Development of a Deep Learning Model for Diagnosing Lumbar Spinal Stenosis Based on CT Images

STUDY DESIGN

Retrospective study.

OBJECTIVES

This study aimed to develop an initial deep learning model based on CT scans for diagnosing lumbar spinal stenosis.

SUMMARY OF BACKGROUND DATA

MRI is commonly used for diagnosing lumbar spinal stenosis due to its high soft tissue resolution, but CT is more portable, cost-effective, and has wider regional coverage. Using deep learning models to improve the accuracy of CT diagnosis can effectively reduce missed diagnoses and misdiagnoses in clinical practice.

METHODS

Axial lumbar spine CT scans obtained between March 2022 and September 2023 were included. The dataset was divided into a training set (62.3%), a validation set (22.9%), and a control set (14.8%). All data were labeled by two spine surgeons using the widely accepted grading system for lumbar spinal stenosis. The training and validation sets were used to annotate the ROIs by the two spine surgeons. First, an ROI detection model and a CNN classifier were trained using the training set. After training, the model was preliminarily evaluated using a validation set. Finally, the performance of the deep learning model was evaluated on the control set, and a comparison was made between the model and classification performance of specialists with varying levels of experience.

RESULTS

The central stenosis grading accuracies of DL Model Version 1 and DL Model Version 2 were 88% and 83%, respectively. The lateral recess grading accuracies of DL Model Version 1 and DL Model Version 2 were 75% and 71%, respectively.

CONCLUSIONS

Our preliminarily developed deep learning system for assessing the degree of lumbar spinal stenosis in CT, including the central canal and lateral recess, has shown similar accuracy to experienced specialist physicians. This holds great value for further development and clinical application.

Complications and radiographic changes after implantation of interspinous process devices: average eight-year follow-up

PURPOSE

This study aims to evaluate complications, clinical outcomes, and radiographic results following Coflex implantation.

METHODS

We retrospectively studied 66 patients who had decompressive surgery combined with Coflex implantation to treat lumbar spinal stenosis. All imaging data were collected and examined for imaging changes. Clinical outcomes, included Oswestry Disability Index (ODI), back and leg visual analog scale (VAS) scores, were evaluated before surgery, six months after surgery and at the last follow-up. The number of complications occurring after five years of follow-up was counted. All reoperation cases were meticulously recorded.

RESULTS

66 patients were followed up for 5-14 years. The VAS and ODI scores were significantly improved compared with baseline. Heterotopic Ossification (HO) was detectable in 59 (89.4%). 26 (39.4%) patients had osteolysis at the contact site of Coflex with the spinous process. Coflex loosening was detected in 39 (60%) patients. Spinous process anastomosis was found in 34 (51.5%) patients. There was a statistically significant difference in the VAS score of back pain between patients with and without spinous process anastomosis. Nine cases of lumbar spinal restenosis were observed, and prosthesis fracture was observed in one case.

CONCLUSION

Our study identified various imaging changes after Coflex implantation, and majority of them did not affect clinical outcomes. The majority of patients had HO, but osteolysis and Coflex loosening were relatively rare. The VAS score for back pain of these patients was higher if they have spinous process anastomosis. After five-year follow-up, we found lumbar spinal restenosis and prosthesis fracture cases.

Safranal inhibits estrogen-deficiency osteoporosis by targeting Sirt1 to interfere with NF-κB acetylation

BACKGROUND

Osteoporosis is a prevalent bone metabolic disease in menopause, and long-term medication is accompanied by serious side effects. Estrogen deficiency-mediated hyperactivated osteoclasts is the initiating factor for bone loss, which is regulated by nuclear factor-κB (NF-κB) signaling. Safranal (Saf) is a monoterpene aldehyde produced from Saffron (Crocus sativus L.) and possesses multiple biological properties, particularly the anti-inflammatory property. However, Saf's role in osteoporosis remains unknown.

PURPOSE

This study aims to validate the role of Saf in osteoporosis and explore the potential mechanism.

STUDY DESIGN

The RANKL-exposed mouse BMM (bone marrow monocytes) and the castration-mediated osteoporosis model were applied to explore the effect and mechanism of Saf in vitro and in vivo.

METHOD

The effect of Saf on osteoclast formation and function were assessed by TRAcP staining, bone-resorptive experiment, qPCR, immunoblotting and immunofluorescence, etc. Micro-CT, HE, TRAcP and immunohistochemical staining were performed to estimate the effects of Saf administration on OVX-mediated osteoporosis in mice at imaging and histological levels.

