Pictorial review of leg muscle compartments: anatomy, lesions within and management approaches.

Transcription

1 Pictorial review of leg muscle compartments: anatomy, lesions within and management approaches. Poster No.: P-0065 Congress: ESSR 2015 Type: Educational Poster Authors: A. Shah, R. Botchu, R. Ashford, W. J. Rennie ; Leicester/UK, Kettering/UK Keywords: Anatomy, Musculoskeletal soft tissue, Interventional non-vascular, MR, Ultrasound, Diagnostic procedure, Biopsy, Technical aspects, Cancer, Education and training DOI: /essr2015/P-0065 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 34

2 Learning objectives 1. Anatomy of the leg compartments 2. Radiological considerations: which modality? 3. Do's and don'ts of lesion biospy 3. Pictorial review of percutaneous biopsy approches. Page 2 of 34

3 Background The leg comprises of four osseofascial compartments by: interosseous membrane of the leg, transverse intermuscular septum & the anterior intermuscular (crural) septum 1. Anterior: muscular tibialis anterior extensor hallucis longus extensor digitorum longus neurovascular deep peroneal nerve anterior tibial vessels 2. Lateral: muscular peroneus longus peroneus brevis neurovascular superficial peroneal nerve 3. Superficial Posterior: muscular gastrocnemius plantaris soleus neurovascular sural nerve 4. Deep Posterior: muscular Page 3 of 34

4 tibialis posterior flexor hallucis longus flexor digitorum longus popliteus neurovascular tibial nerve posterior tibial vessels Fig. 1: MRI axial with highlighted areas demonstrating the compartments of the leg. Anterior (green), lateral (purple), superficial posterior (blue), deep posterior (red). Black dotted arrow: Anterior tibial neurovascular bundle Green dotted arrow: Posterior tibial neurovascular bundle Red dotted arrow: common peroneal nerve coursing around the neck of fibula Purple dotted arrow: deep peroneal nerve at the deep surface of peroneus longus Orange dotted arrow:medial sural nerve References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 4 of 34

5 Benign and aggressive lesions can be found in the leg and sound knowledge of the anatomy and possible origin of the lesion helps narrow the differential Depending on the lesion location, different imaging modalities are utilised to interrogate and characterise the mass. Accurate assessment of the lesion and its relation to vital structures, such as the neurovascular bundle, underlying bone and its location in terms of other muscle compartments must be made. The management of the lesion can be conservative or surgical depending on the nature of the lesion. Soft-tissue sarcomas and metastatic tumors of the popliteal fossa and posterior compartments of the leg have traditionally been treated with above-knee amputation. The major considerations governing the decision to amputate were: the proximity to the neurovascular bundle and extent of soft-tissue involvement and resection. Expected poor wound healing as the result of the extensive resection, compromised blood supply to the surgical site, and the frequent need to administer adjuvant radiation therapy. For the radiologist planning to biopsy a suspicious musculoskeletal lesion, consultation with the referring orthopaedic surgeon is recommended in order to jointly select an appropriate percutaneous biopsy approach. This will minimise the risk of tumour seeding and allow complete resection of the biopsy tract and scar at the time of surgical resection without jeopardising a potential limb-sparing procedure. Page 5 of 34

6 Images for this section: Fig. 1: MRI axial with highlighted areas demonstrating the compartments of the leg. Anterior (green), lateral (purple), superficial posterior (blue), deep posterior (red). Black dotted arrow: Anterior tibial neurovascular bundle Green dotted arrow: Posterior tibial neurovascular bundle Red dotted arrow: common peroneal nerve coursing around the neck of fibula Purple dotted arrow: deep peroneal nerve at the deep surface of peroneus longus Orange dotted arrow:medial sural nerve Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 6 of 34

7 Imaging findings OR Procedure Details Anatomy Fig. 2: Proximal lower leg: MRI axial image with highlighted compartments: Anterior (green), lateral (purple), superficial posterior (blue), deep posterior (red). Structures to avoid during biopsy: Tibial tubercle (star), anterior (black dotted arrow) and posterior (green dotted arrow) tibial neurovascular bundles (in anterolateral and posteromedial leg, respectively), peroneal neurovascular bundle in deep posterior compartment of calf (black solid arrow), deep peroneal nerve at the deep surface of peroneus longus (white curved arrow), common peroneal nerve (black curved arrow) coursing around the neck of fibula References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 7 of 34

