23 Number of Levels Appropriately Treated with Vertebral Augmentation

10.1055/b-0040-175472

23 Number of Levels Appropriately Treated with Vertebral Augmentation

Pyung-Bok Lee and Yong-Chul Kim

Summary

Vertebral augmentation, such as vertebroplasty and kyphoplasty has been introduced as effective treatment options for vertebral compression fracture. Unfortunately, there are many multiple level fractures in both osteoporotic and metastatic compression fractures. There are also still some questions about the maximum number of levels that should undergo vertebral augmentation. Current guidelines indicate that complications of vertebral augmentation may be amplified when more than three vertebral levels are treated concurrently but this has not been reflected in numerous clinical trials, and some researchers have found that complications such as anemia and new compression fracture did not increase with multiple levels of augmentation. They also suggested that treating all the fractures at once might decrease the patients’ morbidity. In conclusion although the number of compression fracture levels to treat with vertebral augmentation should be based on a meticulous analysis of each individual’s circumstances and many levels can be treated in an attempt to decrease patient morbidity, a generally agreed upon maximum number of levels is three per augmentation session.

23.1 Introduction

Vertebral compression fractures (VCFs) related to osteoporosis are very common in the elderly. ¹ ^, ² In recent years, minimally invasive percutaneous cement augmentation techniques, such as vertebroplasty and kyphoplasty, have been introduced as effective treatment options. ² ^– ⁸ These techniques have demonstrated excellent clinical outcomes, restoring the collapsed body height and reducing pain both in the short- and long-term. ² ^, ⁴ However, one of the difficulties of vertebral augmentation techniques is the treatment of multiple fractures. ³ In both osteoporosis and metastasis, it is common to find multiple fractures, and about 20 to 47% of the patients with a previously diagnosed compression fracture develop new ones. ⁵ ^– ⁷ ^, ⁹ Consequently, some authors suggest the prophylactic augmentation of decalcified vertebrae as a method to prevent subsequent fractures that may increase overall mortality. ⁸ ^, ¹⁰ ^, ¹¹ Additionally, almost 4% of the fractures are a consequence of neoplastic disease, which can be sampled during the vertebral augmentation procedure via vertebral biopsy. ¹² ^– ¹⁴ Pathological fractures due to malignant tumors of the vertebrae also have been found to be adequately treated with vertebroplasty, which can produce sufficient pain control and a better quality of life. ¹⁵ ^, ¹⁶

23.2 Neoplastic Vertebral Fractures

From the retrospective analysis of cancer patients, most compression fractures occurred at the thoracolumbar junction, with T11, T12, L1, and L2 accounting for 69.4% of all treated levels. The distribution of compression fractures by type of cancer show that 88.2% of documented metastatic compression fractures and 71% of all compression fractures had multiple myeloma, breast cancer, or lung cancer. Unlike osteoporotic compression fractures, in cancer patients there was a fairly even distribution of all compression fractures and metastatic compression fractures between the two sexes. ¹⁷

23.3 Risk Factors for Vertebral Compression Fractures

In a study with postmenopausal Japanese-American women, Ross et al ¹⁸ found a fivefold increase in the risk of a new vertebral fracture when a single vertebral fracture was present at baseline. This risk increased to 12-fold when there were two or more fractures at baseline. Lindsay et al ¹⁹ in a multicenter study involving 2,725 postmenopausal women with a mean age of 74 years found a cumulative incidence of 6.6% new fractures in the first year. Overall, 19.2% of the women with a confirmed incidental fracture had a second fracture within one year; 11.5% of the women with one previous fracture sustained a second fracture, whereas 24% of the women with two or more prevalent fractures at baseline had a new fracture within a year following the first observed fracture (▶Fig. 23.1).

**Fig. 23.1 (a, b)** Incidence of vertebral fracture by number of baseline vertebral fractures. New compression fractures happened more in previous multilevel fractures at 1-year follow-up.

