Idiopathic Scoliosis – The Importance of Super Accurate Placement of Pedicle Screws
According to the National Institute of Health publications, as assessed by computed tomography overall pedicle perforation rates for perforations >0 and >2 mm ranged from 6.4% to 65.0% and 3.7% to 29.9%, respectively. NIH Article
The accurate placement of pedicle screws is, of course, of paramount importance to a scoliosis patient as a misplaced screw could result in the loss of the use of a limb, incontinence, loss of sexual function, or becoming a paraplegic. And as the cited in the article misplaced pedicle screws happen all too often.
Of course, the wide variation in results depend many factors. But the most obvious factors are:
1. The skill and experience of the surgeon
2. The technique the surgeon uses
3. The complexity of the case
As with Prof. Dr. Bertagnoli with over 30 years of spine surgery and very high success rates his experience and skill are self-evident. Yet some new technology can offers benefits.
Super accurate placement of pedicle screws has two major benefits, the aforementioned lack of misplacement, but also the placement of screws in cortical portion of vertebral body (the most dense portion of the bone), making it stronger and less likely to loosen.
So the patient may ask, “How is super accurate placement accomplished?” While there are several very expensive machines with use high doses of radiation that help guide pedicle screw placement, there are low-cost, low-radiation methods.
Low-radiation, low-cost super accurate placement is possible using the following steps
1. Low-radiation CT
2. Recreation of the patient’s spine using the data from the CT for 3D printing.
3. Creation of individualized drill guides for each vertebra, which are attached to the vertebra during the operation.
4. After drilling of the pilot hole using the guides, an X-ray check of the hole with a plug before implanting the screw.
5. Placement of previously sized screws.