Introduction: Scope and Purpose
Osteoporosis is a common disease that is characterized by structural deterioration of bone architecture and manifests itself as fragility fractures occurring at multiple skeletal sites, most commonly involving the spine, hip, or wrist. It is increasingly recognized that osteoporosis is an important health problem because of the large affected population and the devastating impact of osteoporotic fractures on patient morbidity and mortality, as well as on societal costs. The purpose of this chapter is to highlight the clinical and socioeconomic concerns of osteoporotic spine fractures and to give an overview of nonoperative and operative treatment for patients who sustain these injuries.
The prevalence of osteoporosis in the United States is estimated to increase from approximately 10 million to more than 14 million people in 2020. Using the World Health Organization’s definition of osteoporosis, a bone mineral density (BMD) more than 2.5 standard deviations below the mean in young, normal people, approximately 30% of postmenopausal white women in the United States have osteoporosis. Prevalence rates are lower when bone density is assessed at a single skeletal site, and it is estimated that 16% to 20% of this population has osteoporosis of the lumbar spine. Historically, fragility spine fractures in men were thought to be uncommon. However, recent population-based studies show an unexpectedly high frequency of vertebral fractures in men. It is now estimated that men account for more than 25% of the burden of osteoporosis-related fractures in the United States.
Cooper and colleagues reported that the overall age- and sex-adjusted incidence of vertebral fractures to be 117 per 100,000 and that altogether, 25% of women 50 years of age or older had one or more vertebral fractures. This rate is consistent with the 20% reported in an Australian population, 21% reported in a random sample of 70-year-old Danish women, and the 24% documented among elderly white women from other longitudinal studies. The U.S. population 50 years of age and older is predicted to increase by 60% between 2000 and 2025, eventually reaching 120 million people, which will undoubtedly cause a rise in the number of people affected by osteoporotic fractures.
Unlike fractures of the hip and forearm, spine fragility fractures are often not associated with a fall or trauma. It is estimated that only 30% of osteoporotic vertebral fractures come to clinical attention, and many are incidentally found on routine imaging studies. Unfortunately, many of these patients present with a substantial increase in back pain that often causes significant morbidity. Even if the acute pain of a spinal fragility fracture subsides, many patients develop irreversible spinal deformity, usually an increase in kyphosis, that is associated with significant health consequences, including decreased physical functioning (sarcopenia) and health-related quality of life (HRQOL), chronic back pain, impaired balance, and increased subsequent falls. Another concerning finding is that patients who have one or more vertebral fracture at baseline are five times more likely to develop another spinal fragility fracture compared with patients without prevalent vertebral fracture at baseline.
For most patients, pain and its effect on physical function are the leading cause of morbidity associated with these fractures. A recent prospective observational study showed that radiographically detected vertebral fractures were associated with long-term substantial increases in back pain and back-related disability compared with before fracture. After adjustments for covariates, women with a fracture had a 2.4 times higher risk for increased back pain compared with women without a fracture during the 4-year follow-up period. Furthermore, the annual rate of days of bed rest was nine times higher in women with a first incident fracture, and the rate of limited activity days was approximately twice has high compared with the control group. Based on their data, the authors estimated an additional 10 days per year of limited activity because of back pain in the fragility fracture group. This is comparable to the days of limited activity for patients with diabetes (15 days), ischemic heart disease (15 days), and arthritis and rheumatism (7 days).
Osteoporotic fractures have a significant impact on HRQOL. Hallberg and colleagues found that HRQOL was significantly lower for all domains, physical and mental, at the 3- and 24-month follow-up after osteoporotic fractures in women 55 to 75 years of age. Moreover, vertebral fractures have a considerably greater and more prolonged impact on HRQOL than hip, forearm, and humerus fractures.
