Reconstruction of Humeral Shaft Defect with an Intercalary Endoprosthesis Following Resection of Tumor

Abstract

Diaphyseal defects in long bones of extremities following segmental resection are very common in the clinic, and reconstruction remains a great challenge. Although there are many treatments for diaphyseal defects at present, reconstruction with an intercalary endoprosthesis may be an optimal method. We demonstrate a surgical technique for reconstruction of a humeral shaft defect with an intercalary endoprosthesis following tumor resection, and achieve a good clinical outcome. We conclude that in comparison with other methods, reconstruction with an intercalary endoprosthesis is simple, effective, and allows for earlier weight bearing and more rapid restoration of function.

Introduction

Diaphyseal defects in long bones of extremities, mostly caused by trauma, severe infection, and tumor resection, are very common in the clinic. Instead of arthroplasty or amputation, diaphyseal reconstruction following segmental resection has become an increasingly popular approach with the development of imaging and treatment through surgery. There are numerous benefits for patients, including preservation of joint and bone mass. However, determining how to reconstruct the diaphyseal defects remains a challenge, even though there are many treatment options, such as bone grafting (autologous or allogeneic), Ilizarov technology (distraction osteogenesis), Masquelet technology (membrane‐induced osteogenesis), and prosthesis implantation.

Bone grafting is most frequently used in the clinic, with encouraging successful outcomes in diaphyseal reconstruction1, 2, 3. However, simultaneous complications, such as nonunion, refracture, and infection4, 5, 6, are also common, especially for tumor patients, who are at greater risk of complications because of radiation and immunosuppressive chemotherapy7, 8. Although Ilizarov technology is satisfactory for the treatment of the diaphyseal defects in limbs9, 10, 11, 12, restrictions in specific operation devices and complicated surgical procedures may be significant drawbacks. Following Ilizarov technology surgery, most patients endure persistent pain caused by the external fixator and are non‐weight bearing for a long period of time. Meanwhile, complications are often reported, including pseudoarthrosis formation, axial deviation, joint contractures or stiffness, pin tract infection, and skin or bone rupture13, 14. Masquelet technology has been applied in the clinic for more than a decade. The operation is simple and effective, with fewer complications15, 16, 17. However, this technique requires at least two stages of surgery, and it is not suitable for patients with a short life expectancy or who are in palliative care. Diaphyseal reconstruction with prostheses brings advantages, including early weight bearing, early rehabilitation, and low rates of infection18, 19, 20, but reports on this technique are few in number. In the clinic, diaphyseal lesions are often repaired by joint replacement instead of diaphyseal reconstruction, because there is no suitable prosthesis, and the adjacent joint has to be removed. The preservation of the joint is critical to the functioning of the affected limb, especially for younger patients or older patients with a longer life expectancy.

The purpose of this study is to demonstrate the surgical technique for reconstruction of a humeral shaft defect with an intercalary endoprosthesis following tumor resection. In this paper, we present a typical case of a 77‐year‐old female patient who was admitted to our department with multiple myeloma (MM), and suffered from a pathological fracture in the upper segment of the right humeral shaft in July 2017. We reconstructed the affected humerus following the lesion resection with an intercalary endoprosthesis to illustrate the clinical efficacy and feasibility of the intercalary endoprosthesis.

Case Presentation

Patients

A 77‐year‐old female patient complained of pain, swelling, and limited activity in the right shoulder for 2 months. There had been no obvious cause of pain in the right shoulder 2 months previously. The pain worsened and swelling occurred in the right shoulder 1 month prior to presentation. X‐rays, CT, and MRI were examined after admission. Preoperative routine blood tests showed that white blood cell count, erythrocyte sedimentation rate, and C‐reactive protein were increased, and that hepatorenal function were normal.

Imaging Study

A PET‐CT scan before admission showed multiple low‐density bone destruction accompanied by increased metabolism, which was in accordance with the imaging of malignant tumors. After admission, an X‐ray film revealed a fracture with medial angulation deformity of the fragments in the upper shaft of the right humerus. The lesion extended 4.0‐cm proximally and distally from the fracture site and appeared as osteolytic destruction without surrounding reactive sclerosis osteolytic (Fig. 1A, B). A CT scan displayed osteolysis with “moth‐eaten” destruction of cortical bone in the humerus adjacent to the fracture (Fig. 1C). MRI to assess the extent of the intramedullary tumor showed that the lesion was approximately 5.0 cm in length based on signal transformation of bone marrow on T1WI images; the border of the tumor was blurred and the surrounding soft tissue was swollen (Fig. 1D).

Figure 1.

A fracture with medial angulation deformity of the fragments in the upper shaft of the right humerus, and the lesion with osteolytic destruction without surrounding reactive sclerosis osteolytic. (A, B) Preoperative anteroposterior and lateral radiographs. (C) CT showing osteolysis with “moth‐eaten” destruction of cortical bone in the humerus adjacent to the fracture. (D) MRI showing the signal transformation in bone marrow, the indistinct border of tumor, and swelling of the surrounding soft tissues. (E, F) Postoperative anteroposterior and lateral radiographs showing the excellent location of endoprosthesis and no sign of loosening. (G) Intercalary endoprosthesis with lap joint design showing. (H–J) Intraoperative photograph showing the procedure of endoprosthesis implantation: (H) parallel osteotomies for en bloc resection of the tumor, (I) intercalary endoprosthesis implantation with cement (J) plate fixation.

Prostheses

An intercalary endoprosthesis (WEGO, Weihai, Shandong) with a lap joint design was used in the operation (Fig. 1G). To customize the endoprosthesis, the manufacturer used the details based on preoperative imaging regarding the size of the intramedullary space and the lesion, and the estimated size of resection. The titanium intercalary endoprosthesis consists of two components, which are connected with a lap joint and fixed by two screws. The other ends of these components with a fluted intramedullary stem are cemented into the corresponding humeral canal.

