Prevalence of Cervical and Thoracic Spinal Disease: A Systematic Review

1. Prevalence of Degenerative Cervical Spondylotic Myelopathy (Table 1)

Table 1.

Prevalence of cervical spondylotic myelopathy in the reviewed studies

In 1997, Moore and Blumhardt [9] reported a prospective study of non-traumatic spastic paraparesis and tetraparesis in 585 patients. In this study, they found cervical spondylotic myelopathy to be the most common diagnosis (23.6%) in 585 patients admitted to a United Kingdom hospital with tetraparesis or paraparesis.

In 2007, Lee et al. [10] reported anatomic study in cadavers of prevalence of cervical spine stenosis, they estimated that cervical stenosis was present in 4.9% of the adult population, 6.8% of the population fifty years of age or older, and 9% of the population seventy years of age or older.

In 2012, Bajwa et al. [11] reported anatomical descriptive analysis of congenital cervical spinal stenosis. In this article, it has been estimated that congenital spinal canal stenosis is present in approximately 250,000 to 500,000 people in the United States, of which 20% to 25% are cervical.

In 2014, Miyazaki et al. [12] reported a retrospective study of analysis of the prevalence and distribution of cervical and thoracic compressive lesions of the spinal cord in lumbar degenerative disease. According to this study, in 145 cervical and thoracic spine, compressive lesions from the anterior parts were observed in 34 cases (23.4%). Compressive lesions from the anterior and posterior parts were observed in 34 cases (23.4%). Lesions of ossification of the ligamentum flavum were observed in 45 cases (31.0%). Lesions of ossification of the posterior longitudinal ligament were observed in 15 cases (10.3%).

In 2014, Schairer et al. [13] reported retrospective cohort study of prevalence of cervical spondylosis in patients with adult thoracolumbar spinal deformity. In this study, a total of 47,560 patients were included in this study. Cervical spondylosis occurred in 13.1% overall, but was found in 31.0% of patients with thoracolumbar spinal deformity. Similarly, thoracolumbar spinal deformity was found in 10.7% of patients overall, but was increased at 23.5% in patients with cervical spondylosis.

In 2014, New et al. [14] reported the review article of global maps of non-traumatic spinal cord injury epidemiology: towards a living data repository. In this article, the degenerative diseases of the spine make up 59% of nontraumatic spinal cord injury in Japan, 54% in the United States, 31% in Europe, 22% in Australia, and between 4% and 30% in Africa. In this same review, it was estimated that the regional incidence of nontraumatic spinal cord injury in North America, Europe, and Australia was 76, 26, and 6 per million, respectively, and that the prevalence is 1,120 per million in Canada and 2,310 per million in the Kashmir region.

In 2015, Boogaarts and Bartels [15] reported a review article of prevalence of cervical spondylotic myelopathy. In this study, surprisingly, an extensive search of the literature did not reveal exact data about the incidence or prevalence of cervical spondylotic myelopathy. The prevalence of surgically treated cervical spondylotic myelopathy was estimated as 1.6 per 100,000 inhabitants.

In 2015, Nouri et al. [16] reported a review article of degenerative cervical myelopathy: epidemiology, genetics, and pathogenesis. In this article, it can be estimated that the incidence and prevalence of nontraumatic spinal cord injury related to degenerative cervical myelopathy in the North American region is at a minimum of 41 and 605 per million, respectively.

In 2017, Nouri et al. [17] reviewed magnetic resonance (MR) images of 458 patients with degenerative cervical myelopathy (DCM) and found that cervical spondylosis was most frequent cause of degenerative cervical myelopathy with a frequency of 89.7%. Nearly 60% of spondylosis was accompanied by hypertrophy or enlargement of the ligamentum flavum (LF). Each of single-level discopathy, ossification of the posterior longitudinal ligament (OPLL), and spondylolisthesis had a prevalence with approximately 10%.

In 2018, Ko et al. [18] reported a prevalence of cervical foraminal stenosis (CFS) on computed tomography. In this study, among all 438 patients, left C5-6 stenosis was most common (24.66%), and the most severe stenosis of grade 2 was found in the left C5-6 (2.97%). The prevalence of stenosis at C4-5 was 10.50% on the right side and 13.47% on the left side; at C5-6, it was 13.47% on the right side and 24.66% on the left side; at C6-7, it was 10.96% on the right side and 12.10% on the left side. The prevalence of CFS was high in the following order: left C5-6, left C4-5 and right C5-6, and left C6-7. Overall, the incidence of CFS was greater on the left side than on the right side.

