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Computer navigated P1 hemipelvectomy for chondrosarcoma and GRAFTJACKET (Wright Medical) reconstruction

    Overview

    Professional Guidelines Included
    Learn the Computer navigated P1 hemipelvectomy for chondrosarcoma and GRAFTJACKET (Wright Medical) reconstruction surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Computer navigated P1 hemipelvectomy for chondrosarcoma and GRAFTJACKET (Wright Medical) reconstruction surgical procedure.
    Chondrosarcoma (CS) is the second most common primary malignant bone sarcoma, and the most common in adults. These tumours range from low to high-grade malignant cartilage tumours which may metastasise to the lungs. They are relatively insensitive to chemo- or radiotherapy, due to hypovascularity, meaning that surgery is the principal treatment. Five year survival ranges from 99% for low grade to 24% for dedifferentiated chondrosarcomas.
    The pelvis is the fourth most common site of primary malignant bone tumours in all age groups after the distal femur, proximal femur and proximal humerus. Chondrosarcomas can also arise in other pre-existing conditions, particularly multiple osteochondromas and multiple enchondromatosis (e.g. in Ollier disease and Maffucci syndrome).Enneking and Dunham classified pelvic resections into: type I (ilium), type II (periacetabular), and type III resection (obturator). Resections involving the sacrum are referred as type IV. Achieving adequate surgical margins to ensure the tumour is excised-bloc is the guiding oncological principle to avoid local recurrence; local recurrence is often accompanied by metastasis and can only be controlled by en-bloc excision with wide surgical margins. Resection of a tumour from the pelvis often requires reconstruction of the large bone and soft-tissue defect; partial resection of the ileum preserves the pelvic ring which is thought to maximise function but risks inadequate surgical margins and herniation of the peritoneum through the resultant defect. Reconstruction of the pelvic bone and soft-tissue defect using the Graftjacket (Wright Medical), a human dermal allograft matrix commonly used in foot & ankle and shoulder surgery to repair soft-tissue defects, is a novel use for this device (http://www.wright.com/healthcare-professionals/graftjacket).
    Here I describe the use of computer navigation to excise a pelvic chondrosarcoma and reconstruct the defect using a Graftjacket.
    Enneking WF, Dunham WK. Resections and reconstruction for primary neoplasms involving the nominate bone. J Bone J Surg (Am) 1978;60(6):731-746. PMID: 701308