Bed rest or inactivity as a result of pain from VCFs accelerates bone loss, which may increase the risk of additional fractures. Increased kyphosis from previous fractures also predisposes the patient to recurrent fractures. Black et al ²⁰ found that prevalent vertebral deformities from previous fractures were associated with a fivefold increase in the risk of new fractures. Moreover, the risk was higher as the number of preexisting fractures and the severity of the deformity increased. Additionally, the presence of multiple and severe VCFs was found to be a specific risk factor for sustaining femoral neck fractures. ²¹

23.4 Number of Levels to Treat with Vertebral Augmentation

Although there is extensive information regarding the increased incidence of new vertebral fractures after an initial one, there is no firm consensus on how many levels should be treated with vertebral augmentation. Some authors have suggested that the augmentation of one vertebra can increase the probability of new fractures in the adjacent ones; thus, prophylactic augmentation of decalcified vertebrae should be considered. ⁸ ^, ¹⁰ Moreover, there are cases with multiple compression fractures, and as many as 16 levels of augmentations in a single patient have been reported (▶Fig. 23.2). ²² However, there are still some questions about the number of levels that should undergo vertebral augmentation. Should all the compressed levels be treated with augmentation? If not, which level(s) should be chosen to perform the vertebral augmentation? Finally, in the case of a single-level compression, is it better to perform an additional augmentation to the adjacent decalcified vertebrae?

**Fig. 23.2 (a, b)** Multilevel vertebral augmentation. As many as 16 levels were treated with vertebral augmentation.

23.5 Diagnosis of Painful Vertebral Compression Fractures

First of all, attention must be centered in the accurate diagnosis of the compressed fracture level that is contributing to the recent pain escalation. Lyritis et al ²³ attempted to determine the clinical outcomes based on the initial radiographic appearance of the vertebral fractures. In their study, patients with an obvious wedge fracture had severe, sharp pain, which gradually decreased within 4 to 8 weeks (▶Fig. 23.3). Conversely, patients with minimal superior end-plate discontinuity tended to have a gradual progression to complete collapse of the vertebral body and had dull, less severe, and recurrent pain. Conclusively, before considering a vertebral augmentation, a thoughtful, cautious, and accurate physical examination must be performed. In the patients with a possible VCF, the key physical examination signs are the presence of severe concordant pain with palpation or percussion on the suspected fractured spinous process, deep tenderness of paravertebral muscle pain, and facet joint compression. Langdon et al ²⁴ found that closed-fist percussion had sensitivity and specificity of 87.5 and 90%, respectively, for detecting VCFs. These authors also described a supine sign test that was 81.25% sensitive and 93.33% specific for detecting VCFs when the patient was unable to lie supine without prominent discomfort. Finally, when both physical and radiographic image examinations are positive for vertebral fracture, performing vertebral augmentation at one or two levels is often enough to successfully control the acute pain.

**Fig. 23.3** Wedge shape compression fracture. Wedge fractures can have severe, sharp pain.

In cases with multiple compression fractures, Wang and Fahim ¹⁶ concluded that the patients treated with vertebral augmentation at once had better pain control than the ones treated in two different sessions, the first to repair a portion of the fractured vertebral bodies and a second to repair the remaining fractures. The patients with two procedures remained bed bound due to the persistent pain, had an increased hospice stay, and suffered additional morbidities. Additionally, there may be hidden neoplastic lesions or fractures despite the interrogation by experienced physical examinations and conventional radiography. Bone scanning plays a role in identifying osteoporotic fractures in patients who have negative findings on plain radiographs and in identifying additional fractures at other levels. Magnetic resonance imaging (MRI) of the spine is one of the most useful tests for determining fracture age, ruling out a malignant tumor, and selecting the appropriate treatment. Park et al ²⁵ suggested that MRI with STIR sequencing exhibited a multitude of benefits in the exact identification of both acute and hidden lesions. In this study, MRI with STIR sequencing revealed that 23% of the single fracture group and 65% of the multiple fracture group had additional acute lesions that were not identified on a CT scan (▶Fig. 23.4). Therefore, as suggested in previous studies, the determination of the appropriate level is critical to achieving better clinical outcomes after vertebral augmentation. Additionally, 31 of their cases had multiple hidden lesions. They concluded that if the hidden lessons are not treated and the cement augmentation is performed at a single level only, undesirable clinical outcomes may arise as a consequence of the missed and untreated lesion(s) which may further deteriorate after the initial procedure. In neoplastic lesions bone SPECT may be comparable for differentiating malignant from benign VCFs, especially, in the case of VCFs with a complete replacement of the normal fatty marrow. This means it is possible to use bone single-photon emission tomography (SPECT) as a substitute for MRI for differentiating malignant from benign VCFs. ²⁶