BACKGROUND:Vertebral compression fracture is a common disease in the current orthopedic field.However,the occurrence of re-fracture in neighboring vertebrae after surgery is a problem that cannot be ignored,which has a serious impact on the normal life of patients. OBJECTIVE:The aim of this study is to establish four postoperative models with different recovery heights using computed tomography images.By using finite element analysis,we derived the stresses on the neighboring vertebrae at different recovery heights and further explored the importance of postoperative recovery of the height of the injured vertebrae. METHODS:A finite element model of the thoracolumbar spine(T11-L3)was established and validated,on the basis of which four postoperative finite element models of L1 with different recovery heights of 100%,80%,60%,and 40%were constructed,in which the cement capacity varied with the recovery height.The specific models are as follows:Model 1 was the postoperative model with normal recovery height,and the cement capacity was 8.3 mL.Model 2 was the postoperative model in which 20%of the anterior height of the L1 was removed and the posterior convexity angle became 10.41°,and the cement capacity was 6.9 mL.Model 3 was the postoperative model in which 40%of the anterior height of the L1 was removed and the posterior convexity angle became 20.17°,and the cement capacity was 4.7 mL.Model 4 was a postoperative model with 60%of the L1 anterior height removed and the posterior convexity angle changed to 28.85°,with a cement capacity of 3.6 mL.For evaluation of the postoperative model,we applied a moment of 7 Nm and an axial force of 500 N.The followings were recorded and analyzed:peak stresses in the L2 upper endplate and T12 lower endplate;peak stresses in the L2 and T12 cancellous bone. RESULTS AND CONCLUSION:(1)The highest peak stresses for each condition of the L2 upper endplate,T12 lower endplate,L2 cancellous bone,and T12 cancellous bone occurred in Model 1 and Model 4.In particular,the T12 lower endplate,except for the posterior extension condition,the anterior flexion,left and right lateral bending,and left and right rotation conditions all reached their highest peak stresses in Model 4,with stresses of 50.3,33.1,44.9,34.3,and 31.9 MPa.(2)Based on the peak stresses in the adjacent vertebral endplates and cancellous bone,after excluding Model 1 and Model 4,the minimum peak stresses for most of the conditions appeared in the Model 2,and the minimum peak stresses appeared in the Model 2 in 66.6%of the cases,especially in the upper endplates of the L2 and cancellous bone except for the posterior extension condition,the minimum peak stresses all appeared on the Model 2.(3)Therefore,controlling the recovery height at about 100%and 40%of the original height was a dangerous recovery height,which had a greater impact on the neighboring vertebrae.Controlling the recovery height at about 80%of the original height may be a more ideal choice.With a recovery height of about 80%of the original height,the adjacent vertebrae are subjected to less stress,thus reducing the risk of re-fracture of the adjacent vertebrae in the patient.

Objective:To investigate the surgical methods and clinical effects of free superficial peroneal artery perforator flap in repairing small and medium-sized thermal crush injury wounds in the hand.Methods:A retrospective observational study was conducted. From August 2018 to December 2021, 12 patients (19 wounds) with small and medium-sized thermal crush injury in the hand who met the inclusion criteria were hospitalized in Suzhou Ruihua Orthopaedic Hospital, including 5 males and 7 females, aged from 30 to 54 years. The area of the wound was from 2.5 cm×2.0 cm to 14.0 cm×3.5 cm, and all the wounds were repaired by using free superficial peroneal artery perforator flaps from lower leg on one side (including single flap, multiple flaps, and multiple flaps with one pedicle resected from the same donor site). The area of the flap was from 3.5 cm×3.0 cm to 16.0 cm×4.0 cm. The wound in the donor site was sutured directly. The vascular crisis and survival of the flap were observed after operation. The texture, appearance, color, hyperpigmentation, sensation, and two-point discrimination of the flap repaired area were followed up, as well as the hyperplasia of scar and pain condition in the donor and recipient sites. At the last follow-up, the curative effect of flap repair was evaluated by the comprehensive evaluation scale, and the extension and flexion functions of the reserved digital joint were evaluated by the total active movement systematic evaluation method recommended by American Academy for Surgery of Hand.Results:One flap developed arterial crisis on the first day after operation but survived after timely exploration. The other 18 flaps survived successfully after operation. Follow-up of 4 to 24 months after operation showed good texture and appearance in the flap repaired area; the color of the flap repaired area was similar to that of the normal skin around the recipient site, without pigmentation; the protective sensation was restored in all cases, but there was no two-point discrimination; there was no obvious hypertrophic scarring or pain in the donor or recipient site. At the last follow-up, the curative effect of flap repair was evaluated with 3 flaps being excellent and 16 flaps being good; the extension and flexion functions of the reserved digital joint were also assessed, being excellent in 8 fingers, good in 9 fingers, and fair in 2 fingers.Conclusions:The blood supply of superficial peroneal artery perforator flap is sufficient and reliable, and multiple flaps of this type or multiple flaps with one pedicle can be resected from one donor site. The use of this flap to repair small and medium-sized thermal crush injury wounds in the hand results in minimal damage to the donor area, and good postoperative appearance and texture of the flap.

