Evolving Trends in the Use of Sacroiliac Fusion From 2015 to 2020

STUDY DESIGN

Retrospective cohort analysis.

OBJECTIVE

To assess the evolution of patients undergoing sacroiliac (SI) fusion with minimally invasive surgery (MIS) relative to open approaches.

SUMMARY OF BACKGROUND DATA

The SI joint can be a contributor to lumbopelvic symptoms. The MIS approach to SI fusion has been shown to have fewer complications compared with the open approach. Recent trends and evolved patient populations have not been well-characterized.

MATERIALS AND METHODS

Data were abstracted from the large, national, multi-insurance, administrative 2015-2020 M151 PearlDiver database. The incidence, trends, and patient characteristics of MIS, as well as open, SI fusions for adult patients with degenerative indications, were determined. Univariable and multivariable analyses were then performed to compare the MIS relative to open populations. The primary outcome was to assess the trends of MIS and open approaches for SI fusions.

RESULTS

In total, 11,217 SI fusions were identified (of which 81.7% were MIS), with a clear increase in numbers over the years from 2015 (n=1318, 62.3% of which were MIS) to 2020 (n=3214 86.6% of which were MIS). Independent predictors of MIS (as opposed to open) SI fusion included: older age (odds ratio [OR] 1.09 per decade increase), higher Elixhauser-Comorbidity Index (OR 1.04 per two-point increase), and geographic region (relative to South, Northeast OR 1.20 and West OR 1.64). As might be expected, 90-day adverse events were lower for MIS than open cases (OR 0.73).

CONCLUSION

The presented data quantify the increasing incidence of SI fusions over the years, with the increase being driven by MIS cases. This was largely related to an expanded population (those who are older and with greater comorbidity), fitting the definition of disruptive technology with lesser adverse events than open procedures. Nonetheless, geographic variation highlights the differential adoption of this technology.

Minimally Invasive SI Joint Fusion Procedures for Chronic SI Joint Pain: Systematic Review and Meta-Analysis of Safety and Efficacy

BACKGROUND

Sacroiliac (SI) joint fusion is increasingly used to treat chronic SI joint pain. Multiple surgical approaches are now available.

METHODS

Data abstraction and random effects meta-analysis of safety and efficacy outcomes from published patient cohorts. Patient-reported outcomes (PROs) and safety measures were stratified by surgical technique: transiliac, including lateral transiliac (LTI) and posterolateral transiliac (PLTI), and posterior interpositional (PI) procedures.

RESULTS

Fifty-seven cohorts of 2851 patients were identified, including 43 cohorts (2126 patients) for LTI, 6 cohorts (228 patients) for PLTI, and 8 cohorts (497 patients) for PI procedures. Randomized trials were only available for LTI. PROs were available for pain (numeric rating scale) in 57 cohorts (2851 patients) and disability (Oswestry Disability Index [ODI]) in 37 cohorts (1978 patients).All studies with PROs showed improvement from baseline after surgery. Meta-analytic improvements in pain scores were highest for LTI (4.8 points [0-10 scale]), slightly lower for PLTI (4.2 points), and lowest for PI procedures (3.8 points, P = 0.1533). Mean improvements in ODI scores were highest for LTI (25.9 points), lowest for PLTI procedures (6.8 points), and intermediate for PI (16.3 points, P = 0.0095).For safety outcomes, acute symptomatic implant malposition was 0.43% for LTI, 0% for PLTI, and 0.2% for PI procedures. Wound infection was reported in 0.15% of LTI, 0% of PLTI, and 0% of PI procedures. Bleeding requiring surgical intervention was reported in 0.04% of LTI procedures and not reported for PLTI or PI. Breakage and migration were not reported for any device. Radiographic imaging evaluation reporting implant placement accuracy and fusion was only available for LTI.

DISCUSSION

Literature support for SI joint fusion is growing. The LTI procedure contains the largest body of available evidence and shows the largest improvements in pain and ODI. Only LTI procedures have independent radiographic evidence of fusion and implant placement. The adverse event rate for all procedures was low.

LEVEL OF EVIDENCE: 1

Longitudinal Comparative Analysis of Complications and Subsequent Interventions Following Stand-Alone Interspinous Spacers, Open Decompression, or Fusion for Lumbar Stenosis

INTRODUCTION

For individuals with lumbar spinal stenosis (LSS), minimally invasive procedures such as an interspinous spacer device without decompression or fusion (ISD) or open surgery (i.e., open decompression or fusion) may relieve symptoms and improve functions when patients fail to respond to conservative therapies. This research compares longitudinal postoperative outcomes and rates of subsequent interventions between LSS patients treated with ISD and those with open decompression or fusion as their first surgical intervention.

METHODS

This retrospective, comparative claims analysis identified patients age ≥ 50 years with LSS diagnosis and with a qualifying procedure during 2017-2021 in the Medicare database which includes healthcare encounters in inpatient and outpatient settings. Patients were followed from the qualifying procedure until end of data availability. The outcomes assessed during the follow-up included subsequent surgical interventions, including subsequent fusion and lumbar spine surgeries, long-term complications, and short-term life-threatening events. Additionally, the costs to Medicare during a 3-year follow-up were calculated. Cox proportional hazards, logistic regression, and generalized linear models were used to compare outcomes and costs, adjusted for baseline characteristics.

RESULTS

A total of 400,685 patients who received a qualifying procedure were identified (mean age 71.5 years, 50.7% male). Compared to ISD patients, patients receiving open surgery (i.e., decompression and/or fusion) were more likely to have a subsequent fusion [hazard ratio (HR), 95% confidence intervals (CI): 1.49 (1.17, 1.89)-2.54 (2.00, 3.23)] or other lumbar spine surgery [HR (CI): 3.05 (2.18, 4.27)-5.72 (4.08, 8.02)]. Short-term life-threatening events [odds ratio (CI): 2.42 (2.03, 2.88)-6.36 (5.33, 7.57)] and long-term complications [HR (CI): 1:31 (1.13, 1.52)-2.38 (2.05, 2.75)] were more likely among the open surgery cohorts. Adjusted mean index costs were lowest for decompression alone (US$7001) and highest for fusion alone ($33,868). ISD patients had significantly lower 1-year complication-related costs than all surgery cohorts and lower 3-year all-cause costs than fusion cohorts.

CONCLUSIONS

ISD resulted in lower risks of short- and long-term complications and lower long-term costs than open decompression and fusion surgeries as a first surgical intervention for LSS.

A comparison of in-hospital outcomes after elective anterior cervical discectomy and fusion in cases with and without Parkinson's Disease

Background

Following orthopedic surgery, patients with Parkinson's disease (PD) have been shown to have high rates of surgical complications, and some studies suggest that PD may be associated with greater risk for postoperative medical complications. As complication rates are critical to consider for elective surgery planning, the current study aimed to describe the association of PD with medical complications following anterior cervical discectomy and fusion (ACDF), the most commonly performed procedure to treat cervical degenerative pathology.

Methods

The 2008-2018 National Inpatient Sample database was queried for cases involving elective ACDF. Demographics and comorbidities were extracted using ICD codes. Cases were propensity matched based on demographic and comorbidity burden, and logistic regression was used to compare in-hospital complications between patients with and without PD.

