Objective To assess the possibility of placing the posterior pedicle screw on atlas. Methods Twenty human cadaver specimens were used to insert pedicle screws in atlas, through the posterior arch or the pedicle of C1 into the lateral mass. The screw entry point was on the posterior surface of C1 posterior arch and at the intersection of the vertical line through the center of C2 inferior articular process and the horizontal line at least 3 mm below the superior rim of the C1 lamina. The screw of 3.5 mm in diameter was placed in a direction of 10° medial angle and 5° upwardangle. After placement of C1 pedicle screw, the distance from C1 screw entry point to the mediallateral midpoint of C1 pedicle, the maximum length of screw trajectory and the actual screw trajectory angles were measured. The direction of screw penetrating through the cortical of C1 pedicle or lateral mass and the injuries to the vertebral artery and spinal cord were observed.Results Forty pedicle screws were placed on atlas, the mean distance from C1 screw entry point to the medial-lateral midpoint of C1 pedicle was (2.20±0.42)mm, the maximum length of screw trajectory averaged (30.51±1.59)mm, and the actual screw trajectory angle measured (9.7±0.67)° in a medial direction and (4.6±0.59) ° in a upward direction. Only 1 screw penetrated the upper cortical bone of the atlas pedicle because the upward angle was too large, and 8 screws were inserted so deep that the inferior cortical bone of the C1 lateral mass was penetrated. But no injuries to the vertebral artery and spinal cord wereobserved. Conclusion C1 posterior pedicle screw fixation is quite accessible and safe, but the su
Objective To reveal the fibrillar network in vitreous and the effect of plasmin on this network.Methods 20 vitreous gels of freshly slaughtered pigs were divided into 2 groups, the gels in first group were digested by 3 Uplasmin (3 U/ml) at 37c for 24 hours respectively, the second group received the same PBS as control. After digestion, gels were fixed in neutral buffered formalin solution. Samples from vitreous base, cortex and the central region were observed by the technique of freeze etching electron microscopy.Results In vitreous collagen fibril network was in a three-dimensional array, collagen fibril density showed marked differences, central vitreous had the sparse fibril density, the cortex denser and the basal vitreous densest. After digestion by plasmin, the collagen fibrillar network was destructed.Conclusion Collagen fibrils in vitreous present spatial arrangement regularly, plasmin can lead to destruction of the fibrillar network.(Chin J Ocul Fundus Dis，2003，19：179-181)
ObjectiveTo help junior radiologists and surgeons better interpret MRI images of rectal cancer.MethodThe guidelines, expert consensus and research progress on the application of MR imaging in rectal cancer in recent years were reviewed.ResultsRectal MR had the ability to accurately evaluate a number of important findings that may impact patient’ management, including distance of the tumor to the mesorectal fascia, presence of extramural vascular invasion, and presence of lymph nodes.ConclusionsRectal MRI is an important basis for clinical staging and multidisciplinary diagnosis and treatment of rectal cancer. Surgeons and radiologists must master the key imaging anatomical basis and clinical practice points in order to accurately interpret the image information of MRI in rectal cancer.
