Anterior cervical plating combined with zero-profile anchored spacer for the treatment of cervical facet dislocation in elderly patients.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of anterior cervical plating combined with zero-profile (Z-P) anchored spacer for the treatment of cervical facet dislocation in elderly patients. METHODS: This is a retrospective study. Twelve elderly patients (from 57 to 77 years old, averaged 65 years) with unilateral or bilateral facet dislocation of sub-axial cervical spine from September 2015 to September 2019 surgically treated at the authors' hospital were enrolled in this study. The patients with osteoporosis or osteopenia were all surgically treated by anterior-only procedure using cervical plating combined with zero-profile anchored spacer after closed manual reduction under general anesthesia and spinal cord monitoring. The operation times (OT), estimated blood loss (EBL), perioperative complications, were recorded. The clinical evaluation included visual analogue scales (VAS) and the American Spinal Injury Association (ASIA) scale. The radiographic evaluation included kyphotic angle (KA) and disc height (DH) and the fusion rate. RESULTS: Anterior discectomy, interbody fusion and fixation were performed in all patients after the disloctions were reduced by manual maneuver. The average OT was 66 minutes, with a range from 45 to 110 minutes. The EBL averaged 42 ml per surgical procedure, with a range from 20 to 60 ml. The VAS, ASIA, KA were improved significantly after surgery (P<0.05). The average follow-up time was 24.2 months, with a range from 12 to 38 months. There were no statistical differences between the immediately post-op KA and KA at the last follow-up (P>0.05). No disc space subsidence was observed statistically (P<0.05) Interbody fusion was obtained in all patients. Two patient experienced slight difficulty in swallowing, which were improved 6 weeks later. There were no hardware failure, no segmental instability, no wound infection or other complications. CONCLUSIONS: Manual reduction with spinal cord monitoring under general anesthesia is a safe and efficient option and the anterior cervical plating combined with Z-P spacer could achieve reliable fixation for the patients with cervical facet dislocation in the elderly patients with osteoporosis or osteopenia.

Estrogen-Related Receptor α: A Significant Regulator and Promising Target in Bone Homeostasis and Bone Metastasis.

Bone homeostasis is maintained with the balance between bone formation and bone resorption, which is involved in the functional performance of osteoblast and osteoclast. Disruption of this equilibrium usually causes bone disorders including osteoporosis, osteoarthritis, and osteosclerosis. In addition, aberrant activity of bone also contributes to the bone metastasis that frequently occurs in the late stage of aggressive cancers. Orphan nuclear receptor estrogen-related receptor (ERRα) has been demonstrated to control the bone cell fate and the progression of tumor cells in bone through crosstalk with various molecules and signaling pathways. However, the defined function of this receptor in bone is inconsistent and controversial. Therefore, we summarized the latest research and conducted an overview to reveal the regulatory effect of ERRα on bone homeostasis and bone metastasis, this review may broaden the present understanding of the cellular and molecular model of ERRα and highlight its potential implication in clinical therapy.

Antibiotic-loaded calcium sulfate beads in spinal surgery for patients with spondylodiscitis: a clinical retrospective study.

BACKGROUND: Various surgical techniques for treating spondylodiscitis have been proposed, but the optimal surgical treatment remains controversial. In this study, we propose a new procedure that is implanting antibiotic-loaded calcium sulfate (CS) beads into the disc after debridement using the Quadrant channel combined with percutaneous fixation through a single-stage posterolateral approach for the treatment of spondylodiscitis. Thus, the purpose of this study is to assess the safety and efficacy of this procedure. METHODS: This study collected the data of 32 patients with spine spondylodiscitis and was surgically treated in our department from July 2015 to August 2020. The Demographic data included age, gender, involved segment, and complications were collected. The intra-operative details, results of culture, functional outcome, radiologic outcome, and length of hospital stay, laboratory examination were recorded. RESULTS: The mean age of the 32 patients was 61.1 ± 9.7 years old. The mean operative time was 135.0 ± 30.6 minutes, and the mean blood loss was 243.4 ± 92.1 ml. The positive rate of culture was 72%. The mean Visual analogue scale (VAS) and Oswestry Disability Index (ODI) score significantly improved from 7.5 to 1.6 and from 65% to 10%. Cobb angle was significantly improved and could be maintained at final follow-up. New bone formation was observed in all patients. There were no recurrences of infection in our study. CONCLUSIONS: The posterolateral debridement and percutaneous fixation combined with antibiotic-loaded calcium sulfate beads filling are effective in the treatment of spondylodiscitis in terms of infection control, early mobilization, and recovery.

