May bending radiographs be replaced by magnetic resonance imaging in patients with adolescent idiopathic scoliosis?

PURPOSE: There is no data that shows if it is possible to determine if a curve is structural or non-structural or to assess flexibility of an adolescent idiopathic scoliosis (AIS) by magnetic resonance imaging (MRI) instead of bending radiographs (BR). We investigated if the results of BR may be compared to those of MRI. METHODS: We retrospectively analyzed prospectively collected data of patients with AIS in whom a selective spinal fusion was performed and in whom a MRI, BR and full-spine X-rays were obtained preoperatively. We measured the Cobb angles of the main and of the minor curve in full-spine X-ray (FSR), BR and MRI and analyzed the degree of the intervertebral disk degeneration in the MRI. RESULTS: After applying inclusion and exclusion criteria, 25 patients were included. We found a significant correlation (p < 0.05, Corr Coeff = 0.41) between the Cobb angle of the main curve in FSR and the Cobb angle of the main curve in the MRI and between the Cobb angle of the minor curve in FSR and the Cobb angle of the minor curve in the MRI (p < 0.001, Corr Coeff = 0.04). All patients with a minor curve of less than 25° in the BR had a Cobb angle of less than 30° in the MRI. CONCLUSION: Spinal curves showed a significant correlation between bending radiographs and recumbent images (MRI). In our group of patients, a Cobb angle of the minor curve of less than 30° in the MRI indicated that this minor curve was non-structural according to the classification of Lenke.

May bending radiographs be replaced by recumbent CT scans in patients with adolescent idiopathic scoliosis?

PURPOSE: There is no data that show if it is possible to determine if a curve is structural or non-structural or to assess flexibility of an adolescent idiopathic scoliosis (AIS) by recumbent images like a CT scan (CTS) instead of bending radiographs (BR). We investigated if the results of BR may be compared to those of CTS. METHODS: We retrospectively analyzed prospectively collected data of patients with AIS in whom a selective spinal fusion was performed and in whom a CTS, BR, and full spine x-rays were made preoperatively. We measured the Cobb angles of the main and the minor curve in full spine x-ray, BR, and CTS. RESULTS: After applying inclusion and exclusion criteria, 39 patients were included. We found a strong correlation (r = 0.806, p < 0.01) between the Cobb angle of the main curve in BR and the Cobb angle of the main curve in the CTS and between the Cobb angle of the minor curve in BR and the Cobb angle of the minor curve in the CTS (r = 0.601, p < 0.01). All patients with a minor curve of less than 25 degrees in the BR had a Cobb angle of less than 35 degrees in the CTS. CONCLUSION: Spinal curves showed a significant correlation between bending radiographs and recumbent images (CTS). In our group of patients, a Cobb angle of the minor curve of less than 35 degrees in the CTS indicated that this minor curve was non-structural.

MRI identifies biochemical alterations of intervertebral discs in patients with low back pain and radiculopathy.

KEY POINTS: • Molecular intervertebral disc damage was associated with LBP and radiculopathy.• Patients with radiculopathy and LBP demonstrated a depletion of gagCEST values compared with healthy controls.• GagCEST imaging may be a non-invasive tool for investigation of degeneration processes of lumbar intervertebral discs (IVDs). GagCEST imaging may be an imaging biomarker for biochemical IVD alterations.

Impact of Different Operative Techniques for Patients With Adolescent Idiopathic Scoliosis on Frontal Curve Correction and Sagittal Balance.

