Upper Thoracic Compensation against Global Malalignment and Spinopelvic Mismatch in Adult Spinal Deformity Patients Analyzed Using the EOS Imaging System.

Introduction: Patients with adult spinal deformity (ASD) develop compensatory mechanisms. The Cobb angle between T4 and T12 has been used as a standard to define thoracic kyphosis (TK) because radiological evaluation is difficult in upper thoracic region. The upper thoracic compensatory mechanism has not been sufficiently explored, and focal thoracic compensation remains poorly understood. This study aimed to determine upper sagittal thoracic compensation and features of thoracic compensation in ASD patients. Methods: The records of 218 consecutive patients who underwent full-standing EOS imaging were retrospectively examined. Spinopelvic parameters-including the T1-T12, T4-T12, T1-T4, T5-T8, and T9-T12 angles-were measured using a dedicated and validated software. The relationship between the thoracic and spinopelvic parameters was statistically evaluated. Thoracic compensation was compared among four typical types of spinal deformity. Results: A total of 127 ASD patients met the inclusion criteria. TK(1-12) was negatively correlated with the sagittal vertical axis (SVA) (r=-0.35), T1 pelvic angle (TPA) (r=-0.29), and pelvic incidence minus lumbar lordosis (PI-LL) (r=-0.60). TK(1-4) showed a stronger correlation with the SVA and TPA than TK(5-8) or TK(9-12) (r=-0.39, -0.38, respectively). TK(1-4), TK(5-8), and TK(9-12) had a similar negative correlation with PI-LL; however, TK(5-8) had the strongest correlation (r=-0.38). Both age and TK(9-12) were significantly associated with decreased TK(1-4), and vertebral fracture was significantly associated with increased TK(9-12). Both patients with high SVA and those in the hyperthoracic kyphosis group had lower TK(1-4) angles. Conclusions: In ASD patients, upper thoracic spine compensation plays an important role in countering global malalignment. The middle part of the thoracic spine has a strong correlation with LL. This study findings can help clinicians better manage ASD patients.

Correlation between leg pain at rest and spinal nerve edema in symptomatic lumbar foraminal stenosis.

BACKGROUND: Previous studies reported that spinal nerve edema on magnetic resonance myelography (MRM) and leg pain at rest were specifically observed in symptomatic lumbar foraminal stenosis patients. However, the correlation between leg pain at rest and spinal nerve edema in symptomatic foraminal stenosis has not been reported. HYPOTHESIS: The purpose of this prospective study is to reveal a correlation between leg pain at rest and spinal nerve edema focusing on the pathophysiology of symptomatic foraminal stenosis. PATIENTS AND METHODS: Clinical findings and MRM findings were surveyed among 30 patients with symptomatic foraminal stenosis diagnosed by MR imaging (MRI) and selective nerve root block. Comparisons of patient characteristics and clinical findings between the prevalence and absence groups of spinal nerve edema on MRM were analyzed. A correlation between the visual analogue scale (VAS) for leg pain at rest and the spinal edema ratio calculated as maximum intensity value of the affected spinal nerve/maximum intensity value of the asymptomatic side from region of interest (ROI) made on MRM was evaluated. RESULTS: Twenty symptomatic foraminal stenosis cases (67%) showed the affected spinal nerve edema on MRM. The prevalence and VAS of leg pain at rest were significantly higher in the presence of spinal nerve edema group (95% and 67.0±36.4, respectively). The correlation coefficient between the VAS for leg pain at rest (53.0±33.6) and the spinal nerve edema ratio (1.3±0.3) was 0.647 (p<0.01). DISCUSSION: Our study revealed the substantial correlation found between the spinal nerve edema ratio on MRM and the VAS for leg pain at rest in symptomatic foraminal stenosis. The correlation between spinal nerve edema and leg pain at rest has potential to clarify the pathology of symptomatic foraminal stenosis. LEVEL OF EVIDENCE: IV.

Characteristic Reconstitution of the Spinal Langerhans Cell Histiocytosis in Young Children.

