Spinal instability and deformity due to neoplastic conditions

Surgical Management of Extradural Tumors at the Craniovertebral Junction - Insights from a Tertiary Care Center

BACKGROUND

Craniovertebral junction (CVJ) tumors are challenging due to their unique anatomical location. This study aimed to evaluate the complexities in dealing with such precarious CVJ extradural lesions over the decade.

METHODS

Twenty-seven patients of extradural CVJ tumors operated between 2009 and 2018 were included. The demographic details, neurological status, surgical approach, extent of resection, type of fixation, complications, and outcome at final follow-up were recorded for each patient.

RESULTS

The mean age of the patients was 39.5 ± 20 years. Most (17/27) of the patients had involvement of a single level. Clivus was the most common (9/17) involved region followed by atlas (7/17) vertebrae. Majority of the patients (13/27) were operated through the posterior-only approach. About 15 patients (55.5%) had instability or extensive lesions that necessitated posterior fixation. None of the patients underwent anterior fixation. Gross and near total excision were achieved in 10 patients (37%) and 3 patients (11%) respectively while 14 patients underwent subtotal excision of tumor. On histopathological analysis, clival chordoma (8/27) was found to be the most common pathology followed by giant cell tumor (6/27), plasmacytoma (4/27), and multiple myeloma (2/27). Most patients (13 out of 27) had the same neurological status after the surgery. Six patients (22%) improved post-operatively with decreased weakness and spasticity. Thirteen (48%) patients underwent adjuvant radiotherapy.

CONCLUSIONS

This retrospective study provides valuable insights into managing extradural CVJ tumors and highlights the importance of individualized approaches for optimal outcome.

Correlation Between the Spinal Instability Neoplastic Score (SINS) and Patient Reported Outcomes

STUDY DESIGN

International multicenter prospective observational cohort study on patients undergoing radiation +/- surgical intervention for the treatment of symptomatic spinal metastases.

OBJECTIVES

To investigate the association between the total Spinal Instability Neoplastic Score (SINS), individual SINS components and PROs.

METHODS

Data regarding patient demographics, diagnostics, treatment, and PROs (SF-36, SOSGOQ, EQ-5D) was collected at baseline, 6 weeks, and 12 weeks post-treatment. The SINS was assessed using routine diagnostic imaging. The association between SINS, PRO at baseline and change in PROs was examined with the Spearmans rank test.

RESULTS

A total of 307 patients, including 174 patients who underwent surgery+/- radiotherapy and 133 patients who underwent radiotherapy were eligible for analyses. In the surgery+/- radiotherapy group, 18 (10.3%) patients with SINS score between 0-6, 118 (67.8%) with a SINS between 7-12 and 38 (21.8%) with a SINS between 13-18, as compared to 55 (41.4%) SINS 0-6, 71(53.4%) SINS 7-12 and 7 (5.2%) SINS 13-18 in the radiotherapy alone group. At baseline, the total SINS and the presence of mechanical pain was significantly associated with the SOSGOQ pain domain (r = -0.519, P < 0.001) and the NRS pain score (r = 0.445, P < 0.001) for all patients. The presence of mechanical pain demonstrated to be moderately associated with a positive change in PROs at 12 weeks post-treatment.

CONCLUSION

Spinal instability, as defined by the SINS, was significantly correlated with PROs at baseline and change in PROs post-treatment. Mechanical pain, as a single SINS component, showed the highest correlations with PROs.

Craniovertebral Junction Instability after Oncological Resection: A Narrative Review

The craniovertebral junction (CVJ) is a complex transition area between the skull and cervical spine. Pathologies such as chordoma, chondrosarcoma and aneurysmal bone cysts may be encountered in this anatomical area and may predispose individuals to joint instability. An adequate clinical and radiological assessment is mandatory to predict any postoperative instability and the need for fixation. There is no common consensus on the need for, timing and setting of craniovertebral fixation techniques after a craniovertebral oncological surgery. The aim of the present review is to summarize the anatomy, biomechanics and pathology of the craniovertebral junction and to describe the available surgical approaches to and considerations of joint instability after craniovertebral tumor resections. Although a one-size-fits-all approach cannot encompass the extremely challenging pathologies encountered in the CVJ area, including the possible mechanical instability that is a consequence of oncological resections, the optimal surgical strategy (anterior vs posterior vs posterolateral) tailored to the patient's needs can be assessed preoperatively in many instances. Preserving the intrinsic and extrinsic ligaments, principally the transverse ligament, and the bony structures, namely the C1 anterior arch and occipital condyle, ensures spinal stability in most of the cases. Conversely, in situations that require the removal of those structures, or in cases where they are disrupted by the tumor, a thorough clinical and radiological assessment is needed to timely detect any instability and to plan a surgical stabilization procedure. We hope that this review will help shed light on the current evidence and pave the way for future studies on this topic.

Cervical Spine Reconstruction with Chest Tube Technique After Metastasis Resection: A Single-Center Experience

BACKGROUND

The silastic tube technique, in which a chest tube is placed into the vertebral body defect and impregnated with polymethyl methacrylate, showed good results in patients with lumbar and thoracic neoplastic diseases. There has been only 1 study about the effectiveness and safety of this technique in patients with cervical metastases. We aimed to report our experience in using this technique to reconstruct the spine after corpectomy for cervical metastasis.

METHODS

All patients with cervical spinal metastasis who underwent surgical treatment using a chest tube impregnated with polymethyl methacrylate in conjunction with anterior cervical plate stabilization were retrospectively recruited. Demographics, tumor histology, revised Tokuhashi score, preoperative and postoperative American Spinal Injury Association score, preoperative and postoperative ambulatory status, perioperative complications, and survival time were collected.

RESULTS

This study included 16 patients. The most common primary tumor site was the lung (6 patients; 37.5%). The mean (SD) survival time was 408 (401) days (range, 1-2797 days), and the median survival time was 72 days (95% confidence interval 28-116 days). Four patients (25%) died within 30 postoperative days. There was no surgical site infection or instrument failure after the surgery. Five patients (31.2%) lived >180 days, and 3 patients (18.8%) lived >360 days. One patient (6.2%) was still alive at the end of the study.

CONCLUSIONS

The silastic tube technique in conjunction with anterior cervical plate stabilization might be safe, effective, and cost-effective for patients with cervical spine metastasis.

Improved estimates of strength and stiffness in pathologic vertebrae with bone metastases using CT-derived bone density compared with radiographic bone lesion quality classification

OBJECTIVE

The aim of this study was to compare the ability of 1) CT-derived bone lesion quality (classification of vertebral bone metastases [BM]) and 2) computed CT-measured volumetric bone mineral density (vBMD) for evaluating the strength and stiffness of cadaver vertebrae from donors with metastatic spinal disease.

METHODS

Forty-five thoracic and lumbar vertebrae were obtained from cadaver spines of 11 donors with breast, esophageal, kidney, lung, or prostate cancer. Each vertebra was imaged using microCT (21.4 μm), vBMD, and bone volume to total volume were computed, and compressive strength and stiffness experimentally measured. The microCT images were reconstructed at 1-mm voxel size to simulate axial and sagittal clinical CT images. Five expert clinicians blindly classified the images according to bone lesion quality (osteolytic, osteoblastic, mixed, or healthy). Fleiss' kappa test was used to test agreement among 5 clinical raters for classifying bone lesion quality. Kruskal-Wallis ANOVA was used to test the difference in vertebral strength and stiffness based on bone lesion quality. Multivariable regression analysis was used to test the independent contribution of bone lesion quality, computed vBMD, age, gender, and race for predicting vertebral strength and stiffness.

