Sacroiliac Joint Variation in Patients With Ossification of the Posterior Longitudinal Ligament

Study Design: Retrospective Cohort Study. Objectives: Ossification of the posterior longitudinal ligament (OPLL) reveals heterotopic ossification in the spinal ligament. OPLL also tends to ossify ligaments and entheses throughout the body. However, hallmarks of sacroiliac (SI) joint ossification and its variation in OPLL have not been clarified. Here, we investigated the morphological changes in SI joints in individuals with and without OPLL. Methods: We included 240 age- and sex-matched patients (OPLL+, 120; OPLL−, 120) in the study. SI joint variations were classified into 4 types: Type 1, normal or small peripheral bone irregularity; Type 2, subchondral bone sclerosis and osteophyte formation; Type 3, vacuum phenomenon; and Type 4, bridging osteophyte and bony fusion. Type 4 was further divided into 3 subgroups as previously described. Interactions between the ossified spinal region in OPLL and morphological changes in the SI joint were evaluated. Results: SI joint ankylosis occurs more frequently in patients with OPLL (51.7%) than in those without (non-OPLL) (33.3%). The SI joint vacuum phenomenon (49.2%) was the main finding in non-OPLL. SI joint ankylosis in OPLL was characterized by anterior bridging and intra-articular fusion. OPLL patients with multilevel ossification tend to develop degeneration and ankylosis of the SI joints. Conclusions: OPLL conferred a high risk of SI joint ossification compared with non-OPLL, and patients with extensive ossification had a higher rate of SI joint ankylosis. Understanding SI joint variation could help elucidate OPLL etiology and clarify the phenotypic differences in the SI joint between OPLL and other spinal disorders.

Osteochondral Lesions of the Talus May Cause the Vacuum Phenomenon in the Ankle Joint

The few reports available on the vacuum phenomenon in the ankle joint refer to osteoarthritic and traumatic lesions. We present the first case concomitant with an osteochondral lesion of the talus. This case report presents computed tomographic images of the ankle. We speculate that the osteochondral lesion of the talus was the most likely cause of the vacuum phenomenon.

Vacuum Phenomenon As A Predictor of Kyphosis After Implant Removal Following Posterior Pedicle Screw Fixation Without Fusion For Thoracolumbar Burst Fracture: A Single-Center Retrospective Study

Background: Posterior pedicle screw fixation without fusion has been commonly applied for thoracolumbar burst fracture. Implant removal is performed secondarily after bone union. However, the occurrence of secondary kyphosis has recently attracted attention. Secondary kyphosis results in poor clinical outcomes. The purpose of this was to determine predictors of kyphosis after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture.Methods: This retrospective study reviewed 60 consecutive patients with thoracolumbar burst fracture who underwent implant removal following posterior pedicle screw fixation without fusion. Inclusion criteria were non-osteoporotic fracture and T11-L4 burst fracture. Old age, sex, initial severe wedge deformity, initial severe kyphosis, and vacuum phenomenon were examined as factors potentially associated with final kyphotic deformity (defined as kyphotic angle greater than 25°) or loss of correction. Logistic regression analysis was performed using propensity score matching.Results: Among the 31 female and 29 male patients (mean age 39 years), final kyphotic deformity was found in 17 cases (28%). Multivariate analysis showed a significant association with the vacuum phenomenon. Loss of correction was found in 35 cases (58%) and showed a significant association with the vacuum phenomenon. There were no significant associations with other factors.Conclusions: The findings of this study suggest that the vacuum phenomenon before implant removal may be a predictor of secondary kyphosis of greater than 25° after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture, but that old age, sex, initial severe kyphosis, and initial severe wedge deformity may not be predictors.

