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PubMed1989

[Traction injuries of the brachial plexus: radiologic diagnosis using myelo-CT and MR].

The exact radiographic localisation of supraganglionic lesions of the brachial plexus provides important information for the prognosis and clinical management of these injuries. The authors report on the results of enhanced CT scanning and MRI of the cervical spine in five patients with surgically proven root avulsions caused by traction injuries. All lesions were correctly diagnosed by enhanced CT scanning. MRI, by comparison, identified only about 70% of the neural lesions.

Adult↗
PubMed1981

[The problem of dorsal spondylodesis while using traction rods (author's transl)].

Functional and morphological disturbances of health at the vertebral column lead to instability, dislocation and reduction of intervertebral distance in the mobile segment. A safe therapy to remove these changes must aim at achieving three goals: 1. Re-establishment of stability 2. Repositioning of slipped disks and 3. Re-establishment of intervertebral distance. Especially in spondylolisthesis, results are often unsatisfactory. Even if dorsal traction rods are used, the intervertebral bodies will often slip due to uncoupling in the vertebral joints. This situation can be avoided by effecting together with the introduction of bone blocks. This procedure enables satisfactory repositioning, full restoration of intervertebral distance and permanent restoration of stability.

Follow-Up Studies↗
PubMed1999

Keratocytes generate traction forces in two phases.

Forces generated by goldfish keratocytes and Swiss 3T3 fibroblasts have been measured with nanonewton precision and submicrometer spatial resolution. Differential interference contrast microscopy was used to visualize deformations produced by traction forces in elastic substrata, and interference reflection microscopy revealed sites of cell-substratum adhesions. Force ranged from a few nanonewtons at submicrometer spots under the lamellipodium to several hundred nanonewtons under the cell body. As cells moved forward, centripetal forces were applied by lamellipodia at sites that remained stationary on the substratum. Force increased and abruptly became lateral at the boundary of the lamellipodium and the cell body. When the cell retracted at its posterior margin, cell-substratum contact area decreased more rapidly than force, so that stress (force divided by area) increased as the cell pulled away. An increase in lateral force was associated with widening of the cell body. These mechanical data suggest an integrated, two-phase mechanism of cell motility: (1) low forces in the lamellipodium are applied in the direction of cortical flow and cause the cell body to be pulled forward; and (2) a component of force at the flanks pulls the rear margins forward toward the advancing cell body, whereas a large lateral component contributes to detachment of adhesions without greatly perturbing forward movement.

Actins↗
PubMed2002

Directional control of lamellipodia extension by constraining cell shape and orienting cell tractional forces.

Directed cell migration is critical for tissue morphogenesis and wound healing, but the mechanism of directional control is poorly understood. Here we show that the direction in which cells extend their leading edge can be controlled by constraining cell shape using micrometer-sized extracellular matrix (ECM) islands. When cultured on square ECM islands in the presence of motility factors, cells preferentially extended lamellipodia, filopodia, and microspikes from their corners. Square cells reoriented their stress fibers and focal adhesions so that tractional forces were concentrated in these corner regions. When cell tension was dissipated, lamellipodia extension ceased. Mechanical interactions between cells and ECM that modulate cytoskeletal tension may therefore play a key role in the control of directional cell motility.

3T3 Cells↗
PubMed1987

Suction cannula assisted placement of traction sutures.

Many reconstructive techniques require placement of autogenous tissues or temporary implants into large subcutaneous cavities. This procedure may be facilitated by using traction sutures for their insertion. The blunt suction lipectomy cannula in turn can simplify this tedious step by providing a means to pass these sutures over long distances. The technique for this simple and time-saving procedure is described.

Humans↗
PubMed1999

Muscle bow traction method for dynamic facial reanimation.

A muscle bow traction method was developed for dynamic facial reanimation utilizing the masseter muscle and a fascial sling. The principle of this method is that the sling around the muscle pulls the oral commissure laterally and backward by the restoring force of the muscle from its relaxed position to its contracted position. The surgical procedure is simple. The sling is passed around the anterior half of the muscle so that the muscle can be bowed anteriorly at its center by the sling. One end of the sling is sutured to the center of the orbicularis oris and the dermis in front of the nasolabial fold, and the other end is sutured to the lower lip and oral commissure. This method was applied to 3 patients with facial palsy and to 1 patient with oral cancer. The restored motion of the oral commissure ranged from 5 to 8 mm when clenching the jaws. The concept of this method differs from those of other muscle transposition methods for facial reanimation in that the force acts at a right angle to the muscle contraction. The advantage of this method is that it is less invasive to the muscle and is a simpler procedure than other conventional muscle transposition methods.

Aged↗
PubMed1994

Traction suture for canalicular lacerations.

