Statistical shape analysis and principal component analysis of the clavicle

\u22The chief use of the clavicle is to hold the shoulder blade at the proper distance from the breastbone, since motion of the shoulder would be hindered if the two came close together, as seen in four-footed animals that can use their forefeet only for walking, and not in the way that men need their hands.\u22 - Therselben, 1790 Although anthropometric work on the clavicle by Broca dates as far back as 1869 according to Voisin1, the role of the clavicle has been described more than 200 years ago by Therselben. While one study stated that the clavicle is the most frequently fractured bone of the human skeleton2, data collected in Malmo, Sweden between 1952 and 1987 showed that fractures of the clavicle only accounted for 4% of all fractures, but that this represented 35% of all fractures in the shoulder region3. Other studies have shown similar results, estimating that clavicular fractures account for 5 to 10% of all fractures4,5, and 44% of all injuries to the shoulder girdle6. According to Wheeless\u27 Online Textbook of Orthopaedics, fractures to the middle third are the most common in adults and children, accounting for account for 80% while fractures to the lateral third are seen in 15% with the remaining 5% affecting the medial third. Numerous studies have verified this, statingthat 80% of clavicular fractures occur in the middle third, 10 to 18% in the lateral third and 2 to 10% in the medial third 7,8,9,10,11. This can be explained by a number of facts. Firstly, that the narrowest part of the clavicle is at the meeting point of the sternal convexity and the acromial concavity, which is the location of the majority of clavicle fractures2. Second of all, there is a significant decrease in bone density at the transition from middle to lateral thirds of the clavicle, explaining the increased frequency of fractures occurring in the middle and lateral thirds2. It has also been previously shown that the mid-portion of the clavicle is the thinnest and narrowest part of the bone and represents a transitional region of the bone, both in curvature and cross-sectional anatomy, making it a mechanically weak area that is most likely to fracture12. In terms of location, the sternoclavicular and acromioclavicular joints hold the clavicle in its anatomical position with the latter having been described as a \u27keystone\u27 link between the scapula and clavicle13. Its integrity plays an important role in the movement of the shoulder girdle. The construct of the ACJ makes it a very strong joint able to tolerate a significant amount of force before disruption. This explains that in comparison to clavicular fractures, injuries to the ACJ account for approximately only 12% of those to the shoulder girdle seen in clinical practice14. Much higher incidences are seen in contact sports. In rugby, ACJ injuries have been shown to account for 32% of shoulder injuries15 and in American football they are the most common injury to the shoulder16. Even in non-contact sports such as recreational skiing, about 20% of injuries to the shoulder girdle involve the ACJ17. With the majority of injuries to the ACJ seen in young males, the same applies to fractures of the clavicle18. The main aim in treating fractures of the clavicle is to provide comfort and pain relief. Management options for both ACJ injuries as well as fractures of the clavicle vary widely, spanning from conservative treatment to fixation requiring surgical intervention with the latter including a variety of options from minimally invasive techniques19 to the application of a fixation plate. Whenever a fixation implant is to be selected, several factors drive the decision. The fit on bone of any fixation plate has a direct impact on the strength of the construct. However, current clavicular implants overlook the variations in geometry of the bone. In 2007, a paper describing the anatomy of the clavicle stated that gender specific anatomical features should be taken into consideration when performing intramedullary fixation of the clavicle2. While the length, diameters and curvature of the clavicles measured were based on 196 embalmed specimens, cortical bone thickness and the medullary canal diameter were determined using only 10 fresh specimens. In a more recent article, it has been reported that cortical bone thickness and bone shape of the clavicle have large effects on bone responses until failure and on fracture location20. This study emphasized the need for geometrical personalization of clavicle models in order to consider various age, gender and shape discrepancies. However, the radiological aspect of this study was based only on six clavicles with the biomechanical testing based on 18 clavicles from nine subjects with a mean age of 78. From a clinical standpoint, a larger number and much younger population should be studied, considering that fractures to the clavicle are most commonly seen in the twenties although comminuted fractures may be more common in the third and forth decades. The relationship between clavicular length restoration post-fracture and functional outcome remains controversial. Some studies have concluded no observable reduction in shoulder function 21,22,23, while others have stressed the importance of restoration of clavicular length post-fracture 24,25. Previous literature has also stated that up to 30% of patients treated non-operatively develop unsatisfactory outcomes clinically, radiologically, and subjectively because of bony shortening, malunion, poor alignment or deforrnity 24,25,26,27. In another study of outcome after closed treatment of the fractured clavicle, the majority of patients were not satisfied with the cosmetic deformity and 40% complained of impaired function28. Although most fractures of the clavicle have a good prognosis and can be managed conservatively, the role of surgical intervention and its importance must not be forgotten. In the literature, some studies focused on clavicle tests 20,29,30,31, while others focused on geometry 2,12,20,32. However, these studies had very small sample sizes as previously stated. As plate and intramedullary fixation are accepted and widely used methods of treatment, a study analyzing the shape and looking into the necessity for modifying modern implants in order to optimize fixation based on personalized bony geometry has much clinical relevance with regard to the management of clavicular fractures. One recent study set out to characterize variations in clavicular anatomy and determine the clinical applicability of an anatomic precontoured clavicular plate designed for fracture fixation33. However, the authors themselves stated that their main limitation was that it was a two-dimensional analysis of plate fit rather than a three-dimensional analysis. By noting the shortcomings of the abovementioned studies, this thesis focuses on the anatomy of the clavicle and the analysis and application of it to the design of currently available clavicle fixation plates in both a systematic and structured manner

