Publications by authors named "Rene M Castelein"

145 Publications

What a stranded whale with scoliosis can teach us about human idiopathic scoliosis.

Sci Rep 2021 Mar 30;11(1):7218. Epub 2021 Mar 30.

Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

Scoliosis is a deformation of the spine that may have several known causes, but humans are the only mammal known to develop scoliosis without any obvious underlying cause. This is called 'idiopathic' scoliosis and is the most common type. Recent observations showed that human scoliosis, regardless of its cause, has a relatively uniform three-dimensional anatomy. We hypothesize that scoliosis is a universal compensatory mechanism of the spine, independent of cause and/or species. We had the opportunity to study the rare occurrence of scoliosis in a whale (Balaenoptera acutorostrata) that stranded in July 2019 in the Netherlands. A multidisciplinary team of biologists, pathologists, veterinarians, taxidermists, radiologists and orthopaedic surgeons conducted necropsy and imaging analysis. Blunt traumatic injury to two vertebrae caused an acute lateral deviation of the spine, which had initiated the development of compensatory curves in regions of the spine without anatomical abnormalities. Three-dimensional analysis of these compensatory curves showed strong resemblance with different types of human scoliosis, amongst which idiopathic. This suggests that any decompensation of spinal equilibrium can lead to a rather uniform response. The unique biomechanics of the upright human spine, with significantly decreased rotational stability, may explain why only in humans this mechanism can be induced relatively easily, without an obvious cause, and is therefore still called 'idiopathic'.
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http://dx.doi.org/10.1038/s41598-021-86709-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8009909PMC
March 2021

Induction of a representative idiopathic-like scoliosis in a porcine model using a multi directional dynamic spring-based system.

Spine J 2021 Mar 20. Epub 2021 Mar 20.

Department of Orthopaedic Surgery, University Medical Center Utrecht, Heidelberglaan 100, NL-3584CX Utrecht, The Netherlands. Electronic address:

Background Context: Scoliosis is a 3D deformity of the spine in which vertebral rotation plays an important role. However, no treatment strategy currently exists that primarily applies a continuous rotational moment over a long period of time to the spine, while preserving its mobility. We developed a dynamic, torsional device that can be inserted with standard posterior instrumentation. The feasibility of this implant to rotate the spine and preserve motion was tested in growing mini-pigs.

Purpose: To test the quality and feasibility of the torsional device to induce the typical axial rotation of scoliosis while maintaining growth and mobility of the spine.

Study Design: Preclinical animal study with 14 male, 7 month old Gottingen mini-pigs. Comparison of two scoliosis induction methods, with and without the torsional device, with respect to 3D deformity and maintenance of the scoliosis after removal of the implants.

Methods: Fourteen mini-pigs received either a unilateral tether-only (n=6) or a tether combined with a contralateral torsional device (n=8). X-rays and CT-scans were made post-operative, at 8 weeks and at 12 weeks. Flexibility of the spine was assessed at 12 weeks. In 3 mini-pigs per condition, the implants were removed and the animals were followed until no further correction was expected.

Results: At 12 weeks the tether-only group yielded a coronal Cobb angle of 16.8±3.3°For the tether combined with the torsional device this was 22.0±4.0°. The most prominent difference at 12 weeks was the axial rotation with 3.6±2.8° for the tether-only group compared to 18.1±4.6° for the tether-torsion group. Spinal growth and flexibility remained normal and comparable for both groups. After removal of the devices, the induced scoliosis reduced by 41% in both groups. There were no adverse tissue reactions, implant complications or infections.

Conclusion: The present study indicates the ability of the torsional device combined with a tether to induce a flexible idiopathic-like scoliosis in mini-pigs. The torsional device was necessary to induce the typical axial rotation found in human scoliosis.
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http://dx.doi.org/10.1016/j.spinee.2021.03.015DOI Listing
March 2021

Corrigendum to 'Soft tissue sarcoma of the hand: Is unplanned excision a problem? [Eur J Surg Oncol 45/7 (2019) 1281-1287].

Eur J Surg Oncol 2021 Mar 4. Epub 2021 Mar 4.

Department of Orthopaedic Surgery, Orthopaedic Oncology Service, Massachusetts General Hospital, Harvard Medical School, Wang 435, 15 Parkman Street, Boston, MA, 02114, USA.

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http://dx.doi.org/10.1016/j.ejso.2021.02.022DOI Listing
March 2021

Specific sagittal alignment patterns are already present in mild adolescent idiopathic scoliosis.

Eur Spine J 2021 Feb 27. Epub 2021 Feb 27.

Orthopaedic Department, Centre Medico Chirurgical Les Massues Croix Rouge Française, Lyon, France.

Purpose: The complex three-dimensional spinal deformity in AIS consists of rotated, lordotic apical areas and neutral junctional zones that modify the spine's sagittal profile. Recently, three specific patterns of thoracic sagittal 'malalignment' were described for severe AIS. The aim of this study is to define whether specific patterns of pathological sagittal alignment are already present in mild AIS.

Methods: Lateral spinal radiographs of 192 mild (10°-20°) and 253 severe (> 45°) AIS patients and 156 controls were derived from an international consortium. Kyphosis characteristics (T4-T12 thoracic kyphosis, T10-L2 angle, C7 slope, location of the apex of kyphosis and of the inflection point) and sagittal curve types according to Abelin-Genevois were systematically compared between the three cohorts.

Results: Even in mild thoracic AIS, already 49% of the curves presented sagittal malalignment, mostly thoracic hypokyphosis, whereas only 13% of the (thoraco) lumbar curves and 6% of the nonscoliosis adolescents were hypokyphotic. In severe AIS, 63% had a sagittal malalignment. Hypokyphosis + thoracolumbar kyphosis occurred more frequently in high-PI and primary lumbar curves, whereas cervicothoracic kyphosis occurred more in double thoracic curves.

Conclusions: Pathological sagittal patterns are often already present in curves 10°-20°, whereas those are rare in non-scoliotic adolescents. This suggests that sagittal 'malalignment' patterns are an integral part of the early pathogenesis of AIS.
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http://dx.doi.org/10.1007/s00586-021-06772-wDOI Listing
February 2021

Letter to the editor regarding "Is rod diameter associated with the rate of rod fracture in patients treated with magnetically controlled growing rods?"

