While technically all surgeries are invasive, some surgeries are more invasive than others. Usually, the more invasive the surgery, the higher the risk of complications and the longer the postoperative recovery period. Surgeons have a lot to consider when they choose a particular approach for each patient. Some candidates need more invasive surgery but might not be good candidates, so a lot must be taken into consideration. This is often the case with spinal surgery. Although the surgery is medically necessary for the patient to manage his or her pain, it’s not usually a surgery that would be done in a life-threatening situation. This makes it possible for the surgeon to weigh the pros and cons of the different approaches.
The types of complications that may happen as the result of spinal surgery is one thing to consider, but comparing different types of surgeries and their complications is easier said than done. The patients vary too much from study to study for researchers to be able to draw general conclusions. As well, the type of surgery is affected by the surgeon and the operating room staff, as well as the facilities. The authors of this article felt that having an index that could grade the risks would make it easier for surgeons to identify who would benefit more from more invasive treatment and who should likely avoid it. To do this, they had to develop a quantitative (measurable) description of how invasive the procedures were.
To design the index, researchers used six criteria:
1- The anterior decompression score (ad), which looked at the number of vertebrae (bones in the spine) that needed to be removed, either partially or completely taken from the anterior (front) approach.
2- The anterior fusion score (af), which looked at the number of vertebrae that needed to be grafted (have a piece joined to them) for replacement or strengthening.
3- The anterior instrumentation score (ai), which took into account how many vertebrae needed hardware (screws, plates, etc).
4- The posterior decompression score (pd), which took into account how many vertebrae needed laminectomy or foraminotomy, pieces of bone removed or if the disc was removed using the posterior approach.
5- The posterior fusion score (pf), which looks at the number of vertebrae that were grafted in certain spots.
6- The posterior instrumentation score, which looks at the number of vertebrae that have hardware attached to certain spot.
If a surgery didn’t involve any of the above or only needed to be debrided (dead and damaged tissue removed) or irrigated, the invasiveness score was considered to be zero.
The researchers looked at 1745 patients who had had spinal surgery and their operating room logs and ended up with 1723 patients in all. Each patient was evaluated for one surgery. Among this group, 873 patient were actively monitored and 850 were in the passive surveillance group. There were 802 patients who participated in follow-up interview, 668 were from the active group.
The results showed that there was “a strong association with blood loss,” as much as 44 percent between the different levels of invasiveness. There wasn’t any connection between blood loss and the sex of the patients, their body mass index, smoking, or alcohol use. What did make a difference was the number of vertebral levels that were operated on, how long the surgeries were, the way the surgeon approached the surgery, and the type of surgery.
In all, the study authors concluded that there was an increase in blood loss of up to 11.5 percent and surgery time was lengthened by 12.8 minutes for each level up on the invasiveness index. This finding may be useful to match the right surgery to the right patient, limiting complications in the long run.