Glenn R. Rechtine

The subaxial cervical spine injury classification system: a novel approach to recognize the importance of morphology, neurology, and integrity of the disco-ligamentous complex.

Study Design. The classification system was derived through a literature review and expert opinion of experienced spine surgeons. In addition, a multicenter reliability and validity study of the system was conducted on a collection of trauma cases. Objectives. To define a novel classification system for subaxial cervical spine trauma that conveys information about injury pattern, severity, treatment considerations, and prognosis. To evaluate reliability and validity of this system. Summary of Background Data. Classification of subaxial cervical spine injuries remains largely descriptive, lacking standardization and prognostic information. Methods. Clinical and radiographic variables encountered in subaxial cervical trauma were identified by a working section of the Spine Trauma Study Group. Significant limitations of existing systems were defined and addressed within the new system. This system, as well as the Harris and Ferguson & Allen systems, was applied by 20 spine surgeons to 11 cervical trauma cases. Six weekslater, the cases were randomly reordered and again scored. Interrater reliability, intrarater reliability, and validity were assessed. Results. Each of 3 main categories (injury morphology, disco-ligamentous complex, and neurologic status) identified as integrally important to injury classification was assigned a weighted score; the injury severity score was obtained by summing the scores from each category. Treatment options were assigned based on threshold values of the severity score. Interrater agreement as assessed by intraclass correlation coefficient of the DLC, morphology, and neurologic status scores was 0.49, 0.57, and 0.87, respectively. Intrarater agreement as assessed by intraclass correlation coefficient of the DLC, morphology, and neurologic status scores was 0.66, 0.75, and 0.90, respectively. Raters agreed with treatment recommendations of the algorithm in 93.3% of cases, suggesting high construct validity. The reliability compared favorably to the Harris and Ferguson & Allen systems. Conclusion. The Sub-axial Injury Classification and Severity Scale provides a comprehensive classification system for subaxial cervical trauma. Early validity and reliability data are encouraging.

Postoperative Wound Infection after Instrumentation of Thoracic and Lumbar Fractures

Objective To assess the risk of infection in trauma patients undergoing surgical intervention with instrumentation for thoracic and lumbar fractures. Data Sources A case series of 235 consecutive patients who sustained thoracic and lumbar fractures seen at Tampa General Hospital in Tampa, Florida between 1986 and 1997. Study Selection 117 patients of the 235 consecutive patients included in the case series underwent surgical intervention; of these patients, twelve were identified as having acute postoperative wound infections. Data Extraction Of those patients treated with operative decompression and internal fixation, the authors identified and studied those with an acute wound infection. These patients were analyzed for risk factors and infection management. Data Synthesis Twelve (10 percent) patients with acute postoperative wound infections were identified. These included nine deep and three superficial infections. This provides an overall infection rate of 10 percent (12 of 117). Of these, there were three infections in twenty-one patients undergoing anterior spinal procedures. Only two of the twelve patients had pure cultures of gram-positive organisms (2 Staphylococcus aureus). Cultures from eight (67 percent) patients showed multiple organisms. There was a significantly (P < 0.05) higher risk of infection in the patients with a complete neurologic injury 41 percent (7/17) as compared with those with no deficit or incomplete injuries 5.0 percent (5/100). Conclusions The overall risk of infection is higher in the trauma patient than in the elective surgery population. Those patients with a complete neurologic deficit are at a greater risk. Aggressive and early intervention can help contribute to a favorable outcome.

The influence of perioperative risk factors and therapeutic interventions on infection rates after spine surgery: a systematic review.

