Automated patellar height assessment on high-resolution radiographs with a novel deep learning-based approach.

BACKGROUND: Artificial intelligence and deep learning have shown promising results in medical imaging and interpreting radiographs. Moreover, medical community shows a gaining interest in automating routine diagnostics issues and orthopedic measurements. AIM: To verify the accuracy of automated patellar height assessment using deep learning-based bone segmentation and detection approach on high resolution radiographs. METHODS: 218 Lateral knee radiographs were included in the analysis. 82 radiographs were utilized for training and 10 other radiographs for validation of a U-Net neural network to achieve required Dice score. 92 other radiographs were used for automatic (U-Net) and manual measurements of the patellar height, quantified by Caton-Deschamps (CD) and Blackburne-Peel (BP) indexes. The detection of required bones regions on high-resolution images was done using a You Only Look Once (YOLO) neural network. The agreement between manual and automatic measurements was calculated using the interclass correlation coefficient (ICC) and the standard error for single measurement (SEM). To check U-Net's generalization the segmentation accuracy on the test set was also calculated. RESULTS: Proximal tibia and patella was segmented with accuracy 95.9% (Dice score) by U-Net neural network on lateral knee subimages automatically detected by the YOLO network (mean Average Precision mAP greater than 0.96). The mean values of CD and BP indexes calculated by orthopedic surgeons (R#1 and R#2) was 0.93 (± 0.19) and 0.89 (± 0.19) for CD and 0.80 (± 0.17) and 0.78 (± 0.17) for BP. Automatic measurements performed by our algorithm for CD and BP indexes were 0.92 (± 0.21) and 0.75 (± 0.19), respectively. Excellent agreement between the orthopedic surgeons' measurements and results of the algorithm has been achieved (ICC > 0.75, SEM < 0.014). CONCLUSION: Automatic patellar height assessment can be achieved on high-resolution radiographs with the required accuracy. Determining patellar end-points and the joint line-fitting to the proximal tibia joint surface allows for accurate CD and BP index calculations. The obtained results indicate that this approach can be valuable tool in a medical practice.

Femoroacetabular impingement in the unpinned contralateral hip in patients with primary unilateral slipped capital femoral epiphysis: preliminary radiographic outcomes.

The study evaluated femoroacetabular impingement (FAI) in the unpinned contralateral hip in patients with unilateral slipped capital femoral epiphysis (SCFE) and verified initial age, posterior sloping angle (PSA) and center-edge angle (CEA) as predictors of FAI in the contralateral hip. 152 patients with unilateral SCFE with a mean index age of 13.2 years (8.2-17.2 years) were enrolled retrospectively into the study. Mean follow-up was 8 years (3-14 years). PSA and CEA were measured on initial radiographs of the unaffected hip. Alpha-angle and CEA were measured on radiographs taken at the last follow-up to identify FAI. Four groups of patients were distinguished: (1) no FAI (10 patients, 17.54%); (2) CAM-type FAI (41 patients, 71.9%); (3) pincer-type FAI (3 patients, 5.26%) and (4) mixed-type FAI (13 patients, 22.8%). The mean PSA was 12.1°, 12°, 16.8°, 11.9° for groups 1, 2, 3 and 4, respectively, with no significant difference ( P = 0.65). The mean initial CEA for groups 1, 2, 3 and 4 was 34.4°, 35.5°, 42° and 42° respectively, with significant differences between groups 1 versus 4 ( P = 0.034) and 2 versus 4 ( P = 0.009). Conclusions are as follows: 1. Radiographic features of FAI were present in 85.1% of unpinned contralateral hips in patients with unilateral SCFE. 2. 71.9% of unpinned contralateral hips developed CAM deformity. 3. CEA can be used in predicting pincer-type FAI in the contralateral hip in unilateral SCFE. 4. PSA and age revealed negligible value in predicting FAI.

Can we still use X-rays to predict contralateral slip in primary unilateral slipped capital femoral epiphysis?

