Bin Ni

Direct repair of defect in lumbar spondylolysis and mild isthmic spondylolisthesis by bone grafting, with or without facet joint fusion.

Abstract. Forty-six patients with lumbar spondylolysis and mild isthmic spondylolisthesis were managed with direct repair of the defect with or without facet joint fusion in the affected segment. There were 24 males and 22 females, ranging in age from 15 to 56 years (average, 38.2 years). These patients had experienced clinical symptoms due to spondylolysis for between 4 months and 20 years (average, 5.3 years). Of 46 patients, 28 had no spondylolisthesis, 11 had Meyerding grade I vertebral slippage and 7 had grade II. Direct repair of 98 defects was performed on these patients. Twenty-six patients, in whom the disc adjacent to the defect was determined as degenerative by magnetic resonance imaging (MRI), simultaneously underwent facet joint fusion; 17 in one segment and 9 in two segments. The average period of follow-up was 50 months (24–92 months). Ninety-four defects achieved bony healing. As a result, 28 patients were graded as having an excellent outcome, 15 good, and 3 fair. Bone grafting in the defects achieves union between the loose lamina and the anterior element of lumbar vertebrae, and reconstructs the anatomic structure and physiologic functions of the lumbar vertebrae. There was no significant difference in outcome between the spondylolytic/spondylolisthetic patients with non-degenerative disc, who were treated with direct repair of defect only, and those with degenerative disc, who additionally underwent a fusion procedure (P>0.05). The present series demonstrates a satisfactory result and a high rate of bony healing of the pars defect by this operative procedure in patients with lumbar spondylolysis and mild isthmic spondylolisthesis. Preoperative assessment of the disc degeneration with MRI is of great assistance in making the protocol choice of whether to opt for fusion.

Surgical treatment of nonunited fractures of the odontoid process, with special reference to occipitocervical fusion for unreducible atlantoaxial subluxation or instability

Abstract Fifty-seven consecutive patients treated surgically for nonunited fractures of the odontoid process were reviewed. All patients presented late, exhibiting neurological deficits subsequent to nonunion. Delay in presentation was between ¶6 and 120 months (mean 32 months) after the original injury, due to missed diagnosis or inappropriate management. Seven patients who were reduced in traction underwent a Gallie atlantoaxial fusion. In the remaining 50 patients who were unreducible, an occipitocervical arthrodesis was performed. They were followed up for a minimum of 2 years, except one who died from postoperative respiratory failure. All patients obtained a solid bony union, including two in whom nonunion occurred following atlantoaxial fusion, and occipitocervical fusion was added as a rescue. Thirty-eight patients achieved excellent neurological recovery, nine still had some disability, five retained their neurological deficits and two reported a deterioration. In two patients, a recurrence in a traumatic episode was experienced long after a resolution. Our findings demonstrate that occipitocervical arthrodesis is preferable for unreducible subluxation or instability of atlantoaxial articulation in nonunion of odontoid fractures.

Application of liposome-encapsulated hydroxycamptothecin in the prevention of epidural scar formation in New Zealand white rabbits.

