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At least 487 records · Page 27Linked to original sources
PubMed1998

Is preoperative tibial traction responsible for peroneal nerve palsy in patients with a fractured hip?

A study of 456 cervical hip fractures treated with internal fixation was performed to evaluate the incidence of paralysis of the peroneal nerve following hip-fracture treatment. There were no cases of peroneal nerve paralysis in a group of 206 patient treated with a dynamic hip screw without preoperative traction. There were 2 cases of peroneal nerve paralysis in a group of 250 patients treated with 3 parallel screws with preoperative skeletal traction via a tibia pin. This difference was not significant according to Fischer's test (two-tailed P value = 0.5036). We conclude that the incidence of paralysis of the peroneal nerve following hip-fracture treatment is low although preoperative skeletal traction with the injured leg positioned in a Böhler-Braun splint may contribute to this complication.

Aged↗
PubMed1998

[Traction on the orthopedic table and pudendal nerve injury. Importance of electrophysiologic examination].

PURPOSE OF THE STUDY: We performed a retrospective study about perioperative pudendal nerve palsy following fracture table tractions. MATERIAL: Six palsies were investigated. Mean age was 26 years. All of them presented sensitive and motor dysfunctions secondary to nerve compression following tractions on the fracture table. METHODS: All of them had complete electrophysiological recordings including perineal electromyogram, measurement of sacral roots latencies, sensory velocity of the dorsal nerve of the penis, somatosensory evoked potentials of the pudendal nerve and measurement of its terminal branches. RESULTS: Neurological symptoms were stereotyped associating sensory signs and sexual disorders, must of them being transient. Perineal electrophysiological examination always confirmed reality of pudendal nerve palsy. DISCUSSION: We discuss incidence, mechanism, etiology and prevention of this pudendal nerve palsy. CONCLUSION: Emergence of stereotyped perineal symptoms following orthopaedic surgery, especially after tractions on fracture table, must prevail on physicians to search for pudendal nerve palsy. Usual outcome is good in the six months following surgery, but definitive aftermath does occur. Perineal electrophysiological examination can confirm pudendal nerve palsy and give prognosis elements.

Adolescent↗
PubMed1998

Foveal cysts: a premacular hole condition associated with vitreous traction.

OBJECTIVE: To define the clinical findings, cause, and outcome of patients with foveal cysts due to vitreous traction. METHODS: Follow-up of 18 patients with foveal cysts and no posterior vitreous detachment (PVD). Changes were documented in visual acuity, the appearance of the fovea, or the development of a macular hole or PVD. We studied 8 eyes using the retinal thickness analyzer. RESULTS: On follow-up, 9 of 23 eyes did not develop a PVD and still had a foveal cyst; 8 of 23 developed a full-thickness macular hole; 4 of 23 developed a PVD with resolution of the cyst; and 2 eyes underwent vitrectomy for the cyst before a full-thickness hole developed. Analysis with the retinal thickness analyzer showed splitting within the middle retinal layers and in some cases unroofing or absent inner retinal layers in the center of the cyst. CONCLUSIONS: Foveal cysts are caused by vitreous traction. These eyes may remain stable, develop full-thickness holes, or develop a PVD with resolution of the cystic changes. A foveal cyst seems to be a common finding in patients with foveal traction from a variety of mechanisms.

Aged↗
PubMed1981

Posterior lip traction caused by intravitreal gas.

Traction on the posterior edge of a large tear may be an irreparable consequence of an intraocular gas tamponade used in the first instance to treat the tear. In two of three patients treated with octofluorocyclobutane (C4F8) and perfluoromethane (CF4), redetachment of a retinal tear occurred as a result of traction on the posterior edge of the tear when, prior to the operation, the posterior edge seemed to be free of any traction. With redetachment, a membrane became visible between the anterior and posterior lips of the tear. The membrane was probably posterior hyaloid augmented by cellular proliferation. The gas bubble, which had been intended to press the retina against the pigment epithelium, probably brought the detached posterior hyaloid into contact with the retina as well, and an adhesion between the hyaloid and retina formed.

Adult↗
PubMed1986

Intravitreous fibronectin and platelet-derived growth factor. New model for traction retinal detachment.

In proliferative vitreoretinopathy and trauma, traction retinal detachments result from cellular migration into the vitreous cavity with contractile membrane formation. Cleary and Ryan have established the efficacy of intravitreous injection of autologous blood in reproducing this pathologic process in the rabbit eye. It has previously been shown that two serum components, fibronectin and platelet-derived growth factor, stimulate cellular migration. We now show that contractile membranes and traction retinal detachments occur in 72% of rabbit eyes within three weeks following intravitreous injection of fibronectin and platelet-derived growth factor. These results provide a straightforward new model to study the development of intravitreous cellular membranes and traction retinal detachments.

