Biomechanical Analysis of the Tuning Fork Plate Versus Dual Pelvic Screws in a Sacrectomy Model: A Finite Element Study.

STUDY DESIGN: To evaluate the mechanical effectiveness of "tuning fork" plate fixation system by comparing with dual iliac screw fixation under different spinal motion through finite element analysis (FEA). OBJECTIVE: Lumbosacral deficiencies occur from birth defects or following destruction by tumors. The objective of this study was to evaluate the mechanical effectiveness of the tuning fork plate compared to dual iliac screw system which is the gold standard fixation in treating lumbosacral deficiencies. This is an innovative fixation device for treating lumbosacral deficiencies. METHODS: The deficiency model was prepared using a previously developed and validated finite element T10-pelvis model. To create the lumbo-sacral deficiency the segments between L3 and sacrum were removed from the model. The model was then instrumented from T10 to L2 segments and the ilium using either the tuning fork plate or a dual iliac screw construct. With the ilium fixed, the T10 vertebrae was subjected to 10 Nm moment and 400 N follower load to simulate spinal motions. Range of motion (ROM) of spine and stresses on the instrumentation were calculated for 2 fixation devices and compared with each other. RESULTS: The 2 fixation systems demonstrate a comparable motion reduction in all loading modes. Stress values were higher in the dual iliac screw constructs compared with the tuning fork plate fixation system. The factor of safety of the tuning fork plate device was higher than the dual iliac screw fixation by 50%. CONCLUSIONS: Both fixation devices had similar performance in motion reduction at spine levels. However, based on predicted implant stresses there were less chances of implant failure in the fork plate fixation, compared to the dual iliac screw system.

Correlation of Computational Instantaneous Wave-Free Ratio With Fractional Flow Reserve for Intermediate Multivessel Coronary Disease.

This study computationally assesses the accuracy of an instantaneous wave-free ratio (iFR) threshold range compared to standard modalities such as fractional flow reserve (FFR) and coronary flow reserve (CFR) for multiple intermediate lesions near the left main (LM) coronary bifurcation. iFR is an adenosine-independent index encouraged for assessment of coronary artery disease (CAD), but different thresholds are debated. This becomes particularly challenging in cases of multivessel disease when sensitivity to downstream lesions is unclear. Idealized LM coronary arteries with 34 different intermediate stenoses were created and categorized (Medina) as single and multiple lesion groups. Computational fluid dynamics modeling was performed with physiologic boundary conditions using an open-source software (simvascular1) to solve the time-dependent Navier-Stokes equations. A strong linear relationship between iFR and FFR was observed among studied models, indicating computational iFR values of 0.92 and 0.93 are statistically equivalent to an FFR of 0.80 in single and multiple lesion groups, respectively. At the clinical FFR value (i.e., 0.8), a triple-lesion group had smaller CFR compared to the single and double lesion groups (e.g., triple = 3.077 versus single = 3.133 and double = 3.132). In general, the effect of additional intermediate downstream lesions (minimum lumen area > 3 mm2) was not statistically significant for iFR and CFR. A computational iFR of 0.92 best predicts an FFR of 0.80 and may be recommended as threshold criteria for computational assessment of LM stenosis following additional validation using patient-specific models.

Spinal Deformity in Sotos Syndrome: First Results of Growth-friendly Spine Surgery.

