Diffuse idiopathic skeletal hyperostosis in ancient clergymen
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- Verlaan, J., Oner, F. & Maat, G. Eur Spine J (2007) 16: 1129. doi:10.1007/s00586-007-0342-x
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Diffuse idiopathic skeletal hyperostosis (DISH) is a common but often unrecognized systemic disorder observed mainly in the elderly. DISH is diagnosed when the anterior longitudinal ligament of the spine is ossified on at least four contiguous spinal levels or when multiple peripheral enthesopathies are present. The etiology of DISH is unknown but previous studies have shown a strong association with obesity and insulin-independent diabetes mellitus. DISH can lead to back pain, dysphagia, myelopathy, musculoskeletal impairment and grossly unstable spine fractures after minor trauma. In archeological studies a high prevalence of DISH has been demonstrated in ancient clergymen. The present study describes the pathological changes of human remains excavated from the abbey court (Pandhof) in the city of Maastricht, The Netherlands. Human remains of 51 individuals buried between 275 and 1795 ce were excavated and examined. The remains were investigated according to a standardized physical anthropological report and individuals demonstrating ossification of spinal ligaments and/or multiple peripheral enthesopathies were included in the study group. The authors reviewed all available material and after reaching consensus, each abnormality found was given a diagnosis and subsequently recorded. After examination, 28 individuals were considered to be adult males; 11 adult females; three adults of indeterminate sex and nine individuals were of sub adult age. The mean age at death for adults was 36.8 years. Seventeen adult individuals (40.4% of all adults), displayed ossifications of at least four contiguous spinal levels and/or multiple enthesopathies of the appendicular skeleton and were therefore, assigned the diagnosis DISH. The mean age of these individuals was 49.5 ± 13.0 years. In at least three of these individuals, DISH had led to extensive ossification and subsequent ankylosis of axial and peripheral skeletal structures. In this population of (presumably) clergymen and high-ranking citizens, DISH was observed in unusual high numbers at a relatively young age. Some of the examined cases suggest that DISH may be a seriously incapacitating disorder when the more advanced stages of the disease have been reached. It is hypothesized that “a monastic way of life” can predispose to DISH. Present demographic trends in obesity and diabetes mellitus as potential co-factors for the development of DISH warrant further study to investigate its future prevalence.
KeywordsDiffuse idiopathic skeletal hyperostosis Osteoarchaeology Paleopathology Spinal ankylosis
Diffuse idiopathic skeletal hyperostosis (DISH) is a common but often unrecognized systemic disorder observed mainly in the elderly . DISH is diagnosed when ossification of the anterolateral aspect of the anterior longitudinal ligament is present on at least four contiguous spinal levels without involvement of the intervertebral disk space and/or apophyseal (facet) joints . The disease can manifest itself also at extraspinal locations leading to peripheral entheseal ossification and bony spurs [3, 4]. Studies investigating the demographic characteristics of DISH have found a prevalence ranging from 2.9% in the Korean population, to 10.0% in a Caucasian population with a male/female ratio of 2:1 in most investigations [5, 6]. All papers pertinent to DISH demonstrate a consistent and marked increase of the disease with advancing age . Its etiology is unknown but several publications have found correlations with metabolic disorders, especially high body mass index and insulin-independent diabetes mellitus [8, 9, 10]. The difference in prevalence between ethnic groups also suggests genetic factors being involved in the etiology of the disorder [5, 6, 11].
