Vertebroplasty and Kyphoplasty

Background. There are 28 million Americans with osteoporosis or osteopenia, resulting in 1.5 million fragility fractures per year with direct health care costs of approximately $13 billion(1). About 700,000 of these fractures are vertebral compression fractures, of which about 270,000 are clinically diagnosed(2). New vertebral fractures that are not clinically detected nevertheless cause a two to three-fold increase in back pain and functional limitation(3). Five percent of 50 year-old women and 25% of 80 year-old women have had at least one vertebral fracture(4). Clinical consequences of vertebral compression fractures include pain, loss of height, deformity, reduced pulmonary function(5), disability, diminished quality of life(6), and a 15% increased mortality rate(7).

Treatment of vertebral fractures. Conventional medical therapy for vertebral fractures includes bed rest, narcotic analgesics, salmon calcitonin, external back bracing, physical therapy, hospitalization, and skilled nursing care. Unfortunately, medical management of painful fractures may itself compound the problem, since lack of mobility can increase the rate of bone demineralization and increase the risk of additional fractures(8). Although most patients respond to conservative treatment and heal within weeks or months, a minority of patients continue to suffer pain. When there is concurrent spinal instability or neurologic deficit, open surgery with fracture reduction and stabilization has been used. Due to the high risk of surgery, minimally invasive techniques, such as vertebroplasty and Kyphoplasty(tm) have been developed.

Vertebroplasty.This procedure was first performed by interventional radiologists in France in 1984, and in the USA in 1995. The minimally invasive procedure involves the high-pressure injection of bone cement (polymethylmethacrylate) through a 10 or 11 gauge needle through both pedicles into the vertebral body, usually using biplane fluoroscopic control(9). Vertebroplasty has been used to treat fractures caused by osteoporosis, metastatic tumors, multiple myeloma and vertebral hemangiomas(10). It is a safe and effective method of treating disabling pain in selected patients who are refractory to conservative measures. Pain relief often occurs within one hour of the procedure, which can be performed with local, regional, or general anesthesia. In a series of 80 patients with osteoporotic vertebral fractures treated and followed for one month to ten years, more than 90% had immediate results that were excellent, with complete relief of symptoms within 24 hours(11). There was one complication– an intercostal neuralgia treated by local anesthetic infiltration. In another study(12), 29 patients with 47 osteoporotic vertebral fractures were treated over a period of three years. Twenty-six (90%) of patients treated experienced pain relief and improved mobility with 24 hours after treatment. The only clinical complications were two nondisplaced rib fractures resulting in limited chest pain which subsequently resolved. As many as 7 vertebral bodies have been injected in one patient, with excellent results(13).

Indications: Painful osteoporotic vertebral fracture(s) refractory to medical therapy; associated major disability (failure to walk, transfer, or perform activities of daily living); painful vertebral fracture or impending fracture related to benign or malignant tumor; painful vertebral fracture associated with osteonecrosis; unstable compression fracture that demonstrates movement at the wedge deformity; conditions where reinforcement of the vertebral body or pedicle prior to a posterior stabilization procedure is desired; patients with multiple compression deformities from osteoporotic collapse in whom further collapse would result in pulmonary or GI compromise; chronic traumatic fractures in normal bone with non-union of fracture fragments

Absolute contraindications: Asymptomatic stable fracture; patient clearly improving on medical therapy; no evidence of acute fracture and no planned spinal destabilization procedure; osteomyelitis of target vertebra, acute traumatic fracture of non-osteoporotic vertebra; uncorrectable bleeding disorder.

Relative contraindications: Radicular pain significantly in excess of vertebral pain; retropulsed fragment causing significant spinal cord compromise; tumor extension into the adjacent epidural space with significant spinal cord compromise; very severe vertebral body collapse (>70%); stable fracture known to be more than two years old.

Risks: Infection; transient or permanent neurological deficit; transient or permanent radicular pain; pulmonary cement embolus; epidural cement embolus; rib fracture; allergic/idiosyncratic reaction.

Benefits: Pain relief and fracture stabilization.