Maintaining good wound closure in canalicular lacerations is difficult because of the horizontal tension exerted by the orbicularis muscle on the wound. A method of placing a deep medial canthal traction suture through the medial orbital periosteum to aid in maintaining good wound approximation is presented.

Adult↗
PubMedDate not supplied

Traction injuries of the brachial plexus: signal intensity changes of the posterior cervical paraspinal muscles on MRI.

PURPOSE: Our goal was to evaluate MR signal intensity change of the posterior cervical paraspinal muscles in brachial plexus traction injuries to determine the value of this finding in the diagnosis of nerve root avulsion. METHOD: MR images of 11 consecutive patients, 7 with nerve root avulsion and 4 without nerve root avulsion, were retrospectively analyzed, focusing on the signal intensity of the paraspinal muscles. RESULTS: Among the seven patients with nerve root avulsion, T2- or T2*-weighted MR images showed increased signal intensity in the deep posterior paraspinal muscles in five and traumatic meningocele in four. The signal intensity of the posterior paraspinal muscles was normal in all patients without nerve root injuries. CONCLUSION: MR signal intensity change in the deep posterior cervical paraspinal muscles is related to denervation and suggests the presence of nerve root avulsion.

Accidents, Traffic↗
PubMed1991

Further experience in rehabilitation of zone II flexor tendon repair with dynamic traction splinting.

A review of all flexor tendon repairs in the "no man's land" performed from January of 1985 to June of 1987 was done to evaluate the efficacy of our method of rehabilitation. There were 60 fingers (57 patients) with complete laceration of the flexor digitorum profundus and flexor digitorum superficialis tendons in zone II. Fingers with phalangeal fractures, joint injuries, or significant skin loss were excluded. Follow-up ranged from 12 to 48 months. Rehabilitation consisted of a 12-week protocol using the U.S. military combined regimen of controlled motion. Features from the technique of controlled active extension against rubber band passive flexion as well as those of controlled passive extension and passive flexion were incorporated. The palmar pulley modification of Kleinert's dynamic traction splint was utilized. Strickland's total active motion formula was employed to determine results. The results were classified into the four categories of excellent, good, fair, and poor. Fifty-two fingers (86 percent) were rated excellent, 4 fingers (7 percent) were rated good, 1 finger (2 percent) was rated fair, and 3 fingers (5 percent) were rated poor.

Exercise Therapy↗
PubMedDate not supplied

Treatment of combined traction-rhegmatogenous retinal detachment in the morning glory syndrome.

A 14-year-old boy had a near total retinal detachment associated with the morning glory optic disc anomaly. A tiny slit-like retinal break with adjacent vitreous traction was found within the coloboma, providing communication between the vitreous cavity and the subretinal space. Vitrectomy, fluid-gas exchange, and postoperative confluent Krypton laser photocoagulation around the optic disc resulted in a successful reattachment of the retina. The retina has remained attached for 14 months.

Adolescent↗
PubMed1989

Management of anterior vitreous traction in proliferative vitreoretinopathy.

The major cause of failure in retinal detachment surgery is proliferative vitreoretinopathy. The surgical treatment of proliferative vitreoretinopathy has improved dramatically over the past ten years. Still failure is too common and the need for reoperation remains high. We believe this is often due to anterior vitreous traction. We report our present "conservative" surgical approach to treating such patients using newly developed fiberoptic instrumentation. Using this approach, we have achieved total retinal reattachment in 42 of 48 patients with C3 or greater proliferative vitreoretinopathy with six months or greater follow up.

Eye Diseases↗
PubMed1990

Retinal detachment in highly myopic eyes due to macular holes and epiretinal traction.

We operated on four highly myopic eyes with recurrent retinal detachment due to macular holes. A thin layer of epiretinal tissue was present over the posterior retina in each eye, probably causing tangential traction on the retina and accounting for the recurrent detachment. Biopsy of the tissue from one case showed mainly acellular material resembling cortical vitreous. Recognizing this clinical condition may permit successful treatment of certain cases with recurrent retinal detachment in highly myopic eyes with macular holes.

Adult↗
PubMed1998

Vitreomacular traction syndrome following highly active antiretroviral therapy in AIDS patients with cytomegalovirus retinitis.