BACKGROUND: Pediatric Langerhans cell histiocytosis (LCH) often results in vertebral compression fracture. However, few reports have reported vertebral remodeling during the course of LCH. We aimed to investigate the longitudinal reconstitution and transformation of the affected vertebrae and the adjacent structures in young children with spinal LCH. METHODS: We recruited 13 patients, including 16 affected vertebrae, diagnosed with LCH via biopsy. The average age at first visit was 3.6 years. The average follow-up period was 10.2 years. Vertebral lesions involved L2 in 3 cases; T12, L1, or L5 in 2 cases; and C4, C5, C7, T5, T8, T9, or L3 in 1 case. We measured the ratios of the height of the affected vertebra and 1 vertebra above the affected one to that of the second vertebra above the affected one, local kyphotic angles, and the ratio of the height of the center of the adjacent disk to that of one disk above it. RESULTS: The collapse of the affected vertebra was most severe after 1 year of disease onset. The rate of reconstitution accelerated at 2 years or later of disease onset. The recovery speed of the anterior wall was faster than that of the center height. While the height of the affected vertebrae was restored, the thickness of the adjacent disk also increased. Further, the height of the adjacent vertebrae increased in a similar manner. The average local kyphosis angle shifted to lordosis within the first 3 years. CONCLUSIONS: The heights of not only the disk but also the adjacent vertebra increased during the vertebral collapse phase in pediatric spinal LCH patients. These transformations may affect the realignment of the sagittal spinal balance at the earlier stage of the disease. During the collapse phase, the heights of the adjacent vertebrae and disks increase but after the affected vertebrae reconstituted, the augmentation of adjacent vertebrae and disks diminished. LEVEL OF EVIDENCE: Level IV.

Surgical Intervention for Osteoporotic Vertebral Burst Fractures in Middle-low Lumbar Spine with Special Reference to Postoperative Complications Affecting Surgical Outcomes.

The purpose of this study was to investigate the clinical and radiological features of osteoporotic burst fractures affecting levels below the second lumbar (middle-low lumbar) vertebrae, and to clarify the appropriate surgical procedure to avoid postoperative complications. Thirty-eight consecutive patients (nine male, 29 female; mean age: 74.8 years; range: 60-86 years) with burst fractures affecting the middle-low lumbar vertebrae who underwent posterior-instrumented fusion were included. Using the Magerl classification system, these fractures were classified into three types: 16 patients with superior incomplete burst fracture (superior-type), 11 patients with inferior incomplete burst fracture (inferior-type) and 11 patients with complete burst fracture (complete-type). The clinical features were investigated for each type, and postoperative complications such as postoperative vertebral collapse (PVC) and instrumentation failure were assessed after a mean follow-up period of 3.1 years (range: 1-8.1 years). All patients suffered from severe leg pain by radiculopathy, except one with superior-type fracture who exhibited cauda equina syndrome. Nineteen of 27 patients with superior- or inferior-type fracture were found to have spondylolisthesis due to segmental instability. Although postoperative neurological status improved significantly, lumbar lordosis and segmental lordosis at the fused level deteriorated from the postoperative period to the final follow-up due to postoperative complications caused mainly by PVC (29%) and instrument failure (37%). Posterior-instrumented fusion led to a good clinical outcome; however, a higher incidence of postoperative complications due to bone fragility was inevitable. Therefore, short-segment instrument and fusion with some augumentation techniqus, together with strong osteoporotic medications may be required to avoid such complications.

Minodronate treatment improves low bone mass and reduces progressive thoracic scoliosis in a mouse model of adolescent idiopathic scoliosis.

