Enrico Martin

267 Morbidity and function loss after resection of MPNST Discussion This study found that postoperative motor and sensory deficits are common morbidities after resection of MPNSTs. In patients who presented with motor or sensory deficits, these morbidities will likely persist after resection, but not in all cases. MPNSTs originating from major nerves were commonly resected completely resulting in major deficits. NF1 patients, large and deep-seated tumors were at an increased risk for postoperative deficits, more so for MPNSTs originating in the brachial plexus and pelvic area. Surgical treatment of MPNST In general, MPNSTs are ideally resected with wide margins. 5,6,18,19 Nonetheless, MPNSTs recur relatively frequently even when R0 margins are obtained. 2,20,21 When an MPNST arises from a major nerve, achieving microscopically free margins requires the resection of the nerve; in plexal MPNSTs, the resection of adjacent nerves may be required. Performing nerve-sparing procedures may be possible in some cases as reflected in our series, but will likely result in R1 resections. However, when performing resections with planned microscopic positive margins in combination with radiotherapy, local recurrence rates do not differ from achieving clear surgical margins. 22,23 R1 resections have also not been proven to affect survival in MPNSTs. 3,5,24 Nonetheless, a recent survey showed that many surgeons operating on MPNSTs are hesitant to perform less extensive resections regardless of surgical subspecialty. 25 Use of functional reconstructions in MPNST Ideal reconstructive strategies depend on several factors including patient age, exact functional deficits, the need for soft tissue coverage, and available donors for nerve and tendon transfers. As prognosis remains poor in MPNSTs, oncological treatment should be prioritized. However, with median survival ranging between 5-8 years in localized disease, 3–5 patients may live a significant part of their remaining life with substantial morbidity and less independence in activities of daily living (ADL). This is of importance in pediatric patients with MPNSTs who have a better prognosis compared to adults and whose survival has improved the last decades. 26,27 Considering postoperative function early on in a multidisciplinary team can improve patient selection for function preservation and functional reconstruction planning. Fortunately, not all MPNSTs will result in functional deficits or in deficits that require reconstruction. One smaller study found a motor deficit rate of 30%, 28 which is in line with the rate found in this study of any surgically resected MPNST. Functional reconstructions are unfortunately not routinely incorporated in STS treatment. 11–13 Systematic reviews have shown that functional outcomes may be satisfactory after the resection of extremity STS with the majority of cases recovering at least M3 muscle grade and high functional scores, despite multimodal therapy even for nerve reconstructions. 13,14 This can also be concluded from cases presented in this study who would otherwise have M0 deficits. 11