Long term follow-up of the tacrolimus in combination, tacrolimus alone compared (TICTAC) trial.

BACKGROUND: Tacrolimus (TAC) monotherapy has been compared to TAC and mycophenolate mofetil (MMF) in the randomized Tacrolimus in Combination, Tacrolimus Alone Compared (TICTAC) trial. Long term results are now reported. METHODS: Demographics are presented with descriptive statistics. Time to event was determined with Kaplan-Meier plots and Mantel-Cox Logrank statistics used to compare groups. RESULTS: One hundred and forty-seven (98 %) of the initial 150 TICTAC trial patients had long-term follow-up data available. The median follow-up was 13.4 years (interquartile range 7.2-15.1 years). Post-transplant survival at 5, 10 and 15 years in the TAC monotherapy group was 84.5 %, 66.9 %, and 52.7 %, and 94.4 %, 78.2 % and 56.1 % for patients randomized to TAC / MMF (p = 0.19 logrank). The freedom from cardiac allograft vasculopathy (≥grade 1) was 100 %, 87.5 %, 69.3 % and 46.5 % at 1, 5, 10 and 15 years in the monotherapy group and 100 %, 76.9 %, 68.1 % and 54.4 % in the TAC/MMF group respectively (p = 0.96 logrank). Crossover of treatment assignment did not alter these findings. The freedom from dialysis or renal replacement was 92.8 %, 84.2 % and 68.4 % for TAC monotherapy patients versus 100 %, 93.4 % and 82.3 % for TAC/MMF patients at 5, 10 and 15-years post-transplant (p = 0.15 logrank). CONCLUSIONS: Patients randomized to TAC/ MMF with 8-week steroid weaning had comparable outcomes to those with similar steroid regimen but discontinuation of MMF at 2 week post-transplant. The best outcomes were noted for patients initiated on TAC/ MMF including those where MMF was discontinued for intolerance. Both strategies are reasonable alternatives for patients post heart transplant. CONDENSED ABSTRACT: Tacrolimus monotherapy was compared to TAC and mycophenolate mofetil without long term steroids in the randomized Tacrolimus in Combination, Tacrolimus Alone Compared (TICTAC) trial. Post-transplant survival at 5, 10 and 15 years in the TAC monotherapy group was 84.5%, 66.9 %, and 52.7 %, and 94.4 %, 78.2 % and 56.1 % for patients randomized to TAC / MMF (p = 0.19 logrank). Cardiac allograft vasculopathy and kidney failure were similar between groups. Immunosuppression should be individualized to avoid over treating some patients while undertreating others.

A new flow cytometry assay identifies recipient IgG subtype antibodies binding donor cells: increasing donor availability for highly sensitised patients.

Objectives: There are four immunoglobulin (IgG) subtypes that have varying complement-activating ability: strong (IgG3 and IgG1) and weak (IgG2 and IgG4). The standard flow cytometric crossmatch (FCM) assay does not distinguish between the various subtypes of the IgG molecule. This study outlines the development and use of a novel cell-based IgG subtype-specific FCM assay that is able to detect the presence of and quantitate the IgG subtypes bound to donor cells. Methods: A six-colour lyophilised reagent was designed that specifically detects the four IgG subtypes, as well as distinguishes between T cells and B cells in the lymphocyte population. To test the efficacy of this reagent, a retrospective evaluation of a group of highly sensitised patients awaiting heart and kidney transplant was carried out, who, because of positive standard FCM results, had been deemed incompatible with numerous prior potential donors. Results: Observations in this study demonstrate that the positive standard FCM results were mainly because of the presence of noncomplement-activating IgG2 or IgG4 antibodies. The results were supported by the absence of C3d-binding donor-specific antibodies (DSA) and a negative complement-dependent cytotoxicity crossmatch (CDC). Conclusion: Preliminary data presented in this study demonstrate the reliability of the novel IgG subtype assay to detect the presence of pretransplant, complement-activating antibodies bound to donor cells. The knowledge gained from the IgG subtype assay and the C3d-binding specificities of DSAs provides improved identification of donor suitability in pretransplant patients, potentially increasing the number of transplants.

