Adult Spinal Deformities: Can Patient-Specific Rods Change the Preoperative Planning into Clinical Reality? Feasibility Study and Preliminary Results about 77 Cases

Abstract

<jats:p>Surgical management of adult spinal deformities remains challenging, and one of the major goals is to restore sagittal alignment. Spinal rods used for posterior fixation are usually delivered straight and bended manually during surgery. This manual bending can be responsible for undercorrection of the deformity. In the last years, prebended patient-specific rods have been developed and might be a valuable tool in order to optimize surgical results. The objective is therefore to use the time between surgical decision and operative room in order to realize a precise surgical planning and obtain patient-specific rods. We describe here the planning process and our preliminary experience with patient-specific rods in the management of adult deformity about 77 cases. On the 77 cases, PSR were used without further modifications of the shape. Based on 3-month postoperative evaluation, a significant decrease of sagittal vertical axis (−41%, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>p</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.0001</mml:mn></mml:math>) and pelvic incidence-lumbar lordosis (−62%, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mi>p</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.0001</mml:mn></mml:math>) was reported. Pelvic tilt was not significantly corrected, except in patients with Parkinson’s disease. In this subgroup of patients, measurements revealed a significant correction of SVA and PI-LL (−53%, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>p</mml:mi><mml:mo>=</mml:mo><mml:mn>0.005</mml:mn></mml:math>, and −81%, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mi>p</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.0001</mml:mn></mml:math>, respectively) but also of PT (−23%, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M5"><mml:mi>p</mml:mi><mml:mo>&lt;</mml:mo><mml:mn>0.001</mml:mn></mml:math>). The use of PSR, in our experience, was feasible and provided satisfactory short-term results. It can be a valuable tool in the management of adult spinal deformities. Further studies will be needed in order to confirm these preliminary results.</jats:p>

Pre-Operative Planning in Complex Deformities and Use of Patient-Specific UNiD™ Instrumentation

“… 6 In a separate 3 month post-operative evaluation of outcomes of 77 patients, the authors found the planning and use of the rods provided significant improvement in SVA and PI-LL. 7 They again noted, as have previous studies, that PT was improved, but less predictable. They also reported on 86 patients with at least 1 year follow-up.…”

Patient-specific rods in adult spinal deformity: a systematic review

“…Prost and Pesenti later evaluated 77 patients at 3 months following ASD correction surgery involving PSRs, finding a similar improvement in SVA (mean 27.1 ± 8.6 mm, p < 0.0001), interestingly greater in patients with Parkinson’s disease (MD 53 mm, p < 0.005) [ 12 ]. Farah et al also presented data on 12 patients with Parkinson’s disease, reporting improvement at 1 year follow-up (MD 76.1 mm, P = 0.013) [ 13 ].…”

Emerging Technologies in the Treatment of Adult Spinal Deformity

“…74 A study examining 43 ASD cases using PSRs with no intraoperative adjustments to the prebent rods found improvements in SVA and PI-LL, confirming the clinical feasibility of their use. 14 Other studies have demonstrated strong and stable treatment effects at a 2-year follow-up in patients treated with PSRs, with particular improvements noted in SVA and PI-LL. 75 Two armed studies comparing PSRs to the current standard of care are lacking.…”

“…71,80 Lastly, exact knowledge of rod curvature preoperatively will allow further postoperative analysis and improved surgical planning research. 14,67…”

“…13 By implementing PSRs, we can expect to see better corrections for patients, lower rates of rod breakage, and decreased operative times. 14 Additionally, this allows for more precise and reproducible results as opposed to manual bending which presumably cannot be recreated accurately. As the future of ASD surgery continues to advance technologies, we can expect more successful surgeries, more accurate predictions, and fewer complications for patients.…”