Study Design. Systematic review. Objective. The objectives of this systematic review were to determine the patient and perioperative risk factors that contribute to infections after spine surgery and to examine the level of evidence to support the use of therapeutic interventions to reduce infection rates. Summary of Background Data. Infection continues to be one of the most common and feared complications after spine surgery. As such, it is used as a sentinel event for quality assurance processes. It is clear that the causes of infections after spine surgery are multifactorial and numerous patient- and procedure-related factors have been proposed as contributory elements. In addition, numerous perioperative adjuncts have been suggested to reduce infection rates. Methods. A systematic review of the English-language literature (published between January 1990 and June 2009) was undertaken to identify articles examining risk factors associated with and adjunct treatment measures for preventing surgical-site infections. Two independent reviewers assessed the level of evidence quality using the Grading of Recommendations Assessment, Development, and Evaluation criteria, and disagreements were resolved by consensus. Results. Of the 127 articles identified, 32 met the criteria to undergo full-text review. Individual patient, operative, and perioperative variables have been identified that are associated with increased infection rates (i.e., older age, obesity, diabetes, malnutrition, higher American Society of Anesthesiologists score, posterior approaches, and blood transfusions) but these variables have not been combined to provide individual patient risks based on a composite of factors (e.g., risk stratification). Of the surgical adjuncts investigated, only irrigation with dilute betadine solution showed moderate support for reducing infection rates. Conclusion. It is clear that the causes of postoperative spinal site infections are multifactorial and related to a complex interplay of patient and procedural influences. Because of these complexities, for any individual and surgical procedure, predictable infection rates likely exist that do not extrapolate to 0. Although we have identified factors associated with increased infection rates, further studies will be required to allow multifactorial risk stratification for individual patients and to further investigate the use of therapeutic adjuncts.

Treatment of thoracolumbar trauma: comparison of complications of operative versus nonoperative treatment.

The complications from the acute hospital stays of 235 patients with unstable thoracolumbar fractures were reviewed and compared based on patients who underwent surgical stabilization and those treated with an aggressive nonoperative course of 6 weeks on a kinetic bed. Complications such as deep venous thromboses, pulmonary emboli, and decubitus occur in patients with spine trauma. The perception is that surgical intervention decreases such complications and allows for earlier mobilization. The authors sought to determine the actual rate of occurrence and compare the groups for surgical and nonoperative complications. Two hundred thirty-five charts were reviewed. One hundred seventeen patients were treated with surgical stabilization, and 118 patients were treated with a nonoperative course of 6 weeks on a kinetic bed. Complications were assessed from the medical record. There was no significant difference in the occurrence of decubitus, deep venous thromboses, pulmonary emboli, or mortality between the two groups. Deep wound infections occurred in 8% of the operative cases. The length of stay was 24 days longer in the nonoperative group. Both operative and nonoperative treatments of thoracolumbar fractures are viable alternatives. The complication rates are similar, with the exception of wound infection. The length of hospital stay is longer in the nonoperative group. The selection of treatment method remains a matter of controversy.

Patient and surgeon radiation exposure: Comparison of standard and mini-C-arm fluoroscopy

BACKGROUND Use of c-arm fluoroscopy is common in the operating room, outpatient clinic, and emergency department. Consequently, there is a concern regarding radiation exposure. Mini-c-arm fluoroscopes have gained popularity; however, few studies have quantified exposure during mini-c-arm imaging of a body part larger than a hand or wrist. The purpose of this study was to measure radiation exposure sustained by the patient and surgeon during the use of large and mini-c-arm fluoroscopy of an ankle specimen. METHODS Standard and mini-c-arm fluoroscopes were used to image a cadaver ankle specimen, which was suspended on an adjustable platform. Dosimeters were mounted at specific positions and angulations to detect direct and scatter radiation. Testing was conducted under various scenarios that altered the proximity of the specimen and the radiation source. We attempted to capture a range of exposure data under conditions ranging from a best to a worst-case scenario, as one may encounter in a procedural setting. RESULTS With all configurations tested, measurable exposure during use of the large-c-arm fluoroscope was considerably higher than that during use of the mini-c-arm fluoroscope. Patient and surgeon exposure was notably amplified when the specimen was positioned closer to the x-ray source. The exposure values that we measured during ankle fluoroscopy were consistently higher than the exposure values that have been recorded previously during hand or wrist imaging. CONCLUSIONS Exposure of the patient and surgeon to radiation depends on the tissue density and the shape of the imaged extremity. Elevated exposure levels can be expected when larger body parts are imaged or when the extremity is positioned closer to the x-ray source. When it is possible to satisfactorily image an extremity with use of the mini c-arm, it should be chosen over its larger counterpart.