    Indications

    INDICATIONS
    The indications for hemi-pelvic excision are primary and secondary malignant tumours, but in rare cases of infection or trauma pelvic resections may be required. Type I resections (ileum) are the least challenging resections and reconstructions. If the ilio-ischial bar can be retained, as in this particular case using navigated assisted surgery, then the pelvic ring can be preserved and limited if any reconstruction is required. At most, to prevent visceral herniation a Graftjacket (Wright Medical) collagen matric scaffold can be used to replace the resected ileum for reattachment of the abdominal and gluteal muscles.
    If the ilio-ischial bar is resected, then the pelvic ring has been disrupted and load through the acetabulum cannot be transmitted to the sacrum. Options include avoiding reconstruction (after neo-adjuvant photon or proton therapy to minimise the risk of infection), reconstructing the pelvic ring with autogenous fibula strut graft which may be vascularised or non-vascularised, with or without osteosynthesis.
    SYMPTOMS & EXAMINATION
    Patients with primary bone tumours present principally with pain and swelling, with or without limitation of motion and reduced ability to bear weight. With pelvic tumours, particularly arising from the inner table, they may reach considerable size before causing symptoms leading to presentation. If a pelvic tumour has invaded the greater sciatic notch then motor and sensory radiculopathy can sometimes be evident. Often if the tumour involves the pubis, the extrinsic pressure on the femoral vein and lymphatics can lead to generalised oedema of the limb and thrombosis in the femoral vein should be excluded in these cases.
    When examine the patient specific features to investigate and document include the biopsy tract, previous scars (inguinal hernia repairs or caesareans), range of hip motion of hip, limb-length, neurovascular status, skin quality including previous scars and sinuses, abductor function, availability of local soft tissue flaps as required.
    IMAGING & INVESTIGATIONS
    Plain AP radiograph of the pelvis is required to delineate the size and location of the tumour as well as extra-osseous extension. Radiographs are assessed for the extracellular matrix deposition of the tumour be that osteoid (e.g. osteosarcoma), chondroid (e.g. chondrosarcoma) or fibrous (fibrosarcoma of bone) which hints at the diagnosis.
    Patients undergo biopsy to confirm the histological diagnosis. In our centre biopsies either occur in the operating theatre using a Jamshidi needle and fluoroscopy or CT guidance via a direct lateral approach. The positioning of the biopsy tract is crucial to ensure that is does not cross more than one anatomical compartment or compromise vital structures as the biopsy tract is excised en-bloc at the time of surgery. Typically the histological biopsy results take 7 to 10 days to be reported and are discussed at the sarcoma multi-disciplinary team (MDT) meeting comprising orthopaedic surgeons, radiologists, pathologists and oncologists. For pelvic tumours, easily excisable biopsy tracts include the anterior inferior iliac spine and the posterior superior iliac spine, but an individual approach is required in each case and should be planned by the surgeon who will undertake definitive resection.
    Prior to surgery patients are ‘staged’, which involves local staging of the effected bone (i.e. MRI scan of the pelvis including the hip joints) and distal staging to include CT chest and whole-body imaging e.g. bone scintigraphy, whole-body MRI or whole-body PET-CT, to exclude metastatic disease. If metastases are identified at the time of diagnostic staging this may influence the extent of surgical and systemic treatment but may not preclude surgical excision of the primary tumour; all of these details are considered at the sarcoma MDT when deciding upon the optimum treatment by all involved specialists. Although the British Sarcoma Group guidelines recommend whole-body staging of chondrosarcomas, evidence is now emerging to suggest this may not be necessary as the incidence of bone metastases is very low at diagnosis.
    Enneking and Dunham classified pelvic resections into: type I (ilium), type II (periacetabular), and type III resection (obturator). Resections involving the sacrum are referred as type IV. Achieving adequate surgical margins to ensure the tumour is excised-bloc is the guiding oncological principle to avoid local recurrence; local recurrence is often accompanied by metastasis and can only be controlled by en-bloc excision with wide surgical margins. Resection of a tumour from the pelvis often requires reconstruction of the large bone and soft-tissue defect depending upon the defect.

    ALTERNATIVE OPERATIVE TREATMENT
    For chondrosarcomas of the pelvis, alternatives to en-bloc excision do not yet exist. With the advent of genomics, IDH may in the future offer an adjuvant to surgery, and there are some reports from the US regarding the role of radiotherapy in pelvic chondrosarcoma, but this is not routinely offered elsewhere.
    NON-OPERATIVE MANAGEMENT
    For chondrosarcoma the principle treatment is en-bloc excision and reconstruction as these are relatively chemo- and radiotherapy insensitive tumours.
    For other primary pelvic bone tumours, patients typically receive pre-operative chemotherapy, then surgical resection and reconstruction followed by further post-operative chemotherapy. Some tumours, such as Ewing’s sarcoma, are relatively sensitive to radiotherapy (protons) and we prefer to give protons pre-operatively because there is some emerging evidence this has a survival advantage over post-op protons.
    CONTRAINDICATIONS
    If the patient was medically unfit to undergo major surgery or if the staging revealed that the disease had already spread to the lungs with a very poor prognosis then surgery may be contraindicated although palliative surgery to control pain may still be contemplated.

    Setup

    Whilst the patient is being anaesthetised the patient CT & MRI scans are uploaded to the navigation system (Stryker NAV3i) and the two scans are fused and registration points that can be identified intra-operatively are planned. We then plan multiple osteotomies as required to excise the bone tumour.
    Typically pelvic cases undergo combined epidural and spinal anaesthesia (Bupivacaine) using to achieve good post-operative pain relief and reduce peri-operative venous load to minimise blood loss. Urinary catheters, bowel preparation, central line and arterial cannulae are all mandatory. Prophylactic antibiotics (broad spectrum Fluxcloxacillin and Gentmicin, unless penicillin allergy) and tranexamic acid are also given immediately pre- and post-operatively.

    Operation – 1

    Pre-operative AP pelvic radiograph showing a radiodense lesion consistent with a possible osteochondroma arising from the left ileum.

    Pre-operative T2-weighted coronal MRI showing a chondrosarcoma arising from the osteochondroma of the lateral ileum(1). It has characteristically high-signal on these fluid sensitive sequences, with areas of low-signal giving a lobulated appearance.

