Posterior Fixation Techniques Research Articles

A novel technique for C1-C2 posterior screw insertion using patient-specific guides created by CT-based 3D printing.

C1-C2 fixation has been developed for the rigid fusion of atlantoaxial instability. C1 lateral mass screw (C1 LMS)-C2 pedicle screw fixation is used more frequently due to its rigid fixation and high bone fusion rate. However, C1 screw placement is relatively unsafe even with recently developed image-based navigation systems. Patient-specific screw guide templates (PSGT) were developed to improve the accuracy and safety of C1 screw placement. Herein, we investigated the outcomes of the C1-C2 posterior fixation technique using PSGT. This was a retrospective study of six patients who underwent posterior cervical spinal fusion using the PSGT between January 2022 and April 2023. Operative time, estimated blood loss, intraoperative radiation dose, surgical cost, and screw placement accuracy were evaluated and compared with those achieved with preoperative CT-based navigation (navigation group, n = 15). Screw accuracy was assessed using Neo's classification. PSGT showed good results, although the differences were not statistically significant (operation time: 104.3 ± 9.7 min vs 116.4 ± 20.8 min; estimated blood loss: 56.7 ± 72.4 mL vs 123.2 ± 162.3 mL; and radiation dose: 1.8 ± 1.2 mSv vs 2.6 ± 0.8 mSv, respectively). PSGT was particularly better in terms of the accuracy of C1 LMS (PSGT: 100%, navigation: 83.3%). The deviation at the entry point was minimal, and the difference between the sagittal and transversal angles from the preoperative plan was small. We investigated the clinical efficacy of using the PSGT for C1-C2 posterior fixation. PSGT improved the accuracy of C1 LMS insertion.

Biomechanical Effect of Different Posterior Fixation Techniques on Stability and Adjacent Segment Degeneration in Treating Thoracolumbar Burst Fracture With Osteoporosis: A Finite Element Analysis.

Finite element analysis. To investigate the biomechanical effect of four posterior fixation techniques on stability and adjacent segment degeneration in treating thoracolumbar burst fractures with osteoporosis. In terms of stability and adjacent segment degeneration, there remains no consensus or guidelines on the optimal technique for the treatment of thoracolumbar burst fractures in patients with osteoporosis. Images of CT scans were imported into MIMICS and further processed by Geomagic to build three-dimensional models of the T10-L5 region. A v-shaped osteotomy was performed on the L1 vertebral body to simulate a burst fracture in the setting of osteoporosis. Subsequently, four fixation techniques were designed using SolidWorks software. Range of motion (ROM) of the global spine, ROM distribution, ROM of adjacent segment, Von Mises stress on adjacent intervertebral disks, and facet joints were analyzed. Among the four groups, the cortical bone screw fixation (CBT) showed the highest global ROM at 1.86°, while long-segmented pedicle screw fixation (LSPS) had the lowest global ROM at 1.25°. The LSPS had the smallest percentage of ROM of fractured vertebral body to fixed segment at 75.04%, suggesting the highest stability after fixation. The maximum ROM of the adjacent segment was observed in the CBT at 1.32°, while the LSPS exhibited the smallest at 0.89°. However, the LSPS group experienced larger maximum stress on the adjacent intervertebral disks (9.60MPa) and facet joints (3.36MPa), indicating an increasing risk of adjacent segment disease. LSPS provided the greatest stability, while CBT provided the smallest amount of stability. However, the elevated stress on adjacent intervertebral disks and facet joints after LSPS fixation increased the possibility of adjacent segment degeneration. Cement-augmented pedicle screw fixation (CAPS) and combined cortical bone screw and pedicle screw fixation (CBT-PS) demonstrated significant biomechanical advantages in providing moderate fixation strength while reducing stress on the intervertebral disks and facet joints.

