Simple Fixation Research Articles

An Experimental Study on the Effect of Visual Tasks on Discomfort Due to Peripheral Glare

ABSTRACTThis article concerns discomfort due to sources of glare in the peripheral visual field. A visual task is needed to maintain foveal fixation at a known location, and in past studies the tasks have ranged from a simple fixation mark to a task requiring greater cognitive attention such as reading. It was hypothesized that these different approaches to control visual attention would influence the evaluation of discomfort. This article reports an experiment that compared evaluations of discomfort when using the two visual tasks, a simple circle and a pseudo-text reading task, and two procedures, category rating and luminance adjustment. The results from both procedures confirmed the hypothesis: a lower degree of discomfort was expressed in the pseudo-text trials than in trials with the circular fixation mark.

Clinical analysis of pedicle screw fixation in the treatment of type II odontoid fracture with bone grafting and non-bone grafting

Objective To explore the clinical efficacy of bone grafting in the treatment of type Ⅱ odontoid fracture with pedicle screw fixation. Methods Of 14 cases with type Ⅱ odontoid fractures, 8 patients in group A received pedicle screw, lamina autologous bone grafts, 6 cases of group B received simple posterior pedicle screw fixation.The operative time, the amount of surgical bleeding and the postoperative cervical spine flexion and rotation were observed at 3 months postoperatively, and the patients were followed up for 5-45 months. Results All patients were followed up for 5-45 months, with an average of 26.5 months.The operation time was (1.83±0.5)h in the bone graft group, and (1.58±0.9)h in the non-bone graft group, the difference was statistically significant (t=2.842, P>0.05). The blood loss of the bone graft group was (150±16)mL, which of the non-bone graft group was (120±14)mL, the difference between the two groups was statistically significant (t=3.57, P>0.05). After 3 months, the flexion of the cervical spine of the bone graft group was (31.2±4.6)°, which in the non-grafted group was (32.3±5.7)°, the difference was statistically significant (t=0.675, P<0.05). The rotation of the bone graft group was (40.6±4.5)°, which in the non-graft group was (41.3±3.5)°, the difference was statistically significant (t=0.278, P<0.05). Both two groups had no vertebral artery and spinal cord injury, wound healing.During the follow-up period, the two groups of patients had a good reduction of cervical spine, no internal fixation lossening, fracture, fracture healing well, group A bone graft fusion. Conclusion For this type of fracture, simple atlantoaxial pedicle screw fixation compared with autologous iliac bone graft fusion treatment, can save the operation time, reduce the amount of bleeding. Key words: Fracture, bone; Pedicle screw; Cervical vertebrae

A new mandibular anchorage solution inspired from alpinism

In this article, we are presenting a new mandibular anchorage solution through three clinical cases. This method is based on a mountain climbing technique. Thanks to a simple fixation wire insert in the jaw bone, it is now possible to obtain a backward movement of the mandibular arch and a significant uprighting of the incisors.

A Novel Vesicoscopic Bladder Wall Suture Fixation Technique to Aid Endoscopic Vesicostomy Button Insertion

Background: To describe a novel bladder fixation technique for use during endoscopic vesicostomy button insertion. Methods: After standard cystoscopic visualization of the bladder, a standard 18 G intravenous cannula was inserted into the bladder. A non-absorbable suture thread was placed through this intravenous cannula under cystoscopic vision. The proximal end of the suture was then removed using standard ureteroscopic grasping forceps (3 Fr) through another needle (15 G) inserted next to the initial puncture site (following a path at 30 degrees from the initial puncture tract) into the bladder. The suture ends were brought out of the bladder and tied at the skin level, 2 cm from the intended vesicostomy site. Sutures were removed on the second postoperative day. Results: This fixation technique allows for adequate fixation of the bladder dome to the anterior abdominal wall. These sutures also have less potential for cutaneous scarring and pain. No complications were reported. Conclusion: This simple fixation technique is easily performed using materials found in every urology suite. It also avoids the skills required with other previously reported fixation suture techniques, and can also be utilized for bladder fixation in cases of vesicoscopic laparoscopic or robotic assisted laparoscopic procedures.

Is it necessary to plate all posterior wall fractures of the acetabulum?