    Axial T2-weighted MRI sequence showing that the tumour breaches the medial cortex of the ileum but lies with the iliacus muscle and gluteus medius muscle. These will need to be resected as surgical margins for an en-bloc resection of the chondrosarcoma.

    Coronal CT showing some calcification within the soft-tissue of the tumour indicating a chondrosarcoma.

    Position the patient in a floppy lateral position in order to access both anterior and posterior aspects of the pelvis. The patient is stabilised both anteriorly and posteriorly.A side support is placed in the thoracic region with a simple sandbag underneath the operative drapes anteriorly, near the abdomen, to prevent forward sliding of the patient intra-operatively.
    The contralateral leg may be strapped to the table to prevent a fall with adequate padding of all bony prominences to prevent neurovascular compression. Exclusion drapes are applied to isolate the limb and hemipelvis from umbilicus anteriorly to the midline of the sacrum posteriorly.

    The skin marking starts by identifying and marking palpable bony landmarks: Firstly, the greater trochanter (GT) is marked, secondly the anterior superior iliac spine (ASIS), followed by a curved marking along the iliac crest up to the posterior superior iliac spine (PSIS).Preoperative incision marking is performed along with isolation of the biopsy tract so as to ensure excision of the biopsy tract. Once the bony landmarks have been identified, connect the dots from the GT to the ASIS curving it along the iliac crest to the PSIS. The incision can be extended distally along the thigh or posteriorly along the sacrum based on the extent of dissection required.

    Pre-operatively the patient’s MRI & CT is loaded onto the navigation machine and the planes for the resection are planned. Anatomical points are chosen for registration of the patient’s anatomy to the CT model during the procedure. We have used the anterior superior iliac crest, the sciatic notch, the posterior superior iliac spine and the anterior inferior iliac spine because all can be reached during the procedure.

    Skin preparation and draping using Ioban incisional drapesThe skin is prepped with alcoholic chlorhexidine twice until dry and single use adhesive drapes are applied, isolating the hemipelvis from the midline anteriorly to the midline posteriorly and from the rib cage cranially to the distal thigh caudally. Incisional Ioban drapes are applied taking care to exclude the perineum.

    The skin incision runs from the greater trochanter to the anterior superior iliac spine curving along the iliac crest to the posterior superior iliac spine. The incision can be extended distally along the thigh or posteriorly along the sacrum based on the extent of dissection required. Skin and fasciocutaneous flaps are raised as a single layer to maintain perfusion to skin edges and optimise healing.

    Identify the deep fascia over the greater trochanterComplete the superficial dissection down to the deep fascia inline with the gently curved skin incision from the greater trochanter to the iliac crest.

    Incise the fascia lata posterior to the greater trochanter.Just posterior to the greater trochanter, an incision using cautery through the facia lata is used to enter the plane between the fascia and gluteus medius, inserting onto the trochanter. The silvery flash of vastus laterals beneath will be familiar to hip surgeons incising the facia when approaching the hip for routine arthroplasty. Beware if the patient has previously has hip surgery as this layer maybe adherent to the deeper layers.

    Incise the deep fascia between the trochanter and ASIS.The vertical limb of the question mark approach is raised in layers up to the level of the ASIS. The limb is held in abduction and subsequently the fascia lata is incised from the level of the greater trochanter up to the ASIS. There are no structures at risk during this step.

    Elevate the fasciocutaneous flap to identify the plane between sartorius and tensor fascia lata.In the anterior aspect of the incision, the skin and fasciocutaneous flap are raised and the plane between the sartorius and the tensor fascia lata (TFL) muscle is identified. This reveals the (GT) greater trochanter and the (GM) gluteus medius.

    Identify the gluteus maximus tendon.The (GMax) gluteus maximus tendon is a useful anatomical landmark. It is found on the posterior aspect of the proximal femur, inserting onto the femur beneath the silvery (VL) vastus lateralis.
    The sciatic nerve runs deep to the gluteus maximus tendon as it enters the posterior compartment of the thigh and lies within the intermuscular fat between the external rotators inserting onto the femur anteriorly and the gluteus maximus muscle posteriorly. Often it is identified by palpation in this layer only. The first perforating artery of the thigh, arising from profounda femoris, is reliably located immediately beneath the tendon.

