Diagnostic and therapeutic strategies in early onset scoliosis: A current concept review.

Substantial advances in the treatment of early onset scoliosis (EOS) over the past two to three decades have resulted in significant improvements in health-related quality of life of affected children. In addition to classifications that address the marked heterogeneity of this patient population, increasing understanding of the natural history of the disease, and new implants and treatment techniques have resulted in innovations unlike any other area of pediatric orthopedics. The growing understanding of the interaction between spinal and thoracic growth, as well as dependent lung maturation, has had a lasting impact on the treatment strategy of this potentially life-threatening disease. The previous treatment approach with early corrective fusion gave way to a growth-friendly concept. Despite the steady development of new growth-friendly surgical treatment options, whose efficacy still needs to be validated, as well as a revival of conservative growth control with serial casts and/or braces, the psychosocial burden of the long lasting and complication-prone treatments remains high. As a consequence, EOS still represents one of the greatest pediatric orthopedic challenges.

Safety and efficacy of growth-friendly instrumentation for early-onset scoliosis in patients with spinal muscular atrophy type 1 in the disease-modifying treatment era.

Purpose: To evaluate the safety of growth-friendly instrumentation for early-onset scoliosis (EOS) in patients with spinal muscular atrophy (SMA) type 1 who received disease-modifying treatment (DMT) and analyze short-term efficacy. Methods: Retrospective search was conducted between 2017 and 2023. Patients with genetically confirmed SMA type 1 who were surgically treated for spinal deformity and receiving DMTs (nusinersen, risdiplam, or onasemnogene abeparvovec) were included. SMA types 2 and 3 and patients who do not receive DMTs were excluded. Clinical and radiographic data were collected at preoperative, postoperative, and latest follow-up visits. Results: Twenty-eight patients (mean follow-up: 16 months (range 2-41)) were included. The mean age at surgery was 60 months (range 29-96). Fifteen were treated with dual magnetically controlled growing rods (MCGR), four with unilateral MCGR and a contralateral guided growth system, three with Vertical Expandable Prosthetic Titanium Rib (VEPTR®) implants, five with self-distracting systems, and one with traditional dual growing rods. The mean amount of correction was 57% (44°± 17) for scoliosis and 83% (13°± 11) for pelvic obliquity. The mean T1-12 height gain during surgery was 31 mm (±16 mm), while the mean T1 S1 height gain was 51 mm (±24 mm), and instrumented growth was observed during follow-up. Five patients (18%) developed six serious adverse events: three surgical site infections, two anchor failures, and one rod fracture, and all required unplanned reoperations. No neurologic complication, difficulty during nusinersen injections, or respiratory decline was recorded. Conclusion: We report that spinal deformity in this population can be safely treated with growth-friendly instrumentation, with similar complication rates when compared with SMA type 2.

The global impact of the COVID-19 pandemic on pediatric spinal care: A multi-centric study.

Background: The COVID-19 pandemic has affected healthcare worldwide since December 2019. We aimed to identify the effect of the COVID-19 pandemic on outpatient clinic and surgical volumes and peri-operative complications for pediatric spinal deformities patients. Methods: In this multi-center retrospective study, outpatient visits (in-person and virtual care) and pediatric spine surgeries volumes in four high-volume pediatric spine centers were compared between March and December 2019 and the same period in 2020. Peri-operative complications were collected and compared in the same periods. Descriptive statistics were calculated, and comparative analyses were performed. Results: During the 2020 study period, the outpatient visit (in-person and virtual care) volume decreased during local lockdown periods by 71% for new patients (p < 0.001) and 53% for returning patients (p = 0.03). Overall, for 2020, there was a 20% reduction in new patients (p = 0.001) and 21% decrease in returning patients (p < 0.001). During the pandemic, there was also 20% less overall surgical volume of adolescent idiopathic scoliosis (AIS) patients undergoing primary posterior spinal fusion, with a 70% reduction during lockdown times (p < 0.001). Complication rate and profile were similar between periods. Conclusion: There was a significant decrease in outpatient pediatric spine outpatient visits, particularly new patients, which may increase the proportion of pediatric patients with spinal deformities that present late, meeting surgical indication. This, in combination with the reduction in surgical volume of AIS over the first year of the pandemic, could result in an extended waitlist for surgeries during years to come. Complication rate was similar for both periods, suggesting it is safe to continue elective pediatric spine surgery even in a time of a pandemic. Level of evidence: level IV.

