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Excision of soft tissue Sarcoma ( thigh)

    Overview

    Learn the Excision of soft tissue Sarcoma ( thigh) surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Excision of soft tissue Sarcoma ( thigh) surgical procedure.
    Soft-tissue tumours (STT) are a heterogeneous group of benign and malignant diseases accounting for <4% of all tumours in adults and <8% of all tumours in children. Soft-tissue sarcomas rare malignant tumours derived from mesenchymal cells at all body sites. These rare tumours comprise approximately 1% of all newly diagnosed cancers. The incidence of soft tissue tumours is approximately 2000 cases per annum in the UK.
    Patients may present with a painful or painless swelling that is growing insidiously. Almost 50% arise in the lower limbs (most commonly the adductor compartment of the thigh) and the median age for presentation is 65 years. Concern at to the biological activity of a lesion should arise if the size is >5cm, it is painful, deep to fascia, increasing in size, or recurrence of a previously excised lesion. Each of these five characteristics corresponds to an approximately 20% risk of malignancy. Any lesion presenting with features that are suggestive of STT require referral to specialist centres, where appropriate evaluation and staging will take place.

    Indications

    INDICATIONS:
    Surgical resection of soft tissue sarcomas remains the mainstay of treatment and has been shown to improve overall and disease free survival when compared to oncological management alone. The mode of surgical resection is dependant on the extent of the tumour and the likelihood in achieving clear margins at surgical resection. Broadly speaking, surgery comprises either limb salvage, where the tumour is removed en masse without removal of the affected limb, or limb sacrifice whereby the tumour is removed with the affected limb. The decision on limb salvage versus limb sacrifice is made following careful assessment of the structures involved by the tumour, particularly the involvement of critical nerves and vessels, and the presence of metastatic disease at diagnosis. Also broadly speaking, limb sacrifice would not be offered to a patient with metastatic disease (Grier et al, Sarcoma, 2010).
    The use of adjuvant or neo-adjuvant therapies (predominantly radiotherapy) is assessed on a case by case basis and decisions are made through a disease specific multi-disciplinary team. Certain histological subsets, for example myxoid liposarcomas, are exquisitely sensitive to radiotherapy and this is often given prior to surgical resection. Radiotherapy should be considered for all high grade lesions and whether this is given before surgery or after surgery is at the discretion of the MDT and based on the pre operative extent of the tumour and likelihood of achieving clear surgical margins at surgery.
    SYMPTOMS & ASSESSMENT:
    Patients may present with a painful or painless swelling that is growing insidiously. Almost 50% arise in the lower limbs (most commonly the adductor compartment of the thigh) and the median age for presentation is 65 years. There are, however, age-related variations; embryonal rhabdomyosarcomas occur exclusively in children, synovial sarcomas in young adults and liposarcomas in older people. Concern at to the biological activity of a lesion should arise if the size is >5cm, it is painful, deep to fascia, increasing in size, or recurrence of a previously excised lesion. Each of these five characteristics corresponds to an approximately 20% risk of malignancy. Any lesion presenting with features that are suggestive of STT require referral to specialist centres, where appropriate evaluation and staging will take place. A clinical assessment and examination are mandated, with attention required to regional lymphadenopathy, distal neurovascular deficit and localised skin changes at the tumour site.
    INVESTIGATION:
    Plain radiographs of soft-tissue lesions are helpful to exclude bone lesions with soft-tissue extension and to assess bone invasion from extra-osseous tumours with a risk of fracture. Radiographs should be obtained as the location, presence of any periosteal reaction, erosion (e.g. glomus tumour, PVNS) soft-tissue mineralisation (e.g. synovial sarcoma) is useful for characterisation.[46] Soft-tissue tumours are more difficult to diagnose specifically from imaging, however there may be characteristics which can help to determine aggressiveness or identifiable tissues such as fat, calcification or haemorrhage. Matrix calcification or ossification may be found in synovial sarcomas and in the rarer mesenchymal chondrosarcomas or soft-tissue osteosarcomas.
    MRI sequencing of the affected limb is valuable to define extent of the lesion and local invasion of critical structures and to characterise the lesion prior to biopsy. If surgery is planned this will define the margins to neurovascular structures and the involved musculature, joints or tendons. There is extensive overlap of the soft-tissue sarcoma appearances with MRI; the majority have a low signal T1 and heterogeneous high signal T2 appearances. Exceptions to this may include high T1 signals in some liposarcomas and low T2 signal in desmoid fibromatosis and PVNS. The characteristics of particular tumours may be emphasised, such as a serpiginous pattern in vascular tumours, dystrophic calcification in synovial sarcomas or blooming artefact caused by the haemosiderin content of diffuse-type PVNS. MRI should be performed before biopsy as the tissue characteristics may alter. Contrast is reserved for targeting the biologically active areas of tumours for biopsy, although it risks nephrogenic systemic fibrosis in patients with chronic renal impairment.
    Systemic staging will requires chest CT or PET CT to identify other biologically active lesions. Bone scintigraphy is not normally required. Systemic staging for soft-tissue sarcomas principally involves chest radiographs and chest CT for pulmonary metastases. In pelvic or retroperitoneal primaries, CT of the abdomen and pelvis would be included; PET CT is useful to identify other biologically active lesions in neurofibromatosis type 1. WBMRI is reliable to detect extra-pulmonary metastases in myxoid liposarcomas which rarely metastasise to the chest.
    OPERATIVE ALTERNATIVES:
    The options of planned marginal resection following radiotherapy versus en bloc resection with excision of the distal femur and reconstruction with a distal femoral endoprosthetic replacement were discussed. The latter option is felt not to confer a survival advantage in terms of local recurrence or the development of metastatic disease and carries a high risk of periprothetic infection in the presence of radiotherapy.
    NON-OPERATIVE ALTERNATIVES:
    In the presence of significant comorbidities, the patient may be offered radiotherapy alone as local control of the tumour. There is a disease free survival advantage conferred by surgical resection in combination with radiotherapy.
    CONTRAINDICATIONS: Sufficient comorbidities to preclude surgical intervention.

