Limb Salvage Surgery

Limb Salvage Surgery

By Dr. KM Liau

Limb salvage surgery is made possible due to advances in:

1. Neoadjuvant and adjuvant chemotherapy

2. Good diagnostic imaging (CT Scan, MRI)

3. Advanced surgical techniques

Indications

1. Optimum oncological margins achievable

2. Moderate soft tissue extension

3. Neuro-vascular bundles not compromised

4. Metastasis absent or responsive to curative treatment

5. Patient in good general condition

6. Free of systemic and local infection

Contraindication

1. Major neurovascular involvement.

2. Pathologic fracture - spread via haematoma to adjacent compartment.

3. Inappropriate biopsy site - contamination of vital compartments.

4. Infection at the site of surgery.

5. Extensive soft tissue and muscle involvement - unable to reconstruct

a functional extremity.

6. Tumour recurrence.

Does it affect survival?

Studies have found no effect on long term survival

However this is true only if:

1. Patient received neoadjuvant and adjuvant chemo.

2. Wide surgical margins achieved.

Rate of local recurrence

5-10% - same as amputation (but not disarticulation)

Immediate morbidity

Skin necrosis / infection - due to:

- Large cutaneous flaps are raised

- The skin had already been stretched and thinned out by the tumour.

Long term morbidity

1. Infection

2. Nonunion of bone/implant interface

3. Fractures of allograft.

4. Loosening - For prosthesis with mobile joints.

Principles for upper limb amputation

1. Resection at the level of proximal humerus is better than a forequarter amputation.

2. Preservation of hand function as much as possible.

Principle for lower limb amputation

1. Below knee amputation better than foot / distal tibial resection

2. Hierachy of oxygen consumption:

a) Below knee amputation (least O2 consumption)

b) Prosthesis with mobile knee joint

c) Arthrodesis of knee joint

d) Above knee amputation

e) Hip disarticulation (most O2 consumption)

(the more the oxygen consumption, the least the functional outcome to patient)

Misconception

Young adults usually think that limb salvage, esp. with mobile knees will enable them to continue normal activities with no change in performance.

They and their families must realise that NONE of the reconstructions will enable them to have a functionally normal limb, and that they will always be partially disabled.

Guidelines:

1. Identification and preservation of key neurologic and vascular structures.

2. Resection of affected tissue should have a wide margin with normal tissue cuff in all directions

3. All previous biopsy site and all potentially contaminated tissue are removed enbloc.

4. Reconstruction of axial skeleton.

5. Adequate motor reconstruction by regional muscle transfers.

6. Adequate soft tissue coverage to reduce skin flap necrosis and secondary infection

Reconstruction option

4 major methods:

1. Resection arthrodesis

2. Allografts: osteoarticular, intercalary

3. Allograft prosthetic composite

4. Endoprosthesis

Growing Child

If the patient is young (<12 years old) and had not finished growing when they had their prosthesis/allograft put in, it may need to be replaced as they grow taller.

This problem can be overcome by preserving the growth plate.

Currently expandable endoprosthesis are also available in the market. However the cost of it made it almost unaffordable to most of our patients.

Issues to be discussed with patient and family:

1. Small increase in local recurrence 5-10% but no difference in long term survival.

2. Morbidity increased - increased hospital stay, increased number operations.

2. Durability of endoprostheses are variable especially those with mobile joint.

3. Function better especially for the upper limb but none will function as "normal" limb.

4. No matter what type of surgery is done (limb salvage or amputation), if the premorbid personality is normal with good psychosocial adjustment, then the outcome will be good.

Case Study

12 year old boy presented with pain and swelling of left knee for past 3 months.

Lateral view

Note the swelling over distal third of his left thigh

Plain X-ray

Note the pathological fracture over lower third of left femur.

Preliminary diagnosis of Osteosarcoma was made.

Immobilization with Thomas Splint

The left lower was immobilized with Thomas splint while awaiting for further staging and investigation

Local Staging

MRI - T1 Weighted Image

There is presence of an intramedullary as well as an extramedullary mass lesion in the distal end of right femur with cortical destruction.

The mass is heterogenously isointense to muscle on T1

MRI-T2 Weighted Image

The mass shows heterogenous enhancement post intravenous gadolinium.