RESULTS

Saf concentration-dependently inhibited RANKL-mediated osteoclast differentiation without affecting cellular viability. Meanwhile, Saf-mediated anti-osteolytic capacity and Sirt1 upregulation were also found in ovariectomized mice. Mechanistically, Saf interfered with NF-κB signaling by activating Sirt1 to increase p65 deacetylation and inactivating IKK to decrease IκBα degradation.

CONCLUSION

Our results support the potential application of Saf as a therapeutic agent for osteoporosis.

Inhibition of EZH2 ameliorates cartilage endplate degeneration and attenuates the progression of intervertebral disc degeneration via demethylation of Sox-9

Background

Cartilaginous endplate (CEP) degeneration is considered as one of the major causes of intervertebral disc degeneration (IVDD) which causes low back pain. Recent studies have proved that epigenetic alteration is involved in a variety of diseases. This work explored the role of histone methyltransferase enhancer of zeste homologue 2 (EZH2) in CEP degeneration, as well as its underlying epigenetic mechanisms, and confirmed the effect of EZH2 knockdown on delaying IVDD development.

Methods

Western blotting, immunofluorescence staining, and ChIP assay were applied to demonstrate the molecular mechanism of EZH2 in CEP tissue. The therapeutic potential of EZH2 was investigated using puncture-induced rat models.

Findings

The EZH2 expression was upregulated in human and rat CEP tissue. It was also found that the overexpression of EZH2 suppressed the expression of Collagen II, aggrecan and Sox-9, and promoted the expression of ADTAMTS5 and MMP13 in rat endplate chondrocytes (EPCs), which could be reversed by EZH2 silencing. The correlation between EZH2 and Sox-9 was further explored, while overexpression of Sox-9 could reverse the effect of EZH2 in rat EPCs. Moreover, inhibition of EZH2 upregulated the level of Sox-9 by demethylating H3K27me3 at Sox-9 promoter sites, revealing the regulatory mechanism of EZH2 on Sox-9. Meanwhile, puncture-induced rat models showed that EZH2 knockdown exerted a protective effect on CEP and disc degeneration.

Interpretation

This study reveals that EZH2 inhibition is a promising strategy for mitigating the symptoms and progression of IVDD.

Funding

: This study was funded by the Natural Science Foundation of Zhejiang Province (Y16H060034). Authors declare that the funders had no involvement in the study design, data analysis and interpretation of the results.

Projection of the Most Anterior Line of the Spinal Canal on Lateral Radiograph: An Anatomic Study for Percutaneous Kyphoplasty and Percutaneous Vertebroplasty

ABSTRACTPurpose: To measure the projection of the most anterior line of the spinal canal on lateral radiographs of the vertebra (C3-L5) and evaluate the efficacy of the safety line (SL) in preventing intraspinal cement leakage in percutaneous kyphoplasty (PKP) and percutaneous vertebroplasty (PVP). Materials and Methods: Fifteen adult dry-bone spine specimens were analyzed. The projection of the SL was viewed on lateral radiographs. The distance between the SL and the posterior vertebral body line (PVBL) was measured. Two groups of patients were treated by PKP, and cement injection was stopped either before the PBVL (group 1) or before the SL (group 2) under lateral fluoroscopy. The rate of cement leakage was compared between the two groups. Results: The largest distance between the SL and PVBL was at L1 (5.22 ± 0.62 mm). From L1 to L5, the distance decreased progressively to 1.05 ± 0.64 mm. Similar variation was also observed from L1 to T1 (0.19 ± 0.18 mm). The postoperative computed tomography scan was more sensitive and accurate in detecting intraspinal leakage than radiography in group 1 (p = 0.000); however, there was no significant difference in sensitivity or accuracy between methods in group 2 (p = 0.063). The rate of intraspinal cement leakage was significantly higher in group 1 than group 2 (p = 0.000). Conclusions: The operator should frequently check to ensure that cement injection has stopped upon reaching the SL. Surgeons may benefit from this quantitative anatomical study of PKP and PVP.

Cervical myelopathy caused by invaginated laminae of the axis associated with occipitalizaion of the atlas: Case report and literature review

RATIONALE

In previous studies, few cases of cervical myelopathy caused by invaginated anomalous laminae of the axis have been reported, and none of them was combined with occipitalization of the atlas.

