Qunfeng Guo

Esophagus perforation complicating anterior cervical spine surgery

PurposeTo study the diagnosis and treatment strategy of esophagus perforation complicating anterior cervical spine surgery.MethodsFrom 2000 to 2010, we performed 1,045 cases of anterior cervical surgeries. One developed esophagus perforation. The diagnosis and treatment strategy of this case and the other five patients with esophagus perforation from other hospitals were retrospectively reviewed. For an intraoperative perforation, primary double layer suture was performed. Postoperatively, the patient took nutrition by a nasogastric tube instead of oral intake for one week. For three cases of perforations early in the post-operative period, oral intake was forbidden and nasogastric tube was conducted for nutrition support. The wound was debrided and open drainage was conducted postoperatively. Intravenous broad-spectrum antibiotic therapy was utilized. For perforations at postoperative year 3 and 7, prohibition of oral intake, intravenous broad-spectrum antibiotics therapy, and nasogastric tube nutrition support were all conducted and surgical debridement was performed. In operation, fixation plates and screws were removed, and the edges of the perforation were loosely approximated by synthetic absorbable sutures. Postoperatively, skin wound was kept open for drainage.ResultsAll the perforations healed evenly without secondary complications.ConclusionsWhen a perforation is suspected, imaging techniques should be employed. Surgical treatment facilitates the healing of esophagus perforation. Supportive treatments including prohibition of oral intake, intravenous broad-spectrum antibiotic therapy, feeding with a nasogastric tube were mandatory parts of treatments.

Bilateral C1–C2 Transarticular Screw and C1 Laminar Hook Fixation and Bone Graft Fusion for Reducible Atlantoaxial Dislocation: A Seven-Year Analysis of Outcome

Background Bilateral C1-2 transarticular screw and C1 laminar hook fixation was developed on the basis of transarticular screws fixation. The modified technique has showed a better biomechanical stability than established techniques in previous study. However, long-term (minimum follow-up 7 years) outcomes of patients with reducible atlantoaxial dislocation who underwent this modified fixation technique have not still been reported. Methods A retrospective study was conducted to evaluate the outcome of 36 patients who underwent this modified technique. Myelopathy was assessed using the Ranawat myelopathy score and Myelopathy Disability Index. Pain scores were assessed using Visual Analogue Scale. Radiological imaging was assessed and the following data were extracted: the atlantodental intervals, the space available for cord, presence of spinal cord signal change on T2 weighted image, C1–C2 angle, C2–C7 angle and fusion rates. Findings All patients achieved a minimum seven-year follow up. 95% patients with neck and suboccipital pain improved after surgery; in their Visual Analogue pain scores, there was a greater than 50% improvement in their VAS scores with a drop of 5 points on the VAS (P<0.05). 92% of patients improved in the Ranawat myelopathy grade; the Myelopathy Disability Index assessment showed a preoperative mean score of 35.62 with postoperative mean 12.75(P<0.05). There was not any significant atlantoaxial instability at each follow-up time. The space available for cord increased in all patients. Postoperative sagittal kyphosis of the subaxial spine was not observed. After six months after surgery, bone grafts of all patients were fused. No complications related to surgery were found in the period of follow-up. Conclusions The long-term outcomes of this case series demonstrate that under the condition of thorough preoperative preparations, bilateral C1–C2 transarticular screw and C1 laminar hook fixation and bone graft fusion is a reliable posterior atlantoaxial fusion technique for reducible atlantoaxial dislocation.

Posterior reduction and temporary fixation for odontoid fracture: a salvage maneuver to anterior screw fixation.

