Femur Replacement Due To Bone Cancer

e may be related to long-term. So, now I had a bone scan done yesterday on my femur. Benign (non-cancerous) tumors in the bones are more common than bone cancers. Common diagnoses that stem from abnormal bone scan results include: osteoporosis, bone fractures, bone cancer, bone infection, arthritis, Paget's disease (a bone disorder involving thickening and softening of bones) and avascular necrosis (death of bone due to lack of blood supply. A complete evaluation must be done by Illinois Bone and Joint rheumatologists and spine specialists to determine the diagnosis, extent of the disease, and best approach to treatment. 1 knee patient had 1-stage revision surgery with replacement of a Mega C distal femur tumor prosthesis due to deep infection 1. As you well know, diagnosis of cancer, or even a suspicion of cancer causes a great deal of fear. In healthy individuals, breaks and fractures to the femoral bone are typically the result of blunt force trauma , most commonly from the forceful impact sustained during a serious car accident. Motor vehicle accidents, sports-related injuries, gunshot injuries, and falls are common sources of trauma that can lead to a femur fracture. The 30 plus synovectomies and a Yttrium injection had destroyed too much bone to be viable for a TKR. The femur (thighbone) is the most likely long bone to be affected by metastatic bone disease. Or, you can choose another section to learn more about a specific question you have. Some natural remedies for bone cancer include Yoga,Aloe vera, Green tea and many more. Food and Drug Administration in 1991. Abnormalities of renal size, position, and structural integrity are identifiable on whole-body bone scans, and comments on the status of the kidneys and bladder have become a constant feature in bone scan reports. I was diagnosed 3/06 with breast cancer. Today we have a choice of cementless hip implants, an. 001) at week 96. What is a total hip replacement? A total hip replacement is an operation that removes the arthritic ball of the upper thigh bone (femur) as well as damaged cartilage from the hip socket. Treatment for secondary bone cancer. The femur is the long bone most commonly afflicted with metastatic carcinoma. There is an invisible chemical ebb and flow, a true harmonic. I had a knee replacement and everything was diagnosed after I did not recover as expected. Abnormalities of renal size, position, and structural integrity are identifiable on whole-body bone scans, and comments on the status of the kidneys and bladder have become a constant feature in bone scan reports. It is the most common type of cancer that arises in bones, and it is usually found at the end of long bones, often around the knee. Prophylactic treatment of bone lesions can result in shorter hospital stay and reduced blood loss during surgery, leading to lower mortality 5. Most often affecting the epiphysis of the long bones, the necrotic changes result in the collapse and the destruction of the bone structure. Bone is the most common site for breast cancer metastases, occurring in up to 70% of those with metastatic disease. 3 • Case Study 4 / Artificial Total Hip Replacement success, beginning in the late 1950s. Some patients have experienced a significant reaction to the device and need revision surgery for a secondary hip replacement. Osteosarcoma is the most common malignant (cancerous) bone tumor among children, adolescents and young adults, but it is still a rare disorder. I have been on my walker since mid-may, 2009, because of this pain. Net's Guide to Bone Cancer. Most primary bone tumors in dogs are malignant, in that they usually cause death as a result of local infiltration (e. Secondary bone cancer is also called metastatic bone disease. Occasionally, segmental replacement prostheses, which not only replace the joint surface and nearby bone but also replace varying lengths of diaphyseal bone with metal, can be used. Bone loss that occurs with cancer therapy is generally more rapid and severe than postmenopausal bone loss in women or normal age-related osteoporosis in men. The poster had not yet had the surgery and only posted a couple of times. Avascular Necrosis of the Femoral Head (AVN-FH) refers to a progressive weakening of the knobby head of the thigh bone (femur), resulting in eventual collapse of the bone structure if not remedied in time. 859 is grouped in the following Diagnostic Related Group(s) (MS-DRG V35. Bone cancer is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). The endoprosthesis completely replaces the section of bone affected by cancer and bridges the gap between the top and bottom of the dog’s leg to allow near normal use of the limb. bone, pelvic, or scapular metastatic lesions, of which 117 (54%) involved the femur (Table l), confirming the high frequency of surgically significant femoral metastatic lesions. A fracture happens as a result of trauma following the high force impact, stress or pathological fracture