Spine Deform 2021 Feb 26. Epub 2021 Feb 26.

Department of Orthopaedic Surgery, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, The Netherlands.

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http://dx.doi.org/10.1007/s43390-021-00306-6DOI Listing
February 2021

Osteoarticular allograft reconstruction after distal radius tumor resection: Reoperation and patient reported outcomes.

J Surg Oncol 2021 Apr 9;123(5):1304-1315. Epub 2021 Feb 9.

Orthopaedic Oncology Service, Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Background: The aims of this study are to evaluate the rate of wrist joint preservation, allograft retention, factors associated with reoperation and to report the patient reported outcomes after osteoarticular allograft reconstruction of the distal radius.

Methods: Retrospective chart review identified 33 patients who underwent distal radius resection followed by osteoarticular allograft reconstruction, including 27 giant cell tumors and 6 primary malignancies. Ten patients with a preserved wrist joint completed the QuickDASH, PROMIS-CA physical function, and Toronto extremity salvage score (TESS) at a median of 13 years postoperatively.

Results: The allograft retention rate was 89%, and an allograft fracture predisposed to conversion to wrist arthrodesis. The reoperation rate was 55% and 36% underwent wrist arthrodesis at a median of 4.2 years following index surgery. The use of locking plate fixation was associated with lower reoperation and allograft fracture rates. Patients reported a median QuickDASH of 10.2 (range: 0-52.3), a mean PROMIS physical function of 57.8 (range: 38.9-64.5) and the median TESS was 95.5 (range: 67.0-98.4).

Conclusion: Osteoarticular allograft reconstruction results in acceptable long-term patient reported outcomes, despite a high revision rate. Allograft fixation with locking plates seems to reduce the number of reoperations and allograft fractures, along with reduction in wrist arthrodesis rates.
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http://dx.doi.org/10.1002/jso.26405DOI Listing
April 2021

The Effect of Functional Pelvic Tilt on the Three-Dimensional Acetabular Cup Orientation in Total Hip Arthroplasty Dislocations.

J Arthroplasty 2021 Jan 8. Epub 2021 Jan 8.

Department of Orthopedic Surgery, Keck Medical Center of the University of Southern California, Los Angeles, CA.

Background: Anterior and posterior pelvic tilt appears to play a role in total hip arthroplasty (THA) stability. When changing from the standing to the sitting position, the pelvis typically rotates posteriorly while the hips flex and this affects the femoro-acetabular positions. This case-control study compares changes in 3-D acetabular cup orientation during functional pelvic tilt between posterior THA dislocations vs stable THAs.

Methods: Standing and sitting 3-D cup orientation was compared between fifteen posterior dislocations vs 233 prospectively followed stable THAs. 3-D cup orientation was calculated using previously validated trigonometric algorithms on biplanar radiographs. Those algorithms combine the angles in the three anatomical planes (coronal inclination, transverse version, and sagittal ante-inclination) in the standing position with the change in sagittal pelvic tilt from standing to sitting to calculate the 3-D orientation in the sitting position.

Results: The standing cup orientation of the dislocated THAs was only characterized by a lower coronal inclination (P = .039). Compared with the controls, from standing to sitting, they showed less posterior pelvic tilt (P < .001). This led to a significant lower coronal inclination (P < .001) and sagittal ante-inclination (P < .001) in the sitting position but similar transverse version (P = .366).

Conclusions: Comparing posterior THA dislocations to stable THAs, there is a lower increase of all three orientation angles from standing to sitting. This leads to a decreased sitting coronal inclination and sagittal ante-inclination which may lead to an increased risk of impingement ensued by THA instability. By contrast, the transverse version was not significantly different in both positions. This confirms the importance of biplanar data on functional cup orientation.

Level Of Evidence: Diagnostic, Level III.
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http://dx.doi.org/10.1016/j.arth.2020.12.055DOI Listing
January 2021

Sagittal curvature of the spine as a predictor of the pediatric spinal deformity development.

Spine Deform 2021 Jan 15. Epub 2021 Jan 15.

Department of Orthopedic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

Background: The sagittal curvature of the spine is hypothesized to play an important role in induction of spinal deformities in adolescent idiopathic scoliosis. We previously showed an S shaped flexible rod, with the same curvature as the pediatric sagittal spinal curve, produces scoliotic-like deformities under physiologic loading. Yet, detailed characteristics of the pediatric sagittal spinal curves associated with higher risk of scoliosis are not well defined.

Methods: A total of 32 patients in a population with a high prevalence of idiopathic-like scoliosis, 22q11.2 deletion syndrome (22q), were included and followed up for at least two-years. We developed a reduced order finite element model (FEM) of the sagittal profile of these 32 patients where the spine was modeled as an S shaped elastic rod. We related the geometrical parameters of the sagittal curves and the deformed FEM of the corresponding S shaped rods to the risk of scoliosis development at two-year follow-up in this cohort.

Results: Variations in the sagittal curvature in the cohort of 22q patients resulted in five different deformity patterns shown by finite element analyses. Two sagittal plane deformity pattern groups had high rate of scoliosis development (86% and 100%) whereas the other 3 groups had less than 50% rate of scoliosis development (40%, 33%, and 0%). The pre-scoliotic position of the inflection point (where lordosis turns into kyphosis), the ratio of the spinal curvatures above and below the inflection point, and the length of the spinal curve above and below the inflection point were significantly different between the five deformity patterns groups, p < 0.05.

Conclusion: Combination of geometrical parameters of the sagittal profile prior to onset of scoliosis can relate to the development of spinal deformity in pediatric population.
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http://dx.doi.org/10.1007/s43390-020-00279-yDOI Listing
January 2021

Comparison of different strategies on three-dimensional correction of AIS: which plane will suffer?

Eur Spine J 2021 Mar 23;30(3):645-652. Epub 2020 Dec 23.

Department of Orthopaedic Surgery, G05.228, University Medical Center Utrecht, P.O. Box 85500, 35084 GA, Utrecht, The Netherlands.

