Balkan Cakir

Cervical pedicle screws: conventional versus computer-assisted placement of cannulated screws.

Study Design. Prospective clinical study with postoperative radiologic control of pedicle screw placement in the cervical spine. Objectives. To evaluate whether cervical pedicle screws can be placed safely in a conventional technique when using cannulated screws and separate stab incisions. Also, to evaluate if accuracy and safety of pedicle screw placement can be improved using a computer-assisted surgery (CAS) system (VectorVision®; BrainLAB AG, Heimstetten, Germany). Summary of Background Data. Pedicle screws are rarely used in the cervical spine compared to the use in lumbar and thoracic spine. The main reason is probably the potential risk of iatrogenic damage to the spinal cord, nerve roots, or vertebral artery caused by screw misplacement as well as the more demanding technique of pedicle screw placement in the cervical spine. Methods. A total of 52 consecutive patients with posterior cervical or cervicothoracic instrumentations using pedicle screws were evaluated prospectively. For the first 20 patients, 93 pedicle screws were implanted using the conventional technique with the image intensifier in the lateral view, and for the next 32 patients (167 screws), a CAS system was additionally used. For registration of the vertebra, surface-matching algorithms were used. For evaluation of screw placement, postoperative computerized tomography with multiplanar reconstructions in the screw axis was performed for each screw. Results. No implant-related complications were observed. No neurologic or vascular complications were found related to pedicle screws. The rate of pedicle perforations was 8.6% (8 screws) in the conventional group and 3.0% (5 screws) in the CAS group, and in all cases, less than 2-mm displacement. None of the screws with pedicle perforation had to be revised as a result of nonsufficient biomechanical stability or compression of neural/vascular structures. Conclusions. Transpedicular screws in the cervical spine and cervicothoracic junction can be applied safely and with high accuracy in a conventional technique. Cannulated screws and the use of separate stab incisions from C3–C6 with a trocar system allow for reduced screw misplacement rates. The CAS system leads to significantly reduced screw misplacement rates. Therefore, because of the potential risk of injury to the vertebral artery and neural elements, the use of a CAS system seems to be beneficial, especially for pedicle instrumentation C3–C6.

Cement leakage during vertebroplasty: an underestimated problem?

Abstract.Overall, vertebroplasty has a low complication rate. Nevertheless, severe complications can occur. The majority of these are related to cement extrusion. The rate of cement leakage is often obtained by X-ray, with only a single leak registration per vertebra. Detection rate of leaks in comparison with CT and inter-observer reliability for X-ray is, in large parts, unknown. We conducted this study to determine the value of fluoroscopy and X-ray used to detect cement leakage as compared to CT scans. Intraoperative findings in lateral fluoroscopy by the surgeon, and postoperative findings in X-rays by two orthopaedic surgeons, were compared with CT scans for the same study group. Multiple cement leakage was considered, and agreement rate was determined. The detection rate for leaks was 34% for lateral X-ray and 48% for lateral and AP view. Additional AP views only enhanced the detection of leaks in the segmental veins. The agreement rate between fluoroscopy/X-ray and CT scans ranged between 66% and 74%, while inter-observer reliability showed only fair agreement. The rate of cement leaks in vertebroplasty is high if multiple leaks are considered in CT scans. Detection rates using X-rays are low and complicated by only fair inter-observer agreement. Leaks in the basivertebral veins are frequently misinterpreted and can lead to severe complications. Therefore, CT scans should be obtained to calculate the exact leakage rate and to assess persistent or new pain occurring postoperatively.

Adjacent segment mobility after rigid and semirigid instrumentation of the lumbar spine.

