Biomatériaux et cage de fusion cervicale (modélisation in vivo et applications cliniques)

Les interventions de Cloward et Smith-Robinson constituent les interventions de référence dans le traitement des névralgies cervico-brachiales d'origine discale et ostéophytiques. Elles sont grevées d'une morbidité liée d'une part aux défauts mécaniques du greffon osseux autologue et d'autre part à la prise de greffe iliaque. Les cages intersomatiques cervicales constituent une alternative à ces interventions et ont pour but d'améliorer le résultat mécanique (hauteur discale, lordose locale) et de diminuer la morbidité liée à la prise de greffe. La première partie de ce travail a évalué et validé sur modèle animal une cage en PEEK impactée associée à de l'os autologue et deux types de biomatériaux de substitution osseuse (céramiques biphasées : MBCP et MBCP gel). Cette étude a également validé la microtomographie comme technique d'imagerie capable d'évaluer la fusion osseuse et l'intégration d'un substitut osseux. La seconde partie expose les résultats d'une étude clinique prospective, randomisée évaluant la même cage associée à de l'os autologue ou du MBCP. L'utilisation de la cage restitue la hauteur discale et obtient des taux de fusion de 90%. L'utilisation du MBCP diminue de façon significative la morbidité liée à la prise de greffe iliaque sans compromettre le résultat mécanique.Cloward and Smith Robinson operations are gold standards in cervical spondylosis surgery. However, these procedures are associated to mechanical failure of the graft and residual pain in the iliac crest. The use ofintersomatic cages is meant to avoid those problems. The first part of this work was to compare autologous bone graft, PEEK cages, and two types ofbio-ceramics, namely MBCP and MBCP gel, in an animal model. This study also validated microtomography as a reliable technique for assessing bony fusion and osteointegration. The second part of the work was to expose the results of a prospective randomized clinical study looking at PEEK cage, autologous bone graft and MBCP. The use of the cage restored disc height and achieved 90% fusion rate. The use of MBCP significantly reduced iliac crest- related morbidity without interfering with the mechanical result.NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUP (751062107) / SudocNANTES-Bib.Odontologie (441092219) / SudocSudocFranceF

Inconsistent relationship between body weight/body mass index prior to total knee arthroplasty and the 12-year survival

Background: The primary hypothesis was that body weight (BW) and body mass index (BMI) significantly impact the long-term survival rate after implantation of a mobile bearing total knee arthroplasty (TKA).Methods: A national, multicentric, retrospective study was performed in France. A total of 1604 TKAs were included. The 10-year follow-up was documented, and the influence of BW and BMI on the survival rate was assessed.Results: There was a significant influence of the BW on the 12-year survival rate for any reason and for infection; but this influence was not proportional to the BW or BM]. There was no significant influence of the BMI on the 12-year survival rate for any reason, for any mechanical reason or for infection.Conclusion: Our results suggest that a higher BMI should not be considered as a risk factor for revision for mechanical purpose if a mobile bearing TKA with confirming design is implanted. (C) 2019 Elsevier B.V. All rights reserved

Watt-level diode-pumped thulium lasers around 2.3 µm

International audienc

Watt-level mid-infrared continuous-wave Tm:YAG laser operating on the 3H4 → 3H5 transition

International audienceWe report on the first continuous-wave mid-infrared Tm:Y3Al5O12 laser operating on the 3H4 → 3H5 transition. The 3.2 at.% Tm:Y3Al5O12 laser generated a maximum output power of 1.07 W at ~2.19 & 2.32 μm with a high slope efficiency of 46.3% (vs. the absorbed pump power) exceeding the Stokes limit. Depending on the output coupling and the pump power, a set of discrete laser lines in the range of 2.164–2.346 μm was observed. The spectroscopic properties of Tm:Y3Al5O12 relevant for the mid-infrared laser operation are revised. The maximum stimulated-emission cross-section for the 3H4 → 3H5 transition is 0.35 × 10−20 cm2 at 2324 nm and the emission bandwidth is ~37 nm. The overlap of the 3F4 → 3H6 and the 3H4 → 3H5 transitions is quantified revealing the formulas for Stokes and anti-Stokes phonon sidebands of emission bands. Tm:Y3Al5O12 is promising for broadly tunable (2.1–2.5 μm) and mode-locked mid-infrared oscillators

