principii amputatii

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Introduction and General Principles

Robert G. Atnip, MD

The feet and toes are surely among the most abused andleast appreciated regions of the human anatomy. There

are few structures in the body, indeed, even fewer man-madedevices or appliances, that are subjected to such intense re-petitive, relentless punishment in such an unforgiving envi-ronment, yet expected to perform without flaws. Though notthe only animal species capable of mobility on two feet, thehuman is, nonetheless, the only species that is exclusivelybipedal and cannot fly. With human girth and mass showingunprecedented increases of heretofore unimagined demo-

graphic proportions, it appears that the human foot will betested in the future more than it has ever been tested in thepast.

Only those with bad feet can truly appreciate the bliss of having good feet. Yet bad feet and good feet alike are seldomafforded the attention and respect that should be their due.The good foot is expected to support a mass 200 to 300 timesits own, on a surface area no more than 1% of the body as awhole, with such assumed performance and durability thatits owner will likely give it no conscious regard. The bad footis expected to heal quickly and completely, and preferablywhile still in use. The inconvenience of a bad foot is onewhich most persons tolerate poorly and with great impa-

tience. But rather than inspiring awe and reverence for themiracles that the foot routinely performs, such temporarydisabilities more often provoke vexation and resentment atthe unwelcome interruption of mobility. So the host forceshis foot to function while dysfunctional, to heal while un-healthy, and to again withstand the trauma and neglect thatcaused the original problem. It is the fate of the feet and toesto be taken for granted until catastrophe ensues, and evenbeyond.

Advances in modern podiatry, plastic surgery, orthope-dics, andvascular surgery offer hope and relief for themyriadproblems that beset the modern foot. Most such problemscan either be prevented, or alleviated with orthotic appli-ances, or corrected with relatively minor surgery. Indeed,many body parts, including the hips and knees, are ulti-mately more likely than the foot to fail and require majorsurgery. Unlike those structures, however, the foot cannot be

replaced. Irreversible disease or injury of the toes and feetleads to amputation. Amputation surgery itself has advanced

in modern times, though perhaps not as dramatically as thescience of prosthetics. Fortunately, the end result for mostpatients is a return to functional ambulation.1,2

The articles and illustrations in this journal present theessential considerations and techniques for successful lowerextremity amputation, whether of a single toe or of the entirelimb. The methods depicted herein represent standard and

widely employed techniques for amputation surgery. As with

any surgical procedure, individual surgeons will modify theirtechnique as necessary to achieve optimal outcomes for eachindividual patient.

Factors Leading to Amputation

Patients presenting for consideration of toe or partial footamputation typically have some combination of injury, ulcer-ation, tissue necrosis, and infection. A variety of conditionsand factors exist that predispose to the occurrence of limb-threatening tissue loss in the foot. In patients with diabetes

mellitus, the processes of infection, ischemia, and neuropa-thy have been expressed as a combined “classic triad” of riskfactors, and many similar groupings could be proposed fordiabetics and nondiabetics alike. An alternate and helpfulway of organizing these many influences is to segregate theminto local and systemic categories.

Local FactorsNumerous inherent characteristics of the foot itself are re-sponsible for its vulnerability to injury and infection. Thevery purposes of the foot are to bear the weight of the bodyand provide mobility, and the design of the foot is specific for

those purposes. The bony architecture provides surfaces thattolerate high pressures by spreading them over as much area

as possible, while allowing the flexibility needed for all vari-eties of locomotion. Some loss of that architecture can betolerated, but more so on the dorsal surface than the plantar.Deformities that cause pressure points on the plantar surfaceare the cause of much dysfunction, disability, and limb loss.On the dorsal surface, weight bearing is less of an issue, butan equally serious problem is the thinness of theskin andsofttissue and relative lack of protection of the underlying ten-dons, muscles, and joints. Full-thickness skin loss on thedorsal surface can result in exposure and dessication of theunderlying fascia and tendons, often with few reconstructive

Penn State Hershey Medical Center, College of Medicine of thePennsylvania

State University, 500 University Drive, Hershey, PA.