8 Fig. 3: Distal leg anatomy: Axial MR demonstrating the compartmental anatomy of the distal leg. Anterior (green), lateral (purple), superficial posterior (dark blue), deep posterior (light blue). Structures to avoid during biopsy: Anterior (yellow circle) and posterior (orange circle) tibial neurovascular bundles Peroneal neurovascular bundle (red circle) Deep peroneal nerve at the deep surface of the peroneus longus muscle (curved blue arrow) References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Modalities: Ultrasound has been shown to be an effective triage tool (Lakkaraju A et al) and in conjunction with MRI (Gielen JL et al, Mutlu H et al), most soft tissue tumours can be characterised with a high degree of sensitivity and specificity as either benign, indeterminate or malignant. Management including biopsy must be decided through a sarcoma MDT (Shah et al). Close collaboration with a multidisciplinary team that consists of a surgical oncologist, oncologist, and musculoskeletal (MSK) pathologist is vital. Page 8 of 34

9 Surgical management depends on the lesion location, number or compartments it crosses and its proximity to the neurovascular bunble. Consideration to neoadjuvant chemoradiotherapy must be made by the MDT to down grade tumours. Percutaneous biopsies: Image-guided musculoskeletal (MSK) biopsies are safe and effective procedures yielding diagnostic accuracies up to 97%. Any MSK lesion that can be confidently diagnosed as ''benign'' based on radiological and clinical information (e.g., ''Do not touch lesions'') should not be biopsied (Helms). Unless proven otherwise, all lesions should be treated as if they were sarcomas with the intent to perform curative resection. Biopsy should be delayed until all necessary imaging is available to accurate stage and manage patient. Bone biopsies should be performed under CT guidance ideally with general anaestheisa. Soft tissue biopsies can often be performed under ultrasound guidance with local anaesthesia. Placement of the biopsy tract must be chosen carefully so that it may be later removed en bloc with the lesion. The approach for the radiologist performing a closed percutaneous needle biopsy should be along the course of an incision the surgeon may use to safely approach the lesion without jeopardising skin or soft tissue needed for later flap coverage or closure. In general, incisions for open biopsy of the extremities are made in longitudinal fashion, as excision of a transverse incision may require significant flap coverage and risk of skin necrosis. Tips: In general, avoiding crossing more than one anatomic compartment is important in preserving a limb-salvage surgical plan, as the needle track is at risk of seeding tumor cells (Davies NM et al) the needle track is usually resected, the tissues that lie along the track will be removed. It is therefore important to minimise compartmental tumoral contamination to allow as minimal resection as possible. Biopsy with ultrasound allows dynamic visualisation of the needle - under no circumstances should the biopsy needle be deployed without confirmation of the needle tip. Page 9 of 34

10 Fig. 4: Longitudinal ultrasound of a soft tissue mass with the biopsy needle advanced (highlighted) in the mass. Biopsy should only be obtained when the needle tip is visualised. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 10 of 34

11 Fig. 5: Axial CT. Preparation for a biopsy is key. All relevant imaging must be reviewed. MDT decision for biopsy must be obtained so that the appropriate entry point is selected. The patient should be appropriately consented and coagulation profile checked. We perform bone biopsies under general anaesthesia. The patient is positioned in the optimal position for anaesthesia and biopsy. A grid is placed on the skin to allowing marking of the skin for needle entry point. The distance is calculated to be able to select the appropriate biopsy needle. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 11 of 34

12 Fig. 6: Axial CT with the biopsy needle in situ Care must be taken not to cross anatomic compartments.. The biopsy needle is ideally placed just distal to the lesional margin. The red arrows show incorrect biopsy entry points that would breach different anatomical compartments. The orange arrow show an alternative entry point, however, this would be technically more challenging as the risk of penetrating the posterior cortex and potential contamination with excessive force. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 12 of 34

