Philippe Lim
email: lim.philippe@chu-amiens.fr

Marie Fechtenbaum

Patrice Fardellone

Vincent Goëb

Infiltration épidurale par corticostéroïdes compliquée d'un hématome sous dural : un nouveau cas

ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

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Infiltration épidurale par corticostéroides compliquée d'un hématome sous dural : description d'un fait clinique

Philippe Lim a, Marie Fechtenbaum b , Patrice Fardellone a , Vincent Goëb a a Service de Rhumatologie CHU Amiens-Picardie, place Victor Pauchet, 80054 Amiens cedex, France b Service de rhumatologie, hôpital Cochin, AP-HP, 75014 Paris, France Résumé Introduction Les infiltrations épidurales de corticostéroides constituent un traitement classique des lomboradiculalgies. La description d'événements neurologiques grave par la Food and Drug Administration (FDA) conduit à se poser la question du bénéfice-risque de cette pratique.

Cas clinique

Une femme caucasienne, âgée de 55 ans, est hospitalisée pour la prise en charge d'une lombosciatique de trajet S1 droite. Au cours de l'hospitalisation, sont réalisées à 48 heures d'intervalle, 2 infiltrations épidurales par voie interépineuse sous repérage anatomique à l'aide d'une aiguille spinale de dimension 20Gauge 0,90x88mm. Un corticoïde particulaire est utilisé, à savoir une ampoule de 5 ml d'acétate d'hydrocortisone pour chaque geste infiltratif. À J5 de la sortie d'hospitalisation, la patiente présente des céphalées accompagnées de vertiges se majorant à la position orthostatique. Un scanner cérébral sans injection est effectué. Celui-ci retrouve un hématome sous dural subaigu de localisation fronto-pariétale gauche s'étendant à la tente du cervelet gauche, d'environ 4 mm d'épaisseur (fig. 1 et fig. 2). Il n'est pas retenu d'indication neurochirurgicale devant l'absence de signe de focalisation et la stabilité de l'hématome. La symptomatologie s'améliore après 48h d'hydratation IV et le respect du décubitus strict.

Conclusion

Une surveillance rapprochée est nécessaire dans les suites d'une infiltration épidurale. La présence de céphalées persistantes secondairement à une infiltration épidurale exige un examen neurologique approfondi. Une imagerie cérébrale doit parfois être envisagée afin de ne pas méconnaître une étiologie intracérébrale potentiellement fatale. Nous recommandons un repos strict au lit dans les suites immédiates d'une infiltration épidurale.

Mots clés : Infiltration épidurale ; Radiculalgie ; Corticostéroides ; Hématome sous-dural ;

1. Introduction Les infiltrations épidurales de corticostéroides constituent un traitement classique des lomboradiculalgies résistant aux antalgiques de première intention. La description d'accidents neurologiques graves, notamment par la Food and Drug Adminsistration (FDA) [START_REF] Pountos | Safety of Epidural Corticosteroid Injections[END_REF], ainsi que le peu de recommandations des sociétés savantes [START_REF] Manchikanti | Epidural steroid injections safety recommendations by the Multi-Society Pain Workgroup (MPW): more regulations without evidence or clarification[END_REF], a conduit la Societé Française de Rhumatologie (SFR), par l'intermédiaire des sections rachis et de rhumatologie interventionnelle, à établir un certain nombre de recommandations sur l'usage des infiltrations rachidiennes en 2018 [START_REF] Marty | Préconisations pour la réalisation des infiltrations épidurales rachidiennes de corticostéroïdes élaborées sous l'égide de la section « rachis » reconnue par la Société française de rhumatologie, de la section « imagerie et rhumatologie interventionnelle[END_REF]. La description de ces événements neurologiques indésirables bien que peu répandus remet ainsi en lumière la question de la balance bénéfice-risque des infiltrations épidurales.

Cas clinique

Nous rapportons le cas d'une femme caucasienne, âgée de 55 ans, hospitalisée pour la prise en charge d'une lombosciatique de trajet S1 droite rebelle aux antalgiques de pallier 1 et 2. Ses antécédents étaient marqués par une dyslipidémie et un antécédent d'infarctus du myocarde chez la mère à 60 ans. Elle ne présentait pas d'autres facteurs de risque cardiovasculaire, ni de consommation ethylo-tabagique, et ne prenait pas de traitement médicamenteux au long cours. Elle a bénéficié avant son hospitalisation d'un traitement par anti-inflammatoire non stéroidiens pendant plus de sept jours sans efficacité sur la symptomatologie douloureuse. L'examen clinique d'entrée ne retrouvait pas de déficit sensitivo-moteur. Le reste de l'examen clinique neurologique et cardiovasculaire était sans particularité. Un scanner du rachis lombaire sans injection a été réalisé mettant en évidence une protrusion discale latéro-médiane latéralisée à droite en conflit avec la racine S1 droite. Le bilan biologique réalisé à l'entrée d'hospitalisation était sans anomalies notables : absence de syndrome inflammatoire, pas d'anomalies de la numération formule sanguine, pas de thrombopénie, pas de troubles de l'hémostase. Au cours de l'hospitalisation, il a été réalisé à 48 heures d'intervalle, 2 infiltrations épidurales par voie interépineuse sous repérage anatomique à l'aide d'une aiguille spinale de dimension 20Gauge 0,90x88mm. Un corticoïde particulaire était utilisé, à savoir une ampoule de 5 ml d'acétate d'hydrocortisone pour chaque geste infiltratif. Aucun repos n'a été prescrit au décours immédiat des infiltrations. Devant l'amélioration de la symptomatologie, et l'absence de complications immédiates sur le plan neurologique, la patiente est sortie d'hospitalisation le lendemain de la 2 nde infiltration.

A J5 de la sortie d'hospitalisation, la patiente s'est présentée au service des urgences pour des céphalées accompagnées de vertiges se majorant à la position orthostatique. Elle se plaignait également d'un flou visuel à l'oeil gauche ainsi que d'acouphènes. Ses symptômes étaient apparus 24 à 48H après la réalisation de la dernière infiltration épidurale et demeuraient incoercibles malgré la prise d'anti-inflammatoires non stéroïdiens et la prise de paracétamol. L'examen clinique ne retrouvait pas de signes de focalisation neurologique. Le bilan biologique était sans anomalie, ne retrouvant notamment pas de syndrome inflammatoire ni de trouble de l'hémostase. Un scanner cérébral sans injection a été effectué. Celui-ci retrouvait un hématome sous dural subaigu de localisation fronto-pariétale gauche s'étendant à la tente du cervelet gauche, d'environ 4 mm d'épaisseur (fig. 1 et fig. 2). Pas de syndrome de masse associé.

Un transfert en neurologie a été réalisé avec réalisation d'un blood patch de 23mL, le maintien d'un décubitus strict ainsi que la mise en place d'une hydratation par voie IV. La symptomatologie de la patiente s'est améliorée après 48H de traitement. Il n'a pas été retenu d'indication neurochirurgicale en raison de l'absence de signe de focalisation et de la stabilité de l'hématome. Une imagerie de contrôle a été réalisée à 1 semaine et à 1 mois d'intervalle montrant tout d'abord un aspect stable puis une régression de l'hématome sous dural.

