The spine is made up of small bony segments called vertebrae. These vertebrae are categorised into cervical or neck vertebrae, thoracic (upper back), lumbar (lower back) and sacrum. A cylindrical bundle of nerve fibres called the spinal cord passes through the entire vertebral column and branches out to the various parts of our body.

Cushioning discs present between the vertebrae act as shock absorbers that redistribute the forces acting on your vertebrae when you walk, run, bend, or twist.

These intervertebral discs are made up of two types of cartilage: the inner pulpy cartilage known as nucleus pulposus which is surrounded by concentric layers of fibrous cartilage known as annulus fibrosis.

When this cartilage in the center of the disc protrudes through small tears in the hard-outer covering of the disc, the nerves passing through the spinal cord can become compressed or pinched, causing severe pain and deformity. This is known as disc herniation.

Minimally Invasive Microdiscectomy or METRx Discectomy uses microscopic or endoscopic techniques to access and remove this herniated disc and relieve pressure on the compressed nerves.

Disease Overview

As you age, gradual wear and tear occurs to the spinal discs causing them to lose water content. This makes them more susceptible to rupturing or tearing. Any heavy lifting or minor trauma can cause disc herniation. Most disc herniation occurs in the lumbar spine, causing debilitating pain in your buttocks, thigh, and calf areas. Herniated discs in the cervical spine cause pain in the shoulder and arm. Other symptoms associated with a herniated disc include numbness and tingling or weakness in the region served by the pinched nerve.

Symptoms of disc herniation can be alleviated by surgically releasing the herniated disc through a surgical procedure called a minimally invasive microdiscectomy.


METRx is indicated most commonly for Disc herniation. However, it can also be used for

  • Laminotomy: partial excision of the thin bony plate of the vertebra
  • Medial facetectomy: removal of the facet joint that guides the movement of spinal bones
  • Foraminotomy: expanding a foramina or bony opening to allow clearance of nerves
  • Nerve root retraction

Surgical procedure

Minimally invasive microdiscectomy or METRx discectomy is usually performed on an outpatient basis under spinal or general anesthesia. You will be lying on your stomach during the procedure.

Your surgeon will use live-action X-ray called fluoroscopy to accurately visualise your spine and locate your herniated disc. Under the guidance of the fluoroscope, your surgeon will insert a guide wire through the skin and muscles in your back to the diseased area. A half-inch skin incision is made over the area to be treated and dilators are inserted sequentially.  The dilators create a tunnel leading to the affected disc by splitting the back muscles instead of cutting them. The guide wire is then removed.  Retractors are used to hold the tunnel open, and a microscope and special surgical instruments are inserted. Viewing through the microscope, your surgeon trims and removes the diseased disc using special cutting instruments. After completion, the dilators are removed and the muscle fibers joined back together. A small strip of adhesive bandage is applied over the incision site at the completion of the procedure.

Post-Operative Care

You will be prescribed pain medications to relieve immediate postoperative pain. Cold packs may be applied as instructed for pain relief. Your doctor will educate you on gentle stretching, strengthening, and conditioning exercises to be performed during the postoperative period.

University of Leeds British Orthopaedic Association Royal College of Surgeons Swansea University NHS Royal College of Surgeons of Edinburgh