Microscopic extra-laminar sequestrectomy (MELS) for the treatment of hidden zone lumbar disc herniation: report of the surgical technique, patient selection, and clinical outcomes.

BACKGROUND: The area which located at the medial pedicle, posterior vertebral body and ventral hemilamina is defined as the hidden zone. Surgical management of hidden zone lumbar disc herniation (HZLDH) is technically challenging due to its difficult surgical exposure. The conventional interlaminar approach harbors the potential risk of post-surgical instability, while other approaches consist of complicated procedures with a steep learning curve and prolonged operation time. OBJECTIVE: To introduce microscopic extra-laminar sequestrectomy (MELS) technique for treatment of hidden zone lumbar disc herniation and present clinical outcomes. METHODS: Between Jan 2016 to Jan 2018, twenty one patients (13 males) with HZLDH were enrolled in this study. All patients underwent MELS (19 patients underwent sequestrectomy only, 2 patients underwent an additional inferior discectomy). The nerve root and fragment were visually exposed using MELS. The operation duration, blood loss, intra- and postoperative complications, and recurrences were recorded. The Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and the modified MacNab criteria were used to evaluate clinical outcomes. Postoperative stability was evaluated both radiologically and clinically. RESULTS: The mean follow-up period was 20.95 ± 2.09 (18-24) months. The mean operation time was 32.43 ± 7.19 min and the mean blood loss was 25.52 ± 5.37 ml. All patients showed complete neurological symptom relief after surgery. The VAS and ODI score were significantly improved at the final follow-up compared to those before operation (7.88 ± 0.70 vs 0.10 ± 0.30, 59.24 ± 10.83 vs 11.29 ± 3.59, respectively, p < 0.05). Seventeen patients (81%) obtained an "excellent" outcome and the remaining four (19%) patients obtained a "good" outcome based the MacNab criteria. One patient suffered reherniation at the same level one year after the initial surgery and underwent a transforaminal endoscopic discectomy. No major complications and postoperative instability were observed. CONCLUSIONS: Our observation suggest that MELS is safe and effective in the management of HZLDH. Due to its relative simplicity, it comprises a flat surgical learning curve and shorter operation duration, and overall results in reduced disturbance to lumbar stability.

Minimally invasive far lateral debridement combined with posterior instrumentation for thoracic and lumbar tuberculosis without severe kyphosis.

BACKGROUND: Anti-tuberculous therapy (ATT) alone cannot easily cure spine tuberculosis (STB) though it is the most essential treatment. Many studies have confirmed the efficacy of the surgical treatment of STB through anterior, anterolateral, posterior debridement, and intervertebral fusion or combined with internal fixation. However, the conventional surgical approach requires extensive exposure of the affected areas with high rates of morbidity and mortality. Recently, minimally invasive surgery has come into use to reduce iatrogenic trauma and relevant complications. Here, we introduced a novel technique for the treatment of thoracic and lumbar spine tuberculosis: minimally invasive far lateral debridement and posterior instrumentation (MI-FLDPI). In this study, we evaluated the technical feasibility, the clinical outcomes, and the postoperative complications. METHODS: We did a prospective, non-randomized study on this new technique. Twenty three patients (13 males) with thoracic or lumbar spine tuberculosis who underwent minimally invasive far lateral debridement and posterior instrumentation were included in the study. The preoperative comorbidities, operation duration, intra-operative hemorrhage, Cobb's angles, and postoperative complications were recorded and analyzed. Clinical outcomes were evaluated by Visual Analog Scale (VAS), Oswestry Disability Index (ODI), neurological recovery, and eradication of tuberculosis. Radiological outcomes were evaluated by changes in Cobb's angle and fusion status of the affected segments. RESULTS: The patients were followed for an average of 19 months (ranging from 12 to 36 months). At the final follow-up, CRP and ESR of all patients were normal. The VAS and ODI were significantly improved compared with preoperative values (P < 0.05). No evident progression of the kyphotic deformity was found after surgery. Twenty two patients showed spontaneous peripheral interbody fusion 1 year after surgery. There were no failure of the instrumentation even though a young female with drug-resistant tuberculosis showed no sign of interbody fusion at the third year follow-up. All the patients with preoperative neurological deficit showed complete recovery at the final follow-up. CONCLUSIONS: MI-FLDPI using expandable tubular retractor could be recommended to treat thoracic and lumbar spine tuberculosis for the advantages of less trauma, earlier recovery, and less complications. Spontaneous peripheral interbody fusion was observed in nearly all the cases even without bone grafting.

