Even simple spinal surgeries can result in serious problems when infection occurs. Despite sterile techniques, any open incision leaves the patient at increased risk of wound infection. The use of minimally invasive spinal surgery (MISS) may be changing the picture.
In this study, surgeons found that the rate of postoperative surgical site infections (SSI) was significantly less with minimally invasive spinal surgery (MISS) compared with the more traditional open approach. In fact, out of the 1,338 minimally invasive spinal surgeries (MISS) in this study, there was a less than one per cent chance of SSI — that’s 10 times less than for open incision procedures. In dollars and cents, the reduced hospital time, decreased use of antibiotics, and avoidance of further surgery can amount to a drastic savings in health care costs.
The average age of the patients in this study was 55 years old. Patients ranged in age from 18 to 97 years old. Most of them had low back pain from degenerative spine disease (e.g., spinal stenosis, degenerative disc disease, arthritis). The most common procedure performed was a simple spinal decompression. In this operation, the surgeon removes part of the vertebral bone called the lamina. By cutting some of the bone out, pressure is removed from the spinal cord or spinal nerve roots. Other surgeries performed included spinal fusion, tumor removal, and shunt insertions. A shunt is a thin, plastic tube used to drain excess cerebrospinal fluid (CSF) from around the brain and/or spinal cord.
For this study, MISS was defined as any spinal surgery done using a tubular retractor type system. A very tiny incision is made in the skin. A special tubular instrument is inserted through the incision down to the bone. Surgical tools are then passed through the tube down to the surgical site. A tiny TV camera on the end of the system allows the surgeon to see the area.
The few infections that occurred were the result of either strep or staph bacteria. Patients presented with skin changes, fever, back pain, or urinary tract infection. All were treated successfully with antibiotics. Even though all patients are given antibiotics to prevent these kinds of problems, SSIs after spine surgery do occur. Known patient risk factors for SSIs include diabetes, incontinence, and obesity. Risk factors related to the surgery include posterior approach and poor timing or inappropriate dosing of the preoperative antibiotics.
The authors propose four reasons why MISS results in such improved infection rates: 1) decreased exposure of deep tissues, 2) the surgical tube blocks transport of bacteria, 3) small incisions close up and heal faster than large incisions that can pull apart more easily and 4) smaller incisions means less chance of wound drainage or blood pooling where infection can form.
In summary, the combination of sterile technique, preoperative antibiotics, and MISS has reduced the rate of postoperative infection linked with spinal surgery. Rates in this study were compared with rates reported in other published studies. There is a need for further research to verify these findings.