Unilateral Fixation Research Articles

Comparison of clinical and radiographic outcomes of bilateral versus unilateral ramus fixation in straddle fractures with posterior pelvic ring injury.

Superior and inferior ramus fractures, termed straddle fractures, are high-energy fractures often accompanied by unstable pelvic ring injuries. However, consensus is lacking regarding indications for surgical treatment or fixation methods. We aimed to compare clinical and radiological outcomes of unilateral ramus fixation (URF) and bilateral ramus fixation (BRF) for straddle fractures with unilateral posterior pelvic ring injuries. We enrolled 118 patients (73 males, 45 females; mean age, 47 years) diagnosed with straddle fractures between March 2015 and December 2021 with > 1 year of follow-up. Patients were divided into URF (n = 60) and BRF (n = 58) groups based on the anterior pelvic ring fixation method. Preoperative factors including body mass index, diabetes, smoking, injury mechanism, injury severity score, American Society of Anesthesiologists classification system, Tile classification, and Young and Burgess classification were compared. Intraoperative blood loss, operation time, postoperative bone union rate, complications, and the need for additional surgeries were analyzed. There were no statistically significant preoperative differences between the two groups. However, the URF group showed a significantly lower mean operative time and blood transfusion requirement (63min and 2 units, respectively) than the BRF group (104min and 3 units, respectively) (both p < 0.001). Postoperatively, bone union was achieved in 57 (95.0%) and 56 (96.6%) patients in the URF and BRF groups, respectively. Complications occurred in 17 (28.3%) and 14 (24.1%) patients in the URF and BRF groups, respectively, with additional surgeries needed in 3 (5.0%) patients in the URF group and 2 (3.4%) patients in the BRF group. Unilateral anterior fixation can provide sufficient stability and clinical effectiveness in the surgical treatment of straddle fractures in areas with posterior pelvic ring injuries. Compared with bilateral anterior fixation, unilateral fixation significantly reduces operation time and blood loss, making it a viable fixation method for straddle fractures.

The comparison study of laminectomy with unilateral and bilateral pedicle screws fixation and laminectomy alone without fusion interbody in young patients with lumbar spinal stenosis: A randomized clinical trial

BackgroundThere are many reports about the risk factors for recurrence after laminectomy surgery. Some surgeons use unilateral and bilateral fusion to provide sufficient stability to the lumbar spine. However, its strength, safety, and effectiveness in young patients are not widely known. Therefore, this study was conducted to compare surgical methods of laminectomy with unilateral and bilateral fixation and laminectomy alone without interbody fusion in young patients with lumbar spinal stenosis. Methods90 patients eligible for lumbar spinal stenosis surgery were selected through convenience sampling and randomly divided into three groups: laminectomy without fixation (A), laminectomy with unilateral fixation (B), and bilateral fixation (C). Pain, functional disability, quality of life, recurrent disc, adjacent segment disease (ASD), and fusion rate were evaluated and compared among the three groups six months post-surgery. The data were analyzed using SPSS version 16. ResultsSix months after surgery, the mean score of functional disability in the bilateral group was significantly higher than the other groups (12.92 (3.30) vs 5.52 (1.91) and 4.30 (1.84), P < 0.05). Also, the highest mean score of pain after surgery was observed in the bilateral group (4.33 (0.70) vs 1.81(0.68) and 1.63(0.56), P < 0.05). The mean score of quality of life in the unilateral group was significantly higher than the other groups (87.81 (5.67) vs 68.58 (3.08) and 56.07 (4.04), P < 0.05). No significant difference was observed between the groups (P > 0.05) regarding fusion, recurrent disc herniation, and adjacent segment disease. ConclusionsUnilateral fixation provides the same benefits as bilateral fixation but has the additional benefits of being less invasive and minimizing the disadvantages of other investigated techniques during and after surgery.