Purpose: There are distinct differences in strategy amongst experienced surgeons from different 'scoliosis schools' around the world. This study aims to test the hypothesis that, due to the 3-D nature of AIS, different strategies can lead to different coronal, axial and sagittal curve correction.

Methods: Consecutive patients who underwent posterior scoliosis surgery for primary thoracic AIS were compared between three major scoliosis centres (n = 193). Patients were treated according to the local surgical expertise: Two centres perform primarily an axial apical derotation manoeuvre (centre 1: high implant density, convex rod first, centre 2: low implant density, concave rod first), whereas centre 3 performs posteromedial apical translation without active derotation. Pre- and postoperative shape of the main thoracic curve was analyzed using coronal curve angle, apical rotation and sagittal alignment parameters (pelvic incidence and tilt, T1-T12, T4-T12 and T10-L2 regional kyphosis angles, C7 slope and the level of the inflection point). In addition, the proximal junctional angle at follow-up was compared.

Results: Pre-operative coronal curve magnitudes were similar between the 3 cohorts and improved 75%, 70% and 59%, from pre- to postoperative, respectively (P < 0.001). The strategy of centres 1 and 2 leads to significantly more apical derotation. Despite similar postoperative T4-T12 kyphosis, the strategy in centre 1 led to more thoracolumbar lordosis and in centre 2 to a higher inflection point as compared to centre 3. Proximal junctional angle was higher in centres 1 and 2 (P < 0.001) at final follow-up.

Conclusion: Curve correction by derotation may lead to thoracolumbar lordosis and therefore higher risk for proximal junctional kyphosis. Focus on sagittal plane by posteromedial translation, however, results in more residual coronal and axial deformity.
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http://dx.doi.org/10.1007/s00586-020-06659-2DOI Listing
March 2021

Letter to the editor regarding "Growth‑preserving instrumentation in early‑onset scoliosis patients with multi‑level congenital anomalies".

Spine Deform 2020 Nov 23. Epub 2020 Nov 23.

Department of Orthopaedic Surgery, University Medical Center Utrecht, PO Box 85500, 3508 GA, Utrecht, The Netherlands.

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http://dx.doi.org/10.1007/s43390-020-00249-4DOI Listing
November 2020

Comparison of annulus fibrosus cell collagen remodeling rates in a microtissue system.

J Orthop Res 2020 Nov 22. Epub 2020 Nov 22.

Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

It has been suggested that curvature progression in adolescent idiopathic scoliosis occurs through irreversible changes in the intervertebral discs. Strains of mice have been identified who differ in their disc wedging response upon extended asymmetrical compression. Annulus fibrosus (AF) tissue remodeling could contribute to the faster disc wedging progression previously observed in these mice. Differences in collagen remodeling capacity of AF cells between these in-bred mice strains were compared using an in vitro microtissue system. AF cells of 8-10-week-old LG/J ("fast-healing") and C57BL/6J ("normal healing") mice were embedded in a microtissue platform and cultured for 48 h. Hereafter, tissues were partially released and cultured for another 96 h. Microtissue surface area and waistcoat contraction, collagen orientation, and collagen content were measured. After 96 h postrelease, microtissues with AF cells of LG/J mice showed more surface area contraction (p < .001) and waistcoat contraction (p = .002) than C57BL/6J microtissues. Collagen orientation did not differ at 24 h after partial release. However, at 96 h, collagen in the microtissues from LG/J AF cells was aligned more than in those from C57BL/6J mice (p < .001). Collagen content did not differ between microtissues at 96 h. AF cells of inbred LG/J mice were better able to remodel and realign their collagen fibers than those from C57BL/6J mice. The remodeling of AF tissue could be contributing to the faster disc wedging progression observed in LG/J mice.
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http://dx.doi.org/10.1002/jor.24921DOI Listing
November 2020

Spring distraction system for dynamic growth guidance of early onset scoliosis: two-year prospective follow-up of 24 patients.

Spine J 2020 Nov 20. Epub 2020 Nov 20.

Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.

Background: Current surgical treatment options for early onset scoliosis (EOS), with distraction- or growth-guidance implants, show limited growth and high complication rates during follow-up. We developed a novel implant concept, which uses compressed helical springs positioned around the rods of a growth-guidance construct. This spring distraction system (SDS) provides continuous corrective force to stimulate spinal growth, can be easily contoured, and can be used with all standard spinal instrumentation systems.

Purpose: To assess curve correction and -maintenance, spinal growth, complication rate, and health-related quality of life following SDS treatment.

Study Design: Prospective cohort study.

Patient Sample: All skeletally immature EOS patients with an indication for growth-friendly surgery and without bone- or soft tissue weakness were eligible to receive SDS. For this study, all included patients with at least 2-year follow-up were analyzed.

Outcome Measures: Coronal Cobb angle, sagittal parameters, T1-T12, T1-S1, and instrumented (ie, bridged segment) spinal height and freehand length, complications and re-operations, and the 24-Item Early Onset Scoliosis Questionnaires (EOSQ-24) score.

Methods: All primary- and conversion patients (conversion from failed other systems) with SDS and ≥2 years follow-up were included. Radiographic parameters were compared preoperatively, postoperatively and at latest follow-up. Spinal length increase was expressed as mm/year.

Results: Twenty-four skeletally immature EOS patients (18 primary and 6 conversion cases) were included. There were five idiopathic, seven congenital, three syndromic, and nine neuromuscular EOS patients. Mean age at implantation was 9.1 years (primary: 8.4; conversion: 11.2). Major curve improved from 60.3° to 35.3°, and was maintained at 40.6° at latest follow-up. Mean spring length increase during follow-up was 10.4 mm/year. T1-S1 height increased 9.9mm/year and the instrumented segment height showed a mean increase of 0.7 mm/segment/year. EOSQ-24 scores dropped after surgery from 75.6 to 67.4 but recovered to 75.0 at latest follow-up. In total, 17 reoperations were performed. Ten reoperations were performed to treat 9 implant-related complications. In addition, 7 patients showed spinal growth that exceeded expected growth velocity; their springs were retensioned during a small reoperation.

