Kushandisa Kwakakodzera Kwechivharo Plate!

A Locking plate mudziyo wekugadzirisa kuputsika une buri rine thread. Kana sikuruu ine musoro wakarukwa ichipindirwa mugomba, ndiro inova (screw) angle fixation device. Iro yekukiya (yakadzikama) ndiro inogona kuva nemaburi ekukiya neasingavhare kuti masiruuru akasiyana apinzwe mukati (inonziwo ndiro yakasanganiswa). Sezvo pfungwa yekuvhara mahwendefa yakarongedzerwa uye yakashandiswa pakurapa kuputsika, yakashandiswa zvakanyanya mukugadzirisa kuputika kweperiarticular fractures, comminuted uye osteoporotic fractures nekuda kwezvakanaka zvayo zvekupa rubatsiro rwakagadzikana uye kugadziriswa kwezvipembenene, kuwedzera kwepamusoro kupora kupora, kuderera kuduku kwetishu uye kukanganiswa kweropa. Kuverenga kwanhasi kwemangwanani kuchakupa sumo yakadzama yekukiya mahwendefa, ayo akakodzera kudzidza kubva!

(A)Basic Overview

1.Chii chinonzi chekuvhara ndiro?

Chero ndiro yesimbi inogona kukwizwa kuita makona ekugadzirisa/makona ekudzikamisa masiruu kana mapini inenge iri ndiro yekukiya.

2. Zvakanakira uye zvisingabatsiri zvekuvhara mahwendefa

Zvakanakira

∎ Angular kugadzikana, kuramba kukotama uye torsion

■ Conical chimiro chescrew head inovandudza kugovera kwemichina

■ Ipa radial preload, kudzivirira kudzoreredzwa kwebhonzo uye kusunungura sikuruu

∎ Yakaumbwa neanatomical kuti ienderane nemaitiro enzvimbo yeanatomical mapatani

■ Kufananidza matemplate kubvumidza percutaneous gadziriso mudiaphysis (imwe cortical, yekuzviboorera, self-tapping yekukiya screws)

■Masiruu ekukiya anopa anchorage yakanaka kune ese ari maviri bhiriji anochinjika uye absolute kudzikamisa kugadzirisa.

∎ Hapana chikonzero chekuswedera pedyo nepamusoro pebhonzo, kuchengetedza ropa

∎ Inodzorwa micromotion, ichifarira kuporeswa kwekutyoka

■Kazhinji hapana kubatanidzwa kwebhonzo kunodiwa

Iyo inonyanya kushanda kune osteoporotic fractures kana chero yakanyanya kusagadzikana fractures.

Zvakaipa

■ Kukiya masiruru haana kudzikisira uye compression maitiro, kunyanya mu intra-articular fractures kana nyore oblique fractures.

■ Ndiro haigone kushandiswa sechombo chekudzikisa kubatsira mukuderedza.

■Masiruuru haanzwe zvakanaka semasiruuru emazuva ose kana akaiswa.

■ Kutungamira kwezvikwiriso hakugone kugadziridzwa (kunze kwemultiaxial locking screws).

■Masiruuru akaiswa zvakasimba, izvo zvinogona kutungamirira ku 'kutonhora welding'.

■ Kutsauka kwekona > 5 °, kupera simba; > 10 °, kuvhara maitiro haashande

∎ Zvinogoneka subcutaneous protrusion kana ndiro isina kutenderedzwa

Nyaya dzekuoma musoro

Pasina yakanaka cortical kuonana kana kuomeswa kwekuputsika kunopera, kushandiswa kwekukiya splints, kunyanya simbi isina tsvina, inodzivirira chikamu chechipiri kuporeswa kwekutyoka nekuda kwekuomarara kwakanyanya uye kubviswa kweiyo yakanaka micromotion panzvimbo yekuputsika;

Kana intraoperative traction ikashandiswa uyezve kuvhara splint fixation inoshandiswa, gap rekuputsika richachengetedzwa, zvichikonzera kunonoka kana kusaporeswa kwekuputsika;

Kana kuputsika kuri nyore kusina kugadziriswa uye kumanikidzirwa, mutoro unoparidzirwa kuburikidza neplate, zvichiita kuti kuve nekunetseka kwepfungwa kunogona kutungamirira nyore nyore kuputsika kweplate.

