Positional relationship between the Achilles tendon and sural nerve on ultrasound.

PURPOSE: This study sought to clarify the positional relationship between the Achilles tendon and sural nerve using ultrasound. METHODS: We studied 176 legs in 88 healthy volunteers. The positional relationship between the Achilles tendon and sural nerve at heights of 2, 4, 6, 8, 10, and 12 cm proximal from the calcaneus' proximal margin was investigated by distance and depth. Setting the X-axis (left/right) as the horizontal axis and Y-axis (depth) as the vertical axis against ultrasound images, we investigated the distance between the lateral margin of the Achilles tendon to the midpoint of the sural nerve on the X-axis. The Y-axis was split into four zones: the part behind the center of the Achilles tendon (AS), the part in front of the center of the Achilles tendon (AD), the part behind the Achilles tendon (S), and the part in front (D). We investigated the zones through which the sural nerve passed. We also studied any significant differences between the sexes and left/right legs. RESULTS: The mean distance on the X-axis was closest at 6 cm, with 1.1 ± 5.0 mm between them. The sural nerve's position on the Y-axis was such that at positions more proximal than 8 cm, the sural nerve ran through zone S in most legs and moved to zone AS through heights 2-6 cm. No parameters showed significant differences between the sexes or left/right legs. CONCLUSION: We presented the positional relationship between the Achilles tendon and sural nerve and suggested some measures to prevent nerve injury during surgery.

Recompression of Augmented Vertebrae after Balloon Kyphoplasty Is a Risk of Adjacent Vertebral Fracture.

Introduction: This study aimed to identify factors associated with adjacent vertebral fracture (AVF) incidence after balloon kyphoplasty (BKP). Methods: To perform the analyses, 133 vertebrae of 128 patients who underwent BKP for osteoporotic vertebral compression fracture were retrospectively investigated. According to the presence of AVF throughout a 1-year period following BKP, patients were divided into AVF (n = 22) and non-AVF (n = 111) groups. The groups were compared with respect to pre- and postoperative parameters, including the incidence of recompression of augmented vertebrae (RAV). RAV was defined as a decrease in anterior vertebral body height of at least 5 mm within the 3 months that followed BKP. To identify factors associated with AVF incidence, univariate and multivariate analyses were performed. Results: The univariate analysis revealed that the AVF group had a lower cement augmentation ratio, greater preoperative wedge angle, lower preoperative vertebral body height, lower postoperative vertebral body height 3 months post-BKP, and a greater change in vertebral body height and rate of RAV than the non-AVF group. Multivariate analysis revealed that low preoperative vertebral body height and RAV occurrence were associated with AVF incidence. Conclusions: To the best of our knowledge, this study is the first to indicate that RAV is a risk factor for AVF. Study findings indicate that the incidence of AVF can be decreased if RAV development is avoided.

Insufficient Augmentation of Bone Cement Causes Recompression of Augmented Vertebra after Balloon Kyphoplasty.

INTRODUCTION: Balloon kyphoplasty (BKP) is one of the most frequently used clinical methods to relieve pain caused by osteoporotic vertebral compression fracture (OVCF); it can effectively improve the body height of the vertebra. However, recompression of the augmented vertebra (RAV) is often observed after BKP. This study aimed to report factors that are associated with RAV in terms of cement augmentation. METHODS: A total of 78 patients (women, 60; men, 18) were included in this study. RAV was defined as anterior vertebral height loss (VHL), between immediate postoperation and 3 or 6 months after BKP, of more than 5.0 mm. Cement augmentation ratio (CAR) was calculated as the ratio of the maximal height of polymethylmethacrylate (PMMA) to the maximal distance between both end plates. Age, gender, fracture age, CAR, presence of medication for osteoporosis, intervertebral cleft (IVC), and cement leakage were evaluated using Fisher's exact test or Mann-Whitney U test to compare between RAV and non-RAV groups. Aforementioned variables were also analyzed using multiple logistic regression test. A P<0.05 was considered statistically significant. RESULTS: The incidence rates for RAV at 3 and 6 months were 35.9% (28/78) and 38.5% (30/78), respectively. Age (80.1 vs 74.7) was significantly higher in the RAV group, whereas CAR (69.4% vs 77.6%) was lower in the non-RAV group. A multivariate regression analysis revealed that age (odds ratio (OR)=1.12, P=0.001) and CAR (OR=0.91, P=0.001) were independently associated with RAV. CONCLUSIONS: RAV was observed in 38.5% of patients in this study. Older age and low CAR were independently associated with RAV. To prevent RAV, especially in the elderly, augmented PMMA should come in contact with both end plates.

Simultaneous-onset infectious spondylitis with vertebral fracture mimicking an acute osteoporotic vertebral fracture erroneously treated with balloon kyphoplasty: illustrative case.

BACKGROUND: Early balloon kyphoplasty (BKP) intervention for acute osteoporotic vertebral fracture (OVF) has been reported to be more effective than the conservative treatment. However, complications of early BKP intervention are still unknown. OBSERVATIONS: A 71-year-old patient with OVF of L2 underwent BKP 2 weeks after symptom onset. Preoperative magnetic resonance imaging (MRI) and radiograph were compatible with new L2 OVF. Although computed tomography (CT) images revealed the atypical destruction of lower endplate of L2 as OVF, L2 BKP was planned. After BKP, his back pain improved dramatically. Two weeks after BKP, his lower back pain recurred. MRI and CT confirmed the diagnosis of infectious spondylitis with paravertebral abscess formation. With adequate antibiotic treatment and rehabilitation, he was symptom-free and completely ambulatory without signs of infection. LESSONS: Signal changes on the fractured vertebral bodies during initial MRI and fractured vertebral instability on radiograph can mislead the surgeon to interpret the infection as a benign compression fracture. If the patients exhibit unusual destruction of the endplate on CT imaging, "simultaneous-onset" spondylitis with vertebral fracture should be included in the differential diagnosis. To determine the strategy for OVF, preoperative biopsy is recommended if simultaneous-onset spondylitis with vertebral fracture is suspected.