Unexpected positive cultures in presumed aseptic revision spine surgery using sonication.

AIMS: During revision procedures for aseptic reasons, there remains a suspicion that failure may have been the result of an undetected subclinical infection. However, there is little evidence available in the literature about unexpected positive results in presumed aseptic revision spine surgery. The aims of our study were to estimate the prevalence of unexpected positive culture using sonication and to evaluate clinical characteristics of these patients. PATIENTS AND METHODS: All patients who underwent a revision surgery after instrumented spinal surgery at our institution between July 2014 and August 2016 with spinal implants submitted for sonication were retrospectively analyzed. Only revisions presumed as aseptic are included in the study. During the study period, 204 spinal revisions were performed for diagnoses other than infection. In 38 cases, sonication cultures were not obtained, leaving a study cohort of 166 cases. The mean age of the cohort was 61.5 years (sd 20.4) and there were 104 female patients. RESULTS: Sonication cultures were positive in 75 cases (45.2%). Hardware failure was the most common indication for revision surgery and revealed a positive sonication culture in 26/75 cases (35%) followed by adjacent segment disease (ASD) in 23/75 cases (30%). Cutibacterium acnes and Staphylococcus epidermidis were the most commonly isolated microorganisms, observed in 45% and 31% of cases, respectively. C. acnes was isolated in 65.2% of cases when the indication for revision surgery was ASD. CONCLUSION: Infection must always be considered as a possibility in the setting of spinal revision surgery, especially in the case of hardware failure, regardless of the lack of clinical signs. Sonication should be routinely used to isolate microorganisms adherent to implants. Cite this article: Bone Joint J 2019;101-B:621-624.

Long-Term Effects of Intravenous Iloprost Therapy in Patients with Bone Marrow Oedema of the Knee Joint.

PURPOSE OF THE STUDY Bone marrow oedema (BMO) syndrome is a multifactorial condition. Various conservative treatment options include analgesic therapy, immobilisation of the affected joint and/or systemic intravenous iloprost therapy. Many studies have confirmed the positive effect of iloprost therapy, but only after short-term follow-up. The purpose of this study was to show that treatment with iloprost leads to positive long-term functional and radiological outcomes for BMO of the knee. MATERIAL AND METHODS Fifteen patients with BMO of the knee joint, ARCO stage 1-2, were included in this study. Various questionnaires, the Lysholm Score, the SF-36, WOMAC, Knee Society Score, and a visual analogue pain scale (VAS), were evaluated before and after iloprost therapy. All patients underwent MRI for radiological follow-up three months after treatment. RESULTS Significant improvements were found in the Lysholm Score, SF-36, WOMAC and KSS. In 80% of patients, follow-up MRI after three months showed complete regression of the oedema. Three patients received additional surgery after a follow-up period of 33 ± 7 months. CONCLUSIONS Based on the positive results of our study, we recommend treatment with iloprost for BMO of the knee in ARCO stage 1-2 patients. Key words:iloprost, bone marrow oedema, knee joint.

Calcaneal Displacement Osteotomies - Less Soft Tissue Irritation in Lateral Compression Plate than Screws.

PURPOSE OF THE STUDY With the concept of the lateral compression plate (LLCP) a technique has been available designed to combine the advantages of a fixed-angle fixation with a complete sinking of the implant into the proximal bone. The objective of the present study was to investigate the results of the LLCP compared with classical screw osteosynthesis (SO). MATERIAL AND METHODS 31 patients with pes planovalgus who received calcaneal displacement osteotomy and osteosyntheses with screws (n = 17) or LLCP (n = 14) between 2010 and 2015 were investigated retrospectively.The ankle-hindfoot scale, Kaikkonen score, VAS, and the SF-36 were determined preoperatively as well as at the last clinical follow-up. In addition, a radiological control of osseous integration was performed in all patients 12 weeks after surgery. RESULTS With regard to clinical scores both methods depicted significant improvement. In the overall cohort there were no pseudarthroses. In the SO group 5 cases (29%) showed hardware irritation, in the LLCP group there were none. Results in the LLCP group were significantly superior in the area of the physical section of the SF 36. CONCLUSIONS Based on the results of our study, surgical treatment of stage II pes planovalgus by means of calcaneal displacement osteotomy using the LLCP is equivalent to SO with a lower incidence of hardware irritation. Key words:pes planovalgus, lateral compression plate, osteosynthesis, screw, hardware irritation. LEVEL OF EVIDENCE: Level IV, retrospective case serie.

