Progressive Spinal Deformity Research Articles

Clinically relevant finite element technique based protocol to evaluate growing rods for early onset scoliosis correction.

ObjectiveThe emergence of distraction‐based growing rods has provided the means to reduce the progression of spinal deformity in early onset scoliosis (EOS). The current protocols for evaluating spinal implants (ie, ASTM‐F1717 and ISO‐12189) were developed for fusion/dynamic devices. These protocols do not feature long unsupported rod lengths subjected to distraction. Due to the unsuitability of the existing guidelines for the evaluation of growing rods, a new distraction‐based finite element protocol is presented herein for the first time.MethodA vertebrectomy (VO) model from current protocols was modified to accommodate multi‐spinal segments (ie, MS model) in which springs with appropriate stiffness were simulated in between the plastic blocks. To assess the efficacy of the protocol, two different computational studies were conducted: (a) compression‐bending (MS‐CB) with no distraction, and (b) distraction followed by compression‐bending (MS‐D + CB). In each study, the model with no axial connector (rods‐only) was modified to include a) 80‐mm long tandem (LT) connectors, and b) side‐by‐side (SBS) connectors. Stiffness and yield loads were calculated as per ASTM‐F1717 guidelines and compared with the corresponding VO models with no distraction. In the MS‐D + CB models, distraction was applied at the top block, stretching the spring‐block construct in a simulation of scoliosis surgery prior to locking the construct at the connector‐rods' interface.ResultsMS‐CB models predicted higher stiffness and yield loads, compared to the VO models. The locking mechanism produced pre‐existing stresses on the rod‐connector interface, which caused a shift in the location of high‐stress regions to the distraction site. Distraction led to a decrease in the construct's stiffness and yield load.DiscussionThe proposed protocol enables the simulation of clinical parameters that are not feasible in the F1717 models and predicted stress patterns in the hardware consistent with observed clinical failures.

Spinal injuries in the elderly population

The average age of the population is increasing and spinal traumatic injuries of the elderly are significantly more common. This frail population is prone to suffering serious injuries from minor or low-impact trauma when compared to younger patients. The reduced agility and ability to avoid falls in the elderly population may be the result of a combination of decreased stability due to altered sensory mechanisms, progressive spinal deformity, increased rigidity, osteoarthritis and neurological disorders, reduced cognitive function and hypotension, along with polypharmacy. Associated risk factors, including metabolic and autoimmune conditions may significantly increase the risk of morbidity and disability in this group. The most frequent injuries are odontoid fractures, vertebral compression fractures and traumatic central cord syndrome, all of which may be frequently associated with other lesions. Patient resilience and expectations will determine selection of consensual treatment aiming for a balance between maintaining function and achieving recovery. Conservative management is often the preferred method of treatment in the most common spinal injuries in the elderly as non-union or some degree of spinal deformity may be clinically well tolerated. Surgical treatment may provide benefit in the presence of persistent cord compression or spinal instability in patients that can tolerate the procedure. Ultimately, treatment should be tailored individually. Prevention of these injuries should be the focus in a world population with an ever-increasing proportion of elderly people.

Osteomyelitis-Discitis at the Thoracolumbar Junction and the Development of Postinfectious Spinal Deformity: A Surgical Case Series

Progressive spinal deformity and neural compromise are the main indications for surgical management of vertebral osteomyelitis-discitis. However, when such pathology presents at the thoracolumbar (TL) junction, it remains unclear what the appropriate intervention is. The therapeutic dilemmas of decompression with or without instrumented fusion, the need for circumferential decompression and reconstruction, as well as the prognostic factors for progression of kyphosis, all remained ill-defined in the literature. The objective of this study is to evaluate risk factors for instrumentation at TL junction in spinal osteomyelitis-discitis. A review of patients at a single center with osteomyelitis-discitis at the TL junction between 2014 and 2018 was performed. Patients were 18 years or older with infectious pathologies at T10 to L2. Sixteen patients were included. Indication for instrumentation included progression of kyphosis following prior laminectomy/medical management. Of the 16 patients, 4 patients received laminectomy at initial treatment versus 12 patients receiving medical management alone. All 4 patients receiving laminectomy experienced progressive kyphosis requiring revision with instrumented fusion versus only 4 of 12 of the medically managed. Laminectomy, epidural compression, and vertebral body collapse were significant risk factors for kyphosis progression requiring instrumentation. The average time to surgical intervention for the indication of progressive kyphosis was 2.6 months after prior laminectomy and 6 months after initiation of medical management. Given the proclivity for kyphotic deformity at the TL junction, patients may benefit from long segment instrumentation in addition to decompression at the initial surgery. Laminectomy alone may hasten kyphosis progression.