Address reprint requests to Dr. Robert G. Atnip, Professor of Surgery and

Radiology, Chief of Vascular Surgery, Penn State Hershey Medical Cen-

ter, College of Medicine of the Pennsylvania State University, 500 Uni-

versity Drive, Hershey PA 17033-2390. E-mail: [email protected]

62 1524-153X/05/$-see front matter © 2005 Elsevier Inc. All rights reserved.

doi:10.1053/j.optechgensurg.2005.07.001



options. Similar problems occur when ulcers develop over joints on the dorsum of the toes or sides of the foot.

Although well padded on the plantar aspect, the calcaneusis famously vulnerable on its posterior surface where softtissuecoverage is much thinner. Decubitusulcerations in thisarea are typically full thickness, often down to the calcaneal

bone itself, and highly resistant to healing unless pressurerelief and optimal perfusion can be achieved.In many patients, especially diabetics, limb loss is initiated

by seemingly trivial lesions on the toes. Ill-fitting footwear,nail care accidents, and other minor trauma are the mostcommon causes, often in the setting of sensory loss and bonydeformity from diabetic polyneuropathy. Chronic fungal anddermatophyte infections of the toes can act alone or withother factors to trigger local skin injury and subsequent ne-crotizing infections.

Patients and their physicians are equally culpable in failingto recognize minor foot problems, and in failing to treat themaggressively in the early reversible stages. Though personswith normally innervated feet areexquisitely sensitive to pain

and pressure, those with neuropathic feet may be completelyunaware of even theworst noxious stimuli unlessthe injury isdetected visually. Even when blisters, ulcers, lacerations,paronychiae and other warning signs are noticed and re-ported, all too many physicians do not recognize these smalllesions forthe great havoc that they can wreak, particularly inthe presence of ischemia and systemic disease.

Systemic FactorsDiabetes mellitus is unquestionably the dominant systemiccause of major limb loss in adults. The risk of limb loss inpatients with this disease is many fold higher than in compa-rable nondiabetic populations, owing to effects such as im-munosuppression, neuropathy, and accelerated vascular dis-ease. Ischemia and neuropathy have a greater incidence inthe lower extremity compared with other anatomic regions,andclearly actin concert with local factors to promote injury,infection, and necrosis of the foot and toes. Much remainsunknown regarding specific mechanisms of interaction be-tween this disease and its host, perhaps in part because dia-betes is not a single disease entity. Much attention has beenfocused on the question of whether complications of diabetescan be avoided or ameliorated by better glucose control. Yeteven with dramatic progress toward understanding diabetes,key questions remain unanswered and key misconceptionspersist, especially as concerns the interplay of diabetes and

peripheral vascular disease.In the classic triad of infection, neuropathy, and ischemia,

the latter entity may well be the least understood. The gaps inknowledge begin at the level of basic science, but are perva-sive in the clinical realm, where the difficulty lies not nearlyso much in a failure to know as in a failure to recognize andapply that which is known. Although reconstructible athero-sclerosis of the named axial arteries of the lower extremity isthe primary cause of ischemia in diabetics and nondiabeticsalike, a well-entrenched fallacy still circulates, even amongexperienced clinicians, that nonreconstructible “small vesseldisease” of thefoot is equally prevalent. Such a misperceptionunderlies a false belief that ischemia is untreatable, which in

turn allows it to go undiagnosed. In fact, the number of

effective treatment options for peripheral arterial disease hasnever been greater, but there is much progress to be made inmaking treatment available to those with limb-threateningischemia in time to prevent major tissue loss.