Objective To measure the anatomical parameters related to lumbar unilateral transverse process-pedicle percutaneous vertebral augmentation, and to assess the feasibility and safety of the approach. Methods A total of 300 lumbar vertebral bodies of 60 patients were randomly selected, and vertebral augmentation were simulated 600 times on X-ray and CT image with unilateral conventional transpedicle approach (control group) and unilateral transverse process-pedicle approach (experimental group). The distance between the entry point and the midline of the vertebral body, the puncture inner inclination angle, the safe range of the puncture inner inclination angle, and the puncture success rate were measured and compared between the left and right with the same approach, and between the two approaches. Results The distance between the entry point and the midline gradually increased from L1 to L5 on both sides in the 2 groups. In the control group, the right sides distance of L1 and L2 was much longer than the left sides, and the right sides distance of L1, L2, and L5 was much longer than the left sides in the experimental group (P<0.05); the distance of the experimental group between the entry point and the midline was much longer than the control group regardless of the sides from L1 to L5 (P<0.05). In the experimental group, the right maximum inner inclination angle from L1 to L5, the right middle inner inclination angle from L1 to L5, and the right minimum inner inclination angle from L1, L2, L4, L5 were significantly larger than the left side (P<0.05). The maximum inner inclination angle and the middle inner inclination angle presented increased tendency, the tendency of minimum inner inclination angle was ambiguous, however, the all inner inclination angles were much larger than those in control group among the different lumbar levels(P<0.05). There was no significant difference of the safe range of the puncture inner inclination angle between 2 sides in 2 groups at L1 to L5 (P<0.05); the safe range angle in experimental group at L5 was significantly smaller than that in control group (P<0.05). The difference in total puncture success rate of all lumbar levels was significant between the experimental group and the control group (χ2=172.252, P=0.000); the puncture success rates of the experimental group were higher than those in the control group form L1 to L4 (P<0.05), but no significant difference was found in the puncture success rate between 2 groups at L5 (P>0.05). Conclusion Compared with the unilateral conventional transpedicle approach, the entry point of the unilateral transverse process-pedicle approach is localized outside, the puncture inclination angle is wider, and the puncture success rate is higher. It shows that the unilateral transverse process-pedicle approach is safer and more reliable than the unilateral conventional transpedicle approach.
Objective To demonstrate the anatomical and biomechanical basis of scaphoid ring sign in advanced Kienbock’s disease. Methods The study consisted of two sections. The ligaments stabilizing the proximal pole of the scaphoid were observed in 5 specimens. Under 12 kg dead weight load through the tendons of the flexion carpal radial, the flexion carpal ulnar, the extension carpal radial, and the extension carpal ulnar for 5 minutes, the stresses of the scaphoid fossa and lunate fossa were measured in the case of neutral, flexion, extension, radial deviation and ulnar deviation of the wrist joint under normal and rupture conditions respectively by FUJI prescale film and FPD-305E,306E.Results Based on anatomical study, the ligaments stabilizing the proximal pole of the scaphoid consisted of the radioscaphocapitate ligament, long radiolunate ligament and scapholunate interosseous ligament; and the latter two ligaments restricted dorsal subluxation of the proximalpole of the scaphoid. When compared rupture condition with normal condition, thescaphoid fassa stress of radial subregion was not significantly different (0.90±0.43 vs 0.85±0.15), and the ones of palmar, ulnar and dorsal subregions decreased (0.59±0.20, 0.52±0.05 and 0.58±0.23 vs 0.77±0.13, 0.75±0.08 and0.68±0.09) in the case of extension; the scaphoid fassa stresses of all subregions increased or had no difference in the case of neural, flexion, radial deviation and ulnar deviation. The lunate fossa stresses of all subregions increased in thecase of neural, and the ones of all subregions decreased or had no difference inthe case of flexion, extension, radial deviation and ulnar deviation.Conclusion Rotary scaphoid subluxation should be treated operatively at Ⅲ B stage of Kienbock’s disease to avoid traumatic arthritis of theradioscaphoid joint.
Objective To review the recent anatomy and biomechanical research progress of knee posteromedial corner, to analyze deficient aspect, and to predict future research directions. Methods Domestic and international l iterature about the anatomy and function of knee posteromedial corner in recent years was reviewed extensively, at the same time, the biomechanics of corresponding structure was summarized and analyzed. Results The anatomical structures ofknee posteromedial corner included the static stabil ity structures and the dynamic stabil ity structures. The dynamic stabil ity structures were more important, including posterior root of medial meniscus, posterior obl ique l igament, semimembranosus extensions, meniscotibial l igament and obl ique popl iteal l igament. The posterior obl ique l igament was most important structure to contribute to stabil ization of valgus, anterior internal rotation of knee and posterior movement of tibia. Conclusion Anatomical reconstruction of knee posteromedial corner especially the posterior obl ique l igament is the key to the reconstruction of knee posteromedial function stabil ity.