PURPOSE: To report the development of vitreomacular traction syndrome (VMT) following highly active antiretroviral therapy (HAART) in AIDS patients with cytomegalovirus retinitis (CMV-R). METHODS: We identified two AIDS patients with evidence of CMV-R who later developed VMT following HAART-associated immune recovery vitritis. RESULTS: The CD4+ T-lymphocyte count increased from 5 to 190 cells/microL in Patient 1 and from 26 to 713 cells/microL in Patient 2. HIV-RNA copies/mL decreased from 341,000 to less than 400 in Patient 1 and from 43,900 to less than 400 in Patient 2. Increased vitreous inflammation occurred during this period of immune recovery. After resolution of vitritis, VMT developed in both patients and was confirmed by B-scan ultrasound and fluorescein angiography. In both patients, CMV-R was clinically inactive at the time of VMT development. Both patients underwent pars plana vitrectomy with peeling of the posterior hyaloid, which confirmed VMT intraoperatively. CONCLUSIONS: VMT appears to be a sequelae of HAART-associated immune recovery vitritis in AIDS-related CMV-R. Changes in immune status may permit an inflammatory response that can lead to VMT. As advances in pharmacologic intervention continue, clinical manifestations and ocular sequelae in CMV-R will change, as will the approach and management of this disease.

AIDS-Related Opportunistic Infections↗
PubMed2000

Ultrastructural and immunohistochemical findings in five patients with vitreomacular traction syndrome.

OBJECTIVE: To evaluate pathologic features of vitreomacular traction syndrome (VMT). METHODS: Preretinal membranes removed from five patients during vitreous surgery for VMT syndrome were evaluated by electron microscopy (n = 4) and immunohistochemistry (n = 1). RESULTS: Electron microscopic examination revealed large segments of internal limiting lamina (ILL) in three of the four cases. Other extracellular features included two types of abnormal collagen fibrils, determined to be type I and fibrous long-spacing collagen. The myofibrocyte was the predominant cell type in all cases. Collagen types I, II, and III, as well as glial fibrillary acidic protein and vimentin, were identified by immunohistochemistry. CONCLUSIONS: Epiretinal membranes in eyes with VMT syndrome adhered tightly to the ILL with abnormal collagen and contractile elements that included myofibrocytes.

Aged↗
PubMed2005

Posterior traction retinal detachment in highly myopic eyes: clinical features and surgical outcome as evaluated by optical coherence tomography.

PURPOSE: To investigate the correlations between the clinical characteristics of macular detachment without holes or posterior breaks and functional outcomes as evaluated by means of optical coherence tomography (OCT) in patients with highly myopic eyes after pars plana vitrectomy. METHODS: This retrospective study describes the preoperative and postoperative visual acuity, and OCT and FAG images of seven highly myopic eyes (range: -10 to -24 diopters [D]) with a symptomatic decrease in visual acuity that were surgically treated by means of pars plana vitrectomy. RESULTS: The intraoperative observations confirmed the OCT findings. The macula was reattached after surgery in 85.7% of cases; visual acuity improved in six eyes and worsened in one. The only postoperative complication recorded was nuclear sclerosis (60% of the cases). CONCLUSIONS: OCT should be considered mandatory in the diagnosis and follow-up of posterior traction retinal detachment without a macular hole or posterior break in highly myopic eyes. A posteriorly detached retina can be reattached surgically, but visual improvement may be limited by the presence of other chorioretinal myopic lesions and persistent cystoid macular changes.

Aged↗
PubMed1992

Changes in arterial blood pressure during traction of extra-ocular muscles. A study in rabbits.

A significant reflex fall in mean arterial blood pressure from baseline values was observed during extra-ocular muscle traction in rabbits. This effect could be abolished only by retrobulbar block (afferent pathway block) and not by vagotomy, intravenous atropine or glycopyrronium, suggesting that it is distinct from, and independent of, the oculocardiac reflex. We suggest that these reflex changes in blood pressure be known as the 'oculodepressor reflex'.

Animals↗
PubMed1998

Vasopressor hormone response following mesenteric traction during major abdominal surgery.

BACKGROUND: We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI2) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. METHODS: In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGF1 alpha (stabile metabolite of PGI2), TXB2 (stabile metabolite of thromboxane A2) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. RESULTS: Following MT, arterial hypotension occurred along with a substantial PGI2 release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF1 alpha (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P = 0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB2 (164 (87) vs. 58 (1) ng/L, P = 0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P = 0.001), AVP (41 +/- (18) vs. 12 (7) ng/L, P = 0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. CONCLUSION: Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI2 release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A2, presumably contributing to hemodynamic stability within 30 min after MT.

Abdomen↗
PubMed2005

Evolutionary traction: the cost of adaptation and the evolution of sex.

The advantage of sexual reproduction remains a puzzle for evolutionary biologists. Everything else being equal, asexual populations are expected to have twice the number of offspring produced by similar sexual populations. Yet, asexual species are uncommon among higher eukaryotes. In models assuming small populations, high mutation rates, or frequent environmental changes, sexual reproduction seems to have at least a two-fold advantage over asexuality. But the advantage of sex for large populations, low mutation rates, and rare or mild environmental changes remains a conundrum. Here we show that without recombination, rare advantageous mutations can result in increased accumulation of deleterious mutations ('evolutionary traction'), which explains the long-term advantage of sex under a wide parameter range.

Adaptation, Biological↗