Synthesis of pyrazino[1,2-b]indazoles via cascade cyclization of indazole aldehydes with propargylic amines.

An efficient intermolecular annulation of indazole aldehydes with propargylic amines has been developed for the synthesis of pyrazinoindazoles under catalyst- and additive-free conditions. This straightforward methodology was found to feature a wide substrate scope, high atom economy and environmental advantages. The bioactivity results of these new pyrazino[1,2-b]indazoles showed that some of them exhibited significant antifungal activity.

Synthesis and anti-gastric cancer activity evaluation of novel triazole nucleobase analogues containing steroidal/coumarin/quinoline moieties.

A series of novel triazole nucleobase analogues containing steroidal/coumarin/quinoline moieties have been synthesized based on copper-catalyzed azide-alkyne cycloaddition (CuAAC). The anti-cancer activity of the new triazole nucleobase analogues was studied in gastric cancer cell lines (MGC-803, SGC-7901) and normal gastric epithelial cells (GES-1) in vitro. Some of the synthesized compounds could significantly inhibit the proliferation of these tested cancer cells. Among the tested compounds, compound 20c demonstrated good anti-proliferation activity against MGC-803 cells (IC50 = 1.48 µM) and SGC-7901 (IC50 = 2.28 µM) cells as well as the best selectivity between the cancer and normal cells. Further mechanistic studies indicated that compound 20c could down-regulate the expression of TGF ß1 both in the tested gastric cancer cell lines and inhibit the cell migration and invasion. The results of the study indicate that compound 20c could be used as a promising skeleton for anti-gastric cancer agents with improved efficacy and less side effects.

Three-Dimensional-Printed Individualized Guiding Templates for Surgical Correction of Severe Kyphoscoliosis Secondary to Ankylosing Spondylitis: Outcomes of 9 Cases.

OBJECTIVE: To report the outcomes of severe kyphoscoliosis secondary to ankylosing spondylitis (AS) corrected with 3D-printed individualized guiding templates. METHODS: Computed tomography (CT) data of patients with severe kyphoscoliosis secondary to AS were used to reconstruct 3D models of the spine and to develop a surgical plan. An asymmetric wedge pedicle subtraction osteotomy (PSO) was simulated using medical computer design software. Before the actual surgery, continual surgical simulations were performed until the most suitable one was obtained, and personalized guiding templates were manufactured for the anticipated PSO. During operation, the osteotomy plane and trajectories for the pedicle screws were positioned by the designed patient-specific 3D-printed guiding templates. RESULTS: In this study, we reviewed 9 patients who underwent correction of kyphoscoliosis using a 3D-printed individualized guiding template and were followed for a median of 21.4 months (range, 9-36 months). The average correction at the site of osteotomy was 65.9°. No patient experienced severe complications, such as misplaced pedicle screws or neurologic complications. At the last follow-up, no patient exhibited implant dysfunction on radiography. CONCLUSIONS: Preoperative surgical simulation using 3D-printed templates is a viable technique that enables surgery to meet both patient- and surgeon-specific requirements for correction of severe thoracolumbar kyphoscoliosis. These 3D-printed templates can guide the performance of planned PSO to provide functional restoration of severe kyphoscoliosis secondary to AS.

Design, synthesis and biological evaluation of new steroidal ß-triazoly enones as potent antiproliferative agents.

ß-Triazoly enones are biologically interesting scaffolds, incorporation of such scaffolds into the steroid nucleus may generate new bioactive steroids and further enrich structural types of steroids. In this work, a series of new steroidal ß-triazoly enones were synthesized based on click chemistry and Claisen-Schmidt condensation reaction and further evaluated for their antiproliferative activity against a panel of cancer cells. Most of these compounds showed better potency against PC-3 and MGC-803 cells. Particularly, compound 5a inhibited PC-3 and MGC-803 cells potently with the IC50 values of 1.61 and 1.16 µM, respectively, and was less toxic toward GES-1 with an IC50 value of 20.72 µM. Further mechanistic studies showed that compound 5a inhibited migration and invasion of MGC-803 and PC-3 dose-dependently. Treatment with compound 5a varied mRNA levels and protein expression of EMT markers in both cells. Collectively, the steroidal ß-triazoly enones could be potentially utilized to develop new anticancer agents with the ability of inhibiting cell migration and invasion.