Neuroprotective effect of methylprednisolone combined with placenta-derived mesenchymal stem cell in rabbit model of spinal cord injury.

The aim of this study was to assess the ability of the combination treatment of methylprednisolone (MP) and placenta-derived mesenchymal stem cells (PDMSCs) in a rabbit model of spinal cord injury (SCI). Rabbits were randomly divided into four groups: group 1 (control), group 2 (MP), group 3 (PDMSCs) and group 4 (MP + PDMSCs). In all groups, the spinal cord injury model was created by the weight drop method. Levels of malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were determined by kit. Histopathological examination was also performed. Neurological evaluation was carried out with the Tarlov scoring system. The results showed both MP and PDMSCs had neuroprotective effects, and combining the administration of MP with PDMSCs was shown a significant effect on the recovery of neurological function. Therefore, the combined use of MP and PDMSCs can be used as a potential therapeutic method for SCI.

Biomechanical analysis of the annular ligament in Monteggia fractures using finite element models.

BACKGROUND: The pathogenesis of Monteggia injuries remains controversial. The current study biomechanically explored the pathological changes during Monteggia fractures using finite element analysis. METHODS: Two cadaveric forearm specimens underwent computed tomography in both the prone and supine positions. The images were imported to Mimics to construct three-dimensional images. The obtained models of the annular ligaments were assembled onto the bones. Two thin gaps were produced at the proximal third of the ulna to simulate a Monteggia fracture. The models were analyzed mechanically. The initial fracture process was simulated by constraining the distal portions of the radius and ulna and the dorsal fracture sites of the ulna. The mechanical changes of the annular ligament in the two positions were observed and compared. RESULTS: In the prone position, the maximum Z-axial displacement of the annular ligament was close to that along the Y-axis, although with a significant difference (P < 0.01). In the supine position, the X-axial displacement dramatically increased (P < 0.01), while it was noticeably decreased along the Z-axis (P < 0.01). CONCLUSIONS: Biomechanical changes may partially explain the pathological changes in the annular ligament during Monteggia fractures; longitudinal displacement of the radial head causes it to slip out of the annular ligament while the ligament remains intact.

Ultra-bright near-infrared-emitting HgS/ZnS core/shell nanocrystals for in vitro and in vivo imaging.

Near-infrared (NIR)-emitting nanocrystals have enormous potential as an enabling technology for applications ranging from tunable infrared lasers to biological labels. Mercury chalcogenide NCs are one of the attractive NCs with NIR emission; however, the potential toxicity of Hg restricts their diverse applications. Herein, we synthesized low-toxic, highly luminescent and stable GSH-capped HgS/ZnS core/shell NCs by an aqueous route for the first time. The core/shell structure was characterized by using TEM, XRD and XPS, which provide evidence for the shell growth. After the successful growth of an appropriate ZnS shell around HgS NCs, poorly luminescent HgS NCs converted into ultra-bright HgS/ZnS NCs, substantially increasing photoluminescence quantum yield up to 43.8% at room temperature. The fluorescence peak of HgS/ZnS NCs was successfully tuned in a wide NIR window ranging from 785 nm to 1060 nm with high emission efficiency by controlling the synthetic pH values. Significantly, an in vitro cytotoxicity study clearly demonstrated that the HgS/ZnS NCs exhibited good biocompatibility as evidenced by the cell viability retained above 80% at a dose of HgS/ZnS NCs up to 150 µg mL-1. More importantly, the low-toxic NIR-emitting HgS/ZnS NCs have proved to be an effective fluorescent label in in vitro and in vivo imaging. The penetration depth reached 2 cm in a nude mouse with distinct separation of autofluorescence and NCs' fluorescence, giving excellent contrast at all depths. The novel highly-luminescent NIR-emitting HgS/ZnS NCs open up new possibilities for highly-sensitive, highly spectrally resolved and multicolor imaging in biomedical applications.

