[The 3D-printed surgical guides used during genioplasty]. / De 3D-geprinte zaag- en repositiemal voor een kinplastiek.

Genioplasty is a seemingly simple procedure performed to correct the bony chin. The results of the procedure are, however, strongly correlated with the experience of the surgeon. 3D-printed surgical guides could act as a transfer modality to translate the preoperative planning directly into the achieved result. Prospective studies evaluating the usefulness of the 3D-printed surgical guides have not yet been carried out and consensus regarding the best design is lacking. In order to become more familiar with working with surgical guides, a genioplasty using 3D-printed surgical guides was performed. The postoperative analysis of the achieved result showed minor differences compared to preoperative planning. Surgical guides have the potential to improve the accuracy and predictability of genioplasty. The design should be further refined and the added value of the guides should be confirmed by means of prospective research.

Critical appraisal of patient-specific implants for secondary post-traumatic orbital reconstruction.

In orbital reconstruction, a patient-specific implant (PSI) may provide accurate reconstruction in complex cases, since the design can be tailored to the anatomy. Several design options may be embedded, for ease of positioning and precision of reconstruction. This study describes a cohort of 22 patients treated for secondary orbital reconstruction with a PSI; one patient received two PSI. The preoperative clinical characteristics and implant design options used are presented. When compared to preoperative characteristics, the postoperative clinical outcomes showed significant improvements in terms of enophthalmos (P < 0.001), diplopia (P < 0.001), and hypoglobus (P = 0.002). The implant position in all previous reconstructions was considered inadequate. Quantitative analysis after PSI reconstruction showed accurate positioning of the implant, with small median and 90th percentile deviations (roll: median 1.3°, 90th percentile 4.6°; pitch: median 1.4°, 90th percentile 3.9°; yaw: median 1.0°, 90th percentile 4.4°; translation: median 1.4 mm, 90th percentile 2.7 mm). Rim support proved to be a significant predictor of roll and rim extension for yaw. No significant relationship between design options or PSI position and clinical outcomes could be established. The results of this study show the benefits of PSI for the clinical outcomes in a large cohort of secondary post-traumatic orbital reconstructions.

Registration-free workflow for electromagnetic and optical navigation in orbital and craniofacial surgery.

The accuracy of intra-operative navigation is largely dependent on the intra-operative registration procedure. Next to accuracy, important factors to consider for the registration procedure are invasiveness, time consumption, logistical demands, user-dependency, compatibility and radiation exposure. In this study, a workflow is presented that eliminates the need for a registration procedure altogether: registration-free navigation. In the workflow, the maxillary dental model is fused to the pre-operative imaging data using commercially available virtual planning software. A virtual Dynamic Reference Frame on a splint is designed on the patient's fused maxillary dentition: during surgery, the splint containing the reference frame is positioned on the patient's dentition. This alleviates the need for any registration procedure, since the position of the reference frame is known from the design. The accuracy of the workflow was evaluated in a cadaver set-up, and compared to bone-anchored fiducial, virtual splint and surface-based registration. The results showed that accuracy of the workflow was greatly dependent on tracking technique used: the workflow was the most accurate with electromagnetic tracking, but the least accurate with optical tracking. Although this method offers a time-efficient, non-invasive, radiation-free automatic alternative for registration, clinical implementation is hampered by the unexplained differences in accuracy between tracking techniques.

A three-dimensional statistical shape model of the growing mandible.

Mandibular growth and morphology are important topics in the field of oral and maxillofacial surgery. For diagnostic and planning purposes, a normative database or statistical shape model of the growing mandible can be of great benefit. A collection of 874 cadaveric children's mandibles with dental age between 1 and 12 years old were digitized using computed tomography scanning and reconstructed to three-dimensional models. Point correspondence was achieved using iterative closest point and coherent point drift algorithms. Principal component analysis (PCA) was applied to find the main modes of variation in the data set. The average mandible was presented, along with the first ten PCA modes. The first mode explained 78% of the total variance; combining the first ten modes accumulated to 95% of the total variance. The first mode was strongly correlated with age and hence, with natural growth. This is the largest study on three-dimensional mandibular shape and development conducted thus far. The main limitation is that the samples lack information such as gender and cause of death. Clinical application of the model first requires validation with contemporary samples.