Spine-board Transfer Techniques and the Unstable Cervical Spine

Study Design. A repeated-measures design using a cadaveric model was used in this preliminary investigation on the effectiveness of spine-board transfer techniques. Objectives. To compare the amount of angulation (flexion–extension) motion that results at the cervical spine during the execution of the log-roll maneuver and the lift-and-slide technique; and to examine how changes to the integrity of the cervical spine impacts the amount of motion generated during the transfer process. Summary of Background Data. Very little research has been performed to establish the efficacy of spine-board transfer techniques. Early studies have indicated that the log-roll maneuver may not be appropriate for transferring victims with thoracolumbar injuries. Also, there has not been a single study that has reported the impact of transfer techniques on the unstable cervical spine. This lack of data necessitated the present study. Methods. Four groups (with six participants each) were asked to execute the log-roll maneuver and the lift-and-slide technique on five cadavers. An electromagnetic motion analysis device was used to assess the amount of angulation motion generated at the C5–C6 segment during the execution of these transfer techniques. To examine how changes to the integrity of the cervical spine impacts the amount of motion that is produced during the transfer process, flexion–extension motion was assessed under various conditions: across a stable C5–C6 segment, after the creation of a posterior ligamentous injury, and after a complete segmental injury. Results. No significant differences in angulation motion were noted between transfer techniques. However, significant differences were noted between all three injury conditions. That is, as the severity of the injury increased, the average amount of angulation motion produced at the site of the lesion also increased, regardless of technique. Conclusion. The participants of this study were able to restrict flexion–extension motion equally well with thelog-roll maneuver as with the lift-and-slide technique. However, more research is needed to fully ascertain the effectiveness of spine-board transfer techniques.

Radiation Exposure Issues in Orthopaedics

The topic of radiation exposure for patients, physicians, and staff has become prominent in the lay press. It seems that every week another story about radiation safety makes the evening news. For physicians and surgeons, the largest radiation exposures involve fluoroscopy use with either fixed or mobile units. For patients, fluoroscopy (c-arm), computed tomography (CT), and nuclear medicine studies constitute the vast majority of exposures. The use of each of these modalities has grown dramatically with changes in the practice of medicine. C-arm use in orthopaedic surgery is increasing rapidly as surgery transitions to minimal-access surgery. With less direct visualization, surgery is being conducted with fluoroscopic guidance. When fluoroscopy is combined with a computer for navigation systems, radiation exposure sustained by surgeons can be reduced dramatically. This transition does not decrease the patients radiation dose, and in some instances it can increase it substantially1. CT scans have become accepted as commonplace. The rate of CT use is thirty times greater than it was twenty years ago, and the radiation exposure sustained by a patient can be dramatic2,3. Less than one-sixth of physicians receive any training in radiation safety4. One questionnaire study of physicians showed that 4% did not know that ultrasound did not involve ionizing radiation and 27% did not know that magnetic resonance imaging (MRI) did not involve radiation at all5. Approximately 90% of physicians underestimated the radiation exposure and risks from pediatric radiographs and CT scans4. A single pediatric abdominal CT scan exposes the patient to more radiation than the seventy-year exposure from living in the vicinity of the Chernobyl accident2. For a five-year-old patient who weighs 19 kg, a chest CT is the equivalent of 600 chest radiographs and a CT of the …

The efficacy of pedicle screw/plate fixation on lumbar/lumbosacral autogenous bone graft fusion in adult patients with degenerative spondylolisthesis.

A total of 18 patients with grade I or II degenerative spondylolisthesis fused three levels or fewer with autogenous bone graft were entered at three clinical sites. After 2 years, these patients were found to have a fusion rate of 89%. A statistical analysis of these results compared with those in the literature showed that patients with spondylolisthesis who underwent fusion with pedicle screw instrumentation were > 3 times more likely to fuse than comparable patients implanted without a pedicle screw/plate system. The pedicle screw/plate system used in this study was shown to be an effective method of facilitating lumbar or lumbosacral fusion with autogenous bone graft for adult patients with a primary indication of grade I or II degenerative spondylolisthesis.

