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Tobias Pitzen, Juay Seng Tan, Marcel F. Dvorak, Charles Fisher and Thomas Oxland

Object

To avoid the cost of bone graft substitutes and the morbidity of iliac crest bone graft retrieval, locally harvested vertebral body bone has been used to fill interbody cages. When marginal hypertrophic osteophytes are used, there is little impact on the adjacent vertebrae, but when cancellous bone is removed from the central part of the vertebral body, it is not clear how significantly this procedure weakens the vertebra. The objective of this study was to investigate the immediate mechanical response of the cervical spine after removing bone from the central vertebral body.

Methods

Fourteen cervical functional spinal units (FSUs) (mean age 73.3 years, range 63–90 years) were used. For each FSU, bone mineral density (BMD) was determined using lateral-view dual-energy x-ray absorptiometry studies. The FSUs were assigned to 1 of 2 groups (test group or control group) with an equal distribution of BMD. All specimens received a cage placed into the cleaned disc space. The specimens from the test group had a 5-mm-diameter bone plug removed from the vertebral bodies superior and inferior to the cage-fitted disc. The specimens were loaded in flexion-compression until failure via an eccentric compressive force at 0.25 mm/second.

Results

The yield compression strength was 1149 ± 523 N for the test group and 1647 ± 962 N for the control group (p = 0.25). The ultimate compression strength was 1699 ± 498 N for the test group and 2450 N ± 835 N for the control group (p = 0.06). Force at 4 mm displacement was 1064 N for the test group and 1574 N for the control group (p = 0.15). Displacement at yield compression strength was 4.4 mm for the test group and 4.2 mm for the control group (p = 0.78). There was no significant intergroup difference for any of the studied parameters.

Conclusions

There does not appear to be a significant early biomechanical weakening of adjacent vertebrae caused by aforementioned technique of local bone harvest.

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Marcel F. Dvorak, Michael G. Johnson, Michael Boyd, Garth Johnson, Brian K. Kwon and Charles G. Fisher

Object. The primary goal of this study was to describe the long-term health-related quality of life (HRQOL) outcomes in patients who have suffered Jefferson-type fractures. These outcomes were compared with matched normative HRQOL data and with the patient's perceptions of their HRQOL prior to the injury. Variables that potentially influence these HRQOL outcomes were analyzed.

No standardized outcome assessments have been published for patients who suffer these fractures; their outcomes have long thought to be excellent following treatment. Determining the optimal surrogate measure to represent preinjury HRQOL in trauma patients is difficult.

Methods. A retrospective review, radiographic analysis, and cross-sectional outcome assessment were performed. The Short Form (SF)—36 and the American Academy of Orthopaedic Surgeons/North American Spine Society (AAOS/NASS) outcome instruments were filled out by patients at final follow-up examination (follow-up period 75 months, range 19–198 months) to represent their current status as well as their perceptions of preinjury status.

In 34 patients, the SF-36 physical component score and the AAOS/NASS pain values were significantly lower than normative values. There was no significant difference between normative and preinjury values. Spence criteria greater than 7 mm and the presence of associated injuries predicted poorer outcome scores during the follow-up period.

Conclusions. Long-term follow-up examination of patients with Jefferson fractures indicated that patients' status does not return to the level of their perceived preinjury health status or that of normative population controls. Those with other injuries and significant osseous displacement (≥ 7 mm total) may experience poorer long-term outcomes. Limitations of the study included a relatively low (60%) response rate and the difficulties of identifying an appropriate baseline outcome in a trauma population with which the follow-up outcomes can be compared.

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Stephen P. Kingwell, Armin Curt and Marcel F. Dvorak

The purpose of this review was to describe the relevant factors that influence neurological outcomes in patients who sustain traumatic conus medullaris injuries (CMIs) and cauda equina injuries (CEIs). Despite the propensity for spinal trauma to affect the thoracolumbar spine, few studies have adequately characterized the outcomes of CMIs and CEIs. Typically the level of neural axis injury is inferred from the spinal level of injury or the presenting neurological picture because no study from the spinal literature has specifically evaluated the location of the conus medullaris with respect to the level of greatest canal compromise. Furthermore, the conus medullaris is known to have a small but important variable location based on the spinal level. Patients with a CMI will typically present with variable lowerextremity weakness, absent lower-limb reflexes, and saddle anesthesia. The development of a mixed upper motor neuron and lower motor neuron syndrome may occur in patients with CMIs, whereas a CEI is a pure lower motor neuron injury. Many treatment options exist and should be individualized. Posterior decompression and stabilization offers at least equivalent neurological outcomes as nonoperative or anterior approaches and has the additional benefits of surgeon familiarity, shorter hospital stays, earlier rehabilitation, and ease of nursing care. Overall, CEIs and CMIs have similar outcomes, which include ambulatory motor function and a variable persistence of bowel, bladder, and potentially sexual dysfunctions.

