Randomized Controlled Trial of Posterior Lumbar Interbody Fusion With Ti- and CaP-Nanocoated Polyetheretherketone Cages: Comparative Study of the 1-Year Radiological and Clinical Outcome.

BACKGROUND: Polyetheretherketone (PEEK) is a popular material for posterior lumbar interbody fusion (PLIF) cages, although osseointegration remains limited. To optimize PEEK cage characteristics, titanium (Ti) and calcium phosphate (CaP) nanocoatings have been developed with proven mechanical safety. This multicenter randomized controlled trial compared the clinical and radiological outcome parameters of nanocoated and uncoated PEEK cages, up to 1 year after surgery. METHODS: Standard open PLIF surgery was performed on 127 patients, randomized in 3 groups: Ti-nanocoated (n = 44), CaP-nanocoated (n = 46), and uncoated PEEK cages (n = 37). Clinical assessments up to 1 year after surgery included visual analogue scales (VASs), Oswestry Disability Index (ODI), and 36-Item Short Form Survey (SF-36). Primary radiological outcome parameters were implant stability and fusion status, assessed by x-ray and computed tomography (CT) scans. Patients, surgeons, and postsurgery analysts were blinded. RESULTS: PLIF surgery with all cage types resulted in significant improvements of clinical outcome parameters, exceeding the minimum clinically important differences. No significant differences in VAS, ODI, or SF-36 scores were found among the 3 groups. One year after the surgery, 65.6% of patients with uncoated PEEK cages achieved definite fusion. Significantly more patients with nanocoated PEEK cages achieved definite fusion: 93.9% for Ti nanocoating (P = .0034) and 88.0% for CaP nanocoating (P = .032). No significant differences in fusion were found between the nanocoated cage types (P = .4318). CONCLUSIONS: The similar clinical outcome improvements after 1 year suggest that nanocoated PEEK cages have the same safety and efficacy as the clinically accepted uncoated PEEK cages. Furthermore, nanocoated PEEK cages achieved a better fusion rate than uncoated PEEK cages at the 1-year follow-up. A 5-year follow-up study is warranted to revisit the findings. CLINICAL RELEVANCE: The safety, efficacy, and enhanced osseointegration of nanocoated PEEK cages were demonstrated. Osseointegration is a significant predictor of positive long-term clinical outcomes and improved implant longevity, implying a clinical added value of nanocoatings. Enhanced osseointegration becomes even more important in minimally invasive spine surgery and in patients at risk for incomplete fusion.

ISQ calculation evaluation of in vitro laser scanning vibrometry-captured resonance frequency.

BACKGROUND: Implant stability testing at various stages of implant therapy by means of resonance frequency analysis is extensively used. The overall measurement outcome is a function of the resulting stiffness of three entities: surrounding bone, bone-implant complex, and implant-Smartpeg complex. The influence of the latter on the overall measurement results is presently unknown. It can be investigated in vitro by use of imbedded implants with mounted Smartpegs. This enables to keep the influence of the two other entities constant and controlled. The purpose of this study is to verify if a laboratory laser Doppler vibrometry technology-based procedure results in comparable ISQ results after calculation of captured resonance frequency spectra by aid of the Osstell algorithm with direct Osstell IDX device measurements. METHODS: A laboratory procedure was engineered to record frequency spectra of resin-imbedded test implants with mounted Smartpegs, after electromagnetic excitation with the Osstell IDX device and laser Doppler vibrometry response detection. Fast Fourier transformation data processing of resonance frequency data resulted in determination of a maximum resonance frequency values allowing calculation of implant stability quotient (ISQ) values using the Osstell algorithm. RESULTS: Laboratory-based ISQ values were compared to Osstell IDx device-generated ISQ values for Straumann tissue level, Ankylos, and 3i Certain implant systems. For both systems, a correlation coefficient r = 0.99 was found. Furthermore, a clinically rejectable mean difference of 0.09 ISQ units was noted between both datasets. CONCLUSIONS: The proposed laboratory method with the application of the Osstell algorithm for ISQ calculation is appropriate for future studies to in vitro research aspects of resonance frequency analysis implant stability measurements.