RESULTS

A low interrater agreement was found for bone lesion quality (κ = 0.19). Although the osteoblastic vertebrae showed significantly higher strength than osteolytic vertebrae (p = 0.0148), the multivariable analysis showed that bone lesion quality explained 19% of the variability in vertebral strength and 13% in vertebral stiffness. The computed vBMD explained 75% of vertebral strength (p < 0.0001) and 48% of stiffness (p < 0.0001) variability. The type of BM affected vBMD-based estimates of vertebral strength, explaining 75% of strength variability in osteoblastic vertebrae (R2 = 0.75, p < 0.0001) but only 41% in vertebrae with mixed bone metastasis (R2 = 0.41, p = 0.0168), and 39% in osteolytic vertebrae (R2 = 0.39, p = 0.0381). For vertebral stiffness, vBMD was only associated with that of osteoblastic vertebrae (R2 = 0.44, p = 0.0024). Age and race inconsistently affected the model's strength and stiffness predictions.

CONCLUSIONS

Pathologic vertebral fracture occurs when the metastatic lesion degrades vertebral strength, rendering it unable to carry daily loads. This study demonstrated the limitation of qualitative clinical classification of bone lesion quality for predicting pathologic vertebral strength and stiffness. Computed CT-derived vBMD more reliably estimated vertebral strength and stiffness. Replacing the qualitative clinical classification with computed vBMD estimates may improve the prediction of vertebral fracture risk.

Low Implant Failure Rate of Percutaneous Fixation for Spinal Metastases: A Multicenter Retrospective Study

OBJECTIVE

To evaluate incidence and types of implant failure observed in a series of patients with spinal metastases (SM) treated with minimally invasive stabilization surgery without fusion.

METHODS

In this multicenter, retrospective, observational study, we reviewed the files of patients >18 years old who underwent surgery for SM using percutaneous spinal stabilization without fusion with a minimum 3-month follow-up. The following variables were included: demographics, clinical findings, prior radiation history, SM location, epidural spinal cord compression scale, Spinal Instability Neoplastic Scale, neurological examination, and surgery-related data. Primary outcome measure was implant failure rate, as observed in patients' last computed tomography scan. Multivariable analysis was performed to identify baseline factors and factors associated with implant failure.

RESULTS

Analysis included 72 patients. Mean age of patients was 62 years, 39 patients were men, and 75% of patients had an intermediate Spinal Instability Neoplastic Scale score. Tumor separation surgery was performed in 48.6% of patients. Short instrumentation was indicated in 54.2% of patients. Three patients (4.2%) experienced implant failure (2 screw loosening, 1 screw cut-out); none of them required revision surgery. In 73.6% of cases, survival was >6 months. No significant predictors of failure were identified in the multivariate analysis.

CONCLUSIONS

A low implant failure rate was observed over the short and medium term, even when short instrumentations without fusion were performed. These findings suggest that minimally invasive stabilization surgery without fusion may be an effective and safe way to treat complicated SM.

A prospective randomized cohort study on 3D-printed artificial vertebral body in single-level anterior cervical corpectomy for cervical spondylotic myelopathy

Background

This was a prospective randomized cohort study aiming at examining the safety and efficacy of artificial vertebral body (AVB) fabricated by electron beam melting (EBM) in comparison to conventional titanium mesh cage (TMC) used in single-level anterior cervical corpectomy and fusion (SL-ACCF).

Methods

Forty patients with cervical spondylotic myelopathy (CSM) underwent SL-ACCF using either the EBM-AVB or the TMC. Patients were evaluated for their demographics, radiological characteristics, neurologic function [using the Japanese Orthopaedic Association (JOA) scale], and health-related quality-of-life (HRQoL) aspects [using the Short Form 36 (SF-36)] before and after the surgery and comparison was made between the two groups both at baseline and the last follow-up. The Student t-text, paired-sample t-text, and Fisher's exact test were used when appropriate to detect any statistical significance at the level of α=0.05.

Results

Post-operative recovery was uneventful for all patients and no revision surgery was required. There were no significant differences between the EBM-AVB group and the TMC group at baseline. Patients in both groups demonstrated significant improvement in cervical alignment, JOA score, and SF-36 score after the surgery. Six months post-operatively, patients in the EBM-AVB group were found to have significantly less loss of fusion height and lower incidence for severe implant subsidence compared with the TMC group. Patients in the two groups were comparable at the last follow-up regarding their rate of fusion, cervical alignment, JOA recovery rate, SF-36 score, and by Odom's criteria.

Conclusions

For CSM patients undergoing SL-ACCF, the EBM-AVB group demonstrated comparable outcomes regarding patient cervical alignment, neurologic function, and HRQoL in comparison with the TMC group. Furthermore, the use of EBM-AVB was associated with decreased loss of the height of the fusion mass and a lower rate for severe implant subsidence.

Symptomatic Construct Failure after Metastatic Spine Tumor Surgery

Study Design

Retrospective cohort study.

Purpose

To evaluate the incidence and presentation of symptomatic failures (SFs) after metastatic spine tumor surgery (MSTS). To identify the associated risk factors. To categorize SFs based on the management in these patients.

Overview of Literature

Few studies have reported on the incidence (1.9%–16%) and risk factors of SF after MSTS. It is unclear whether all SFs, occurring in MSTS-patients, result in revision surgery.

Methods

We conducted a retrospective analysis on 288 patients (246 for final analysis) who underwent MSTS between 2005–2015. Data collected were demographics and peri/postoperative clinical and radiological features. Early and late radiological SF were defined as presentation before and after 3 months from index surgery, respectively. Univariate and multivariate models of competing risk regression analysis were designed to determine the risk factors for SF with death as a competing event.

Results

We observed 14 SFs (5.7%) in 246 patients; 10 (4.1%) underwent revision surgery. Median survival was 13.4 months. The mean age was 58.8 years (range, 21–87 years); 48.4% were women. The median time to failure was 5 months (range, 1–60 months). Patients with SF were categorized into three groups: (1) SF when the primary implant was revised (n=5, 35.7%); (2) peri-construct progression of disease requiring extension (n=5, 35.7%); and (3) SFs that did not warrant revision (n=4, 28.5%). Four patients (28.5%) presented with early failure. SF commonly occurred at the implant-bone interface (9/14) and all patients had a spinal instability neoplastic score (SINS) >7. Thirteen patients (92.8%) who developed failure had fixation spanning junctional regions. Multivariate competing risk regression showed that preoperative Eastern Cooperative Oncology Group score was a significant risk factor for implant failure (adjusted sub-hazard ratio, 7.0; 95% confidence interval, 1.63–30.07; p<0.0009).

Conclusions

The incidence of SF (5.7%) was low in patients undergoing MSTS although these patients did not undergo spinal fusion. Preoperative ambulators involved a 7 times higher risk of failure than non-ambulators. Preoperative SINS >7 and fixations spanning junctional regions were associated with SF. Majority of construct failures occurred at the implant-bone interface.

The Role of Stabilization-Free Microsurgical Decompression in the Surgical Treatment of Spinal Metastases

OBJECTIVE

Symptomatic spine metastases are found in about 10% of patients with cancer. As the long-term survival of patients with carcinoma rises, the number of patients with symptomatic spine metastases is also increasing. In our tertiary referral center, patients usually present rapidly progressive neurologic disorders, which require an urgent treatment decision. Treatment options include extensive 360° stabilizations. These complex interventions are not always readily available. We examined the extent to which the patient population benefited from decompressive surgery without stabilization. We hypothesize that patients benefit from merely dorsal decompression, which preserves stability when they experience symptomatic spine metastases.

METHODS

We performed a retrospective analysis of electronic patient data from 19 patients, who were treated for symptomatic spine metastases by hemilaminectomy between 2009 and 2017. We evaluated the preoperative and postoperative neurologic functions using the American Spinal Injury Association (ASIA) Impairment Scale. A comparative literature analysis was carried out to assess the Spinal Neoplastic Instability Score, Tokuhashi score, and Tomita score.