Osteoporotic spine fractures are also associated with an increased risk of death. Lau and colleagues reviewed Medicare claims from 1997 through 2004 and found that the overall mortality rate after a vertebral fracture was twice that of the matched control participants. The survival rates after a fracture diagnosis, as estimated with the Kaplan-Meier method, were 53.9%, 30.9%, and 10.5% at 3, 5, and 7 years, respectively, and were significantly lower compared with control participants. The mortality risk was greater for men than women, and the overall difference in mortality was greatest when the patients were younger at the time of fracture. Kado and colleagues showed that women with at least one new fracture have an age-adjusted 32% increased risk of death compared with those without incident vertebral fracture. They concluded that this increased risk of death is explained in large part by associated weight loss and markers of decreased physical function. Mortality risk is 25% greater after spine fracture than hip fracture.
Osteoporosis, and in particular osteoporotic spine fractures, has a great socioeconomic impact and therefore has become an important public health problem and concern. In 2005, fragility fractures in the United States resulted in 2.5 million medical office visits, 430,000 hospital admissions, and 180,000 nursing home admissions. Their direct cost was $17 billion. The projected increase in the elderly U.S. population will likely cause this economic burden to significantly increase over the next several decades. Therefore, healthcare professionals need to focus on identifying patients at risk for osteoporosis and use evidence-based treatment strategies to prevent fractures in an ultimate effort to decrease the morbidity and mortality associated with these fractures. In select patients who fail nonoperative treatment, surgical intervention may be indicated.
Mechanism of Injury and Biomechanics
There is a general loss of bone mass with age; therefore, osteoporosis represents an extreme form of the normal aging process. The clinical manifestation of osteoporosis is fracture of the axial or appendicular skeleton (or both). Although extremity fractures are usually related to falls, approximately half of spinal fragility fractures are “spontaneous” without a traumatic event. A fracture occurs when the forces applied to the vertebrae exceed its strength. Therefore, factors related to skeletal fragility and spinal loading play important roles in their development.
In general, the ability of cortical bone to resist fracture deteriorates with aging. Several studies have indicated that although the elastic properties of cortical bone decrease modestly with age, the strength and toughness decrease more substantially. The porosity of cortical bone increases significantly with aging, and porosity is negatively correlated with bone material properties. This leads to a loss of stiffness, strength, and toughness. Unlike the appendicular skeleton, which is composed primarily of cortical bone, the axial skeleton or vertebral column is predominantly trabecular in nature. The mechanical properties of trabecular bone (modulus and strength) are most affected by apparent density, or bone mass. The apparent density of trabecular bone decreases markedly with aging in both men and women. The loss of bone mass is the most significant contributor to an increase in fracture risk, but there are also changes in the microarchitecture, tissue properties, and levels of microdamage that significantly affect the strength of the vertebra. Increasing bending forces from kyphosis may significantly increase fracture risk in osteoporotic patients.
The compressive strength of vertebral trabecular bone decreases by approximately 70% from 25 to 75 years of age. There is a reduction in the thickness and number of individual trabeculae, which leads to microstructural damage and weakening of the trabecular bone. Further, horizontal trabeculae are preferentially lost. This results in a more anisotropic structure, which has a greater susceptibility to fracture. Transverse trabeculae are preferentially thinned and perforated while the remaining vertical trabeculae maintain their thickness. This structure is likely to be more susceptible to buckling under normal compressive loads and has a decreased ability to withstand unusual or off-axis loads.
Other age-related changes contribute to spinal fragility fractures, including intervertebral disc degeneration and changes in neuromuscular function. The intervertebral discs play an important role in distributing forces that are transmitted to the vertebral bodies. With increasing age, the intervertebral disc is subject to the degenerative cascade, including dehydration of the nucleus pulposus, fibrosis of the annulus, and osteophyte formation, which disables the disc to distribute compressive forces evenly. As a result of this altered stress distribution, the anterior vertebral body is stress shielded during normal erect posture but severely overloaded when the spine is flexed. Therefore, the anterior vertebral body becomes vulnerable to osteoporotic fracture. It is important to note that altered stress distribution is also often caused by spinal fusion procedures. The abnormal stress that is placed at the adjacent level leads to an increased risk of developing an osteoporotic fracture at the adjacent segment.
