Chest tube management following two row vertebral body tethering for adolescent idiopathic scoliosis.

BACKGROUND: The current gold standard of scoliosis correction procedures is still posterior spinal fusion, an extensively studied procedure. anterior vertebral body tethering is a newer surgical technique for the correction of scoliotic curves. Consequently, best practices have yet to be determined. METHODS: A single-institution, retrospective, review of all patients diagnosed with adolescent idiopathic scoliosis who underwent two row anterior vertebral body tethering between June 2020 and April 2022 was performed. RESULTS: Over the study period, 95 patients met inclusion: 79 females (83.2%) and 16 males (16.8%), age 14.4 ± 2.5 years, with a body mass index of 20.0 ± 2.9, and an average of 8.4 ± 2.1 levels treated. 28 (29.5%) procedures were for double curves and 67 (70.5%) for single curves. After tethering, a chest tube was positioned in each corrected side. A total of 123 chest tubes were analyzed, including 67 single curves and 28 double curves. Average chest tube duration was 2.5 ± 1.1 days and average length of stay was 5.0 ± 2.0 days. Average chest tube output eight hours prior to removal was 61.1 ± 45.6 mL. There was no significant difference in average length of stay for patients who underwent correction of a single curve versus a double curve nor was there a difference in average length of stay or chest tube duration for revisions compared to primary procedures. For the entire cohort, 30-day emergency department visit rate was 7.4% (n = 7) and readmission rate was 4.2% (n = 4). CONCLUSIONS: This early review of a 2-year two row vertebral body tethering postoperative experience provides a report of a safe and effective approach to chest tube management at a single academic center.

Efficient, specific, and combinatorial control of endogenous exon splicing with dCasRx-RBM25.

Efficient targeted control of splicing is a major goal of functional genomics and therapeutic applications. Guide (g)RNA-directed, deactivated (d)Cas CRISPR enzymes fused to splicing effectors represent a promising strategy due to the flexibility of these systems. However, efficient, specific, and generalizable activation of endogenous exons using this approach has not been previously reported. By screening over 300 dCasRx-splicing factor fusion proteins tethered to splicing reporters, we identify dCasRx-RBM25 as a potent activator of exons. Moreover, dCasRx-RBM25 efficiently activates the splicing of ∼90% of targeted endogenous alternative exons and displays high on-target specificity. Using gRNA arrays for combinatorial targeting, we demonstrate that dCasRx-RBM25 enables multiplexed activation and repression of exons. Using this feature, the targeting of neural-regulated exons in Ptpb1 and Puf60 in embryonic stem cells reveals combinatorial effects on downstream alternative splicing events controlled by these factors. Collectively, our results enable versatile, combinatorial exon-resolution functional assays and splicing-directed therapeutic applications.

A Comparative Evaluation of Unilateral and Bilateral Sequential Lung Isolation for Vertebral Body Tethering: A Retrospective Propensity Matched Analysis.

BACKGROUND: Vertebral body tethering (VBT) requires a thoracoscopic approach to visualize the vertebral bodies. Lung collapse and re-expansion have the potential to cause acute lung injury, resulting in increased oxygen and ventilation requirements. AIMS: We compared the intraoperative ventilator management, intra- and postoperative blood gas determinations, and hospital stay information between adolescents undergoing unilateral versus bilateral lung isolation for vertebral body tethering. METHODS:  A study cohort of 132 propensity-matched cases (66 unilateral and 66 bilateral) was derived from 351 consecutive VBT cases. Patient demographic information, case information, fluid administration, ventilatory settings data, blood gas parameters, and complete blood count and differential data were entered into a datasheet. Derived parameters included values calculated from the alveolar gas equation to develop an oxygen cascade and measures of inflammatory response. Chi-square was used for categorical data, and independent samples and t-tests were used for continuous data. RESULTS: The double lung isolation group required higher peak inspiratory pressures (SL 29±5 vs. DL 31±5, p=0.026), resulting in higher tidal volume (SL 246±63 vs. DL 334±101, p<0.001) and tidal volume per kg (SL 5.6±1.4 vs. DL 6.9±2, p<0.001) as compared to the single lung group. The double lung group required a higher partial pressure of inspired and alveolar oxygen as well as a higher alveolar to arterial oxygen tension gradient (SL 417±126 vs. DL 485±96, p=0.001) to achieve optimal arterial oxygen tension. Patients with double lung isolation had similar intensive care lengths of stay but a longer hospital stay than single lung isolation patients. CONCLUSION: Patients undergoing double lung isolation required greater ventilatory support and had more evidence of acute lung injury, as evidenced by a higher postoperative alveolar to arterial oxygen gradient; however, these healthy adolescents tolerated the procedure well and only differed in the hospital length of stay by a day.