Conclusion: The 2-year follow-up results from this prospective cohort study indicate that the concept of spring distraction may be feasible as an alternative to current growing spine solutions. Curve correction and growth could be maintained satisfactory without the need for repetitive lengthening procedures. However, as in all growth-friendly implants, complications and reoperations could not be prevented, which emphasizes the need for further improvement.
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http://dx.doi.org/10.1016/j.spinee.2020.11.007DOI Listing
November 2020

Cross-validation of ultrasound imaging in adolescent idiopathic scoliosis.

Eur Spine J 2021 Mar 6;30(3):628-633. Epub 2020 Nov 6.

Department of Orthopaedic Surgery, University Medical Center Utrecht, P.O. Box 85500, 3508 GA, Utrecht, The Netherlands.

Purpose: Adolescent idiopathic scoliosis (AIS) patients are exposed to 9-10 times more radiation and a fivefold increased lifetime cancer risk. Radiation-free imaging alternatives are needed. Ultrasound imaging of spinal curvature was shown to be accurate, however, systematically underestimating the Cobb angle. The purpose of this study is to create and cross-validate an equation that calculates the expected Cobb angle using ultrasound spinal measurements of AIS patients.

Methods: Seventy AIS patients with upright radiography and spinal ultrasound were split randomly in a 4:1 ratio to the equation creation (n = 54) or validation (n = 16) group. Ultrasound angles based on the spinous processes shadows were measured automatically by the ultrasound system (Scolioscan, Telefield, Hong Kong). For thoracic and lumbar curves separately, the equation: expected Cobb angle = regression coefficient × ultrasound angle, was created and subsequently cross-validated in the validation group.

Results: Linear regression analysis between ultrasound angles and radiographic Cobb angles (thoracic: R = 0.968, lumbar: R = 0.923, p < 0.001) in the creation group resulted in the equations: thoracic Cobb angle = 1.43 × ultrasound angle and lumbar Cobb angle = 1.23 × ultrasound angle. With these equations, expected Cobb angles in the validation group were calculated and showed an excellent correlation with the radiographic Cobb angles (thoracic: R = 0.959, lumbar: R = 0.936, p < 0.001). The mean absolute differences were 6.5°-7.3°. Bland-Altman plots showed good accuracy and no proportional bias.

Conclusion: The equations from ultrasound measurements to Cobb angles were valid and accurate. This supports the implementation of ultrasound imaging, possibly leading to less frequent radiography and reducing ionizing radiation in AIS patients.
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http://dx.doi.org/10.1007/s00586-020-06652-9DOI Listing
March 2021

Variations in the sagittal spinal profile precede the development of scoliosis: a pilot study of a new approach.

Spine J 2020 Oct 28. Epub 2020 Oct 28.

Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands. Electronic address:

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http://dx.doi.org/10.1016/j.spinee.2020.10.025DOI Listing
October 2020

Deep learning-enabled MRI-only photon and proton therapy treatment planning for paediatric abdominal tumours.

Radiother Oncol 2020 12 7;153:220-227. Epub 2020 Oct 7.

Image Sciences Institute, University Medical Centre Utrecht, Utrecht, The Netherlands; MRIguidance B.V., Utrecht, The Netherlands. Electronic address:

Purpose: To assess the feasibility of magnetic resonance imaging (MRI)-only treatment planning for photon and proton radiotherapy in children with abdominal tumours.

Materials And Methods: The study was conducted on 66 paediatric patients with Wilms' tumour or neuroblastoma (age 4 ± 2 years) who underwent MR and computed tomography (CT) acquisition on the same day as part of the clinical protocol. MRI intensities were converted to CT Hounsfield units (HU) by means of a UNet-like neural network trained to generate synthetic CT (sCT) from T1- and T2-weighted MR images. The CT-to-sCT image similarity was evaluated by computing the mean error (ME), mean absolute error (MAE), peak signal-to-noise ratio (PSNR) and Dice similarity coefficient (DSC). Synthetic CT dosimetric accuracy was verified against CT-based dose distributions for volumetric-modulated arc therapy (VMAT) and intensity-modulated pencil-beam scanning (PBS). Relative dose differences (D) in the internal target volume and organs-at-risk were computed and a three-dimensional gamma analysis (2 mm, 2%) was performed.

Results: The average ± standard deviation ME was -5 ± 12 HU, MAE was 57 ± 12 HU, PSNR was 30.3 ± 1.6 dB and DSC was 76 ± 8% for bones and 92 ± 9% for lungs. Average D were <0.5% for both VMAT (range [-2.5; 2.4]%) and PBS (range [-2.7; 3.7]%) dose distributions. The average gamma pass-rates were >99% (range [85; 100]%) for VMAT and >96% (range [87; 100]%) for PBS.

Conclusion: The deep learning-based model generated accurate sCT from planning T1w- and T2w-MR images. Most dosimetric differences were within clinically acceptable criteria for photon and proton radiotherapy, demonstrating the feasibility of an MRI-only workflow for paediatric patients with abdominal tumours.
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http://dx.doi.org/10.1016/j.radonc.2020.09.056DOI Listing
December 2020

The potential of spring distraction to dynamically correct complex spinal deformities in the growing child.

Eur Spine J 2021 Mar 6;30(3):714-723. Epub 2020 Oct 6.

Department of Orthopaedic Surgery, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands.

Purpose: Current treatment of progressive early onset scoliosis involves growth-friendly instrumentation if conservative treatment fails. These implants guide growth by passive sliding or repeated lengthenings. None of these techniques provide dynamic correction after implantation. We developed the spring distraction system (SDS), by using one or multiple compressed springs positioned around a standard sliding rod, to provide active continuous distraction of the spine to stimulate growth and further correction. The purpose of this study was to determine feasibility and proof of concept of the SDS.

Methods: We developed a versatile, dynamic spring distraction system for patients who would benefit from active continuous distraction. This prospective case series evaluates four patients with exceptional and progressive congenital spine deformities.