Significant changes in neuromuscular function also play a role in the development of osteoporotic spine fractures. Muscular strength decreases 24% to 36% by the age of 70 years, and these changes in force production could detrimentally change the loading of the spine because antagonist muscle contraction is key for maintaining stability of the spine during flexion and extension. This reduction in intrinsic spine stability may contribute to poorer balance and postural stability, which may further contribute to falls that lead to fractures. Osteoporotic patients have associated sarcopenia, correction of which offers a management opportunity.
Evaluation
Patients who sustain osteoporotic spine fractures often present to their primary care doctors or emergency departments complaining of acute-onset back pain. A thorough spine and neurologic examination should be performed, and the entire spinal column should be palpated and inspected for areas of tenderness to palpation, as well as focal abnormalities (i.e., palpable step-offs between the spinous processes). A detailed motor and sensory examination should be documented, and the presence of any pathologic reflexes should be elicited (hyperreflexia, clonus, Babinski sign, and so on). It is rare for these patients to sustain a neurologic injury, but in such cases, an accurate motor and sensory level and degree of injury (American Spinal Injury Association Grade A–E) needs to be clearly defined.
Diagnosis and Classification
Upright biplanar plain radiographs of the spine should be the first imaging modality used to evaluate patients with a suspected osteoporotic spine fracture. An anteroposterior (AP) and lateral radiograph should be taken of the suspected area of injury based on the physical examination. If a fracture is present, the degree of vertebral body collapse and presence of focal or global deformity should be noted. A computed tomography (CT) scan should be used if the radiographs are equivocal or more detail is needed to help determine treatment. CT is much more sensitive and specific in detecting spinal column injuries compared with plain radiographs. If CT has been performed, an estimation of bone mineral density (BMD) can be made by determination of Hounsfield units, which can easily be measured using the CT software. Finally, magnetic resonance imaging (MRI) is used to determine, if necessary, the acuity of the fracture, or in the presence of neurologic compression.
Management
The majority of patients having osteoporotic spine fractures are initially treated nonsurgically, with the use of analgesics, a brief period of bed rest, initiation of osteoporosis medication, bracing, and physical therapy. It is important to mobilize these patients as quickly as possible and limit the amount of narcotic pain mediation used. In a select group of patients, cement augmentation procedures or more invasive surgical interventions may be warranted.
Cement Augmentation: Vertebroplasty and Kyphoplasty
Cement augmentation of painful osteoporotic compression fractures is the percutaneous stabilization of vertebral bodies with polymethylmethacrylate (PMMA) and more recently other ceramic alternatives. It is a common procedure with as many as 75,000 being performed annually in the Medicare population in the United States. Two techniques are widely used, vertebroplasty and kyphoplasty. Vertebroplasty was initially described for the treatment of aggressive hemangioma of the lumbar spine. It is performed through a needle, which is inserted via a transpedicular approach into the vertebral body. Liquid cement is installed under pressure to fill the fractured vertebral body, which rapidly polymerizes. Improvement in kyphotic angulation, if any, is obtained by prone positioning in extension. Kyphoplasty attempts to reduce the wedge-shaped vertebrae and thus improve kyphotic angulation by expansion of the compressed verbal body using an inflatable balloon. After vertebral body expansion, cement augmentation is performed.
Indications
The indications and timing of cement augmentation are poorly delineated, leading to variations in use and in outcomes, raising concern that the procedure is overused. This controversy was further escalated with publication of two randomized controlled trials (RCTs) that reported that vertebroplasty was no better than sham treatment. These results led to editorials in lay and peer-reviewed journals of its unproven efficacy and to withdrawal of coverage in North America as well as other countries.
