Screenshots of the app on a demonstration case. Radiographs: public domain, Wikimedia Commons. The bending films of this case are made up.
One tool for the whole work-up of a spinal deformity: measure it on the films, read its sagittal shape against published norms, and rehearse the fusion on a 3D model that moves only as far as the patient's own spine did. A preview, never a forecast.
Open a study straight from the PACS export. Only the image and a short white list of tags (sex, age in years, study date) enter the case; name, record number and every other tag are left behind. Full 16-bit window and level.
Cobb angles, free angles, point-to-point distances and distances between vertical or horizontal parallels for leg length, shoulder height and coronal balance. Scale comes from the DICOM header or from an object of known size.
Mark the femoral heads and a few endplates on the lateral film: pelvic incidence, tilt and slope, lordosis L1–S1 and L4–S1, kyphosis, PI−LL, T1 pelvic angle, global tilt and SVA, drawn on the radiograph.
The shape the pelvic incidence calls for against the shape the patient stands in: classical, anteverted, false and kyphotic types, apex and inflection of the lordosis, how it is shared between its arcs, and the GAP proportion score.
Cobb angles between the most tilted vertebrae and the Lenke classification as published: structural curves by bending residual or regional kyphosis, lumbar modifier and sagittal thoracic modifier.
Every motion segment from T1 to S1 gets its own range from the patient's standing and side-bending films: that is its mobility reserve. The free segments may spend it to rebalance the trunk, and the simulator tells how much of it a plan uses up. No population averages, and no mobility that was not measured.
Fix any combination of segments, in situ, at the bending position or at a chosen correction; add asymmetric interbody supports or a shoe lift; and watch the free segments rebalance on an interactive 3D model, with Cobb angles, T1 balance and the tilt of the end vertebrae changing as you go. Compare the options side by side.
The case library lives in a folder on your own disk, or in your browser. Search it by name, record number, hospital or date. Nothing about your patients is stored on our servers.
A PDF with every measurement and figure, radiographs in negative and models on white to spare ink. Send a case to a colleague by email or messaging with the patient's identity stripped out.
PSO and SPO/Ponte osteotomies at one or several discs, interbody and asymmetric cages, resections with their implant, slips, the femur stood up and the pelvis leveled, tried on the radiograph itself, frontal or lateral: the film is cut and moved as planned, and the parameters change with it.
Photograph the screen of the image intensifier shot by shot with your phone, or bring the shots in as DICOM straight from the C-arm, and join them into one long frontal or lateral film, to check on the table what was planned at the desk.
Screenshots of the app on a demonstration case. Radiographs: public domain, Wikimedia Commons. The bending films of this case are made up.
Four steps from the patient's radiographs to a plan you can compare, print and share.
Drop a DICOM study or plain images: standing frontal and lateral films, plus side-bending films if you plan to simulate. Identity is stripped on the way in.
Measure on the films: Cobb and free angles, distances, spinopelvic parameters and the sagittal shape. Then mark T1, S1 and five vertebrae in between on the frontal and the lateral film, side by side: the 3D model is built from those marks, and laid on each bending film in turn.
Choose the fused segments and their position, then compare scenarios: balance, Cobb angles, the tilt of the end vertebrae and the share of the mobility reserve each one uses.
Keep the case in your own library, print the PDF report for the chart, or send an anonymous copy to a colleague.
ScolioSim was created by Dr. Diego Ferrández Sempere, a spine surgeon with 20+ years of experience in complex spine surgery. Born from the need to measure a deformity properly and rehearse different fusion levels before entering the operating room, and to do what no software had done until now: reproduce how the segments that are still flexible behave once part of the spine is fixed.
ScolioSim is a browser-based tool for spine surgeons with two parts. The first works on the radiographs: Cobb and free angles, calibrated distances, spinopelvic parameters, the Roussouly analysis of the sagittal shape and the Lenke classification, and a surgical plan drawn on the film itself, which is cut and moved along osteotomies, cages, resections and slips. The second is a 3D simulator: a vertebral model is fitted on the patient's standing and side-bending films, the surgeon chooses which motion segments to fix, and the model shows how the remaining free segments rebalance the trunk.