Growth modulation response in vertebral body tethering depends primarily on magnitude of concave vertebral body growth.

PURPOSE: There is variability in clinical outcomes with vertebral body tethering (VBT) partly due to a limited understanding of the growth modulation (GM) response. We used the largest sample of patients with 3D spine reconstructions to characterize the vertebra and disc morphologic changes that accompany growth modulation during the first two years following VBT. METHODS: A multicenter registry was used to identify idiopathic scoliosis patients who underwent VBT with 2 years of follow-up. Calibrated biplanar X-rays obtained at longitudinal timepoints underwent 3D reconstruction to obtain precision morphological measurements. GM was defined as change in instrumented coronal angulation from post-op to 2-years. RESULTS: Fifty patients (mean age: 12.5 ± 1.3yrs) were analyzed over a mean of 27.7 months. GM was positively correlated with concave vertebra height growth (r = 0.57, p < 0.001), 3D spine length growth (r = 0.36, p = 0.008), and decreased convex disc height (r = - 0.42, p = 0.002). High modulators (patients experiencing GM > 10°) experienced an additional 1.6 mm (229% increase) of mean concave vertebra growth during study period compared to the Poor Modulators (GM < - 10°) group, (2.3 vs. 0.7 mm, p = 0.039), while convex vertebra height growth was similar (1.3 vs. 1.4 mm, p = 0.91). CONCLUSION: When successful, VBT enables asymmetric vertebra body growth, leading to continued postoperative coronal angulation correction (GM). A strong GM response is correlated with concave vertebral body height growth and overall instrumented spine growth. A poor GM response is associated with an increase in convex disc height (suspected tether rupture). Future studies will investigate the patient and technique-specific factors that influence increased growth remodeling.

Updated pathophysiological overview of functional MR (ventricular and atrial).

Basic mechanism of ventricular functional mitral regurgitation (FMR) is subvalvular tethering. Left ventricular (LV) dilatation, in association with mitral valve (MV) annular dilatation, causes outward displacement of papillary muscles (PMs), which abnormally pulls or tethers MV leaflets, resulting in MV tenting, reduction in leaflets coaptation and MR. Because surgical annuloplasty does shorten distance between anterior and posterior MV annuli to improve coaptation but does not address this subvalvular tethering, ventricular FMR frequently persists or recurs in the chronic stage after surgical annuloplasty. This high incidence of persistent/recurrent MR requires additional procedures to reduce subvalvular tethering. Although patients occasionally show marked improvements after annuloplasty with surgical tethering reduction procedures such as PM approximation, evidence to support benefits of such surgery is limited, requiring further trials. Recently, MV adaptation or MV leaflets tissue growth associated with LV dilatation attracts attention. Patients with larger MV leaflets with significant LV dilatation/dysfunction show less MV tethering and MR compared to those with smaller MV leaflets but with similar LV remodeling, suggesting the protective or beneficial role of MV leaflets tissue growth against LV remodeling. The MV leaflets tissue growth has the potential to lead to novel strategies of treatment for ventricular FMR. It is well known that atrial FMR is frequent in patients with left atrial dilatation, typically in those with isolated atrial fibrillation. The degree of atrial FMR is usually mild, even when it is present, and occasionally moderate, and severe atrial FMR is really rare. It is known that only severe regurgitation causes heart failure in primary MR, resulting in description on indications of surgery or intervention for only severe MR in current guidelines. Therefore, this atrial FMR up to moderate degree did not attract attention for a long time. However, recent studies have shown that patients with only moderate atrial FMR develop severe heart failure, suggesting more aggressive indication of MV surgery or intervention for "moderate" regurgitation in patients with atrial FMR. Therefore, atrial FMR is now recognized highly important. The unveiled malignant nature of atrial FMR arises many questions, including (1) why patients with only moderate atrial FMR develop heart failure? (2) do patients with mild atrial FMR develop heart failure or not?, and many others. Atrial FMR seems even more mysterious after the unveiling of its significance.

