Section Of Tendon Research Articles

Temporal and spatial expression of TGF-β1 in an Achilles tendon section model after application of platelet-rich plasma

To investigate the effect of platelet-rich plasma (PRP) on TGF-beta1 expression during tendon healing. We used 48 skeletally mature New Zealand White rabbits. 24 rabbits received the PRP, and 24 rabbits served as an untreated control group. Equal numbers of animals were sacrificed at 1st, 2nd, 3rd, and 4th week. The surgical procedure involved a transverse incision to transect the Achilles tendon. A volume of 1ml of PRP was then injected into the tendon mass in the PRP group. Histological and immunohistochemical evaluations with an anti-TGF-beta primary antibody were performed. The pattern of expression of TGF-beta1 in the PRP group was characterized by a significant upregulation during the first 2 weeks and subsequently significant downregulation in the 3rd and 4th week in comparison with the controls. Our results suggest that PRP may affect the tendon healing process by altering the expression of TGF-beta1.

Systemic Proteoglycan Deposition Is Not a Characteristic of Equine Degenerative Suspensory Ligament Desmitis (DSLD)

Recently Degenerative Suspensory Ligament Desmitis (DSLD) has been proposed to be a disease characterized by systemic deposition of proteoglycan (PG) in connective tissues. To investigate this hypothesis, 6 clinically affected Peruvian Paso horses were compared to 2 unaffected quarterhorses and one unaffected standardbred. Histological sections of limb ligaments and tendons, nuchal ligaments, aortas, hearts, eyes, visceral organs and brains from both groups were stained with H&E as well as special stains for PG. Safranin-O stained sections were found to be optimal for elucidating the presence of PG. Although lesions characteristic of DSLD were present in suspensory ligaments of each clinically affected horse, including foci of chondroid metaplasia with abundant PG, a similar but less pronounced pattern of PG deposition was present in control horses. In contrast to findings of the previous study, PG deposition was not unique to DSLD horses, and PG deposition in aortas and nuchal ligaments of some control horses exceeded levels of PG present in similar tissue of DSLD horses. Furthermore, the “vascular lesion” described in the media of arteries as cellular separation and intercellular amorphous matrix deposition was within the spectrum of changes recognized in both affected and unaffected horses. We found no evidence that DSLD is a systemic PG deposition disease.

Organization of collagen bundles during tendon healing in rats treated with L-NAME

The Achilles tendon can support high tension forces and may experience lesions. The damaged tissue does not regenerate completely, with the organization and mechanical properties of the repaired tendon being inferior to those of a healthy tendon. Nitric oxide (NO) plays an important role in wound repair. We have examined the structural reorganization and repair in Achilles tendon after injury in rats treated with the NO synthase inhibitor L-NAME. The right Achilles tendon of male Wistar rats was partially transected. One group of rats was treated with L-NAME (~300 mg/kg per day, given in drinking water) for 4 days prior to tendon sectioning and throughout the post-operative period. Control rats received water without L-NAME. The tendons were excised at 7, 14, and 21 days post-injury and used to quantify hydroxyproline and for mechanical tests. Tendons were also processed for histomorphological analysis by polarized light microscopy, which showed that the collagen fibers were disorganized by day 7 in non-treated and L-NAME-treated rats. In non-treated rats, the organization of the extracellular matrix was more homogeneous by days 14 and 21 compared with day 7, although this homogeneity was less than that in normal tendon. In contrast, in injured tendons from L-NAME-treated rats, the collagen fibers were still disorganized on day 21. Tendons from treated rats had more hydroxyproline but lower mechanical properties compared with those from non-treated rats. Thus, NO modulates tendon healing, with a reduction in NO biosynthesis delaying reorganization of the extracellular matrix, especially collagen.

Treadmill running exercise results in the presence of numerous myofibroblasts in mouse patellar tendons