Examination of the changes in lower extremities related to progression of adult spinal deformity: a longitudinal study of over 22\xa0years

This longitudinal observational study investigated the relationship between changes in spinal sagittal alignment and changes in lower extremity coronal alignment. A total of 58 female volunteers who visited our institution at least twice during the 1992 to 1997 and 2015 to 2019 periods were investigated. We reviewed whole-spine radiographs and lower extremity radiographs and measured standard spinal sagittal parameters including pelvic incidence [PI], lumbar lordosis [LL], pelvic tilt [PT], sacral slope [SS] and sagittal vertical axis [SVA], and coronal lower extremity parameters including femorotibial angle (FTA), hip–knee–ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA) and mechanical lateral distal tibial angle (mLDTA). Lumbar spondylosis and knee osteoarthritis were assessed using the Kellgren–Lawrence (KL) grading system at baseline and at final follow-up. We investigated the correlation between changes in spinal sagittal alignment and lower extremity alignment and changes in lumbar spondylosis. The mean age [standard deviation (SD)] was 48.3 (6.3) years at first visit and 70.2 (6.3) years at final follow-up. There was a correlation between changes in PI-LL and FTA (R = 0.449, P < 0.001) and between PI-LL and HKA (R = 0.412, P = 0.001). There was a correlation between changes in lumbar spondylosis at L3/4 (R = 0.383, P = 0.004) and L4/5 (R = 0.333, P = 0.012) and the knee joints. Changes in lumbar spondylosis at L3/4 and L4/5 were related to changes in KOA. Successful management of ASD must include evaluation of the state of lower extremity alignment, not only in the sagittal phase, but also the coronal phase.

Do Children With Spinal Deformity Who Have Metal Implants and Frequent Exposure to X-Rays Increase Their Risk of Cancer?

Spinal surgery cohort. The authors assess the risk of cancer in children who have undergone frequent radiographs and have metal implants for the treatment of spinal deformity. Concerns have been raised regarding the cancer risk to children exposed to repeated radiological examinations as part of routine surveillance to monitor progression of spinal deformity. Additionally, there are reports of increased cancer risk in adults having joint replacement with metal implants causing raised metal ion levels in the blood. A large number of consecutive children undergoing instrumented spinal surgery since 1979 were examined for their development of malignancy. High quality data on all invasive cancers from the South Australian Cancer Registry and deaths were linked to the spinal surgery cohort with the calculation of standardized incidence ratios (SIRs) using the Quinquinquennium method. The study cohort was formed by 865 children. The average follow-up time from date of surgery to either death or censoring date was 18 years with a maximum of 36 years. A total of 15,921 person years were examined. There was no increased rate of cancer in these patients. For the total cohort, the SIR was 1.00 (95% confidence interval [CI] 0.50-1.79). For females the SIR was 0.83 (95% CI 0.33-1.70) and for males the SIR was 1.33 (95% CI 0.36-3.40). The male SIR reflected an expected cancer incidence of three cases, when four cases were observed, and was not statistically significant. This study has found that radiation exposure and possible exposure to circulating metal ions as a result of routine instrumented spine surgery in children since 1979 is not associated with an increased risk of cancer in up to 36 years of follow up. 2.

