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To design and investigate a novel technique of percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion. CT scans of 45 patients were collected and imported into Mimics software for three-dimensional (3D) reconstruction. Cylinders were drawn to simulate the trajectory of the oblique screw. Six measurements were obtained for each unit to design a right size cage: a the distance between the intersection of the simulated trajectory of the screw with the inferior border of the upper vertebra and its anteroinferior corner; b the distance between the intersection of the simulated trajectory of the screw with the superior border of the inferior vertebra and its anterosuperior corner; h the height of the intervertebral space; θ the angle between simulated trajectory of screw and the upper endplate of inferior vertebra; uw: the width of the inferior endplate of upper vertebra; iw: the width of upper endplate of inferior vertebra. Three intact adult fresh-frozen cadaveric specimens were obtained, percutaneous posterior transdiscal oblique screw fixation was performed under X-ray apparatus, and interbody cage was implanted by assistance with special self-retaining retractor system and endoscope. According to the results of data measured from 3D images, trapezoid shape interbody cages with suitable size were designed. Percutaneous posterior oblique screw fixation with lateral interbody fusion was performed on three cadaveric specimens successfully. Using specially designed trapezoid shape interbody cages, assisted by intra-operative image intensification and endoscope, it is feasible to perform percutaneous posterior transdiscal oblique screw fixation with lateral interbody fusion technique.

The purpose of this study was to determine whether it would be feasible to use oblique lumbar interbody fixation for patients with degenerative lumbar disease who required a fusion but did not have a spondylolisthesis. A series of CT digital images from 60 patients with abdominal disease were reconstructed in three dimensions (3D) using Mimics v10.01: a digital cylinder was superimposed on the reconstructed image to simulate the position of an interbody screw. The optimal entry point of the screw and measurements of its trajectory were recorded. Next, 26 cadaveric specimens were subjected to oblique lumbar interbody fixation on the basis of the measurements derived from the imaging studies. These were then compared with measurements derived directly from the cadaveric vertebrae. Our study suggested that it is easy to insert the screws for L1/2, L2/3 and L3/4 fixation: there was no significant difference in measurements between those of the 3-D digital images and the cadaveric specimens. For L4/5 fixation, part of L5 inferior articular process had to be removed to achieve the optimal trajectory of the screw. For L5/S1 fixation, the screw heads were blocked by iliac bone: consequently, the interior oblique angle of the cadaveric specimens was less than that seen in the 3D digital images. We suggest that CT scans should be carried out pre-operatively if this procedure is to be adopted in clinical practice. This will assist in determining the feasibility of the procedure and will provide accurate information to assist introduction of the screws. Cite this article: Bone Joint J 2013;95-B:977–82.

Glaucoma is the leading cause for blindness affecting 60 million people worldwide. The optineurin (OPTN) E50K mutation was first identified in familial primary open-angle glaucoma (POAG), the onset of which is not associated with intraocular pressure (IOP) elevation, and is classified as normal-tension glaucoma (NTG). Optineurin (OPTN) is a multifunctional protein and its mutations are associated with neurodegenerative diseases such as POAG and amyotrophic lateral sclerosis (ALS). We have previously described an E50K mutation-carrying transgenic (E50K-tg) mouse that exhibited glaucomatous phenotypes of decreased retinal ganglion cells (RGCs) and surrounding cell death at normal IOP. Further phenotypic analysis of these mice revealed persistent reactive gliosis and E50K mutant protein deposits in the outer plexiform layer (OPL). Over-expression of E50K in HEK293 cells indicated accumulation of insoluble OPTN in the endoplasmic reticulum (ER). This phenomenon was consistent with the results seen in neurons derived from induced pluripotent stem cells (iPSCs) from E50K mutation-carrying NTG patients. The E50K mutant strongly interacted with TANK-binding kinase 1 (TBK1), which prohibited the proper oligomerization and solubility of OPTN, both of which are important for OPTN intracellular transition. Treatment with a TBK1 inhibitor, BX795, abrogated the aberrant insolubility of the E50K mutant. Here, we delineated the intracellular dynamics of the endogenous E50K mutant protein for the first time and demonstrated how this mutation causes OPTN insolubility, in association with TBK1, to evoke POAG.