Primary stability of the Activ L® intervertebral disc prosthesis in cadaver bone and comparison of the keel and spike anchoring concept.

BACKGROUND: High primary stability is the key prerequisite for safe osseointegration of cementless intervertebral disc prostheses. The aim of our study was to determine the primary stability of intervertebral disc prostheses with two different anchoring concepts - keel and spike anchoring. METHODS: Ten ActivL intervertebral disc prostheses (5 x keel anchoring, 5 x spike anchoring) implanted in human cadaver lumbar spine specimens were tested in a spine movement simulator. Axial load flexion, extension, left and right bending and axial rotation motions were applied on the lumbar spine specimens through a defined three-dimensional movement program following ISO 2631 and ISO/CD 18192-1.3 standards. Tri-dimensional micromotions of the implants were measured for both anchor types and compared using Student's T-test for significance after calculating 95 % confidence intervals. RESULTS: In the transverse axis, the keel anchoring concept showed statistically significant (p < 0.05) lower mean values of micromotions compared to the spike anchoring concept. The highest micromotion values for both types were observed in the longitudinal axis. In no case the threshold of 200 micrometers was exceeded. CONCLUSIONS: Both fixation systems fulfill the required criteria of primary stability. Independent of the selected anchorage type an immediate postoperative active mobilization doesn't compromise the stability of the prostheses.

The Nottingham radiation protocol for O-arm navigation in paediatric deformity patients: a feasibility study.

BACKGROUND: O-arm assisted pedicle screw placement has been proven to be more accurate than free-hand technique. Radiation exposure remains the primary drawback. We determined the feasibility and safety of a reduced radiation protocol in paediatric patients undergoing scoliosis correction. METHODS: A reduced radiation protocol for a medtronic O-arm navigational system was devised. 3D CT reconstructions of an anthropomorphic pelvic phantom indicated adequate image quality after reduction to 14% of current manufacturer default factors. A feasibility study to test the image quality was undertaken on four patients, one with syndromic and three with idiopathic scoliosis each receiving progressively reducing radiation exposure of 60%, 50%, 40% and 14% of what would have been delivered using the manufacturer default protocol. This represented 32% of the mayo clinic protocol. It was achieved by reducing the x-ray tube current to 10 mA while keeping the tube potential at 90 kVp. RESULTS: A low dose O-arm protocol was able to generate adequate image quality while delivering as little as 14% (for lumbar region reconstructions) of the recommended protocol radiation dose. The total radiation dose delivered with this protocol was approximately 0.8 milliSieverts for a single spin. This effective dose represents < 1/3 of average UK and < 1/6 average US annual radiation exposure. There were no neurological or implant-related complications. CONCLUSIONS: Our low dose O-arm radiation protocol significantly reduces the radiation exposure compared to the manufacturer recommended Mayo clinic protocol providing operational image quality to allow accurate screw placement in spinal deformity.

Chest shielding in preterm neonates under phototherapy-a randomised control trial.

Shielding the precordium can effect manifestation of haemodynamically significant patent ductus arteriosus (hsPDA). Preterm neonates born at ≤ 32 weeks of gestation if needed phototherapy within 72 h of birth and had no echocardiographically proven hsPDA were eligible to be enrolled in this open-label randomised controlled trial. In chest shielding group, in addition to the standard care, left side of the chest was covered using food grade aluminium foil during phototherapy while control group received standard care. Mean gestational age (weeks; 30.1 ± 1.5 vs 30.1 ± 1.6) was comparable in the two groups. However, neonates in the chest shield group had lower birth weight (g; 1281 ± 259 vs 1422 ± 307) and were more likely to be small-for-gestational age (21.6% vs 8.0%). It was seen that 4 (7.8%) babies in the chest shield group and 5 (10%) babies in the standard group developed hsPDA after starting phototherapy with relative risk (RR) of 0.78 (95% CI 0.22-2.75). The left atrium to aortic ratio was significantly different in the two groups with 1.5 ± 0.1 in the chest shield group and 1.8 ± 0.2 in standard group (p value 0.03).Conclusion: Chest shielding of preterm babies during phototherapy has no effect on the incidence of haemodynamically significant patent ductus arteriosus.Trial registration: Trial was registered with Clinical trial registry of India (CTRI/2018/01/011069). What is Known: • Chest shielding in preterm neonates under phototherapy has inconclusive effect on the manifestation of patent ductus arteriosus. What is New: • Preterm neonates under phototherapy have no significant difference in manifestation of haemodynamically significant patent ductus arteriosus if precordium is shielded.