One-Way Self-Expanding Rod for Early-Onset Scoliosis: A Prospective Observational Study of 20 Patients

Background: Progressive early-onset scoliosis (EOS) raises major challenges for surgeons, as growth must be preserved. With conventional growing rods, the need for repeated surgery for rod lengthening is associated with numerous complications, high costs, and a heavy psychosocial burden on the patient and family. We assessed the safety and efficacy of a new One-Way Self-Expanding Rod (OWSER). Methods: This prospective single-centre phase 2 study included two groups of children with progressive EOS treated by the OWSER in 2016-2017: ten received a unilateral construct to treat progressive non-neuromuscular curves and ten others a bilateral construct for neuromuscular scoliosis. Clinical and radiological data were assessed at surgery then 3, 6, 12, and 18 months later. The primary endpoint was success defined as absence of repeated surgery or Cobb angle progression <15° at 12 months. Findings: In the non-neuromuscular group, rod expansion occurred in 50% of patients [95CI, 19-81]; in the 5 other patients, rotational conflict at the flat part of the rod prevented rod expansion, 4 of them required surgery within the first 12 months. Rod expansion occurred spontaneously and during monthly traction sessions in all ten neuromuscular patients [95%CI, 69-100], without mechanical or device-related complications, and residual pelvic obliquity was improved by -3° [-6·0 to 9·5] at 18 months. Lung function improved in the non-neuromuscular group. Interpretation: Used in a bilateral construct, the OWSER seems safe and less aggressive than traditional growing rods. It should avoid further surgery and reduce the complication rate. The bilateral construct seemed effective in correcting EOS in our small sample. The OWSER may be the treatment of choice for progressive spinal deformities in skeletally immature children. Trial Registration: ClinicalTrials.gov: NCT02266667. Funding Statement: Euros Company, SAS. Declaration of Interests: LM received grant and research support from Euros Company SAS and is a co-designer of the device. All other authors declare that they have no conflicts of interest. Ethics Approval Statement: All parents or guardians provided written informed consent. The study protocol was sponsored by the Assistance Publique-Hopitaux de Paris and approved by the appropriate ethics committee (Comite de Protection des Personnes Ile-de France 2, n° 2014-06-10) and Agence Nationale de Securite du Medicament (ANSM, DMTCOS/DMCHIR/LAB/2014-A01043-44-A).

Serial Casting in Neuromuscular and Syndromic Early-onset Scoliosis (EOS) Can Delay Surgery Over 2 Years.

The primary goal in managing early-onset scoliosis (EOS) is delaying/preventing surgical intervention while allowing improved spinal growth and chest wall and lung development to improve life expectancy. The effectiveness of serial casting for patients with neuromuscular and syndromic EOS is unclear. Patients from 2 multicenter registries who underwent serial casting for nonidiopathic scoliosis (NIS) were reviewed retrospectively. Comparisons were made between precasting and postcasting major and compensatory curves and spine height. The need for surgical intervention and any treatment complications were documented. Risk factors for major curve progression from baseline to casting cessation were evaluated via univariate analysis. Forty-four patients (23 females; 21 males) with NIS (26 syndromic, 18 neuromuscular) and a mean age of 3.2 years at baseline were included. Mean follow-up and casting duration was 3.9 and 2.0 years, respectively. There were no statistically significant differences between mean precasting and postcasting major curve (55 vs. 60 degrees; P=0.348), minor curve (31 vs. 33 degrees; P=0.510), or rib-vertebra angle difference (18 vs. 29 degrees; P=0.840). However, thoracic height (15.5 vs. 16.8 cm; P=0.031) and lumbar height (8.9 vs. 9.8 cm; P=0.013) were significantly greater upon casting cessation. Currently, 13 patients (30%) have had successful casting (improvement of major curve ≥10 degrees) while 24 patients (55%) experienced major curve progression (worsening), and 19 patients (43%) required surgical intervention. Mean time from first casting to surgery was 34.5±15.1 months. There were no statistically significant predictors for major curve progression on univariate analysis. Spinal deformity progression despite casting and the subsequent need for surgical intervention for NIS were significantly higher compared with those reported for idiopathic EOS. However, serial casting did afford a substantial delay in surgical intervention. Ultimately, serial casting for neuromuscular or syndromic EOS is an effective strategy for delaying surgical intervention, despite suboptimal radiographic outcomes. Level III.