BACKGROUND: Surgical correction of adolescent idiopathic scoliosis from the posterior approach can be performed by the "all screws" technique; hybrid technique with screws and hooks; hybrid technique or with screws, hooks, and tapes; or selective fusion (SF) or nonselective fusion (NSF). The aim of the present investigation was to analyze the influence from different operative techniques on frontal curve correction and sagittal profile in patients with adolescent idiopathic scoliosis. METHODS: We conducted a retrospective analysis on 55 consecutive patients with scoliosis who had been treated by posterior instrumented fusion. We collected demographic data and analyzed pre- and postoperative radiographs. Statistical analysis was performed using SPSS version 25. Because data showed normal distribution, t tests were performed. RESULTS: Twenty-two patients were treated using the hybrid technique with screws and hooks; 25 were treated using the hybrid technique with screws, hooks, and tape; and 8 were treated using the all screws technique. An SF was performed in 32 patients and NSF in 23 patients. There was no significant difference with regard to curve correction of the main curve between the different techniques. Correction of the minor curve was significantly higher in NSF than in SF patients. In SF, there was a correction of the minor curve of 43.9%. Impact on sagittal balance showed no significant differences between NSF and SF. CONCLUSION: The different operative techniques did not show a difference with regard to the correction of the main curve. NSF showed a significantly higher degree of correction of the minor curve than SF. However, we still found a correction of 43.9% of the noninstrumented minor curve in SF. Thus, SF and hybrid techniques do not lead to inferior radiographic outcome. CLINICAL RELEVANCE: SF and hybrid techniques are safe and effective techniques that could be used as an alternative to NSF and all screw fixation in the operative treatment for scoliosis.

Navigation versus fluoroscopy in minimalinvasive iliosacral screw placement.

INTRODUCTION: When needed operative treatment of sacral fractures is mostly performed with percutaneous iliosacral screw fixation. The advantage of navigation in insertion of pedicle screws already could be shown by former investigations. The aim of this investigation was now to analyze which influence iliosacral screw placement guided by navigation has on duration of surgery, radiation exposure and accuracy of screw placement compared to the technique guided by fluoroscopy. METHODS: 68 Consecutive patients with sacral fractures who have been treated by iliosacral screws were inclouded. Overall, 85 screws have been implanted in these patients. Beside of demographic data the duration of surgery, duration of radiation, dose of radiation and accuracy of screw placement were analyzed. RESULTS: When iliosacral screw placement was guided by navigation instead of fluoroscopy the dose of radiation per inserted screw (155.0 cGy*cm2 vs. 469.4 cGy*cm2 p < 0.0001) as well as the duration of radiation use (84.8 s vs. 147.5 s p < 0.0001) were significantly lower. The use of navigation lead to a significant reduction of duration of surgery (39.0 min vs. 60.1 min p < 0.01). The placement of the screws showed a significantly higher accuracy when performed by navigation (0 misplaced screws vs 6 misplaced screws-p < 0.0001). CONCLUSION: Based on these results minimal invasive iliosacral screw placement guided by navigation seems to be a safe procedure, which leads to a reduced exposure to radiation for the patient and the surgeon, a reduced duration of surgery as well as a higher accuracy of screw placement.

Surgical Site Infection After Posterior Stabilization of the Spine - When do we Have to Remove the Implants?

STUDY DESIGN: Retrospective data analysis. OBJECTION: The primary objective of this investigation was to analyze if treatment of Postoperative surgical site infections (PSSI) after posterior stabilization of the spine (PS) without radiological signs of screw loosening (RSL) shows a sufficient success rate without implant removal and if there was any difference between early and late PSSI. SUMMARY OF BACKGROUND DATA: PSSI after PS are usually treated by implant removal and reinstrumentation if loosening of one of more screws is detected. There is presently no conclusive data that shows the success rate of the treatment of PSSI after PS without implant removal if no RSL are perceived. MATERIALS AND METHODS: All patients who were treated for a PSSI after PS without RSL in a single spine center from 12/2009 to 03/2020 were enrolled in a retrospective analysis. Patients were treated by revision surgery with debridement and irrigation and subsequent antibiotic therapy. Implant removal was performed if the initial treatment did not lead to an improvement in wound healing and normalization of laboratory values. Statistical analysis was performed by Statistical Package for the Social Sciences 25. Descriptive data are given as mean and standard error of mean, a χ 2 test was performed. RESULTS: Of the 32 enrolled patients, 17 had an early PSSI, 15 a late PSSI. In 71.9% (23/32), the PSSI was treated without implant removal: 12/17 in early PSSI, 11/15 in late PSSI. The difference was not significant ( P >0.05). One patient died, all other patients were discharged from the hospital with no remaining laboratory signs of the infection and with closed soft tissues. CONCLUSIONS: In our group of patients, the success rate of irrigation and debridement without implant removal was 71.9%. In the light of this data, performing at least two irrigations and debridement before implant removal seems to be a valid treatment option in PSSI after PS if there are no RSL in early and late PSSI.