Interobserver and Intraobserver Reliability of Maximum Canal Compromise and Spinal Cord Compression for Evaluation of Acute Traumatic Cervical Spinal Cord Injury

Study Design. Prospective, blinded validation study of an objective, quantitative measure to assess maximum canal compromise (MCC) and maximum spinal cord compression (MSCC) in individuals with acute cervical spinal cord injury (SCI). Objective. To examine the intraobserver and interobserver reliability of MCC and MSCC in individuals with acute traumatic cervical SCI. Summary of Background Data. To date, few quantitative reliable radiologic methods for assessing the extent of spinal cord compression in the setting of acute SCI have been reported. MCC and MSCC, as assessed on mid-sagittal CT and T2-weighted MR images, respectively, appear to have potential clinical and prognostic value. To date, the validation of these assessment tools has been limited to a small number of observers at a single institution. However, to date no study has focused on the reliability of these radiologic parameters among a large cohort of spine surgeons from North America and abroad. This type of validation is critical to allow the broader use of these outcome measures in research studies and in clinical practice. Methods. Mid-sagittal MRI and CT images of cervical spine were selected from 10 individuals with acute traumatic cervical SCI. A total of 28 spine surgeons independently estimated CT MCC, T1-weighted MRI MCC, and T2-weighted MRI MSCC on two occasions using a calibrated ruler. In the first round of measurements, the observers estimated the radiologic parameters using only written instructions. The second measurement set was obtained after an interactive teaching session on the methodology. The order of the images was altered for the second set of measurements. Results. Analysis using parametric and nonparametric statistics indicated high intraobserver reliability for CT MCC, T1-weighted MRI MCC, and T2-weighted MSCC with interclass correlation coefficients (ICCs) of 0.92, 0.95, and 0.97, respectively. The interobserver reliability for all three radiologic parameters was considered moderate with ICCs ranging from 0.35 to 0.56. Conclusion. Our results indicate that the intraobserver reliability for the MCC and MSCC was high. Although the interobserver reliability for all three radiologic parameters in the present study was below 0.75, the observed differences were small and largely accounted for by the limitations in the precision of the calibrated ruler. For cases with minimal cord compression, the measurement of canal stenosis (MCC) proved more accurate. In contrast, in cases with severe cord compression, the assessment of MSCC was more accurate. It is anticipated that the use of digital imaging technologies will further enhance the precision of these outcome measures.

Cervical Collars are Insufficient for Immobilizing an Unstable Cervical Spine Injury

BACKGROUND Cervical orthoses are commonly used for extrication, transportation, and definitive immobilization for cervical trauma patients. Various designs have been tested frequently in young, healthy individuals. To date, no one has reported the effectiveness of collar immobilization in the presence of an unstable mid-cervical spine. STUDY OBJECTIVES To determine the extent to which cervical orthoses immobilize the cervical spine in a cadaveric model with and without a spinal instability. METHODS This study used a repeated-measures design to quantify motion on multiple axes. Five lightly embalmed cadavers with no history of cervical pathology were used. An electromagnetic motion-tracking system captured segmental motion at C5-C6 while the spine was maneuvered through the range of motion in each plane. Testing was carried out in intact conditions after a global instability was created at C5-C6. Three collar conditions were tested: a one-piece extraction collar (Ambu Inc., Linthicum, MD), a two-piece collar (Aspen Sierra, Aspen Medical Products, Irvine, CA), and no collar. Gardner-Wells tongs were affixed to the skull and used to apply motion in flexion-extension, lateral bending, and rotation. Statistical analysis was carried out to evaluate the conditions: collar use by instability (3 × 2). RESULTS Neither the one- nor the two-piece collar was effective at significantly reducing segmental motion in the stable or unstable condition. There was dramatically more motion in the unstable state, as would be expected. CONCLUSION Although using a cervical collar is better than no immobilization, collars do not effectively reduce motion in an unstable cervical spine cadaver model. Further study is needed to develop other immobilization techniques that will adequately immobilize an injured, unstable cervical spine.