Expert consensus for PVCR in severe, rigid and angular spinal deformity treatment: The Kunming consensus.

In the past decades, an increasing number of surgeons started using posterior vertebral column resection (PVCR) to treat severe, rigid and angular spinal deformities. Little high-level evidence is available to guide surgical treatment. The aims of our study were to identify important surgical strategies and key technical points of Chinese experts who have extensive experience in the management of severe, rigid and angular spinal deformities using PVCR, and to standardize and unify the current core concepts. Workgroups of consensus were formed by selecting nationwide representing experts and comprehensive consultations. Eight task forces for major issues were established, then retrieval of literature, collection of expert opinions and writing of review articles were carried out. A modified Delphi process was chosen in round-table forum with three face-to-face meetings. Consensus was reached with items graded more than seven points including: indications and contraindications of PVCR; review PVCR in the evolution of spinal osteotomies; The corrective mechanism and safety of spinal cord; monitoring and responses of spinal cord crisis; characteristics and therapeutic outcome of pulmonary function; management of bleeding during PVCR; relationship of pedicle screw insertion and spinal cord safety; and analysis of non-neurologic complications and prevention strategies. In conclusion, The essential properties regarding PVCR procedure are tightly linked with various factors such as medical and surgical indication, range and level of vertebral column resection, strategies of correction, corrective efficiency and control of neurological risk. PVCR is used mainly for severe, rigid spinal deformity that is not manageable by other osteotomy techniques.

[Case-control study of therapeutic effects between extreme lateral interbody fusion and conventional posterior operation for the treatment of upper lumbar disc herniation].

OBJECTIVE: To evaluate the clinical outcomes between extreme lateral interbody fusion and conventional posterior operation in the treatment of upper lumbar disc herniation. METHODS: Among 60 patients with upper lumbar disc herniation were treated with extreme lateral interbody fusion(XLIF) or conventional posterior operation from June 2010 to December 2014, 30 patients(19 males and 11 females) were treated with XLIF (XLIF group); and the other 30 patients(17 males and 13 females) were treated with conventional posterior operation (conventional group). In XLIF group, the lesions occurred at T12L1 segments in 2 patients, at L1,2 segments in 6 patients, at L2,3 segments in 10 patients, and at L3,4 segment in 12 patients. In conventional group, the lesions occurred at T12L1 segments in 1 patient, at L1,2 segments in 6 patients, at L2,3 segments in 8 patients, and at L3,4 segment in 15 patients. Operative incision lengths, time, blood loss, postoperative draining volume, hospital stays were recorded. Pre-and post-operative visual analogue score(VAS) and Japanese Orthopedic Association(JOA) were compared between two groups. According to the image data, the intervertebral fusion device was observed to be displaced and the rate of interbody fusion was analyzed. RESULTS: All the patients were followed up, and the duration ranged from 12 to 48 months, with an average of 29 months. The complications included 2 femoral nerve damage in XLIF group (postoperative recovery within 3 months) and superficial incision infection in conventional group(cured by anti-infection). There were no patients with cerebrospinal fluid leakage(CSFL), cauda equina injuries or functional deterioration in the nerve root of lower limbs. In the XLIF group: the operative time was (65.6±20.5) minutes, blood loss was (48.8±15.3) ml, postoperative draining volume was 0 ml. In the conventional group: the operative time was (135.2±33.9) minutes, blood loss was (260.3±125.7) ml, postoperative draining volume was (207.1±50.2) ml. The operative time, blood loss, postoperative draining volume in XLIF group were less than those in the conventional group(P<0.05). The JOA and VAS score were significantly improved in both groups during the follow-up period compared with those before operation(P<0.05). But the difference of the JOA and VAS score between the two groups 1, 6, and 24 months after surgery had not significant differences(P>0.05). There were no significant differences in the fusion rate between the two groups 6 and 12 months after operation(P>0.05). CONCLUSIONS: The XLIF fusion for the treatment of upper lumbar disc herniation has several advantages such as minimal invasive, stable vertebral plate, less complications and postoperative fusion rate, which has a better clinical effect.

