[Complication management following resection and reconstruction of the upper limbs and shoulder girdle]. / Komplikationsmanagement nach Tumorresektion und Defektrekonstruktion an der oberen Extremität und am Schultergürtel.

BACKGROUND: Sarcomas of the upper limbs commonly affect the proximal humerus or scapula. Complications after tumor resection and reconstruction are rare but cannot be neglected, particularly after tumor endoprosthetic reconstructions. MATERIALS AND METHODS: The most common complications after resection of sarcomas of the upper limbs and shoulder girdle are described, and current knowledge regarding complication management is presented. Additionally, a selective literature search was performed, incorporating personal experiences. RESULTS: Wound healing disorders and infections after tumor resection without specific reconstruction (clavicle resection, scapulectomy) usually respond well to conservative or surgical treatment. However, periprosthetic infections after reconstruction using a megaendoprosthesis constitute a severe and frequent complication, with an incidence of 5-10%. Two-stage implant replacement still represents the gold standard, although in selected cases, one-stage revision with retention of the prosthetic stem appears warranted. Secondary amputation as a result of periprosthetic infection is rare compared to the situation with infections of the lower limb. Mechanical complications necessitating surgical revision are mostly limited to joint dislocation after inverse total shoulder replacement (TSR). (Sub)luxation in anatomic TSR can be tolerated provided there is no tendency toward perforation of the skin in a asymptomatic patient. Biological reconstructions are most often indicated for reconstruction of intercalary defects of the humerus, and revision is necessitated most frequently by mechanical complications. Despite multiple surgical revisions, stable reconstructions and limb salvage can usually be achieved in the upper limb.

[Treatment concepts for complications after resection and defect reconstruction of pelvic tumours]. / Behandlungskonzepte von Komplikationen nach Resektion und Defektrekonstruktion pelviner Tumoren.

BACKGROUND: Partial pelvic resection, internal hemipelvectomy or sacrectomy as a result of bone sarcoma is still challenging. No matter what kind of reconstruction is used, there is still a much higher rate of complications in pelvic surgery compared to sarcoma surgery of the long bones. OBJECTIVES: We describe the most common complications in pelvic sarcoma surgery and specific complications related to the reconstruction method. Handling strategies for these complications are specified. METHODS: We performed a literature search and report our own experiences in the troubleshooting of pelvic surgery-related complications to gain an up-to-date overview of the state-of-the-art in management strategies. RESULTS: Prospective randomized trials or meta-analyses on this topic are lacking. The literature search depicted that, besides local recurrence, deep infection after reconstruction is the most serious complication. An early revision with radical debridement has to be performed in order to save the reconstruction. In the case of a deep infection, the removal of all implants with a total loss of the reconstruction is often unavoidable. Therefore, an individualized risk-benefit analysis prior to surgery with respect to the type of reconstruction, or no reconstruction at all (hip transposition), together with the patient is advisable. CONCLUSIONS: Complications-especially infections-after hemipelvectomy or sacrectomy are common. In the case of infection, in some cases, an early revision is the only chance to prevent a reconstruction from explantation.

[Hemipelvectomy for pelvic sarcomas]. / Hemipelvektomie bei Sarkomen des Beckens.

BACKGROUND: Hemipelvectomy is an important technique for the treatment of pelvic sarcomas. OBJECTIVES: Presentation of the technical overview, as well as surgical and oncological outcomes of sarcoma patients treated with pelvic tumor resections and treatment recommendations. METHODS: Retrospective analysis of 160 patients treated by pelvic tumor resection for chondrosarcoma between 1977 and 2014. RESULTS: Chondrosarcoma was the most common diagnosis leading to pelvic tumor resection in this collective (38%). The mean patient age at operation was 49 years. 44 patients were treated for G1, 83 patients for G2 and 33 patients for G3 or dedifferentiated chondrosarcoma. The mean tumor diameter was ≥10 cm in 76.1% of cases. Limb salvaging operations were possible in 82.5% of patients. The most common reconstruction technique was hip transposition (38.7%). Clear resection margins were achieved in 86.9% (R0). Local recurrence was observed in 22.5%. Distant pulmonal metastasis was diagnosed in 25% of patients. Grading-specific survival was 81.8% for G1, 59% for G2 and 24.2% for G3 or dedifferentiated chondrosarcoma with a mean survival of 84.4, 89 and 69.4 months respectively. CONCLUSIONS: Pelvic tumor resection with clear margins is the most important known positive predictive local factor affecting overall outcomes, in addition to uncontrollable factors such as grading and tumor size. Defect reconstruction depends on multiple factors such as patient age and adjuvant therapy. The stage of the disease has the greatest impact on overall survival rates and should be considered when contemplating pelvic tumor resections in sarcoma patients.