Background Posterior wall injuries represent the commonest type of acetabular fractures. It could be isolated fractures or − more commonly − associated with hip dislocation with varying degrees of displacement and comminution. Being intra-articular injuries affecting the congruency and stability of the hip joint, 30% of patients with such injuries have poor outcomes. Accurate fracture reduction with stable fixation is the standard way for achieving satisfactory results. This study aims to evaluate the suitability and efficacy − in light of the clinical and radiological results − of using only screws for fixation of certain posterior wall fractures through a limited exposure using the Kocher-Langenbeck approach. Patients and methods This study included 16 cases of displaced posterior wall fractures with single, sizable fragment or multiple, noncomminuted fragments treated with open reduction and internal fixation using only screws through a limited exposure using the Kocher-Langenbeck approach. In 14 cases, fractures were associated with hip dislocation whereas the last 2 cases had isolated posterior wall injuries. Radiological assessment according to Matta and Heeg criteria and clinical evaluation according to Postel score were done postoperatively and throughout the follow-up period that extended for a mean duration of 18.9±6.7 months. Results Clinically satisfactory results (excellent and good) were reported in 14 cases, representing 87.5% of the studied cases. One case was rated fair and one case was rated poor, so unsatisfactory results (fair and poor) were reported in two cases, representing 12.5% of the studied cases. According to the modified criteria of Matta, 12 cases had excellent reduction and four cases had good reduction, and according to the radiographic grading criteria by Heeg, 14 cases were excellent with a normal-appearing hip joint compared with the healthy side; one case was fair with joint narrowing less than 50% compared with the other healthy side with no osteophytes and viable head; and one case was rated as poor with advanced degenerative changes, head subluxation, and severe avascular necrosis. No cases developed heterotopic ossification or implant failure. Conclusion Fixation by only screws through a limited exposure could be a simple and reliable fixation method for certain posterior wall fractures with less soft tissue dissection and intraoperative and postoperative complications, with comparable clinical and radiological results to the more complex fixation methods using conventional reconstruction plates or locked plates.

Insight into the pathogenesis of Autologous Platelet Plasma (APP): The regenerative and therapeutic benefits as a treatment of acute injuries, tendinopathy and fasciopathy, pain and osteoarthitis as well as chronic inflammations (acne, psoriasis)

Introduction: Several options continue to evolve for treating the common olecranon fractures. The reported high percentage of skin and implant related complications for these subcutaneous fractures raised the question about the need for a miniinvasive line of treatment that improves the results and minimizes the complications. Objectives: Prospective evaluation of the new line of treatment, crossing screws, versus the standard technique, Tension Band Wiring (TBW) in treatment of isolated non-comminuted olecranon fractures. Methods: A prospective study of 22 patients with Mayo type IIA olecranon fractures was conducted to evaluate the 2 techniques. They were divided into 2 groups: Group 1 included 11 patients treated by crossing screws and group 2 included 11 patients that were treated by TBW. Compression by the transcortical partially threaded screws applied in a crossing manner offers a stable fixation without soft tissue compromise that allows faster fracture healing and carry no danger for the skin. The patients were evaluated for operation time, quality of reduction, fracture healing, implant position, elbow range of motion, stability of fixation, and presence of complications. The functional evaluation was based on the Mayo Elbow Performance Score (MEPS). Results: All the fractures united in both groups in accepted position except one in group 2. No secondary procedure to achieve union was required only in that case. No fixation failure or implant migration problems were encountered in group 1, but, 2 cases in group 2. Faster radiographic union was encountered in group 1. One case in group 1 versus 2 in group 2 got superficial infection. No vascular or nerve complications were found. At a mean follow-up of 12.6 months (range 12-18 months), the elbow Range of Motion (ROM) and forearm rotation in group 1 were comparable to the intact side except 5 degrees extension deficit in 2 patients versus 2 patients with extension deficit 10 degrees and 2 patients with 5 degrees extension deficit. Using the MEPS, group 1 patients (100%) had a good to excellent results with a mean score of 94.3 (80-100), one patient had implant removal. In group 2, the mean score was 91.6 (75-95), with 6 cases had implant removal. Conclusion: Percutaneous or mini-open transcortical crossing screws for isolated non-comminuted olecranon fractures offered a cheap, simple and efficient mini-invasive stable fixation that allows early rehabilitation with excellent results and minimal complications. Their results were superior to the standard TBW. A multicenter comparative study is recommended before standardization of the technique

Application of vacuum pad and body film fixation in radiotherapy for thoracic and abdominal tumors