Acute Achilles Tendon Rupture: Ultrasonography and Endoscopy-Assisted Percutaneous Repair

To date, there is no consensus concerning the treatment of acute Achilles tendon ruptures. Although surgical treatment decreases the risk of a recurrent rupture, it is not without complications. In particular, percutaneous sutures may cause a lesion of the sural nerve. The purpose of this Technical Note is to describe a reliable and reproducible surgical procedure for treating these lesions. The first operative phase consists of an ultrasound detection that makes it possible to identify the tendon extremities and the sural nerve, which is necessary to secure the posterolateral arthroscopic tract as well as to perform the percutaneous suture. The entry point is thus centered on the lesion and placed at a distance from any surrounding nerve risk. The second arthroscopic phase makes it possible to release the tendon lesion, control the transtendon passage of the surgical threads, and evaluate the dynamic contact of the tendon edges. At the end of the intervention, the complete disappearance from the transillumination via the rupture also makes it possible to ensure the disappearance of the tendon gap. Achilles tendon percutaneous sutures after the ultrasound detection and under arthroscopic control thus makes it possible to control the contact of the tendon edges, while at the same time decreasing the risk of a lesion of the sural nerve, with minimal scarring

Use of morselized allografts for acetabular reconstruction during THA revision: French multicenter study of 508 cases with 8 years’ average follow-up

International audienceBackgroundIn the context of acetabular reconstruction, bone defects can be filled with processed or unprocessed bone allografts. Published data are often contradictory on this topic and few studies have been done comparing processed allografts to fresh-frozen ones. This led us to conduct a large study to measure the factors impacting the survival of THA revision: (1) type of allograft and cup, (2) technical factors or patient-related factors.HypothesisAcetabular reconstruction can be performed equally well with frozen or processed morselized allografts.Materials and methodsThis retrospective, multicenter study of acetabular reconstruction included 508 cases with a minimum follow-up of 5 years. The follow-up for the frozen grafts was shorter (7.86 years ± 1.89 [5–12.32]) than that of the processed grafts (8.22 years ± 1.77 [5.05–15.48]) (p = 0.029). However, the patients were younger at the time of the primary THA procedure in the frozen allograft group (51.5 years ± 14.2 [17–80]) than in the processed group (57.5 years ± 13.0 [12–94]) (p < 0.001) and were also younger at the time of THA revision (67.8 years ± 12.2 [36.9–89.3] versus 70 years ± 11.7 [25–94.5]) (p = 0.041).ResultsThere were more complications overall in the frozen allograft group (46/242 = 19.0%) than the processed allograft group (35/256 = 13.2%) (p = 0.044) with more instances of loosening in the frozen group (20/242 [8.2%]) than in the processed group (6/266 [3.3%])(p = 0.001). Conversely, the dislocation rate (16/242 = 6.6% vs. 17/266 = 6.4%) (p = 0.844) and infection rate (18/242 = 7.4% vs. 15/266 = 5.7%) (p = 0.264) did not differ between groups. The subgroup analysis reveal a correlation between the occurrence of a complication and higher body mass index (BMI) (p = 0.037) with a higher overall risk of complications in patients with a BMI above 30 or under 20 (p = 0.006) and a relative risk of 1.95 (95% CI: 1.26–2.93). Being overweight was associated with a higher risk of dislocation (relative risk of 2.46; 95% CI: 1.23–4.70) (p = 0.007). Loosening was more likely to occur in younger patients at the time of the procedure (relative risk of 2.77; 95% CI: 1.52–6.51) (p = 0.040) before 60 years during the revision. Lastly, patients who were less active preoperatively based on the Devane scale had an increased risk of dislocation (relative risk of 2.51; 95% CI: 1.26–8.26) (p = 0.022).DiscussionOur hypothesis was not confirmed. The groups were not comparable initially, which may explain the differences found since the larger number of loosening cases in the frozen allograft group can be attributed to group heterogeneity. Nevertheless, morselized allografts appear to be suitable for acetabular bone defect reconstruction. A randomized study would be needed to determine whether frozen or processed allografts are superior.Level of evidenceIII, comparative retrospective study