Updated secondary implant stability data of two dental implant systems. A retrospective cohort study.

BACKGROUND: At present, updated secondary implant stability data generated by actual versions of resonance frequency analysis (RFA) and mobility measurement (MM) electronic devices of 2 different implant systems with actual manufactured surfaces seem to lack and/or are incomplete. MATERIAL AND METHODS: Secondary implant stability data based on both RFA and MM measurements were collected and analyzed from 44 formerly treated patients (24 f, 20 m) that received either Ankylos Cellplus (Ø3.5mm) (A) (n=36) or Straumann regular neck SLA tissue level (Ø4.1mm) (S) (n=37) implants in posterior positions of both jawbones (total number= 72). These results were interpretated in view of formerly published data. RESULTS: Estimated RFA outcomes (mean±SD) for A implants were of 81.23 (±0.65) (LP) - 76.15 (±1.57) (UP) isq; for S implants 76.15 (±1.48) (LP) - 73.88 (±2.34) (UP) isq. Estimated MM outcomes for A implants were (-4.0) (±0.23) (LP) - (-3.2) (±0.33) (UP) ptv; for S implants (-5.15) (±0.39) (LP) - (-4.4) (±0.84) (UP) ptv. According to GEE statistical modelling, implant type and - position seems to influence the outcome variables (p<0.05), gender and implant length did not (p >0.05). CONCLUSIONS: Secondary implant stability values, recorded with current RFA and MM devices, of A Cellplus implants are provided for the first time. A difference of 14.7-9.7 isq values was noted for CellPlus versus TPS S implants recorded with a cabled RFA device. This study supports the assumption that RFA outcomes generated with first generation RFA devices are different from those obtained with current RFA devices, meaning that its use in reviews need caution and correction. Key words:Secondary implant stability, resonance frequency analysis, Periotest, Osstell Mentor, Straumann, Ankylos, CellPlus, SLA.

Secondary implant stability outcome of immediate versus late placed variable-thread implants in the maxilla. A retrospective cohort study.

BACKGROUND: The healing of xenograft augmentated intra-alveolar gaps following immediate implant placement (IMIP) after tooth extraction is likely to differ in time and density compared to the native bone part that directly contacts the implant. MATERIAL AND METHODS: Secondary implant stability (SIS) data recorded 2-3 months following a late implant placement protocol (LIP) (n= 43) and 6-8 months following an immediate implant placement protocol (IMIP) (n=33) of variable-thread implants (Nobel Active™) in the maxilla were retrospectively collected from files of 63 patients (42 females, 21 males). Statistical analysis was performed using a generalized estimating equation model (GEE). Data split-up according to implant diameter (RP, Ø= 4.3mm) , narrow platform (NP, Ø= 3.5mm) was adopted. RESULTS: For NP implants, the mean ISQ (±SD) values were 70.84 (±4.86) in LIP group and 72.41 (±3.89) in the IMIP group. For RP implants, mean ISQ (±SD) values were 73.45 (±8.77) in the LIP group and 75.93 (±5.73) in the IMIP group. Significant effect of treatment modus in favour of the IMIP and gender in favour of males and implant position was noted (p<0.05). CONCLUSIONS: SIS following a IMIP protocol after 6-8 months is comparable to LIP protocol after 2-3 months. A minor ISQ outcome difference in favour of the IMIP protocol can be attributed to a difference in hard tissue alteration during healing of the xenograft part. Key words:Secondary implant stability, RFA, Osstell Mentor, variable thread implants, Nobel Active, Bio-Oss, immediate implant placement, late implant placement, non-submerged healing, gap.

Validation of topographic hybrid single-photon emission computerized tomography with computerized tomography scan in patients with and without nonspecific chronic low back pain. A prospective comparative study.