3. Kusiyana kukuru kwebiomechanical pakati pekuvhara mahwendefa uye mahwendefa akajairwa

Mahwendefa akajairwa anovimba nekukweshana pabhonzo-plate interface kuti iite kudzvanywa kweplate yebhonzo.

4. Kuenzanisa kwakanakira yekuvhara ndiro uye yakajairwa simbi ndiro

1.Kudhonzera-kunze kwekupokana kwekuvhara screws kwakakwira zvakanyanya kupfuura kweakajairika screws.

2. Epiphyseal locking screws inosungirirwa kune imwe neimwe, iyo inowedzera zvakanyanya kupikisa kwescrew kudhonza kana ichienzaniswa neparallel screws.

(B) Mitemo yekushandisa

1. Misimboti yekumisa:

● Pressurization nheyo: osteoporotic diaphysis fracture

● Neutralization nheyo: osteoporotic diaphysis fracture

● Bhiriji musimboti: comminuted diaphysis kana extra-articular metaphyseal fracture

Nheyo yekubatana: yakagadziriswa intra-articular metaphyseal fracture

2. Bridging musimboti:

●Maitiro akajairika: percutaneous minimally invasive plate fixation (MIPO kana MIPPO maitiro)

●Unyanzvi hwekuderedza husina kunanga

●Pakugadziriswa kweplateti yebhiriji yakakwana, 3-4 screw holes inofanira kusiiwa yakashama pedyo nekunogumira.

3. Misimboti yemubatanidzwa:

● Kusanganiswa kwekushandiswa kwemaitiro maviri ebiomechanical ekumanikidzana uye bhiriji mundiro imwe chete - locking compression plate (LCP)

● Kutyoka kuri nyore mune chimwe chikamu chekutyoka uye kuputika kwakaputika mune imwe (semuenzaniso, kuputika kwemetaphysis, diaphysis)

● Nheyo yekubatana inofanira kushandiswa chete kumaplateti anobvumira kuiswa kwezvose zviri zviviri zvekukiya musoro screws pamwe chete neakajairika screws.

Kukiya mahwendefa haavimbe nekukweshana pakati pebhonzo-plate interface uye anonyanya kutsamira pane interface pakati pesiruu nendiro ine angular kugadzikana kuchengetedza kugadzikana.

Nekuda kwekubatana kwadzo kwakadzikama, simba rekubvisa remasiruu rine misoro yakavharika rakakwirira zvakanyanya kupfuura rezvivharo zvakajairika, kunze kwekunge ese akatenderedza screws aburitswa kana kutyoka. Kazhinji, zvakaoma kuti screw imwe chete ibudiswe kana kutyoka yega. Kukiya musoro screws hazvipi inter-fold pressurization. Pressurization inogona kuwanikwa nekushandisa muchina wekudzvanya kana kutyaira screws dzenguva dzose mu 'mixing holes' (tension screws kutanga, wozokiya zvipikiri).

1.Kana zvidzitiro zvakajairika zvakashandiswa kuchengetedza splint (eg 1), kupuruzira mumakona ekukiya kuchava nyore kwazvo (eg 2).

2.Kana zvivharo zvekuvhara zvakashandiswa kuchengetedza splint uye bone block (eg, 1), hazvikurudzirwi kuti zvigadziriswe zvigadziriswe mubhokisi rimwe chete remapfupa (semuenzaniso, 2) kunze kwekunge zvivharo zvekuvhara zvasunungurwa uye zvakasimbiswa zvakare (LHS).

3.Kana metaphyseal fracture block yakachengetedzwa nescrew ine musoro wekuvhara (LHS), kugadziriswa kwekugadzirisa pakati pezvivharo zvekuputsika kunowanikwa kuburikidza nekuputira screw standard mugomba rekugadzirisa simba reLocking Compression Plate LCP kusanganiswa.

(C) Zvinoratidza uye contraindications

1. Zviratidzo

Mazhinji akavhiyiwa mafractures haadi kukiya ndiro kugadzirisa. Chero bedzi misimboti yekuvhiyiwa kwemapfupa ichitevedzwa, kutsemuka kwakawanda kunogona kuporeswa nemahwendefa akajairika kana intramedullary nailing.

