ABSTRACT
Objective To investigate the biomechanical effects of double-headed cannulated compression screws for tibial avulsion fracture of anterior cruciate ligament and the possibility of reducing the risk of intercondylar fossa impingement. Methods Porcine knee joints (30 cases) were taken as experimental samples. Referring to the Meyers classification, it is made into type III fracture. According to the random number table method, they were divided into group A (double-headed cannulated compression screw), group B (cannulated compression screw) and group C (suture), with 10 samples in each group. By detecting the initial displacement and the failure load (peak load and yield load), the nut embedded in the bone block and the failure type were observed to investigate the biomechanical characteristics of the double headed cannulated screw fixation of the fracture. Results The peak load (443.10 ± 8.54) N of group A was not significantly different from that of group C (457.00 ± 26.53) N (P > 0.05), but significantly higher than that of group B (361.70 ± 18.76) N (P < 0.05). The yield load of group A is obviously larger than that of group B (P < 0.05), but it is obviously smaller than the yield load of group C (P < 0.05). The initial displacement of the group A (1.38 ± 0.14) mm was shorter than that of group B and C (1.94 ± 0.12) mm, (3.98 ± 0.19) mm (P < 0.05). The nuts of group A were embedded in the fracture block, and the nuts of group B obviously protruded from the ACL. Conclusions The early biomechanical strength of the anterior cruciate ligament tibial avulsion fracture was significantly better than that of cannulated compression screw and suture, and compared with the cannulated ompression screw, it is difficult to cause intercondylar fossa impingement.
ABSTRACT
Background Eyes with filamentary keratitis present with serious clinical symptoms.This disease is easy to relapse and the treatment is tricky.At present,its pathogenesis is still unclear,and few works were done on filamentous composition.Objective This study was to analyze the composition of corneal filament by imageological and histopathological method,and discuss the formation mechanism of filamentary keratitis.Methods Eighty-eight eyes of 82 cases who suffered from filamentary keratitis were collected in Shandong Eye Hospital between January 2008 and January 2011.The etiologies of the patients were classified and the clinical data were recorded.Firstly,the corneal filiform strip was detected by laser scanning confocal microscopy (LSCM),and the corneal structure was examined by high-definition optical coherence tomography (HD-OCT).Then the composition of filamentary strip was analyzed by Giemsa and Masson trichrome staining of stretched preparation of filiform strip.Results Etiological study showed that filamentary keratitis occurred after penetrating keratoplasty in 40 eyes,after cataract surgery and photorefractive keratectomy (PRK) in 18 eyes,dry eye and neural dystrophic corneal disease in 14 eyes,acute conjunctivitis in 10 eyes.HD-OCT revealed that filament lesion developed to Bowman layer.Filament was composed of epithelial cells,inflammatory cells,mucus and the high reflective strip core with spiral arrangement under the LSCM,and epithelial cells,inflammatory cells and fibrous tissue were seen in the strip core.Giemsa staining exhibited that filament contained corneal epithelial cells,inflammatory cells,mucus and dark blued strip core with helical arrangement.Masson trichrome discovered that the strip core was red fibrous tissue surrounding by blue mucus.Conclusions Epithelial cells,inflammatory cells,mucus and the high reflective strip core with spiral arrangement are the main elements of filament in filamentary keratitis.The lesion can reach Bowman layer.The results contribute to reveal the formation mechanism of corneal filament and assist treatment.
ABSTRACT
Background Pupil atresia increases the difficulty of cataract surgery.The improper enlarging pupil will lead to many complications.The appropriate method of pupil dilation is very important to improve the postoperative effect.Objective This study was to evaluate the pupillary function after manually enlarged pupil to different sizes for pupil atresia complicated cataract.Methods A retrospective case-controlled study was designed.Thirty-eight eyes of 30 cases suffered from pupil atresia complicated cataract induced by chronic uveitis were enrolled in Shandong Eye Institute from May 2006 to May 2012.The eyes underwent pupil forming and phacoemulsification and assigned to the pupil enlarged to ≥6.0 mm group (15 eyes) and 4.5-5.5 mm group (23 eyes).The fibrosis membrane at pupil zone was removed,and the fibrosis strip at pupil collar was cut evenly by 23G intraocular microscissors as zigzag shape.Then the pupil was enlarged in multipoint by a pair of left and right iris hook from the main and lateral incisions.The pupils of 15 eyes in the pupil enlarged to ≥6.0 mm group were dilated above 6.0 mm and 23 pupils in the 4.5-5.5 mm group were dilated to 4.5-5.5 mm and followed by routine phacoemulsification and foldable intraocular lens implantation.Topical and systemic corticosteroids and nonsteroidal anti-inflammatory drugs combined topical mydriatic were applied before and after operation.The pupil diameter,light reflex and photophobia symptom in postoperation were compared between the two groups.The visual acuity before and after operation and intra-and post-operative complications were recorded.This study was approved by Ethic Committee of Shandong Eye Hospital,and written informed consent was obtined from each patient before operation.Results The pupil diameter in the pupil enlarged to ≥6.0 mm group was dilated to (6.9±0.4) mm and that of the 4.5-5.5 mm was dilated to (5.1 ±0.3) mm intraoperatively,with a statistical significance between them (t =16.100,P =0.000).Three months later,the pupil diameter in the pupil enlarged to ≥ 6.0 mm group was (4.9 ±0.4)mm,with different degrees of lacerated pupillary margins,and that in the pupil enlarged to 4.5-5.5 mm group was (3.5 ±0.5) mm,with rare lacerated pupillary margins,showing a statistically significant difference (t =9.820,P =0.000).The unresponsive or obtuse light reflex in the pupil enlarged to ≥6.0 mm group was significantly higher than in the pupil enlarged to 4.5-5.5 mm group(11 eyes vs.6 eyes) (x2 =8.200,P =0.005).The subjective photophobia symptom of 2-3 grades in the pupil enlarged to ≥6.0 mm group was in 12 eyes,which was higher than that in the pupil enlarged to 4.5-5.5 mm group (2 eyes) (H=19.840,P=0.000).The iris haemorrhage were seen in 3 eyes in the pupil enlarged to 4.5-5.5 mm group and 7 eyes in the pupil enlarged to ≥6.0 mm group (x2 =5.290,P=0.030).The visual acuities of the operated eyes in the two groups improved at different degrees.Conclusions Approximate physiological pupil and good visual quality can been obtained by manual releasing and enlarging pupil to less than 5.5 mm evenly during the surgery for pupil atresia complicated cataract induced by chronic uveitis.