13 Fig. 7: Axial CT and sagittal PD FS MRI demonstrating a chondoid lesion posteriorly in the tibia. What biopsy approach should be taken? References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 13 of 34

14 Fig. 8: Axial CT during biopsy of the posterior tibial lesion seen in Figure 7. Anterior approach, slightly medial to the midline - avoid the patellar tendon (outlined in yellow). This will also be the surgical incisional approach during surgery and so ensuring the needle tract is also incised. There is no medial compartment in the lower leg so this approach will not contaminate another compartment. Orange arrow indicates an alternative approach that could have taken. Red arrows indicate inappropriate approaches. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 14 of 34

15 Fig. 9: Axial CT on soft tissue windows demonstrates an intramedullarly lesion in the tibia. Red arrows demonstrate inappropriate biopsy approaches which is followed would contaminate multicompartments. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 15 of 34

16 Fig. 10: Axial CT demonstrating the correct approach required to biopsy an intramedullarly lesion seen in Figure 9. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 16 of 34

17 Fig. 11: Axial PD FS of the proximal tibia. The red arrows indicate incorrect biopsy approaches. Entry from a direct anterior approach risks injuring the tibial tuberosity and patellar tendon attachment. Green arrow indicates a correct approach for this lesion without multicompartmental contamination. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 17 of 34

18 Fig. 12: Axial TI MRI image of the lower leg demonstrates an expansile intramedullary cystic lesion with multiple fluid-fluid levels. Areas of high T1 signal fluid is in keeping with haemorrhage. Imaging features are suggestive of an aneurysmal bone cyst. Biopsy approaches which are safe are indicated by the green narrows. Red arrows demonstrate inappropriate approaches. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 18 of 34

19 Fig. 13: A large soft tissue lesion circumferentially encasing the fibula on this PD FS MRI. Correct entry point would be laterally. The anterior tibialis muscle is already involved by the lesion so can be crossed, however the red arrows show incorrect entry points as they would cause multicompartmental contamination. References: Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 19 of 34

20 Images for this section: Fig. 2: Proximal lower leg: MRI axial image with highlighted compartments: Anterior (green), lateral (purple), superficial posterior (blue), deep posterior (red). Structures to avoid during biopsy: Tibial tubercle (star), anterior (black dotted arrow) and posterior (green dotted arrow) tibial neurovascular bundles (in anterolateral and posteromedial leg, respectively), peroneal neurovascular bundle in deep posterior compartment of calf (black solid arrow), deep peroneal nerve at the deep surface of peroneus longus (white curved arrow), common peroneal nerve (black curved arrow) coursing around the neck of fibula Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 20 of 34

21 Fig. 3: Distal leg anatomy: Axial MR demonstrating the compartmental anatomy of the distal leg. Anterior (green), lateral (purple), superficial posterior (dark blue), deep posterior (light blue). Structures to avoid during biopsy: Anterior (yellow circle) and posterior (orange circle) tibial neurovascular bundles Peroneal neurovascular bundle (red circle) Deep peroneal nerve at the deep surface of the peroneus longus muscle (curved blue arrow) Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 21 of 34

22 Fig. 4: Longitudinal ultrasound of a soft tissue mass with the biopsy needle advanced (highlighted) in the mass. Biopsy should only be obtained when the needle tip is visualised. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 22 of 34

23 Fig. 5: Axial CT. Preparation for a biopsy is key. All relevant imaging must be reviewed. MDT decision for biopsy must be obtained so that the appropriate entry point is selected. The patient should be appropriately consented and coagulation profile checked. We perform bone biopsies under general anaesthesia. The patient is positioned in the optimal position for anaesthesia and biopsy. A grid is placed on the skin to allowing marking of the skin for needle entry point. The distance is calculated to be able to select the appropriate biopsy needle. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 23 of 34

24 Fig. 6: Axial CT with the biopsy needle in situ Care must be taken not to cross anatomic compartments.. The biopsy needle is ideally placed just distal to the lesional margin. The red arrows show incorrect biopsy entry points that would breach different anatomical compartments. The orange arrow show an alternative entry point, however, this would be technically more challenging as the risk of penetrating the posterior cortex and potential contamination with excessive force. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 24 of 34