BACKGROUND: Sotos syndrome (SS), or cerebral gigantism, describes children with macrocephaly, craniofacial abnormalities, general overgrowth, ligamentous laxity, developmental delay, and neurological disabilities. Fewer than 500 cases have been reported since Sotos and colleagues described the condition in 1964 and no literature exists on the management of spinal deformity in children under 10 years old.The aims of this study were: (1) to characterize the presentation of spinal deformities in patients with SS; and (2) to provide preliminary results of growth-friendly instrumentation (GFI) in these children. METHODS: Thirteen children (9 boys) with SS and minimum of 2-year follow-up were identified from 2 multicenter early-onset scoliosis (EOS) databases (1997-2017). Mean age at index surgery and follow-up duration were 5.0 years (range, 1.8 to 10 y) and 7.2 years (range, 2.1 to 14.9 y), respectively. Patients underwent GFI for a mean of 5.7 years (range, 2 to 10.2 y), with an average of 9 lengthenings (range, 2 to 18). Definitive spinal fusion was performed in 4 patients (31%). Major curve magnitude, T1-T12 and T1-S1 lengths, thoracic kyphosis, and lumbar lordosis were evaluated preindex, postindex, latest GFI, and postfusion, when possible. RESULTS: Five thoracolumbar (38%), 4 double major (31%), 2 main thoracic (15%), and 2 double thoracic curves (15%) were seen that spanned a mean of 6.8 levels (5 to 9). Major curves improved 36% (range, 5% to 71%), from a mean of 71 degrees (range, 48 to 90 degrees) to 46 degrees (range, 20 to 73 degrees) postindex surgery (P<0.001). Major curves remained stable at a mean of 52 degrees (range, 20 to 87 degrees) at latest GFI (P=0.36). True T1-T12 and T1-S1 growth velocities during GFI were 0.5 mm/mo (range, 0.4 to 0.8 mm/mo) and 0.8 mm/mo (range, 0.1 to 2.1 mm/mo), respectively. Twenty-six complications occurred in 9 patients (69%) averaging 2 complications per patient (range, 0 to 7). CONCLUSIONS: This is the first study to evaluate the outcomes of GFI in children with SS and EOS. Compared with published data for outcomes of GFI in EOS, children with SS may have less major curve correction. Growth-friendly surgery remains an effective treatment method for EOS in patients with SS. LEVELS OF EVIDENCE: Level IV-retrospective case-series.

Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years.

STUDY DESIGN: Retrospective observational study of a continuous series of 28 children. PURPOSE: To determine the mechanical failure rate in our cohort of children treated with magnetically controlled growth rods (MCGRs). OVERVIEW OF LITERATURE: Previous studies report a MCGR mechanical failure rate of 0%-75%. METHODS: All patients with MCGR implantation between 2012 and 2015 were examined and followed up for a minimum of 2 years. A retrospective evaluation of contemporaneously documented clinical findings was conducted, and radiographs were retrospectively examined for mechanical failure. The external remote controller (ERC)-specified length achieved in the clinic was compared to the length measured on subsequent radiographs. RESULTS: Fourteen mechanical failures were identified in 28 children (50%) across a total of 52 rods (24 pairs and four single constructs). Mechanical failures were due to: failure to lengthen under general anesthesia (seven children), actuator pin fracture (four), rod fracture (one), foundation screw failure (one), and ran out of rod length (one). Of the 14 mechanical failures, six were treated with final fusion operations (reflecting limited further growth potential), and eight patients were treated with the intention for further lengthening. We therefore consider these eight patients to represent the true incidence of mechanical failure in our cohort (29%). The difference between the ERC length and radiographic length was found to be identical in 11% cases; 35% were overestimates, and 54% were underestimates. The median underestimate was 2.45 mm whereas the median overestimate was 3.1 mm per distraction episode. In total, 95% of all ERC distractions were within ±10 mm of the radiographic length achieved over a median of nine distraction episodes. CONCLUSIONS: Our series is the most comprehensive MCGR series published to date, and we present a mechanical failure rate of 29%. Clinicians should be mindful of the discrepancies between ERC length and radiographic measurements of rod length; other modalities may be more helpful in this regard.

Long-Term Outcomes of Patent Foramen Ovale Closure or Medical Therapy after Stroke.

BACKGROUND: Whether closure of a patent foramen ovale reduces the risk of recurrence of ischemic stroke in patients who have had a cryptogenic ischemic stroke is unknown. METHODS: In a multicenter, randomized, open-label trial, with blinded adjudication of end-point events, we randomly assigned patients 18 to 60 years of age who had a patent foramen ovale (PFO) and had had a cryptogenic ischemic stroke to undergo closure of the PFO (PFO closure group) or to receive medical therapy alone (aspirin, warfarin, clopidogrel, or aspirin combined with extended-release dipyridamole; medical-therapy group). The primary efficacy end point was a composite of recurrent nonfatal ischemic stroke, fatal ischemic stroke, or early death after randomization. The results of the analysis of the primary outcome from the original trial period have been reported previously; the current analysis of data from the extended follow-up period was considered to be exploratory. RESULTS: We enrolled 980 patients (mean age, 45.9 years) at 69 sites. Patients were followed for a median of 5.9 years. Treatment exposure in the two groups was unequal (3141 patient-years in the PFO closure group vs. 2669 patient-years in the medical-therapy group), owing to a higher dropout rate in the medical-therapy group. In the intention-to-treat population, recurrent ischemic stroke occurred in 18 patients in the PFO closure group and in 28 patients in the medical-therapy group, resulting in rates of 0.58 events per 100 patient-years and 1.07 events per 100 patient-years, respectively (hazard ratio with PFO closure vs. medical therapy, 0.55; 95% confidence interval [CI], 0.31 to 0.999; P=0.046 by the log-rank test). Recurrent ischemic stroke of undetermined cause occurred in 10 patients in the PFO closure group and in 23 patients in the medical-therapy group (hazard ratio, 0.38; 95% CI, 0.18 to 0.79; P=0.007). Venous thromboembolism (which comprised events of pulmonary embolism and deep-vein thrombosis) was more common in the PFO closure group than in the medical-therapy group. CONCLUSIONS: Among adults who had had a cryptogenic ischemic stroke, closure of a PFO was associated with a lower rate of recurrent ischemic strokes than medical therapy alone during extended follow-up. (Funded by St. Jude Medical; RESPECT ClinicalTrials.gov number, NCT00465270 .).