Discussion

La survenue d'événements secondaires neurologiques faisant suite à une infiltration épidurale a été décrite, bien que leur incidence reste difficile à quantifier [START_REF] Pountos | Safety of Epidural Corticosteroid Injections[END_REF] En 2014, la FDA a analysé sa base de données de pharmacovigilance portant sur toutes les injections rachidiennes de corticoïdes [START_REF]FDA Epidural Steroid Injections (ESI) and the risk of serious neurologic adverse reactions Meeting BDAaADPAC[END_REF]. Il a ainsi été rapporté 131 cas d'accidents neurologiques graves (dont 41 cas d'arachnoidites). Une revue de la littérature menée par la section rachis de la SFR en 2018 rapportait 20 cas de complications neurologiques graves (paraplégie, tétraplégie…) répertoriés entre 2002 et 2016 secondaires à une infiltration du rachis lombaire [START_REF] Marty | Préconisations pour la réalisation des infiltrations épidurales rachidiennes de corticostéroïdes élaborées sous l'égide de la section « rachis » reconnue par la Société française de rhumatologie, de la section « imagerie et rhumatologie interventionnelle[END_REF]. La majorité des cas décrits était secondaire à une infiltration par voie foraminale. Seuls 3 cas d'accidents neurologiques graves résultant tous d'une ischémie médullaire ont été décrits au décours d'une infiltration épidurale par voie interépineuse.

L'hématome sous-dural est une complication rarissime de l'infiltration épidurale pouvant potentiellement engager le pronostic vital. Le taux de mortalité de l'hématome sous dural aigu, malgré une nette amélioration ces dernières années reste élevé, avec un taux de mortalité estimé respectivement à 34 % et 39 % dans plusieurs études [START_REF] Atalay | Risk factors associated with mortality and survival of acute subdural hematoma: A retrospective study[END_REF]. À notre connaissance un seul autre cas d'hématome sous dural imputable à une infiltration épidurale du rachis lombaire a été publié ce jour dans la littérature [START_REF] Ozdemir | Acute intracranial subdural hematoma after epidural steroid injection: a case report[END_REF]. Plusieurs cas ont été décrits faisant suite à une anesthésie péridurale réalisée lors de l'accouchement. Ceux-ci restent extrêmement rares avec moins d'une centaine de cas décrits et une incidence estimée à 1/500 000 [START_REF] Szeto | Intracranial subdural hematoma after epidural anesthesia: a case report and review of the literature[END_REF][START_REF] Lim | Subdural Hematoma Associated With Labor Epidural Analgesia: A Case Series[END_REF] La physiopathologie de l'hématome sous dural secondaire à une infiltration épidurale repose sur une hypotension de liquide céphalo-rachidien (LCR) faisant suite à une brèche durale. Cette hypotension entraîne une traction, et un déchirement des veines confluentes en pont dans l'espace sous dural [START_REF] Szeto | Intracranial subdural hematoma after epidural anesthesia: a case report and review of the literature[END_REF]. Les facteurs de risques d'un hématome sous dural apparaissant secondairement à la réalisation d'une infiltration épidurale sont potentiellement : le diamètre de l'aiguille, la grossesse, une coagulopathie, une atrophie cérébrale, la deshydratation, la consommation ethylique [START_REF] Atalay | Risk factors associated with mortality and survival of acute subdural hematoma: A retrospective study[END_REF]. Une intervention neurochirurgicale est généralement indiquée pour les hématomes de plus de 10 mm d'épaisseur ou bien en cas de signe de focalisation neurologique [START_REF] Gerard | Treatment of acute subdural hematoma[END_REF]. Dans notre cas, il n'a pas été relevé de brèche par l'opérateur au cours du geste infiltratif. Il est décrit la notion de céphalées apparaissant 24 à 48h après le geste infiltratif, sans notion de traumatisme présenté par la patiente, ni de coagulopathies ou de prise d'anticoagulants, permettant de retenir un lien de causalité entre le geste infiltratif et la survenue d'un hématome sous dural. La fréquence d'une brèche sous durale est difficile à estimer et non systématiquement rapportée au cours d'une infiltration épidurale. Des études évoquent une fréquence à 3,6 % chez les anesthésistes pratiquant une anesthésie péridurale. [START_REF] Gurudatt | Unintentional dural puncture and postdural puncture headache-can this headache of the patient as well as the anaesthesiologist be prevented?[END_REF]. La description de céphalées persistantes secondairement à une infiltration épidurale amène à la plus grande vigilance et à un examen neurologique approfondi, afin de rechercher des étiologies intracrâniennes, à différencier du syndrome post-ponction lombaire, survenant plus fréquemment. Les signes cliniques qui étaient classiquement décrits dans les cas rapportés d'hématome sous dural secondaire à une brèche durale étaient [START_REF] Szeto | Intracranial subdural hematoma after epidural anesthesia: a case report and review of the literature[END_REF] des céphalées (74-91 %), des nausées/vomissements (31-41 %), des troubles cognitifs (31-40 %), un déficit neurologique (23-28 %), une diplopie/flou visuel (14-20 %), une aphasie/dysarthrie (11-13 %) Dans notre cas l'hématome sous dural s'est manifesté par des céphalées rebelles aux antalgiques, un flou visuel et des acouphènes.

Ceci met en exergue la possible question d'une surveillance rapprochée suite à un geste d'infiltration du rachis lombaire par voie épidurale. Se pose la question d'une hospitalisation systématique en cas de programmation d'un tel geste afin d'optimiser son encadrement, favoriser un repos strict au lit de quelques heures et de détecter les éventuelles complications neurologiques au décours du geste, bien que rares.

Nous décrivons dans ce cas clinique l'apparition d'un hématome sous dural dans les suites d'une infiltration épidurale. Les événements neurologiques secondaires aux infiltrations épidurales restent rarement décrits dans la littérature, la plupart faisant suite à une infiltration par voie foraminale. La présence de céphalées persistantes secondairement à une infiltration ne doit pas faire conclure de manière précipitée à un syndrome post ponction lombaire. Elle doit amener à un examen neurologique approfondi à la recherche de signe de focalisation voire à une imagerie cérébrale afin de ne pas méconnaître une étiologie intracérébrale, notamment un hématome sous dural. Une surveillance rapprochée semble souhaitable dans les suites immédiates d'une infiltration épidurale.

Déclaration de liens d'intérêts

Les auteurs déclarent ne pas avoir de liens d'intérêts.

Fig. 1 .

 1 Fig. 1.Scanner cérébral sans injection mettant en évidence une hyperdensité en croissant en localisation fronto-pariétale gauche, caractéristique d'un hématome sous dural mesuré ici à 4 mm d'épaisseur (flèche).

Fig. 2 .

