Imagine Dragons has a hit single on rock radio and a hotly anticipated album hitting stores in less than a month. Too bad the group's singer can't utter a word.

The Las Vegas alt-rock band's frontman, Dan Reynolds, underwent surgery in early August to remove a polyp on his vocal cord, which he detected after the group performed a whopping 14 shows in the span of three days at South by Southwest (SXSW) earlier this year. Those shows were part of a hectic promotional run that helped the band's anthemic single, "It's Time," climb to No. 4 on Billboard's Alternative chart in June and so far sell 356,000 downloads, according to Nielsen SoundScan. Imagine Dragons' debut album, "Night Visions" (Interscope), is due Sept. 4. Until then, a recovering Reynolds is on "complete vocal silence," hoping to get past this setback, which has sidelined many artists recently.

"At first, it was devastating for me," Reynolds wrote in an email, "but after I've heard all the success stories of other artists who go through the same thing, I felt a lot more at ease."

If all goes according to plan, Reynolds' voice will be healed enough to lead Imagine Dragons when the band kicks off a North American fall tour on Sept. 5. Other vocalists haven't been so lucky. An outbreak of voice issues among singers of various genres -- from Maxwell to Keith Urban to Florence Welch -- has led to the reshuffling or cancellation of dozens of live dates during the past year. These problems include abnormal growths like polyps, cysts and nodules. Their causes can be behavioral (hazards of life on the road, like overperforming and too much alcohol, can be contributing factors) or genetic. If not treated, they can lead to permanent scarring and too-short careers.

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For some, vocal problems have resulted in a massive monetary loss: For instance, a hemorrhaged vocal cord forced Adele to scrap 16 U.S. theater and club shows last fall, at the pinnacle of her "21" success. Earlier in 2011, 10 sold-out Adele performances at similarly sized venues grossed $1.9 million, according to Billboard Boxscore.

For others, like John Mayer, voice problems can derail the rollout of a new project. In March, less than two weeks after announcing a spring tour in support of his fifth studio album, "Born and Raised," Mayer revealed that the surgery he'd undergone last year to remove granuloma, an inflammatory collection of cells, hadn't properly healed. More surgery was needed, and the 18-city tour was scrapped. No timetable has yet been set for the live return of an artist who grossed $28.1 million from 45 shows in 2010.

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Although "Born and Raised" debuted atop the Billboard 200 and has sold 442,000 copies since its May release, according to SoundScan, Mayer will need vocal surgery before the end of the summer, and an undefined recuperation period will follow. "The recovery process isn't easy, and you literally can't talk for weeks," says Michael McDonald, Mayer's manager. "Caffeine, alcohol, spicy foods -- all that stuff is out of your diet, so you literally have to just sit in silence for a period until you can talk."

Dr. C. Gaelyn Garrett, medical director of the Vanderbilt Voice Center in Nashville, says that the recent uptick in vocal issues isn't the result of any new epidemic, but of a new willingness for artists to step forward and publicly address their physical ailments. Hip-hop star Nicki Minaj, for instance, gave a shout-out to her vocal doctor during a performance at New York's Roseland Ballroom on Aug. 14. Days later, Minaj canceled a performance at the U.K.'s V Festival due to strained vocal cords.

"You used to hear a lot of people say they had bad allergies or vocal fatigue, and they just need to rest," says Garrett, who has treated artists like Willie Nelson, Gary Allan and Shania Twain in her 18 years at Vanderbilt. "A lot of those times it was actually -- I don't want to say a cover-up -- [but] they just didn't want to let the general public know that they had anything physically wrong with their voice."

Furthermore, as fiber-optic technology and laser surgery have improved during the past decade, vocal specialists have been able to identify vocal damage more frequently and treat setbacks before they become chronic, career-crippling issues. According to Garrett, taking a singer for regular checkups before a problem exists is crucial. Not only do doctor visits establish a "baseline exam" of vocal cords and folds to use if a problem does arise, but they also keep artists educated about vocal care. At a specialty center like Vanderbilt, artists can interact with a team of physicians, speech pathologists and singing specialists to understand whether they're performing in a range that's natural for the shape of their larynx, or speaking in a manner that damages their skills.

But many musicians, particularly those at the early stages of their career without the financial support of a label or manager, aren't so lucky. And serious issues can still occur in spite of preventative checkups. Mayer's granuloma, for example, was diagnosed after the singer/songwriter had developed regular relationships with throat doctors during his career, according to McDonald. And although there are major-label artists who neglect doctor visits before problems crop up -- Imagine Dragons' Reynolds admits that he didn't get a checkup until he noticed something was wrong after his band's SXSW marathon -- Garrett believes that most managers are getting smarter about tending to their singers' long-term needs. "Management has now recognized that this is not a sprint for the artist. It's a marathon, and a lot of the new artists that they're signing, they're sending them over right from the beginning," she says.