Relative predation intensity of an intertidal gastropod on artificial coastal defense structures.

Despite seawalls becoming ubiquitous coastal features, and having some physical similarities to natural rocky shores, it remains unclear how these urban habitats influence predator-prey interactions. Predators can affect intertidal mobile prey densities through two pathways: (1) successful predation directly influences prey mortality rates, and (2) direct and indirect effects of predation can scare and induce motile prey to seek safer areas. In this study, we investigated whether intertidal predators affect the density of the marine gastropod, Nerita undata, at four seawall sites in Singapore. Using a tethering method that we developed, we monitored the mortality and other evidence of predation (shell state) of tethered N. undata. Field experiments revealed high (22.5%-82.5%) predation potential of N. undata across the four sites, with significantly higher predation risk at lower shore heights and for snails with mixed shell coloration. Observations and analysis of the shell state after 3 days showed that predation on seawalls was primarily by crushing predators such as fish. Other predators of N. undata include predatory snails, with various feeding methods that left behind different predator signatures. Our results add substantially to the limited knowledge on predator-prey interactions on seawalls, particularly for Nerita undata, and suggest that seawall systems are more dynamic than previously thought. This further highlights the role of these artificial structures as important habitats and feeding grounds in urban coastal ecosystems.

lVentral tethering-is the prognosis worse than in dorsal tethering in the dysraphic spine?

OBJECTIVE: To compare cases of dysraphism with ventral tethering of cord with those with dorsal tethering and to find out any differences in the outcome of surgery in them. METHODS: We collected the data of 188 consecutively operated tethered cord patients at our institute in the past 7 years and divided them into ventral tethering and dorsal tethering groups. Those that we felt had both dorsal and ventral tethering were excluded. Their preoperative clinical, radiological, and baseline neurophysiological parameters as well as postoperative clinical and radiological parameters were analyzed in a retrospective study. RESULTS: Among the 188 tethered cord patients, 52 (28%) had ventral tethering and 136 (72%) had posterior tethering. Preoperative neurodeficit and cord signal changes as well as absent baseline MEP (of any one muscle) were significantly more associated with ventral tethered cord than the dorsal tethered cord. The neurological deterioration after surgery occurred significantly in the ventral tethered cord group than in the dorsal tethered cord group. Also, the postoperative MRI had more incomplete detethering cases in the ventral group than in the dorsal tethered cord group. CONCLUSION: Ventral tethered cord is more likely to present with preoperatively neurological deficits. It should be carefully identified in the preoperative MRI, so that the intraoperative difficulties in complete detethering and postoperative deterioration can be anticipated.

Anterior vertebral tethering for adolescent idiopathic scoliosis: our initial ten year clinical experience.