The objective of this study was to assess subsequent contralateral slip (SCS) in the unaffected hip in patients with primary unilateral slipped capital femoral epiphysis (SCFE) using three radiographic parameters: posterior sloping angle (PSA), center-edge angle (CEA) and triradiate cartilage (TC) appearance. A total of 152 patients admitted to two pediatric units between 2001 and 2015 were divided into three groups: A - underwent prophylactic fixation of the unaffected hip at the time of index surgery- high clinical risk of SCS; B - no clinical risk factors but SCS occurred; C - no issues regarding the contralateral hip during follow-up. The mean PSA for groups A, B and C were 22°(6-49), 17°(9-24) and 13°(0-27), respectively. PSA was significantly higher in Group A than in Group C ( P < 0.0001). The differences in PSA between groups A and B, but also B and C were insignificant ( P = 0.12 and p=0.21, respectively). The mean CEA in groups A, B and C was 33(25-43), 35(26-42) and 37(17-53), respectively. CEA did not differ significantly between groups A, B and C ( P = 0.25). Assessment of TC did not differ significantly between the groups ( P = 0.66). Observation of TC in groups B and C combined revealed that the cartilage was open in 65% of 77 patients and 14% of them developed SCS; whereas among the 35% of patients with ossified TC only 7% developed SCS (OR=2.0). PSA and CEA alone have no predictive value in determining the risk of contralateral slip. The absence of TC results in a two-fold decrease in the likelihood of developing an SCS. The decision of prophylactic surgical treatment of the contralateral hip in primary unilateral SCFE should not be based solely on radiographic findings.

Periprosthetic Joint Infections Caused by Candida Species-A Single-Center Experience and Systematic Review of the Literature.

BACKGROUND: The aim of this study was to analyze the treatment results of fungal periprosthetic joint infections (PJI) caused by Candida species from a single orthopedic center and to compare them with reports from other institutions. METHODS: Eight patients operated on from January 2014 to December 2021 met the inclusion criteria and were analyzed in terms of clinical outcomes. A systematic review of the literature identified 153 patients with Candida PJIs extracted from 12 studies according to the PRISMA (Preferred Reporting Item for Systematic Reviews and Meta-Analyses) guidelines. RESULTS: The success rate of the treatment in the case series was 50%. The most frequent pathogens were Candida albicans (three cases; 37.5%) and Candida parapsilosis (three cases; 37.5%). In one patient (12.5%), bacterial co-infection was noted, and in five patients (62.5%) significant risk factors of PJI were confirmed. The overall success rate on the basis of data collected for systematic review was 65.5%. A sub-analysis of 127 patients revealed statistically significant differences (p = 0.02) with a higher success rate for the knees (77.6%) than for the hips (58%). In 10 studies the analysis of risk factors was performed and among 106 patients in 77 (72.6%) comorbidities predispose to fungal PJI were confirmed. Bacterial co-infection was noted in 84 patients (54.9%). In 93 patients (60.7%) Candida albicans was the culprit pathogen, and in 39 patients (25.5%) Candida parapsilosis was the culprit pathogen. Based on these two most frequent Candida species causing PJI, the success rate of the treatment was statistically different (p = 0.03), and was 60.3% and 83.3%, respectively. The two-stage strategy was more favorable for patients with Candida parapsilosis infections (94.4% success rate) than the one-stage protocol (50% success rate; p = 0.02); as well as in comparison to the two-stage treatment of Candida albicans (65% success rate; p = 0.04). CONCLUSIONS: The analysis of the literature showed no differences in the overall success rate between one- and two-stage surgical strategies for all Candida species, but differed significantly comparing the two most frequent strains and concerning PJI localization. The frequent presence of bacterial co-infections makes it necessary to consider the additional administration of antibiotics in the case of fungal PJI.

Shaft Fractures in Patients Requiring Primary or Revision Total Knee Arthroplasty Can Be Successfully Treated with Long-Stemmed Implants without Additional Fixation.