Skip constructs in spinal muscular atrophy: outcomes of a novel approach for posterior spinal instrumentation and fusion.

Many children with spinal muscular atrophy (SMA) develop progressive spinal deformity, worsening already compromised pulmonary function and global spinal balance. Early results demonstrate that intrathecal administration of nusinersen, a recent FDA-approved drug, improves motor function and ventilator-free survival, necessitating preservation of intrathecal access when considering PSIF. The purpose of this study is to assess medium-term outcomes of a specialized approach for posterior spinal instrumentation and fusion (PSIF) to preserve intrathecal access in patients with SMA. A retrospective review of patients with SMA undergoing PSIF at a single tertiary academic medical center during a 3-year period was completed. To facilitate intrathecal drug administration, the traditional approach to PSIF was modified to "skip" one or more intervertebral levels at the thoracolumbar junction. Clinical notes and radiographs were reviewed for postoperative outcomes including major coronal curve correction and complications, including loss of correction, hardware failure and surgical revision. Eight patients were identified, with a mean age of 12.7 ± 1.6years and follow-up of 4years. These patients had a mean preoperative major coronal curve of 56.4°, with mean curve correction of 35.2°. At follow-up, no patients experienced rod breakage, loss of correction, or postoperative chronic pain. Only one patient required revision surgery due to bony overgrowth at the skipped level after three and a half years. Implementing the skip construct approach for PSIF in patients with SMA allows for scoliosis correction without compromising intrathecal drug delivery. Follow-up at 4years reveals no adverse clinical events, hardware failure or loss of correction. IV.

Of Major Complication Types, Only Deep Infections After Spinal Fusion Are Associated With Worse Health-related Outcomes in Children With Cerebral Palsy.

Retrospective review. The aim of this study was to determine whether major postoperative complications ("complications") are associated with 2-year improvements in Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) scores after scoliosis surgery, and whether complications and preoperative characteristics predict 2-year improvements in CPCHILD Total score. Spinal arthrodesis can halt the progression of spinal deformity in patients with cerebral palsy (CP)-related scoliosis. However, these patients are prone to postoperative complications. Using a multicenter CP registry, we identified 222 patients aged ≤21 years who underwent spinal fusion from 2008 to 2015 and had ≥2-year follow-up. We compared CPCHILD score improvement between 71 patients who had 1 or more complications ("complications group") versus 151 who did not ("no-complications group"). Complications were deep infections, thromboembolic events, and cardiopulmonary, gastrointestinal, and neurologic complications. Multiple linear regression was used to identify predictors of 2-year postoperative CPCHILD score improvement (alpha = 0.05). At 2-year follow-up, the complications group had similar mean improvement in CPCHILD score across all domains compared with the no-complications group (P > 0.05). When stratifying by complication type, deep infection was associated with less improvement in CPCHILD Comfort and Emotions (P = 0.02), Quality of Life (P < 0.01), and Total (P = 0.04) scores. When controlling for Gross Motor Function Classification System subcategory, age, and body mass index, only preoperative CPCHILD Total score and postoperative deep infection (F[4, 176] = 14; P < 0.0001; R = 0.24) predicted 2-year improvement in CPCHILD Total score. Higher preoperative Total score and postoperative deep infection independently predicted less improvement in Total score. Postoperative deep infection and higher preoperative CPCHILD Total score independently predicted less improvement in CPCHILD Total score. Other major postoperative complications were not associated with differences in 2-year postoperative improvements in CPCHILD scores across all domains. 3.

Spine deformities in patients with cerebral palsy; the role of the pelvis.