Objective To investigate the clinical value of vacuum pad and body film fixation in radiotherapy for thoracic and abdominal tumors. Methods A total of 240 patients with thoracic and abdominal tumors who were treated with radiotherapy were randomly selected and divided into group A (simple vacuum pad fixation, 60 patients), group B (simple body film fixation with unimproved solid plate, 60 patients), and group C (vacuum pad and body film fixation with improved solid plate, 120 patients). The difference between groups were analyzed with single variance analysis method. Results The setup error was small in group C and large in groups A and B. There were significant differences in the setup error between the three fixation methods (P=0.000). Conclusions A combination of vacuum pad and body film fixation is better than vacuum pad or body film fixation in radiotherapy for thoracic and abdominal tumors. The combination method has many benefits, including simple and convenient operation, comfortable and repeatable body fixation, reduced artificial errors, and improved positioning precision. Key words: Thoracic and abdominal neoplasmsm/radiotherapy; Vacuum mat+ body film fixation; Set-up error

Treatment of dorsal fracture-dislocation of the proximal interphalangeal joint using the Ligamentotaxor device: clinical and radiographic preliminary results.

Fracture-dislocations of the proximal interphalangeal joint are complex injuries, often difficult to treat. Several treatment options have been described. Among them dynamic external fixation proved to be a safe technique leading to good results in many authors experience. The principles of this treatment are to avoid edema, prevent stiffness and tendon adhesions, promote joint remodelling and facilitate rehabilitation. The Ligamentotaxor® device is a simple and reproducible dynamic external fixation system that has been used in recent years to treat proximal interphalangeal joint fracture-dislocations, with favourable results. The aim of the present study is to evaluate our preliminary results with the Ligamentotaxor® device for treatment of these complex lesions. Four patients between December 2015 and January 2017 were treated at our institution with the Ligamentotaxor® device. Clinical and radiographic results were evaluated at mean 6 months follow-up. Clinical results were meanly good and appeared to be comparable to most recent literature. Mean range of motion was 60,5°, mean extension lag 18,5°. Mean QuickDASH and Michigan Hand Questionnaire scored 21.6 and 72 respectively. Radiographic evaluation showed fracture healing in all cases. No relevant complications were noted. The Ligamentotaxor® device is simple to implant, provides good stability and allows an immediate gentle active movement. According to present work the preliminary results are encouraging.

Surgical management in treating periprosthetic femoral fractures after hip arthroplasty

Objective To observe the clinical outcomes of the surgical management of periprosthetic femoral fractures following hip arthroplasty. Methods Twelve consecutive patients (6 male and 6 female) with the average age of 66.4±15.0 years old (35 to 86 years old) undergoing surgical operation for periprosthetic femoral fractures between September 2009 and May 2016 were followed up at our center. Nine cases were fractured secondary to the primary hip arthroplasty while the others were patients with earlier revision surgery. The previous fixations of femoral components of 10 cases were cementless while the other two were cemented fixation. The enrolled patients were determined as Vancouver type B1 (n=2), type B2 (n=7), type B3 (n=1) and type C (n=2) respectively. The occurrences of the fractures were observed at 3 weeks to 17 years post-operation (average 9.0±7.0 years). The patients were treated individually according to different Vancouver types. Type B1 patients received simple cerclage fixation, as well as revisions with long-stem femoral implants and cerclage band were chosen for type B2 patients. In addition to the treatment for type B2 patients, allogenic cortical bone graft was also required for type B3 patients. Open reduction with locking plate internal fixations were options for patients with Vancouver type C fractures. The following-up included the X-ray images of the hips, Harris hip score and the visual analogue scale (VAS) for the pain of fracture site. The unions of the fractures were determined by both X-ray images and pain intensity of the fracture sites. Results The mean follow-up period was 41.6±26.0 months (range, 12-92 months), without patient lost to follow up. VAS scores were 0, implying the clinical union of the fractures. One patients received multiple debridement post-operatively due to the periprosthetic infection. The VAS score of this patient was 6 at the follow up and the X-ray image indicated the nonunion of the fracture. The fracture union rate was 91.7% (11/12). The Harris hip score was 23-92 (mean score, 74.8±18.8), excellent for 2 cases, good for 6 cases, fair for 3 cases and poor for 1 case. The excellent and good rate was 66.7% (8/12). Post-operative complications were observed in 4 patients (33.3%, 4/12). One drainage tube was misplaced and sutured subcutaneously required a further exploration surgery. One periprosthetic infection occurring post-operatively induced the nonunion of the fracture. Aseptic loosing of femoral stem was observed in 2 cases and subsequent revision surgeries were conducted. Conclusion High incidence of complications is observed after the surgical treatment of periprosthetic femoral fractures following hip arthroplasty. Individually customized management regarding to the Vancouver type of periprosthetic femoral fractures leads to the clinical fracture union in 91.7% of the patients in this case series. The excellent and good rate of the hip function in the early and mid-term stage after operation is 66.7%. Key words: Femur; Periprosthetic fractures; Arthroplasty, replacement, hip; Fracture fixation, internal