Surgical instrument to improve implant positioning in orbital reconstruction: a feasibility study.

Adequate positioning of an orbital implant during orbital reconstruction surgery is essential for restoration of the pre-traumatised anatomy, but visual appraisal of its position is limited by the keyhole access and protruding soft tissues. A positioning instrument that attaches to the implant was designed to provide feedback outside the orbit. The goal of this study was to evaluate the accuracy of placement with the instrument and compare it with the accuracy of placement by visual appraisal. Ten orbits in five human cadaver heads were reconstructed twice: once using visual appraisal and once using the instrument workflow. No significant improvement was found for the roll (5.8° vs 3.4°, respectively, p=0.16), pitch (2.1° vs 1.5°, p=0.56), or translation (2.9 mm vs 3.3 mm, p=0.77), but the yaw was significantly reduced if the instrument workflow was used (15.3° vs 2.9°, p=0.02). The workflow is associated with low costs and low logistical demands, and may prevent outliers in implant positioning in a clinical setting when intraoperative navigation or patient-specific implants are not available.

Virtual splint registration for electromagnetic and optical navigation in orbital and craniofacial surgery.

In intra-operative navigation, a registration procedure is performed to register the patient's position to the pre-operative imaging data. The registration process is the main factor that determines accuracy of the navigation feedback. In this study, a novel registration protocol for craniofacial surgery is presented, that utilizes a virtual splint with marker points. The accuracy of the proposed method was evaluated by two observers in five human cadaver heads, for optical and electromagnetic navigation, and compared to maxillary bone-anchored fiducial registration (optical and electromagnetic) and surface-based registration (electromagnetic). The results showed minimal differences in accuracy compared to bone-anchored fiducials at the level of the infra-orbital rim. Both point-based techniques had lower error estimates at the infraorbital rim than surface-based registration, but surface-based registration had the lowest loss of accuracy over target distance. An advantage over existing point-based registration methods (bone-anchored fiducials, existing splint techniques) is that radiological imaging does not need to be repeated, since the need for physical fiducials to be present in the image volume is eradicated. Other advantages include reduction of invasiveness compared to bone-achnored fiducials and a possible reduction of human error in the registration process.

Stability of fixation methods in large mandibular advancements after sagittal split ramus osteotomy: an in vitro biomechanical study.

Sagittal split ramus osteotomy (SSRO) with large mandibular advancements is a common surgical procedure and could be indicated for patients with sleep apnoea. As a large variety of fixation methods is used for the stabilisation of SSRO, a biomechanical test model was used to analyse which fixation technique was most stable. For this in vitro study, 80 polyurethane hemimandibles with a prefabricated SSRO were used as substrates. Loads in Newtons were recorded at displacements of the mandibular incisive edge at 1mm, 3mm and 5mm. The samples were divided into two groups: mandibular advancements of 10mm and 15mm. In both groups, four fixation techniques were used: (A) one four-hole miniplate; (B) two four-hole miniplates; (C) one four-hole miniplate plus one bicortical screw; and (D) three bicortical screws in an inverted-L arrangement. In group 1, three bicortical screws resulted in the best stability, and in group 2, two miniplates resulted in the best stability. The use of two miniplates did not show significant differences between both groups. Other fixation methods showed more stability with 10mm advancements. This study therefore suggests that in SSRO with advancements exceeding 10mm, the use of two miniplates is the optimal means of providing rigid fixation.

Determination of intra-oral surface areas by cone-beam computed tomography analysis and their relation with anthrometric measurements of the head.