Posterior atlantoaxial fixation of osteoporotic odontoid fracture: biomechanical analysis of the Magerl versus harms techniques in a cadaver model

BACKGROUND CONTEXTOdontoid fractures are among the most common cervical spine fractures in the elderly and are associated with increased morbidity and mortality. Clinical evidence suggests improved survival and quality of life after operative intervention compared to nonoperative treatment. PURPOSEThis study seeks to examine the stability of an osteoporotic Type II odontoid fracture following posterior atlantoaxial fixation with either the Magerl transarticular fixation technique or the Harms C1 lateral mass screws C2 pedicle screw rod fixation. STUDY DESIGNBiomechanical cadaveric study. METHODSEighteen cadaveric specimens extending from the cephalus to C7 were used in this study. Reflective marker arrays were attached to C1 and C2 and a single marker on the dens to measure movement of each during loading with C2–C3 and occiput-C1 being allowed to move freely. A biomechanical testing protocol imparted moments in flexion-extension, axial rotation, and lateral bending while a motion capture system recorded the motions of C1, C2, and the dens. The spines were instrumented with either the Harms fixation (n=9) or Magerl fixation (n=9) techniques, and a simulated Type II odontoid fracture was created. Motions of each instrumented spine were recorded for all moments, and then again after the instrumentation was removed to model the injured, noninstrumented state. RESULTSBoth Harms and Magerl posterior C1–C2 fixation allowed for C1, C2, and the dens to move as a relative unit. Without fixation the dens motion was coupled with C1. No significant differences were found in X, Y, Z translation motion of the dens, C1 or C2 during neutral zone motions between the Magerl and Harms fixation techniques. There were no significant differences found in Euler angle motion between the two techniques in either flexion-extension, axial rotation, or lateral bending motion. CONCLUSIONSOur findings suggest that both Harms and Magerl fixation can significantly reduce dens motion in Type II odontoid fractures in an osteoporotic cadaveric bone model. CLINICAL SIGNIFICANCEBoth Harms and Magerl posterior atlantoaxial fixation techniques allowed for C1, C2, and the dens to move as a relative unit following odontoid fracture, establishing more anatomic stability to the upper cervical spine.

OLIF联合后路经皮椎弓根螺钉内固定技术与传统TLIF治疗腰椎滑脱症的近期疗效对比

OLIF联合后路经皮椎弓根螺钉内固定技术与传统TLIF治疗腰椎滑脱症的近期疗效对比

Comparison of Staple, Anchor, and Tenodesis Screw for Posterior Tibialis Tendon Fixation: A Biomechanical Analysis

Various posterior tibialis tendon fixation techniques are described in literature. Suture anchor, staple and tenodesis screws are widely used for posterior tibialis tendon transfer, but their stiffness and the maximal ultimate failure load were not tested before. We aimed to compare the initial ultimate failure load and stiffnesses of suture anchor, staple and tenodesis screws on bovine tendon fixation to bovine metaphyseal bone. Thirty-five fresh bovine ankle joints and hooves were obtained from a local abattoir. Metatarsals bones with long extensor tendons were harvested. Staple group had 15, suture anchor group had 10, and tenodesis screw group had 10 samples. All fixations were tested with Instron® ElectroPuls® E10000 Test Instrument. Ultimate failure load and failure location were noted. Staple group's median ultimate failure load was 210.03 N (IQR: 133.43), suture anchor group's was 124.33 N (IQR: 63.67), and tenodesis screw group's was 394.46 N (IQR:115.09). Median stiffness of the staple group was 19.87 N/m (IQR: 15.29); the tenodesis screw group's was 20.28 N/m (IQR: 6.18), the anchor group's was 8.54 N/m (IQR: 4.35). Staples' failure occurred on tendon-staple interface, while suture anchors' occurred on anchor-suture interface and tenodesis screws' occurred on tendon-suture interface. Tenodesis screws' ultimate failure load was the highest (tenodesis vs anchor and staple p < .001 and p=.032, respectively). Staple fixation is less expensive than the other methods and can provide sufficient fixation strength but was weaker than the tenodesis screw fixation. Staples are still a good choice for tendon to bone fixation, whereas the suture anchors provide lower fixation strength at a higher cost.

Biomechanical evaluation of different posterior fixation techniques for treating thoracolumbar burst fractures of osteoporosis old patients: a finite element analysis.