Effect of methotrexate on the mechanical properties and microstructure of calcium phosphate cement.

Calcium phosphate cement (CPC) is widely used as an antitumor bone-filling material. Methotrexate (MTX) is recognized as an effective chemotherapy medicine. The current study examined the effects of MTX on the mechanical properties and microstructure of CPC. Methotrexate-loaded CPC at mass ratios of 0%, 0.1%, 0.2%, and 0.5% were designated as groups A, B, C, and D, respectively, and were pressed into precast cylindrical molds. Solidification time, axial compressive strength, transverse compressive strength, and rotational tensile strength were measured, and scanning electron microscopy images were captured before and after MTX-CPC microstructure changes occurred. Average initial and final setting times increased gradually with increasing drug concentration, but this increase was not significant among the groups. Average axial transverse compressive strength and rotational tensile strength of groups B and C were not significantly different from those of group A (P>.05); however, there was a significant difference in these properties between groups A and D (P<.05). Scanning electron microscopy observations showed a porous crystalline structure. The addition of MTX to CPC does not significantly affect the basic crystal structure and setting time of CPC. Adding MTX at mass ratios of 0.1% and 0.2% to CPC does not lead to a significant difference in mechanical strength and can therefore be applied in clinical practice. This study may shed some light on the future application of MTX-loaded CPC in the treatment of bone defects after tumor excision.

Evaluation of occipitocervical neutral position using lateral radiographs.

BACKGROUND: Intraoperative assessment of neutral occipitocervical balance during a fusion procedure is challenging. We designed this study to introduce a more comprehensive method of evaluating the occipitocervical neutral position using lateral radiographs. METHODS: One hundred neutral lateral cervical spine radiographs interpreted as normal were studied. Cervical spine radiographs were performed using a standard technique. The occipitocervical angle, the occipitocervical distance, and the mandible cervical distance were measured by different observers. RESULTS: A difference analysis was performed between males and females. The mean mandible cervical distances were 11.0 and 11.2 mm in males and females, respectively. The mean occipitocervical distances were 22.0 mm (male) and 19.6 mm (female), and the occipitocervical angles were 47.2° (male) and 45.5° (female). The occipitocervical distance revealed significant differences between males and females (p <0.01). However, there were no significant differences between sexes for the occipitocervical angle or the mandible cervical distance (p >0.01). CONCLUSIONS: This study offers reference values for the occipitocervical angle and occipitocervical distance for the estimation of the occipitocervical neutral position. The introduction of the mandible cervical distance may make the evaluation more direct and more comprehensive during surgery because of its sensitivity to changes in head position.

Comparison of the risk of breakage of two kinds of sacroiliac screws in the treatment of bilateral sacral fractures.

PURPOSE: This study aimed at comparing the risk of breakage of lengthened sacroiliac screw and ordinary sacroiliac screw for the treatment of bilateral vertical sacral fractures to provide reference for clinical application. METHODS: A finite element model of type C pelvic ring injury (bilateral type Denis II fracture of sacrum) was produced. The bilateral sacral fractures were fixed with lengthened sacroiliac screw and ordinary sacroiliac screw in seven types of models, respectively. The maximal Von Mises stresses and stress distribution of the two kinds of screws in the case of standing on both feet were measured and compared. RESULTS: (1) Whether in lengthened sacroiliac screw or ordinary sacroiliac screw, the maximal Von Mises stress of screw fixation only in S1 segment is the largest, and the maximal Von Mises stress of screw fixation only in S2 segment is minor, and the maximal Von Mises stress of screw fixation in S1 and S2 segments, respectively, is the least. (2) When S1 and S2 were both fixed with ordinary screws, the maximal Von Mises stress of screw in S1 segment is larger than that of S2. When S1 and S2 were both fixed with lengthened screws, the maximal Von Mises stress of screw in S1 segment is similar to that of S2. (3) The maximal Von Mises stresses of bilateral symmetrical screws are similar. (4) When only S1 was fixed, the maximal Von Mises stress of lengthened screw is less than that of ordinary screw. When only S2 was fixed, the maximal Von Mises stress of lengthened screw is larger than that of ordinary screw. When S1 and S2 were both fixed, the maximal Von Mises stress of lengthened screw is slightly less than that of ordinary screw. (5) Whether in lengthened screw or ordinary screw, the stress concentrations all exhibited at the regions of screws corresponding to the sacral fracture regions and the part between sacral bilateral fracture lines. Compared with ordinary screw, the stress distribution in lengthened screw is more homogeneous. Whether in lengthened screw or ordinary screw, the stress distribution of only one sacral segment fixation is more concentrated than that of two sacral segments' fixation. When S1 and S2 were both fixed, the stress distribution of upper screw is more concentrated and that of lower screw is more homogeneous. CONCLUSION: In a finite elements simulated type C pelvic ring disruption (bilateral type Denis II sacral fracture), the breakage risk of screws fixed in double-segment bilaterally symmetrically is low, and the breakage risk of screws fixed in S2 segment is lower than that of S1 segment. The bilaterally symmetrical screw fixation in double-segment is strongly recommended to reduce the breakage risk of screws. In addition, the breakage risk of lengthened screws is lower than that of ordinary screws except when screws are fixed in only S2 segment, which merits attention.