BACKGROUND: Anterior vertebral tethering (AVT) is a minimally invasive alternative to fusion surgery for adolescent idiopathic scoliosis (AIS) that offers the potential for definitive scoliosis treatment with the possibility of preservation of the growth, motion, function and overall health of the spine. This study represents our first ten years using AVT to treat AIS. METHODS: In this retrospective review we analyzed our first 74 AIS patients treated with AVT 2010-2020. Multiple Lenke curve types 33-70° were treated with skeletal maturity spanning Risser -1 to 5. RESULTS: Of 74 consecutive AIS patients treated with AVT, 52 patients (47 female, 5 male) had sufficient 2-year follow-up for inclusion. Forty-six of these 52 patients (88%) with 65 curves (35T, 30TL/L) were satisfactorily treated with AVT demonstrating curve correction from 48.6° pre-op (range 33°-70°) at age 15.1 years (range 9.2-18.8) and skeletal maturity of Risser 2.8 (range -1 to 5) to 23.2° post-op (range 0°-54°) and 24.0° final (range 0°-49°) at 3.3 years follow-up (range 2-10 years). Curve corrections from pre-op to post-op and pre-op to final were both significant (p < 0.001). The 0.8° change from post-op to final was not significant but did represent good control of scoliosis correction over time. Thoracic kyphosis and lumbar lordosis were maintained in a normal range throughout while axial rotation demonstrated a slight trend toward improvement. Skeletal maturity of Risser 4 or greater was achieved in all but one patient. Four of the 52 patients (8%) required additional procedures for tether rupture (3 replacements) or overcorrection (1 removal) to achieve satisfactory treatment status after AVT. An additional 6 of the 52 patients (12%), however, were not satisfactorily treated with AVT, requiring fusion for overcorrection (2) or inadequate correction (4). CONCLUSIONS: In this study, AIS was satisfactorily treated with AVT in the majority of patients over a broad range of curve magnitudes, curve types, and skeletal maturity. Though late revision surgery for overcorrection, inadequate correction, or tether rupture was not uncommon, the complication of overcorrection was eliminated after our first ten patients by a refinement of indications. LEVEL OF EVIDENCE: IV.

Flexible posterior vertebral tethering for the management of Scheuermann's kyphosis: correction by using growth modulation-clinical and radiographic outcomes of the first 10 patients with at least 3 years of follow-up.

PURPOSE: The present prospective cohort study was intended to present the minimum 3 years' results of flexible posterior vertebral tethering (PVT) applied to 10 skeletally immature patients with SK to question, if it could be an alternative to fusion. METHODS: Ten skeletally immature patients with radiographically confirmed SK, who had flexible (minimum 35%) kyphotic curves (T2-T12), were included. A decision to proceed with PVT was based on curve progression within the brace, and/or persistent pain, and/or unacceptable cosmetic concerns of the patient/caregivers, and/or non-compliance within the brace. RESULTS: Patients had an average age of 13.1 (range 11-15) and an average follow-up duration of 47.6 months (range 36-60). Posterior vertebral tethering (PVT) was undertaken to all patients by utilizing Wiltse approach and placing monoaxial pedicle screws intermittently. At the final follow-up: mean pre-operative thoracic kyphosis and lumbar lordosis improved from 73.6°-45.7° to 34.7°-32.1°. Mean sagittal vertical axis, vertebral wedge angle and total SRS-22 scores improved significantly. A fulcrum lateral X-ray obtained at the latest follow-up, showed that the tethered levels remained mobile. CONCLUSION: This study, for the first time in the literature, concluded, that as a result of growth modulation applied to skeletally immature patients with SK, flexible PVT was detected to yield gradual correction of the thoracic kyphosis by reverting the pathological vertebral wedging process, while keeping the mobility of the tethered segments in addition to successful clinical-functional results. The successful results of the present study answered the role of the PVT as a viable alternative to fusion in skeletally immature patients with SK. LEVEL OF EVIDENCE: IV.

The efficacy of anterior vertebral body tethering in lenke type 6 curves for adolescent idiopathic scoliosis.

PURPOSE: Spinal fusion is the standard treatment for severe forms of adolescent idiopathic scoliosis (AIS). However, with the lowest instrumented vertebra that is usually located at L3 or L4, patients are prone to develop adjacent segment degeneration in the long term. Vertebral body tethering (VBT) as motion preserving technique has become an alternative for select patients with AIS. Several studies have presented the outcome after thoracic VBT but no study has analyzed the outcome after VBT for Lenke type 6 curves. METHODS: This is a retrospective single center data analysis of patients who have had bilateral VBT for Lenke type 6 curves and a minimum follow up of 24 months. Radiographic analysis was performed on several time points. Suspected tether breakages were additionally analyzed with respect to location and time at occurrence. RESULTS: 25 patients were included. Immediate thoracic curve correction was 55.4% and 71.7% for TL/L curves. Loss of correction was higher for TL/L curves and resulted in a correction rate of 48.3% for thoracic curves and 48.9% for TL/L curves at 24 months post-operatively. 22 patients were suspected to have at least one segment with a tether breakage. Three patients required a re-VBT but no patient received posterior spinal fusion. CONCLUSION: Bilateral VBT for Lenke type 6 curves is feasible and shows a significant curve correction for thoracic and TL/L curves at a minimum of 24 months post-operatively. Tether breakage rate and loss of correction remain an unfavorable observation that needs to be improved in the future.