Mechanical loading is known to alter tendon structure, but its cellular mechanisms are unclear. This study aimed to determine the effect of mechanical loading on tendon cells in vivo. C57BL/6J female mice were used in a treadmill running study. The treadmill running protocol consisted of treadmill training for 1 week, followed by sustained moderate running at 13 m/min for 50 min/day, 5 days/week, for 3 weeks. Immunohistochemical staining of tendon sections of mice after treadmill running revealed that numerous cells in the tendon section expressed alpha-SMA, whereas in the tendon sections of control mice, only a few cells exhibited weak alpha-SMA signals. Furthermore, mouse patellar tendon cells (MPTCs) derived from treadmill running mice were generally larger in culture, proliferated faster, expressed a higher level of alpha-SMA, and formed more abundant stress fibers compared to MPTCs from control mice. In addition, MPTCs from treadmill running mice generated larger traction forces (169 +/- 66.1 Pa) than those from control mice (102 +/- 34.2 Pa). Finally, cells from treadmill running mice produced higher levels of total collagen (516.4 +/- 92.7 microg/10,000 cells) than their counterparts (303.9 +/- 34.8 microg/10,000 cells). Thus, mechanical loading via treadmill running increased the presence of myofibroblasts in mouse patellar tendons. As myofibroblasts are activated fibroblasts, their presence in the tendon following treadmill running indicates that they actively repair and remodel tendon tissue under strenuous mechanical loading, leading to known changes in tendon structure.

Efficiency and distribution of gene delivery to the injured tendons by microinjection and tissue re-actions caused by vectors

Objective To investigate efficiency and distribution of gene delivery to the injured tendons by microinjeetion and tissue reactions caused by different vectors. Methods By using a mi-croinjection technique, 10μl of pCMV-EGFP, pCAGGS-EGFP, AAV2-EGFP and Ad5-EGFP harboring enhanced green fluorescence protein (EGFP) gene were respectively injected to two sites of the proximal stump of 48 transected digital flexor tendons in 18 chickens. At days 3, 7, 14 and 21, the tendons wereharvested for observing distribution and expression of EGFP under a fluorescence microscope by using fro-zen tissue sections. The tendon sections were also stained with hematoxylin and eosin to examine inflam-mation caused by these vectors. The other 24 normal flexor tendons were served as controls. ResultsCompared with normal tendon tissues, the EGFP expression was observed in tendons at days 3, 7, 14 and21 after injection. The EGFP expression was observed at day 3 and reached peak at day 7 for all vectors.The EGFP expression was decreased at day 14 but seldom seen at day 21. EGFP was distributed evenly inthe injected tendon segment adjacent to the cut level. The EGFP expression in the tendons injected withAAV2-EGFP and Ad5-EGFP was higher than that with pCMV-EGFP and pCAGGS-EGFP injection, withinsignificant statistical difference upon the EGFP expression between AAV2-EGFP and Ads-EGFP vec-tors. Tissue reactions of the tendons caused by the liposome-plasmid vector ( including pCMV-EGFP and pCAGGS-EGFP) were the most prominent among all vectors. Infiltration of inflammatory cells, chiefly lymphocytes and neutrophilic granulocytes, were found. The tendons injected with AAV2 vectors presen-ted gentle inflammatory reactions. Conclusions Mieroinjection to two sites of each tendon stump deliv-ers the transgene to the entire tendon segment adjacent to the cut. Gene delivery by the AAV2 and Ad5 vectors has the highest cfficiency among four vectors tested, when expression level peaks at day 7 after in-jection and AAV2 vector causes the slightest tissue reactions in the tendons, indicating that the AAV2 vector is a promising gene delivery vector and microinjection is practical for tendon gene therapy. Key words: Tendon injuries; Gene therapy ; Vector

Apoptotic Cells and the Histopathologic Findings in Rotator Cuff Tears

Purpose: We analyzed the relationship between the size of the torn rotator cuff and the frequency of finding apoptotic cells (apoptotic index) or pathological degeneration in the rotator cuff. Materials and Methods: The edges of torn supraspinatus tendons were obtained from patients with rotator cuff tear (n=63). The study group consisted of 2 small, 22 medium, 22 large and 17 massive tears. For the histopathologic evaluation, the H&E stained sections of the torn supraspinatus tendons were examined. Apoptosis was detected with TUNEL assay. We analyzed the relationships between the tear size and the pathologic findings or the apoptotic index. Results: Significant differences could not be found for the fibroblast cellularity, thickening of the synovial lining and proliferation of blood vessels according to the size of the rotator cuff tear. All the specimens had apoptotic cells that were concentrated around the margin of the tear site. The apoptotic indexes according to the tear size were 58.50 for the small tears, 27.25 for the medium tears, 33.29 for the large tears and 31.96 for the massive tears. No significant correlation was found between the tear size and the apoptotic index. Conclusion: There were no significant differences in the apoptotic indices, the fibroblast cellularity, the thickening of the synovial lining and the proliferation of blood vessels according to the size of the rotator cuff tear, and there were no correlations between the apoptotic index and the histopathologic findings.

