Which canal is affected in Benign Paroxysmal Positional Vertigo (BPPV)?

From the Guidelines

BPPV most commonly affects the posterior semicircular canal of the inner ear, with approximately 85-95% of cases involving this canal. This condition occurs when calcium carbonate crystals (otoconia) become dislodged from the utricle and migrate into the semicircular canals, creating an abnormal fluid displacement that sends false signals about head position to the brain, resulting in brief episodes of vertigo 1. The posterior canal's anatomical position makes it particularly susceptible to these displaced crystals due to its lower position when a person is upright, allowing gravity to naturally draw the otoconia into this canal.

Key Points

• The posterior semicircular canal is the most commonly affected canal in BPPV, accounting for approximately 85-95% of cases 1.
• The Dix-Hallpike maneuver is used to diagnose posterior semicircular canal BPPV, with a strong recommendation based on diagnostic studies with minor limitations and a preponderance of benefit over harm 1.
• Lateral (horizontal) canal BPPV is the second most common type of BPPV, accounting for approximately 5-15% of cases, and is diagnosed using the supine roll test 1.
• The Epley maneuver, which specifically targets the posterior canal, is the most commonly used repositioning technique for treating BPPV.

Diagnosis and Treatment

The diagnosis of BPPV is based on the patient's history and physical examination, including the use of provocative maneuvers such as the Dix-Hallpike test and the supine roll test 1. Treatment of BPPV typically involves canalith repositioning procedures, such as the Epley maneuver, which are designed to relocate the dislodged otoconia and relieve symptoms 1.

Quality of Life

Patients with BPPV experience effects on individual health-related quality of life, and utility measures demonstrate that treatment of BPPV results in improvement in quality of life 1. Therefore, accurate diagnosis and effective treatment of BPPV are essential to improve patient outcomes and quality of life.

From the Research

Benign Paroxysmal Positional Vertigo (BPPV) and Affected Canals

• The posterior and/or lateral semicircular canals are usually affected in BPPV 2
• The pathophysiology of BPPV is canalolithiasis comprising free-floating otoconial debris within the endolymph of a semicircular canal, or cupulolithiasis comprising otoconial debris adherent to the cupula 2
• Multiple canal BPPV, where more than one semicircular canal is involved, can occur in 6.8-20% of cases 3
• The most common combination of involved canals in multiple canal BPPV is ipsilateral posterior and horizontal semicircular canals 3
• The posterior canal is the most common canal affected, followed by the lateral canal 4

Specific Canals Affected

• Posterior semicircular canal: most common canal affected, with a higher incidence and prevalence than lateral and anterior semicircular canals 5
• Lateral semicircular canal: can be affected, with apogeotropic and geotropic variants 4
• Anterior semicircular canal: less commonly affected than posterior and lateral canals 5

Diagnosis and Treatment

• Diagnosis of BPPV involves observation of positional and/or positioning nystagmus, which is essential for accurate diagnosis 2
• Treatment of BPPV typically involves canalith repositioning procedures, such as the Epley maneuver, Semont maneuver, and Brandt-Daroff exercise 5, 6