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result(s) for
"Tsaknakis, Konstantinos"
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Continuous lengthening potential after four years of magnetically controlled spinal deformity correction in children with spinal muscular atrophy
by
Tsaknakis, Konstantinos
,
Hecker, Marina M.
,
Lorenz, Heiko M.
in
692/308
,
692/698
,
Bone Lengthening - instrumentation
2020
Magnetically controlled growing rods (MCGR) are commonly implanted for the treatment of early-onset scoliosis. While most authors report favorable short-term results, little is known about long-term deformity correction. This prospective cohort study assesses spinal deformity control in a homogeneous spinal muscular atrophy (SMA) patient group treated with MCGR implants, a standardized lengthening protocol and a minimum follow-up of four years. 17 SMA patients with progressive scoliosis were treated with MCGR implanted parallel to the spine with rib-to-pelvis fixation. Radiologic measurements were performed before and after MCGR implantation and during external lengthening procedures. These included measurements of the scoliotic curve, kyphosis, lordosis, pelvic obliquity and the spinal length. Additional clinical data of the complications were also analyzed. 17 children (mean age 7.4 years) were surgically treated and underwent a total of 376 lengthenings. Complication rates were 3.5% in respect to all interventions or 41% of the patients had complications during 3.5% of the lengthening sessions. The initial implantation significantly reduced the main scoliotic curve by 59%, with the correction remaining constant throughout the follow-up. Pelvic obliquity was also significantly and permanently corrected by 72%, whereas kyphosis and lordosis were not influenced. The spinal length could be significantly increased mostly during the first year of treatment. Bilateral implantation of MCGRs for correction of spinal deformity in children with SMA showed no decrease of the lengthening potential during a four-year follow-up. Therefore, the previously described ‘law of diminishing returns’ could not be applied to this patient population.
Level of Evidence/Clinical relevance: Therapeutic Level IV.
Journal Article
Low bone mineral density of the spine in adolescents with cerebral palsy relates to reduced correction of scoliosis after surgery
by
Tsaknakis, Konstantinos
,
Lüders, Katja A.
,
Lorenz, Heiko M.
in
692/1537/805
,
692/700/1720
,
Adolescent
2025
Adolescents with cerebral palsy (CP) often require scoliosis surgery. Low bone mass may counteract benefits of surgical treatment. This study compares volumetric bone mineral density (vBMD) in adolescents with CP to age and sex matched healthy controls and evaluates its effect on scoliosis treatment. Computed tomogramms (CT) of 51 adolescents with CP (15.0 ± 2.6 years) were performed for scoliosis surgery and also used for vBMD calculation. Reference control vBMD values were calculated from 62 CT examinations of patients (15.1 ± 2.3 years) after trauma or conditions not related to bone mass. Z-scores were calculated based on the reference values. Correction of scoliosis in relation to vBMD was evaluated on perioperative spinal radiographs of operated adolescents with CP. Adolescents with CP had lower vBMD (123.3 ± 46.3 mg/cm
3
) than healthy controls (166.9 ± 31.4 mg/cm
3
). The lowest vBMD (97.3 ± 49.8 mg/cm
3
) had patients with CP and pathological fractures (
n
= 8). Male CP Z-scores (− 2.2 ± 1.6,
n
= 22) (16.2 ± 2.5 years) were significantly lower than female CP Z-scores (− 1.0 ± 1.3,
n
= 29) (14.1 ± 2.3 years). Higher vBMD (179.2 ± 45.4 mg/cm
3
,
n
= 41) correlated to scoliosis correction > 50% (average 67.0 ± 12%), while lower vBMD (134.9 ± 30.9 mg/cm
3
,
n
= 7) related to correction ≤ 50% (average 36.8 ± 14%). Non-ambulant adolescents with CP have lower vBMD values compared to a healthy population, which negatively affects surgical correction of scoliosis.
Level of evidence/clinical relevance: Therapeutic Level III.
Journal Article
Health-related quality of life in early-onset-scoliosis patients treated with growth-friendly implants is influenced by etiology, complication rate and ambulatory ability
by
Tsaknakis, Konstantinos
,
Braunschweig, Lena
,
Lorenz, Heiko M.
in
Age of Onset
,
Ambulatory Care - statistics & numerical data
,
Bone Lengthening - instrumentation
2019
Background
Progressive Early-Onset Scoliosis (EOS) in children may lead to surgical interventions with growth-friendly implants, which require repeated lengthening procedures in order to allow adequate growth. Quality of life was studied using the validated German version of the EOS-Questionnaire (EOSQ-24-G) in surgically treated EOS children with different lengthening modalities.
Methods
EOSQ-24-G and the KINDL
R
questionnaire were given to families with EOS children who had been treated by either
vertical expandable prosthetic titanium rib
implants and repetitive lengthening surgeries every 6 months or children who had received a
magnetically expansion controlled
implant, which was externally lengthened every 3 months. Results were compared according to differences between the two tests, and with possible influencing factors such as surgical method, severity of scoliosis, relative improvement of curvature, etiology, weight, age, travelling distance, complications, ambulatory ability and others.