IntroductionProgressive neuromuscular spinal deformities with pelvic obliquity and loss of sitting balance are typical features of severely affected patients with cerebral palsy. The pelvis represents the key bone between the spine and the lower extremity when it comes to deciding whether and when to operate and if spine or hip surgery first is beneficial. The pelvis can be looked at as the lowest vertebra and as the rooftop of the lower extremities.Biomechanical considerationsTo allow for a normal spinal shape, the pelvis needs to be horizontal in the frontal plane and mildly anterior tilted in the sagittal plane, less for sitting and more for standing. Any abnormal pelvic position requires spinal compensation and challenges the equilibrium control of the individual. Both anatomical neighbourhoods – the spine and the hip joints — have to be considered when spinal deformities, hip instability and contractures evolve, in conservative therapy (bracing, physiotherapy, seating in the wheelchair) and when surgical interventions are weighed out against each other.Surgical considerationsMultiple anatomical factors such as sagittal profile and pelvic orientiation, pelvic transverse plane asymmetries and lumbosacral malformations have to be considered in case the pelvis is instrumented with sacral and iliac screws. Rotational deformities and asymmetries of the pelvic bones make the safe insertion of long screws challenging. Advantages of primary pelvic fixation include correction of pelvic obliquity, especially considering the lever arm of the whole spinal construct. The risk of revision surgery due to progression of distal curves is also reduced. Disadvantages of pelvic fixation include the complexity of the additional intervention, which may result in longer operating times, increased risk of blood loss, infection and hardware malpositioning.

Risk factor analysis for progressive spinal deformity after resection of intracanal tumors\u2500 a retrospective study of 272 cases

BackgroundProgressive spinal deformity has become a well-recognized complication of intracanal tumors resection. However, the factors affecting post-operative spinal stability remain to be further research. Here, we described the current largest series of risk factors analysis for progressive spinal deformity following resection of intracanal tumors.MethodsWe retrospectively analyzed the medical records of the patients with resection of intracanal tumors between January 2009 and December 2018. All patients who underwent resection of intracanal tumors performed regular postoperative follow-up were identified and included in the study. Clinical, radiological, surgical, histopathological, and follow-up data were collected. The incidence of postoperative progressive kyphosis or scoliosis was calculated. The statistical relationship between postoperative progressive spinal deformity and radiographic, clinical, and surgical variables was assessed by using univariate tests and multivariate logistic regression analysis.ResultsTwo hundred seventy-two patients (mean age 42.56 ± 16.18 years) with median preoperative modified McCormick score of 3 met the inclusion criteria. Among them, 7(2.6%)patients were found to have spinal deformity preoperatively, and the extent of spinal deformity in these 7 patients deteriorated after surgery. 36 (13.2%) were new cases of postoperative progressive deformity. The mean duration of follow-up was 21.8 months (median 14 months, range 6–114 months). In subsequent multivariate logistic regression analysis, age ≤ 18 years (p = 0.027), vertebral levels of tumor involvement (p = 0.019) and preoperative spinal deformity(p = 0.008) was the independent risk factors (p < 0.05), increasing the odds of postoperative progressive spinal deformity by 3.94-, 0.69- and 27.11-fold, respectively.ConclusionsThe incidence of postoperative progressive spinal deformity was 15.8%, mostly in these patients who had younger age (≤18 years), tumors involved in multiple segments and preoperative spinal deformity. The risk factors of postoperative progressive spinal deformity warrants serious reconsideration that when performing resection of spinal cord tumors in these patients with such risk factors, the surgeons should consider conducting follow-ups more closely, and when patients suffering from severe symptoms or gradually increased spinal deformity, surgical spinal fusion may be a more suitable choice to reduce the risk of reoperation and improve the prognosis of patients.