Modeling optical behavior of birefringent biological tissues for evaluation of quantitative polarized light microscopy

Quantitative polarized light microscopy (qPLM) is a popular tool for the investigation of birefringent architectures in biological tissues. Collagen, the most abundant protein in mammals, is such a birefringent material. Interpretation of results of qPLM in terms of collagen network architecture and anisotropy is challenging, because different collagen networks may yield equal qPLM results. We created a model and used the linear optical behavior of collagen to construct a Jones or Mueller matrix for a histological cartilage section in an optical qPLM train. Histological sections of tendon were used to validate the basic assumption of the model. Results show that information on collagen densities is needed for the interpretation of qPLM results in terms of collagen anisotropy. A parameter that is independent of the optical system and that measures collagen fiber anisotropy is introduced, and its physical interpretation is discussed. With our results, we can quantify which part of different qPLM results is due to differences in collagen densities and which part is due to changes in the collagen network. Because collagen fiber orientation and anisotropy are important for tissue function, these results can improve the biological and medical relevance of qPLM results.

Mini-invasive approach and navigation in total prosthesis of the hip

The anterior approach to the hip, initially described by Hueter, has been modified and used by Jean and Robert Judet since 1947 for fixing an acrylic prosthesis [1,2]. In 1993, Marc Siguier rendered this approach completely mini-invasive by avoiding any muscular desinsertion or sectioning of tendons [3]. When we learnt about the possibilities of using the navigation technique for a hip prosthesis using the Orthopilot system, we decided to combine these two innovations so as to induce a minimum of aggression and a maximum of security while fixing a hip prosthesis. A study carried out on the positioning of the acetabulum, with or without navigation, as well as a comparison between two navigation systems are mentioned in an attempt to validate the relevance of the frame of references.

Fourier-transform infrared anisotropy in cross and parallel sections of tendon and articular cartilage

BackgroundFourier Transform Infrared Imaging (FTIRI) is used to investigate the amide anisotropies at different surfaces of a three-dimensional cartilage or tendon block. With the change in the polarization state of the incident infrared light, the resulting anisotropic behavior of the tissue structure is described here.MethodsThin sections (6 μm thick) were obtained from three different surfaces of the canine tissue blocks and imaged at 6.25 μm pixel resolution. For each section, infrared imaging experiments were repeated thirteen times with the identical parameters except a 15° increment of the analyzer's angle in the 0° – 180° angular space. The anisotropies of amide I and amide II components were studied in order to probe the orientation of the collagen fibrils at different tissue surfaces.ResultsFor tendon, the anisotropy of amide I and amide II components in parallel sections is comparable to that of regular sections; and tendon's cross sections show distinct, but weak anisotropic behavior for both the amide components. For articular cartilage, parallel sections in the superficial zone have the expected infrared anisotropy that is consistent with that of regular sections. The parallel sections in the radial zone, however, have a nearly isotropic amide II absorption and a distinct amide I anisotropy.ConclusionFrom the inconsistency in amide anisotropy between superficial to radial zone in parallel section results, a schematic model is used to explain the origins of these amide anisotropies in cartilage and tendon.

Optical anisotropy of collagen fibers of rat calcaneal tendons: An approach to spatially resolved supramolecular organization

Optical anisotropic characteristics investigated by polarization microscopy have been valuable for the study of the oriented organization of collagen fibers in tendons. However, topographic differences in supramolecular organization of collagen fibers along extensive areas in tendons have not yet been described. Here, the statistical variability of the oriented organization of collagen fibers along extensive areas (10(5)-10(6)microm(2)) of 7-microm thick unstained sections of rat calcaneal tendons were studied by assessing their birefringence with polarization microscopy and image analysis, and the periodic frequency distribution in their birefringent images with the fast Fourier transform (FFT). Various levels of birefringence intensity were determined principally by image analysis procedures, and periodicity in the birefringent images was revealed by FFT line profile and spectrum image patterns. Present results support the idea of a helical distribution for collagen bundles along the tendon long axis, and of a statistical architecture for the rat calcaneal tendons in terms of variability in the oriented distribution of their collagen fibers.

