Anatomy of the L5 nerve root in the pelvis for safe sacral screw placement: a cadaveric study.

OBJECTIVE: Previous reports have focused on the complications of L5 nerve root injury caused by anterolateral misplacement of the S1 pedicle screws. Anatomical knowledge of the L5 nerve root in the pelvis is essential for safe and effective placement of the sacral screw. This cadaveric study aimed to investigate the course of the L5 nerve root in the pelvis and to clarify a safe zone for inserting the sacral screw. METHODS: Fifty-four L5 nerve roots located bilaterally in 27 formalin-fixed cadavers were studied. The ventral rami of the L5 nerve roots were dissected along their courses from the intervertebral foramina to the lesser pelvis. The running angles of the L5 nerve roots from the centerline were measured in the coronal plane. In addition, the distances from the ala of the sacrum to the L5 nerve roots were measured in the sagittal plane. RESULTS: The authors found that the running angles of the L5 nerve roots changed at the most anterior surface of the ala of the sacrum. The angles of the bilateral L5 nerve roots from the right and left L5 intervertebral foramina to their inflection points were 13.77° ± 5.01° and 14.65° ± 4.71°, respectively. The angles of the bilateral L5 nerve roots from the right and left inflection points to the lesser pelvis were 19.66° ± 6.40° and 20.58° ± 5.78°, respectively. There were no significant differences between the angles measured in the right and left nerve roots. The majority of the L5 nerves coursed outward after changing their angles at the inflection point. The distances from the ala of the sacrum to the L5 nerve roots in the sagittal plane were less than 1 mm in all cases, which indicated that the L5 nerve roots were positioned close to the ala of the sacrum and had poor mobility. CONCLUSIONS: All of the L5 nerve roots coursed outward after exiting the intervertebral foramina and never inward. To prevent iatrogenic L5 nerve root injury, surgeons should insert the S1 pedicle screw medially with an angle > 0° toward the inside of the S1 anterior foramina and the sacral alar screw laterally with an angle > 30°.

Osteoporosis and Osteoporotic Vertebral Fractures: Breaking the Chain of Osteoporotic Fractures to Increase Healthy Life Expectancy.

Osteoporosis is an important issue related to life expectancy and healthy life expectancy in Japan, where the super-aging population is growing. Currently, in Japan, some kind of assistance is needed for an average of 10 years at the end of life. In many cases the reason assistance is needed is loss of mobility due to a fracture caused by a fall. When people suffer one fracture due to osteoporosis, they are also more likely to have another fracture, which is called a secondary fracture. Breaking the negative chain of fractures is very important in osteoporosis. In addition, if patients suffer a loss of mobility due to a compression fracture of the spine, this activity cannot be regained even if the fracture is healed. To prevent this from happening, it is also important to heal fractures rapidly, so that patients can quickly return to normal life, thus extending healthy life expectancy.

L5 nerve root injury caused by anterolateral malpositioning of loosened S1 pedicle screws: illustrative cases.

BACKGROUND: Although malpositioning of pedicle screws into the spinal canal and intervertebral foramen can cause spinal nerve root injuries, there are few reports of L5 nerve root injuries when S1 pedicle screws have been inserted anterolaterally. The authors report two cases of L5 nerve root injury caused by anterolateral malpositioning of loosened S1 pedicle screws. OBSERVATIONS: In both patients, S1 pedicle screws were inserted toward the outside of the S1 anterior foramen, and the tip of the screws perforated the anterior sacral cortex. L5 nerve root impairment was not observed immediately after surgery. However, severe leg pain in the L5 area was observed after the S1 pedicle screws became loosened. In case 1, the symptoms could not be controlled with conservative treatment. Reoperation was performed 3 months after the initial surgery. In case 2, the symptoms gradually improved with conservative treatment because the area around the loosened S1 screw was surrounded by newly formed bone that stabilized the screws, as observed with computed tomography 1 year after surgery. LESSONS: Surgeons should recognize that anterolateral malpositioning of S1 pedicle screws can cause L5 nerve root injury. The screws should be inserted in the correct direction without loosening.

Novel Hump Measurement System With a 3D Camera for Early Diagnosis of Patients With Adolescent Idiopathic Scoliosis: A Study of Accuracy and Reliability.