 2 Fig. 2. L'hématome sous dural s'étend au niveau de la tente du cervelet (flèche).


P Frobert

R Vaucher

G Vaz

F Gouin

P Meeus

E Delay

Place de la chirurgie réparatrice dans la prise en charge des sarcomes des tissus mous des membres The role of Reconstructive Surgery after Soft Tissue Sarcoma Resection

Keywords: Sarcome des membres, conservation de membre, lambeau perforant, séquelles post radiques, lipomodelage Soft-tissue sarcoma, limb-sparing surgery, perforator flap, post-radiation sequalae, fat grafting

Les sarcomes des tissus mous sont des tumeurs malignes rares et de mauvais pronostic. Leur prise en charge doit être multidisciplinaire au sein d'une structure spécialisée du réseau NetSarc. Une chirurgie d'exérèse avec marges microscopiques saines (R0 selon l'UICC) est l'intention de toute prise en charge curative. Lorsqu'ils se développent au sein d'un membre, la chirurgie d'exérèse peut menacer le maintien d'une fonction, voire du membre dans son intégralité. De nos jours, la chirurgie conservatrice du membre associant une exérèse élargie, combinée à la radiothérapie, est la règle dans environ 90% des cas. Une chirurgie réparatrice est nécessaire dans au moins 25% des cas pour préserver le membre, limiter les complications postopératoires mais également dans le cadre de la prise en charge des séquelles. Les progrès de la chirurgie réparatrice, notamment au travers de la microchirurgie, ont permis de repousser les limites de la chirurgie d'exérèse et d'en améliorer les résultats. Toutefois, la priorité doit toujours être donnée aux marges d'exérèse définies par le chirurgien cancérologue, à confronter aux possibilités de reconstruction, sans que celles-ci ne soient un facteur limitant. Une collaboration étroite et forte entre le chirurgien plasticien et le chirurgien cancérologue est donc un élément précieux dans la prise en charge de ces patients. Le chirurgien plasticien se doit de maîtriser l'ensemble de la chirurgie des lambeaux, en tenant compte de l'impact de la radiothérapie pré ou post-opératoire. Les lambeaux perforants ont permis d'augmenter la qualité des reconstructions proposées aux patients tout en diminuant les séquelles du site donneur et constituent une indication de choix dans ces situations. Le lipomodelage, réalisé à distance du traitement et après bilan préthérapeutique, est actuellement la technique la plus efficace dans le traitement des séquelles. Plusieurs séances sont nécessaires pour obtenir une amélioration significative.

Introduction

Soft tissue sarcomas (STS) are a heterogeneous group of tumors developed in extraskeletal conjunctive tissues. Representing around 1% of malignant tumors in adults, they call for multidisciplinary management [START_REF] Blay | Improved survival using specialized multidisciplinary board in sarcoma patients[END_REF][START_REF] Haddad | Évaluation de la prise en charge des sarcomes des tissus mous en Franche-Comté depuis l'instauration d'une réunion de concertation pluridisciplinaire au CHRU. À propos de 47 cas[END_REF]. Approximately 40% of these tumors develop on a limb. They are aggressive tumors, and 5year survival is around 65%, whatever the stage or the localization. Standard treatment for localized STS is wide monobloc excision with safe margins of healthy tissue, preceded or followed in most cases by radiation therapy [START_REF] Hoefkens | Soft tissue sarcoma of the extremities: pending questions on surgery and radiotherapy[END_REF][START_REF] Dadia | Characteristics, diagnosis and treatment of bone and soft tissue sarcomas[END_REF][START_REF] Endo | Surgical margins in the management of extremity soft tissue sarcoma[END_REF][START_REF] Misra | The management of soft tissue sarcoma[END_REF]. The respective roles of chemotherapies, targeted therapies and immunotherapies remain under discussion [START_REF] Blay | Getting up-to-date in the management of soft tissue sarcoma[END_REF][START_REF] Blay | The current reality of soft tissue sarcomas: advances, controversies, areas for improvement, and promising new treatments[END_REF]. Quality of initial management determines prognosis of disease-free survival and overall survival; if it all possible, it should be organized in a structure affiliated with the NetSarc network, which is the nationwide clinical reference with regard to sarcomas [START_REF] Blay | Surgery in reference centers improves survival of sarcoma patients: a nationwide study[END_REF][START_REF] Brennan | Lessons learned from the study of 10,000 patients with soft tissue sarcoma[END_REF][START_REF] Genet | Evaluation of the management and conformity to clinical practice guidelines of soft tissues lesions. Study performed at the competence center of Lorraine area[END_REF]. In at least 25% of cases, loss of soft tissue substance following primary exeresis renders indispensable a form of corrective or restorative surgery: widened exeresis, compartmentbased surgery … or amputation [START_REF] Suresh | The Role of Reconstructive Surgery After Skeletal and Soft Tissue Sarcoma Resection[END_REF][START_REF] Slump | Flap reconstruction does not increase complication rates following surgical resection of extremity soft tissue sarcoma[END_REF][START_REF] Dadras | Predictors of oncologic outcome in patients with and without flap reconstruction after extremity and truncal soft tissue sarcomas[END_REF][START_REF] Elswick | A reconstructive algorithm after thigh soft tissue sarcoma resection including predictors of free flap reconstruction✰[END_REF][START_REF] Siegel | Staged Soft Tissue Reconstruction Following Sarcoma Excision with Anticipated Large Cutaneous Defects: An Oncologically Safe Alternative[END_REF][START_REF] Agrawal | Outcomes Analysis of the Role of Plastic Surgery in Extremity Sarcoma Treatment[END_REF]. Reconstruction procedures consist in skin graft, locoregional flap or free flap techniques. The objective of this article is to present and specify the role of corrective surgery and the plastic surgeon in a setting helping to ensure optimally effective multidisciplinary patient management.

The specificities of surgical treatment of soft tissue sarcoma Preoperative biopsy

Any progressive tumefaction of the limb exceeding 5 cm should be considered in the absence of evidence to the contrary as a sarcoma, and it will necessitate MRI or a biopsy [START_REF] Tuttle | Biopsy techniques for soft tissue and bowel sarcomas: Biopsy Techniques for Sarcomas[END_REF].

The radiological characteristics requiring biopsy in cases of soft tissue tumefaction are [START_REF] Peabody | A comparison of the prognoses for deep and subcutaneous sarcomas of the extremities[END_REF][START_REF] Rydholm | Size, site and clinical incidence of lipoma. Factors in the differential diagnosis of lipoma and sarcoma[END_REF]:

-diameter exceeding 50mm

-sub-aponeurotic location -irregular or lobed contours -irregular and thick intratumoral walls or septa -heterogeneous T1 and T2 sequences -early and prolonged contrast enhancement Biopsy must be carried out by a specialized radiologist in an expert center after consultation with an oncologic surgeon, or by the oncologic surgeon himself in cases involving surgical biopsy.

Puncture opening (radio-guided biopsy) or avenue of approach (surgical biopsy) must be located at the level of the future excision scar so as to facilitate secondary or "redo" intervention.

The objective of preoperative biopsy is to obtain a tissue fragment large enough to enable definitive histological diagnosis with low morbidity, and to avoid negatively affecting subsequent therapeutic strategy.

A simple "sarcoma" diagnosis is generally insufficient; a specific histological STS subtype needs to be specified. Precise details will facilitate decisions on therapeutic strategy, orient considerations of neoadjuvant treatment (preoperative radiation therapy…) and help to determine the surgical timetable most conducive to informed patient consent. From a technical standpoint, most biopsies are simple. That much said, decisions on the biopsy indication, the tumor zone to be biopsied and the avenue of approach can make the difference between success and catastrophe.

A poorly executed biopsy can become an obstacle to precise diagnosis and have a negative impact on survival. In extreme cases of "botched" biopsy, amputation can become the only cancerologically correct operation. With these considerations in mind, all preoperatory biopsy procedures have got to minimize the potential risk of tumor dissemination.

To the greatest possible extent, the biopsy trajectory must follow the safest existing anatomic trajectory and avoid crossing anatomic structures or compartments not involved in the planned optimal excision surgery. Fibrous anatomical planes representing barriers to tumor extension (intermuscular septa, fascia subjacent to tissue mass…) have got in all cases to be scrupulously respected. Ideally, the biopsy entrance point should be considered as part and parcel of planning for future local treatments: surgical avenue of approach, irradiation field. In the past, the above precautions concerning biopsy procedures were not necessarily taken in routine practice, given the fact that many malignant tumors were treated by amputation.

