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

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.

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.

Impact of Diffuse Idiopathic Skeletal Hyperostosis on Clinico-Radiological Profiles and Prognosis for Thoracic Ossification of Ligamentum Flavum-Myelopathy: A Propensity-Matched Monocentric Analysis

Background: Diffuse idiopathic skeletal hyperostosis (DISH) has been evaluated as a potential risk factor of poor surgical outcomes for lumbar spinal stenosis, whereas the influence of DISH on neuroimaging characteristics and postoperative prognosis of patients with thoracic myelopathy has not been established. Therefore, this study aimed to shed light on this issue. Methods: A monocentric study enrolled 167 eligible patients with thoracic ossification of ligamentum flavum (TOLF), who were followed up for at least 2 years. Clinico-radiological parameters and surgical outcomes were compared between the DISH+ and DISH− groups before and after propensity matching. Subgroup analysis was conducted to compare the functional outcomes between mild DISH (M-DISH) and moderately severe DISH (MS-DISH) groups. Results: Fifty-eight patients were diagnosed as DISH, and its prevalence was 34.7%. Patients with DISH presented with older age, more males, taller stature, heavier weight, more commonly diffuse-type TOLF (p < 0.05). The DISH group showed significantly worse recovery rate (RR) at the final follow-up before and after propensity matching (p < 0.01), and slightly lower preoperative VAS, higher postoperative VAS and lower VAS reduction, despite not reaching the significant differences. Subgroup analysis demonstrated that the M-DISH group was associated with the lower mJOA score (p = 0.01) and RR at the final follow-up (p = 0.001), and tended to present higher preoperative VAS than the MS-DISH group. Conclusions: DISH has a significant predisposition to the elderly males with diffuse-type TOLF. Although the presence of M-DISH might bring about a suboptimal surgical outcome, both DISH and non-DISH patients experienced good neurological function improvements and pain relief through thoracic posterior decompression.

Can Diffuse Idiopathic Skeletal Hyperostosis Be Diagnosed by Plain Lumbar Spine X-Ray Findings Alone?

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

To determine whether diffuse idiopathic skeletal hyperostosis (DISH) can be diagnosed based on anterior longitudinal ligamental ossification in the lumbar spine using plain lumbar spine X-ray images.

METHODS

This study included 100 patients (59 men and 41 women; mean age, 64.8 ± 13.8 years; range, 27-89 years) who underwent computed tomography (CT) of the chest to the pelvis in our hospital and plain lumbar spine radiography within 6 months before and after CT scanning. DISH was diagnosed based on the thoracolumbar spine CT findings using Resnick's diagnostic criteria. The patients were grouped according to DISH diagnosis into the DISH (+) and DISH (-) groups. On the frontal and lateral lumbar spine X-ray images, each spinal level from Th11/12 to L5/S was scored based on the Mata scoring system. The distribution of the Mata scores was compared between the 2 groups.

RESULTS

Forty (40%) patients were diagnosed with DISH based on the CT findings. A cutoff value ≥8 provided a sensitivity of 75% and specificity of 100% for diagnosing DISH, thus, indicating the validity of the cutoff value. In the DISH (-) group, no patient had ≥3 consecutive spinal levels with a Mata score ≥2, suggesting that DISH can be diagnosed on the basis of at least 3 consecutive spinal levels with a Mata score ≥2.

CONCLUSION

On lumbar spine X-ray images of the T11/12 to L5/S levels, a Mata score ≥2 for at least 3 consecutive levels or a total score ≥8 strongly indicates the presence of DISH.

Diffuse Idiopathic Skeletal Hyperostosis Combined with Thoracic Spinal Stenosis Treated by Endoscopic Surgery: A Case Report

CASE

A 48-year-old man presented to our facility with debilitating motor and sensory symptoms due to advanced T10-11 thoracic spinal stenosis secondary to diffuse idiopathic skeletal hyperostosis (DISH). The patient's condition was addressed with endoscopic spine surgery through a yet-to-be-reported interlaminar approach, and at the 12-month follow-up, his neurologic function was significantly improved.