Results

After weighting, a total of 1,273,437 elective ACDF cases were identified, of which 3948 (0.31%) involved cases with PD. After 1:1 propensity score matching by demographic and comorbidity variables, there were no differences between the PD and non-PD cohorts. Logistic regression models constructed for the matched and unmatched populations showed that PD cases have greater odds of in-hospital minor adverse events with no differences in odds of serious adverse events or mortality.

Conclusions

After matching for demographics and comorbidity burden, PD cases undergoing elective ACDF had slightly longer length of stay and greater risk for minor adverse events but had similar rates of serious adverse events and mortality. These findings are important for surgeons and patients to consider when making decisions about surgical intervention.

Better Functional Recovery After Single-Level Compared With Two-Level Posterolateral Lumbar Fusion

Background

Multiple studies describe the outcomes of patients undergoing single-level and multilevel posterolateral lumbar fusion (PLF). However, a comparison of outcomes between single-level and two-level PLF is lacking. The aim of this prospective cohort study was to compare outcomes between single-level and two-level instrumented PLF.

Methods

A total of 42 patients were enrolled at nine US centers between October 2015 and June 2017. Data included radiologic outcomes, visual analog scale (VAS) Back and Leg Pain, disability per the Oswestry Disability Index (ODI), and health-related quality of life (QoL) per 36-Item Short Form Survey version 2.0 (SF-36v2) at six weeks and three, six, 12, and 24 months.

Results

Twelve-month and 24-month follow-ups were completed by 38 (90.5%) and 32 (76.2%) subjects, respectively. The average age was 67 years, and 54.8% were female. Twenty-six received single-level PLF, and 16 received two-level PLF. In the single-level group, there was one reoperation, two postoperative infections, and one dural tear. In the two-level group, there was one postoperative infection. The surgeon computed tomography (CT)-based evaluation of fusion rate was 67.6% (25/37) at 12-month follow-up and 94.1% (32/34) at 24-month follow-up. The third-party evaluation of fusion rate was 52.8% (19/36) at six months, 81.1% (30/37) at 12 months, and 86.5% (32/37) at 24 months. There was a tendency toward a higher fusion rate in single-level compared with two-level PLF. The ODI, SF-36v2 Mental Component Score (MCS), and VAS Back Pain and Leg Pain outcomes improved by the first follow-up visit in both the single-level and two-level groups. Improvement in the ODI was 5.86 (95% confidence interval (CI): 0.03-11.69) points greater in the single-level group compared with the two-level group.

Conclusions

Compared with the two-level PLF subjects, single-level PLF subjects had better functional outcomes and reported higher satisfaction with the outcome of surgery but showed similar fusion, pain, and generic health-related quality of life outcomes. Both single-level and two-level PLF subjects demonstrated high fusion rates in association with improvements in pain, functional, and quality of life outcomes, as well as high satisfaction levels.

Cement Augmentation of Vertebral Compression Fractures May Be Safely Considered in the Very Elderly

Objective

The objective of the current study was to perform a retrospective review of a national database to assess the safety of cement augmentation for vertebral compression fractures in geriatric populations in varying age categories.

Methods

The 2005–2016 National Surgical Quality Improvement Program databases were queried to identify patients undergoing kyphoplasty or vertebroplasty in the following age categories: 60–69, 70–79, 80–89, and 90+ years old. Demographic variables, comorbidity status, procedure type, provider specialty, inpatient/outpatient status, number of procedure levels, and periprocedure complications were compared between age categories using chi-square analysis. Multivariate logistic regressions controlling for patient and procedural variables were then performed to assess the relative periprocedure risks of adverse outcomes of patients in the different age categories relative to those who were 60–69 years old.

Results

For the 60–69, 70–79, 80–89, and 90+ years old cohorts, 486, 822, 937, and 215 patients were identified, respectively. After controlling for patient and procedural variables, 30-day any adverse events, serious adverse events, reoperation, readmission, and mortality were not different for the respective age categories. Cases in the 80- to 89-year-old cohort were at increased risk of minor adverse events compared to cases in the 60- to 69-year-old cohort.

Conclusion

As the population ages, cement augmentation is being considered as a treatment for vertebral compression fractures in increasingly older patients. These results suggest that even the very elderly may be appropriately considered for these procedures (level of evidence: 3).

Brain Structure and Function of Chronic Low Back Pain Patients on Long-Term Opioid Analgesic Treatment: A Preliminary Study

Chronic low back pain (CLBP) is often treated with opioid analgesics (OA), a class of medications associated with a significant risk of misuse. However, little is known about how treatment with OA affect the brain in chronic pain patients. Gaining this knowledge is a necessary first step towards understanding OA associated analgesia and elucidating long-term risk of OA misuse. Here we study CLBP patients chronically medicated with opioids without any evidence of misuse and compare them to CLBP patients not on opioids and to healthy controls using structural and functional brain imaging. CLBP patients medicated with OA showed loss of volume in the nucleus accumbens and thalamus, and an overall significant decrease in signal to noise ratio in their sub-cortical areas. Power spectral density analysis (PSD) of frequency content in the accumbens’ resting state activity revealed that both medicated and unmedicated patients showed loss of PSD within the slow-5 frequency band (0.01–0.027 Hz) while only CLBP patients on OA showed additional density loss within the slow-4 frequency band (0.027–0.073 Hz). We conclude that chronic treatment with OA is associated with altered brain structure and function within sensory limbic areas.

Long-Term Prospective Clinical And Radiographic Outcomes After Minimally Invasive Lateral Transiliac Sacroiliac Joint Fusion Using Triangular Titanium Implants

Background

Accumulating evidence supports the long-term safety and effectiveness of minimally invasive sacroiliac joint fusion (SIJF) for sacroiliac joint dysfunction.

Objective

To report 5-year clinical and radiographic follow-up in patients undergoing SIJF using triangular titanium implants (TTI).

Methods

One hundred and three subjects at 12 centers treated with SIJF using TTI in two prospective clinical trials (NCT01640353 and NCT01681004) were enrolled and followed in the current study (NCT02270203) with clinic visits at 3, 4 and 5 years. CT scans performed at 5 years were compared to prior CT scans (at 1 or 2 years) by an independent radiologist.

Results

Compared to baseline scores, SIJ pain scores at 5 years decreased by a mean of 54 points, disability scores (Oswestry Disability Index) decreased by 26 points, and quality of life scores (EuroQOL-5D time trade-off index) increased by 0.29 points (0–1 scale) (all p<0.0001). Satisfaction rates were high and the proportion of subjects taking opioids decreased from 77% at baseline to 41% at 5-year follow-up. Independent radiographic analysis showed a high rate (98%) of bone apposition to implants on both the sacral and iliac sides of the SI joint, with a high rate of bony bridging (87%) and a low rate of radiolucencies suggestive of loosening (5%).

Conclusion

A 5-year follow-up showed continued excellent clinical responses in patients with SIJ pain treated with SIJF using triangular titanium implants along with a high rate (88%) of joint fusion.