An 11-Year Review of the TARP Procedure in the Treatment of Atlantoaxial Dislocation.

STUDY DESIGN: Retrospective study. OBJECTIVE: The aim of the study was to introduce the surgical techniques and evaluate the clinical outcomes of transoral atlantoaxial reduction plate (TARP) for the treatment of atlantoaxial dislocation. SUMMARY OF BACKGROUND DATA: Researchers have reported on transoral plate internal fixation for the treatment of irreducible atlantoaxial dislocation (IAAD) without long-term follow-up and detailed clinical experience. METHODS: The clinical records of 388 patients with atlantoaxial dislocation (IAAD, 340 cases; fixed atlantoaxial dislocation [FAAD], 48 cases) who received the TARP procedure from April 2003 to September 2014 were retrospectively reviewed. They were treated separately with TARP-I or TARP-II (82 cases), TARP-III (248 cases), or TARP-IV (58 cases). X-ray and magnetic resonance imaging were used to evaluate the efficacy of reduction and the degree of decompression, respectively. The long-term clinical outcome was evaluated by Japanese Orthopaedic Association scoring and the Symon and Lavender standard. RESULTS: Immediate reduction was achieved for all the patients with IAAD (340/340), whereas anatomical reduction was achieved for 98.2% of patients (334/340). Anatomical reduction was achieved in 87.5% of patients with FAAD (42/48). The average degree of spinal cord decompression ranged from 75% to 100% with an average of 88.4%. The clinical data of 106 patients were evaluated in the latest follow-up (12-108 mo, average 60.5 mo). The average spinal cord improvement rate by Japanese Orthopaedic Association scoring was 62.1%. According to the Symon and Lavender standard, there were 85 cases rated as markedly effective, 104 cases as effective, and 2 cases as noneffective. The overall markedly effective rate was 80% and the effective rate was 98%. CONCLUSION: The TARP procedure showed good anterior atlantoaxial release, reduction, decompression, and internal fixation for patients with IAAD and FAAD through a single anterior approach. It has the advantages of three-dimensional immediate atlantoaxial reduction and sufficient decompression. LEVEL OF EVIDENCE: 3.

Treatment of irreducible atlantoaxial dislocation using the transoral atlantoaxial pedicle screw technique. A report of 10 cases.

OBJECTIVE: The purpose of this work is to evaluate the outcome of the transoral atlantoaxial pedicle screw technique for the treatment of irreducible atlantoaxial dislocation (IAAD). PATIENTS AND METHODS: A total of 10 patients with IAAD were treated using the transoral atlantoaxial pedicle screw technique. We compared preoperative and postoperative JOA (Japanese Orthopedic Association) scores and observed bone graft fusion rate of the atlantoaxial joint, and examined whether our technique was suitable for the treatment of IAAD. RESULTS: The mean preoperative and postoperative JOA scores (9.2 ± 0.63 and 12.9 ± 0.73, respectively) were significantly different (P < 0.05). The atlantoaxial rigid bony fusion rate was 100 % in 10 cases. All cases were followed up for an average of 5.1 years (range 3.5-6 years). CONCLUSION: The transoral atlantoaxial screw reconstruction plate technique is a novel surgical technique for the treatment of IAAD in upper cervical diseases.

The development and evaluation of individualized templates to assist transoral C2 articular mass or transpedicular screw placement in TARP-IV procedures: adult cadaver specimen study.

