Amputation

Intro
Most are probably preventable with early vascular surgeon involvement and patient compliance.
- education needs improvement: eg many diabetics believe early vascular consult will lead to early amputation whereas the opposite is true.
- in any case, amputation is often necessary, and should be embraced as a definitive treatment solution.
The population is ageing and the need is growing.
- DM epidemic contributes: up to 90% of amputations in some communities are in diabetics.
There is no agreed-on definition of an unsalvagable limb.
- most surgeons would agree extensive forefoot and / or heel necrosis is a bad sign.

Level
The more kept obviously the better.
However in any pt with critical limb ischaemia, below knee wounds are going to heal poorly.
- remember these pts have low life expectancy, and time getting over complications is bad time.
- each failed BKA adds up in morbidity, cost, and ultimate functional outcome.
The relative weights of all factors will change pt by pt.
Usual principles stand:
- as much as necessary, as little as possible.
- remove all non-viable tissue.
- preserve optimal residual function.
- minimise surgical morbidity.
Most surgeons agree a BKA without a femoral pulse is destined to do badly.
- a femoral pulse by no-means guarantees success however.
Experienced surgeons are good judges of survival likelihood intra-operatively, based on for example:
- tissue bleeding
- viable muscle
- wounds without tension.
The honest truth is that most vascular patients would not ever use their knee joint much again whether it is left or not: think about the patient in front of you.

Perioperative Issues
Perioperative mortality for lower limb surgery is typically in the 7-15% range.
- most have many co-morbidities and are undernourished and deconditioned by their immobility.
Healing rates of BKAs vary, but 10-20% failure-rate is typical.
- these patients often undergo 1-2 more procedures before AKA revision in 50%.
Post-operative trauma (falls) is one important factor that can be limited.
- no benefit for casting to prevent trauma from one small study (cf bandaging).

Post-operative Complications
These are amongst the worst patient groups in the world.
- most are in the last months of their lives, and any little problem can prove fatal.
- they are rarely given the respect they deserve by the operating team.
DVT is common due to immobility and these pts should be given prophylaxis.
Septic complications from delay in definitive removal of the septic focus are problematic.
There are two types of postoperative pain:
- stump pain and phantom pain.
- together affect 50-80% of patients, usually episodic and not a major problem.
- prolonged pre-amputation pain is a predictor of postop pain.

Outcomes
Most of these operations are palliative.
- survival was 57% for BKAs and 39% for AKAs at 3yrs in one major study.
- at 2 yrs, 15% of successful BKAs will need an AKA, and 15% will have lost their other leg.
Most elderly pts will not cope with the arduous rehab needed to walk again.
- but most can go home with a wheelchair.
Many AKAs are chosen based on lack of rehab potential, and the ratio of BKAs to AKAs conducted is ~1:1.

Amputation vs Revascularisation
Although some amputations are preventable, some revascularisations are conducted with futility and morbidity and cost.
- prior bypass failure prolongs BKA incisional healing.
A lot of research has gone into defining how much foot blood flow can support wound healing of ulcers.
- but not much consideration has been given to the type of wounds in these patients: degrees of sepsis and so-forth.
Look at the problem from three sides:
i) the technical issue of the revascularisation
ii) the foot wound healing issues
iii) the co-morbidities of the patient.
Patients with marginal prospects in >1 categories are generally considered fairly poor candidates.
Pre-op CRP correlates with poorer patient survival, foot healing and limb salvage.
- low serum-albumin also correlates with mortality & length of stay.

Indications

Traditionally divided into:
i) acute ischaemia
ii) chronic ischaemia
iii) foot infections.

BKA

In an appropriately consented, investigated and prepared patient.

Mark the limb to be amputated. Check this with the patient, all available radiology, nursing staff and relatives.

GA / spinal anaesthesia. IV abx including penicillin if gangrene is present.

Prep & drape

Leg free draped and supported un upturned bowl.

Foot wrapped with a sterile stockingette to exclude any gangraneous tissue.