Other systemic factors that target the foot and toes arebecoming increasingly prevalent. Though not widely dis-

cussedin this particular context, obesity cannot be ignored asa disease whose wide-reaching effects certainly include enor-mous stress on feet that must support hundreds of pounds of excess body mass. Obesity leads to increased trauma to thefeet, and promotes lipid disorders, hypertension and diabe-tes. Obese patients are often physically unable to performadequate skin and nail care of the feet, and can developsubstantial edema due to venous or lymphatic insufficiency.Obese patients pose daunting technical challenges for arterialreconstructive surgery, but fare even worse with limb loss.

Finally, and in addition to the immunosuppression asso-ciated with diabetes, there are numerous pharmacologicagents that inhibit the immune system and thereby enhanceother processes that lead to skin breakdown and infection in

the feet. Corticosteroids, cyclosporin, methotrexate, plaque-nil, and newer immune-targeted drugs not only lower resis-tance to infection but may also impair tissue integrity, inhibithealing, and even promote accelerated atherosclerosis.

General Principlesof Amputation

The desired end results of amputation are complete healing,and restoration of function. An amputation is a reconstruc-tive procedure, and as such requires precise and exactingtechnique. For most patients, there will be no second chancefor healing, short of a second higher amputation, an outcome

both physically draining and emotionally devastating. Pa-tients facing limb loss arekeenly aware of this possibility, andoften fear it more than the primary procedure itself. Re-am-putation can never be entirely prevented or avoided, and itslikelihood can only be minimized by the most rigorous sur-gical judgment and technique.

The Decision to Amputate Although generally viewed as the “last resort,” amputation is,like all surgical procedures, one that will turn out best for thepatient if it is done for the right patient and the right reason atthe right time. Amputation must never be viewed as a defaultprocedure that is employed only after all other options have

been explored. Such a perception fails to recognize the re-constructive nature of amputation surgery, and thus resultsin grave disservice to the patient. Amputation must be amongthe options considered by any clinician, medical and surgicalalike, called to treat the patient with serious infection, ulcer-ation, ischemia, or injury of the lower extremity. In selectedcases, amputation should be the primary procedure. In allothers, the possibility of amputation should be incorporatedearly into the physician’s thinking, to ensure that the chosentreatment regimen does not needlessly compromise thechance of successful amputation should the need arise.

Amputation is generally indicated to control refractory in-fections, or to treat pathology of the foot that is either irre-

versible or so far advanced that healing of a functional foot is

Introduction and general principles 63



not feasible. Amputation is usually an elective procedure, butmay become urgent in cases of aggressive local sepsis, espe-cially if accompanied by systemic toxicity. In such cases, thepatient may require open or guillotine amputation to limitthe spread of infection or to avert life-threatening sepsis. Thelevel and extent of amputation in these circumstances will be

dictated by both local and systemic factors, but must be cho-sen to ensureswift and effective reversal of the septic process.Thorough drainage of deep space infections and debride-ment of wet gangrene are essential to halt propagation of theinfection. Aggressive initial surgery in these patients will usu-ally preserve ultimate limb length and function rather thancompromise them.

In the more typical elective amputation, the surgeon’s goalis to select the level of amputation that will optimize bothhealing and function, with the recognition that in most cases,these dual requirements are at cross purposes. In the pres-ence of normal perfusion to the foot, the patient will, as arule, obtain optimal function from an amputation that sparesas much length andtissue as is technically possible. Contrari-

wise, in the face of trauma, ischemia, or any other circum-stance that compromises tissue perfusion, the surgeon mustface a fundamental dilemma: the chance of healing and thechance of function vary inversely with one another. Perfusionand healing improve with higher amputations, while func-tion will steadily decline. In each such patient, therefore, thesurgeon will need to carefully analyze the arterial flow to thelimb, optimize it however possible, and then essentially pri-oritize between function and healing. Factors to be consid-ered in this process include a detailed knowledge of the pa-tient’s psychosocial history, past and current functionalstatus, general medical condition, rehabilitation potential,and an objective assessment of the healing potential of the