Level of evidence

Level II.

Long-term prospective outcomes after minimally invasive trans-iliac sacroiliac joint fusion using triangular titanium implants

Background

Minimally invasive sacroiliac joint fusion (SIJF) has become an increasingly accepted surgical option for chronic sacroiliac (SI) joint dysfunction, a prevalent cause of unremitting low back/buttock pain.

Objective

The objective of this study was to report clinical and functional outcomes of SIJF using triangular titanium implants (TTI) in the treatment of chronic SI joint dysfunction due to degenerative sacroiliitis or sacroiliac joint (SIJ) disruption at 3 years postoperatively.

Methods

A total of 103 subjects with SIJ dysfunction at 12 centers were treated with TTI in two prospective clinical trials (NCT01640353 and NCT01681004) and enrolled in this long-term follow-up study (NCT02270203). Subjects were evaluated in study clinics at study start and again at 3, 4, and 5 years.

Results

Mean (SD) preoperative SIJ pain score was 81.5, and mean preoperative Oswestry Disability Index (ODI) was 56.3. At 3 years, mean pain SIJ pain score decreased to 26.2 (a 55-point improvement from baseline, p<0.0001). At 3 years, mean ODI was 28.2 (a 28-point improvement from baseline, p<0.0001). In all, 82% of subjects were very satisfied with the procedure at 3 years. EuroQol-5D (EQ-5D) time trade-off index improved by 0.30 points (p<0.0001). No adverse events definitely related to the study device or procedure were reported; one subject underwent revision surgery at year 3.7. SIJ pain contralateral to the originally treated side occurred in 15 subjects of whom four underwent contralateral SIJF. The proportion of subjects who were employed outside the home full- or part-time at 3 years decreased somewhat from baseline (p=0.1814), and the proportion of subjects who would have the procedure again was lower at 3 years compared to earlier time points.

Conclusion

In long-term (3-year) follow-up, minimally invasive trans-iliac SIJF with TTI was associated with improved pain, disability, and quality of life with relatively high satisfaction rates.

Level of evidence

Level II.

Clinical relevance

SIJF with TTI.

Interspinous implants to treat spinal stenosis

PURPOSE OF REVIEW

Lumbar spinal stenosis has historically been treated with open decompressive surgery which is associated with significant morbidity and may give rise to various complications. Interspinous spacers (ISS) have been developed as a less invasive strategy which may serve to avoid many of these risks. The two current spacers that are FDA approved and commercially available are the Coflex and Superion devices. The goal is to review these two implants, their indications, and patient selection.

RECENT FINDINGS

The Coflex device has been shown to be analogous to decompression and fusion when treating moderate spinal stenosis. It provides dynamic stability after a decompression is performed, without the rigidity of pedicle-screw instrumentation. Recent results show improved outcomes in Coflex patients at 3 years of follow-up, as compared to decompression and fusion. The Superion implant is placed percutaneously in the interspinous space with minimal disruption of spinal anatomy. When compared to the X-Stop device (which is no longer available), the Superion implant shows improved outcomes at 3 years of follow-up. ISS are lesser invasive options as compared to formal decompression and fusion for the treatment of lumbar spinal stenosis.

Two-Year Outcomes from a Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion vs. Non-Surgical Management for Sacroiliac Joint Dysfunction

BACKGROUND

Sacroiliac joint (SIJ) dysfunction is an important and underappreciated cause of chronic low back pain.

OBJECTIVE

To prospectively and concurrently compare outcomes after surgical and non-surgical treatment for chronic SIJ dysfunction.

METHODS

One hundred and forty-eight subjects with SIJ dysfunction were randomly assigned to minimally invasive SIJ fusion with triangular titanium implants (SIJF, n = 102) or non-surgical management (NSM, n = 46). SIJ pain (measured with a 100-point visual analog scale, VAS), disability (measured with Oswestry Disability Index, ODI) and quality of life scores were collected at baseline and at scheduled visits to 24 months. Crossover from non-surgical to surgical care was allowed after the 6-month study visit was complete. Improvements in continuous measures were compared using repeated measures analysis of variance. The proportions of subjects with clinical improvement (SIJ pain improvement ≥20 points, ODI ≥15 points) and substantial clinical benefit (SIJ pain improvement ≥25 points or SIJ pain rating ≤35, ODI ≥18.8 points) were compared.

RESULTS

In the SIJF group, mean SIJ pain improved rapidly and was sustained (mean improvement of 55.4 points) at month 24. The 6-month mean change in the NSM group (12.2 points) was substantially smaller than that in the SIJF group (by 38.3 points, p<.0001 for superiority). By month 24, 83.1% and 82.0% received either clinical improvement or substantial clinical benefit in VAS SIJ pain score. Similarly, 68.2% and 65.9% had received clinical improvement or substantial clinical benefit in ODI score at month 24. In the NSM group, these proportions were <10% with non-surgical treatment only. Parallel changes were seen for EQ-5D and SF-36, with larger changes in the surgery group at 6 months compared to NSM. The rate of adverse events related to SIJF was low and only 3 subjects assigned to SIJF underwent revision surgery within the 24-month follow-up period.

CONCLUSIONS

In this Level 1 multicenter prospective randomized controlled trial, minimally invasive SIJF with triangular titanium implants provided larger improvements in pain, disability and quality of life compared to NSM. Improvements after SIJF persisted to 24 months. This study was approved by a local or central IRB before any subjects were enrolled. All patients provided study-specific informed consent prior to participation.

Randomized Controlled Trial of Minimally Invasive Sacroiliac Joint Fusion Using Triangular Titanium Implants vs Nonsurgical Management for Sacroiliac Joint Dysfunction: 12-Month Outcomes

Supplemental Digital Content is Available in the Text.

Sacroiliac joint (SIJ) dysfunction is a prevalent cause of chronic, unremitting lower back pain.

Does Level of Response to SI Joint Block Predict Response to SI Joint Fusion?

BACKGROUND

The degree of pain relief required to diagnose sacroiliac joint (SIJ) dysfunction following a diagnostic SIJ block (SIJB) is not known. No gold standard exists. Response to definitive (i.e., accepted as effective) treatment might be a reference standard.

METHODS

Subgroup analysis of 320 subjects enrolled in two prospective multicenter trials evaluating SIJ fusion (SIJF) in patients with SIJ dysfunction diagnosed by history, physical exam and standardized diagnostic SIJB. A 50% reduction in pain at 30 or 60 minutes following SIJB was considered confirmatory. The absolute and percentage improvements in Visual Analog Scale (VAS) SIJ pain and Oswestry Disability Index (ODI) scores at 6 and 12 months after SIJF were correlated with the average acute improvement in SIJ pain with SIJB.

RESULTS

The average pain reduction during the first hour after SIJB was 79.3%. Six months after SIJF, the overall mean VAS SIJ pain reduction was 50.9 points (0-100 scale) and the mean ODI reduction was 24.6 points. Reductions at 12 months after SIJF were similar. Examined in multiple ways, improvements in SIJ pain and ODI at 6 and 12 months did not correlate with SIJB findings.

