Laminotomy and laminectomy are two surgeries to relieve pressure on the spinal cord. They make the opening in the spine (spinal canal) larger. As you get older or if you have an injury, the opening for the spine gets smaller. This condition is called stenosis.
During a laminectomy, the doctor removes pieces of the bony covering (the lamina) and other tissues that are squeezing the spinal cord and nerves. A laminotomy removes less of the bony covering. Both surgeries make the opening for the spinal cord and nerves larger. This takes pressure off the nerves.