Final Fusion After Growing-Rod Treatment for Early Onset Scoliosis: Is It Really Final?

BACKGROUND: Final fusion is thought to be the end point for patients with early onset scoliosis following treatment with the use of growing rods. But is it? The purpose of this study was to determine the incidence and cause of any reoperation after final fusion. METHODS: A multicenter database of patients with early onset scoliosis was retrospectively analyzed to identify patients treated with growing rods with a minimum of 2 years of follow-up after final fusion. All reoperations were recorded. Reoperation was defined as a return to the operating room for any complication related to the final fusion surgery or etiology of the spinal deformity. RESULTS: One hundred (84%) of 119 patients met the inclusion criteria: for 38 of the patients, the etiology of scoliosis was neuromuscular; for 31, syndromic; for 22, idiopathic; and for 9, congenital. The mean age at final fusion was 12.2 years (range, 8.5 to 18.7 years). The mean follow-up after final fusion was 4.3 years (range, 2 to 11.2 years). Twenty (20%) of the patients had 30 complications requiring reoperation (57 procedures). There was a mean of 1.5 complications per patient after final fusion. Eight patients with neuromuscular scoliosis, 8 with syndromic, 4 with idiopathic, and no patient with congenital scoliosis required reoperation. Nine (9%) of the patients experienced infection (33 reoperation procedures); 6 (6%) had instrumentation failure (8 procedures); 5 (5%) had painful or prominent instrumentation (6 procedures); 3 (3%) each had coronal deformity (3 procedures), pseudarthrosis (3 procedures), or sagittal deformity (3 procedures); and 1 (1%) had progressive crankshaft chest wall deformity requiring a thoracoplasty (1 procedure). CONCLUSIONS: A higher-than-anticipated percentage of patients treated with growing rods required unplanned reoperation following final fusion. Long-term follow-up after final fusion is necessary to determine true final results. Patients and parents need to be counseled regarding the possibility of further surgery after final fusion. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Image-based quantification of 3D morphology for bifurcations in the left coronary artery: Application to stent design.

BACKGROUND: Improved strategies for stent-based treatment of coronary artery disease at bifurcations require a greater understanding of artery morphology. OBJECTIVE: We developed a workflow to quantify morphology in the left main coronary (LMCA), left anterior descending (LAD), and left circumflex (LCX) artery bifurcations. METHODS: Computational models of each bifurcation were created for 55 patients using computed tomography images in 3D segmentation software. Metrics including cross-sectional area, length, eccentricity, taper, curvature, planarity, branching law parameters, and bifurcation angles were assessed using open-sources software and custom applications. Geometric characterization was performed by comparison of means, correlation, and linear discriminant analysis (LDA). RESULTS: Differences between metrics suggest dedicated or multistent approaches should be tailored for each bifurcation. For example, the side branch of the LCX (i.e., obtuse marginal; OM) was longer than that of the LMCA (i.e., LCXprox) and LAD (i.e., first diagonal; D1). Bifurcation metrics for some locations (e.g., LMCA Finet ratio) provide results and confidence intervals agreeing with prior findings, while revised metric values are presented for others (e.g., LAD and LCX). LDA revealed several metrics that differentiate between artery locations (e.g., LMCA vs. D1, LMCA vs. OM, LADprox vs. D1, and LCXprox vs. D1). CONCLUSIONS: These results provide a foundation for elucidating common parameters from healthy coronary arteries and could be leveraged in the future for treating diseased arteries. Collectively the current results may ultimately be used for design iterations that improve outcomes following implantation of future dedicated bifurcation stents. © 2015 Wiley Periodicals, Inc.

