**4. Percutaneous internal fixation and PMMA bone cement injection for long bone metastasis**

#### **4.1. Femoral neck metastasis**

The femur neck is very vulnerable area to fractures due to senile osteoporosis and metastatic bone cancer [6]. The conservative treatment of metastatic tumors in the femoral neck is difficult because of the frequency of intractable pain and impending or established pathological fracture. Any of the aforementioned methods of treatment may be considered but do not significantly contribute to the stability of the femoral neck. Usually, the patients are treated by either joint replacement or internal fixation for pain palliation. The bipolar hip arthroplasty is a mainstay for femur neck metastasis but is too much a burden to the advanced terminal cancer patient. Recently, a new novel surgical technique for the treatment of femoral neck metastasis using hollow-perforated screws (HPSs) and bone cement was introduced [5–7].

### *4.1.1. Hollow-perforated screw*

The quantitative PET-CT values, SUVmax, and SUVmean showed significant uptake decrease after PMMA injection procedure, which means less glucose uptake and reflects tumor suppression. However, most control lesions were aggravated in the same individual patient.

Previous studies report that after bone cement injection, tumor volume is reduced and histology showed tumor necrosis, which support our hypothesis. Bone scan (BS) is known for good detectability, therapy response monitoring, and long-term follow-up of bone metastases. BS is advantageous for whole skeletal metastases detection [4]. BS and F-18-FDG PET-CT have complementary value as BS can detect osteoblastic metastasis well, and both are good imaging

Interpatient study was unable to be performed due to the differences in patient status (primary tumor, treatment, etc). So we performed comparison study of PS lesion and control lesion in the same patient. In our study, as shown in **Figure 6**, BS showed improved or stable state after PMMA injection procedure, which means local tumor suppression. However, most control

**Figure 6.** PET-CT evaluation after combined percutaneous cement injection surgery showed effective tumor suppres‐

**4. Percutaneous internal fixation and PMMA bone cement injection for**

The femur neck is very vulnerable area to fractures due to senile osteoporosis and metastatic bone cancer [6]. The conservative treatment of metastatic tumors in the femoral neck is difficult because of the frequency of intractable pain and impending or established pathological fracture. Any of the aforementioned methods of treatment may be considered but do not significantly contribute to the stability of the femoral neck. Usually, the patients are treated by

sion in the metastatic bone tumor. Before (above) and after (below) operation.

modality to detect bone metastasis.

134 Tumor Metastasis

lesions showed aggravated state [5].

**long bone metastasis**

**4.1. Femoral neck metastasis**

The hollow-perforated screw (HPS), as illustrated in **Figure 7**, is a newly developed device, modified from a 6.5-mm cannulated screw (Multihole Injection Screw; SOLCO, Seoul, Korea). The screw allows to achieve greater fixation capable of injecting material into the weak bone area simultaneously through its multiple side holes.

**Figure 7.** The hollow-perforated screws have multiple holes for injection. The equipment facilitates percutaneous fixa‐ tion and simultaneous bone cement injection for femur neck.

#### *4.1.2. Surgical technique*

The procedure is performed in the lateral decubitus position under spinal anesthesia. The femoral neck anteversion is drawn with the guidance of C-arm fluoroscopy. Two or three 2.2 mm guide pins are inserted to the femoral neck as the same pattern of cannulated screw fixation in the femoral neck fracture. The length of the inserted guide pin is measured and a small skin incision is made for cannulated drilling. After the cannulated drilling, two or three multihole injection screws are introduced over the guide pins. After checking the location of all screws fluoroscopically, the osteoplasty needles are inserted into the canal of screw. These osteoplasty needles are driven into the silicone tube before insertion, which is made temporarily by segmentally cutting a hemovac line for preventing leakage of injected materials at the con‐ necting site with the screw. The guide pin is removed and low-viscosity PMMA bone cement

**Figure 8.** A 58-year-old female has impending fracture of right femoral neck metastasis by lung cancer. Percutaneous fixation and PMMA bone cement injection are effective methods for prevention of pathologic fracture.

is injected through 1 ml syringes. **Figure 8** shows preoperative and postoperative photographs by percutaneous fixation and PMMA bone cement injection and **Figure 9** shows detailed surgical procedures.

**Figure 9.** Detailed surgical procedure demonstrated for femoral neck metastasis.

#### **4.2. Percutaneous flexible nail fixation and bone cement injection for humerus**

The rigid conventional intramedullary nailing method has been widely used for treatment of traumatic fracture as well as long bone metastasis. When surgeons place rigid nail to the humeral lesion, general anesthesia, locked screws, and sometimes curettage and cementing are required. The current study reported the palliative surgical treatment of metastatic humeral lesions using percutaneous Ender nailing along with bone cement augmentation under regional anesthesia in patients with high-risk advanced cancer [4].