Objective: To investigate the biomechanical characteristics of different posterior fixation techniques in treatment of osteoporotic thoracolumbar burst fractures by finite element analysis. Methods: The Dicom format images of T10-L5 segments were obtained from CT scanning of a volunteer, and transferred to the Geomagic Studio software, which was used to build digital models. L1 osteoporotic burst fracture and different posterior fixation techniques were simulated by SolidWorks software. The data of ROM, the maximum displacement of fixed segment, ROM of fractured L1 vertebrae, the stress on the screws and rods as well as on fractured L1 vertebrae under different movement conditions were collected and analysed by finite element analysis. Results: Among the four groups, the largest ROM of fixed segment, the maximum displacement of fixed segment and ROM of fractured vertebrae occurred in CBT, and the corresponding data was 1.3°, 2.57mm and 1.37°, respectively. While the smallest ROM of fixed segment, the maximum displacement of fixed segment and ROM of fractured vertebrae was found in LSPS, and the corresponding data was 0.92°, 2.46mm and 0.89°, respectively. The largest stress of screws was 390.97Mpa, appeared in CBT, and the largest stress of rods was 84.68MPa, appeared in LSPS. The stress concentrated at the junction area between the root screws and rods. The maximum stress on fractured vertebrae was 93.25MPa, appeared in CBT and the minimum stress was 56.68MPa, appeared in CAPS. And the stress of fractured vertebrae concentrated in the middle and posterior column of the fixed segment, especially in the posterior edge of the superior endplate. Conclusion: In this study, long-segment posterior fixation (LSPF) provided with the greatest stability of fixed segment after fixation, while cortical bone screw fixation (CBT) provided with the smallest stability. Cement-augmented pedicle screw-rod fixation (CAPS) and combined using cortical bone screw and pedicle screw fixation (CBT-PS) provided with the moderate stability. CBT-PS exhibited superiority in resistance of rotational torsion for using multiple connecting rods. CAPS and CBT-PS maybe biomechanically superior options for the surgical treatment of burst TL fractures in osteoporotic patients.

Posterior Spinal Screw Fixation Techniques and Trajectories: General Overview and an Analysis of How Often They Are Used

Abstract Background: There is a great variety of techniques (translaminar, transfacet, and extrapedicular screws) apart from the traditional pedicle screw in posterior spinal instrumentation. The latter technique is the most widely used around the world (except from the cervical region) since it tends to obtain very good results with a simple approach with fewer complications.Therefore, other trajectories are usually reserved for more specific cases in which the insertion of these purely pedicle screws is not possible. Objective: The objective of this study was to review and analyze the use of different techniques and trajectories of posterior spinal instrumentation by different spinal surgeons around the world. Material and Methods: We developed a survey including posterior spinal screw techniques and trajectories. In this article, we present the data resulting from 122 answers from different spinal surgeons (neuro, orthopedic surgery). Results: Despite advances in the development of new technologies such as neuronavigation (17%) and robotic (1%) available on the market, nowadays, the gold-standard technique for spinal screw insertion is the fluoroscopy-assisted freehand approach (54%). The lumbar spine is the most instrumented spinal region (31%), with a clear preference for purely transpedicular screws. Thoracic and sacroiliac areas presented a greater diversity of screw trajectories. In the cervical spine, there is a clear tendency toward the insertion of lateral mass screws (85% in the atlantoaxial region and 70% in the subaxial region), as opposed to the use of pedicular screws. This is mainly due to the complexity of this area and the risk of damaging important neurovascular structures relatively close to the pedicles. Unexpectedly, two additional techniques were presented: cortical bone trajectory for lumbar screw fixation (for osteoporotic patients) and S2-alar-iliac screw fixation (more used than iliac screws alone). Conclusions: This survey demonstrates that the most used spinal trajectory in the thoracolumbar spinal region is the traditional pedicle screw insertion. Lateral mass was the most common place to insert screws in the subaxial cervical region. The use of robotic systems can improve the position of the screws of more complex techniques. We consider that the different techniques should be known since every surgery will be adapted to the patient’s anatomy and needs.

Stress analysis of the screw of atlantoaxial posterior screw fixation C1LM-C2PS and C1LM-C2PARS with and without rod: A FEM based study