Outcome of Targeted vs Empiric Antibiotic Therapy in the Treatment of Spondylodiscitis: A Retrospective Analysis of 201 Patients.

BACKGROUND: Antibiotic treatment of spondylodiscitis is influenced by antibiotic stewardship; specifically, empirical antibiotic therapy is avoided in favor of-delayed-targeted antibiotic therapy after microbiological diagnosis. Only patients with neurological deficits or clinical signs of sepsis should be treated by empirical antibiotic therapy. However, the level of evidence for this treatment concept is weak. PURPOSE: The aim of this study was to investigate whether patients who were treated with a nontargeted antibiotic therapy show a worse outcome than patients who were exclusively treated with targeted antibiotic therapy. STUDY DESIGN/SETTING: A retrospective single-center data analysis. PATIENT SAMPLE: We included 201 patients with spondylodiscitis who were treated at the authors' institution between 2013 and 2020. OUTCOME MEASURES: Mortality rate, time in hospital, development of laboratory parameters, and development of pain (visual analog scale). METHODS: We performed a retrospective data analysis of patients who were treated for spondylodiscitis from January 2013 to March 2020. Clinical and demographic data as well as outcome and complications were recorded and analyzed. We investigated whether patients who were treated by a nontargeted antibiotic therapy had a worse outcome than patients who were exclusively treated by targeted antibiotic therapy and which other clinical factors had an impact on clinical outcome. RESULTS: A total of 201 patients were included, 37 of whom developed sepsis during their hospital stay, and 14 of these 37 patients died. The 14 patients who died represented (10.0%) of the subgroup who received an empirical antibiotic treatment before the targeted antibiotic therapy (n = 141). There were 0 deaths in the subgroup who did not receive an empirical antibiotic treatment (P < 0.05). The time to diagnosis since admission to the hospital was 10.5 (2.2) days in patients with sepsis; in patients without sepsis, it was 5.2 (0.9) days (P < 0.05). CONCLUSIONS: Based on the results of this investigation, the authors recommend delaying antibiotic therapy until targeted antibiotic therapy is possible. Furthermore, early diagnosis of spondylodiscitis and prevention and early detection of sepsis are essential to reduce the mortality rate of patients with spondylodiscitis.

Bovine-derived xenograft is a viable bone graft substitute in multilevel, instrumented, spinal fusion.

Objective: To evaluate radiological outcomes following the use of xenogeneic bone graft substitute (BGS) in patients undergoing multisegmental spinal fusion. Summery of Background Data: Data exists for single level and short segment fusions, there presently is a paucity of data on fusion rate after bone augmentation with BGS in multisegmental posterior spinal fusion (PSF). The leading concern is pseudarthrosis, which often leads to a loss of correction after PSF. Therefore, the bone graft is an essential aspect of PSF. Methods: We retrospectively analysed the radiological data of a consecutive cohort of patients who had been treated for adolescent idiopathic scoliosis (AIS) via multisegmental spinal fusion, in whom a bovine derived BGS had been used and had a complete dataset of 24 months follow-up. The Cobb angle of the main curve was measured pre-operatively and then at 6, 12 and 24 months post-operatively. Loosening of the screws was recorded at the same post-operative time points. Results: After applying inclusion and exclusion criteria, 28 patients were included. We found no significant change of the cobb angle from the main curve as well as the cobb angle from the thoracic kyphosis during the 24 months of follow up. No patient showed a lack of bony fusion. There was 1 revision surgery, which was due to trauma. Conclusion: In this cohort, all patients showed successful bone fusion during a 24-month follow-up. Additionally, there was no change in the Cobb angle during the 2-year post-operative period. Our data indicates that the use of bovine-derived BGS supports bone fusion after multisegmental posterior instrumented fusion of the spine.