Delayed hemothorax after anterior vertebral body tethering in adolescent idiopathic scoliosis: a case report.

PURPOSE: The aim of this case report is to report that delayed hemothorax is possible after anterior vertebral body tethering (aVBT) and to illustrate the course of treatment. METHODS: We present a 15-year-old boy with adolescent idiopathic scoliosis who underwent an anterior thoracoscopic assisted vertebral body tethering who developed a massive right-sided hemothorax 12 days post-operatively. A chest tube was placed to drain the hemothorax and later required embolectomy with tissue plasminogen activator (TPA) to drain the retained hemothorax. RESULTS: At 1 month follow up post discharge the patient was asymptomatic, and radiograph did not demonstrate evidence of residual hemothorax and scoliosis. We have followed this patient for 5 years postoperative and he continues to do well clinically and radiographically. CONCLUSIONS: Pulmonary complications are a known drawback of anterior thoracoscopic spinal instrumentation. Delayed hemothorax is possible after aVBT. In the case of a retained hemothorax, chest tube treatment with TPA is a safe and effective method of embolectomy.

Testosterone Promotes Nerve Tethering and Acellular Biomaterial Perineural Fibrosis in a Rat Wound Repair Model.

Objective: Nerve scarring after traumatic or iatrogenic exposure can lead to impaired function and pain. Nerve-adjacent biomaterials promoting a regenerative tissue response may help reduce perineural fibrosis. Our prior work suggests that testosterone may promote fibrotic skin scarring, but it is unknown how testosterone alters nerve fibrosis or shifts the response to biomaterials. Approach: Sterilized Lewis rats received either testosterone cypionate (+T) or placebo (-T) biweekly. Fifteen days later, wounds were created over the sciatic nerve and covered with an acellular matrix (AM) or closed via primary closure (PC). At day 42, force gauge testing measured the force required to mobilize the nerve, and wound tissue was analyzed. Results: Nerve mobilization force was greater in +T versus -T wounds (p < 0.01). Nerves tore before gliding in 60% of +T versus 6% of -T rats. Epidermal gap (p < 0.01), scar width (p < 0.01), and cross-sectional scar tissue area (p = 0.02) were greater in +T versus -T rats. +T versus -T rats expressed less Col-3 (p = 0.02) and CD68 (p = 0.02). Nerve mobilization force trended nonsignificantly higher for PC versus AM wounds and for +T versus -T wounds within the AM cohort. Innovation: Testosterone increases nerve tethering in the wound healing milieu, altering repair and immune cell balances. Conclusion: Testosterone significantly increases the force required to mobilize nerves in wound beds and elevates histological markers of scarring, suggesting that testosterone-induced inflammation may increase perineural adhesion. Testosterone may reduce the potential anti-tethering protective effect of AM. Androgen receptor antagonism may represent a therapeutic target to reduce scar-related nerve morbidity.

How can biomaterial-conjugated antimicrobial peptides fight bacteria and be protected from degradation?

