were detected in 53 (27.7%) of 191 patients. The score of ligament ossification increased over time in 35 (66%) of 53 patients; 93 intervertebral spaces were affected. The percentage of completely fused intervertebral spaces increased by 6.7% from 31.3% to 38.0% over time. The increase in score for all intervertebral spaces in individual patients was significantly greater in the ≤70 years old group (2.7 ± 2.8 points, n = 28) than in the ≥71 years old group (1.2 ± 1.4 points; n = 25; P = .028). The mean age of patients with a recorded score that increased by ≥1 point was 67.4 years and that of patients without any change in the score was 73.3 years (P = .036). Thus, patients with recorded changes in the score were younger.

CONCLUSION

During the approximately 5-year period, ossification progressed more in younger patients than in older patients.

Pathomechanism and prevention of further surgery after posterior decompression for lumbar spinal canal stenosis in patients with diffuse idiopathic skeletal hyperostosis

BACKGROUND CONTEXT

Diffuse idiopathic skeletal hyperostosis (DISH) is a risk factor for further surgery after posterior decompression without fusion for patients with lumbar spinal canal stenosis (LSS). However, a strategy to prevent revision surgery has not been described.

PURPOSE

The aim of this study was to review clinical and imaging findings in LSS patients with DISH extending to the lumbar segment and to propose countermeasures for prevention of revision surgery.

STUDY DESIGN

A retrospective study.

PATIENTS SAMPLE

A total of 613 consecutive patients with LSS underwent posterior decompression without fusion at our hospital and had a minimum follow-up period of 2 years. We defined patients with DISH bridging to the lumbar segment as L-DISH cases (group D, n=111), and those without as non-L-DISH cases (group N, n=502).

OUTCOME MEASURE

Demographic data including the rate of revision surgery, neurological examination using Japanese Orthopaedic Association score, radiological studies comprised plain lumbar radiography, CT, and high-resolution MRI were assessed.

METHODS

Clinical features and imaging findings were compared in patients with and without L-DISH. Revision surgery and surgical procedures (conventional laminotomy or lumbar spinous process-splitting [split] laminotomy) were examined in the two groups. No funding was received for this study.

RESULTS

L-DISH from L2 to L4 was a risk factor for disc degeneration such as a vacuum phenomenon and for further surgical treatment. The rate of revision surgery was higher in group D than in group N (9.0% vs. 4.0%, p=.026). There was no significant difference in this rate for patients in groups D and N who underwent conventional laminotomy; however, for those who underwent split laminotomy, the rate was significantly higher in group D (16.7% vs. 2.1%, p=.0006). Furthermore, the rate of revision surgery after split laminotomy at a lower segment adjacent to L-DISH was significantly higher than that after conventional laminotomy (37.5% vs. 7.7%, p=.037).

CONCLUSIONS

A negative impact of lumbar spinous process-splitting laminotomy was found, especially with decompression at a lower segment adjacent to L-DISH. In such cases, surgery sparing the osteoligamentous structures at midline, including the spinous process and supra- and interspinous ligaments, should be selected.

Diffuse idiopathic skeletal hyperostosis: A potential factor in the induction of thoracic spondylotic myelopathy

BACKGROUND

Thoracic spondylotic myelopathy (TSM) commonly occurs at the thoracolumbar junction, and mechanical stress is thought to be involved. In DISH, the anterior longitudinal ligament becomes ossified. Although DISH is suspected to be involved in TSM pathology, reports are limited. Aim of this study is to investigate the association between (TSM) and diffuse idiopathic skeletal hyperostosis (DISH).

METHODS

Fifty-one patients with thoracic myelopathy underwent surgery between April 2008 and April 2017. Of these, 28 patients with TSM were included and examined. DISH was confirmed using computed tomography (CT). Subjects were divided into DISH and non-DISH sub-groups according to CT findings, and the DISH coexistence rate was calculated. Groups were analyzed for sex, age, postoperative Japanese Orthopedic Association (JOA) score, and reoperation status. In the DISH group, the positional relationship between the affected vertebral level of TSM and consecutive vertebral bone bridges was analyzed. Patients without spinal disease matched for sex and age were enrolled as controls (N = 56). The DISH coexistence rate was compared and analyzed between groups.

RESULTS

Mean age at surgery was 67.8 years (43-82 years; 22 men, 6 women). DISH was detected in 17 of 28 patients (60.7%; 15 men, 2 women). No significant difference in the improvement rate of JOA score was observed between groups. TSM occurred at: lower border of a consecutive vertebral bone bridge, N = 4; upper border, N = 3; between consecutive vertebral bone bridges, N = 5; one vertebral body away from a consecutive vertebral bone bridge, N = 5. No patient had TSM occurring within a consecutive vertebral bone bridge. The DISH coexistence rate in patients with TSM (60.7%) was significantly higher than that in controls (20/56, 35.7%) (p = 0.03).

CONCLUSION

Mechanical stress caused by consecutive vertebral bone bridges due to DISH may be involved in TSM pathogenesis. Therefore, in DISH patients, attention needs to be paid to TSM onset.

Diagnostic Screening for Lumbar Spinal Stenosis

Purpose

To develop a self-administered diagnostic screening questionnaire for lumbar spinal stenosis (LSS) consisting of items with high content validity and to investigate the diagnostic value of the questionnaire and the items.