Benign Arterial Calcification on Screening Mammogram: A Marker for Coronary Artery Disease?

BACKGROUND: Studies have shown several risk factors for coronary artery disease (CAD), such as diabetes and hypertension, are associated with benign arterial calcifications (BACs) seen on screening mammograms. However, there are few studies examining the association of BACs with women who are diagnosed with CAD. The purpose of our study was to determine whether there is an association between BACs present on routine screening digital mammograms and the presence of CAD as documented on cardiac catheterization. METHODS: A retrospective chart review was performed on women aged ≥40 years who had undergone a digital screening mammogram within two years of also having a cardiac catheterization from 1999 to 2010. Mammograms were reviewed for the presence of BACs. Cardiac catheterizations were reviewed for the presence of CAD. Patients with BACs were compared with those without BACs by chi-squared or Wilcoxon rank sum tests. RESULTS: The final study cohort consisted of 198 patients with 101 patients having clinically significant cardiac vessel disease. Most patients (67.2%) did not have diabetes, while the majority was hypertensive (83.3%) and had hypercholesterolemia (80.8%). On multivariate analysis, history of smoking (p=0.003), hypercholesterolemia (p≤0.0001), and BACs (p=0.005) were significant predictors of CAD. In a second model, CAD on cardiac catheterization was a significant predictor of BACs found on mammography while a history of smoking was a negative predictor of BACs. CONCLUSIONS: BACs present on digital screening mammography, history of smoking and hypercholesterolemia were all significant predictors of CAD. Routine screening digital mammography could potentially assist in stratification of patients in consideration of CAD.

Deep Surgical Site Infection Following 2344 Growing-Rod Procedures for Early-Onset Scoliosis: Risk Factors and Clinical Consequences.

BACKGROUND: Deep surgical site infection may change the course of growing-rod treatment of early-onset scoliosis. Our goal was to assess the effect of this complication on subsequent treatment. METHODS: A multicenter international database was retrospectively reviewed; 379 patients treated with growing-rod surgery and followed for a minimum of two years were identified. Deep surgical site infection was defined as any infection requiring surgical intervention. RESULTS: Forty-two patients (11.1%; twenty-five males and seventeen females) developed at least one deep surgical site infection. The mean age at the initial growing-rod surgery was 6.3 years (range, 0.6 to 13.2 years) and the mean duration of follow-up was 5.3 years (range, 2.2 to 14.3 years). The mean interval between the initial surgery and the first deep surgical site infection was 2.8 years (range, 0.02 to 7.9 years). Ten (2.6%) of the 379 patients developed deep surgical site infection before the first lengthening. Twenty-nine patients (7.7%) developed the infection during the course of the lengthening procedures, and three patients (0.8%) developed it after final fusion surgery. Thirty (13.6%) of 221 patients with stainless-steel implants had at least one deep surgical site infection compared with twelve (8%) of 150 patients with titanium implants (p < 0.05). (The remaining patients were treated with chromium-cobalt implants.) Twenty-two (52.4%) of the forty-two patients with deep surgical site infection underwent implant removal, which was complete in thirteen and partial in nine. Growing-rod treatment was terminated in two patients with partial removal and six patients with complete removal. An increased risk of deep surgical site infection was associated with stainless-steel implants (odds ratio [OR] = 5.7), non-ambulatory status (OR = 2.9), and the number of revisions before the development of deep surgical site infection (OR = 3.3). Neuromuscular etiology and non-ambulatory status increased the possibility of implant removal to treat infection (p < 0.05). CONCLUSIONS: The prevalence of deep surgical site infection associated with growing-rod surgery is higher than that associated with standard pediatric spinal fusion (historical data). Non-ambulatory status, more revisions, and stainless-steel implants increased the risk of deep surgical site infection. After eight surgical procedures, the risk of deep surgical site infection increased to approximately 50%. When patients have implant removal, efforts should be made to retain one longitudinal implant to continue treatment. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Closure of patent foramen ovale versus medical therapy after cryptogenic stroke.