Pedicle screw instrumentation with or without pelvic fixation in neuromuscular scoliosis: Outcome and complications in a series of 37 patients with a minimum 2-year follow-up

ObjectiveNeuromuscular scoliosis (NMS) is often associated with rapid progressive spinal deformities. Indications, when to extend the instrumentation to the pelvis for pelvic obliquity are not generally accepted at this time. This study reports on the indications, surgical technique and results using pedicle screw instrumentation exclusively with or without pelvic fixation for spine fusion in patients with NMS. Patients and methodsThirty-seven NMS patients were treated with pedicle screw instrumentation (PSI) between 2007 and 2013 with a minimum follow-up of 24 months. The mean age at the time of operation was 14.91 ± 2.03 years (range, 11.17–18.58). Posterior spine fusion (PSF) was conducted in 33 patients; 4 patients underwent a combined anterior spinal release followed by PSF during one-stage surgery. Pelvic fixation was achieved by ilium screws combined with S-1 screws in 4 cases and by sacral-alar-iliac (SAI) technique by Sponseller in 9 cases, respectively. ResultsThe mean primary Cobb angle was 65.5° (range, 14–103°) and improved significantly to 19.8° (range, 1–50°, p < 0.001) after surgery and 20.5° (range, 3–57, p = 0.47) at 2 years FU, respectively. Besides, an improvement of pelvic obliquity and T1 tilt angle could be detected. Major complications occurred in 19% and minor complications in 32%. ConclusionPedicle screw fixation only for spine fusion in patients with NMS can be applied safely with reasonable complication rates. An excellent correction in all planes, a significant improvement of the pelvic obliquity and almost no loss of correction at 2 years FU were observed.

Spinal growth tethering: indications and limits.

The standard of care for progressive spinal deformity that is greater than 45-50 degrees in growing children is deformity correction with spinal fusion and instrumentation. This sacrifice both spinal motion and further spinal growth of the fused region. Idiopathic scoliosis in particular is associated with disproportionate anterior spinal column length compared to the posterior column (hypokyphosis) that is associated with the coronal (scoliosis) and axial plane (rib and lumbar prominence) deformities. In theory, application of compression to the convex and anterior aspects of vertebrae could decrease both anterior and lateral growth via the Hueter-Volkmann principle, while allowing growth on the concave and posterior aspect resulting in spinal realignment created by altered growth. Animal models and preliminary clinical experience suggest spinal growth can be modulated in this way using a flexible tether applied to the convex side of scoliotic vertebral column. Experimental studies suggest disc health is preserved with a flexible tether as disc motion is maintained during the growth period. Anterolateral tethering been performed via a thoracoscopic spinal approach clinically for a number of years and the early clinical outcomes are beginning to appear in the literature. Initial results of anterolateral tethering in growing patients with spinal deformities are encouraging, however the results 3-4 years after the procedure are somewhat mixed. Further research is ongoing and many remain optimistic that improvements in technology and understanding will continue to lead to better patient outcomes.

Relationship of Scoliosis with Pain and Respiratory Dysfunction in Patients with Duchenne Muscular Dystrophy

Abstract Introduction Scoliosis is one of the major causes of respiratory dysfunction in patients with Duchene muscular dystrophy (DMD). Also, progressive spinal deformity severely affects walking and sitting, and can also lead to pain and difficulty in patient care. Although the relationship between scoliosis and respiratory functions was extensively studied, its impact on pain has not been examined. Hereby, we aimed to evaluate the relationship between scoliosis and respiratory dysfunction and pain, together with the frequency of scoliosis in Turkish DMD patients. Materials and Methods The demographical data, rate, and region of scoliosis, pain, and respiratory functions were evaluated in 69 male DMD patients. The severity of pain was evaluated with a visual analog scale (VAS) and the degree of scoliosis was assessed with Cobb angle. Forced vital capacity was used to grade the pulmonary functions. Results Scoliosis was present in 52.2% of the patients, mainly in the dorsolumbar region. Pain was present in 53.6% of the patients, most commonly in the back and lumbar regions. The rate of pulmonary dysfunction was 49.3%. Of the 36 patients with scoliosis, prevalences of pain and respiratory dysfunction were 77.7 and 50.0%, respectively. Scoliosis was significantly associated with pain and respiratory dysfunction, as expected. Conclusion The prevalence of pain and respiratory dysfunction is considerably high in DMD patients with scoliosis. These patients should be closely monitored for pain and deterioration in respiratory functions, to ease their daily care, increase their quality of life, and preserve the functionality, as long as possible.