    Divide the gluteus maximus tendon posterior to the femoral insertion.To mobilise the flap which is based upon the gluteal vessels release of the gluteus maximus can be cranial (off the posterior ileum) or caudal (off the femur). By dividing the gluteus maximus tendon off the posterior femur as it inserts posterior to the (VL) vastus lateralis, greater exposure and clearer identification of the correct plane is achieved to protect the inferior gluteal pedicle crucial for this approach. In order to protect the sciatic nerve and first perforator, divide the tendon over a curved artery clip using cautery lifting the tendon away from the nerve and vessel.

    Having divided the gluteus maximus tendon, identify the sciatic nerve.Having divided the gluteus maximus tendon, the exposure of the posterior proximal femur and (GT) greater trochanter with the inserting (GM) gluteus medius is dramatically improved. The (Sn) sciatic nerve is easily palpated running in the fat between the gluteus maximus muscle posteriorly and the (ERs) external rotator muscles anteriorly. From proximal to distal the structures released are piriformis, superior gemellus, obturator internus, inferior gemellus, obturator externus and quadratus femoris with the joint capsule beneath.

    The exposure is continued further proximally following exposure of the proximal femur.

    Identify the plane between sartorius and tensor fascia lata, which is a natural plane of cleavage seen after dividing the fascia over the Gluteii.Anteriorly, the dissection has reached a natural division between planes. Dividing the fascia over the gluteii leads to a junction between the (S) sartorius and (TFL) tensor facia lata muscles arising from the anterior superior iliac spine (ASIS). Sartorius is suppled by the femoral nerve and vessels; TFL is supplied by the superior gluteal nerve and vessels. This inter-nervous plane is very tight at this level approximately 2cm caudal to the ASIS.

    Having identified (S) sartorius and (TFL) tensor fascia lata muscles, the dissection is carried on with a slow curve onto the anterior superior iliac spine (ASIS)Now viewed anteriorly:
    It is continued posteriorly along iliac crest up towards the posterior superior iliac spine. At this level the dissection becomes sub-periosteal on the iliac crest to preserve muscle attachments for closure at the end of the procedure.

    Identify the (LFCN) lateral femoral cutaneous nerve of the thigh, (L2-3) which runs along psoas until it then passes under the (IL) inguinal ligament.It then runs through the lacuna musculorum and then over the sartorial muscle into the thigh, where it divides into an anterior and posterior branches. The inguinal ligament arises from the iliac crest and tuns to the pubic tubercle. Also shown are the fibres of the (EO) external oblique muscle of the abdominal wall inserting onto the iliac crest.

    Divide the abdominal wall off the iliac crestThe (AW) abdominal wall muscles are carefully dissected off the (IC) iliac crest in a single layer, using monopolar cautery taking the curvature of the illium into account. Initially dissect sub-periosteally along the iliac crest to identify the curvature of the ileum, then about 1cm posterior to the anterior super iliac spine (ASIS) where it is safest dissect using cautery through the muscle layer: forceps can be used to prevent the cautery damaging the peritoneum beneath, as shown, but the patient has been deliberately placed into a ‘floppy lateral’ position so that the peritoneum falls away from this step of dissection under gravity.

    Following dissection of the abdominal muscles from the anterior and middle third of the pelvis, carefully enter the retroperitoneum/retroperitoneal space by blunt dissection.Seen here is the fat indicating that the correct plane has been identified. Digitally sweep to ensure that the peritoneum is not in danger before continuing to divide the abdominal muscles. When sufficient space has been made, I prefer to cauterise onto my own finger so that the peritoneum is protected.

    Release the inguinal ligament off the ASISNow that the retroperitoneal space has been identified the femoral nerve can be identified as it heads towards the femoral sheath to enter the thigh. By releasing the inguinal ligament lateral to femoral nerve, off the ASIS, the femoral sheath and it’s contents (femoral artery and vein) are immediately retracted toward the pubis and away from the surgical field. Care is taken not to inadvertently damage the (LFCN) lateral femoral cutaneous nerve of thigh previously identified.

    This T1-weighted axial MRI at the level of the anterior super iliac spine (ASIS), highlights that the (CIV) common iliac vessels dividing into internal and external vessels at this level are a great distance away when releasing the inguinal ligament off the ASIS. Also annotated are the (P) psoas and (I) iliacus muscles which are easily differentiated radiologically at the level of the ASIS.