The aim of this study was to evaluate the bone union, complication rate, clinical and functional outcomes of long-stemmed total knee arthroplasty (TKA) in patients with periprosthetic femoral or tibial shaft fractures and in patients with femoral or tibial shaft fractures with coexisting advanced knee osteoarthritis (OA). This retrospective study comprised 25 patients who underwent surgery due to tibial or femoral shaft fractures: (1) with coexisting severe knee OA or (2) with a periprosthetic fracture requiring implant exchange. In all cases, fracture stabilization was performed intramedullary with the use of long-stemmed implants without the use of additional fixation material (plates, screws, or cerclage). Bone union was achieved in 22/25 patients (88%). One patient required revision with additional plate stabilization due to non-union, and asymptomatic partial bone union was observed in two cases. The group with periprosthetic fractures demonstrated good clinical (mean 73.1 ± 13.3) and moderate functional (mean 59.2 ± 18.8) outcomes in the Knee Society Scoring system (KSS). In the group with shaft fracture and coexisting OA significantly higher clinical (excellent results, mean 84.1 ± 11; p = 0.03) and functional (good results, mean 76.2 ± 20.6; p = 0.04) results were noted. There were no statistically significant differences in terms of range of motion (ROM) or complication rate between these two groups. One-stage TKA with a long-stemmed implant without the use of additional fixation material is an effective method for the treatment of femoral or tibial shaft fractures in patients who require joint replacement. Despite being technically demanding, the approach yields bone union and moderate to excellent clinical and functional outcomes with a relatively low complication rate.

Pelvic incidence and pelvic tilt can be calculated using either the femoral heads or acetabular domes in patients with hip osteoarthritis.

AIMS: The aim of the study was to compare two methods of calculating pelvic incidence (PI) and pelvic tilt (PT), either by using the femoral heads or acetabular domes to determine the bicoxofemoral axis, in patients with unilateral or bilateral primary hip osteoarthritis (OA). METHODS: PI and PT were measured on standing lateral radiographs of the spine in two groups: 50 patients with unilateral (Group I) and 50 patients with bilateral hip OA (Group II), using the femoral heads or acetabular domes to define the bicoxofemoral axis. Agreement between the methods was determined by intraclass correlation coefficient (ICC) and the standard error of measurement (SEm). The intraobserver reproducibility and interobserver reliability of the two methods were analyzed on 31 radiographs in both groups to calculate ICC and SEm. RESULTS: In both groups, excellent agreement between the two methods was obtained, with ICC of 0.99 and SEm 0.3° for Group I, and ICC 0.99 and SEm 0.4° for Group II. The intraobserver reproducibility was excellent for both methods in both groups, with an ICC of at least 0.97 and SEm not exceeding 0.8°. The study also revealed excellent interobserver reliability for both methods in both groups, with ICC 0.99 and SEm 0.5° or less. CONCLUSION: Either the femoral heads or acetabular domes can be used to define the bicoxofemoral axis on the lateral standing radiographs of the spine for measuring PI and PT in patients with idiopathic unilateral or bilateral hip OA. Cite this article: Bone Joint J 2021;103-B(8):1345-1350.

The Effect of the COVID-19 Pandemic on Total Hip and Knee Arthroplasty Surgical Volume in 2020 in Poland.

The aim of this study was to analyse the effect of the first year of the COVID-19 pandemic on total hip arthroplasty (THA) and total knee arthroplasty (TKA) surgical volume in Poland. A retrospective analysis of data concerning THA and TKA collected by the National Health Fund in Poland in 2019 and in 2020 has been conducted. The number of primary hip or knee arthroplasties in 2020 was around 71% and 67% of the number registered in 2019, respectively. There was also a decline in the volume of revision arthroplasties observed, with 65% and 63% of THA and TKA revisions performed in 2019. The most significant decrease was observed in April and May, and during the second wave of the pandemic in November 2020, with a decline of 87%, 55% and 56%, respectively. The results of this study show the significant impacts that the COVID-19 pandemic had on the volume of elective hip and knee arthroplasties in Poland in 2020. In comparison with 2019, a decrease of around 30% for primary and of 40% for revision arthroplasties was observed. The most significant decline was observed in April and May 2020, and during the second wave of the COVID-19 pandemic in Poland in November 2020.

Sagittal body alignment in a sitting position in children is not affected by the generalized joint hypermobility.