Recent studies have shown an association between osteopenia and adolescent idiopathic scoliosis (AIS) and implied that osteopenia plays a causative role in AIS development. This study aimed to determine if minodronate (MIN) treatment could prevent curve progression by increasing bone mass in a thoracic restraint (TR) mouse model, which develops causes the development of thoracic scoliosis similar to human AIS. A total of 100 young female C57BL6J mice were divided into four groups: (1) control with vehicle (CON/VEH; n = 20), (2) control with MIN (CON/MIN; n = 20), (3) TR with vehicle (TR/VEH; n = 30), or (4) TR with MIN (TR/MIN; n = 30). MIN (0.01 mg/kg/week) and vehicle were administered intraperitoneally to their respective groups. TR was performed at age 4 weeks, and the mice were sacrificed at age 9 weeks. Body weights, spine radiographs, femoral bone mineral density (BMD), serum bone marker levels, and histomorphometry of the cancellous bone of the thoracic vertebrae were analyzed. TR significantly reduced weight gain in the TR/VEH group relative to the CON/VEH group. TR also induced osteoporosis with accelerated bone resorption, as indicated by decreases in femoral BMDs and thoracic cancellous bone volume and increases in serum bone resorption marker levels and histomorphometric resorption parameters in the TR/VEH group. MIN partially improved body weight gain and improved poor bone structure relative to the TR/VEH group by suppressing high bone resorption in the TR/MIN mice. MIN significantly reduced the curve magnitudes, as indicated by a 43% lower curve magnitude in the TR/MIN mice than in the TR/VEH mice (17.9 ± 8.9° vs. 31.5 ± 13.1°; p< 0.001). The administration of MIN increased bone mass and reduced the severity of scoliosis in the TR mice. MIN was suggested as a possible inhibitor of scoliosis development.

Evaluation of functional and structural leg length discrepancy in patients with adolescent idiopathic scoliosis using the EOS imaging system: a prospective comparative study.

BACKGROUND: To our knowledge, no studies have reported the exact structural leg length discrepancies (LLDs) in patients with adolescent idiopathic scoliosis (AIS). Therefore, this study aimed to evaluate the differences between functional and structural LLDs and to examine the correlations between LLDs and spinopelvic parameters in patients with AIS using an EOS imaging system, which permits the three-dimensional reconstruction of spinal and lower-limb bony structures. METHODS: Eighty-two consecutive patients with AIS underwent whole-body EOS radiography in a standing position between August 2014 and March 2016. Functional LLD, lumbar Cobb angle, thoracic curve Cobb angle, coronal balance, and pelvic obliquity were measured using two-dimensional EOS radiography. Structural LLDs were measured using three-dimensional EOS-reconstructed images. The comparison between LLDs was assessed using paired t test. Pearson's correlation coefficient (r) was used to determine potential correlations between the LLDs and spinopelvic alignment parameters. RESULTS: Functional LLDs were significantly larger than structural LLDs (5.6 ± 5.0 vs. 0.2 ± 3.6 mm, respectively; p < 0.001). Both functional and structural LLDs were significantly correlated with pelvic obliquity (r = 0.69 and r = 0.51, respectively; p < 0.001 for both). Functional LLD, but not structural LLD, was correlated with lumbar Cobb angle (r = 0.44, p < 0.001; r = 0.17, p = 0.12, respectively). In addition, functional and structural LLDs were not correlated with thoracic Cobb angle (r = 0.09 and r = - 0.05, respectively; p ≥ 0.68 for both). CONCLUSIONS: Although patients with AIS often have functional LLDs, structural LLDs tend to be smaller. The correlation between functional LLDs and the lumbar Cobb angle indicates that functional LLDs compensate for the lumbar curve. Thus, the difference between functional and structural LLDs indicates a compensatory mechanism involving extension and flexion of the lower limbs.

Spondylolysis repair using a pedicle screw hook or claw-hook system. -a comparison of bone fusion rates.

INTRODUCTION: To assess the bone fusion rates and clinical results of two surgical methods (pedicle screw claw-hook fixation and pedicle screw hook fixation) of lumbar spondylolysis repair. METHODS: A multicenter database of surgical patients with lumbar spondylolysis was reviewed. All patients < 20 years old with a minimum of 6 months of follow-up and computed tomography images were included. Operation time and blood loss amount were investigated. Visual analogue scale (VAS; 0-10) scores for lower back pain were evaluated to assess clinical results. RESULTS: A total of 17 patients met the inclusion criteria. Pedicle screw hook fixation was performed in five patients (the hook group), and pedicle screw claw-hook fixation was performed in 13 patients (the claw-hook group). One patient was included in both groups because each method was performed at different lumbar levels (L4 and L5). The bone fusion rates at 3, 6, and 9 months after surgery were significantly higher in the claw-hook group than those in the hook group. Operation time and blood loss amount were not significantly different between the groups. VAS scores improved in the claw-hook group but not in the hook group because of a small number of patients. CONCLUSIONS: Pedicle screw claw-hook fixation was more effective than pedicle screw hook fixation in terms of bone fusion rates.

