MM occupies 1% of cancer cases, as well as about 10% of hematologic cancer cases.[10]MM shows a relatively higher morbidity in male than in female, and its morbidity is two-fold in the blacks as high as that in the whites.[11, 12]MM will affect the old population, and 70% cases are diagnosed when they are 60 years old.[13]MM stands for a kind of plasma cell dyscrasia that is featured by immortalized monoclonal plasma cell growth within bone marrow. Nearly each MM case progresses from the asymptomatic monoclonal gammopathy of undetermined significance (MGUS) at the pre-malignant stage.[14, 15] Moreover, MGUS will further develop into MM or associated cancers at an annually growing rate of 1%.[16, 17]
Bone lesions induced by MM are indicative of MM, and they will reduce the patient life quality. About 80% cases develop osteolytic bone disorders when they are diagnosed, besides, they are linked with a higher risk of skeletal-related events (SREs) that will increase the morbidity as well as mortality.[18]About 60% MM cases have fractures in the course of disease.[19]The uncoupled bone-remodeling process lays the pathogenic foundation of bone disorders associated with myeloma. The myeloma cell-bone microenvironment interaction will eventually activate osteoclasts while suppressing osteoblasts, giving rise to bone loss. Multiple intercellular as well as intracellular signal transduction pathways participate in the complicated course of MM. The crosstalk mediated by myeloma across diverse molecular pathways forms a forward feedback to maintain survival of myeloma cells as well as keep the decomposition of bone, even after reaching the disease plateau.[20]
MM is diagnosed when at least one myeloma defining event (MDE) and at least 10% clonal plasma cells are detected through bone marrow examinations or when plasmacytoma is detected in a biopsy. MDEs are constituted by the recognized CRAB (hyperCalcaemia, Renal failure, Anaemia, Bony lesions) characteristics and 3 representative biomarkers, including over one focal lesion detected through MRI, ≥ 60% plasma cells in clonal bone marrow, as well as ≥ 100 serum free light chain (FLC).[21] In the case of suspicious MM in clinic, M protein testing is recommended by combining serum immunofixation (SIFE), serum protein electrophoresis (SPEP), as well as serum FLC assay.[22] About 2% MM cases develop the real non-secretory disorder with no M protein tested in the above-mentioned tests.[23] Positron emission tomography/computed tomographic (PET/CT) and low-dose whole body computed tomography (WB-CT) scans are the best ways to assess the bone disorder severity,[22, 24]which can show the changes of bones and the soft tissues more clearly, and display the boundaries of the lesion. Plain radiographs are usually non-specific which even underestimate the extent of the lesion, and they are performed only when no other advanced imaging can be accessed. MRI is a particularly useful imaging technique of choice due to its noninvasive nature and greater anatomic detail, particularly when smoldering multiple myeloma (SMM) is suspected, so as to eliminate the risk of focal lesion in the bone marrow observed prior to the occurrence of the actual osteolytic disorder. MRI also greatly contributes to the assessment of suspicious cord compression and extramedullary disorder, and when it is necessary to visualize a certain symptomatic region.