Immunolocalisation and expression of keratocan in tendon

Short Communication Immunolocalisation and expression of keratocan in tendon S. G. Rees Ph.D.y*, A. D. Waggett Ph.D.z, B. C. Kerr Ph.D.z, J. Probert B.Sc.z, E. C. Gealy Ph.D.z, C. M. Dent M.D.x, B. Caterson Ph.D.z and C. E. Hughes Ph.D.z ySchool of Medicine, Swansea University, Singleton Park, Swansea, SA2 8PP, UK zConnective Tissue Biology Laboratories, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3US, UK xSchool of Medicine, Department of Orthopaedic and Trauma Surgery, Cardiff University, Llandough Hospital, Penlan Road, Penarth, Vale of Glamorgan, CF64 2XX, UK

The Primary Cilium of Connective Tissue Cells: Imaging by Multiphoton Microscopy

Although the role of the primary cilium as a sensory organelle in epithelial cells has been elucidated significantly over the past decade, the function of primary cilia in connective tissue cells has been studied less extensively. Primary cilia have been implicated as mechanotransducers in connective tissues, but the mechanisms by which the cells sense loads and convert them to biochemical signals for tissue formation and adaptation are poorly understood. Before hypotheses regarding the function of the primary cilium in connective tissue cells can be tested, methods for quantitation of incidence as well as three-dimensional visualization of primary cilia with respect to the extracellular matrix (ECM) are needed. The objective of this study was to develop a rapid method for visualizing primary cilia in their native ECM in a wide range of connective tissues. Whole-mount immunohistochemical and multiphoton microscopy techniques were developed to simultaneously image primary cilia, cell nuclei, and collagen and their relationships to each other in situ. Axonemes of primary cilia projecting into the ECM were successfully visualized in thick sections of growth plate cartilage, tendon, ligament, meniscus, intervertebral disc, and perichondrium. These methodologies will allow analysis of the incidence and three-dimensional orientation of primary cilia and enable investigation of the role of primary cilia in normal and pathological growth and adaptation in a variety of musculoskeletal tissues.

The accumulation of inflammatory cells in synovial sheath and epitenon during adhesion formation in healing rat flexor tendons.

The accumulation of inflammatory cells in synovial tissue was studied using indirect immunofluorescence assays on cell cultures and frozen tissue sections of healing rat digital flexor tendons. Flexor tendons were collected from rats 3, 7 and 14 days after crush injury. Tendon sheath and epithenon cells were isolated by sequential enzymic digestion and cultured for 2 days. Subpopulations of synovial and inflammatory cells were identified with MoAbs against cell surface glycoproteins present on B lymphocytes (CD45), T lymphocytes (CD2, CD4, CD8), macrophages (CD14) and endothelial cells. A phagocytosis assay was also used to identify macrophages. We report a substantial increase in the number of T lymphocytes (mainly helper/inducer) and phagocytotic cells with monocyte/macrophage surface markers in tendon sheath and epitenon 3 days after crush injury. The infiltration of inflammatory cells into synovial sheath and epitenon preceded an increase in fibronectin production by tendon cells which was seen 7 days after injury. To study the interaction between T lymphocytes and synovial cells in vitro, we established synovial fibroblast-like type B cell cultures and used stimulated and non-stimulated T lymphocytes in cell binding assays. We observed increased adhesiveness between unstimulated synovial cells and synovial cells previously cultured with activated and non-activated T lymphocytes. ELISA inhibition studies have shown an increase in fibronectin production by synovial fibroblasts co-cultured with stimulated CD4+ T lymphocytes. We suggest that the presence of inflammatory cells in synovial sheath and epitenon during tendon healing induces synovial fibroblasts and epitenon cells to increase their production of fibronectin, which provides a scaffold for subsequent adhesion formation.

The Achilles Tendon Insertion is Crescent-shaped: An In Vitro Anatomic Investigation

Anatomic and operative textbooks and current literature do not clearly describe the Achilles tendon interface to the calcaneal tuberosity. We dissected 51 specimens to identify the detailed anatomy of the Achilles tendon insertion. Achilles tendon fascicles expanded from the anterior aspect of the distal Achilles tendon over the retrocalcaneal bursa to the anterior part of the Haglund's tuberosity in nearly half of the specimens. The insertion of the transverse section of the Achilles tendon regularly had a crescent-shape corresponding to the posterior calcaneal prominence. In transverse sections, all specimens had a curved appearance with a radius of curvature ranging from 13.8 mm to 43.6 mm (mean, 20.4 mm) and Achilles tendon extensions to the lateral and medial calcaneal surfaces reached 1.0 mm (mean) and 3.5 mm (mean) anterior in relation to the most posterior point of the calcaneal tuberosity. Knowledge of the arcuate configuration and of the medial and lateral extensions of the plantaris and the Achilles tendon insertion with respect to the transverse plane is important to avoid iatrogenic complications during resection of Haglund's tuberosity.

