Predictors of favorable quality of life outcome following kyphoplasty and vertebroplasty

OBJECTIVE

In 2009, 2 randomized controlled trials demonstrated no improvement in pain following vertebral augmentation compared with sham surgery. However, a recent randomized trial demonstrated significant pain relief in patients following vertebroplasty compared to controls treated with conservative medical management. This study is a retrospective review of prospectively collected patient-reported quality of life (QOL) outcomes. The authors hypothesized that vertebral augmentation procedures offer a QOL benefit, but that this benefit would be diminished in patients with a history of depression and/or in patients undergoing vertebral augmentation at more than 1 level.

METHODS

Multivariable linear regression was used to identify predictors of postoperative pain assessed using the Pain Disability Questionnaire (PDQ), Patient Health Questionnaire 9 (PHQ-9), and EQ-5D scores. Eleven candidate predictors were selected a priori: age, sex, smoking history, coronary artery disease, depression, diabetes, procedure location (thoracic, lumbar), BMI, prior spine surgery, procedure indication (metastases, osteoporosis/osteopenia, other), and number of levels (1, 2, 3, or more).

RESULTS

A total of 143 patients were included in the study. For each 10-year increase in age, postoperative PDQ scores decreased (improved) by 9.7 points (p < 0.001). Patients with osteoporosis/osteopenia had significantly higher (worse) postoperative PDQ scores (+17.97, p = 0.028) than patients with metastatic lesions. Male sex was associated with higher (worse) postoperative PHQ-9 scores (+2.48, p = 0.010). Compared to single-level augmentation, operations at 2 levels were associated with significantly higher PHQ-9 scores (+2.58, p = 0.017). Current smokers had significantly lower PHQ-9 scores (-1.98, p = 0.023) than never smokers. No predictors were associated with significantly different EQ-5D score.

CONCLUSIONS

Variables associated with worse postoperative PDQ scores included younger age and osteoporosis/osteopenia. Variables associated with decreased (better) postoperative PHQ-9 scores included female sex, single operative vertebral level, and positive smoking status (i.e., current smoker). These clinically relevant predictors may permit identification of patients who may benefit from vertebral augmentation.

Evaluation of predictive factors of vertebral compression fracture after conventional palliative radiotherapy for spinal metastasis from colorectal cancer

OBJECTIVE Delayed consequences of spinal radiotherapy (RT), including vertebral compression fracture (VCF), are critical complications. However, the predisposing factors that contribute to VCF after conventional RT are unclear. The aim of this study was to assess the incidence of VCF and to determine the predictors of VCF following conventional spinal RT specific to colorectal cancer (CRC). METHODS The authors retrospectively reviewed 237 spinal segments (147 metastatic and 90 nonmetastatic) in 53 patients with CRC who underwent RT with a median total dose of 30 Gy in 10 fractions between January 2007 and December 2014. The primary end point was the development of a VCF following RT, either de novo VCF or the progression of a baseline VCF. VCFs were assessed using the spinal instability neoplastic score (SINS) criteria. RESULTS Among all 237 spinal segments, 22 VCFs (9.3%) were observed following RT, including 13 de novo and 9 progressive fractures, and the median time to VCF was 4 months. All VCFs developed in metastatic spines. Among 147 metastatic spinal segments, 22 fractures were observed, with a 12-month cumulative incidence of VCF of 14.8%. Results of multivariable analysis indicated sex (p = 0.023) and SINS class II/III (p < 0.001) as risk factors related to development of a VCF in metastatic spinal segments. Among the SINS criteria, a lytic tumor and the presence of a baseline VCF were identified as predictors of VCF in metastatic spinal segments. CONCLUSIONS In osteolytic or mixed lesions that were predominant in spinal metastases of CRC, the incidence of VCF was not negligible, even in patients treated with conventional spinal RT. This was especially evident in patients with spinal metastases with a SINS score ≥ 7. Presence of a baseline VCF after spinal RT is a predictor of VCF development and should be observed carefully.

