Guanyi Liu

Posterior short-segment fixation and fusion in unstable Hangman's fractures.

Study Design. A retrospective study. Objective. To introduce the method of C2–C3 posterior short-segment fixation and fusion in unstable Hangmans fracture and to evaluate the clinical effects. Summary of Background Data. Hangmans fracture can be managed by closed reduction and immobilization. However, surgery is usually preferable in highly unstable cases and in rigid arthrodesis failure. The outcome of surgical treatment for unstable Hangmans fracture has not been thoroughly investigated. Methods. Thirty-five patients with unstable Hangmans fracture were treated using C2–C3 posterior short-segment fixation and fusion. Twenty-six cases used C2–C3 short-segment pedicle screw fixation. Nine cases used both C2 pedicle screw and C3 lateral mass screw short-segment fixation and fusion. C-arm fluoroscopy was used for the whole procedure. Results. All patients were observed for an average of 44 months, ranging from 12 to 78 months. There was no screw loosening or breakage, nor was there any spinal cord or vertebral artery injury intraoperatively. A total of 140 screws were placed, with 70 screws inserted into the C2 pedicle, 52 into the C3 pedicle, and 18 into the C3 lateral mass. Computed tomography scans indicated 9 screws were placed too close to the vertebral artery canal in C2, and 12 screws were too close to the canal in the C3 pedicle, all without clinical consequences. C3 lateral mass screws were placed successfully. Neurologic status improved from C and D to E in all 8 cases. Static and dynamic films demonstrated that fusion was achieved in all cases 6 months after surgery. No graft or plate-related complications were observed in any patients during the entire follow-up period. Conclusion. C2–C3 posterior short-segment fixation and fusion is an effective method for the management of unstable Hangmans fracture, proving its value as a tech-nique for achieving solid bony fusion combined with a low rate of complications.

Clinical application of C2 laminar screw technique.

C2 laminar screws have become an increasingly used alternative method to C2 pedicle screw fixation. However, the outcome of this technique has not been thoroughly investigated. A total of 35 cases with upper cervical spinal instability undergoing C2 laminar screw fixation were reviewed. All cases had symptoms of atlantoaxial instability, such as craniocervical junction pain, and were fixed with the Vertex cervical internal fixation system. A total of 68 screws were placed and hybrid constructs (a C2 translaminar screw combined with a C2 pars screw) were incorporated in two patients. In this series, there were no intraoperative complications and no cases of neurological worsening or vascular injury from hardware placement. Computed tomographic scans demonstrated a partial dorsal laminar breach in ten patients. None of these resulted in neurological symptoms. None of the patients was found to have a breach of the ventral laminar cortex. All the C2 laminar screws fixations were performed successfully. There was no instability seen on the films with no evidence of hardware failure or screw loosening during the follow-up period in all patients. In conclusion, C2 laminar screw technique is straightforward and easily adopted; it can efficiently and reliably restore upper cervical stability. It is an alternative method to C2 pedicle screw fixation, especially in patients with unilateral occlusion of vertebral artery and pedicle deformity of C2.

Biomechanical comparison of pedicle screws versus spinous process screws in C2 vertebra A cadaveric study

Background: Biomechanical studies have shown C2 pedicle screw to be the most robust in insertional torque and pullout strength. However, C2 pedicle screw placement is still technically challenging. Smaller C2 pedicles or medial localization of the vertebral artery may preclude safe C2 pedicle screw placement in some patients. The purpose of this study was to compare the pullout strength of spinous process screws with pedicle screws in the C2. Materials and Methods: Eight fresh human cadaveric cervical spine specimens (C2) were harvested and subsequently frozen to −20°C. After being thawed to room temperature, each specimen was debrided of remaining soft tissue and labeled. A customs jig as used to clamp each specimen for screw insertion firmly. Screws were inserted into the vertebral body pairs on each side using one of two methods. The pedicle screws were inserted in usual manner as in previous biomechanical studies. The starting point for spinous process screw insertion was located at the junction of the lamina and the spinous process and the direction of the screw was about 0° caudally in the sagittal plane and about 0° medially in the axial plane. Each vertebrae was held in a customs jig, which was attached to material testing machine (Material Testing System Inc., Changchun, China). A coupling device that fit around the head of the screw was used to pull out each screw at a loading rate of 2 mm/min. The uniaxial load to failure was recorded in Newtonst dependent test (for paired samples) was used to test for significance. Results: The mean load to failure was 387 N for the special protection scheme and 465 N for the protection scheme without significant difference (t = −0.862, P = 0.403). In all but three instances (38%), the spinous process pullout values exceeded the values for the pedicle screws. The working distances for the spinous process screws was little shorter than pedicle screws in each C2 specimen. Conclusion: Spinous process screws provide comparable pullout strength to pedicle screws of the C2. Spinous process screws may provide an alternative to pedicle screws fixation, especially with unusual anatomy or stripped screws.

The study on comparison of 3 techniques for transarticular screw placement in the lower cervical spine.

