OALL / DISH (Cervical Hyperostosis)

Definition

• DISH (Forestier disease) is a systemic, non-inflammatory enthesopathy causing "flowing" ossification of spinal ligaments and peripheral entheses, sparing the disc and synovial joints.
• OALL (ossification of the anterior longitudinal ligament) is the cervical expression that grows anteriorly, compressing the pharynx, oesophagus and airway rather than the cord.

Key epidemiology (global)

• Radiographic prevalence rises with age: roughly 10 percent over 50 years and up to 25-30 percent over 70 years in autopsy and CT cohorts.
• Male predominance (about 2:1); rare under 40 years.
• Cervical osteophytes are most marked at C3-C6; symptomatic dysphagia affects a minority (often quoted under 20 percent of those with cervical DISH).
• Strongly linked to metabolic syndrome (type 2 diabetes, obesity, hypertension) — DISH is increasingly viewed as a metabolic bone phenotype, not simple "wear and tear".
• The rigid, brittle "bamboo-like" spine fractures easily after low-energy trauma (chalk-stick fractures) with a high rate of neurological injury.

The Anterior Longitudinal Ligament (ALL)

• Broad ligament covering the anterior vertebral bodies.
• Prevents hyperextension.
• In DISH, it ossifies but spares the annulus fibrosus and nucleus pulposus (unlike Ankylosing Spondylitis).

The Swallowing Mechanism

1. Phase 1 (Oral): Bolus prep.
2. Phase 2 (Pharyngeal): Pharynx constricts, Hyoid elevates, Epiglottis inverts.
3. Phase 3 (Esophageal): Peristalsis. OALL disrupts Phase 2 by physically blocking epiglottic inversion or narrowing the pharyngeal space.

Presentation

• Dysphagia: Most common presenting symptom of cervical OALL (a minority of all cervical DISH). "Food sticking".
• Globus Sensation: Feeling of a lump in the throat.
• Dysphonia: Hoarseness (RLN compression or vocal cord edema).
• Stiffness: Decreased cervical ROM.
• Dyspnea: Rare, caused by laryngeal edema or massive C3 osteophyte compressing glottis.

Examination

• Palpation: Hard, bony mass palpable in the posterior pharynx (beware gag reflex).
• Neck: Stiffness, loss of extension.
• Neuro: Usually normal (OALL grows OUT, not IN to the canal).

First Line Treatment

• Dietary Modification: Soft foods, thicken fluids (Speech Pathology involvement).
• NSAIDs: Reduce soft tissue inflammation around the osteophytes.
• Steroids: Short course for acute flare of dysphagia.
• Review: Monitor weight and aspiration signs.

• Airway: Monitor for retropharyngeal hematoma / edema (Stridor).
• Feeding: Nasogastric feeding may be needed if esophageal repair done or severe edema.
• Swallow Study: Repeat contrast swallow before oral intake if dura/esophagus concerns.

• Success Rate: High for dysphagia resolution — improvement in about 95 percent of operated patients in the largest pooled series.
• Aspiration: May not resolve if the cause was neurological or permanent muscle damage.
• QoL: Significant improvement in eating ability.

Global epidemiology

• Radiographic DISH is common worldwide in older adults: roughly 10 percent over 50 and 25-30 percent over 70, with consistent male predominance across European, North American and Asian CT/autopsy cohorts.
• Population studies repeatedly tie DISH to metabolic syndrome, so prevalence tracks with regional obesity and type 2 diabetes burden.
• Symptomatic cervical OALL (dysphagia or airway obstruction) remains uncommon, and the published surgical literature is dominated by case reports and small series — no randomised data exist.

Registry & practice variation

• There is no implant registry relevant to OALL because osteophytectomy is usually fusion-free; registry data (NJR, AOANJRR, AJRR) only apply if an instrumented fusion is added for instability or a chalk-stick fracture.
• Well-resourced settings: video fluoroscopic swallow study, CT planning, ENT nasendoscopy and awake fiberoptic intubation are standard before surgery.
• Limited-resource settings: diagnosis often rests on plain lateral radiographs and barium swallow; dietary modification and speech-pathology input carry most of the load, with surgery reserved for severe weight loss or aspiration.

• No high-level evidence: the entire surgical literature is case reports and small series; there are no randomised trials or formal guidelines, so recommendations are consensus-based (Harlianto/Verlaan systematic review).
• Fusion vs osteophytectomy alone: most authors avoid routine fusion to spare adjacent-segment disease and operative time, reserving it for instability or iatrogenic disc violation — but the threshold is not standardised.
• Defining "mechanical" dysphagia: dysphagia in elderly DISH patients is often multifactorial (neurological, presbyphagia, reflux). A positive swallow study does not guarantee the osteophyte is the sole cause, and a subset have persistent symptoms after technically successful surgery.
• Predicting recurrence: radiographic regrowth is common yet symptomatic recurrence is rare (~4 percent); no reliable predictor or proven preventive (bisphosphonates, metabolic control) exists.
• Imaging in trauma: whether every ankylosed-spine trauma patient needs MRI in addition to CT remains debated — current data suggest selective use for neurological deficit or suspected disco-ligamentous injury.