In 2020, Wada et al. [19] reported the prevalence of cervical canal stenosis in farmers. In female farmers, the rate of canal stenosis has already reached 50% among those in their 50s. The rates were over 50% in female non-farmers and males aged 60 and older in both groups. In men, the spinal canal diameter at the C4/5 level was smaller among farmers than non-farmers, and there were no significant differences at other levels. Findings of ossification of posterior longitudinal ligament existed in 5.8% of male and 3.9% of female farmers, and no significant difference in rate was found between farmers and non-farmers in both sexes.

In 2020, Naylor et al. [20] retrospectively reviewed high prevalence of cervical myelopathy in patients with idiopathic normal pressure hydrocephalus. In this study, fifty-two patients shunted for treatment of iNPH were included for analysis. 58% were male with a mean age of 75.2 years (SD 7.3 years). All patients presented with gait disturbances. 39/52 (75%) had cervical stenosis, and 9/52 (17.3%) had significant (grade 2–3) cervical stenosis with myelopathy and were subsequently treated with surgical decompression.

In 2020, Liao et al. [21] reported the overall prevalence of OPLL in the 7,210 DCM patients was 18.22%, including 19.73% in males and 15.65% in females, with a significant difference between the two groups. The prevalence of OPLL in diabetes mellitus (DM) and hypertensive patients was significantly higher than that in non-DM and normotensive patients (24.16% vs. 18.76% and 22.26% vs. 17.91%). Comparison by age and body mass index (BMI) showed that the prevalence of OPLL was the highest in the 70- to 79-year age group (21.91%) and obesity group (26.51%), respectively.

In 2021, Smith et al. [22] reported meta-analysis of the prevalence of asymptomatic and symptomatic spinal cord compression (SCC) on magnetic resonance (MR) imaging. The present search returned 1,506 publications. Following our exclusion criteria, 19 studies were included. Subgroup analysis of 3,786 individuals estimated the prevalence of asymptomatic SCC in a healthy population as 24.2% with a significantly higher prevalence of SCC in older populations compared with younger populations and American/European populations compared with Asian populations. A subgroup analysis of 1,202 individuals estimated the prevalence of DCM in a healthy population as 2.3%.

In 2022, Banerjee et al. [23] reported a review article of the prevalence of DCM-related pathologies on MR imaging. In this meta-analysis study, the search yielded a total of 1,098 studies of which 17 were included in this meta-analysis covering a total of 5,059 patients. According to this study, a prevalence of 0.4% for OPLL, 11.8% of enlargement of LF and 64.5% of degenerative multilevel disc pathology were found to be significantly lower in asymptomatic populations. On the other hand, symptomatic populations have a prevalence of 10.5% for OPLL, 56.8% for enlargement of LF and 89.7% for degenerative multilevel disc pathology.

In 2023, Grodzinski et al. [24] reported meta-analysis of most DCM remains undiagnosed, particularly amongst the elderly: modelling the prevalence of DCM in the United Kingdom. In this article, the mean prevalence of DCM across all age groups was 0.19%, with a peak prevalence of 0.42% at age 50–54 years. This contrasts with estimates from SCC data which suggest a mean prevalence of 2.22% and a peak prevalence of 4.16% at age >79 years.

2. The Prevalence of Ossification of Posterior Longitudinal Ligament (OPLL) (Table 2)

Table 2.

Prevalence of cervical ossification of the posterior longitudinal ligament in the reviewed studies

In 2012, the prevalence of OPLL has been extensively reported. The early incidence of OPLL based on lateral radiographs was 0.1% to 1.7% in Europe, 0.1% to 1.3% in the United States, 2.1% to 3.0% in Taiwan, 0.6% to 3.6% in South Korea, and 1.9% to 4.3% in Japan [25].