To investigate the feasibility of mini-open anterior approach to the cervicothoracic junction (CTJ) in cadaveric specimens.Four adult fresh-frozen cadaveric specimens were used for this study. On the cadaveric specimen, an osteotomy window was made in manubrium sterni to remove the bony obstacle. To bypass the vital vascular and neural structures over the operative field, we used the surgical corridor which was located medially by the brachiocephalic artery and laterally by the right brachiocephalic vein, or in combination with another surgical corridor between the ascending aorta and the superior vena cava. And we used a special self-retaining retractor system and an endoscope to facilitate the procedures.Surgical procedures performed on the four fresh-frozen cadaveric specimens to expose the CTJ through mini-open anterior approach were successful. The anterior surface of C6-T5 could be exposed, allowing complete decompression and application of locking plate and screws. The most caudal accessible vertebral body was T5 vertebral body in our study.It is feasible to expose the CTJ through this mini-open anterior approach.

To determine the location of left brachiocephalic vein (BCV) and tracheal bifurcation (TB) relative to the vertebral levels, and to ascertain the accessibility of three different corridors (C1: between the esophagus and trachea medially and the carotid sheath laterally, C2: between the right BCV and the brachiocephalic artery, and C3: between the ascending aorta and superior vena cava) for preoperative planning. From August 2008 to April 2009, normal chest CT scans of 150 subjects ranging in age from 18 to 78 years were selected. According to our definition, of the 150 studies, 132 T2 vertebral bodies (VBs) could be accessed through C1 (88.0%), 100 T3 VBs could be reached through C2 (66.7%), and 110 T4 VBs could be exposed through C3 (73.3%). The results suggest that the surgical accessibility of three different corridors is different and we conclude that T2, T3, and T4 are, respectively, readily accessible through C1, C2, and C3.

STUDY DESIGN Laminoplasty was simulated using a computer-assisted technique to assess the amount of canal expansion. OBJECTIVES This study was designed to clarify the relationship between laminoplasty opening size and increase in sagittal canal diameter, increase in canal area, and the angle of the opened lamina following laminoplasty, and to determine whether a spinous process-splitting laminoplasty achieves the similar canal expansion as a single open-door method. SUMMARY OF BACKGROUND DATA Single and double-door cervical laminoplasty (SDCL and DDCL, respectively) have been widely used in the treatment of multilevel stenotic conditions. However, the relationship between laminoplasty opening size and spinal canal expansion following laminoplasty, and the comparison of postoperative spinal canal expansion between single and double-door techniques have not been well investigated. METHODS SDCL and DDCL, based on preoperative computerized tomography scans of 34 patients who had undergone the laminoplasty surgery, were simulated using a computer-assisted technique. Laminoplasty with an opening size of 6, 8, 10, 12, 14, 16, and 18 mm were simulated to determine the amount of canal enlargement with the various opening size. RESULTS Sagittal diameter, canal area, and lamina angle were increased steadily following either single or double-door laminoplasty with the door opened from 6 to 18 mm. Significant positive correlation was found between laminoplasty opening size and increase in sagittal diameter (R2 = 0.969 and P = 0.001 in SDCL; R2 = 0.926 and P < 0.001 in DDCL), increase in canal area (R2 = 0.961 and P < 0.001 in SDCL; R2 = 0.937 and P < 0.001 in DDCL), and lamina angle (R2 = 0.959 and P < 0.001 in SDCL; R2 = 0.943 and P < 0.001 in DDCL). No significant correlation was observed between preoperative sagittal diameter and increase in sagittal diameter of the spinal canal, whereas significant positive correlation was found between preoperative cross-section area and increase in cross-section area of the spinal canal. The differences between postoperative canal increase in sagittal diameter and canal area for the single versus double-door technique were statistically significant when the door was opened by more than 12 mm (P < 0.05). CONCLUSIONS Our investigation provides insight into canal expansion after laminoplasty. The increased amount of canal following laminoplasty can be predicted by the regression equations. This may allow preoperative determination of the optimal size of the opening needed to establish adequate canal space for the spinal cord. Both single and double-door techniques of laminoplasty provide sufficient room for posterior migration of the spinal cord, although gaining different canal expansion.