An application of principal component analysis to the clavicle and clavicle fixation devices

BACKGROUND: Principal component analysis (PCA) enables the building of statistical shape models of bones and joints. This has been used in conjunction with computer assisted surgery in the past. However, PCA of the clavicle has not been performed. Using PCA, we present a novel method that examines the major modes of size and three-dimensional shape variation in male and female clavicles and suggests a method of grouping the clavicle into size and shape categories. MATERIALS AND METHODS: Twenty-one high-resolution computerized tomography scans of the clavicle were reconstructed and analyzed using a specifically developed statistical software package. After performing statistical shape analysis, PCA was applied to study the factors that account for anatomical variation. RESULTS: The first principal component representing size accounted for 70.5 percent of anatomical variation. The addition of a further three principal components accounted for almost 87 percent. Using statistical shape analysis, clavicles in males have a greater lateral depth and are longer, wider and thicker than in females. However, the sternal angle in females is larger than in males. PCA confirmed these differences between genders but also noted that men exhibit greater variance and classified clavicles into five morphological groups. DISCUSSION AND CONCLUSIONS: This unique approach is the first that standardizes a clavicular orientation. It provides information that is useful to both, the biomedical engineer and clinician. Other applications include implant design with regard to modifying current or designing future clavicle fixation devices. Our findings support the need for further development of clavicle fixation devices and the questioning of whether gender-specific devices are necessary

Laparoscopic Nissen fundoplication post-oesophageal stenting: an unusual case.

Laparoscopic Nissen fundoplication post-oesophageal stenting is uncommon and yet to be reported. We report the case of a 57-year-old palliative lady who underwent surgery for symptomatic relief of severe gastrooesophageal reflux post-oesophageal stenting. Surgery was carried out successfully with no complications. On the evening post-surgery she was able to lie supine for the first time in months without symptoms of reflux. In conclusion, surgery is still valuable and may play an important role, even in a palliative setting

The social construction of 'dowry deaths'

The classification of cause of death is real in its consequences: for the reputation of the deceased, for her family, for those who may be implicated, and for epidemiological and social research and policies and practices that may follow from it. The study reported here refers specifically to the processes involved in classifying deaths of women from burns in India. In particular, it examines the determination of 'dowry death', a class used in India, but not in other jurisdictions. Classification of death is situated within a framework of special legal provisions intended to protect vulnerable women from dowry-related violence and abuse. The findings are based on 33 case studies tracked in hospital in real time, and interviews with 14 physicians and 14 police officers with experience of dealing with burns cases. The formal class into which any given death is allocated is shown to result from motivated accounting processes representing the interests and resources available to the doctors, victims, victim families, the victim's husband and his family, and ultimately, the police. These processes may lead to biases in research and to injustice in the treatment of victims and alleged offenders. Suggestions are made for methods of ameliorating the risks

