BY KEITH ROACH, M.D.

Persistent lower back pain calls for neurosurgical intervention DEAR DR. ROACH: I’m a 70-year-old active dentist and pharmacist with chronic lower back pain. My MRI shows a compressed/extruded disc in contact with a specific nerve. It is extruded by 5 mm. I know that this is very common, and not all patients with compressed nerves are symptomatic. I have specifically located lower back pain and numbness in the muscles of my thigh, which has worsened to weakness.

Two intraspinal injections and daily stretching have helped control the pain, but muscle weakness persists. (I can stand from a squatting position but have difficulty standing from a seated position at times.) I am worried this might interfere with my activities. Am I living with the risk of permanent nerve injury? When should I consider surgery? — F.N.B., DDS ANSWER: You are right that this is a common problem and that most people with a herniated disc will get better with conservative management. Consertative management consists of rest (with exercise only as tolerated), as well as anti-inflammatory and pain medication, followed by physical therapy.

However, when a person develops weakness, it is time to get substantially more concerned. Severe or progressive weakness is one of the clearest indications for neurosurgical intervention, and you should follow up closely with your doctor because of the weakness. It can sometimes be hard to tell weakness that is due to nerve injury apart from weakness that is due to pain, but an experienced examiner is usually able to do so.

Persistent pain in a person with a disc compressing a nerve is an indication for a discussion about surgery with an expert, such as a neurosurgeon or an orthopedic surgeon who frequently perform these surgeries. Overall, people tend to get better with or without surgery, but results are faster with surgery.

There are a few cases where surgery is clearly indicated, but I usually refer my patients when they have severe, persistent pain and severe or progressive weakness, or when a person simply can’t do their daily activities. The decision to have surgery is always up to the patient in consultation with their surgeon, if the surgeon agrees that they are an appropriate surgical candidate.

DEAR DR. ROACH: What treatment options are available for dandruff that is hereditary? — A.L.

ANSWER: Seborrheic dermatitis is a common skin inflammation of the scalp. It does have a hereditary component, but the exact cause of the disease is unknown. A skin fungus called Malassezia may be part of the cause.

Generalists like me can treat mild disease, with the first-line treatment being antifungal shampoos such as selenium sulfide 2.5% over-the-counter or ketoconazole by prescription. These are applied for 3-5 minutes two or three times per week for four weeks or so. If this doesn’t do the job, topical steroids can be tried, but I usually have a patient see a dermatologist by then. Other conditions can cause scalp skin to flake off and lead to dandruff, or perhaps more potent agents should be used.

If the treatment is effective, then the shampoo can be used occasionally, commonly once or twice a week, to keep the condition under control.