Publications by authors named "J V C Lemans"

13 Publications

Identifying complications and failure modes of innovative growing rod configurations using the (hybrid) magnetically controlled growing rod (MCGR) and the spring distraction system (SDS).

Spine Deform 2021 Jun 22. Epub 2021 Jun 22.

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

Background: Magnetically controlled growing rods (MCGRs) offer non-invasive distractions in Early-Onset Scoliosis (EOS). However, implant-related complications are common, reducing its cost-effectiveness. To improve MCGRs functionality and cost-effectiveness, we often combine a single MCGR with a contralateral sliding rod (hybrid MCGR). Recently, we developed the spring distraction system (SDS) as an alternative, which provides continuous distraction forces through a helical spring. This study aims to identify complication rates and failure modes of EOS patients treated with either of these innovative systems.

Methods: This single-centre retrospective study included EOS patients treated with a (hybrid) MCGR or SDS between 2013 and 2018. Baseline demographics, and data regarding complications and implant growth were measured. Complication rate, complication profile, complication-free survival and implant growth were compared between groups.

Results: Eleven hybrid- and three bilateral MCGR patients (4.1-year follow-up) and one unilateral, eleven hybrid and six bilateral SDS patients (3.0-year follow-up) were included. Groups had similar age, sex, aetiology distribution, and pre-operative Cobb angle. Complication rate was 0.35 complications/patient/year for MCGR patients and 0.33 complications/patient/year for SDS patients. The most common complications were failure to distract (MCGR-group; 8/20 complications) and implant prominence (SDS-group; 5/18 complications). Median complication-free survival was 2.6 years, with no differences between groups (p = 0.673). Implant growth was significantly higher in the SDS-group (10.1 mm/year), compared to the MCGR-group (6.3 mm/year).

Conclusion: (Hybrid) MCGR and SDS patients have similar complication rates and complication-free survival. Complication profile differs between the groups, with frequent failure to distract leading to significantly reduced implant growth in (hybrid) MCGR patients, whereas SDS patients frequently exhibit implant prominence and implant kyphosis.

Level Of Evidence: III.
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http://dx.doi.org/10.1007/s43390-021-00378-4DOI Listing
June 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.

Clinical Significance: The investigated torsional device could induce apical rotation in a flexible and growing spine. Whether this may be used to reduce a scoliotic deformity remains to be investigated.
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http://dx.doi.org/10.1016/j.spinee.2021.03.015DOI Listing
March 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

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

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

Spine J 2021 04 20;21(4):671-681. 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
April 2021