Unfortunately, the demands of music promotion often combat increased medical awareness. With album sales no longer as important to establishing artist visibility as touring and TV appearances, an exhausting performance agenda can leave a singer's vocals strained. Pop singer/songwriter Santigold says that a rigorous touring and interview schedule contributed to vocal swelling issues in the past. "A big part of the problem nowadays is that artists are required to do too much at once," she says.

Former Atlantic Records president Ron Shapiro, who heads Ron Shapiro Management and Consulting, agrees that too much promotion is causing too many vocal problems, but says that it's simply a symptom of major-label marketing in 2012. The new economics of the music industry, he notes, have left labels more concerned with saturating the marketplace and less concerned with the long lead on an artist's career.

"The level of investment that [labels] will generally make seems to be shrinking and shrinking all the time, even when they have so-called 360 participation," says Shapiro, who manages such acts as Regina Spektor and BeBe Winans.

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These circumstances can be especially nerve-racking for a little-known artist trying to establish his or her voice as it physically decays. Pop-rock singer Christina Perri, best-known for her 2010 hit "Jar of Hearts," says that a Los Angeles ear-nose-throat doctor found a congenital cyst on her vocal cords in August 2010, one month after she signed a deal with Atlantic Records and just after "Hearts" made its network TV debut on "So You Think You Can Dance." The doctor told her that it was the sort of condition that would eventually require surgery.

"My career had just started," Perri says. "I was like, 'What? I can't have surgery now.' And everyone, like the label and my manager, were like, 'It's really not the time.' There's no way I could've stopped." Perri underwent surgery in Boston in August 2011, after a year of performing that was physically "difficult and challenging," and her voice only returned to feeling 100% earlier this summer.

Shapiro understands the allure of capitalizing on momentum, but says that maintaining an artist's voice -- the instrument he describes as "the cornerstone of everything" -- always comes first. When one of his artists has to grapple with a vocal issue, concert dates are often canceled. However, announcing a makeup date whenever possible, within 24-48 hours of the cancellation, is also important for assuaging disgruntled fans. "Even if [the return date is] three months, four months away," Shapiro says. "We try never, if at all possible, to leave people who bought tickets to not have a chance."

Of course, there are safeguards against losing a string of shows or an entire tour. John Meglen, president/co-CEO of Concerts West/AEG Live, says that insurance options include cancellation insurance, which expects a show or two to be canceled without any makeup dates, and an abandonment policy, in which an entire tour must be canceled in the wake of a serious problem, health-related or otherwise. Meglen dealt with show cancellations in March, when Celine Dion scrapped 10 performances during her AEG-produced residency at the Colosseum at Caesars Palace in Las Vegas due to weakness in her right vocal cord.

Dion eventually made up the canceled shows as her residency progressed, and aside from the operating expenses of the scrapped concerts, no major revenue was lost by the artist. But Meglen points out that a standard tour may require a different insurance plan than a residency, in which artists stay in one place. "I prefer abandonment insurance in those types of [residency] situations, because we have a built-in mechanism that allows us to reschedule," he says, "whereas on a tour, you don't necessarily have that. You may lose a handful of shows."

Medical advancements are being made: Garrett says researchers at Vanderbilt are looking at improving wound healing for voice trauma, while laryngologists are trying to find a better way of determining the ideal post-surgery recovery time for vocal patients. In the meantime, however, artists are getting smarter about vocal care. Singers share maintenance tips with one another: Perri, for example, gave advice to Adele when the British superstar underwent surgery last fall, and Santigold recalls emailing with Bjork about proper vocal care while traveling. Perri recently joined the Voice Health Institute, a nonprofit founded in 2003 to evolve voice restoration, and united with artists like Steven Tyler, Julie Andrews and Lionel Richie on the organization's advisory board. The singer takes strict care of her voice following her surgery, and Imagine Dragons' Reynolds plans to take vocal lessons after he fully recovers "to further my education in proper warm-ups and the use of my vocals."

But the real key, Santigold explains, is for artists to know their bodies and set parameters before surgery even becomes a possibility. The singer, whose sophomore album "Master of My Make-Believe" led to heavy promotion and festival appearances upon its May release, says that she requires at least eight hours of sleep per night, drinks as much water as possible on the road and usually refuses to perform for three nights in a row. "It's almost like you're a machine, like, 'Do this, do that,'" she says of her hectic schedule. "It's really up to the artist to lay down the law."