Anatomical etiology of "pseudo-sciatica" from superior cluneal nerve entrapment: a laboratory investigation.

OBJECTIVE: The superior cluneal nerve (SCN) may become entrapped where it pierces the thoracolumbar fascia over the iliac crest; this can cause low back pain (LBP) and referred pain radiating into the posterior thigh, calf, and occasionally the foot, producing the condition known as "pseudo-sciatica." Because the SCN was thought to be a cutaneous branch of the lumbar dorsal rami, originating from the dorsal roots of L1-L3, previous anatomical studies failed to explain why SCN causes "pseudo-sciatica". The purpose of the present anatomical study was to better elucidate the anatomy and improve the understanding of "pseudo-sciatica" from SCN entrapment. MATERIALS AND METHODS: SCN branches were dissected from their origin to termination in subcutaneous tissue in 16 cadavers (5 male and 11 female) with a mean death age of 88 years (range 81-101 years). Special attention was paid to identify SCNs from their emergence from nerve roots and passage through the fascial attachment to the iliac crest. RESULTS: Eighty-one SCN branches were identified originating from T12 to L5 nerve roots with 13 branches passing through the osteofibrous tunnel. These 13 branches originated from L3 (two sides), L4 (six sides), and L5 (five sides). Ten of the 13 branches showed macroscopic entrapment in the tunnel. CONCLUSION: The majority of SCNs at risk of nerve entrapment originated from the lower lumbar nerve. These anatomical results may explain why patients with SCN entrapment often evince leg pain or tingling that mimics sciatica.

Anatomical study of middle cluneal nerve entrapment.

OBJECT: Entrapment of the middle cluneal nerve (MCN) under the long posterior sacroiliac ligament (LPSL) is a possible, and underdiagnosed, cause of low-back and/or leg symptoms. To date, detailed anatomical studies of MCN entrapment are few. The purpose of this study was to ascertain, using cadavers, the relationship between the MCN and LPSL and to investigate MCN entrapment. METHODS: A total of 30 hemipelves from 20 cadaveric donors (15 female, 5 male) designated for education or research, were studied by gross anatomical dissection. The age range of the donors at death was 71-101 years with a mean of 88 years. Branches of the MCN were identified under or over the gluteus maximus fascia caudal to the posterior superior iliac spine (PSIS) and traced laterally as far as their finest ramification. Special attention was paid to the relationship between the MCN and LPSL. The distance from the branch of the MCN to the PSIS and to the midline and the diameter of the MCN were measured. RESULTS: A total of 64 MCN branches were identified in the 30 hemipelves. Of 64 branches, 10 (16%) penetrated the LPSL. The average cephalocaudal distance from the PSIS to where the MCN penetrated the LPSL was 28.5±11.2 mm (9.1-53.7 mm). The distance from the midline was 36.0±6.4 mm (23.5-45.2 mm). The diameter of the MCN branch traversing the LPSL averaged 1.6±0.5 mm (0.5-3.1 mm). Four of the 10 branches penetrating the LPSL had obvious constriction under the ligament. CONCLUSION: This is the first anatomical study illustrating MCN entrapment. It is likely that MCN entrapment is not a rare clinical entity.

A histomorphometric study of the cancellous spinal process bone in adolescent idiopathic scoliosis.