Back pain may be related to an improper sitting position. The aim of the study was to assess the sagittal curvatures of the spine in a sitting position in children with generalized joint hypermobility (GJH). The study included 302 children aged 8-14 years. The sagittal curvatures of the spine (sacral slope, lumbar lordosis, thoracic kyphosis with its lower and upper part) were assessed using the Saunders digital inclinometer. In order to assess GJH a 9-point Beighton scale was used. The study revealed no significant differences (p > 0.05) in sagittal curvatures of the spine in a relaxed sitting position between children with and without GJH. Regardless of the occurrence of GJH, kyphotic alignment of the spine was noted in a relaxed sitting. GJH does not affect the position of the trunk in a sagittal plane in a relaxed sitting position in children aged 8-14 years. A relaxed sitting position in children with and without GJH is characterized by a kyphotic position of the spine caused by an improper position of pelvis and lumbar segment of the spine.

Parasitosis of the vertebral canal mimicking lumbar intervertebral disc herniation: a case report.

STUDY DESIGN: Case report. BACKGROUND: It is a case of dracunculiasis of the spine mimicking lumbar intervertebral disc herniation. CASE PRESENTATION: A 57 year-old Caucasian male was admitted to the hospital because of the left L5 radiculopathy lasting for 2 months. The pain in the left lower limb was associated with muscle weakness on dorsal flexion of the foot, paresthesia of the dorsal aspect of the foot and tingling in the big toe. Neurological examination revealed: muscle weakness on dorsal flexion of the foot, impaired light touch and pin prick test on the dorsal aspect of the foot and positive Lasègue's sign. Magnetic resonance imaging (MRI) examination revealed L4-L5 intervertebral disc herniation with sequester compressing the left L5 nerve root. The open L4-L5 left side discectomy was performed. During the sequester evacuation 3 pieces of nematodes were removed and preserved in 10% of formaldehyde solution. After the surgery the patient was pain free with normal neurological examination. The diagnosis of dracunculiasis was based on the morphology of the nematode and on exclusion of the other parasites. DM infestation could not be confirmed with molecular testing that was impaired by the formaldehyde. CONCLUSIONS: Parasite infestation should be considered even in cases with obvious MRI of lumbar intervertebral disc herniation. If a nematode was found accidentally during any surgery it should be preserved in a 0.9% saline, not in formaldehyde, not to disturb the molecular tests.

Elevated plasma D-dimer concentration has higher efficacy for the diagnosis of periprosthetic joint infection of the knee than of the hip-A single-center, retrospective study.

The aim of this study is to evaluate the value of D-dimers in the diagnosis of periprosthetic joint infection (PJI). The analysis was performed for revision total hip (rTHA) and revision total knee arthroplasty (rTKA) together and separately with two thresholds, one calculated by statistical methods and the second adopted from the ICM 2018 definition. The study group comprised 133 patients who underwent rTHA or rTKA: 68 patients diagnosed according to the ICM 2018 definition (PJI group) and 65 with aseptic implant loosening, instability, malposition, or implant failure with the exclusion of infection (aseptic revision total joint arthroplasty or arTJA group). Mean D-dimer concentrations were 0.36 ± 0.25 µg/ml in the arTJA group and 0.87 ± 0.78 µg/ml in the PJI group (p < .001). For rTHA and rTKA together, the sensitivity and specificity of the evaluation were 75% and 73.8% according to the calculated cut-off value (0.45 µg/ml), and 33.8% and 95.4% based on the ICM 2018 threshold (0.85 µg/ml). Separately, for rTHA, sensitivity and specificity were 62.5% and 62.1% for the calculated value (0.43 µg/ml) and 6.3% and 96.6% for the ICM 2018 threshold; for rTKA, sensitivity was 86.1% and specificity was 88.9% for the calculated threshold (0.48 µg/ml) and 58.3% and 94.4% for the ICM 2018 value. Our findings indicate that plasma D-dimers have potential as markers of knee PJI, but moderate to low value for hip PJI.

Analysis of Radiographic Parameters of Sagittal Spinopelvic Alignment: Polish Nomenclature and Clinical Implications.