following a trivial injury as a result of certain medical conditions (osteoporosis, bone tumour or osteogenesis imperfect) that weaken the bones. The patient had long-term antibiotic treatment and the prosthesis was never removed. The main portions of femur bone are , Fig. The bone/s affected with cancer have a typical “moth eaten” or “sun burst” appearance; The cortical bone- the white outer part is the strongest part of the bone (looks like a straight line in the normal bone). Bone replacement therapy is a well-established science. lung or breast; cancer affecting bone of hip likely to affect other bones e. There were 61 males and 49 females who ranged in age from 10 to 80 years. Bone metastases most often arise in the hip, femur (thigh bone), shoulder, and spine. The cancer patient with metastases has a shortened remaining life span. Secondary or metastatic bone cancer may be properly referred to as a carcinoma based upon where it first arose. Surgery to clean and flush out the infected bone (debridement). Total knee replacement (TKR) is performed in patients with severe loss of knee cartilage due to injury or inflammation, wear and tear due to various types of arthritis or other aging-related changes in the knee. Cawley MPT. In particular, most of the problems related to the bone cancer tend to result from involvement in the pelvis or spine. The entire femur, plus the hip joint and knee joint, were replaced with artificial components. The most common reason is arthritis, but it can also be done in situations where the patient has fallen and seriously broken the hip. Stiffness is the most common complaint following primary total knee replacement, affecting approximately 6 to 7% of patients undergoing surgery. For that reason, modular or custom-made prostheses are being increasingly used. com Joseph A. The distal (lower) portion of the femur (thighbone) is replaced about every four months. Shop Femur Mouse Pads from CafePress. Across a wide variety of tumors with bone involvement, the frequency of SREs can be reduced through use of osteoclast inhibitors such as bisphosphonates or denosumab. However, others that completely break the bone, cause the bone to be crushed or displaced need immediate surgery. Potential causes of bone cancer The causes of canine osteosarcoma are unknown. In December, 2009, I began with left femur pain and left knee pain on walking. Achieving and maintaining good health is a balancing act. Primary bone cancer is rare, making up around 0. Because of the excellent long-term results with. In the 1950s, Michael Bonfiglio, MD, of the University of Iowa, found a 1. Knee pain has multiple causes, the most common being osteoarthritis, particularly in the older population. Surgery to clean and flush out the infected bone (debridement). Dog bone cancer, also called Osteosarcoma, occurs in about 5% of all tumors in dogs. Osteophyte is the medical term that is associated with this problem, which is actually extra bony growth located over the bone structure. The doctor was also surprised as I was 31 years old and much older than his teenage patients whom this cancer usually affects. Procedures to kill cancer cells with heat or cold may help. Femoral neck is the region connecting the shaft of the thigh bone (femur) to its rounded head, which fits into the hip joint (Picture 1). Failure can be due to infection involving the joint, substantial bone loss in the structures supporting the prosthesis, fracture, aseptic loosening of the components and wear of the prosthetic components. Most people are familiar with these drugs as osteoporosis treatments for postmenopausal women. Earlier this year I started experiencing thigh pain on my left hip that is almost identical to the pain I had before the total hip replacement. Bone metastasis can cause pain and broken bones. In general, low impact activities are recommended because the strengthen the muscles and bone around the hip replacement and allow patients to lead healthier lives. Descriptive statistics was performed using frequencies and percentages. The X-Ray showed a large tumor in my right distal femur. Stiffness is the most common complaint following primary total knee replacement, affecting approximately 6 to 7% of patients undergoing surgery. Bone is constantly undergoing the replacement of old bone with new bone in a metabolic process called remodeling. In order to effectively manage these patients, it is essential to have consistent, reproducible and validated methods of assessing response to therapy. Prolonged overuse can cause a stress fracture known as a femoral stress fracture. Their use will reduce bone pain, decrease bone destruction and so likely decrease the risk of pathologic fracture. Bone Tumors In Greyhounds Primary bone neoplasms are common in dogs. It involves the processes of bone deposition or bone production done by osteoblasts and bone resorption done by osteoclasts, which break down old bone. Use the menu below to choose the Introduction section to get