PURPOSE: Adolescent idiopathic scoliosis (AIS) is a three-dimensional deformity with increased risk of osteopenia of unknown etiology. This study examined the dynamic histomorphometry of AIS patients to gain insight into the underlying pathogenesis of bone metabolism changes in AIS. METHODS: Bone histomorphometry of the spinous process of the 12th thoracic vertebra was analyzed in 33 AIS patients and compared to age-matched normative data. Patients were classified into bone turnover subgroups, based on bone formation rate. RESULTS: Bone volume was subnormal in 67% of AIS patients, but normal in 33%. Bone turnover was high in 76% of the patients, normal in 9%, and low in 15%. Compared to those in the low-turnover group, the high-turnover group patients were taller and had higher TRAP5b values. CONCLUSIONS: Bone histomorphometry indicated that bone fragility and abnormal bone turnover were common in AIS patients. These abnormalities might contribute to the poor bone status and etiology in AIS.

Scoliosis surgery for handicapped children.

INTRODUCTION: This study aimed to assess treatment outcomes and caregivers' satisfaction regarding scoliosis surgery for handicapped children. METHODS: Handicapped children are, by definition, noncommunicatory and/or nonambulatory. We recruited 26 handicapped children who were followed-up for >1 year after a scoliosis surgery. We recruited 40 patients with adolescent idiopathic scoliosis (AIS) who underwent a surgery during the same period as controls. We used a posterior approach in all the children. We determined preoperative body mass index (BMI), main Cobb angle, Cincinnati correction index (CCI), and fusion level; intraoperative time and blood loss per level; and postoperative complications. We also assessed caregivers' satisfaction with surgical treatments for these patients using the modified Bridwell's questionnaire. RESULTS: We have described the results as handicapped children/AIS. Median preoperative BMI was 16.1/18.6 kg/m2. Preoperative and final Cobb angles were 94.2°/59.7° and 39.7°/17.0°, respectively and CCI was 2.0/1.7. The number of fusion levels was 14.6/9.0. The operative time and blood loss per level were 40.1/44.1 minutes and 264/138 ml, respectively. Postoperative complications in handicapped children were adynamic ileus in 8 cases, dysphagia in 5, pneumonia in 3, urinary tract infection in 2, and superior mesenteric artery syndrome (SMA), surgical site deep infection, infectious enteritis, agitation, and liver dysfunction in 1 each. However, in the AIS group, there was only 1 case of SMA. Median caregivers' satisfaction score on the 0-10 visual analog scale was 9. Caregivers for 19 of the 26 handicapped cases (73%) recommended surgical treatment to caregivers of other children with the same disease. CONCLUSIONS: Surgical treatment for neuromuscular and syndromic scoliosis was associated with a high rate of postoperative complications. However, the caregivers' satisfaction score after surgery was high.

A Japanese nationwide multicenter survey on perioperative complications of corrective fusion for elderly patients with adult spinal deformity.

BACKGROUND: Recently, corrective fusion surgery for patients with adult spinal deformity (ASD) has become common in Japan. This study aimed to clarify the status of surgeries for ASD in Japan, focusing on perioperative complications. A nationwide multicenter survey gathering information on surgically treated ASD patients was conducted by the committee for Adult Spinal Deformity of the Japanese Scoliosis Society. METHODS: This study was a review of retrospectively collected data from 18 spine scoliosis centers belonging to the Japanese Scoliosis Society. Patients who underwent corrective fusion surgery for ASD between 2011 and 2013 were included. Demographics, comorbidities, surgical data, and complications were investigated. RESULTS: A total of 1192 patients (mean age, 57.7 years) were included in this study. Of these, 611 patients were aged less than 65 years and 581 patients were aged 65 years or greater. The age distribution had two peaks, in the third and eighth decades. Deformities caused by degeneration represented 67% of the pathology in patients aged over 65 years; however, non-degenerative disease such as adult idiopathic scoliosis and syndromic or congenital deformity represented over 60% of pathology in patients aged less than 65 years. The iatrogenic deformity and reoperation rates were both less than 3%. The mean operation time and estimated blood loss were 370 min and 1642 ml, respectively. Major perioperative complications occurred in 160 patients (14.5%). The incidence of complications was significantly higher in patients aged over 65 years, including neurological deficits, hemorrhagic shock, hematoma, heart failure, and surgical site infection (p < 0.05). CONCLUSIONS: Older (aged over 65 years) ASD patients showed greater rates of deformity due to the occurrence of degeneration and vertebral fractures, as well as a higher incidence of peri-and postoperative complications. Efforts to reduce perioperative complications are therefore imperative, especially for elderly ASD patients in our aging society.