Establishing an Interdisciplinary Compulsory Elective Subject 'Spine' in the Curriculum of the University Study Course of Human Medicine.

PURPOSE OF THE STUDY Back pain and pathologies of the spine are among the main reasons why people consult a doctor, both general practitioners and paediatricians, as well as, specifically, orthopaedists, surgeons, and neurosurgeons. This involvement of different faculties calls for a high degree of interdisciplinary co-operation. In order to mediate these aspects of spine-specific diagnostics, therapy, and research to students during their studies and to promote up-and-coming specialists, the compulsory elective subject 'Spine' was established. MATERIAL AND METHODS From the winter semester of 2013 to the winter semester of 2014, the compulsory elective subject 'Spine' was offered to interested students in the 7th semester of their studies of human medicine. The maximum number of participants per course was 16. Each course lasted four weeks. The subjects taught covered the fields of degeneration, deformities, and destruction in the specialist disciplines of orthopaedics, traumatology, neurosurgery, and rehabilitation medicine. In addition, orthopaedic technology and the local musculoskeletal and biomechanical research institute were integrated into the course. Various teaching methods were applied, including problem oriented learning, seminars, observation or consultation, and internship. At the end, the course was evaluated with regard to subjective learning success, knowledge gain, satisfaction, and interdisciplinarity. Participants were compared with all students of the semester employing an objectively structured clinical examination (OSCE). RESULTS Forty-eight students took part in the compulsory elective subject 'Spine'. The compulsory elective subject was given a positive rating in all fields. In the learning success control, all of the students had good to very good results. Students attending the elective subject performed significantly better in the objective structured clinical examination (OSCE) (p ≤ 0.001). The compulsory elective course continues to be offered in the curriculum with a slightly altered schedule. CONCLUSIONS In view of the high prevalence of patients with back pain and its associated importance in terms of healthcare policy and social relevance, our experience leads us to recommend the general integration of such a compulsory elective subject in the study of human medicine. Key words:elective subject, spine, students, spinal disorders.

[Characteristics of neuromuscular scoliosis]. / Besonderheiten neuromuskulärer Skoliosen.

Usually, neuromuscular scolioses become clinically symptomatic relatively early and are rapidly progressive even after the end of growth. Without sufficient treatment they lead to a severe reduction of quality of life, to a loss of the ability of walking, standing or sitting as well as to an impairment of the cardiopulmonary system resulting in an increased mortality. Therefore, an intensive interdisciplinary treatment by physio- and ergotherapists, internists, pediatricians, orthotists, and orthopedists is indispensable. In contrast to idiopathic scoliosis the treatment of patients with neuromuscular scoliosis with orthosis is controversially discussed, whereas physiotherapy is established and essential to prevent contractures and to maintain the residual sensorimotor function.Frequently, the surgical treatment of the scoliosis is indicated. It should be noted that only long-segment posterior correction and fusion of the whole deformity leads to a significant improvement of the quality of life as well as to a prevention of a progression of the scoliosis and the development of junctional problems. The surgical intervention is usually performed before the end of growth. A prolonged delay of surgical intervention does not result in an increased height but only in a deformity progression and is therefore not justifiable. In early onset neuromuscular scolioses guided-growth implants are used to guarantee the adequat development. Because of the high complication rates, further optimization of these implant systems with regard to efficiency and safety have to be addressed in future research.

In serum veritas-in serum sanitas? Cell non-autonomous aging compromises differentiation and survival of mesenchymal stromal cells via the oxidative stress pathway.