selected amputation level(s).Much has been written about choice of amputation level,butas yet, no specific tool or technology hasproven any moreaccurate than the combination of physical examination andbedside Doppler. Basic surgical principles dictate that ampu-tations are not likely to heal if performed through or nearzones of active cellulitis, suppuration, severe ischemia, orfrank necrosis. The severity of all these conditions can typi-cally be determined by careful physical examination. In thecase of ischemia, however, additional useful information canbe obtained with a portable continuous-wave Doppler, sup-plementedif necessary by simplenoninvasive testing, such asphotoplethysmography (PPG) and transcutaneous oximetry(TCpO2). Other more sophisticated studies such as laser

Doppler velocimetry and Xenon perfusion are much lesswidely used, and do not appear to offer any greater accuracyof prediction.3

Bedside doppler examination includes quantitative (anklesystolic pressure, ASP) and qualitative (signal quality) infor-mation, which both complement and objectify the basic pal-pation of femoral, popliteal, and pedal pulses. A manualpulse examination is essential, and can be surprisingly accu-rate in predicting healing. At any chosen level, the presenceof a palpable pulse at the nearest proximal joint is associatedwith healing rates of 90% or higher, whereas those rates dropsignificantly if pulses are palpable only at two or more jointsremoved from theselected site. Studies have differed as to the

exact relationship between ankle pressure (or ankle-brachial

index, ABI) and the success of healing, but most surgeonswould attempt a toeor partial foot amputation in a nondiabeticif the ASP were greater than 80 mm Hg, and there were noother contraindications. As ASP is often inaccurate or notmeasurable in diabetics with calcified tibial arteries, the cli-nician will often find toe systolic pressures or PPGs more

helpful. Toe pressures greater than 40 mm Hg correlate withimproved healing, as do pulsatile PPG tracings. The useful-ness of transcutaneous oximetry is debatable, due to a ratherwide range of indeterminate values.

The possibility of limb amputation should enter early intothe thinking of those caring for the patient with a threatenedlimb, but should only be enacted after the most thoughtfuland deliberate analysis, a process which must include thepatient and family. Uncertainty of outcome is a given. In thatcontext, however, the surgeon’s efforts to ensure healing andpreserve function must be based on as much objective infor-mation as possible, and on the exercise of consummate judg-ment and technical skill.

General Technical Principles

General Amputation surgery has never been and is not likely to be-come a popular pursuit among surgeons of any specialty. It isneither especially challenging nor sophisticated, and doesnot require advanced technology. In the era of advancedendoscopic surgery, complex endovascular intervention,

joint replacement, and nearly miraculous plastic reconstruc-tive surgery, amputation surgery seems to have changed littlesince the 19th century. It is no exaggeration to argue that thepersisting stereotype of major limb amputation is that of theCivil War battlefield.4 Amputation surgery is distasteful and

disturbing to many physicians (and quite a few surgeons),and is abhorrent for most persons to contemplate. Yet, whendone successfully and well, amputation is not just recon-structive, but also redemptive, capable of transforming recal-citrant suffering and incapacitation into healing and rehabil-itation, albeit, at a great and nonrefundable cost. To thisendeavor, the surgeon must apply every skill at his or herdisposal.

In performing an amputation, the surgeon must transect,ablate, cauterize, and sever, often with large instruments andbold strokes. But in the same procedure, the surgeon mustdebride, smooth, sculpt and re-shape, with movements bothprecise anddelicate. It is essential not only to possess each setof skills, but to know when each is needed. Whether a step in

the procedure calls for strength or subtlety, every sequence of action must be performedwith control andclearintention. Inamputations,as in many types of surgery, there is a high pricefor haste and carelessness. By long tradition, amputation sur-gery is often the first procedure performed by novice surgicaltrainees, but there is no better time than the beginning forthese young surgeons to learn under close supervision thatamputation requires no less skill and no less attention thanthe more advanced procedures they will learn later in train-ing.

