Peripheral nerve considerations in the management of extremity soft tissue sarcomas

Extremity and Truncal Soft Tissue Sarcoma: Risk Assessment and Multidisciplinary Management

Extremity and truncal soft tissue sarcomas are a heterogeneous group of rare cancers that arise from mesenchymal tissues. Hence, the adoption of tailored risk assessment and prognostication tools plays a crucial role in optimizing the decision-making for which of the many possible treatment strategies to select. Management of these tumors requires a multidisciplinary strategy, which has seen significant development in recent decades. Surgery has emerged as the primary treatment approach, with the main goal of achieving microscopic negative tumor margins. To reduce the likelihood of local recurrence, loco-regional treatments such as radiation therapy and isolated limb perfusion are often added to the treatment regimen in combination with surgery. This approach also enables surgeons to perform limb-sparing surgery, particularly in cases where a positive tumor margin is expected. Chemotherapy may also provide a further benefit in decreasing the probability of local recurrence or reducing distant metastasis in selected patients. Selecting the optimal treatment strategy for these rare tumors is best accomplished by an experienced multi-disciplinary team.

Immediate tendon transfer for functional reconstruction of a dorsal forearm defect after sarcoma resection

In the treatment of sarcoma, the reconstructive surgeon must consider not only limb salvage but also functional reconstruction. The aim of this study was to evaluate a functional reconstruction of a dorsal forearm defect after sarcoma resection using immediate tendon transfer. Patients who underwent reconstruction of a dorsal forearm defect after sarcoma resection with an immediate tendon transfer between 1997 and 2019 at our hospital were included in this retrospective study. Patient demographics, tumor characteristics, surgical characteristics and functional outcomes were examined. Nine patients were included in this study. Tendon transfer of the flexor carpi radialis (FCR) or the flexor carpi ulnaris (FCU) to the extensor digitorum communis (EDC), the brachioradialis (BR) to the EDC, and the palmaris longus (PL) tendon to the extensor pollicis longus (EPL) was performed in seven, two and five patients, respectively. Seven patients underwent reconstruction using a free flap. Neither anastomosis complications nor infections were encountered. Partial flap necrosis and donor site dehiscence were seen in one case each. The mean distal interphalangeal (DIP), proximal interphalangeal (PIP) and metacarpophalangeal (MP) joint active extension were 4.4°, 6.1° and 11.1° postoperatively. The mean Musculoskeletal Tumor Society (MSTS) score was 26. Immediate tendon transfers of the FCR or the FCU to the EDC and the PL tendon to the EPL can be considered an optimal functional reconstruction of a dorsal forearm defect after sarcoma resection.

Surgical considerations when reporting MRI studies of soft tissue sarcoma of the limbs

Soft tissue sarcomas (STS) are rare tumours that require prompt diagnosis and treatment at a specialist centre. Magnetic resonance imaging (MRI) has become the modality of choice for identification, characterisation, biopsy planning and staging of soft tissue masses. MRI enables both the operating surgeon and patient to be optimally prepared prior to surgery for the likelihood of margin-negative resection and to anticipate possible sacrifice of adjacent structures and consequent loss of function. The aim of this review is to aid the radiologist in performing and reporting MRI studies of soft tissue sarcomas, with particular reference to the requirements of the surgical oncologist.

Use of negative pressure wound therapy as an adjunct to the treatment of extremity soft-tissue sarcoma with ulceration or impending ulceration

Major wound complications of the extremities, following wide tumor resection and reconstruction for soft-tissue sarcomas (STSs), remain a challenge for limb-sparing surgery. Furthermore, STSs with ulceration or impending ulceration predispose patients to an increased risk of post-operative infection. The present study was conducted to assess the efficacy of negative pressure wound therapy (NPWT) in preventing wound complications associated with surgical treatment of STSs with ulceration or impending ulceration, in patients treated between February 2012 and January 2013. A total of 5 patients, with a mean age of 48 years (range, 24-68 years), were enrolled in the present study. The diagnoses consisted of undifferentiated pleomorphic sarcoma (n=2), leiomyosarcoma (n=1), synovial sarcoma (n=1) and epithelioid sarcoma (n=1). According to American Joint Committee on Cancer criteria, 3 cases were stage III tumors, and the remaining 2 cases were of stages IIA and IIB, respectively. A total of 3 patients exhibited ulceration at diagnosis, and the remaining patients demonstrated impending ulceration. The mean wound area following wide resection of the tumor was 73 cm² (range, 45-110 cm²). A continuous suction mode, with pressures measuring -200 to -300 mmHg, was used for 7-10 days on the soft-tissue defects as preparation for wound closure. Soft-tissue reconstruction included muscle flaps (n=2) and skin grafts (n=5). No major wound complications occurred. Post-operative functional and cosmetic outcomes were acceptable. A single patient demonstrated local recurrence 12 months after surgery and re-excision of the tumor was performed. All patients remained alive at the conclusion of follow-up, with a mean follow-up time of 26 months (range, 12-36 months). The present study demonstrated that NPWT is effective and safe when used as an adjunct to wound closure following resection of extremity STS with ulceration/impending ulceration.