Over the last 30 years, many authors have suggested that the shape of the human spine in the sagittal plane is helpful in understanding its physiology and pathology. This paper presents the current views and Polish no-men-clature used for the assessment of the morphology and position of the pelvis in the sagittal plane. The va-lues of particular radiographic parameters are presented for healthy individuals and for patients with selected spinal pathologies. Moreover, the paper discusses the practical application of the radiographic parameters that describe the shape and position of the pelvis in the sagittal plane.

Diurnal variation of body height in children with idiopathic scoliosis.

BACKGROUND: Body height (BH) measurement is an important part of the clinical evaluation of children with idiopathic scoliosis (IS) as its progression is defined based on the observation of a growth spurt. OBJECTIVE: The aim of the study is to assess diurnal variation of BH in children with IS. METHODS: BH was measured in 98 children with IS (Cobb angle: 10∘-52∘, mean 21.2∘± 9.9∘) both in standing and sitting position. The measurements were performed 4 times a day - between: (1) 7:00 and 8:00; (2) 11:00 and 12:00; (3) 15:00 and 16:00 and (4) 19:00 and 20:00. RESULTS: A significant decrease in BH during the day was observed in both standing and sitting positions (p< 0.001). The highest decrease in height was observed between the measurements performed between 7:00 and 8:00 and measurements carried out in the evening (19:00-20:00). For standing, the mean loss of height was 0.7 cm (± 0.7), i.e. 0.43% of initial standing height, for sitting the mean decrease in height was 0.7 cm (± 0.7), i.e. 0.79% of initial sitting height. CONCLUSIONS: BH decreases in children with IS during daytime. Due to diurnal BH variation, the time of the day should be recorded when measuring patients with IS.

Non-structural misalignments of body posture in the sagittal plane.

BACKGROUND: The physiological sagittal spinal curvature represents a typical feature of good body posture in the sagittal plane. The cervical and the lumbar spine are curved anteriorly (lordosis), while the thoracic segment is curved posteriorly (kyphosis). The pelvis is inclined anteriorly, and the lower limbs' joints remain in a neutral position. However, there are many deviations from the optimal body alignment.The aim of this paper is to present the most common types of non-structural misalignments of the body posture in the sagittal plane. MAIN BODY OF THE ABSTRACT: The most common types of non-structural misalignments of body posture in the sagittal plane are as follows: (1) lordotic, (2) kyphotic, (3) flat-back, and (4) sway-back postures. Each one may influence both the skeletal and the muscular system leading to the functional disturbance and an increased strain of the supporting structures. Usually, the disturbances localized within the muscles are analyzed in respect to their shortening or lengthening. However, according to suggestions presented in the literature, when the muscles responsible for maintaining good body posture (the so-called stabilizers) are not being stimulated to resist against gravity for an extended period of time, e.g., during prolonged sitting, their stabilizing function is disturbed by the hypoactivity reaction resulting in muscular weakness. The deficit of the locomotor system stability triggers a compensatory mechanism-the stabilizing function is overtaken by the so-called mobilizing muscles. However, as a side effect, such compensation leads to the increased activity of mobilizers (hyperactivity) and decreased flexibility, which may finally lead to the pathological chain of reaction within the musculoskeletal system. CONCLUSIONS: There exist four principal types of non-structural body posture misalignments in the sagittal plane: lordotic posture, kyphotic posture, flat-back posture, and sway-back posture. Each of them can disturb the physiological loading of the musculoskeletal system in a specific way, which may lead to a functional disorder.When planning postural corrective exercises, not only the analysis of muscles in respect to their shortening and lengthening but also their hypoactivity and hyperactivity should be considered.

Cobb angle measurements on digital radiographs using Bunnell scoliometer: Validation of the method.