[Current results of tumour endoprosthetics in adolescents and adults]. / Aktuelle Ergebnisse der Tumorendoprothetik bei Jugendlichen und Erwachsenen.

BACKGROUND: The majority of osteoarticular defects after tumor resection in adolescent and adult patients are reconstructed using megaendoprosthetic implants. However, even infant and pre-teen children undergo reconstruction of defects using so-called growing prostheses with an increasing frequency. OBJECTIVES: Presentation of current techniques, outcomes and the most common complications of megaendoprosthetic reconstruction following tumour resection. METHODS: Selective literature review and discussion of current concepts and knowledge in megaendoprosthetic reconstruction against personal experience and treatment strategies. RESULTS: Megaendoprosthetic reconstructions achieve good functional results and long-term limb salvage (ca. 90% of cases) in adolescent and adult patients. Still, periprosthetic infection and mechanical failure of joint components are among the most common complications observed. In infant and pre-teen children treated by reconstruction using a growing prosthesis, mandatory maintenance operations-in the process of elongating the implant-must also be considered when assessing complication risks. CONCLUSIONS: Megaendoprosthetic reconstructions of osteoarticular defects are a standard procedure in adolescent and adult patients. Despite a substantial complication rate, limb salvage is achieved in a majority of patients. When using growing prostheses in younger children, one needs to be aware of additional servicing procedures that occur independently of those arising from complications.

[Endoprostheses for stump formation after hip disarticulation]. / Endoprothesen zur Stumpfbildung nach Hüftexartikulation.

BACKGROUND: Hip disarticulation is a psychologically and physically demanding procedure. However, it remains a therapeutical option whenever limb salvage proves impossible due to sarcoma, severe implant-associated infections or trauma. The stump lengthening procedure (SLP) is a surgical technique that allows partial salvage of the thigh through endoprosthetic proximal femur replacement after hip disarticulation, depending on the amount of viable soft tissue coverage. This leads to a more appealing visual appearance, facilitates prosthetic fitting and significantly improves limb function. OBJECTIVES: Description of indications for SLP, surgical technique, presentation of clinical and functional outcomes. METHODS: Review of applying literature and presentation of outcomes of our own SLP collective. RESULTS: The risk of local recurrence does not increase after SLP compared to hip disarticulation. While the majority of patients can be fitted with an exoprosthesis, a walking aid is usually necessary for ambulation. Exoprostheses are usually worn throughout the entire day, and patients manage distances of a mean of 2000 metres, even if reconstruction lengths are less than 10 cm. Patients aged 50 years or older tend to wear their exoprosthesis for shorter periods of daywear and achieve significantly poorer functional scores. Postoperative complications are common at a rate of 52%. Periprosthetic infection (21%) and soft tissue perforation of the implant with subsequent implant-associated infection (14%) were the most severe complications observed. CONCLUSIONS: The stump lengthening procedure poses a feasible alternative to classic hip disarticulation in patients with multiple prior operations and/or advanced stages of disease. It leads to satisfactory cosmetic and functional results without jeopardizing local tumor control. Stump perforation presents as the most common complication. Apart from improving the ability to sit down comfortably, both patients treated with a curative and palliative intent manage to ambulate using exoprostheses. With increasing age at the time of operation, walking aids are necessary for ambulation.