Results
56 children with an average curve angle of 69° corrected to 33° (52%; average age 5.6 yrs) answered the EOSQ-24-G and the KINDL
R
after an average follow-up of 3.9 years. Health-related quality of life (HRQoL) was not affected by the initial scoliosis correction, the number of surgeries or the implant type. However, there was a negative correlation with non-ambulatory status, complications during treatment and for children with a neuromuscular scoliosis.
Conclusion
Using the validated EOSQ-24-G, no statistically significant differences were found between the group of children receiving repetitive surgeries and children with external lengthening procedures without surgery. However, results were influenced by the etiology, complication rate or ambulatory ability.
Level of Evidence/Clinical relevance
Therapeutic Level IV
Journal Article
Vertebral body changes after continuous spinal distraction in scoliotic children
2021
PurposeGrowth-friendly spinal implants (GFSI) were established for scoliotic children as an interim solution until definite spinal fusion could be performed during puberty. While deformity control was clearly proven, the effects on vertebral shape and morphology are still unclear. Our prospective study assesses the effect of GFSI with continuous distraction on vertebral body shape and volume in SMA children in comparison with previously untreated age-matched SMA patients.MethodsCohort I (n = 19, age 13.2 years) were SMA patients without prior surgical scoliosis treatment. Cohort II (n = 24, age 12.4 years) were children, who had continuous spinal distraction with GFSI for 4.5 years. Radiographic measurements and computed tomography (CT) 3D volume rendering were performed before definite spinal fusion. For cohort II, additional radiographs were analyzed before the first surgical implantation of GFSI, after surgery and every year thereafter.ResultsOur analysis revealed decreased depth and volume in scoliotic patients with prior GFSI compared to scoliotic patients without prior implants. This difference was significant for the lower thoracic and entire lumbar spine. Vertebral body height and pedicle size were unchanged between the two cohorts.ConclusionCT data showed volume reduction in the vertebral body in scoliotic children after GFSI treatment. This effect was more severe in the lumbar and lower thoracic area. While vertebral height was identical in both groups, vertebral depth was reduced in the GFSI-treated group. Reduced vertebral depth and altered vertebral morphology should be considered before instrumenting the spine in previously treated scoliotic SMA children.Level of evidence IIIDiagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.
Journal Article
Osmotic pump with potential for bone lengthening distracts continuously in vitro and in vivo
by
Schultheiß, Gerhard
,
Siegel, Marlon
,
Hell, Anna K.
in
Animals
,
Biology and Life Sciences
,
Bone lengthening
2023
In pediatric orthopedics, long bone lengthening procedures are routinely performed using manual, motorized or magnetically controlled implants. This study aims to prove expansion of a newly designed osmotic pump prior to long bone lengthening in living organisms and to rule out any complications related to in vivo conditions, such as congestion of the semipermeable membrane, local infection, or lack of water to drive the osmotic pump, as well as to compare in vivo and in vitro expansion data. Osmotic pumps, which were designed to distract a plate osteosynthesis, were inserted in the dorsal paraspinal musculature of four piglets. To compare the performance of the pumps in in vivo and in vitro conditions, another set of pumps was submerged in physiologic saline solution at different temperatures. The lengthening progress was measured radiographically and sonographically in the study animals. Both, in vitro and in vivo tested osmotic pumps started distraction after an intended rest phase of four days and distracted evenly over the following twelve days. No complications, clogging or damages occurred. However, we observed a temperature dependency of the distraction rate ranging from 0.98 mm/day at 39°C to 1.10 mm/day at 42°C. With a second setup, we confirmed that the distraction rate differed by 72% within a measured temperature interval of 14° C. The data presented here confirm that the novel osmotic pump showed comparable lengthening characteristics in vivo and in vitro. No complications, such as congestion of the semipermeable membrane, local infection, or lack of water to drive the osmotic pump were observed. Thus, osmotic pumps may have great potential in future applications such as long bone lengthening procedures, where continuous distraction probably provides a better bone quality than intermittent lengthening procedures. The fact that one pump failed to elongate in each condition, highlights the importance of technical improvement, but also demonstrates that this was not due to different circumstances within the in vivo or in vitro condition.
Journal Article
Reduced Volumetric Bone Mineral Density of the Spine in Adolescent Rett Girls with Scoliosis
by
Tsaknakis, Konstantinos
,
Jäckle, Katharina
,
Metzger, Friederike Luise
in
Anesthesia
,
Bones
,
Density
2022
In advanced Rett syndrome (RTT), limited or complete loss of ambulation, nutritional problems and scoliosis are unfavorable factors for bone mineral density (BMD). Still, there are few data available in this research area. Spinal quantitative computed tomography (QCT) allows an exact measurement of the volumetric BMD (vBMD) in this patient group. Two examiners measured vBMD of thoracic and lumbar vertebrae on asynchronous calibrated CTs that were acquired prior to surgical scoliosis correction (n = 21, age 13.6 ± 2.5 years). The values were compared to age- and sex-matched healthy controls to additionally derive Z-scores (n = 22, age 13.8 ± 2.0 years). The results showed the most significant reduction of vBMD values in non-ambulatory RTT patients, with p < 0.001 and average BMD-Z-score −1.5 ± 0.2. In the subgroup comparison, non-ambulatory patients with valproate treatment had significant lower values (p < 0.001) than ambulatory patients without valproate therapy, with an average BMD-Z-score of −2.3 ± 0.2. Comparison of the Z-scores to critical BMD thresholds of 120 and 80 mg/cm3 showed normal Z-scores in case of the ambulatory RTT subgroup, as opposed to BMD-Z-scores of the non-ambulatory RTT subgroups, which were partially below osteopenia-equivalent values. Furthermore, valproate treatment seems to have a direct effect on vBMD in RTT patients and when combined with loss of ambulation, BMD-Z-scores are reduced to osteoporosis-equivalent levels or even further.