No. ScolioSim does not forecast results and gives no probability of anything. The simulator only replays the mobility each segment showed on the patient's own bending films under the constraints of the chosen fusion. How an operated spine settles is a biomechanical problem that nobody can yet solve for a given patient, so ScolioSim offers several mathematical approaches to it, to be observed: shoulders leveled first or the head centered first, every free segment spending the same share of its mobility reserve, or each in turn as it lies further from the fixation. The intent is observational: with the before and the after of each operation, a surgeon can set the real result beside those variants, and that accumulated experience may one day let us say more closely how an operated spine will behave. For now we are only playing; but playing is another way of learning.
No. The 3D fusion simulator was built around idiopathic scoliosis, where bending films tell how each segment moves. The measuring tools and the sagittal analysis apply to any deformity, adult degenerative scoliosis included: the Roussouly analysis recognizes the shapes of the degenerated spine, such as the false types of a retroverted pelvis. A planning module for adult deformity is in development.
With you. Cases are saved in a folder you choose on your own disk, or in your browser if you prefer, and the library is read from there when you sign in. Your account identifies you, not your patients: no radiograph, name or measurement is stored on our servers. Copying or backing up that folder is in your hands.
Yes. Drop a file, a folder or a ZIP exported from the PACS. ScolioSim reads uncompressed and compressed radiographs, takes the pixel spacing for measuring in millimeters, and keeps the full 16-bit range so window and level can be adjusted. Only the image and a short white list of tags (sex, age in years, study date) are kept; the patient's name, record number and every other tag are discarded on import.
One film is enough to measure. The sagittal analysis needs a standing lateral film that shows the femoral heads. The 3D simulator needs standing full-spine frontal and lateral films plus right and left side-bending films; segments without bending data are treated as rigid, because the simulator never assumes mobility that was not measured.
From landmarks marked on the lateral film. The pelvic incidence, which degeneration does not change, tells which of the Roussouly types the spine was built for; the sacral slope, the pelvic tilt and the apex of the lordosis tell which shape it stands in today. ScolioSim reports the difference, the angles and levels of the original shape, and how far the alignment is from proportioned according to the GAP score.
On published work, read in the original: Legaye and Duval-Beaupère on pelvic incidence and its relation to sacral slope and lordosis; Roussouly (2005) on the four types of lordosis; Laouissat (2017) on the anteverted type 3; Sebaaly (2017) on the shapes of the degenerated spine; Pizones (2019) on the ideal values of each type; Yilgor (2017) on the GAP score; and Lenke (2001) on the classification of adolescent idiopathic scoliosis.
For every motion segment from T1 to S1, the coronal angle between the two vertebrae is read on the standing film and on each bending film. The span between those measurements is the range that segment may use in the simulation.
It is what each motion segment showed it can still do. Between its angle on the standing film and its angle on each side-bending film there is a span: that span is the reserve of the segment. When you fix some segments, the free ones spend part of their reserve to bring the head back over the pelvis and level the shoulders, every one the same share of its own. ScolioSim reports the share a plan uses, and tells when the reserve is exhausted and the trunk can no longer be balanced.
Everything, to every account: anonymized DICOM import, calibrated measurements on the films, spinopelvic parameters and the Roussouly analysis, the surgical plan drawn on the film itself (PSO and SPO/Ponte osteotomies, cages, resections and slips in 2D), fitting the model on the standing and bending films, the Lenke classification, the simulation with fixed segments, asymmetric interbody supports and shoe lift, saved scenarios, the PDF report, anonymous sharing, and intraoperative composites from C-arm shots, photographed or in DICOM.
No. It is a measuring, planning and teaching aid for qualified spine surgeons. It does not replace clinical judgment.