Percutaneous pedicle screw fixation for lumbar posterolateral instrumented fusion is an attractive alternative to standard open techniques. The technical aspects of this procedure can be challenging and even frustrating when first learning the technique. However, once these techniques have been mastered, they offer a safe, less invasive, less traumatic, more aesthetic method for performing fusion. The authors have outlined a step-by-step method for performing this surgery, and include a case series that demonstrates excellent results in patients treated with this procedure.
Eric B. Harris, Patrick Massey, James Lawrence, Jeffrey Rihn, Alex Vaccaro and D. Greg Anderson
Report of 2 cases
Joseph Hong, James A. Sanfilippo, Jeffrey Rihn, Carmella Fernandez, Corbett D. Winegar, Brian Friel, Steven Ludwig, Daniel Gelb and Alexander R. Vaccaro
Charcot spinal arthropathy is a relatively rare, destructive process characterized by a cycle of progressive deformity, destruction, and worsening instability as a result of repetitive trauma and inflammation. It may result from nontraumatic as well as traumatic causes. Historically, patients with severe symptomatic instability have been successfully treated with combined anterior and posterior fusion techniques. The long-term outcomes and potential complications, however, have not been well reported. The authors report on 2 such cases of Charcot spinal arthropathy treated surgically, one with a traumatic and one with a nontraumatic etiology. They include the unique pitfalls encountered while treating these patients, as well as their surgical treatments, complications, and long-term results.
Jeffrey A. Rihn, Nuo Yang, Charles Fisher, Davor Saravanja, Harvey Smith, William B. Morrison, James Harrop and Alexander R. Vacaro
Magnetic resonance imaging has been proposed as a powerful technique for assessing the integrity of the posterior ligamentous complex (PLC) in spinal trauma. Because MR imaging is often used to determine appropriate treatment, it is important to determine the accuracy and reliability of MR imaging in diagnosing PLC disruption. The purpose of this study is to compare the ability of the radiologist and surgeon to assess disruption of the PLC in the setting of acute cervical and thoracolumbar trauma using MR imaging.
The components of the PLC in 89 consecutive patients with cervical or thoracolumbar fractures following acute spinal trauma were evaluated using MR imaging by both a musculoskeletal radiologist and an independent spine surgeon and assessed intraoperatively under direct visualization by the treating surgeon. The MR imaging interpretations of the musculoskeletal radiologist and surgeon were compared with the intraoperative report for accuracy, sensitivity, specificity, and positive and negative predictive values. A comparison between the radiologist's and spine surgeon's accuracy of MR imaging interpretation was performed.
The agreement between both the spine surgeon's and radiologist's MR imaging interpretation and the actual intraoperative findings was moderate for most components of the PLC. Overall, the MR imaging interpretation of the surgeon was more accurate than that of the radiologist. The interpretation of MR imaging by the surgeon had negative predictive value and sensitivity of up to 100%. However, the specificity of MR imaging for both the surgeon and radiologist was lower, ranging from 51.5 to 80.5%.
Comparison of the MR imaging interpretations between surgeon and radiologist indicates that the surgeon was more accurate for some PLC components. The relatively low positive predictive value and specificity for MR imaging in assessing PLC integrity suggests that both the surgeon and radiologist tend to overdiagnose PLC injury using MR imaging. This can lead to unnecessary surgeries if only MR imaging is used for treatment decision making.
D. Greg Anderson, Worawat Limthongkul, Amirali Sayadipour, Christopher K. Kepler, James S. Harrop, Mitchell Maltenfort, Alexander R. Vaccaro, Alan Hilibrand, Jeffrey A. Rihn and Todd J. Albert
Lumbar degenerative spondylolisthesis (LDS) is common and has generally been characterized as a homogeneous disease entity in the literature and in clinical practice. Because disease variability has not been carefully characterized, stratification of treatment recommendations based on scientific evidence is currently lacking. In this study, the authors analyzed radiographic parameters of patients with LDS at the L4–5 level to better characterize this entity.
Demographic data were collected from 304 patients (200 women and 104 men) with LDS at the L4–5 level. Plain radiographs including anteroposterior, lateral, and flexion-extension lateral radiographs were analyzed for disc height, segmental angulation, segmental translation, and osteophyte formation. Correlations were sought between the variables of age, sex, disc height, segmental angulation, segmental translation, and osteophyte formation.
The mean patient age was 63.8 years (range 40–86 years). The mean mid-disc height was 7 mm (range 0–14 mm) on the neutral lateral view. The mean angulation between the superior endplate of L-5 and the inferior endplate of L-4 was 6° of lordosis (range 13° of kyphosis to 23° lordosis) on the neutral lateral view. The mean angular change between flexion and extension lateral radiographs was 5° (range 0°–17°). The mean translation on the neutral lateral view was 6 mm (range 0–15 mm). The mean change in translational between flexion and extension was 2 mm (range 0–11 mm). Twenty patients (7%) exhibited spondylolisthesis only on the flexion view. A significant positive correlation was found between the change in angulation and the change in translation on flexion and extension views (ρ = 0.18, p = 0.001). No significant correlation was found between anterior osteophyte size and mobility with flexion-extension radiographs.
The wide range in all radiographic parameters for LDS confirms the heterogeneous nature of this condition and suggests that a grading system to subclassify LDS may be clinically useful. On flexion and extension radiographs, increased translational motion correlated with increased angular motion. Anterior osteophyte size was not found to be predictive of segmental stability. This data set should prove beneficial to those seeking to subcategorize LDS in the future.
Kristen Radcliff, Christopher K. Kepler, Todd A. Rubin, Motasem Maaieh, Alan S. Hilibrand, James Harrop, Jeffrey A. Rihn, Todd J. Albert and Alexander R. Vaccaro
The load-sharing score (LSS) of vertebral body comminution is predictive of results after short-segment posterior instrumentation of thoracolumbar burst fractures. Some authors have posited that an LSS > 6 is predictive of neurological injury, ligamentous injury, and the need for surgical intervention. However, the authors of the present study hypothesized that the LSS does not predict ligamentous or neurological injury.
The prospectively collected spinal cord injury database from a single institution was queried for thoracolumbar burst fractures. Study inclusion criteria were acute (< 24 hours) burst fractures between T-10 and L-2 with preoperative CT and MRI. Flexion-distraction injuries and pathological fractures were excluded. Four experienced spine surgeons determined the LSS and posterior ligamentous complex (PLC) integrity. Neurological status was assessed from a review of the medical records.
Forty-four patients were included in the study. There were 4 patients for whom all observers assigned an LSS > 6, recommending operative treatment. Eleven patients had LSSs ≤ 6 across all observers, suggesting that nonoperative treatment would be appropriate. There was moderate interobserver agreement (0.43) for the overall LSS and fair agreement (0.24) for an LSS > 6. Correlations between the LSS and the PLC score averaged 0.18 across all observers (range −0.02 to 0.34, p value range 0.02–0.89). Correlations between the LSS and the American Spinal Injury Association motor score averaged −0.12 across all observers (range −0.25 to −0.03, p value range 0.1–0.87). Correlations describing the relationship between an LSS > 6 and the treating physician's decision to operate averaged 0.17 across all observers (range 0.11–0.24, p value range 0.12–0.47).
The LSS does not uniformly correlate with the PLC injury, neurological status, or empirical clinical decision making. The LSSs of only one observer correlated significantly with PLC injury. There were no significant correlations between the LSS as determined by any observer and neurological status or clinical decision making.