Sasaki et al. [26] utilized plain X-rays to investigate the prevalence and symptoms of OPLL in 1,291 Japanese general residents, and found that the prevalence of OPLL in symptomatic patients was apparently higher than that in asymptomatic participants (3.9% vs. 2.2%).

With the development of imaging technology and equipment for the spine assessment, the recent OPLL prevalence based on CT was 1.3% to 3.2% in the United States, 5.7% in South Korea, and 6.3% in Japan given that CT has a high sensitivity to OPLL as compared to radiography [27-29] (Figure 2).

Fig. 2

(A) Cervical reconstruction computed tomography (CT) scan shows a long strip of ossification posterior to the C2-C3 vertebral bodies and mixed configuration at C4-7. (B) Axial CT shows an ossified mass with a hole inside encroaching on the spinal canal. (C) Sagittal T2-weighted magnetic resonance imaging (MRI) shows bandlike low or no signal intensity of an ossified mass compressing the spinal cord at C2-7. (D) Axial T2- weighted MRI shows a huge ossified mass compressing the spinal cord.

Epstein [30] found that about 25% of patients treated surgically for cervical myelopathy exhibited ossification of the posterior longitudinal ligament.

In 2016, Nakashima et al. [31] studied 479 patients with symptomatic DCM based on AO spine cervical spondylotic myelopathy (CSM)-international study database, and found that the overall prevalence of OPLL in patients with DCM was 28.18% and 35.33% in the Asian and Pacific populations, 18.70% in North American populations, and 31.75% in European populations.

Liao et al. [21] reported a cross-sectional study of the prevalence of OPLL in patients with DCM: cervical spine 3D CT observations in 7,210 cases. In this article, the results showed that the prevalence rate of OPLL in patients with DCM was 18.22%, which is much higher than that in the general Asian population as reported in previous studies, indicating that OPLL commonly coexists with degenerative spondylosis in the cervical spine.

In 2016, Fujimori et al. [28] reported prevalence, concomitance, and distribution of ossification of the spinal ligaments: results of whole spine CT scans in 1,500 Japanese patients. In this study, the prevalence of spinal ligament ossifications was found to be 6.3% in cervical OPLL (8.3% in men and 3.4% in women), 23% in ossification of nuchal ligament (ONL) (33% in men and 8.8% in women), 1.6% in thoracic OPLL (1.4% in men and 2.0% in women), 12% in thoracic OLF (15% in men and 7.7% in women), 37% in thoracolumbar ossification of anterior longitudinal ligament (OALL) (45% in men and 26% in women), and 2% in diffuse idiopathic skeletal hyperostosis (DISH) (16% in men and 6.2% in women). Thirteen percent of patients with cervical OPLL had thoracic OPLL, 34% of cervical OPLL had thoracic OLF, 45% of cervical OPLL had ONL, and 36% of cervical OPLL had DISH. The most common level was C5 for cervical OPLL, T1/2 for thoracic OPLL, T11 for thoracic OLF, and T8/9 for OALL.

In 2022, Choi et al. [32] reported in 2020 prevalence, distribution, and concomitance of whole-spine OPLL and OLF in South Koreans. A total of 1,934 adults (1,645 men, 289 women) were included. The mean age was 48.05 years (range, 28–86 years). Among the 1,934 patients, 173 had OPLL (8.9%). The most commonly involved cervical vertebra levels arranged according to frequency were C4, C5, C3, and C6. OLF was observed in 125 patients (6.5%). The most commonly involved thoracic levels were T10, T11, and T5. The prevalence of OPLL and OLF was the highest in patients aged 60–69 years. Among the C-OPLL patients, 15.1% had T-OPLL, 5.0% had L-OPLL, and 25.8% had T-OLF.

In 2019, Liang et al. [33] reported epidemiology of ossification of the spinal ligaments and associated factors in the Chinese population: a cross-sectional study. The prevalence rate of cervical OPLL was 4.1%, thoracic OPLL 2.25%, lumbar OPLL 0.8%, thoracic OLF 37.65%, lumbar OLF 1.45%, ONL 31.5%, DISH 3.85%. The most commonly involved level was C5 for C-OPLL, T1 for T-OPLL, T10 for T-OLF, and T8/9 for OALL. 21% of subjects with C-OPLL had T-OPLL, 44% of C-OPLL had T-OLF, 38% of T-OPLL had C-OPLL, 53% of T-OPLL had T-OLF, 44% of L-OPLL had T-OPLL, and 56% of L-OPLL had T-OLF (Figure 3).

