Neurosurgeon Dr. Milton Avol surrendered in Los Angeles Municipal Court to begin serving a 30-day jail sentence for violating probation by failing to eliminate slum conditions at several of his apartment buildings. At the completion of his jail term, Avol, of Beverly Hills, will be required to spend 30 days under house arrest at one of his buildings at 1660 N. Western Ave., Deputy City Atty. Stephanie Sautner said. Judge Veronica Simmons-McBeth, who imposed the unusual sentence in 1985, will visit the Western Avenue building next week along with lawyers for both sides to select a suitable apartment for Avol, Sautner said. Avol, 63, has sold the Bixel Street building where he was originally ordered to serve the house arrest.