Study Design. Retrospective radiographic analysis of lumbar spine range of motion (ROM) after monosegmental fusion and posterior dynamic stabilization at the level L4–L5. Objective. Comparison of segmental ROM at the index level and the cranial and caudal adjacent levels and of global lumbar spine ROM after monosegmental fusion and posterior dynamic stabilization. Summary of Background Data. The postulated advantage of nonfusion technology compared with fusion is based on the assumption that preservation of motion at the treated segment reduces the incidence of adjacent segment effects. Therefore, it is imperative to provide evidence that dynamic stabilization devices avoid hypermobility at the adjacent segments because this might substantiate a protective effect on the adjacent segments. Methods. Twenty-six patients with low back pain and claudication due to degenerative instability at the level L4–L5 with concomitant spinal stenosis were treated either with decompression and Dynesys (n = 11) or with decompression and fusion (n = 15). All patients underwent flexion/extension radiographs before surgery and at latest follow-up. ROM was assessed at the index level (L4–L5), the cranial/caudal adjacent levels (L3–L4/L5–S1), and at the lumbar spine from L2 to S1. Results. There was a significant reduction of the global ROM of the lumbar spine (L2–S1) and the segmental ROM at the index level (L4–L5) in the fusion group, whereas adjacent level ROM did not change significantly. In the Dynesys group, no significant changes of global lumbar spine ROM (L2–S1) and segmental ROM (index level and cranial/caudal adjacent levels) were seen. Conclusion. This study shows that neither monosegmental instrumented fusion nor monosegmental posterior dynamic stabilization with Dynesys alter the ROM of the cranial and caudal adjacent levels. Consequently, monosegmental posterior dynamic stabilization with Dynesys has no effect with regard to adjacent segment mobility compared with monosegmental fusion.

The Tokuhashi Score: Significant Predictive Value for the Life Expectancy of Patients With Breast Cancer With Spinal Metastases

Study Design. Retrospective study of 55 consecutive patients with spinal metastases secondary to breast cancer who underwent surgery. Objective. To evaluate the predictive value of the Tokuhashi score for life expectancy in patients with breast cancer with spinal metastases. Summary of Background Data. The score, composed of 6 parameters each rated from 0 to 2, has been proposed by Tokuhashi and colleagues for the prognostic assessment of patients with spinal metastases. Methods. A total of 55 patients surgically treated for vertebral metastases secondary to breast cancer were studied. The score was calculated for each patient and, according to Tokuhashi, the patients were divided into 3 groups with different life expectancy according to their total number of scoring points. In a second step, the grouping for prognosis was modified to get a better correlation of the predicted and definitive survival. Results. Applying the Tokuhashi score for the estimation of life expectancy of patients with breast cancer with vertebral metastases provided very reliable results. However, the original analysis by Tokuhashi showed a limited correlation between predicted and real survival for each prognostic group. Therefore, our patients were divided into modified prognostic groups regarding their total number of scoring points, leading to a higher significance of the predicted prognosis in each group (P < 0.0001), and a better correlation of the predicted and real survival. Conclusion. The modified Tokuhashi score assists in decision making based on reliable estimators of life expectancy in patients with spinal metastases secondary to breast cancer.

Prognosis Scores of Tokuhashi and Tomita for Patients With Spinal Metastases of Renal Cancer

BackgroundRetrospective evaluation of the prognosis scores of Tokuhashi and Tomita for life expectancy in 37 consecutive patients with spinal metastases secondary to renal cancer who underwent surgery. The score of Tokuhashi, composed of six parameters, each rated from zero to two, has been proposed in 1990 for the prognostic assessment of patients with spinal metastases. In 2001, Tomita et al. created another prognostic score, composed of three parameters, growth behaviour of the primary tumor (slow, moderate and rapid) and the evidence of visceral and bony metastases.MethodsThirty-seven patients, surgically treated for vertebral metastases secondary to renal cancer were studied. The scores according to Tokuhashi and Tomita were calculated for each patient.ResultsApplying the Tokuhashi Score for the estimation of life expectancy of renal cancer patients with vertebral metastases was found to provide very reliable results with a statistically high significance. The analysis according to Tomita showed no correlation between predicted and real survival. The statistical analysis did not show any significance.ConclusionFor surgical decisions in renal cancer patients with spinal metastases, the prognostic score of Tokuhashi appears to be much more valuable than the Tomita score.

Prevalence of sleep deprivation in patients with chronic neck and back pain: a retrospective evaluation of 1016 patients.