Procalcitonin -Vital Tool to Differentiate Septic Progression of Spondylodiscitis from Drug Hypersensitivity: A Case Report and Brief Review of Literature.

INTRODUCTION: Drug hypersensitivity is an important differential diagnosis in patients of infective spondylodiscitis, who develop systemic symptoms such as fever, rash, and arthralgia while on treatment with antibiotics. As these symptoms may also be present in sepsis progression, differentiation between two is very difficult. Procalcitonin (PCT) is one of the important and specific biomarkers of early sepsis. CASE REPORT: We present a case of a 33-year-old male with deep post-operative spinal infection complicated by drug hypersensitivity and worsening of systemic parameters. Serum PCT levels helped us to make correct diagnosis and prevent unnecessary surgical debridement. CONCLUSION: PCT, as a biomarker, can help distinguish the septic progression of spondylodiscitis from drug hypersensitivity and prove vital in clinical decision-making in these difficult scenarios.

Hypertrophic Obstructive Cardiomyopathy Requiring Ablation via Septals From Both Left and Right Coronary Arteries - A Case Report and Review of Literature.

Alcohol septal ablation has traditionally been performed using septal perforators from the left coronary system. We describe a case in which septal perforators from the left and right coronary arteries were utilized and review current literature on the management of hypertrophic obstructive cardiomyopathy.

Emergent TandemHeart-ECMO for acute severe mitral regurgitation with cardiogenic shock and hypoxaemia: a case series.

BACKGROUND: Acute severe mitral regurgitation (MR) associated with cardiogenic shock is a life-threatening emergency. Traditional teaching has focused on the need for emergent coronary angiography and/or intra-aortic balloon counterpulsation in preparation for emergent open-heart surgery for repair/replacement. Unfortunately, emergent open-heart surgery in patients with acute MR complicated by cardiogenic shock is associated with 25-46% perioperative mortality. New devices have provided additional options for stabilization prior to emergent surgery which facilitate improved outcomes. CASE SUMMARY: We present two cases of acute severe MR resulting in cardiogenic shock and profound hypoxaemia. TandemHeart® mechanical circulatory support with an oxygenator spliced into the circuit, akin to veno-arterial extracorporeal membrane oxygenation (ECMO), facilitated haemodynamic stabilization and decongestion of the lungs facilitating successful bridge to mitral valve surgery. Successful discharge to home was achieved in both patients with good neurological outcomes and sustained long-term functional recovery at 18 and 14 months, respectively. DISCUSSION: Selective use of the TandemHeart®, with or without ECMO, facilitates management of the critically ill cardiogenic shock patient with acute severe MR.

Peri-Implant Vertebral Body Fracture in a Cervical Integrated Cage Screw Construct: A Case Report of a Rare Complication.

CASE: A 33-year-old woman underwent C5-6 anterior cervical discectomy and fusion for progressive cervical myelopathy using an intergrated cage screw construct. Five weeks postoperatively, she presented with neck pain, worsening gait, and weakness after a slight jerk, with imaging showing peri-implant transverse fracture in the C6 vertebral body across the site of Caspar distractor pins and tips of the integrated cage screws. She was treated conservatively with hard collar with close observation, and at 6 months, she was asymptomatic with complete fracture union on imaging. CONCLUSION: Peri-implant fracture in a cervical integrated cage screw construct is a rare complication, with biomechanical implications to the pathogenesis, which shows good clinical outcome to conservative treatment.