Results: Four patients had a mean age of 6.8 years at surgery with a mean follow-up of 36 months (range 25-45). The mean progressive thoracic lordosis, which was the reason for initiating surgical treatment in two patients, changed from 32° lordosis preoperatively to 1° kyphosis post-operatively. During follow-up, this further improved to 32° thoracic kyphosis. In the two other patients, with cervicothorcacic scoliosis, the main coronal curve improved from 79° pre-operatively to 56° post-operatively and further improved to 42°. The mean T1-S1 spine growth during follow-up for all patients was 1.3 cm/year. There was one reoperation because of skin problems and no device-failures.

Conclusion: These early results show the feasibility and the proof of concept of spring-based distraction as a dynamic growth-enhancing system with the potential of further correction of the deformity after implantation.
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http://dx.doi.org/10.1007/s00586-020-06612-3DOI Listing
March 2021

Soft-tissue Sarcoma of the Hand: Patient Characteristics, Treatment, and Oncologic Outcomes.

J Am Acad Orthop Surg 2021 Mar;29(6):e297-e307

From the Department of Orthopaedic Surgery, Hand and Upper Extremity Service, Massachusetts General Hospital, Harvard Medical School, Yawkey Center, Boston, MA (Dr. Lans and Dr. Chen), the Department of Orthopaedic Surgery, Orthopaedic Oncology Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA (Ms. Yue and Dr. Lozano Calderon), the Department of Orthopedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands (Dr. Castelein), and the Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Yawkey Center, Boston, MA (Dr. Suster and Dr. Nielsen).

Introduction: The aim of this study was to describe patient characteristics, treatment, and oncologic outcomes of soft-tissue sarcomas (STSs) of the hand.

Methods: Sixty-nine STSs of the hand in adult patients treated at a tertiary referral center were retrospectively included. We describe patient and tumor characteristics along with oncologic outcomes.

Results: Epithelioid sarcoma (23%) was the most common histologic subtype, followed by synovial sarcoma (15%). Of all tumors, 17 (25%) were grade I, 22 (32%) were grade II, and 30 (44%) were grade III. The 5-year disease-free survival for epithelioid sarcomas was 75% with a disease survival of 100%, along with a metastatic rate of 15%. Of the patients with a synovial sarcoma, 40% developed metastases, and the 5-year disease-free survival was 68% and the 5-year disease survival was 73%.

Conclusion: Hand STSs are aggressive tumors with a high metastatic potential. Even with adequate oncologic treatment, long-term clinical follow-up (10 years) in these tumors is advised. The treating surgical oncologist should not be deceived by their smaller size.
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http://dx.doi.org/10.5435/JAAOS-D-20-00434DOI Listing
March 2021

Unravelling the knee-hip-spine trilemma from the CHECK study.

Bone Joint J 2020 Sep;102-B(9):1261-1267

Department of Orthopedics, University Medical Center Utrecht, Utrecht, Netherlands.

Aims: The aetiologies of common degenerative spine, hip, and knee pathologies are still not completely understood. Mechanical theories have suggested that those diseases are related to sagittal pelvic morphology and spinopelvic-femoral dynamics. The link between the most widely used parameter for sagittal pelvic morphology, pelvic incidence (PI), and the onset of degenerative lumbar, hip, and knee pathologies has not been studied in a large-scale setting.

Methods: A total of 421 patients from the Cohort Hip and Cohort Knee (CHECK) database, a population-based observational cohort, with hip and knee complaints < 6 months, aged between 45 and 65 years old, and with lateral lumbar, hip, and knee radiographs available, were included. Sagittal spinopelvic parameters and pathologies (spondylolisthesis and degenerative disc disease (DDD)) were measured at eight-year follow-up and characteristics of hip and knee osteoarthritis (OA) at baseline and eight-year follow-up. Epidemiology of the degenerative disorders and clinical outcome scores (hip and knee pain and Western Ontario and McMaster Universities Osteoarthritis Index) were compared between low PI (< 50°), normal PI (50° to 60°), and high PI (> 60°) using generalized estimating equations.

Results: Demographic details were not different between the different PI groups. L4 to L5 and L5 to S1 spondylolisthesis were more frequently present in subjects with high PI compared to low PI (L4 to L5, OR 3.717; p = 0.024 vs L5 to S1 OR 7.751; p = 0.001). L5 to S1 DDD occurred more in patients with low PI compared to high PI (OR 1.889; p = 0.010), whereas there were no differences in L4 to L5 DDD among individuals with a different PI. The incidence of hip OA was higher in participants with low PI compared to normal (OR 1.262; p = 0.414) or high PI (OR 1.337; p = 0.274), but not statistically different. The incidence of knee OA was higher in individuals with a high PI compared to low PI (OR 1.620; p = 0.034).

Conclusion: High PI is a risk factor for development of spondylolisthesis and knee OA. Low pelvic incidence is related to DDD, and may be linked to OA of the hip. Level of Evidence: 1b Cite this article: 2020;102-B(9):1261-1267.
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http://dx.doi.org/10.1302/0301-620X.102B9.BJJ-2019-1315.R2DOI Listing
September 2020

The heritability of coronal and sagittal phenotype in idiopathic scoliosis: a report of 12 monozygotic twin pairs.

Spine Deform 2021 Jan 6;9(1):51-55. Epub 2020 Aug 6.

Department of Orthopaedic Surgery, OLVG, Amsterdam, The Netherlands.

Purpose: One of the pathways through which genetics may act in the causation of idiopathic scoliosis is inheritance of a specific sagittal profile that predisposes for its development. In this study, coronal and sagittal parameters were compared in an international collection of monozygotic twins with idiopathic scoliosis.

Methods: Twelve monozygotic twin pairs who underwent biplanar radiography for idiopathic scoliosis were systematically identified in existing scoliosis databases in The Netherlands, Sweden, and Denmark. On the first available radiographs, the coronal and sagittal curve parameters (Roussouly and Abelin types, thoracic kyphosis, lumbar lordosis and length of the posteriorly inclined segment) were determined.

Results: In all 12 monozygotic twin pairs, both twins were affected by AIS. Four (33%) twin pairs had similar coronal and sagittal spinal phenotype, whereas two (17%) had different coronal phenotype and similar sagittal profiles, and six (50%) pairs had different coronal as well as sagittal phenotype.