Management of subaxial cervical facet dislocation through anterior approach monitored by spinal cord evoked potential.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To discuss the clinical efficacy of anterior cervical surgery of decompression, reduction, stabilization, and fusion in treating subaxial cervical facet dislocation without spinal cord injury or with mild spinal cord injury monitored by spinal cord evoked potential. SUMMARY OF BACKGROUND DATA: The optimal treatment of lower cervical facet dislocation has been controversial. Because of the risk of iatrogenic damage of neurological function, it is challenging for surgeons to manage the lower cervical facet dislocation without or with mild spinal cord injury. To avoid the risks, more secure strategy need to be designed. METHODS: A retrospective study was performed on 17 cases of subaxial cervical facet dislocation without spinal cord injury or with mild spinal cord injury treated by anterior cervical surgery under spinal cord evoked potential monitor from January 2008 to June 2012. There were 12 males, 5 females, with a mean age of 40.1 years (from 21 to 73 yr). Dislocation sites: 1 in C3-C4, 2 in C4-C5, 6 in C5-C6, 8 in C6-C7; 10 cases with unilateral cervical facet dislocation, 7 cases with bilateral dislocation. Thirteen patients were preoperatively classified as grade D and 4 as E according to Frankel standard. All patients were followed up for average of 16 months. RESULTS: All operations were completed successfully. Postoperative radiographs showed that the sequence and curvature of the cervical spine were well recovered. And, evidence of intervertebral fusion was observed at 3 months in all cases. No redislocation or symptoms of spinal cord injury occurred. Thirteen cases with mild spinal cord injury recovered at 1 month after operation. CONCLUSION: Anterior cervical surgery of decompression, reduction, stabilization, and fusion monitored by spinal cord evoked potential is an effective and safe method for treatment of subaxial cervical facet dislocation without or with mild spinal cord injury. LEVEL OF EVIDENCE: 4.

[Efficacies of percutaneous multiple needle puncturing for releasing hip adductor muscle during total hip arthroplasty].