Animals↗
PubMed1988

Vitrectomy for macular traction caused by incomplete vitreous separation.

Pars plana vitrectomy was performed in 16 eyes to release vitreomacular traction. All patients had a symptomatic preoperative decrease in visual acuity, most often to 20/200. Partial detachment of the posterior vitreous surface was associated with vitreoretinal attachment remaining in the area of the macula and sometimes to the optic nerve head. The posterior vitreous traction on the macula was released by tangential traction on the posterior vitreous surface, causing it to separate from the retina. The postoperative vision was the same or improved in each case. No operative complications occurred, but progressive nuclear sclerosis developed postoperatively in five of the 15 phakic eyes.

Aged↗
PubMed1996

Influence of adhesion and cytoskeletal integrity on fibroblast traction.

Cellular contractility plays an important role in cell morphogenesis and tissue pattern formation. In this context, we examined how the expression of cell traction depends on cell-to-substrate contacts and cytoskeletal organization. Qualitative observation of chick fibroblasts cultured on an elastic film of polydimethylsiloxane indicated a strong spatial relationship between wrinkle pattern and distribution of actin stress fibers and focal contacts. In order to further characterize cell contractility, the projected area of Triton-permeabilized fibroblasts upon ATP-induced retraction was measured in various conditions of substrate adhesivity, cytoskeletal perturbation, and temperature. In all conditions, the relationship between degree of cell retraction and ATP concentration was well described by the laws of enzyme kinetics. Culturing cells on a gelatin-coated substrate, decreasing the temperature, using phosphate ribonucleotides other than ATP, and treating cells with cytochalasin D all diminished the rate of cell retraction, indicating that fibroblast traction is generated by a temperature- and ATP-dependent actin/myosin stress fiber sliding mechanism, transmitted to the substrate through focal adhesions. Treatment of cells with either nocodazole or taxol did not affect retraction of permeabilized fibroblasts upon stimulation with ATP, suggesting that microtubules do not directly resist cell traction. Treatment of cells with vanadate increased cell retraction, suggesting that intermediate filaments help transmit tension.

Adenosine Triphosphate↗
PubMed1991

Experimental traction retinal detachment in the cat.

We developed a reproducible model of traction retinal detachment (TRD) in the cat eye by creating a serous retinal detachment and then injecting 2.5 x 10(5) kitten dermal fibroblasts into the vitreous cavity at the site of a retinal wound. Serous detachments were produced by exposing an area of retina to focused light after intravenous injection of rose bengal (a photosensitizing dye). TRD developed rapidly within the first 2 weeks after fibroblast injection, accompanied by the formation of vitreoretinal strands and, to a lesser degree, epiretinal and/or subretinal proliferation. Histopathology demonstrated fibroblasts within the vitreous or along the posterior hyaloid face. Focal deposits of fibroblasts were occasionally found on the inner surface of the retina and/or in the subretinal space. Fibroblast proliferation was confirmed by uptake of radiolabeled thymidine. Deposition of collagen was noted at as early as 3 days after fibroblast injection. Neovascularization was not observed. Control eyes that did not receive fibroblasts showed resolution of serous detachment without retinal traction. In all eyes, retinal degeneration and thinning were seen in the area of previous photodynamic treatment. In this model of TRD, anteroposterior traction (due to vitreous strands) predominates, as is observed in experimental posterior penetrating ocular injury induced by intravitreal blood injection, which also results in vitreous strand formation. Our model, however, enables clinical assessment of TRD in the cat without the media opacification produced by vitreous blood.

Animals↗
PubMed1997

Vitrectomy for traction macular detachment in diabetic retinopathy.

BACKGROUND: A small number of eyes with proliferative diabetic retinopathy develop massive central fibrovascular membranes characterized by vitreoretinal tractions along the arcades and optic disk and retinal traction lines extending through the macula. The aim of our study was first to present the results of vitrectomy for removal of these central membranes and second to determine the correlation between preoperative parameters and postoperative visual outcome. SUBJECTS AND METHODS: We treated 28 eyes with severe central fibrovascular diabetic membranes by a modified bi-manual en bloc excision technique during vitrectomy. Preoperative examination included general status, visual acuity, slit-lamp investigation, binocular funduscopy, ultrasound investigation and visual evoked potentials (VEP). Further, we analyzed intraoperative complications and postoperative anatomic and functional outcomes. RESULTS: The retinas of 27 eyes with central traction retinal detachments were reattached by surgery. With a minimum of 6 months' follow-up, the macula remained attached in 24 eyes, while the retinas were completely attached in 22 eyes. Preoperative visual acuity was defective light perception to 0.1; an increase in visual acuity to maximal 0.1 was seen in 50% of the patients postoperatively. Preoperative visual acuity of light perception was associated with no functional improvement. Preoperative ultrasound investigation gave information about the real anatomic situation of the retina, especially if funduscopy was not possible. The other preoperative parameters could not predict correctly the functional outcome of vitrectomy in diabetics with severe central fibrovascular membranes because of the damage of the optic nerve and the retina. CONCLUSIONS: The high rate of anatomical reattachment after vitrectomy in diabetic eyes with severe central fibrovascular membranes is associated with a slight improvement of function; only preoperative visual acuity of hand motions or better was associated with an improvement of function.