Conclusions: Analysis of biplanar curve characteristics in monozygotic twins showed that all twin pairs were affected by idiopathic scoliosis. However, only 33% of the pairs had similar coronal and sagittal spinal phenotypes. Based on this limited dataset, the hypothesis can be formulated that besides genetic pre-disposition, the individual (inherited) sagittal profile plays a role in the development of different coronal curve type.
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http://dx.doi.org/10.1007/s43390-020-00172-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7775859PMC
January 2021

Idiopathic Scoliosis as a Rotatory Decompensation of the Spine.

J Bone Miner Res 2020 10 9;35(10):1850-1857. Epub 2020 Sep 9.

Académie Nationale de Médecine, Paris, France.

Many years of dedicated research into the etiology of idiopathic scoliosis have not led to one unified theory. We propose that scoliosis is a mechanical, rotatory decompensation of the human spine that starts in the transverse, or horizontal, plane. The human spine is prone to this type of decompensation because of its unique and individually different, fully upright sagittal shape with some preexistent transverse plane rotation. Spinal stability depends on the integrity of a delicate system of stabilizers, in which intervertebral disc stiffness is crucial. There are two phases in life when important changes occur in the precarious balance between spinal loading and the disc's stabilizing properties: (i) during puberty, when loads and moment arms increase rapidly, while the disc's "anchor," the ring apophysis, matures from purely cartilaginous to mineralized to ultimately fused to the vertebral body, and (ii) in older age, when the torsional stiffness of the spinal segments decreases, due to disc degeneration and subsequent laxity of the fibers of the annulus fibrosus. During these crucial periods, transverse plane vertebral rotation can increase during a relatively brief window in time, either as adolescent idiopathic or degenerative de novo scoliosis. Much more is known of the biomechanical changes that occur during disc aging and degeneration than of the changing properties of the disc during maturation. © 2020 American Society for Bone and Mineral Research (ASBMR).
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http://dx.doi.org/10.1002/jbmr.4137DOI Listing
October 2020

Benign Hand Tumors (Part II): Soft Tissue Tumors.

Hand (N Y) 2020 Jul 15:1558944720928499. Epub 2020 Jul 15.

Harvard Medical School, Boston, MA, USA.

Benign soft-tissue tumors of the hand are more common than both their benign bone and malignant soft-tissue counterparts. This study evaluates the characteristics and treatment of benign soft tissue tumors in light of 1 institution's experience. Histologically confirmed benign soft-tissue tumors of the hand were retrospectively identified using International Classification of Disease codes from 1992 to 2015. A medical chart review was conducted to collect patient demographics, tumor epidemiology, and treatment. A total of 199 soft-tissue tumors were identified. The median patient age at time of treatment was 47.4 ± 14.7 years in age. The majority of tumors were located in the digits (n = 168, 84%) and treated by excision (n = 191, 96%). Localized type tenosynovial giant cell tumors (n = 71, 36%) were the most common and had the highest rates of recurrence (8.5%) in this series. Other frequent histologies included hemangioma, schwannoma, and glomus tumors. Awareness and understanding of tumor characteristics may help physicians with diagnosis and treatment. There is an extensive variety of tumors, but the principles of clinical and imaging diagnosis are common to all of them. Marginal excision for the treatment pain, improvement of function, and cosmetic correction applies to all these tumors independent of the histology.
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http://dx.doi.org/10.1177/1558944720928499DOI Listing
July 2020

Giant Cell Tumors of the Upper Extremity: Predictors of Recurrence.

J Hand Surg Am 2020 Aug 29;45(8):738-745. Epub 2020 Jun 29.

Department of Orthopaedic Surgery, Orthopaedic Oncology Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA.

Purpose: Giant cell tumors (GCT) of the distal radius are thought to be more aggressive than in other locations. Therefore, the aim of this study was to investigate factors associated with recurrence of GCTs in the upper extremity.

Methods: We retrospectively identified 82 patients who underwent primary surgical treatment for an upper extremity GCT. Tumors were located in the radius (n = 47), humerus (n = 17), ulna (n = 9), and hand (n = 9). Treatment consisted of either wide resection or amputation or intralesional resection with or without adjuvants. A multivariable logistic regression was performed including tumor grade, type of surgery, and tumor location, from which the percentage of contribution to the model of each variable was calculated.

Results: The recurrence rate after intralesional resection was 48%; after wide resection or amputation, it was 12%. Two patients developed a pulmonary metastasis (2.4%). In multivariable analysis, intralesional resection was independently associated with recurrence. Intralesional resection had a 77% contribution to predict recurrence and the distal radius location had a 16% contribution in the predictive model.

Conclusions: As expected, intralesional resection was the strongest independent predictor of recurrence after surgical treatment for GCT. The distal radius location contributed to the prediction of giant cell tumor recurrence to a lesser extent.

Type Of Study/level Of Evidence: Prognostic IV.
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http://dx.doi.org/10.1016/j.jhsa.2020.04.020DOI Listing
August 2020

Spinal Growth in Patients With Juvenile Idiopathic Scoliosis Treated With Boston Brace: A Retrospective Study.

Spine (Phila Pa 1976) 2020 Jul;45(14):976-982

Department of Orthopaedic Surgery, OLVG, Amsterdam, The Netherlands.

Study Design: Retrospective comparative cohort.

Objective: The aim of this study was to determine whether spinal growth is restricted by brace treatment in patients with juvenile idiopathic scoliosis (JIS).

Summary Of Background Data: Spinal fusion can negatively affect spinal growth if performed before the growth spurt. Brace treatment is often given in this young population to control the spinal deformity while allowing spinal growth. It is unknown whether the applied pressure of brace treatment on spine results in growth restriction. The aim of the study is to evaluate spinal growth in braced JIS patients.

Methods: A total of 49 JIS patients treated with Boston brace were retrospectively selected from a scoliosis database. T1-T12/T1-S1 perpendicular and freehand (height following the curvature of the spine) height were measured on radiographs of patients that had reached skeletal maturity and were matched with 49 controls without scoliosis. Spinal growth was calculated from brace initiation until cessation and was compared with normal spinal growth values as reported by Dimeglio.