BACKGROUND: Whether closure of a patent foramen ovale is effective in the prevention of recurrent ischemic stroke in patients who have had a cryptogenic stroke is unknown. We conducted a trial to evaluate whether closure is superior to medical therapy alone in preventing recurrent ischemic stroke or early death in patients 18 to 60 years of age. METHODS: In this prospective, multicenter, randomized, event-driven trial, we randomly assigned patients, in a 1:1 ratio, to medical therapy alone or closure of the patent foramen ovale. The primary results of the trial were analyzed when the target of 25 primary end-point events had been observed and adjudicated. RESULTS: We enrolled 980 patients (mean age, 45.9 years) at 69 sites. The medical-therapy group received one or more antiplatelet medications (74.8%) or warfarin (25.2%). Treatment exposure between the two groups was unequal (1375 patient-years in the closure group vs. 1184 patient-years in the medical-therapy group, P=0.009) owing to a higher dropout rate in the medical-therapy group. In the intention-to-treat cohort, 9 patients in the closure group and 16 in the medical-therapy group had a recurrence of stroke (hazard ratio with closure, 0.49; 95% confidence interval [CI], 0.22 to 1.11; P=0.08). The between-group difference in the rate of recurrent stroke was significant in the prespecified per-protocol cohort (6 events in the closure group vs. 14 events in the medical-therapy group; hazard ratio, 0.37; 95% CI, 0.14 to 0.96; P=0.03) and in the as-treated cohort (5 events vs. 16 events; hazard ratio, 0.27; 95% CI, 0.10 to 0.75; P=0.007). Serious adverse events occurred in 23.0% of the patients in the closure group and in 21.6% in the medical-therapy group (P=0.65). Procedure-related or device-related serious adverse events occurred in 21 of 499 patients in the closure group (4.2%), but the rate of atrial fibrillation or device thrombus was not increased. CONCLUSIONS: In the primary intention-to-treat analysis, there was no significant benefit associated with closure of a patent foramen ovale in adults who had had a cryptogenic ischemic stroke. However, closure was superior to medical therapy alone in the prespecified per-protocol and as-treated analyses, with a low rate of associated risks. (Funded by St. Jude Medical; RESPECT ClinicalTrials.gov number, NCT00465270.).

Impact of localizing general medical teams to a single nursing unit.

BACKGROUND: Localization of general medical inpatient teams is an attractive way to improve inpatient care but has not been adequately studied. OBJECTIVE: To evaluate the impact of localizing general medical teams to a single nursing unit. DESIGN: Quasi-experimental study using historical and concurrent controls. SETTING: A 490-bed academic medical center in the midwestern United States. PATIENTS: Adult, general medical patients, other than those with sickle cell disease, admitted to medical teams staffed by a hospitalist and a physician assistant (PA). INTERVENTION: Localization of patients assigned to 2 teams to a single nursing unit. MEASUREMENTS: Length of stay (LOS), 30-day risk of readmission, charges, pages to teams, encounters, relative value units (RVUs), and steps walked by PAs. RESULTS: Localized teams had 0.89 (95% confidence interval [CI], 0.37-1.41) more patient encounters and generated 2.20 more RVUs per day (CI, 1.10-3.29) compared to historical controls; and 1.02 (CI, 0.46-1.58) more patient encounters and generated 1.36 more RVUs per day (CI, 0.17-2.55) compared to concurrent controls. Localized teams received 51% (CI, 48-54) fewer pages during the workday. LOS may have been approximately 10% higher for localized teams. Risk of readmission within 30 days and charges incurred were no different. PAs possibly walked fewer steps while localized. CONCLUSION: Localization of medical teams led to higher productivity and better workflow, but did not significantly impact readmissions or charges. It may have had an unintended negative impact on hospital efficiency; this finding deserves further study.

Identification of hemodynamically optimal coronary stent designs based on vessel caliber.