    Following release of the abdominal wall and inguinal ligament off the (IC) iliac crest, the (P) psoas muscle is easily identified just prior to it exiting the retroperitoneum and entering the thigh beneath the inguinal ligament.

    Operation – 2

    Retracting the psoas laterally, the ureter can be visualised running on the surface of the peritoneum toward the bladder. To confirm that it is indeed the ureter, gentle constriction with the Debakey’s forceps will demonstrate peristalsis. The ureter is at risk during pelvic surgery and appreciating it’s location throughout the operation is important to prevent inadvertent injury.
    The pelvic ureter crosses anteriorly to the iliac vessels at the bifurcation of the common iliac artery into the internal and external iliac arteries. The ureters then course out to the ischial spines before coursing medially to penetrate the base of the bladder. In females, the ureter runs posterior to the ovary and then deep to the broad ligament and through the cardinal ligament.

    The fascia overlying the iliac muscle is demonstrated here: a frequently used anatomical barrier and surgical margin for tumours arising in the pelvis.

    Identify the posterior superior iliac spineNow viewed posteriorly:
    The incision and dissection has continued along the iliac crest to the posterior superior iliac spine (PSIS). Dissection is deepened using cautery through the subcutaneous fat to the fascia over the iliac crest and spine.

    Sweep the fat overlying the deep fascia over the paraspinal muscles to identify where they insert onto the posterior iliac crest.
    As shown in the photograph, the distinctive fibres aid identification of this junction between the gluteus maximus and paraspinal muscles attached to the posterior iliac crest.
    The posterior superior iliac spine is labelled PSIS.

    Incise the deep fascia overlying the posterior iliac crestIncise this deep fascia overlying the posterior iliac crest to release the paralumbar muscles off the posterior ileum down to the most prominent point of the posterior superior iliac spine. In this case the tumour is very close to the deep surface of the gluteus maximus fascia and muscle which arise from the posterior fossa of the ileum, therefore is is safer to release this facia on the lumbar side of the posterior iliac crest.

    Divide the Iliolumbar ligament The iliolumbar ligament runs from the tip of the L5 transverse process to the posterior iliac crest and feels boney hard. This must be released to remove this part of the ileum. Divide the (ILL) iliolumbar ligament after passing a curved artery clip or finger beneath it under direct vision to avoid the valveless iliolumbar vein that runs immediately medial to the ligament and drains the L4&5 segments into the the common iliac vein, which can bleed severely if inadvertently divided.
    An elliptical skin incision over the biopsy tract at the PSIS can be seen in the photograph and will be excised en-bloc with the tumour.

    Superficial dissection is now complete, this photograph highlights why it is known as the question mark approach. The musculocutaneous flap that will now be elevated off the tumour involves the entire gluteus maximus from the trochanter to the sacrum as shown.

    Release the gluteal aponeurosisViewed from posteriorly:
    On the outer table of the anterior iliac crest, lateral to TFL, the (GA) gluteal aponeurosis and attachment of the (GMed) gluteus medius is released off the iliac crest from anterior to posterior. This allows the anterior portion of the flap to begin to be elevated off the iliac crest and gluteus medius.

    As the (GA) gluteal aponeurosis is released off the (IC) iliac crest, the fasciocutaneous flap is elevated off the (GM) gluteus medius as shown. The forceps are tucked into the plane of dissection which becomes easier to identify as the dissection continues.

    Identify the sciatic notchHaving released the (GA) gluteal aponeurosis off the anterior (IC) iliac crest and elevated the fasciocutaneous flap off the (Gmed) gluteus medius, the origin of the (GMax) gluteus maximus from the posterior ileum is encountered. When the flap is retracted, the sciatic nerve if easily traced up to the greater sciatic notch.

    Because this tumour is close to the dissection at this point I have come out of the gluteus maximus plane into the subcutaneous fat.
    This is to preserve an adequate surgical margin on the tumour, as the dissection continues posteriorly, because the tumour is sitting within the gluteus medius and covered by its overlying fascia.

    Identify the inferior gluteal pedicleNow that the myofasciocutaneous flap has been retracted off the posterior ileum and tumour, it is crucial to identify and preserve the vessels upon which the flap is based.
    Running within a layer of connective tissue on the deep surface of the (GMax) gluteus maximus, the inferior gluteal artery and vein supply this muscle and anastomose distally with the perforating thigh vessels, the first of which emerges deep to the gluteus maximus tendon as it inserts onto the femur. The inferior gluteal artery arises from the internal iliac artery and leaves the pelvis via the greater sciatic notch inferior to the piriformis and sciatic nerve.