    Setup


    The procedure should be performed by a surgeon designated by the local sarcoma multidisciplinary team (MDT). All cases are discussed in a disease specific MDT with careful scrutiny of the radiology, histology and discussion of the appropriate surgical and oncological management.
    This patient had received neo-adjuvant radiotherapy
    At the time of surgery, the procedure is performed in a laminar flow theatre.
    Pre operative antibiotics, as designated by the local hospital protocol, are given at induction of anaesthesia.
    The use of a tourniquet is at the discretion of the surgeon but is often not used as this allows visualisation of the vessels which often require dissection free from the tumour.
    The patient is positioned supine with a sandbag behind the buttock to maintain the limb in a neutral position with the patella pointing directly upwards. The limb can therefore be manipulated during surgery to allow access to the entire quadriceps compartment.
    The anaesthetic technique is at the discretion of the anaesthetist but should include regional or spinal anaesthesia, often with a combined epidural, for post operative analgesia.
    The instrument sets should include an orthopaedic oncology set, including vascular instruments, and a vascular set, including non crushing clamps. Appropriate sized suture material should be available before commencing the case in the event of vascular injury requiring repair.

    Operation – 1

    The coronal MRI post radiotherapy demonstrating the lateral extent of the tumour extending into vastus lateralis.

    The axial MRI of the lower left thigh demonstrates the tumour wrapping around the femur but sparing the vessels. There has been a change in the internal appearances of the tumour after radiotherapy representative of the likely necrosis and liquefaction of the tumour.

    The leg is prepared and draped. The approach to the distal thigh is through a direct anterior approach to allow access to the quadriceps compartment. This can be extended proximally to expose the whole quadriceps compartment if needed. It allows allows easy access to the femoral vessels if required. The marks demonstrate the position of the patella (1) so the incision can be extended across the knee if required.

    The skin incision extends from proximal to distal overlying the patella in the midline.

    Following the skin incision and dissection through the subcutaneous fat, the fascia is divided in line with the incision.