Laminar screw fixation in the subaxial cervical spine: A report on three cases.

Although laminar screw fixation is often used at the C2 and C7 levels, only few previous case reports have presented the use of laminar screws at the C3-C6 levels. Here, we report a novel fixation method involving the use of practical laminar screws in the subaxial spine. We used laminar screws in the subaxial cervical spine in two cases to prevent vertebral artery injury and in one case to minimize exposure of the lamina. This laminar screw technique was successful in all three cases with adequate spinal rigidity, which was achieved without complications. The use of laminar screws in the subaxial cervical spine is a useful option for posterior fusion of the cervical spine.

Validation study of arm positions for evaluation of global spinal balance in EOS imaging.

BACKGROUND: The sagittal vertical axis (SVA) is important in the evaluation of spinal sagittal balance. Although the "fists-on-clavicles" (FOC) position has been widely used in radiographic examinations, it does not define shoulder flexion in detail. Meanwhile, in EOS imaging, the "hands-on-cheeks" (HOC) position is widely used but has not been well investigated. The purpose of this study was to investigate the relative usefulness of FOC and HOC in investigating SVA. MATERIALS AND METHODS: Mean SVA was measured by EOS imaging using standing lateral radiographs of 34 volunteers in four different positions: relaxed (RLX), shoulder flexion at 90° with FOC (FOC90), elbows touching the trunk with FOC (FOCET), and HOC. RESULTS: The mean SVA was 2.0 ± 2.1 cm in RLX; -1.4 ± 3.2 cm in FOC90; -0.5 ± 3.0 cm in FOCET; and -0.2 ± 2.9 cm in HOC. The negative shift from RLX was significantly greater in FOC90 than in FOCET (-3.4 ± 2.2 vs -2.5 ± 2.4 cm; p = 0.0182). The negative shift from RLX in HOC was almost equal to that in FOCET; the difference was 0.3 cm (-2.2 ± 2.2 vs -2.5 ± 2.4 cm; p = 0.2560). CONCLUSION: FOC90 showed a negative SVA shift in comparison with FOCET. The difference in the mean SVA between HOC and FOCET was 0.3 cm, a clinically small difference.

Entrapment of middle cluneal nerves as an unknown cause of low back pain.

Entrapment of middle cluneal nerves induces low back pain and leg symptoms. The middle cluneal nerves can become spontaneously entrapped where this nerve pass under the long posterior sacroiliac ligament. A case of severe low back pain, which was completely treated by release of the middle cluneal nerve, was presented. Entrapment of middle cluneal nerves is possibly underdiagnosed cause of low-back and/or leg symptoms. Spinal surgeons should be aware of this clinical entity and avoid unnecessary spinal surgeries and sacroiliac fusion. This paper is to draw attention by pain clinicians in this unrecognized etiology.

Retraction Note: Relationship between bone density and bone metabolism in adolescent idiopathic scoliosis.

[This retracts the article DOI: 10.1186/s13013-015-0043-x.].

Relationship between bone density and bone metabolism in adolescent idiopathic scoliosis.

Several authors have confirmed that 27 to 38 % of AIS patients had osteopenia. But few studies have assessed bone metabolism in AIS. This study assessed bone mineral density and bone metabolism in AIS patients using the bone metabolism markers, BAP and TRAP5b. The subjects were 49 consecutive adolescent AIS patients seen at our institutes between March 2012 and September 2013. Sixty-five percent of AIS patients had osteopenia or osteoporosis and 59 % of AIS patients had high values for TRAP5b. The AIS patients with high values of TRAP5b had lower Z scores than those with normal values of TRAP5b. Higher rates of bone resorption are associated with low bone density in AIS patients.

Relationship between bone density and bone metabolism in adolescent idiopathic scoliosis.