Zvisinei, kune marudzi akasiyana-siyana ekutsemuka anokonzerwa nekurasikirwa kwekuderedza, ndiro kana screw breakage, uye inotevera nonunion, inowanzonzi 'zvisina kugadziriswa' kana 'problematic' fractures, kusanganisira intra-articular comminuted fractures, periarticular fractures nediki fractures, bone fractures. Aya marudzi ekutsemuka anowanzo kunzi 'zvisina kugadziriswa' kana 'dambudziko' fractures uye inosanganisira intra-articular comminuted fractures, periarticular short tuberosity fractures uye osteoporotic fractures. Kutyoka uku zviratidzo zvese zvekukiya mahwendefa.

Iyo yemhando yepamusoro uye yakanakira zviratidzo zvekukiya ndiro kugadzirisa kwekutyoka ndiyo musimboti webhiriji uye musimboti wemubatanidzwa wemamwe mafractures akawedzera - kutsemuka kwesimba muvarwere vadiki kana osteoporotic fractures muvarwere vakura.

2. Contraindications

Kunyangwe mahwendefa ekukiya ave achishandiswa zvakanyanya uye zviratidzo zvawo zvakapamhama, isu tinofanirwa kuziva nekudzivirira akati wandei zvinopesana nekuvhara ndiro. Kana mahwendefa ekuvhara akashandiswa zvisina kusarudzwa, kukundikana kwekugadzirisa uye kusabatanidzwa kwekuputsika kunogona kuitika.

Kutsemuka kwakapusa kunoda kudzvanywa kwemukati, senge nyore forearm stem fractures inobatwa nekuvhara mukati mekugadzirisa, inowanzoitika kune isiri-mubatanidzwa.

Saizvozvo, percutaneous kuiswa kwekuvhara mahwendefa ezvimedu zvakapfava uchishandisa zvishoma zvinopinda maitiro zvakare zvinopesana.

Kudzikisira kusinganangi uye kukiya kwendiro yekumisikidza zvakare haina kukodzera kune akatamiswa intra-articular fractures, izvo zvinoda kuvhurika anatomical kuderedzwa uye kudzvanya pakati pezvimedu zvekutyoka uye kugadzirisa kwakasimba.

Chimwe chinopesana nekuvhara mahwendefa, nekuda kwekudhura kwavo kukuru, kuputsika kunogona kugadziriswa zvinogutsa nemahwendefa akajairwa. Semuenzaniso, kuputsika kwe forearm symphysis kune chiyero chekuporesa chinopfuura 90% kana ichirapwa nemahwendefa akajairwa.

(D) Kuiswa kwekuvhara ndiro

1. Kirai chibooreso mumaburi epaplate. Kutsauka kwe> 5° pakati pesiruu nescrew hole kunogona kukonzera kutadza kukiya kukiya, uye zvinokurudzirwa kushandisa dhiri kuboora maburi zviri nani.

2. Isa ndiro yesimbi pamusoro pebhonzo uye uboora maburi kuburikidza nesleeve yekuchera.

3. Edza kudzika nezwi rakadzika, uchichenjerera kuti musoro wezwi unopinzwa mugomba rekupura.

4. Sarudza urefu hwakakodzera hwekona yekuvhara.

5. Kuiswa kwezvisungo zvakatsikirirwa kwakafanana nemahwendefa esimbi akajairika.

6. Pakupedzisira simbisa zvivharo zvekuvhara ne torque wrench, kana yakasimbiswa, pachava nekunzwa kutsvedza kwakajeka uye kurira kwezwi, kudzivisa kupinza mukati zvakanyanya, zvichiita kuti kubvisa matambudziko.

(E) Kukiya ndiro kubviswa

Clinical locking plate screws anoshandiswa zvakanyanya, asi zviri nyore kusangana nekubvisa matambudziko, anonyanya kuratidzwa mu screw inotsvedza waya uye chipikiri chivharo neplate mbambo tambo pakati pebhangi risiri iro.

1. Screw cap groove kukuvara

Mumamiriro ezvinhu akajairwa, iyo yakazara screw cap groove uye inoenderana screwdriver inoenderana. Iyo screwdriver inofanirwa kuwiriraniswa nescrew cap groove isati yaiswa kana kubvisa sikuruu, zvikasadaro screw cap groove ingangoremara panguva yekukwesha mukati kana screwing kunze, zvichikonzera kutsvedza.