Perceptions of gender-based violence around public toilets in Mumbai slums

The lack of adequate public toilets and associated gender-based violence around their use is a matter of concern in many developing countries and has recently come to the forefront of the political agenda and media discourse in India. Previous research suggests the absence of lighting, inadequate provision of basic sanitation, poor design and siting of toilets, and lack of police presence in slums as facilitators for violence against women. However, the evidence is often anecdotal and usually unsystematic. The exact extent of crimes against women in these circumstances is unknown because unsurprisingly women in slums rarely report crimes to the police, either due to fear or lack of access. The research reported in this paper gauges women’s perception and experience of crime and violence around different types of public toilets in two slums areas in Mumbai, India. A survey of 142 households indicated that although women’s fear of crime was higher than their actual experience, the perception of insecurity was not uniform for all toilet types and locations. Findings also indicated that there was at least minimal provision of toilet facilities, basic security features, water, and electric supply in the research sites. Furthermore, greater police presence and previous contact with the police in one slum area led for greater confidence in reporting offences to the police as compared to the other. Overall, better provision of lighting and regular police patrols were considered by a majority of those surveyed to reduce fear of crime around toilets

Conflict, Crisis, and Abuse in Dharavi, Mumbai: Experiences from Six Years at a Centre for Vulnerable Women and Children

Nayreen Daruwalla and colleagues describe the Centre for Vulnerable Women and Children, which serves clients coping with crisis and violence in the urban setting of Dharavi, Mumbai

A large animal model of RDH5-associated retinopathy recapitulates important features of the human phenotype

Pathogenic variants in retinol dehydrogenase 5 (RDH5) attenuate supply of 11-cis-retinal to photoreceptors leading to a range of clinical phenotypes including night blindness due to markedly slowed rod dark adaptation and in some patients, macular atrophy. Current animal models (such as Rdh5-/- mice) fail to recapitulate the functional or degenerative phenotype. Addressing this need for a relevant animal model we present a new domestic cat model with a loss-of-function missense mutation in RDH5 (c.542G > T; p.Gly181Val). As with patients, affected cats have a marked delay in recovery of dark adaptation. Additionally, the cats develop a degeneration of the area centralis (equivalent to the human macula). This recapitulates the development of macular atrophy that is reported in a subset of patients with RDH5 mutations and is shown in this paper in 7 patients with biallelic RDH5 mutations. There is notable variability in the age at onset of the area centralis changes in the cat, with most developing changes as juveniles but some not showing changes over the first few years of age. There is similar variability in development of macular atrophy in patients and while age is a risk factor, it is hypothesized that genetic modifying loci influence disease severity, and we suspect the same is true in the cat model. This novel cat model provides opportunities to improve molecular understanding of macular atrophy and test therapeutic interventions for RDH5-associated retinopathies

Validity of the Walter Reed Visual Assessment Scale to measure subjective perception of spine deformity in patients with idiopathic scoliosis

BACKGROUND: The Walter Reed Visual Assessment Scale (WRVAS) was designed to allow idiopathic scoliosis patients to describe their perception of their deformity. In a previous stduy, the scale has shown good correlation with magnitude of the curve METHODS: The study included 70 patients (60 women and 10 men), mean age 19.4 years (range 12–40), with idiopathic scoliosis. Each patient filled out the WRVAS and the SRS-22 questionnaire. Thoracic and lumbar curve angles were determined in standing X-rays and the largest was named Cobbmax. WRVAS internal consistency was assessed with Cronbach's alpha. Correlation coefficients were calculated between Cobbmax and the various WRVAS questions, and Cobbmax and the SRS-22 scales. The correlation between the WRVAS and SRS-22 was also determined RESULTS: Mean magnitudes were thoracic curve, 36.6° and lumbar curve, 33.2°; average Cobbmax was 37.9°. The mean total WRVAS score was 15.6. Mean scores for the various SRS-22 scales were function 4.6, pain 4.3, self-image 3.7, mental health 4.2, and total score 84.1. Internal consistency for the WRVAS was excellent (Cronbach's alpha, 0.9), and there were no signs of collinearity among the seven questions (tolerance range 0.2–0.5). All the items on the WRVAS correlated significantly with Cobbmax (correlation coefficients, 0.4 to 0.7). The correlation between the total WRVAS and total SRS-22 score was -0.54 (P = .0001) and between WRVAS total score and SRS-22 image domain score was -0.57 (p = 0.0001) CONCLUSION: The WRVAS showed excellent internal consistency and absence of collinearity. There was a highly significant correlation between the results of the test and the magnitude of the deformity. The WRVAS correlated significantly with the SRS-22 image scale. The WRVAS is a valid instrument to assess scoliosis patients perception of their deformit