In our time, on the contrary, progress in excision surgery, radiation therapy and restorative surgery permit limb conservation in 90 to 95% of STSs in the extremities. It has become indispensable to adjust and scrupulously apply biopsy protocols in a center with adequate experience.

When a physician or a plastic surgeon not specialized in the field finds himself face to a patient presenting with limb tumefaction suggestive of soft tissue sarcoma, it is preferable to immediately address the patient to a specialized referent structure.

The specificities of STS of the limbs

Generally in the limbs, muscle groups and neuro-vascular and lymphatic structures are longitudinally oriented. As a result, most STS excisions are correspondingly longitudinally oriented, from the upper limb to the lower limb, facilitating identification and dissection of critical anatomical structures by minimizing vasculo-nervous and lymphatic resections, reducing operational morbidity and potentially paving the way to direct cutaneous closure. As regards the limbs, all biopsies must choose the shortest trajectory, and be oriented perpendicularly (radio-guided biopsy) or longitudinally to the limb (surgical biopsy). These measures will integrate the biopsy trajectory in the planned exeresis procedure.

Excision surgery

The quality of primary sarcoma excision surgery is a major prognostic factor for risk of local and distant recurrence (5,9,21).

The theoretical objective of curative surgery for STS of the limbs is to achieve resection with wide, tumor-free, microscopically negative margins (R0, according to UICC classification). When preoperative planning raises the suspicion that R0 resection will be difficult to achieve, neo-adjuvant radiation therapy will be envisioned from the outset as a possible option.

It is usually difficult to estimate the ideal distance from the tumor that should be anticipated in preoperative planning in view of achieving R0 resection. In fact, the distance will vary according to histological subtype and tumor location.

Since the standardized treatment procedures proposed in the 1980s by Enneking (22), who formulated the concept of compartmentalization and surgical margins, the latter have been progressively reduced by associating radiation therapy with the operations themselves. Even though there is no current consensus on the optimal thickness of safe margins, they may be considered as adequate when they are microscopically healthy, and can be measured in millimeters in proximity to a healthy anatomical structure (an aponeurosis, for example).

As of now, limb conservation may be envisioned in more than 90% of extremity STS cases, a percentage mechanically increasing indications for restorative surgery on account of the defects occasioned by widened excision surgery. Complex reconstruction procedures in the framework of limb-sparing protocols are frequently called for and need to be incorporated in surgical strategy [START_REF] Suresh | The Role of Reconstructive Surgery After Skeletal and Soft Tissue Sarcoma Resection[END_REF][START_REF] Dadras | Predictors of oncologic outcome in patients with and without flap reconstruction after extremity and truncal soft tissue sarcomas[END_REF][START_REF] Elswick | A reconstructive algorithm after thigh soft tissue sarcoma resection including predictors of free flap reconstruction✰[END_REF][START_REF] Siegel | Staged Soft Tissue Reconstruction Following Sarcoma Excision with Anticipated Large Cutaneous Defects: An Oncologically Safe Alternative[END_REF][START_REF] Agrawal | Outcomes Analysis of the Role of Plastic Surgery in Extremity Sarcoma Treatment[END_REF]. Ideally, sustained collaboration between the oncologic surgeon and the plastic surgeon will lead to their performing operations as a cohesive team, setting an example of fruitful partnership in cancerology.

The surgical timetable

Prior to determining extent of resection and method of reconstruction, a surgical team will be called upon to take into consideration the histological diagnosis, the anatomical location of the tumor, the speed of tumor growth and the patient's state of health.

It is of paramount importance to determine the objective of surgery before setting a timetable for operation [START_REF] Dadia | Characteristics, diagnosis and treatment of bone and soft tissue sarcomas[END_REF][START_REF] Endo | Surgical margins in the management of extremity soft tissue sarcoma[END_REF][START_REF] Misra | The management of soft tissue sarcoma[END_REF]. More often than not, proposed surgical treatment is aimed at curative resection corresponding to complete excision of the extremity sarcoma; in some cases, however, surgery may be considered as a means of improving a patient's quality of life, or as a key element in a symptomatic approach.

In surgery with curative intent, priority is given to wide exeresis, the minimal objective being the production of healthy microscopic margins (R0 resection).

In palliative situations priority will be given to alleviating the patient's symptoms. It bears mentioning that even in palliative surgery, local control of the pathology remains a major goal, given that a local relapse or uncontrollable local disease progression can be devastating for a terminally ill patient.

In preoperative preparation of surgery with curative intent, extent of resection is based on clinical examination and radiological findings (MRI…). Since STS of the limbs can occur at any location in an arm or a leg, anatomical and surgical considerations of infinitely varied.

It will be necessary to painstakingly review the nature and extent of the healthy tissues to be resected around the tumor in order to achieve microscopically healthy resection. In most STSs, a macroscopic margin of several centimeters of soft tissue (muscle or adipose tissue) around the tumor seems indispensable; that much said, a muscle aponeurosis, a fascia or the periosteum can constitute an anatomical barrier with dimensions large enough to allow less extended resection [START_REF] Malawer | Musculoskeletal Cancer Surgery[END_REF].

When there is close contact of the tumor with a vessel, a nerve or a bone, inclusion of the adventitia, the perineurium or the periosteum can contribute to local control of the disease in the framework of planned R1 surgery and as part of a preoperatively elaborated therapeutic strategy. Conversely, postoperative radiation therapy or other adjuvant treatments will in no way compensate for inadequate or unplanned surgery.

In cases involving radiation therapy or neoadjuvant chemotherapy: When lowered tumor volume appears, the extent of surgical excision may at times be reduced. Conversely, in the event of tumor progression occurring notwithstanding neoadjuvant treatment, limb-sparing efforts may be compromised to the point that amputation becomes unavoidable.

In over 90% of cases, limb-sparing surgery currently represents the heart of surgical treatment of limb STS. This has gradually become possible through the development of diagnosis and imagery techniques and improved reconstruction procedures, as well as increased use of radiation therapy and perioperative medical treatment.

Limb-sparing wide exeresis surgery is preferable insofar as it does not entail loss of oncologic opportunity and is conducive to a low rate of local recurrence, with acceptable morbidity (1,9,10).

That much said, amputation can become necessary once the tumor has invaded a major vasculo-nervous axis or a critical anatomical structure, or in cases where tumor volume is markedly massive, and a significant function would be compromised by muscle sacrifice.

Only after having determined the extent of resection and anticipated the degree of loss of substance and the specificities of the anatomical structures involved (skin, muscle, bone, vessel, nerve…) can the surgical indication and reconstruction technique be individualized and "tailored".

It would be extremely ill-advised to proceed the other way around; extent of resection must not be the object of a compromise and should not in any case be diminished in view of facilitating restorative or corrective surgery.

The role of a plastic surgeon in a surgical team

The role of a plastic surgeon in management of STS of the limb is fundamental [START_REF] Suresh | The Role of Reconstructive Surgery After Skeletal and Soft Tissue Sarcoma Resection[END_REF][START_REF] Slump | Flap reconstruction does not increase complication rates following surgical resection of extremity soft tissue sarcoma[END_REF][START_REF] Dadras | Predictors of oncologic outcome in patients with and without flap reconstruction after extremity and truncal soft tissue sarcomas[END_REF][START_REF] Elswick | A reconstructive algorithm after thigh soft tissue sarcoma resection including predictors of free flap reconstruction✰[END_REF][START_REF] Siegel | Staged Soft Tissue Reconstruction Following Sarcoma Excision with Anticipated Large Cutaneous Defects: An Oncologically Safe Alternative[END_REF][START_REF] Agrawal | Outcomes Analysis of the Role of Plastic Surgery in Extremity Sarcoma Treatment[END_REF].