Anterior occiput-to-axis screw fixation is more suitable than a posterior approach for some patients with a history of posterior surgery. The complex osseous anatomy between the occiput and the axis causes a high risk of injury to neurological and vascular structures, and it is important to have an accurate screw trajectory to guide anterior occiput-to-axis screw fixation. Thirty computed tomography (CT) scans of upper cervical spines were obtained for three-dimensional (3D) reconstruction. Cylinders (1.75 mm radius) were drawn to simulate the trajectory of an anterior occiput-to-axis screw. The imitation screw was adjusted to 4 different angles and measured, as were the values of the maximized anteroposterior width and the left-right width of the occiput (C0) to the C1 and C1 to C2 joints. Then, the 3D models were printed, and an angle guide device was used to introduce the screws into the 3D models referring to the angles calculated from the 3D images. We found the screw angle ranged from α1 (left: 4.99 ± 4.59°; right: 4.28 ± 5.45°) to α2 (left: 20.22 ± 3.61°; right: 19.63 ± 4.94°); on the lateral view, the screw angle ranged from β1 (left: 13.13 ± 4.93°; right: 11.82 ± 5.64°) to β2 (left: 34.86 ± 6.00°; right: 35.01 ± 5.77°). No statistically significant difference was found between the data of the left and right sides. On the 3D printed models, all of the anterior occiput-to-axis screws were successfully introduced, and none of them penetrated outside of the cortex; the mean α4 was 12.00 ± 4.11 (left) and 12.25 ± 4.05 (right), and the mean β4 was 23.44 ± 4.21 (left) and 22.75 ± 4.41 (right). No significant difference was found between α4 and β4 on the 3D printed models and α3 and β3 calculated from the 3D digital images of the left and right sides. Aided with the angle guide device, we could achieve an optimal screw trajectory for anterior occiput-to-axis screw fixation on 3D printed C0 to C2 models.

We sought to evaluate the motor-sensory specificity of the motor and primary sensory neurons after the end-to-side neurorrhaphy. We divided 90 rats into three groups: (1) end-to-side neurorrhaphy using the ulnar nerve as donor nerve and the musculocutaneous nerve as recipient nerve; (2) normal control; and (3) transected nerve with the stumps buried. At 5 months, we monitored the grooming test, the electromyographic recordings, the histologic changes in the nerve, and quantitatively evaluated motoneurons and dorsal root ganglion (DRG) neurons following their retrograde labeling by Fluoro-Gold (Sigma, St. Louis, MO) applied to the musculocutaneous nerve and its biceps brachii branch. Grooming and electrophysiological investigations recovered successfully in the end-to-side group. The implanted musculocutaneous nerve contained varying but satisfactory numbers of axons. In the end-to-side group, the proportion of motoneurons for the biceps brachii branch of musculocutaneous nerve was very similar to the musculocutaneous nerve sections proximal to this branch (17.3% ± 2.7% and 21.7% ± 3.7%, respectively), but it did not correspond with the proportion of the biceps brachii branch of musculocutaneous nerve in the normal group (28.3% ± 3.5%). The present study confirms that limited but functional reinnervation can occur after the end-to-side neurorrhaphy, and the motor-sensory specificity is not important.