started. Each of the four primary forms of bone cancer, osteosarcoma, Ewing's sarcoma, chondrosarcoma and spindle cell, have been known to metastasize in the femur. The most common symptom of bone cancer is pain in a bone or joint that doesn't go away and may be made worse by exercising. This is project is mainly focused on fabrication and impact analysis of femur bone and replacing it in place of the damaged bone. Bone Fractures in Cancer Patients and Survivors A spinal fracture (also called a vertebral compression fracture ) occurs when one of the bones of the spinal column fractures. lung or breast; cancer affecting bone of hip likely to affect other bones e. Procedures to kill cancer cells with heat or cold may help. The femur bone is the long thigh bone. total femur replacement after neoplastic involvement of the bone. The disease is extremely aggressive and has a tendency to spread rapidly into other parts of the dog's body ( metastasize ). Surgically related problems occur in approximately 20% to 30% of cases. Knee pain has multiple causes, the most common being osteoarthritis, particularly in the older population. The knee joint is made up of three bone surfaces: The femur (thigh bone), with the knee end of the femur forming two cartilage-covered compartments known as the femoral condyles; Patella (kneecap) Tibia (shin bone) Figure 1: Anatomy of the Knee. Anderson Cancer Center Date: April 9, 2012 [ Background Music ] Lisa Garvin: Welcome to Cancer Newsline, a podcast series from the University of Texas M. Shop Femur Mouse Pads from CafePress. In 2009 I underwent a total hip replacement of my right hip due to osteonecrosis. Metastatic Disease of the Proximal Femur intramedullary nails, standard endoprosthesis, and customised or replacement endoprosthesis. Purpose of a bone scan: 1. What Breast Cancer Survivors Need To Know About Osteoporosis | NIH Osteoporosis and Related Bone Diseases National Resource Center. He is scheduled to have surgery this week to implant metal stabilization hardware in the femur and might need hip replacement as well, depending on the femur's condition once the orthopedic oncology surgeon gets in there. 1 knee patient had 1-stage revision surgery with replacement of a Mega C distal femur tumor prosthesis due to deep infection 1. leukaemic or myeloma infiltration of the bone marrow, or due to secondary metastases from another site e. A primary bone cancer actually begins in bone—while a secondary bone cancer begins somewhere else in the body and then metastasizes or spreads to bone. Osteoporosis and Hip Fractures Osteoporosis is a marked loss of bone mass, resulting in porous and brittle bones. I'm coming up on seven (7) months and although this is a rare form of cancer and surgery I am having significant pain in my patella. Bone death, or osteonecrosis, occurs when a bone does not heal and becomes infected and fractured after a minor trauma. Skin grafts, if necessary. Anderson Cancer Center. 3 years after implantation. to detect bone cancer or detect if cancer from another part of the body has spread. Spondylolysis. More information on Bone Cancer, causes and treatments, Click Here Consider a donation today so that we can help many more bone cancer patients fight this disease. At the U-M Rogel Cancer Center, treatment of bone metastasis takes place in the clinic where the originating cancer is treated. Due to the high mechanical forces directed through the hip, surgery is often required for pain palliation, to restore function and to allow immediate unrestricted weight bearing. It can be defined as a lymphoma that occurs in the bone, consisting of a single bone lesion with or without regional lymphadenopathies, and its underlying causes are largely unknown. In cases of small lesions involving less than one-third of the surface of the femoral head, rotational osteotomy has been very successful. According to the Canadian Urological Association Journal, SREs is when bone metastases have: cause compression of the spinal cord, cause bone fractures, surgical treatment for bone, need for radiation illness or impending fracture treatment, and The incidence and mortality of prostate cancer in the United States. Lung cancer is the third most common form of cancer to spread to bones (after breast cancer and prostate cancer), and when metastases to bone are found without an obvious source, half of the time it is related to an underlying lung cancer. So, you may gain a few pounds of body weight as a result of hip replacement surgery. Tibia (shin bone) near the knee. The cause is not known but doctors believe it. The Femur: Part of the Hip Joint. Across a wide variety of tumors with bone involvement, the frequency of SREs can be reduced through use of osteoclast inhibitors such as bisphosphonates or denosumab. Cancer and its treatment may disrupt this activity and compromise bone health. Ewing sarcoma is the second most common type of bone cancer, comprising about one-third of cases in the United States. The ball is replaced with a metal ball that is fixed solidly inside the femur. Cancer in the bone may cause severe pain for a while before the bone actually breaks. 