Orthopedic Surgery Grand Round 7th February 2013 Dr. J.W. Kinyanjui Registrar Ward 6D Outline Introduction Epidemiology Pathophysiology Clinical evaluation Management Introduction Fracture through abnormal bone Minor trauma or during normal activity 5th decade most prevalent Metastases 2nd most common cause of pathologic fractures F: breast and lungs – 80% M: prostate and lungs – 80% 10% - no primary tumor found Epidemiology – incidence at autopsy Primary Site Breast Lung Prostate Hodgkin’s Kidney Thyroid Melanoma Bladder % metastasis to Bone 50-85 30-50 50-70 50-70 30-50 40 30-40 12-25 Pathophysiology Most spread is hematogenous Few tumors due to contiguous spread Most common osteolytic via osteoclast stimulation Prostate – commonly osteoblastic Breast – mixed Theories explaining predilection of bone for metastasis Paget’s fertile soil hypothesis 1889 Sites of secondary growths are not a matter of chance Some organs provide a more fertile environment for the growth of certain metastases Example: breast cancer to liver, Krukenberg tumor Prostate cancer to bone Hart and fielder later proved this using radioactive labelling Ewing’s circulation theory 1928 Metastatic deposits dependent on route of blood and lymph flow Organs though to be passive receptacles Organs with prominent venous systems have more secondaries Baston plexus of spine responsible for prostate secondaries Red marrow theory In descending order of frequency: Spine Pelvis Ribs Proximal appendicular skeleton Marrow sinusoids more susceptible to tumor cell penetration Sudden change from arterioles to sinusoids favours tumor cell entrapment Ewing’s and Paget’s theories not mutually exclusive Molecular level Cells from primary enter blood vessels Attachment and penetration of basement membrane, neovascularisation Type 1 collagen shown to be chemotactic to tumor cells RANK ligand produced by tumor cells stimulating osteoclast activity PTHrP produced by breast and lung cancer cells stimulates osteoclasts Prostate cancer cells produce BMPs, IGF1, TGFβ2 which stimulate osteoblasts Clinical evaluation: History Pain – most common, preceding fracture, night, constant, dull, aggravated by activity Trauma – usually minimal for type of fracture Constitutional – anorexia, night sweats, weight loss, fatigue Previous cancer Carcinogen – smoking, radiation, occupational toxins Factors suggesting pathologic fracture Spontaneous fracture Minor trauma Pain at site preceeding fracture Multiple recent fractures Age > 45 yrs Prior history of malignancy Associated problems Lowered Quality of life: Debilitating pain Immobility Neurologic deficits – spine mets Anaemia Hypercalcemia Hypercalcemia Neurologic: headache, confusion, irritability, blurred vision Gastrointestinal: anorexia, nausea, vomiting, abdominal pain, constipation, weight loss Musculoskeletal: fatigue, weakness, joint and bone pain, unsteady gait Urinary: nocturia, polydypsia, polyuria, urinary tract infections Clinical evaluation: examination Local: mass, deformity, tenderness, contiguous skeleton, neurologic exam Systemic: cachexia, pallor, lymphadenopathy, entire skeletal system Primary: breast, thyroid, prostate, lung, pelvic Clinical evaluation: Laboratory TBC – anaemia of chronic disease Calcium – elevated Alkaline phosphatase – elevated, non specific Tumor markers – PSA, CEA, CA125, TFTs N-telopeptide + C-telopeptide – markers of bone destruction, determine extent of skeletal involvement, assess response to bisphosphonates Imaging: plain radiographs Enneking’s questions: Location: diaphysis, metaphysis, epiphysis, cortical or medullary Effect: osteoblastic vs. osteolytic or mixed Reaction: sclerotic rim, periosteal reaction, codman triangle Isolated avulsion of lesser trochanter – imminent femoral neck fracture Osteolytic, diaphyseal medullary, periosteal reaction Osteoblastic mets to bone Codman triangle Osteolytic lesion in lesser trochanter Radiology: CT scans Most sensitive for detecting bone destruction Determines extent of cortical involvement Also used to search for primary lesion in pelvis, abdomen or chest Mixed lesion in lung mets Radiology: MRI Most sensitive for assessment of the anatomic extent of a lesion Most adequate for