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Yutong Gu, Feng Zhang, Xiaoxing Jiang, Lianshun Jia and Robert McGuire

Object

The purpose of this study was to evaluate the feasibility and safety of minimally invasive pedicle screw fixation combined with percutaneous vertebroplasty (PVP) for treating acute thoracolumbar osteoporotic vertebral compression fracture (VCF) and preventing secondary VCF after PVP.

Methods

Twenty patients with a mean age of 73.6 years (range 65–85 years) who sustained fresh thoracic or lumbar osteoporotic VCFs without neurological deficits underwent minimally invasive pedicle screw fixation combined with PVP. Visual analog scale pain scores were recorded, and the Cobb angles and the central and anterior vertebral body (VB) heights were measured on the lateral radiographs before surgery and immediately, 1 month, 2 months, 3 months, 6 months, 1 year, and 2 years after surgery.

Results

The patients were followed up for an average of 26 months (range 24–30 months) after sugery. The visual analog scale score was found to be significantly decreased; from 7.3 ± 1.3 before surgery to 1.2 ± 0.7 immediately after surgery and to 0.7 ± 0.7 (p < 0.001) at the end of follow-up. The Cobb angle was 17.0° ± 4.3° before surgery and 6.4° ± 3.6° immediately after surgery. The central VB height that was 44.5% ± 7.6% before surgery increased to 74.6% ± 6.4% of the estimated intact central height immediately after surgery (p < 0.001). The anterior VB height increased from 50.7% ± 7.4% before surgery to 82.5% ± 6.7% of the estimated intact anterior height immediately after surgery (p < 0.001). There were no significant changes in the results obtained over the follow-up time period. There was no occurrence of new fracture in surgically treated or adjacent vertebrae in these patients.

Conclusions

Minimally invasive pedicle screw fixation combined with PVP is a good choice for the treatment of acute thoracolumbar osteoporotic VCF and can prevent the occurrence of new VCFs after PVP.

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Yahui Bai, Xinglong Zhi, Fengzeng Jian, Hongqi Zhang and Feng Ling

Perimedullary arteriovenous fistula (AVF) is a relatively rare spinal vascular malformation. Although it has traditionally been considered to be a congenital lesion, some cases identified in adults have suggested that the lesion may be acquired. The etiology and exact mechanism of these lesions are unknown. The authors present a case of a perimedullary AVF caused by a direct stabbing injury of the spinal cord and induced by subsequent kyphosis, and they discuss the pathogenesis and treatment strategy.

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Zihao Chen, Bin Liu, Jianwen Dong, Feng Feng, Ruiqiang Chen, Peigen Xie, Liangming Zhang and Limin Rong

OBJECTIVE

The purpose of this study was to compare the effectiveness and safety of anterior corpectomy and fusion (ACF) with laminoplasty for the treatment of patients diagnosed with cervical ossification of the posterior longitudinal ligament (OPLL).

METHODS

The authors searched electronic databases for relevant studies that compared the use of ACF with laminoplasty for the treatment of patients with OPLL. Data extraction and quality assessment were conducted, and statistical software was used for data analysis. The random effects model was used if there was heterogeneity between studies; otherwise, the fixed effects model was used.

RESULTS

A total of 10 nonrandomized controlled studies involving 819 patients were included. Postoperative Japanese Orthopaedic Association (JOA) score (p = 0.02, 95% CI 0.30–2.81) was better in the ACF group than in the laminoplasty group. The recovery rate was superior in the ACF group for patients with an occupying ratio of OPLL of ≥ 60% (p < 0.00001, 95% CI 21.27–34.44) and for patients with kyphotic alignment (p < 0.00001, 95% CI 16.49–27.17). Data analysis also showed that the ACF group was associated with a higher incidence of complications (p = 0.02, 95% CI 1.08–2.59) and reoperations (p = 0.002, 95% CI 1.83–14.79), longer operation time (p = 0.01, 95% CI 17.72 –160.75), and more blood loss (p = 0.0004, 95% CI 42.22–148.45).

CONCLUSIONS

For patients with an occupying ratio ≥ 60% or with kyphotic cervical alignment, ACF appears to be the preferable treatment method. Nevertheless, laminoplasty seems to be effective and safe enough for patients with an occupying ratio < 60% or with adequate cervical lordosis. However, it must be emphasized that a surgical strategy should be made based on the individual patient. Further randomized controlled trials comparing the use of ACF with laminoplasty for the treatment of OPLL should be performed to make a more convincing conclusion.

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Ganjun Feng, Xianfeng Zhao, Hao Liu, Huina Zhang, Xiangjun Chen, Rui Shi, Xi Liu, Xiaodan Zhao, Wenli Zhang and Beiyu Wang

Object

The aim of this study was to compare transplanted mesenchymal stem cells (MSCs) with nucleus pulposus cells (NPCs) in a degenerative disc model in rabbits to determine the better candidate for disc cell therapy.

