Division of Orthopaedic Surgery, University of Toronto, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
Department of Diagnostic Imaging, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, ON, M5G 1X8, Canada.
Spine Deform. 2024 May;12(3):739-746. doi: 10.1007/s43390-024-00830-1. Epub 2024 Feb 27.
Pedicle screws are the primary method of vertebral fixation in scoliosis surgery, but there are lingering concerns over potential malposition. The rates of pedicle screw malposition in pediatric spine surgery vary from 10% to 21%. Malpositioned screws can lead to potentially catastrophic neurological, vascular, and visceral complications. Pedicle screw positioning in patients with neuromuscular scoliosis is challenging due to a combination of large curves, complex pelvic anatomy, and osteopenia. This study aimed to determine the rate of pedicle screw malposition, associated complications, and subsequent revision from screws placed with the assistance of machine vision navigation technology in patients with neuromuscular scoliosis undergoing posterior instrumentation and fusion.
A retrospective analysis of the records of patients with neuromuscular scoliosis who underwent thoracolumbar pedicle screw insertion with the assistance of machine-vision image guidance navigation was performed. Screws were inserted by either a staff surgeon, orthopaedic fellow, or orthopaedic resident. Post-operative ultra-low dose CT scans were used to assess pedicle screw accuracy. The Gertzbein classification was used to grade any pedicle breaches (grade 0, no breach; grade 1, <2 mm; grade 2, 2-4 mm; grade 3, >4 mm). A screw was deemed accurate if no breach was identified (grade 0).
25 patients were included in the analysis, with a mean age of 13.6 years (range 11 to 18 years; 13/25 (52.0%) were female. The average pre-operative supine Cobb angle was 90.0 degrees (48-120 degrees). A total of 687 screws from 25 patients were analyzed (402 thoracic, 241 lumbosacral, 44 S2 alar-iliac (S2AI) screws). Surgical trainees (fellows and orthopaedic residents) inserted 46.6% (320/687) of screws with 98.8% (4/320) accuracy. The overall accuracy of pedicle screw insertion was 98.0% (Grade 0, no breach). All 13 breaches that occurred in the thoracic and lumbar screws were Grade 1. Of the 44 S2AI screws placed, one screw had a Grade 3 breach (2.3%) noted on intra-operative radiographs following rod placement and correction. This screw was subsequently revised. None of the breaches resulted in neuromonitoring changes, vessel, or visceral injuries.
Machine vision navigation technology combined with careful free-hand pedicle screw insertion techniques demonstrated high levels of pedicle screw insertion accuracy, even in patients with challenging anatomy.
椎弓根螺钉是脊柱侧凸手术中固定椎体的主要方法，但仍存在潜在定位不当的担忧。在儿童脊柱外科手术中，椎弓根螺钉的定位不当率为 10%至 21%。定位不当的螺钉可能导致潜在的灾难性神经、血管和内脏并发症。由于大曲线、复杂骨盆解剖结构和骨质疏松症的结合，神经肌肉性脊柱侧凸患者的椎弓根螺钉定位具有挑战性。本研究旨在确定在接受后路器械和融合术的神经肌肉性脊柱侧凸患者中，使用机器视觉导航技术辅助椎弓根螺钉定位的螺 钉错位率、相关并发症以及随后的螺钉修正率。
对接受机器视觉图像引导导航辅助下胸腰椎椎弓根螺钉插入术的神经肌肉性脊柱侧凸患者的病历进行回顾性分析。螺钉由主治医生、骨科住院医师或骨科住院医师插入。术后进行超低剂量 CT 扫描以评估椎弓根螺钉的准确性。使用 Gertzbein 分类对任何椎弓根破裂进行分级（0 级，无破裂；1 级，<2mm；2 级，2-4mm；3 级，>4mm）。如果未发现破裂（0 级），则认为螺钉定位准确。
共纳入 25 例患者进行分析，平均年龄 13.6 岁（11 至 18 岁；13/25（52.0%）为女性。术前仰卧 Cobb 角平均为 90.0 度（48-120 度）。共分析了 25 名患者的 687 枚螺钉（402 枚胸椎、241 枚腰椎、44 枚 S2 髂骨螺钉）。手术培训生（住院医师和骨科住院医师）插入了 46.6%（320/687）的螺钉，准确性为 98.8%（320/320）。椎弓根螺钉插入的总体准确性为 98.0%（0 级，无破裂）。所有发生在胸椎和腰椎螺钉的 13 个破裂均为 1 级。在放置和矫正棒后，术中放射照片发现 44 枚 S2AI 螺钉中的一枚螺钉有 3 级破裂（2.3%）。随后对该螺钉进行了修正。没有一个破裂导致神经监测变化、血管或内脏损伤。
即使在解剖结构具有挑战性的患者中，机器视觉导航技术与谨慎的徒手椎弓根螺钉插入技术相结合，也能实现高水平的椎弓根螺钉插入准确性。