Reirradiation spine stereotactic body radiation therapy for spinal metastases: systematic review

OBJECTIVE Spinal metastases that recur after conventional palliative radiotherapy have historically been difficult to manage due to concerns of spinal cord toxicity in the retreatment setting. Spine stereotactic body radiation therapy (SBRT), also known as stereotactic radiosurgery, is emerging as an effective and safe means of delivering ablative doses to these recurrent tumors. The authors performed a systematic review of the literature to determine the clinical efficacy and safety of spine SBRT specific to previously irradiated spinal metastases. METHODS A systematic literature review was conducted, which was specific to SBRT to the spine, using MEDLINE, Embase, Cochrane Evidence-Based Medicine Database, National Guideline Clearinghouse, and CMA Infobase, with further bibliographic review of appropriate articles. Research questions included: 1) Is retreatment spine SBRT efficacious with respect to local control and symptom control? 2) Is retreatment spine SBRT safe? RESULTS The initial literature search retrieved 2263 articles. Of these articles, 160 were potentially relevant, 105 were selected for in-depth review, and 9 studies met all inclusion criteria for analysis. All studies were single-institution series, including 4 retrospective, 3 retrospective series of prospective databases, 1 prospective, and 1 Phase I/II prospective study (low- or very low-quality data). The results indicated that spine SBRT is effective, with a median 1-year local control rate of 76% (range 66%-90%). Improvement in patients' pain scores post-SBRT ranged from 65% to 81%. Treatment delivery was safe, with crude rates of vertebral body fracture of 12% (range 0%-22%) and radiation-induced myelopathy of 1.2%. CONCLUSIONS This systematic literature review suggests that SBRT to previously irradiated spinal metastases is safe and effective with respect to both local control and pain relief. Although the evidence is limited to low-quality data, SBRT can be a recommended treatment option for reirradiation.

Pathological characteristics of spine metastases treated with high-dose single-fraction stereotactic radiosurgery

OBJECTIVE Spine radiosurgery is increasingly being used to treat spinal metastases. As patients are living longer because of the increasing efficacy of systemic agents, appropriate follow-up and posttreatment management for these patients is critical. Tumor progression after spine radiosurgery is rare; however, vertebral compression fractures are recognized as a more common posttreatment effect. The use of radiographic imaging alone posttreatment may makeit difficult to distinguish tumor progression from postradiation changes such as fibrosis. This is the largest series from a prospective database in which the authors examine histopathology of samples obtained from patients who underwent surgical intervention for presumed tumor progression or mechanical pain secondary to compression fracture. The majority of patients had tumor ablation and resulting fibrosis rather than tumor progression. The aim of this study was to evaluate tumor histopathology and characteristics of patients who underwent pathological sampling because of radiographic tumor progression, fibrosis, or collapsed vertebrae after receiving high-dose single-fraction stereotactic radiosurgery. METHODS Between January 2005 and January 2014, a total of 582 patients were treated with linear accelerator-based single-fraction (18-24 Gy) stereotactic radiosurgery. The authors retrospectively identified 30 patients (5.1%) who underwent surgical intervention for 32 lesions with vertebral cement augmentation for either mechanical pain or instability secondary to vertebral compression fracture (n = 17) or instrumentation (n = 15) for radiographic tumor progression. Radiation and surgical treatment, histopathology, and long-term outcomes were reviewed. Survival and time to recurrence were calculated using the Kaplan-Meier method. RESULTS The mean age at the time of radiosurgery was 59 years (range 36-80 years). The initial pathological diagnoses were obtained for all patients and primarily included radioresistant tumor types, including renal cell carcinoma in 7 (22%), melanoma in 6 (19%), lung carcinoma in 4 (12%), and sarcoma in 3 (9%). The median time to surgical intervention was 24.7 months (range 1.6-50.8 months). The median follow-up and overall survival for all patients were 42.5 months and 41 months (overall survival range 7-86 months), respectively. The majority of assessed lesions showed no evidence of tumor on pathological review (25 of 32, 78%), while a minority of lesions revealed residual tumor (7 of 32, 22%). The median survival for patients after tumor recurrence was 5 months (range 2-70 months). CONCLUSIONS High-dose single-fraction radiosurgery is tumor ablative in the majority of instances. In a minority of cases, tumor persists and salvage treatments should be considered.