Human cervical spine consists of three vertebrae C0-occiput, C1-atlas, & C3-axial in its upper part. The atlantoaxial complex is the most portable segment of the cervical spine and is accountable for half of the flexion, extension, and axial rotation movements of the neck. Atlantoaxial cervical spine injuries are serious injuries since there is a likely risk of harm to the spinal cord. Sustaining stability of the atlantoaxial joint following a neck injury is a difficult task because both vertebrae have complicated anatomy. Thus, the strength of a bone screw is especially significant in the early post-operative stages. Different stabilization procedures have been accounted for C1-C2 injury fixation, out of which fixation with transarticular screws is considered as the gold standard procedure. But screw malposition and high riding transverse foramen of the C2 vertebra are some limitations of this fixation technique. Current FE-based study provides a comparison of the biomechanical stability of the two different atlantoaxial posterior screw fixation techniques (C1Lateral Mass-C2 Pedicle screws, C1Lateral Mass-C2PARS screws).In this work, a C1-C2 cervical spine model of a male patient is developed using MRI CT scan data using a 3-d slicer software and biomechanical stability comparison is done for C1LM-C2PS & C1LM-C2PARS screws fixed once with a supporting posterior screw fixation rod and once without rod under the physiological loading conditions of flexion, extension, lateral bending, and axial rotation using ANSYS WORKBENCH 16.2. The effects of the engaging supporting rod on the cervical spine were evaluated in the form of von-mises stresses induced in screws. Result shows reduction in screw stress values when implanted with supporting rods. C1LM-C2PS screw fixation with rod might be thought of as the best fixation solution for fractured C1-C2 vertebrae as it showed minimum stress values in the analysis as compared to C1LM-C2PARS with and without rod.

Traumatic atlantoaxial dislocation with a type III odontoid fracture: a rare and fatal injury

Traumatic atlantoaxial dislocation with a dens fracture is very rare in children. In this case report, a 15-year-old woman presented at the emergency department after being hit by a motor vehicle as a bicyclist. CT scans showed a type III dens fracture with retropulsion of the posterior wall, resulting in significant stenosis of the spinal canal. A cervical transection and prevertebral hematoma were present. External immobilization can be applied conservatively. However, atlantoaxial dislocation may require surgical fixation to stabilize and prevent slippage. Here, posterior screw-rod fixation techniques can provide better results in terms of neurological outcomes, pain status and adverse events compared to other techniques. However, head and neck imaging should be performed to consider surgical intervention.

Intra-articular Distraction Versus Decompression to Treat Basilar Invagination Without Atlantoaxial Dislocation: A Retrospective Cohort Study of 54 Patients.

The surgical management of basilar invagination without atlantoaxial dislocation (type B basilar invagination) remains controversial. Hence, we have reported the use of posterior intra-articular C1-2 facet distraction, fixation, and cantilever technique versus foramen magnum decompression in treating type B basilar invagination as well as the results and surgical indications for this procedure. This was a single-center retrospective cohort study. Fifty-four patients who underwent intra-articular distraction, fixation, and cantilever reduction (experimental group) and foramen magnum decompression (control group) were enrolled in this study. Distance from odontoid tip to Chamberlain's line, clivus-canal angle, cervicomedullary angle, craniovertebral junction (CVJ) triangle area, width of subarachnoid space and syrinx were used for radiographic assessment. Japanese Orthopedic Association (JOA) scores and 12-item Short Form health survey (SF-12) scores were used for clinical assessment. All patients in the experimental group had a better reduction of basilar invagination and better relief of pressure on nerves. JOA scores and SF-12 scores also had better improvements in the experimental group postoperation. SF-12 score improvement was associated with preoperative CVJ triangle area (Pearson index, 0.515; p = 0.004), cutoff value of 2.00 cm2 indicating the surgical indication of our technique. No severe complications or infections occurred. Posterior intra-articular C1-2 facet distraction, fixation, and cantilever reduction technique is an effective treatment for type B basilar invagination. As various factors involved, other treatment strategies should also be investigated.

Biomechanical properties of different anterior and posterior techniques for atlantoaxial fixation: a finite element analysis

BackgroundMany techniques for atlantoaxial fixation have been developed. However, the biomechanical differences among various atlantoaxial fixation methods remain unclear. This study aimed to evaluate the biomechanical influence of anterior and posterior atlantoaxial fixation techniques on fixed and nonfixed segments.MethodsAn occiput-C7 cervical finite element model was used to construct 6 surgical models including a Harms plate, a transoral atlantoaxial reduction plate (TARP), an anterior transarticular screw (ATS), a Magerl screw, a posterior screw-plate, and a screw-rod system. Range of motion (ROM), facet joint force (FJF), disc stress, screw stress, and bone-screw interface stress were calculated.ResultsThe C1/2 ROMs were relatively small in the ATS and Magerl screw models under all loading directions except for extension (0.1°–1.0°). The posterior screw-plate system and screw-rod system generated greater stresses on the screws (77.6–1018.1 MPa) and bone-screw interfaces (58.3–499.0 MPa). The Harms plate and TARP models had relatively small ROMs (3.2°–17.6°), disc stress (1.3–7.6 MPa), and FJF (3.3–106.8 N) at the nonfixed segments. Changes in disc stress and FJF of the cervical segments were not consistent with changes in ROM.ConclusionsATS and Magerl screws may provide good atlantoaxial stability. The posterior screw-rod system and screw-plate system may have higher risks of screw loosening and breakage. The Harms plate and TARP model may more effectively relieve nonfixed segment degeneration than other techniques. The C0/1 or C2/3 segment may not be more susceptible to degeneration than other nonfixed segments after C1/2 fixation.