The emergence of antibiotic-resistant bacteria is a serious threat to public health. Antimicrobial peptides (AMP) are a powerful alternative to antibiotics due to their low propensity to induce bacterial resistance. However, cytotoxicity and short half-lives have limited their clinical translation. To overcome these problems, AMP conjugation has gained relevance in the biomaterials field. Nevertheless, few studies describe the influence of conjugation on enzymatic protection, mechanism of action and antimicrobial efficacy. This review addresses this gap by providing a detailed comparison between conjugated and soluble AMP. Additionally, commonly employed chemical reactions and factors to consider when promoting AMP conjugation are reviewed. The overall results suggested that AMP conjugated onto biomaterials are specifically protected from degradation by trypsin and/or pepsin. However, sometimes, their antimicrobial efficacy was reduced. Due to limited conformational freedom in conjugated AMP, compared to their soluble forms, they appear to act initially by creating small protuberances on bacterial membranes that may lead to the alteration of membrane potential and/or formation of holes, triggering cell death. Overall, AMP conjugation onto biomaterials is a promising strategy to fight infection, particularly associated to the use of medical devices. Nonetheless, some details need to be addressed before conjugated AMP reach clinical practice. STATEMENT OF SIGNIFICANCE: Covalent conjugation of antimicrobial peptides (AMP) has been one of the most widely used strategies by bioengineers, in an attempt to not only protect AMP from proteolytic degradation, but also to prolong their residence time at the target tissue. However, an explanation for the mode of action of conjugated AMP is still lacking. This review extensively gathers works on AMP conjugation and puts forward a mechanism of action for AMP when conjugated onto biomaterials. The implications of AMP conjugation on antimicrobial activity, cytotoxicity and resistance to proteases are all discussed. A thorough review of commonly employed chemical reactions for this conjugation is also provided. Finally, details that need to be addressed for conjugated AMP to reach clinical practice are discussed.

Mid-term outcomes of right ventricular papillary muscle approximation for severe functional tricuspid regurgitation.

OBJECTIVES: Recurrence of tricuspid regurgitation (TR) after tricuspid annuloplasty can occur in cases where a dilated right ventricle exists and subsequent leaflet tethering follows. We previously reported a new technique of the right ventricular papillary muscle approximation (RV-PMA) for functional TR associated with leaflet tethering. The objective of this study is to elucidate the mid-term outcomes and evaluate the durability of RV-PMA. METHODS: Between January 2014 and March 2023, we applied RV-PMA in 20 patients of advanced functional TR with severe leaflet tethering. The indication of the technique was severe TR with leaflet tethering height >8 mm, and/or a right ventricular end-diastolic diameter >45 mm. The patients were followed up with echocardiography before discharge and at annual interval thereafter. RESULTS: There was no perioperative mortality. In the echocardiography performed before discharge, TR was decreased to mild or less in 85%, and a significant improvement in right ventricular end-diastolic diameter and tethering height were achieved (53-45 mm and 11.1-4.4 mm, respectively). Furthermore, during the median 3-year follow-up period, TR was kept controlled mild or less in 80% of the cases. CONCLUSIONS: RV-PMA is considered to be a safe, effective and durable technique as an additional approach for tricuspid annuloplasty.

Current management of tricuspid regurgitation: a focus on the spiral suspension approach.

The indication for surgery for tricuspid regurgitation (TR) has reached a major turning point. It has become clear that the presence of moderate or severe TR alone worsens the prognosis of life, and the previous guidelines of Japanese Circulation Society, in which the indication for surgery was recommended at the timing of "right heart failure difficult to treat medically," now recommends surgery with a trigger of "repeated right heart failure" in the 2020 edition. In addition, a new repair technique targeting at subvalvular structure has been developed for end-stage TR to overcome a high TR recurrence rate that is associated with severe right ventricular enlargement and leaflet tethering. This review focuses on the spiral suspension technique, in which the papillary muscles are spirally suspended towards the septal leaflet annulus to correct tethering and enhances the understanding of its application in the context of TR management.

Analysis of three-dimensional spine growth for vertebral body tethering patients at 2 and 5 years post operatively.