MM accounts for a disorder with progressive relapse. The MM cases may possibly recur with clinical symptoms or with biochemical disorders. Holistic and multidisciplinary treatment is needed for each MM case.[13] Treatment qualification involves multiple factors, which needs the collaboration from radiotherapists, orthopedic surgeons, radiologists, hematologists and anesthesiologists. In this regard, it is necessary to construct a prognostic model to predict disease stage, evaluate patient general conditions, and detect the underlying chronic disorders or the possible adjuvant treatments.[2] For optimizing the outcomes for individuals, elucidating the most suitable maintenance treatment or continuous therapy for specific patient group is important; besides, it is important to consider the clinical safety, effectiveness, tolerability, life quality, convenience, feasibility, together with long-time treatment burden on the patients.[21]
In addition to oncological and antineoplastic systemic therapy, surgical therapy in patients with MM represents an essential treatment pillar within the framework of supportive therapy measures and is the task of orthopedic tumor surgery. For SREs related to myeloma, surgery is mainly performed for the sake of maintaining and restoring the involved skeletal function and recovery, reducing patient sufferings like (pain) and improving patient mobility as well as life quality.[25, 26]There is a need for surgical intervention not only for the care and treatment of stability-threatening bone lesions and manifest pathological fractures, but also for the treatment of tumor-related complications, such as neurological deficits, paraplegic clinical pictures or in the case of conservative therapy-refractory bone pain. The surgical methods and time of treatment should be decided individually depending on the risk and prognostic outcomes for myeloma cases.[25]Osteolyses of non-supporting skeletal sections such as the ribs, skull or scapula usually do not require surgical treatment. The physical status grade established by the American Society of Anesthesiologist (ASA) has been extensively utilized to evaluate the patient general conditions or anesthesia tolerance. Patients with < 2 months survival or ASA = 4 will be treated using conservative methods instead of surgery.[27]
Surgery is usually conducted to treat the MM-induced proximal humeral fracture, so as to relief patient suffering and recover the involved bone function and mobility, as well as patient life quality. However, surgical strategies are complicated and demanding.[28]
Endoprosthetic reconstruction has been extensively used to treat proximal humeral fracture, but it can not achieve satisfactory effect on the impaired function. Prosthesis can be a good way to relieve pain and fix the fracture, but it has poor functional recovery than other treatments.[6, 29–31] Besides, more tendons and muscles are sacrificed during resection, which inevitably impair the function.[30] At the same time, plate fixation is associated with numerous drawbacks, like short protection length, massive soft tissue stripping, and risk of nerve injury.[8, 32, 33] Beside, local relapse may give rise to fixation loss or the need of a second operation.[29, 34]As a result, plates are restricted in treating metastasis.
IM nailing is suggested to be unsuitable to treat proximal humeral fracture because of the bone defect and thin cortex following curettage.[29]Therefore, at present, IM nailing is restricted to treating diaphyseal fractures.[5]Our results reveal that IM nailing can serve as an efficient and robust way to treat proximal humeral fracture. Generally speaking, applying IM nailing to fix proximal humeral fracture is advantageous in its decreased operation time, small lesion, decreased soft tissue dissection, as well as early recovery.
In this case, we applied the technique in treating proximal humeral fracture, particularly when no bone cement is used to augment the lesion. Finally, at our follow-up visits, our case had markedly relieved pain and improved shoulder function. At the 40-month follow-up, the patient had favorably healed humeral fracture, complete lesion healing was observed, and no pain was reported by the patient. In comparison with contralateral shoulder, the forward flexion and abduction were limited at the terminal 10°, meanwhile, complete external and internal adduction and rotations were achieved.
Despite it is generally incurable, the long-time survival of MM is greatly improved because more treatments are developed recently. Besides, the improved survival is also associated with the application of early treatment.[35] As suggested by randomized controlled trials (RCTs) that apply modern treatments, MM has the median survival of about 6 years. The appropriate treatment for metastases is needed to prolong patient survival.[36]
Although this technique has achieved satisfactory effect, there are few reports that describe it for the treatment of pathological fractures of the proximal humerus caused by MM. Therefore, it is necessary to conduct a large sample of studies to further validate the efficacy and to identify the surgical indications and related complications.
The patient was satisfied with the current functional recovery and the treatment of primary disease, and agreed to report his case, hoping to benefit more patients suffering from the same disease.
To conclude, when pathological fracture of the proximal humerus caused by multiple myeloma occurs, early surgical treatment is indicated, which could relieve pain effectively and allow early movements. IM nailing can be applied to this kind of fractures, without removal of tumors, bone cement augmentation for bone defect or local adjuvant therapy was employed. Moreover, patients can receive combined therapy and have a good prognosis.