Risk Factors for Postoperative Surgical Site Infection in Patients Undergoing Spinal Tumor Surgery.

STUDY DESIGN: A retrospective comparative case-control study. OBJECTIVE: The aim of this study was to determine the risk factors for postoperative surgical site infection (SSI) in patients with spinal tumors requiring reoperation during the perioperative period. SUMMARY OF BACKGROUND DATA: SSI is a common postoperative complication of spinal surgery. The occurrence of SSI not only increases the mortality rate but prolongs the patient's hospital stay and increases the medical cost. METHODS: Included in this study were 202 patients with spinal tumors who received surgical treatment between January 2008 and December 2018, of whom 101 patients who developed SSI and underwent secondary surgery were used as the SSI group, and the other 101 patients with no SSI who were matched with the SSI group by age (±10), pathologic diagnosis (malignant/no-malignant), tumor site (C/T/L/S), surgical approach (anterior/posterior/combined), and surgical team were used as the control group. The clinical data of the 202 patients in both groups were analyzed by logistic regression modeling to identify SSI-associated risk factors. RESULTS: Multivariate logistic regression analysis showed that the revision status ( B =1.430, P =0.028), the number of spinal levels fused ≥4 ( B =0.963, P =0.006), and the use of bone cement ( B =0.739, P =0.046) were significantly associated with the increased risk of developing postoperative SSI. CONCLUSIONS: This study identified the revision status, the number of spinal levels fused ≥4, and the use of bone cement as independent risk factors for SSI in patients with spinal tumors who underwent reoperation during the perioperative period.

A Spray-Filming Self-Healing Hydrogel Fabricated from Modified Sodium Alginate and Gelatin as a Bacterial Barrier.

Self-healing hydrogels as wound dressings still face challenges in infection prevention, especially in the dressing of mass wounds, due to their inflexibility and the slow formation of the protective film on the wound. Therefore, designing a spray-filming (rapid-forming) hydrogel that can serve as a bacterial barrier is of particular significance in the development of wound dressings. Here, a self-healing hydrogel based on adipic acid dihydrazide-modified gelatin (Gel-ADH) and monoaldehyde-modified sodium alginate(SA-mCHO) is prepared. Using dynamic, Schiff base bonds, the hydrogels exhibit excellent self-healing properties. Moreover, the gelation time of SA-mCHO/Gel-ADH (SG) hydrogels is shortened to 2-21 s, resulting in rapid filming by spraying the two precursor solutions. In addition, the rapid spray-filming ability might offer sufficient flexibility and rapidity for dealing with mass and irregular wounds. Notably, the bacterial barrier experiments show that the SG hydrogel films could form an effective barrier to Staphylococcus aureus and Candida albicans for 12 h. Therefore, SG hydrogels could be used in wound dressings and they show great promise in applications associated with mass and irregular traumas.

Biomechanical analysis of a novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body: a finite element study.

BACKGROUND: To compare the biomechanical properties of a novel height-adjustable nano-hydroxyapatite/polyamide-66 vertebral body (HAVB) with the titanium mesh cage (TMC) and artificial vertebral body (AVB), and evaluate its biomechanical efficacy in spinal stability reconstruction. METHODS: A 3D nonliner FE model of the intact L1-sacrum was established and validated. Three FE models which instrumented HAVB, TMC, and AVB were constructed for surgical simulation. A pure moment of 7.5 Nm and a 400-N preload were applied to the three FE models in 3D motion. The peak von Mises stress upon each prosthesis and the interfaced endplate was recorded for analysis. In addition, the overall and intersegmental range of motion (ROM) of each model was investigated to assess the efficacy of each model in spinal stability reconstruction. RESULTS: AVB had the greatest stress concentration compared with TMC and HAVB in all motions (25.6-101.8 times of HAVB, 0.8-8.1 times of TMC). The peak stress on HAVB was 3.1-10.3% of TMC and 1.6-3.9% of AVB. The maximum stress values on L2 caudal and L4 cranial endplates are different between the three FE models: 0.9-1.9, 1.3-12.1, and 31.3-117.9 times of the intact model on L2 caudal endplates and 0.9-3.5, 7.2-31.5, and 10.3-56.4 times of the intact model on L4 cranial endplates in HAVB, TMC, and AVB, respectively, while the overall and segmental ROM reduction was similar between the three models, with AVB providing a relatively higher ROM reduction in all loading conditions (88.1-84.7% of intact model for overall ROM and 69.5-82.1% for L1/2, 87.0-91.7% for L2/4, and 71.1-87.2% for L4/5, respectively). CONCLUSIONS: HAVB had similar biomechanical efficacy in spinal stability reconstruction as compared with TMC and AVB. The material used and the anatomic design of HAVB can help avoid stress concentration and the stress shielding effect, thus greatly reducing the implant-associated complications. HAVB exhibited some advantageous biomechanical properties over TMC and AVB and may prove to be a potentially viable option for spinal stability reconstruction. Further in vivo and vitro studies are still required to validate our findings and conclusions.

A Novel Height-Adjustable Nano-Hydroxyapatite/Polyamide-66 Vertebral Body for Reconstruction of Thoracolumbar Structural Stability After Spinal Tumor Resection.