2 - 4 Its estimated incidence is one in 100,000 among persons 10 to 19 years. For example, if you are an older adult, osteoporosis increases your risk for fracturing your femur. Primary bone cancer is rare, making up around 0. These drugs are also given to cancer patients for the prevention of fractures due to bone metastases. The most unfortunate aspect of bone cancer, or any type of cancer, is that patients often don’t realize there is an issue until it’s too late. femur in cases of destructive bone tumour or after wide resection may be similar to that when excessive bone loss arises due to loosening of the stem after total hip replacement (THR). Normal conversion of red to yellow marrow occurs in a predictable and progressive manner. Each guide is reviewed by experts on the Cancer. Data on clinical-pathology, skeletal outcomes and bone. This is the most common complication of hip replacement and occurs when the shaft of the prosthesis becomes loose in the socket of the thigh bone or the bone surrounding the implant starts to thin. But I fear things may be coming to a head as the infection is now in the top of the joint, in my femur. Among other things, the spread of the prostate cancer to the bones (bone metastases) can cause severe pain and fracture, and hormonal therapy for prostate cancer can cause bone loss, fracture, and joint pain. the bone that extends from the pelvis to the knee, being the longest and largest bone in the body; its head articulates with the acetabulum of the hip bone, and distally, the femur, along with the patella and tibia, forms the knee joint. Generally, these types of femur fractures are very uncommon and. We conducted a large, multicenter, retrospective survey aimed to explore the impact of tumor bone involvement in Non-Small Cell Lung Cancer. TABLE 1: Causes of Bone Marrow Signal Alteration in the Extremities Analysis of marrow abnormalities is based on a pattern approach that includes an evaluation of the distribution, location, signal characteristics, and morphology of the entity. osteosarcoma is the most common bone cancer in children. Bone bruising was a phenomenon that was not observed prior to magnetic resonance imaging, according to the International Society of Arthroscopy, Knee Surgery & Orthopaedic Sports Medicine. Osteoblastic metastases often happen when prostate cancer spreads to the bone. Knee pain has multiple causes, the most common being osteoarthritis, particularly in the older population. Broken Femur Healing Times. 37 Nearly 80% of patients have abnormalities in bone radiographs at diagnosis and up to 90% of patients develop bone complications over the disease course. The top of your femur and part of your pelvic bone meet to form your hip. The tibial endoprosthesis is a limb sparing surgery that replaces a section of bone affected by a bone tumour to prevent the need for full limb amputation. Further, this is a treatment for bone cancer, which can strike young people. Cancer cells that have spread to the bone can damage the bone and cause symptoms. They’re just a band-aid – to make your dog feel comfortable for a while, until the treatments end and the cancer takes over again… And that’s not good enough for you and your dog. Proximal femur replacement using the so-called “mega-prostheses” is an alternative option in cases of severe proximal femoral bone loss[49,50] (Figure 10). to get the total femur replacement with a specific prosethesis. Because people with OI face frequent periods in a cast due to surgery or fractures, steps should be taken to prevent immobilization osteoporosis. Rajeev K Sharma performs rare total femur replacement surgery on Uzbekistan patient at Apollo Hospital February 11, 2015 / jayashankarmenon After undergoing three failed surgeries to treat multiple point recurrent cancer on the leg bone in Uzbekistan, 24 year old SobidjOn Juraev lost all hope of ever leading to a normal life. Primary bone cancer is rare, making up around 0. Bone cancer in dogs and cats can be a challenging disorder to overcome. This is also known as primary bone cancer. This is more serious than a hip replacement in terms of recovery, probably around 8 weeks to be near normal in terms of walking. Their use will reduce bone pain, decrease bone destruction and so likely decrease the risk of pathologic fracture. Anterior approach hip replacement surgery is an advanced surgical technique in which an incision is made in the front of the hip rather than the side or back of the hip, as is done with traditional hip surgery. State Of Development. Tumors and cancer can cause either type. Bone disease is a key feature of multiple myeloma. Amputation, in severe cases. The 30 plus synovectomies and a Yttrium injection had destroyed too much bone to be viable for a TKR. The X-Ray showed a large tumor in my right distal femur. Assessing the risk of bone fracture