RESULTS

Nine participants had prostate cancer, 4 had mammary carcinoma, 3 had bronchial carcinoma, and 3 had other cancers. The median preoperative ASIA score was C, postoperatively, the score significantly improved to D (sign test P = 0.002). None of the patients needed stabilization within the follow-up period of up to 56 months.

CONCLUSIONS

In our patient population, minimal intervention could significantly improve neurologic disorders. This outcome was seen over the whole study period. Even though different scoring systems suggest stabilization, our results show that spinal decompression alone might be indicated as well.

Percutaneous Interventional Management of Spinal Metastasis

Spinal metastasis is usually associated with debilitating pain and results in deteriorating life quality. The role of percutaneous management of spinal metastasis has evolved from a diagnostic role to a significant part of therapeutic options in conjunction with conventional management techniques, including radiotherapy and open surgical options. Percutaneous vertebral augmentation (PVA) showed substantial pain reduction, vertebral stabilization, and improvement of quality of life. Minimally invasive local ablative procedures (MILAPs) demonstrated significant pain reduction, local tumor burden control, and improvement of quality of life. Though combined PVA and MILAP's synergistic role in pain reduction may need additional investigation, considering different actions on spine metastasis patients, combining both techniques might beneficial to selected patients. The role of percutaneous management will likely expand since its role in improving patient's quality of life with very minimal procedure-related risk and in conjunction with future technological advancement.

Spinal Instability Neoplastic Score component validation using patient-reported outcomes

OBJECTIVE

The Spinal Instability Neoplastic Score (SINS) correlates with preoperative disability and response to stabilization, with patients with higher scores experiencing greater relief after surgery. However, there is a paucity of data demonstrating the extent to which each component contributes to preoperative clinical status and response to stabilization surgery. The objectives of this study were 2-fold. First, to determine how SINS components correlate with pre- and postoperative patient-reported outcomes (PROs). Second, to determine whether patients with higher SINS (10-12) in the "indeterminate" group respond differently to surgery compared to patients with lower SINS (7-9).

METHODS

SINS and PROs were prospectively collected in 131 patients undergoing stabilization surgery for metastatic spinal disease. Association of SINS components and their individual scores with preoperative symptom burden and PRO symptom change after surgery was analyzed using the Spearman rank correlation coefficient (rho) and the Kruskal-Wallis test. SINS and association with preoperative PRO scores and mean differences in post- and preoperative PRO scores were compared for 2 SINS categories within the indeterminate group (7-9 vs 10-12) using the Wilcoxon 2-sample test and Wilcoxon signed-rank test.

RESULTS

The presence of mechanical pain, followed by metastatic location, correlated most strongly with preoperative functional disability measures and lower disability PRO scores following surgical stabilization. Blastic rather than lytic bone lesions demonstrated stronger association with pain reduction following stabilization. Following surgery, patients with SINS 10-12 demonstrated markedly greater improvement in pain and disability PRO scores nearly across the board compared to patients with SINS 7-9.

CONCLUSIONS

The presence of mechanical pain has the strongest correlation with preoperative disability and improvement in pain and disability PRO scores after surgery. Radiographic components of SINS also correlate with preoperative symptom severity and postoperative PRO, supporting their utilization in evaluation of spinal instability. Among patients with indeterminate SINS, patients with higher scores experience greater reduction in pain and disability PRO scores following surgical stabilization, suggesting that the indeterminate-SINS group includes distinct populations.

Instability and impending instability in patients with vertebral metastatic disease

Metastatic disease commonly involves the spine with an increasing incidence due to a worldwide rise of cancer incidence and a longer survival of patients with osseous metastases. Metastases compromise the mechanical integrity of the vertebra and make it susceptible to fracture. Patients with pathological vertebral fracture often become symptomatic, with mechanical pain generally due to intervertebral instability, and may develop spinal cord compression and neurological deficits. Advances in imaging, radiotherapy, as well as in spinal surgery techniques, have allowed the evolution from conventional palliative external beam radiotherapy to modern stereotactic radiosurgery and from traditional open surgery to less-invasive, and sometimes prophylactic stabilization surgical treatments. It is therefore clear that fracture risk prediction, and maintenance or restoration of intervertebral stability, are important objectives in the management of these patients. Correlation between imaging findings and clinical manifestations is crucial, and a common knowledge base for treatment team members rather than a compartmentalized view is very important. This article reviews the literature on the imaging and clinical diagnosis of intervertebral instability and impending instability in the setting of spine metastatic disease, including the spinal instability neoplastic score, which is a reliable tool for diagnosing unstable or potentially unstable metastatic spinal lesions, and on the different elements considered for treatment.

Sacral chordoma : A review of literature

Chordoma is a rare malignant tumor with predilection for the sacrum. A favorable outcome depends on early diagnosis and surgical excision with tumor free margins.

Aim

To review the incidence and prevalence of sacral chordoma and the appropriate surgical management and formulate a criteria for early diagnosis.

Materials and methods

Thirty eight articles on the subject of sacral chordoma and extrapolated data of clinical and surgical significance.

Results

The commonest presenting feature in patients with sacral chordoma was lower back pain which was worse on sitting and up to a third of these patients had associated urinary tract infections, constipation or symptoms of disc herniation. The hallmark of sacral chordoma is lower back pain with poor response to non-steroidal anti-inflammatory drugs.Disease free eradication in chordoma is rare and not without neurological deficit. The common sacral levels involved ie. S2,3 have to be sacrificed to achieve adequate margins4. Whilst wide excision via posterior surgery shows a decrease in recurrence, the overall survival still remains low.

Rod stiffness effect on adjacent segmental degeneration: a comparative long-term study

Background: Adjacent segment disease (ASD) is a major complication following spinal instrumentation and fusion. The search for of the rod flexibility factors responsible for junctional degeneration is still ongoing. Objective: Determine the rod stiffness and ASD following posterior instrumentation and fusion for lumbar spine and find the proper rod diameter for adult spinal instrumentation for fusion. Subject and methods: Retrospective evaluation of all patients requiring spinal instrumentation to determine the different rod diameter that predispose toward junctional degeneration was completed. All patients requiring spinal instrumentation over a one-year period were studied retrospectively. One-hundred eight-seven patients (mean age 61.6 years) who had undergone decompression and fusion with pedicle screw instrumentation were evaluated. The average follow-up was 4.2 years. The average number of levels fused was 2.9 segments (range: 1-8). Adjacent spinal level pre- and post-operatively was determined on the plain X-rays. Junctional degeneration was defined as new episode of degeneration of the adjacent level on radiologic finding. Asymptomatic patients did not demonstrate junctional degeneration on the routine post-operative X-rays. Results: ASD developed in 15 (8.0%) out of 187 patients, including compression fractures (n=2), spinal stenosis (n=6), and symptomatic disc collapse (n=7). There was a close correlation between the posterior instrument stiffness and the development of ASD (p=0.011). For fusion and fixation with 5.5 mm and 6.0 mm rod diameter, ASD occurred in four (3.7%) out of 108 patients and in 11 (13.9 %) out of 79 patients, resepectively. The incidences of ASD were greater when the posterior instrument used were stiffer in lumbar spine fusion. The pre-operative age, gender, and indication for surgery were not associated with the development of ASD. Conclusion: The prevalence of symptomatic ASD relatively increased with increasing stiffness of spinal implant. The diameter of the longitudinal rod strongly affected the fixator loads, and influenced the stresses in the vertebral endplates. The rod diameter had influence on the stresses in the adjacent spinal motion segment.

Stabilization of Tumor-Associated Craniovertebral Junction Instability: Indications, Operative Variables, and Outcomes

BACKGROUND

Whether primary or metastatic, tumors of the craniovertebral junction (CVJ) are rare and challenging.