I use Burgess long posterior flap. I mark incisions:

   Level of bone division is 8cm per meter of height (12cm for average adult) below tibial tuberosity (TT). The absolute minimum is 6cm.

   The anterior skin incision is 2cm distal to the tibial transection level and encompasses 2/3 of the circumference of the limb.

   The posterior flap is marked to be made at a distance distal to the anterior incision which is equal to the transverse diameter of the leg. The two levels are joined with a vertical line.

image

I incise the anterior skin flap only with 15 blade

I ligate  the great saphenous vein with 2/0 Vicryl ties in the superficial fat

I incise the deep fascia of the anterior compartment and divide the muscles with diathermy.

Lateral to tibia I divide the tibialis anterior, extensor digitorum longus and extensor hallucis longus.

I divide the anterior intermuscular septum to expose the lateral compartment and the peroneus longus muscle.

This exposes the interosseous membrane where the anterior tibial artery, which is ligated with 0 Vicryl ties.

I follow the deep peroneal nerve to its birfurcation by dividing peroneus longus and finding the common peroneal nerve, which I retract with an artery and divide short with scissors

I then raise the periosteum of the tibia circumferentially with an elevator about 1cm proximal to the level of tibial transection.

I pass a Gigli saw behind the tibia and cut the posterior half of the bone and then bevel the anterior half at a 45 degree angle.

I free the remaining soft tissues from the fibula, taking care to protect the peroneal artery and I cut the fibula 2cm shorter than the tibia with bone cutters.

I then use a rasp to round off the edges of the tibia and fibula.

I divide the muscles of the deep posterior compartment of the calf and divide at the same level as the tibia

I identify the posterior tibial vessels and posterior tibial nerve. I suture ligate with 0 Vicryl the vessels and retract the nerve with forceps and cut it short with scissors.

I then ligate the peroneal vessels as they emerge from behind the fibula

Fashion the posterior flap by transecting the soleus muscle and other soft tissue remaining at the level of the distal skin incision, ligating the short sapenous vein to complete the amputation.

I hand off the leg

I open the avascular plane between gastronemius and soleus and remove soleus up to the level of the tibia as it contributes no blood supply to the flap.

Secure haemostasis. I irrigate the stump with water and use bone wax if there is any bleeding from tibial marrow cavity.

Trim flap as necessary to avoid dog ear formation

I place a subfascial 10F redivac drain which is not sutured so that it can be removed without removing the dressing

Suture gastrocnemius fascia to fascia overlying tibialis anterior, pretibial fascia and extensor muscles using 1 vicryl matress suture.

3/0 interrupted nylon to skin

Opsite dressing

Softban & bandage

Infuse 0.5% marcain 5ml/4hrs, leave drain off suction 15minutes

Leave dressings 72hrs

I request early mobilization with hip and knee physiotherapy.

Sutures are removed no earlier than 14 days

As soon as the wound has healed a temporary pylon is fitted.

What are the contraindications to BKA

Severe OA of knee

Contractures and ankylosis of hip and knee

Hemiparesis of limb

Flaps infected or non-viable

Sensory neuropathy of flaps

What do you do if the tissues do not bleed when cut

Move to a higher level. If there is no bleeding at the highest level compatible with BKA (about 6cm from tibial tuberosity) do not revise to AKA unless discussed with patient beforehand. They are likely to need revision to AKA.

 


AKA

In an appropriately consented, investigated and prepared patient.

Mark the limb to be amputated. Check this with the patient, all available radiology, nursing staff and relatives.

GA. Supine sandbag beneath buttock. IV abx including penicillin if gangrene is present.

Prep & drape

Leg free draped and supported un upturned bowl.

Foot wrapped with a sterile stockingette to exclude any gangraneous tissue.

The optimal length of tibial transection is 25cm from the greater trochanter; minimum is 15cm from greater trochanter; minimum is 15 cm from medial line of knee joint.

I then fashion skin flaps about 10cm distal to level of bone transection.