Patients and Methods

A self-reported diagnostic LSS screening questionnaire was developed based on items from the existing literature describing key symptoms of LSS. The screening questionnaire (index test) was to be tested in a cohort of patients with persistent lumbar and/or leg pain recruited from a Danish publicly funded outpatient secondary care spine clinic with clinicians performing the reference test. However, to avoid unnecessary collection of data if the screening questionnaire proved to be of limited value, a case-control design was incorporated into the cohort design including an interim analysis. Additional cases for the case-control study were recruited at two Danish publicly funded spine surgery departments. Prevalence, sensitivity, specificity and diagnostic odds ratio (OR) were calculated for each individual item, and AUC (area under the curve) was calculated to examine the performance of the full questionnaire.

Results

A 13-item Danish questionnaire was developed and tested in 153 cases and 230 controls. The interim analysis was not in favour of continuing the cohort study, and therefore, only results from the case-control study are reported. There was a positive association for all items except the presence of back pain. However, the association was only moderate with ORs up to 3.3. When testing the performance of the whole questionnaire, an AUC of 0.72 was reached with a specificity of 20% for a fixed sensitivity of 95%.

Conclusion

The items were associated with LSS and therefore have some potential to identify LSS patients. However, the association was not strong enough to provide sufficient accuracy for a diagnostic tool. Additional dimensions of symptoms of LSS need identification to obtain a reliable questionnaire for screening purposes.

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.

Sacroiliac joint variation associated with diffuse idiopathic skeletal hyperostosis

Background

Diffuse idiopathic skeletal hyperostosis (DISH) is characterized by the ossification of vertebral bodies and peripheral entheses. However, variations in sacroiliac (SI) joint change in patients with DISH have not been fully clarified. The purpose of this study was to evaluate SI joint variation in patients with DISH in comparison with a non-DISH population.

Methods

A total of 342 SI joints in 171 patients (DISH+, n = 86; DISH-, n = 85) who had undergone lumbar spine surgery were analyzed by computed tomography examination. SI joint variations were classified into four types: Type 1, normal or tiny peripheral bone irregularity; Type 2, subchondral bone sclerosis and osteophytes formation; Type 3, vacuum phenomenon; and Type 4, bridging osteophyte and bony fusion. The type of bridging osteophyte in SI joints and the prevalence of ossification in each spinal segment from C1 to SI joint were also examined.

Results

The most common SI joint variation in the DISH+ group was bony fusion (Type 4), with 71.6% exhibiting anterior paraarticular bridging. On the other hand, SI joint vacuum phenomenon (Type 3) was the most frequent change (57.1%) in the DISH- group. The middle to lower thoracic spine and SI joints were highly affected in DISH and caused bony ankylosis.

Conclusions

Anterior paraarticular bridging was the most common type of SI joint change in patients with DISH who underwent lumbar spine surgery. The present results regarding variations of SI joint changes in DISH should help understand the etiology of DISH.

Outcomes of lumbar decompression surgery in patients with diffuse idiopathic skeletal hyperostosis (DISH)

BACKGROUND

Only a few studies have described the effect of diffuse idiopathic skeletal hyperostosis (DISH) on the clinical results after lumbar surgery. The aim of the study is to clarify the associations between DISH and the clinical results after lumbar decompression surgery.

METHODS

The outcomes of 328 consecutive patients who underwent primary lumbar decompression surgery for treatment of lumbar canal stenosis with or without grade I spondylolisthesis were analysed retrospectively. The major outcome measures were surgery-free survival and the need for further surgery because of same-segment disease (SSD) and/or adjacent-segment disease (ASD).

RESULTS

Of the 328 patients, 69 (60 men and nine women) were diagnosed with DISH. The Japanese Orthopaedic Association score before and at 1 year after the surgery did not differ significantly between patients with and without DISH. However, the rate of revision surgery in the follow-up period was significantly higher in patients with DISH than in those without (19% vs 6.9%, p = 0.0050). Cox proportional-hazards modelling revealed that DISH and sex (female) were independent risk factors for the need for revision surgery after decompression surgery for degenerative lumbar spine. The rate of revision surgery was higher in the sub-group of DISH with ossification extended to L2 or more than that for those with the ossification extended to L1 (26% vs 8%, p = 0.11), but the difference did not reach statistical significance.

CONCLUSIONS

DISH is a risk factor for revision surgery after decompression surgery for degenerative lumbar spine because of SSD and/or ASD.

[Differential diagnosis of axial spondyloarthritis-axSpA mimics]

The classification of axial spondyloarthritis (axSpA) comprises the classical ankylosing spondylitis (AS), which is characterized by already existing structural changes in the sacroiliac joints, and the so-called non-radiographic axSpA (nr-axSpA), in which by definition such changes are not present. This distinction is based on the ASAS classification criteria for axSpA, which are however not suitable for a diagnosis. According to the current classification, spondyloarthritis (SpA) includes axSpA, which can be associated with psoriasis and/or chronic inflammatory bowel diseases (CED), such as Crohn's disease and ulcerative colitis, and peripheral SpA, which is further divided into SpA associated with psoriasis, partially synonymous with psoriatic arthritis (PsA), reactive SpA, partially synonymous with reactive arthritis (ReA) and SpA associated with CED, partially synonymous with arthritis associated with CED (e.g. Crohn's disease, ulcerative colitis) and peripheral undifferentiated SpA, which by definition is not associated with any of the above. In this article only the most important differential diagnoses are discussed, i. e. diffuse idiopathic skeletal hyperostosis (DISH), fractures and infections in the axial skeleton. In addition, the frequency of certain musculoskeletal findings in the normal population examined by magnetic resonance imaging (MRI) are also discussed.