Traditional T1-S1 Measurement of the Spinal Length on X-ray Images Does Not Correlate With the True Length of the Spine.

BACKGROUND: The T1-S1 distance to evaluate spinal length is traditionally measured as a straight line on an anteroposterior radiograph. However, this method may not reflect the true 3-dimensional (3D) spinal length. The objective of the study was to evaluate the difference between the traditional T1-S1 measurement and a 3D reconstruction from standard x-ray imaging. METHODS: Radiological assessment and 3D reconstruction of spinal length in pediatric patients with various spine deformities. The 3D reconstruction derived from standard biplanar spine x-ray images using a specialized but free available software and calibration device. Direct comparison of length, intraobserver variance for repeated measurements, as well as interobserver correlation for both measurement methods and between different levels of training were evaluated. Furthermore, the influence on spinal length by the degree of spinal deformity as well as other factors was analyzed. RESULTS: A total of 39 x-ray images from 35 patients at a mean age of 15.4 years (8.9-26.8 years) were evaluated. There was excellent agreement for intra- and interobserver correlation for both measurement techniques. Spinal length assessed using 3D reconstruction was significantly longer compared with the traditional T1-S1 distance, on average 2.7 cm (0.5-6.1 cm). There was also a significant positive correlation between the maximum extent of the deformity and the difference in spinal length. CONCLUSIONS: Traditional T1-S1 distance significantly underestimates the true length of the spine. A 3D measurement reflects the real length of the spine more adequately. CLINICAL RELEVANCE: Such information is relevant to the treating spine surgeon when planning or assessing therapeutic measures, especially in advanced deformities.

Long term outcome of vertical expandable prosthetic titanium rib treatment in children with early onset scoliosis.

The vertical expandable prosthetic titanium rib (VEPTR) device was originally developed for the treatment of thoracic insufficiency syndrome with the aim of improving respiratory function of affected patients. Although clinically obvious, the changes in pulmonary function of VEPTR-treated patients are difficult to assess when using common lung function tests, and newer techniques based on functional magnetic resonance imaging (MRI) are currently being evaluated. The potential of improving lung function and simultaneously controlling the spinal deformity has continuously broadened the spectrum of indications for VEPTR, not least due to the frequent reports of complications with spine-based traditional growing rods (tGR). However, the initial enthusiasm of spine-sparing deformity correction has progressively subsided with the increasing number of reports on complications, including the detection of extraspinal ossifications along the implants and across ribs. The avoidance of repetitive surgical implant lengthening with the availability of motorized distraction-based implants has further diminished the use of VEPTR, especially in the absence of volume-depletion deformities of the thorax. In view of the still scarce reporting on the ultimate strategy of VEPTR treatment and the lack of long-term follow-up of patients receiving growth-sparing surgery, only limited conclusions can be drawn so far. Based on the available reports, however, the intended deformity corrections with final fusion surgeries can be achieved to a rather limited extent, while the complication and reoperation rates are still very high.

Radiographic Outcome and Complication Rate of 34 Graduates After Treatment With Vertical Expandable Prosthetic Titanium Rib (VEPTR): A Single Center Report.

BACKGROUND: The final strategy for graduates from growth-sparing surgery is challenging. The purpose of this study was to evaluate the radiographic outcome and complications of patients with early onset scoliosis (EOS) who have graduated from vertical expandable prosthetic titanium rib (VEPTR) treatment, either undergoing final fusion surgery or following a nonfusion approach. METHODS: Final treatment for VEPTR graduates was divided in "VEPTR in situ without final fusion," "removal of VEPTR without final fusion," and "removal of VEPTR with instrumented final fusion." Radiographic evaluations included main coronal Cobb angle and main kyphosis pre and post VEPTR implantation, at the end of implant lengthening, after final fusion (if applicable), and at latest follow-up. Complications during VEPTR treatment and in case of final fusion were reported. RESULTS: In total, 34 VEPTR graduates were included; 17 underwent final fusion surgery, and 17 followed a nonfusion strategy. Average coronal Cobb angle before VEPTR implantation was 70±23 degrees (range, 21 to 121 degrees), and 65±22 degrees (range, 17 to 119 degrees) at latest follow-up. Average main kyphosis angle was 53±27 degrees (range, 6 to 137 degrees) before VEPTR, and 69±34 degrees (range, 10 to 150 degrees) at latest follow-up. There was a 41% complication rate with final fusion surgery. CONCLUSIONS: There is a high complication rate during VEPTR treatment and with final fusion surgery. The stiffness of the spine and thorax allow for only limited correction when performing a final instrumented spondylodesis. Avoiding final fusion may be a viable alternative in case of good coronal and sagittal alignment. LEVEL OF EVIDENCE: Level IV-therapeutic.