Incidence, Risk Factors, and Outcome of Cardiac Arrhythmia Postcardiac Surgery in Children.

OBJECTIVE: To study the incidence of postoperative cardiac arrhythmias in children undergoing cardiac surgery and to evaluate the risk factors and outcome of these patients. MATERIALS AND METHODS: This retrospective observational study was conducted in the cardiac pediatric intensive care unit and included children <18 years of age. Children were monitored in the early postoperative period (72 h) for any sustained rhythm abnormality and were classified using standard definition. Details of treatment and their response were assessed. Risk factors for arrhythmias were evaluated using multivariate logistic regression analysis. RESULTS: Five hundred and thirty-six children were included and the prevalence of arrhythmia was 14.4% (n = 77). The most common arrhythmia was complete heart block (CHB) (n = 28; 5.2%), followed by junctional ectopic tachycardia (JET) (n = 25; 4.7%), junctional escape rhythm (n = 13; 2.4%), supraventricular tachycardia (SVT) (n = 8; 1.5%), and ventricular tachycardia (VT) (n = 3; 0.6%). Cardiac pacing was required in all CHB; 8 (28.6%) required a permanent pacemaker. Six (24%) patients with JET responded to conventional measures; 19 (76.0%) patients required amiodarone and 5 (20%) required cooling to 34°C or cardiac pacing. Temporary cardiac pacing was required in 9 (69.2%) cases of junctional escape rhythm. Seven (87.5%) events of SVT responded to adenosine and 1 (12.5%) required cardioversion. Two (66.7%) of VT responded to cardioversion while 1 (33.3%) was refractory. Five (6.5%) patients with arrhythmia died. In the multivariate logistic regression analysis, age <1 year, risk adjustment for congenital heart surgery category ≥3, and cross-clamp time >67 min were independent risk factors. CONCLUSION: Early postoperative period following cardiac surgery is extremely vulnerable to cardiac arrhythmias. Although majority are self-limiting, some can be life-threatening.

Bone marrow washout for multilevel vertebroplasty in multiple myeloma spinal involvement. Technical note.

INTRODUCTION: Vertebral involvement is found in a high percentage of multiple myeloma (MM) patients, often requiring multilevel surgical treatment to reduce pain and disability and to receive prompt access to oncological care. We describe the clinical use of washout technique for multilevel vertebroplasty in MM patients with diffuse spinal involvement. The aim of this technique is to reduce the risk of pulmonary fat embolism after cement injection and possibly to increment the amount of cement and treated levels in one surgical stage. METHODS: Three patients were treated with the washout technique prior to multilevel vertebroplasty for thoracolumbar diffuse spinal involvement in multiple myeloma. We describe the surgical technique and review the pertinent literature. RESULTS: The technique is clinically safe and effective in reducing pain, without significant complications. Two six-level vertebroplasties were performed in one case, allowing a larger amount of cement injected and a prompt start of the oncological treatment. CONCLUSIONS: Multilevel vertebroplasty in MM patients with diffuse spinal involvement carries the advantages of reducing pain, avoid repeated surgeries and faster return to oncological regimen. Cardiovascular complications, including pulmonary embolism, are rare but can have fatal consequences. It is mainly due to bone marrow mobilization during cement injection and the risk increases with the amount of cement injected and the number of treated levels. Despite multilevel treatment at the same stage, we did not observe any significant complication in our series. Further studies are needed to confirm the preliminary results of this technique. These slides can be retrieved under electronic supplementary material.

Stent augmentation of an anterior odontoid screw for type 2 odontoid fracture-dislocation in the elderly population: Report of two cases and literature review.