Anatomic and functional imaging in the diagnosis of spine metastases and response assessment after spine radiosurgery

Spine stereotactic radiosurgery (SSRS) has recently emerged as an increasingly effective treatment for spinal metastases. Studies performed over the past decade have examined the role of imaging in the diagnosis of metastases, as well as treatment response following SSRS. In this paper, the authors describe and review the utility of several imaging modalities in the diagnosis of spinal metastases and monitoring of their response to SSRS. Specifically, we review the role of CT, MRI, and positron emission tomography (PET) in their ability to differentiate between osteoblastic and osteolytic lesions, delineation of initial bony pathology, detection of treatment-related changes in bone density and vertebral compression fracture after SSRS, and tumor response to therapy. Validated consensus guidelines defining the imaging approach to SSRS are needed to standardize the diagnosis and treatment response assessment after SSRS. Future directions of spinal imaging, including advances in targeted tumor-specific molecular imaging markers demonstrate early promise for advancing the role of imaging in SSRS.

Re-irradiation stereotactic body radiotherapy for spinal metastases: a multi-institutional outcome analysis

OBJECTIVE This study is a multi-institutional pooled analysis specific to imaging-based local control of spinal metastases in patients previously treated with conventional external beam radiation therapy (cEBRT) and then treated with re-irradiation stereotactic body radiotherapy (SBRT) to the spine as salvage therapy, the largest such study to date. METHODS The authors reviewed cases involving 215 patients with 247 spinal target volumes treated at 7 institutions. Overall survival was calculated on a patient basis, while local control was calculated based on the spinal target volume treated, both using the Kaplan-Meier method. Local control was defined as imaging-based progression within the SBRT target volume. Equivalent dose in 2-Gy fractions (EQD2) was calculated for the cEBRT and SBRT course using an α/β of 10 for tumor and 2 for both spinal cord and cauda equina. RESULTS The median total dose/number of fractions of the initial cEBRT was 30 Gy/10. The median SBRT total dose and number of fractions were 18 Gy and 1, respectively. Sixty percent of spinal target volumes were treated with single-fraction SBRT (median, 16.6 Gy and EQD2/10 = 36.8 Gy), and 40% with multiple-fraction SBRT (median 24 Gy in 3 fractions, EQD2/10 = 36 Gy). The median time interval from cEBRT to re-irradiation SBRT was 13.5 months, and the median duration of patient follow-up was 8.1 months. Kaplan-Meier estimates of 6- and 12-month overall survival rates were 64% and 48%, respectively; 13% of patients suffered a local failure, and the 6- and 12-month local control rates were 93% and 83%, respectively. Multivariate analysis identified Karnofsky Performance Status (KPS) < 70 as a significant prognostic factor for worse overall survival, and single-fraction SBRT as a significant predictive factor for better local control. There were no cases of radiation myelopathy, and the vertebral compression fracture rate was 4.5%. CONCLUSIONS Re-irradiation spine SBRT is effective in yielding imaging-based local control with a clinically acceptable safety profile. A randomized trial would be required to determine the optimal fractionation.

Lordoplasty: midterm outcome of an alternative augmentation technique for vertebral fractures