Methods

Mesenchymal stem cells and NPCs were transplanted in a rabbit model of disc degeneration. Changes in disc height, according to plain radiography, T2-weighted signal intensity on MR imaging, histology, sulfated glycosaminoglycan (sGAG)/DNA, and associated gene expression levels, were evaluated among healthy controls without surgery, sham-operated animals in which only disc degeneration was induced, MSC-transplanted animals, and NPC-transplanted animals for a 16-week period.

Results

Sixteen weeks after cell transplantation, in the MSC- and NPC-transplanted groups, the decline in the disc height index was reduced and T2-weighted signal intensity increased compared with the sham-operated group. Safranin O staining showed a high GAG content, which was also supported by sGAG/DNA assessment. Disc regeneration was also confirmed at the gene expression level using real-time polymerase chain reaction. However, no significant differences in expression were found between the NPC- and MSC-transplanted groups.

Conclusions

Study data showed that MSC transplantation is effective for the treatment of disc degeneration and seems to be an ideal substitute for NPCs.

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Lin-Feng Wang, Ying-Ze Zhang, Yong Shen, Yan-Ling Su, Jia-Xin Xu, Wen-Yuan Ding and Ying-Hua Zhang

Object

The aim of this study was to investigate the clinical significance of both the signal intensity ratio obtained from MR imaging and clinical manifestations on the prognosis of patients with cervical ossification of the posterior longitudinal ligament.

Methods

The authors retrospectively reviewed the records of 58 patients with cervical ossification of the posterior longitudinal ligament who underwent cervical laminoplasty from February 1999 to July 2007. Magnetic resonance imaging (1.5-T) was performed in all patients before surgery. Sagittal T2-weighted images of the cervical spinal cord compressed by the ossified posterior longitudinal ligament showed increased intramedullary signal intensity, whereas the sagittal images obtained at the C7–T1 disc levels were of normal intensity. The signal intensity ratio between regions of intramedullary increased signal intensity and the normal C7–T1 disc level was calculated based on the signal intensity values generated from the MR imaging workstation. Patients were divided into 3 groups according to their signal intensity ratio (high, intermediate, and low signal intensity groups).

Results

There were significant differences between the 3 groups regarding recovery rate (p < 0.001), age (p = 0.022), duration of disease (p = 0.001), Babinski sign (p < 0.001), ankle clonus (p < 0.001), and both pre- and postoperative Japanese Orthopaedic Association score (p < 0.001). There was no significant difference in sex among the 3 groups (p = 0.391).

Conclusions

Patients with low signal intensity ratios that changed on T2-weighted imaging experienced a good surgical outcome. Low increased signal intensity might reflect mild neuropathological alteration in the spinal cord and greater recuperative potential. An increased signal intensity ratio with positive pyramidal signs indicates less recuperative potential of the spinal cord and a poor surgical outcome.

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Zhe-Feng Zhao, Li-Zhuang Yang, Chuan-Lu Jiang, Yong-Ri Zheng and Jin-Wei Zhang

Object

The authors' goal was to observe histopathological changes in the trigeminal nerve after Gamma Knife surgery (GKS) in rhesus monkeys, and to investigate the radiobiological mechanism of GKS for primary trigeminal neuralgia. The nerve length–dosage effect of irradiation is also discussed.

Methods

One of 5 rhesus monkeys randomly served as a control, and the other 4 monkeys were randomly administered a target radiation dose of 60, 70, 80, or 100 Gy (a different dose in each animal). The size of the collimator was 4 mm, and the target point was the trigeminal nerve root. In each experimental monkey, one side was exposed to single-target-point irradiation, and the contralateral side was exposed to double-target-point irradiation. After 6 months, the trigeminal nerve root was examined using light microscopy, transmission electron microscopy, and immunohistochemistry.

Results

At each radiation dose, the damage to the nerve tissue by single-target-point irradiation was identical to that caused by double-target-point irradiation. In the trigeminal nerve tissues of the monkeys irradiated with 60 and 70 Gy, there was limited nerve demyelination and degeneration, fragmentation, or loss of axons. In the trigeminal nerve tissue of the monkey irradiated with 80 Gy, the nerve tissue showed a disordered structure. In the trigeminal nerve tissue of the monkey irradiated with 100 Gy, there was severe derangement in the structure of the nerve tissue, and extensive demyelination, fragmentation, and loss of axons.

Conclusions

The target doses of 60 and 70 Gy have very little impact on the structure of the trigeminal nerve. Irradiation at 80 Gy can cause partial degeneration and loss of axons and demyelination. A 100-Gy dose can cause some necrosis of neurons. Comparing the single-target-point with the double-target-point irradiation, the extent of damage to the nerve tissue is identical, and no difference in the nerve length–dosage effect was found.

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Hong-Qi Zhang, Ling-Qiang Chen, Shao-Hua Liu, Di Zhao and Chao-Feng Guo

Object

The object of this study was to evaluate the efficacy and safety of posterior decompression with kyphosis correction for thoracic myelopathy due to ossification of the ligamentum flavum (OLF) and ossification of the posterior longitudinal ligament (OPLL) at the same level.