Langfristige Beobachtung von 166 operierten Patienten mit angeborener Hüftverrenkung

166 patients with congenital dislocation of the hip, ranging from 10 months to 5 years old, were operated between 1958 and 1971. 140 patients were women (84%) and 26 patients were men (16%). 96 patients had unilateral and 70 patients had bilateral dislocation; that makes a total of 236 dislocated hips. 61 patients with bilateral hip dislocation were operated simultaneously on both hips. All the patients were treated with adductor tenotomy and open reduction through Smith Petersen incision with section or elongation of the psoas tendon. The postoperative immobilization consisted in a period of one month pelvic toecast followed by 2 plaster casts with abduction rod during 3 to 5 months. The postoperatory follow-up ranged from 9 years to 26 years, 2 months; average 14 years, 5 months. The clinical evaluation comprises pain, hip mobility, gait and muscle power. excellent 138 (59%); good 66 (28%); fair 29 (12%); and poor 3 (1%). The radiological evaluation considered: Mose; acetabular femoral head index; Wiberg's CD-angle; cervico-diaphysiary angle and radial quotient. normal 5 (2%); excellent 44 (19%); good 78 (33%); subtotal 54%; fair 90 (38%), and poor 19 (8%). Complications (hips); infections 12 (5%); 3 of them deep ones (1%); residual subluxation 19 (8%); reluxation 1 (0.5%). Isquemic necrosis Grade II of Tönnis 31 (13%); Grade III 2 (1%) and Grade IV 1 (0.5%).

Reliability-based design criterion for TLP tendons

This paper presents a methodology to perform a Load and Resistance Factor Design (LRFD) criterion for the design of Tension Leg Platform (TLP) tendons in their intact condition. The proposed design criterion considers the Ultimate Limit State (ULS) for the tendon sections, expressed in terms of the expected value of the extreme Interaction Ratio (IR), considering long-term storm sea states, and takes into account the dynamic load effects interaction and the statistics of its associated extreme response. The partial safety factors are calibrated through a long-term reliability-based methodology for the storm environmental conditions in deep waters of the Campeche Bay, Mexico. Different target reliability values are considered in order to evaluate the effect of this key parameter on safety factors. The results show that the partial safety factors reflect both the uncertainty content and the importance of the random variables in structural reliability analysis. When tendons are designed according to the developed LRFD criterion, a less scattered variation of reliability indexes is obtained for different tendon sections across a single or a variety of TLP designs. Finally, it is observed that the target reliability value has a strong influence over the safety factor values and thus over the final size of the structural elements.

Étude comparative de deux techniques de section du tendon du muscle subscapulaire dans l’opération de Latarjet

The aim of this work was to compare the anatomic and functional effect on the subscapularis muscle of two ways of sectioning its tendon during Latarjet procedure: complete vertical section and Weaver section (partial section of the lower third preserving the upper part of the tendon). We compared two series (eight-year interval) of patients comparable for age, gender, form of instability, type and level of sports activity. Twenty-nine patients underwent complete vertical section (group 1) and 30 Weaver section (group 2). All were reviewed with minimum four year follow-up. The clinical analysis involved strength of internal rotation, the maximal hand-back distance, and the Constant and Duplay scores. The radiographic analysis was coupled with computed tomography in 46 patients (23 in each group). Loss of subscapularis muscle thickness compared with the non-operated side was noted as was the Bernageau fatty infiltration stage. No recurrent dislocation was noted in either group. There were six cases of nonynion in group 1 and seven in group 2. The Gerber was positive in five patients in group 1 and zero in group 2 (P=0.01). Loss of internal rotation strength between the operated and healthy side, expressed in percentage, was 48.4% for group 1 and 17.9% for group 2 (P<0.0006). In group 1, the fatty infiltration stage of the subscapularis muscle was: stage 0 (n=3), stage 1 (n=11), stage 2 (n=3), stages 3 and 4 (n=6). In group 2, these stages were: stage 0 (n=21), stage 1 (n=1), stage 1 (n=2) and zero stage 3 and 4 (P<0.0001). The Latarjet operation remains the reference procedure for anterior stabilization of the shoulder joint. The choice of the incision technique for the subscapularis muscle tendon remains a subject of debate. Recent studies have demonstrated the importance of subscapularis muscle trophicity to obtain a good mid- and long-term clinical outcome. We have ourselves demonstrated elsewhere that complete section of the subscapularis tendon leads to secondary tears and subsequent fatty degeneration. Our study demonstrates that Weaver section in the Latarjet procedure enables placing the bone block in conditions equivalent to those achieved with total section while preserving better trophicity of the subscapularis muscle.