Fig. 3.

(A) Sagittal computed tomography (CT) scans demonstrating the local ossified ligamentum flavum extending on C4-5.(B) Axial CT scan at the level of C4-5 demonstrating significant posteromedial compression in the spinal canal. (C) Abnormally high T2 signal of the cervical cord opposite the C4-5 level, with the cervical cord being compressed between the right paracentral disc protrusion and abnormal bilateral symmetrical posterior extradural lesions with low signal on all pulse sequences. (D) Abnormally high T2 signal of the cervical cord opposite the C4-5 level, with the cervical cord being compressed between right paracentral disc protrusion and abnormal bilateral symmetrical posterior extradural lesions with low signal on all pulse sequences.

3. Prevalence of Thoracic Degenerative Spinal Disease (Table 3)

Table 3.

Prevalence of thoracic spondylotic spinal disease in the reviewed studies

In 1983, Kudo et al. [34] reported a long-term follow-up investigation of a fixed sample of ossification of thoracic ligamenta flava. In this article, review of 1,744 consecutive lateral chest radiographs identified ligamentum flavum ossification (LFO) in 6.2% of males and 4.8% of females. LFO occurred mainly at the intervertebral segments from T9-T10 through T12-L1. Most prevalent was the hook-shaped LFO, protruding inferiorly from the inferior facets into the projections of the intervertebral foramina. Though LFO can cause severe neurologic symptoms, none of the affected persons in this study reported such symptoms. LFO was first visualized radiographically when the subjects were 20–40 years old, and it may be a physiologic condition.

In 2008, Niemeläinen et al. [35] reported a cross-sectional study of thoracic magnetic resonance image (MRI) findings. In this study, in the lower thoracic spine, 5.4% to 9.5% of the discs, depending on level, were qualitatively assessed as moderately to severely narrowed. Anterior bulging was more common than posterior, which was relatively rare and mild when present. Signal was lower in the midthoracic than lower discs. At least 1 moderate or severe vertebral deformity was found in 6.1% of the subjects, suggesting fracture, and hemangiomas were identified in 2.3% of subjects.

In 2014, Miyazaki et al. [12] reported retrospective cohort study of prevalence and distribution of cervical and thoracic compressive lesions of the spinal cord in lumbar degenerative disease. In this article, the DISH was present in 25.6% of patients (72/281). The prevalence of DISH in the 41–49, 50–59, 60–69, 70–79, and ≥80 year age groups was 8.3% (2/24), 9.8% (5/51), 16.0% (12/75), 49.5% (48/97), and 33.3% (4/12), respectively; the prevalence increased with age. The average number of fused vertebral bodies was 7.5. More than 80% of DISH was located from T7 to T11, and more than 95% of DISH was located at T9/10. Patients with DISH were significantly older (71.1 years vs. 60.9 years), and men were more likely to have DISH than women.

In 2014, Schairer et al. [13] reported a retrospective cohort study of the increased prevalence of cervical spondylosis in patients with adult thoracolumbar spinal deformity. In this article, a total of 47,560 patients were included in this study. Cervical spondylosis occurred in 13.1% overall, but was found in 31.0% of patients with thoracolumbar spinal deformity. Similarly, thoracolumbar spinal deformity was found in 10.7% of patients overall, but was increased at 23.5% in patients with cervical spondylosis.

Moon et al. [36] reported prevalence, distribution, and significance of incidental thoracic OLF in Korean patients with back or leg pain. In this study, the prevalence of thoracic OLF in total patients was 16.9% (360/2,134). The prevalence tended to increase with aging and was higher in women than in men. The lower thoracic segment of T10-11 was the most frequently affected segment. Of the 360 patients with OLF, 31.9% had coexisting herniated thoracic discs at the same level. Approximately 74% of the patients with OLF had coexisting lumbar and cervical disease. Nine (2.5%) of 360 OLF patients underwent surgery for thoracic lesion.