    Next, superior to the greater sciatic notch (where there is no tumour) dissection using cautery down to bone just posterior to the (GMed) gluteus medius muscle allows the posterior ileum above the notch to be visualised.

    Place a Cobb elevator into the greater sciatic notch to protect the superior gluteal vessels and nerve exiting above the (P) pirifomis. Below the piriformis, the structures that exit the greater sciatic notch are the Pudendal nerve, nerve to Obturator Internus, Posterior femoral cutaneous nerve, Sciatic nerve, Inferior gluteal artery and nerve, nerve to Quadratus Femoris hence the mnemonic POPS IQ.

    Identify the superior gluteal pedicleThe superior gluteal pedicle is now clearly visualised: the superior gluteal vessels supply the (GMed) gluteus medius, minimus and TFL.

    The dissection of the posterior ileum and sciatic notch is now completed prior to tumour resection. Seen in this photograph are the (SN) sciatic nerve, (P) piriformis, (GMax) gluteus maximus, (GMed) gluteus medius, (GT) greater trochanter and (IGP) inferior gluteal pedicle.

    Attach the navigation receiverAttach the navigation: Insert two 15mm pins into the superior iliac crest. Attach the (NT) navigation tracker using the hexagonal screwdriver to tighten the bolts onto the two pins in the iliac crest.

    Use the (NP) navigation pointer to register the patient’s bone to the synchronised MRI & CT scan.Angle the tracker to face the receiver on the navigation machine facing the surgeon and anterior to the patient but outside of the laminar flow enclosure. The image here shows the pointer in the surgeon’s hand, which is positioned on the posterior ileum during registration, and the tracker attached to the iliac crest, both facing the navigation receiver.

    Using the navigation pointer, mark out with cautery the pre-operatively planned osteotomies around the tumour.This will involve sacrificing some of the gluteus medius and minimus arising from the outer table of the ileum as a safe surgical resection margin.

    Where possible, try to identify and preserve any tributaries of the superior gluteal pedicle supplying TFL, gluteus minimus and medius to minimise muscle necrosis post-operatively which could lead to infection and worse ambulatory function.

    Continue to mark the planned osteotomy planes using the navigation and cautery down to periosteum.

    Rehearse the angles of the osteotomies required to safely excise the tumour using the navigation pointer and the navigation screen. By cutting the bone using navigation we can preserve the ilioischial bar connecting the acetabulum and sacrum, thus avoiding the need for reconstruction of he pelvic ring.

    On the screen the planned osteotomies around the tumour marked yellow can be seen as red and blue lines, whilst the green line indicates the position of the navigation pointer in the surgeon’s hand.

    The curved osteotomy on the ileum can be clearly marked using cautery and the angles of the cuts rehearsed using the navigation pointer. The three slightly curved) osteotomies will cut the middle of ileum between the ASIS and PSIS but without resecting the ilio-ischial bar inferiorly which forms the superior roof of the greater sciatic notch.

    Using a 1.27mm oscillating saw blade the outer cortex of the ileum is cut along the navigation planned cautery lines.Having released the abdominal wall off the iliac crest earlier in the approach, the only structure deep to the bone is the iliacus muscle, a portion of which will need to be resected with the tumour as a surgical margin.
    An abdominal retractor can placed between iliacus and the peritoneum for protection if desired.

    Operation – 3

    Complete the osteotomies using multiple osteotomesThe controlled blow on the osteotomes allows the the inner cortex of the ileum, and the corner of the osteotomies, to be completed in a controlled fashion. Again protection medially can be used.

    Once the osteotomes are all in place, gentle leverage on all of the osteotomes will complete the osteotomy leaving only residual soft-tissue dissection medially to be performed.

    Lever the tumour containing portion of the ileum being resected posteriorly (i.e. out of the wound and towards the surgeon and camera in this photograph) using an osteotome to gain access to the inner table and the (I) iliacus muscle.

    As the (R) resection specimen rolls laterally out of the wound, divide the overlying (I) iliacus muscle to retain a medial soft-tissue resection margin over the tumour.