The fixation of type 2 odontoid fractures poses significant challenges in the elderly population due to coexistent osteoporosis and communition resulting in a high failure rate with conventional anterior screw fixation. Two elderly patients with unstable odontoid peg fractures and coexistent osteoporosis were treated with stentoplasty and anterior odontoid screw fixation. Additional anterior transarticular C1-2 screws were placed to address C1-2 instability. Both patients made an uneventful clinical recovery. One of the anterior C1-2 screws loosened due to the poor purchase in the osteoporotic bone in one patient. This did not affect the final outcome, and both the patients demonstrated maintained reduction and good alignment of odontoid peg after 2 years of follow-up. There was no intraoperative cement leak, pseudoarthrosis, or loss of reduction. Stentoplasty coupled with the anterior odontoid screw is a safe technique that can provide a biomechanically sound fixation of type 2 odontoid fractures in the presence of osteoporosis and significant communition.

Structural and Chemical Approach toward Understanding the Aqueous Corrosion of Sodium Aluminoborate Glasses.

Despite an ongoing strenuous effort to understand the compositional and structural drivers controlling the chemical durability of oxide glasses, there is still no complete consensus on the basic mechanism of glass dissolution that applies to a wide composition space. One major reason for this problem is the structural complexity contained within the multicomponent silicate glasses chosen for glass corrosion studies. The nonsilicate network polyhedra present in these glasses interact with one another, often in unpredictable ways, by forming a variety of structural associations, for example, Al[IV]-B[III] and B[III]-B[IV], resulting in significant influence on both the structure of the glass network and related macroscopic properties. Likewise, the formation of a variety of next-neighbor linkages, as well as increasingly complex interactions involving Si and differently coordinated next-nearest neighbor cations, is very difficult to decipher experimentally. Consideration of these factors motivates instead a different strategy: that is, the study of a sequence of SiO2-free ternary or quaternary glass compositions, whose structures can be unambiguously determined and robustly linked to their corrosion properties. With this aim, the present study is focused on understanding the structural drivers governing the kinetics and mechanism of corrosion of ternary Na2O-Al2O3-B2O3 glasses (in water) over a broad composition space comprising compositions with distinct structural features. It has been shown that the addition of Al2O3 to binary sodium borate glasses decreases their corrosion rate in water and converts their dissolution behavior from congruent to incongruent leading to the formation of six-coordinated alumina, and higher concentration of four-coordinated boron (in comparison to pre-dissolution glasses) in post-dissolution glass samples. The drivers controlling the corrosion kinetics and mechanism in these glasses based on their underlying structure have been elucidated. Some open questions have been proposed which require an extensive analysis of surface chemistry of pre- and post-dissolution samples and will be investigated in our future work.

Nano-phase separation and structural ordering in silica-rich mixed network former glasses.

We investigate the structure, phase separation, glass transition, and crystallization in a mixed network former glass series, i.e., B2O3-Al2O3-SiO2-P2O5 glasses with varying SiO2/B2O3 molar ratio. All the studied glasses exhibit two separate glassy phases: droplet phase (G1) with the size of 50-100 nm and matrix phase (G2), corresponding to a lower calorimetric glass transition temperature (Tg1) and a higher one (Tg2), respectively. Both Tg values decrease linearly with the substitution of B2O3 for SiO2, but the magnitude of the decrease is larger for Tg1. Based on nuclear magnetic resonance and Raman spectroscopy results, we infer that the G1 phase is rich in boroxol rings, while the G2 phase mainly involves the B-O-Si network. Both phases contain BPO4- and AlPO4-like units. Ordered domains occur in G2 upon isothermal and dynamic heating, driven by the structural heterogeneity in the as-prepared glasses. The structural ordering lowers the activation energy of crystal growth, thus promoting partial crystallization of G2. These findings are useful for understanding glass formation and phase separation in mixed network former oxide systems, and for tailoring their properties.

Giant thoracic discs: treatment, outcome, and follow-up of 33 patients in a single centre.