Adult↗
PubMed1984

Unexpected traction retinal detachment: a complication of an animal model of pars plana vitrectomy.

We evaluated a rabbit model of the vitrectomized eye. In 16% of eyes the surgical procedure leads to the development of traction detachment of the vascularized portion of the retina (medullary ray). The traction originates in the vitreous base and is probably transmitted to the posterior retina via a sheet of detached vitreous cortex. In time course and morphology this differs from the experimental traction detachment seen after the injection of cells. Provided this complication is recognized, the vitrectomized rabbit eye is a useful and economic model for experimental studies.

Animals↗
PubMed2005

Increased nitric oxide (NO) pathway metabolites in the vitreous fluid of patients with rhegmatogenous retinal detachment or diabetic traction retinal detachment.

BACKGROUND: Nitric oxide (NO) plays a significant role in physiological and pathological processes in the retina. In the L-arginine-NO pathway, NO synthase (NOS) converts L-arginine to NO and L-citrulline. Increased NO production, mediated by inducible NOS has been implicated in the pathogenesis of various vitreoretinal diseases. In the present study it is hypothesized that in rhegmatogenous retinal detachment (RRD), the production of NO pathway metabolites might be upregulated. METHODS: Using high-pressure liquid chromatography citrulline, arginine and nitrite were measured in vitreous fluid of 93 eyes with RRD, nine eyes with a traction retinal detachment due to proliferative diabetic retinopathy (PDR), and in 49 control samples of vitreous fluid from eyes without retinal detachment. RESULTS: The mean vitreous concentrations of citrulline and arginine were significantly increased in eyes with RRD (9.6+/-4.3 and 97.3+/-29.2; respectively) or in eyes with a traction retinal detachment (25.8+/-10.3 and 130.7+/-23.7; respectively) as compared to control eyes (7.1+/-3.2 and 75.9+/-18.1; respectively). The mean level of nitrite was also higher in vitreous fluid of patients with RRD (2.24+/-1.4) or patients with a traction retinal detachment (2.21+/-0.72) than in the controls (2.01+/-0.72), although not significantly so. CONCLUSIONS: We found increased levels of NO pathway metabolites in the vitreous fluid of eyes with retinal detachment, which may reflect a possible role of NO in the pathogenesis of this disease.

Aged↗
PubMed2001

Vitrectomy results in diabetic macular oedema without evident vitreomacular traction.

PURPOSE: To determine the effectiveness of vitrectomy in eyes with diabetic macular oedema without evident traction from a thickened vitreous membrane. METHODS: Twenty-one consecutive eyes from 19 patients with diabetic macular oedema that had undergone vitrectomy were analysed retrospectively. All eyes had an attached posterior hyaloid membrane in the macular region, but without thickening and without evident traction on the macula. A standard pars plana vitrectomy with the creation of a posterior vitreous detachment was performed. RESULTS: Median duration of macular oedema at the time of vitrectomy was approximately 11.0 months (range 2-36 months). The median preoperative best-corrected visual acuity of 0.08 (range hand motions/0.003 to 0.4), improved by 5 lines to a median final postoperative best-corrected visual acuity of 0.25 (range 0.025-0.5) (P = 0.001). Seven eyes without preoperative macular photocoagulation had a median visual acuity improvement of 77%, range 32-400%, while 12 eyes with preoperative macular laser treatment had a median visual acuity improvement of 14.8%, range 0-66.1% (P = 0.02, CI 95%, after multivariate regression analysis). In all 21 eyes, macular oedema was no longer visible on microscopic examination after a median period of 3.0 months (range 1-9 months) after vitrectomy. CONCLUSIONS: In eyes with diabetic macular oedema without evident macular traction from a thickened vitreous membrane, vitrectomy resulted in the resolution of macular oedema, with an improvement in visual acuity in the majority of cases. Eyes without preoperative macular photocoagulation had a significantly higher percentage visual improvement than eyes without preoperative macular laser treatment. A randomised controlled prospective trial of primary vitrectomy versus macular photocoagulation is needed to determine the role of vitrectomy as treatment modality for diabetic macular oedema.