Transfixing Kirshner wires for fixation of intertrochanteric valgus osteotomies in management of pediatric coxa vara

BackgroundCoxa vara is a radiological term describing a decrease in the neck–shaft angle to 120° or less. Coxa vara is associated with pathomechanical changes that can manifest clinically. If left untreated, coxa vara can affect the normal development of the pediatric hip. Valgus osteotomy is the standard surgical treatment for coxa vara, but there is no consensus regarding the optimal osteotomy technique and fixation method. The work reported here aimed to highlight transfixing wires as a fixation method for valgus osteotomy applied as treatment for various types of pediatric coxa vara.Materials and methodsThis study included 16 cases of pediatric coxa vara with different etiologies in 9 patients with a mean age of 39.9 ± 15.2 months. Radiological and clinical evaluations and scoring of the condition of each patient according to the Iowa Hip Score were performed pre- and postoperatively. Transfixing wires and a protective spica were used for the fixation of a V-shaped, laterally based, closing-wedge valgus osteotomy in all cases. The postoperative follow-up period ranged from 14 to 102 months, with a mean duration of 33.3 ± 27.7 months.ResultsThe mean Hilgenreiner epiphyseal angle (HEA) was corrected from 81.7 ± 2.2° to 24.3 ± 3.5° and the mean femoral neck–shaft angle (FNSA) was improved from 86.9 ± 4.2° to 138.6 ± 3.5°. No recurrence of the deformity was observed during the follow-up periods considered here. The osteotomy site united after an average of 11.7 ± 2.2 weeks with no secondary displacement, and in cases of developmental coxa vara there was progressive ossification of the neck defect with no surgery-related complications. Clinical results were markedly improved by the osteotomy, with a mean postoperative Iowa Hip Score at last follow-up of 95.06 ± 2.6, compared to a mean preoperative score of 57.4 ± 3.6.ConclusionsTransfixing wires protected in a hip spica cast represent a simple, easy, and reliable fixation method for valgus osteotomies performed to correct pediatic coxa vara. It assures stable fixation and rapid healing of the osteotomy without loss of the achieved correction, it completely avoids the femoral neck affording marked protection to the growth plate.Level of evidenceIV.

Robot-assisted surgery guided by damage control orthopaedics for pelvic fractures in polytrauma patients: preliminary results of 26 patients

Objective To evaluate the safety and efficiency of robot assisted surgery guided by damage control orthopaedics(DCO) in polytraumatised patients with pelvic ring injuries. Methods A retrospective review of the pelvic fracture database was performed. Twenty-six patients who had sustained a pelvic fracture from September 2012 to December 2015 were suitable for robot-assisted minimally invasive internal fixation. They were 17 men and 9 women, aged from 23 to 58 years (average, 42.6 years). Their Injury Severity Score(ISS) ranged from 20 to 31 points (average, 21.3 years). According to Tile classification, 6 cases were type B2, 3 type B3, 9 type C2 and 8 type C3. Guided by DCO, the vital signs were stabilized by all means and the fractures treated by simple and temporary external fixation before the pelvic and other fractures were managed by the robot-assisted minimally invasive internal fixation. Demographics, times to operating room (TOR), time from acute stabilization to late definitive internal fixation (TAL), time for bone union, type of robot-assisted surgery for major fractures, length of stay (LOS), postoperative complications and mortality were recorded. The outcomes of the pelvis were evaluated at the final follow-up according to the Matta criteria. Results Of the 26 patients, robot-navigated percutaneous screwing was conducted with 23 sacroiliac screws in 19, with 9 ramus pubicus screws in 9, with 6 supraacetabular screws in 4, and with 4 both-column screws in 2 cases. TOR averaged 2.7 times, TAL 5.9 days, LOS at ICU 2.1 days, ICU ad-mission rate 46.2% (12 of 26), hospital LOS 7.3 days, and time for pelvic bone union 79.0 days. None patients had postoperative complications related to the pelvic fracture and no one died. According to the Matta criteria at the final follow-ups, 8 cases were excellent, 11 good, 5 fair and 2 poor, yielding an excellent and good rate of 73.1%. Conclusion Robot-navigated minimally invasive surgery plus DCO is effective, time saving and safe treatment for polytraumatised patients with pelvic ring injuries. Key words: Pelvis; Fractures, bone; Robotics; Surgical procedures, minimally invasive