From paleopathological studies it becomes apparent that DISH is not a disorder from recent history. Its features have for example been demonstrated in the excavated remains of an Italian female individual who lived six centuries CE (Common Era); in the Egyptian pharaoh Ramses II (1302–1213 BCE); and in hominid specimens as old as the Neandertal Shanidar I living approximately 50,000 years ago [12, 13, 14, 15]. Signs of DISH have even been shown in dinosaurs . Although the radiological manifestations of DISH can sometimes be quite dramatic, displaying extensive ossification of ligamentary structures, its clinical symptoms are usually relatively mild . Some authors have described severe dysphagia, progressive airway obstruction, obstructive sleep apnea and difficult endotracheal intubation due to anterior cervical bony protuberances while others have noted minor stiffness or mild pain when the abnormalities were located in the thoracic or lumbar spine [18, 19]. The presence of DISH has been associated with unstable spinal fractures, often complicated by permanent neurological deficit, following minor trauma [20, 21]. Still other studies could not confirm these findings and concluded that DISH is a strict radiological observation without clinical relevance [22, 23]. Presently, medical or surgical intervention is considered necessary for symptomatic treatment in rare cases only.
An archaeological investigation of the Pandhof site was performed and the artifacts found were dated by stratigraphy (dating based on geological superposition of artifacts), and/or seriation (dating using the change of ‘fashion’ of artifacts over time to estimate the year of burial). After completion of the archaeological examination the excavated human remains were packed individually and sent to our department. After the bones of each individual were reconstructed, the joints were articulated and the human remains investigated according to a standardized physical anthropological report . For all excavated individuals, attempts were made to assess sex, age at death and stature. Subsequently, they were examined for pathological conditions and individuals demonstrating spinal ligament ossifications of four or more contiguous vertebral levels and/or extensive peripheral enthesopathies were included in the study group . Two authors reviewed all available material and after reaching consensus, each abnormality found was given a diagnosis and recorded. Furthermore, all archaeological records were retrieved to obtain information about estimated year of burial and possible clues to social status or identification.
Characteristics of 17 individuals with diffuse idiopathic skeletal hyperostosis
Age interval (years)
Estimated age (years)
Miscellaneous pathologic conditions
Spina bifida occulta S1; sacralization L5; ossification of acetabular labrum; osteochondritis dissecans knee
Calcanear spurring; iliac whiskering; torus palatinus
Osteochondritis dissecans; rachitis; iliac whiskering; occipital prominence
Vertebral osteoarthritis; healed fractured ribs (left Th4, Th5); ossification of glenohumeral soft tissues; extensive ankylosis of thoracic cage
Vertebral osteophytosis; olecranon tufting
Calcanear spurring; iliac whiskering; ossification of ischial tubercle / origo of femoral muscle / iliolumbal ligament / glenoid labrum
Allen’s fossa; interosseous membrane; patellar tufting
Bilateral osteomyelitis tibia and fibula; vertebral osteophytosis
Sacralization L5; osteochondritis dissecans of left shoulder and left knee
Cervical vertebral osteophytosis
Avulsion fracture Th8; fracture phalanx digit I; olecranon tufting
Three individuals, from grave 25, 43 and 44 are illustrative examples of DISH and are presented in more detail below.
Case grave 25
Case grave 43
Case grave 44
Diffuse idiopathic skeletal hyperostosis (DISH) was first described by Forestier  in the early fifties and subsequently named after him. When it became clear that peripheral enthesopathies frequently accompanied spinal pathology, suggesting a systemic skeletal condition instead of an isolated spinal disease, the name was changed into diffuse idiopathic skeletal hyperostosis to better describe the wide range of abnormalities possible . DISH can be distinguished from other ankylosing diseases such as ankylosing spondylitis (Morbus Von Bechterew), because bony joints, especially the sacroiliac joints are by definition preserved in DISH .
Ossification of the posterior longitudinal ligament (OPLL) is a disease probably strongly related to DISH and has been studied in depth especially in Japan where it is a common condition . Inamasu et al.  suggest from their literature review of previously conducted research on OPLL that it is probably not a single-gene disease; that pathways by which osteogenic induction of spinal ligament cells might occur are as yet poorly understood and that bone synthesis marker concentrations have not differed significantly from control groups. It is currently unknown whether the results obtained from research on OPLL may be applicable to DISH as well .