due to disease (osteoporosis, cancer) or special circumstances (space travel), as well as evaluation of patients’ responses to medications in pharmaceutical studies and clinically; bone remodeling predictions due to prostheses. The Rothman Institute at Thomas Jefferson University, joseph. Replacement of bone is done firstly by designing the bone, secondly by analysing its properties and its characteristics. Thanks to effective advertising, many people assume that joint pain is caused by arthritis, but it can also occur as a result of cancer treatment and, although not life-threatening, can cause serious distress. The excessive bone growth forms a bump, which can do one or both of the following: Prevent the femoral head from fully rotating in its socket. The most unfortunate aspect of bone cancer, or any type of cancer, is that patients often don't realize there is an issue until it's too late. Many times, bone graft is used in revision surgery. 859 is grouped in the following Diagnostic Related Group(s) (MS-DRG V35. Anderson Cancer Center. Journal of Clinical and Experimental Orthopaedics focuses on the areas such as age and cancer related bone degeneration, orthopedic oncology, pediatric orthopedics, osteoporosis, foot and ankle surgery, knee replacements, hip replacement, osteopenia, joint replacement treatment of arthritic, etc. In healthy individuals, breaks and fractures to the femoral bone are typically the result of blunt force trauma , most commonly from the forceful impact sustained during a serious car accident. According to the Canadian Urological Association Journal, SREs is when bone metastases have: cause compression of the spinal cord, cause bone fractures, surgical treatment for bone, need for radiation illness or impending fracture treatment, and The incidence and mortality of prostate cancer in the United States. They say femur replacement is the only alternative. leukaemic or myeloma infiltration of the bone marrow, or due to secondary metastases from another site e. Helpful, trusted answers from doctors: Dr. •Osteoblasts of a benign osteoblastoma are identical. A broken femur can be an extremely painful and inconvenient occurrence. Osteosarcoma most often affects the long bones, such as those in the arms and legs. The narrowed region below the head is the neck of the femur. Radiation therapy. Bone replacement therapy is a well-established science. Due to the size and strength of the femur, a significant force is required to break or fracture the bone. For this reason, the exact number of spindle cell sarcoma of the bone cases is still largely unknown, though it is reported that they make up just 2-5% of all primary bone cancer cases. Templeton 1 , Michael H. It is a rare disease in which cancer cells are found in the bone or in soft tissue. 02 Major dysfunction of a joint(s) (due to any cause) : Characterized by gross anatomical deformity (e. Start studying Ch 64 - Bone Tumors/Cancer. After many testings, the conclusion is that I have a stress riser or facture at the apex (end) of the femur implant. Thanks to effective advertising, many people assume that joint pain is caused by arthritis, but it can also occur as a result of cancer treatment and, although not life-threatening, can cause serious distress. Nooo way (it doesn't have to be cancer)! It could be nothing! I had a hip x-ray with a shadow and it turn out to be nothing too bad. A primary bone cancer actually begins in bone—while a secondary bone cancer begins somewhere else in the body and then metastasizes or spreads to bone. Spinal compression fractures can be caused by many things. The most common locations for osteoporosis-related fractures are in the hip, spine, and wrist. Osteosarcoma refers to the most common bone tumor found in dogs. I had Stage 2 Osteosarcoma, or bone cancer. Secondary bone cancer is the most common form of bone cancer and is caused by the spread of cancer cells from a cancer somewhere else in the body, such as the breast, prostate or lungs. I never smoked but have been overweight most of my life. A bone scan (left) shows extensive cancer in right thighbone (femur). He is scheduled to have surgery this week to implant metal stabilization hardware in the femur and might need hip replacement as well, depending on the femur's condition once the orthopedic oncology surgeon gets in there. The cancer cells may settle in that part of the body and then form a new tumour. The head of the femur is semi-dome shaped bone that rests in the hip. Primary bone cancers are called sarcomas. Broken bones. The leg movement can be restricted due to the condition that will be the focus of this article and it is called bone spur in knee. Introduction. If this happens, it's called a secondary cancer or a metastasis. The bone becomes very dense, or sclerotic. Running would take longer. I survived Stage 4 squamomous head and neck cancer in 1999 with a head and neck dissection and just had a recurrence near my left tonsil last month. This form of bone cancer appears most commonly in the shafts of long bones, such as the femur, tibia, or humerus, or in the ribs or flat bones of the pelvis, scapula, or skull. Although my hip pain is gone, I am have extreme pain in my aterior femur bone, along with pain still from t This topic is answered by a medical expert. About Dog Bone Cancer. It usually occurs near the ends of the bones where the fastest growth is taking place (growth plates). The tolerance dose for the adult human femur (thigh bone) is said to be 38 to 43 Gy. Children with retinoblastoma have a high risk for osteosarcoma in adolescence. Surgery is often the main treatment for bone cancer. 