OBJECTIVE

To examine the surgical indications, operative variables, and outcomes in patients with tumors of the CVJ undergoing occipitocervical (OC) stabilization.

METHODS

A single-institution, retrospective case series was performed from a prospectively maintained spine database. Patients with primary or metastatic tumors of the CVJ who underwent OC stabilization were identified. Out of 46 patients who underwent OC fusion, 39 were for tumor. Paired t -tests and Wilcoxon rank-sum tests were performed to assess for postoperative changes.

RESULTS

Ten patients (26%) harbored primary tumors, and the remaining 29 (74%) had metastatic disease. Of the metastatic patients, 14 had a neurological deficit, 10 had severe neck pain, and 5 were deemed mechanically unstable. Postoperative visual analog pain scores were significantly reduced at all 3 follow-up times ( P < .001, 95% confidence interval [CI; 3.2, 6.0]; P = .001, 95% CI [2.6, 7.7]; P = .020, 95% CI [0.6, 5.5]). The percentage of patients who were ambulatory and neurologically improved or intact remained stable postoperatively with no significant declines. There were 2 perioperative mortalities (5%), and 13 patients (33%) experienced a major complication.

CONCLUSIONS

In patients with primary or metastatic tumor of the CVJ, OC stabilization using a cervical screw-rod system affixed to a midline-keel buttress plate, with or without posterior decompression, is a reliable method for CVJ stabilization in the oncologic setting. Improvement in pain and preservation of neurological function was seen.

Assessing the utility of the spinal instability neoplastic score (SINS) to predict fracture after conventional radiation therapy (RT) for spinal metastases

PURPOSE

Assessing the stability of spinal metastases is critical for making treatment decisions. The spinal instability neoplastic score (SINS) was developed by the Spine Oncology Study Group to categorize tumor-related lesions; however, data describing its utility in predicting fractures in patients with spinal metastases are limited. The purpose of this study is to assess the validity of SINS in predicting new or worsening fracture after radiation therapy (RT) to spine metastases.

METHODS AND MATERIALS

This is a retrospective analysis of patients treated with conventional RT alone (median total dose, 30 Gy; range, 8-47 Gy; median number of fractions, 10; range, 1-25) for spinal metastasis at Dana-Farber/Brigham and Women's Cancer Center from 2006 to 2013. SINS was calculated for each lesion (range, 0-18). The primary endpoint was time from RT start to radiographically documented new or worsening fracture or last disease assessment.

RESULTS

A total of 203 patients and 250 lesions were included in analysis. The percentages of lesions with SINS of 0 to 6, 7 to 12, and 13 to 18 were 38.8%, 54.8%, and 6.4%, respectively. Of 250 lesions, 20.4% developed new or worsening fractures; 14.4% for SINS 0 to 6, 21.2% for SINS 7 to 12, and 50.0% for SINS 13 to 18. Multivariate analysis adjusted for sex, age, Eastern Cooperative Oncology Group, histology, and total dose indicated that, compared with stable lesions (SINS 0-6), potentially unstable lesions (SINS 7-12) demonstrated a greater likelihood of new or worsening fracture that was not statistically significant (hazard ratio, 1.66; 95% confidence interval, 0.85-3.22; P = .14), and unstable lesions (SINS 13-18) were significantly more likely to develop to new or worsening fracture (hazard ratio, HR,4.37, 95% confidence interval, 1.80-10.61; P = .001).

CONCLUSIONS

In this study of patients undergoing RT for spinal metastases, 20.4% developed new or worsening vertebral fractures. SINS is demonstrated to be a useful tool to assess fracture risk after RT.

Spinal Instability Neoplastic Score (SINS): Reliability Among Spine Fellows and Resident Physicians in Orthopedic Surgery and Neurosurgery

STUDY DESIGN

Reliability analysis.

OBJECTIVES

The Spinal Instability Neoplastic Score (SINS) was developed for assessing patients with spinal neoplasia. It identifies patients who may benefit from surgical consultation or intervention. It also acts as a prognostic tool for surgical decision making. Reliability of SINS has been established for spine surgeons, radiologists, and radiation oncologists, but not yet among spine surgery trainees. The purpose of our study is to determine the reliability of SINS among spine residents and fellows, and its role as an educational tool.

METHODS

Twenty-three residents and 2 spine fellows independently scored 30 de-identified spine tumor cases on 2 occasions, at least 6 weeks apart. Intraclass correlation coefficient (ICC) measured interobserver and intraobserver agreement for total SINS scores. Fleiss's kappa and Cohen's kappa analysis evaluated interobserver and intraobserver agreement of 6 component subscores (location, pain, bone lesion quality, spinal alignment, vertebral body collapse, and posterolateral involvement of spinal elements).

RESULTS

Total SINS scores showed near perfect interobserver (0.990) and intraobserver (0.907) agreement. Fleiss's kappa statistics revealed near perfect agreement for location; substantial for pain; moderate for alignment, vertebral body collapse, and posterolateral involvement; and fair for bone quality (0.948, 0.739, 0.427, 0.550, 0.435, and 0.382). Cohen's kappa statistics revealed near perfect agreement for location and pain, substantial for alignment and vertebral body collapse, and moderate for bone quality and posterolateral involvement (0.954, 0.814, 0.610, 0.671, 0.576, and 0.561, respectively).

CONCLUSIONS

The SINS is a reliable and valuable educational tool for spine fellows and residents learning to judge spinal instability.

Sternal metastasis - the forgotten column and its effect on thoracic spine stability

Sternal metastases are not studied extensively in the literature. There is a paucity of information on their role in metastatic disease. The concept of the fourth column was described by Berg in 1993, and has been proven in case report, clinically and biomechanical studies. The role of the sternum as a support to the thoracic spine is well documented in the trauma patients, but not much is known about its role in cancer patients. This review examines what is known on the role of the fourth column. Following this we have identified two likely scenarios that sternal metastases may impact management: (1) sternal pathological fracture increases the mobility of the semi-rigid thorax with the loss of the biomechanical support of the sternum-rib-thoracic spine complex; and (2) a sternal metastasis increases the risk of fracture, and while being medical treated the thoracic spine should be monitored for acute kyphosis and neurological injury secondarily to the insufficiency of the fourth column.

The Spinal Instability Neoplastic Score: Impact on Oncologic Decision-Making

STUDY DESIGN

Systematic literature review.

OBJECTIVE

To address the following questions in a systematic literature review: 1. How is spinal neoplastic instability defined or classified in the literature before and after the introduction of the Spinal Instability Neoplastic Score (SINS)? 2. How has SINS affected daily clinical practice? 3. Can SINS be used as a prognostic tool?

SUMMARY OF BACKGROUND DATA

Spinal neoplastic-related instability was defined in 2010 and simultaneously SINS was introduced as a novel tool with criteria agreed upon by expert consensus to assess the degree of spinal stability.

METHODS

PubMed, Embase, and clinical trial databases were searched with the key words "spinal neoplasm," "spinal instability," "spinal instability neoplastic score," and synonyms. Studies describing spinal neoplastic-related instability were eligible for inclusion. Primary outcomes included studies describing and/or defining neoplastic-related instability, SINS, and studies using SINS as a prognostic factor.

RESULTS

The search identified 1414 articles, of which 51 met the inclusion criteria. No precise definition or validated assessment tool was used specific to spinal neoplastic-related instability prior to the introduction of SINS. Since the publication of SINS in 2010, the vast majority of the literature regarding spinal instability has used SINS to assess or describe instability. Twelve studies specifically investigated the prognostic value of SINS in patients who underwent radiotherapy or surgery.

CONCLUSION

No consensus could be determined regarding the definition, assessment, or reporting of neoplastic-related instability before introduction of SINS. Defining spinal neoplastic-related instability and the introduction of SINS have led to improved uniform reporting within the spinal neoplastic literature. Currently, the prognostic value of SINS is controversial.