Soft TissueThe single most important technical aspect of amputation (at

any level) is careful handling of tissue. Even the ablative

64 R.G. Atnip



aspects of the procedure must be done with as little injury tothe transected edges as possible. Virtually all patients who

require amputation have impaired tissue integrity, to whichis added the unavoidable injury of the amputation itself. Yet,

with appropriate technique, the degree and extent of injurycan be controlled. Proper use of the proper tools will enable

the surgeon to divide tissues cleanly, rather than tearing,breaking, avulsing, or crushing. Particular attention is neces-

sary to protect the skin edges from careless blunt or sharp

injury, which can lead to failure of primary healing. It isstrongly recommended to avoid use of forceps on the skin

edges at any time during an amputation.One of the more common technical and judgmental errors

in amputation surgery is attempted wound closure undertension, an error usually culminating in stump breakdown.

Avoiding this error requires forethought from the beginningof the case, and careful planning throughout. Flaps must be

designed to allow closure without tension. If there is seriousdoubt that this can be accomplished, the surgeon should

consider a different method, or even a more proximal ampu-

tation. Once committed, however, the surgeon should takewhatever additional time is necessary to sculpt the flaps and

successfully close them. Helpful maneuvers may include fur-ther shortening and recessing of bone stumps, and judicious

debulking of soft tissues, as long as blood supply is not com-promised.

BoneThe steps of dividing and shaping the bones must be handleddifferently in each amputation, but some general concepts

apply. Bones should be transected through the shaft, andamputations through joints should generally be avoided. Ar-

ticular cartilage receives its oxygen and nutrient supply fromthe synovial fluid, and is at high risk for necrosis if the artic-

ular surface is left intact within an amputation wound. Al-though this particular problem can be averted by removing

the exposed cartilage, an equally significant problem is thatbony articular prominences generally do not make good am-

putation stumps.Bones should be methodically stripped of their perios-

teum, and then transected cleanly with minimal splinteringand fragmentation. Any bone fragements and splinters mustbe removed from the wound. Bone edges should be meticu-

lously smoothed, especially in those areas that will lie closestto the skin. In some cases, beveling of the bone stump is

advisable to avoid sharp edges and pressure points, such ason the plantar surface of the foot. At every step, the surgeon

must be aware that orthopedic instruments (saws, drills, os-teotomes, rongeurs, etc.) have great capacity to damage ad-

jacent soft tissues if used carelessly.

Wound ClosureThe meticulous technique employed in the performance of an amputation must be carried through to placement of the

very last suture. Whether due to trauma, ischemia, local in-fection and inflammation, age, or other factors, the skin of an

amputation stump is seldom normal and healthy. Yet, thesuccess of the entire procedure often depends on that skin’s

ability to heal. Careless and indiscriminate handling of the

skin and soft tissues during closure can easily cause an oth-erwise successful amputation to fail.

The skin is, in fact, often the only tissue layer that can bereadily closed. When a digit or some part of the foot has beenamputated, the surgeon is typically confronted with one ormore bone stumps surrounded by transected joint capsule,

tendons, fascia, muscle, and subcutaneous fat. Depending onthe length of bone stump available, it may be possible torecess thestumpdeep enough to allow separate closure of thefascia or muscle over the bone. The advantages of deep clo-sure—coverage of bone and elimination of dead space—aresubstantial. Not infrequently, however, the level of resectionis such that the surgeon must be satisfied with a single layerskin closure, trusting that the deeper tissues will be coaptedby default.

Specific techniques for closure of the skin vary widely andare largely the province of personal preference. The authorfinds much to recommend in an interrupted nylon, eithersimple or vertical mattress, placed without use of forceps andreinforced by fine Steri-strips. Subcuticular closure or skin

staples arepopular in some quarters, although these methodsrequire more handling of the skin. Whatever method is used,the goal should be precise alignment and apposition of skinedges to create the best opportunity for primary healing.Failure of the skin and subcutaneous tissues to heal primarilyis an ominous development, usually resulting in wound de-hiscence and portending greater tissue loss.