Patterns of Intervertebral Disk Alteration in Asymptomatic Elite Rowers: A T2* MRI Mapping Study.

Background: Repetitive loading of the back puts elite rowers at risk for acute and chronic back injuries. Hypothesis: That asymptomatic elite rowers would demonstrate characteristic intervertebral disk (IVD) alterations on T2* magnetic resonance imaging (MRI) mapping compared with asymptomatic nonrowers. Study Design: Cross-sectional study; Level of evidence, 3. Methods: This study included 20 asymptomatic elite rowers (mean age, 23.4 ± 3.03 years; 9 women, 11 men) studied at 2 different times, once before (t 1) and once after (t 2) the competition phase. MRI including T2* mapping was performed on a 3-T scanner. The authors derived normative T2* data from a previous study on 40 asymptomatic volunteers (20 men, 20 women) who were not competitive rowers; based on complete T2* data sets, 37 controls were included. T2* values were compared between groups in 4 lumbar IVDs, and midsagittal T2* values were compared in 5 zones: anterior annulus fibrosus (AF), anterior nucleus pulposus (NP), central NP, posterior NP, and posterior AF. The Pfirrmann grade was used for morphological assessment of disk degeneration. Statistical analysis was conducted using the Mann-Whitney U test, Wilcoxon matched-pairs test, and Spearman rank correlation coefficient. Results: Lower T2* values were noted in the rower group compared with the controls (37.08 ± 33.63 vs 45.59 ± 35.73 ms, respectively; P < .001). The intersegmental comparison revealed lower mean T2* values among rowers (P ≤ .027 for all). The interzonal comparison indicated significantly lower mean T2* values for the rowers in all zones except for the anterior NP (P ≤ .008 for all). Lower mean T2* values were observed for the rowers at t 1 versus t 2 (39.25 ± 36.19 vs 43.97 ± 38.67 ms, respectively; P = .008). The authors noted a higher level of IVD damage according to Pfirrmann assessment in the rower cohort (P < .001); the Pfirrmann grade distributions of rowers versus controls, respectively, were as follows: 51.3% versus 73.7% (grade 1), 20.5% versus 19.5% (grade 2), 21.8% versus 6.8% (grade 3), 5.1% versus 0% (grade 4), and 1.3% versus 0% (grade 5). The authors also noted a correlation between low T2* and high Pfirrmann grade at t 1 (r =-0.48; P < .001) and t 2 (r =-0.71; P < .001). Conclusion: The cohort of elite rowers revealed more degenerative IVD changes compared with controls. The T2* values suggest that repetitive loading of the spine has demonstrable short-term and possibly permanent effects on the lumbar IVD.

Evaluating Lumbar Intervertebral Disc Degeneration on a Compositional Level Using Chemical Exchange Saturation Transfer: Preliminary Results in Patients with Adolescent Idiopathic Scoliosis.