PURPOSE: To help guide treatment strategies and create insight into functional outcomes in patients with Giant herniated thoracic discs (GHTD), which are defined as occupying more than 40% of spinal canal. METHODS: Authors did a retrospective analysis of prospective cohort of 33 cases of GHTD, using clinical letters, notes, and telephonic questionnaires to determine their pre and postoperative functional status, surgical details, and complication rates. 16 males and 17 females operated between 2006 and 2014 were included in the study. A total of 23 patients underwent thoracotomy, 9 costotransversectomy, and 2 transpedicular approaches for excision of thoracic discs. Neuromonitoring was used in seven patients. RESULTS: Frankel grade improved by 1 in 13 patients and by 2 in 1 patient. One patient of T11/12 GHTD with neurogenic claudication recovered completely, taking the overall improvement rate to 45.5%. It remained static in 15 patients (45.5%) and deteriorated by 1 in 3 patients (9%). By mJOA scoring too, the outcome was favorable in majority (84.4%) of patients. There were three intraoperative complications (9%), which included two incidental durotomies and one massive blood loss. Late postoperative complications were seen in 12(39%) patients. They included intercostal neuralgia, mechanical pain around costotransversectomy, progressive thoracic paraplegia due to spinal cord herniation and residual disc fragments, reactive pleural effusion, CSF fistula induced pleural effusion, and infective discitis. CONCLUSIONS: Surgery for giant herniated thoracic disc has favorable outcome in majority (91%) of patients. However, significant approach-related complications are to be anticipated in patients undergoing thoracotomies, most of them being manageable. Author recommends costotransversectomy, only in paracentral discs with smaller percentage canal stenosis.

The in vivo performance of an alkali-free bioactive glass for bone grafting, FastOs® BG, assessed with an ovine model.

Although bioactive glasses are successfully used as bone substitutes, recent studies have revealed that the high alkali content in these glasses leads to fast in vivo degradation rates that may not match the rate of new bone ingrowth. This prompted us to design and develop novel bioactive glasses that are devoid of alkali but still demonstrate high bioactivity in vitro. This article describes the in vivo performance of an alkali-free bioactive glass with the following composition (Wt %): 13.03 MgO-33.98 CaO-13.37 P2 O5 -38.84 SiO2 -0.77 CaF2 (labelled as FastOs® BG). An animal model was used to assess the in vivo performance of FastOs® BG, using 45S5 Bioglass® as control. The evaluation was performed through implantation of FastOs® BG and 45S5 Bioglass® , during one month, in femoral bone defects in sheep. Subcutaneous implantation of both glasses was also performed in order to assess tissue response through a standardized method. Histological and scanning electron microscopy assessment of retrieved subcutaneous and bone samples demonstrated that FastOs® BG is biocompatible, osteoconductive, that it can be osteointegrated, and that it is more slowly resorbed than 45S5 Bioglass® . These features suggest that FastOs® BG is a potential candidate for bone grafting. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 30-38, 2017.

Influence of ZnO/MgO substitution on sintering, crystallisation, and bio-activity of alkali-free glass-ceramics.

The present study reports on the influence of partial replacement of MgO by ZnO on the structure, crystallisation behaviour and bioactivity of alkali-free bioactive glass-ceramics (GCs). A series of glass compositions (mol%): 36.07 CaO-(19.24-x) MgO-x ZnO-5.61 P2O5-38.49 SiO2-0.59 CaF2 (x=2-10) have been synthesised by melt-quench technique. The structural changes were investigated by solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR), X-ray diffraction and differential thermal analysis. The sintering and crystallisation behaviours of glass powders were studied by hot-stage microscopy and differential thermal analysis, respectively. All the glass compositions exhibited good densification ability resulting in well sintered and mechanically strong GCs. The crystallisation and mechanical behaviour were studied under non-isothermal heating conditions at 850 °C for 1h. Diopside was the primary crystalline phase in all the GCs followed by fluorapatite and rankinite as secondary phases. Another phase named petedunnite was identified in GCs with ZnO content >4 mol. The proliferation of mesenchymal stem cells (MSCs) and their alkaline phosphatase activity (ALP) on GCs was revealed to be Zn-dose dependent with the highest performance being observed for 4 mol% ZnO.

Understanding the composition-structure-bioactivity relationships in diopside (CaO·MgO·2SiO2)-tricalcium phosphate (3CaO·P2O5) glass system.