Anterior atlanto-occipital transarticular screw fixation: a biomechanical comparison with posterior fixation techniques.

Atlanto-occipital instability is commonly treated with posterior fixation. However, in patients with congenital or acquired factors, posterior fixation may not be possible. For these situations, a novel anterior atlanto-occipital transarticular screw (AATS) fixation technique has been introduced recently. However, biomechanical study of this technique is lacking. This study was designed to evaluate the biomechanical stability of AATS fixation for the atlanto-occipital joint and compare it with conventional posterior occipitocervical fixation (POCF). Six cadaveric specimens (occiput-C4) were tested in four conditions, including intact, injury, injury + AATS, and injury + POCF states. A pure moment of 1.5 Nm was applied to specimens in flexion, extension, lateral bending, and axial rotation. The range of motion (ROM) and neutral zone (NZ) were calculated and compared from the occiput to C1. The AATS fixation constrained ROMs to 0.4° in flexion (p < 0.001), 0.4° in extension (p < 0.001), 1.0° in lateral bending (p < 0.001), and 0.7° in axial rotation (p < 0.001) when compared with the injury state. In all directions, there was no statistically significant difference observed in ROMs and NZs between AATS fixation and POCF (p > 0.05). This study identified that the novel AATS fixation, as stand-alone anterior fixation, was equivalent to POCF in all directions. The results suggest that anterior transarticular screw fixation is a biomechanically effective salvage technique for posterior atlanto-occipital fixation, and may also serve as supplemental fixation.

Salvage posterior atlantoaxial fixation techniques: A retrospective study

ObjectSince the atlantoaxial region have critical neurovascular anatomy and limited bone surface for fusion, the application and choice of salvage fixation techniques are highly important. To discuss alternative posterior atlantoaxial fixation surgery techniques. MethodsWe retrospectively surgical records of 22 patients that posterior atlantoaxial fixation techniques were applied. ResultsThe patients included 11 males and 11 females (mean age: 65.7 years). The fracture type that caused instability is type 2 odontoid fractures (22). In six of these patients alternative stabilization techniques were applied due to anatomical variations, huge venous bleeding and iatrogenic trauma of the screw entry points during surgery. ConclusionsOwing to anatomical variations, intraoperative challenges, and/or instrumentation failures, performing alternative surgical fixation technique is an important factor that affects the success of stabilization of the atlantoaxial region. Knowledge of salvage techniques especially during the learning curve is vitally important. Surgeons should adapt to intraoperative surgical challenges as required.

Arthroscopic Reduction and Internal Fixation of Talus Fractures: An All-Inside Soft-Tissue Preserving Technique

Category: Arthroscopy; Hindfoot; Trauma Introduction/Purpose: Talus fractures, although rare, can lead to devastating complications of posttraumatic osteoarthritis (PTA), mal-union, non-unions, and avascular necrosis (AVN). The timing and method of fixation has been controversial, especially for open and extruded fractures. The purpose of this study is to present short-term outcomes using a posterior talus arthroscopic reduction internal fixation (TARIF) technique. The authors hypothesized that talus fractures reduced arthroscopically and fixed percutaneously would have similar outcomes with reduced overall complications compared to traditional open techniques. Methods: We performed a retrospective study on 14 consecutive patients undergoing primary posterior arthroscopic reduction internal fixation for talus fractures from August 2020 to January 2021. All cases were performed completely arthroscopically, utilizing a posterior approach and cannulated screws. Patient demographics, fracture pattern, perioperative complications, and radiographic findings were collected. Results: The mean age of our cohort was 37.3 years (range, 19-75), including 8 males and 6 females, with 58% utilizing nicotine. Motor vehicle accidents accounted for 64% of injuries, followed by falls and gunshot wounds. Fracture location included 9 body fractures, 5 neck fractures Hawkins type 2 (1), 3 (3), and 4 (1). Five fractures were open injuries, 2 of which had vascular injuries that underwent irrigation and debridement followed by external fixation. Intraoperatively, all patients had 2-3 anterior to posterior 3.5mm cannulated headless screws placed with a mean tourniquet time of 87 minutes (range, 0 - 88). Postoperatively, all fractures had the articular surface restored to within 2mm on radiographs. No patients required antibiotics and no debridement's were performed. No acute AVN has been recorded. Conclusion: Our short-term results indicate posterior arthroscopic reduction internal fixation of talus fractures is safe and able to restore the articular surfaces. It also suggests that an all-inside soft tissue preserving technique may reduce short term complications.