25 Fig. 7: Axial CT and sagittal PD FS MRI demonstrating a chondoid lesion posteriorly in the tibia. What biopsy approach should be taken? Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 25 of 34

26 Fig. 8: Axial CT during biopsy of the posterior tibial lesion seen in Figure 7. Anterior approach, slightly medial to the midline - avoid the patellar tendon (outlined in yellow). This will also be the surgical incisional approach during surgery and so ensuring the needle tract is also incised. There is no medial compartment in the lower leg so this approach will not contaminate another compartment. Orange arrow indicates an alternative approach that could have taken. Red arrows indicate inappropriate approaches. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 26 of 34

27 Fig. 9: Axial CT on soft tissue windows demonstrates an intramedullarly lesion in the tibia. Red arrows demonstrate inappropriate biopsy approaches which is followed would contaminate multicompartments. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 27 of 34

28 Fig. 10: Axial CT demonstrating the correct approach required to biopsy an intramedullarly lesion seen in Figure 9. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 28 of 34

29 Fig. 11: Axial PD FS of the proximal tibia. The red arrows indicate incorrect biopsy approaches. Entry from a direct anterior approach risks injuring the tibial tuberosity and patellar tendon attachment. Green arrow indicates a correct approach for this lesion without multicompartmental contamination. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 29 of 34

30 Fig. 12: Axial TI MRI image of the lower leg demonstrates an expansile intramedullary cystic lesion with multiple fluid-fluid levels. Areas of high T1 signal fluid is in keeping with haemorrhage. Imaging features are suggestive of an aneurysmal bone cyst. Biopsy approaches which are safe are indicated by the green narrows. Red arrows demonstrate inappropriate approaches. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 30 of 34

31 Fig. 13: A large soft tissue lesion circumferentially encasing the fibula on this PD FS MRI. Correct entry point would be laterally. The anterior tibialis muscle is already involved by the lesion so can be crossed, however the red arrows show incorrect entry points as they would cause multicompartmental contamination. Radiology, NHS Trust, University Hospitals of Leicester - Leicester/UK Page 31 of 34

32 Conclusion We have highlighted the importance of a detailed understanding of compartmental anatomy when approaching a patient with a lower extremity musculoskeletal mass. We have described the interventional/surgical management of such lesions. Page 32 of 34

33 References Davies NM, Livesley PJ, Cannon SR. Recurrence of an osteosarcoma in a needle biopsy track. J Bone Joint Surg Br 1993;75: Gielen JL, De Schepper AM, Vanhoenacker F, Parizel PM, Wang XL, Sciot R et al. Accuracy of MRI in characterization of soft tissue tumors and tumor-like lesions. A prospective study in 548 patients. Eur Radiol Dec;14(12): Helms CA. ''Don't touch'' lesions. In: Fundamentals of Skeletal Radiology. 2nd ed. Philadelphia: WB Saunders; 1995:56-77 Lakkaraju A, Sinha R, Garikipati R, Edward S, Robinson P. Ultrasound for initial evaluation and triage of clinically suspicious soft-tissue masses. Clin Radiol. 2009;64(6): Mutlu H, Silit E, Pekkafali Z, Basekim CC, Ozturk E, Sildiroglu O et al. Soft-tissue masses: Use of a scoring system in differentiation of benign and malignant lesions. Clin Imaging (1): Shah A, Botchu R, Ashford RU, Rennie WJ. Diagnostic triage for sarcoma: an effective model for reducing referrals to the sarcoma multidisciplinary team. Br J Radiol May;88(1049): Page 33 of 34

34 Personal Information Dr Amit Shah, Department of Radiology, Royal Orthopaedic Hospital, Birmingham B21 3AP, UK Dr Rajesh Botchu, Department of Radiology, Royal Orthopaedic Hospital, Birmingham B21 3AP, UK Mr Robert U Ashford, Deprtment of orthopaedics, Leicester Royal Infirmary, Infirmary Square, LE1 5WW Dr Winston Rennie, Deprtment of Radiology, Leicester Royal Infirmary, Infirmary Square, LE1 5WW Page 34 of 34