CONCLUSIONS

The degree of pain improvement during SIJB did not predict improvements in pain or ODI scores after SIJF. A 50% SIJB threshold resulted in excellent post-SIJF responses. Using overly stringent selection criteria (i.e. 75%) to qualify patients for SIJF has no basis in evidence and would withhold a beneficial procedure from a substantial number of patients with SIJ dysfunction.

LEVEL OF EVIDENCE

Level 1.

CLINICAL RELEVANCE

The degree of pain improvement during an SIJ block does not predict the degree of pain improvement after SIJ fusion.

Superion(®) InterSpinous Spacer for treatment of moderate degenerative lumbar spinal stenosis: durable three-year results of a randomized controlled trial

PURPOSE

This report provides the 3-year clinical outcomes from the randomized, controlled US Food and Drug Administration Investigational Device Exemption trial of the Superion(®) for the treatment of moderate degenerative lumbar spinal stenosis.

PATIENTS AND METHODS

The Superion(®) was evaluated in the treatment of subjects aged 45 years or older suffering from symptoms of intermittent neurogenic claudication, secondary to a confirmed diagnosis of moderate degenerative lumbar spinal stenosis at one or two contiguous levels from L1 to L5. Patients were treated between June 2008 and December 2011 at 31 investigational sites. Three hundred ninety-one subjects were included in the randomized study group consisting of 190 Superion(®) and 201 X-STOP(®) control subjects. The primary composite endpoint was individual patient success based on four components: improvement in two of three domains of the Zurich Claudication Questionnaire, no reoperations at the index level, no major implant/procedure-related complications, and no clinically significant confounding treatments.

RESULTS

At 3 years, the proportion of subjects achieving the primary composite endpoint was greater for Superion(®) (63/120, 52.5%) than for X-STOP(®) (49/129, 38.0%) (P=0.023) and the corresponding success rates exceeded 80% for each of the individual components of the primary endpoint in the Superion(®) group (range: 81%-91%). Improvements in back and leg pain severity as well as back- and disease-specific functional outcomes were also maintained through 36 months.

CONCLUSION

The 3-year outcomes from this randomized controlled trial demonstrate durable clinical improvement consistently across all clinical outcomes for the Superion(®) in the treatment of patients with moderate degenerative lumbar spinal stenosis.

Two-year clinical outcomes of a multicenter randomized controlled trial comparing two interspinous spacers for treatment of moderate lumbar spinal stenosis

BACKGROUND

Interspinous spacers are a minimally invasive surgical alternative for patients with lumbar spinal stenosis (LSS) unresponsive to conservative care. The purpose of this prospective, multicenter, randomized, controlled trial was to compare 2-year clinical outcomes in patients with moderate LSS treated with the Superion(®) (Experimental) or the X-Stop(®), a FDA-approved interspinous spacer (Control).

METHODS

A total of 250 patients with moderate LSS unresponsive to conservative care were randomly allocated to treatment with the Experimental (n = 123) or Control (n = 127) interspinous spacer and followed through 2 years post-treatment. Complication data were available for all patients and patient-reported outcomes were available for 192 patients (101 Experimental, 91 Control) at 2 years.

RESULTS

Zurich Claudication Questionnaire (ZCQ) Symptom Severity and Physical Function scores improved 34% to 36% in both groups through 2 years (all p < 0.001). Patient Satisfaction scores at 2 years were 1.8 ± 0.9 with Experimental and 1.6 ± 0.8 with Control. Axial pain decreased from 59 ± 26 mm at baseline to 21 ± 26 mm at 2 years with Experimental and from 55 ± 26 mm to 21 ± 25 mm with Control (both p < 0.001). Extremity pain decreased from 67 ± 24 mm to 14 ± 22 mm at 2 years with Experimental and from 63 ± 24 mm to 18 ± 23 mm with Control (both p < 0.001). Back function assessed with the Oswestry Disability Index similarly improved with Experimental (37 ± 12% to 18 ± 16%) and Control (39 ± 12% to 20 ± 16%) (both p < 0.001). Freedom from reoperation at the index level was 84% for Experimental and 83% for Control (log-rank: p = 0.38) at 2 years.

CONCLUSIONS

Both interspinous spacers effectively alleviated pain and improved back function to a similar degree through 2 years in patients with moderate LSS who were unresponsive to conservative care.

TRIAL REGISTRATION

NCT00692276.

Recent advances in the prevention and management of complications associated with routine lumbar spine surgery

Lumbar spine surgery is often associated with complications in the perioperative and postoperative periods. Evidence-based literature in the prevention and management of adverse events, including surgical site infection, venous thromboembolism, and positioning-related complications, has advanced the understanding of the etiology of these complications and preventive measures. Cost-effective measures to reduce intraoperative bleeding can lead to a lower incidence of infection, disease transmission, and morbidity in the postoperative period. As the healthcare system receives additional scrutiny with value-based assessments, surgeons, hospitals, and administrators will need to make critical decisions to prevent and manage the complications of lumbar spine surgery.

Mitigating adverse event reporting bias in spine surgery

BACKGROUND

Recent articles in the lay press and literature have raised concerns about the ability to report honest adverse event data from industry-sponsored spine surgery studies. To address this, clinical trials may utilize an independent Clinical Events Committee (CEC) to review adverse events and readjudicate the severity and relatedness accordingly. We are aware of no prior study that has quantified either the degree to which investigator bias is present in adverse event reporting or the effect that an independent CEC has on mitigating this potential bias.

METHODS

The coflex Investigational Device Exemption study is a prospective randomized controlled trial comparing coflex (Paradigm Spine) stabilization with lumbar spinal fusion to treat spinal stenosis and spondylolisthesis. Investigators classified the severity of adverse events (mild, moderate, or severe) and their relationship to the surgery and device (unrelated, unlikely, possibly, probably, or definitely). An independent CEC, composed of three spine surgeons without affiliation to the study sponsor, reviewed and reclassified all adverse event reports submitted by the investigators.

RESULTS

The CEC reclassified the level of severity, relation to the surgery, and/or relation to the device in 394 (37.3%) of 1055 reported adverse events. The proportion of adverse events that underwent reclassification was similar in the coflex and fusion groups (37.9% compared with 36.0%, p = 0.56). The CEC was 5.3 (95% confidence interval [CI], 2.6 to 10.7) times more likely to upgrade than downgrade the adverse event. The CEC was 7.3 (95% CI, 5.1 to 10.6) times more likely to upgrade than downgrade the relationship to the surgery and 11.6 (95% CI, 7.5 to 18.8) times more likely to upgrade than downgrade the relationship to the device. The status of the investigator's financial interest in the company had little effect on the reclassification of adverse events.

CONCLUSIONS

Thirty-seven percent of adverse events were reclassified by the CEC; the large majority of the reclassifications were an upgrade in the level of severity or a designation of greater relatedness to the surgery or device.

CLINICAL RELEVANCE

An independent CEC can identify and mitigate potential inherent investigator bias and facilitate an accurate assessment of the safety profile of an investigational device, and a CEC should be considered a requisite component of future clinical trials.