PATIENT CONCERNS

A 28-year-old male was brought to our hospital with motor and sensory impairments of the extremities after a car accident.

DIAGNOSES

MRI showed the spinal cord was markedly compressed at the C2/3 level. Reconstructed CT scans revealed an invaginated laminae of axis into the spinal canal as well as atlas assimilation.

INTERVENTIONS

The patient was successfully managed with surgical treatment by removal of the anomalous osseous structure as well as fixation and fusion.

OUTCOMES

The patient had a rapid recovery after the operation. He regained the normal strength of his 4 extremities and the numbness of his extremities disappeared. He returned to his normal work 3 months after the surgery without any symptoms.

LESSONS

Invaginated laminae of axis combined with occipitalization of the atlas is a rare deformity. MRI and reconstructed CT scans are useful for both diagnosing and surgical planning of this case. Surgical removal of the laminae results in a satisfactory outcome. The pathogenesis of this anomaly could be the fusion sequence error of the 4 chondrification centers in the embryological term.

Cervical digit in a child: A case report

BACKGROUND

A "digit-like" bone is a rare developmental anomaly that is usually seen in the pelvic or thoracic regions. Such an anomaly in the cervical spine is extremely rare and few cases have been reported. We present a patient with an anomalous bone posterior to a cervical vertebra. The patient was admitted to our hospital with a gradually growing hard neck mass and esthetic complaints. Physical examination, radiographs, reconstructed computed tomography, and magnetic resonance imaging revealed a digit-like bone posterior to the cervical spine. The patient was diagnosed with a "cervical digit." Through a posterior midline approach, the anomalous bone was excised because of its gradually increasing size and esthetic complaints.

RESULTS

Intraoperatively, the bony mass was found to have a pseudoarticulation with the spinous process of C5 (the fifth cervical vertebra). The specimen consisted of normal bone and cartilage. The child returned to a normal life postoperatively with no symptoms. There was no recurrence at the 2-year follow-up.

CONCLUSION

A congenital cervical digit is a rare deformity. A detailed clinical workup and advanced imaging examinations are useful for diagnosing such conditions. Esthetic complaints contribute to surgical indications. This is the first cervical digit managed with surgical excision of the anomalous bone and had a favorable outcome.

Anterior endoscopically assisted bone grafting for iatrogenic distraction of odontoid fracture after percutaneous anterior screw fixation: A case report

RATIONALE

The complication of iatrogenic distraction of odontoid fracture after anterior screw fixation has not been reported in the literature. We treated the patient with endoscopically assisted bone grafting with good results. The new technique was not reported in the management of odontoid fracture or nonunion before.

PATIENT CONCERNS

A 22-year-old man presented with neck pain after a motorcycle crash. The cervical spine radiograph and computed tomographic scan demonstrated the base of dens displaced 2 mm anteriorly.

DIAGNOSES

Radiographic images showed a type II odontoid fracture.

INTERVENTIONS

The patient was treated by percutaneous anterior screw fixation. The postoperative radiograph and CT demonstrated an iatrogenic distraction of the odontoid with a gap of 6 mm.The follow-up radiograph did not show any sign of bone union 1 month and a half later. A revision surgery was given by anterior endoscopically assisted bone grafting. The patient was encouraged to sit out of bed immediately after the surgery with the protection of a soft cervical collar for 3 months.

OUTCOMES

No complications such as neural structures or vascular injuries were found. Bone union was achieved at the 1-year follow-up CT scans. Physical examination showed a full range of motion in the neck.

LESSONS

We reported a case of iatrogenic odontoid distraction that was managed by anterior endoscopically assisted bone grafting. It is a technically feasible and minimally invasive procedure.

The Spinal Cord Line Can Predict Postoperative Recovery for Multilevel Cervical Spondylotic Myelopathy

OBJECTIVE

To report a new index, the spinal cord (SC) line, and a new classification to predict postoperative recovery effect in patients with multilevel cervical spondylotic myelopathy (CSM).

METHODS

On T2-weighted magnetic resonance imaging (MRI) of the cervical spine, point A is the posteroinferior point of the spinal cord at C2, and point B is the posterosuperior point of the spinal cord at C7. The SC line is defined as a line connecting A and B. The posterior surface of the compressor at the compression level does not exceed the line in SC line type I, touches the line in type II, and exceeds the line in type III. Between January 2010 and January 2015, 121 patients with multilevel CSM who underwent surgery through an anterior approach (anterior cervical corpectomy with fusion or anterior cervical discectomy and fusion) or a posterior approach (laminoplasty or laminectomy) in our hospital were studied retrospectively. The patients were classified into 3 groups according to SC line type (I, II, or III).