CONCLUSION

Select patients with symptomatic thoracic spinal stenosis secondary to DISH can be effectively managed with endoscopic spine surgery through an interlaminar approach by clinicians with extensive endoscopic spine experience.

Thoracic spondylotic myelopathy presumably caused by diffuse idiopathic skeletal hyperostosis in a patient who underwent decompression and percutaneous pedicle screw fixation

A 74-year-old man developed bilateral lower limb spastic paresis. He was diagnosed with thoracic spondylotic myelopathy presumably caused by mechanical stress that was generated in the intervertebral space (T1-T2) between a vertebral bone bridge (C5-T1) due to diffuse idiopathic skeletal hyperostosis after anterior fixation of the lower cervical spine and a vertebral bone bridge (T2-T7) due to diffuse idiopathic skeletal hyperostosis in the upper thoracic spine. Treatment included posterior decompression (T1-T2 laminectomy) and percutaneous pedicle screw fixation at the C7-T4 level. Six months after surgery, the patient could walk with a cane, and the vertebral bodies T1-T2 were bridged without bone grafting. For thoracic spondylotic myelopathy associated with diffuse idiopathic skeletal hyperostosis, decompression and percutaneous pedicle screw fixation are effective therapies.

One-stage posterior surgery with intraoperative ultrasound assistance for thoracic myelopathy with simultaneous ossification of the posterior longitudinal ligament and ligamentum flavum at the same segment: a minimum 5-year follow-up study

BACKGROUND CONTEXT

Ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF) are not uncommon independent causes of thoracic myelopathy (TM); however, concomitant OPLL and OLF at the same segment is rare. The ideal surgical strategy remains controversial, and it is difficult for surgeons to balance sufficient neural decompression while simultaneously reducing the occurrence of postoperative neurological defect after circumferential decompression (CD). Aiming to solve this dilemma, we investigated a CD-based surgery using intraoperative ultrasound (IOU) assistance to evaluate spinal decompression sufficiency.

PURPOSE

The aims of this study are to evaluate the surgical outcomes and identify prognostic factors of one-stage posterior surgery with IOU assistance in patients with concomitant OPLL and OLF.

STUDY DESIGN/SETTING

Retrospective study of a single-center TM database with long-term follow-up.

PATIENT SAMPLE

Twenty-four patients with TM and concomitant OPLL and OLF.

OUTCOME MEASURES

Japanese Orthopaedic Association (JOA) score system for TM, recovery rate (RR), complication rate.

METHODS

Twenty-four patients' data were retrospectively reviewed. All patients initially underwent en bloc excisions of posterior spinal canal elements, and IOU was then used to evaluate spinal decompression sufficiency. If any compression of OPLL was confirmed in IOU, further CD procedure was performed. The JOA score was used to evaluate health-related quality of life. RR was calculated using the Hirabayashi formula. A RR ≥50% was considered favorable, and a RR <50% was considered unfavorable. The paired t test was performed to statistically compare the preoperative and postoperative JOA scores. The chi-squared test, rank sum test, and logistic regression analyses were performed to find variants associated with unfavorable surgical outcomes The prognostic factors were analyzed by Spearman correlation and Pearson correlation analyses.

RESULTS

The invasive CD procedure were avoided in 9 of 28 segments were avoided, with a mean blood loss of 1,458 mL. Seventeen patients experienced cerebrospinal fluid leakage, and 5 experienced immediate postoperative paralysis. The mean JOA score improved from 4.25±2.2 (preoperative) to 8.16±1.9 (final follow-up). The mean RR was 57.7%±29.4%. There was a significant difference (p<.01) between the preoperative and final follow-up JOA score. A comparison between the favorable and the unfavorable groups showed no significant differences in the evaluated factors, but the considerable blood loss was a significant risk factor for poor RR (p=.036, b=-0.43).

CONCLUSIONS

One-stage CD-based surgery via a posterior approach with IOU assistance for the treatment of concomitant OPLL and OLF led to significant functional improvement in the majority of patients. Under the premise of sufficient decompression, the postoperative paralysis rate reduced compared to that in previous studies. However, there were still high cerebral spinal fluid leakage rates. Considerable blood loss is a risk factor for poor RR.