OBJECTIVE: To summarize our experiences of applying percutaneous multiple needle puncturing technique for releasing adductor muscle during total hip arthroplasty (THA) for ischemic necrosis of femoral head and provide rationales for clinical practice. METHODS: From January 2008 to December 2012, 36 adult patients with ischemic necrosis of femoral head (36 hips) and 36 adult patients with femoral neck fracture (36 hips) were recruited. The group of ischemic necrosis of femoral head was designated as experiment group in which there were 29 males and 7 females with an average age of 67.9 (60-78) years. According to the Ficat system, there were type III (n = 24) and type IV (n = 12) . The affected leg shortening of this group prior to surgery was over 2 cm. The group of femoral neck fracture was selected as control group in which there were 16 males and 20 females with an average age of 70.1 (60-82) years. According to the Garden system, there were type III (n = 16) and type IV (n = 20). All cases underwent THA with Press-fit prosthesis. After fixing prosthetic components, leg length discrepancy was corrected. And percutaneous multiple needle puncturing was applied for releasing adductor muscle in experiment group. The follow-up period was 2 years. The safety and efficiency were evaluated by HHS (Harris Hip Score) and the range of motion (ROM) of hip extorsion and abduction. RESULTS: There was no occurrence of such early complications as palsy of obturator nerve, hematoma in adductor muscle area or serious deep vein embolism.No serious complications of deep infection, femoral head dislocation, recurrent adductor muscle contracture, prosthesis loosening, subsidence, excursion or penetration occurred up until the final follow-up. The range of hip motion of extorsion and abduction: (1) in experimental group, the postoperative ROM (abduction:44.9 ± 0.8, extorsion:45.1 ± 0.9) was significantly larger than that of preoperative (abduction: 30.0 ± 4.6, extorsion:31.5 ± 4.6) ; (2) the postoperative ROM of experimental group had no significant changes until the final follow-up (abduction: 44.7 ± 0.9, extorsion:45.25 ± 0.81); (3) at the last time of follow-up, no significant inter-group difference existed in ROM (abduction:44.86 ± 0.68, extorsion:45.6 ± 0.8). HHS: (1) in experimental group, HHS increased significantly from 39.64 ± 3.93 preoperatively to 82.8 ± 3.6 at 3 months postoperatively; (2) in two groups, HHS of 2 years postoperation (experimental group: 88.6 ± 4.1, control group: 89.1 ± 4.0) was significantly larger than that of 3 months postoperation (experimental group: 82.8 ± 3.6, control group:83.1 ± 3.1); (3) at the time of 3 months and 2 years postoperation, no significant inter-group difference existed in HHS. CONCLUSION: The technique percutaneous multiple needle puncturing for releasing adductor muscle during THA for ischemic necrosis of femoral head is both safe and efficacious. And it solves the problems of soft tissue balancing mini-invasiveness.

Bone cement enhanced pedicle screw fixation combined with vertebroplasty for elderly patients with malignant spinal tumors.

BACKGROUND: Older patients with malignant spinal tumors are difficult to treat because they have many co-morbidities including osteoporosis. The purpose of this research is to discuss the technique and clinical outcome of bone cement enhanced pedicle screw fixation combined with vertebroplasty (the Sandwich Procedure) for elderly patients with severe osteoporosis and malignant spinal tumors. METHODS: This study includes 28 consecutive elderly patients with malignant thoracic or lumbar spinal tumors. There were nine patients with myelomas, and 19 patients with metastatic bone tumors. The Sandwich Procedure began with curettage of the tumor and a vertebroplasty with bone cement (polymethyl methacrylate, PMMA), followed by PMMA enhanced pedicle screw fixation. Patients were evaluated with the visual analogue scale (VAS), oswestry disability index (ODI), American Spinal Cord Injury Association (ASIA) neurological function classification, and the radiographic degree of kyphosis (Cobb angle). Data were analyzed using paired t-test to compare the pre- and post-operative values. The complications, local recurrences, and the survival status were also recorded. RESULTS: There was no operative mortality, and the mean operative time was 210 minutes (range 150 - 250 minutes). The average blood loss was 1550 ml (range 650 - 3300 ml). The average amount of cement for vertebroplasty was 3.6 ml (range 3 -5 ml). The VAS, ODI, and ASIA scores were significantly improved after surgery (P < 0.05). However, we found no differences between the pre and post-operative Cobb angles. The shortest survival time was 3 months, and we found no evidence of local recurrence in this group of patients. CONCLUSION: The Sandwich Procedure is a safe operation and provides symptomatic relief in these difficult patients, permitting further treatment with chemotherapy or radiotherapy.

[Comparison of stability of sacroiliac screws in the treatment of bilateral sacral fractures in a finite element model].

