Apprentice Michael Straight underwent what his twin brother and fellow rider termed "successful" surgery Thursday evening, some 24 hours after being critically injured in a one-horse spill at Arlington Park in Arlington Heights, Ill.\nMatthew Straight, speaking on behalf of his family, issued a media release Friday morning that said surgeons at Lutheran General Hospital in Park Ridge, Ill., had operated on his brother to attempt to stabilize his spinal injuries, which include four fractured vertebrae. Fear persists that Michael Straight, 23, might be paralyzed from the waist down, but his brother made no mention of the long-term implications of the injuries.\n"The doctors said it could not have gone any better," Matthew Straight said in the release. "We know there is still a long way to go, and now it's just a waiting game to see how good and how quick he heals up. We know it's going to be a long road back and we're not going anywhere."\nDoctors previously had said to "pray for the best but prepare for the worst" and that the prognosis for Straight being able to walk again was "very grim," according to a family friend speaking on condition of anonymity. The friend also said a flexible rod had been inserted by doctors during the spinal procedure and that all accounts of the surgery were that it went very well.\nMatthew Straight said he and his parents appreciated the outpouring of support in the aftermath of the incident and asked that the family's privacy be respected. "When we feel it is the appropriate time to talk more publicly, we will do so," said Straight, adding the family would issue periodic updates through the Arlington media-relations office.\nMichael Straight was injured in the 1 1/16-mile Polytrack race when his mount, Im No Gentleman, fell suddenly when appearing to clip the heels of Conte Ridge nearing the quarter pole.\nMichael Straight graduated last year from the North American Riding Academy, the school founded and operated in Lexington, Ky., by retired Hall of Fame jockey Chris McCarron. Matthew Straight graduated from the McCarron riding academy one year earlier and most recently has competed at Ellis Park in Kentucky.\nThe Straight brothers grew up in East Greenbush, N.Y., and became interested in the sport by attending the races at nearby Saratoga. Michael won with the first mount of his career on March 6 at Tampa Bay Downs. In all, he has ridden 39 winners from 372 mounts, with 23 of his wins coming at Arlington.\nThe spill was the second at the Arlington meet that resulted in severe injury. Rene Douglas suffered a major spinal injury in a May 23 race and continues to recuperate in the Chicago area.