PURPOSE: Determination of intra-oral surface areas might contribute to our understanding of the physiology of the oral cavity and oral diseases. In previous studies, the intra-oral surface area was determined using a laborious and technically challenging method. Our aim was to develop an easy and non-invasive method to determine the intra-oral surface areas. METHODS: In this study, we used cone-beam computed tomography (CBCT) and digital analysis in 20 human cadavers to determine various intra-oral surface areas, based on digital segmentation. Next, we explored whether there was a relationship between various intra-oral surface areas and anthropometric measurements of the head using Pearson correlation coefficient. RESULTS: Using CBCT and digital analysis, it was possible to determine various intra-oral surface areas. On average, the total intra-oral surface area was 173 ± 19 cm2. Moderate, statistical significant correlations were observed between (1) the length of the head and the palatal surface area, as well as (2) the depth of the head and the surface area of the tongue. These correlations suggest the feasibility of estimating intra-oral surface areas without relying on CBCT imaging. CONCLUSIONS: This study presents a technique for measuring the intra-oral surface areas by CBCT imaging in combination with digital analysis. The results of this study suggest that anthropometric measurements of the head might be used to estimate the surface areas of the palate and tongue.

Implant-oriented navigation in orbital reconstruction part II: preclinical cadaver study.

In orbital reconstruction, the acquired position of an orbital implant can be evaluated with the aid of intraoperative navigation. Feedback of the navigation system is only obtained after positioning of the implant: the implant's position is not tracked in real time during positioning. The surgeon has to interpret the navigation feedback and translate it to desired adjustments of the implant's position. In a previous study, a real-time implant-oriented navigation approach was introduced and the system's accuracy was evaluated. In this study, this real-time navigation approach was compared to a marker-based navigation approach in a preclinical set-up. Ten cadavers (20 orbital defects) were reconstructed twice, by two surgeons (total: 80 reconstructions). Implant positioning was significantly improved in the real-time implant-oriented approach in terms of roll (2.0° vs. 3.2°, P=0.03), yaw (2.2° vs. 3.4°, P=0.01) and translation (1.3mm vs. 1.8mm, P=0.005). Duration of the real-time navigation procedure was reduced (median 4.5 min vs. 7.5 min). Subjective appreciation of the navigation technique was higher for real-time implant-oriented navigation (mean 7.5 vs. 9.0). Real-time implant-oriented navigation feedback provides real-time, intuitive feedback to the surgeon, which leads to improved implant positioning and shortens duration of the navigation procedure.

All-cause mortality with current and past use of antidepressants or benzodiazepines after major osteoporotic and hip fracture.

In the first year, after an osteoporotic fracture of a hip, forearm, upper arm, or spine, the dispensing rates of antidepressants and benzodiazepines increased significantly. After those fractures, recent and past use of antidepressants and benzodiazepines was associated with increased all-cause mortality; current use was not associated with mortality risk. INTRODUCTION: It remains unclear to what extent use of antidepressants and benzodiazepines is associated with mortality risk after a major osteoporotic fracture (MOF). We aimed to study the cumulative use of antidepressants and benzodiazepines during the year after MOF or hip fracture (HF) and whether the use was associated with mortality. METHODS: A cohort study was performed within the Dutch PHARMO Database Network including all patients aged 65+ with a first record of MOF (hip, humerus, forearm, and clinical vertebral fracture) between 2002 and 2011. Data were analyzed using Cox regression models, adjusted for comorbidities, and concomitant medication use and broken down to index fracture type. RESULTS: A total of 4854 patients sustained a first MOF, of whom 1766 patients sustained a HF. Mean follow-up was 4.6 years, divided in 30-day periods. The cumulative antidepressant and benzodiazepine use during the first year after MOF increased from 10.6 to 14.7% and from 24.0 to 31.4%, respectively. Recent (31-92 days before each follow-up period) and past use (> 92 days before) of antidepressants and benzodiazepines after MOF or HF was associated with an increased all-cause mortality risk but current use (< 30 days before) was not. CONCLUSION: There is a considerable increase in dispensing rate of antidepressants and benzodiazepines in the first year after a MOF. Recent and past use of these medications was associated with all-cause mortality. The finding that current use was not associated with mortality should be further explored and may probably be explained by the healthy survivor's bias.

Association between use of antidepressants or benzodiazepines and the risk of subsequent fracture among those aged 65+ in the Netherlands.