BACKGROUND CONTEXT Epidural adhesion and fibrosis attribute to the prevalence of pain in normal wound healing after laminectomy surgery. Hydroxycamptothecin (HCPT), an antitumor drug, has proved to be effective in preventing fibroblast proliferation and reducing epidural adhesion after laminectomy in vivo animal study. However, HCPTs disadvantages, such as poor solubility and short half-life, limit its application clinically. Compared with HCPT, the liposome-encapsulated HCPT (L-HCPT) could reduce epidural fibrosis by preventing the proliferation of fibroblast in the scar tissues with longer half-life and increased solubility. PURPOSE To evaluate the suitability of L-HCPT in the laminectomy models on rabbits and to explore the mechanisms in the prevention of epidural scar formation. STUDY DESIGN An original investigation that characterizes the novel delivery system in the combinational application of HCPT and liposome (L-HCPT). PATIENT SAMPLE The sample comprises 24 mature New Zealand white adult rabbits. METHODS Lumbar laminectomies at L4 and L6 with an L5 disc injury were performed on 24 mature New Zealand white adult rabbits. The rabbits were then randomized into three groups. In Group I, the laminectomy site was treated with a cotton pad soaked with HCPT solution (1 mg/mL) for 5 minutes (HCPT group) and was flushed with saline completely. In Group II, 1 mL of L-HCPT was seeded on the laminectomy area (L-HCPT group). In Group III, the laminectomy area was flushed with saline before wound closure (control group). After 28 days, the animals underwent magnetic resonance imaging. The animals were euthanized; the spinal section was removed for macroscopic evaluation, and hydroxyproline in the scar tissue was quantified. RESULTS Operation in all the animals yielded a reproducible laminectomy, without complication or mortality. In the laminectomy sites treated with L-HCPT, the dura mater was clean without any evident adhesion. Magnetic resonance imaging analysis implied that L-HCPT treatment could reduce the epidural scar significantly compared with saline control group, which was further proved by the decreased concentration of hydroxyproline in the scar tissues. CONCLUSION These results demonstrate that the treatment of postlaminectomy wounds in rabbits with L-HCPT reduces the severity of adhesion.

Biomechanical assessment of bilateral C1 laminar hook and C1-2 transarticular screws and bone graft for atlantoaxial instability.

StudyDesign In vitro biomechanical test was conducted to compare the stability of 5 different atlantoaxial posterior fusion techniques. Objective To evaluate the biomechanical stability of an atlas laminar hook combined with transarticular (TA) screws relative to 4 different conventional fusion techniques. Summary of Background Data The atlantoaxial instability caused by fractures, rheumatoid arthritis, congenital deformity, or traumatic lesions of the transverse ligament often result in acute or chronic spinal cord compression, a possible threat to a patients life. Posterior atlantoaxial fixations are used to reconstruct the stability of atlantoaxial articulation. Conventional posterior atlantoaxial fixations are associated with high rates of pseudoarthrosis and carry the potential risk of neurologic complication. TA screw fixation can provide an excellent biomechanical stability. As a modified 3-point fixation technique, the bilateral C1-2 TA screws have been combined with C1 laminar hook and bone grafts. This modified technique had carried good clinical outcomes. Methods Eight human specimens (C0-C4) were loaded nondestructively with pure moments and the range of motion at the level of C1-C2 was measured. Eight specimens were implanted with each of the following techniques, respectively: Gallie fixation, C1-2 TA screw fixation combined with Gallie fixation, C1-2 TA screw fixation, C1 laminar hook combined with C1-2 TA screw fixation plus bone grafts, and the C1 lateral mass screws in the atlas combined with C2 isthmic screws in axis. Results Although the C1-2 TA screws best restricted lateral bending and axial rotation, the modified 3-point fixation technique additionally restricted flexion-extension and provided the excellent stability. Differences in axial rotation and lateral bending (with±1.5 Nm load) were observed when the 3-point fixation techniques (TA+Gallie and TA+hook) were compared with atlas lateral mass screws in the atlas combined with isthmic screws in axis. Conclusions The modified C1 laminar hook combined with C1-2 TA screws and bone graft fixation provided the best biomechanical stability. The C1 lateral mass screws in the atlas combined with isthmic screws in axis fixation is a sound alternative when the C1-2 TA screw fixation is not feasible.

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.

Simultaneous ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum causing upper thoracic myelopathy in DISH: case report and literature review.

A rare case of a 44-year-old Chinese male with diffuse idiopathic skeletal hyperostosis (DISH) and simultaneous ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) at T1–2 causing thoracic myelopathy is reported herein. Posterior decompression without extirpating the OPLL was performed at T1–2. Postoperatively, symptoms were greatly improved, with remaining hyperreflexia and Grade 4/5 muscle strength in the lower extremities. The Japanese Orthopedic Association score improved from 5 preoperatively to 9 at final follow-up. The presence of a cyst due to leakage of cerebrospinal fluid was confirmed by MRI at day 27, but it resolved after conservative management. The clinical manifestation of DISH, the relationship among DISH, OPLL, and OLF, and management of thoracic myelopathy due to OPLL and OLF were reviewed.