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Andrea M. Simmonds, Y. Raja Rampersaud, Marcel F. Dvorak, Nicolas Dea, Angela D. Melnyk and Charles G. Fisher

OBJECT

A range of surgical options exists for the treatment of degenerative lumbar spondylolisthesis (DLS). The chosen technique inherently depends on the stability of the DLS. Despite a substantial body of literature dedicated to the outcome analysis of numerous DLS procedures, no consensus has been reached on defining or classifying the disorder with respect to stability or the role that instability should play in a treatment algorithm. The purpose of this study was to define grades of stability and to develop a guide for deciding on the optimal approach in surgically managing patients with DLS.

METHODS

The authors conducted a qualitative systematic review of clinical or biomechanical analyses evaluating the stability of and surgical outcomes for DLS for the period from 1990 to 2013. Research focused on nondegenerative forms of spondylolisthesis or spinal stenosis without associated DLS was excluded. The primary extracted results were clinical and radiographic parameters indicative of DLS instability.

RESULTS

The following preoperative parameters are predictors of stability in DLS: restabilization signs (disc height loss, osteophyte formation, vertebral endplate sclerosis, and ligament ossification), no disc angle change or less than 3 mm of translation on dynamic radiographs, and the absence of low-back pain. The validity and magnitude of each parameter’s contribution can only be determined through appropriately powered prospective evaluation in the future. Identifying these parameters has allowed for the creation of a preliminary DLS instability classification (DSIC) scheme based on the preoperative assessment of DLS stability.

CONCLUSIONS

Spinal stability is an important factor to consider in the evaluation and treatment of patients with DLS. Qualitative assessment of the best available evidence revealed clinical and radiographic parameters for the creation of the DSIC, a decision aid to help surgeons develop a method of preoperative evaluation to better stratify DLS treatment options.

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Rowan Schouten, Peter Lewkonia, Vanessa K. Noonan, Marcel F. Dvorak and Charles G. Fisher

OBJECT

The aim of this study was to define the expected functional and health-related quality of life outcomes following common thoracolumbar injuries on the basis of consensus expert opinion and the best available literature. Patient expectations are primarily determined by the information provided by health care professionals, and these expectations have been shown to influence outcome in various medical and surgical conditions. This paper presents Part 2 of a multiphase study designed to investigate the impact of patient expectations on outcomes following spinal injury. Part 1 demonstrated substantial variability in the information surgeons are communicating to patients. Defining the expected outcomes following thoracolumbar injury would allow further analysis of this relationship and enable surgeons to more accurately and consistently inform patients.

METHODS

Expert opinion was assembled by distributing questionnaires comprising 4 cases representative of common thoracolumbar injuries to members of the Spine Trauma Study Group (STSG). The 4 cases included a thoracolumbar junction burst fracture treated nonoperatively or with posterior transpedicular instrumentation, a low lumbar (L-4) burst fracture treated nonoperatively, and a thoracolumbar junction flexion-distraction injury managed with posterior fusion. For each case, 5 questions about expected outcomes were posed. The questions related to the proportion of patients who are pain free, the proportion who have regained full range of motion, and the patients' recreational activity restrictions and personal care and social life limitations, all at 1 year following injury, as well as the timing of return to work and length of hospital stay. Responses were analyzed and combined with the results of a systematic literature review on the same injuries to define the expected outcomes.

RESULTS

The literature review identified 38 appropriate studies that met the preset inclusion criteria. Published data were available for all injuries, but not all outcomes were available for each type of injury. The survey was completed by 31 (57%) of 53 surgeons representing 24 trauma centers across North America (15), Europe (5), India (1), Mexico (1), Japan (1) and Israel (1). Consensus expert opinion supplemented the available literature and was used exclusively when published data were lacking.