Spinal Surgery With Electrically Evoked Potential Monitoring and Monopolar Electrocautery: Is Prior Removal of a Cochlear Implant Necessary?

: Transcranial electric stimulation to generate motor evoked potentials in lower limb muscles is the standard technique used to monitor spinal cord efferent pathways during surgical correction for spinal deformities. Monopolar electrical cauterization is also used by default in the thoracic and lumbar area of the spine during this kind of surgery to prevent major blood loss. Owing to the high levels of current used, both techniques are considered contraindicative if the patient has a cochlear implant (CI). Here, we present a CI patient who underwent corrective spinal fusion surgery for a severe kyphoscoliotic spinal deformity on whom both techniques were used without any negative effects on the CI function. A major improvement in sagittal body balance was achieved with no loss in implant-aided hearing levels. These results add to reports that CI manufactures should review their evidence underlying recommendations that transcranial electric stimulation and upper thoracic monopolar electrical cauterization are high risk for CI users, possibly initiating verification studies.

Patella instability in children and adolescents.

Patellar instabilities are the most common knee pathologies during growth. Congenital dislocations are rare. Extensive, early soft tissue releases relocate the extensor mechanism and may enable normal development of the femoro-patellar anatomy.Conservative management is the preferred strategy after a 'first-time' traumatic dislocation. In cases with concomitant anatomical predisposing factors such as trochlear dysplasia, malalignment, malrotation or ligamentous laxity, surgical reconstruction must be considered. The same applies to recurrent dislocations with pain, a sense of instability or re-dislocations which may also lead to functional compensatory mechanisms (quadriceps-avoiding gait in knee extension) or cartilaginous lesions with subsequent patello-femoral osteoarthritis. The decision-making process guiding surgical re-alignment includes analysis with standard radiographs and MRI of the trochlear groove, joint cartilage and medial patello-femoral ligament (MPFL). Careful evaluation of dynamic and static stabilisers is essential: the medial patello-femoral ligament provides stability during the first 20° of flexion, and the trochlear groove thereafter.Excessive femoral anteversion, general ligamentous laxity with increased femoro-tibial rotation, patella alta and increased distance between the tibial tuberosity and the trochlear groove must also be taken into account and surgically corrected.In cases with ongoing dislocations during skeletal immaturity, soft tissue procedures must suffice: reconstruction of the medial patello-femoral ligament as a standalone procedure or in conjuction with more complex distal realignment of the quadriceps mechanism may lead to a permanent stable result, or at least buys time until a definitive bony procedure is performed. Cite this article: Hasler CC, Studer D. Patella instability in children and adolescents. EFORT Open Rev 2016;1:160-166. DOI: 10.1302/2058-5241.1.000018.

Metamorphosis of human lumbar vertebrae induced by VEPTR growth modulation and stress shielding.

INTRODUCTION: Distraction-based spinal growth modulation by growing rods or vertical expandable prosthetic titanium ribs (VEPTRs) is the mainstay of instrumented operative strategies to correct early onset spinal deformities. In order to objectify the benefits, it has become common sense to measure the gain in spine height by assessing T1-S1 distance on anteroposterior (AP) radiographs. However, by ignoring growth changes on vertebral levels and by limiting measurement to one plane, valuable data is missed regarding the three-dimensional (3D) effects of growth modulation. This information might be interesting when it comes to final fusion or, even more so, when the protective growing implants are removed and the spine re-exposed to physiologic forces at the end of growth. METHODS: The goal of this retrospective radiographic study was to assess the growth modulating impact of year-long, distraction-based VEPTR treatment on the morphology of single vertebral bodies. We digitally measured lumbar vertebral body height (VBH) and upper endplate depth (VBD) at the time of the index procedure and at follow-up in nine patients with rib-to-ileum constructs (G1) spanning an anatomically normal lumbar spine. Nine patients with congenital thoracic scoliosis and VEPTR rib-to-rib constructs, but uninstrumented lumbar spines, served as controls (G2). All had undergone more than eight half-yearly VEPTR expansions. A Wilcoxon signed-rank test was used for statistical comparison of initial and follow-up VBH, VBD and height/depth (H/D) ratio (significance level 0.05). RESULTS: The average age was 7.1 years (G1) and 5.2 year (G2, p > 0.05) at initial surgery; the average overall follow-up time was 5.5 years (p = 1). In both groups, VBH increased significantly without a significant intergroup difference. Group 1 did not show significant growth in depth, whereas VBD increased significantly in the control group. As a consequence, the H/D ratio increased significantly in group 1 whereas it remained unchanged in group 2. The growth rate for height in mm/year was 1.4 (group 1) and 1.1 (group 2, p = 0.45), and for depth, it was -0.3 and 1.1 (p < 0.05), respectively. CONCLUSIONS: VEPTR growth modulating treatment alters the geometry of vertebral bodies by increasing the H/D ratio. We hypothesize that the implant-related deprivation from axial loads (stress-shielding) impairs anteroposterior growth. The biomechanical consequence of such slender vertebrae when exposed to unprotected loads in case of definitive VEPTR removal at the end of growth is uncertain.