OBJECTIVE Vertebroplasty and balloon kyphoplasty are effective treatment options for osteoporotic vertebral compression fractures but are limited in correction of kyphotic deformity. Lordoplasty has been reported as an alternative, cost-effective, minimally invasive, percutaneous cement augmentation technique with good restoration of vertebral body height and alignment. The authors report on its clinical and radiological midterm results. METHODS A retrospective review was conducted of patients treated with lordoplasty from 2002 to 2014. Inclusion criteria were clinical and radiological follow-up evaluations longer than 24 months. Radiographs were accessed regarding initial correction and progressive loss of reduction. Complications and reoperations were recorded. Actual pain level, pain relief immediately after surgery, autonomy, and subjective impression of improvement of posture were assessed by questionnaire. RESULTS Sixty-five patients (46 women, 19 men, age range 38.9-86.2 years old) were treated with lordoplasty for 69 vertebral compression and insufficiency fractures. A significant correction of the vertebral kyphotic angle (mean 13°) and segmental kyphotic angle (mean 11°) over a mean follow-up of 33 months (range 24-108 months) was achieved (p < 0.001). On average, pain was relieved to 90% of the initial pain level. In 24% of the 65 patients a second spinal intervention was necessary: 16 distant (24.6%) and 7 adjacent (10.8%) new osteoporotic fractures, 4 instrumented stabilizations (6.2%), 1 new adjacent traumatic fracture (1.5%), and 1 distant microsurgical decompression (1.5%). Cement leakage occurred in 10.4% but was only symptomatic in 1 case. CONCLUSIONS Lordoplasty appeared safe and effective in midterm pain alleviation and restoration of kyphotic deformity in osteoporotic compression and insufficiency fractures. The outcomes of lordoplasty are consistent with other augmentation techniques.

Long-term follow-up study of osteoporotic vertebral compression fracture treated using balloon kyphoplasty and vertebroplasty

OBJECT

Long-term follow-up study is required for verifying whether the clinical outcomes of kyphoplasty and vertebroplasty are altered. The authors' findings showed only subtle differences between these operations within a 5-year period. However, they still suggest the use of vertebroplasty over kyphoplasty in view of the treatment costs. In their previous study, the authors performed a short-term prospective comparison between vertebroplasty and kyphoplasty. Vertebroplasty was recommended instead of kyphoplasty for the treatment of vertebral compression fractures (VCFs) because of the subtle differences between this procedure and kyphoplasty and the treatment costs. To determine whether these clinical outcomes persist in the long term, they continued to observe the patients from their short-term study over a longer-term period. METHODS :One hundred cases of VCF were assigned randomly to either the kyphoplasty or the vertebroplasty group. In cement augmentation, the authors used polymethylmethacrylate as bone filler. Pain was assessed by using a visual analog scale (VAS). For each patient, vertebral body height and wedge angle were measured from reconstructed CT images.

RESULTS

The duration of the follow-up period was 5 years. Vertebral body height, kyphotic wedge angle, and VAS score were not evidently altered. Eight patients in the kyphoplasty group had an adjacent fracture after the procedure, whereas 7 patients in the vertebroplasty group had an adjacent fracture after the procedure. These adjacent fractures occurred within 1 year of surgery in both treatment groups except in 1 kyphoplasty-treated patient in whom the adjacent fracture was noted 16 months after treatment. Three patients in the vertebroplasty group had a nonadjacent fracture, and 4 patients in the kyphoplasty group had a nonadjacent fracture. The link between angular correction and the occurrence of adjacent fracture was statistically significant in the vertebroplasty group.

CONCLUSIONS

Excessive angular correction is a critical concern in the risk of adjacent fracture after vertebroplasty. Given the subtle differences between vertebroplasty and kyphoplasty observed over the course of 5 years, vertebroplasty remains the preferred option in view of the costs.

Effects of vertebroplasty on endplate subsidence in elderly female spines

OBJECT

The aim in this study was to quantify the effects of vertebroplasty on endplate subsidence in treated and adjacent vertebrae and their relationship to endplate thickness and underlying trabecular bone in elderly female spines.

METHODS

Vertebral compression fractures were created in female cadaveric (age range 51-88 years) thoracolumbar spine segments. Specimens were placed into either the control or vertebroplasty group (n = 9/group) such that bone mineral density, trabecular microarchitecture, and age were statistically similar between groups. For the vertebroplasty group, polymethylmethacrylate bone cement was injected into the fractured vertebral body under fluoroscopy. Cyclic compression (685-1370 N sinusoid) was performed on all spine segments for 115,000 cycles. Micro-CT scans were obtained before and after cyclic loading to quantify endplate subsidence. Maximum subsidence was compared between groups in the caudal endplate of the superior adjacent vertebra (SVcau); cranial (TVcra) and caudal (TVcau) endplates of the treated vertebra; and the cranial endplate of the inferior adjacent vertebra (IVcra). In addition, micro-CT images were used to quantify average endplate thickness and trabecular bone volume fraction. These parameters were then correlated with maximum endplate subsidence for each endplate.