Methods

Between January 2003 and December 2005, 11 patients (8 men and 3 women) with thoracic myelopathy due to OLF and OPLL at the same level underwent posterior decompressive laminectomy and excision of OLF. Posterior instrumentation was also performed for stabilization of the spine and reducing the thoracic kyphosis angle by approximately 5–15° (kyphosis correction), and spinal fusion was performed in all cases. The follow-up period ranged from 2 to 4 years (mean 2.8 years). The outcomes were evaluated using a recovery scale based on the Japanese Orthopaedic Association classification. The score of each patient was calculated before surgery, 1 year after surgery, and at the final follow-up visit.

Results

After surgery, the thoracic kyphosis in the stabilization area was reduced from 30.0 ± 4.02° to 20.8 ± 2.14° on average. The mean score on the Japanese Orthopaedic Association scale improved from 3.5 ± 1.69 preoperatively to 8.5 ± 1.63 at the final follow-up, with a recovery rate of 68.0%. The results were good in 9 patients and fair in 2 patients. Postoperative MR imaging showed that the spinal cord was shifted posteriorly and decompressed completely in all cases. Myelopathy was not aggravated in any case after surgery.

Conclusions

A considerable degree of neurological recovery was observed after posterior decompression and kyphosis correction. The procedure is easy to perform with a low risk of postoperative paralysis. The authors therefore suggest that the procedure is useful for patients whose spinal cords are severely impinged by OLF and OPLL at the same level.

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Zhong Yang, Yuan Xue, Qin Dai, Chao Zhang, H. Fang Zhou, J. Feng Pan and Dan Sheng

Object

The authors introduce a novel technique to treat thoracic myelopathy caused by ossification of the ligamentum flavum (OLF): upper facet joint en bloc resection. This surgical procedure avoids surgery to the most heavily compressed cord surface, contact with the cord, and cord injury. The epidural venous plexus bleeding point can be directly seen and easily controlled during the decompression.

Methods

Between January 2007 and January 2009, thoracic myelopathy caused by OLF was diagnosed in 38 patients using plain radiography, CT, and MRI, and diagnoses were confirmed by postoperative pathological examination. All upper facet joint en bloc resection procedures were performed in 2 steps. First, the bony structures above the upper facet joint surfaces were resected and the upper facet joints were isolated. Second, en bloc resection of the upper facet joint was performed by dissection of the junction between the pedicle and upper facet joint. Intraoperative neurological monitoring was performed in all cases. The modified Japanese Orthopaedic Association (mJOA) scoring system was used to assess neurological status. The degree of postoperative expansion of the spinal cord was calculated on axial MR images. The pre- and postdecompression Cobb angle was applied to assess the magnitude of local kyphosis.

Results

Of the 38 cases of OLF, 6 were single level, 12 were double level, and 20 were multilevel. Of the 92 ossified segments in this study, 23 (25.0%) were located in the upper thoracic spine (T1–4), 13 (14.1%) were located in the midthoracic spine (T5–8), and 56 (60.9%) were located in the lower thoracic spine (T9–L1). The mean intraoperative blood loss was 340 ± 54 ml. The neurological status improved during follow-up (mean 46.1 months) from a preoperative mean mJOA score of 5.39 ± 1.52 to 8.97 ± 1.22 points (t = 18.39, p < 0.05). The neurological function recovery rate ranged from 28.6% to 100%. The mean increase in pre- and postoperative kyphosis of the involved vertebrae was only 1.3° ± 1.6°. The increase in the cross-sectional area of the dural sac at the level of maximum compression suggested that decompression was complete.

Conclusions

Upper facet joint en bloc resection is effective and may be a reasonable alternative treatment choice for thoracic myelopathy caused by OLF.

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Shuyu Hao, Christopher S. Hong, Jie Feng, Chunzhang Yang, Prashant Chittiboina, Junting Zhang and Zhengping Zhuang

Maffucci syndrome is a rare disease characterized by multiple enchondromas and soft-tissue hemangiomas. Additionally, neuroendocrine tumors including pituitary adenomas have been described in these patients. The underlying genetic etiology lies in somatic mosaicism of mutations in isocitrate dehydrogenase 1 (IDH1) or isocitrate dehydrogenase 2 (IDH2). This report describes a patient with Maffucci syndrome who presented with intracranial tumors of the skull base and suprasellar region. The patient underwent resection of both intracranial tumors, revealing histopathological diagnoses of chondrosarcoma and pituitary adenoma. DNA sequencing of the tumors was performed to identify common IDH1/2 mutations. Clinical, radiological, and biochemical assessments were performed. Genotypic studies used standard Sanger sequencing in conjunction with a target-specific peptide nucleic acid to detect IDH1 mutations in tumor tissues. DNA sequencing demonstrated identical IDH1 mutations (c.394C > T) in both tumors.

To the authors’ knowledge, this report provides the first genetic evidence for the inclusion of pituitary adenomas among tumors characterizing Maffucci syndrome. In patients who are newly diagnosed with Maffucci syndrome, it is appropriate to monitor for development of pituitary pathology and neuroendocrine dysfunction.