PURPOSE: Scoliosis can be treated with vertebral body tethering (VBT) as a motion-sparing procedure. However, the knowledge of how growth is affected by a tether spanning multiple levels is unclear in the literature. Three-dimensional true spine length (3D-TSL) is a validated assessment technique that accounts for the shape of the spine in both the coronal and sagittal planes. This study aimed to assess if 3D-TSL increases over a five-year period after VBT implantation in thoracic curves for idiopathic scoliosis. METHODS: Prospectively collected radiographic data from an international pediatric spine registry was analyzed. Complete radiographic data over three visits (post-operative, 2 years, and 5 years) was available for 53 patients who underwent VBT. RESULTS: The mean age at instrumentation of this cohort was 12.2 (9-15) years. The average number of vertebrae instrumented was 7.3 (SD 0.7). Maximum Cobb angles were 50° pre-op, which improved to 26° post-op (p < 0.001) and was maintained at 5 years (30°; p = 0.543). Instrumented Cobb angle was 22° at 5 years (p < 0.001 vs 5-year maximum Cobb angle). An accentuation was seen in global kyphosis from 29° pre-operative to 41° at 5 years (p < 0.05). The global spine length (T1-S1 3D-TSL) started at 40.6 cm; measured 42.8 cm at 2 years; and 44.0 cm at the final visit (all p < 0.05). At 5 years, patients reached an average T1-S1 length that is comparable to a normal population at maturity. Immediate mean post-operative instrumented 3D-TSL (top of UIV-top of LIV) was 13.8 cm two-year length was 14.3 cm; and five-year length was 14.6 cm (all p < 0.05). The mean growth of 0.09 cm per instrumented level at 2 years was approximately 50% of normal thoracic growth. Patients who grew more than 0.5 cm at 2 years had a significantly lower BMI (17.0 vs 19.0, p < 0.05) and smaller pre-operative scoliosis (48° vs 53°, p < 0.05). Other subgroup analyses were not significant for age, skeletal maturity, Cobb angles or number of spanned vertebras as contributing factors. CONCLUSIONS: This series demonstrates that 3D-TSL increased significantly over the thoracic instrumented levels after VBT surgery for idiopathic scoliosis. This represented approximately 50% of expected normal thoracic growth over 2 years.

Early-term outcome of apical fusion with vertebral body tethering for thoracolumbar curves in adolescent idiopathic scoliosis: a preliminary study.

INTRODUCTION: Vertebral body tethering (VBT) has become an alternative option for select patients with idiopathic scoliosis. However, studies have shown a high number of tether breakages, specifically after thoracolumbar (TL) VBT, that can have a negative impact on the outcome, when the breakage occurs within the first year after surgery. In order to overcome this problem, we have started to apply an apical fusion (AF) in combination with TL VBT for select patients. This study aims to analyze the outcome after AF plus VBT. METHODS: This is a retrospective single surgeon's data analysis. All patients were included who have had TL VBT after January 2022 and a follow-up of 12 months. Patients were grouped based on whether they only had VBT or VBT + AF. RESULTS: Twenty-five patients were analyzed (15 VBT, 10 VBT + AF). Both groups showed a significant curve correction for thoracic and TL curves. Minor loss of correction was observed in both groups. A significant difference was seen regarding early tether breakages, which were found in 60% of VBT patients and 10% of VBT + AF patients. CONCLUSION: The preliminary data shows a significant reduction of early tether breakages when TL VBT is applied in combination with AF.

Minimally Invasive Surgery for Adolescent Idiopathic Scoliosis: A Systematic Review.

Background: Minimally invasive surgical (MIS) techniques have gained popularity as a safe and effective alternative to open surgery for degenerative, traumatic, and metastatic spinal pathologies. In adolescent idiopathic scoliosis, MIS techniques comprise anterior thoracoscopic surgery (ATS), posterior minimally invasive surgery (PMIS), and vertebral body tethering (VBT). In the current systematic review, the authors collected and analyzed data from the available literature on MIS techniques in AIS. Methods: The articles were shortlisted after a thorough electronic and manual database search through PubMed, EMBASE, and Google Scholar. Results: The authors included 43 studies for the review; 14 described the outcomes with ATS, 13 with PMIS, and 16 with VBT. Conclusions: While the efficacy of the ATS approach is well-established in terms of comparable coronal and sagittal correction to posterior spinal fusion, the current use of ATS for instrumented fusion has become less popular due to a steep learning curve, high pulmonary and vascular complication rates, implant failures, and increased non-union rates. PMIS is an effective alternative to the standard open posterior spinal fusion, with a steep learning curve and longer surgical time being potential disadvantages. The current evidence, albeit limited, suggests that VBT is an attractive procedure that merits consideration in terms of radiological correction and clinical outcomes, but it has a high complication and re-operation rate, while the most appropriate indications and long-term outcomes of this technique remain unclear.