Background Chronic low back pain (CLBP) and chronic neck pain (CNP) have become a serious medical and socioeconomic problem in recent decades. Patients suffering from chronic pain seem to have a higher prevalence of sleep disorders. Purpose To calculate the prevalence of sleep deprivation in patients with CLBP and CNP and to evaluate the factors that may contribute to sleep impairment. Methods This study was a retrospective evaluation of 1016 patients with CNP and CLBP who consulted an orthopedic department at a university hospital. Factors assessed were gender, age, diagnosis, grade of sleep deprivation, pain intensity, chronification grade, and migrational background. Pearson’s chi-squared test was performed to calculate the relationship between these factors and the grade of sleep deprivation. Regression analysis was performed to explore the correlation between the grade of sleep deprivation and age, pain intensity, and chronification grade. Results A high prevalence of sleep deprivation (42.22%) was calculated in patients with CNP and CLBP, even when analgesics had been taken. About 19.88% of the patients reported serious sleep impairments (ie, <4 hours of sleep per night). The grade of sleep deprivation did not correlate with the gender or age distribution. A significant relationship was found between the grade of sleep deprivation and pain intensity, failed back surgery syndrome, and patients with a migrational background. There was a moderate relationship with intervertebral disc disease and no relationship with spinal stenosis. Conclusion Sleep disturbance should be assessed when treating patients with CNP or CLBP, especially in patients with higher pain intensity, failed back surgery syndrome, and a migrational background. Further research is needed to explore the complex relationship of sleep disturbance and chronic pain.

Evaluation of Lumbar Spine Motion With Dynamic X-ray–a Reliability Analysis

Study Design. Radiologic evaluation of lumbar range of motion (ROM) with dynamic radiograph. Objectives. To calculate 95% confidence intervals (CIs) for the measurement error accompanying different methods, different observers, and different levels of training when measuring sagittal plane segmental ROM in lumbar spine. In addition, to compare the 95% CI with frequently common statistical methods of reliability analysis. Summary of Background Data. Dynamic radiographs are commonly used for ROM calculation of the lumbar spine. Yet, the reliability of different measurement methods still remains unclear. Methods. In 24 patients, levels L4–L5 and L5–S1 were measured with the Cobb and superimposition methods on flexion-extension radiographs. There were 2 experienced and 1 inexperienced observer that performed the measurements. The 95% CIs were compared with the corresponding Pearson correlation coefficient and P value (t test). Results. The 95% CI of the superimposition method was ±4.0° for the experienced and ±4.7° for the inexperienced observer. The corresponding values for the Cobb method was ±4.2° for the experienced and ±6.8° for the inexperienced observer. The 95% CI for the measurement error became even worse when different methods or observers were compared, whereas a method constancy revealed superior reliability than observer constancy in experienced observers. Conclusions. For lumbar ROM measurement with dynamic radiograph, the superimposition method seems to be more reliable than the Cobb method. Study protocols dealing with ROM measurement have to calculate the 95% CI of the measurement method used because clinically valid conclusions can only be drawn with respect to these intervals.

Reliability of motion measurements after total disc replacement: the spike and the fin method.

As motion preservation is one of the main postulated advantages after total disc replacement (TDR) of the lumbar spine, the quantification of the mobility after TDR seems of special clinical interest. Yet, the best method to assess range of motion (ROM) after TDR remains unclear. The aim of the study was the calculation of 95%-confidence intervals (95%-C.I.) for the measurement error accompanying: (1) different methods (2) different observers and (3) different levels of training for radiographic motion analysis after TDR. In 12 patients the level L4–L5 and in another 12 patients level L5–S1 were measured with the Cobb and the superimposition method on flexion–extension X-rays after monosegmental TDR. Both methods were adopted as the landmarks used the spikes of the prosthesis instead the endplates (spike method) and the fin of the prosthesis instead the whole vertebral body (fin method). Measurements were performed by two experienced (O-I and O-III) and one inexperienced observer (O-II). The adopted spike and fin method showed a better reliability compared to the reported results of the original Cobb and superimposition method. The method used was not clinically relevant for the intraobserver reliability in the experienced observer (95%-C.I.: ±2.0° for the fin and ±2.1 for the spike method) and for the interobserver reliability for two experienced observers (95%-C.I.: −2.8°/+2.8° for the fin and −2.9°/+3.1° for the spike method). The intraobserver reliability for the inexperienced observer was inferior for both methods compared to the experienced observer but no clinically relevant differences could be observed in interobserver reliability measures. The spike and fin method are reliable methods for study protocols dealing with angular motion after TDR as clinically valid conclusions can be drawn with an accuracy of about ±2° for the same observer and with an accuracy of about ±3° for a different observer.