BACKGROUND: Reconstruction of thoracolumbar structural stability is a formidable challenge for spine surgeons after vertebral body tumor resection. Various disadvantages of the currently used expandable or nonexpandable cages have limited their clinical applications. We sought to develop a novel prosthesis for clinical use and assess its preliminary clinical outcome in reconstruction of thoracolumbar structural stability after spinal tumor resection. METHODS: Using data obtained from a retrospective analysis of the morphological characteristics of the thoracolumbar vertebrae and endplates in previously reported studies, we modified the nano-hydroxyapatite/polyamide-66 (n-HA/PA66) strut into a novel height-adjustable vertebral body. A retrospective study was performed of 7 patients who had undergone reconstruction of thoracolumbar structural stability with this novel prosthesis from August 2016 to January 2017. RESULTS: A novel height-adjustable vertebral body (AHVB) composed of n-HA/PA66 with 2 separate components with a 163° contact surface at each end was manufactured. The height-adjustable range was 28-37 mm. No significant implant-related complications were observed in the process of operation. All patients experienced a significant reduction in pain, with the visual analog scale score decreasing from 7.9 to 4.0. Neurological improvement was assessed using the Frankel grading system after surgery. Postoperative radiographic and computed tomography/magnetic resonance imaging findings indicated that the operated segment was stable, the outcome of kyphosis correction was good, and no prosthesis subsidence or dislocation was observed. CONCLUSION: This novel prosthesis has many advantages in the reconstruction of height, lordosis, and alignment after thoracolumbar spinal tumor resection and has a favorable prospect for clinical application.

[Clinical characteristics and diagnosis of rheumatoid arthritis of upper cervical spine: analysis of 71 cases].

OBJECTIVE: To study the clinical characteristics and diagnosis of rheumatoid arthritis (RA) in the upper cervical spine. METHODS: The clinical data of 71 patients with RA in the upper cervical spine, 18 males and 53 females, aged 46.2 (23-76), with a mean duration of RA of 18.2 years (2 months-47 years) were retrospectively reviewed. Fifty-three patients received glucocorticoid for more than 3 months. In addition to routine examinations, all patients underwent plain X-ray film taking, CT and MRI scanning, and erythrocyte sedimentation rate, rheumatoid factor (RF) and antistreptolysin O testing. RESULTS: The symptoms of upper cervical spine appeared at 8.3 years (2 months-46 years) after the diagnosis of RA was confirmed. The clinical manifestations of RA in the upper cervical spine were intractable pain in craniocervical junction or radiating pain. Abnormal postures in the neck and Sherp-Purser's sign were positive in some patients. Progressive neurological dysfunction with the involvement of spinal cord, medulla, or some cranial nerves might gradually appear. Irregular destruction of bone with osteoporosis around the lateral and median atlantoaxial joint was a common finding in the X-ray films and CT scans. Instability of the atlantoaxial joint, including anterior atlantoaxial subluxation, posterior atlantoaxial subluxation and anterior-posterior atlantoaxial subluxation were found in 68 cases, while rotation subluxation was presented in 37 cases. Vertical migration of the odontoid was seen in 11 cases. RF was positive in 18 cases. MRI revealed that the cause of spinal cord compression was the bone tissue and soft tissue pannus. CONCLUSIONS: RA in the upper cervical spine is a common situation in the clinical settings. The key point in the diagnosis of this disease is the identification of instability in the atlantoaxial joint and assessment of the spinal neurological deficit. And a careful analysis of the natural history will further help to achieve a better treatment effect.

[Biomechanical performance of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability].

OBJECTIVE: To compare the biomechanical performances of different wires and cable fixation devices in posterior instrumentation for atlantoaxial instability, and test the effect of different fixation strengths and fixation approaches on the surgical outcomes. METHODS: Six specimens of the atlantoaxial complex (C0-C3) were used to establish models of the normal complex, unstable complex (type II odontoid fracture) and fixed complex. On the wd-5 mechanical testing machine, the parameters including the strength and rigidity of anti-rotation, change and strength of stress, and stability were measured for the normal complex, atlantoaxial instability complex, the new type titanium cable fixation system, Atlas titanium cable, Songer titanium cable, and stainless wire. RESULTS: The strength and rigidity of anti-rotation, change and strength of stress, stability of flexion, extension and lateral bending of the unstable atlantoaxial complex fixed by the new double locking titanium cable fixation system were superior to those of the Songer or Atlas titanium cable (P<0.05) and medical stainless wire (P<0.05). Simultaneous cable fastening on both sides resulted in better fixation effect than successive cable fastening (P<0.05). Better fixation effect was achieved by fastening the specimen following a rest (P<0.05). CONCLUSIONS: The fixation effects can be enhanced by increased fastening strengths. The new type double locking titanium cable fixation system has better biomechanical performance than the conventional Songer and Atlas titanium cables. Fastening the unstable specimens after a rest following simultaneous fastening of the specimen on both sides produces better fixation effect.

[Anti-rotation biomechanical study of wire and various cable system in the posterior brooks instrumentation for atlantoaxial instability].

OBJECTIVE: To compare the anti-rotation biomechanical performances of wire and various cable fixation devices currently used in the posterior Brooks instrumentation for atlantoaxial instability. METHODS: In this experiment,six specimens of the atlantoaxial complex (Occipital-C3) were used. The models of the normal complex,unstable complex (type II odontoid fracture) and fixed complex were established. On the WD-5 mechanics experimental machine,the parameters including the strength and rigidity of anti-rotation were quantified for the normal complex (group N),the atlantoaxial instability complex (group M), the new type Titanium cable (group A), Atlas titanium cable (group B), Songer Titanium cable (group C), stainless wire(group D). RESULTS: The max strength of A, B, C, D groups was 12.5, 11.3, 11.52, 11.55 N x m respectively, the max rigidity was 58.81, 53.17, 54.11, 54.35 N x cm/deg respectively. The strength and rigidity of anti-rotation, compare to the unstable atlantoaxial complex which were fixed by the new double locking Titanium cable fixation system were superior to those of normal complex, instability complex, Songer or Atlas Titanium cable (P < 0.05). CONCLUSION: Having been changed the locking method, the anti-rotation biomechanical characteristics of the new type double locking Titanium cable fixation system are superior or similar to the traditional Songer or Atlas Titanium cable.