Journal Article
A Preclinical Pilot Study on the Effects of Thermal Ablation on Lamb Growth Plates
2022
(1) Background: Thermal ablation has been demonstrated to affect the bone growth of osteoid osteoma in adolescents. Growth modulation due to thermal heat in children is conceivable, but has not yet been established. We used lamb extremities as a preclinical model to examine the effect of thermal ablation on growth plates in order to evaluate its potential for axial or longitudinal growth modulation in pediatric patients. (2) Methods: Thermal ablation was performed by electrocautery on eight different growth plates of the legs and distal radii of a stillborn lamb. After treatment, target hits and the physical extent of the growth plate lesions were monitored using micro-computed tomography (micro-CT) and histology. (3) Results: Lesions and their physical extent could be quantified in 75% of the treated extremities. The histological analysis revealed that the disruption of tissue was confined to a small area and the applied heat did not cause the entire growth plate to be disrupted or obviously damaged. (4) Conclusions: Thermal ablation by electrocautery is minimally invasive and can be used for targeted disruption of small areas in growth plates in the animal model. The results suggest that thermal ablation can be developed into a suitable method to influence epiphyseal growth in children.
Journal Article
Children With Spinal Muscular Atrophy With Prior Growth-Friendly Spinal Implants Have Better Results After Definite Spinal Fusion in Comparison to Untreated Patients
Graphical Abstract
Graphical Abstract
Journal Article
Children With Spinal Muscular Atrophy With Prior Growth-Friendly Spinal Implants Have Better Results After Definite Spinal Fusion in Comparison to Untreated Patients
by
Tsaknakis, Konstantinos
,
Braunschweig, Lena
,
von Deimling, Urs
in
Adolescent
,
Analysis
,
Atrophy
2020
Abstract
BACKGROUND
Almost all children with spinal muscular atrophy (SMA) develop a scoliosis during childhood and adolescence. In the last decades, growth-friendly spinal implants have been established as an interim solution for these patients until definite spinal fusion can be performed. The effect of those implants on the final outcome has yet to be described.
OBJECTIVE
To assess the effect of prior growth-friendly spinal surgical treatment on the outcome after spinal fusion in SMA children in comparison to untreated SMA patients through the prospective study.
METHODS
A total of 28 SMA patients with (n = 14) and without (n = 14) prior surgical treatment with growth-friendly implants were included. Average surgical treatment prior to definite spinal fusion was 4.9 yr. Scoliotic curve angle, pelvic obliquity, spinal length, kyphosis, and lordosis were evaluated for children with prior treatment and before and after dorsal spondylodesis for all children.
RESULTS
The curve angle before definite spinal fusion averaged at 104° for SMA patients without prior treatment and 71° for patients with prior treatment. Spondylodesis reduced the scoliotic curve to 50° and 33°, respectively, which equals a correction of 52% vs 54%. Pelvic obliquity could be improved by spinal fusion in all patients with better results in the pretreated group. Results for spinal length, kyphosis, and lordosis were similar in both groups.
CONCLUSION
These data show the positive effect of prior growth-friendly surgical treatment on radiographic results of spinal fusion in children with SMA. Both scoliotic curve angles and pelvic obliquity showed significantly better values when patients had growth-friendly implants before definite spinal fusion.
Graphical Abstract
Graphical Abstract
Journal Article
Non-traumatic osteochondral lesions of the knee joint during growth : Juvenile osteochondritis dissecans (JOCD) of the knee
by
Tsaknakis, Konstantinos
,
Lorenz, Heiko M
,
Afifi, Faik K
in
Adolescent
,
Cartilage, Articular - pathology
,
Child
2024
Juvenile osteochondritis dissecans of the knee joint is the most common osteochondral lesion during growth, usually occurring between the 10th and 14th year of age.
Repetitive microtraumata lead to a subchondral osseus lesion, which is commonly located at the medial aspect of the femoral condyle. Sport activities are considered to be the main cause, although genetic and hereditary factors as well as vitamin D
deficiency also play a role. Current classification systems distinguish between stable and unstable osteochondral lesions, which is decisive for further treatment.
Stable lesions may heal through conservative treatment by avoiding weight bearing and sport. Unstable lesions, on the other hand, can lead to a complete defect of the joint surface with the formation of a free joint body. In such cases, various surgical techniques aim at reconstructing the surface of the joint, in order to reduce the risk of secondary arthritis.
Journal Article