LEVEL OF EVIDENCE

N/A.

Reducing kyphotic deformity by posterior vertebral column resection with 360° osteosynthesis in metastatic epidural spinal cord compression (MESCC)

PURPOSE

Metastatic epidural spinal cord compression (MESCC) often requires anterior-posterior decompression and stabilization. To reduce approach-related complications, single-stage posterolateral vertebrectomy and 360° fusion is often performed. However, a sufficient reduction of kyphotic deformity through this approach has not been reported. The purpose of this study is to investigate the efficacy of kyphotic deformity reduction by this approach in MESCC.

METHODS

A retrospective analysis and chart review was performed for 14 consecutive patients who underwent a vertebrectomy and decompression from a posterolateral approach. Anterior mesh stabilization of the ventral column is used as hypomochlion for the posterior compression manoeuvre, which leads to reduction of the kyphotic deformity.

RESULTS

Pre-operative back pain was 7.2 on a visual analogue scale. Back pain was reduced to 4.4 at discharge and 2.0 at the latest follow-up with a mean follow-up of 12 months (p < 0.001). The Frankel score remains constant or improved from D to E. Radiological segmental kyphosis was corrected from a mean of 16° to 4° (p < 0.001) post-operatively with a loss of 3° at the final follow-up, but still with significant corrections compared with the pre-operative measurements (p < 0.003).

CONCLUSION

Single-stage posterolateral vertebrectomy and reconstruction is a safe and less invasive approach that allows a sufficient reduction of hyperkyphosis and preservation of neurological function in patients with MESCC. This approach is an efficient alternative to anterior-posterior fusion with good pain reduction and improved sagittal profile.

Early surgical occipitocervical stabilization for plasma cell neoplasms at the craniocervical junction: systematic review and proposal of a treatment algorithm

BACKGROUND CONTEXT

Plasma cell neoplasms (PCNs) of the craniocervical junction (CCJ) are rare. Because of their destructive growth, PCNs may induce spinal instability and harbor the risk of sudden death. Therefore, PCNs at the CCJ require special consideration. Although the commonly used primary treatment of PCN is radiotherapy (RT), treatment guidelines are inexistent for CCJ occurrences.

PURPOSE

This study aimed to conduct a systematic review of the literature, evaluate the benefit of early and extended surgical treatment followed by RT, and outline a treatment algorithm based on the data gathered.

STUDY DESIGN/SETTING

Case series and systematic review of all reported cases in the English, Spanish and German medical literature were carried out.

CASE SERIES

retrospective clinical study, tertiary care center (2004-2014). Patients with a lesion of the CCJ (C0-C2) were identified. Clinical charts, imaging data, operative reports, and follow-up data were analyzed.

REVIEW

a systematic literature review was performed using PubMed. Further manuscripts were identified by the web search engine Google.

RESULTS

Our series comprised four patients (one female, three males), mean age 58 years. There was one lesion of C1 and three of C2. Two patients with neck pain received vertebroplasty (C1 and C2, respectively) and RT as primary management. Both developed secondary instability of the CCJ after 12 and 5 months, respectively, and required occipitocervical stabilization (OCS). The other two patients underwent OCS and required no additional surgery and no signs of instability at follow-up. Forty-nine cases of OCS were published previously. Spinal stability was achieved significantly more frequently by OCS than by less invasive or medical interventional treatment options (p=.001; two-sided Fisher exact test).

CONCLUSIONS

Plasma cell neoplasms are highly radiosensitive. However, at the CCJ, a life-threatening instability may occur early and require surgical treatment. Based on personal experience, we favor OCS in this location. A systematic review of the literature supports this approach. We present a summary of our findings in a concise treatment algorithm for PCN of the CCJ.

Late failure of posterior fixation without bone fusion for vertebral metastases

OBJECTIVE

: To verify the frequency of late radiological com-plications in spinal fixation surgeries performed without fu-sion in oncological patients

METHODS

: This is a retrospective analysis analysing failure in cases of non-fused vertebral fixation in an oncology reference hospital between 2009 and 2014. Failure was defined as implant loosening or bre-akage, as well as new angular or translation deformities

RESULTS

: One hundred and five cases were analyzed. The most common site of primary tumor was the breast and the most common place of metastasis was the thoracic spine. The average follow-up was 22.7 months. Nine cases (8%) of failure were reported, with an average time until failure of 9.5 months. The most common failure was implant loosening. No case required further surgery

CONCLUSION

: The occurrence of failure was not different than that reported for fused cases. The time interval until failure was higher than the median of survival of the majority (88%) of cases. Level of Evidence IV, Therapeutic Study.

[Kyphoplasty combined with intraoperative radiotherapy (Kypho-IORT). Alternative therapy for patients with oligometastatic spinal metastases]

BACKGROUND

Due to a more effective systemic therapy the survival of patients suffering from malignant tumors has been significantly improved but a longer life span is often associated with a higher incidence of osseous metastases. The majority of these metastases are localized in the spine causing pain, instability and neurological impairments. The interdisciplinary management of spinal metastases previously consisted of stabilization followed by fractionated external body radiation therapy. A reduction in procedural severity and morbidity as well as consideration of self-sufficiency and hospitalization time are important target parameters for these palliative patients.

METHOD AND RESULTS

Kyphoplasty combined with intraoperative radiotherapy (Kypho-IORT) is one of several modern treatment options, which involves a minimally invasive procedure with local high-dose transpedicular irradiation of the spine with low-energy (50 kV) X-rays. Immediately following irradiation, stabilization of the spine is carried out using kyphoplasty via the same access route so that a single stage procedure with excellent pain reduction and good local tumor control can be achieved. This article presents clinical data for this procedure and the different fields of indications are critically reviewed and compared to other therapy options. Methodological improvements and options for further individualization of therapy are demonstrated.

CONCLUSION

The Kypho-IORT procedure is a safe, feasible and beneficial modern treatment option for instant stabilization and local tumor control in patients with spinal metastases. More than 100 operations have been successfully performed so that the method can be deemed suitable for inclusion in the clinical routine. A phase II dose escalation study has now been completed and submitted for publication and a 2-arm non-inferiority trial (phase III study) for comparison with conventional irradiation is in progress.

Contemporary Treatment Strategy for Spinal Metastasis: The “LMNOP” System

The choice of treatment for spinal metastasis is complex because (1) it depends on several inter-related clinical and radiologic factors, and (2) a wide range of management options has evolved in recent years. While radiation therapy and surgery remain the cornerstones of treatment, radiosurgery and percutaneous vertebral augmentation have also established a role. Classification systems have been developed to aid in the decision-making process, and each has different strengths and weaknesses. The comprehensive scoring systems developed to date provide an estimate of life expectancy, but do not provide much advice on the choice of treatment. We propose a new decision model that describes the key factors in formulating the management plan, while recognizing that the care of each patient remains highly individualized. The system also incorporates the latest changes in technology. The LMNOP system evaluates the number of spinal Levels involved and the Location of disease in the spine (L), Mechanical instability (M), Neurology (N), Oncology (O), Patient fitness, Prognosis and response to Prior therapy (P).

Optimal approach to circumferential decompression and reconstruction for thoracic spine metastatic disease

BACKGROUND

Circumferential decompression has been demonstrated to be the first-line therapy for patients with metastatic tumors in the thoracic spine requiring surgical intervention. However, there is significant debate regarding whether these tumors are best accessed anteriorly utilizing a thoracotomy or posteriorly. We used decision analysis to determine which approach yields greater health-related quality of life (QOL).

METHODS

We searched Medline, Embase, and the Cochrane Library for relevant articles published between 1990 and 2011 on anterior and posterior approaches to metastatic disease in the thoracic spine. QOL values for major treatment outcomes were determined using the existing literature. Separate models were created for ambulatory and nonambulatory patients. A Monte Carlo simulation and sensitivity analyses were used to determine which treatment strategy resulted in the highest QOL.