The common indication is patients with painful osteoporotic compression fracture that fails to improve with time and nonoperative management. The time between fracture and consideration of cement augmentation is controversial. Most authors suggest a minimum of 3 weeks of nonoperative care, although the usual duration of symptoms of osteoporotic vertebral compression (OVC) fracture is 2 to 3 months. Another indication is in patients hospitalized for pain and functional impairment secondary to osteoporotic fractures. In these patients, cement augmentation can afford rapid improvement and has been shown to be cost effective. Other indications are in painful primary bone tumors such as aggressive hemangioma and giant cell tumors and lytic metastatic tumors with fracture or pending fracture. Finally, cement augmentation is indicated in patients with painful nonunion of a vertebral fracture, so-called Kummel disease.
Contraindications for cement augmentation include asymptomatic patients, history of vertebral osteomyelitis, allergy to bone fillers or opacification agents, uncorrected coagulopathy, or for prophylaxis. Relative contraindications are radicular pain, bone retropulsion against neural structures, greater than 70% collapse, multiple pathologic fractures of diffuse disease, and lack of surgical backup to manage complications.
Patient Selection
Because back pain is common and associated with other diseases of aging, the pain must be correlated to the fracture. Localized tenderness at the fracture site is most often present, although referred pain patterns such as low back pain for a T12 or L1 lesion can be confusing. Confirmation that a new fracture is present by a MRI, bone scan, or from serial images should be established. MRI is excellent to determine fracture acuity, pattern, and identification of adjacent occult fractures. MRI findings include increased signal intensity in the body on T2 and short tau inversion recovery (STIR) images and decreased signal on T1.
Several fracture patterns pose difficulties for cement augmentation. Kummel disease is a fracture nonunion in which a fluid-filled cleft is created within the vertebral body. Cement placement can be challenging because containment may be lacking when vertebral height has been lost. Vertebra plana occurs when more than 70% height has been lost. This is also technical challenging, but Young and colleagues have had satisfactory outcomes in such cases, although cement leakage is more common. Burst fractures or those with defects in the posterior vertebral body wall are at higher risk for cement migration into the spinal canal. Hartmann and colleagues, however, have shown that kyphoplasty is safe and feasible in 26 patients who had burst-type fractures. In these cases, kyphoplasty may be preferred over vertebroplasty to limit extravasation of cement. Other important considerations are the degree of kyphotic deformity and osteoporosis. When severe in both cases, failure may occur to either new fractures or refracture of cement at the index level.
Vertebroplasty Technique
Anesthesia and Patient Positioning.
Vertebroplasty is performed under local anesthesia and conscious sedation. Because the patient is in a prone position, careful monitoring is needed to assess the airway, ventilation, and pain. The procedure may be done in a radiology suite or operating room. The patient lies on radiolucent bolsters, which can provide some lordosis. The use of two orthogonal C-arm fluoroscopy units, obtaining simultaneous AP and lateral images facilitates the procedure. After positioning, AP radiographs are checked to ensure that the spine is squarely positioned, noting that the spinous process is exactly between the pedicles.
Pedicle Insertion.
In the lumbar spine, a transpedicular approach is used to gain access to the vertebral body. In the thoracic spine, this approach may be used if possible, but if the pedicle is too small, then a lateral extrapedicle approach will be required. The goal is to place a coaxial 8-, 10-, or 11-gauge needle down the pedicle into the fractured body below the endplate or fracture. The starting point for needle insertion is the upper outer margin of the pedicle. Using biplanar fluoroscopic control, the needle should pass into the pedicle aiming medially and caudally. On the AP view, the needle should not appear medial to the pedicle until it is positioned into the vertebral body, which occurs after 15 mm of depth. The needle is advanced until its tip is about 1 cm from the anterior cortex. On the lateral view, the needle position will vary depending on fracture morphology. The goal is to use the remaining cortical margins to “contain” the cement to avoid extravasation. The process is repeated on the opposite side. After proper needle position is ensured, the inner trocar is removed, and the cement can be inserted.
Cement Application.
