Partitioning the labyrinth for benign paroxysmal positional vertigo: clinical and histologic findings.

The incidence of benign paroxysmal positional vertigo (BPPV) has been documented at 17 percent of all vertiginous patients. Partitioning of the labyrinth is a laser technique for resolution of BPPV. In 1991 Anthony partitioned the posterior semicircular canal of two patients and eliminated their BPPV in 24 hours, which was much sooner than anticipated. This paper presents an animal study that was undertaken to determine why laser partitioning of the posterior semicircular canal resolved BPPV so promptly. The histologic changes 24 hours post-partitioning in the guinea pig showed bony semicircular canal fistula creation, and constriction of the membranous semicircular canal. The constriction caused decreased endolymphatic flow and led to BPPV-resolving long-term obstruction of the membranous canal described by Wilpizeski. Also, the clinical study of the application of partitioning to 14 patients with BPPV is described. The technique under investigation provided the resolution of positional vertigo within 7 days in most cases, and within 8 weeks in all uncomplicated cases. Results included some temporary postoperative motion sensitivity for 6-8 weeks, a transient sensorineural hearing loss in 6 of 14 (43%) patients, and a permanent hearing loss in one (7%) insulin-dependent diabetic patient. Location of the partition on the posterior semicircular canal did not affect the resolution of BPPV, the incidence of transient hearing loss, or the motion sensitivity. Partitioning provided prompt, permanent resolution of BPPV and did not put the hearing at risk in nondiabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)