3.1.3 Minimally invasive surgery

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1 Authors Reto Bst, Kok-Sun Khong Minimlly invsive surgery 1 Introduction Minimlly invsive procedures with limited surgicl trum to soft tissues nd one hve een pplied to frcture mngement for long time. Smll pproches nd indirect reduction techniques without exposure of the frcture focus hve iologicl dvntges not only for frcture heling ut lso for the whole ody, s demonstrted y dmge-control surgery in the polytrumtized ptient. Closed intrmedullry niling of diphysel frctures using short incisions nd indirect reduction usully results in undistured frcture union y cllus formtion. Erly dvoctes of iologicl osteosynthesis y ridge plting [1, 2] demonstrted tht when indirect reduction ws comined with internl splinting with long pltes for frctures of the epi-/metphysis extending into the femorl shft, there ws similr pttern of undistured one heling with cllus formtion s with intrmedullry niling, regrdless of the length of incision. For the ntomicl reconstruction of rticulr frctures the pproch must e lrge enough to give n dequte view of the joint surfces; only in simple split frctures my we ttempt rthroscopic control. With these considertions in mind, Krettek et l [3] strted to comine the principle of ORIF for the rticulr segment in complex distl femorl frcture with minimlly invsive, sumusculr tunneling long the diphysis for the insertion of long ridging plte. The introduction of the less invsive stiliztion system (LISS) for distl femorl (chpter 6.6.3) nd proximl tiil frctures (chpter 6.8.1) opened new possiilities for minimlly invsive plte osteosynthesis (MIPO). First clinicl results in different series [4, 5] seem to show definite iologicl dvntges of minimlly invsive pproches tht pper to enhnce frcture heling nd reduce the risk of infection. MIPO procedures with sumusculr plting hve een shown to preserve periostel lood supply when the internl fixtor principle using locking hed screws (LHS) is pplied correctly (LISS nd LCP system) (chpter 3.3.4) [6]. The short self-drilling nd self-tpping LHS cn e inserted through st incisions using specil protection sleeves. 2 Definition of minimlly invsive osteosynthesis (MIO) Minimlly invsive osteosynthesis (MIO) includes ll forms of frcture fixtion tht use smll soft-tissue windows which llow insertion of implnts or instruments; cuse miniml dditionl trum to the soft tissue nd frcture frgments; use indirect (trction tle, externl fixtor, distrctors, mnul trction), or gentle direct reduction techniques (K-wires, reduction screws, percutneous reduction forceps, joysticks); cn pply the iomechnicl concepts of reltive stility or, exceptionlly, solute stility [7]. By this definition, MIO includes ll types of percutneous frcture fixtion such s externl fixtion, closed intrmedullry niling, percutneous K-wire or screw fixtion s well s minimlly invsive plte osteosynthesis (MIPO). In this chpter MIPO is covered, while other minimlly invsive techniques cn e found elsewhere (intrmedullry niling (chpter 3.3.1), externl fixtor (chpter 3.3.3), internl fixtor (chpter 3.3.4), percutneous K-wire or screw fixtion (chpter 3.2.1)). 199

2 3 Reduction, pproches, nd fixtion techniques 3.1 Reduction nd pproches 3 Indictions for minimlly invsive plte osteosynthesis (MIPO) The option for minimlly invsive plte ppliction must lwys e lnced ginst other possiilities, especilly intrmedullry niling. Both hve similr iologicl dvntges over conventionl ORIF nd require creful preopertive plnning. MIPO is used in epi-/metphysel frctures; when soft-tissue conditions preclude n open procedure; when frcture pttern is not suitle for intrmedullry niling (intrrticulr extension, nrrow, deformed or ostructed medullry cnl); when other implnts hve lredy een used (eg, rthroplsty); when still open growth pltes re involved in frcture; when n imge intensifier is not ville; when the ptient s generl condition (eg, polytrum, lung contusion) precludes dditionl systemic insult, eg, y medullry reming. Plte osteosynthesis must provide the correct iomechnicl environment for specific frcture pttern. For exmple, plting of simple metphysel frcture should lwys e y interfrgmentry compression providing solute stility, which cn often e comined with minimlly invsive techniques. However, this principle should not e neglected in fvor of smller skin incisions. 4 Preopertive plnning for MIPO Preopertive plnning is of prmount importnce with MIPO techniques. 4.1 Wht does plnning include? Plnning should consider ll steps of the procedure nd therefore include the pproprite pproches, reduction techniques, instruments, nd implnts. Before performing MIPO, severl questions must e sked: Where re the ntomicl dnger zones? How cn reduction e chieved nd lso mintined? Should the fixtion provide reltive stility y ridge plting, or solute stility y interfrgmentry compression? Are ll the instruments nd implnts ville? Is the C-rm ville? Is there need for dditionl instruments to fcilitte percutneous reduction? Is there need for contouring of the plte? When is ORIF indicted if the originl gol of MIPO cnnot e chieved? 4.2 Dnger zones A thorough knowledge of surgicl ntomy is necessry to void dmging vitl structures, such s nerves nd lood vessels. It is essentil to know the cross-sectionl ntomy for the pssge of pins nd wires (eg, circulr externl fixtor) s well s the course of vessels nd nerves for sumusculr insertion of pltes nd percutneous insertion of screws. 200