The bone cement is mixed and contains barium to aid radiographic analysis. The viscosity will affect the distribution into the trabecular patterns of the vertebral body and the risk of extravasation. In general, as viscous a material as possible is injected at a slow rate under biplanar radiographic visualization. Proprietary devices are available that pressurize the cement, forcing it into the vertebral bodies. Most commonly, 2 to 3 cc of cement is inserted into each side. The trocar is replaced until the cement polymerizes, and then the needle is removed. During cement installation, imaging is critically assessed for extravasation ( Fig. 37-1 ). Extravasation will limit the amount of cement that can be placed. Common areas of extravasation are lateral, intradiscal, and anterior. Extravasation posteriorly requires aborting the procedure.
Postoperative Care.
After polymerization the patient can be mobilized without bracing or restrictions of activity. However, osteoporotic patients with or with vertebroplasty are at risk for new fracture, and medical management of this condition is an essential component of vertebroplasty care.
Kyphoplasty
Kyphoplasty is the elevation of the endplate using a balloon tamp or other mechanical devices. In addition to expanding the vertebral body, it corrects wedging of the vertebrae, reduces the kyphotic deformity, and creates a void where bone void filler can be installed. This void allows use of more viscous bone filler installed under lower pressure that theoretically may lessen risk of extravasation.
Technique.
The patient is positioned as described earlier for vertebroplasty. Although classically done under general anesthesia, kyphoplasty may be done with local anesthesia and conscious sedation. An 8- to 11-gauge coaxial needle is placed into the pedicle directed into the vertebral body. The needle is located just anterior to the base of pedicle on the lateral view. The trochar is removed, and a small Kirschner wire (K-wire) is advanced into the body and directed to within 1 cm of the anterior vertebral body. The coaxial needle is removed, and a large working cannula is inserted over the K-wire until it is just inside the vertebral body. A drill is then used to create a path in the body to within 1 cm of the anterior cortex. The balloon tamp can now be inserted through the working cannula into the body and is positioned to be anterior to the posterior vertebral body wall. The process is repeated on the opposite side.
The balloons are expanded using radiopaque solution, and the pressure is monitored. Biplanar radiographs are monitored for balloon position and the degree of correction of the deformity. Balloon expansion continues until correction is obtained, the maximum pressure is reached, or the balloon contacts the cortical margins. The balloons are then deflated and removed and replaced by cannulas filled with cement. Using hand pressure, the cement is installed into the vertebra by insertion of an obturator into the cannulas. During installation, biplane images are scrutinized for extravasation. Most commonly, 2 to 3 cc of bone filler is installed per side. After bone void filler installation, the obturators are inserted into the cannulas until polymerization has occurred. The cannulas may then be removed.
Modifications of Cement Augmentation.
Many modifications to simplify and reduce the risk of cement augmentation have been proposed. In biomechanical studies, comparison of a single-side approach versus bilateral pedicle approaches has shown that more cement can be placed using bilateral techniques but that stiffness and failure strength are not clinically significantly different. This is true for both vertebroplasty and kyphoplasty. In a cohort studies, Chen and colleagues and Wang demonstrated similar pain relief and radiographic outcomes between unilateral and bilateral kyphoplasty approaches. To provide better distribution of cement with a unilateral approach, a more lateral starting point can be used, which allows greater medial angulation. Alternatively, curved cannulas have been developed to allow unilateral cement placement. A unilateral approach decreases time, costs, and radiation exposure.
The volume of cement will change the biomechanical properties of the repaired vertebral body. Because the vertebral bone volume varies among individuals and by anatomic level (T1–L5), the absolute amount of cement that should be used cannot be stated. Mean bone volumes of intact bodies range from about 10 mm 3 at upper thoracic vertebrae to 35 mm 3 in the lower lumbar vertebrae. The amount of “fill,” percent bone volume of fractured vertebrae, appears to give best clinical results. Nieuwenhuijse and colleagues reported that responders to vertebroplasty had greater fill of up 22% than nonresponders, who had only 15%. They recommended that optimal results are obtained when the fill is 24% of the fractured vertebral body. Depending on the severity of the fracture and the fracture type, this is 3 to 4 mm 3 . Increasing cement volume increases biomechanical stiffness but also the chance of extravasation and possible adjacent-level fracture.