Vacuum Phenomenon as a Predictor of Kyphosis After Implant Removal Following Posterior Pedicle Screw Fixation Without Fusion for Thoracolumbar Burst Fracture: a Single-center Retrospective Study

Background: Posterior pedicle screw fixation without fusion has been commonly applied for thoracolumbar burst fracture. Implant removal is performed secondarily after bone union. However, the occurrence of secondary kyphosis has recently attracted attention. Secondary kyphosis results in poor clinical outcomes. The purpose of this was to determine predictors of kyphosis after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture.Methods: This retrospective study reviewed 60 consecutive patients with thoracolumbar burst fracture who underwent implant removal following posterior pedicle screw fixation without fusion. Inclusion criteria were non-osteoporotic fracture and T11-L4 burst fracture. Old age, sex, initial severe wedge deformity, initial severe kyphosis, and vacuum phenomenon were examined as factors potentially associated with final kyphotic deformity (defined as kyphotic angle greater than 25°) or loss of correction. Logistic regression analysis was performed using propensity score matching.Results: Among the 31 female and 29 male patients (mean age 39 years), final kyphotic deformity was found in 17 cases (28%). Multivariate analysis showed a significant association with the vacuum phenomenon. Loss of correction was found in 35 cases (58%) and showed a significant association with the vacuum phenomenon. There were no significant associations with other factors.Conclusions: The findings of this study suggest that the vacuum phenomenon before implant removal may be a predictor of secondary kyphosis of greater than 25° after implant removal following posterior pedicle screw fixation without fusion for thoracolumbar burst fracture, but that old age, sex, initial severe kyphosis, and initial severe wedge deformity may not be predictors.

Vacuum Phenomenon in the Lumbar Spine: A Useful Tool for Neuroradiologists and Spine Surgeons?

The vacuum phenomenon in the lumbar spine is a common finding on radiographs and CT imaging. Its presence has been known for more than a century and has been increasing in spine literature during the past 20 years. Although once thought of as an incidental finding, further research may yield important findings about the vacuum phenomenon, which may allow radiologists to understand its meaning more clearly when it is encountered.Learning Objective: The goal of this article is to present the reader with a better understanding of the vacuum phenomenon as it pertains to the lumbar spine and with its history in radiology and surgery literature, its presence in recent literature, and how it may impact spine radiology and surgery moving forward.

Pneumorrhachis causing cauda equina syndrome: a case report and literature review

Background Pneumorrhachis (PR) describes the rare presence of intraspinal air, mainly following traumatic or iatrogenic procedures. According to the localization of air in the spinal canal, PR has been classified into internal (subdural) and external (epidural). PR rarely manifests in neurological deficits and usually resolves spontaneously without recurrence, with air being passed directly into the bloodstream. Here, we report a case of external PR occurring spontaneously (without any underlying trauma or surgical interventions) manifesting as neurological deficits. This is an extremely rare finding with only a limited number of cases in the literature. Case presentation We report a case of spontaneous external PR manifesting as neurological symptoms in a 62-year-old male diabetic patient with chronic low backpain who developed numbness in his perineal region mainly on the left side. His medical history was normal, without trauma or surgical intervention. Magnetic resonance imaging (MRI) and computed tomography (CT) in the past 2 years demonstrated degenerative changes in the lumbar spine, including end plates and disc spaces, with intervertebral disc vacuum phenomenon (VP); the CT additionally showed intraspinal air in the epidural space at L5-S1 levels compressing the cauda equina. A diagnosis of spontaneous external PR was made. A follow-up MRI upon exacerbation of neurological deficits showed an increase in air locule size. Our patient was managed conservatively on a nonsteroidal anti-inflammatory agent (NSAID) and was advised for regular follow-ups. No aspiration or surgery has been performed to date. Conclusions Spontaneous external pneumorrhachis manifesting as neurological symptoms is extremely rare. Due to degenerative disc disease producing vacuum phenomenon, we propose that spontaneous PR secondary to intradiscal VP be considered as part of the differential for radicular symptoms, especially with increasing age. The most effective noninvasive investigation for the diagnosis of PR is CT. MRI is less beneficial in the case of PR as gas and calcifications are hard to distinguish, both being of low-intensity signals on all MR sequences.