Lateral Semicircular Canal BPPV ... Are We Still Ignorant?

Benign Paroxysmal Vertigo is one of the most common causes of vertigo. The most common semicircular canal involved in pathogenesis of BPPV is Posterior semicircular canal. However anterior and lateral semicircular canals can also sometimes be responsible for BPPV but their involvement in pathogenesis is still underrated. The incidence of lateral semicircular canal BPPV is in literature is around 10-12% while anterior canal is about 3%. The main objective of this study was to provide the database for incidence of lateral canal BPPV from a tertiary care hospital with the aim that more clinicians incorporate this entity into their differential diagnosis when their cases of posterior canal BPPV are refractory. This was an observational cross-sectional study of 300 patients of BPPV who were coming in ENT OPD as primum or as referral. All the patients underwent both the Dix-Hallpike maneuver as well as the supine roll test. The patients who were having upbeating torsional vertical nystagmus on Dix-Hallpike were treated on lines of posterior canal BPPV whereas those with horizontal nystagmus on supine roll test were treated on lines of lateral canal BPPV. The data was tabulated and analysed for the incidence of lateral canal BPPV. Out of 300 patients; 188 were males and 122 were females. Most commonly affected age group by BPPV was 40-50 years. Out of 300 cases 260 cases (86.6%) had posterior BPPV and 37 cases (12.3%) had lateral canal BPPV. 3 cases (1%) also had anterior canal BPPV. 30/37 cases of lateral BPPV had geotropic nystagmus while 7 cases had apo-geotropic nystagmus. Posterior canal BPPv was treated by Epleys maneuver. Superior canal BPPV was treated by Yacovino maneuver. The cases of lateral canal BPPV were treated by either Vannucchi-asprella; Gufoni; Lempert maneuver or by the combination of two maneuvers. Lateral canal BPPV is an important diagnosis to consider in all cases of BPPV. Its true incidence is still under blanket as many clinicians are not using supine roll test routinely in their practice while diagnosing BPPV. Many refractory cases of BPPV can be cured if the involvement of other canals in its pathogenesis is kept in the mind so that correct diagnostic and repositioning maneuvers can be applied. We also encourage more institutional studies on lateral canal BPPV so that a standard treatment protocol with clear indications can be designed for this entity as is available for BPPV.