The need may occasionally arise to place a wound drain inan amputation stump, but only if clearly indicated. Standardmeasures should be employed to obtain hemostasis, includ-ing direct pressure, judicious use of the electrocautery, topi-cal use of local anesthetics containing dilute epinephrine, andof course ligation of vessels. Even oozing wounds will usually

stop bleeding on re-approximation andclosure of the tissues,particularly if a bulky dressing is applied for added tampon-ade. If a drain is necessary, it should be inserted through aseparate stab wound, not through the suture line of thestump; it should be positioned to drain dependently, andshould be removed within 48 hours. Suction drains are pre-ferred to passive drains. A temporary vacuum dressing withdelayed primary closure may be considered in some circum-stances.

DressingsThe dressing of amputation stumps is often a matter of reli-gion more than science. Practitioners adopt their favorite

dressings through training and experience, and then adhereto them fervently. Dressings can be soft or rigid, small orlarge, occlusive or open. A good dressing will padand protectthe stump, inhibit seromas andhematomas, absorb drainage,immobilize joints, serve as a barrier to contamination, and inall these ways, generally promote healing. Any given type of dressing can succeed or fail to accomplish these goals de-pending on how it is applied. The most common and costlyerror in dressing technique is to wrap thedressing too tightly,resulting in pressure necrosis of the stump or adjacent areas,which at best will delay healing, and at worst may requirere-amputation. Areas at risk for this complication include thedorsum of the foot, the malleoli, the heel, and the patella.

Preventive measures include proper technique in applying

Introduction and general principles 65



the dressing, and early frequent dressing changes with skininspection, especially if the patient complains of more painthan expected.

Open amputation stumps are generally handled differentlyfrom closed stumps, with great variation in individual prac-tice. The method chosen may depend on whether the sur-

geon’s intention is for early revision, delayed primary closure,or secondary closure. The use of vacuum-assisted closuretechniques has become increasingly popular.

Postoperative ActivityPostoperative care routines are, again, very surgeon- and am-putation-specific. Patient positioning, allowed activity, com-mencement of physical therapy and weight bearing, use of antibiotics, and prophylaxis of deep vein thrombosis are allmatters of surgical judgment. A solemn reminder for all care-givers is that patients undergoing limb amputation areknown to be at high risk for eventual loss of the contralaterallimb dueto thesame factors that causedipsilateraldisease. Of these factors, one is nosocomial, insidious, and completely

preventable: the calcaneal decubitus ulcer. It is thus impera-tive that patients who are at bedrest following amputation,

especially those with diabetic neuropathy, must be provided allavailable measures to protect their heel(s) from pressure ne-crosis. Although a panoply of soft mattresses and foot appli-ances areavailable to padthe heels, theonly fully reliable wayto prevent decubitus ulceration is to avoid all contact andpressure on the area in question. In the case of the heels, this

can be accomplished by placing pillows under the calf andankle such that the heel is not in contact with any surface. Incombination with a well-padded appliance such as theRooke® boot, and with attentive nursing care, this simplemeasure will effectively prevent serious decubitus lesions of the heel.

References1. Esquenazi A: Amputation rehabilitation and prosthetic restoration.

From surgery to community reintegration. Disabil Rehabil 26:831-836,

2004

2. Persson B: Lower limb amputation. Part 1: Amputation methods—a 10

year literature review. Prosthet Orthot Int 25:7-13, 2001

3. Smith DG: Amputation. Preoperative assessment and lower extremity

surgical techniques. Foot and Ankle Clinics 6:271-296, 20014. Sachs M, Bojunga J, Encke A: Historical evolution of limb amputation.

World J Surg 23:1088-1093, 1999

66 R.G. Atnip

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