Pedicle Screw Placement in Pediatric and Adolescent Spinal Deformity Surgery: Does Tapping of the Pedicle Screw Tract Increase Safety?

Introduction: Since the development of pedicle screw fixation in the spine, safe placement has remained a crucial component in maximizing patient outcomes and mitigating pedicle screw-related complications. The purpose of this study is to investigate the utility of pedicle tapping in identifying pedicle breaches.

Methods: A pediatric spine surgery database was queried to identify a consecutive series of patients who underwent spinal deformity surgery utilizing pedicle screw fixation between May 2019 and October 2022. A "breached pedicle" was defined as a pedicle with intact walls after initial manual cannulation but found to have a breach upon probing after tapping 1 mm smaller than the planned screw diameter. The number of screws placed and breached was prospectively recorded, along with patient demographics and procedural data.

Results: There were 288 patients (68% female) with a mean age of 14.3 years (range: 3.7 to 23.3). Diagnoses included idiopathic (129), neuromuscular (76), syndromic (38), congenital (23), kyphosis (9), spondylopathy (12), and trauma (1). The mean upper and lower instrumented vertebrae were T3 and L3, respectively, with an average of 1.4 posterior column osteotomies (PCOs) (range: 0 to 8). Posterior spinal fusion and segmental instrumentation (PSFSI) was the most common procedure (254 cases, 88%). Of 4796 attempted screw placements, 20 (0.4%) pedicles were breached: medial (17), lateral (1), inferior (1), and inferolateral (1). Fourteen screws were abandoned, 3 redirected, and 3 replaced by hooks. T1 (14.3%) and T6 (1.2%) had the highest breach rates. No associations were found between breached pedicles and age ( P =0.099), sex ( P =0.795), or PCOs ( P >0.05). Congenital scoliosis had the highest breach rate at 1.6%.

Conclusion: A total of 4796 pedicle screws were placed, with 1 of every 250 (0.4%) of pedicle screw insertions (n=20) having "breached pedicles" identified only after tapping. The technical step of pedicle screw tapping potentially mitigated the chance of a misplaced pedicle screw. Surgeons need to assess the value of this information in their surgical workflow and risk assessment.

Level of evidence: Level III.