Patients with the more rare form of MSK marked by chronic pain typically require pain management. Non-obstructing stones in MSK can be associated with significant and chronic pain even if they're not passing. It is not certain what causes this pain, but researchers have proposed that the small numerous stones seen in MSK may cause obstruction of the small tubules and collecting ducts in the kidney. This pain can be constant, can often be debilitating and treatment is challenging. Narcotic medication, even in large quantities, is sometimes not adequate. Some success with pain control has been reported using laser lithotripsy (called "ureteroscopic laser papillotomy").