The Effect of Fixation Technique on Continuous Interscalene Nerve Block Catheter Success: A Randomized, Double-Blind Trial.

Continuous peripheral nerve blocks offer advantages over single-injection blocks, including extended analgesia and reduction in opioid consumption. These benefits require that the perineural catheter remain intact for the duration of the planned local anesthetic infusion. Mechanical displacement of catheters, leaking, and consequent failure are known complications. The aim of this study was to evaluate continuous perineural catheter tip-to-nerve apposition in vivo over 48 hours comparing 2 different simple fixation strategies. Subjects presenting for a continuous interscalene nerve block were randomized to perineural catheter fixation with 1 of 2 types of adhesive: Dermabond (2-octylcyanoacrylate) or Mastisol (alcohol 23A, gum mastic, storax, and methyl salicylate), covered with a simple transparent dressing. The primary outcome was the evaluation of catheter-to-nerve apposition maintenance over 48 hours via both a blinded ultrasound evaluation of local anesthetic distribution and a blinded clinical assessment. Secondary outcomes included leakage at the catheter site, pain scores, opioid consumption, catheter-to-skin migration at the insertion site, and patient satisfaction. Sixty-six subjects were recruited and randomized to compare adhesive group catheter tip-to-nerve apposition on postoperative day 2 (POD 2). Within the intention-to-treat cohort, a statistically significant decrease of perineural catheter tip-to-nerve apposition in the Mastisol group (64.7%) compared with the Dermabond group (90.6%) on POD 2 (odds ratios [OR] 0.19; 95% confidence interval [CI] 0.05-0.75; P = .012) was observed. Similar results were observed on POD 1 (OR 0.19; 95% CI 0.03-1.38; P = NS) and POD 2 (OR 0.14; 95% CI 0.02-0.97; P = .008) within the as-treated cohort. Catheter leakage (OR 67; 95% CI 7.3-589) and median catheter migration difference at the skin insertion site (2.0 cm; 95% CI 0.5-2.5) were also significantly greater in the Mastisol group than in the Dermabond group from POD 0 to POD 2 (P < .001). Median postoperative opioid consumption difference in morphine equivalents (3.2 mg; 95% CI - 9.0 to 14.2) was not significantly different between the Dermabond and the Mastisol groups through POD 2 (P = .542). Perineural catheter fixation with Dermabond in continuous interscalene nerve block improves maintenance of catheter-to-nerve apposition when compared with Mastisol.

The use of two K-wires in cross-leg free flap as a simple fixation technique together with -Y- artery anastomosis

Cross-leg free flap is a method that can be utilized in cases of serious injury where no available recipient vessels can be found in the neighboring sites to defects. Plasters or external fixators are generally used for postoperative immobilization, and generally, one of the major arteries of the uninjured extremity is sacrificed for flap revascularization. Here, we present the -Y- anastomosis method, which obviates the need to resort to major artery sacrifice, used together with K-wire as a simple but influential fixation technique in cross-leg free flap.

Oculomotor Abnormalities in Children with Attention-Deficit/Hyperactivity Disorder Are Improved by Methylphenidate.

There are relatively few studies of saccadic eye movements in children with attention-deficit/hyperactivity disorder (ADHD). The aim of this study was to examine inhibitory abilities of eye movements in children with ADHD and to explore the effect of methylphenidate (MPH) on eye movement performance. Thirty-one children with ADHD (mean age 9.9 ± 0.4 years) and 31 sex-, age-, and IQ-matched children with normal development were examined. Saccades elicited not only by the gap, step, overlap, and antisaccade paradigms but also a simple fixation paradigm have been recorded using an eye tracker. The latency of each type of saccade, the error rate of antisaccades, and the number of saccades made during fixation have been measured. Children with ADHD and naive to treatment with respect to controls showed significantly shorter mean latency of voluntary saccades (overlap paradigm), more frequent errors during the antisaccade paradigm, and higher number of saccades made during fixation. After 1 month of MPH treatment, all these parameters changed significantly and reached control values. Taken together, these results suggest that oculomotor abilities are poor in children with ADHD, which may correlate with deficits in inhibitory mechanisms. Treatment with MPH improves oculomotor performances through adaptive strategies, which may involve brain structures related to cognitive inhibition.