Pamusoro pezvo, mushure mekuporeswa kwekutyoka, screw cap notch inowanzoputirwa nepfupa crust kana fibrous tissue, iyo inofanirwa kucheneswa isati yabvisa screw, asi kana pasina kutariswa kwakabhadharwa, screw cap notch uye chimiro cheangular chinogona kukuvadzwa.

Nekuti kutenderedza axis ye forearm yemushandisi haienderane neakisisirudhiraivha yakareba axis, kazhinji pane imwe kona, kana mushandisi akaburitsa nechisimba screw, hazvidzivirike kuti screwdriver inozununguka, zvichikonzera kukuvadzwa kune cap groove ye screw nekuda kwesimba risina kuenzana. Naizvozvo, kukuvadzwa kwescrew groove kunogona kutungamira nyore kune screw slippage.

2. Chivharo chembambo kana chembambo deformation

Mukuita intraoperative application yeanatomical yekuvhara simbi ndiro, nguva nenguva zvichienderana nekudikanwa kwekukotama kwakakodzera kana kuumbwa kwesimbi ndiro, Raja et al. tenda kuti kana chikamu chekukotama chikaitika mumaburi ekukiya, kana screwing muakavharira screws ichava sikuruu chivharo uye mbambo yembambo kusapindirana, izvo zvinonyanya kuitika pakati pechivharo chivharo uye simbi ndiro mbambo mbambo tambo dzisina kunaka, kana screwed pedyo nendiro yesimbi apo muswe wembambo deformation inokonzerwa nekukasira kwakasimba, zvichingodaro, izvo zvinogona kutungamira kubviswa kwakasimba gare gare.

3. Kushandiswa kwe-self-tapping cortical locking misumari

Nekuti bhonzo recortical rinokura mukati richitevedza gomba rezvipikiri uye nekudaro richabata sikuruu, zvichizotungamira mukunetseka mukubvisa sikuruu, kunyanya kushandiswa kwekuzvirova-rova kaviri cortical bone screws, Suzuki et al. usakurudzire kushandiswa kwega-tapping screws yekaviri cortical fixation. Hou Yunfei et al. yakaratidza kuti zvisingakoshi bicortical fixation ine screws inofanira kudziviswa nokuda kwekutsemuka kwepamusoro, uye Maehara et al. yakapawo zano rekuti kugara uchishandiswa kwekukiya masiruru kunofanirwa kudziviswa kana uchishandisa mahwendefa ekukiya, uye kuti pane kudikanwa kwekumisikidza mwero wepasirese wekusarudza nekushandisa kwekuvhara screws.

4. Chimiro uye nzvimbo ye screws

Saizi, kutaridzika, uye nzvimbo yekukiya screw inogona kukanganisa kubviswa kwe screw. Dzimwe nyanzvi dzakaona kuti kana sikuruu isina kuwanikwa pakati pegomba rekukiya, kana gomba rezvipikiri eccentricity inopfuura 5 ° panogona kunge paine yakasununguka screw fixation, shinda zvisirizvo buckle kana chipikiri muswe deformation inonamira uye inotungamira mukutadza kugadzirisa kana chikamu chechipiri chekubviswa kwematambudziko.

5.Cold welding

Yakajairika titanium yemukati yekumisikidza nzvimbo ine musara wepassivated yekudzivirira layer, mukuita kwekuvhiya kuiswa kwemukati mekugadzirisa, nekuda kwezvishandiso zvekubata uye kuumbwa, kana musoro wescrew uye kupokana pakati pesimbi ndiro, nezvimwewo, zvinogona kutungamira kune passivated yekudzivirira layer yekupfeka nzvimbo. 2 simbi yekuonana pamusoro pepakati peiyo substantive yekuonana nzvimbo inozoteedzerwa, ndiko kuti, kuumbwa kwekutonhora kwemoto.

Mukuwedzera, galvanic coupling pakati pesimbi ions, maitiro ekuputika, nezvimwewo zvinogonawo kukurudzira kuumbwa kwechando chelds. Vazhinji vagadziri vezvigadzirwa zvemukati zvekugadzirisa vanozivawo nezvedambudziko iri, uye nekudaro mahwendefa esimbi asina kushandiswa akavharwa akafukidzwa neoxyde film tekinoroji pakati pemaburi ezvipikiri uye screw contact surfaces, iyo inovavarirawo kurambidza ionization uye adsorption yemapuroteni mumuviri uye kuderedza kuitika kwekutonhora welds.