Complications associated with cement augmentation techniques in spinal surgery

Metabolic conditions can compromise the integrity of the spine, placing patients at risk of pain, progressive spinal deformity, and failure of instrumentation used in treatment of spinal pathology. Vertebroplasty, kyphoplasty, sacroplasty, and augmented pedicle screws are frequently performed procedures developed to help combat these issues. These procedures are infrequently associated with significant issues, but serious complications from these surgeries can occur. Consequently, it is critical that treating surgeons be aware of the most common complications associated with cement augmentation procedures, as well as understand how to minimize their occurrence, diagnose them swiftly, and manage them appropriately when needed.

Posterior Correction Techniques for Adolescent Idiopathic Scoliosis.

Adolescent idiopathic scoliosis represents a complex, three-dimensional deformity of the spine. Posterior spinal fusion is commonly performed in severe cases to avoid the long-term adverse sequelae associated with progressive spinal deformity. The goals of spinal fusion include halting the progression of deformity, optimizing spinal balance, and minimizing complications. Recent advances in short-segment spinal fixation have allowed for improved three-dimensional deformity correction. Preoperative planning and assessment of spinal flexibility is essential for successful deformity correction and optimization of long-term outcomes. Judicious use of releases and/or spinal osteotomies may allow for increased mobility of the spine but are associated with increased surgical time, blood loss, and risk of complications. Appreciation of implant design and material properties is critical for safe application of correction techniques. Although multiple reduction techniques have been described, no single technique is optimal for every patient.

A Differential Hypofunctionality of G\u03b1i Proteins Occurs in Adolescent Idiopathic Scoliosis and Correlates with the Risk of Disease Progression

Adolescent idiopathic scoliosis is the most prevalent spine deformity and the molecular mechanisms underlying its pathophysiology remain poorly understood. We have previously found a differential impairment of melatonin receptor signaling in AIS osteoblasts allowing the classification of patients into three biological endophenotypes or functional groups (FG1, FG2 and FG3). Here, we provide evidence that the defect characterizing each endophenotype lies at the level of Gαi proteins leading to a systemic and generalized differential impairment of Gi-coupled receptor signaling. The three Gαi isoforms exhibited a selective serine phosphorylation patterns for each AIS endophenotype resulting in a differential reduction in Gαi protein activity as determined by cellular dielectric spectroscopy and small interfering RNA methods. We found that one endophenotype (FG2) with phosphorylated Gαi1 and Gαi2 was consistently associated with a significantly high risk of spinal deformity progression when compared to the other two endophenotypes (FG1 and FG3). We further demonstrated that each endophenotype is conserved among affected family members. This study expands our understanding of the mechanism underlying the Gi-coupled receptor signaling dysfunction occurring in AIS and provides the first evidence for its hereditary nature. Collectively, our findings offers a new perspective on Gαi hypofunctionality in a human disease by revealing specific serine phosphorylation signatures of Gαi isoforms that may facilitate the identification of AIS patients at risk of spinal deformity progression.

Surgical "no-touch" distraction technique to correct pediatric scoliosis

Reduction and retention of the scoliotic curve in children with progressive spinal deformities. Progressive neuromyopathic scoliosis which cannot be controlled conservatively (especially by walking disability), and/or development of athorax insufficiency syndrome (TIS). Insufficient soft tissue coverage; body weight < 11.4 kg; body mass index (BMI) > 25 or >50 kg; missing osseous anchoring structures (ribs); adult skeleton (usually age < 12years at surgery); severe spasticity. Indirect correction and distraction of the spinal deformity by two extendable, paravertebral telescopic implants, anchored to the cranial ribs and the iliac crest; the spine is not compromised surgically. Early functional therapy, no brace; multiple surgical (VEPTR®-system) or externally (magnetically controlled rods) controlled extensions per year. The surgical paravertebral "no-touch" technique for spine correction is particularly suitable for children with neuromyopathic scoliosis with abody weight > 11.4 kg. Our prospective group of children (n = 45), was treated with acombination of the classic vertical expandable prosthetic titanium rib (VEPTR®) anchored to the ribs and iliac crest combined with amagnetically controlled telescopic implant (MAGEC®). The primary correction of >50% was achieved, while progression was effectively prevented over years. In 495 outpatient lengthening procedures, the rate of implant-associated complications requiring surgery was 3.7%. Of the 45children, 13 (29%) underwent surgical revision. With the proposed surgical "no-touch" technique for scoliosis correction of pediatric neuromyopathic deformities, an effective reduction of the scoliotic curve can be achieved and maintained. Advantages of the method are apartial retention of spinal flexibility and areduction of spinal ossifications, which facilitates dorsal spondylodesis as the final treatment.