For example, 1 year following cast or brace treatment of a thoracolumbar burst fracture, the expected outcomes include a 40% chance of being pain free, a 70% chance of regaining pre-injury range of motion, and an expected ability to participate in high-impact exercise and contact sport with no or minimal limitation. Consensus expert opinion predicts reemployment within 4–6 months. The length of inpatient stay averages 4–5 days.

CONCLUSIONS

This synthesis of the best available literature and consensus opinion of surgeons with extensive clinical experience in spine trauma reflects the optimal methodology for determining functional prognosis after thoracolumbar trauma. By providing consistent, accurate information surgeons will help patients develop realistic expectations and potentially optimize outcomes.

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Kenneth C. Thomas, Christopher S. Bailey, Marcel F. Dvorak, Brian Kwon and Charles Fisher

Object

Despite extensive published research on thoracolumbar burst fractures, controversy still surrounds which is the most appropriate treatment. The objective of this study was to evaluate the scientific literature on operative and nonoperative treatment of patients with thoracolumbar burst fractures and no neurological deficit.

Methods

In their search of the literature, the authors identified all possible relevant studies concerning thoracolumbar burst fracture without neurological deficit. Two independent observers performed study selection, methodological quality assessment, and data extraction in a blinded and objective manner for all papers identified during the search. In a synthesis of the literature, the authors obtained evidence for both operative and nonoperative treatments.

Conclusions

There is a lack of evidence demonstrating the superiority of one approach over the other as measured using generic and disease-specific health-related quality of life scales. There is no scientific evidence linking posttraumatic kyphosis to clinical outcomes. The authors found that there is a strong need for improved clinical research methodology to be applied to this patient population.

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Christian P. DiPaola, Nicolas Dea, Marcel F. Dvorak, Robert S. Lee, Dennis Hartig and Charles G. Fisher

Object

Conflict of interest (COI) as it applies to medical education and training has become a source of considerable interest, debate, and regulation in the last decade. Companies often pay surgeons as faculty for educational events and often sponsor and give financial support to major professional society meetings. Professional medical societies, industry, and legislators have attempted to regulate potential COI without consideration for public opinion. The practice of evidence-based medicine requires the inclusion of patient opinion along with best available evidence and expert opinion. The primary goal of this study was to assess the opinion of the general population regarding surgeon-industry COI for education-related events.

Methods

A Web-based survey was administered, with special emphasis on the surgeon's role in industry-sponsored education and support of professional societies. A survey was constructed to sample opinions on reimbursement, disclosure, and funding sources for educational events.

Results

There were 501 completed surveys available for analysis. More than 90% of respondents believed that industry funding for surgeons' tuition and travel for either industry-sponsored or professional society educational meetings would either not affect the quality of care delivered or would cause it to improve. Similar results were generated for opinions on surgeons being paid by industry to teach other surgeons. Moreover, the majority of respondents believed it was ethical or had no opinion if surgeons had such a relationship with industry. Respondents were also generally in favor of educational conferences for surgeons regardless of funding source. Disclosures of a surgeon-industry relationship, especially if it involves specific devices that may be used in their surgery, appears to be important to respondents.

Conclusions

The vast majority of respondents in this study do not believe that the quality of their care will be diminished due to industry funding of educational events, for surgeon tuition, and/or travel expenses. The results of this study should help form the basis of policy and continued efforts at surgeon-industry COI management.

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Christopher S. Bailey, Charles G. Fisher, Michael C. Boyd and Marcel F. S. Dvorak

✓ The purpose of this case report is to demonstrate that an en bloc resection with negative surgical margins can be successfully achieved in a case of a seemingly unresectable C-2 chordoma if appropriate preoperative staging and planning are performed. The management of chordomas is controversial and challenging because of their location and often large size at presentation. Because chordomas are malignant and will aggressively recur locally if intralesional resection is conducted, wide or true en bloc resection is generally recommended. The literature indicates, however, that surgeons are reluctant to perform wide or even marginal resections because of the lesion’s complex surrounding anatomy and the risk of significant neurological compromise when a tumor abuts the dura mater or neural tissues. In this report the authors outline the successful en bloc resection of a large C1–3 chordoma and discuss the importance of preoperative staging and planning.

