Biportal Endoscopic Spine Surgery (UBE): Discs to TLIF

Biportal endoscopic spine surgery, often called unilateral biportal endoscopy (UBE), works through two small channels on the same side of the spine. One channel carries the endoscope and the other carries the instruments, so the surgeon operates while watching a magnified image on a monitor, much as in knee arthroscopy.

Dr. Puneet Girdhar, Chairman - Max Institute of Robotics and Minimal Invasive Spine Surgery - Ortho Spine, MIS & Robotic Spine Surgery, BLK-Max Super Speciality Hospital, New Delhi, India, uses it through incisions of under 5 mm for large disc herniations, lumbar canal stenosis, multilevel decompression in elderly patients and, more recently, transforaminal lumbar interbody fusion (TLIF).

What biportal endoscopic spine surgery is and how it differs from a tube

In tubular microscopic surgery, a tube of 16 to 20 mm is passed through the muscle and the surgeon works down it under an operating microscope. Biportal endoscopy replaces the tube with two separate portals, each under 5 mm, placed on the same side of the spine. The endoscope sits in one, fitted with a 0 degree or a 30 degree lens, and normal surgical instruments pass through the other.

Dr. Girdhar mentioned two tools. The first is the underwater drill: bone is removed while irrigation fluid runs through the field, which keeps the view clear and carries debris away. The second is radiofrequency ablation, used to burn away (ablate) soft tissue as the surgeon works. With these, a full decompression can be performed, including removal of the ligamentum flavum (the thick ligament at the back of the spinal canal), through two small cuts.

Dr. Girdhar describes the gain in plain terms. The surgical footprint has fallen from a couple of centimetres to a few millimetres, with less collateral damage and the least possible muscle injury. He regards the technique as transformational for his centre, and fellows travel to train on it.

The path from open surgery to the endoscope

Dr. Girdhar's unit reached the endoscope in stages. He has performed microscopic tubular surgery for 15 to 16 years. For the last year and a half, he has moved discectomy, decompression and TLIF for spondylolisthesis to biportal endoscopy. He says the endoscope gives an extra edge in the surgical footprint left for the patient.

Large and migrated disc herniations

All of his disc herniations, and especially the large ones that have migrated down the canal, are now done by biportal endoscopy, which is a large part of his surgical volume. The nerve root is decompressed and the fragment removed through the two small cuts.

One case he presented shows the effect. A woman had been limping for about six months with a large L5-S1 herniation. The final weeks were the worst: she could not sit and had numbness in the foot. The operation was biportal endoscopic discectomy through two small cuts, with the camera in one portal and standard instruments in the other. She was discharged within a week and returned to her work.

Lumbar canal stenosis: decompression and flavectomy

Lumbar canal stenosis is a narrowing of the spinal canal that compresses the nerves, through some combination of thickened ligament, enlarged facet joints and bulging disc. In Dr. Girdhar's unit, discectomy, decompression and removal of the ligamentum flavum (flavectomy) for stenosis are all done endoscopically.

Stenosis without instability is treated by freeing the nerves. Fusion is considered when there is instability, such as a vertebra that has slipped (spondylolisthesis), which is why spondylolisthesis with stenosis is treated differently from stenosis alone.

Multilevel decompression in patients over 80

Biportal endoscopy also suits multilevel stenosis in patients over 80. In some of them the degenerated segments have stiffened on their own, which Dr. Girdhar calls auto-stabilisation. These patients do not have significant back pain. Their problem is claudication, pain or heaviness in the legs that shortens the distance they can walk. They do not need fixation or facetectomy (removal of the facet joints); they need decompression.

For these patients Dr. Girdhar makes three or four cuts of 5 mm instead of large incisions. He removes the ligamentum flavum from the medial aspect of the facets on each side, using radiofrequency ablation and micro-drilling, and decompresses three levels this way. Blood loss is under 50 mL, patients walk freely the next day, and they go home. The aim is a better walking distance, with a good decompression and without fixation.

Endoscopic TLIF: fusion through the endoscope

TLIF is a fusion operation. The surgeon reaches the disc from one side through the foramen (the exit gap for the nerve) after removing part of the facet joint, removes the disc, places a cage in the disc space to restore height and promote fusion, and fixes the segment with screws.

Dr. Girdhar did open TLIF until 2012. Since then, his one-, two- and three-level patients have been treated with a microscopic, tubular technique: the cage and screws go in through two cuts, each shorter than two inches. A post-operative image on his slide showed the result in a patient who had a laminotomy at another centre two years earlier. That patient presented with spondylolisthesis and severe stenosis, with claudication and radiculopathy (pain along the course of a nerve), and needed a TLIF.

The newest step is full endoscopic TLIF. His team has performed a few of these for patients with lumbar canal stenosis and degenerative facet joint disease, and he describes them as a further reduction in footprint. On screen, the intraoperative radiograph shows the cage in position while the endoscopic view shows it advancing into the disc space. In his assessment, the end plates (the surfaces of the vertebrae on either side of the disc) can be prepared excellently, all the way deep to the region close to the anterior longitudinal ligament, with a clear view of the end plates and cartilage.

What small incisions mean for the patient

Dr. Girdhar summarises the patient-level benefit as small incisions, preservation of muscle, less pain and faster recovery. Across his minimally invasive work, endoscopic surgery and microdiscectomy usually mean a hospital stay of one to two days, and minimally invasive fusions three to four days at most. Most of his primary patients walk the day after surgery. In the Q&A he added that the minimally invasive, targeted approach gives a magnified view of the nerves and ligaments, whereas open surgery always carries the risk of a dural tear (a tear in the membrane around the nerves) and nerve injury, and that the possibility of injury has gone down with the endoscopic approach.

Most of his one- to three-level fusions are still done through a tube, and the unit has performed a few full endoscopic TLIFs as the newer step. The decision to operate at all rests on the indications discussed in Indications for Spine Surgery: A Complete Guide.

Connected reading

This article describes the technique. The wider picture of the unit, its safety record and its limits is in Endoscopic and Robotic Spine Surgery: A Complete Guide. Robotic screw placement, which the same unit uses for longer fusions and revision surgery, is covered in Robotic Spine Surgery for Revision and Complex Cases.

An earlier Jivo Masterclass by Dr. Girdhar covered Endoscopic Spine Surgery for Slipped Disc and Stenosis. The questions put to him at this session are in the Live Discussion, and his profile is on the doctor page. For budgeting, see the guides to microdiscectomy, TLIF and spinal decompression and fixation.