The plastic surgeon's role is vital not only in preoperative planning and delivery of restorative surgery, but also in postoperative management. For example, his expertise can be called upon when monitoring wound healing, a process that may be adversely affected by unfavorable local conditions following neoadjuvant irradiation the existence of a multioperated area, or the presence of comorbidities such as smoking, diabetes, obesity… In other situations, when there exists a risk of exposure of deep-seated anatomical structures or osteoarticular or prosthetic material, reliable covering must be ensured, using locoregional or free flaps.

Transposition or transfer of healthy and well-vascularized tissues tolerating "multimodal" treatments (radiation therapy, chemotherapy…) can enhance cicatrization and help to reduce postoperative complications.

It is incumbent upon a plastic surgeon to be familiar with all soft tissue reconstruction techniques, and to be highly skilled in microsurgery.

Restorative surgery is aimed not only at covering losses of cutaneous substance, but also at obliterating "void spaces" and at restoring the contours and function of the limb.

To sum up, the role of the plastic surgeon will be to have his specific expertise effectively contribute to the common interest of the patient and the surgical team, the objective being to enhance the chances of wound healing and conservation of limb function. His close acquaintance with angiosomes and perforasomes will be conducive to planning for surgery insofar as it reduces the risks of postoperative cicatricial complications. Effective coordination between the oncologic surgeon and the plastic surgeon will facilitate surgical planning and preparation.

To conclude, it seems primordial to underline our belief that the plastic surgeon should be integrally involved in team functioning as a key actor in multidisciplinary management of limb STS, and not as a "service provider" tasked with intervening as a consultant when a postoperative course is complicated. Organization of the teams participating in STS management must allow patients to be seen preoperatively and simultaneously by the surgeon who will carry out the excision and the surgeon who will carry out the reconstruction.

Peculiarities of limb reconstruction after sarcoma

The impact of radiation therapy

It is necessary for a plastic surgeon not only to possess experience of surgery in irradiated patients, but also that he comprehend the importance of providing reliable reconstruction, with tolerance of radiation therapy, which is usually delivered at highly elevated doses (superior to 50Gy). Neoadjuvant irradiation is likely to increase the risk of disunion or delayed cicatrization, particularly when a wound is closed under tension [START_REF] Hoefkens | Soft tissue sarcoma of the extremities: pending questions on surgery and radiotherapy[END_REF]. In these situations, soft tissue reconstruction can effectively contribute to wound healing.

Following excision for limb STS in irradiated patients, utilization of resistant flaps with strong vascularization is likely to yield speedier wound healing, reduction of revision operations and secondary covering procedures, and shorter hospital stay. To sum up, the flaps will improve the chances of sparing the limb. Flap tolerance of radiation therapy is generally excellent. In our experience, skin grafts show more variable tolerance, and partial if not total necrosis may compel suspension of adjuvant radiation therapy. In addition to yielding uneven results, in an irradiated patient skin grafts have the drawback of being poorly adapted to the functioning of limb flexion areas.

The peculiarities of loss of soft tissue substance

Losses of substance occasioned by excision surgery are often large-scale, pluritissular and liable to expose major vasculo-nervous or osteo-articular anatomic elements.

That is why, more often than not, restorative surgery will consist in flap surgery, especially insofar as flaps tend to tolerate high-dose radiation therapy.

In our experience, restorative surgery can take place either on the same day, concomitantly to excision, or else at a later date. This point should be discussed between the oncologic surgeon and the plastic surgeon, and the final decision will largely depend on the elements exposed following exeresis surgery. The advantage of delayed reconstruction is that it is a two-step procedure, allowing the surgical team the time to ensure healthy resection margins prior to planning for the second surgery, which may be quite complex and would be ill-advised, were the margins to be invaded.

To avoid delaying potential adjuvant treatments, the time elapsed between the two operations should be as short as possible. In fact, programing of the second operation depends on (a) how long it takes for the definitive histological results to be rendered and (b) the scheduling logistics of the operating theater. While waiting, patients' dressings are regularly changed, and the wound healing process is closely monitored. Negative pressure therapy can be applied. When two-step surgery is not possible due to major vascular, osteo-articular or prosthetic exposure, restorative surgery is performed at the same time as the excision.

Elements determining choice of reconstruction

In addition to the clinical examination evaluating the patient's overall condition and past medical history, it is imperatively necessary to estimate the extent of the exeresis and the nature of the relevant healthy resection tissues (skin, muscle, vessels, nerve, bone) and anticipate the type of reconstruction to be planned and the composition of the flap to be harvested.

It is also necessary to be aware of the impact of radiation therapy that the patient may previously have undergone or will possibly be undergoing as adjuvant treatment.

Last but not least, it will be necessary to specify the objective of resurfacing, of filling or, in some cases, of conservation/ functional reanimation.

The role of skin grafts

We have retained as indications for skin graft: superficial losses of substance in nonirradiated territory or territory without adjuvant irradiation and small-sized losses of substance (fewer than 5 cm of major axis). Skin graft will also come into play in situations not conducive to flap use due to the location of the loss of substance or to the overall patient's health status and characteristics (comorbidities, multi-operated, inadequate morphology…).

Skin graft techniques may in some cases be associated with the use of artificial derma. That much said, due to the repercussions of radiation therapy, more often than not restorative surgery will involve a covering flap.

The role of flaps

In reconstructions necessitating skin contribution, the surgical objective must not be limited to cutaneous covering; functional and cosmetic aspects as well as possible sequalae at the donor site have also got to be taken into account.

In this respect, the arrival of perforator flaps has minimized donor site sequelae by putting an end to the removal of muscles or fascia previously used as "vessel-bearing" anatomical structures [START_REF] Sinna | À propos des lambeaux perforants…20 ans après[END_REF][START_REF] Blondeel | The "Gent" Consensus on Perforator Flap Terminology: Preliminary Definitions[END_REF]. Muscle flaps have gradually been supplanted by perforator flaps, of which the technical advantages (including the possibility of fine dissection) are numerous.

In our experience, muscle flaps are usually preferred in cases of extended loss of tissue substance (latissimus dorsi free flap), for surgeries of filling without cutaneous resurfacing (local or free muscle flap), for functional reanimation (neurotized latissimus dorsi flap, neurotized gracilis flap) or, finally, in the event of mistaken indication of perforator flap (possible vascularity or inadequate patient morphology). It bears mentioning that when a "pure" free muscle flap is associated for the purposes of resurfacing with a thin skin graft, a new surgical site, the site of harvesting, will be necessary. Wound healing will take more time, and the patient will manifest less tolerance for radiation therapy. Moreover, the possibility of resurfacing with a thin perforator flap [START_REF] Adani | Hand Reconstruction Using the Thin Anterolateral Thigh Flap[END_REF][START_REF] Chaput | Thinning: The Difference between Free and Propeller Perforator Flaps[END_REF][START_REF] Choi | Thin superficial circumflex iliac artery perforator flap and supermicrosurgery technique for face reconstruction[END_REF][START_REF] Dast | Thin flaps in the management of hand and upper limb defects[END_REF][START_REF] Qassemyar | Thin perforator flaps elevated in the plane of the superficial fascia: Principle and surgical procedure[END_REF] may in some cases allow the surgeon to get around the difficulties associated with supposedly inadequate morphology (obesity…). Last but not least, it is possible to harvest a composite perforator flap including muscle fascia in view of achieving functional tendon repair and reconstruction (anterolateral thigh fascia lata flap) [START_REF] Michel | Dynamic reconstruction of Achilles tendon by free composite perforator flap with functional assessment[END_REF]. For all of these reasons, we tend to prefer perforator flaps, which bring to bear signally "epidermized", high-quality tissues that can be deployed on a large-scale surface, without loss of opportunity for the patient in the event of failure.