Peripheral nerve tractography in soft tissue tumors: a preliminary 3-tesla diffusion tensor magnetic resonance imaging study

INTRODUCTION

This diffusion tensor magnetic resonance imaging (DTI) study aimed to clarify the relationship of peripheral nerves and soft tissue tumors (STTs) in 3D to optimize subsequent treatment.

METHODS

Twenty-six consecutive STT patients (histologically malignant, n=10; intermediate, n=3; and benign, n=13) underwent 3-Tesla MRI using an echoplanar DTI sequence. Deterministic tractography was performed. Fractional anisotropy (FA) values were measured within peritumoral and distant regions of interest.

RESULTS

Tractography depicted the 3D course of the sciatic (n=12), femoral (n=2), tibial (n=7), fibular (n=2), median (n=1), musculocutaneous (n=1), and ulnar (n=1) nerves in a regular (n=8 of 18, 44.4%) or thinned (n=7 of 18, 38.9%) fashion. The lowest peritumoral FA values, abrupt thinning, and/or complete discontinuity of trajectories were found in 2 cases with histologically proven tumoral nerve infiltration.

CONCLUSIONS

DTI clarifies the 3D topography between major peripheral nerves and STTs and may be helpful in the assessment of peripheral nerve infiltration by malignant tumors.

Upper extremity considerations for oncologic surgery

It was estimated that more than 3000 people would be diagnosed with a primary bone or joint malignancy and more than 11,000 people would be diagnosed with a soft tissue sarcoma in 2013. Although primary bone and soft tissue tumors of the upper extremity are infrequent, it is imperative that the clinician be familiar with a systematic approach to the diagnosis and treatment of these conditions to prevent inadvertently compromising patient outcome. With advances in chemotherapy, radiotherapy, tumor imaging, and surgical reconstructive options, limb salvage surgery is estimated to be feasible in 95% of extremity bone or soft tissue sarcomas.

Planned preservation surgery for soft tissue sarcomas adjacent to critical structures

BACKGROUND

Whether to preserve or sacrifice critical structures (bone, major vessels and major nerves) adjacent to soft tissue sarcomas is still controversial. Referring to characteristic imaging and intraoperative findings, we perform planned preservation surgery for these critical structures. The aim of this study was to investigate the clinical outcome of soft tissue sarcomas adjacent to critical structures and to validate this procedure.

METHODS

Of 202 cases of soft tissue sarcomas surgically treated at our department of orthopedic surgery from 2004 to 2010, 57 cases (28 %) whose tumors were adjacent to the critical structures were studied. There were 36 men and 21 women. In 32 cases critical structures were preserved, and in 25 resected together with the tumor. The oncological outcome and histological surgical margin were analyzed.

RESULTS

The overall survival and local recurrence-free survival rates at 5 years were 75.9 and 83.2 %. In 26 of the 32 (81 %) preserved cases histologically the surgical margin was negative, and in 17 (53 %) radiotherapy could be avoided. Neither overall survival (p = 0.9669) nor local recurrence-free survival (p = 0.7819) differed significantly between two groups.

CONCLUSIONS

When soft tissue sarcomas are located adjacent to bone or major vessels, by meticulously detaching the periosteum or neurovascular sheath referring to characteristic imaging and intraoperative findings, a histologically negative surgical margin can be achieved in the majority, allowing avoidance of postoperative radiotherapy. Planned preservation surgery provided no significant adverse effect on survival or local recurrence rates, validating this procedure.

The effects of irreversible electroporation (IRE) on nerves

Background

If a critical nerve is circumferentially involved with tumor, radical surgery intended to cure the cancer must sacrifice the nerve. Loss of critical nerves may lead to serious consequences. In spite of the impressive technical advancements in nerve reconstruction, complete recovery and normalization of nerve function is difficult to achieve. Though irreversible electroporation (IRE) might be a promising choice to treat tumors near or involved critical nerve, the pathophysiology of the nerve after IRE treatment has not be clearly defined.

Methods

We applied IRE directly to a rat sciatic nerve to study the long term effects of IRE on the nerve. A sequence of 10 square pulses of 3800 V/cm, each 100 µs long was applied directly to rat sciatic nerves. In each animal of group I (IRE) the procedure was applied to produce a treated length of about 10 mm. In each animal of group II (Control) the electrodes were only applied directly on the sciatic nerve for the same time. Electrophysiological, histological, and functional studies were performed on immediately after and 3 days, 1 week, 3, 5, 7 and 10 weeks following surgery.

Findings

Electrophysiological, histological, and functional results show the nerve treated with IRE can attain full recovery after 7 weeks.

Conclusion

This finding is indicative of the preservation of nerve involving malignant tumors with respect to the application of IRE pulses to ablate tumors completely. In summary, IRE may be a promising treatment tool for any tumor involving nerves.