    The procedure begins with the approach to the quadriceps comaprtment. The biopsy tract is included in the incision so this can be removed along with the tumour. Often, the tract cannot be removed en masse with the tumour but so long as all potentially contaminated material is excised at the time of tumour removal, the risk of recurrence at the biopsy tract will be reduced. The rectus femoris tendon (1) is divided longitudinally to expose the vasti beneath.

    Following skin incision and mobilisation of the biopsy tract, the fascia is incised to expose the common tendon. This is then divided longitudinally to expose the intermuscular plane between rectus femoris and vastus medilais beneath (1). This plane can be developed down to the suprapatellar pouch and proximally to the origin of the vasti from the proximal femur.
    As the tumour was completely within vastus medialis, the overlying rectus femoris could be preserved.

    Having mobilised rectus from the deeper vasti, the dissection begins medially. Sartorius is mobilised anteriorly to expose the intermuscular septum (1).

    The tumour can now palpated on either side and is felt fully contained with the distal quadriceps

    The vessels are exposed proximally by dividing the roof of Hunter’s canal. The boundaries of Hunters canal are formed by sartorius, adductor longus and vastus medialis The vessels are then traced distally dividing the perforating branches supplying the tumour. The extent of the distal dissection is governed by the position of the tumour but as the vessel dives into the popliteal fossa, exposure can become difficult.

    During anterior distal dissection elevation of the lateral insertion of rectus (1) is required.

    As the tumour extends very close to the suprapatellar pouch and laterally around the femur, the lateral insertion of rectus femoris (1) is mobilised from the patella insertion. The muscle is divided at its musculotendinous junction leaving a cuff of tendon to repair following removal of the tumour.

    The antero-lateral extent of the dissection involves mobilising the vastus lateralis from the lateral intermuscular septum, tying off the perforating branches coming through the septum.

    Again, this step is during the antero-lateral dissection during which elevation of the overlying quadriceps from the lateral intermuscular septum is undertaken. (1) Patella (2) Lateral femoral condyle.

    At this stage, the lateral insertion of rectus femoris (1) can be reflected to expose the entirety of the tumour, with the medial insertion of rectus femoris and sartorius elevated medially. The tumour is now almost completely exposed and mobilised apart from the deep margin abutting the femur, and its distal insertion to the quadriceps tendon.

    The proximal dissection of the tumour begins by dividing vastus above the palpable level of the tumour.

    The level at which the muscle is divided is dictated by careful assessment of the pre operative imaging as well as manual feedback at the time of surgery. As can be seen, the muscle is divided down to and including the deep layer of periosteum overlying the femur (1).

    As can be seen, the tumour within the surrounding muscle has been exposed medially and laterally and the proximal muscle has been divided. (1) Proximal pole of patella. (2) Tumour encased within muscle. (3) Reflected lateral insertion of rectus.

    The distal margin of the tumour can now be defined by dividing through the quadriceps tendon at a safe distance from the lower extent of the tumour.

    At this stage, the careful process of mobilising the tumour from the femur can begin. Using a Cobb (1), the periosteum is elevated from the femur (2) with the overlying tumour. This is the point at which the tumour is most at risk of spillage and contamination and great care must be taken to not stray from the bone margin into the overlying tumour.

    The periosteal margin can also be approached from distal to allow the tumour to be very carefully elevated from the femur. (1) Anterior cortex of femur. (2) Tumour. (3) Proximal pole of patella.

    Further deep elevation is completed until the entire deep extent of the tumour has been elevated from the underlying femur.

    The tumour is finally delivered from the femur leaving exposed bone at the base of the dissection without overlying periosteum. (1) Divided quadriceps insertion. (2) Anterior femur. (3) Medial belly of rectus and sartorius reflected medially. (4) Reflected lateral insertion of rectus femoris.

    Once delivered from the patient, the tumour can be inspected and marked with sutures to allow orientation by the examining pathologist. As can be seen from the superficial surface, no macroscopic evidence of tumour can be seen but rather the tumour is fully contained within a cuff (or margin) of normal overlying muscle.