Local flaps or free flaps

Given the usual extension of losses of substance, a local perforator propeller flap harvested from a limb can only rarely be "self-closing". It also bears mentioning that the vascular reliability of a local flap on an upper limb may be relatively low when the flap covers a large surface, leading at times to partial flap suffering [START_REF] Vitse | Perforator-based propeller flaps reliability in upper extremity soft tissue reconstruction: a systematic review[END_REF][START_REF] Chaput | Propeller Perforator Flaps of Extremities Seem Less Reliable[END_REF][START_REF] Boucher | Reconstruction of elbow defect by perforator propeller flap of the brachial region--clinical observation[END_REF][START_REF] Bekara | A Systematic Review and Meta-Analysis of Perforator-Pedicled Propeller Flaps in Lower Extremity Defects: Identification of Risk Factors for Complications[END_REF][START_REF] Bekara | Free versus perforatorpedicled propeller flaps in lower extremity reconstruction: What is the safest coverage? A meta-analysis[END_REF][START_REF] Gobel | Perforator propeller flap for cutaneous coverage of the knee[END_REF][START_REF] Qassemyar | The perforator propeller flap[END_REF]. Moreover, when a surgeon opts for a local flap, he is called upon, if at all possible, to select a donor site more distal than the loss of substance to be covered.

In the event of local recurrence, it is currently recognized that the entire cicatricial zone is at risk of tumor contamination. If an amputation is finally indicated, the level of amputation may be largely influenced by the position of scars that may have been engendered by a local flap.

Concretely speaking, production of a local flap harvested proximally to the loss of substance could in the event of local recurrence expose the patient to more proximal amputation than would otherwise be the case. This factor should be taken into account when choosing a local flap, which should be distal with regard to the loss of substance.

In clinical practice, we tend to prefer free perforator flaps insofar as they permit wider coverage with high-quality tissues without loss of opportunity for the patient. Furthermore, a free flap generates few new scars on the surgical site of reconstruction, and has no impact, in the event of local recurrence, on level of amputation.

What flap for which topography?

While the anatomical site to reconstruct will not be the only factor dictating a surgeon's choice of flap, it will figure into his decision, with emphasis being laid on the idea of "like with like" repair.

For example, the characteristics of the tissue to be transported to the hand or the weightbearing surface of the foot will not be the same as those to be transported to the axillary fossa or the thigh.

In this section, we will be proposing some preferred indications according to anatomical site of reconstruction; that much said, a reconstructive surgeon will on all occasions need to exhibit adaptability and creativity in the spirit of "tailored" reconstruction.

Upper limb (Table 1)

Needs for reconstruction of the elbow, the arm, the wrist and the hand are excellent indications for reconstruction by free perforator flap in the STS framework [START_REF] Adani | Hand Reconstruction Using the Thin Anterolateral Thigh Flap[END_REF][START_REF] Dast | Thin flaps in the management of hand and upper limb defects[END_REF]. Reconstruction will require fine tissues, to be deployed on a potentially extended surface. At the level of the arm, the axillary fossa and the shoulder, the tissue to be transported will need not only to be sufficiently thick, but also to cover a larger surface.

Hand, wrist, forearm and elbow

In free flap reconstruction, topographies do not necessarily require a long vascular pedicle. More often than not, arterial anastomoses are termino-lateral.

In our experience, the Superficial Circumflex Iliac Artery Perforator Flap (SCIP flap) (39,40) (Figures 1A and 1B If we only rarely prefer them, it is due to their impact in the event of local recurrence on level of amputation and to their relatively low vascular reliability on extended surfaces.

Arm and axillary fossa

While needs for reconstruction of the arm, the axillary fossa and the shoulder are excellent indications for reconstruction by free perforator flap (Figures 4A et 4B), they can also undergo reconstruction by muscle or musculocutaneous pedicled flap of the total or partial latissimus dorsi (MSLD -muscle-sparing latissimus dorsi flap) [START_REF] Mojallal | Breast reconstruction with Muscle-Sparing Latissimus Dorsi flap combined to a Thoraco-Abdominal advancement flap and fat grafting[END_REF], or in the perforator form of a pedicled TDAP or parascapular flap.

In extreme cases of STS of the shoulder or the axillary fossa in which the impossibility of conserving an upper limb necessitates interscapular-transhumeral amputation, a fillet flap for composite transfers [START_REF] Perrot | Fillet flap for axillary reconstruction[END_REF][START_REF] Kreutz-Rodrigues | Extremity free fillet flap for reconstruction of massive oncologic resection-Surgical technique and outcomes[END_REF] permits excellent reconstruction of the shoulder stump in an exceptional situation.

Lower limb (Table 2)

As is the case with an upper limb, reconstruction of the foot, the ankle, the leg and the knee requires thin flaps and large surfaces. Free perforator flaps are of prime importance. In the thigh and the inguinal fossa, a number of local solutions can be considered, especially in the event of mistaken indication for free flap.

Foot, ankle, leg and knee.

Free perforator flaps including SCIP flap (Figure 5), ALT flap (Figure 6) and TDAP flap offer high-quality covering in virtually every case [START_REF] Bekara | Free versus perforatorpedicled propeller flaps in lower extremity reconstruction: What is the safest coverage? A meta-analysis[END_REF][START_REF] Ali | The Versatility of the Anterolateral Thigh Flap[END_REF][START_REF] Koshima | Superficial Circumflex Iliac Artery Perforator Flap for Reconstruction of Limb Defects[END_REF][START_REF] Ayhan | Thoracodorsal artery perforator flap: a versatile alternative for various soft tissue defects[END_REF].

As regards foot reconstruction, it will matter to choose a flap thin enough to not interfere with footwear. One peculiarity of foot reconstruction consists in a need for reconstruction of the plantar surface, and is by no means easy to bring to the foot a skin surface of quality equivalent to the plantar surface; a risk of local discomfort persists. In some cases, a free internal plantar flap can be considered as an appealing option.

Perforator flaps stemming from the anterior or posterior tibial artery can also arouse interest, provided that they are "self-closing" and distally positioned with regard to the loss of substance.

Particularly as concerns a lower limb, a composite anterolateral thigh flap including a fascia lata strip will ensure sturdy fastening for functional tendon reconstruction (Achilles tendon, knee extensor mechanism) [START_REF] Michel | Dynamic reconstruction of Achilles tendon by free composite perforator flap with functional assessment[END_REF], provide a sliding plane in the presence of subjacent osteoarticular prosthetic material, and enable hermetic closure of an articular capsule of the knee joint.

Thigh and inguinal fossa

Reconstruction of the knee, the popliteal fossa, the thigh and the inguinal fossa can employ not only the same free flaps (SCIP flap, ALT flap, TDAP flap), but also a certain number of pedicled flaps, including anterograde or reverse pedicled ALT, tensor fascia lata musculocutaneous or perforator flap, and pedicled DIEP.