Adult↗
PubMed2000

Tractional retinoschisis in proliferative diabetic retinopathy: a histopathological study.

BACKGROUND: Proliferative diabetic retinopathy (PDR) often results in a tractional elevation of the retina. This study investigates the anatomical and histopathological structures of the vitreous body and the elevated retina in PDR. METHODS: Four globes (three patients) with PDR and known retinal elevation were analysed histologically. The tissues were embedded in celloidin and a special thick section technique (250 microm) was used for analysis under a stereomicroscope. RESULTS: All four cases showed adherence of the vitreous body with the retina and a tractional elevation of the retina at that site. In two cases retinoschisis was combined with retinal detachment and in the other two cases the retinal elevation was a pure retinal schisis. CONCLUSION: Our histopathological investigations of PDR show that traction of the retina by shrinking of the vitreous body may result in a combination of retinoschisis and retinal detachment at the same area. These cases are clinically often diagnosed as retinal detachment, but because of the additional retinal schisis they are of poor functional prognosis.

Adult↗
PubMed1980

Pars plana vitrectomy techniques for relief of epiretinal traction by membrane segmentation.

We used a technique for surgical management of fibrovascular membranes to relieve epiretinal tangential traction when present in proliferative diabetic retinopathy. Sharp dissection with intraocular scissors was used to segment fibrovascular and cortical vitreous membranes together with cauterization of large vessels with intraocular bipolar diathermy. The objective of membrane segmentation was to relieve all epiretinal traction, thereby reducing retinal surface distortion and allowing the retina to flatten and reattach. Complete relief of traction prevented further late contraction of membranes and subsequent distortion and redetachment.

Air↗
PubMed1988

Pathogenesis and therapy of traction detachment in various retinal vascular diseases.

We examined six patients with retinal vasculopathies (two cases each of angiomatosis retinae [von Hippel-Lindau disease], exudative vitreoretinopathy, and Coats' disease), who developed preretinal and vitreal membranes, retinal traction detachment, and exudation under the retina. The membranes consisted of a core of collagen of various diameter fibers usually covered on both sides by cells that displayed glial cell characteristics. The retina reattached spontaneously and exudates disappeared when traction was eliminated by vitreous surgery. Membrane formation did reoccur after vitrectomy if the vessels continued to leak, leading again to traction and subretinal exudation. Treatment consisted of surgical removal of vitreal and preretinal membranes and destruction of leaking vessels.

Adult↗
PubMed2001

Echographic evaluation of a patient with diabetes and dense vitreous hemorrhage: an avulsed retinal vessel may mimic a tractional retinal detachment.

PURPOSE: To report that an avulsed retinal vessel may appear as a tractional retinal detachment on echographic evaluation. METHODS: Case report. RESULTS: A 57-year-old diabetic woman presented with a nonclearing vitreous hemorrhage of 2 months duration in the left eye. Echography was consistent with a localized tractional retinal detachment on longitudinal sections; transverse sections demonstrated a pinpoint opacity in the vitreous cavity. Intraoperatively, an avulsed retinal vessel was noted in the area of echographic abnormality. CONCLUSION: An avulsed retinal vessel may mimic tractional retinal detachment on echography. Although trained ophthalmic echographers routinely perform both longitudinal and transverse sections during an echographic evaluation, less skilled observers must be aware of the importance of performing both longitudinal and transverse sections for accurate echographic diagnosis.

Diabetes Mellitus, Type 1↗
PubMed1980

Ultrastructure of traction retinal detachment in rhesus monkey eyes after a posterior penetrating ocular injury.

We studied the ultrastructural characteristics of an experimental model of traction retinal detachment secondary to a penetrating eye injury in the rhesus monkey. Cells with the characteristics of myofibroblasts were present in the intravitreal fibrous tissue and in epiretinal membranes. These cells were probably derived from many sources, and were capable of contraction through the mechanism of intracytoplasmic contractile proteins such as actin or myosin. The morphologic observations supported our hypothesis that traction retinal detachment is a cell-mediated event analogous to the processes of wound healing and wound contraction. The force of contraction is mediated by cell-to-cell and cell-to-vitreous connections and by glial bridges that connect epiretinal membranes to the retina. These ultrastructural studies, which provide insight into the pathogenesis of traction retinal detachment in the experimental animal model, may well have significant clinical relevance.

Animals↗