Investigating the interaction of cellulose nanofibers derived from cotton with a sophisticated 3D human lung cell coculture.

Cellulose nanofibers are an attractive component of a broad range of nanomaterials. Their intriguing mechanical properties and low cost, as well as the renewable nature of cellulose make them an appealing alternative to carbon nanotubes (CNTs), which may pose a considerable health risk when inhaled. Little is known, however, concerning the potential toxicity of aerosolized cellulose nanofibers. Using a 3D in vitro triple cell coculture model of the human epithelial airway barrier, it was observed that cellulose nanofibers isolated from cotton (CCN) elicited a significantly (p < 0.05) lower cytotoxicity and (pro-)inflammatory response than multiwalled CNTs (MWCNTs) and crocidolite asbestos fibers (CAFs). Electron tomography analysis also revealed that the intracellular localization of CCNs is different from that of both MWCNTs and CAFs, indicating fundamental differences between each different nanofibre type in their interaction with the human lung cell coculture. Thus, the data shown in the present study highlights that not only the length and stiffness determine the potential detrimental (biological) effects of any nanofiber, but that the material used can significantly affect nanofiber-cell interactions.

Rapidly excised and cryofixed rat tissue.

All preparation efforts of biological samples in electron microscopy are focused to preserve structures as close as possible to the native state. To achieve this goal with tissues, it is of advantage to have a very short time between excision and fixation. The most common approach is chemical fixation: cross-linking of the tissue samples with aldehydes followed by postfixation with osmium tetroxide. Here, the fastest approach for tissue samples is perfusion. However, the diffusion of the fixation solution from blood vessels into the depth of the tissue is still slow and does not allow an overall instant fixation of a single cell. As a result, osmotic effects become evident (swelling or shrinkage of cell organelles). Another possibility is to take a tissue sample from the experimental animal. Excision of tissue can last quite some time, which results in even more pronounced autolytic induced osmotic effects. Furthermore, the animal does not survive the procedure in most cases. Alternatively, microbiopsies are an elegant technique to rapidly excise small quantities of tissue. Some tissues, such as liver and muscle, may be obtained using a non-lethal approach. To avoid the artifacts introduced by chemical fixation, high-pressure freezing of microbiopsies (brain, liver, kidney, and muscle) is a powerful alternative to chemical fixation. Here, we describe the microbiopsy method, and high-pressure freezing/freeze-substitution (HPF/FS) as a follow-up procedure. Cryosectioning of high-pressure frozen samples is optimally preserving the ultrastructure; however, it is not considered to be a routine approach yet.

A new microbiopsy system enables rapid preparation of tissue for high-pressure freezing.

A microbiopsy system was developed to overcome long sampling times for tissues before they are cryo-fixed by high-pressure freezing. A commercially available biopsy gun was adapted to the needs of small-organ excisions, and biopsy needles were modified to allow small samples (0.6 mm x 1.2 mm x 0.3 mm) to be taken. Specimen platelets with a central slot of the same dimensions as the biopsy are used. A self-made transfer device (in the meantime optimized by Leica-Microsystems [Vienna, Austria]) coordinates the transfer of the excised sample from the biopsy needle into the platelet slot and the subsequent loading in a specimen holder, which is then introduced into a high-pressure freezer (Leica EM PACT; Leica Microsystems, Vienna, Austria). Thirty seconds preparation time is needed from excision until high-pressure freezing. Brain, liver, kidney and muscle excisions of anesthetised rats are shown to be well frozen.