Treatment of sequelae

Types of sequelae

The sequelae STS of the extremities can be esthetic and functional. As regards functional sequelae, what matters most is to limit them during primary treatment; if muscle reanimation is necessary, it should be integrated to the first stage of reparation; at a later stage, radiation damage may render it difficult to perform muscle transfer surgery under proper conditions. As for the esthetic sequelae, they have mainly to do with deformation, lack of volume, scar retraction, enlarged scars and browning of the skin subsequent to radiation therapy.

Therapeutic modalities

As regards therapeutic modalities, prior to modern-day fat transfer, otherwise known as lipofilling [START_REF] Delay | Breast implant alternatives[END_REF], local reconstructions by flap were being attempted, but surgery was arduous and at high risk of complications, and the outcomes were generally poor, to the extent that quite often, it was decided not to treat the morphological and esthetic sequelae. Later on, in the wake of the fat transplant technique initiated by Coleman [START_REF] Coleman | Long-term survival of fat transplants: controlled demonstrations[END_REF], who initially used fat in facial cosmetic surgery (lipostructure), in 1998 we developed a lipomodeling technique [START_REF] Delay | Fat injection to the breast: technique, results, and indications based on 880 procedures over 10 years[END_REF][START_REF] Delay | Lipomodelling of the reconstructed breast[END_REF][START_REF] Delay | The Role of Fat Grafting in Breast Reconstruction[END_REF]. It quickly became quite effective, not only as concerns volume correction, but also in terms of tissue and trophicity improvement and treatment of radiation sequelae. The same observation has been put forward by other authors [START_REF] Coleman | Structural fat grafting: more than a permanent filler[END_REF][START_REF] Rigotti | Clinical treatment of radiotherapy tissue damage by lipoaspirate transplant: a healing process mediated by adipose-derived adult stem cells[END_REF]. We initially applied this technique in breast reconstruction [START_REF] Delay | Fat injection to the breast: technique, results, and indications based on 880 procedures over 10 years[END_REF][START_REF] Delay | Lipomodelling of the reconstructed breast[END_REF][START_REF] Delay | The Role of Fat Grafting in Breast Reconstruction[END_REF][START_REF] Delay | Efficacy of lipomodelling for the management of sequelae of breast cancer conservative treatment[END_REF]. Given how well it worked, we have used it for other sequelae of cancer such as post-radiation sequelae on the face (60), and have noted highly positive effects on the irradiated tissues. Lipomodeling is currently considered as the technique of choice in treatment of the morphological and esthetic sequelae of sarcomas of the extremities. Concerning oncologic safety, no association has been found between risk of local recurrence and lipomodeling aimed at alleviating sequelae of soft tissue sarcoma [START_REF] Pennati | Autologous fat grafting after sarcoma surgery: Evaluation of oncological safety[END_REF]. That much said, some cases raise questions on the stimulatory role of fat in the event of local osteosarcoma recurrence [START_REF] Perrot | Safety concern between autologous fat graft, mesenchymal stem cell and osteosarcoma recurrence[END_REF][START_REF] Avril | Opposite Effects of Soluble Factors Secreted by Adipose Tissue on Proliferating and Quiescent Osteosarcoma Cells[END_REF].

Close and careful examination

Painstaking examination of the treatment area is imperatively necessary as a means of seeking out any sign of local recurrence. Tissue trophicity and the dimensions of radiation sequelae require testing. The color and suppleness of the skin provide good indications. The surface of the irradiated zone will likewise need to be taken into account, particularly in the limbs when the sequel is circumferential. A precise examination will lead to determination of recipient tissues and to evaluation of the number of lipomodeling sessions to be carried out.

The examination will also help to delineate potentially available adipose zones. In the event of limb STS sequelae, it will be necessary to program several sessions and to envision several harvest zones, which will subsequently necessitate optimal management.

Preoperative evaluative imaging

After treatment for soft tissue sarcoma of the extremities, a substantial amount of time (usually 5 years) should be allowed to elapse, whereas an advisable time lapse after the sequelae of conservative breast cancer treatment is two years [START_REF] Delay | Lipomodeling in breast reconstruction[END_REF][START_REF] Delay | Indications and Controversies in Total Breast Reconstruction with Lipomodeling[END_REF]. Once 5 years have gone by, and provided that test results are altogether normal, preoperative imaging is systematically carried out so as to make sure that there is no evolutive lesion. The preferred test is limb soft tissue MRI, which is routinely performed in annual monitoring of sarcoma of the extremities. The MRI must be recent (1 or 2 months before the operation) with regard to the lipomodeling treatment envisioned. As is the case with the breast (64), any doubtful lesion found through MRI must be subjected to a micro-biopsy aimed at eliminating any possibility of local recurrence.

Planning out the sessions

Taking into account the local tissues and the recipient tissues, the number of sessions must be determined. When radiation sequelae on the limbs are circumferential, the results of the initial sessions may seem inconclusive. Indeed, while the first two sessions frequently have a trophic effect, they often appear disappointing in terms of volume effect. That is why it is necessary to explain to patients that when sequelae are sizable, it usually takes 3 or 4 sessions to provide suitable treatment. It is of paramount importance to adequately select the fat removal areas; it would be unfortunate to prematurely choose, as early as the first sessions, a zone from which harvesting is relatively easy; that zone will most likely be more sorely needed during the next-to-last or the final session, when the tissues will have become more trophic, and will more readily accept a larger quantity of fat.

Operative technique

Operative technique was recently and precisely described, accompanied by video films, in an article published in the Annales de Chirurgie Plastique Esthétique (64); it will be briefly evoked in the present study.

Harvesting

The donor sites were preoperatively identified at the level of the steatomeries. Harvesting was carried out with a 10 ml syringe following serum adrenalin infiltration (1 mg of adrenalin in 500cc) using a blunt 5-hole cannula.

Preparation of the fat

The fat is centrifuged for 15 seconds at 3200 rpm, enabling conservation of the fat-like phase and collection in the syringes of 10ml of centrifuged fat.

Transfer

Several punctiform incisions are carried out using a pink 14G trocar. The fat is replanted using the same cannulas as in breast lipomodeling. Since the tissues are relatively fibrous, the first session permits only a limited transfer of adipose tissue. Once the recipient tissues are close to saturation [START_REF] Delay | Lipomodeling in breast reconstruction[END_REF], several fasciotomies are performed in the adhesion areas, and the transfer of 20 to 30 ml of supplementary fat occurs. During the first and second sessions it is necessary to proceed cautiously so as to avoid zones cytosteatonecrosis, of which the proximity would compromise the following sessions.

Peculiarities according to location

At the level of an upper limb, the required quantity of fat varies according to the proximal or distal nature of the sequelae. In the distal areas, the quantities utilized during each session are often relatively low, and it takes 3 or 4 sessions programmed at 3-to-4-month intervals to significantly heal the lesions. On the other hand, the scapular region (Figure 7) consumes a sizable quantity of adipose tissue, which means that larger amounts have got to be transferred during each of the usually 3 or 4 programmed sessions.

At the level of a lower limb, the gluteal region consumes considerable volume, and it behooves the surgeon to closely control the quantity of available fat, of which the first sessions permit only limited transfers; it is only after achievement of improved trophicity that it becomes advisable to transfer a more substantial quantity of fat. At the level of a lower limb, irradiation will in many cases have generated a circumferential fibrous sequel (Figure 8), and once again, it will be necessary to proceed progressively, with 3 or 4 sessions programmed at 3-to-4-month intervals in function of the healing of local tissues. In some cases, it will be advisable to allow more time between sessions for the trophic and regenerative effectiveness of the fat to appear. At the level of the lower limbs, fasciotomies strongly contribute to expansion of the fibrous zones; needless to add, the subjacent nervous and vascular elements must be taken into consideration.