Study Design. Prospective comparative study. Objective. To compare 3 techniques for transarticular screw placement in the lower cervical spine. Summary of Background Data. The transarticular screw is found to have satisfactory biomechanical stability. According to current studies, there are several techniques for the placement of transarticular screws in the lower cervical spine. Although several techniques are available for transarticular screw implantation in the lower cervical spine, only a few studies in the literature have been carried out to compare these techniques. Methods. The techniques of transarticular screw placement used by Takayasu (group A), Dalcanto (group B), and Klekamp (group C) were applied in 24 cervical specimens. The facet fractures, the encroachment of the cervical anterior branches of nerve roots and vertebral arteries and the failure of the screws to go through the facets were observed and analyzed. Results. One hundred ninety-two transarticular screws were implanted on both sides in 24 cervical cadavers, 64 for each group. There were 25 splits of inferior facets in group B, 2 splits in group C, and none in group A. Thirty-six screws encroached the vertebral arteries in group A, none in groups B and C. Forty anterior branches of lower cervical nerve roots were involved in group A, 5 in group B, and 3 in group C. Although all screws went through facets in the study except for 5 in group A, there were no significant differences between each group (&khgr;AB2 = 3.33, P > 0.05; &khgr;AC2 = 3.33, P > 0.05). Conclusion. There is a high risk of injury to the anterior branch of the cervical nerve roots and vertebral artery if the screws were too long, and the Takayasu technique was used. However, the rate of facet splitting is high if the Dalcanto technique was applied. Klekamps technique is recommended.

Results of a modified posterolateral approach for the isolated posterolateral tibial plateau fracture

Background: There are few posterolateral approaches that do not require the common peroneal nerve (CPN) dissection. With the nerve exposure, it would pose a great challenge and sometimes iatrogenic damage over the surgical course. The purpose was to present a case series of patients with posterolateral tibial plateau fractures treated by direct exposure and plate fixation through a modified posterolateral approach without exposing the common peroneal nerve (CPN). Materials and Methods: 9 consecutive cases of isolated posterior fractures of the posterolateral tibial plateau were operated by open reduction and plate fixation through the modified posterolateral approach without exposing the CPN between June 2009 and January 2012. Articular reduction quality was assessment according to the immediate postoperative radiographs. At 24 month followup, all patients had radiographs and were asked to complete a validated outcome measure and the modified Hospital for Special Surgery (HSS) Knee Scale. Results: All patients were followedup, with a mean period of 29 months (range 25–40 months). Bony union was achieved in all patients. In six cases, the reduction was graded as best and in three cases the reduction was graded as middle according to the immediate postoperative radiographs by the rank order system. The average range of motion arc was 127° (range 110°–134°) and the mean postoperative HSS was 93 (range 85–97) at 24 months followup. None of the patients sustained neurovascular complication. Conclusions: The modified posterolateral approach through a long skin incision without exposing the CPN could help to expand the surgical options for an optimal treatment of this kind of fracture, and plating of posterolateral tibial plateau fractures would result in restoration and maintenance of alignment. This approach demands precise knowledge of the anatomic structures of this region.

Surgical treatment for terrible triad injury of the elbow with anteromedial coronoid fracture through a combined surgical approach

Summary Objective To report the results of the surgical treatment of terrible triad injury with anteromedial coronoid fracture through a combined surgical approach. Methods This retrospective study evaluated data from patients who underwent surgery to repair terrible triad injuries and anteromedial coronoid fractures. Surgical treatment involved radial head repair or replacement, medial and lateral collateral ligament repair, and coronoid fracture fixation through combined approaches. Evaluations were performed using the Mayo Elbow Performance Score (MEPS) and anteroposterior and lateral radiographs of the elbow. Results Twenty-two patients (15 males, seven females; mean ± SD age, 47.5 ± 11.4 years) were enrolled in this study. Fracture union and concentric reduction of both the ulnotrochlear and radiocapitellar articulations were achieved in all patients. The mean ± SD follow-up was 31.6 ± 11.9 months. The mean ± SD arc of flexion–extension was 110.3° ± 26.3° and arc of forearm rotation was 139.5° ± 17.1°. The mean ± SD MEPS was 88.1 ± 12.2 points, with results classified as excellent in eight elbows, good in ten, and fair in four. Six patients had radiographic signs of post-traumatic arthritis. Three patients required secondary surgeries. Conclusion Combined surgical approaches can be considered for the treatment of terrible triad injuries in association with anteromedial coronoid fractures.

Clinical application of combined fixation in the cervical spine using posterior transfacet screws and pedicle screws.

The aim of the present study was to describe the clinical application of combined fixation in the cervical spine using posterior transfacet and pedicle screws. Ten patients with cervical disorders requiring stabilization were treated from May 2006 to December 2008. The operative details varied depending on indication, the need for decompression, and the number of levels to be included in the spinal construct. Radiographic analysis of the fusion was performed after surgery. A total of 23 transfacet screws were inserted at or caudal to the C4/5 facet. A total of 21 pedicle screws were placed. All patients underwent operative treatment without neurovascular complications. Fusion was achieved in all patients. When performed appropriately, the method of using posterior transfacet screws in the caudal cervical joints combined with pedicle screw fixation in the cephalic cervical spine is reliable and deserves more widespread use.