Objective:To explore the surgical method and clinical effect of harvesting 2 ipsilateral free pedicled perforator flaps from a single donor site of superficial peroneal artery in reconstruction of 2 defects in same or adjacent digits.Methods:From November 2017 to August 2021, 12 patients with 2 defects in same or adjacent digits were treated in the Department of Hand Surgery, Suzhou Ruihua Orthopaedic Hospital with 2 ipsilateral free pedicled perforator flaps from a single donor site of superficial peroneal artery. Among the patients, 1 had the defect in dorsal and palmar of index finger, 1 in thumb and index finger, 6 in index and middle fingers, 3 in middle and ring fingers, and 1 in ring and little fingers. The size of digit defects was 1.5 cm×0.8 cm-6.0 cm×3.5 cm. The size of flaps was 2.0 cm× 1.2 cm-8.0 cm×4.0 cm. All the patients were included in postoperative monthly follow-up to assess the recovery of recipient and donor sites at outpatient service, by telephone or WeChat.Results:All 24 flaps in 12 patients survived without vascular compromise and achieved 100% of survival rate. The follow-up period ranged from 4 to 18 months, with an average of 10 months. Six patients were treated with additional flap thinning and plastic surgery at 4 months after the primary surgery due to slightly bloated flaps. Otherwise, all the flaps in the recipient site had neither pigmentation, obvious hyperplasia nor scar pain. All flaps gained the protective sensations, however the assessment of TPD was not conducted. The flaps were wear-resist and had no ulceration. The texture of the flaps was soft with good elasticity, and the flap did not turn to purple or swelling when in cold. The functional recovery of 23 digits in 12 patients was evaluated according to the total active mobility (TAM) of the digits. It achieved excellent in 3 digits, good in 15 digits, and fair in 5 digits, with an excellent and good rate of 78.26%. A linear scar appeared at the donor site without obvious hyperplasia or scar pain. There were normal sensations around the scar and at the digit-tips. The blood supply to the digit-tips was normal.Conclusion:Harvest of multiple free pedicled perforator flaps from a single donor site of superficial peroneal artery is an effective method in reconstruction of 2 defects in same or adjacent digits at the same time. It has advantages of being a simple surgery procedure by sacrificing only one donor site. It achieves a minimal damage to the donor site and a reliable blood supply of the flap.

Objective:To explore the application value of the method of judging the density of small shadows in the lung area by using CT and CT reference films for pneumoconiosis.Methods:The chest imaging data of 244 employees of a large copper company in Tongling City, Anhui Province who underwent occupational physical examination at Tongling Municipal Hospital in Anhui Province from January 2016 to December 2019 were retrospectively analyzed. Totally 244 cases underwent chest CT scan and chest DR radiography at the same time. The shape and size of the small shadows (the size of the circular and quasi-circular nodules in the lung area were represented by p, q, r, and the size of the irregular small shadows were represented by s, t, u), the overall density, the density of small shadows in each lung area, the large shadows, and the diagnosis stage were observed and compared. The small shadow density of each lung area was judged by the method of judging the small shadow density of CT lung area and the reference film, and other observation indicators were judged according to GBZ70-2015 Diagnosis of Occupational Pneumoconiosis. Results:There was a significant difference between CT and DR in judging s-shaped small shadows and no small shadows ( P<0.05), and there was no statistically significant difference in judging p, q, r, t, and u-shaped small shadows ( P>0.05). CT and DR had medium to high consistency in the judgment of the overall density of small shadows (Kappa=0.692, P=0.001), and the diagnostic coincidence rate was 82.38% (201/244). There was moderate to high agreement between CT and DR in the density of small shadows shown in the right upper, right lower, left upper, left middle, and left lower lung regions (Kappa ranged from 0.40 to 0.75, P<0.05), and the consistency in the right middle lung region was poor (Kappa=0.381, P=0.001). Eleven large shadows were detected in 8 cases by DR, 31 large shadows were detected in 23 cases by CT, and 20 (8.20%) large shadows were detected more frequently by CT than DR. The agreement between CT and DR for the diagnosis and staging of silicosis was excellent (Kappa=0.843, P=0.001), and the diagnostic coincidence rate was 91.80% (224/244). Conclusion:Applying the method of determining the density of small shadows in the lung area of pneumoconiosis and reference films, combined with GBZ70-2015 Diagnosis of Occupational Pneumoconiosis, can make a more accurate diagnosis of silicosis.