This is the first study to examine the association between antidepressant and benzodiazepine use following a MOF and risk of subsequent fracture in those 65+. Using national data, drug use following MOF showed that the 1-year fully adjusted risk of subsequent MOF in those on antidepressants was more than doubled. INTRODUCTION: We evaluated the association between the use of antidepressants or benzodiazepines and the risk of a subsequent major osteoporotic fracture. METHODS: A cohort study was performed using the Dutch PHARMO Database Network. Between 2002 and 2011, a total of 4854 patients sustained a first major osteoporotic fracture after the age of 65 years, of which 1766 sustained a hip fracture. Incidence rates and adjusted hazard ratios were calculated using Cox proportional hazards models. RESULTS: Within 1 year following a major osteoporotic fracture, 15% (95% CI 13.7-15.7) and 31% (95% CI 30.1-32.8) of patients were dispensed an antidepressant or benzodiazepine, respectively. Current use of antidepressants in the first year following a major osteoporotic fracture was associated with subsequent fracture (adjusted HR 2.17 (95% CI 1.37-3.43)). Recent and past use of antidepressants were also associated with an increased risk of subsequent fracture. When the complete follow-up period was included, only the current use of antidepressants was associated with subsequent fracture following a major osteoporotic fracture (adjusted HR 1.48; 95% CI 1.06-2.06). Current benzodiazepine use was not associated with an increased risk of fracture within 1 year following a major osteoporotic fracture (adjusted HR 1.18; 95% CI 0.76-1.81) or during the complete follow-up period (adjusted HR 1.18; 95% CI 0.90-1.55). CONCLUSION: This study provides evidence that antidepressants should be used with caution following a major osteoporotic fracture. It provides needed insights that can be used to inform clinicians when assessing subsequent fracture risk in patients.

The epidemiology of mortality after fracture in England: variation by age, sex, time, geographic location, and ethnicity.

One-year mortality following a fracture was greater for men compared to women, varied markedly between regions in England with the lowest rates in the London region, and was higher among black women compared to white women. The excess in mortality did not change during the study period. INTRODUCTION: Fractures are associated with increased mortality. With the shift towards an increasingly elderly demography, and so increasing numbers of fractures, the impact of such events on mortality is of key public health importance. Therefore, we aimed to present up-to-date mortality rates following fracture in England. METHODS: This was a population-based study within the Clinical Practice Research Datalink, linked to death certificates (1 January 2001 to 31 December 2011). Subjects were followed from their first fracture (hip, wrist, humerus, clinical spine, ribs, or pelvis) until death for up to 1 year. Rate ratios (RRs) were estimated for 1-year mortality, stratified by sex, 5-year age categories, ethnicity, and geographical region. Excess mortality was presented as standardized mortality ratios (SMRs). RESULTS: One-year mortality following fracture increased with age and was higher for men than women. Black women (RR 1.77; 95 % CI 1.00-3.12) and women of "other" ethnicity (RR 1.59, 95 % CI 1.16-2.16) were at higher risk of death when compared to white women. Mortality was higher among women in almost all regions when compared to the London region, with the highest risk in the East Midlands (37 % higher). The 1-year mortality risk was more than 3-fold higher after fracture as compared to the general population (adjusted SMR: 3.15, 95 % CI 3.09-3.26) and did not change during the study period. Major causes of death were neoplasms, respiratory diseases, and circulatory diseases. CONCLUSION: This study provides up-to-date mortality outcomes following fracture in England and will aid allocation of healthcare provision to those at greatest need.

Anti-osteoporosis drug prescribing after hip fracture in the UK: 2000-2010.