Lumbar intervertebral disc (IVD) degeneration is characterized by structural and compositional changes. This study aimed to assess the glycosaminoglycan (GAG) content of IVDs of patients with adolescent idiopathic scoliosis (AIS) and healthy controls using GAG chemical exchange saturation transfer (gagCEST) imaging. Ten AIS patients (mean age 18.3 ± 8.2 years) and 16 healthy controls (mean age 25.5 ± 1.7 years) were included. Clinical standard morphologic MR images (T1w-, T2w-, and STIR-sequences), to rule out further spinal disorders and assess IVD degeneration using the Pfirrmann score, and compositional gagCEST sequences were acquired on a 3T MRI. In AIS patients, the most distal scoliotic curve was determined on whole-spine conventional radiographs and morphological MRI and IVDs were divided as to whether they were affected by scoliotic deformity, i.e., proximal (affected, aIVDs) or distal (unaffected, uaIVDs) to the stable vertebra of the most distal scoliotic curve. Linear mixed models were used to compare mean gagCEST-values. Over all segments, AIS-patients' IVDs exhibited significantly lower gagCEST-values than the controls: 2.76 [2.32, 3.20]% (AIS), 3.51 [3.16, 3.86]% (Control); p = 0.005. Meanwhile, no significant differences were found for gagCEST values comparing aIVDs with uaIVDs. In conclusion, as a powerful diagnostic adjunct, gagCEST imaging may be prospectively applied to detect early compositional degenerative changes in patients suffering from AIS.

Non-Specific Low Back Pain and Lumbar Radiculopathy: Comparison of Morphologic and Compositional MRI as Assessed by gagCEST Imaging at 3T.

Using glycosaminoglycan Chemical Exchange Saturation Transfer (gagCEST) magnetic resonance imaging (MRI), this study comparatively evaluated the GAG contents of lumbar intervertebral disks (IVDs) of patients with non-specific low back pain (nsLBP), radiculopathy, and asymptomatic volunteers to elucidate the association of clinical manifestation and compositional correlate. A total of 18 patients (mean age 57.5 ± 22.5 years) with radiculopathy, 16 age-matched patients with chronic nsLBP and 20 age-matched volunteers underwent standard morphologic and compositional gagCEST MRI on a 3T scanner. In all cohorts, GAG contents of lumbar IVDs were determined using gagCEST MRI. An assessment of morphologic IVD degeneration based on the Pfirrmann classification and T2-weighted sequences served as a reference. A linear mixed model adjusted for multiple confounders was used for statistical evaluation. IVDs of patients with nsLBP showed lower gagCEST values than those of volunteers (nsLBP: 1.3% [99% confidence intervals (CI): 1.0; 1.6] vs. volunteers: 1.9% [99% CI: 1.6; 2.2]). Yet, IVDs of patients with radiculopathy (1.8% [99% CI: 1.4; 2.1]) were not different from patients with nsLBP or volunteers. In patients with radiculopathy, IVDs directly adjacent to IVD extrusions demonstrated lower gagCEST values than distant IVDs (adjacent: 0.9% [99% CI: 0.3; 1.5], distant: 2.1% [99% CI: 1.7; 2.5]). Advanced GAG depletion in nsLBP and directly adjacent to IVD extrusions in radiculopathy indicates close interrelatedness of clinical pathology and compositional degeneration.

MRI based analysis of grade of spinal canal stenosis and grade of compression of nerve root by lumbar disc herniation as tools to predict probability to need surgical treatment.

BACKGROUND: Patients with a lumbar disc herniation (LDH) without high-grade neurological deficit (PWN) are usually treated non-operatively. If non-operative treatment is not successful, a postponed surgical treatment is performed. Postponed surgery is reported to show later improvement of pain and health-related quality of life and later return to work than early surgery. There are presently no objective parameters to predict if non-operative treatment may be successful in PWN, or if an early surgical treatment could be performed. METHODS: To analyze if high-grade spinal canal stenosis lead to a higher rate of surgical treatment in PWN, we conducted a retrospective single-center cohort study and included PWN with acute onset of severe radicular pain (VAS ≥8). We excluded patients with workers' compensation involvement, chronic pain syndrome, motor deficit <3/5, malignancy and history of prior spinal surgery. All patients were initially treated by the same standardized non-operative treatment. It was monitored if patients eventually choose an operative treatment or not. After a power analysis (aiming at >0.8), 1,053 consecutive patients (02.2008 to 12.2017) were identified by diagnostic code. One hundred and eight patients were enrolled in our investigation. Thirty-nine patients were treated non-operatively (Group 1), 69 were treated by operation (Group 2). RESULTS: Percent (%) spinal canal compromise based on cross-sectional area of LDH was 26.3% in Group 1, 33.7% in Group 2. The difference was significant (P<0.025). CONCLUSIONS: The investigated group of PWN had a significantly higher probability to need surgical treatment if they had a high-grade stenosis of the spinal canal. However, these results do not constitute a general indication for surgical treatment of PWN. The results of this study merely provide information for patients, and spine specialists, to be implemented in an individual decision-process that leads to a recommendation for type of treatment.