Comparison of the Safety and Efficacy of Three-Dimensional Guiding Templates and Free Hand Technique for Cervical Pedicle Screw Fixation: A Retrospective Study

Aim. To compare the safety and efficacy of computed tomography (CT)-assisted three-dimensional guiding templates (3DGTs) and free-hand (FH) technique for posterior cervical pedicle screw fixation in cervical spondylotic myelopathy (CSM) treatment. Methods. Thirty-five patients (216 screws) with CSM and developmental cervical stenosis were randomly divided into groups A (FH) and B (3DGTs). All patients underwent modified posterior surgery with cervical pedicle screw insertion (C1-7). Preoperative, postoperative, and intergroup comparisons of efficacy were evaluated using the visual analog scale (VAS), Japanese Orthopaedic Association (JOA), and Short Form 12 (SF-12) scores and JOA score improvement rate. Incidence of intra- and postoperative complications was analyzed. Postoperative cervical spine CT was performed to evaluate (i) the pedicle screws' deviation angle from the optimal path (sagittal deviation, α; coronal deviation angle, β), screw insertion point's deviation distance (d), and screw accuracy and (ii) the deviation angle and distance of screw entrance point of pedicle screws from the optimal channel. Results. All patients successfully completed the procedures. Groups A and B did not significantly differ in age, sex ratio, body mass index, operative time, or intraoperative blood loss amount. Postoperative VAS, JOA, and SF-12 scores improved in both groups. VAS, JOA, or SF-12 scores did not significantly differ between the 2 groups. The α, β, and d scores were lower in group B, but accuracy was higher in group B. Conclusions. 3DGTs and FH technique show comparable outcomes with respect to neurological improvement and safety.

Accuracy and Safety of Robot-Assisted versus Fluoroscopy-Guided Posterior C1 Lateral Mass and C2 Pedicle Screw Internal Fixation for Atlantoaxial Dislocation: A Preliminary Study.

Objective To compare the accuracy, efficiency, and safety of robotic assistance (RA) and conventional fluoroscopy guidance for the placement of C1 lateral mass and C2 pedicle screws in posterior atlantoaxial fusion. Methods The data of patients who underwent posterior C1–C2 screw fixation (Goel-Harm's technique) in our hospital from August 2014 to March 2021 were retrospectively evaluated, including 14 cases under fluoroscopic guidance and 11 cases under RA. The hospital records, radiographic results, surgical data, and follow-up records were reviewed. Accuracy of screw placement was assessed using the Gertzbein and Robbins scale, and clinical outcomes were evaluated by Japanese Orthopedic Association (JOA) score, visual analogue scale (VAS), modified MacNab criteria, and postoperative complications. Results Baseline characteristics of both groups were similar. The mean estimated blood loss in the fluoroscopic guidance and RA groups was 205.7 ± 80.3 mL and 120.9 ± 31.9 mL, respectively (p = 0.03). The mean surgical duration was 34 min longer with RA compared to that performed with free-hand (FH) method (p = 0.15). In addition, lower intraoperative radiation exposure was detected in the RA group (12.4 ± 1.4 mGy/screw) versus the FH (19.9 ± 2.1 mGy/screw) group (p = 0.01). The proportion of “clinically acceptable” screws (graded 0 and I) was higher in the RA group (93.2%) than that in the FH group (87.5%, p = 0.04). There was no significant difference in the increase of JOA score and decrease of VAS score between the two surgical procedures. Furthermore, there were no significant differences in overall clinical outcome between the two groups and no neurovascular complications associated with screw insertion. Conclusions RA is a safe and potentially more accurate alternative to the conventional fluoroscopic-guided FH technique for posterior atlantoaxial internal fixation.