#### *4.2.1. Surgical technique*

After interscalene or axillary regional anesthesia, the patient is placed in the supine position so that fluoroscopy cannot be disturbed. The entry points of the Ender nails (4.5-mm diameters; Smith & Nephew plc, London, UK) are the greater tubercle of the humeral head for proximal and diaphyseal lesions, and the lateral condyle for supracondylar lesions. Ender nails that are long enough to pass the intramedullary metastatic lesion are selected. When the Ender nail is completely seated, the tip at the entry point should be buried beneath the cortex to prevent soft tissue irritation. The osteoplasty needles are directly inserted into the medullary cavity by hand-push or hammering in a percutaneous and transcortical manner. Over two needles are commonly used for decompression of intramedullary pressure during bone cement injection and coverage of larger or skipped lesions. The entry point of the needle is selected at the most easily accessible area to the lesion, which is apart from the neurovascular bundles. After identifying the location of the needles by fluoroscopy, low viscous bone cement is injected through one needle and sequential through other needles.

### **4.3. Percutaneous flexible nail fixation and bone cement injection for femur and tibia**

is injected through 1 ml syringes. **Figure 8** shows preoperative and postoperative photographs by percutaneous fixation and PMMA bone cement injection and **Figure 9** shows detailed

**Figure 9.** Detailed surgical procedure demonstrated for femoral neck metastasis.

regional anesthesia in patients with high-risk advanced cancer [4].

through one needle and sequential through other needles.

**4.2. Percutaneous flexible nail fixation and bone cement injection for humerus**

The rigid conventional intramedullary nailing method has been widely used for treatment of traumatic fracture as well as long bone metastasis. When surgeons place rigid nail to the humeral lesion, general anesthesia, locked screws, and sometimes curettage and cementing are required. The current study reported the palliative surgical treatment of metastatic humeral lesions using percutaneous Ender nailing along with bone cement augmentation under

After interscalene or axillary regional anesthesia, the patient is placed in the supine position so that fluoroscopy cannot be disturbed. The entry points of the Ender nails (4.5-mm diameters; Smith & Nephew plc, London, UK) are the greater tubercle of the humeral head for proximal and diaphyseal lesions, and the lateral condyle for supracondylar lesions. Ender nails that are long enough to pass the intramedullary metastatic lesion are selected. When the Ender nail is completely seated, the tip at the entry point should be buried beneath the cortex to prevent soft tissue irritation. The osteoplasty needles are directly inserted into the medullary cavity by hand-push or hammering in a percutaneous and transcortical manner. Over two needles are commonly used for decompression of intramedullary pressure during bone cement injection and coverage of larger or skipped lesions. The entry point of the needle is selected at the most easily accessible area to the lesion, which is apart from the neurovascular bundles. After identifying the location of the needles by fluoroscopy, low viscous bone cement is injected

surgical procedures.

136 Tumor Metastasis

*4.2.1. Surgical technique*

The small diameter of intramedullary flexible nail fixation provides the space for percutaneous bone cement injection. The combinational percutaneous surgery with flexible nail insertion and bone cement injection can be useful to long bone metastasis patients who cannot undergo conventional intramedullary nailing due to poor life expectancy and multiple surgical demanding fracture risk areas. Although the pathologic fracture can be progressed more by weak stability of flexible nail than by rigid conventional nail, in the selective patient condition, this surgical method is effective to maintain bedside care and reduce further osteolytic progression. Patients with subtrochanteric lesion, pathologic fractures, or joint destructive lesions are excluded.

**Figure 10.** The four areas (left pelvis, both femurs, and left tibia) can be treated at once.

The Ender nail fixation in the humerus, femur, and tibia has some limitation for the bone cement injection. Each osteoplasty needle has to penetrate skin and bone cortex for placing to the intramedullary perimetal area [8]. **Figure 10** shows percutaneous flexible nail fixation and bone cement injection.

**Figure 11.** The multihole injection nail was developed for simultaneous bone cement injection in the course of nail in‐ sertion without adding cortical punctures.

Very recently, the multihole injection nail (SOLCO, Seoul, Korea) has developed into a hollow titanium flexible nail with the tip of multiple side holes. The bone cement could be injected deeply in the course of a percutaneous fixation without adding bone cortex holes. The advantages of this new implant include immediate achievement of stable fixation and effective pain relief, deeper injection of drugs or bone cements, a short recovery time, and high emotional satisfaction from simple operation [9]. The use of the multihole injection nail is shown in **Figure 11**.