3 3.1.3 Minimlly invsive surgery 4.3 Reduction Tools Indirect reduction should generlly e plnned prior to implnt ppliction. Indirect reduction y trction cn e performed mnully, with trction tle, with distrctors or externl fixtors, or directly y Schnz screws. Specil instruments hve een developed for direct reduction techniques such s mnipultors pplied to Schnz screws, or the coliner reduction forceps (Fig ) (chpter 3.1.1). Mintining reduction Once reduction hs een otined, it should e mintined temporrily for imging nd until the pproprite plte nd screws hve een inserted c d Fig d Coliner reduction forceps for minimlly invsive percutneous reduction of frctures used on periprosthetic frcture of the femorl shft. Reduction forceps with different tips for MIPO of shft frctures (1), pelvic frctures (2), nd rticulr frctures (3). c d Reduction forceps in situ. Frcture reduction with the coliner reduction forceps in periprosthetic frcture. Appliction of the reduction forceps fter reduction nd percutneous insertion of plte. 201

4 3 Reduction, pproches, nd fixtion techniques 3.1 Reduction nd pproches 4.4 Asolute or reltive stility? For most MIPO techniques reltive stility is generlly recommended. However, in simple metphysel type A frctures ntomicl reduction nd solute stility with interfrgmentry compression is recommended to reduce the strin in the gp nd to permit direct frcture heling. Asolute stility is lso mndtory for frctures involving the rticulr segment. However, in complex met-/diphysel frctures, reltive stility with long ridging plte is usully dequte for the lignment nd pproximtion of intermedite frgments. 4.6 Alterntive pln There should lwys e n lterntive pln in cse MIPO cnnot e crried out s desired. It should include: miniml opening of the frcture site to pply n instrument for direct reduction; exposing the frcture s in conventionl plting; chnging to intrmedullry niling or externl fixtion; sking for help from more experienced surgeons. 4.5 Implnts Animtion Conventionl pltes (LC-DCP) Conventionl pltes should e very long (10 14 holes in the tii nd humerus, holes in the femur). A generl rule is tht the plte should e t lest three times the length of the frcture zone, often reching from one metphysis to the other. Exct contouring of the plte, especilly t either end, is required in order to prevent secondry displcements (ngultion nd rottion). A plstic one model my help to contour the plte preopertively. Locking pltes (LISS/LCP) Thnks to the locking hed screws (LHS) these implnts, if used s internl fixtors, do not require s precise contouring s conventionl pltes (Fig Animtion ), ecuse the implnt is not pressed ginst the one nd there will e no loss of reduction. However, miniml contouring of one plte end my e dvisle to prevent prominence of the plte under the skin (chpter 3.3.4). Contouring of the LCP should not occur within the threded holes s deformtion my reduce firm purchse of the locking hed screw. Fig Animtion With conventionl screws the one is reduced (pulled) towrds the plte. Angulr stility of the locking hed screws ensures mintennce of initil reduction even if the plte is not contoured exctly. This llows the LCP to e inserted y MIPO technique. 202