Even tissues capable of complete regeneration, such as bone, show an age-related reduction in their healing capacity. Here, we hypothesized that this decline is primarily due to cell non-autonomous (extrinsic) aging mediated by the systemic environment. We demonstrate that culture of mesenchymal stromal cells (MSCs) in serum from aged Sprague-Dawley rats negatively affects their survival and differentiation ability. Proteome analysis and further cellular investigations strongly suggest that serum from aged animals not only changes expression of proteins related to mitochondria, unfolded protein binding or involved in stress responses, it also significantly enhances intracellular reactive oxygen species production and leads to the accumulation of oxidatively damaged proteins. Conversely, reduction of oxidative stress levels in vitro markedly improved MSC function. These results were validated in an in vivo model of compromised bone healing, which demonstrated significant increase regeneration in aged animals following oral antioxidant administration. These observations indicate the high impact of extrinsic aging on cellular functions and the process of endogenous (bone) regeneration. Thus, addressing the cell environment by, for example, systemic antioxidant treatment is a promising approach to enhance tissue regeneration and to regain cellular function especially in elderly patients.

Monitoring the load on a telemeterised vertebral body replacement for a period of up to 65 months.

PURPOSE: To determine the postoperative temporal course of the forces acting on a vertebral body replacement (VBR) for two well reproducible activities. METHODS: A telemeterised VBR was implanted in five patients. It allows the measurement of six load components. Implant loads were measured in up to 28 measuring sessions for different activities, including standing and walking. RESULTS: The postoperative temporal course of the resultant implant forces measured during standing and walking was similar in each patient, but the patterns varied strongly from patient to patient. In one patient, the forces decreased in the first year and then increased in the following 4 years. In another patient, the forces increased in the first few months and then decreased. In a third patient, the forces varied only slightly in the postoperative time. In two patients, there was a strong drop of the implant force in the first two postoperative months. The force was on average approximately 100 N or 71% higher for walking than for standing. CONCLUSIONS: The strong force reduction in the first 2 months is most likely caused by implant subsidence, and the force reduction over a period of more than 6 months is most likely caused by fusion of the vertebrae adjacent to the VBR. The short-term force increase could be attributed to bone atrophy at the index level, and the long-term force increase could be attributed to an increase in the thoracic spine kyphosis angle.

Parameters influencing the outcome after total disc replacement at the lumbosacral junction. Part 1: misalignment of the vertebrae adjacent to a total disc replacement affects the facet joint and facet capsule forces in a probabilistic finite element analysis.

PURPOSE: After total disc replacement with a ball-and-socket joint, reduced range of motion and progression of facet joint degeneration at the index level have been described. The aim of the study was to test the hypothesis that misalignment of the vertebrae adjacent to the implant reduces range of motion and increases facet joint or capsule tensile forces. METHODS: A probabilistic finite element analysis was performed using a lumbosacral spine model with an artificial disc at level L5/S1. Misalignment of the L5 vertebra, the gap size of the facet joints, the transection of the posterior longitudinal ligament, and the spinal shape were varied. The model was loaded with pure moments. RESULTS: Misalignment of the L5 vertebra reduced the range of motion up to 2°. A 2-mm displacement of the L5 vertebra in the anterior direction already led to facet joint forces of approximately 240 N. Extension, lateral bending, and axial rotation caused maximum facet joint forces between 280 and 380 N, while flexion caused maximum forces of approximately 200 N. A 2-mm displacement in the posterior direction led to capsule forces of approximately 80 N. Additional moments increased the maximum facet capsule forces to values between 120 and 230 N. CONCLUSIONS: Misalignment of the vertebrae adjacent to an artificial disc strongly increases facet joint or capsule forces. It might, therefore, be an important reason for unsatisfactory clinical results. In an associated clinical study (Part 2), these findings are validated.

MR-guided discography using an open 1 Tesla MRI system.