Estrogen inhibits RANKL-induced osteoclastic differentiation by increasing the expression of TRPV5 channel.

The inhibitor effect of estrogen on osteoclasts differentiation is very important in the etiology of estrogen protecting the adult skeleton against bone loss. However, the precise molecular events underlying the effect of estrogen on osteoclasts differentiation are not known. Recent studies implicated an important role of transient receptor potential vanilloid 5 (TRPV5) in osteoclast differentiation and bone resorption. Furthermore, some studies have confirmed that estrogen is involved in the regulation of calcium ion (Ca2+) influx in many cells via TRPV5 channel. Therefore, we hypothesize that TRPV5 channel may be implicated in the process of estrogen‐inhibited osteoclastogenesis and bone resorption. Western blot, quantitative real‐time PCR, tartrate‐resistant acid phosphatase (TRAP) staining, and pit formation assay were employed to investigate the role of TRPV5 in estrogen decreasing osteoclast differentiation and bone resorption. We found that the expression of TRPV5 is significantly down‐regulated during estrogen deficiency‐induced osteoclastogenesis. Furthermore, TRAP staining and pit formation assay showed that the depletion of TRPV5 significantly blocks the inhibitor effects of estrogen on osteoclasts differentiation and bone resorption activity. Further studies confirmed that estrogen regulates the expression of TRPV5 channel via estrogen receptor. Based on these results above, we can draw conclusion that TRPV5 may contribute to the process of estrogen‐inhibited osteoclastogenesis and bone resorption activity. J. Cell. Biochem. 115: 651–658, 2014.

Combined anterior C2-C3 fusion and C2 pedicle screw fixation for the treatment of unstable hangman's fracture: a contrast to anterior approach only.

Study Design. A retrospective clinical study was used to evaluate the effect of a new surgical treatment of the hangmans fractures. Objective. To determine the treatment efficacy of combined anterior C2-C3 reduction and fusion and posterior compressive C2 pedicle screw fixation for the management of unstable hangmans fractures. Summary of Background Data. The classification of hangmans fractures as proposed by Levine-Edwards was used to classify and guide the treatment of these injuries. Most of these fractures respond to a variety of conservative therapies, but recently, earlier surgery has been increasingly advocated by authors from several countries for the rapid stabilization of these fractures. If surgery is indicated, an anterior approach using a C2-C3 reduction and fusion is preferred usually. Another well-accepted surgical method is the direct transpedicular osteosynthesis by the dorsal approach. However, there was rare report of the combined use of these 2 techniques. Methods. A group of 45 surgical patients were all diagnosed with radiograph, magnetic resonance imaging (MRI), and 3D CT scans. Initial and final radiographs were measured for anterior translation and angulation of the C2-C3 complex. Initial external skull traction with extension was used in all patients after admission to reduce the fracture. Then an anterior C2-C3 discectomy followed by an interbody fusion and locking plate fixation was performed. Intraoperative reduction was confirmed by fluoroscopic control. About 29 patients therefore received anterior surgeries only since satisfactory reduction was achieved during the procedure. For the 16 patients who had persistent large residual gaps after the anterior procedure, additional same stage posterior C2 compressive pedicle screws were placed. Clinical and radiologic comparisons were performed in these 2 groups. Results. The follow-up ranged from 24 to 54 months, with an average 33.6 months. There was radiographic evidence of continuity of the fracture and the bone graft seen at 4.7 months on average. Neck pain and neurologic deficits resolved in nearly all patients after surgery. The anterior translation of anterior-posterior surgery group decreased more significant compared to anterior surgery group, although with no statistical significance. The fractures were closed with a slight gap no more than 2 mm in anterior-posterior surgery group. The residual kyphosis in anterior-posterior surgery group was still a little larger than it in anterior surgery group. No internal fixation failures or infections were observed. Conclusion. We believe that the need for single stage 360° fusion of hangmans fractures can be somewhat predicted by a combination of high resolution imaging. For hangmans fractures with significant deformity and gapping, it is our experience that immediate single-stage anterior-posterior reduction, instrumentation, and arthrodesis achieve superior postoperative reduction and long-term functional outcomes.