RESULTS

For ambulatory patients, an anterior approach resulted in a slightly higher QOL, and for nonambulatory patients, a posterior approach was favored, but these differences were not statistically significant.

CONCLUSIONS

Using a decision-analytic model, we found no significant difference in QOL resulting from anterior versus posterior approaches to metastatic lesions in the thoracic spine. Decisions should instead be based on surgeon comfort, tumor characteristics, anatomy of the lesion, patient-related factors, and goals of the operation.

Interobserver agreement for the spine instability neoplastic score varies according to the experience of the evaluator

OBJECTIVES

To evaluate the interobserver agreement for the Neoplastic Spine Instability Score (SINS) among spine surgeons with or without experience in vertebral metastasis treatment and physicians in other specialties.

METHODS

Case descriptions were produced based on the medical records of 40 patients with vertebral metastases. The descriptions were then published online. Physicians were invited to evaluate the descriptions by answering questions according to the Neoplastic Spine Instability Score (SINS). The agreement among physicians was calculated using the kappa coefficient.

RESULTS

Seventeen physicians agreed to participate: three highly experienced spine surgeons, seven less-experienced spine surgeons, three surgeons of other specialties, and four general practitioners (n = 17). The agreement for the final SINS score among all participants was fair, and it varied according to the SINS component. The agreement was substantial for the spine location only. The agreement was higher among experienced surgeons. The agreement was nearly perfect for spinal location among the spine surgeons who were highly experienced in vertebral metastases.

CONCLUSIONS

This study demonstrates that the experience of the evaluator has an impact on SINS scale classification. The interobserver agreement was only fair among physicians who were not spine surgeons and among spine surgeons who were not experienced in the treatment of vertebral metastases, which may limit the use of the SINS scale for the screening of unstable lesions by less-experienced evaluators.

Less invasive approaches for the treatment of cervical schwannomas: our experience

PURPOSE

The purpose of our paper is to illustrate our experience with minimally invasive approaches for the treatment of cervical schwannomas. Moreover, a brief review of the literature was conducted.

METHODS

All data regarding patients treated for cervical schwannomas were retrospectively revised. Site, size and extension of the lesions and preoperative neurological status were obtained through re-examination of neuroimaging and clinical records. Postoperative clinical examinations and radiological images were available for all patients. The clinical course was documented using the visual analog scale (VAS), Karnofsky score (KPS) and the Klekamp-Samii score system.

RESULTS

Sixteen patients harboring cervical schwannomas were treated from 2003 to 2009. Hemilaminectomy was performed in eight cases, subtotal hemilaminectomy in four cases, interlaminar fenestration in two cases, osteoplastic hemilaminotomy and laminoplasty in one case each. Postoperative neuroimaging revealed complete removal of the lesion and no signs of spinal instability. At discharge, neurological improvement was observed in 14 patients and all patients demonstrated reduction of VAS score and improvement of KPS and Klekamp-Samii's score.

CONCLUSIONS

Minimal access procedures are increasingly gaining popularity but their use is poorly described in the treatment of cervical tumors. Less invasive approaches may effectively be used instead of traditional laminectomy in the treatment of cervical tumors, especially schwannomas, providing less iatrogenic traumatism and preventing postsurgical spinal instability. Modern neuroimaging allows adequate preoperative planning and microsurgical techniques provide adequate execution of the surgical act. The procedure has to be tailored case by case considering the specific lesional features and the individual anatomical situation.

Long-term outcomes following en bloc resection for sacral tumor: a retrospective analysis of 93 cases

Sacral tumors are rare. Appropriate surgical resection is crucial to treat the disease while minimizing disease recurrence. We present the results of 93 patients with sacral tumors to analyze the long-term functional and oncological results of patients undergoing en bloc resection. The medical data between January 2003 and July 2010 was retrospectively reviewed. None of the 93 patients died intra- or postoperatively. Patients undergoing intralesional curettage (range, 6500-25,000 mL; mean, 13,500 mL) lost more blood than those patients with wide excision (range, 1000-8100 mL; mean, 3590 mL). Mean follow-up duration from the time of surgery until most recent clinic visit or death was 44.5 months (range, 6-105 months). This study is an educational tool regarding primary sacral tumors and provides evidence on the treatment. It presents results from a large group of patients with sacral tumor. After follow-up, we did not find that sacrificed nerve roots and surgical margins have an impact on the recurrence of the tumor. Patients undergoing intralesional curettage lost more blood than those patients with wide excision. Postoperative bladder/bowel dysfunction was more severe for patients with removal of S1 and S2.

Spinal instability neoplastic score: an analysis of reliability and validity from the spine oncology study group

PURPOSE

Standardized indications for treatment of tumor-related spinal instability are hampered by the lack of a valid and reliable classification system. The objective of this study was to determine the interobserver reliability, intraobserver reliability, and predictive validity of the Spinal Instability Neoplastic Score (SINS).

METHODS

Clinical and radiographic data from 30 patients with spinal tumors were classified as stable, potentially unstable, and unstable by members of the Spine Oncology Study Group. The median category for each patient case (consensus opinion) was used as the gold standard for predictive validity testing. On two occasions at least 6 weeks apart, each rater also scored each patient using SINS. Each total score was converted into a three-category data field, with 0 to 6 as stable, 7 to 12 as potentially unstable, and 13 to 18 as unstable.

RESULTS

The κ statistics for interobserver reliability were 0.790, 0.841, 0.244, 0.456, 0.462, and 0.492 for the fields of location, pain, bone quality, alignment, vertebral body collapse, and posterolateral involvement, respectively. The κ statistics for intraobserver reliability were 0.806, 0.859, 0.528, 0.614, 0.590, and 0.662 for the same respective fields. Intraclass correlation coefficients for inter- and intraobserver reliability of total SINS score were 0.846 (95% CI, 0.773 to 0.911) and 0.886 (95% CI, 0.868 to 0.902), respectively. The κ statistic for predictive validity was 0.712 (95% CI, 0.676 to 0.766).

CONCLUSION

SINS demonstrated near-perfect inter- and intraobserver reliability in determining three clinically relevant categories of stability. The sensitivity and specificity of SINS for potentially unstable or unstable lesions were 95.7% and 79.5%, respectively.

Appropriateness of lumbar spine referrals to a neurosurgical service

BACKGROUND

Patients with lumbar spine complaints are often referred for surgical assessment. Only those with clinical and radiological evidence of nerve root compression are potential candidates for surgery and appropriate for surgical assessment. This study examines the appropriateness of lumbar spine referrals made to neurosurgeons in Edmonton, Alberta.

METHODS

Lumbar spine referrals to a group of ten neurosurgeons at the University of Alberta were reviewed over three two month intervals. Clinical criteria for "appropriateness" for surgical assessment were as follows: •"Appropriate" referrals were those that stated leg pain was the chief complaint, or those that described physical exam evidence of neurological deficit, and imaging reports (CT or MRI) were positive for nerve root compression. •"Uncertain" referrals were those that reported both back and leg pain without specifying which was greater, without mention of neurologic deficit, and when at least possible nerve root compression was reported on imaging. •"Inappropriate" referrals contained no mention of leg symptoms or signs of neurological deficit, and/or had no description of nerve root compression on imaging.

RESULTS

Of the 303 referrals collected, 80 (26%) were appropriate, 92 (30%) were uncertain and 131 (44%) were inappropriate for surgical assessment.

CONCLUSIONS

Physicians seeking specialist consultations for patients with lumbar spine complaints need to be better informed of the criteria which indicate an appropriate referral for surgical treatment, namely clinical and radiological evidence of nerve root compression. Avoiding inappropriate referrals could reduce wait-times for both surgical consultation and lumbar spine surgery for those patients requiring it.