BACKGROUND: Electronic rulers on computer screen are used to measure the Cobb angle (CA) instead of traditional methods with rulers, protractors and pens. The variety of software used to assess radiographs might make the CA measurements cumbersome in everyday clinical practice. OBJECTIVE: The aim of the study was to verify the method of CA measurements on digital radiographs using Bunnell scoliometer (BS). METHODS: Eighty patients with idiopathic scoliosis were enrolled into the study. CA of each curve was measured by use of Centricity software and BS. CA on 30 randomly chosen patients were measured 3 times by one researcher using only scoliometer. Three researchers measured CA on the same 30 radiographs using BS. RESULTS: The mean CA of 224 curves measured by Centricity and BS were 29° ± 12.2° and 28° ± 11.7°, respectively. The ICC for agreement for 2 methods was 0.96 with SEM of 1.7°. Excellent intra- and interobserver reliability of CA measurements with scoliometer was noted: ICC of 0.96 with SEM of 1.4° and ICC of 0.93 with SEM of 1.9°, respectively. CONCLUSIONS: The study revealed excellent reliability of CA measurements on digital radiographs using the BS. The proposed method of using the Bunnell scoliometer for CA measurements may be clinically useful.

Clinical and Radiographic Results of Indirect Decompression and Posterior Cervical Fusion for Single-Level Cervical Radiculopathy Using an Expandable Implant with 2-Year Follow-Up.

Background Indirect posterior cervical nerve root decompression and fusion performed by placing bilateral posterior cervical cages in the facet joints from a posterior approach has been proposed as an option to treat select patients with cervical radiculopathy. The purpose of this study was to report 2-year clinical and radiologic results of this treatment method. Methods Patients who failed nonsurgical management for single-level cervical radiculopathy were recruited. Surgical treatment involved a posterior approach with decortication of the lateral mass and facet joint at the treated level followed by placement of the DTRAX Expandable Cage (Providence Medical Technology, Lafayette, California, United States) into both facet joints. Iliac crest bone autograft was mixed with demineralized bone matrix and used in all cases. The Neck Disability Index (NDI), visual analog scale (VAS) for neck and arm pain, and SF-12 v.2 questionnaire were evaluated preoperatively and 2 years postoperatively. Segmental (treated level) and overall C2-C7 cervical lordosis, disk height, adjacent segment degeneration, and fusion were assessed on computed tomography scans and radiographs acquired preoperatively and 2 years postoperatively. Results Overall, 53 of 60 enrolled patients were available at 2-year follow-up. There were 35 females and 18 males with a mean age of 53 years (range: 40-75 years). The operated level was C3-C4 (N = 3), C4-C5 (N = 6), C5-C6 (N = 36), and C6-C7 (N = 8). The mean preoperative and 2-year scores were NDI: 32.3 versus 9.1 (p < 0.0001); VAS Neck Pain: 7.4 versus 2.6 (p < 0.0001); VAS Arm Pain: 7.4 versus 2.6 (p < 0.0001); SF-12 Physical Component Summary: 34.6 versus 43.6 (p < 0.0001), and SF-12 Mental Component Summary: 40.8 versus 51.4 (p < 0.0001). No significant changes in overall or segmental lordosis were noted after surgery. Radiographic fusion rate was 98.1%. There was no device failure, implant lucency, or surgical reinterventions. Conclusions Indirect decompression and posterior cervical fusion using an expandable intervertebral cage may be an effective tissue-sparing option in select patients with single-level cervical radiculopathy.

Influence of lower limbs discrepancy and pelvic coronal rotation on pelvic incidence, pelvic tilt and sacral slope.