High Correlation Between Achieved and Expected Distraction Using Magnetically Controlled Growth Rods (MCGR) With Rib to Pelvis Fixation in Pediatric Spine Deformity.

Magnetically controlled implant systems have been established to treat severe progressive spinal deformity in children. The purpose of this study was to evaluate (1) the ratio between achieved and expected distraction length, (2) the complication rate and its risk factors as well as (3) the correlation of the distraction length and the length of the spine. A total of 40 patients with an average follow-up of 34 (14 to 57) months were prospectively included in the study. Children underwent lengthening procedures every three months. The ratio between the distraction lengths was determined by comparing the measured distraction length of the rod on radiographs with the distraction length displayed on the external remote controller for the magnetically controlled growing rod (MCGR). Age, weight, height, and complications were repeatedly recorded. The analysis of 746 procedures showed the actual distraction to be 94.4% of the expected one. No difference between implants on the concave and convex spinal side was observed. The overall complication rate was 4.6% mainly because of failure of the implant or lack of implant extension, which was directly related to an increased BMI. There was also a strong correlation between achieved implant distraction length and gain in spinal length. Our study demonstrates a high ratio (0.94) between achieved and expected distraction length of magnetically controlled spinal rods. The complication rate was low (4.6%) and correlated to a high BMI. The correlation between the achieved implant distraction length and spinal length indicates the efficiency of the MCGR therapy. Therapeutic Level IV.

Outcome analysis of surgery for symptomatic spinal metastases in long-term cancer survivors.

As patients with metastatic cancer live longer, an increased emphasis is placed on long-term therapeutic outcomes. The current study evaluates outcomes of long-term cancer survivors following surgery for spinal metastases. The study population included patients surgically treated at a tertiary cancer center between January 2010 and December 2015 who survived at least 24 months postoperatively. A retrospective chart and imaging review was performed to collect data regarding patient demographics; tumor histology; type and extent of spinal intervention; radiation data, including treatment dose and field; long-term sequelae, including local tumor control; and reoperations, repeat irradiation, or postoperative kyphoplasty at a previously treated level. Eighty-eight patients were identified, of whom 44 were male, with a mean age of 61 years. The mean clinical follow-up for the cohort was 44.6 months (range 24.2-88.3 months). Open posterolateral decompression and stabilization was performed in 67 patients and percutaneous minimally invasive surgery in 21. In the total cohort, 84% received postoperative adjuvant radiation and 27% were operated on for progression following radiation. Posttreatment local tumor progression was identified in 10 patients (11%) at the index treatment level and 5 additional patients had a marginal failure; all of these patients were treated with repeat irradiation with 5 patients requiring a reoperation. In total, at least 1 additional surgical intervention was performed at the index level in 20 (23%) of the 88 patients: 11 for hardware failure, 5 for progression of disease, 3 for wound complications, and 1 for postoperative hematoma. Most reoperations (85%) were delayed at more than 3 months from the index surgery. Wound infections or dehiscence requiring additional surgical intervention occurred in 3 patients, all of which occurred more than a year postoperatively. Kyphoplasty at a previously operated level was performed in 3 cases due to progressive fractures. Durable tumor control can be achieved in long-term cancer survivors surgically treated for symptomatic spinal metastases with limited complications. Complications observed after long-term follow-up include local tumor recurrence/progression, marginal tumor control failures, early or late hardware complications, late wound complications, and progressive spinal instability or deformity.