Peter G. Whang

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.

Normal functional range of motion of the cervical spine during 15 activities of daily living.

Study Design Prospective clinical study. Objective The purpose of this investigation was to quantify normal cervical range of motion (ROM) and compare these results to those used to perform 15 simulated activities of daily living (ADLs) in asymptomatic subjects. Summary of Background Data Previous studies looking at cervical ROM during ADLs have been limited and used measuring devices that do not record continuous motion. The purpose of this investigation was to quantify normal cervical ROM and compare these results with those used to perform 15 simulated ADLs in asymptomatic subjects. Methods A noninvasive electrogoniometer and torsiometer were used to measure the ROM of the cervical spine. The accuracy and reliability of the devices were confirmed by comparing the ROM values acquired from dynamic flexion/extension and lateral bending radiographs to those provided by the device, which was activated while the radiographs were obtained. Intraobserver reliability was established by calculating the intraclass correlation coefficient for repeated measurements on the same subjects by 1 investigator on consecutive days. These tools were employed in a clinical laboratory setting to evaluate the full active ROM of the cervical spines (ie, flexion/extension, lateral bending, and axial rotation) of 60 asymptomatic subjects (30 females and 30 males; age, 20 to 75 y) as well as to assess the functional ROM required to complete 15 simulated ADLs. Results When compared with radiographic measurements, the electrogoniometer was found to be accurate within 2.3±2.2 degrees (mean±SD) and the intraobserver reliabilities for measuring the full active and functional ROM were both excellent (intraclass correlation coefficient of 0.96 and 0.92, respectively). The absolute ROM and percentage of full active cervical spinal ROM used during the 15 ADLs was 13 to 32 degrees and 15% to 32% (median, 20 degrees/19%) for flexion/extension, 9 to 21 degrees and 11% to 27% (14 degrees/18%) for lateral bending, and 13 to 57 degrees and 12% to 92% (18 degrees/19%) for rotation. Backing up a car required the most ROM of all the ADLs, involving 32% of sagittal, 26% of lateral, and 92% of rotational motion. In general, personal hygiene ADLs such as washing hands and hair, shaving, and applying make-up entailed a significantly greater ROM relative to locomotive ADLs including walking and traveling up and down a set of stairs (P<0.0001); in addition, compared with climbing up these steps, significantly more sagittal and rotational motion was used when descending stairs (P=0.003 and P=0.016, respectively). When picking up an object from the ground, a squatting technique required a lower percentage of lateral and rotational ROM than bending at the waist (P=0.002 and P<0.0001). Conclusions By quantifying the amounts of cervical motion required to execute a series of simulated ADLs, this study indicates that most individuals use a relatively small percentage of their full active ROM when performing such activities. These findings provide baseline data which may allow clinicians to accurately assess preoperative impairment and postsurgical outcomes.

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.

The management of spinal injuries in patients with ankylosing spondylitis or diffuse idiopathic skeletal hyperostosis: a comparison of treatment methods and clinical outcomes.

Study Design A retrospective review of 12 patients with ankylosing spondylitis (AS) and 18 patients with diffuse idiopathic skeletal hyperostosis (DISH) treated at a single institution for spinal injuries between the years 2000 and 2006. Objective To independently evaluate patients with these diagnoses who sustained spinal injuries and directly compare their treatment methods and clinical outcomes. Summary of Background Data AS and DISH are disorders characterized by abnormal ossification of the spinal column, which predisposes these patients to spinal injuries with potentially devastating consequences. Methods Patient and surgical data were obtained from medical records and appropriate imaging studies. Neurologic status was recorded using the American Spinal Injury Association (ASIA) impairment scale for spinal cord injuries, and clinical outcomes were assessed using Odom criteria. Results Most of these injuries involved the subaxial cervical spine between C5 and C7. In all, 41.2% of AS patients were considered to be ASIA A, whereas 44.4% of DISH patients were classified as ASIA E. Surgery was performed in 83.3% of AS patients and 66.7% of DISH patients, and the overall complication rates were 41.7% and 33.3%, respectively. There were no statistically significant differences between the survivorship and outcomes of the AS and DISH groups and 81.3% of all respondents were classified as having excellent or good outcomes. There were 4 deaths, all of which were considered to be related to the use of halo-vest immobilization. Conclusions Although the rate of neurologic injury was high for both groups, AS patients were more likely to exhibit neurologic deficits and undergo operative management. Although the majority of these spinal injuries were treated surgically, stable fractures without any associated neurologic deficits were often successfully managed with immobilization. Complications were observed with both operative and nonoperative treatments, although all of the deaths occurred in conjunction with the use of the halo-vest orthosis.

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 patients 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.

The radiation exposure associated with cervical and lumbar spine radiographs.

Study design Cross-sectional study. Objective To calculate the effective radiation doses of routine anteroposterior (AP) and lateral radiographs of the cervical and lumbar spines. Summary of Background Data Although plain radiographs are generally used as the initial imaging modality for the evaluation of patients with spinal complaints, the radiation that patients receive during these studies has not been well quantified. The effective radiation dose represents a functional measure of exposure that takes into account the amount of radiation delivered and the radiosensitivity of the exposed organs. Consequently, the effective dose is important to consider from a radiation safety perspective. Methods The imaging practices of our radiology department were reviewed and the effective radiation doses for AP and lateral radiographs of the cervical and lumbar spines were calculated using the following variables: emitted radiation dose, source-to-object distance [SOD], film area, and patient tissue dimensions. Values were obtained from both direct measurements and an examination of the established protocols employed at our institution. Results The effective doses for AP and lateral cervical radiographs were 0.12 and 0.02 mSv, respectively, whereas the corresponding values for AP and lateral lumbar films were much larger (2.20 and 1.50 mSv, respectively). For comparative purposes, a typical chest x-ray results in a radiation dose between 0.06 and 0.25 mSv. Conclusions In this investigation, cervical spine films gave rise to radiation doses that are similar to those of chest x-rays. However, lumbar spine radiographs generated effective radiation doses that were approximately an order of magnitude greater than these other studies. In both the cervical and lumbar regions, AP views resulted in significantly greater radiation exposure than corresponding lateral images. The effective radiation doses reported here may prove to be valuable for assessing the relative risks and benefits of spine radiographs to establish appropriate guidelines for their use.