P-079 Bilateral versus unilateral orchidopexy: IVF/ICSI-ET outcomes

Abstract Study question Does unilateral and bilateral cryptorchidism infertility have an impact on IVF/ICSI-ET results? Summary answer Unilateral and bilateral orchidopexy do not affect the final live birth rate in IVF. What is known already A study was compared ICSI-ET outcomes between bilateral and unilateral cryptorchidism in NOA patients. Although 90.36% of their study population have undergone orchidopexy to improve their conditions at around 9 to 10 years old, the fertilization rates of bilateral and unilateral cryptorchidism group were only at 46.8% and 46.5% respectively, which were slightly below the average ICSI fertilization rate. The other study showed that patients of bilateral cryptorchidism had lower implantation rate. Apart from the mentioned study, no other study has attempted to evaluate the IVF/ICSI-ET outcomes in infertile men who had undergone orchidopexy. Study design, size, duration A retrospective cohort study at a tertiary hospital, including a total of 99 infertile men who underwent orchidopexy to treat cryptorchidism and subsequently underwent their first IVF/ICSI-ET cycle from January 2014 to January 2022. Participants/materials, setting, methods Men are divided into unilateral fixation group and bilateral fixation group based on the laterality of the cryptorchidism and testicular fixation surgery they have received. Choose fertilization rate and live birth rate as parameters for evaluating the results. Main results and the role of chance The sperm concentration and viability were significantly higher in unilateral orchidopexy group than in bilateral orchidopexy group (28.09 ± 27.99 vs 7.99 ± 14.68, P=0.001; 33.34 ± 22.52 vs 11.95 ± 17.85, P=0.001). Unilateral orchidopexy group showed lower demand for ICSI (66.07% vs 95.35%, P&amp;lt;0.001). Interestingly, both groups exhibited similar rates of fertilization, clinical pregnancy, live birth and birth defect. Boy birth ratio was lower in bilateral orchidopexy group as compared to unilateral orchidopexy group (27.27% vs 58.62%, P=0.026). Limitations, reasons for caution This study was limited in that the data source captured only patients from a single medical center, which could lead to selection bias, small sample size and limited external validity to the findings. Wider implications of the findings Our study suggested that blastocyst-stage ET is a good strategy for patients with history of orchidopexy. Trial registration number not applicable

What's new in pediatric lower limb reconstruction?

The last years brought many advances relevant to lower limb reconstruction. It feels like guided growth has been looked at from every angle, and still there are new emerging concepts like rotational guided growth waiting to be validated. New hexapod external devices are more accurate and easier to use, and new unilateral fixators allow for more versatile and stable fixation and lengthening. Intramedullary nail lengthening has found its place as a standard procedure for various diagnoses in children and young adults. First results of new and exciting approaches like extramedullary implantable nail lengthening and lengthening plates have been reported. Pharmaceutical treatment has changed the course of certain diseases and must be integrated and considered when making a reconstructive treatment plan. As reconstructive surgery is rapidly advancing so are the technical options for prosthetic fitting, which makes it difficult for caregivers as well as for parents to make the decision between reconstruction and amputation surgery for the most severe cases of congenital deficiencies. This review is highlighting new developments of lower limb reconstruction and is reviewing the current literature.

Unilateral external fixator and its biomechanical effects in treating different types of femoral fracture: A finite element study with experimental validated model

Previous works had successfully demonstrated the clinical effectiveness of unilateral external fixator in treating various types of fracture, ranging from the simple type, such as oblique and transverse fractures, to complex fractures. However, literature that investigated its biomechanical analyses to further justify its efficacy is limited. Therefore, this paper aimed to analyse the stability of unilateral external fixator for treating different types of fracture, including the simple oblique, AO32C3 comminuted, and 20 mm gap transverse fracture. These fractures were reconstructed at the distal diaphysis of the femoral bone and computationally analysed through the finite element method under the stance phase condition. Findings showed a decrease in the fixation stiffness in large gap fracture (645.2 Nmm-1 for oblique and comminuted, while 23.4 Nmm-1 for the gap fracture), which resulted in higher displacement, IFM and stress distribution at the pin bone interface. These unfavourable conditions could consequently increase the risk of delayed union, pin loosening and infection, as well as implant failure. Nevertheless, the stress observed on the fracture surfaces was relatively low and in controlled amount, indicating that bone unity is still allowable in all models. Briefly, the unilateral fixation may provide desirable results in smaller fracture gap, but its usage in larger gap fracture might be alarming. These findings could serve as a guide and insight for surgeons and researchers, especially on the biomechanical stability of fixation in different fracture types and how will it affect bone unity.

Unilateral Fixation of the Bony Pyramid in Deviated Nose Correction.