OBJECTIVES: The transoral atlantoaxial reduction plate system treats irreducible atlantoaxial dislocation from transoral atlantoaxial reduction plate-I to transoral atlantoaxial reduction plate-III. However, this system has demonstrated problems associated with screw loosening, atlantoaxial fixation and concealed or manifest neurovascular injuries. This study sought to design a set of individualized templates to improve the accuracy of anterior C2 screw placement in the transoral atlantoaxial reduction plate-IV procedure. METHODS: A set of individualized templates was designed according to thin-slice computed tomography data obtained from 10 human cadavers. The templates contained cubic modules and drill guides to facilitate transoral atlantoaxial reduction plate positioning and anterior C2 screw placement. We performed 2 stages of cadaveric experiments with 2 cadavers in stage one and 8 in stage two. Finally, guided C2 screw placement was evaluated by reading postoperative computed tomography images and comparing the planned and inserted screw trajectories. RESULTS: There were two cortical breaching screws in stage one and three in stage two, but only the cortical breaching screws in stage one were ranked critical. In stage two, the planned entry points and the transverse angles of the anterior C2 screws could be simulated, whereas the declination angles could not be simulated due to intraoperative blockage of the drill bit and screwdriver by the upper teeth. CONCLUSIONS: It was feasible to use individualized templates to guide transoral C2 screw placement. Thus, these drill templates combined with transoral atlantoaxial reduction plate-IV, may improve the accuracy of transoral C2 screw placement and reduce related neurovascular complications.

The development and evaluation of individualized templates to assist transoral C2 articular mass or transpedicular screw placement in TARP-IV procedures: adult cadaver specimen study

OBJECTIVES: The transoral atlantoaxial reduction plate system treats irreducible atlantoaxial dislocation from transoral atlantoaxial reduction plate-I to transoral atlantoaxial reduction plate-III. However, this system has demonstrated problems associated with screw loosening, atlantoaxial fixation and concealed or manifest neurovascular injuries. This study sought to design a set of individualized templates to improve the accuracy of anterior C2 screw placement in the transoral atlantoaxial reduction plate-IV procedure. METHODS: A set of individualized templates was designed according to thin-slice computed tomography data obtained from 10 human cadavers. The templates contained cubic modules and drill guides to facilitate transoral atlantoaxial reduction plate positioning and anterior C2 screw placement. We performed 2 stages of cadaveric experiments with 2 cadavers in stage one and 8 in stage two. Finally, guided C2 screw placement was evaluated by reading postoperative computed tomography images and comparing the planned and inserted screw trajectories. RESULTS: There were two cortical breaching screws in stage one and three in stage two, but only the cortical breaching screws in stage one were ranked critical. In stage two, the planned entry points and the transverse angles of the anterior C2 screws could be simulated, whereas the declination angles could not be simulated due to intraoperative blockage of the drill bit and screwdriver by the upper teeth. CONCLUSIONS: It was feasible to use individualized templates to guide transoral C2 screw placement. Thus, these drill templates combined with transoral atlantoaxial reduction plate-IV, may improve the accuracy of transoral C2 screw placement and reduce related neurovascular complications. .

Application of three-dimensional model in the management of irreducible atlanto-axial dislocation.

OBJECTIVE: The aim of this study was to describe the application of the rapid prototyping (RP) life-size 3-dimensional model used to improve accuracy of screw insertion in irreducible atlanto-axial dislocation (IAD). METHODS: The study included 10 patients with IAD. All patients were assessed using the Japanese Orthopedic Association (JOA) score. Radiographs, MRI and CT were conducted during the preoperative and postoperative procedure. A 3D RP model was created for each patient. The model was used to obtain detailed information of each pedicle and used as an intraoperative reference. Assisted by the model, transoral atlanto-axial reduction plate fixation was performed in each case. RESULTS: The average operation time was 145 (range: 90 to 180) minutes and average blood loss was 120 (range: 60 to 250) ml. JOA scores improved after surgery. All 40 transoral pedicle/lateral mass screws were placed without serious complications or internal fixation failure. Postoperative radiographs and CT scan showed 38 transoral pedicle/lateral mass screws located in the pedicle tracts. Satisfactory reduction was achieved in 95% of screws. Two screws perforated the lateral wall of the C2 pedicles in an extremely narrow pedicle case. No neurologic sequelae or vertebral artery injury were detected. CONCLUSION: The RP technique is effective and reliable in achieving an accurate and safe screw insertion during IAD surgery, especially in anatomically abnormal cases.

Clinical application of computer-aided design-rapid prototyping in C1-C2 operation techniques for complex atlantoaxial instability.