Lumbar spinal stenosis

Lumbar spinal stenosis affects many patients and is one of the most common reasons for spinal surgery in the elderly population. New research and surgical innovations have resulted in a better understanding of the disease and its diagnosis and treatment. To select the optimal treatment approach for each patient, it is helpful to review patient presentations, diagnostic workups, surgical and nonsurgical treatment options, evidence-based outcomes, and the pathophysiology of lumbar spinal stenosis.

Oblique radiographs compared favorably with computed tomography images in assessing cervical foraminal area

Oblique radiographs are often ordered to evaluate the patency of cervical intervertebral foramina. Previous studies have shown that computed tomography (CT) provides accurate measurements of foraminal dimensions. Up until now, no study has directly compared the diagnostic utility of oblique radiographs and CT. We conducted a study to quantify the correlation between cervical foramina dimensions measured on oblique radiographs and on CT scans. Heights, widths, and cross-sectional areas were evaluated at every level from C2-C3 through C7-T1 using both oblique radiographs and oblique CT reconstructions. Both measurements were performed at a 50% oblique angle. Interreliability and intrareliability statistics for radiographs and CT were 0.91 and 0.99 for height, 0.90 and 0.97 for width, and 0.84 and 0.92 for area. Pearson correlation coefficients for height, width, and area were 0.439, 0.871, and 0.899, respectively. Oblique radiographs of the cervical spine provide accurate estimates of intervertebral foraminal dimensions--estimates similar to those generated from CT reconstructions. Thus, these radiographs may serve as an acceptable first-line imaging study for initial assessment of patients suspected of having nerve root compression that precludes the higher cost and radiation exposure associated with CT scans.

A novel technique for preparing an allograft fibula for use as a transsacral graft as treatment for high-grade spondylolisthesis

We describe a novel technique for preparing a fibular allograft for use as a transsacral strut with an anterior cruciate ligament (ACL) coring reamer for stabilization of high-grade spondylolisthesis deformities involving the L5--S1 segment in conjunction with instrumented posterolateral fusions. Over 4 years, 6 patients underwent instrumented posterolateral fusions from L3 or L4 to the sacrum or ileum plus posterior implantation of transsacral fibular allografts fashioned with an ACL coring reamer (Arthrex, Naples, Florida). No intraoperative complications were noted. At most recent follow-up (1-6 years), 5 of the patients reported no adverse events; the sixth patient reported prominent hardware, which was removed 5 years after the index surgery. ACL coring reamers seem to facilitate processing of fibular allografts so that they may be used as transsacral dowels for stabilizing high-grade L5--S1 spondylolisthesis deformities.

Pitfalls in the publication of scientific literature: a road map to manage conflict of interest and other ethical challenges

The process of publishing scientific research can be hampered by potential pitfalls for journals and researchers alike; the definition and determination of authorship, legal documentation, data accuracy, and disclosure of financial conflicts of interest are all examples. In the current article, the authors discuss the challenges related to scientific medical writing and provide updated recommendations for both the prevention and management of these issues.

Effects of recombinant human bone morphogenetic protein 2 on surgical infections in a rabbit posterolateral lumbar fusion model

Recombinant human bone morphogenetic proteins (rhBMPs) are often used during spine surgery, but their effects on postoperative infections have not been well elucidated. Long-bone studies suggest that BMPs may limit local infection and facilitate bone formation. Until now, rhBMP-2 had not been evaluated in the setting of infected spinal arthrodesis. In the study reported here, we evaluated the safety and efficacy of rhBMP-2 and autograft in inducing fusion in the setting of surgically acquired infection. Sixty rabbits underwent fusion with autograft or rhBMP-2 with coadministration of Staphylococcus aureus or sterile saline. In the noninoculated groups, 4/15 autograft and 13/13 rhBMP-2 rabbits fused (P<.001). In the inoculated groups, 0/14 autograft and 3/12 rhBMP-2 rabbits fused (P = .085). There were 4/14 early deaths caused by infection in the autograft group and 0/12 in the rhBMP-2 group (P = .1). Although the difference in fusion rates and early deaths from infection for rhBMP-2 and autograft did not reach our predetermined alpha error threshold, the data were trending toward significance. Our results demonstrated no increase in morbidity or mortality associated with use of rhBMP-2 in the setting of local infection. Although BMP use with infections remains controversial, these results indicate that rhBMP- 2 could be used in a contaminated environment.

Radiation exposure from musculoskeletal computerized tomographic scans

BACKGROUND

Computerized tomographic scans are routinely obtained to evaluate a number of musculoskeletal conditions. However, since computerized tomographic scans expose patients to the greatest amounts of radiation of all imaging modalities, the physician must be cognizant of the effective doses of radiation that are administered. This investigation was performed to quantify the effective doses of computerized tomographic scans that are performed for various musculoskeletal applications.

METHODS

The digital imaging archive of a single institution was retrospectively reviewed to identify helical computerized tomographic scans that were completed to visualize the extremities or spine. Imaging parameters were recorded for each examination, and dosimetry calculator software was used to calculate the effective dose values according to a modified protocol derived from publication SR250 of the National Radiological Protection Board of the United Kingdom. Computerized tomographic scans of the chest, abdomen, and pelvis were also collected, and the effective doses were compared with those reported by prior groups in order to validate the results of the current study.

RESULTS

The mean effective doses for computerized tomographic scans of the chest, abdomen, and pelvis (5.27, 4.95, and 4.85 mSv, respectively) were consistent with those of previous investigations. The highest mean effective doses were recorded for studies evaluating the spine (4.36, 17.99, and 19.15 mSv for the cervical, thoracic, and lumbar spines, respectively). In the upper extremity, the effective dose of a computerized tomographic scan of the shoulder (2.06 mSv) was higher than those of the elbow (0.14 mSv) and wrist (0.03 mSv). Similarly, the effective dose of a hip scan (3.09 mSv) was significantly higher than those observed with knee (0.16 mSv) and ankle (0.07 mSv) scans.

CONCLUSIONS

Computerized tomographic scans of the axial and appendicular skeleton are associated with substantially elevated radiation exposures, but the effective dose declines substantially for anatomic structures that are further away from the torso.

Thoracolumbar spine trauma classification: the Thoracolumbar Injury Classification and Severity Score system and case examples

OBJECT

The aim of this study was to review the Thoracolumbar Injury Classification and Severity Score (TLICS) and to demonstrate its application through a series of spine trauma cases.

METHODS

The Spine Trauma Study Group collaborated to create and report the TLICS system. The TLICS system is reviewed and applied to 3 cases of thoracolumbar spine trauma.

RESULTS

The TLICS system identifies 3 major injury characteristics to describe thoracolumbar spine injuries: injury morphology, posterior ligamentous complex integrity, and neurological status. In addition, minor injury characteristics such as injury level, confounding variables (such as ankylosing spondylitis), multiple injuries, and chest wall injuries are also identified. Each major characteristic is assigned a numerical score, weighted by severity of injury, which is then summated to yield the injury severity score. The TLICS system has demonstrated initial success and its use is increasing. Limitations of the TLICS system exist and, in some instances, have yet to be addressed. Despite these limitations, the severity score may provide a basis to judge spinal stability and the need for surgical intervention.