Systemic Staging

CT Lung

No lung metastasis noted

Whole Body Bone Scan

IV 99m Tc-MDP 25.6mCi given and scan performed 3 hours post injection.

Presence of increased tracer uptake in the left distal femur (at the metadiaphysis).

The increase tracer accumulation in the right thigh is due to the urinary catheter and the urine bag.

No other abnormal tracer uptake seen.

Physiological tracer uptake in kidneys and urinary bladder.

Biopsy

Biopsy done over the medial aspect of left thigh, 2cm above patella.

2cm incision made and the soft tissue was opened layer by layer through vastus medialis muscle up to the bone.

Cone biopsy done.

Haemostasis secured with bone wax.

Histology report:

The section of bone shows a malignant tumour within the marrow spaces and destroying the bone in a few areas.

The tumour cells are pleomorphic, hyperchromatic with scattered tumour osteoids noted.

Consistent with diagnosis of Osteosarcoma.

Neo-adjuvant Chemotherapy

He was started on 3 cycles of pre-op chemotherapy consisting of:

Cisplatin D1-D3

Adriamycin D1-D3

Limb Salvage Surgery

Incision made extending from mid thigh till upper 1/3 of left leg.

Soft tissue and muscle opened layer by layer.

Wide resection of tumour done with 3 cm of normal tissue cuff.

The femoral neurovascular bundle was carefully preserved.

The arrows point to the femoral artery.

Wide Resection of Tumour

The widely resected tumour includes 5 cm of proximal and distal margin.

The femoral condyle together with the articular surface are resected as well.

The total length of resected femur measures 26 cm.

Preparation of Allograft

The allograft is first immersed in povidone soak for 30 minutes.

The muscular attachments and periosteum were then stripped clean from the femur.

Preparation of Allograft

The allograft is then immersed in a solution containing 2 G of Rocephin and 3 G of Vancomycin.

It is wrapped with a thin layer of gauze for more even distribution of antibiotics.

It is left in the immersion for 20 minutes.

Preparation of Allograft

The condyle of the femoral allograft is then cut for total knee replacement prosthesis fitting.

Preparation of Bone Cement

Polymethylmethacrylate bone cement is being prepared into a 25 cc syringe.

Injection of Bone Cement

Bone cement was injected into the medullary canal of the reamed allograft under high pressure.

Pressurization of Bone Cement

The highly pressurized bone cement within the femoral allograft is evidenced by the intramedullary fat being squeezed out from the cortical surface.

Insertion of Femoral Component

The femoral component of total knee replacement being inserted into the allograft.

Insertion of Tibial Component

Bone cement was injected into the proximal tibia as a preparation for insertion of tibial component.

Plating of Allograft

Dynamic Compression Plate used to fix the allograft to proximal femur.

Final Fixation

The final fixation is shown here.

The femoral-allograft interface is reinforced with extracortical bone bridge using autogenous bone graft harvested from Iliac crest.

Wear and tear

Prosthesis very rarely break. But after several years, there may be signs of wear and tear.

It isn't possible to generalise about this, as there are so many different types and makes of prostheses.

But after some time, the plastic polyethelene surfaces of the joint can become worn and need replacing.

The metal rod inserted into the remains of patyient's own bone can sometimes become loose and also need replacing or strengthening.

Knee prosthes nearly always need replacing after 10 - 15 years at most.

This time period is getting longer though, as better joints are being designed and made.

Conclusion

The success of limb salvage depends on prompt detection and early referral by the primary care doctor, and on a coordinated and carefully thought out sequence of staging, preoperative treatment, limb salvage surgery, and post-salvage support and follow-up by a dedicated team of care givers.

The goals of limb salvage are the complete eradication of the tumor with minimal complications while maintaining acceptable function, durability, and cosmesis of the limb.

The limb salvage surgeon must also consider the barriers to limb salvage that may exist in each particular case.

Achieving a surgical margin that will ensure a low rate of local recurrence is paramount.

The selection of the surgical technique for reconstruction depends on the wishes of the patient, the location of the tumor, and the extent of the surgical defect created by the resection.

In certain cases and especially in tumors in the distal lower extremity, treatment by amputation may be preferable to limb salvage.

Both limb salvage and amputation result in mild physical and psychological disabilities.

Patients adapt and adjust best if they are fully informed and able to participate in the decision making process.