43 - Asept necro femur condyl (Approximate Flag. The present study describes a case of diffuse large B‑cell primary non‑Hodgkin lymphoma of the bone, which occurred in the right femur, and was initially treated with surgery and chemotherapy. Bone Cancer Mistake #2: The Limits of Conventional Dog Cancer Care. Bone Cancer Surgery Options for the Adult Patients. Bone cancer is a malignant tumor that arises from the cells that make up the bones of the body. At the lumbar spine, bone densities lower than baseline were significant ( P < 0. The majority of bone tumors are noncancerous. A fracture of the upper tibia may result in injury to both the bone and the soft tissues of the knee region. The femur bone is the long thigh bone. Due to the size and strength of the femur, a significant force is required to break or fracture the bone. I am 52 years old and the cancer is estrogen driven/bone only metastasis ( a few other spots on ribs and spine) My leg is slowly healing. Most people are familiar with these drugs as osteoporosis treatments for postmenopausal women. Further, this is a treatment for bone cancer, which can strike young people. 1 knee patient had 1-stage revision surgery with replacement of a Mega C distal femur tumor prosthesis due to deep infection 1. Journal of Clinical and Experimental Orthopaedics focuses on the areas such as age and cancer related bone degeneration, orthopedic oncology, pediatric orthopedics, osteoporosis, foot and ankle surgery, knee replacements, hip replacement, osteopenia, joint replacement treatment of arthritic, etc. Anderson Cancer Center. Functions of the skeletal system The skeleton Parts of a bone Types of bone Bones and growth Roots, suffixes, and prefixes Cancer Focus Related Abbreviations and Acronyms Further Resources Functions of the skeletal system There are about 206 bones in the human body, they have the function of protecting and preserving the shape of soft tissues. to get the total femur replacement with a specific prosethesis. Ligaments connect one bone to another. For example, fractures in the subcapital region of the femoral neck frequently interrupt the major part of the blood supply to the head of the femur, which can lead to avascular necrosis. Osteosarcoma most often affects the long bones, such as those in the arms and legs. So nervous about it all. Dog bone cancer, also called Osteosarcoma, occurs in about 5% of all tumors in dogs. 14 is a billable medical code that can be used to indicate a diagnosis on a reimbursement claim, however, 733. Researchers have identified a new, highly sensitive method to assess the extent of titanium leaks from implants. Cancer that arises from the jaw bone is termed primary jaw cancer. My sister has bone marrow cancer but they say I only have arthritis. In densitometry, Ward's t. In December of 2003 I got a total femur replacement (femur, knee, hip) I was the second or third perosn in the U. Bone is the most common site for breast cancer metastases, occurring in up to 70% of those with metastatic disease. However, malignant cells can also spread to the jaw from other cancers in the neck and head, termed as secondary jaw cancer. It is a rare disease in which cancer cells are found in the bone or in soft tissue. ICD-9-CM 170. Over time, the replacement bone fuses together with the original bone, making limb movement possible. Accordingly, the patient with a pathological fracture of the proximal femur with advance lung cancer in extremis should be expediently stabilized whereas a patient with renal cell carcinoma who is otherwise well may require a hip replacement (Nathan et al, 2005). Most periprosthetic fractures occur after a patient has been living with a hip replacement for several years. Templeton 1 , Michael H. If the bone is deprived of blood for an extended period of time, it will collapse, destroying the bone and disrupting use of the joint. Achieving and maintaining good health is a balancing act. time for OI bone is normal. com - 3D medical animation from MediVisuals Inc. Numerous mechanisms may result in the loss of proximal femoral bone stock in a patient who has undergone total hip arthroplasty (THA), including infection, mechanical loosening, osteolysis secondary to particle debris, stress-shielding with adaptive bone remodeling, periprosthetic fracture (Figures 1a and 1b), and nonunion (Figures 2a and 2b).