CONCLUSIONS

By addressing both the posterior ligamentous integrity and the patient's neurological status, the TLICS system attempts to overcome the limitations of prior thoracolumbar classification systems. The TLICS system has demonstrated both validity and reliability and has also been shown to be readily learned and incorporated into clinical practice.

Postoperative bracing after spine surgery for degenerative conditions: a questionnaire study

BACKGROUND CONTEXT

A variety of orthoses are routinely applied after spinal procedures but there are limited data regarding their efficacy, especially with the increasing use of internal fixation. At this time, the proper indications for postoperative bracing are not well established.

PURPOSE

To assess the postoperative bracing patterns of spine surgeons.

STUDY DESIGN/SETTING

Questionnaire study.

PATIENT SAMPLE

Spine surgeons attending the "Disorders of the Spine" conference (January 2008, Whistler, Canada).

OUTCOME MEASURES

Frequencies of bracing after specific surgical procedures.

METHODS

A single-page questionnaire was distributed to all spine surgeons attending the "Disorders of the Spine" conference (January 2008). The questionnaire focused on whether surgeons typically immobilize patients after specific spinal procedures, the type of orthosis used, the duration of treatment, and the rationale for bracing.

RESULTS

Ninety-eight of 118 surgeons completed the survey (response rate: 83%). The frequency of bracing was similar between academic and private as well as orthopedic and neurosurgical practices. The difference in the bracing tendencies of fellowship and non-fellowship trained surgeons was found to be statistically significant (61% vs. 46%, p<.0001). The duration of clinical experience did not appear to influence the propensity of surgeons to use orthoses. Bracing was employed more regularly after cervical spine procedures than surgeries involving the lumbar spine (63% vs. 49%, p<.0001). In the anterior cervical spine, orthoses were used more often as the complexity of the procedure increased from single to multilevel constructs (55% vs. 76%, p<.0001). The frequencies of bracing were not significantly different between noninstrumented and instrumented lumbar fusions. In most cases, bracing was continued for a total of 3-8 weeks and the restriction of patient activity was the most common reason cited by surgeons who use orthoses.

CONCLUSIONS

Although most of the respondents brace their patients postoperatively, there is an obvious lack of consensus regarding the most appropriate type, duration, and indications for immobilization. Further prospective, clinical studies may play a helpful role in evaluating the efficacy of postoperative bracing protocols.

Which regions of the operating gown should be considered most sterile?

Various guidelines have been proposed regarding which portions of a surgical gown may be considered sterile. Unfortunately, the validity of these recommendations has not been definitively established. We therefore evaluated gown sterility after major spinal surgery to assess the legitimacy of these guidelines. We used sterile culture swabs to obtain samples of gown fronts at 6-inch increments and at the elbow creases of 50 gowns at the end of 29 spinal operations. Another 50 gowns were swabbed immediately after they were applied to serve as negative controls. Bacterial growth was assessed using semiquantitative plating techniques on a nonselective, broad-spectrum media. Contamination was observed at all locations of the gown with rates ranging from 6% to 48%. Compared with the negative controls, the contamination rates were greater at levels 24 inches or less and 48 inches or more relative to the ground and at the elbow creases. The section between the chest and operative field had the lowest contamination rates. Based on these results, we consider the region between the chest and operative field to be the most sterile and any contact with the gown outside this area, including the elbow creases, should be avoided to reduce the risk of infection.

Acute cervical osteomyelitis and prevertebral abscess after routine tonsillectomy

BACKGROUND CONTEXT

Tonsillectomy is among the most commonly performed surgical procedures. The development of severe infection after tonsillectomy is a very rare but potentially fatal complication that has not been described in the orthopedic, neurosurgical, or spine literature.

PURPOSE

To present acute cervical osteomyelitis and prevertebral abscess formation as a complication of a routine tonsillectomy.

STUDY DESIGN

Case report, literature review.

METHODS

A case report was prepared on the clinical and radiographic data of a patient presenting with prevertebral abscess and acute cervical osteomyelitis 6 weeks after routine tonsillectomy. A review of relevant literature was additionally performed.

RESULTS

The patient presented 6 weeks after tonsillectomy with evidence of a deep cervical infection. Operative debridement with anterior and posterior surgical stabilization was performed. The patient completed a 6-week course of intravenous antibiotics. At 24-month follow-up, the patient showed no signs of infection and demonstrated a stable fusion mass.

CONCLUSIONS

The development of prevertebral abscess and acute cervical osteomyelitis has been discussed in a small number of otolaryngology case reports and has not been previously reported in the orthopedic, neurosurgical, or spine literature. Symptoms may be nonspecific, and so a high index of clinical suspicion is needed. Delay in treatment may lead to significant morbidity and even mortality. Successful treatment can be obtained through operative debridement and intravenous antibiotic therapy.

Sterility of C-arm fluoroscopy during spinal surgery

STUDY DESIGN

Prospective study evaluating the sterility of 25 C-arm drapes after their use during spine surgery.

OBJECTIVE

To use swab samples to evaluate the sterility of draped C-arms at the end of spine surgical cases and assess the integrity of the sterile technique.

SUMMARY OF BACKGROUND DATA

Intraoperative fluoroscopy is used routinely in the operating room for a variety of spinal applications. Although the C-arm may help the surgeon assess spinal alignment and facilitate the placement of instrumentation, there are concerns that the C-arm may represent a potential source of contamination and increase the risk of developing a postoperative infection. METHODS.: This study included 25 surgical cases requiring a standard fluoroscopic C-arm that were performed by 2 spine surgeons. Sterile culture swabs were used to obtain samples from 5 defined locations on the C-arm drape after its use during the operation. The undraped technician's console was sampled in each case as a positive control and an additional 25 C-arm drapes were swabbed immediately after they were applied to the C-arm unit in order to obtain negative controls. Swab samples were assessed for bacterial growth on 5% sheep blood Columbia agar plates using a semiquantitative technique.

RESULTS

Contamination was noted on only 1 of 25 negative control drapes at a single location (4%). One hundred percent and 96% of the positive control swabs that were obtained from the negative controls and postoperative drapes exhibited growth, respectively. Although at least some degree of contamination was observed at all locations of the C-arm drape after surgery, the upper 2 sample sites demonstrated the greatest degree of contamination; the incidences of postoperative contamination were significantly greater for the top (56%, P < 0.000001) and upper front of the receiver (28%, P = 0.010) compared to the negative controls. In contrast, the lower front, receiver plate, and midportion of the C-arm were associated with lower rates of contamination (12%-20%).

CONCLUSION

The upper portions of the C-arm clearly exhibited the greatest rates of contamination during spinal operations. This contamination most likely occurs when the undraped portions of the C-arm are rotated to acquire lateral images. As a result, we no longer consider the top portion of the C-arm drape to be sterile in these situations and we believe that avoiding contact with these areas may decrease the risks of intraoperative contamination and possibly postoperative infection as well.