Perioperative and Radiographic Outcomes Between Single-Position Surgery (Lateral Decubitus) and Dual-Position Surgery for Lateral Lumbar Interbody Fusion and Percutaneous Pedicle Screw Fixation: Meta-Analysis

Lateral lumbar interbody fusion (LLIF) and percutaneous posterior screw fixation (PPSF) techniques is used to treat degenerative lumbar pathologies. Dual-position (DP) lumbar surgery involves repositioning the patient from the supine or lateral decubitus position to prone for posterior fixation. Single-position (SP) lumbar surgery is commonly performed nowadays, a minimally invasive alternative performed entirely from the lateral decubitus position. However, controversy still exists. This meta-analysis aimed to compare perioperative outcomes between SP lumbar surgery and DP lumbar surgery for LLIF and PPSF. We conducted this meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and searched Medline and Scopus from inception to November 11, 2021, for relevant studies. Six studies were identified, which contained totals of 502 and 447 patients in the SP and DP groups, respectively. The unstandardized mean difference in operative time, length of hospital stay, intraoperative blood loss, radiation doses, lumbar lordosis, and pelvic incidence-lumbar lordosis mismatch were -86.1 (95% confidence interval [CI] -149.2 to -23.1) minutes, -1.6 (95% CI -2.4 to -0.9) days, -55.6 (95% CI -127.5 to 16.2) mL, -30.3 (95% CI -80.5 to 19.8) mGy, 1.34 (95% CI -1.17 to 3.86) degrees, and -4.06 (95% CI -5.65 to -2.47) lower in SP when compared with DP. The chances of having complications and reoperations in SP were 0.75 (95% CI 0.49-1.14) and 0.77 (95% CI 0.44-1.36) times, respectively, compared with the DP group. No significant differences were found for intraoperative blood loss, radiation dose, lumbar lordosis, complications, and reoperations between the 2 groups. This meta-analysis found that SP have lower operative time and length of hospital stay compared with DP LLIF and PPSF. However, no differences in intraoperative blood loss, radiation dose, radiographic change, complications, and reoperation rates were found.

Percutaneous cortical bone trajectory screw fixation versus traditional open pedicle screw fixation for type A thoracolumbar fractures without neurological deficit.

Retrospective matched-cohort comparative study. Cortical bone trajectory screw (CBT) technique is a new insertion technique in terms of fixation strength and less invasiveness. The purposes of this study were to compare the clinical and radiological outcomes of percutaneous CBT fixation (PCBT) with traditional open posterior pedicle screw fixation (OPPS) technique. Between September 2019 and October 2020, patients undergoing posterior stabilization were matched for age, sex, diagnosis, fractured level, and AO classification. 24 control patients with OPPS were identified and appropriately matched to 24 consecutive patients with PCBT technique. Clinical outcomes and radiographic assessments including vertebral wedge angle (VWA) and sagittal index were recorded and compared between the two groups. Incision length, intraoperative blood loss and hospital stay in the PCBT group were significantly better than the OPPS group (P < 0.05). The VAS scores 5days after operation for PCBT patients were significantly lower than those for OPPS patients (P = 0.003), but these differences lost significance at last follow-up. There was no significant difference in VWA and sagittal index between OPPS and PCBT group (P > 0.05). While no complications were noted in the PCBT group, there were four cases with complications in the traditional OPPS group. The present study showed that PCBT is a safe and feasible method for the treatment of thoracolumbar fractures without neurological deficits. This new surgical treatment was more minimally invasive, yet yielded equivalent or superior clinical and radiographic outcomes compared to the traditional open pedicle screw fixation surgery.

Postoperative spinal alignment comparison of lateral versus supine patient position L5-S1 anterior lumbar interbody fusion.