UNLABELLED: The probability of initiating with anti-osteoporosis therapy increased from 7 % in 2000 to 46 % in 2010. This improvement was greater for patients over the age of 75 years. Men, those overweight, having dementia or exposed to antipsychotics, sedatives/hypnotics or opioid analgesics were significantly less likely to receive anti-osteoporosis drugs. INTRODUCTION: The objective of this study was to examine trends and determinants of anti-osteoporosis drug prescribing after hip fracture in the UK between 2000 and 2010. METHODS: Data were extracted from the UK Clinical Practice Research Datalink for patients ≥50 years who had a first hip fracture between 2000 and 2010 and who did not currently (≤6 months prior) receive anti-osteoporosis drugs (bisphosphonates, strontium ranelate, parathyroid hormone, calcitonin and raloxifene) (n = 27,542). The cumulative incidence probability of being prescribed anti-osteoporosis drugs within 1 year after hip fracture was estimated by Kaplan-Meier life-table analyses. Determinants for treatment initiation were estimated by Cox proportional hazards models. RESULTS: The probability of being prescribed any anti-osteoporosis drug after hip fracture increased from 7 % in 2000 to 46 % in 2010. This trend was more marked in patients ≥75 years. The increase in prescribing of anti-osteoporosis drugs was complemented by a similar increase in vitamin D/calcium provision. Cumulative incidence of receiving anti-osteoporosis therapy was greater at any given point in time in women (8 % in 2000, 51 % in 2010) compared to men (4 % in 2000, 34 % in 2010). In addition to male gender, multivariable Cox regression identified reduced likelihood of receiving anti-osteoporosis drugs for those being overweight, having dementia and exposed to psychotropic drugs (antipsychotics, sedatives/hypnotics) or opioid analgesics. CONCLUSION: Although the prescribing of anti-osteoporosis drugs after hip fracture has increased substantially since 2000, the overall rate remained inadequate, particularly in men. With the continuing increase in the absolute number of hip fractures, further research should be made into the barriers to optimise osteoporosis management.

Long-term persistence with anti-osteoporosis drugs after fracture.

UNLABELLED: Long-term persistence with anti-osteoporosis drugs and determinants for discontinuation among fracture patients were examined. Persistence was 75.0 and 45.3 % after 1 and 5 years, respectively. Those aged ≥80 years were at increased risk of early discontinuation. Within 1 year after discontinuation, 24.3 % restarted therapy, yet 47.0 % persisted for 1 year. INTRODUCTION: The risk of osteoporotic fracture can effectively be reduced with use of anti-osteoporosis drugs. However, little is known about persistence with these drugs after fracture where subsequent fracture risk is high. The aims were to determine long-term persistence with anti-osteoporosis drugs among fracture patients, including its determinants, and to describe restart and subsequent persistence. METHODS: A cohort study was conducted within the Dutch PHARMO Database Network. Patients aged ≥50 years (n = 961) who received anti-osteoporosis drugs within 1 year after fracture, but not in the preceding year, were included (2002-2011). Persistence (defined as the proportion on treatment) and the proportion restarting after discontinuation were estimated using Kaplan-Meier analyses. Time-dependent Cox regression was used to identify determinants of non-persistence including age, sex, initial dosage regime, fracture type, comorbidities, and drug use. RESULTS: Persistence with anti-osteoporosis drugs was 75.0 % (95 % confidence interval (CI) 72.0-77.7) and 45.3 % (95 % CI 40.4-50.0) after 1 and 5 years, respectively. A significant determinant of non-persistence was age ≥80 years (reference 50-59 years: adjusted hazard ratio [adj. HR] 1.65; 95 % CI 1.15-2.38). This effect was not constant over time (≤360 days following initiation: adj. HR 2.07; 95 % CI 1.27-3.37; >360 days: adj. HR 1.08; 95 % CI 0.62-1.88). Within 1 year after discontinuation, 24.3 % (95 % CI 20.1-29.2) restarted therapy, yet 47.0 % persisted for 1 year. CONCLUSIONS: This study identified suboptimal persistence with anti-osteoporosis drugs among fracture patients. Major target groups for measures aimed to improve persistence may be those aged >80 years and those restarting therapy.

The risk of major and any (non-hip) fragility fracture after hip fracture in the United Kingdom: 2000-2010.