RESULTS

The maximum subsidence in SVcau endplate for the vertebroplasty group (0.34 ± 0.58 mm) was significantly (p < 0.05) greater than for the control group (-0.13 ± 0.27 mm). Maximum subsidence in the TVcra, TVcau, and IVcra endplates were greater in the vertebroplasty group, but these differences were not significant (p > 0.16). Increased subsidence in the vertebroplasty group manifested locally in the anterior region of the SVcau endplate and in the posterior region of the TVcra and TVcau endplates (p < 0.10). Increased subsidence was observed in thinner endplates with lower trabecular bone volume fraction for both vertebroplasty and control groups (R(2) correlation up to 62%). In the SVcau endplate specifically, these 2 covariates aided in understanding subsidence differences between vertebroplasty and control groups.

CONCLUSIONS

Bone cement injected during vertebroplasty alters local biomechanics in elderly female spines, resulting in increased endplate disruption in treated and superior adjacent vertebrae. More specifically, bone cement increases subsidence in the posterior regions of the treated endplates and the anterior region of the superior caudal endplate. This increased subsidence may be the initial mechanism leading to subsequent compression fractures after vertebroplasty, particularly in vertebrae superior to the treated level.

Spine stereotactic body radiotherapy for renal cell cancer spinal metastases: analysis of outcomes and risk of vertebral compression fracture

OBJECT

The aim of this study was to evaluate local control (LC) and the risk of vertebral compression fracture (VCF) after stereotactic body radiotherapy (SBRT) in patients with renal cell cancer spinal metastases.

METHODS

Prospectively collected data on 71 spinal segments treated with SBRT in 37 patients were reviewed. The median follow-up was 12.3 months (range 1.2-55.4 months). The LC rate was assessed based on each spinal segment treated and overall survival (OS) according to each patient treated. Sixty of 71 segments (85%) were radiation naive, 11 of 71 (15%) were previously irradiated, and 10 of 71 (14%) were treated with postoperative SBRT. The median SBRT total dose and number of fractions were 24 Gy and 2, respectively. The VCF analysis also included evaluation of the Spinal Instability Neoplastic Score criteria.

RESULTS

The 1-year OS and LC rates were 64% and 83%, respectively. Multivariate analysis identified oligometastatic disease (13 of 37 patients) as a positive prognostic factor (p = 0.018) for OS. Of 61 non-postoperative spinal segments treated, 10 (16%) developed VCFs; 3 of 10 were de novo VCFs and 7 of 10 occurred as progression of an existing VCF. The 1-year VCF-free probability rate was 82%. Multivariate analysis identified single-fraction SBRT and baseline VCF as significant predictors of SBRT-induced VCF (p = 0.028 and p = 0.012, respectively).

CONCLUSIONS

Spine SBRT yields high rates of local tumor control in patients with renal cell cancer. Baseline VCF and 18-24 Gy delivered in a single fraction were predictive of further collapse. Patients with oligometastatic disease may benefit most from such aggressive local therapy, given the prolonged survival observed.

Utility of routine biopsy at vertebroplasty in the management of vertebral compression fractures: a tertiary center experience

OBJECT

The authors assess the utility of routine biopsy at vertebroplasty for vertebral compression fracture (VCF) as a tool in the early detection of malignancy in presumed benign VCF.

METHODS

A prospective observational study was conducted on a cohort of consecutive patients undergoing vertebroplasty over a 5-year period between April 2006 and March 2011 at the Royal London Hospital. Polymethylmethacrylate cement injection was used in every procedure. Intraoperative vertebral body biopsy was performed routinely at every level of VCF. Pain visual analog scale (VAS) scores, Oswestry Disability Index (ODI) scores, analgesic usage, and complications were recorded preoperatively and at 1 day, 1 week, 1 month, 6 months, and 1 year postoperatively.