OBJECTIVE: To compare the stability of sacroiliac screws fixation for the treatment of bilateral vertical sacral fractures to provide reference for clinic application. METHODS: A finite element model of Tile C pelvic ring injury (bilateral type Denis II fracture of sacrum) was produced. The bilateral sacral fractures were fixed with sacroiliac screws in 4 types of models respectively: two bidirectional sacroiliac screws fixation in the S1 segment, two bidirectional sacroiliac screws fixation in the S2 segment, one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment, two bidirectional sacroiliac screws fixation in S1 and S2 segments respectively. By the ABAQUS 6.9.1 software, in the case of standing on both feet, 600 N vertical load was imitated to be imposed to the superior surface of the sacrum and downward translation and backward angle displacement of the middle part of the sacral superior surface and everted angle displacement of the top of iliac bones were extracted for analysis. The stability of sacroiliac screws fixation was compared according to the principle of the better stability the smaller displacement. RESULTS: The stability of 2 bidirectional sacroiliac screws fixation in S1 and S2 segments respectively was markedly superior to that of 2 bidirectional sacroiliac screws fixation in S1 or S2 segment and was also markedly superior to that of one sacroiliac screw fixation in S1 segment and one sacroiliac screw fixation in S2 segment. The vertical and everted stability (the downward translation: 0.531 mm; the everted angle displacement: 0.156° (left side), 0.163° (right side)) of sacroiliac screws fixation in two bidirectional sacroiliac screws fixation in the S2 segment was superior to that of two bidirectional sacroiliac screws fixation in the S1 segment (the downward translation: 0.673 mm; the everted angle displacement: 0.200° (left side), 0.232° (right side)). The rotational stability of two bidirectional sacroiliac screws fixation in the S1 segment (the backward angle displacement: 0.269°) was superior to that of two bidirectional sacroiliac screws fixation in the S2 segment (the backward angle displacement: 0.287°). Moreover, the rotational stability of one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment was inferior to that of two bidirectional sacroiliac screws fixation in the S1 segment or two bidirectional sacroiliac screws fixation in the S2 segment, and the vertical and everted stability of one sacroiliac screw fixation in the S1 segment and one sacroiliac screw fixation in the S2 segment was between that of two bidirectional sacroiliac screws fixation in the S1 segment and two bidirectional sacroiliac screws fixation in the S2 segment. CONCLUSIONS: Two bidirectional sacroiliac screws fixation in S1 and S2 segments respectively is recommended to be utilized for fixing bilateral sacral fractures of Tile C pelvic ring injury as far as possible. It is suggested to choose sacral segments in which sacroiliac screws fixed according to vertical, rotational and everted stability degree of sacral fractures.

Comparison of stability of two kinds of sacro-iliac screws in the fixation of bilateral sacral fractures in a finite element model.

OBJECTIVE: To compare the stability of lengthened sacro-iliac screw and sacro-iliac screw for the treatment of bilateral vertical sacral fractures to provide reference for clinical application. METHODS: A finite element model of Tile C pelvic ring injury (bilateral type Denis II fracture of sacrum) was produced. (Tile and Denis are surgeons, who put forward the classifications of pelvic ring injury and sacral fracture respectively.) The bilateral sacral fractures were fixed with a lengthened sacro-iliac screw and a sacro-iliac screw in seven types of models, respectively. The translation and angular displacement of the superior surface of the sacrum in the case of standing on both feet were measured and compared. RESULTS: The stability of one lengthened sacro-iliac screw fixation in the S1 or S2 segment is superior to that of two bidirectional sacro-iliac screws in the same sacral segment; the stability of one lengthened sacro-iliac screw fixation in S1 and S2 segments, respectively, is superior to that of two bidirectional sacro-iliac screw fixation in S1 and S2 segments, respectively; the stability of one lengthened sacro-iliac screw fixation in S1 and S2 segments, respectively, is superior to that of one lengthened sacro-iliac screw fixation in the S1 or S2 segment; the stability of two bidirectional sacro-iliac screw fixation in S1 and S2 segments, respectively, is markedly superior to that of two bidirectional sacro-iliac screw fixation in the S1 or S2 segment and is also markedly superior to that of one sacro-iliac screw fixation in the S1 segment and one sacro-iliac screw fixation in the S2 segment; the vertical stability of the lengthened sacro-iliac screw or the sacro-iliac screw fixation in S2 is superior to that of S1. The rotational stability of the lengthened sacro-iliac screw or sacro-iliac screw fixation in S1 is superior to that of S2. CONCLUSION: S1 and S2 lengthened sacro-iliac screws should be used for the fixation in bilateral sacral fractures of Tile C pelvic ring injury as far as possible and the most stable fixation is the combination of the lengthened sacro-iliac screws of S1 and S2 segments. Even if lengthened sacro-iliac screws cannot be used due to limited conditions, two bidirectional sacro-iliac screw fixation in S1 and S2 segments, respectively, is recommended. No matter which kind of sacro-iliac screw is applied, the fixation combination of S1 and S2 segments is strongly recommended to maximise the stability of the pelvic posterior ring.

Anterior cervical discectomy and interbody fusion by endoscopic approach: a preliminary report.