Results: The mean age of diagnosis was 7.4 years. The age of the braced scoliosis patients at skeletal maturity was 17.5 years. The average T1-T12 and T1-S1 freehand height measured by following the curvature of the scoliosis was 29.3 cm (±2.4) and 47.2cm (±4.0), respectively, and was not significant different from the control group. Brace treatment was initiated at a mean age of 11.2 and the mean age of cessation was 14.8. Spinal growth (freehand) during brace treatment was 1.10 cm/year for the thoracic spine and 1.78 cm/year for the full spine and was not significant different from normal values.

Conclusion: No significant influence of bracing on spinal growth could be detected in this cohort of JIS patients. The spinal height measurements at skeletal maturity were similar to matched controls. In addition, spinal growth did not significantly differ from Dimeglio normal growth data, indicating that the effect of bracing on spinal growth is absent or minimal.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003435DOI Listing
July 2020

Benign Hand Tumors (Part I): Cartilaginous and Bone Tumors.

Hand (N Y) 2020 Jun 6:1558944720922921. Epub 2020 Jun 6.

Harvard Medical School, Boston, MA, USA.

Benign tumors of the hand present in a wide array of histological subtypes and compose most of the bony tissue tumors in the hand. This study evaluates the characteristics and treatment of benign bone tumors in light of one institution's experience. Histologically confirmed benign tumors of the hand were retrospectively identified using International Classification of Diseases codes from 1992 to 2015. A medical chart review was conducted to collect patient characteristics and tumor epidemiology and treatment. A total of 155 benign bone tumors were identified. The median age of patients at the time of surgery was 39.9 ± 12.8 years. All bone tumors were located in the digits, and most were treated by intralesional curettage (n = 118, 76%). Pathologic fractures occurred in 79 bone tumors (51%). Enchondromas (n = 118, 76%) were the most common bone tumor in this series, whereas giant cell tumors were the most destructive and also had the highest recurrence rate (40%). Awareness of tumor features may help physicians with diagnosis, and awareness of recurrence rates is important when counseling patients.
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http://dx.doi.org/10.1177/1558944720922921DOI Listing
June 2020

Increasing Fusion Rate Between 1 and 2 Years After Instrumented Posterolateral Spinal Fusion and the Role of Bone Grafting.

Spine (Phila Pa 1976) 2020 Oct;45(20):1403-1410

Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands.

Study Design: Two-year clinical and radiographic follow-up of a double-blind, multicenter, randomized, intra-patient controlled, non-inferiority trial comparing a bone graft substitute (AttraX Putty) with autograft in instrumented posterolateral fusion (PLF) surgery.

Objectives: The aim of this study was to compare PLF rates between 1 and 2 years of follow-up and between graft types, and to explore the role of bone grafting based on the location of the PLF mass.

Summary Of Background Data: There are indications that bony fusion proceeds over time, but it is unknown to what extent this can be related to bone grafting.

Methods: A total of 100 adult patients underwent a primary, single- or multilevel, thoracolumbar PLF. After instrumentation and preparation for grafting, the randomized allocation side of AttraX Putty was disclosed. The contralateral posterolateral gutters were grafted with autograft. At 1-year follow-up, and in case of no fusion at 2 years, the fusion status of both sides of each segment was blindly assessed on CT scans. Intertransverse and facet fusion were scored separately. Difference in fusion rates after 1 and 2 years and between grafts were analyzed with a Generalized Estimating Equations (GEE) model (P < 0.05).

Results: The 2-year PLF rate (66 patients) was 70% at the AttraX Putty and 68% at the autograft side, compared to 55% and 52% after 1 year (87 patients). GEE analysis demonstrated a significant increase for both conditions (odds ratio 2.0, 95% confidence interval 1.5-2.7, P < 0.001), but no difference between the grafts (P = 0.595). Ongoing bone formation was only observed between the facet joints.

Conclusion: This intra-patient controlled trial demonstrated a significant increase in PLF rate between 1 and 2 years after instrumented thoracolumbar fusion, but no difference between AttraX Putty and autograft. Based on the location of the PLF mass, this increase is most likely the result of immobilization instead of grafting.

Level Of Evidence: 1.
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http://dx.doi.org/10.1097/BRS.0000000000003558DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7515483PMC
October 2020

Can dual mobility cups prevent dislocation without increasing revision rates in primary total hip arthroplasty? A systematic review.

Orthop Traumatol Surg Res 2020 05 8;106(3):509-517. Epub 2020 Apr 8.

Department of Orthopaedic Surgery, OLVG, PO Box 95500, 1090 HM Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Leiden University Medical Center, PO Box 9600, 2300 RC Leiden, The Netherlands.

Background: Dislocation is one of the leading causes for early revision surgery after total hip arthroplasty (THA). To address this problem, the dual mobility (DM) cup was developed in the 1970s by the French. Despite the increased and, in some countries, broad use of DM cups, high quality evidence of their effectiveness compared to traditional unipolar (UP) cups is lacking. There are a few well-conducted literature reviews, but the level of evidence of the included studies was moderate to low and the rates of revision were not specifically investigated. Therefore, we did a systematic review to investigate whether there is a difference in the rate of dislocations and revisions after primary THA with a DM cup or a UP cup.

Methods: We conducted a systematic literature search in PubMed, Embase and Cochrane databases in July 2019. The articles were selected based upon their quality, relevance and measurement of the predictive factor. We used the MINORS criteria to determine the methodological quality of all studies.

Results: The initial search resulted in 702 citations. After application of the inclusion and exclusion criteria, eight articles met our eligibility criteria and were graded. Included studies were of medium to low methodological quality with a mean score of 14/24 (11-16) points following the MINORS criteria. In the case-control studies, a total of 549 DM cups and 649 UP cups were included. In the registry studies, a total of 5.935 DM cups and 217.362 UP cups were included. In the case-control studies, one (0.2%) dislocation was reported for the DM cups and 46 (7.1%) for the UP cup (p=0.009, IQR=0.00-7.00). Nine (1.6%) revisions, of which zero due to dislocation, were reported for the DM cup and 39 (6.0%), of which 30 due to dislocation, for the UP cup (p=0.046, CI=-16.93-5.73). In the registry studies 161 (2.7%) revisions were reported for the DM cup, of which 14 (8.7%) due to dislocation. For the UP cup, 3.332 (1.5%) revisions were reported (p=0.275, IQR=41.00-866.25), of which 1.093 (32.8%) due to dislocation (p=0.050, IQR=3.50-293.25).