BACKGROUND CONTEXT: The evidence for the treatment for nonspecific chronic low back pain (ns CLBP) is very weak. Besides the complexity of the pain experience, a good biological marker or tool enabling identification of a pain generator is lacking. Hybrid imaging, combining single-photon emission computerized tomography (SPECT) with computerized tomography (CT) scan, has been proposed as useful in the diagnostic workup of patients with CLBP. PURPOSE: To evaluate the sensitivity of SPECT-CT in patients with ns CLBP (Group I) as compared with patients without CLBP (Group II). STUDY DESIGN: A prospective comparative study. PATIENT SAMPLE: Two hundred patients were enrolled: 96 in Group I and 104 in Group II. OUTCOME MEASURES: Only the physiological measurement of the incidence of hot spots was performed. The hot spots were rated as follows: 0=normal; 1=slightly colored (no hot spot on whole-body bone scan); and 2=clear hot spot (can be identified on the whole-body bone scan and confirmed on SPECT). To analyze the interobserver agreement when using this scoring system, a second independent reading was performed for 50 randomly chosen records. METHODS: Two hundred patients divided into two groups were referred to the department of Medical and Molecular Imaging for a topographic SPECT-CT. The first group consisted of patients with ns CLBP, diagnosed by a neurosurgeon. The control group consisted of patients referred for SPECT-CT for non-spinal conditions. Hot spots were assessed for all patients. A second independent reading, blinded for the results of the first reader, was performed on 25 randomly selected patients in each group. This study was investigator initiated, and no funding was received. None of the authors or their proxies have a potential conflict of interest. RESULTS: The odds of finding a normal image in the control group are 2.05 times higher than in Group I. The sensitivity score equals 2.37, meaning that the probability of detecting a hot spot (levels 1 or 2) is more than two times higher in Group I. When focusing on level 2 hot spots only, this score rises to 7.02, indicative of a high sensitivity. CONCLUSIONS: Single-photon emission computerized tomography with computerized tomography might have potential in the diagnostic workup of patients with ns CLBP, owing to its higher sensitivity when compared with other advanced medical imaging modalities.

Fine grained osseointegrative coating improves biocompatibility of PEEK in heterotopic sheep model.

BACKGROUND AND AIM: Polyetheretherketone (PEEK) materials already have been used successfully in orthopedic and especially spine surgery. PEEK is radiolucent and comparable with bone regarding elasticity. However, PEEK is inert and the adhesion of PEEK implants to bone tissue proceeds slowly because of their relatively low biocompatibility. The aim of the study is to evaluate the effect of titanium and CaP coating on the adhesion of bone tissue. MATERIAL AND METHODS: Six adult sheep (body weight 57.6 ± 3.9 kg) were included in this study. Three different types of cylindrical dowels (12 mm length x 8 mm diameter) were implanted in long bones (tibia and femur): PEEK dowels without coating (the control group), and PEEK dowels with a nanocoating of calcium phosphate (CaP group) or titanium (titanium group). Animals were sacrificed after 6, 12 and 26 weeks. Dowels were explanted for micro CT and histology. RESULTS: Bone implant contact (BIC) ratio was significantly higher in the titanium versus control groups in the 6 to 12 weeks period (p = 0.03). The ratio between bone volume and tissue volume (BV/TV) was significantly higher in titanium versus control in the 6 to 12 weeks period (p = 0.02). A significant correlation between BIC and BV/TV was seen (r = 0.85, p < 0.05). CONCLUSION: Coating of PEEK dowels with a nanocoating of titanium has beneficial effects on adhesion of bone tissue.

Unbiased categorical classification of pediatric sleep disordered breathing.