    Remove the specimen from the wound. Here we can see the inner cut surface of the ilium and overlying (I) iliacus muscle, the residual (IIB) ilio-ischial bar and the (IGP) inferno gluteal pedicle.

    The resected tumour with a good soft-time margin medially and laterally to the iliac blade. Adequate soft-tissue margins are crucial to minimise the risk of local recurrence according to recent literature:
    Stevenson JD, et al. the role of surgical margins in chondrosarcoma. EJSO 2018;44(9):1412-18. https://www.sciencedirect.com/science/article/pii/S0748798318311168
    The tissue is wrapped and sent fresh to the laboratory for the resection margins to be analysed by the socialist sarcoma histopathologist.

    The residual defect in the ileum for reconstruction. The origin of the anterior portion of (GM) gluteus medius and minimus beneath has been preserved as it arises from the (AI) anterior ileum. The lower part of the osteotomy has avoided resection of the (IIB) ilio-ischial bar.

    Here we can see the preserved (SGP) superior gluteal pedicle supplying the retained abductors of (GM) gluteus medius and minimus beneath. The (IGP) inferior pedicle supplying the (GMax) gluteus maximus and the myofasciocutaneous flap raised during the approach, plus the (Sn) sciatic nerve arising beneath (P) piriformis are also seen.

    Insert three bone anchorsA Mitek bone anchor (GII, Depuy) is tapped into the cut surface of (PI) posterior ileum until good grip is achieved. The O ethibond sutures have curved needles already attached. Repeat this step with two further bone anchors into the (AI) anterior ileum and (II) inferior ileum.

    Using the ethibond sutures from the bone anchors, the graftjacket is sutured into iliac defect at three corners.

    Drill holes into the residual ilium to allow trans-osseous suture attachment of the graftjacketFurther trans-osseous drill holes for the sutures to pass through are made using a 2.5mm drill around the periphery of the defect in the residual ileum. Using continuous ethibond sutures from the bone anchors, seal the grafjacket into the defect.

    Secure the periphery of the grafjacket using the drill holes to pass the firewire sutures. This ensures the graftjacket acts as a buttress to prevent peritoneal herniation through the defect as the iliacus muscle has been removed on the medial side.

    Here the inferior egg of the graftjacket has been sutured to the (IIB) and the anterior edge of the graftjacket is being sutured down to the residual (AI) anterior ileum.

    Begin the deep closure by approximating curves of the flap with 1.0 vicryl sutures. Here the fascia overlying the greater trochanter is approximated to the posterior gluteus maximus side. Don’t forget to reattach the gluteus maximus tendon to the posterior femur.

    Reattach abdominal wall to residual ileum and graftjacketUsing Lane’s soft-tissue holding forceps to grasp all the layers of the (AW) abdominal wall (superficial fascia, external oblique muscle, internal oblique muscle, transversus abdominis muscle, transversalis fascia) the abdominal wall is reattached to the (IC) iliac crest anteriorly and posteriorly using 1.0 PDS sutures. Where the crest has been excised, the abdominal wall is sutured to the superior age of the (GJ) graftjacket. The (GMax) gluteus maximus and flap is then sutured to the abdominal wall and iliac crest, covering the graftjacket.

    Skin closureAfter closing the wound in layers, ski clips are applied.

    Apply vacuum dressingAn incisional vacuum dressing is applied to the wound for seven days (at 100mmHg continuous pressure setting).

    Post-Operative AP pelvic radiograph showing preservation of the ilio-ischial bar thus avoiding fibula graft reconstruction of the pelvic ring. We would expect the residual ilio-ischial bar to hypertrophy over the next 12 months radiographically.The bone anchors are also visualised in the anterior posterior and inferior residual ileum, along with surgical clips along the question mark approach.

    Post Operative

    Bed rest 48 hours
    Protected weight bearing 3 months
    VTE prophylaxis: LMWH 28 days and TED stockings 6 weeks
    VAC dressing change after 7 days
    Removal of clips 14 days
    Histology results to new reviewed in bone sarcoma MDT when ready
    Standard high grade sarcoma surveillance: clinical review and Xray fo the local site and chest every 3 months for the first two years, then six monthly until year 5, then annually until year 10 post-operatively.