RESULTS

In the anterior surgical approach group, the Japanese Orthopaedic Association (JOA) recovery rate at the last follow-up was 84.88 ± 3.06% for SC line type I, 78.05 ± 2.89% for type II, and 68.69 ± 3.21% for type III. In the posterior surgical approach group, the JOA recovery rate at last follow-up was 69.35 ± 8.73% for type I, 58.05 ± 5.88% for type II, and 47.98 ± 4.31% for type III. The anterior surgery approach was associated with a higher postoperative recovery rate than the posterior surgery approach in type II and type III groups (type II anterior vs. type II posterior: 78.05 ± 2.89% vs. 58.05 ± 5.88%, P = 0.003; type III anterior vs. type III posterior: 68.69 ± 3.21% vs. 47.98 ± 4.31%, P = 0.001). In contrast, the anterior and posterior surgery were associated with similar postoperative recovery rates in the type I group (84.88 ± 3.06% vs. 69.35 ± 8.73%; P = 0.820).

CONCLUSIONS

The SC line and its classifications can predict postoperative recovery in patients with multilevel CSM.

What is the optimal cutoff value of the axis-line-angle technique for evaluating trunk imbalance in coronal plane?

BACKGROUND CONTEXT

Accurately evaluating the extent of trunk imbalance in the coronal plane is significant for patients before and after treatment. We preliminarily practiced a new method, axis-line-angle technique (ALAT), for evaluating coronal trunk imbalance with excellent intra-observer and interobserver reliability. Radiologists and surgeons were encouraged to use this method in clinical practice. However, the optimal cutoff value of the ALAT for determination of the extent of coronal trunk imbalance has not been calculated up to now.

PURPOSE

The purpose of this study was to identify the cutoff value of the ALAT that best predicts a positive measurement point to assess coronal balance or imbalance.

STUDY DESIGN/SETTING

A retrospective study at a university affiliated hospital was carried out.

PATIENT SAMPLE

A total of 130 patients with C7-central sacral vertical line (CSVL) >0 mm and aged 10-18 years were recruited in this study from September 2013 to December 2014.

OUTCOME MEASURES

Data were analyzed to determine the optimal cutoff value of the ALAT measurement.

METHODS

The C7-CSVL and ALAT measurements were conducted respectively twice on plain film within a 2-week interval by two radiologists. The optimal cutoff value of the ALAT was analyzed via receiver operating characteristic (ROC) curve. Comparison variables were performed with chi-square test between the C7-CSVL and ALAT measurements for evaluating trunk imbalance. Kappa agreement coefficient method was used to test the intra-observer and interobserver agreement of C7-CSVL and ALAT.

RESULTS

The ROC curve area for the ALAT was 0.82 (95% confidence interval: 0.753-0.894, p<.001). The maximum Youden index was 0.51, and the corresponding cutoff point was 2.59°. No statistical difference was found between the C7-CSVL and ALAT measurements for evaluating trunk imbalance (p>.05). Intra-observer agreement values for the C7-CSVL measurements by observers 1 and 2 were 0.79 and 0.91 (p<.001), respectively, whereas intra-observer agreement values for the ALAT measurements were both 0.89 by observers 1 and 2 (p<.001). The interobserver agreement values for the first and second measurements with the C7-CSVL were 0.78 and 0.85 (p<.001), respectively, whereas the interobserver agreement values for the first and second measurements with the ALAT were 0.91 and 0.88 (p<.001), respectively.

CONCLUSIONS

The newly developed ALAT provided an acceptable optimal cutoff value for evaluating trunk imbalance in the coronal plane with a high level of intra-observer and interobserver agreement, which suggests that the ALAT is suitable for clinical use.