STUDY OBJECTIVES: To classify pediatric sleep disordered breathing (SDB) using unbiased approaches. In children, decisions regarding severity and treatment of SDB are conducted solely based on empirical observations. Although recognizable entities clearly exist under the SDB spectrum, neither the number of SDB categories nor their specific criteria have been critically defined. DESIGN: Retrospective cohort analysis and random prospective cohort. SETTING: Community and clinical sample. PATIENTS OR PARTICIPANTS: Urban 5- to 9-year-old community children undergoing overnight sleep study (NPSG), and a comparable prospectively recruited clinical SDB sample. INTERVENTIONS: N/a. MEASUREMENTS AND RESULTS: Principal component analysis was used to identify the uniqueness of the polysomnographically derived measures that are routinely used in clinical settings: apnea-hypopnea index, apnea index, obstructive apnea index, nadir SpO2, spontaneous arousal index and respiratory arousal index. These measures were then incorporated using unbiased data mining approaches to further characterize and discriminate across categorical phenotypes. Of 1,133 subjects, 52.8% were habitual snorers. Six categorical phenotypes clustered without any a priori hypothesis. Secondly, a non-hierarchical model that incorporated 6 NPSG-derived measures enabled unbiased identification of algorithms that predicted these 6 severity-based clusters. Thirdly, a hierarchical model was developed and performed well on all severity-based clusters. Classification and predictive models were subsequently cross-validated statistically as well as clinically, using 2 additional datasets that included 259 subjects. Modeling reached approximately 93% accuracy in cluster assignment. CONCLUSIONS: Data-driven analysis of conventional NPSG-derived indices identified 6 distinct clusters ranging from a cluster with normal indices toward clusters with more abnormal indices. Categorical assignment of individual cases to any of such clusters can be accurately predicted using a simple algorithm. These clusters may further enable prospective unbiased characterization of clinical outcomes and of genotype-phenotype interactions across multiple datasets.

Coping styles as moderating the relationships between terrorist attacks and well-being outcomes.

This study aims to explore use of coping strategies among adolescents and their relationships with well being in the context of ongoing terrorism. Furthermore, we aim to explore to what extent coping styles in addition to exposure variables explain well being of adolescents facing ongoing terror. During September 2003, after three years of ongoing terror attacks, 913 Israeli adolescents aged 12-18 years, completed the following questionnaires during regular class sessions: Demographics, Achenbach's Youth Self Report; Exposure to Terror and Post Traumatic Stress (PTS) questionnaire; Adolescent Coping Scale (ACS) and Brief Symptoms Inventory. Adolescents employed mainly problem solving strategies which mean they have the capacity to cope well in spite of stressful events. Emotional focused coping was associated with PTS and mental health problems. Regression analysis of different exposure and coping variables revealed that exposure, appraisal (subjective exposure) and coping styles explained 26-37% of the variance of different psychological problems. The findings highlight the importance of appraisal (subjective exposure) and coping strategies, for understanding adolescents' mental health outcomes. Moreover, these findings are relevant to the development of prevention/intervention programs that facilitate youth's cognitive and emotional adjustments to ongoing trauma risks and terror threats.

Differentiation between dementia and depression among older persons: can the difference between actual and premorbid intelligence be useful?

We wanted to investigate whether the difference between actual and premorbid intelligence can be useful to make an early differentiation between Alzheimer's disease (AD) and depression among elderly. A Dutch version of the National Adult Reading Test (NLV), a measure of premorbid IQ and the Raven Coloured Progressive Matrices (RCPM), a measure of actual intelligence were administered to patients with mild (34) and moderate (27) AD, depressed elderly (36) and healthy control subjects (51). Logistic regression analyses revealed that intellectual decline (i.e. subtracting NLV percentile score from RCPM percentile score) was only able to predict group membership when moderate AD patients were compared to depressed and healthy individuals. Our results indicate that intellectual decline may not be a concomitant of elderly depression. However, the differentiation between mild AD and elderly depression can not be made by means of the difference between premorbid (NLV) and actual (RCPM) intelligence scores.

Multidimensional scaling of pediatric sleep breathing problems and bio-behavioral correlates.