My posterior flap is slightly longer than my anterior flap by about 2cm to bring the suture line off the bed.

I use knife dissection with a 15 blade avoiding diathermy.

I incise the skin and superficial fascia. I ligate the LSV with 2/0 Vicryl ties. I continue the incision down to deep fasisa.

I divide the quadriceps muscles anteriorly (rectus femoris, vastus lateralis, vastus intermedius and as I approach vastus medialis I remain superficial to identify the sartorius muscle.

I identify femoral vessels  and the saphenous nerve beneath sartorious and suture ligate them with 0 vicryl siture tie individually.

I continue dividing the muscles laterally and medially until the periosteum is reached.

The termination of profunda femoris vessels may be encountered on the femeur between adductor magnus and vastus medialis.

I ligate if necessary & divide profunda vessels

When sufficient muscle has been divided I strip the periosteum circumferentially from the femeur with a periosteal elevator.

I divide the femeur with a Gigli saw

I then use a rasp to smooth the cut area of the bone and apply bone wax if there is any bleeding from the marrow cavity

I then continue to divide the muscles medially and posteriorly looking for the sciatic nerve between biceps femoris and semitendinosus. This nerve has a large vasonervorum which is stripped from the vessel and ligated with 2/0 Vicryl ties and divided.

I pull the sciatic nerve down, ligate & let retract

I then complete  division of the posterior muscles

I hand off the limb

I irrigate the wound with warm saline and secure haemostais with careful diathermy of bleeding points and pressure.

I place a 10F redivac drain below the fascia and I suture the deep fascia of the anterior and posterior compartments in multiple layers with 0 vicryl to reduce dead space and prevent bone herniation.

The drain is not sutured

I trim the flaps to ensure that there is no necrotic skin or dog ears

I Suture the skin with interrupted 3/0 Nylon

Opsite dressing

Softban & bandage

Infuse 0.5% marcain 5ml/4hrs, leave drain off suction 15minutes

Alternatively an epidural catheter can be placed inside the epineurium of the sciatic nerve for continious LA infusion.

Leave dressings 72hrs

I request early mobilization with hip physiotherapy.

Sutures are removed no earlier than 14 days

As soon as the wound has healed a temporary pylon is fitted.

 

 


Foot amputations

There are four groups of procedure:

Digit and ray amputation

Transmetatarsal amputation

Midfoot amputation (Lisfranc)

Through ankle amputation (Syme)

In general only successful in diabetic gangrene or the limb has been revascularized in a non-diabetic.

 


Digit amputations

ie toe

In an appropriately consented, investigated and prepared patient.

Mark the toe to be amputated. Check this with the patient, all available radiology, nursing staff and relatives.

GA. IV abx including penicillin if gangrene is present.

Prep & drape leaving the foot free.

I separate the toes using ribbon gauze and asking my assistant to pull the toes to be preserved away from that which is to be amputated.

I mark a racket incision (inset one below) at the level of the level of the proximal phalanx.

image

I use a 15 blade and incise down to the bone of the proximal phalanx

I divide the bone just distal to the capsule of the MTP joint so as to avoid damaging the transverse metatarsal ligament.

I divide the proximal phalanx with bone cutters and round the edges with a rasp

I obtain haemostasis, wash out the wound and close the skin with interrupted 3/0 Nylon.

Softban & bandage

Leave dressings 72hrs

I request early mobilization with hip, knee and ankle physiotherapy to prevent contractures.

Sutures are removed no earlier than 14 days

 


Ray amputation

ie complete resection of phalanx and partial resection of corresponding metatarsal
-indicated when there isn't enough viable tissue to cover for disarticulation of the simple digit amputation
- racquiet like incision extended  to dorsal foot, resection under tension then closure

In an appropriately consented, investigated and prepared patient.

Mark the toe to be amputated. Check this with the patient, all available radiology, nursing staff and relatives.

GA. IV abx including penicillin if gangrene is present.

Prep & drape leaving the foot free.

