Minimally Invasive Surgery Lumbar
Traditionally whenever we need to operate on spine through open procedure, we have to take a longer incision extending above and below the area of interest. The muscles are then shaved off the bones, to reach the lamina which may cause injury to the blood supply of the muscle fibres, resulting into permanent damage of the muscle and pain. Another reason for the damage to the fibres can be attributed to the continuous retraction of the muscle fibres for longer time, which may also impair its blood supply. Unfortunately, it increases the intraoperative blood loss and the risk of infection,
Sometimes while exposing the surgical site elevating the muscles, the facets can get damaged resulting into more spine pain.
Just to alleviate these side effects, minimally invasive spine surgery (MIS) for the lumbar spine has been developed.
- In MIS procedure, we use significantly smaller incisions. Later, we pass serial dialators to spread the muscle fibres and finally we introduce a tubular retractor system with an arm to reach the point of interest. So, in this we are not shaving of the muscles, the adjacent joints are not exposed and the injury to the facetal joints are less likely, blood loss is less with minimal irritation to the muscle fibres.
- Through the tubular retractor, the decompression procedure can be achieved, similar to an open procedure. Once the procedure is done, the tubular retractor is removed, and the muscle fibres fall into place.
1). Guide wire is introduced at the point of interest under fluoroscopic guidance.
2). The guide wire is inserted through the incision and directed toward the appropriate land mark. The first dilator is placed over the guide wire and the guide wire is removed
3). Use the initial dilator to palpate the lamina in both the coronal and sagittal planes. The tip of the dilator is used to sweep the para-spinal musculature off the laminar edge. This maneuver affirms coronal placement and expedites soft tissue removal
4). Dilators are sequentially placed over each other until the desired diameter is reached
5). The Flexible Arm is attached to the Tubular Retractor and the ipsilateral bed rail. The Tubular Retractor is placed over the sequential dilators, docking on the lamina. It is important to always apply downward pressure while adjusting flexible arm.
6). Drilling and decompression is done.
Open versus MIS
Less pain, less disruption of tissues, less blood loss, early ambulation, smaller scar, less infection rate, less chances of instability and faster recovery.
Different procedures can be done by MIS
- Decompression procedure (laminectomy/ discectomy): Most commonly MIS is done for these procedures. In this we decompress the hypertrophied ligaments, extruded disc, synovial cyst or osteophytes (bone spur).
Fusion Procedures: (Transforaminal lumbar interbody fusion TLIF): In this we drill out more bone then required in decompression and remove the facet joints as well. Then after removal of the disc, we put a spacer inside the disc space so that it does not collapse and is secured with the percutaneous pedicle screws and rods. This is usually done in spondylolisthesis patients, where the two adjacent vertebrae slip over the other
c). Tumor Resection Surgery: In this a bigger tube with 22 millimeter retractor system is used to remove the tumor and fusion can be avoided.
What is not MIS:
For anything to be MIS, the use of tubular retractor system is a must. This involves a smaller incision, a muscle fibers are not shaved resulting in lesser muscle damage and lesser chances of injury to the facetal joints. Thus, lesser complication rates.
- Some surgeons use a small incision, but does not use tubular retractors. They erase the muscles from the bone resulting into muscle damage and facetal joint disruption. This is not MIS.
- Anterior and lateral approaches which are used for spinal fusion and artificial disc placement are not MIS. These procedures might avoid damaging the back muscles, but there is lot of blood loss and injury to the major blood vessels, the abdominal organ injury can happen and the anterior spinal muscles are still injured.
- Nowadays, robotic (MAZOR) procedures for the mid and lower back are in trend. It is used along with MIS to do the procedures. Only use of robot does not make a procedure minimally invasive. There are many instances, where there is injury to the major vessel or nerve using robot due to errors in technology.
- Stem cell treatment is not a minimally invasive surgery. The results are not effective and still it is not FDA approved.
- Laser in minimally invasive spine surgery are used, but comparative results suggest that the rate of re-exploration is more in such patients is more than the traditional MIS procedure.