Effective dose of radiation per screw in surgery of adolescent idiopathic scoliosis: matched pair analysis of 293 pedicle screws inserted using three different techniques.

PURPOSE: Reports on heterogenous groups of patients have indicated that pedicle screw insertion guided by navigation (PIN) leads to, for the patient, higher doses of radiation compared with pedicle screw insertion guided by fluoroscopy (PIF). This would be a major concern, especially in paediatric deformity correction. METHODS: After a power analysis (aiming at > 0.8) 293 pedicle screws which were inserted in patients with adolescent idiopathic scoliosis were analyzed by comparing effective dose and fluoroscopy time per screw for three different techniques. Groups 2 and 3 were matched to Group 1 by Lenke type of scoliosis. Group 1 were prospectively enrolled consecutive patients that have been operated on by PIN with image acquisition by preoperative CT scan (CTS). Group 2 were consecutive retrospectively matched patients who have been operated on by PIN with image acquisition by an intraoperative 3D scan (3DS). Group 3 were consecutive retrospectively matched patients who have been operated on by PIF. RESULTS: Mean dose of radiation per screw was 1.0 mSv (sd 0.8) per screw in CTS patients, 0.025 mSv (sd 0.001) per screw in 3DS patients and 0.781 mSv (sd 0.12) per screw in PIF patients. The difference was significant (p < 0.0001). CONCLUSION: When we compared different techniques of navigation, navigation by image acquisition with CTS showed a significantly higher (by 97.5%) dose of radiation per screw for the patient than navigation by image acquisition by a 3DS. Navigation by 3DS showed significantly lower effective dose per screw for the adolescent patients than the fluoroscopic technique. LEVEL OF EVIDENCE: II.

Histologic examination of the shoulder capsule shows new layer of elastic fibres between synovial and fibrous membrane.

PURPOSE: In the present study, a systematic histological analysis of the glenohumeral joint capsule was conducted. MATERIALS AND METHODS: 12 cadaveric shoulders were examined. Inclusion criteria were: 1) intact joint capsule and 2) fixation in neutral position. The tissue samples were Elastica Hematoxylin-van-Gieson-(ElHvG) stained and diameter, quantity, and distribution patterns were analyzed. RESULTS: We detected a new layer (elastic boundary layer, EBL) between the synovial and fibrous membrane. The elastic fibres of the EBL differ considerably in diameter, quantity, and distribution pattern. CONCLUSIONS: A previously undescribed layer was noticed, which we named elastic boundary layer for now.

Signal Intensity of Lumbar Disc Herniations: Correlation With Age of Herniation for Extrusion, Protrusion, and Sequestration.