Ultra-short stem anchorage in the proximal tibial epiphysis after intercalary tumor resections: analysis of reconstruction survival in four patients at a mean follow-up of 56 months.

INTRODUCTION: Tumors localized in the proximal tibial meta-diaphysis often lead to osteoarticular resections. MATERIALS AND METHODS: In this study, we retrospectively reviewed four patients who underwent intercalary tumor resection and reconstruction using an ultra-short stem in the proximal tibial epiphysis, a procedure that to our knowledge has not been reported in literature so far. RESULTS: At the time of operation, the mean patient age was 26.2 years. Three patients were male and one was female. Patients were diagnosed with osteosarcoma in two cases, Ewing's sarcoma and malignant fibrous histiocytoma of bone in one case each. In all cases, wide tumor resections were achieved (osteotomy 3-3.5 cm below the tibia plateau joint surface, mean resection length of tibial bone 18 cm) at a mean time of operation of 198.8 min. Two superficial wound-healing disorders occurred, leading to one surgical revision in each case. One local tumor recurrence occurred 12 months after operation in a patient who discontinued his adjuvant chemotherapy. This patient died of disease, 31 months after operation. Three patients are alive with no evidence of disease at a mean follow-up of 56 months. Walking is not impaired and light sports activities have been reported in all cases. The mean MSTS score is 28/30. CONCLUSIONS: Therefore, we report this reconstruction technique to be considered for special indications where the functional outcome can be improved by preservation of the knee joint in tumors of the proximal meta-diaphyseal tibial region.

[Osteosarcoma and chondrosarcoma of the pelvis and lower extremities]. / Osteo- und Chondrosarkome des Beckens und der unteren Extremitäten.

A wide tumor resection is essential in the therapy of primary malignant bone tumors to minimize the risk of local recurrence and ensure long-term survival. While chondrosarcoma is mainly treated surgically, osteosarcoma therapy consists of both chemotherapy and surgical resection of the tumor. While endoprosthetic replacement after hemipelvectomy tends to be associated with high infection rates and has been superseded by hip transposition and composite osteosynthetic replacements, the use of megaendoprosthetic tumor prostheses is the most common reconstruction technique when the extremities are affected. Biological reconstruction or ablative procedures are reserved for special indications. Overall, the reconstruction techniques presented in this article manage to ensure limb salvage in most patients. Functional outcome, however, greatly depends on the tumor size and site as well as postoperative residual soft tissue coverage.

[Interdisciplinary diagnostic and treatment of bone sarcomas of the extremities and trunk]. / Die interdisziplinäre Diagnostik und Therapie von Knochensarkomen der Extremitäten und des Rumpfes.

Contrary to the relatively common benign bone tumours and tumour-like lesions, bone sarcomas are rare malignancies with an incidence of 0.8 new cases per 100 000 persons per year. The most common primary malignant bone tumour is osteosarcoma, followed by chondrosarcoma and Ewing sarcoma. Osteosarcomas and Ewing sarcomas occur predominantly in children, adolescents and young adults, while chondrosarcomas primarily affect older patients. Most of the tumours are located in the extremities and the pelvis and in about 90% of the cases the surgical treatment can be performed by means of a limb-sparing wide resection. An endoprosthetic or biological reconstruction of the resulting defect, depending on several patient- und tumour-related factors, is usually necessary. Apart from the surgical treatment, patients with osteosarcoma and Ewing sarcoma require a pre- and postoperative chemotherapy, while Ewing sarcoma patients often undergo radiation therapy as well. Regular follow-up examinations are required after the completion of treatment for the early detection and management of local and/or systemic recurrences as well as treatment-related complications. An extensive experience in the clinical and imaging features as well as the interdisciplinary treatment of these tumours is necessary for optimal patient care. Without it mistakes are often made, which can have grave consequences on the patients' prognosis and functional outcome. The centralised treatment of these patients in specialised sarcoma centres is therefore recommended.

[New surgical treatment options for bone tumors]. / Neue Operationsverfahren bei Knochentumoren.