The safety and efficacy of OP-1 (rhBMP-7) as a replacement for iliac crest autograft for posterolateral lumbar arthrodesis: minimum 4-year follow-up of a pilot study

BACKGROUND CONTEXT

Although autogenous bone is still considered to be the gold standard graft material for promoting spinal fusion, other bone graft substitutes have been developed in an attempt to improve arthrodesis rates and avoid the complications associated with the procurement of autograft. The bone morphogenetic proteins (BMPs) represent a family of osteoinductive growth factors that are known to stimulate the osteoblastic differentiation of stem cells. Osteogenic protein-1 (OP-1) Putty is a commercially available BMP preparation that is already approved for use in humans. Previous clinical studies involving patients with degenerative spondylolisthesis have reported that the efficacy and safety of OP-1 Putty is comparable to that of autograft at both 1- and 2-year follow-up.

PURPOSE

The purpose of this study was to evaluate the intermediate-term efficacy and safety of OP-1 Putty as an alternative to autogenous bone by comparing the 4-year radiographic, clinical, and safety data of these same patients who underwent decompression and uninstrumented fusion with either OP-1 Putty or iliac crest autograft.

STUDY DESIGN/SETTING

A prospective, randomized, controlled, multicenter clinical pilot study.

PATIENT SAMPLE

Thirty-six patients undergoing decompressive laminectomy and single-level uninstrumented fusion for degenerative spondylolisthesis and symptomatic spinal stenosis were randomized in a 2:1 fashion to receive either OP-1 Putty (24 patients) or autogenous iliac crest bone graft (12 patients).

OUTCOME MEASURES

Patient-reported outcome measures consisting of Oswestry Disability Index and Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) scores were used to evaluate clinical efficacy. Perioperative data including operative time, estimated blood loss, and duration of hospital stay were also recorded for each surgery. Postoperatively, a neurological examination and an assessment of donor-site pain (if applicable) were performed at every follow-up visit. Radiographic fusion success was defined as the presence of continuous bridging bone formation between the transverse processes at the level of the spondylolisthesis with minimal motion evident on dynamic lateral x-ray films. The primary efficacy endpoint was the overall success rate, a composite measure derived from both radiographic and clinical parameters. The safety of OP-1 Putty was confirmed by comparing the nature and frequency of all adverse events and complications that were prospectively observed in either of the groups.

METHODS

Thirty-six patients with degenerative spondylolisthesis and symptoms of neurogenic claudication underwent decompressive laminectomy and single-level uninstrumented fusion with either OP-1 Putty or autograft. All patients were evaluated at 6 weeks and 3, 6, 9, 12, and 24 months, after which time they were instructed to return on a yearly basis. Multiple neuroradiologists blinded to the assigned treatment reviewed static and dynamic X-ray films with digital calipers to assess fusion status according to the presence of continuous bridging bone across the transverse processes as well as the amount of residual motion evident at the level of interest. Oswestry Disability Index surveys and SF-36 questionnaires were used to assess clinical outcomes.

RESULTS

At the 48-month time point, complete radiographic and clinical data were available for 22 of 36 patients (16 OP-1 Putty and 6 autograft) and 25 of 36 patients (18 OP-1 Putty and 7 autograft), respectively. Radiographic evidence of a solid arthrodesis was present in 11 of 16 OP-1 Putty patients (68.8%) and 3 of 6 autograft patients (50%). Clinically successful outcomes defined as at least a 20% improvement in preoperative Oswestry scores were experienced by 14 of 19 OP-1 Putty patients (73.7%) and 4 of 7 autograft patients (57.1%); these clinical findings were corroborated by similar increases in SF-36 scores. The respective overall success rates of the OP-1 Putty and autograft group were 62.5% and 33.3%. In this study, there were no incidents of local or systemic toxicity, ectopic bone production, or other adverse events directly related to the use of OP-1 Putty.

CONCLUSION

Despite the challenges associated with obtaining a solid uninstrumented fusion in patients with degenerative spondylolisthesis, the rates of radiographic fusion, clinical improvement, and overall success associated with the use of OP-1 Putty were at least comparable to that of the autograft controls for at least 48 months after surgery. These results appear to validate the short-term results previously reported for OP-1 Putty and suggest that this material may potentially represent a viable bone graft substitute for certain fusion applications.

The influence of fracture mechanism and morphology on the reliability and validity of two novel thoracolumbar injury classification systems

STUDY DESIGN

The Thoracolumbar Injury Severity Score (TLISS) and the Thoracolumbar Injury Classification and Severity Score (TLICS) were prospectively evaluated.

OBJECTIVES

To compare the reliability and validity of the TLISS and TLICS schemes to determine the importance of injury mechanism and morphology to the identification and treatment of thoracolumbar fractures.

SUMMARY OF BACKGROUND DATA

Two novel algorithms have been developed for the categorization and management of thoracolumbar injuries: the TLISS system emphasizing injury mechanism and the TLICS scheme involving injury morphology.

METHODS

The clinical and radiographic findings of 25 patients with thoracolumbar fractures were prospectively presented to 5 groups of surgeons with disparate levels of training and experience with spinal trauma. These injuries were consecutively scored, first using the TLISS and then 3 months later with the TLICS. The recommended treatments proposed by the 2 schemes were compared with the actual management of each patient.

RESULTS

For both algorithms, the interrater kappa statistics of all subgroups (mechanism/morphology, status of the posterior ligaments, total score, predicted management) were within the range of moderate to substantial reproducibility (0.45-0.74), and there were no statistically significant differences noted between the respective kappa values. Interrater correlation was higher for the TLISS paradigm on mechanism/morphology, integrity of the posterior ligaments, and proposed management (P < or = 0.01). The TLISS and TLICS schemes both exhibited excellent overall validity.

CONCLUSIONS

Although both schemes were noted to have substantial reproducibility and validity, our results indicate the TLISS is more reliable than the TLICS, suggesting that the mechanism of trauma may be a more valuable parameter than fracture morphology for the classification and treatment thoracolumbar injuries. Since these injury characteristics are interrelated and are critical to the maintenance of spinal stability, we think that both concepts should be considered during the assessment and management of these patients.

The adoption of a new classification system: time-dependent variation in interobserver reliability of the thoracolumbar injury severity score classification system

STUDY DESIGN

Prospective clinical assessment of the interobserver reliability of the Thoracolumbar Injury Classification and Severity Score (TLISS) in a series of consecutive patients.

OBJECTIVE

To evaluate the time-dependent changes in interobserver reliability of the TLISS system.

SUMMARY OF BACKGROUND DATA

Reliability of an injury classification system is fundamental to its usefulness. A system that can be taught and implemented effectively will be highly reliable. Vaccaro et al recently introduced a novel thoracolumbar injury classification and treatment recommendation system called the "Thoracolumbar Injury Classification and Severity Score." An improvement over previous traumatic thoracolumbar systems, it has been designed to be both descriptive as well as prognostic. To define better the benefits of this system, the purpose of our study was to assess the time-dependent changes associated with implementation of the TLISS system at 1 institution.