Cortical bone trajectory screws placement via pedicle or pedicle rib unit in the pediatric thoracic spine (T9-T12): A 2-dimensional multiplanar reconstruction study using computed tomography

Thoracic cortical bone trajectory (CBT) screw fixation can maximize the thread contact with cortical bone, and it is 53.8% higher than that of the traditional pedicle screws. Moreover, it can also enable less tissue dissection and retraction for reduced muscle disruption.Eighty pediatric patients are divided into 4 age groups and their thoracic vertebrae are analyzed on computed tomography (CT) images. The maximal screw length, maximal screw diameter, screw diameter, and the cephalad angle are measured. The statistical analysis is performed using the Student's t-test and Pearson's correlation analysis.Maximal screw length increases from T9 to T12 and there are significant differences between girls and boys at T9, T10, T11, and T12 in majority of groups (P < 0.05). The maximal screw diameter and screw diameter increase from T9 to T12. The maximal screw diameter ranges from 6.27 mm to 10.20 mm, whereas the screw diameter ranges from 3.87 mm to 6.75 mm. Meanwhile, the maximum cephalad angle is 23.06° and the minimum is 13.11°. No statistically significant differences in the cephalad angle are found at all levels.Our study establishes the feasibility of 4.5 to 5.5 mm CBT screws fixation via pedicle or pedicle rib unit in the pediatric thoracic spine. The entry point of the pediatric thoracic CBT screws is 6 o'clock orientation of the pedicle. Findings of our study also provide insights into the screw insertion angle and screw size decision.

Long-term effects of the Chêneau brace on coronal and sagittal alignment in adolescent idiopathic scoliosis

OBJECT

The aim of the present study was to retrospectively evaluate progressive correction of coronal and sagittal alignment and pelvic parameters in patients treated with a Chêneau brace.

METHODS

Thirty-two patients with adolescent idiopathic scoliosis (AIS) were assessed before initiation of bracing treatment and at the final follow-up. Each patient underwent radiological examinations, and coronal, sagittal, and pelvic parameters were measured.

RESULTS

No statistically significant modification of the Cobb angle was noted. The pelvic incidence remained unchanged in 59% of the cases and increased in 28% of the cases. The sacral slope decreased in 34% of the cases but remained unchanged in 50%. Thoracic kyphosis and lumbar lordosis were significantly decreased, whereas the sagittal vertical axis was significantly increased from a mean of -44.0 to -30.2 mm (p = 0.02). The mean pelvic tilt increased significantly from 4.5° to 8.3° (p = 0.002).

CONCLUSIONS

The Chêneau brace can be useful for preventing curvature progression in patients with AIS. However, the results of this study reveal high variability in the effect of brace treatment on sagittal and pelvic alignment. Treatment with the Chêneau brace may also influence sagittal global balance.

Computed tomography morphometric analysis for C-1 posterior arch crossing screw placement in the pediatric cervical spine

OBJECT

The goal of this study was to evaluate the feasibility of the C-1 posterior arch crossing screw fixation technique in the pediatric age group.

METHODS

One hundred twenty-three pediatric patients were divided into 6 age groups. Computed tomography morphometric analysis of the C-1 posterior arch was performed. Measurements included height, width, and length. Statistical analysis was performed using the Student t-test and linear regression analysis.

RESULTS

The mean measurement of the posterior arch was height (6.35 ± 1.80 mm), width (Width 1: 4.48 ± 1.25 mm; Width 2: 4.42 ± 0.68 mm; Width 3: 4.42 ± 0.50 mm), and length (14.48 ± 1.67 mm). Seven (6.93%) of the 101 children in Groups 1-4 and 13 (59.1%) of the 22 children in Groups 5 and 6 could safely accommodate placement of C-1 posterior arch crossing screws.

CONCLUSIONS

This investigation found that a C-1 posterior arch crossing screw was feasible in this group of Chinese pediatric patients, particularly in those 13 years and older. Preoperative thin-cut CT is essential for identifying children in whom this technique is applicable and for planning screw placement.

Percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion: a radiological and cadaveric study

PURPOSE

To design and investigate a novel technique of percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion.

METHODS

CT scans of 45 patients were collected and imported into Mimics software for three-dimensional (3D) reconstruction. Cylinders were drawn to simulate the trajectory of the oblique screw. Six measurements were obtained for each unit to design a right size cage: a the distance between the intersection of the simulated trajectory of the screw with the inferior border of the upper vertebra and its anteroinferior corner; b the distance between the intersection of the simulated trajectory of the screw with the superior border of the inferior vertebra and its anterosuperior corner; h the height of the intervertebral space; θ the angle between simulated trajectory of screw and the upper endplate of inferior vertebra; uw: the width of the inferior endplate of upper vertebra; iw: the width of upper endplate of inferior vertebra. Three intact adult fresh-frozen cadaveric specimens were obtained, percutaneous posterior transdiscal oblique screw fixation was performed under X-ray apparatus, and interbody cage was implanted by assistance with special self-retaining retractor system and endoscope.