OBJECT: The authors report the short-term results of anterior cervical discectomy and interbody fusion performed via an endoscopic approach. METHODS: Thirty-six patients who underwent anterior cervical discectomy and fusion (ACDF) performed using endoscopic surgery were selected for this study. The indications for surgery were cervical disc herniation caused by neck injury, spondylotic myelopathy, cervical radiculopathy, and solitary ossification of the posterior longitudinal ligament (OPLL). The involved levels included C3-4, C4-5, C5-6, and C6-7. The working channel was inserted through a 20-mm transverse incision, the protruding discs or area of OPLL were excised for complete decompression, and then an appropriate intervertebral polyetheretherketone fusion cage was implanted. RESULTS: The time spent in surgery was 120 minutes on average (range 50-150 minutes), and the mean blood loss was 55 ml (range 20-140 ml). There were no intraoperative complications and no symptoms of irritation in the laryngopharynx after surgery. However, postoperative hemorrhage of the incision occurred in 1 case. The follow-up period ranged from 26-50 months (mean 38.5 months). Postoperative Japanese Orthopaedic Association and visual analog scale scores improved significantly. CONCLUSIONS: Endoscopic surgery for ACDF can produce satisfactory results in patients with cervical disc herniation, cervical myelopathy, or radiculopathy. The optimal levels for this procedure are C4-5 and C5-6. Compared with a traditional approach, this technique has great advantages in terms of cosmetic results, intraoperative visualization, and postoperative recovery course. Nevertheless, every precaution should be taken to avoid possible complications, such as postoperative hemorrhage.

Extracellular matrix synthesis and ultrastructural changes of degenerative disc cells transfected by Ad/CMV-hTGF-beta 1.

OBJECTIVE: To determine whether the synthesis of proteoglycan, collagen and associated ultrastructure are related to the adenovirus-mediated gene transferred to adult degenerative cells. METHODS: Adenovirus/cytomegalovirus human transforming growth factor-beta 1 (Ad/CMV-hTGF-beta 1) was used to transfect degenerative cells. Antonopulos method, Miamine method and transmission electron microscopy were conducted to study the synthesis of proteoglycan, collagen, and ultrastructure, respectively. Cell cultures were established from the nucleus pulpous and annulus fibrosus tissues, which were taken from surgery. RESULTS: Nucleus pulpous and annulus fibrosus cells were efficiently transduced by the adenoviral vector carrying hTGF-beta 1 gene. The synthesis of proteoglycan and collagen increased compared with the control group (P < 0.05). The metabolism of cells was slightly improved. No significant toxic effects were found. CONCLUSIONS: Expression of hTGF-beta 1 gene is efficient to accelerates proteoglycan synthesis and thus accelerates the improvement of collagen. The function and structure of degenerative cells are improved. Ad/CMV-hTGF-beta 1 may be suitable for treating disc degeneration.

Construction of recombinant adenoviral vector Ad-CMV-hTGFbeta1 for reversion of intervertebral disc degeneration by gene transfer.

OBJECTIVE: To provide a highly efficient adenoviral vector Ad-CMV-hTGFbeta1 for the study of gene therapy for reversion of the intervertebral disc degeneration. METHODS: A newly developed recombinant adenoviral vector construction system was used in the study. The cDNA of hTGFbeta1 was first subcloned into a shuttle plasmid pShuttle-CMV. The resultant plasmid was linearized by digesting with restriction endonuclease PmeI, and subsequently transformed into E.coli. BJ5183 cells with an adenoviral backbone plasmid pAdEasy-1. Recombinants were selected by kanamycin resistance and confirmed by restriction endonuclease analysis. Finally, the recombinant plasmid linearized by PmeI was transfected into 293 cells. Recombinant adenoviruses were generated within 2 weeks. RESULTS: The recombinant adenoviral plasmids were cut by BamHI and PacI respectively, and the diagnostic fragments appeared in 0.8% agarose electrophoresis. The infected 293 cells showed evident cytopathic effect (CPE). The productions of PCR confirmed the presence of recombinant adenovirus. The expression of hTGFbeta1 was verified by immunohistochemical staining. CONCLUSIONS: The successful generation of the adenoviral vector Ad-CMV-hTGFbeta1 and the confirmation of the interest gene expression make it possible for the experimental study of the reversion of the intervertebral disc degeneration by gene therapy.