Coronary stent design influences local patterns of wall shear stress (WSS) that are associated with neointimal growth, restenosis, and the endothelialization of stent struts. The number of circumferentially repeating crowns N(C) for a given stent design is often modified depending on the target vessel caliber, but the hemodynamic implications of altering N(C) have not previously been studied. In this investigation, we analyzed the relationship between vessel diameter and the hemodynamically optimal N(C) using a derivative-free optimization algorithm coupled with computational fluid dynamics. The algorithm computed the optimal vessel diameter, defined as minimizing the area of stent-induced low WSS, for various configurations (i.e., N(C)) of a generic slotted-tube design and designs that resemble commercially available stents. Stents were modeled in idealized coronary arteries with a vessel diameter that was allowed to vary between 2 and 5 mm. The results indicate that the optimal vessel diameter increases for stent configurations with greater N(C), and the designs of current commercial stents incorporate a greater N(C) than hemodynamically optimal stent designs. This finding suggests that reducing the N(C) of current stents may improve the hemodynamic environment within stented arteries and reduce the likelihood of excessive neointimal growth and thrombus formation.

Percutaneous transvenous mitral annuloplasty: initial human experience with a novel coronary sinus implant device.

BACKGROUND: We assessed the safety and feasibility of permanent implantation of a novel coronary sinus mitral repair device (PTMA, Viacor Inc). METHODS AND RESULTS: Symptomatic (New York Heart Association class 2 or 3) patients with primarily functional mitral regurgitation (MR) were included. A diagnostic PTMA procedure was performed in the coronary sinus venous continuity. MR was assessed and the PTMA device adjusted to optimize efficacy. If MR reduction (> or =1 grade) was observed, placement of a PTMA implant was attempted. Implanted patients were evaluated with echocardiographic, quality of life, and exercise capacity metrics. Nineteen patients received a diagnostic PTMA study. Diagnostic PTMA was effective in 13 patients (MR grade 3.2+/-0.6 reduced to 2.0+/-1.0), and PTMA implants were placed in 9 patients. Four devices were removed uneventfully (7, 84, 197, and 216 days), 3 for annuloplasty surgery due to observed PTMA device migration and/or diminished efficacy. No procedure or device-related major adverse events with permanent sequela were observed in any of the diagnostic or implant patients. Sustained reductions of mitral annulus septal-lateral dimension from 3D echo reconstruction dimensions were observed (4.0+/-1.2 mm at 3 months). CONCLUSIONS: Percutaneous implantation of the PTMA device is feasible and safe. Acute results demonstrate a possibly meaningful reduction of MR in responding patients. Sustained favorable geometric modification of the mitral annulus has been observed, though reduction of MR has been limited. The PTMA method warrants continued evaluation and development.

Neurologic risk in growing rod spine surgery in early onset scoliosis: is neuromonitoring necessary for all cases?

STUDY DESIGN: Retrospective case series from a multicenter database. OBJECTIVE: To evaluate the risk of neurologic injury during growing rod surgeries and to determine whether intraoperative neuromonitoring is necessary for all growing rod procedures. SUMMARY OF BACKGROUND DATA: Although the use of growing rod constructs for early-onset spinal deformity has become a commonly accepted treatment, the incidence of neurologic events during growing rod surgeries remains unknown. METHODS: We reviewed data from a multicenter database on 782 growing rod surgeries performed in 252 patients. VEPTR devices and any constructs with rib attachments were excluded. A questionnaire was sent to all surgeons contributing cases requesting detailed information about all neurologic events associated with any growing rod surgery. RESULTS: There were 782 growing rod surgeries performed on 252 patients including 252 primary growing rod implantations, 168 implant exchanges, and 362 lengthenings. Five hundred sixty-nine of 782 (73%) cases were performed with neuromonitoring. Only one clinical injury occurred in the series, resulting in an injury rate of 0.1% (1/782). This deficit occurred during an implant exchange while attempting pedicle screw placement, and resolved within 3 months. There were 2 cases with neuromonitoring changes during primary implant surgeries (0.9%, 2/231), 1 change during implant exchanges (0.9%, 1/116), and 1 neuromonitoring change during lengthenings (0.5%, 1/222). The single monitoring change that occurred during a lengthening was in a child with an intracanal tumor who also had a monitoring change during the primary surgery. There are anecdotal cases (outside this study group series) of neuromonitoring changes during simple lengthenings in children with uneventful primary implantations. CONCLUSION: Based on our study, the largest reported series of growing rod surgeries, the rate of neuromonitoring changes during primary growing rod implantation (0.9%) and exchange (0.9%) justifies the use of intraoperative neuromonitoring during these surgeries. As there were no neurologic events in 361 lengthenings in patients with no previous neurologic events, the question may be raised as to whether intraoperative neuromonitoring is necessary for simple lengthenings in these patients. However, caution should be maintained when interpreting our results as anecdotal cases of neurologic changes from simple lengthenings do exist outside of this series.