RESULTS

According to the results of data measured from 3D images, trapezoid shape interbody cages with suitable size were designed. Percutaneous posterior oblique screw fixation with lateral interbody fusion was performed on three cadaveric specimens successfully.

CONCLUSION

Using specially designed trapezoid shape interbody cages, assisted by intra-operative image intensification and endoscope, it is feasible to perform percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion technique.

Pediatric femoral shaft fractures treated with titanium elastic nailing

The objective of this study was to prospectively compare intraoperative fluoroscopy time and clinical and radiological results in pediatric femoral shaft fractures treated with titanium elastic nailing (TEN) using a small-incision, blind-hand reduction vs closed reduction. From February 2008 to December 2009, sixty-eight children were enrolled in the study. Patients were divided into 2 groups: group A comprised 34 patients treated with a small-incision, blind-hand reduction technique and group B comprised 34 patients treated with a closed reduction technique. Operative time, intraoperative fluoroscopy time, fracture union time, and complications were recorded in both groups. Clinical and radiological results were assessed using the TEN scoring system. Mean operative time was 30.5±8.5 in group A and 53.0±15.0 minutes in group B, and mean fluoroscopy time was 28.4±18.5 seconds in group A and 65.0±28.5 seconds in group B. Operative time and fluoroscopy time were significantly longer in group B (P<.001). According to the TEN scoring system, the results were excellent in 31 patients and good in 3 patients in group A and excellent in 29 patients and good in 5 patients in group B. There was no significant difference between the 2 groups in terms of clinical and radiological results. There was also no significant difference in terms of fracture healing time, weight-bearing time, and complications. The small-incision, blind-hand reduction technique provided similar clinical results as closed reduction. This technique could be an alternative to closed reduction because it significantly reduced intraoperative radiation exposure and operative time.

The relationship between vitamin A and risk of fracture: meta-analysis of prospective studies

Osteoporotic fracture is a significant cause of morbidity and mortality and is a challenging global health problem. Previous reports of the relation between vitamin A intake or blood retinol and risk of fracture were inconsistent. We searched Medline and Embase to assess the effects of vitamin A (or retinol or beta-carotene but not vitamin A metabolites) on risk of hip and total fracture. Only prospective studies were included. We pooled data with a random effects meta-analysis with adjusted relative risk (adj.RR) and 95% confidence interval (CI). We used Q statistic and I(2) statistic to assess heterogeneity and Egger's test to assess publication bias. Eight vitamin A (or retinol or beta-carotene) intake studies (283,930 participants) and four blood retinol level prospective studies (8725 participants) were included. High intake of vitamin A and retinol were shown to increase risk of hip fracture (adj.RR [95% CI] = 1.29 [1.07, 1.57] and 1.40 [1.03, 1.91], respectively), whereas beta-carotene intake was not found to increase the risk of hip fracture (adj.RR [95% CI] = 0.82 [0.59, 1.14]). Both high or low level of blood retinol was shown to increase the risk of hip fracture (adj.RR [95% CI] = 1.87 [1.31, 2.65] and 1.56 [1.09, 2.22], respectively). The risk of total fracture does not differ significantly by level of vitamin A (or retinol) intake or by blood retinol level. Dose-response meta-analysis shows a U-shaped relationship between serum retinol level and hip fracture risk. Our meta-analysis suggests that blood retinol level is a double-edged sword for risk of hip fracture. To avoid the risk of hip fracture caused by too low or too high a level of retinol concentration, we suggest that intake of beta-carotene (a provitamin A), which should be converted to retinol in blood, may be better than intake of retinol from meat, which is directly absorbed into blood after intake.

Pooled analysis of non-union, re-operation, infection, and approach related complications after anterior odontoid screw fixation

Background

Anterior odontoid screw fixation (AOSF) has been one of the most popular treatments for odontoid fractures. However, the true efficacy of AOSF remains unclear. In this study, we aimed to provide the pooled rates of non-union, reoperation, infection, and approach related complications after AOSF for odontoid fractures.

Methods

We searched studies that discussed complications after AOSF for type II or type III odontoid fractures. A proportion meta-analysis was done and potential sources of heterogeneity were explored by meta-regression analysis.

