1.Minimally invasive technology for osteoporotic vertebral compression fractures
Osteoporosis is one of the diseases that threaten the health of the elderly. A survey points out that about 1/3 of the elderly aged 60 to 70 have osteoporosis, and more than half of the elderly aged 80 or above have osteoporosis comorbidity, and osteoporotic vertebral compression fracture (OVCF) is one of the most common crestal injuries in elderly patients. In China, there are about 90 million patients with different degrees of osteoporosis, the proportion of which is as high as 5.6%, and the proportion of thoracolumbar fractures caused by osteoporosis is more than 20%, while OVCF is obviously associated with advanced age, mostly seen in elderly people over 60 years old, especially postmenopausal women, and can cause persistent low back pain, which seriously affects life and living, causing a double blow to body and mind.
2.Osteoporotic vertebral compression fracture treatment
For the treatment of OVCF there are.
(1) Traditional methods mainly include bed rest, drug bouts, anti-osteoporosis drugs, lumbar pillow cushions, and functional forging treatment of the low back muscles, etc. These conservative treatment methods are not only ineffective, but also take a long time to treat, the adverse effects of a variety of drugs restrict the use of the population, and patients need to be bedridden for a long time, which will lead to further bone loss and accelerate the progress of osteoporosis, often causing hunchback and low back pain, and also easy to develop a variety of complications such as pneumonia and urinary tract infections.
(2) Traditional open surgery is very traumatic, with poor fixation, long fixed segments, limited mobility and restricted by the patient’s osteoporosis and poor general condition.
(3) Percutaneous vertebroplasty (PVP) is less traumatic, can be performed under local anesthesia, relatively simple, short operation time, for elderly patients can reduce the risk of surgery, and rapid pain relief, is a simple, minimally invasive, safe and effective treatment method.
3.What is percutaneous vertebroplasty
Percutaneous injection of artificial material into the vertebral body through the pedicle or directly into the vertebral body to distribute it along the trabeculae to the entire vertebral body, in order to enhance the strength and stability of the vertebral body, prevent the collapse of the vertebral body, relieve pain and even partially restore the height of the vertebral body is called percutaneous vertebroplasty (PVP), which is a new minimally invasive crestal surgery invented by the French in 1984, initially used for cervical aggressive hemangioma, and later applied to vertebral compression. PVP was first used in Europe and then in the United States, and now it is mainly used for VCF in China, and has developed greatly.
4.Indications and contraindications of PVP
(1) Indications include.
(1) compression fractures of the thoracolumbar segment of the crest without combined neurological injury caused by osteoporosis.
(ii) old crestal compression fractures with severe posterior protrusion deformity and recalcitrant low back pain caused by fracture.
③ pain symptoms that cannot be relieved after non-surgical treatment, recurrent or to prevent long-term bed-ridden complications.
④ multisegmental compression fractures of the upper and lower adjacent vertebrae secondary to osteoporotic vertebral compression fractures.
(⑤ Pain due to other causes such as lumbar disc herniation is excluded by imaging.
(2) Contraindications include.
(i) Imaging suggests that the vertebral fracture line crosses the posterior edge of the vertebral body or that the posterior edge of the vertebral body is bony and incomplete.
(ii) The degree of compression of the vertebral body exceeds 75%.
③ coagulation disorders with bleeding tendency.
④ extreme physical weakness unable to tolerate surgery.
⑤ hyperlipidemia and history of lower limb or systemic vascular embolism.
5. Pain relief mechanism of PVP
Current studies mainly believe that PVP pain relief relies on.
① necrosis of nociceptive nerve endings in the vertebral body due to heat production by polymerization of bone cement
(ii) the cytotoxic and occupancy effects of bone cement reduce the sensitivity of nerve endings in the surrounding tissues and increase the pain threshold.
(iii) The vertebral body is strengthened after bone cement injection, which improves the stability of the vertebral body and reduces the compression of peripheral nerves.
Filling materials of PVP
The current PVP injection material is mainly polymethylmethacrylate (PMMA) bone cement, which is easy to operate and can quickly and effectively enhance the stiffness and strength of the vertebral body after injection into the vertebral body, and can be imaged after adding materials that are impervious to X-rays; it is the most commonly used PVP filling material, but it is not biologically active and is prone to damage to surrounding tissues due to the high temperature generated during solidification, in addition to calcium phosphate bone cement ( CPC), calcium sulfate bone cement (CSC) and hydroxyapatite bone cement (HBC), etc. CPC and HBC are biologically active, but the chance of re-fracture of the vertebral body after surgery is high, and they are less used in clinical practice.
6. Complications of PVP and their management and prevention
(1) Intraoperative complications.
① The most common complication of PVP is intraoperative leakage of perfusion, with an incidence of 20% to 73%, most of which do not cause clinical symptoms and do not require special treatment, and in a few cases, once the perfusion enters the spinal canal and intervertebral foramen through the posterior wall of the vertebral body, fracture line, and bone destruction area, it will compress the crestal medulla or nerve roots, causing severe back pain or limb sensory and motor impairment, and once leakage occurs intraoperatively, immediately stop If the patient has severe pain in the back and radiating pain in the limbs, stop the injection and use CT examination to determine the leakage of bone cement in the spinal canal or intervertebral foramen, and give dehydration, anti-inflammatory and pain relief treatment. If the symptoms do not improve, immediately decompress the vertebral plate and remove the leaking bone cement. (i) The occurrence of leakage can be reduced by appropriate infusion doses to increase viscosity, strict control of surgical indications and contraindications, and reduction of resistance to the infusion agent.
(ii) embolism, if the pressure at the time of injection causes the bone cement or fat in the bone marrow tissue to enter the vena cava system via the rich venous travel of the vertebral body it may lead to pulmonary embolism, causing the patient to die from dyspnea, tachycardia, coughing and coughing, and whistling failure; appropriate viscosity and perfusion pressure of the bone cement, prone position and pressure-raising drugs to increase the pressure in the vertebral vein can reduce the risk of embolism.
(iii) Pneumothorax accounts for 2.6% of all complications and its incidence can be reduced by careful preoperative film review and intraoperative dynamic monitoring.
(iv) Transient hypotension may be related to the toxicity of the bone cement, and intraoperative cardiac monitoring and blood gas analysis should be performed.
(⑤ Intraoperative puncture error or incorrect position may cause peripheral organ injury, rupture of the pedicle cortex, sternal fracture, dural injury, etc., which requires the operator to be familiar with local anatomical structures and improve surgical proficiency.
(2) Postoperative complications.
(1) Fracture of the adjacent vertebral body is due to PVP causing the fractured vertebral body to increase in stiffness and form a significant gradient difference with the adjacent vertebral body, accelerating disc degeneration and inducing vertebral body fracture.
②Patients with aggravated postoperative pain symptoms can take oral NSAIDs or steroids for pain relief if CT examination excludes cement leakage and secondary fractures of adjacent vertebral bodies, which are mostly due to thermochemical inflammation caused by exothermic reaction to cement polymerization.
(iii) Prevention of infection then requires a strict concept of asepsis.