UNLABELLED: The risk of a subsequent major or any fracture after a hip fracture and secular trends herein were examined. Within 1 year, 2.7 and 8.4% of patients sustained a major or any (non-hip) fracture, which increased to 14.7 and 32.5% after 5 years. Subsequent fracture rates increased during the study period both for major and any (non-hip) fracture. INTRODUCTION: Hip fractures are associated with subsequent fractures, particularly in the year following initial fracture. Age-adjusted hip fracture rates have stabilised in many developed countries, but secular trends in subsequent fracture remain poorly documented. We thus evaluated secular trends (2000-2010) and determinants for the risk of a subsequent major (humerus, vertebral, or forearm) and any (non-hip) fracture after hip fracture. METHODS: Patients ≥50 years with a hip fracture between 2000 and 2010 were extracted from the UK Clinical Practice Research Datalink (n = 30,516). Incidence rates, cumulative incidence probabilities, and adjusted hazard ratios (aHRs) were calculated. RESULTS: Within 1 year following hip fracture, 2.7 and 8.4% of patients sustained a major or any (non-hip) fracture, which increased to 14.7 and 32.5% after 5 years, respectively. The most important risk factors for a subsequent major fracture within 1 year were the female gender [aHR 1.90, 95% confidence interval (CI) 1.51-2.40] and a history of secondary osteoporosis (aHR 1.54, 95% CI 1.17-2.02). The annual risk increased during the study period for both subsequent major (2009-2010 vs. 2000-2002: aHR 1.44, 95% CI 1.12-1.83) and any (non-hip) facture (2009-2010 vs. 2000-2002: aHR 1.80, 95% CI 1.58-2.06). CONCLUSION: The risk of sustaining a major or any (non-hip) fracture after hip fracture is small in the first year. However, given the recent rise in secondary fracture rates and the substantial risk of subsequent fracture in the longer term, fracture prevention is clearly indicated for patients who have sustained a hip fracture.

Increase in prophylaxis of glucocorticoid-induced osteoporosis by pharmacist feedback: a randomised controlled trial.

UNLABELLED: The aim of this study was to determine whether feedback by pharmacists to prescribers of patients eligible for glucocorticoid-induced osteoporosis prophylaxis would stimulate the prescribing of osteoporosis prophylaxis. The intervention did not significantly increase the prescribing of bisphosphonates in the total study population, but a significant increase was seen in men and in the elderly. However, the proportion of bisphosphonate-treated patients remained low. INTRODUCTION: The aim of this study was to determine whether feedback by pharmacists to prescribers of patients eligible for glucocorticoid-induced osteoporosis prophylaxis (GIOP) would stimulate the implementation of the Dutch GIOP guideline. METHODS: This randomised controlled trial included 695 patients who were dispensed ≥675 mg prednisone equivalents without a concomitant bisphosphonate prescription within 6 months before baseline. Pharmacists were asked to contact the physicians of GIOP-eligible patients in the intervention group to suggest osteoporosis prophylaxis. The primary endpoint was a bisphosphonate prescription. Secondary endpoints were a prescription of calcium supplements, vitamin D or any prophylactic osteoporosis drug (bisphosphonate, calcium supplements, vitamin D). RESULTS: The group assigned to the intervention was slightly younger than the control group (68.7 ± 15.4 vs. 65.9 ± 16.9 years, p = 0.02) and used hydrocortisone more often (7.0% vs. 3.1%, p = 0.02). Within 6 months, the intervention did not significantly increase the prescribing of bisphosphonates (11.4% after intervention vs. 8.0% for controls; hazard ratio [HR] 1.47, 95% confidence interval [CI] 0.91-2.39). However, subgroup analyses showed a significant increase for the primary endpoint in men (12.8% vs. 5.1%, HR 2.53, 95% CI 1.11-5.74) and patients ≥70 years (13.4% vs. 4.9%, HR 2.88, 95% CI 1.33-6.23). The prescribing of calcium and vitamin D was not significantly altered. CONCLUSION: This study showed that active identification of patients eligible for GIOP by pharmacists did not significantly increase the prescribing of bisphosphonates in the total study population, but there was an increase in men and the elderly. However, the proportion of GIOP-treated patients remained low.