Radiographic morphology has an effect on specific cement techniques, indications, and outcomes. Decreased BMD reduces resistance to cement flow and possibly leads to more risk of extravasation. Furthermore, the construct is more at risk to fail because of further compression locally or at adjacent levels. This emphasizes the importance of medical management of metabolic bone disease. The presence of an intervertebral cleft most commonly occurs at the thoracolumbar junction and is an indication an unstable fracture, which often will be associated with pain. Radiographically, there is severe collapse with presence of gas inside the body and/or associated disc space. Supine and upright radiographs show significant change in height and angulation, indicating instability. MRI will show dark lines on T1 and fluid cavities of T2 and STIR sequences. In a cohort study by Nieuwenhuijse and colleagues, patient-reported outcomes were similar between patients with and without clefts, but pain relief occurs more slowly in these patients, and cement extravasation is more likely. Severe compression fractures or so-called vertebra plana produce technical difficulties to the delivery of cement. Modified techniques are needed that require the needle to be placed in a more caudal direction and use of bilateral approaches. Pain relief appears satisfactory in these severe cases, but the incidences of cement leakage and refracture are higher. With severe collapse, the posterior wall can be retropulsed into the canal with or without neurologic change. In the presence of neurologic deficits, cement augmentation should not be undertaken without adequate decompression. In patients with pain and these burst-type fractures, the use of cement augmentation is controversial. Hartmann and colleagues reported excellent outcome in 26 patients with burst-type fractures and no cement leakage into the spinal canal. Although kyphosis and vertebral body height correction was achieved initially, this was lost in most patients because of subsidence during follow-up.
Cement Formulations.
Polymethylmethacrylate- and calcium phosphate (CaP)–based cement are commonly used for cement augmentation. Recently, chemical modifications of PMMA have improved rheology properties to optimize fluid flow through the needle and to change the rate of polymerization, thus reducing temperature. A simple method to reduce the exothermic reaction is to cool the monomer with ice before mixing. In general, the use of a more viscous cement is preferable to avoid extravasation. Other formulations in testing are nanosphere particles and other compounds that may have a biologic effect on bone cells to increase bony attachment and therefore stability. Clinical outcomes showing advantages of these alternatives over PMMA are lacking. Cortoss is an approved methyl-methacrylate compound with radiopaque bioglass ceramic particles having material properties close to bone. In a randomized controlled trial, Cortoss did not show any significant improvement over standard PMMA.
Calcium phosphate cements have been approved for bone void fillers and are widely used in orthopaedic trauma and tumor reconstruction. They are intriguing bone fillers because they have the capacity for resorption and remolding and have a minimal exothermic reaction. Their use in vertebroplasty has been slow in North America because animal studies have shown that one formulation fragments after installation, resulting in embolization and hemodynamic collapse. Although used outside the United States, these compounds need critical evaluation for safety before use in osteoporotic fractures. Another concern is the biomechanical performance. CaP cement is a ceramic compound having excellent compressive strength but limited torsional and shear strength. Blattert and colleagues compared CaP with PMMA for the treatment of osteoporotic burst-type fractures and found that a third of patients treated by CaP had structural failure.
Expansion Devices.
Correction of vertebral wedging and kyphotic deformities are additional goals, which may have long-term benefits. Classically, this is accomplished with kyphoplasty using an inflatable balloon. Improvements in kyphotic angulation (3 degrees) and anterior vertebral height restoration occur after kyphoplasty compared with vertebroplasty. Other methods to expand the body include titanium and polymer meshes that maintain correction after expansion and contain the injected cement. Curved probes that can directly manipulate the endplate have been proposed as well as polymeric expandable devices. These devices are either not approved by the Food and Drug Administration or have not been systematically studied to demonstrate their safety and effectiveness.