STUDY DESIGN: This is a retrospective clinical study. OBJECTIVE: To evaluate the clinical efficacy of computer-aided design-rapid prototyping (CAD-RP) techniques in surgical treatments for atlantoaxial instability (AAI). SUMMARY OF BACKGROUND DATA: The complexity of the upper cervical anatomic structures makes the procedures for the treatment of AAI particularly challenging for surgeons. The present study represents a series of C1-C2 surgery for AAI aided by CAD-RP. METHODS: A total of 49 patients (21 men and 28 women) with AAI were treated in our department. According to the use of the CAD-RP technique, the patients were divided into RP group and No RP group. Preoperative CT scans of the upper cervical spine were performed for each patient. For the RP group, physical RP models of the upper cervical spine were manufactured from the 3-dimensional CT data and were used for intraoperative guidance. Personalized surgeries were performed for each case of the 2 groups. The screw malposition rate, frequency of using intraoperative fluoroscopy, operation time, blood loss, and improvement of neurological function were compared between the 2 groups. The mean follow-up duration was 32 months (range, 24-50 mo). RESULTS: The operations were successfully performed in 48 cases expect for 1 case in the No RP group. A total of 204 screws were placed. The intraoperative fluoroscopy frequency and operation time were significantly lower in the RP group than that in the No RP group in both posterior and anterior approaches, whereas the screw malposition rate showed no difference between the 2 groups for both approaches. After the operation, 48 cases achieved satisfactory decompression of the cervical cord and repositioning of the atlantoaxial spine. During follow-up, 47 cases presented improvements in the spinal nerve function within 2 years. CONCLUSIONS: CAD-RP techniques have significant benefits for surgeons providing personalized treatments for AAI, especially cases with complicated deformities.

Anterior pedicle screw fixation of C2: an anatomic analysis of axis morphology and simulated surgical fixation.

STUDY DESIGN: Human cadaveric study measuring the morphology of C2 vertebra, description of anterior placement of pedicle screw with post-fixation computed tomography (CT) analysis. OBJECTIVE: To assess the potential feasibility and safety anterior placement of C2 pedicle screws. SUMMARY OF BACKGROUND DATA: Posterior pedicle screw fixation has become an established technique for upper cervical reconstruction. To our knowledge few reports in the previous literature have described the placement of or anatomy related to anteriorly approach C2 pedicle screws. METHODS: The morphology of 60 human C2 vertebrae was measured directly to assess the size, position, and relative approach angle of the pedicles from an anterior perspective. In an additional 20 cadaveric cervical spines, bilateral 3.5 mm titanium C2 pedicle screws were placed and analyzed for pedicle morphology and placement accuracy with thin cut, 1 mm axial CT. RESULTS: The mean C2 pedicle width measured directly and by CT scan was 7.8 and 6.6 mm, and the average length of the right and left pedicle was 26.4 and 25 mm, respectively. The mean transverse angle (α) was 17.6° and 21.4°, whereas declination angle (ß) anterior to posterior was 13.8° and 10.6°, respectively. CONCLUSIONS: Quantitative data regarding C2 pedicle shape and location with respect to the anterior placement of pedicle screws have not been previously reported. This study indicates that anterior placement of 3.5 mm C2 pedicle screws through a transoral approach may be both feasible and safe and also provides an important anatomic analysis that may guide clinical application.

Transoral atlantoaxial reduction plate internal fixation with transoral transpedicular or articular mass screw of c2 for the treatment of irreducible atlantoaxial dislocation: two case reports.

STUDY DESIGN: Retrospective report of two surgical cases and review of the literature. OBJECTIVE: To report the clinical application of transoral atlantoaxial reduction plate (TARP) internal fixation with a novel technique of transoral transpedicular or articular mass screw of C2 in the treatment of irreducible atlantoaxial dislocation and basilar invagination with ventral spinal cord compression. SUMMARY OF BACKGROUND DATA: Current surgical treatments for IAAD have various disadvantages, such as posterior decompression followed by atlantoaxial or occipitocervical fusion with unsatisfactory decompression, transoral decompression, and one-stage posterior instrumentation needing two approaches although with satisfactory decompression, resection of dens and/or clivus with potential risk of spinal cord injury and CSF leakeage. METHODS: TARP system with a novel technique of transoral transpedicular screw or articular mass screw of C2 was designed and employed for two patients with irreducible atlantoaxial dislocation, during which one case was with basilar invagination. The histories of the cases and the novel technique of transoral articular mass screw and transpedicular screw insertion of C2 were reported in detail. RESULTS: The two case examples demonstrate the efficacy of this one-stage single transoral approach to the surgical treatment of irreducible anterior atlantoaxial dislocation with spinal cord compression especially in the case of basilar invagination. The role of the TARP in affecting and maintaining the reduction while promoting successful fusion is illustrated. CONCLUSION: The authors' one-stage anterior procedure employing the TARP for the surgical treatment of irreducible anterior atlantoaxial dislocation and basilar invagination was effective in these two cases. This method was able to avoid the need for dens and clivus resection and/or a posterior instrumentation and fusion procedure. The technique of transoral articular mass screw and transpedicular screw insertion of C2 was valuable for transoral atlantoaxial plate internal fixation.