Over the past decade, alternative patient positions for the treatment of the anterior lumbar spine have been explored in an effort to maximize the benefits of direct anterior column access while minimizing the inefficiencies of single or multiple intraoperative patient repositionings. The lateral technique allows for access from L1 to L5 through a retroperitoneal, muscle-splitting, transpsoas approach with placement of a large intervertebral spacer than can reliably improve segmental lordosis, though its inability to be used at L5-S1 limits its overall adoption, as L5-S1 is one of the most common levels treated and where high levels of lordosis are optimal. Recent developments in instrumentation and techniques for lateral-position treatment of the L5-S1 level with a modified anterior lumbar interbody fusion (ALIF) approach have expanded the lateral position to L5-S1, though the positional effect on L5-S1 lordosis is heretofore unreported. The purpose of this study was to compare local and regional alignment differences between ALIFs performed with the patient in the lateral (L-ALIF) versus supine position (S-ALIF). Retrospective, multi-center data and radiographs were collected from 476 consecutive patients who underwent L5-S1 L-ALIF (n = 316) or S-ALIF (n = 160) for degenerative lumbar conditions. Patients treated at L4-5 and above with other single-position interbody fusion and posterior fixation techniques were included in the analysis. Baseline patient characteristics were similar between the groups, though L-ALIF patients were slightly older (58 vs. 54years), with a greater preoperative mean L5-S1 disk height (7.8 vs. 5.8mm), and with less preoperative slip (6.6 vs. 8.5mm), respectively. 262 patients were treated with only L-ALIF or S-ALIF at L5-S1 while the remaining 214 patients were treated with either L-ALIF or S-ALIF at L5-S1 along with fusions at other thoracolumbar levels. Lumbar lordosis (LL), L5-S1 segmental lordosis, L5-S1 disk space height, and slip reduction in L5-S1 spondylolisthesis were measured on preoperative and postoperative lateral X-ray images. LL was only compared between single-level ALIFs, given the variability of other procedures performed at the levels above L5-S1. Mean pre- to postoperative L5-S1 segmental lordosis improved 39% (6.6°) and 31% (4.9°) in the L-ALIF and S-ALIF groups, respectively (p = 0.063). Mean L5-S1 disk height increased by 6.5mm (89%) in the L-ALIF and 6.4mm (110%) in the S-ALIF cohorts, (p = 0.650). Spondylolisthesis, in those patients with a preoperative slip, average reduction in the L-ALIF group was 1.5mm and 2.2mm in the S-ALIF group (p = 0.175). In patients treated only at L5-S1 with ALIF, mean segmental alignment improved significantly more in the L-ALIF compared to the S-ALIF cohort (7.8 vs. 5.4°, p = 0.035), while lumbar lordosis increased 4.1° and 3.6° in the respective groups (p = 0.648). Use of the lateral patient position for L5-S1 ALIF, compared to traditional supine L5-S1 ALIF, resulted in at least equivalent alignment and radiographic outcomes, with significantly greater improvement in segmental lordosis in patients treated only at L5-S1. These data, from the largest lateral ALIF dataset reported to date, suggest that-radiographically-the lateral patient position can be considered as an alternative to traditional ALIF positional techniques.

An experience with Goel-Harms C1-C2 fixation for type II odontoid fractures.

ABSTRACTObjective:Type II odontoid fractures need surgical stabilization for disabling neck pain and instability. Anterior odontoid screw fixation is a well-known technique. However, certain patients require posterior fixation. We present our surgical results and experiences with nine cases managed by the Goel-Harms technique.Materials and Methods:This is a retrospective review of nine patients operated on between January 2019 and December 2021 for Type II odontoid fractures with posterior fixation technique. Their clinical profile was collected from case files. The radiological data were retrieved from radiology archives. The indications for surgery were instability and refractory neck pain. The surgical decision for posterior fixation was guided by fracture morphology.Results:The mean age of presentation was 37.22 ± 9.85 years. Seven patients had Type II, and two had Type IIa odontoid fracture. All patients presented with unbearable neck pain. One patient had a quadriparesis. The fracture line was anterior-inferior sloping in six, posterior-inferior sloping in two, and transverse in one case. The anterior-posterior displacement of fracture ranged from 0 to 7 mm (mean 2.44 ± 2.18 mm). Partial transverse ligament tear without the Atlanto Axial Dislocation was present in three patients. The C1-C2 joint distraction was required in five cases. C1-C2 joint spacer was required in two cases. Following surgery, neck pain was relieved in all cases. Complete fracture alignment was achieved in eight patients. There were no postoperative complications. At the mean follow-up of 16.22 ± 9.61 months, there was no implant failure.Conclusions:Posterior C1-C2 fixation by the Goel-Harms technique is an excellent alternative to anterior fixation in selected cases.