    On the deep surface of the tumour, again no macroscopic evidence of tumour is seen. The deep margin in this case comprises the periosteum which has been elevated from the underlying femur.
    The histology revealed this to be a high grade undifferentiated and pleomorphic soft tissue sarcoma arising from the distal quadriceps compartment.

    Operation – 2

    Following removal of the tumour, haemostasis is achieved and the cavity irrigated thoroughly with normal saline via pulsed lavage. All gloves and instruments that have been used for the excision are changed. The reconstruction can now begin.

    Having washed the cavity left by the tumour, 2 deep suction drains are inserted. (1) Quadriceps insertion on proximal pole of patella. (2) Anterior cortex of distal femur. (3) Reflected medial insertion of rectus and underlying sartorius. (4) Reflected lateral insertion of rectus femoris.

    The previously elevated vastus lateralis is re-attached to the quadriceps tendon using heavy, non absorbable sutures.

    Further closure in layers is performed apposing the remaining quadriceps using monofilamentous sutures. The subcutaneous layers are closed with absorbable sutures and the skin closed with clips.
    Due to the high incidence of wound complications following radiotherapy for soft tissue sarcoma, a vacuum assisted dressing is often applied at low pressure to prevent wound dehiscence. An overlying bandage is applied and the knee immobilised in a ‘cricket pad’ splint.

    Post Operative

    Antibiotics are given in line with the local hospital protocol. In this case, a further 24 hours of intravenous antibiotics wee given.
    The drains are removed when less than 100ml total drainage in a 24 hour period.
    The knee is immobilised in a straight position until the wound has healed at which point gentle knee flexion can commence, usually after a period of 2 weeks.
    Physiotherapy is imperative given the extent of the quadriceps dissection.
    The wound is reviewed at 5 days post operation and if no concerns, the vacuum dressing is removed and a barrier dressing applied.
    The skin clips are removed no sooner than 2 weeks after operation. In light of the pre operative radiotherapy, the clips are often left in situ for longer than would normally be advised due to the risk of wound dehiscence.
    The patient is discharged home when there are no longer concerns about the wound but is reviewed regularly due to the high incidence of late wound complications on the background of neo-adjuvant radiotherapy.
    The tumour os processed by a specialist musculoskeletal pathologist. The response to neo-adjuvant radiotherapy is quantified as the percentage of viable cells seen in the resection specimen. The margins achieved at resection are carefully assessed and quantified in millimetres from viable tumour.
    Following successful removal of the tumour, the patient embarks on standard sarcoma surveillance which in the UK comprises clinical assessment and chest radiography every 3 months for the first 2 years, every 6 months until 5 years post operation, and annually thereafter until 10 years.

    Recommended Reading

    Success following treatment for extremity soft tissue sarcoma is defined in terms of overall and disease free survival. This is quantified by the risk of local recurrence of the tumour or the development of metastases. The risk of disease recurrence is affected by the pathological grade of the tumour, the size of the tumour, the depth, location, histologcal subtype and the margin acheived at surgical resection (Collin et al, J Clin Oncol, 1987; Eiber et al., Ann Surg, 2003). Wide excision with the addition of neo-adjuvant or adjuvant radiotherapy form the mainstay of treatment. Radiotherapy, either given prior to resection or after resection, has been shown to reduce the development of local recurrence but does not improve overall survival (Zagars et al., Cancer, 2003). Pre operative radiotherapy is associated with a slight improvement in overall survival but an increased incidence of wound complications (O’Sullivan et al, Lancet, 2003). The addition of neo adjuvant radiotherapy can allow a closer margin of resection without a detrimental effect on the risk of local recurrence or overall survival when compared to such a margin in the non radiotherapy setting. This planned positive margin allows resection of large tumours in close association to vital structures without detriment to function through sacrifice of these structures, or increase in the risk of local recurrence (Gerrand et al, JBJS-B, 2001).
    Overall survival for extremity sarcomas varies widely but averages between 60 and 75%. This is dependant on a number of variables. The risk of local recurrence is dependant on the margin achieved at surgical resection, the grade of the tumour and the histological variant of the tumour (eg soft tissue Ewings sarcoma, synovial sarcoma, angiosarcoma).

    Reference

    • orthoracle.com

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