Posterior component impingement after lumbar total disc replacement: a radiographic analysis of 66 ProDisc-L prostheses in 56 patients.

Study Design. Radiographic evaluation of lumbar total disc replacement (TDR). Objectives. To assess radiographically segmental angulation and mobility after lumbar TDR, to determine the rate of posterior component impingement, and to investigate the influence of implantation level and mono- versus bi-segmental implantations. Summary of Background Data. Polyethylene (PE)-wear can lead to inferior outcome after lumbar TDR due to aseptic loosening. One contributing factor might be increased segmental lordosis with component impingement. Methods. Fifty-six consecutive patients with 66 ProDisc-L (Synthes Spine, Solothurn, CH) prostheses (46 mono-segmental, 10 bi-segmental) were evaluated radiographically. All prostheses had 6° intrinsic angulation and a 10 mm PE-inlay. Segmental angulation and extension range of motion was measured twice on standing radiographs (neutral position and maximum extension) using the spike method. Component impingement was assumed if angulation of the prosthesis fins was >16°. Intraobserver variability was assessed using Pearson correlation coefficient and 95% confidence interval (95% CI). Results. The average angulation in neutral position was 9.9° (±4.8°) and 9.9° (±4.9°) at first and second measurement, respectively. In maximum extension it was 11.3° (±4.9°) and 11° (±4.9°). Pearson correlation coefficient suggested near perfect agreement (0.99) for measurement of angulation and good agreement for range of motion measurement (0.85). Ninety-five percent CI was ±1.2° and ±1.4°, respectively. Data were interpreted using absolute measurements (AM) and 95% CI, suggesting impingement if segmental angulation was >16° (AM) and >17.2° (95% CI). Regarding neutral position, 11% (AM) and 5% (95% CI) of the artificial discs showed component impingement. In extension, this increased to 15% (AM) and 9% (95% CI), respectively. Impingement was more frequent at L4/5 and in bi-segmental implantations. Extension according to AM was maintained in 52 prostheses (79%) with on average 1.4° ± 1.1°. According to the 95% CI, which required a change of >1.4°, extension was seen in 21 prostheses (32%) with on average 2.5° ± 1°. Conclusion. Posterior component impingement was seen in a considerable number of implants. With regard to potential consequences like PE-wear, further studies are needed to investigate the correlation between radiographic and clinical findings.

Early radiological outcome of ultrasound monitoring in infants with developmental dysplasia of the hips.

The purpose of this study was to evaluate the early radiological outcome after ultrasound-monitored treatment of developmental dysplasia of the hip (DDH) and to examine whether there was a correlation between the initial severity of DDH, measured by ultrasound, and the severity of residual dysplasia on the radiograph at the first follow-up. At the beginning of ultrasound-monitored treatment, the sonographic findings of 90 children (72 girls, 18 boys, mean age 7.2 weeks) with DDH (29 unilateral, 61 bilateral) were staged according to the Graf classification and assigned to four categories. Treatment was continued until normal ultrasound findings were reached. At the time children started walking (mean age 14.8 months), an anteroposterior radiograph of the pelvis was performed. The acetabular index was measured and classified according to the normal values of the hip joint, as described by Tönnis. The ultrasound findings expressed by the Graf classification were compared with the acetabular index measured at radiographic follow-up. Although normal values in ultrasound were reached before abduction splinting was discontinued, at the time of radiological follow-up, 59 hips (32.8%) showed mild residual dysplasia and another 53 hips (29.4%) showed severe residual dysplasia according to the criteria of Tönnis. Statistically, there was no significant correlation between the Graf classification and the radiological outcome at follow-up. Even after successful ultrasound-monitored treatment, a risk for residual dysplasia remains. Therefore, radiological follow-up of every hip treated once is necessary. We found no correlation between the severity of DDH measured by ultrasound and the subsequent presence of residual dysplasia at radiological follow-up.