Study Design. A prospective study. Objective. To evaluate the outcomes of posterior reduction and temporary fixation using the C1–C2 screw-rod system for odontoid fracture unsuitable for anterior screw fixation. Summary of Background Data. Anterior screw fixation has become the most widely used surgical procedure for the stabilization of odontoid fractures. However, if there is any contraindication for anterior fixation, posterior atlantoaxial fusion is preferred, eliminating the normal rotation of the atlantoaxial complex. Methods. A consecutive series of 22 patients with odontoid fracture unsuitable for anterior screw fixation were involved in this study. Posterior reduction and fixation without fusion using the C1–C2 screw-rod system was performed. Once fracture healing was obtained, instrumentation was removed. The visual analogue scale of neck pain, neck stiffness, American Spinal Injury Association impairment scale, patient satisfaction, and neck disability index were recorded. The range of motion of C1–C2 in flexion-extension and rotation was calculated. Results. The average age at internal fixation surgery was 40.2 ± 11.3 years. The mean duration of follow-up was 41.8 ± 26.8 months. There were no complications associated with instrumentation. All patients returned to their preoperative work. Fracture healing was observed in 21 patients and the instrumentation was removed. After removing the instrumentation, the visual analogue scale was reduced and neck stiffness were relieved (all P < 0.01). Patient satisfaction and neck disability index had improved (all P < 0.01). The range of motion of C1–C2 returned to 4.75°± 1.62° and 25.70°± 5.51° in flexion-extension and in rotation, respectively. No osteoarthritis was observed at the C1–C2 lateral mass joints. Conclusion. Posterior reduction and temporary fixation using the C1–C2 screw-rod system was an optimal salvage maneuver to anterior screw fixation for odontoid fracture. It could effectively avoid the motion loss of C1–C2 caused by posterior atlantoaxial fusion. Level of Evidence: 3

Surgical Treatments of Myelopathy Caused by Cervical Ligamentum Flavum Ossification

OBJECTIVE To present a small case series reporting the outcomes of surgical treatment for myelopathy caused by cervical ossification of the ligamentum flavum (OLF). METHODS The authors assessed 15 cases of myelopathy caused by cervical OLF. Patients were eight women and seven men 37-75 years old (mean age 59.7 years). All patients underwent bilateral laminectomy, and the lesions were removed. The decompression range was confined within the medial sides of the bilateral facets and within the involved segments. Intraoperative specimens were examined histologically to confirm the diagnosis. During the operation, the extent of adherence of the lesions to the dura was recorded. The patients were followed for 3-70 months. Neurofunctional improvements were evaluated with the Japanese Orthopaedic Association (JOA) score. RESULTS Definite adherences were present in 67.7% of all cases. JOA score showed a 71.5% improvement after operation from a preoperative score of 5-8 (mean 6.4) to a postoperative score of 10-14 (mean 13.5). The operative outcomes were satisfactory without extensive decompression of adjacent segments. CONCLUSIONS A high rate of adherence to the dura was observed in patients with myelopathy caused by cervical OLF. Bilateral laminectomy and removal of the lesions, without extensive decompression of adjacent segments, provides an optimistic prognosis.

Multilevel anterior cervical discectomy and fusion with plate fixation for juvenile unilateral muscular atrophy of the distal upper extremity accompanied by cervical kyphosis.

Study Design: A retrospective clinical study was conducted and related literatures were reviewed. Object: This study aimed to evaluate outcome of multilevel anterior cervical discectomy and fusion with plate fixation for juvenile unilateral muscular atrophy of the distal upper extremity accompanied by cervical kyphosis. Summary of Background Data: Juvenile unilateral muscular atrophy of the distal upper extremity is a rare disease. Traditional treatment uses a neck collar to immobilize neck motion. However, if the disease is accompanied by cervical kyphosis, conservative treatment is difficult to correct cervical kyphosis and the prognosis is worsened. Therefore, it is important to initially apply surgical treatment for juvenile unilateral muscular atrophy accompanied with cervical kyphosis. Methods: From March 2008 to May 2010, 4 patients were transferred to our spine medical center because of a history of slowly progressive distal weakness and atrophy of their hands and forearms. Four patients were diagnosed with Hirayama disease accompanied with cervical kyphosis based on their clinical representations and radiologic findings. After conservative treatment failed, these patients underwent multilevel anterior cervical discectomy and fusion with plate fixation. The clinical outcomes were retrospectively evaluated with follow-up ranging from 1.5 to 3 years. Results: The clinical and radiologic follow-up indicated satisfactory clinical relief from symptoms, cervical sagittal alignment and cervical spinal canal volume, for all the patients. Within 6 months after surgery, the JOA score improved from a preoperative average of 14 to a postoperative average of 16.3; JOA recovery rates of all patients were more than good level. The muscle strengths of intrinsic muscles, wrist flexors and extensors, and biceps and triceps muscle improved on average by 1 grade. No complications occurred. Conclusions: Hirayama disease is a rare disease, a proper diagnosis of which can be made based on significant clinical symptoms and neurological imaging (dynamic MRI). The primary results from this study showed the tendency that multilevel anterior cervical discectomy and fusion with plate fixation is a preferred treatment for patients showing anterior effacement and apparent cervical kyphosis.