OBJECTIVE: To evaluate the feasibility of MR-guided discography using an open 1 Tesla MRI system. METHODS: 48 disc segments of 41 patients scheduled for intradiscal thermal treatment, total disc replacement or spondylodesis were examined. A 1.0-T open MRI was used for instrument guidance and imaging. After primary disc puncture under guidance of interactive PDw TSE imaging, 1-2 ml of gadolinium contrast saline mixture was injected into the disc. The occurrence of memory pain during injection was recorded. Axial and sagittal T1w TSE images with and without fat saturation were obtained. All MRI discograms were analysed by two readers, who were blinded to the clinical findings. RESULTS: Overall, the placement of the puncture needle in the targeted disc was accurate under real-time MR guidance. Injections were technically successful in all cases. No major complications occurred. The mean procedure time was 17 min (range 13-34 min). Image quality of contrast-enhanced MR discograms was excellent when using an optimized gadolinium contrast saline mixture of 1:600. Memory pain was detected in 16 out of 48 affected segments. CONCLUSION: MR-guided discography is accurate and safe. Multiplanar dynamic imaging facilitates the puncture of discs and provides high-quality MR discograms.

[Monosegmental anterior lumbar interbody fusion with the SynFix-LR™ device. A prospective 2-year follow-up study]. / Die monosegmentale ventrale Spondylodese mit dem SynFix-LR™. Eine prospektive 2-Jahres-Studie.

BACKGROUND: With anterior lumbar interbody fusion (ALIF) alone, the morbidity associated with a posterior approach can be avoided. In this study we evaluated the use of a PEEK cage with an integrated angle-stable locking plate (SynFix-LR™). MATERIAL AND METHODS: Thirty-two patients with osteochondrosis at L4/5 or L5/S1 were treated with the SynFix-LR™. Follow-up at 0, 3, 6, 9, 12, and 24 months included the Oswestry Disability Index (ODI), visual analog scale (VAS), and questions regarding satisfaction and use of pain medication. The fusion rate was assessed by X-ray and computed tomography (CT) examination. RESULTS: A significant reduction of the ODI and VAS was achieved (p<0.05) with a high rate of patient satisfaction. After 2 years, 79% of the patients were able to dispense with long-term use of analgesics. We observed a fusion rate of 93% (X-ray) and 70% (CT) at final follow-up. CONCLUSION: The SynFix-LR™ device is a suitable option for the treatment of monosegmental osteochondrosis at L4/5 and L5/S1 with comparable or superior results in comparison to posterior or combined fusion techniques.

Influences of age and mechanical stability on volume, microstructure, and mineralization of the fracture callus during bone healing: is osteoclast activity the key to age-related impaired healing?

Earlier studies have shown that the influence of fixation stability on bone healing diminishes with advanced age. The goal of this study was to unravel the relationship between mechanical stimulus and age on callus competence at a tissue level. Using 3D in vitro micro-computed tomography derived metrics, 2D in vivo radiography, and histology, we investigated the influences of age and varying fixation stability on callus size, geometry, microstructure, composition, remodeling, and vascularity. Compared were four groups with a 1.5-mm osteotomy gap in the femora of Sprague-Dawley rats: Young rigid (YR), Young semirigid (YSR), Old rigid (OR), Old semirigid (OSR). Hypothesis was that calcified callus microstructure and composition is impaired due to the influence of advanced age, and these individuals would show a reduced response to fixation stabilities. Semirigid fixations resulted in a larger DeltaCSA (Callus cross-sectional area) compared to rigid groups. In vitro microCT analysis at 6 weeks postmortem showed callus bridging scores in younger animals to be superior than their older counterparts (p<0.01). Younger animals showed (i) larger callus strut thickness (p<0.001), (ii) lower perforation in struts (p<0.01), and (iii) higher mineralization of callus struts (p<0.001). Callus mineralization was reduced in young animals with semirigid fracture fixation but remained unaffected in the aged group. While stability had an influence, age showed none on callus size and geometry of callus. With no differences observed in relative osteoid areas in the callus ROI, old as well as semirigid fixated animals showed a higher osteoclast count (p<0.05). Blood vessel density was reduced in animals with semirigid fixation (p<0.05). In conclusion, in vivo monitoring indicated delayed callus maturation in aged individuals. Callus bridging and callus competence (microstructure and mineralization) were impaired in individuals with an advanced age. This matched with increased bone resorption due to higher osteoclast numbers. Varying fixator configurations in older individuals did not alter the dominant effect of advanced age on callus tissue mineralization, unlike in their younger counterparts. Age-associated influences appeared independent from stability. This study illustrates the dominating role of osteoclastic activity in age-related impaired healing, while demonstrating the optimization of fixation parameters such as stiffness appeared to be less effective in influencing healing in aged individuals.