To establish reference data on the dimensions of C2 lamina to guide the use of translaminar screws with Wright’s technique and a modified technique for pediatric patients in different age groups. 113 pediatric patients were divided into six age groups, and their cervical vertebrae were studied on CT scans. Laminar height, width, length and screw angle were measured. Statistical analysis was performed using Student t tests, Pearson’s correlation and linear regression analysis. Mean laminar height was 10.95 ± 2.81 mm, and mean width was 6.01 ± 0.90 mm. For Wright’s technique, mean laminar length was 30.65 ± 3 mm, and the screw angle was 56.02° ± 3.62°. For the modified technique, mean laminar length was 22.07 ± 2.38 mm, and the screw angle was 67.40° ± 3.39°. 95.6 % (108/113) of the children could insert a screw into the lamina (laminar width ≥4.5 mm), 72.6 % (82/113) could accept bilateral translaminar screws (laminar width ≥4.5 mm and laminar height ≥9 mm). Our investigation provides insight into the anatomy of C2 lamina in six pediatric age groups. Compared to adults, the benefits of C2 translaminar screws fixation are more obvious in the pediatric spine which has a large C2 lamina. Compared to Wright’s technique, the modified technique should insert a screw with bigger insert angle and shorter screw length.

Background:Surgical treatments for adult spinal deformities often include pelvic fixation, and the feasibility of sacral-2 alar iliac (S2AI) screw fixation has been shown previously. However, sometimes S2AI screw fixation cannot be applied due to the presence of an osteolytic lesion or trauma or because the biomechanical properties of only an S2AI screw is insufficient. Therefore, we questioned the feasibility of using sacral AI screws in other segments and determined whether S3AI and S4AI screws have the potential to be used for sacral fractures. The aim of this study was to investigate the feasibility and radiological features of sacral AI fixation in S1–S4 in an adult population using 3D imaging techniques.Methods:Computed tomography (CT) scans were taken of 45 patients and were imported into Mimics (Version 10.01, Materialise, Belgium) software to reconstruct the 3D digital images. Next, a cylinder (radius of 3.5 mm) was drawn to imitate the screw trajectory of a S1–4 AI screw, and every imitated screw in each segment was adjusted to a maximum upward and downward angle to acquire the feasible region. The parameters of the S1–4AI screw trajectories were measured.Results:Sacral AI screws could be successfully imitated using 3D digital imaging. The S4AI screw trajectory could be obtained in 19 of 45 patient images (42.2%), while the feasibility rates of S1AI, S2AI, and S3AI screw fixation were 100%, 100%, and 91.1% (41/45), respectively. The feasible regions of S1AI, S2AI, and S3AI screw trajectories were wide enough, while the adjustable angle of S4AI screws was very small.Conclusion:It is feasible to place S1–2AI screws in the entire adult population and S3–4AI screws in some of the adult population. Furthermore, our study suggested that 3D digital images are suitable to study the feasibility of new screw fixation.

To study the anatomic parameters related to clival screw and establish reference data concerning the craniovertebral fixation technique.Morphometric measurement of the clivus and the surrounding anatomic structures were obtained on 41 dry bone specimens. Then, 2-D CT reconstruction of the craniovertebral region of 30 patients (19 men and 11 women, ranging in age from 20-64 years with an average age of 38.8 years) were performed to measure the safety range for a 3.5-mm screw placement. Nine entry points were evaluated. Finally, one male fresh cadaver specimen (age 46 years) was dissected to observe the craniovertebral region.The clivus faces the basilar artery, the V ~ XII cranial nerves, the pons, and ventral medulla oblongata at its intracranial surface. The longitudinal diameter of extracranial clivus was 25.87 ± 2.64 mm. The narrowest diameter of the clivus was 12.84 ± 1.08 mm, the distance between the left and right hypoglossal canal was 32.70 ± 2.09 mm at its widest part. The distance between the left and right structures, the maximum value was 49.31 ± 4.16 mm at carotid canal, the minimum value was 16.54 ± 2.04 mm at the occipital condyle. The measurement of clival screws placement simulation via 2-D CT reconstruction images shows the maximum upper insertion angle of three components the optimal entry points, the candidate points, the limit entry points was 130.19°, 125.23° and 85.72°, and the total mean screw length was 7.57, 10.13 and 15.6 mm at the vertical entry angle, respectively.Clival screw placement is a viable option for craniovertebral fixation. There is a safe scope for the screw length and angle of the screw placement. And, these parameters obtained in the present study will be helpful for anyone contemplating the use of clival screw fixation.