Complications associated with the use of the recombinant human bone morphogenetic proteins for posterior interbody fusions of the lumbar spine

Study Design. Systematic review. Objective. The objectives of this review are to examine the spectrum of complications that have been reported in the literature after posterior interbody fusions of the lumbar spine augmented with bone morphogenetic proteins (BMPs) and discuss potential methods for their prevention. Summary of Background Data. The use of BMPs for spinal arthrodesis procedures has increased dramatically during the past decade. These products are commonly used in “off-label” fashion in posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) constructs. Recently, a number of adverse events have been attributed to the use of BMP for PLIF and TLIF surgical procedure, including heterotopic ossification within the epidural space or neuroforamina, postoperative radiculitis, and endplate osteolysis with interbody device subsidence. Methods. A computer aided literature search was performed on the electronic databases PubMed, MEDLINE, EMBASE, CINAHL, and Cochrane Database of Systematic Reviews. Key words of interest included BMPs, PLIF, TLIF, complications, heterotopic ossification, radiculitis, and osteolysis. All articles, in the English language, between 1990 and 2011 were considered relating to the use of BMPs in PLIF and TLIF constructs. Results. Seventeen articles discussing the use and potential complications of BMPs in PLIF and TLIF constructs were identified and reviewed. The studies were in the range of a level I prospective randomized trial to case reports of complications. There is a wide variation of published complications associated with BMP-augmented PLIF and TLIF constructs. Conclusion. Despite high fusion rates there is a growing body of evidence that the use of BMP in PLIF and TLIF constructs does not come without potential complication. There are appreciable rates of BMP-specific complications, which include heterotopic ossification within the epidural space or neuroforamina, postoperative radiculitis, and endplate osteolysis with interbody device subsidence. Level of Evidence: 2

Sacroiliac Joint Fusion Using Triangular Titanium Implants vs. Non-Surgical Management: Six-Month Outcomes from a Prospective Randomized Controlled Trial

Background Sacroiliac (SI) joint pain is a prevalent, underdiagnosed cause of lower back pain. SI joint fusion can relieve pain and improve quality of life in patients who have failed nonoperative care. To date, no study has concurrently compared surgical and non-surgical treatments for chronic SI joint dysfunction. Methods We conducted a prospective randomized controlled trial of 148 subjects with SI joint dysfunction due to degenerative sacroiliitis or sacroiliac joint disruptions who were assigned to either minimally invasive SI joint fusion with triangular titanium implants (N=102) or non-surgical management (NSM, n=46). SI joint pain scores, Oswestry Disability Index (ODI), Short-Form 36 (SF-36) and EuroQol-5D (EQ-5D) were collected at baseline and at 1, 3 and 6 months after treatment commencement. Six-month success rates, defined as the proportion of treated subjects with a 20-mm improvement in SI joint pain in the absence of severe device-related or neurologic SI joint-related adverse events or surgical revision, were compared using Bayesian methods. Results Subjects (mean age 51, 70% women) were highly debilitated at baseline (mean SI joint VAS pain score 82, mean ODI score 62). Six-month follow-up was obtained in 97.3%. By 6 months, success rates were 81.4% in the surgical group vs. 23.9% in the NSM group (difference of 56.6%, 95% posterior credible interval 41.4-70.0%, posterior probability of superiority >0.999). Clinically important (≥15 point) ODI improvement at 6 months occurred in 75% of surgery subjects vs. 27.3% of NSM subjects. At six months, quality of life improved more in the surgery group and satisfaction rates were high. The mean number of adverse events in the first six months was slightly higher in the surgical group compared to the non-surgical group (1.3 vs. 1.0 events per subject, p=0.1857). Conclusions Six-month follow-up from this level 1 study showed that minimally invasive SI joint fusion using triangular titanium implants was more effective than non-surgical management in relieving pain, improving function and improving quality of life in patients with SI joint dysfunction due to degenerative sacroiliitis or SI joint disruptions. Clinical relevance Minimally invasive SI joint fusion is an acceptable option for patients with chronic SI joint dysfunction due to degenerative sacroiliitis and sacroiliac joint disruptions unresponsive to non-surgical treatments.

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

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Evidence-based recommendations for spine surgery

Lumbar spinal imaging is commonly utilized in the evaluation of low back pain. The rationale for imaging, either plain radiographs, computed tomography (CT), or magnetic resonance imaging (MRI), is primarily based on identifying anatomical sources of pain. Unfortunately, the correlation between findings on imaging and clinical symptoms can be limited. A number of studies have been preformed to elucidate the value of spinal imaging in the setting of acute back pain. The definition of “value”, however, varies from study to study. Investigations have focused separately on diagnostic information, treatment interventions, patient outcomes, or patient satisfaction. Additionally, the inclusion and exclusion criteria for these studies have not been uniform. Specifically the definition of “red flags” for serious disease (fevers, weight loss, neurological deficits, etc.) are subjective and, in some instances, not defined. Nonetheless the clinical question remains: is immediate routine lumbar spine imaging more effective than usual care without imaging in patients with low back pain and no suggestion of “red flags.” Chou et al. used methods of systematic review and meta-analysis to address this question.