(F) Kubvisa maitiro

Maitiro ekubvisa anoshumwa mumabhuku enyika nepasirese anogona kupatsanurwa muzvikamu zviviri, zvinoti, zviri nyore uye zvinoshanda uye zvakaoma, izvo zvekare zvinoratidzwa nekusvikika nyore, kuita, kuderera kwenyama yakapfava kukuvadzwa, hunyanzvi hwakaderera uye pasina kudiwa kwezviridzwa zvakakosha, uye yekupedzisira ichida yakasarudzika chiridzwa nemidziyo.

Maehara et al. kurudzira kushandisa torque-kumisa screwdrivers ane shanks hombe pese pazvinogoneka. Paakatarisana neakatsvedza screws, Pattison et al. yakashuma nzira yakapfava yekubvisa masiuruu akatsvedza nekuputira musoro wescrewdriver nesimbi yeplatinamu nekuipinza mugomba rescrew cap. Iyi nzira yakangwara yekuzadza screw cap groove nesimbi foil uye kuwedzera nzvimbo yekubata uye kukweshana pakati pescrewdriver uye groove, izvo zvinofambisa kubviswa kwe screws neshinda dzakatsvedza. Munzira iyi zvichiri kunetsa kubvisa iyo kesi, kana screw cap uye simbi ndiro mbambo yembambo shinda ichiri yakasimba, unogona kuedza kushandisa conical reverse tapping screw remover, kureva, kubva kune screw cap groove inopinzwa mune reverse tapping uye kuzadza groove, mukuita kutenderera uye kumanikidza sikuru kunze.

Pazasi, mamwe masiruu ekukiya achiri kunetsa kushanda uchishandisa conical reverse tapping screw extractor, senge Ehlinger et al. uye Bae et al. uyo akaona kuti nzira iyi yaiwanzoshanda 3.5 mm screw slippage, asi kazhinji isingashande kune 4.5 mm screw slippage. Muchiitiko ichi, haisi nhanho dzese dzechipatara che orthopedics dzakashongedzerwa nemichina yekukuya simbi yakadai sema carbide drills, madhaimani, kana mavhiri ekukuya anomhanya.

Gopinathan et al. suma nzira isingade izvi zvehunyanzvi nekutaura nyaya yekuomerwa nekubviswa sikururu kubva mundiro yekuvakazve, kureva, uchishandisa yakaderera cutout yendiro yekuvakazve, hombe yekucheka waya inoshandiswa kugera chikamu chakatetepa chendiro pakati pemaburi ezvipikiri, kuitira kuti screws uye buri rezvipikiri chikamu cheplate chiite chidimbu chidiki, uye nyore kubviswa. Iyi tekinoroji inongoshanda kune titanium yekuvakazve yekukiya mahwendefa, forearm yekuvhara mahwendefa ane yakamanikana yakaderera notches, uye 1/3 chubhu-mhando mahwendefa, uye haigone kushandiswa kune yakafara kana yakakora mahwendefa muzasi kumucheto.

Nzira yakapfava yakatsanangurwa zvakare apo chibooreso chakati kurei chinoshandiswa kuboora buri mugomba rinowanikwa padyo nekasiruu yakatsvedza yekuvhara, uyezve ndiro nescuru zvinonamirwa kwakanangana negomba richangobva kuboorwa, uye ipapo ndiro nescuru zvinobviswa nekushandisa bhonzo rekuchekwa rinoiswa pasi pendiro uye kuibvisa nemusimboti wekusunungura.

Zvechokwadi, kune mukana wekukuvara kwepfupa nenzira iyi, saka mushure mekushanda uremu-kutakura kuchengetedzwa kunokurudzirwa. Pamusoro pezvo, zvinodikanwawo kugadzirira mamwe maturusi anowanzo shandiswa musati mavhiyiwa emukati ekubvisa, senge bolt extractor, hole reamer, screw extraction pliers, T-type pressurized socket zvichingodaro.