In the population excavated from the ‘Pandhof’ of the OLVK in the city of Maastricht, DISH was the most frequently encountered pathology. Seventeen individuals with an average age at death of 49.5 years were diagnosed with this condition on the basis of spinal ligament ossification or multiple peripheral enthesopathies. The percentage of adult individuals with DISH therefore, was 40.4%. This is an unusual high percentage of DISH in a relatively young population compared to results from radiological studies in the literature [7, 11]. In the study by Rogers and Waldron , DISH was found to be present in 11.5% (6 out of 52 excavated males), of the population buried in the church and chapels from The Royal Mint Medieval site in London while the prevalence of DISH in a nearby lay cemetery where the general population (likely to be peasants/farmers), was buried, was 0% (0 out of 99 males). They suggested this difference in prevalence (11.5 vs. 0%) to be caused by a difference in occupation and access to food . In the present study the prevalence of DISH was almost fourfold that reported by Rogers and co-authors. Janssen and Maat , found in their paleopathological study DISH to be present in 100% of the inspected clergymen (N = 27, with a mean age of 56 years ranging from 43 to 75 years and living between 1070 and 1521 CE) excavated from the Saint Servaas Basilica also in the city of Maastricht. Since the present study group has in common with the clergymen from the Saint Servaas Basilica that the individuals were probably enjoying a high status (as can be concluded from the location of their burial within the confines of the church normally reserved for priests, monks and high-status citizens), and likely had plentiful supply of food, it is not unreasonable to suggest that the associated ‘monastic way of life’, a term coined by Rogers and Waldron , may have predisposed to DISH [33, 35]. From descriptions of the dietary habits of monks in the Middle Ages in the discussion section of the Rogers article, it can be argued that saturated (animal-) fats combined with small portions of vegetables and ample alcoholic beverages may have often been on the menu, not unlike the diet of a considerable part of modern Western society. The 17 individuals with DISH from the present study were buried in the interval 450–1795 CE. Therefore, it is hypothesised that the interred of the OLVK (and the Merovingian Church before that), may in general have had an abundant food supply during this time period. Although genetic factors may play an important role in the etiology of DISH, to our best knowledge, no historical evidence suggests a closer genetical relationship between monks than between the general population and monks, therefore, a genetical predisposition for monks to develop DISH cannot be demonstrated. From current research it can be learned that high body mass index and insulin-independent diabetes mellitus are risk factors for developing DISH further supporting, though certainly not proving, that the lifestyle of ancient clergymen (sedentary work; abundance of food), may have predisposed them to develop DISH [36, 37].
Examination of the skeletal material with severe abnormalities suggests that DISH may have seriously affected the locomotor and probably also cardiopulmonary apparatus of individuals with this condition. For example, ankylosis of the thoracic cage forced the individual from grave 25 to ventilate by diaphragm contraction only and this would have led to restriction of pulmonary function and subsequent physical impairment. Furthermore, when the physiological range of motion of multiple bony joints from the axial and peripheral skeleton becomes limited due to surrounding soft tissue ossification, it is not unreasonable to suggest that affected individuals may have had clinical symptoms that are detectable by physical examination. The individual from grave 25 probably also suffered from restricted abduction and endorotation (estimated to be between 45–60 degrees for both maneuvers before ossified soft tissue impingement), in the left glenohumeral joint. Due to postmortem absence of the articular surface of the humeral head on the contralateral side, no right shoulder impingement could be estimated.
In conclusion, DISH may actually be a clinically relevant condition although presumably only so when the more advanced stages of the disease have been reached. Regarding the presently known clinical symptoms, the diagnosis DISH should be considered in patients of middle or advanced age with unexplainable back pain or peripheral arthralgia and/or restricted motion and should alert the physician for the presence of fracture dislocations in DISH patients complaining of back pain after relatively minor trauma .
The authors would like to thank Joost Roelofs for his technical assistance during the acquisition of computed tomography data from the skeletal material.