ObjectiveTo study the significance, methods, and technique of group No.6 lymphadenectomy of the laparoscopic gastrectomy with D2 lymph node dissection for distal gastric cancer. MethodsThe relevant data of the 141 examples of group No.6 lymphadenectomy of the laparoscopic gastrectomy with D2 lymph node dissection for distal gastric cancer from Jan.1, 2008 to Dec.31, 2011 were retrospectively analysized. ResultsOne hundred and forty-one patients were successfully completed the group No.6 lymphadenectomy of laparoscopic distal gastrectomy with D2 lymph node dissection. With the number of cases of operation increasing, the operation time, bleeding volume, incidence rate of complication, and the number of operation transit cases stepped down year by year, and the number of the lymph node dissection stepped up (P < 0.000 1). No case died of the lymphadenectomy of the group No.6 lymph node. The medium vessels of colon, pancreas, and the gastroduodenal artery were the anatomic landmarks of the group No.6 lymphadenectomy. The space between the anterior lobe and the posterior lobe of transverse mesocolon and the prepancreatic space were the important surgical plane to carry out the group No.6 lymphadenectomy. ConclusionsOnly a team shall complete a certain amount of the operation, take the medium vessels of colon, pancreas, and the gastroduodenal artery as the anatomic landmark, accurately identify the space between the anterior lobe and the posterior lobe of transverse mesocolon, and the prepancreatic space, and take operation on the correct surgical plane, shall the group No.6 lymphadenectomy conform to the principle of the radical cure of the tumour and achieve the aim of the minimal invasion.
ObjectiveTo observe the macular choroidal and retinal pigment epithelium (RPE) thickness in tilted disc syndrome (TDS). MethodsThis is a descriptive study. Thirty eyes of 22 TDS patients (TDS group) and 30 eyes of 15 normal subjects (control group) were analyzed. Among TDS group, there were 8 males (11 eyes) and 14 females (19 eyes), the average age was (9.00±2.78) years old. The best corrected visual acuity (BCVA) was 0.3-1.0, and the average spherical equivalent degree was (-3.44±2.22) DS. Among the control group, there were 8 males (16 eyes) and 7 females (14 eyes), the average age was (9.33±1.11) years old. The best corrected visual acuity (BCVA)≥1.0, and the average spherical equivalent degree was (-3.18±1.13)DS. The difference of the spherical equivalent degree between two groups was not statistically significant (t=-1.648, P=0.110). Enhanced depth imaging techniques of frequency-domain optical coherence tomography was used to measure the thickness of choroid and RPE at totally 17 sites. There sites included subfoveal, 4 sites each (500, 1000, 1500 and 2000 μm from the fovea) at the horizontal (nasal/temple) and vertical (superior/inferior) directions. ResultsThe subfoveal choroidal thickness was (235.53±51.77) μm and (273.45±60.3) μm in TDS patients and control respectively, the difference was significant(t=-2.612,P=0.011). The difference of the choroidal thickness of the other 8 horizontal sites (F=24.180) and 8 vertical sites (F=23.390) in TDS group was statistically significant (P=0.000). The TDS choroidal thickness of all horizontal sites except nasal 1000 μm site was thinner than corresponding sites of the control group (P<0.05). The TDS choroidal thickness of the subfoveal site and 4 inferior vertical sites was thinner than corresponding sites of the control group (P<0.05). The subfoveal RPE thickness was (32.56±5.00) μm and (36.58±3.60) μm in TDS patients and control respectively, the difference was significant(t=-3.567,P=0.001). The subfoveal RPE thickness was the thickest among other 16 sites in both groups, and the TDS RPE thickness of all sites was thinner than control group, the difference was statistically significant (P<0.05). ConclusionThe choroidal and RPE thickness of TDS patient was thinner than normal subjects.