The surgical management of metastatic epidural compression of the spinal cord

Metastatic epidural compression of the spinal cord is a significant source of morbidity in patients with systemic cancer. With improved oncological treatment, survival in these patients is improving and metastatic cord compression is encountered increasingly often. The treatment is mostly palliative. Surgical management involves early circumferential decompression of the cord with concomitant stabilisation of the spine. Patients with radiosensitive tumours without cord compression benefit from radiotherapy. Spinal stereotactic radiosurgery and minimally invasive techniques, such as vertebroplasty and kyphoplasty, with or without radiofrequency ablation, are promising options for treatment and are beginning to be used in selected patients with spinal metastases. In this paper we review the surgical management of patients with metastatic epidural spinal cord compression.

Decision making in the surgical treatment of cervical spine metastases

STUDY DESIGN

Qualitative systematic review of the literature.

OBJECTIVE

To determine whether surgical indications and techniques are influenced by the region of the cervical spine (occipitocervical, midcervical, and cervicothoracic junctions).

SUMMARY OF BACKGROUND DATA

There are distinct differences in the anatomic as well as biomechanical characteristics at the occipitocervical junction (C0-C2), subaxial spine (C3-C6), and the cervicothoracic junction (C7-T2), and there is no information on whether these differences influence the decision to intervene surgically or influence the choice of surgical approach.

METHODS

A systematic review was designed to answer 2 primary research questions that were determined through consensus among a panel of experts drawn from the Spine Oncology Study Group: 1. Is the decision to operate influenced by the anatomic region of the cervical spine? 2. Is the operative approach influenced by the anatomic region of the cervical spine?

RESULTS

For C0-C2 disease, posterior approaches are favored in the majority of cases. In the subaxial cervical spine (C3-C6), anterior approaches were preferred in the majority of cases. A combined anterior/posterior approach was favored for multilevel disease, circumferential tumor involvement, and poor bone quality. At the cervicothoracic junction (C7-T1), anterior or posterior approach was used for decompression. Three column reconstruction from a single posterior approach was an increasingly commonly performed procedure.

CONCLUSION

Although there are no level-1 studies to guide decision-making in this area, a literature review does provide some general guidelines for clinical management. Metastatic involvement of junctional regions of the cervical spine (Occ-C2 and C7-T1) and/or kyphosis and collapse involving any region of the cervical spine are key determinants influencing the decision to stabilize the spine.Posterior techniques are favored at the occipitocervical junction, anterior techniques are generally recommended to in the subaxial cervical spine, and either anterior or posterior approaches can be used at the cervicothoracic junction.

Diagnosis and staging of spine tumors

Persistent axial pain with or without neurologic changes should prompt workup for a possible tumor of the spine. Metastatic disease is more predominant than primary tumors, but still needs adequate evaluation before any management. The various steps of evaluation, diagnosis, and staging are reviewed.

CyberKnife radiosurgery for malignant spinal tumors: characterization of well-suited patients

STUDY DESIGN

A prospective interventional case-series study.

OBJECTIVE

To provide clinical results of CyberKnife fiducial-free spinal radiosurgery. The study focused on patients with no more than 2 malignant spinal tumors.

SUMMARY OF BACKGROUND DATA

Progress in frameless radiosurgical technology has enabled the application of radiosurgery to the spine. The CyberKnife System has been used extensively for spine radiosurgery. Until recently, the system required metallic fiducial implants for precise target tracking. Fiducial-free spinal radiosurgery with the CyberKnife has recently become possible, but until now clinical results obtained with this method had been limited.

METHODS

From August 2005 until October 2007, a consecutive series of 102 patients with a total of 134 malignant spinal tumors were selected for single-fraction, fiducial-free CyberKnife radiosurgery (CKRS). The study was limited to patients with a maximum of 2 tumors. Malignant primaries included breast cancer in 23 (22.6%) patients, renal cancer in 20 (19.6%) patients, gastro-intestinal cancers in 12 (11.8%) patients, prostate cancer each in 12 (11.8%) patients, lung cancer in 9 (8.9%) patients, sarcomas in 7 (6.9%) patients. A variety of other malignant tumors were found in 19 (18.6%) patients. Patients with spinal cord compression or evidence of myelopathy were excluded. The sequential neurologic status was recorded. Tumor-associated spinal pain was prospectively scored according to the visual analogue scale (VAS).

RESULTS

Of 102 individuals, 22 (21.6%) died due to progression of their systemic disease. Mean survival after CKRS was 1.4 years (CI: 1.2-1.6). Karnofsky performance score was the only independent predictor of survival after radiosurgery on log-rank test (P < 0.0001), and on Cox regression analysis (hazard ratio, 0.864, P < 0.0001, CI: 0.809-0.922). Median survival after initial tumor diagnosis was 18.4 years (CI: 15.1-23.4). Two (2%) patients suffered complications after radiosurgery; a tumor hemorrhage occurred in one, and another developed spinal instability. These and 2 other patients were stabilized by kyphoplasty. Neurotoxicity or myelopathy was not observed. Local tumor control 15 months after CKRS was 98% (95% CI: 89-99%). Tumor-associated pain was observed in 52 (51%) patients. In these patients the median pretreatment pain score of VAS = 7 (95% CI: 6-7) was significantly reduced to VAS = 1 (95% CI: 4-6) (P < 0.001) within 1 week after CKRS. Analysis of variance identified the initial pain score as the only significant variable to predict pain reduction after CKRS (P < 0.03). Pain recurrence in correlation with tumor recurrence was observed for 3 (6%) patients.

CONCLUSION

Spinal radiosurgery with the CyberKnife technology is a nonivasive, safe, and effective treatment method for patients with 1 or 2 small spinal malignant tumors. The best benefit of the treatment can be expected in patients with good to excellent clinical condition and patients with severe tumor associated pain.

Evaluation of factors associated with postoperative infection following sacral tumor resection

Object

Resection of sacral tumors has been shown to improve survival, since the oncological prognosis is commonly correlated with the extent of local tumor control. However, extensive soft-tissue resection in close proximity to the rectum may predispose patients to wound complications and infection. To identify potential risk factors, a review of clinical outcomes for sacral tumor resections over the past 5 years at a single institution was completed, paying special attention to procedure-related complications.

Methods

Between 2002 and 2007, 46 patients with sacral tumors were treated with surgery. Demographic data, details of surgery, type of tumor, and patient characteristics associated with surgical site infections (SSIs) were collected; these data included presence of the following variables: diabetes, obesity, smoking, steroid use, previous surgery, previous radiation, cerebrospinal fluid leak, number of spinal levels exposed, instrumentation, number of surgeons scrubbed in to the procedure, serum albumin level, and combined anterior-posterior approach. Logistic regression analysis was implemented to find an association of such variables with the presence of SSI.

Results

A total of 46 patients were treated for sacral tumor resections; 20 were male (43%) and 26 were female (57%), with an average age of 46 years (range 11–83 years). Histopathological findings included the following: chordoma in 19 (41%), ependymoma in 5 (11%), rectal adenocarcinoma in 5 (11%), giant cell tumor in 4 (9%), and other in 13 (28%). There were 18 cases of wound infection (39%), and 2 cases of repeat surgery for tumor recurrence (1 chordoma and 1 giant cell tumor). Factors associated with increased likelihood of infection included previous lumbosacral surgery (p = 0.0184; odds ratio [OR] 7.955) and number of surgeons scrubbed in to the operation (p = 0.0332; OR 4.018). Increasing age (p = 0.0864; OR 1.031), presence of complex soft-tissue reconstruction (p = 0.118; OR 3.789), and bowel and bladder dysfunction (p = 0.119; OR 2.667) demonstrated a trend toward increased risk of SSI.