Kyphoplasty(tm). Kyphon Inc. has developed a bone tamp which can be inserted through a small cortical window in the vertebral body or pedicle and inflated to reduce vertebral compression fractures. The procedure can create a void in the trabecular bone and restore vertebral body height, thereby allowing a stabilizing material to be injected under low pressure. This device is similar to other devices that have been used for other types of fractures for many years, and on this basis received FDA approval in 1998. Preliminary reports have shown that this procedure is similar to vertebroplasty in safety and efficacy, with the added benefit of vertebral fracture reduction and partial reversal of skeletal deformity. A randomized controlled study is now underway at approximately 30 centers in the USA, comparing Kyphoplasty(tm) to conventional medical therapy for the treatment of acute osteoporotic vertebral fractures.

Indications, Contraindications & Risks: Similar to vertebroplasty, although Kyphoplasty(tm) can be expected to have the greatest potential to correct skeletal deformities in the setting of an acute, rather than chronic, vertebral compression fracture.

Benefits: Pain relief, fracture stabilization, fracture reduction, correction of skeletal deformity.

References:
1. Ray NF, Chan JK, Thamer M, Melton LJ III. Medical expenditures for the treatment of osteoporotic fractures in the United States in 1995: Report from the National Osteoporosis Foundations. J Bone Miner Res 1997;12:24-35.
2. Cooper C, Atkinson EJ, O’Fallon WM, Melton LJ III. Incidence of clinically diagnosed vertebral fractures: a population-based study in Rochester, Minnesota, 1985-1989. J Bone Miner Res 1992;7:221-7.
3. Nevitt MC, Ettinger B, Black D, Stone K, Jamal SA, Ensrud K, Segal M, Genant HK, Cummings SR. The association of radiographically detected vertebral fractures with back pain and function: a prospective study. Ann Int Med 1998;128(10):793-800.
4. Melton LJ III, Kan SH, Frye MA, Wahner HW, O’Fallon WM, Riggs BL. Epidemiology of vertebral fracture in women. Am J Epidemiol. 1989;10:283-96.
5. Schlaick C, Minne HW, Bruckner T, Wagner G, Gebest HJ, Grunze M, Ziegler R, Leidig-Bruckner G. Reduced pulmonary function in patients with spinal osteoporotic fractures. Osteoporos Int 1998;8:261-67.
6. Cortet B, Houvenagel E, Puisieux F, Roches E, Garnier P, Delcambre B. Spinal curvatures and quality of life in women with vertebral fractures secondary to osteoporosis. Spine 1999;24(18):1921-25.
7. Kado DM, Browner WS, Palermo L, Nevitt MC, Genant HK, Cummings SR. Vertebral fractures and mortality in older women: a prospective study. Arch Intern Med 1999;159:1215-20.
8. Heaney RP. The natural history of osteoporosis: Is how bone mass an epiphenomenon? Bone 1992;18(3):S23-26.
9. Garfin S, Mermelstein L, Mirkovic S, Sandu H, Vaccaro A. Challenges of spine fixation in the adult. Presented at the North American Spine Society meeting, October 31, 1998.
10. Cotton A, Boutry N, Cortet B, Assaker R, Demondion X, Leblond D, Chastanet P, Duquesnoy B, Deramond H. Percutaneous vertebroplasty: state of the art. Radiographics 1998;18:311-20.
11. Deramond H, Depriester C, Galibert P, Le Gars D. Percutaneous vertebroplasty with polymethylmethacrylate: technique, indications and results. Radio Clin North Am 1998;36:533-46.
12. Jensen ME, Evans AJ, Mathis JM, Kallmes DF, Cloft HJ, Dion JE. Percutaneous polymethylmethacrylate vertebroplasty in the treatment of osteoporotic vertebral compression fractures: technical aspects. AJNR 1997;18:1897-1904.
13. Mathis JM, Petri M, Naff N. Percutaneous vertebroplasty treatment of steroid-induced osteoporotic compression fractures. Arth Rheum 1998;41(1):171-5.