RESULTS

A total of 202 levels were augmented in 147 patients. The most common levels augmented were T-12 (17%), L-1 (18%), and L-4 (10%). Analysis of 184 routine vertebral biopsies in 135 patients revealed that in 86 patients with presumed osteoporosis and no prior cancer diagnosis, 4 (4.7%) had a malignant VCF. In 20 known cancer patients presumed to be in remission, 2 (10%) had a malignant VCF. Routine vertebral biopsy returned an overall cancer diagnosis rate of 5.5% (6 of 109) when combining the 2 groups (patients with no prior history of cancer or cancer thought to be in remission). In these 6 patients, history, examination, laboratory tests, and preprocedure imaging all failed to suggest malignancy diagnosed at routine biopsy. Significant reductions in pain VAS and ODI scores were evident at Day 1 and were sustained at up to 1 year postoperatively (p < 0.001). They were not dependent on the level of fracture (T3-10, T11-L2, or L3-S1) (p > 0.05), number of levels treated (single level, 2 levels, or > 2 levels) (p > 0.05), or etiology of VCF (p > 0.05). The complication rate was 6% (9 of 147). There were 5 deaths, none of which were directly related to surgery.

CONCLUSIONS

Routine vertebral biopsy performed at vertebroplasty may demonstrate cancer-related VCFs in unsuspected patients with no previous cancer diagnosis or active malignancy in patients previously thought to be in remission. This early diagnosis of cancer or relapsed disease will play an important role in expediting patients' subsequent cancer management. In cases of multiple-level VCF, the authors advocate biopsy at each level to maximize the diagnostic yield from the specimens and to avoid missing a malignancy at a single level.

Tumor extravasation following a cement augmentation procedure for vertebral compression fracture in metastatic spinal disease

Balloon kyphoplasty (BKP) has been proven to be safe and effective in the management of pathological vertebral compression fracture (VCF) due to metastatic spinal disease. The most common serious complications related to BKP include cement extravasation and new fractures at adjacent levels. Although the potential for "tumor extravasation" has been discussed as a potential iatrogenic complication, it has yet to be confirmed. The authors report on 2 cases of tumor extravasation following BKP, which they base on an observed unusual rapid tumor spread pattern into the adjacent tissues. They postulate that by increasing the vertebral body internal pressure and disrupting the tissues during balloon inflation and cement application, a soft-tissue tumor can be forced beyond the vertebral bony boundaries through pathological cortical defects. This phenomenon can manifest radiologically as subligamentous spread and/or extension into venous sinusoids, resulting in epidural venous plexus involvement, with subsequent tumor migration into the adjacent vertebral segments. Accordingly, the authors advise caution in using BKP when significant epidural tumor is present. The complication they encountered has caused them to modify their preference such that they now first use radiosurgery and subsequently BKP to ensure the target is appropriately treated, and they are currently developing possible modifications of procedural technique to reduce the risk.

Compression fracture in the middle of a chronic instrumented fusion that developed into pseudarthrosis after balloon kyphoplasty

There are only 2 documented cases of vertebral compression fractures occurring within a solid lumbar fusion mass: one within the fusion mass after hardware removal and the other within the levels of the existing instrumentation 1 year postoperatively. The authors report a case of fracture occurring in a chronic (> 30 years) solid instrumented fusion mass in a patient who underwent kyphoplasty. The pain did not improve after the kyphoplasty procedure, and the patient developed a posterior cleft in the fusion mass postoperatively. The patient, a 46-year-old woman, had undergone a T4-L4 instrumented fusion with placement of a Harrington rod when she was 12 years old. Adjacent-segment breakdown developed, and her fusion was extended to the pelvis, with pedicle screws placed up to L-3 to capture the existing fusion mass. Almost 2 years after fusion extension, she fell down the stairs and suffered an L-2 compression fracture, which is when kyphoplasty was performed without pain relief, and she then developed a cleft in the posterior fusion mass that was previously intact. She refused further surgical options. This case report is meant to alert surgeons of this possibility and allow them to consider the rare occurrence of fracture within the fusion mass when planning extension of chronic spinal fusions.