Conclusions

Patients undergoing sacral tumor surgery may be at greater risk for developing wound complications due to the extensive soft-tissue resections often required, especially with the increased potential for contamination from the neighboring rectum. In this study, it appears that previous lumbosacral surgery, number of surgeons scrubbed in, patient age, bowel and bladder dysfunction, and complex tissue reconstruction may predict those patients more prone to developing postoperative SSIs.

Uncorrected sagittal plane imbalance predisposes to symptomatic instrumentation failure

BACKGROUND CONTEXT

Elucidation of the factors responsible for symptomatic failure of spinal instrumentation has been a keen interest for many investigators.

PURPOSE

To quantitate the number of symptomatic instrumentation failures (SIFs) encountered during a 2-year period. The effect of sagittal plane imbalance (corrected or uncorrected) on the rate of SIF was evaluated.

STUDY DESIGN

Retrospective evaluation of all patients requiring spinal instrumentation to determine which factors predispose toward instrumentation failure.

PATIENT SAMPLE

All patients requiring spinal instrumentation over a 2-year period were retrospectively studied.

OUTCOME MEASURES

Sagittal plane imbalance pre- and postoperatively was determined using Cobb angle analysis on plain X-rays. SIF was defined as screw back-out and/or breakage, pseudarthrosis, cage migration, or rod disconnection in patients with concordant symptoms. Asymptomatic patients did not demonstrate instrumentation failure on the routine postoperative X-rays.

METHODS

Of the 355 patients who fit the criteria, 47 patients presented with either idiopathic or secondary sagittal plane deformity preoperatively. Additionally, long-segment fixation, smoking, age, and fixation across junctional segments were evaluated as risk factors for SIF.

RESULTS

Of the 47 patients with sagittal plane deformity, 40 patients (85%) achieved correction demonstrated on postoperative radiographs whereas in 7 (15%), the sagittal plane imbalance was not corrected. Of these seven cases, five suffered instrumentation failure (failure rate 71.5%) versus no instrumentation failures (failure rate 0%) for the remaining 40 patients. SIF was demonstrated in 10 patients overall (failure rate of 2.8%). There was no correlation found between factors such as age, indications for surgery, or long-segment fixation, and instrumentation failure.

CONCLUSIONS

Failure to correct sagittal plane deformity intraoperatively predisposes patients to SIF regardless of age, level of surgery, or indication of surgery.

MINIMALLY INVASIVE POSTERIOR OSTEOTOMIES

OBJECTIVE

Surgery for thoracolumbar deformity can lead to significant muscle injury, excessive blood loss, and severe postoperative pain. The aim of the following studies was to determine the feasibility of minimally invasive posterior thoracic corpectomy and thoracolumbar osteotomy techniques for deformity in human cadavers and select clinical cases.

METHODS

Human cadaveric specimens were procured for thoracic corpectomy and Smith-Petersen and pedicle subtraction osteotomy using a minimally invasive approach. Post-procedural computed tomography was used to assess the degree of decompression following corpectomy and the extent of bone resection after osteotomy. Pre and post-osteotomy closure Cobb angles were measured to evaluate the degree of correction achieved.

RESULTS

The minimally invasive lateral extracavitary approach for thoracic corpectomy provided adequate exposure and allowed excellent spinal canal decompression while minimizing tissue disruption. Nearly complete osteotomies of both types could be achieved through a tubular retractor with a modest change in Cobb angle.

CONCLUSION

These techniques may play a role in deformity surgery for select cases with further technological advancements.

Trends in pathological vertebral fractures in the United States: 1993 to 2004

OBJECT

Pathological vertebral fractures (PVFs) are an increasingly important cause of disability and have many clinical and economic implications. The authors examined trends in epidemiology and surgical management of pathological vertebral fractures in the US between 1993 and 2004.

METHODS

The Nationwide Inpatient Sample database was used to analyze data collected from 1993 through 2004 to determine general trends in PVFs. Patients with PVFs were identified using the appropriate International Classification of Diseases, 9th Revision (ICD-9) diagnostic code (ICD-9 733.13). Trends in vertebral augmentation procedures and spinal fusions as well as comparison with incidences of other major pathological fractures, such as hip and upper limb, were also examined.

RESULTS

In 2004, there were more than 55,000 inpatient admissions for PVFs. The majority of patients admitted were women (78%) in the 65 to 84 year-age group (60%). Medicare accounted for greater than 80% of insurance, and nearly 50% of all patients were admitted from the emergency department. The mean duration of hospitalization has continued to decrease, from 8.1 days in 1993 to 5.4 days in 2004. The mortality rate has remained relatively constant at approximately 1.5%. The discharge disposition has continued to change with an increasing number of patients being discharged to other institutions such as nursing homes and rehabilitation facilities. There was a staggering increase in the number of vertebral augmentation procedures performed between 1993 and 2004. The "national bill" for inpatient hospitalizations for PVFs totaled $1.3 billion in 2004.

CONCLUSIONS

With the continued aging of the population, PVFs represent an important cause of disability and a significant source of healthcare resource utilization.

Treatment of Vertebral Tumor with Posterior Wall Defect Using Image-guided Radiofrequency Ablation Combined with Vertebroplasty: Preliminary Results in 12 Patients

PURPOSE

To evaluate the safety and clinical benefit of vertebral tumor treatment by combined radiofrequency ablation (RFA) and vertebroplasty, for pain reduction in patients who are unable to benefit from noninvasive treatment methods.

MATERIALS AND METHODS

Twelve patients with painful vertebral tumors with posterior wall defect, in whom medical treatment together with radiation therapy and/or chemotherapy had failed, were treated with RFA combined with vertebroplasty. Procedures were performed using multislice CT-fluoroscopy and lateral C-arm fluoroscopic guidance. All patients had posterior wall defects of the vertebra being treated. Ten had lytic posterior wall destruction and two had posterior wall fracture. The visual analog scale (VAS) pain score was measured before, one week after, and three months after treatment. VAS patient satisfaction score was measured before and one week after treatment. The VAS score range was 0-20. The analgesic use was evaluated before and four weeks after treatment and complications were monitored.

RESULTS

Combined RFA and vertebroplasty treatment was technically successful in all patients. Pain significantly decreased after treatment: the mean VAS pain score before treatment was 17.33 +/- 2.46 (range, 13-20) versus 9.25 +/- 4.81 (range, 2-18) one week after treatment (P < .001) and was 7.00 +/- 5.26 (range, 1-14) three months after treatment (P = .020). The mean VAS satisfaction score of all patients was 15.83 +/- 4.26 (range, 4-20). Analgesic use decreased after treatment. No serious treatment related complications occurred.

CONCLUSION

RFA in combination with vertebroplasty for treating vertebral tumors with posterior wall defect appeared safe, and reduced pain substantially in patients who did not benefit from other noninvasive treatment methods.

Pathological fracture of the atlas secondary to plasmacytoma

Plasmacytoma of the atlas with pathological fracture has not been previously reported. A 72-year-old man was admitted to our clinic with a 5-month history of occipital headache. Neurologic examination revealed mild occipital neuralgia, difficulty with movements of the cranium, hyperactive deep tendon reflexes, but no Babinski sign. Magnetic resonance imaging (MRI) of the cervical spine showed a 1x2 cm well-circumscribed extradural mass, with lytic destruction and fracture of the lateral mass of C1. Preoperatively dynamic cervical radiographs showed no instability. Using a transcondylar approach, the tumor was removed, and posterolateral fixation and fusion (using iliac autograft) was performed. Biopsy was reported as plasmacytoma. The patient was pain-free with bony fusion 3 years after surgery. This paper presents a pathologic fracture of C1. Although the primary treatment of plasmacytoma is non-surgical, the need for tissue diagnosis in relevant areas may dictate an open biopsy procedure. Such cases may require a decompression and reconstruction procedure.