Results

The outcomes of treatment for the sequelae of soft tissue sarcoma of the extremities have been highly encouraging. Fat has a volumizing morphological effect that facilitates correction of subcutaneous folds and enhances symmetry between the two limbs. In a lower limb, it is often useful to reduce the contralateral side by means of liposuction and fat harvesting, thereby improving the symmetry effect. In addition to morphological amelioration, we have noted improved skin trophicity and patient comfort, as well as diminution in certain cases of pain and dysesthesias. Moreover, trophic amelioration permits attenuation of oft-present radio-dystrophy and in all likelihood contributes over time to limitation of the risk of radiation necrosis, which may be appreciable due to initial high-dose irradiation in STS treatment. It also matters to know that when, 3 or 4 years later, patients wish for further improvement, lipomodeling can be reiterated. In a majority of cases, the results have been good or very good; in our series, all patients have considered themselves satisfied or very satisfied. After lipomodeling, neither local evolution nor complication has occurred.

Conclusion

Over recent years, surgery for soft tissue sarcoma of the extremities has become highly codified.

In this context, in association with preoperative and postoperative radiation therapy, plastic surgery can effectively contribute to conservation of a functional arm or leg in the framework of limb-sparing surgery.

Restorative or reconstructive surgery can be of importance not only subsequent to primary exeresis, but also at a later stage in treatment of the sequelae of surgery or radiation therapy. Anatomically diversified and technically challenging, restorative surgery calls upon the whole gamut of reconstruction techniques, from the simplest to the most complex. The arrival of perforator flaps, many of which are free rather than pedicled, has favored proposals for high-quality solutions in practically all cases of limb STS.

Close collaboration between the oncologic surgeon and the plastic surgeon is of paramount importance. Each patient represents a "peculiar case" to be treated in accordance with rigorous overall principles of which the scrupulous application renders indispensable the functioning of an experienced surgical team. Collaboration between surgeons provides the patient with optimal multidisciplinary management concerning soft tissue sarcoma of the extremities.

Treatment of sequelae is of major import from not only a morphological and esthetic standpoint, but also as regards psychological recovery. Lipomodeling is the most effective currently applied treatment for the above-mentioned sequelae and should be proposed only once a sufficient amount of time has elapsed following the previous treatments and only after complete preoperational testing including MRI has been carried out. The relevant information should be transmitted to cancerologists in view of ensuring systematic and synergistic care and treatment for these patients.

  ), the Anterolateral Thigh Perforator Flaps (ALT flap or thin ALT flap) (41) (Figures 2A and 2B) with or without aponeurosis, the Thoracodorsal Artery Perforator Flap (TDAP flap) (42-44) (Figure 3A et 3B) and the Deep Inferior Epigastric Artery Perforator Flap (thin DIEP flap) (45) are quality options in practically all cases. Aside from free perforator flaps and local perforator propeller flaps, local fascio-cutaneous flaps such as the radial forearm flap and the posterior interosseous flap or the pedicled perforator propeller flaps stemming from the radial or ulnar artery are plausible alternatives.

Table 2 .

 2 Some preferential indications for reconstruction in lower extremity STS in the framework of limb-sparing surgery ALT flap, SCIP flap, serratus anterior muscle flap, internal plantar flap Local: pedicled perforator flap, internal plantar flap Free: SCIP flap, ALT flap, TDAP flap, serratus anterior muscle flap, latissimus dorsi flap, gracilis flap, fibula flap Local: pedicled perforator flap, sural neurocutaneous flap Free: SCIP flap, ALT flap, TDAP flap, serratus anterior muscle flap, latissimus dorsi flap, fibula flap Local: pedicled perforator flap, sural neurocutaneous flap Free: ALT flap, SCIP flap, TDAP flap, serratus anterior muscle flap, latissimus dorsa flap Local: pedicled perforator flap, gastrocnemius flap Free: ALT flap, SCIP flap, TDAP flap, serratus anterior muscle flap, latissimus dorsi flap Local: pedicled perforator flap, reverse-ALT flap, gastrocnemius flap Free: latissimus muscle flap, ALT flap, DIEP flap Local: Pedicled ALT flap, pedicled perforator flap, pedicled DIEP flap Free: ALT flap, muscle or musculocutaneous latissimus dorsi flap Local: Pedicled ALT flap, pedicled DIEP flap, perforator or musculocutaneous TFL flap, pedicled perforator flap

Figure 1A .

 1A Figure 1A. Soft tissue sarcoma of the thenar eminence of the left hand. Harvesting of a left-side SCIP flap.

Figure 1B .

 1B Figure 1B. Donor site of left-sided SCIP flap (left). Postoperative result a month and a half after surgery (right) Figure 2A. Soft tissue sarcoma of the right forearm. Reconstruction by left-sided anterolateral thigh perforator flap. .

Figure 2B .Figure 3B .Figure 4A .

 2B3B4A Figure 2B. Postoperative result one year after surgery (above and below at the left). Donor site (below on the right) Figure 3A. Sarcoma of the left forearm. Reconstruction by right-sided thoracodorsal perforator flap (above). Postoperative view a month and a half after surgery on initiation of adjuvant radiation therapy (below) Figure 3B. Postoperative view one year after surgery at the donor site (below on the right) Figure 4A. Angiosarcoma of the right axillary fossa. Exeresis exposes the axillary vessels, the brachial plexus and the rib cage.

Figure 4B .Figure 5 .

 4B5 Figure 4B. Reconstruction of the axillary fossa by right-sided anterolateral thigh perforator flap. Perioperative view (above) and result at 1 month (below) Figure 5. Soft tissue sarcoma of the right leg. Reconstruction by right-sided SCIP flap.

Figure 6 .

 6 Figure 6. Soft tissue sarcoma of the right leg. Reconstruction by thin left-sided anterolateral thigh flap.

Figure 7 .

 7 Figure 7. Sequel sarcoma of the left axillary fossa treated by 4 sessions of lipomodeling.

Figure 8 .

 8 Figure 8. Sequel of sarcoma of the left thigh treated by 4 sessions of lipomodeling.

Figure 1A .

 1A Figure 1A. Sarcome des tissus mou de l'éminence thénar de la main gauche. Prélèvement d'un SCIP flap gauche.

Figure 1B .

 1B Figure 1B. Site donneur du SCIP flap gauche. (Gauche) Résultat post opératoire à 1 mois et demi. (Droite)

Figure 2B .

 2B Figure 2B. Résultat post opératoire à 1 an. (Haut et bas à gauche) Site donneur. (Bas à droite)

Figure 3B .

 3B Figure 3B. Vue post opératoire à 1 an et du site donneur. (En bas à droite)

Figure 5 .

 5 Figure 5. Sarcome des tissus mou de la jambe droite. Reconstruction par SCIP flap droit.

Figure 6 .

 6 Figure 6. Sarcome des tissus mous de la jambe droite. Reconstruction par lambeau antérolatéral fin de cuisse gauche.

Figure 7 .

 7 Figure 7. Séquelle de sarcome du creux axillaire gauche traité par 4 sessions de lipomodelage.

Figure 8 .

 8 Figure 8. Séquelle de sarcome de la cuisse gauche traitée par 4 séances de lipomodelage.

Declarations of ties of interest

The authors have no ties of interest to declare.

Anatomical region Flap option

Hand