BACKGROUND: There is presently insufficient data on small groups of patients, without focus on time since herniation occurred and without establishing a valid method of measurement for signal intensity (SI) of a lumbar disc herniation (LDH) in a standard magnetic resonance imaging (MRI). SI could be reported in relation to SI of nucleus pulposus of herniated intervertebral disc, nucleus pulposus of a healthy "control" intervertebral disc, cerebral spinal fluid, or anterior anulus fibrosus. It is not known which signal intensity ratio (SIR) shows the highest correlation with time since onset of pain and how SIR of different Combined Task Forces (CTF)-types of herniation develop over time. METHODS: Out of 1053 patients, we enrolled 151 patients to a retrospective single-center analysis of standard MRIs of consecutive patients treated for LDH from February 2008 to December 2017 with confirmed (surgery, injection, or electrophysiologic testing) radicular pain by LDH and known exact date of onset of pain. We excluded patients < 18 or > 70 years, with chronical pain syndrome, spinal deformity, and history of prior spinal surgery on the affected spinal level. Because data did not show normal distribution, we assessed correlation by Spearman rank correlation coefficient. Correlation (R) and coefficient of correlation (CC) are reported. RESULTS: SI of LDH referenced by SI of nucleus pulposus of the affected intervertebral disc and CTF type "extrusion" showed the highest correlations with time since onset of pain (R: -0.893; CC: 79.7), followed by CTF-type "sequestration" (R: -0.356; CC: 12.7). CONCLUSIONS: SIR of extrusion referenced by nucleus pulposus of the affected intervertebral disc does show a high correlation with days since onset of herniation and may be applied to monitor changes of SI of LDH after herniation in standard MRIs of the lumbar spine.

Position of the acromioclavicular joint and relation to the critical shoulder angle in shoulders with rotator cuff tears.

OBJECTIVE: To evaluate the position of the acromioclavicular joint (ACJ) and relation to the critical shoulder angle (CSA) in shoulders with rotator cuff tears (RCT). METHODS: In a matched pair study including 75 shoulders with arthroscopically validated RCT and 75 controls (mean age 59.4 ± 7.9 years) the position of the ACJ in relation to the glenoid and the CSA were measured on true ap radiographs. RESULTS: The CSA is larger (p = 0.0018) and the position of the ACJ is more lateral (p = 0.0016) in shoulders with RCT in comparison to matched controls. CONCLUSION: The more lateral position of the ACJ in shoulders with a large CSA might be an additional component in the multifactorial pathogenesis of RCT.

Lumbar lordosis as tool to assess the level of pain in patients with low back pain after lumbar disc herniation.

BACKGROUND: It is presently unknown if lumbar lordosis (LL) might be applied to monitor low back pain (LBP) in patients with lumbar disc herniation (LDH). There is presently only conflicting data that does not show a correlation of LL with LBP: Previous studies do either include chronic LBP or do not consider that each patient has an individual value of LL that cannot be compared to other patients. METHODS: Power analysis: At least 32 patients had to be enrolled in the study. Out of 84 consecutive patients with acute onset of pain (<6 weeks) that were treated operatively from 11/2015 to 04/2017 by microscopic laminotomy for LDH, 35 were enrolled in this retrospective within - subject analysis after exclusion of patients with chronic LBP or severe disc degeneration of the lumbar spine. We recorded self - reported assessment of pain (VAS) and LL before the operation, 1 week and 6 weeks after the operation. We performed a paired - samples t - test (within - subject) to compare means of LL at admission to our institution with LL 6 weeks after surgery. Pearson's correlation was determined for LL and VAS. Significance level was set at p < 0.05. RESULTS: VAS at admission to our institution was 7.1 (0.4), VAS 6 weeks after surgery was 1.0 (0.3).LL at admission to our institution was 40.0 (2.1), LL 6 weeks after surgery was 48.0 (1.8). The difference was significant (p < 0.0005) with a high statistical power (1-ß = 0.99).Correlation of LL and VAS was significant (p < 0.01, r = -0.32). CONCLUSIONS: The increase of lumbar lordosis following surgery is significantly correlated to the decrease in the level of perceived pain in patients with a LDH and may be used as an additional tool to monitor the success of treatment in the investigated group of patients.

Navigation Versus Fluoroscopy in Multilevel MIS Pedicle Screw Insertion: Separate Analysis of Exposure to Radiation of the Surgeon and of the Patients.