STUDY OBJECTIVES: Complex relationships exist between pediatric sleep disorders and daytime behavior. Using a multidimensional scaling model, we investigated these relationships in 126 children with sleep breathing disorders (SBD). METHOD: Validated questionnaires on nighttime behavior, daytime behavior, and respiratory health were administered to a large number of school children in Belgium. Children who met the criterion of having at least one sleep-related breathing problem (three or more times per week during the past six months) were selected for further analyses. A total of 26 indicators were defined and modeled, including sleep problems, sleep efficiency, sleep environment, sleep enuresis, internalised and externalised behavioral problems, respiratory health of the child and relatives, smoking exposure, and caffeine consumption. RESULTS: From 3,045 questionnaire responses 4.1% of the children were reported to have a SBD symptom. SBD children differed on sleep and health domains from non-SBD children. Furthermore, through scaling of the (dis)similarities among the 26 indicators the SBD child was able to be modeled. By way of an internal analysis of the data-matrix the following indicators were eliminated: sleep correlates, health of the family, and behavior rated by teachers, followed by caffeine intake, drugs, and behavior rated by the parents. This revealed a two-dimensional model, consisting of primary SBD and secondary SBD. CONCLUSION: Children with SBD differ on many domains from children without such disorders and an underlying two-fold SBD concept was found. Firstly, the SBD-indicator positioned in between investigated correlates with disorders of initiating and maintaining sleep and sleep hyperhydrosis on one hand and with respiratory-related illnesses on the other; this was labeled primary SBD. Secondly, the SDB-indicator not closely associated with any of the investigated correlates can be interpreted as secondary SBD.

Odds, prevalence and predictors of sleep problems in school-age normal children.

The objectives of the study were to describe the prevalence, odds, and predictors of 36 paediatric sleep behaviours and describe their coexistence in a school-age normal population. The design was community-based questionnaire survey of sleep-wake patterns, sleep environment, and 36 sleep behaviours indicative of six sleep disorder-subscales using the Health-Behaviour Questionnaire. A caregivers' report of 3045 children aged 6-13 years in Belgium constituted the participants. Prevalence of each sleep behaviour was calculated. Log-linear modelling within and between the sleep disorder-subscales was used to screen for coexistence. The effect size of selected night-time parameters to the likelihood of sleep behaviours and disorder-subscale was expressed as odds ratios via logit regression analysis. Significant differences in sleep-wake patterns were found between weekday and weekend. Ranking by odds showed that: (1) sleep problems such as 'tired when waking up', 'repetitive limb movements', 'going to bed reluctantly', and 'sleep paralysis' and; (2) the disorder-subscale 'excessive somnolence' are common in children. Coexistences within and between disorder-subscales of sleep problems are evident in a school-age, normal population. These results suggest that disorders of excessive somnolence (DES) are highly prevalent in a non-clinical sample of school-age children. Furthermore, sleep-onset latency and a noisy, not well-darkened room are predictive towards the odds for exhibiting sleep problems and disorders. It is advocated that more information on the importance of good sleep-wake hygiene should reach parents and children.

Pediatric sleep disorders: exploratory modulation of their relationships.

STUDY OBJECTIVES: This study explores relationships between clinically encountered sleep problems in children. DESIGN: The Sleep Disturbance Scale for Children (SDSC) (Bruni et al 1996), which screens 26 sleep problems and results in 6 sleep disorder-subscales, was used as core in a larger health-behavior questionnaire (HBQ). PARTICIPANTS: Caregivers of 3045 6- to 12-year-olds filled out the HBQ. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: 21 SDSC-items plus 15 new sleep items were selected. Via structural equation modelling we explored (1) relations within and between disorder-subscales, (2) relations between the disorder-subscales with 3 indexes added (i.e., sleep efficiency index, sleep environment index, and sleep enuresis) and (3) relations of the disorder-subscales to their categorization: dyssomnia and parasomnia, without and with the indexes. CONCLUSIONS: The final model had a satisfying fit and approximates the Association of Sleep Disorders Centers' classification. Each disorder-subscale can be applied individually. However, some items are statistically of low value. For that reason, the use as the inference of relations between such items should be cautious. Adding the 3 indexes improved the fit of the model. The complexity of 'sleep enuresis' was especially revealed. For the practicing care provider, as for researchers, the statistical model proposed could be a valuable directive in the diagnostic classification process of pediatric sleep problems.