spinal metastases to determine neurologic structure involvement Can determine extraosseous spread of a mass Bone scanning Technetium-99m (99m Tc) bone scanning: Sensitive for detection of occult lesions Assessment of the biologic activity of lesions Identification of other sites Assessing response to therapy Biopsy Indicated to rule out primary tumor of bone Immunohistochemistry can determine primary Biopsy at fracture site complicated by bleeding and callus formation Needle vs incisional Oncological surgical principles adhered to Cultures to rule out infection Impending pathologic fractures Prophylactic stabilisation before radiotherapy can be performed for pain Radio and chemotherapy without stabilisation also an option Decision to stabilise difficult Mirel’s criteria useful to determine which lesions at high risk of fracture Mirel’s criteria VARIABLE SCORE SITE Upper Limb Lower Limb Peritrochanteric PAIN Mild Moderate Severe LESION Blastic Mixed Lytic SIZE <1/3 1/3 – 2/3 >2/3 Size is the diameter of cortex involved on plain radiographs A score of 8 or more is an indication for prophylactic stabilisation Advantages Prophylactic stabilisation: Shorter hospital stay More immediate pain relief Faster and less complex surgery Quicker return to premorbid function Improved survival Management objectives Decrease pain Restore function Maintain/restore mobility Limit surgical procedures Minimize hospital time Early return to function (immediate weightbearing) Non operative management Bisphosphonates – modifies bone resorption by osteoclasts, shown to reduce risk of skeletal metastasis Hematologic – correction of anaemia, coagulopathy, DVT prophylaxis Hypercalcemia – hydration, calcium restriction, bisphosphonates, mithramycin Analgesia Radiation – most useful in spinal metastases Radiotherapy Used to reduce pain secondary to bone metastases Partial in 80%. Complete in 50 – 60% Halts progression of bony destruction Allows healing of an impending pathologic fracture Postoperative local tumor control Bracing Patients with limited life expectancies, severe comorbidities, small lesions, or radiosensitive tumors Upper extremity lesions particularly amenable Adjuvant radiotherapy of suscepible tumors required Operative: principles Durable, weight bearing impalnts needed PPMA augmentation of construct useful incl. prosthesis Bone graft less useful due to prolonged healing time Prophylactically stabilise as much bone as possible Anticipate hemorrhage due to neovascularisation Thus tourniquet, preoperative embolisation Upper extremity Scapula, clavicle – non operative Proximal humerus – prosthesis (long stem), intramedullary nail with multiple screws Humerus Diaphysis – locked IM nail > plating Distal humerus – prosthesis, retrograde flexible IM nails > bicondylar plating Forearm – Rare. IM nails or plating Lower extremity Acetabular – reconstruction with appropriate prosthesis Femoral neck – hemi- or THR. Cemented. Long stem Intertrochanteric – recon nail or prosthesis > DHS Subtrochanteric – locked IM nail Femur shaft – locked IM nail preferably cephalomedullary Around the knee – locked plating > retrograde nailing Spinal fractures Commonly present with compression fracture MRI to differentiate from osteoporosis Lesion involving body and pedicle sparing disc highly suggestive Radiotherapy, steroids if no neurodeficits or impending fracture Spinal fractures Surgery: Progression of disease after radiation Neurologic compromise Impending fracture Spinal instability due to pathologic fracture Progressive deformity due to pathologic fracture Options: Minimally invasive kyphoplasty/vertebroplasty Decompression and instrumentation Controversies and future trends Optimal length of femoral component of THR Criteria for impeding fracture Wide resection of solitary metastases – RCC Radiofrequency ablation Cryotherapy Acetabuloplasty – percutaneous PMMA injection RANK L modification Angiogenesis inhibitors Summary Diagnosis and treatment requires a multidisciplinary approach Aggressive surgical treatment relieves pain, restores function, and facilitates nursing care Biopsy all solitary lesions or refer appropriately Understand tumor biology and tailor treatment THANK YOU