Park et al. [37] reported among the 460 patients with lumbar stenosis, 110 (23.9%) had concurrent radiologic cervical stenosis and 112 (24.3%) had concurrent radiologic thoracic stenosis. Fifty-six patients (12.1%) had combined radiologic cervical and thoracic stenosis in addition to their symptomatic lumbar stenosis (triple stenosis). Anterior epidural stenosis at C7-T1 was associated with a high prevalence of thoracic stenosis.

Mori et al. [38] reported prevalence and distribution of ossification of the supra/interspinous ligaments (OSIL) in symptomatic patients with cervical ossification of the posterior longitudinal ligament of the spine. In this study, a total of 234 patients with a mean age of 65 years was recruited. The CT-based evidence of OSIL was noted in 68 (54 males and 14 females) patients (29%). The distribution of OSIL showed a significant thoracic preponderance. In OSIL-positive patients, single-level involvement was noted in 19 cases (28%), whereas 49 cases (72%) presented multi-level involvement. We found a significant positive correlation between the OP-index gradevand OSI-index. ONL was noted at a significantly higher rate in OSIL-positive patients compared to negative patients

Han and Jang [39] reported prevalence and distribution of incidental thoracic disc herniation (TDH), and thoracic hypertrophied ligamentum flavum. The prevalence rates of TDH and thoracic HLFS in all patients were 6.5% (145/2,212) and 19.0% (421/2,212), respectively. The prevalence of TDH was demonstrated as a relatively even distribution across age groups higher in male participants (8.0%) than in female participants, and more frequent in patients with lumbar surgical lesions (8.2%) than without surgical lesions. Whereas, the prevalence of thoracic HLFS tended to increase with age, was higher in female participants (21.6%) than in male participants, and had no association with presence of lumbar surgical lesions. The most frequently involved segments of TDH and HLFS were T8/9 and T10/11, respectively. Six of 145 patients with TDH and 15 of 421 patients with HLFS underwent surgery.

In 2020, Siller et al. [40] reported the retrospective study of surgery of degenerative thoracic spinal stenosis-long-term outcome with quality-of-life after posterior decompression via a uni- or bilateral approach. In this study, From 645 patients with surgery for degenerative spondylotic myelopathy within 6 years, 28 patients (4.3%) suffered from thoracic spinal stenosis. Median age was 70.4 years with a slight predominance of the female sex. The most frequent symptoms (mean duration 7.6 months) were ataxia (61%) and sensory changes (50%).

In 2020, Chen et al. [41] reported the review article of the prevalence and clinical characteristics of thoracic spinal stenosis: a systematic review. In this study, a total of 129 studies including 1,935 subjects were selected, of which 361 (18.7%) were diagnosed with OPLL, 804 (41.5%) with OLF, 143 (7.4%) with OPLL+OLF and 627 (32.4%) with TDH. Most reports were from China, Japan and USA. Thoracic OPLL occurred mostly at the middle-thoracic spine (43.4%), while OLF predominately occurred at the lower-thoracic spine (63.1%). TDH was mainly localized in the middle (46.0%) and lower-thoracic (50.3%) spine. Thirty-two studies involving 524 patients described tandem spinal stenosis, of which 52.1% had accompanying cervical diseases and 35.9% lumbar diseases.

In 2021, Mesregah et al. [42] reported a cross-sectional MRI study of trends and patterns of thoracic intervertebral disc degeneration in symptomatic subjects. In this study, the total grade of IVD degeneration and the number of degenerated levels increased with increasing age. The most common degenerated level was T6/7 (13.3%), while the least common degenerated level was T12/L1 (1.8%). The most common grades were grade I in group 1 (60.5%), grade II in groups 2 (39%) and 3 (37.3%), and grade III in groups 4 (42.5%) and 5 (44.6%).

Yoshihara et al. [43] reported prevalence and characteristics of thoracic ossification of the posterior longitudinal ligament in 3,299 Black patients. In this study, the prevalence of T-OPLL was 1.5% (50 patients), with 2.4% for females and 0.8% for males. The highest prevalence was observed in patients at the age of 70 years (3.8%). Thickness of T-OPLL was between 2 and 3mm in 46% (23/50) of the patients, and the largest thickness was 6.1 mm. T-OPLL was significantly associated with female sex and the presence of DM.