Principles of Biopsy

Aims

 

1.  Provide representative sample

2.  Not compromise definitive treatment

 

Biopsy

 

Options

 

Open

- incisional biopsy

- excisional biopsy

 

Image guided

- fine needle aspirate

- core needle biopsy

 

Open biopsy

- larger sample of tissue

- larger tract to later excise

- higher risk of complication such as infection / hematoma

 

Results

 

Dirks et al World J Surg Oncol 2023

- incisional biopsy of 332 malignant musculoskeletal tumours

- sensitivity 100%, specificity 97.6%

 

Tsukushi et al Arch Orthop Trauma Surg 2010

- CT guided needle biopsy in 207 patients with musculoskeletal lesions

- diagnostic accuracy 90%

 

Birgin et al, Cancer 2020

- meta-analysis of 2680 patients with soft tissue sarcoma

- Incisional: sensitivity 96%, specificity 100%

- Core needle: sensitivity 97%, specificity 99%

- complication RR = 0.14 favoring needle

 

Performed by treating surgeon at treatment centre

 

Results

 

Mankin et al, JBJS 1982 

- 329 sarcoma patients

- complication rate > 5 times higher when performed by other surgeon / other hospital

- 60% major error in diagnosis

- 20% treatment compromised by biopsy

- 4.5% had unnecessary amputation due to poor biopsy

 

Mankin et al, JBJS 1996

- musculoskeletal tumour society

- follow-up study from 1982 (n=597)

- rate of diagnostic error 17.8%

- problems with biopsy causing change in treatment to more difficult or complex procedure 19.3%

- change in outcome attributed to biopsy 10.1%

- 18 patients had unnecessary amputation

 

Open Biopsy Technique

 

Pre-operative

 

Tumour staging first / all imaging obtained / images reviewed with experienced MSK radiologist

 

Treating surgeon does biopsy at treating hospital

- discussed with tumour centre if not possible

 

Ensure expert pathological facilities

- experienced MSK pathologist

- frozen section available

 

No pre-op antibiotics / infection always in differential diagnosis

 

Tourniquet

- no exsanguination

- release before closure and obtain hemostasis

 

Intra-operative

 

1.  Approach

- plan with future OT in mind

- all aspects of biopsy tract must be excised later

- incision must be incorporated in definitive surgery

- violate one compartment only / trans-muscular

- incision is longitudinal, no undermining skin edges

- don't expose NV structures

- meticulous hemostasis

 

2.  Biopsy

- round cortical windows / decreased stress-risers

- swab taken / tissue for M/C/S

- tissue for FFS / histology

- no closure until discussion with pathologist on phone

- ensure they have enough to make a definitive diagnosis / cell line / grade 

 

3.  Closure

- plug bone windows with PMMA / minimises tumour spread 

- achieve hemostasis

- closure in layers

- drain exit site in line with and through wound

- subcuticular suture to skin

- firm dressing

- immobilise 

 

Post operative

 

Very careful post op

- pathological fracture can change outcome

 

Team approach

- pathologist / radiologist / oncologists / radiation oncologist

- all results are reviewed to ensure correct diagnosis and management