5 3.1.3 Minimlly invsive surgery A thorough knowledge of the different pros nd cons of MIPO will help to reduce pitflls ssocited with this kind of surgery such s mlreduction, implnt filure, mlunion, delyed union, nd nonunion [8]. 4.7 Intropertive imging The imge intensifier is n essentil piece of equipment for ll MIO procedures. The view should e dequte (9- or 12-inch screen) to get s lrge picture s possile for the ssessment of xil lignment. The position of the C-rm is criticl in order to chieve orthogonl views during surgery, nd should e tested efore scruing. MIPO crries the risk of prolonged use of the imge intensifier. For distl femorl frctures rdition time during surgery verged 5.4 minutes in multicenter study, including the lerning curve [5]. Reduction tools like joysticks with T-hndles or the lrge femorl distrctor [7, 9] re helpful for reduction nd mintining reduction during rdiologicl ssessment nd implnt insertion. Computer nvigtion hs the potentil to further reduce exposure to rdition. 5.2 Femur The whole length of the femur is menle to MIPO on the lterl side. There is excellent soft-tissue coverge nd no importnt neurovsculr structure is locted in this prt of the surgicl field. Screw insertion through st incisions my e possile, ut in oese or musculr ptients 2 4 cm incision t the end of the plte is recommended to ensure ccurte positioning of the implnt in reltion to the one Femur, proximl (chpter 6.6.1) Percutneous insertion of 7.3 mm cnnulted lg screws is common technique for the stiliztion of minimlly displced sucpitl frctures (31-B1). The sideplte of the dynmic hip screw cn e inserted percutneously for the tretment of intertrochnteric frctures (31-A). MIPO hs lso een descried for the insertion of 95 ngled lde plte (Fig ) or dynmic condylr screw (DCS) for the tretment of sutrochnteric frctures. The procedure requires some experience nd is est tried out on cdveric specimen. 5 MIPO in specific one segments 5.1 Humerus (chpter 6.2.1; 6.2.2) MIPO hs een used for frctures of the proximl humerus nd humerl shft. However, the xillry nd rdil nerves re situted close to the one nd my e t risk with these procedures. MIPO is currently eing evluted for the humerus nd should only e pplied y surgeons with expertise in MIPO techniques. Fig MIPO for proximl femur nd shft frcture with 95 ngled lde plte. 203

6 3 Reduction, pproches, nd fixtion techniques 3.1 Reduction nd pproches Femur, shft (chpter 6.6.2) Most femorl shft frctures re treted with n intrmedullry nil. However, plte fixtion my e considered in frctures tht extend into the proximl or distl metphysis, in dolescents with n open proximl growth plte, in polytrum ptients, or when n ssocited frcture precludes intrmedullry niling (eg, cetulr or displced femorl neck frcture). The long epiperiostel elevtor is very useful for creting sumusculr tunnel without stripping the periosteum. The plte cn e introduced from either proximl or distl, depending upon the frcture pttern nd preopertive pln (Fig ). Fig MIPO for femorl shft frcture, using n epiperiostel elevtor for plte ed preprtion. LCP with plte holder to help insertion of the plte Femur, distl (chpter 6.6.3) Extrrticulr distl femorl frctures re good indiction for MIPO with the LISS-DF or LISS-LCP s n lterntive to the retrogrde intrmedullry nil. Displced rticulr frctures require ntomicl reduction, which in turn will usully necessitte ORIF of the joint lock. However, the lterl plte cn e inserted with MIPO techniques nd through sumusculr tunnel (Fig ). 5.3 Tii Fig MIPO in distl femorl frcture, using the LISS-DF. The entire length of the tii is menle to MIPO y lterl s well s medil pproch. The medil spect of the one lies sucutneously, which mkes the insertion of pltes techniclly esy. However, the sence of muscle cover mens tht the plte my compromise soft-tissue heling nd the implnt my e prominent underneth the skin. Lterlly inserted pltes will e covered y muscle, which mkes them sfer for soft- tissue heling, ut they re more difficult to contour nd pply. The mjor neurovsculr structures re outside the surgicl field with either pproch, ut the surgeon must e wre of the gret sphenous vein nd nerve medilly, nd the nterior tiil neurovsculr undle in the distl third of the tii nd the superficil fiulr nerve lterlly. 204