Background Adolescent idiopathic scoliosis (AIS) is a potentially progressive deformity, and early detection is crucial for timely intervention. However, the methods and criteria justifying screening for pediatric scoliosis remain controversial. We have, therefore, independently developed a Digital Moiré (DM) as a tool for scoliosis screening. The purpose of this study was to assess the usefulness of DM for scoliosis screening. Methods From March 2016 to March 2017, 126 patients (18 boys, 108 girls, mean age: 13.2 ± 2.2 years) with AIS underwent radiographic imaging of their whole spine. We tested the accuracy and reliability of DM by categorizing the examination results as Class 0 (no abnormality), Class 1 (return visit in one year), and Class 2 (further examination needed) and determined the distribution of the population by Cobb angle. The intra/inter-rater reliability and receiver operating characteristic (ROC) analyses were used to categorize the patients with positive findings into Class 1 or 2. Results Regarding the population distribution per Cobb angle in each of the distributions, 11 patients (8.7%) were Class 0, of which nine and two patients had Cobb angle ≤ 10 ° and > 10 °, respectively. There were 20 (15.9% ) Class 1 cases, of which 17 and three had Cobb angle ≤ 10 ° and > 10 °, respectively. Of the 95 (75.4%) Class 2 cases, five and 90 had a Cobb angle of ≤ 10 ° and > 10 °, respectively. The receiver operating characteristic (ROC) analysis of patients with positive findings showed that the area under the curve (AUC), sensitivity, specificity, and false-positive rate were 0.76, 0.98, 0.53, and 0.47, respectively, when predicting Cobb angle > 10°. Intra-rater and inter-rater reliability were 0.73 and 0.70, respectively. Conclusions This study demonstrated the usefulness of DM for determining whether a child with AIS requires a follow-up observation such as radiograph. Our findings suggest that the novel DM shows high accuracy and reliability for scoliosis screening.

Postoperative Clinical Outcomes of Balloon Kyphoplasty Treatment: Would Adherence to Indications and Contraindications Prevent Complications?

STUDY DESIGN: We retrospectively assessed the postoperative clinical outcomes of balloon kyphoplasty (BKP). PURPOSE: To evaluate the risk factors for complications and to reconfirm the indications and contraindications for BKP. OVERVIEW OF LITERATURE: In Japan, BKP is indicated for cases of osteoporotic vertebral fractures when pain is not improved even after an adequate period of conservative treatment. Contraindications to BKP include pedicle fracture, fracture of a flat vertebra, or fracture of the posterior wall of the vertebral body diagnosed on computed tomography. METHODS: Seventy-five patients who underwent BKP in our institution participated in this study; 49 provided follow-up data. Those with complications and persistent pain were assigned to the "eventful" group; the others, to the "uneventful" group. We evaluated risk factors for complications and persistent pain, including the presence or absence of severe posterior wall injury/pedicle fracture, the shape of the vertebral body, and the time period from onset of pain to BKP. RESULTS: The incidences of severe posterior wall injury, pedicle fracture, and flattened vertebral body did not differ significantly between the uneventful and eventful groups. However, there was a significant difference in disease duration between those with and those without adjacent vertebral fractures (AVFs): The incidence of AVF was lower among patients with disease of less than 8 weeks' duration. CONCLUSIONS: Disease duration is a possible risk factor for developing AVF, whereas other characteristics were not risk factors for complications after BKP. Although it has been suggested that BKP treatment in the early phase after injury results in a good outcome, the indications should be determined according to prognosis that is based on findings obtained with tools such as imaging examinations.

New classification focusing on implant designs useful for setting therapeutic strategy for periprosthetic femoral fractures.

PURPOSE: In periprosthetic femoral fractures, our hypothesis was that when the bone and implant are stable, the fracture does not occur at the biologic or cement fixation regions but occurs at the no fixation region. The aim of this study was to investigate the validity of our new classification for periprosthetic femoral fractures and compare reliability of radiographic evaluation for implant stability between our classification and the Vancouver classification. PATIENTS AND METHODS: Sixty-six patients with periprosthetic femoral fracture were operatively treated by us between 2005 and 2013. We investigated the sensitivity and specificity of our new classification with actual implant stability. Twenty patients were randomly selected from 66 patients. After fully explaining the Vancouver and our new classification to four orthopaedic surgeons, plain radiographs acquired in two directions at the time of injury were presented, and the interobserver reliability based on the two classifications and accuracy rates of stem stability were investigated. RESULTS: The specificity of the new classification was 89%, and sensitivity was 94%. The positive and negative predictive values were 84% and 96%, respectively. Interobserver agreement was separately assessed among all possible pairs of orthopaedic surgeons. The κ values for the Vancouver and the new classification were 0.36 (0.19-0.49) and 0.76 (0.66-1.0), respectively. CONCLUSIONS: Our classification is based on a completely new concept and was prepared to overcome periprosthetic femoral fracture failures by objective evaluation. We believe this new classification is useful to establish a therapeutic strategy for femoral fractures around the stem.

Evaluation of the effect of glucosamine administration on biomarkers of cartilage and bone metabolism in bicycle racers.