[Histopathological diagnosis of periprosthetic joint infection following total hip arthroplasty : use of a standardized classification system of the periprosthetic interface membrane]. / Histopathologische Diagnose der periprothetischen Gelenkinfektion nach Hüftgelenkersatz : Verwendung eines standardisierten Klassifikationssystems der periprothetischen Interface-Membranen.

BACKGROUND: The distinction between aseptic and septic loosening of a total hip arthroplasty is a diagnostic challenge. Therapy and clinical success depend on the correct diagnosis. Histopathological evaluation of the periprosthetic interface membrane is one possible diagnostic parameter; detailed analysis of tissue characteristics may reflect the cause of failure. This study evaluated the diagnostic value of a published histopathological consensus classification for the periprosthetic interface membrane in the identification of periprosthetic joint infection (PJI). METHODS: Between 2004 and 2008, a prospective analysis was performed in 106 patients who had revisions because of assumed PJI. Based on clinical presentation, radiography, and haematological screening, infection was assumed, and a joint aspiration was performed. Based on these findings, a two-stage revision was performed, with intraoperative samples for culture and histological evaluation obtained. Final diagnosis of infection was based on the interpretation of the clinical presentation and the preoperative and intraoperative findings. The basis for histopathological evaluation was the consensus classification for the periprosthetic interface membrane. Sensitivity, specificity, and accuracy were calculated for each parameter. RESULTS: In 92 patients, a positive diagnosis of PJI could be made. Histopathology yielded the highest accuracy (0.93) in identification of PJI, identifying 86 of 92 infections (69 type II, 17 type III). In 13 of the 14 noninfected hips, histopathology correlated in 13 (93%) cases (10 type I, three type IV). The accuracies of microbiological culture, C-reactive protein, and aspiration were 0.82, 0.86, and 0.54, respectively. CONCLUSION: In the diagnosis of PJI, histopathological evaluation of the periprosthetic interface membrane proved very effective. To analyse the cause of prosthesis loosening, tissue samples of the periprosthetic interface membrane should be evaluated on the basis of the consensus classification in all revision surgeries.

Randomized crossover comparison of the proseal with the classic laryngeal mask airway in unparalysed anaesthetized patients.

BACKGROUND: The ProSeal is a wire-reinforced laryngeal mask airway with an additional drain tube that leads to the distal tip of the laryngeal cuff. The design should improve the seal with the larynx. METHODS: The ProSeal and classic laryngeal mask airways were compared in 180 patients in a randomized crossover study. Patients were anaesthetized without neuromuscular blocking drugs. RESULTS: The ProSeal took more time and more attempts to insert successfully than the classic laryngeal mask airway. Insertion was successful on the first attempt in 81% of cases with the ProSeal and 90% with the classic laryngeal mask airway. The ProSeal required more air to achieve an intracuff pressure of 60 cm H2O (6 ml more for size 4 and 12 ml more for size 5). Laryngeal seal pressure was better with the ProSeal than the classic laryngeal mask airway. Median seal pressure was 29 cm H2O with the ProSeal and 18 cm H2O with the classic laryngeal mask airway. Laryngeal seal pressure was greater than 20 cm H2O in 87% of patients with the ProSeal and 41% with the classic laryngeal mask airway. Laryngeal seal pressure was greater than 40 cm H2O in 21% of patients with the ProSeal and in none of the patients with the classic laryngeal mask. Once placed, the ProSeal remained a stable and effective airway. Gastric tube insertion through the drain tube was attempted in 147 cases and was successful in 135 (92%). CONCLUSION: The ProSeal is more difficult to insert than the classic laryngeal mask airway but allows positive pressure ventilation more reliably than the classic laryngeal mask airway.