METHODS

Seventy-one consecutive patients presenting with acute thoracolumbar injury were prospectively assessed at a single training institution. Plain radiographs, computed tomography, and magnetic resonance imaging were independently reviewed, and each case was classified according to the TLISS system. Seven months later, 25 consecutive patients presenting with acute thoracolumbar injuries were prospectively assessed at the same institution. TLISS classification criteria were again applied after reviewing plain radiographs, computed tomography, and magnetic resonance imaging. The unweighted Cohen kappa coefficient and Spearman correlation values were calculated to assess interobserver reliability at each assessment time. Interobserved reliability at the time of the first assessment was then compared with interobserver reliability from the second assessment.

RESULTS

Statistically significant (P < 0.05) improvements in interobserver reliability were observed. Both the unweighted Cohen kappa coefficient and Spearman correlation values increased across all comparable fields: TLISS subscores (mechanism of injury, posterior ligamentous complex), total TLISS, and TLISS management scores.

CONCLUSIONS

The significant improvements observed in interobserver reliability of the TLISS system suggest that the classification system can be taught effectively and be readily incorporated into daily practice. The strong correlation values obtained at the second assessment time suggest that the TLISS system may be reproducibly used to describe thoracolumbar injuries.

Evaluation of two novel thoracolumbar trauma classification systems

BACKGROUND

Despite numerous attempts at classifying thoracolumbar spinal injuries, there remains no consensus on a single unifying algorithm of management. The ideal system should provide diagnostic and prognostic information, exhibit adequate reliability and validity and be easily applicable to clinical practice. The purpose of this study is to assess the reliability and validity of two novel classification systems for thoracolumbar fractures - the Thoracolumbar Injury Severity Score (TLISS) and the Thoracolumbar Injury Classification and Severity Score (TLICS) - and also to discuss potential efforts towards research in the future. MATEREIALS AND METHODS: Seventy-one patients with thoracolumbar fractures were prospectively assessed by surgeons with different levels of training and experience (attending orthopedic surgeon, attending neurosurgeon, spine fellows, senior level and junior level residents) at a single institution. Plain radiographs, CT and MRI imaging were used to classify these injuries using the TLISS system. Seven months later, 25 consecutive injuries were prospectively assessed with the TLISS and TLICS systems. Unweighted Cohen's kappa coefficients and Spearman's correlation values were calculated to assess inter-observer reliability and validity at each point in time.

RESULTS

For both the TLISS and TLICS algorithms, the inter-rater kappa statistics for all of the subgroups demonstrated moderate-to-substantial reliability (0.45-0.74), although there were no significant differences among the shared subgroups. The kappa score of the TLISS system was greater than that of the TLICS system for injury mechanism/ morphology. Correlation values were also greater across all subgroups (P ≤0.01). Statistically significant improvements in TLISS inter-observer reliability were observed across all TLISS fields (P <0.05). The TLISS and TLICS schemes both demonstrated excellent validity.

CONCLUSION

The TLISS and TLICS scales both exhibited substantial reliability and validity. However, the TLISS system displayed greater inter-observer correlation than did the TLICS and demonstrated significant improvements in reliability over time.

The effects of RANK blockade and osteoclast depletion in a model of pure osteoblastic prostate cancer metastasis in bone

Adenocarcinoma of the prostate exhibits a clear propensity for bone and is associated with the formation of osteoblastic metastases. It has previously been suggested that osteoclast activity may be necessary for the development of these osteoblastic metastases based on data from lytic and mixed lytic-blastic tumors. Here we investigate the effects of complete in vivo osteoclast depletion via the blockade of receptor activator of NF:kappaB (RANK) on the establishment and progression of purely osteoblastic (LAPC-9 cells) bone lesions induced by human prostate cancer cells using a SCID mouse intratibial injection model. The subcutaneous administration of the RANK antagonist (15 mg/kg) RANK:Fc did not prevent the formation of purely osteoblastic lesions, indicating that osteoclasts may not be essential to the initial development of osteoblastic metastases. However, RANK:Fc protein appeared to inhibit the progression of established osteoblastic lesions, suggesting that osteoclasts may be involved in the subsequent growth of these tumors once they are already present. In contrast, RANK:Fc treatment effectively blocked the establishment and progression of purely osteolytic lesions formed by PC-3 cells, which served as a positive control. These results indicate that in vivo RANK blockade may not be effective for the prevention of osteoblastic metastasis but may potentially represent a novel therapy that limits the growth of established metastatic CaP lesions in bone.

Effects of the proteasome inhibitor bortezomib on osteolytic human prostate cancer cell metastases

Prostate adenocarcinoma is the most common malignancy diagnosed in males, and bone metastases remain a significant source of morbidity and mortality in this population. The ubiquitin-proteasome cascade is responsible for the degradation of intracellular proteins, and this pathway is thought to play an essential role in the development of malignancies by altering the levels of various proteins involved in the regulation of cell division. Proteasome inhibitors represent a class of chemotherapeutic agents that have been shown to inhibit tumor growth by a number of different mechanisms. Using a murine intratibial injection model, we examined the effects of the proteasome inhibitor bortezomib on the establishment and progression of osteolytic bone lesions induced by human CaP cells (PC-3 cell line). In this study, the intravenous administration of bortezomib (1 mg/kg) did not prevent the initial formation of osteolytic lesions but did appear to inhibit their growth in a time-dependent fashion. In contrast, bortezomib therapy effectively inhibited the establishment and progression of subcutaneous PC-3 tumors, which served as a positive control. These results suggest that proteasome inhibitors such as bortezomib may represent a novel adjunctive therapy for the treatment of osteolytic skeletal metastases, especially when treatment is initiated early during the disease process.

Osteoinductivity of commercially available demineralized bone matrix. Preparations in a spine fusion model

BACKGROUND

Although autogenous bone is the most widely used graft material for spinal fusion, demineralized bone matrix preparations are available as alternatives or supplements to autograft. They are prepared by acid extraction of most of the mineralized component, with retention of the collagen and noncollagenous proteins, including growth factors. Differences in allograft processing methods among suppliers might yield products with different osteoinductive activities. The purpose of this study was to compare the efficacy of three different commercially available demineralized bone matrix products for inducing spinal fusion in an athymic rat model.

METHODS

Sixty male athymic rats underwent spinal fusion and were divided into three groups of eighteen animals each. Group I received Grafton Putty; Group II, DBX Putty; and Group III, AlloMatrix Injectable Putty. A control group of six animals (Group IV) underwent decortication alone. Six animals from each of the three experimental groups were killed at each of three intervals (two, four, and eight weeks), and the six animals from the control group were killed at eight weeks. At each of the time-points, radiographic and histologic analysis and manual testing of the explanted spines were performed.

RESULTS

The spines in Group I demonstrated higher rates of radiographically evident fusion at eight weeks than did the spines in Group III or Group IV (p < 0.05). Manual testing of the spines at four weeks revealed variable fusion rates (five of six in Group I, two of six in Group II, and none of six in Group III). At eight weeks, all six spines in Group I, three of the six in Group II, and no spine in Group III or IV had fused. Histologic analysis of the spines in Groups I, II, and III demonstrated varying amounts of residual demineralized bone matrix and new bone formation. Group-I spines demonstrated the most new bone formation.

CONCLUSIONS

This study demonstrated differences in the osteoinductive potentials of commercially available demineralized bone matrices in this animal model.