Several authors have confirmed that 27 to 38% of AIS patients had osteopenia. But few studies have assessed bone metabolism in AIS. This study assessed bone mineral density and bone metabolism in AIS patients using the bone metabolism markers, BAP and TRAP5b. The subjects were 49 consecutive adolescent AIS patients seen at our institutes between March 2012 and September 2013. Sixty-five percent of AIS patients had osteopenia or osteoporosis and 59% of AIS patients had high values for TRAP5b. The AIS patients with high values of TRAP5b had lower Z scores than those with normal values of TRAP5b. Higher rates of bone resorption are associated with low bone density in AIS patients.

Accuracies in Measuring Spinopelvic Parameters in Full-Spine Lateral Standing Radiograph.

STUDY DESIGN: Prospective comparative study of measuring pelvic incidence (PI) among standing radiographs of whole spine and pelvis and computed tomographic (CT) scans in a cohort of patients. OBJECTIVE: To analyze accuracies in measuring PI and other spinopelvic parameters. SUMMARY OF BACKGROUND DATA: Previous reports indicated relatively low agreement in measuring PI even among experienced spinal surgeons; intra- and inter-rater reliability in manually measuring PI were 0.69 (0.62-0.74) and 0.41 (0.36-0.45), respectively; the mean interclass correlation coefficient value of manually measuring PI was 0.881. No study compared PI on standing radiographs with that measured on CT scans. METHODS: A total of 120 consecutive patients with spinal disease (38 patients had history of hip arthroplasty) who admitted to our hospital from April 2012 for 6 months were enrolled. Subjects had obtained full-spine lateral standing radiograph, standing radiograph of pelvis, and CT scans. Pelvic incidence on full-spine lateral standing radiograph and that on pelvis lateral standing radiograph were measured manually by 2 experienced spinal surgeons. Intra- and interobserver reliability of the measurements were analyzed by using interclass correlation coefficient. On CT scans, PI was measured using 3-dimensional CT scan software (CT-PI). PI among 3 different imaging modalities was evaluated using correlation coefficients. RESULTS: In whole-spine radiographs, the intra- and interobserver agreement rates with measurements in PI (0.84 and 0.79, respectively) and sacral slope (0.87 and 0.83, respectively) were lower than those in pelvic tilt (0.98 and 0.96, respectively) and PI-lumbar lordosis (0.97 and 0.97, respectively). The correlation coefficient between P-PI and CT-PI was higher (0.95) than that between FS-PI and CT-PI (0.81) and between FS-PI and P-PI (0.85). CONCLUSION: The reliability of measuring PI is comparatively lower than that of other spinopelvic parameters, and the variability of PI measurement is mainly due to difficulty of precisely identifying sacral endplate. LEVEL OF EVIDENCE: 2.

Roentgenographic and computed tomographic findings in symptomatic lumbar foraminal stenosis.

PURPOSE: To determine the static and dynamic radiological findings characteristic of symptomatic foraminal stenosis. METHODS: Between 2006 and 2011, a total of 114 patients with unilateral leg pain due to L5 nerve root compression were screened to investigate the characteristic radiological findings of symptomatic foraminal stenosis. Static findings on sagittal CT images and dynamic findings on X-rays were compared between 39 surgically treated L5-S1 foraminal stenosis patients (FS group) and 75 surgically treated L4-5 intra-spinal canal stenosis patients (CS group). RESULTS: There was no significant difference between the FS and CS groups in all demographic data and radiologic findings, except for the segmental range of motion in sagittal plane on functional X-rays and posterior translation on extension. The segmental range of motion in sagittal plane at L5-S1 was significantly larger in the FS group (13.4 ± 3.1 vs. 4.2 ± 2.0; p = 0.03) compared to the CS group. The prevalence of 3 mm or more posterior translation at L5 was significantly higher in the FS group (38 vs. 3%; p = 0.04) compared to the CS group, and the average posterior translation of L5 was significantly greater in the FS group (3.1 ± 1.6 mm) than that in the CS group (0.3 ± 0.6 mm) (p = 0.02). CONCLUSIONS: A large segmental range of motion in sagittal plane of L5-S1 and posterior instability of L5 are risk factors for symptomatic L5-S1 foraminal stenosis. These dynamic radiological findings support the diagnosis of symptomatic foraminal stenosis.