Purpose To evaluate the quality of regenerating myelinated axons and motor-sensory specificity in an end-to-side nerve repair model. Methods We divided 20 rats into 3 groups: (1) end-to-side neurorrhaphy using the ulnar nerve as donor nerve and the musculocutaneous nerve as recipient nerve; (2) normal control; and (3) transected nerve with the stumps buried. At 5 months, we monitored the grooming test, the electrophysiological response, and the histologic changes in nerve and muscle. Results Grooming recovered successfully, and electrophysiological investigations revealed that the target muscles had been reinnervated in the end-to-side group. The mean wet weight of the reinnervated biceps brachii muscle was 72% of the normal muscle, and the mean muscle fiber cross-sectional area of the reinnervated muscle was similar to the normal muscle. The implanted musculocutaneous nerve contained varying but satisfactory numbers of axons (end-to-side group: 596 ± 348 vs normal group: 1,340 ± 241). Acetylcholinesterase staining revealed a similar percentage of myelinated fibers in the musculocutaneous nerve (39%) and the biceps brachii branch of the musculocutaneous nerve (38%) in the end-to-side group. This was similar to the number of myelinated fibers in the donor ulnar nerve (37%). Conclusions The present study confirms that limited but functional reinnervation can occur on the basis of collateral sprouting of intact axons from the ulnar nerve. The motor-sensory specificity is not important.

This research aimed to construct three-dimensional (3D) visible models of the superior mediastinum for anatomic study and surgical approaches to the superior mediastinum. Sectional images of the superior mediastinum were acquired through the Chinese Visible Human Female (VCHF) database. One hundred eighty images of the superior mediastinum were imported into Photoshop CS and the images were converted into a JPEG format. Surface and volume reconstruction were performed by 3D Doctor 3.5 and Amira 4.0 software programs on an ordinary personal computer, respectively. The surface and volume reconstruction of the superior mediastinum were successful. The surface reconstruction model allowed rotation and magnification of the superior mediastinum structures as well as displayed the contours of reconstructed structures individually or as a composite with any other selected structure. Volume reconstruction displayed abundant internal detail of reconstructed images in transverse, coronal, sagittal, and random oblique sections. Three-dimensional, visible models of the superior mediastinum based on the sectional images of VCHF can provide unique insight into the anatomy of superior mediastinum. These models provide an excellent adjunct to the anatomy curriculum in medical schools and an invaluable tool for the practicing surgeon planning an operation in this complex anatomic region.

A fractured vertebra does not transfer load as effectively as the intact vertebra. Patients who undergo surgery using short-segment pedicle screw instrumentation for middle-column injury may experience implant failure when vertebral body comminution is ignored. The purpose of this study was to investigate biomechanical effects of the extent of vertebral body fracture on the thoracolumbar spine after pedicle screw fixation and to evaluate the biomechanical role of anterior reconstruction. Twelve fresh porcine T12-L3 specimens were harvested and divided into two groups. A 2-mm drill bit was used to create holes in the L1 vertebra with two different extents: 1/6 and 1/3 vertebral body involvement. After the pre-injury had been created, specimens were subjected to flexion-compression to create a fracture in the body of the spine. Stiffness under axial-compression and flexion-compression were measured in intact specimens, after the fractured segments had been stabilized using transpedicular fixation, and after transpedicular fixation with anterior grafting. Despite fixation of the injured spine with pedicle screw instrumentation, the axial-compression and flexion-compression stiffness was still significantly lower than that of the intact group (p