DEAR DR. ROACH: I am a 77-year-old female who recently had an abdominal and pelvic cat scan to rule out diverticulitis, and it came back showing a left staghorn calculus. What causes this calculus, and is there treatment other than surgery?

• Anon.

ANSWER: A “staghorn” calculus is a kidney stone that has grown to fill up a large part of the collecting system of the kidney.

Antibiotics alone cannot cure a struvite stone. Treatment used to mean surgery, but some people have an anatomy that is favorable to lithotripsy (sound waves to break up the stone) and percutaneous nephrolithotomy. The latter uses a surgical instrument through the back and into the kidney, where the stone can be removed a piece at a time. The two treatments are often used in combination.

A urologist is absolutely essential as only they have the expertise to recommend the right treatment for a given person’s anatomy.

DEAR DR. ROACH: I’m an 84-year-old woman who has, for years, had trouble falling asleep. Lately I also wake up in the middle of the night and seem to be unable to go back to sleep at times. I have been taking melatonin spray and Ashwagandha gummies with so-so results. I was wondering about your take on CBD for insomnia and also whether the gummies I’m taking are safe.

• R.D.

ANSWER: Cognitive behavioral therapy for insomnia is the preferred therapy for chronic insomnia in people for whom it is available. Melatonin is generally safe, and although it does not work for everyone, I do not object to a trial. Though, I do recommend smaller doses than what is typically available, with 1 mg being a good dose to start at.

Ashwagandha is a medicinal herb commonly used in Ayurvedic medicine, and many people use it in this country for sleep. It is also generally safe, although there are rare reports of liver injury associated with its use. It may slightly increase thyroid hormone levels, so it should be used in caution in people with thyroid issues.

Cannabidiol is a component of the cannabis plant. It does not have psychoactive properties, but many people report a reduction in anxiety, which might help with sleep. The main concern I have with buying CBD is that many of the products sold as CBD also have undisclosed THC. Buying CBD with a third-party lab analysis is the best way of making sure that you are getting what you want without what you don’t want.