Predictability in Achieving Target Intervertebral Lordosis Using Personalized Interbody Implants.

BACKGROUND: Lumbar lordosis distribution has become a pivotal factor in re-establishing the foundational alignment of the lumbar spine. This can directly influence overall sagittal alignment, leading to improved long-term outcomes for patients. Despite the wide availability of hyperlordotic stock cages intended to achieve optimal postoperative alignment, there is a lack of correlation between the lordotic shape of a cage and the resultant intervertebral alignment. Recently, personalized spine surgery has witnessed significant advancements, including 3D-printed personalized interbody implants, which are customized to the surgeons treatment and alignment goals. This study evaluates the reliability of 3D-printed patient-specific interbody implants to achieve the planned postoperative intervertebral alignment. METHODS: This is a retrospective study of 217 patients with spinal deformity or degenerative conditions. Patients were included if they received 3D-printed personalized interbody implants. The desired intervertebral lordosis (IVL) angle was prescribed into the device design for each personalized interbody (IVL goal). Standing postoperative radiographs were measured, and the IVL offset was calculated as IVL achieved minus IVL goal. RESULTS: In this patient population, 365 personalized interbodies were implanted, including 145 anterior lumbar interbody fusions (ALIFs), 99 lateral lumbar interbody fusions (LLIFs), and 121 transforaminal lumbar interbody fusions. Among the 365 treated levels, IVL offset was 1.1° ± 4.4° (mean ± SD). IVL was achieved within 5° of the plan in 299 levels (81.9%). IVL offset depended on the approach of the lumbar interbody fusion and was achieved within 5° for 85.9% of LLIF, 82.6% of transforaminal lumbar interbody fusions and 78.6% of ALIFs. Ten levels (2.7%) missed the planned IVL by >10°. ALIF and LLIF levels in which the plan was missed by more than 5° tended to be overcorrected. CONCLUSIONS: This study supports the use of 3D-printed personalized interbody implants to achieve planned sagittal intervertebral alignment. CLINICAL RELEVANCE: Personalized interbody implants can consistently achieve IVL goals and potentially impact foundational lumbar alignment

Empirical investigation to explore potential gains from the amalgamation of Phase Changing Materials (PCMs) and wood shavings

The reduction of gained heat, heat peak shifting and the mitigation of air temperature fluctuations are some desirable properties that are sought after in any thermal insulation system. It cannot be overstated that these factors, in addition to others, govern the performance of such systems thus their effect on indoor ambient conditions. The effect of such systems extends also to Heating, Ventilation and Air-conditioning (HVAC) systems that are set up to operate optimally in certain conditions. Where literature shows that PCMs and natural materials such as wood-shavings can provide efficient passive insulation for buildings, it is evident that such approaches utilise methods that are of a degree of intricacy which requires specialist knowledge and complex techniques, such as micro-encapsulation for instance. With technical and economic aspects in mind, an amalgam of PCM and wood-shavings has been created for the purpose of being utilised as a feasible thermal insulation. The amalgamation was performed in the simplest of methods, through submerging the wood shavings in PCM. An experimental procedure was devised to test the thermal performance of the amalgam and compare this to the performance of the same un-amalgamated materials. Comparative analysis revealed that no significant thermal gains would be expected from such amalgamation. However, significant reduction in the total weight of the insulation system would be achieved that, in this case, shown to be up to 20.94%. Thus, further reducing possible strains on structural elements due to the application of insulation on buildings. This can be especially beneficial in vernacular architectural approaches where considerably large amounts and thicknesses of insulations are used. In addition, cost reduction could be attained as wood shavings are significantly cheaper compared to the cost of PCMs

From the imprints of French poetry to the expression of committed Persian poetry : the case of Ahmad Shâmlou and Nimâ Yushidj

Dans cette thèse de littérature comparée, plus qu’une histoire politique des poètes Nimâ Yushidj et Ahmad Shâmlou, nous avons cherché à comprendre comment ceux-ci négocient les rapports entre champ politique et champ poétique. Alors que la modernité consiste, selon Baudelaire, à « dépolitiser » les auteurs, l'engagement de la poésie persane est pourtant l’un des enjeux de la littérature moderne en Iran. Comment peut-on trouver des expressions alternatives pour définir cette étrange alliance entre poésie et politique ? Nimâ Yushidj (1895- 1960) et Ahmad Shâmlou (1925-2000) sont deux poètes les plus lus et les figures poétiques les plus marquantes de la littérature persane moderne. Dans la foulée de la Révolution constitutionnelle persane (ou la période dite Mashroutiat) en 1905, ils ont contribué à libérer leur expression poétique par un style raffiné et conforme à leur temps. En prenant des images puisées dans la poésie française, ils ont conçu une particularité poétique sur le modèle français, mais dans le contexte de leur société. Ils ont créé ainsi une hybridation littéraire et identitaire qui confronte les vestiges d'un traditionalisme à la modernité. Comment peut-on traiter une littérature sans être absent du débat et sans entrer en contact avec l'Histoire et l'actualité ? Pourquoi la question de l'engagement a-t-elle si explicitement été poursuivie par ces deux poètes persans du XXe siècle ? Comment rendre au fait littéraire, en principe affranchi du politique et de ses contraintes, son autonomie et sa spécificité ? Cette thèse cherche à répondre à ces différentes questions.In this comparative literature thesis, rather than a political history of the poets Nimâ Yushidj and Ahmad Shâmlou, we have sought to understand how they negotiate the relationship between political and poetic fields. While modernity consists, according to Baudelaire, in "depoliticizing" authors, the commitment of Persian poetry is nevertheless one of the issues of modern literature in Iran. How can we find alternative expressions to define this strange alliance between poetry and politics? Nimâ Yushidj (1895- 1960) and Ahmad Shâmlou (1925-2000) are two of the most widely read poets and the most prominent poetic figures in modern Persian literature. In the wake of the Persian Constitutional Revolution (or the so-called Mashroutiat period) in 1905, they contributed to the liberation of their poetic expression through a refined style in keeping with their time. By taking images from French poetry, they designed a poetic particularity on the French model, but in the context of their society. In this way, they created a literary and identity hybridization that confronts the vestiges of traditionalism with modernity. How can one deal with literature without being absent from the debate and without coming into contact with history and current events? Why has the question of commitment been so explicitly pursued by these two twentieth-century Persian poets? How can we give back to the literary fact, in principle freed from politics and its constraints, its autonomy and its specificity? This thesis seeks to answer these different questions. In this thesis of comparative literature, more than a political history of the poets Nima Yushidj and Ahmad Shâmlou, we sought to understand how they negotiate the relations between the political field and the poetic field. While modernity consists, according to Baudelaire, in «depoliticizing» the authors, the commitment of Persian poetry is nevertheless one of the stakes of modern literature in Iran. How can we find alternative expressions to define this strange alliance between poetry and politics? Nimâ Yushidj (1895-1960) and Ahmad Shâmlou (1925-2000) are two of the most widely read poets and poetic figures in modern Persian literature. In the wake of the Persian Constitutional Revolution (or the so-called Mashroutiat period) in 1905, they helped to liberate their poetic expression by a refined style in keeping with their time. By taking images drawn from French poetry, they have conceived a poetic peculiarity on the French model, but in the context of their society. They have thus created a literary and identity hybridization that confronts the vestiges of traditionalism with modernity. How can a literature be treated without being absent from the debate and without coming into contact with history and current events? Why was the question of commitment so explicitly pursued by these two 20th century Persian poets? How can we return to the literary fact, in principle free from politics and its constraints, its autonomy and its specificity? This thesis seeks to answer these different questions