In the present study, the effect of glucosamine administration (1.5 or 3 g/day) on cartilage and bone metabolism was investigated in bicycle racers, using cartilage­ and bone­specific biomarkers, including C­terminal cross­linked telopeptides of type II collagen (CTX­II), C­terminal propeptides of type II procollagen (CPII), N­terminal telopeptides of bone­specific type I collagen (NTx) and bone alkaline phosphatase (BAP). The results indicate that CPII (a marker of type II collagen synthesis) was not substantially changed, however, CTX­II (a marker of type II degradation) was reduced by glucosamine administration, particularly at a dose of 3 g/day. Consistent with these observations, the ratio of CTX­II/CPII was reduced by glucosamine administration and the effect of glucosamine was dose­dependent. By contrast, the levels of NTx (a bone resorption marker) and BAP (a bone formation marker) were not altered by glucosamine administration. A previous study by this group reported that glucosamine exerts a chondroprotective action in soccer players by preventing type II collagen degradation but maintaining type II collagen synthesis. Together these observations indicate that glucosamine may exert a chondroprotective action by preventing type II collagen degradation in athletes of various sports, including soccer players and bicycle racers.

Retrodental mass in rheumatoid arthritis.

STUDY DESIGN: A retrospective investigation of the retrodental mass secondary to rheumatoid arthritis (RA). OBJECTIVE: To propose a new classification of the retrodental mass in RA, and to evaluate their resorption processes and surgical procedures. SUMMARY OF BACKGROUND DATA: The retrodental mass secondary to RA has long been recognized as pannus formation. It is also known that pannus will disappear or radically reduce after stabilization of the atlantoaxial segment. The past reports, however, leave unanswered the following question; are there other types of mass with significantly different degeneration processes from the pannus? The need for anterior transoral decompression is still controversial. METHODS: Eleven patients with retrodental masses in RA were retrospectively analyzed. They underwent posterior fusion without decompression for atlantoaxial subluxation and occipitocervical fusion with decompressive laminectomy of the atlas for vertical subluxation. All patients had neurological, radiologic, and magnetic resonance imaging (MRI) evaluations both before and after surgery. MRI study was performed preoperatively and at 1-month interval after surgery until the mass had disappeared or stopped further reduction. RESULTS: This study identified 3 distinctive types in the rheumatoid retrodental mass on MRI. Type 1 displayed high intensity on T2 and low intensity on T1-weighted MRI or the pattern specific to pannus. Type 2 was identified with low intensity on T2-weighted MRI or pattern specific to pseudotumor. Type 3 displayed a combination of high and low intensity on T2-weighted images or indication that the mass was the mixture of pannus and pseudotumor. All the masses of types 1 and 3 disappeared within 1 month of surgery. The process in type 2 was found a few months slower. In all 11 cases, myelopathy improved postoperatively to the status before the emergence of the symptom. CONCLUSIONS: This article recognized 3 distinctive types of the retrodental mass in RA; type 1 (pannus), type 2 (pseudotumor), type 3 (mixed). It further concludes in all types of the retrodental mass associated with atlantoaxial subluxation secondary to RA, posterior fusion without decompression can achieve improvement of the myelopathy. In type 2 associated with vertical subluxation, on balance between calculable benefits and high risks of anterior transoral decompression, the authors prefer to opt for occipitocervical fusion with decompressive laminectomy of the atlas.

Evaluation of the effect of a chicken comb extract-containing supplement on cartilage and bone metabolism in athletes.

In a previous study, we revealed that a commercially available product of dietary supplement containing a chicken comb extract (CCE), which is rich in hyaluronan, not only relieves joint pain and other symptoms, but also potentially improves the balance of type II collagen degradation/synthesis in patients with knee osteoarthritis. Since soccer is one of the sports most likely to cause knee osteoarthritis (OA), we evaluated the effect of a CCE-containing supplement on cartilage and bone metabolism in athletes. Fourteen and 15 subjects (all midfielders) were randomly assigned to receive the test product (test group) and the dummy placebo containing only vehicle (placebo group), respectively, for 12 weeks. The daily oral intake of the CCE-containing test product clearly decreased the urinary levels of both C-terminal crosslinked telopeptides of cartilage-specific type II collagen (CTX-II) as a type II collagen degradation marker and the N-terminal telopeptides of bone-specific type I collagen (NTx) as a marker of bone resorption at 12 weeks after the initiation of the intervention. By contrast, no significant reduction was detected in the placebo group at any timepoint during the intervention. These observations indicate that the test product is effective in inhibiting, not only cartilage degradation, but also bone remodeling. Thus, the CCE-containing supplement may be useful for the management of joint health in athletes.