Peripheral contrast sensitivity and attention in myopia

Disruption of normal visual experience or changes in the normal interaction between central and peripheral retinal input may lead to the development of myopia. In order to examine the relationship between peripheral contrast sensitivity and myopia, we manipulated attentional load for foveal vision in emmetropes and myopes while observers detected targets with peripheral vision. Peripheral contrast detection thresholds were measured binocularly using vertical Gabor stimuli presented at three eccentricities (±8°, 17°, 30°) in a spatial 2 alternative forced choice task. Contrast thresholds were measured in young adult (mean age 24.5±2.6years) emmetropes (n=17; group SE: +0.19±0.32D) and myopes (n=25; group SE: −3.74±1.99D). Attention at central fixation was manipulated with: (1) a low attention task, requiring simple fixation; or (2) a high attention task, which required subjects to perform a mathematical task. We found that at 30° all subjects exhibited lower contrast sensitivity (higher thresholds). In addition, myopes (Wilcoxon, p<0.01), but not emmetropes (Wilcoxon, p=0.1), had a significant decrease in sensitivity at 30° during the high attention task. However, the attention dependent threshold increase for myopes was not significantly greater than for emmetropes (Wilcoxon, p=0.27). Attentional load did not increase thresholds at 8° or 17° for either refractive group. These data indicate that myopes experience a greater decrease in contrast sensitivity in the far periphery than emmetropes when attention is deployed in central vision.

Research progress on suture and fixation approach of arthroscopic rotator cuff repair in suture-bridge technique

With advances in arthroscopic surgery, arthroscopic repair for rotator cuff tears is often used by surgeons. Surgical methods have already developed from simple single-row fixation and double-row fixation to complicated suture-bridge fixation. Although arthroscopic suture-bridge rotator cuff repair has been proposed to be advantageous over single-row and double-row fixation in biomechanical constructs, the failure of rotator cuff repair is still higher. Different suture methods of medical row anchor in arthroscopic suture-bridge technique may change the suture-tendon loading and decrease the retear of suture-tendon. And different fixation methods of lateral row anchor in arthroscopic suture-bridge technique may decrease the anchor pull-out. These will be useful to decrease the failure of arthroscopic suture-bridge technique. There will be a good outcome if optical suture and fixation approach can be chosen according to the quality and retraction of rotator cuff, suture tension and the bone quality of the greater tuberosity in arthroscopic suture-bridge technique.

English

Distal fibular fractures are usually communitted and most of the times osteoporotic especially if they are occurring in females and in geriatric age group. These fractures are usually associated with other fractures, which necessitates them to be fixed accurately. Owing to the fact that distal fragment is subcutaneous with scanty soft tissue over bone, which pose these fracture fixations become difficult by open methods in view of wound healing. A prospective study of 26 patients with distal fibular fractures were treated with MIPPO with hook plate were healed with less complications and better outcome. With this background we suggest a minimally invasive incision over proximal fragment where sufficient soft tissue cover is present. From there pushing the special hook plate subperiosteally to distal fragment, hooking the tip of fibula and fixing the proximal fragment after reduction gives a simple and effective stable fixation.