I separate the toes using ribbon gauze and asking my assistant to pull the toes to be preserved away from that which is to be amputated.

I mark the skin incision on the plantar surface at the metatarso-phalyngeal skin crease and on dorsum of foot I mark a racket-shaped incision coverging at the level of the metatarsal heads. The plantar and dorsal incisions are joined by a parabolic line

I make the incision with a 15 blade down to the level of bone beginning on the dorsum.

I spare the digital arteries on both sides of the amputated digit

I use a periosteal elevator to elevate the periosteum and soft tissues from the metatarsal head.

I divide the metatarsal in the mid-shaft with bone cutters and smooth it with a rasp

I then extend the toe and transect the plantar tendons so that they retract and divide the remaining soft tissue posteriorly flush with the bone

I wash out the wound with saline and trim the flaps to avoid dog ears and suture the skin flaps only with interrupted 3/0 Nylon over a penrose drain.

Softban & bandage

Leave dressings 72hrs

I request early mobilization with hip, knee and ankle physiotherapy to prevent contractures.

Sutures are removed no earlier than 14 days

If the open technique is chosen, I divide the skin at the same level and leave the tissue to granulate, cutting the metatarsal shaft shorter so that it is covered by viable muscle.

A split skin graft can be placed later to aid healing once sepsis has subsided.


Transmetatarsal amputation

In an appropriately consented, investigated and prepared patient.

Mark the fot to be amputated. Check this with the patient, all available radiology, nursing staff and relatives.

GA. IV abx including penicillin if gangrene is present.

Prep & drape leaving the foot free.

I mark the skin incision on the plantar surface at the metatarso-phalyngeal skin crease and on dorsum of foot an incision at the level of the metatarsal heads. The plantar and dorsal incisions are joined by a parabolic line

image

- ie plantar flap slightly longer, tendons resected under tension to proximal edge of wound

I make the incision with a 15 blade down to the level of bone beginning on the dorsum.

I ligate with 2/0 Vicryl ties the digital arteries

I use a periosteal elevator to elevate the periosteum and soft tissues from the metatarsal heads.

I divide the metatarsals with a bone cutter or saw and round the edges with a rasp.

I then extend the toes and transect the plantar tendons so that they retract and remaining soft tissue posteriorly flush with the bone

I wash out the wound with saline and trim the flaps to avoid dog ears and suture the skin flaps only with interrupted 3/0 Nylon over a penrose drain.

Opsite dressing

Softban & bandage

Leave dressings 72hrs

I request early mobilization with hip, knee and ankle physiotherapy to prevent contractures.

Sutures are removed no earlier than 14 days



Partial transmetatarsal amputation

In an appropriately consented, investigated and prepared patient.

Mark the fot to be amputated. Check this with the patient, all available radiology, nursing staff and relatives.

GA. IV abx including penicillin if gangrene is present.

Prep & drape leaving the foot free.

Can be performed as a closed or open procedure open is chosen if there is any question as to viability of skin or residual sepsis

With the closed technique, I mark the skin incision on the plantar surface at the metatarso-phalyngeal skin crease to remove the lateral 2-3 digits and on dorsum of foot an incision at the level of the metatarsal heads. The plantar and dorsal incisions are joined laterally by a parabolic line and longitudinal line between the toes to be removed and those that will be preserved.

I incise the skin and soft tissue down to bone preserving the digital artery on the toe which will not be amputated.

I tie the other digital arteries with 2/0 Vicryl ties

I use a periosteal elevator to elevate the periosteum and soft tissues from the metatarsal heads.

I divide the metatarsals with a bone cutter and round the edges with a rasp.

I then extend the toes and transect the plantar tendons so that they retract and remaining soft tissue posteriorly flush with the bone

I wash out the wound with saline and trim the flaps to avoid dog ears and suture the skin flaps only with interrupted 3/0 Nylon over a penrose drain.

If the open technique is chosen, I divide the skin at the same level and leave the tissue to granulate, cutting the metatarsal shafts shorter so that they are covered by viable muscle.