BACKGROUND:The elastic modulus of traditional bone implants is large and does not match the elastic modulus of human bone,which will cause a stress shielding effect and lead to bone resorption.The trabecular scaffold of the triply periodic minimal surface with radial gradient has elastic modulus matching with human cancellous bone,and its yield strength is greater than that of human cortical bone,which provides a new choice for the design of bone scaffold. OBJECTIVE:Triply periodic minimal surface structure with radial gradient was constructed by the implicit surface method.The sample was manufactured by laser selective melting technology,and the quasi-static compression test was carried out to obtain trabecular scaffolds with mechanical properties matching human bones. METHODS:Four types of the trabecular scaffolds of the triply periodic minimal surface with a radial gradient of G,I,P and D were established by the implicit surface method.Samples were manufactured by laser selective melting technology.We observed the surface morphology of the molded sample,evaluated the molding quality,conducted a quasi-static compression test,and evaluated the mechanical properties of the samples. RESULTS AND CONCLUSION:The quasi-static compression test results showed that compared with the four triply periodic minimal surface scaffolds,the platform stress of the G scaffold had less fluctuation and no failure or fracture,indicating that the G scaffold had the best plasticity.The mechanical properties of the G scaffolds with 45%,55%and 65%porosities were analyzed.It was found that the elastic modulus of G scaffolds with 55%porosity was within the range of elastic modulus of human cancellous bone(0.022-3.7 GPa),and the yield strength was close to the maximum yield strength of human cortical bone(187.7-222.3 MPa).In conclusion,G triply periodic minimal surface scaffold with 55%porosity can reduce the stress shielding effect,bear a higher body load,improve the stability of the implant,and prolong the service life of the implant.

Objective:To summarise the clinical application and results of superficial peroneal artery perforator flaps in tiled reconstruction of thumbs and fingers.Methods:From June 2020 to June 2022, 8 patients with finger or thumb defects (4 thumbs, 2 index fingers and 2 middle fingers) received digit reconstruction in the Department of Hand Surgery, Suzhou Ruihua Orthopaedic Hospital. Two thumbs (2 patients) were reconstructed with a free partial hallux nail flap combined with a free perforator flap of superficial peroneal artery and an iliac bone graft, 1 thumb was reconstructed with a free partial hallux nail flap combined with a free perforator flap of superficial peroneal artery, 1 thumb and 2 middle fingers were reconstructed with free perforator flaps of superficial peroneal artery combined with iliac bone grafts, and 2 index fingers were reconstructed with lobulated free perforator flaps of superficial peroneal artery. The sizes of the flaps were 1.8 cm×3.2 cm-4.0 cm×10.0 cm. Lengths of iliac crest were 1.5-4.0 cm. The donor sites were directly sutured in 5 patients, skin grafts in 2 and superficial peroneal artery perforator flap reconstruction in 1 patient. Postoperative observations included survival of the digits and healing of the bone grafts. Monthly scheduled postoperative follow-ups were conducted at outpatient clinics and via telephone or WeChat reviews, covering function and appearance of the reconstructed digits, impact on the function and appearance of donor sites as well as the satisfaction of patients.Results:All 8 reconstructed digits survived in one stage and all the 5 bone grafts healed at 3 to 4 months after surgery. The mean postoperative follow-up period was 10 months, ranged 4 to 20 months. The texture of the reconstructed digits was close to that of the recipient site and good in elasticity, without purplish while in cold, nor ulceration, obvious bloating and pigmentation. Sensation of the digit pulps was recovered to S 2 to S 3, and the sensation in touch, pain and temperature were restored. TPD was not checked. There was no noticeable hyperplasia nor pain in the recipient and donor sites. There was no obvious hyperplasia or pain at the donor sites for the hallux nail flap, and the skin grafts or flaps in the donor sites survived well without ulceration or pain and the function of the donor feet were not affected. Functions of the reconstructed digits were assessed according to the Functional Assessment Criteria for Thumb and Finger Reconstruction of the Society for Evaluation Standard of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, 4 patients achieved in excellent and 4 in good. According to the University of Michigan Hand Profile Questionnaire (MHQ), patient satisfaction was found very satisfied with 4 patients and satisfied with the other 4 patients. Conclusion:The superficial peroneal artery perforator flap has advantages of thin and large area with pleasant texture, better sensation recovery and less damage to the donor site. It is an ideal flap for reconstruction of thumbs and fingers.

This study aims to propose a multifrequency time-difference algorithm using spectral constraints. Based on the knowledge of tissue spectrum in the imaging domain, the fraction model was used in conjunction with the finite element method (FEM) to approximate a conductivity distribution. Then a frequency independent parameter (volume or area fraction change) was reconstructed which made it possible to simultaneously employ multifrequency time-difference boundary voltage data and then reduce the degrees of freedom of the reconstruction problem. Furthermore, this will alleviate the illness of the EIT inverse problem and lead to a better reconstruction result. The numerical validation results suggested that the proposed time-difference fraction reconstruction algorithm behaved better than traditional damped least squares algorithm (DLS) especially in the noise suppression capability. Moreover, under the condition of low signal-to-noise ratio, the proposed algorithm had a more obvious advantage in reconstructions of targets shape and position. This algorithm provides an efficient way to simultaneously utilize multifrequency measurement data for time-difference EIT, and leads to a more accurate reconstruction result. It may show us a new direction for the development of time-difference EIT algorithms in the case that the tissue spectrums are known.