Etemadifar Mohammadreza, Jamalaldini Mohammadhossein
Department of Orthopedic and Spine Surgery, Al-Zahra Hospital, Isfahan University of Medical Sciences, Isfahan, Iran.
Adv Biomed Res. 2017 Mar 1;6:19. doi: 10.4103/2277-9175.201331. eCollection 2017.
Pedicle screw instrumentation has many advantages for correction of adolescent idiopathic scoliosis (AIS) deformity including better correction and fewer late complications. On the other hand, screw insertion in AIS is challenging. Intraoperative fluoroscopy or navigation techniques are expensive, time-consuming, and exposed to high radiation. Free-hand technique relies on the surgeon's experience and locating the pedicle entry point with anatomical landmarks. There are few studies that evaluated pedicle screw position accuracy with postoperative multi-slice computed tomography scan.
We prospectively considered 38 consecutive AIS cases, who underwent corrective surgery with all pedicle screw technique. All the screws were inserted with free-hand technique using anatomic landmarks as a guide for an entry site. We divided pedicle penetration in medial, lateral, inferior, superior, and anterior vertebral body as Grades 0-4, that Grade 0 is fully contained within the pedicle, Grade 1 (<2 mm), Grade 2 (2.1-4 mm), Grade 3 (4.1-6 mm), and Grade 4 (>6 mm).
A total of 720 screws were inserted, of which 623 screws (86.5%) were perfect and 97 screws (13.5%) were misplaced. Of those which were misplaced, 39 screws (40.2%) were medial and 58 (59.8%) were lateral, which shows that the prevalence of lateral misplacement was more in comparison to medial misplacement. However, in all misplaced cases, the deviation of the screw was <2 mm (Grade 1). There was no misplacement in the inferior and superior.
Pedicle screw insertion in AIS with the free-hand technique is a safe and reliable method.
椎弓根螺钉内固定术在矫正青少年特发性脊柱侧凸（AIS）畸形方面具有许多优势，包括更好的矫正效果和更少的晚期并发症。另一方面，在AIS患者中插入螺钉具有挑战性。术中透视或导航技术昂贵、耗时且暴露于高辐射。徒手技术依赖于外科医生的经验，并通过解剖标志来确定椎弓根入口点。很少有研究通过术后多层计算机断层扫描来评估椎弓根螺钉的位置准确性。
我们前瞻性地纳入了38例连续的AIS病例，这些病例均接受了全椎弓根螺钉技术的矫正手术。所有螺钉均采用徒手技术插入，以解剖标志作为入口点的引导。我们将椎弓根穿破椎体分为内侧、外侧、下方、上方和前方5个等级，0级为完全位于椎弓根内，1级（<2 mm），2级（2.1 - 4 mm），3级（4.1 - 6 mm），4级（>6 mm）。
共插入720枚螺钉，其中623枚（86.5%）位置理想，97枚（13.5%）位置不当。在位置不当的螺钉中，39枚（40.2%）为内侧穿破，58枚（59.8%）为外侧穿破，这表明外侧穿破的发生率高于内侧穿破。然而，在所有位置不当的病例中，螺钉的偏差均<2 mm（1级）。下方和上方没有穿破情况。
徒手技术在AIS患者中插入椎弓根螺钉是一种安全可靠的方法。