Conclusion: This review suggests lower rates of dislocation and lower rates of revision for dislocation in favor of the DM cups. Concluding, DM cups might be an effective solution to reduce dislocation in primary THA. To evaluate the efficacy of DM cups compared to UP cups, an economic evaluation alongside a randomized controlled trial is needed focusing on patient important endpoints.

Level Of Evidence: III, systematic review of level III studies.
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http://dx.doi.org/10.1016/j.otsr.2019.12.019DOI Listing
May 2020

3-Year follow-up of a single magnetically controlled growing rod with contralateral gliding system and apical control for early onset scoliosis.

Spine Deform 2020 08 30;8(4):751-761. Epub 2020 Mar 30.

Department of Orthopaedic Surgery, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus, Denmark.

Study Design: Two-center retrospective cohort study.

Objective: The aim of this study is to investigate the clinical effectiveness and safety of the MCGR hybrid in terms of spinal growth, 3D correction, balance, and complications. The magnetic-controlled growing-rod (MCGR) growth instrumentation method has gained popularity for early onset scoliosis (EOS) treatment in the past years due to the non-invasiveness of the subsequent interval elongation procedures. To improve 3D correction and reduce the costs, we combined a single concave MCGR with a sliding rod on the convex side to control the apex.

Methods: A retrospective cohort study of 18 EOS children with an average 3-year follow-up (range 2.0-3.7) from two European spine centers treated with the single MCGR hybrid concept; 14 primary and 4 conversion cases. The primary and conversion cases were both evaluated preoperatively, postoperatively, 1 year, 2 years, and last follow-up.

Results: Mean age was 9.9 (SD ± 2.9 years). The average frontal Cobb angle was reduced from mean 65° to 30° postoperatively, and had increased to 37° at latest follow-up. Rotation of the apical vertebra improved from mean 27° to 20° postoperatively which was partially lost to 23°. Kyphosis and lordosis both increased by an average of 5° during the time of follow-up. Spinal balance was improved. The post-implantation T1-S1 spine growth rate averaged 10 mm/year at last follow-up. There were 13 implant-related complications in 6 out of 18 patients. No screw pull-outs and nor surgical site infections were registered.

Conclusions: This is the first medium-term results of a single MCGR hybrid construct. Maintenance of correction and growth are reasonable, and the complication rate is relatively low as compared to bilateral MCGR application.

Level Of Evidence: III.
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http://dx.doi.org/10.1007/s43390-020-00098-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7366570PMC
August 2020

Anterior lengthening in scoliosis occurs only in the disc and is similar in different types of scoliosis.

Spine J 2020 10 14;20(10):1653-1658. Epub 2020 Mar 14.

Department of Orthopedic Surgery, University Medical Center Utrecht, P.O. Box 85500, Utrecht 3508, the Netherlands. Electronic address:

Background Context: Relative anterior spinal overgrowth was proposed as a generalized growth disturbance and a potential initiator of adolescent idiopathic scoliosis (AIS). However, anterior lengthening has also been observed in neuromuscular (NM) scoliosis and was shown to be restricted to the apical areas and located in the intervertebral discs, not in the bone. This suggests that relative anterior spinal overgrowth does not rightfully describe anterior lengthening in scoliosis, as it seems not a generalized active growth phenomenon, nor specific to AIS.

Purpose: To determine if compensatory curves in congenital scoliosis exhibit a mechanism of anterior lengthening without changes in the vertebral body, similar to curves in AIS and NM scoliosis.

Study Design/setting: Cross-sectional.

Patient Sample: CT-scans were included of patients in whom a short segment congenital malformation had led to a long thoracic compensatory curve without bony abnormality. Based on data of other scoliosis types, the calculated required sample size was n=12 to detect equivalence of vertebral bodies as compared with nonscoliotic controls. Out of 143 congenital scoliosis patients, 18 fit the criteria and compared with 30 nonscoliotic controls, 30 AIS and 30 NM scoliosis patients.

Outcome Measures: The anterior-posterior length discrepancy (AP%) of the total curve and for vertebral bodies and intervertebral discs separately.

Methods: Of each vertebral body and intervertebral disc in the compensatory curve, the anterior and posterior length was measured on CT-scans in the exact mid-sagittal plane, corrected for deformity in all three planes. The AP% was calculated for the total compensatory curve (Cobb-to-Cobb) and for the vertebral bodies and the intervertebral discs separately. Positive AP% indicated that the anterior side was longer than the posterior side.

Results: The total AP% of the compensatory curve in congenital scoliosis showed lordosis (+1.8%) that differed from the kyphosis in nonscoliotic controls (-3.0%; p<.001) and was comparable to the major curve in AIS (+1.2%) and NM scoliosis (+0.5%). This anterior lengthening was not located in the bone; the vertebral body AP% showed kyphosis (-3.2%), similar to nonscoliotic controls (-3.4%) as well as AIS (-2.5%) and NM scoliosis (-4.5%; p=1.000). However, the disc AP% showed lordosis (+24.3%), which sharply contrasts to the kyphotic discs of controls (-1.5%; p<.001), but was similar to AIS (+17.5%) and NM scoliosis (+20.5%).

Conclusions: The current study on compensatory curves in congenital scoliosis confirms that anterior lengthening is part of the three-dimensional deformity in different types of scoliosis and is exclusively located in the intervertebral discs. The bony vertebral bodies maintain their kyphotic shape, which indicates that there is no active anterior bony overgrowth. Anterior lengthening appears to be a passive result of any scoliotic deformity, rather than being related to the specific cause of AIS.
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http://dx.doi.org/10.1016/j.spinee.2020.03.005DOI Listing
October 2020