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Charles G. Fisher, Christian P. DiPaola, Vanessa K. Noonan, Christopher Bailey and Marcel F. S. Dvorak

Object

The nature of physician-industry conflict of interest (COI) has become a source of considerable concern, but is often not discussed in the research setting. With reduced funding available from government and nonprofit sources, industry support has enthusiastically grown, but along with this comes the potential for COI that must be regulated. In this era of shared decision making in health care, society must have input into this regulation. The purpose of this study was to assess the opinions of a North American population sample on COI regarding industry-funded research and to analyze population subgroups for trends.

Methods

A survey was developed for face and content validity, underwent focus group evaluation for clarity and bias reduction, and was administered via the World Wide Web. Demographic and general survey results were summarized as a percentage for each answer, and subgroup analysis was done using logistic regression. Generalizability of the sample to the US population was also assessed.

Results

Of 541 surveys, 40 were excluded due to missing information, leaving 501 surveys for analysis. The sample population was composed of more females, was older, and was more educated than a representative cross-section of the American population. Respondents support multidisciplinary surgeon-industry COI regulation and trust doctors and their professional societies the most to head this effort. Respondents trust government officials and company representatives the least with respect to regulation of COI. Most respondents feel that industry-sponsored research can involve physicians and be both objective and beneficial to patients.

Conclusions

Most respondents in this study felt that surgeons should be involved in industry-sponsored research and that more research, regardless of funding source, will ultimately benefit patients. The majority of respondents distrust government or industry to regulate COI. The development of evidence-based treatment recommendations requires the inclusion of patient preference. The authors encourage regulatory bodies to follow suit and include society's perspective on regulation of COI in research.

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Bizhan Aarabi, Stuart Mirvis, Kathirkamanthan Shanmuganathan, Alexander R. Vaccaro, Cassandra J. Holmes, Noori Akhtar-Danesh, Michael G. Fehlings and Marcel F. Dvorak

Object

Facet joints are major stabilizers of cervical motion allowing for effortless and pain-free multidimensional cervical spine movements without significant linear or rotational translation, thus minimizing any chance for spinal cord or nerve root impingement. Unilateral, nondisplaced subaxial facet fractures do not meet the conventional criteria for spinal instability under physiological loads. Limited evidence indicates that even with no or minimal displacement, 20%–80% of these fractures fail nonoperative management. The risk factors for instability in isolated nondisplaced subaxial facet fractures remain uncertain. In this retrospective study of prospectively collected data, the authors attempted to identify the predictors of failure in the management of isolated, nondisplaced subaxial facet fractures admitted to their Level I trauma center over a 10-year period.

Methods

Demographic, clinical, imaging, and follow-up data for 25 patients with unilateral nondisplaced subaxial facet fractures who were managed surgically (n = 10) or nonoperatively (n = 15) were statistically analyzed.

Results

The mean age of the patients was 38 years, 19 were male, and 21 of the fractures were the result of either motor vehicle accidents or falls. The mean motor score on the American Spinal Injury Association scale was 99.2, and the mean Subaxial Injury Classification (SLIC) severity score was 3 (operated 3.5, nonoperated 2.3). Allen mechanistic classification included 22 compressive-extension Stage 1 and 2 distractive-extension Stage 1 fractures. Subaxial facet fractures involved C-7 in 17 patients (68%), C-6 in 7 (28%), and C-3 in 1 (4%). The anatomical plane of fracture through the lateral mass was sagittal in 12 patients, axial in 8, and coronal in 3 patients. Nondisplaced floating lateral mass injuries were noted in 2 patients. The mean instability score, considering 7 components of the discoligamentous complex on MRI, was 3.2 (operated 3.6, nonoperated 3.0). Ten (40%) of 25 patients in this investigation did not have successful management, 9 in the nonoperated and 1 in the operated group (p = 0.018). Unsuccessful management was significantly greater in younger patients (p = 0.0008), possibly indicating selection bias (p = 0.07, Wilcoxon ranksum test). Fracture plane, instability, and SLIC scores did not play a significant role in treatment failure in this study.

Conclusions

In this study, surgery was superior to nonoperative management of isolated, nondisplaced, or minimally displaced subaxial cervical spine facet fractures.