7 3.1.3 Minimlly invsive surgery to reduce the exposure. Complex frctures will require ridging technique, while simple frcture ptterns require ntomicl reduction nd solute stility if plte is used. With creful plnning nd skilled ppliction, this cn e chieved y MIPO techniques (Fig ) Tii, distl (chpter 6.8.3) The following text descries n exmple of MIPO (Fig ) in the distl tii. Fig MIPO using LCP for complex distl tiil frcture. Open reduction of the joint surfce ws performed through smll nterolterl incision. Cse The frcture pttern nd its loction in the distl metphysis is n indiction for MIO. An intrmedullry nil ws not considered ecuse the distl interlocking screws would e lying in the frcture zone resulting in indequte fixtion of the distl frgment. Bridge plting ws chosen due to the complex frcture pttern Tii, proximl (chpter 6.8.1) Lterl tiil plteu frctures cn e treted with sumusculrly inserted plte. Open reduction of the joint is usully necessry. Medil plteu frctures re treted in similr mnner. Bicondylr frctures with complex metphysel injuries often require two pltes, nd MIPO in these cses is very useful for the introduction of posteromedil uttress plte. MIPO reduces the prolems ssocited with doule plting through single incision. Arthroscopy my e used to confirm intrrticulr reduction nd to ensure tht implnts do not protrude into the joint Tii, shft (chpter 6.8.2) Tiil shft frctures extending either into the knee or nkle joint my require plte fixtion. MIPO my e dvntgeous Approch The surgicl pproch should lwys consider the possiility of switching to n open procedure if indirect reduction cnnot e otined nd mintined. Therefore slightly curved incision over the medil mlleolus is recommended s it my e extended into stndrd open pproch to the distl tii. Dngers The sphenous vein nd nerve must e identified nd gentle sucutneous tunneling should e performed with n epiperiostel elevtor (Fig ). Options for reduction Mnul trction: Pros: It is esy to pply, nd its flexiility llows mneuvers in ny direction. Cons: Rdiologicl ssessment is not possile without exposing the surgeon s hnds to rdition. 205

8 3 Reduction, pproches, nd fixtion techniques 3.1 Reduction nd pproches c d e f Fig f Closed distl tiil frcture 42-B1.3. c d A LCP ridge plting procedure ws selected to otin correct xil lignment for this complex frcture pttern. After plte insertion, s first step, the two 4.5 mm lg screws were plced through the plte into the wedge frgment. Next two LHS were pplied on either side. Note the clips t the level of the skin incisions, which indicte the extent of the incisions. e f X-ry fter 1 yer. c Fig c Epiperiostel preprtion of the plte ed. The gret sphenous vein nd nerve is protected (ruer sling) throughout the procedure. Insertion of the plte. c Epiperiostel elevtors. 206

9 3.1.3 Minimlly invsive surgery Externl fixtor (different frmes, eg, tue-to-tue connection): Pros: Esy ppliction nd retention of reduction for rdiologicl control nd plte insertion. Cons: The lrger the distnce etween the pins, the more difficult it is to otin effective distrction nd to reduce the frgments. Lrge distrctor, eg, joint ridging etween tii nd clcneus: Pros: This llows distrction when shortening is prolem (delyed cse) nd mintins reduction for x-ry control. Cons: Rottion is less esy to correct nd joint ridging my result in lot of strin on the joint cpsule. Reduction with the help of plte: Pros: A precontoured plte is inserted sucutneously nd medilly. Thnks to the intct nd tight soft-tissue sleeve the plte tends to lign the frcture nd cts s splint. When using conventionl LC-DCP exct plte contouring is mndtory to prevent ny loss of reduction when the plte is fixed (pressed) ginst the one (Fig Animtion ). Furthermore, the order of screw insertion is essentil nd must e crefully plnned. Loss of reduction is generlly not prolem when LCP with LHS is used, ecuse the plte does not distur the lignment when LHS re tightened. Cons: Reduction depends upon precise contouring of LC-DCP. If the techniques of closed indirect reduction descried ove re not successful, dditionl mneuvers my e necessry, such s: Reduction tools pplied close to the frcture, eg, K-wires, Schnz screws, pushers, or even digitl pressure: Pros: Direct force is pplied where necessry. Cons: Additionl soft-tissue incisions need to e mde close to the frcture. Percutneous pointed reduction forceps (Fig ): Pros: Direct reduction of the frcture is performed similr to n ORIF procedure, with ner perfect results in simple frctures. Cons: Additionl skin incisions close to the frcture focus re needed, which cn further dmge vsculrity. Percutneous reduction screw (definition: T ): Pros: In cse of ridging plte nd reltive stility reduction screw helps to pproximte wide frcture gp or to ring utterfly frgment closer to the min frgments without interfrgmentry compression. Position screws cn then e inserted through the plte or independently. Cons: There my e tenuous periostel connections to utterfly frgments, which could e stripped s the rotting drill or screw engges the frgment. These mneuvers cn e improved y using specil MIPO tools which re designed to minimize trum to soft-tissues nd one. 207