The LMA 'ProSeal'--a laryngeal mask with an oesophageal vent.

We describe a new laryngeal mask airway (LMA) that incorporates a second tube placed lateral to the airway tube and ending at the tip of the mask. The second tube is intended to separate the alimentary and respiratory tracts. It should permit access to or escape of fluids from the stomach and reduce the risks of gastric insufflation and pulmonary aspiration. It can also determine the correct positioning of the mask. A second posterior cuff is fitted to improve the seal. A preliminary crossover comparison with the standard mask in 30 adult female patients showed no differences in insertion, trauma or quality of airway. At 60 cm H2O intracuff pressure, the new LMA gave twice the seal pressure of the standard device (P < 0.0001) and permitted blind insertion of a gastric tube in all cases. It is concluded that the new device merits further study.

A new laryngeal mask prototype. Preliminary evaluation of seal pressures and glottic isolation.

A new prototype laryngeal mask airway is described which incorporates a second mask to isolate the upper oesophagus and a second dorsal cuff to increase the seal against the glottis. We have made a within-patient comparison of seal pressures between the prototype and standard laryngeal mask airway in 20 patients, and determined if the prototype facilitates functional isolation of the glottis and upper oesophagus. Leak pressure was found to be significantly higher for the prototype and equalled or exceeded 5.0 kPa in all patients (p < 0.001). The prototype laryngeal mask airway provided functional isolation in all patients as judged by leak and placement of a gastric tube via the oesophageal mask. Ease of insertion and incidence of pharyngeal morbidity appeared similar to the standard laryngeal mask, but were not formally tested. The prototype laryngeal mask airway exhibits potentially useful new features which justify further evaluation and development.

Challenging contrasts: scientists and nurses.

Quality teaching requires insights into learners' perceptions of the subject matter and those professionals who use it. Practitioners can benefit from knowledge of how they are perceived generally in society, which provides insight into their own performance. In a paper related to this one, the authors generated data about science and scientists from 229 short stories about science by Australian secondary students. The findings were similar to other image research about scientists and science. The authors then surveyed literature about the image of nurses and nursing. This revealed strongly contrasting images for science/scientists and nurse/nursing. This paper documents the contrasts and explores the implications for science educators working in Schools of Nursing.

Serum fluoride levels in morbidly obese patients: enflurane compared with isoflurane anaesthesia.

Obese patients are known to metabolise anaesthetic agents more than patients of normal weight. The extent of this was investigated by the measurement of serum fluoride concentrations in 10 morbidly obese patients undergoing gastroplasty. Five were allocated to receive enflurane and five to receive isoflurane supplemented anaesthesia. The mean peak serum fluoride concentrations after enflurane anaesthesia were greater (22.7 mumol/litre, SE 2.9) than after isoflurane anaesthesia (6.5 mumol/litre, SE 0.6). The mechanisms and implications of this finding are discussed.

Ketamine by continuous infusion in status asthmaticus.

A 13-year-old girl was admitted to the intensive care unit with status asthmaticus. Conventional bronchodilator therapy failed to relieve her bronchospasm. In order to try and avoid artificial ventilation, a continuous intravenous infusion of ketamine was used with success. The total dose rate was 40 micrograms/kg minute for a period of 8 hours; this was given at a decreasing rate. She regained consciousness 30 minutes after the end of the infusion and became well orientated after one hour. Ketamine is a useful drug in the intensive treatment of status asthmaticus and should be tried before a decision is taken to start mechanical ventilation.