Personalised modified osteotomy using computer-aided design-rapid prototyping to correct thoracic deformities.

The correction of severe thoracic deformities is challenging. However, the usual imaging modalities are not sufficient for performing the surgery. Our objective was to describe the procedure and results of posterior modified wedge osteotomy aided by the techniques of computer-aided design-rapid prototyping (CAD-RP) to correct thoracic deformities. Twenty-one patients with thoracic deformities (eight males; 13 females) formed the study group. All patients underwent computed tomography (CT) scanning and CAD-RP, and a model of thoracic deformities and navigation templates of pedicles were created for each patient and used to analyse the spinal deformities and serve as anatomical reference. Aided by these models, personalised modified wedge osteotomy combining the eggshell technique and posterior vertebral column resection was performed. Using CAD-RP improved the safety and accuracy of surgery and screw placement in the 21 patients in whom 41 vertebrae were removed and 216 pedicle screws were placed. The average operation time was 260 (200-420) min, with an average blood loss of 1,900 ml (range 800-3560 ml). The percentage of deformity correction was 56.3% (from 72.1° to 31.5°) in the coronal plane and 60.4% (from 81.6° to 32.3°) in the sagittal plane. No patient had serious complications or implant failure. Personalised single-stage posterior modified wedge osteotomy is an effective procedure for treating thoracic deformities. Using CAD-RP and the RP models have significant benefits for personalised surgical treatment of complex thoracic deformities.

[Diagnosis and treatment for complicated atlantoaxial dislocation].

OBJECTIVE: To explore the clinical characteristics and treatment methods for complicated atlantoaxial dislocation. METHODS: A retrospective evaluation was done to summarize and analyze the clinical characteristics and complicated factors of 54 patients with complicated atlantoaxial dislocation who could not to be treated effectively by using conventional therapy in our hospital from February 2005 to October 2008. According to different complicated factors, different treatment methods mainly including transoral atlantoaxial reduction plate-III (TARP-III) operation, decompression procedure with deep grinding guided by computer aided design-rapid prototyping (CAD-RP), screw placement technique with CAD-RP guide plate and extensile approach surgery were performed. RESULTS: The average follow-up period was 24 months. Among 54 cases, 48 cases achieved immediate anatomic reduction completely and 6 cases almost achieved anatomical reduction. All the compressed spinal cords were decompressed sufficiently. The decompression rate was 86.0% and the improvement rate of nerve function was 77.8%. Two cases suffered postoperative intracranial infection. CONCLUSION: Some cases of complicated atlantoaxial dislocation can be effectively treated by using TARP-III operation, decompression procedure with deep grinding guided by CAD-RP, individualized screw placement technique with CAD-RP guide plate and extensile approach surgery.

C2 anatomy and dimensions relative to translaminar screw placement in an Asian population.