10 3 Reduction, pproches, nd fixtion techniques 3.1 Reduction nd pproches Fig c Distl tiil shft frcture treted with MIPO using LCP. Antomicl reduction with percutneous forceps () nd ppliction of lg screw (); the LCP serves s protection plte. Postopertive x-rys, AP nd lterl (c). c Switching to limited ORIF In cse closed reduction hs not een successful, gentle open reduction through smll incision should e considered. This possiility must e included in the preopertive pln, especilly when deling with delyed surgery, nd helps to void frustrting ttempts with prolonged exposure to rdition nd unnecessry soft-tissue dmge round the frcture site. Pitflls In simple frcture ptterns pure ridge plting is not recommended since delyed union my result if the frcture gp remins too wide (> 2 mm), or if the internl fixtor is too stiff ecuse ll plte holes hve een filled with screws. In oth cses implnt filure due to ftigue or stress concentrtion t the level of the frcture my result (Fig Animtion ). Mlreduction, especilly mlrottion, my e hrd to check with MIPO s the imge intensifier gives only limited view of the xis. Intropertive comprison with the seprtely drped, uninjured leg helps to prevent this. The methods for ssessing rottionl mllignment re well documented in chpter Postopertive tretment Postopertive tretment of frctures stilized with MIPO follows the sme principles s fter conventionl plting. Prtil weight ering (15 30 kg) is recommended for 6 10 weeks, depending on the frcture pttern, the stility of fixtion, the complince of the ptient, nd the ppernce of visile frcture ridging cllus. Full weight ering my e encourged when the x-ry nd clinicl signs of frcture heling show consolidtion. 208

11 3.1.3 Minimlly invsive surgery Stress distriution Stress concentrtion Animtion Fig Animtion Stress distriution. Influence of screw fixtion on forces within the plte. 6 Complictions Skin rekdown Skin rekdown nd superficil infection my occur when too much tension hs een pplied during surgery with retrctors, respectively for the closure of the incision with hevy sutures. Deep infection Compred to conventionl open procedures, infection rtes fter MIO hve een reported to e lower [4], even in cses of severe open frctures. Mlunion The difficulty of ssessing correct xil nd rottionl lignment y imge intensifiction my result in more cses of mlreduction thn with ORIF (6 34%) [4, 5, 10 12]. Indirect reduction techniques need to e prcticed, nd percutneous ppliction of specil instruments for reduction must e very gentle. When using n internl fixtor with locking hed screws, the frcture should e reduced nd correctly ligned prior to plte ppliction ecuse the plte will not ssist the reduction. This chnge of concept from conventionl to locked plting is proly the most common cuse of mistkes in MIPO. Delyed union/nonunion Nonunion is uncommon following MIPO, provided the principles of internl fixtion re followed. In high-velocity frctures, the necessity for secondry intervention (one grfting) is etween 2.5 7% [4, 5]. If there is miniml cllus formtion t 6 8 weeks, one must wtch the sitution crefully nd proceed to one grfting t n erly stge in order to void implnt filure. Implnt filure Plte rekge fter MIPO hs een descried in cses of delyed union (sence of cllus formtion) [5, 7, 8, 13]. This my e due to distrction, frcture gp wider thn 2 mm, highenergy impct with soft-tissue injury nd devsculriztion of the one frgments, or filure to chieve solute stility in simple frcture ptterns. 209