STUDY DESIGN: This study was a retrospective radiographic analysis of consecutive patients. OBJECTIVES: To analyze exposure to radiation of the surgeon and-separately-of patients in minimally invasive surgery (MIS) of multilevel posterior stabilization by percutaneous pedicle screw insertion guided by navigation (PIN) versus percutaneous pedicle screw insertion guided by fluoroscopy (PIF). SUMMARY OF BACKGROUND DATA: Spine surgeons are exposed to a 12-fold higher dose of radiation than other nonspinal musculoskeletal surgeons and PIF in MIS leads to a 2-fold higher dose of radiation than in open surgery. PIN might reduce the dose of radiation for the surgeon and the patient, especially in multilevel MIS surgery. To the best of our knowledge, there are only rare data of short-segment fusions that do not focus on exposure to radiation of surgeons. METHODS: After power analysis, we included 205 consecutive screws (22 patients). We monitored dose of radiation (recorded separately for patient and surgeon), accuracy of screw placement, time of operation, and approach-related complications. RESULTS: In PIN, only 58.7% of dose area product (cGy×cm) per screw of PIF was determined for patients (P<0.01). The surgeon was only exposed to 19.9% of radiation per screw in PIN compared with dosage in PIF (P<0.01). Four of 205 screws (2.0%) were classified as being incorrectly positioned: 2 of 87 screws (2.3%) in PIF and 2 of 118 screws (1.7%) in PIN (P>0.05). We did not observe any wound infections. CONCLUSIONS: PIN in MIS is a safe procedure and does, compared with PIF, lead to significant reduction of radiation dose for patients and-even more-for spine surgeons.

Adjacent segment degeneration and topping off. Never stop at the apex!

We investigated if applying the Transition system (Globus Medical Inc., Audubon, PA, USA) as topping off can prevent Adjacent Segment Degeneration (ASD) and if rate of ASD is increased if instrumentation stopped at the apex of the Lumbar Lordosis (LL). We enrolled 99 consecutive patients in a retrospective study who have been operated by instrumented fusion of the lumbar spine. Thirty patients were treated by topping of (Group 1), 69 patients received the standard procedure (Group 2). 18 patients of group 1 (60%) and 38 patients of group 2 (55%) developed ASD. The difference was not significant (P>0.05). In 17 patients (17%) instrumentation stopped at apex of LL. 14/17 patients (82%) developed an ASD. This influence was significant (P<0.05). Instrumented fusion of the lumbar spine should not stop at the apex of the lumbar curve. Topping off by hybrid dynamic fixation does not reduce the rate of ASD.

T2* Mapping of the Adult Intervertebral Lumbar Disc: Normative Data and Analysis of Diurnal Effects.

In this prospective study, we sought to establish normative data for T2* analysis of lumbar intervertebral discs (IVDs). Further, potential diurnal effects regarding T2* relaxometry of the lower spine were examined. Lumbar IVDs of young, healthy, adult men (n = 20) and women (n = 20; mean age = 24.5 ± 2.9 years) were assessed. Magnetic resonance imaging including T2* mapping was performed on a 3-T scanner. Mid-sagittal T2* values were obtained in five regions: anterior annulus fibrosus (AF), anterior nucleus pulposus (NP), central NP, posterior NP, and posterior AF. Zonal and segmental differences, as well as diurnal variations between the T2* analysis in the morning and the evening and effects of unloading, were analyzed. Discs with signs of degeneration on morphological images or imaging artifacts were excluded. We noted a zonal and segmental T2* distribution with high values in the NP, low T2* values in the AF and a T2* increase towards the caudal NP. We observed no diurnal differences between the mean T2* values in the morning and in the evening (p = 0.748). The effect of unloading the spine was low (maximum T2* difference between four measurements = 13.6 ms; significant difference noted only between the 0 and 15-min measurement). The T2* values obtained in this study will serve as normative values for future T2* measurements. There are no diurnal influences, and we suggest that unloading of the spine has no demonstrable effect after 30 min on the T2* results. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1956-1962, 2019.