PURPOSE: Pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS) are important parameters in sagittal spine alignment evaluation. The measurements are a projection of the three-dimensional pelvis onto a two-dimensional radiograph and they may be influenced by orientation of the pelvis. The aim of this study was to assess the influence of pelvic rotation in the coronal plane (CPR) on radiographic accuracy of PI, PT, and SS measurements. METHODS: Radiological evaluation of the CPR angel was performed on 1 radiological phantom. The radiographs were taken in 5° CPR increments over a range of 0°-45° (evaluated with a digital protractor). On each of the lateral radiograph, PI, PT, and SS were measured three times by three independent researchers. The lowest CPR that changed PI, PT, or SS by ≥6° (the highest reported error of measurement of these parameters) was considered as unacceptable. Next, CPR was calculated based on the distance between femoral heads (FHD). The agreement of the calculated and measured CPR was quantified by the intraclass correlation coefficient (ICC) and the median error for a single measurement (SEM), with value 0.75 considered as excellent agreement. RESULTS: PI, PT and SS could be measured with an acceptable error of 6° on radiographs with up to 20° pelvic rotation. From 20° CPR onwards the S1 endplate was distorted, that makes the measurements of PI, PT and SS questionable. There was an excellent agreement between CPR measured with a protractor and calculated based on FHD with ICC of 0.99 and SEM of 1.1°. CONCLUSIONS: Rotation of the pelvis in the coronal plane during acquisition of radiographs influences PI, PT and SS measurements. Substantial error of PI, PT and SS measurements occurs with CPR of more than 20° which is equivalent to a lower limb discrepancy of 5.2 cm. CPR may be calculated while acquiring the radiograph. Further evaluation of the influence of CPR on spinopelvic parameters with a larger sample would be valuable.

Pathophysiology of Minimally Invasive Surgical Approaches: Current Concepts.

Spine surgery is a continuously evolving field. Traditional posterior midline approaches to the lumbar spine are associated with muscle injury. Common mechanisms of injury include ischemia, denervation, and mechanical disruption of tendinous attachments of lumbar muscles. Muscle injury may be documented with chemical markers (creatinine kinase, aldolase, proinflammatory cytokines), by imaging studies, or with muscle biopsy. Minimally disruptive surgical approaches to the spine have the potential to minimize the trauma to muscular structures and thus improve the outcomes of surgery. The impact of minimally invasive spinal surgery on long-term clinical outcomes remains unknown. State-of-the-art pathophysiology of minimally invasive spine surgery is presented in this review.

Reliability of cervical lordosis measurement techniques on long-cassette radiographs.

PURPOSE: Lateral radiographs are commonly used to assess cervical sagittal alignment. Three assessment methods have been described and are commonly utilized in clinical practice. These methods are described for perfect lateral cervical radiographs, however in everyday practice radiograph quality varies. The aim of this study was to compare the reliability and reproducibility of 3 cervical lordosis (CL) measurement methods. METHODS: Forty-four standing lateral radiographs were randomly chosen from a lateral long-cassette radiograph database. Measurements of CL were performed with: Cobb method C2-C7 (CM), C2-C7 posterior tangent method (PTM), sum of posterior tangent method for each segment (SPTM). Three independent orthopaedic surgeons measured CL using the three methods on 44 lateral radiographs. One researcher used the three methods to measured CL three times at 4-week time intervals. Agreement between the methods as well as their intra- and interobserver reliability were tested and quantified by intraclass correlation coefficient (ICC) and median error for a single measurement (SEM). ICC of 0.75 or more reflected an excellent agreement/reliability. The results were compared with repeated ANOVA test, with p < 0.05 considered as significant. RESULTS: All methods revealed excellent intra- and interobserver reliability. Agreement (ICC, SEM) between three methods was (0.89°, 3.44°), between CM and SPTM was (0.82°, 4.42°), between CM and PTM was (0.80°, 4.80°) and between PTM and SPTM was (0.99°, 1.10°). Mean values CL for a CM, PTM, SPTM were 10.5° ± 13.9°, 17.5° ± 15.6° and 17.7° ± 15.9° (p < 0.0001), respectively. The significant difference was between CM vs PTM (p < 0.0001) and CM vs SPTM (p < 0.0001), but not between PTM vs SPTM (p > 0.05). CONCLUSIONS: All three methods appeared to be highly reliable. Although, high agreement between all measurement methods was shown, we do not recommend using Cobb measurement method interchangeably with PTM or SPTM within a single study as this could lead to error, whereas, such a comparison between tangent methods can be considered.

Cervical Sagittal Alignment in Scheuermann Disease.