12 3 Reduction, pproches, nd fixtion techniques 3.1 Reduction nd pproches 8 Conclusion Fig Plte position hs to e centered on the shft to void tngentil screw plcement, which is ssocited with loss of fixtion. Knowledge of frcture fixtion hs evolved rpidly in recent yers. Where possile, the im of surgery is to chieve iologicl fixtion through tissue-preserving pproches. While this ide hs een rpidly dopted throughout the world, cler concepts of the principles nd proper performing of techniques of minimlly invsive osteosynthesis remin prolem mong surgeons. This chpter hs outlined the steps required to perform minimlly invsive surgery/minimlly invsive plte osteosynthesis with emphsis on sfe nd logicl pproch. Loss of purchse fter percutneous insertion hs een oserved with the LISS, when very long pltes were used nd the correct plcement of the proximl end of the plte reltive to the one ws not checked. This my result in tngentil screw plcement (Fig ), which my go unnoticed s the locking hed screws lwys pper to hve good purchse in the threded hole. 7 Implnt removl Implnt removl fter MIO my e more difficult thn implnt insertion. As swelling susides, incisions re often no longer in their originl position reltive to screw. While specil instruments nd drill its my e required to fcilitte plte removl fter MIPO, direct pproch should e tken to remove individul screws. This is of specil relevnce when using titnium locking hed screws tht my e firmly locked in the plte if they hd not een inserted properly with the torque-limiting screw driver [14]. 9 Biliogrphy [1] Kinst C, Bolhofner BR, Mst JW, et l (1989) Sutrochnteric frctures of the femur. Results of tretment with the 95 degrees condylr lde-plte. Clin Orthop Relt Res; (238): [2] Mst J, Jko R, Gnz R (1989) Plnning nd Reduction Technique in Frcture Surgery. 1st ed. Berlin Heidelerg New York: Springer-Verlg. [3] Krettek C, Schndelmier P, Tscherne H (1996) [Distl femorl frctures. Trnsrticulr reconstruction, percutneous plte osteosynthesis nd retrogrde niling.] Unfllchirurg; 99(1):2 10. [4] Kregor PJ, Stnnrd JA, Zlowodzki M, et l (2004) Tretment of distl femur frctures using the less invsive stiliztion system: surgicl experience nd erly clinicl results in 103 frctures. J Orthop Trum; 18(8): [5] Schütz M, Muller M, Regzzoni P, et l (2005) Use of the Less Invsive Stiliztion System (LISS) in ptients with distl femorl (AO33) frctures: prospective multicenter study. Arch Orthop Trum Surg; 125(2): [6] Frouk O, Krettek C, Miclu T, et l (1997) Minimlly invsive plte osteosynthesis nd vsculrity: preliminry results of cdver injection study. Injury; 28(Suppl 1):7 12. [7] Bst R, Hehli M, Regzzoni P (2001) [LISS trctor. Comintion of the less invsive stiliztion system (LISS) with the AO distrctor for distl femur nd proximl tiil frctures.] Unfllchirurg; 104(6):

13 3.1.3 Minimlly invsive surgery [8] Sommer C, Bst R, Muller M, et l (2004) Locking compression plte loosening nd plte rekge: report of four cses. J Orthop Trum; 18(8): [9] Hk DJ, Stewrt RL, Lee M (2004) Preliminry stiliztion of the less invsive stiliztion system. J Orthop Trum; 18(8): [10] Ricci WM, Rudzki JR, Borrelli J Jr (2004) Tretment of complex proximl tii frctures with the less invsive skeletl stiliztion system. J Orthop Trum; 18(8): [11] Cole PA, Zlowodzki M, Kregor PJ (2004) Tretment of proximl tii frctures using the less invsive stiliztion system: surgicl experience nd erly clinicl results in 77 frctures. J Orthop Trum; 18(8): [12] Stnnrd JP, Wilson TC, Volgs DA (2004) The less invsive stiliztion system in the tretment of complex frctures of the tiil plteu: short-term results. J Orthop Trum; 18(8): [13] Button G, Wolinsky P, Hk D (2004) Filure of less invsive stiliztion system pltes in the distl femur: report of four cses. J Orthop Trum; 18(8): [14] Georgidis GM, Gove NK, Smith AD, et l (2004) Removl of the less invsive stiliztion system. J Orthop Trum; 18(8):