Neuronal Response Gain Enhancement prior to Microsaccades

Neuronal response gain enhancement is a classic signature of the allocation of covert visual attention without eye movements. However, microsaccades continuously occur during gaze fixation. Because these tiny eye movements are preceded by motor preparatory signals well before they are triggered, it may be the case that a corollary of such signals may cause enhancement, even without attentional cueing. In six different macaque monkeys and two different brain areas previously implicated in covert visual attention (superior colliculus and frontal eye fields), we show neuronal response gain enhancement for peripheral stimuli appearing immediately before microsaccades. This enhancement occurs both during simple fixation with behaviorally irrelevant peripheral stimuli and when the stimuli are relevant for the subsequent allocation of covert visual attention. Moreover, this enhancement occurs in both purely visual neurons and visual-motor neurons, and it is replaced by suppression for stimuli appearing immediately after microsaccades. Our results suggest that there may be an obligatory link between microsaccade occurrence and peripheral selective processing, even though microsaccades can be orders of magnitude smaller than the eccentricities of peripheral stimuli. Because microsaccades occur in a repetitive manner during fixation, and because these eye movements reset neurophysiological rhythms every time they occur, our results highlight a possible mechanism through which oculomotor events may aid periodic sampling of the visual environment for the benefit of perception, even when gaze is prevented from overtly shifting. One functional consequence of such periodic sampling could be the magnification of rhythmic fluctuations of peripheral covert visual attention.

Modified Stoppa approach for treatment of fracture of anterior pelvic ring

Objective To evaluate the modified Stoppa approach for treatment of fracture of anterior pelvic ring. Methods From March 2009 to June 2013, 40 patients with fracture of anterior pelvic ring (55 sides) were treated through the modified Stoppa approach at our department. They were 24 males (31 sides) and 16 females (24 sides), aged from 21 to 65 years (average, 34.4 years). According to the Tile classification, 2 cases were type A, 21 cases type B and 17 cases type C. The mean time from injury to surgery was 6.5 days (from 3 to 12 days). Simple plate fixation of the anterior pelvic ring was performed in 23 cases while 17 cases underwent plate fixation of the anterior pelvic ring plus additional fixation of the posterior pelvic ring. The incision length, operation time, blood loss, reduction quality and clinical rehabilitation were documented. Results On average, incision length was 8.2 cm, operation time 78.4 min and blood loss 420 mL for this cohort. According to Matta standard, all the 55 fractures obtained excellent reduction. Intraoperative vascular injury occurred in one case and delayed wound healing after plate removal in another. Of this group, 36 were followed up from 8 to 24 months (average, 18 months) and 4 lost. The fractures healed after 3 to 5.5 months (average, 3.8 months). The functional evaluation by the Majeed system scored an average of 84.4 points. Twenty-one cases were rated as excellent, 13 as good and 2 as fair, resulting in an excellent and good rate of 95.0%. No nonunion, delayed union, malunion or heterotopic ossification was found in the follow-ups. Conclusion In treatment of fracture of anterior pelvic ring, the modified Stoppa approach has advantages of small incision, fine visualization, quality reduction, a low rate of complications and rapid rehabilitation. Key words: Pelvis; Fractures, bone; Fracture fixation, internal; Bone plates; Surgical approach

Radiological study on rat lumbar vertebral semidislocation model

To investigate the impact of fixation in part lumbar segment on rat model with radiography. One hundred and twenty SPF male SD rats (350～450g) were randomly divided into simple fixation group (SF group), rotary fixation group (RF group) and sham-operation group (Sham group). The external link fixation system was implanted into the L4-L6 of SF group and RF group rats. In RF group, L5 spinous process of rats was rotated to the right side, making the L4, L6 and L5 spinous process not in a straight line. In SF group, the external link fixation system was implanted simply and not rotated. The anterior and posterior diameter in the intervertebral space and the distance between spinous processes were examined 1, 4, 8 and 12 weeks after fixation. The anterior diameter in the intervertebral space between L3-L4, L4-L5, L5-L6, and L6-S1 of SF groups 4 weeks after fixation were 28.11 ± 3.94, 25.73 ± 4.70, 29.51 ± 6.34 and 34.97 ± 4.65 pixels; the posterior diameter were 7.39 ± 1.63, 6.65 ± 1.76, 7.02±1.52 and 9.62 ± 2.50 pixels; the distance between spinous process were 39.33 ± 11.74, 14.11 ± 5.75, 21.32 ± 6.84 and 77.43 ± 13.69 pixels, the values were less than those in Sham groups (P<0.05). The anterior and posterior diameter in the intervertebral space and the distance between spinous process of SF groups 8 and 12 weeks after fixation continuously decreased compared with Sham group rats (P<0.05). The results of RF groups were consistent with the measurement of SF groups, the anterior and posterior diameter in the intervertebral space and the distance between spinous process of RF group rats were less than those in Sham groups 4, 8 and 12 weeks after fixation (P<0.05). Osteophyte formation was observed in SF and RF groups 8 weeks after fixation. The fixation in part lumbar segment can result in the decrease of intervertebral space and the formation of osteophytes.