Anterior decompression and interbody fusion with BAK/C for cervical disc degenerative disorders.

Study Design A retrospective clinical study of 64 patients who underwent anterior cervical discectomy and fusion (ACDF) with BAK/C for disc degenerative disorders. Objective To evaluate the long-term outcome of BAK/C in the treatment of cervical disc degenerative disorders. Summary of Background Data ACDF has been demonstrated to be effective in the treatment of cervical disc degenerative disorders. BAK/C, a kind of thread cage widely used for interbody fusion in the lumbar spine, was used in the cervical spine to avoid the donor site complications of traditional autologous bone graft. Methods Sixty-four patients with cervical disc degenerative disorders underwent ACDF with BAK/C technique in our institution between September 1997 and December 2000. All the patients were followed up for at least 6 years. The changes of segmental stability, bone fusion, cervical lordosis, and intervertebral height on radiographs were evaluated in detail immediately after operation, at 6 and 12 months postoperatively, and yearly thereafter. The clinical outcome of neurologic improvement and pain relief was also investigated. Results Solid fusion was achieved at 1 year postoperatively in all patients, and the segmental stability was maintained during the whole follow-up. The cervical lordosis and intervertebral height were well restored immediately after operation, and gradually lost during the follow-up. Especially, the anterior height of intervertebral space decreased significantly after 1 year, when compared with the anterior height immediately after operation. BAK/C subsidence was observed in 9 patients, including 5 with 1-level fusion, 1 with 2–separated-level fusion, and 3 with 2–adjacent-level fusion, according to the standard of loss of intervertebral height more than 3 mm. BAK/C fusion was generally effective in the treatment of cervical disc degenerative disorders, according to the evaluation of neurologic improvement and pain relief. However, neck pain tended to reoccur in the patients with cage subsidence, and 2 of them even needed revision surgery because of the recurrence of myelopathy and progressive neck pain. Conclusions Although BAK/C technique was generally effective and safe in the treatment of cervical disc degenerative disorders, the pitfalls of cage design resulted in the disability of maintenance of cervical lordosis and intervertebral height in the long-term follow-up. Cage subsidence, which tended to develop in the patients with 2-level fusion, was possibly responsible for the recurrence of neck pain.

Glucocorticoid Induced Osteoblast Apoptosis by Increasing E4BP4 Expression via Up-regulation of Bim

It is well known that glucocorticoid (GC)-induced bone loss is caused primarily by hypofunction and apoptosis of osteoblasts. However, the precise molecular events underlying the effect of GC on osteoblast apoptosis are not fully understood. Recent studies implicated an important role of E4BP4 in the regulation of osteoblast apoptosis and differentiation. Furthermore, E4BP4 is a GC-regulated gene required for GC-induced apoptosis in many cells. Therefore, we hypothesize that E4BP4 may be implicated in the process of GC-induced osteoblast apoptosis. Western blot, reverse-transcription-PCR, flow cytometry, and Hoechst 33258 staining were employed to investigate the role of E4BP4 in dexamethasone (DEX)-induced osteoblast apoptosis. We found that the expression of E4BP4 is significantly up-regulated in osteoblasts exposed to DEX. Furthermore, the depletion of E4BP4 significantly decreased DEX-induced osteoblast apoptosis. In addition, E4BP4 plays a crucial role in GC-evoked apoptosis of osteoblasts by enabling induction of Bim. On the basis of these results above, we can draw the conclusion that E4BP4 may contribute to the process of DEX-induced osteoblast apoptosis.