Primary bone neoplasms can be classified into benign, locally/aggressive and rarely metastasizing and malignant tumors. Patients with benign tumors usually undergo surgical treatment in cases of local symptoms, mainly consisting of pain or functional deficits due to compression of important anatomical structures, such as nerves or blood vessels. Locally/aggressive and rarely metastasizing tumors exhibit an infiltrative growth pattern, so that surgical treatment is necessary to prevent further destruction of bone leading to local instability. Finally, the surgical treatment of malignant tumors is, with few exceptions, considered to be a prerequisite for long-term survival, either alone or in combination with systemic chemotherapy. Whereas the main objective of surgery in the treatment of benign tumors is relief of local symptoms with a minimum amount of damage to healthy tissue and minimizing the risk of local recurrence while ensuring bone stability in locally aggressive and rarely metastasizing tumors, the primary goal in the operative treatment of bone sarcomas is the resection of the tumor with clear surgical margins followed by defect reconstruction and the preservation of function. This review examines the current developments in the surgical treatment of primary bone neoplasms with respect to the management of the tumors and novel reconstructive options.

[Benign cartilage tumors. What should I do with incidental findings?]. / Benigne Knorpeltumoren. Was mache ich mit dem Zufallsbefund?

BACKGROUND: The majority of benign bone tumors are cartilage tumors. Most common are enchondroma and osteochondroma. Often they represent incidental findings in radiological diagnostics. Thus, the incidence of cartilage tumors is unknown, as most of them are never diagnosed due to the absence of any symptoms. OBJECTIVES: This article describes the diagnostic and therapeutic approach of benign cartilage tumors, focusing on incidental findings. METHODS: The current knowledge and our own experience in the diagnostics and treatment of benign condroid tumors are presented. RESULTS: As enchondroma represent most often the classic incidental finding without any symptoms or clinical findings, osteochondroma are often diagnosed in young patients by clinical examination showing a painless swelling that can increase in size according to skeletal growth. Most of these asymptomatic enchondroma and osteochondroma are so called "leave me alone lesions" and do not need any treatment, while other benign tumors (e.g., atypical cartilage tumors, chondroblastoma, chondromyxoidfibroma or osteochondroma with a cartilage cap of over 2 cm) need surgical treatment. These active or local aggressive tumors must be differentiated from the "leave me alone lesions". Additionally, patients with syndromes like Ollier disease (enchondromatosis), Maffucci syndrome or hereditary multiple exostosis must be examined and checked carefully as malignant degradation is possible. CONCLUSION: As most cartilage tumors are benign and remain benign, inappropriate diagnostics or operative treatment just to provide security is obsolete. Plain X-ray is often enough for follow-up and other modalities only become necessary when symptoms occur.

[Bone defect reconstruction in bone sarcoma surgery: tumour endoprosthesis versus biological reconstruction]. / Rekonstruktion knöcherner Defekte in der Knochensarkomchirurgie: Tumorendoprothese vs. biologische Rekonstruktion.

BACKGROUND: Primary bone sarcomas typically arise in the long bones and the pelvis of children and adolescence but may also occur in adults. Meta/diaphysial tumour involvement resulting in the necessity of a joint replacement is more common than diaphysial tumour sites. AIM: In the treatment of these tumours, both endoprosthetic replacement and biological reconstruction techniques are used. Each technique has method-specific advantages and disadvantages. RESULTS: To choose the appropriate surgical method, a multitude of influencing parameters need to be considered. The age at treatment (soft tissue situation/estimated growth/biological potential of the bone), therapeutic concept (palliative vs. curative), the tumour site (upper/lower extremity), tumour expansion (diaphysis/metaphysis) and oncological treatment concept (chemotherapy/radiotherapy) are key factors significantly influencing the surgical technique in terms of functional outcome and longevity of the reconstruction. CONCLUSION: Surgical treatment of bone sarcoma requires broad-based experience of the oncological surgeon. Knowledge of the different surgical technics and reconstruction methods is decisive to offer the individual patient the best oncological and functional outcome.

[Management of complications in megaprostheses]. / Komplikationsmanagement bei Megaprothesen.