Tumor Necrosis Factor Alpha Promotes Osteoclast Formation via PI3K/Akt Pathway-Mediated Blimp1 Expression Upregulation†

Tumor necrosis factor alpha (TNF‐α)‐induced osteoclastogenesis have profound effects in states of inflammatory osteolysis such as rheumatoid arthritis, periprosthetic implant loosening, and periodontitis. However, the exact mechanisms by which TNF‐α promotes RANKL‐induced osteoclast formation remains poorly understood. B lymphocyte‐induced maturation protein‐1 (Blimp1) is a transcriptional repressor that plays crucial roles in the differentiation and/or function of various kinds of cells including osteoclasts. A novel mechanism was identified where TNF‐α‐mediated Blimp1 expression, which contributed to RANKL‐induced osteoclastogenesis. It is shown that TNF‐α could promote the level of Blimp1 expression during osteoclast differentiation. Silencing of Blimp1 in osteoclast precursor cells obviously attenuated the stimulatory effect of TNF‐α on osteoclastogenesis. Mechanistically, TNF‐α‐induced Blimp1 expression was markedly rescued by blocking the PI3K/Akt signaling pathway, which suggested that PI3K/Akt signaling was involved in the regulation of TNF‐α‐stimulated Blimp1 expression. Taken together, the results established a molecular mechanism of TNF‐α‐induced osteoclasts differentiation, and provided insights into the potential contribution of Blimp1 in the regulation of osteoclastogenesis by TNF‐α. J. Cell. Biochem. 118: 1308–1315, 2017.

Subaxial Cervical Intradiscal Pressure and Segmental Kinematics Following Atlantoaxial Fixation in Different Angles.

OBJECTIVE To evaluate in a comprehensive biomechanical study the influences of fixed C1-C2 and different C1-C2 angles on the range of motion (ROM) and the intradiscal pressure (IDP) of subaxial cervical spine. METHODS We simulated three-dimensional cervical motions on 8 human specimens with C1-C2 fixed in 3 different angles (neutral position, neutral position -10°, neutral position +10°) following intact analysis in the material test system. The ROM changes of each motion segment and the IDP changes of 4 subaxial motion segments (C2-C3, C3-C4, C4-C5, and C5-C6) were monitored. RESULTS ROM change patterns at all subaxial segments were similar. Fixed C1-C2 led to a significant ROM increase relative to the intact condition during flexion/extension testing. A larger C1-C2 angle (neutral position +10°) caused an additional ROM increase during flexion, whereas a smaller C1-C2 angle (neutral position -10°) induced a further ROM increase during extension. Axial rotation testing revealed the most striking and similar ROM increases in the instrumented groups relative to the intact group. Lateral bending testing did not reveal significant ROM change between the instrumented groups and the intact group. For IDP analysis, C1-C2 fixed in a larger angle (neutral position +10°) caused significant IDP increases at the C2-C3, C3-C4, and C4-C5 levels during flexion. CONCLUSIONS To maintain a physiologic sagittal alignment of subaxial cervical spine, C1-C2 should be fixed in the neutral position or a relatively smaller angle instead of a more lordotic position.

A Validated Finite Element Analysis of Facet Joint Stress in Degenerative Lumbar Scoliosis

OBJECTIVE To develop modified finite element models to simulate degenerative lumbar scoliosis (DLS) based on the normal lumbar spine model and to investigate the facet joint force of the DLS. METHODS A 3-dimensional finite element model of a normal lumbar spine was modified to simulate 3 different Cobb angles conditions (12.3°, 22.2°, and 31.8°). The stresses on the facet joint were calculated on both sides (right and left) of the each vertebra. Changes of stress and asymmetry in contact forces between facet joints in the development of DLS were quantitatively analyzed to better understand the development of DLS and the biomechanical forming mechanism. RESULTS The results show that asymmetric responses of the facet joint forces exist in various postures and that such effect is amplified with larger curve. When the Cobb angle was smaller, the convex side of the facet joints suffered larger force. When the Cobb angle was larger than 20°, the concave side of the facet joints suffered larger force. In the axial-rotation cases, the facet joint compression is less often located on the ipsilateral side than the contralateral side at the same level. CONCLUSIONS With the asymmetric loading, facet joints compressive deformation appears on the concave side, and it decreases in the effect of the facet joints to limit the vertebral rotation and listhesis. Asymmetric loading on facet joint contact forces accelerates asymmetry in the lumbar spine.

