Patients with certain types of slow growing (indolent) lymphomas, including the most common sub-type, follicular lymphoma, require a bone marrow examination for staging of their lymphoma. This provides prognostic information and can be important for planning treatment. However, despite the use of local anaesthetic, and in some cases sedation, bone marrow examinations can cause pain and discomfort to patients. Complications are rare but include risk of bleeding, infection and even nerve damage.