Experimental Investigations of Anisotropic Shear Properties of Rabbit Patellar Tendons

Understanding the origins of the multiaxial material properties of soft tissues is crucial for quantifying the tissue material properties that govern the material behavior for accurate predictive modeling of biological systems. The purpose of this study is to quantify the shear material properties of the rabbit patellar tendon. These properties will be examined under different shear strain rates along the fiber direction and perpendicular to the fiber direction. Thin sections of patellar tendon were resected from mature male white New Zealand rabbits and were mounted on a custom-designed testing device, quickly followed by application of predetermined simple shear strains under physiological conditions. The tendons were sequentially sheared to 40% strain at strain rates of 0.1%, 1%, and 10% strain s-1 using a device driven by a computer-controlled stepper motor. The results suggest that the tendon exhibits direction-dependent viscoelastic shear properties, reflecting the structural anisotropy. These results can be used to generate stress state dependent constitutive models.

The anisotropic compressive mechanical properties of the rabbit patellar tendon

In this study, we examine the transverse and longitudinal compressive mechanical behavior of the rabbit patellar tendon. The anisotropic compressive properties are of interest, because compression occurs where the tendon attaches to bone and where the tendon wraps around bone leading to the development of fibro-cartilaginous matrices. We quantified the time dependent viscoelastic and anisotropic behavior of the tendon under compression. For both orientations, sections of patellar tendon were drawn from mature male white New Zealand rabbits in preparation for testing. The tendons were sequentially compressed to 40% strain at strain rates of 0.1, 1 and 10% strain(s) using a computer-controlled stepper motor driven device under physiological conditions. Following monotonic loading, the tendons were subjected to stress relaxation. The tendon equilibrium compressive modulus was quantified to be 19.49+/-11.46 kPa for the transverse direction and 1.11+/-0.57 kPa for the longitudinal direction. The compressive modulus at applied strain rates of 0.1, 1 and 10% strain(s) in the transverse orientation were 13.48+/-2.31, 18.24+/-4.58 and 20.90+/-8.60 kPa, respectively. The compressive modulus at applied strain rates of 0.1, 1 and 10% strain/s in the longitudinal orientation were 0.19+/-0.11, 1.27+/-1.38 and 3.26+/-3.49 kPa, respectively. The modulus values were almost significantly different for the examination of the effect of orientation on the equilibrium modulus (p=0.054). Monotonic loading of the tendon showed visual differences of the strain rate dependency; however, no significant difference was shown in the statistical analysis of the effect of strain rate on compressive modulus. The statistical analysis of the effect of orientation on compressive modulus showed a significant difference. The difference shown in the orientation analysis validated the anisotropic nature of the tendon.

External dacryocystorhinostomy

Abstract Purpose: Indications, techniques and complications of external DCR. Methods: Indications are lacrimonasal stenosis with clinical symptoms : epiphora, dacryocystitis . The external approach is more specifically interesting in case of canalicular stenosis associated, when a skin approach is necessary or in case of lacrimal tumor . The endonasal approach is the best way in case of nasal or sinusal pathology, failure of DCR or lacrimal abscess and for us in case of bilateral DCR. Technique is always the same, under general or local anaesthesia with nasal vasoconstriction. After disinfection, probing, the skin incision is short and rectilinear inside or outside the angular vessels. Marking is the anterior lacrimal crest. After section of the medial canthal tendon, an osteotomy is performed ; it must be wide with or without anterior ethmoidectomy. We make two anterior mucosal flaps which are sutured and fixed at the periosteum. We do not use systematically a bicanalicular intubation ; we put an intubation in case of canalicular stenosis, or for a second DCR or in case of surgical difficulties. The main complications are haemorrhages, cribrosal plate fracture with cerebrospinal leakage, infection, pain and in a few case, a bad scar. Results: The results are good. Anatomical and functional success are found in 88 to 96%, for us 91.2% . The failures occur during the three first months. Conclusions: Conclusion: To compare internal or endonasal DCR, the advantages for the external way are cost, rapidity and usual practise. Endonasal DCR needs a lot of material, an apprenticeship and usually a scanner before the surgery and systematically a bicanalicular intubation. In conclusion, external DCR remains an easy technique, which is quick, with high success rate and few complications.