Results

Of 972 references initially identified, 63 were eligible for inclusion. 54 studies provided data regarding non-union. The pooled non-union rate was 10% (95% CI: 7%–3%). 48 citations provided re-operation information with a pooled proportion of 5% (95% CI: 3%–7%). Infection was described in 20 studies with an overall rate of 0.2% (95% CI: 0%–1.2%). The main approach related complication is postoperative dysphagia with a pooled rate of 10% (95% CI: 4%–17%). Proportions for the other approach related complications such as postoperative hoarseness (1.2%, 95% CI: 0%–3.7%), esophageal/retropharyngeal injury (0%, 95% CI: 0%–1.1%), wound hematomas (0.2%, 95% CI: 0%–1.8%), and spinal cord injury (0%, 95% CI: 0%–0.2%) were very low. Significant heterogeneities were detected when we combined the rates of non-union, re-operation, and dysphagia. Multivariate meta-regression analysis showed that old age was significantly predictive of non-union. Subgroup comparisons showed significant higher non-union rates in age ≥70 than that in age ≤40 and in age 40 to <50. Meta-regression analysis did not reveal any examined variables influencing the re-operation rate. Meta-regression analysis showed age had a significant effect on the dysphagia rate.

Conclusions/Significances

This study summarized the rates of non-union, reoperation, infection, and approach related complications after AOSF for odontoid factures. Elderly patients were more likely to experience non-union and dysphagia.

Incidence of heterotopic ossification after implantation of interspinous process devices

OBJECT

This study aimed to investigate the incidence rate of heterotopic ossification (HO) after implantation of Coflex interspinous devices. Possible risk factors associated with HO were evaluated.

METHODS

The authors retrospectively analyzed patients who had undergone single-level (L4-5) implantation of a Coflex device for the treatment of lumbar spinal stenosis. Patient data recorded were age, sex, height, weight, body mass index, smoking habits, and surgical time. Heterotopic ossification was identified through lumbar anteroposterior and lateral view radiographs. The authors developed a simple classification for defining HO and compared HO-positive and HO-negative cases to identify possible risk factors.

RESULTS

Among 32 patients with follow-up times of 24-57 months, HO was detectable in 26 (81.2%). Among these 26 patients, HO was in the lateral space of the spinous process but not in the interspinous space in 8, HO was in the interspinous space but did not bridge the adjacent spinous process in 16, and interspinous fusion occurred at the level of the device in 2. Occurrence of HO was not associated with patient age, sex, height, weight, body mass index, smoking habits, or surgical time.

CONCLUSIONS

A high incidence of HO has been detected after implantation of Coflex devices. Clinicians should be aware of this possible outcome, and more studies should be conducted to clarify the clinical effects of HO.

Complications in degenerative lumbar disease treated with a dynamic interspinous spacer (Coflex)

PURPOSE

The purpose of this study was to quantify the intra- and postoperative complications of an interspinous process device (Coflex) in managing degenerative lumbar diseases and to investigate corresponding therapeutic strategies.

METHODS

Between January 2008 and December 2012, we retrospectively analysed a total of 131 patients who underwent decompressive surgery along with the Coflex system for the treatment of degenerative lumbar diseases. The related complications were reported, and appropriate measures were taken. Clinical outcomes and radiological data were collected and analysed, and clinical outcomes were evaluated with paired-samples T test.

RESULTS

Related complications occurred in 11 patients. Among them, six cases were found with surgical technique-related complications, including device-related complications in three cases: spinal process fracture (n = 1), Coflex loosening (n = 1), fixed-wing breakage (n = 1), dura mater tear in two cases and superficial wound infection in one case. All of them received corresponding conservative treatment and obtained a good result. The other five cases had non-device-related complications and required additional spinal surgery. The conservative therapy group had apparent improvement of VAS score and ODI, and remained well to final follow-up (P < 0.05). The second operation group also improved postoperatively (each P < 0.05).

CONCLUSION

The Coflex dynamic interspinous process device shows a low complication and re-operation rate. Standard operation and strict follow-up observation can effectively avoid surgical technique-related complications. The key points to ensure surgical effect and to reduce non-device-related complications are mastering surgical indications and thorough intra-operative decompression.

Fusion versus nonfusion for surgically treated thoracolumbar burst fractures: a meta-analysis

Background

Posterior pedicle screw fixation has become a popular method for treating thoracolumbar burst fractures. However, it remains unclear whether additional fusion could improve clinical and radiological outcomes. This meta-analysis was performed to evaluate the effectiveness of fusion as a supplement to pedicle screw fixation for thoracolumbar burst fractures.