Surgical Technique

After induction of general anesthesia, the patient was placed in a dorsal position with somatosensory‐evoked potential monitoring. A 15.0‐cm anterior longitudinal humeral incision was made on the right upper arm, 5.0 cm above and below the lesion of the bone. We incised the skin in line with the anterior border of the deltoid muscle from a point midway between its origin and insertion, distally to the level of its insertion, and then proceeded in line with the lateral border of the biceps muscle to within 7.5 cm of the elbow joint. We divided the superficial and deep fasciae and ligated the cephalic vein. In the proximal part of the wound, we retracted the deltoid laterally and the biceps medially to expose the shaft of the humerus. Distal to the insertion of the deltoid, we exposed the brachialis muscle, split it longitudinally to the bone, and retracted it subperiosteally: the lateral half to the lateral side and the medial half to the medial; thus, the lesion was totally exposed. The radial nerve as it winds about the humeral shaft was exposed and protected carefully. If desired, the distal end of this approach may be carried to within 5.0 cm of the humeral condyles and the proximal end farther proximally, as in the anteromedial approach to the shoulder.

The resection planes for osteotomies, as identified on preoperative imaging, were accurately imprinted. An oscillating saw was then used to make parallel cuts for en bloc resection with wide margins, and the segment of involved bone was removed from the humeral shaft. Small vessels were cauterized using an electrocautery and the surgical wounds were irrigated with sterile isotonic saline. Reaming, in turn, to accommodate the prosthesis was performed. Each fragment of the bone was reamed to a depth 1.0‐cm longer than stem length, and a diameter at least 0.2‐cm larger than stem size to allow for adequate cement mantle around the stem. After reaming, the implant was trialed to verify that the endoprosthesis was seated appropriately within the canal and the lap joint was secured with screw fixation. The surgical site was then irrigated while polymethylmethacrylate cement was mixed. After cement was injected into the proximal and distal intramedullary canal, the two stems were simultaneously cemented into the proximal and distal medullary canals, and held in place to make sure the length and alignment of the arm remained accurate until the cement hardened. The lap joints were assembled and reduced, and locked by two screws. A torque‐limiting screwdriver was then used to lock the two screws fully. The humerus and endoprosthesis were fixed by a plate with unicortical screw fixation (Video S1). Following the last irrigation, soft tissues covered the implant, and wounds were closed in layers with one drainage tube left in place. The resected specimen was sent for histological examination (Fig. 1H–J).

Postoperative Management

Intravenous antibiotics were administered for 3 days postoperatively. The drainage tube was removed when the output was minimized to less than 50 mL during a 24‐h period (2 days postoperatively). The patient was encouraged to attempt full range of motion without restrictions regarding weight bearing as pain permitted and was followed up clinically and radiologically (Fig. 1E,F). The wound dressing was changed every 3 days until the wound healed, and stitches were taken out 2 weeks later. The pathological examination of the specimen revealed myeloma.

Discussion

Pathologic lesions of the humerus due to metastatic disease, myeloma, and lymphoma often represent a significant orthopaedical treatment challenge. When the lesions lead to pathologic fracture, operative treatment is deemed necessary. Joint‐sparing segmental resection of diaphyseal tumors becomes more appropriate, especially for older patients with longer life expectancy, because it avoids a series of complications caused by joint resection21. There are many ways to repair segmental defects following tumor resection, as described in numerous studies. However, at present, reconstruction with an intercalary prosthesis may be the optimal method for repairing diaphyseal defects following tumor resection. The operation is simple, effective, and time saving, and is suitable for patients who are able to tolerate the surgery regardless of their life expectancy or age. The endoprosthesis with cement provides early stability and pain relief. With earlier weight bearing and quicker rehabilitation, it helps improve patients’ quality of life, not only for those in palliative care and for patients with shorter life expectancy, but also for the patients with longer life expectancy. A low incidence of early complications is another significant advantage of cement prothesis. There is some concern about nonunion and infection. However, this treatment is an effective option combined with postoperative radiotherapy and chemotherapy.

However, the following should be considered when using an intercalary endoprosthesis. First, the tumor should be resected completely. En bloc excision of the tumor should be carried out completely to obtain a safe surgical margin. This is key to reducing recurrence rates of tumors. Second, attention must be paid to the rotation of the arm. When the intercalary endoprosthesis is implanted into the humeral medullary cavity, the orientation and rotation must be carefully adjusted. When the affected humeral shaft is already fractured, nothing can serve as a reference and rotational alignment must be corrected by visual inspection by keeping the arm in a neutral position. Third, the location of the tumor must be noted. The length and diameter of the intercalary endoprosthesis stem should be customized according to the location of the lesion based on preoperational images. When the lesion involves the midshaft, the isthmus will be removed, and the diameters of the proximal and distal parts of the humerus will be similar to each other. However, when the lesion is located proximal or distal to the isthmus, there is a large discrepancy between the diameters of the proximal and distal medullary cavity of the humerus. It is, therefore, crucial to consider the location of the tumor base in determining the parameters of the endoprosthesis when the endoprosthesis is customized.

Conclusion

Reconstruction with an intercalary endoprosthesis following diaphyseal resection of the humerus is a good option for tumor patients. In comparison with other limb‐salvage options, such as bone grafting, Ilizarov technology, and Masquelet technology, reconstruction with an intercalary endoprosthesis is simple, effective, and the clinical outcome is much better.

Supporting information

Videos S1 Reconstruction of Humeral Shaft Defect with an Intercalary Endoprosthesis.