Differential vertebral body growth is maintained after vertebral body tethering surgery for idiopathic scoliosis: 4-year follow-up on 888 peri-apical vertebrae and 592 intervertebral discs.

PURPOSE: To radiographically evaluate if vertebral body tethering (VBT) can maintain differential peri-apical vertebral growth at medium-term follow-up of 4 years. METHODS: A prospective, international, multicenter database was queried to identify idiopathic scoliosis patients treated with thoracic VBT. Concave vs. convex vertebral body height, vertebral wedging, and disc wedging of the 3 peri-apical vertebrae were measured by two independent observers at 5 timepoints (pre-operative to 4-year follow-up). RESULTS: 65 skeletally immature patients (60 female, mean 12.8 years old, 21 with open triradiate cartilages) met inclusion criteria. Mean pre-operative maximum scoliosis of 50 ± 8° decreased significantly post-operatively to 27 ± 9° (p < 0.001), which remained stable at 4-year follow-up 30 ± 17° (p = 0.38 vs. post-operative). Mean instrumented scoliosis was 21 ± 14° at 4-year follow-up, which was significantly different than 4-year maximum scoliosis (p < 0.001). Mean pre-operative kyphosis of 30 ± 12° did not significantly change post-operatively (p = 1.0) and remained stable at 4-year follow-up (35 ± 18°; p = 0.05). Mean individual convex vertebral height increased from 17.7 ± 1.9 mm to 19.8 ± 1.5 mm (p < 0.001), while mean individual concave height increased from 14.8 ± 1.9 mm to 17.6 ± 1.6 mm (p < 0.001). Summing the peri-apical heights, the difference in height from pre-operative to 4-year follow-up was greater on the concave (8.3 ± 4.7 mm) than on the convex side (6.2 ± 4.7 mm) (p < 0.001). Mean individual vertebral wedging decreased from 6 ± 2° at pre-operative to 4 ± 2° at 4-year follow-up (p < 0.001). Mean total vertebral and disc wedging started at 29 ± 7° pre-operatively, decreased to 16 ± 6° at post-operative (p < 0.001), then further decreased to 14 ± 8° at 4-year follow-up (p < 0.001). Patients with open triradiate cartilages at the time of surgery had a larger height change over the 4 years compared to those with closed triradiate cartilages (p < 0.001). CONCLUSION: Patients with idiopathic scoliosis treated with VBT demonstrated differential vertebral growth which was maintained at minimum 4-year follow-up. This effect was more pronounced in patients whose triradiate cartilages were open at the time of surgery. LEVEL OF EVIDENCE: III.

How Long Can You Delay? Curve Progression While Awaiting Vertebral Body Tethering Surgery.

Background: The implications of delaying surgical intervention for patients with adolescent idiopathic scoliosis (AIS) wishing to undergo vertebral body tethering (VBT) have not yet been explored. It is important to understand how these delays can impact surgical planning and patient outcomes. Methods: This was a retrospective review that analyzed all AIS patients treated between 2015 and 2021 at a single tertiary center. Time to surgery from initial surgical consultation and ultimate surgical plan were assessed. Patient characteristics, potential risk factors associated with increased curve progression, and reasons for delay were also analyzed. Results: 174 patients were evaluated and 95 were scheduled for VBT. Four patients later required a change to posterior spinal fusion (PSF) due to excessive curve progression. Patients requiring PSF were shown to have significantly longer delays than those who received VBT. Additionally, longer delays, younger age, greater curve progression, and lower skeletal maturity were correlated with significant curve progression (≥5 degrees). Conclusions: Surgical delays for AIS patients awaiting VBT may lead to significant curve progression and necessitate more invasive procedures. Patients with longer delays experienced an increased risk of needing PSF instead of VBT. Of those requiring PSF, the majority were due to insurance denials. Optimizing surgical timing and shared decision-making among patients, families, and healthcare providers are essential for achieving the best outcomes.