Comparison of Clinical Outcomes of Posterior C1-C2 Temporary Fixation Without Fusion and C1-C2 Fusion for Fresh Odontoid Fractures.

BACKGROUND Posterior C1-C2 temporary-fixation technique can spare the range of motion (ROM) of the atlantoaxial joint after odontoid fracture healing. However, few studies analyze the difference in clinical outcome between this technique and posterior C1-C2 fusion technique for new odontoid fracture. OBJECTIVE To verify whether the clinical outcome of the posterior C1-C2 temporary-fixation technique is superior to that of the posterior C1-C2 fusion technique in the treatment of a new odontoid fracture. METHODS Twenty-one of 22 patients who underwent posterior C1-C2 temporary fixation of an odontoid fracture achieved fracture healing and regained motion of the atlantoaxial joint. The functional outcomes of these 21 patients were compared with that of a control group, which consisted of 21 randomly enrolled cases with posterior C1-C2 fixation and fusion. The differences between the 2 groups in the visual analog scale score for neck pain, neck stiffness, Neck Disability Index, 36-Item Short Form Health Survey, and time to fracture healing were analyzed. RESULTS Significantly better outcomes were observed in the temporary-fixation group for visual analog scale score for neck pain, Neck Disability Index, and neck stiffness. The outcomes in the temporary-fixation group was superior to those in the fusion group in all dimensions of the 36-Item Short Form Health Survey. There were no significant differences in fracture healing rate and time to fracture healing between the 2 techniques. CONCLUSION Functional outcomes were significantly better after posterior C1-C2 temporary fixation than after fusion. Temporary fixation can be used as a salvage treatment for an odontoid fracture with an intact transverse ligament in cases of failure of, or contraindication to, anterior screw fixation.

A biomechanical comparison of a novel thoracic screw fixation method: transarticular screw fixation vs traditional pedicle screw fixation.

BACKGROUND AND IMPORTANCE The main therapeutic approach for malignant peripheral nerve sheath tumors (MPNSTs) of the brachial plexus is wide local excision. Sacrifice of some--occasionally all--elements of the brachial plexus often is required to obtain complete resection, and therefore can be associated with significant morbidity. While peripheral nerve repair is commonly used in the setting of traumatic nerve injury, little is known about its potential use in the treatment of MPNST. CLINICAL PRESENTATION We present a patient with an enlarging right neck mass who was diagnosed with MPNST of the brachial plexus. The patient underwent gross total resection of the tumor, requiring sectioning of the upper trunk of the brachial plexus, as well as associated divisions. Following resection, sural nerve grafts were used to connect the C5 nerve root to the anterior division of the upper trunk and the spinal accessory nerve to the suprascapular nerve, whereas a triceps branch of the radial nerve was coapted directly to the anterior division of the axillary nerve. CONCLUSION By 20 months after surgery, the patient had regained significant strength in her upper trunk distribution and demonstrated no evidence of tumor recurrence. Brachial plexus reconstruction offers a potentially valuable surgical adjunct to MPNST treatment.BACKGROUND Transarticular screw fixation is used in the upper cervical and lumbar spine to achieve posterior spinal stability, and its biomechanical performance has been proven to be similar to that of pedicle screw fixation. However, few studies have reported the use of transarticular screw fixation in the upper thoracic spine. OBJECTIVE To biomechanically compare transarticular screws with pedicle screws in short-term cyclic loading in the upper thoracic spine. METHODS Eight fresh human cadaveric spine specimens (T1-T3) were harvested and tested for 6 cycles in flexion, extension, lateral bending, and torsion in their intact condition. Each specimen was then destabilized and restabilized with 3 fixation methods: the pedicle screw/rod construct, the transarticular screw/rod construct, and transarticular screws alone. The instrumented specimens were reteted with the same protocol. RESULTS All fixation systems reduced the range of motion significantly with respect to flexion, extension, lateral bending, and axial rotation (P < .01). However, no significant difference was observed between the 3 instrumented groups. CONCLUSION This biomechanical study demonstrates in vitro that transarticular screws and pedicle screws have statistically similar biomechanical stability in a noncorpectomy model. Posterior transarticular screws may be an alternative for internal fixation in the upper thoracic spine.