Methodology/Principal Findings

MEDLINE, OVID, Springer, and Google Scholar were searched for relevant randomized and quasi-randomized controlled trials that compared the clinical and radiological efficacy of fusion versus nonfusion for thoracolumbar burst fractures managed by posterior pedicle screw fixation. Risk of bias in included studies was assessed using the Cochrane Risk of Bias tool. We generated pooled risk ratios or weighted mean differences across studies. Based on predefined inclusion criteria, 4 eligible trials with a total of 220 patients were included in this meta-analysis. The mean age of the patients was 35.1 years. 96.8% of the fractures were located at T12 to L1 level. Baseline characteristics were similar between the fusion and nonfusion groups. No significant difference was identified between the two groups regarding radiological outcome, functional outcome, neurologic improvement, and implant failure rate. The pooled data showed that the nonfusion group was associated with significantly reduced operative time (p<0.0001) and blood loss (p  = 0.0003).

Conclusions/Significances

The results of this meta-analysis suggested that fusion was not necessary when thoracolumbar burst fracture was treated by posterior pedicle screw fixation. More randomized controlled trials with high quality are still needed in the future.

Fusion after interspinous device placement

Lumbar interspinous devices are intended to unload the facet joints, restore foraminal height, lower intradisk pressure, and provide motion-preserving stabilization. They are an alternative treatment for patients with spinal degeneration and have increased in popularity in recent years. To the authors' knowledge, heterotopic ossification has not been previously reported around an interspinous device, and this is the first reported case of interspinous fusion after interspinous device placement.A 66-year-old man presented with a 3-year history of low back pain and a 4-month history of radiating pain down his left leg. A diagnosis was made of lumbar spinal stenosis and left disk herniation at L4-L5 after physical and imaging examinations. A dynamic interspinous device was implanted after the decompressive surgery. The patient's symptoms were relieved postoperatively. Thirty-two months later, he returned with back pain after being in a traffic accident. Lumbar radiographs showed a massive bony formation around the implant. Radiographs and a computed tomography scan 4.5 years later revealed that the implanted device segments were fused. No implant motion was seen on dynamic radiographs. Because the patient was symptom free, no interventions were performed.Heterotopic bone formation around a dynamic interspinous device may hamper motion preservation, and heterotopic ossification is a potential mid- and long-term complication.

Pedicle screw insertion accuracy with different assisted methods: a systematic review and meta-analysis of comparative studies

Studies revealed that navigation systems that provided intraoperative assistance might improve pedicle screw insertion accuracy, and also implied that different systems provided different pedicle screw insertion accuracy. A systematic review and meta-analysis was conducted to focus on the pedicle screw insertion accuracy with or without the assistance of image-guided system, and the variance among the different navigation systems. Comparative studies were searched on pedicle screw insertion accuracy between conventional and navigated method, and among different navigation systems. A total of 43 papers, including 28 clinical, 14 cadaveric and 1 model studies, were included in the current study. For clinical articles, there were 3 randomized clinical trials, 4 prospective comparative studies and 21 retrospective comparative studies. The incidence of pedicle violation among computer tomography-based navigation method group was statistically significantly less than that observed among the conventional group (OR 95% CI, in vivo: 0.32-0.60; in vitro: 0.24-0.75 P < 0.01). Two-dimensional fluoroscopy-based navigation system (OR 95% CI, in vivo: 0.27-0.48; in vitro: 0.43-0.88 P < 0.01) and three-dimension fluoroscopy-based navigation system (OR 95% CI, in vivo: 0.09-0.38; in vitro: 0.09-0.36 P < 0.01) also obtained significant reduced screw deviation rate over traditional methods. Between navigated approaches, statistically insignificant individual and pooled RR values were observed for all in vivo subgroups. Pooled estimate of in vitro studies show that computer tomography-based and three-dimension fluoroscopy-based navigation system provided more accurate pedicle screw insertion over two-dimension fluoroscopy-based navigation system. Our review showed that navigation provided a higher accuracy in the placement of pedicle screws compared with conventional methods. The superiority of navigation systems was obvious when they were applied to abnormal spinal structure. Although no strong in vivo evidence has detected significantly different pedicle screw placement accuracy among the three major navigation systems, meta-analysis revealed the variance in pedicle screw insertion accuracy with different navigation methods.