Mukutarisana nekukiya sikuruu inotsvedza kubviswa kwewaya, dzimwe nyanzvi dzepamba dzakaronga kushandura nzira yegorofu, ndiko kuti, kushandiswa kwemazino micro-kugaya muchina simbi jecha chidimbu kushandura sikuruvha chivharo groove hexagonal kana quadrangular groove 'rimwe' kana 'gumi ' groove, kana kudzika yepakutanga groove.

Ehlinger et al. yakashuma kuti panguva apo conical reverse tapping screw extractor ichiri kunetsa kubvisa sikuruu, zvakanzi ndiro yesimbi yaigona kubviswa nekuparadza musoro wesiruu netungsten drill kugaya nekukudza maburi ezvipikiri mundiro yesimbi, uye ipapo muviri wesiruu waigona kubviswa nekushandisa ring saw.

Georgiadis et al. uye Raia et al. zvinokurudzirwa mu sikuruu nendiro yendiro musanganiswa wakanyanya kusimba uye zvakaoma kubvisa, yakakosha midziyo (yakadai sepneumatic high-speed cutting drills, carbide drills, diamond mavhiri, etc.) paburi rezvipikiri rakakomberedza nzira yekucheka ndiro yesimbi, mundiro yesimbi inochekwa kuti isunungure sikuru, iyo sikururu zvakare zviri nyore kubvisa.

Kumar naDunlopl vakashuma mune distal femur locking simbi plate screw system yemukati fixation yekubvisa maitiro, mukushandiswa kweyakajairwa self-limiting torque screwdriver, conical screw extractor yakundikana, asi zvakare yakaunza nzira nyowani, kureva, kushandiswa kwepamusoro-kumhanya mutete-flake mavhiri abrasive kumucheto kwendiro yesimbi kusvika kumucheto kwesiruuru, k buri muburi uye radial. usavhure simbi ndiro chipikiri gomba kuitira kuzorodza chivharo, kuitira kuti zvinobudirira kubvisa Locking screws.

Zvakakosha kuziva kuti nzira dziri pamusoro apa dzinofanirwa kufambiswa zvishoma nezvishoma panguva yekucheka kana kugaya kweplate uchishandisa dhisiki yepamusoro yekucheka kuti urege kucheka mumusoro we screw uye kukuvadza pfupa uye zvinyoro zvinyoro. Pamusoro pezvo, matekiniki aya anogona kuburitsa tembiricha yakakwira uye marara esimbi, izvo zvinogona kukonzera njodzi yakawedzera yekutyokazve kwemishonga, tishu thermal necrosis, uye hutachiona.

(G) Pfupiso

■ Bvumira ndiro isina kukwana neperiosteum

■ Indiro inofanira kuiswa patsva isati yavhara, sezvo kuputsika hakugoni kuiswazve mushure mekuvhara.

■ Kukiya ndiro haigone kudzvanywa, inoda kushandisa pressurizer kana centrifugal screwing mugomba remubatanidzwa mukati mesiruu zvakajairika, kutanga kudzvanywa, wozokiya.

■ Fracture site 3 ~ 4 screw holes pasina screws kuparadzira kushushikana; ■ Fracture site 3 ~ 4 screw holes pasina screws kuparadzira kushushikana; uye

■ monocortical fixation ye diaphysis kana gobvu bone cortex, uye apo kunaka kwebhonzo kwakanaka; uye

■ Kana yangovharwa, haikwanise kuvharirwa kunze, nepo masiruuru akajairwa achigona kutsigirwa

■ Kugadziriswa kwakasimba uye screws dzakawandisa zvinogona kutungamirira kukusabatanidzwa; musimboti ndewekuti mahwendefa anofanira kunge akareba uye mashoma screws anofanira kushandiswa; mukurapa kweperiarticular fractures, mashoma screws anofanirwa kuiswa pazinde uye mamwe ma screws anofanirwa kushandiswa kugadzirisa kutarisana ne articular surface.

■ kureba kweplate yebhiriji kunofanirwa kunge kwakapetwa kaviri kureba kwenzvimbo yakatsemuka, screws dzinofanira kugoverwa zvakaenzana, uye iyo yakakodzera kugadzirisa inofanira kunge iri kuburikidza-iyo-aperture fixation.

∎ Simba rinogovaniswa zvakaenzana pandiro refu, uye kugadzikwa nemascruu mashoma kunogona kukurudzira kugadzirwa kwegwenga uye kukurudzira kupora kwemapfupa.