STUDY DESIGN: Retrospective evaluation of radiographs. OBJECTIVE: The aim of this study was to assess sagittal cervical balance in patients with the two types Scheuermann disease (SD). SUMMARY OF BACKGROUND DATA: The structural hyperkyphosis characterizing SD may be localized in the thoracic (SDT) or thoraco-lumbar (SDTL) spine segments. This may affect sagittal cervical balance. METHODS: Seventy-one patients (41 males and 30 females), aged 16.3 ±â€Š3.8 years with SD, were enrolled into the study. On standing lateral long-cassette radiographs, the following measurements were made: C0-2 angle, C2-7 angle (CL), C1-C2 angle, relative rotation angle (RRA)-measured at levels from C2 to C7, cervical tilt (CT), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), C0-angle, cranial offset (CO), and cranial tilt (CRT). Comparison with t test was performed with significance level P < 0.05. RESULTS: There were 38 SDT and 33 SDTL patients. In SDT, the T1 slope was significantly greater than that in SDTL (38.1° vs. 28.9°; P = 0.0002), and consequently CL (-19.8° vs. -8.9°; P = 0.0160), CT (29.8° vs. 24.3°; P = 0.0190), and TIA (81.9° vs. 71.1°; P = 0.0022) in SDT were significantly greater as well. The difference in CL was expressed mainly in C6-C5 (-4.8° vs. -1.4°; P = 0.0146) and C5-C4 (-4.4°; vs. -1.5° P = 0.0464) segments. There were no significant differences in proximal cervical lordosis: C0-2 angle (-21.6° vs. -20.8°; P = 0.7597), C1-C2 angle (-30.8°vs. -27.5°; P = 0.1746), C3-C2 (-5.4° vs. -5.1°; P = 0.7976), and C4-C3 (3.5° vs. -1.5°; P = 0.1464) segments. There was no significant difference in cranial parameters C0-angle, CRT, and CO. CONCLUSION: Scheuermann disease type has an influence on cervical sagittal balance. Localization of structural kyphosis affects the T1 slope as well as C2-C7 lordosis, cervical tilt, and thoracic inlet angle. Significant difference in C2-C7 lordosis in comparison to similar C0-2 lordosis demonstrates that compensation is present in subaxial cervical spine. Position of the head center of gravity is not dependent on the SD type. LEVEL OF EVIDENCE: 4.

Influence of cervical spine position on the radiographic parameters of the thoracic inlet alignment.

PURPOSE: Cervical sagittal balance is a complex phenomenon, influenced by many factors, which cannot be described by cervical lordosis alone. Attention has been focused on the relationship between T1 slope, thoracic inlet angle, and cervical sagittal balance. However, the effect of cervical position on these parameters has not been evaluated yet. The aim of this study was to assess the influence of cervical flexion and extension on radiographic thoracic inlet parameters. METHODS: 60 patients with one level radiculopathy symptoms underwent radiological examination. Mean age was 53 (40-72) years; there were 24 males and 34 females. Lateral standing X-rays of cervical spine were taken on the same day in neutral position, full flexion and full extension. Patients with previous cervical operations or congenital malformations were excluded. Thoracic inlet angle (TIA), neck tilt (NT) and thoracic (T1) slope were measured. Agreement between measurements was assessed and quantified by intra-class correlation coefficient (ICC) and median error for a single measurement (SEM). The ICC value greater than 0.75 reflected sufficient agreement. RESULTS: The mean values of the parameters were: (1) for the neutral position: TIA 71.7° ± 9.5°; T1 slope 26.7° ± 6.3°; and NT 44.9° ± 7.2°, (2) In extension: TIA 71.8° ± 9.4°; T1 slope 24.9° ± 7.6°; and NT 46.9° ± 7.2° and (3) In flexion 78.3° ± 10.3°; T1 slope 33.6° ± 7.8°; and NT 44.7° ± 7.4°. An excellent agreement was revealed for all NT measurements (ICC 0.76) and for TIA measured in flexion and neutral position (ICC 0.79). There was insufficient overall and in-pairs agreement for T1 slope measurements. CONCLUSIONS: Neck tilt measurements were not influenced by position of the cervical spine. T1 slope was significantly influenced by flexion and extension of the neck. This puts the concept that TIA is a morphologic parameter into question. This information should be taken into consideration when analyzing lateral radiographs of the cervical spine for clinical decision-making.