Reconstruction of Thoracic Spine Using a Personalized 3D-Printed Vertebral Body in Adolescent with T9 Primary Bone Tumor.

BACKGROUND: Neurosurgery and spine surgery have the potential to benefit from the use of 3-dimensional printing (3DP) technology due to complex anatomic considerations and the delicate nature of surrounding structures. We report a procedure that uses a 3D-printed titanium T9 vertebral body implant post T9 vertebrectomy for a primary bone tumor. CASE DESCRIPTION: A 14-year-old female presented with progressive kyphoscoliosis and a pathologic fracture of the T9 vertebra with sagittal and coronal deformity due to a destructive primary bone tumor. Surgical resection and reconstruction was performed in combination with a 3D-printed, patient-specific implant. Custom design features included porous titanium end plates, corrective angulation of the implant to restore sagittal balance, and pedicle screw holes in the 3D implant to assist with insertion of the device. In addition, attachment of the anterior column construct to the posterior pedicle screw construct was possible due to the customized features of the patient-specific implant. CONCLUSIONS: An advantage of 3DP is the ability to manufacture patient-specific implants, as in the current case example. Additionally, the use of 3DP has been able to reduce operative time significantly. Surgical procedures can be preplanned using 3DP patient-specific models. Surgeons can train before performing complex procedures, which enhances their presurgical planning in order to maximize patient outcomes. When considering implants and prostheses, the use of 3DP allows a superior anatomic fit for the patient, with the potential to improve restoration of anatomy.

Range of motion, sacral screw and rod strain in long posterior spinal constructs: a biomechanical comparison between S2 alar iliac screws with traditional fixation strategies.

BACKGROUND: S1 screw failure and L5/S1 non-union are issues with long fusions to S1. Improved construct stiffness and S1 screw offloading can help avoid this. S2AI screws have shown to provide similar stiffness to iliac screws when added to L3-S1 constructs. We sought to examine and compare the biomechanical effects on an L2-S1 pedicle screw construct of adding S2AI screws, AxiaLIF, L5-S1 interbody support via transforaminal lumbar interbody fusion (TLIF), and to examine the effect of the addition of cross connectors to each of these constructs. METHODS: Two S1 screws and one rod with strain gauges (at L5/S1) were used in L2-S1 screw-rod constructs in 7 L1-pelvis specimens (two with low BMD). ROM, S1 screw and rod strain were assessed using a pure-moment flexibility testing protocol. Specimens were tested intact, and then in five instrumentation states consisting of: (I) Pedicle screws (PS) L2-S1; (II) PS + S2AI screws; (III) PS + TLIF L5/S1; (IV) PS + AxiaLIF L5/S1; (V) PS + S2AI + AxiaLIF L5/S1. The five instrumentation conditions were also tested with crosslinks at L2/3 and S1/2. Tests were conducted in flexion-extension, lateral bending and axial torsion with no compressive preload. RESULTS: S2A1 produces reduced S1 screw strain for flexion-extension, lateral bending and axial torsion, as well as reduced rod strain in lateral bending and axial torsion in comparison to AxiaLIF and interbody instrumentation, at the expense of increased rod flexion-extension strain. Cross-connectors may have a role in further reduction of S1 screw and rod strain. CONCLUSIONS: From a biomechanical standpoint, the use of the S2AI technique is at least equivalent to traditional iliac screws, but offers lower prominence and ease of assembly compared to conventional sacroiliac stabilization.

Spine surgery in Nepal: the 2015 earthquake.

At noon on Saturday, 25 April 2015, a 7.8 magnitude earthquake struck Nepal. It was centered in the Himalaya northwest of Kathmandu, the capital of over 1 million people. The violent tremors were felt as far away as New Delhi, India 1,000 km from the epicenter, but the worst of its destructive force was experienced in the heavily populated Kathmandu valley and in the remote mountainous villages of the Himalaya. Ancient temples crumbled; poorly constructed buildings collapsed; men, women, and children were trapped and injured, sometimes fatally. Avalanches killed mountain climbers, Sherpa guides, and porters at Everest base camp (EBC). The death toll to date exceeds 8,600 with as many as 20,000 injured. Spinal Health International (SHI), a nonprofit volunteer organization, has been active in Nepal in past years and responded to requests by Nepali spine surgeons for assistance with traumatic spine injury victims following the earthquake. SHI volunteers were present during the 2(nd) major earthquake of magnitude 7.3 on 12 May 2015. Past and current experiences in Nepal will be presented.