BACKGROUND: Megaprostheses are frequently used after segmental resection of bone sarcomas, bone metastases, and in large osseous defects in revision arthroplasty. OBJECTIVES: The incidence of the most common complications associated the use of megaprostheses are reported. The management of complications including therapeutic recommendations are described. MATERIALS AND METHODS: The current knowledge and our own experience of complication management with the use of megaprostheses are presented. RESULTS: Prospective, randomized studies or meta-analyses on this topic are lacking. An analysis of the literature shows that beside the occurrence of a local recurrence, periprosthetic infection remains the most serious complication. Two-stage revision remains the gold standard, but a single-stage exchange of the prosthesis without removing the stems might be possible in selected cases. Infection is associated with a higher risk of secondary amputation. In contrast, mechanical failures (e.g., wear of the bushings in knee replacements and aseptic loosening of the stems) can be treated more easily. Dislocation of a proximal femur replacement can mostly be prevented by using bi- or tripolar cups. CONCLUSIONS: Complications with the use of megaprostheses can be successfully treated by revision surgery in most cases.

[Attachment tube for soft tissue reconstruction after implantation of a mega-endoprosthesis]. / Der Anbindungsschlauch zur Weichteilrekonstruktion nach Megaprothesenimplantation.

OBJECTIVE: To restore function and an active range of motion, and stabilize the joint after joint resection. INDICATIONS: Restoration of a joint capsule following reconstruction of a defect using a proximal humerus and femur prosthesis. Reattachment of tendons and muscles. CONTRAINDICATIONS: Acute or chronic infection. Status after cured infection. SURGICAL TECHNIQUE: The attachment tube (Implantcast, Buxtehude, Germany) is attached to the joint capsule (proximal humerus and femur replacement) or directly to the prosthesis (for proximal tibial replacements) using nonresorbable Ethibond® sutures (Johnson & Johnson Medical, Norderstedt, Germany). Bone anchors are used, if the joint capsule has been completely resected. The body of the prosthesis, which has previously been attached to the shaft, is then pulled distally through the tube, and a (bipolar) head or humerus cap is placed on top of it. In the proximal humerus and femur replacement, proximal slitting of the tube may be helpful to reposition the prosthesis under vision. Following repositioning, fixation of the tube is completed ventrally and the slits previously made in the tube are sutured. Fixation of the tube to the prosthesis is carried out either with Ethibond® sutures placed around the tube, or--for a proximal humerus and tibia replacement--it is possible to attach suture material to the prosthesis through eyelets. POSTOPERATIVE MANAGEMENT: Further treatment basically depends on the location of the mega-endoprosthesis used. RESULTS: Macroscopically and microscopically, fibroblasts migrate into the tube's mesh, so that attachment of the soft tissue takes place. As of yet, no cases of luxation have occurred when the tube is used in combination with a bipolar head, and with fixed-implant cups the risk of luxation can be reduced using tripolar cup systems. In patients with a proximal tibial replacement, active straightening of the knee joint can be restored in most cases, although some limitation on active extension is still possible depending on the extent of the tumor resection.

Modelling of non-linear pharmacokinetics in sheep after short-term infusion of cardiotoxic doses of imipramine.

Imipramine was administered to sheep (n = 10) by intravenous infusion in high doses (450 mg-900 mg) to elicit cardiovascular shock. A cardiac assist device was then employed to manage the acute overdose situation. The concentration-time course of imipramine and its metabolite desmethylimipramine in plasma was measured by HPLC. As an indicator of imipramine's cardiotoxic effect, cardiac output was monitored. The aim of the study was to evaluate the pharmacokinetics under these conditions and to assess the efficiency of a cardiac assist device with (n = 5) and without (n = 5) an integrated haemoperfusion unit in removing drug from the circulation. The kinetics of imipramine could be described by a three compartment body model with concentration-dependent clearance resulting in non-linear kinetics. The changes in cardiac output with time could be linked to the pharmacokinetic model by a linear relationship. The cardiac assist device was found to contribute to the overall elimination of imipramine whereas the haemoperfusion unit had no clinically relevant impact.