The natural history of congenital scoliosis and kyphosis.

STUDY DESIGN: Review article. OBJECTIVE: To discuss natural history of congenital scoliosis and kyphosis. SUMMARY OF BACKGROUND DATA: Review of previously published literature on natural history of congenital spine deformities. METHODS: Medline and google search for congenital scoliosis, kyphosis, and kyphoscoliosis, congenital spine anomalies, deformities, and pathologies, and congenital vertebral anomalies, deformities, and pathologies was performed. RESULTS: Congenital vertebral anomalies have potential to progress and careful assessment and monitoring is essential and early intervention may be desirable. CONCLUSION: Congenital vertebral anomalies invariably result from disturbed asymmetric growth and can have serious consequences.

The role of peri-operative cell salvage in instrumented anterior correction of thoracolumbar scoliosis: a case-controlled study.

Anterior scoliosis surgery is associated with potentially high blood loss, usually requiring allogenic transfusion either intra- or post-operatively. Blood loss in this type of surgery has been shown to correlate with surgical and anaesthetic techniques. In our centre the development of specific anaesthetic techniques as well as the routine use of cell salvage has dramatically reduced the rates of allogenic blood transfusion. Specific indications for the use of the cell saver in anterior scoliosis surgery have not been well defined. Previous studies have commented on the benefit from re-infusion of salvaged autologous blood for orthopaedic patients in general, whilst others have shown a negligible advantage specifically in anterior thoraco-lumbar fusion surgery. We carried out a retrospective study of 137 consecutive patients, all of whom underwent instrumented anterior scoliosis correction between March 1999 and September 2004. A study group consisting of 104 patients in whom a cell saver was used was compared with a control group consisting of 33 patients who underwent anterior instrumentation without cell saver. There was no significant difference in the mean ages, extent of surgery and male to female ratio between groups. In the control group 39.4% of patients required allogenic blood transfusion, versus 6.7% in the study group; the difference is statistically significant (p < 0.0001). A significant difference was also noted in post-operative haemoglobin values. The mean post-operative haemoglobin was 9.6 g/dl in the control group, versus 10.2 g/dl in the study group (p = 0.007). Our experience confirms that re-infusion of salvaged autologous blood in anterior scoliosis surgery has a role in the minimisation of postoperative anaemia and allogenic transfusion requirements in this type of surgery.

Dual growing rod technique followed for three to eleven years until final fusion: the effect of frequency of lengthening.

STUDY DESIGN: Retrospective case review of children completing dual growing rod treatment at our institutions. Patients had a minimum of 2 years follow-up. OBJECTIVE: To identify the factors influencing dual growing rod treatment outcome followed to final fusion. SUMMARY OF BACKGROUND DATA: Published reports on dual growing rod technique results for early onset scoliosis demonstrate it to be safe and effective in curve correction and maintenance as well as in allowing spinal growth. METHODS: Between 1990 and 2003, 13 patients with no previous surgery and noncongenital curves underwent final fusion. All had preoperative curve progression over 10 degrees after unsuccessful nonoperative treatment. There were 10 females and 3 males. Average age was 6.6 +/- 2.9 years at initial surgery. There were 3 idiopathic, 1 nonspine congenital anomaly, and 9 syndromic patients. Analysis included age at initial surgery and final fusion, number and frequency of lengthenings, and complications. Radiographic evaluation included changes in Cobb angle, T1-S1 length, and instrumentation length over the treatment period. RESULTS: Cobb angle improved from 81.0 +/- 23 degrees to 35.8 +/- 15 degrees postinitial and 27.7 +/- 17 degrees after final fusion. Average number of lengthenings was 5.2 +/- 3 at an interval of 9.4 +/- 5 months. T1-S1 length increased from 24.4 +/- 3.4 to 29.3 +/- 3.6 cm postinitial and 35.0 +/- 3.7 cm postfinal fusion. Average growth was 1.46 +/- 0.66 cm/year. Those lengthened at

Infantile scoliosis in Beals syndrome: the use of a non-fusion technique for surgical correction.