Biopsy.
Bone biopsy may be obtained during cement augmentation with a low risk and with adequate samples for pathologic diagnosis being obtained in more than 90% of cases. Routine biopsies have shown a small incidence (2%–10%) of undiagnosed malignancy, especially multiple myeloma and lymphoma, and if histomorphometry is performed, a high incidence of osteomalacia secondary to vitamin D deficiency.
In patients having known malignancy, the incidence of neoplasm findings on biopsy is greater than 50%. Currently, most authors do not recommend routine biopsy and use it only when there is clinical suspicion or in patients with a history of malignancy.
Cement Augmentation in Spinal Metastasis
Bone metastasis with resultant fractures occurs in 8% to 14% of cancer patients, most commonly in breast, prostate, lung, and thyroid cancers. In addition, multiple myeloma is associated with osteoporosis and spinal fracture in up to 24%. Pain from vertebral fractures can significantly reduce quality of life. The goal of management of pathologic spinal fractures is to prevent neurologic deterioration, palliate pain, and maintain function. Nonoperative treatments include pain management with opioids and other analgesics, bracing for oncology patients, radiotherapy, and chemotherapy or hormonal therapy. Bracing is poorly tolerated in oncology patients. Prevention of further fractures can be accomplished with intravenous administration of bisphosphonate medications such as zoledronate.
For painful metastatic fractures that do not respond to nonoperative management, cement augmentation can be considered. In an RCT, Berenson compared nonoperative treatment with kyphoplasty in patients with painful metastatic fractures. They found at 1 month significantly greater pain relief, overall function, and HRQOL in the kyphoplasty group. No difference in adverse events was present between the groups. Comparison of vertebroplasty with kyphoplasty for the management of metastatic lesions does not show any difference, although only cohort studies are available. Cement augmentation in metastatic lesions requires special consideration. Defects in the vertebral body wall increase the likelihood of cement extravasation. Embolism of tumor displaced during cement installation has been shown to occur in animal models, but there have been no reports in humans.
Surgical Intervention
As discussed in the previous section, cement augmentation (vertebroplasty or kyphoplasty) is warranted for palliative reasons but is not indicated for patients with neurologic deficits. Some fracture types and clinical situations may warrant more aggressive surgical intervention. Generally speaking, this is limited to situations when there is a neurologic deficit from retropulsed bone within the canal or progressive deformity that causes significant pain and functional disability. Any reconstructive surgery in osteoporotic patients is fraught with potential complications and therefore should be undertaken after careful patient selection and only after full informed consent.
In patients with neurologic deficits, there are several approaches to decompress the canal and provide stability to the compromised vertebral column. However, each patient should be approached individually, and there is no exact algorithm for the surgical management of these patients. The advantages of anterior surgery are the direct resection of the retropulsed bony fragment and subsequent decompression of the canal, as well as reconstruction of the weight-bearing anterior column. However, an anterior approach is not well tolerated in elderly patients who often have significant comorbidities. Furthermore, short-segment anterior fixation is often not adequate in osteoporotic patients. Therefore, a posterior approach is favored in these elderly patients with neurologic deficit from osteoporotic spine fractures.
Posterior decompression and stabilization with instrumentation is commonly used in fragility fractures with neurologic involvement ( Fig. 37-2 ). A circumferential decompression can be performed from a posterior approach. Transpedicular access to the posterior vertebral body allows the surgeon to adequately decompress the retropulsed fragment and avoids the morbidity associated with an anterior approach. The methods of posterior fixation and stabilization vary. Recently, several authors have recommended the use of short-segment fixation with vertebral body cement augmentation. The anterior column cement augmentation theoretically helps restore focal alignment and increases the stability of the construct, which in turn may decrease the risk of segmental collapse after surgery.