    Recommended Reading

    Partial iliac resections, in this case made possible due to navigated assisted surgery, have been shown by Laitinen et al. to have the best functional outcomes compared to total iliac resections with and without reconstruction (Laitinen MK, et al. Resection of the ileum in patients with a sarcoma. Bone Joint Journal 2017;99-B:538–43. https://online.boneandjoint.org.uk/doi/abs/10.1302/0301-620X.99B4.BJJ-2016-0147.R1), although the partial resection group had the highest risk of local recurrence. Therefore, as ever in oncology surgery, the balance between oncological outcomes and functional loss must be explored by surgeons with patients pre-operatively, however achieving wide surgical margins remains the guiding principle.
    The use of navigation in pelvic oncology surgery has following advantages: Optimal surgical bone margins, reduction in operative time, beneficial in complex pelvic or peri-acetabular resections and more accurate implant or allograft implantation and reconstruction. However, navigation is expensive, takes time to prepare and setup and is associated with a learning curve as with all new techniques in surgery (Morris G, et al. Navigation in Musculoskeletal Oncology: an Overview. Indian J Orthop 2018 52(1): 22–30. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5791227/). Despite promising early results with navigation assisted surgery, local recurrence has remained a problem in the longer-term and we advise against compromising resection to preserve function, and encourage surgeons to reduce local recurrence by prioritising wide resection margins of the tumour (Nandra R, et al. Long-term outcomes after an initial experience of computer navigated resection of primary pelvic and sacral tumours: soft-tissue margins must be adequate to reduce local recurrences. Bone Joint J 2019;101-B:484–490. https://online.boneandjoint.org.uk/doi/abs/10.1302/0301-620X.101B4.BJJ-2018-0981.R1).
    Overall ten year survival for axial and appendicular chondrosarcoma is approximately 70%. The incidence of local recurrence is 26% and metastasis 32% (Fiorenza F, et al. Risk factors for survival and local control in Chondrosarcoma of bone.J Bone Joint Surg [Br] 2002;84-B:93-9. https://pdfs.semanticscholar.org/b0b7/d284cd20ce1bdc6b705eb2f571c465c65e68.pdf)
    Independent risk factors predictive of survival include extracompartmental spread, development of local recurrence and high histological grade. Independent risk factors for local recurrence include inadequate surgical margins and tumour size greater than 10 cm. Surgical excision with an oncologically wide margin provides the best prospect both for cure and local control in these patients. The challenge is distinguishing low grade from high grade tumours on pre-operative biopsy; recently it has been shown that histological grade cannot be accurately pre-determined with biopsy due to sampling error (Laitinen MK, et al. The role of grade in local recurrence and the disease specific survival in chondrosarcomas. Bone Joint J 2018;100-B:662–6. https://online.boneandjoint.org.uk/doi/abs/10.1302/0301-620X.100B5.BJJ-2017-1243.R1). Consequently it is recommended that any pelvic chondrosarcoma should undergo surgery aiming to achieve wide resection margins due to the high chance that a low grade tumour turns out to be a high grade tumour once resected and the whole of the tumour has been histopathologically assessed (Bus, M, et al. Conventional primary central chondrosarcoma of the pelvis. J Bone J Surg (Am)2018;100:316-25. https://dl.uswr.ac.ir/bitstream/Hannan/35979/1/2018%20AJBJS%20Volume%20100%20Issue%205%20March%20%286%29.pdf).
    Previous research has demonstrated that the optimum surgical margin (ie the closest distance between the tumour and cut surface of the specimen) is 4mm in appendicular chondrosarcomas, beyond which a greater surgical margin has no improvement in local recurrence, which determines survival in high grade tumours (Stevenson JD, et al. the role of surgical margins in chondrosarcoma. EJSO 2018;44(9):1412-18. https://www.sciencedirect.com/science/article/pii/S0748798318311168). Recent and as yet unpublished local research has shown that a minimum surgical margin of 2mm is required to minimise the risk of local recurrence and optimise survival chances in pelvic chondrosarcoma resections.
    If chondrosarcoma patient suffer local recurrence, the survival of the patient can be influenced if they undergo further excision achieving wide resection margins (Laitinen MK, et al. Locally recurrent chondrosarcoma of the pelvic and limbs can only be controlled by wide excision. Bone Joint J 2019;101-B:266–271. https://online.boneandjoint.org.uk/doi/abs/10.1302/0301-620X.101B3.BJJ-2018-0881.R1).




    Reference

    • orthoracle.com

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