Beals syndrome (congenital contractural arachnodactyl) is a genetic disorder of the connective tissue phenotypically related to Marfan syndrome. It is characterised by dolichostenomelia, arachnodactyly, multiple joint contractures, crumpled ears, hypoplastic muscles and scoliosis. The latter, the most important clinical feature of this rare condition, presents in the infantile and juvenile age group and has a tendency to rapid progression. Bracing often fails to control the scoliosis and surgery is the recommended treatment. We present our experience of two cases managed with the paediatric Isola instrumentation and a non-fusion technique.

Comparison of single and dual growing rod techniques followed through definitive surgery: a preliminary study.

STUDY DESIGN: Retrospective analysis of patients treated with single and dual growing rods who had completed their course of treatment, had definitive fusion, and had a minimum of 2 years follow-up. OBJECTIVES: To determine which technique was the most effective in the management of severe spinal deformity in young children: control of the spinal deformity, spinal growth, and the incidence of complications. SUMMARY OF BACKGROUND DATA: Growing rod techniques provide proximal and distal segmental "claw" foundations, but their overall results through definitive fusion have not been clearly determined. METHODS: A total of 28 consecutive patients who had growing rod procedures followed through definitive spinal fusions were analyzed. There were three patient groups: Group 1 (N = 5), single submuscular rod and short apical fusion; Group 2 (N = 16), single growing rod alone; and Group 3 (N = 7), dual growing rods. RESULTS: The interval between initial rod insertion and definitive spinal fusion was similar in all three groups. The best overall results occurred in Group 3, whereas the patients in Group 1 had the worse results. Both Groups 2 and 3 provided good initial correction of the spinal deformity and allowed spinal growth. Group 2 had better frontal and sagittal plane balance and the lowest complication rate. CONCLUSION: The use of growing rods is effective in controlling severe spinal deformities and allowing spinal growth. Dual rods are stronger than single rods and, therefore, provide better initial correction and maintenance of correction. The use of an apical fusion does not appear to be effective over the course of treatment.

Dual growing rod technique for the treatment of progressive early-onset scoliosis: a multicenter study.

STUDY DESIGN: A retrospective case review of children treated with dual growing rod technique at our institutions. Patients included had no previous surgery and a minimum of 2 years follow-up from initial surgery. OBJECTIVES: To determine the safety and effectiveness of the previously described dual growing rod technique in achieving and maintaining scoliosis correction while allowing spinal growth. SUMMARY OF BACKGROUND DATA: Historically, the growing rod techniques have used a single rod and the reported results have been variable. There has been no published study exclusively on the results of dual growing rod technique for early-onset scoliosis. METHODS: From 1993 to 2001, 23 patients underwent dual growing rod procedures using pediatric Isola instrumentation and tandem connectors. Diagnoses included infantile and juvenile idiopathic scoliosis, congenital, neuromuscular, and other etiologies. All had curve progression over 10 degrees following unsuccessful bracing or casting. Of 189 total procedures within the treatment period, 151 were lengthenings with an average of 6.6 lengthenings per patient. Analysis included age at initial surgery and final fusion (if applicable), number and frequency of lengthenings, and complications. Radiographic evaluation included measured changes in scoliosis Cobb angle, kyphosis, lordosis, frontal and sagittal balance, length of T1-S1 and instrumentation over the treatment period, and space available for lung ratio. RESULTS: The mean scoliosis improved from 82 degrees (range, 50 degrees-130 degrees) to 38 degrees (range, 13 degrees-66 degrees) after initial surgery and was 36 degrees (range, 4 degrees-53 degrees) at the last follow-up or post-final fusion. T1-S1 length increased from 23.01 (range, 13.80-31.20) to 28.00 cm (range, 19.50-35.50) after initial surgery and to 32.65 cm (range, 25.60-41.00) at last follow-up or post-final fusion with an average T1-S1 length increase of 1.21 cm per year (range, 0.13-2.59). Seven patients reached final fusion. The space available for lung ratio in patients with thoracic curves improved from 0.87 (range, 0.7-1.1) to 1.0 (range, 0.79-1.23, P = 0.01). During the treatment period, complications occurred in 11 of the 23 patients (48%), and they had a total of 13 complications. Four of these patients (17%) had unplanned procedures. Following final fusion, 2 patients required extensions of their fusions because of curve progression and lumbosacral pain. CONCLUSION: The dual growing rod technique is safe and effective. It maintains correction obtained at initial surgery while allowing spinal growth to continue. It provides adequate stability, increases the duration of treatment period, and has an acceptable rate of complication compared with previous reports using the single rod technique.