STUDY DESIGN: A cadaveric specimen study. OBJECTIVES: To determine the applicability of a modified C2 translaminar screw placement in the general adult population and to provide pertinent clinical data for screw insertion. SUMMARY OF BACKGROUND DATA: C2 intralaminar screw fixation has recently been popularized, but this technique carries a potential drawback that the screw may breakout ventrally into the spinal canal. For this reason, a modified C2 translaminar screw fixation technique was developed to intraoperatively verify screw position and thereby decrease the risk or canal compromise. To our knowledge, there has been not an anatomic study evaluating this modification of the translaminar screw technique. METHODS: The tips of the modified screws were aimed such that they exited the dorsal cortex of the center of the contralateral lateral mass, achieving bicortical fixation. A total of 120 adult C2 vertebrae were evaluated bilaterally for the following: thickness of the cranial, midportion, and caudal edge of C2 lamina; the heights of the spinous process, lamina, and lateral mass; inclination angle of the laminae, screw projection length, and trajectory angle of cranial and caudal C2 translaminar screw. RESULTS: A total of 83.3% specimens had bilateral laminar thicknesses ≥4.0 mm and a spinous process height ≥9.0 mm; 5% had a laminar thickness less than 4.0-mm bilaterally; 9.2% had a laminar thickness less than 4.0 mm on one side; 2.5% had a spinous process height lower than 9.0 mm. CONCLUSION: A large percentages of C2 laminae are of sufficient size to safely accommodate a bicortical 3.5-mm diameter screw. The thickness of the lamina and the height of the spinous process are the 2 limiting factors for safe translaminar screws placement. Using a bicortical technique confirms the position of the screw and thereby helps to decrease the risk of neurologic injury from screw penetration of the inner cortex of the lamina.

[Risk factors for postoperative pulmonary complications following transoral operation for the atlanta-axis disorders].

OBJECTIVE: to evaluate the risk factors for postoperative pulmonary complications following transoral operation for the atlanta-axis disorders. METHODS: total 104 cases were collected from January 2005 to June 2009. Twelve variables among patients with PPCs and without PPCs were analyzed by logistic regression analysis. RESULTS: the incidence of postoperative pulmonary complications following transoral operation for the atlanta-axis disorders was 22.1% (23/104). There was significantly difference in 9 variables between patients with PPCs and without PPCs, and 5 variables as serum albumin < 35 g/L (OR = 15.185, P = 0.003), tracheotomy (OR = 32.254, P = 0.015), Frankle grade (OR = 8.866, P = 0.001), the duration of intubation > 4 d (OR = 7.934, P = 0.002), the duration of surgery > 6 h (OR = 16.889, P = 0.006) were found to be significantly related to the development to postoperative pulmonary complications by multivariate analysis. CONCLUSION: serum albumin < 35 g/L, tracheotomy, Frankle grade, the duration of intubation > 4 d, the duration of surgery > 6 h are the risk factors for postoperative pulmonary complications following transoral operation for the atlanta-axis disorders.

Transoral atlantoaxial reduction plate internal fixation for the treatment of irreducible atlantoaxial dislocation: a 2- to 4-year follow-up.

OBJECTIVE: To evaluate the mid-term outcomes of transoral atlantoaxial reduction plate (TARP) internal fixation for the treatment of irreducible atlantoaxial dislocation. METHODS: From April 2003 to April 2005, 31 patients with irreducible atlantoaxial dislocation were treated with TARP internal fixation. The average age was 37.9 years (range, 15-69 years). The subjective symptoms, objective signs, and neurological function of the patients were assessed. Radiography and magnetic resonance imaging (MRI) were performed and the results analyzed according to the Symon and Lavender clinical standard, Japanese Orthopaedic Association (JOA) score for spinal cord function and imaging standard for spinal cord decompression. RESULTS: Complete or almost complete anatomical reduction was obtained in all 31 patients. No screw-loosening or atlantoaxial redislocation was found in 29 cases. According to the Symon and Lavender clinical standard, 14 cases had recovered completely, 7 to mild, 6 to moderate, and 4 to severe type by final follow-up, compared to the preoperative classifications of 4 as moderate, 15 as severe, and 12 as extra severe type. The outcome for 26 patients was evaluated as excellent and in 5 as adequate. The average postoperative improvement in spinal cord function was 73.3% and of decompression of the cervical cord 92.6%. The only complication was loosening of screws in two cases with senile osteoporosis. One case underwent TARP revision surgery and the other posterior occipitocervical internal fixation. Both of them were eventually cured. CONCLUSION: The TARP operation is a good choice for patients with irreducible atlantoaxial dislocation and has valuable clinical application.