The present work is an amalgamation of computation and experimental approach to gain an insight into composition-structure-bioactivity relationships of alkali-free bioactive glasses in the CaO-MgO-SiO2-P2O5 system. The glasses have been designed in the diopside (CaO·MgO·2SiO2; Di)-tricalcium phosphate (3CaO·P2O5; TCP) binary join by varying the Di/TCP ratio. The melt-quenched glasses have been investigated for their structure by molecular dynamic (MD) simulations as well as by nuclear magnetic resonance spectroscopy (NMR). In all the investigated glasses silicate and phosphate components are dominated by Q(2) (Si) and Q(0) (P) species, respectively. The apatite forming ability of the glasses was investigated using X-ray diffraction (XRD), infrared spectroscopy after immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the investigated glasses showed good bioactivity without any substantial variation. A significant statistical increase in metabolic activity of human mesenchymal stem cells (hMSCs) when compared to the control was observed for Di-60 and Di-70 glass compositions under both basal and osteogenic conditions.

Navigated pedicle screw placement using computed tomographic data in dorsolumbar fractures.

BACKGROUND: Computed tomographic (CT) based navigation is a technique to improve the accuracy of pedicle screw placement. It is believed to enhance accuracy of pedicle screw placement, potentially avoiding complications arising due to pedicle wall breach. This study aims to assess the results of dorsolumbar fractures operated by this technique. MATERIALS AND METHODS: Thirty consecutive skeletally mature patients of fractures of dorsolumbar spine (T9-L5) were subjected to an optoelectronic navigation system. All patients were thoroughly examined for neurological deficit. The criterion for instability were either a tricolumnar injury or presence of neurological deficit or both. Patients with multilevel fractures and distorted spine were excluded from study. Time taken for insertion of each pedicle screw was recorded and placement assessed with a postoperative CT scan using Laine's grading system. RESULTS: Only one screw out of a total of 118 screws was misplaced with a Laine's Grade 5 placement, showing a misplacement rate of 0.847%. Average time for matching was 7.8 min (range 5-12 min). Average time taken for insertion of a single screw was 4.19 min (range 2-8 min) and total time for all screws after exposure was 34.23 min (range 24-45 min) for a four screw construct. No neurovascular complications were seen in any of the patients postoperatively and in subsequent followup of 1-year duration. CONCLUSION: CT-based navigation is effective in improving accuracy of pedicle screw placement in traumatic injuries of dorsolumbar spine (T9-L5), however additional cost of procuring CT scan to the patient and cost of equipment is of significant concern in developing countries. Reduced radiation exposure and lowered ergonomic constraints around the operation table are its additional benefits.

Role of glass structure in defining the chemical dissolution behavior, bioactivity and antioxidant properties of zinc and strontium co-doped alkali-free phosphosilicate glasses.

We investigated the structure-property relationships in a series of alkali-free phosphosilicate glass compositions co-doped with Zn(2+) and Sr(2+). The emphasis was laid on understanding the structural role of Sr(2+) and Zn(2+) co-doping on the chemical dissolution behavior of glasses and its impact on their in vitro bioactivity. The structure of glasses was studied using molecular dynamics simulations in combination with solid state nuclear magnetic resonance spectroscopy. The relevant structural properties are then linked to the observed degradation behavior, in vitro bioactivity, osteoblast proliferation and oxidative stress levels. The apatite-forming ability of glasses has been investigated by X-ray diffraction, infrared spectroscopy and scanning electron microscopy-energy-dispersive spectroscopy after immersion of glass powders/bulk in simulated body fluid (SBF) for time durations varying between 1h and 14 days, while their chemical degradation has been studied in Tris-HCl in accordance with ISO 10993-14. All the glasses exhibit hydroxyapatite formation on their surface within 1-3h of their immersion in SBF. The cellular responses were observed in vitro on bulk glass samples using human osteosarcoma MG63 cell line. The dose-dependent cytoprotective effect of glasses with respect to the concentration of zinc and strontium released from the glasses is also discussed.