Application of three-dimensional model in the management of irreducible atlanto-axial dislocation

Abstract

Objective:The aim of this study was to describe the application of the rapid prototyping (RP) life-size 3-dimensional model used to improve accuracy of screw insertion in irreducible atlanto-axial dislocation (IAD).

Methods: The study included 10 patients with IAD. All patients were assessed using the Japanese Orthopedic Association (JOA) score. Radiographs, MRI and CT were conducted during the preoperative and postoperative procedure. A 3D RP model was created for each patient. The model was used to obtain detailed information of each pedicle and used as an intraoperative reference. Assisted by the model, transoral atlanto-axial reduction plate fixation was performed in each case.

Results: The average operation time was 145 (range: 90 to 180) minutes and average blood loss was 120 (range: 60 to 250) ml. JOA scores improved after surgery. All 40 transoral pedicle/lateral mass screws were placed without serious complications or internal fixation failure. Postoperative radiographs and CT scan showed 38 transoral pedicle/lateral mass screws located in the pedicle tracts. Satisfactory reduction was achieved in 95% of screws. Two screws perforated the lateral wall of the C2 pedicles in an extremely narrow pedicle case. No neurologic sequelae or vertebral artery injury were detected.

Conclusion: The RP technique is effective and reliable in achieving an accurate and safe screw insertion during IAD surgery, especially in anatomically abnormal cases.

Keywords

• Anatomic model
• atlanto-axial instability
• atlanto-axial joint
• rapid prototyping

Redükte edilemeyen atlantoaksiyel çıkık tedavisinde üç boyutlu model uygulaması

Abstract

Amaç:Bu çalışmanın amacı, redükte edilemeyen atlantoaksiyel çıkık tedavisinde vida yerleştirilmesi uygulamasının doğruluğunu geliştirmek için kullanılan gerçek boyutlu hızlı prototipleme (HP) 3-boyutlu model uygulamasını tarif etmekti.

Çalışma planı: Çalışmaya redükte edilemeyen atlantoaksiyel çıkık bulunan 10 hasta dahil edildi. Tüm hastalar Japon Ortopedik Derneği (Japanese Orthopedic Association, JOA) skoru kullanılarak değerlendirildi. Cerrahi işlem sırasında ve sonrasında grafiler, MRG ve BT çekildi. Her hasta için 3 boyutlu bir HP modeli yaratıldı. Model, her pedikül hakkında detaylı bilgi elde etmek amacıyla ve ameliyat sırasında bir referans olarak kullanıldı. Model yardımıyla, tüm olgularda transoral atlantoaksiyel redüksiyon plakası ile tespit yapıldı.

Bulgular: Ortalama operasyon süresi 145 (dağılım: 90-180) dakika ve ortalama kan kaybı 120 (dağılım: 60-250) ml idi. Cerrahi sonrası JOA skorlarının daha iyi olduğu görüldü. Kırk transoral pedikül/lateral mass vidasının tamamı ciddi bir komplikasyon veya internal tespit yetmezliği gelişmeden yerleştirildi. Ameliyat sonrası grafiler ve BT taraması, 38 transoral pedikül/lateral mass vidasının pedikül yollarında bulunduğunu teyit etti. Vidaların %95’inde tatmin edici bir redüksiyon elde edildi. İki vida son derece dar bir pedikül vakasında C2 pedikülünün yan duvarını deldi. Hastanın takibinde hiçbir nörolojik sekel veya vertebral arter yaralanmasına rastlanmadı.

Çıkarımlar: Hızlı prototipleme redükte edilemeyen atlantoaksiyel çıkık ameliyatı sırasında, özellikle anormal anatomik olgularda, doğru ve güvenli vida yerleştirilmesi açısından etkili ve güvenilir bir tekniktir.

Keywords

• Anatomik model; atlantoaksiyel instabilite; atlantoaksiyel eklem; hızlı prototipleme

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