Deviated nose correction is one of the most challenging procedures in rhinoplasty. Recent studies proposed effectiveness of preservation techniques even for patients with crooked nose deformity, although the long-term results are still controversial. Obviously, only addressing the blocking points is not enough to achieve stable midline position in crooked nose. To ensure consistent long-term results, we proposed a unilateral suturing of the bony pyramid along with unilateral resection of the excessive bone along the lateral osteotomy line. The first results of described surgical technique have proven its simplicity, reliability, and high efficiency both in primary and in revision surgeries. LEVEL OF EVIDENCE V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Treatment of Lumbar Degenerative Disease with a Novel Interlaminar Screw Elastic Spacer Technique: A Finite Element Analysis.

A novel interlaminar elastic screw spacer technique was designed to maintain lumbar mobility in treating lumbar degenerative diseases. A validated finite element model of L4/5 was used to establish an ISES-1/2 model and an ISES-1/3 model based on different insertion points, a unilateral fixation model and a bilateral fixed model based on different fixation methods, and a Coflex-F model based on different implants. The elastic rods were used to fix screws. Under the same mechanical conditions, we compared the biomechanical characteristics to investigate the optimal entry point for ISES technology, demonstrate the effectiveness of unilateral fixation, and validate the feasibility of the ISES technique. Compared to ISES-1/3, the ISES-1/2 model had lower intradiscal pressure, facet cartilage stress, and posterior structural stress. Compared to the ISES-BF model, the ISES-UF model had lower intervertebral pressure, larger mobility, and smaller stress on the posterior structures. The ISES model had a similar intervertebral pressure and limitation of extension as the Coflex-F model. The ISES model retained greater mobility and reduced the stress on the facet cartilage and posterior structure compared with the Coflex-F model. Our study suggests that the ISES technique is a promising treatment of lumbar degenerative diseases, especially those with osteoporosis.

Comparison of the clinical efficacy of unilateral and bilateral pedicle screw short-segment fixation and fusion in the treatment of atlantoaxial fracture-dislocation.

Few studies have compared the clinical efficacy of unilateral and bilateral pedicle screw fixation and fusion in treating atlantoaxial fracture-dislocation. To compare the efficacy of unilateral and bilateral fixation and fusion for atlantoaxial fracture-dislocation and to explore the feasibility of the unilateral surgical procedure. Twenty-eight consecutive patients with atlantoaxial fracture-dislocation were included in the study from June 2013 to May 2018. They were divided into a unilateral fixation group and a bilateral fixation group (14 patients in each group with an average age of 43.6 ± 16.3 years and 51.8 ± 15.4 years, respectively). The unilateral group had a unilateral anatomical variation of the pedicle or vertebral artery, or traumatic pedicle destruction. All patients underwent atlantoaxial unilateral or bilateral pedicle screw fixation and fusion. Intraoperative blood loss and operation time were recorded. The visual analog scale (VAS) and Japanese Orthopedic Association (JOA) scoring systems were used to evaluate pre- and postoperative occipital-neck pain and neurological function. X-ray and computerized tomography (CT) were used to assess atlantoaxial stability, the implants' position, and bone graft fusion. All patients were followed up for 39-71 months postoperatively. Intraoperatively, no spinal cord or vertebral artery injury was observed. At the last follow-up, occipital-neck pain and neurological function in the two groups were significantly improved (P< 0.05). The X-ray films and CT showed satisfactory atlantoaxial stability, implant position, and osseous fusion in all the patients at 6 months postoperatively. Unilateral and bilateral pedicle screw fixation and fusion can restore atlantoaxial stability and improve occipital-neck pain and neurological function in patients with atlantoaxial fracture-dislocation. The unilateral surgical procedure can be a supplementary option for patients with unilateral abnormal atlantoaxial lesions.

Mechanical Stability Analysis of the External Unilateral Fixation Device due to the Impact of Axial Pressure

This study performed a mechanical stability analysis for the impact of axial pressure on an Ultra X external unilateral fixation device applied to a tibia with an open fracture. The real construction of the fixation device was used to create a 3D geometric model using a Finite Element Method (FEM) model, which was made to perform structural analysis in the CATIA V5 (Computer Aided Three-dimensional Interactive Application) CAD/CAE system. Specific stresses and displacements were observed at points of interest using structural analysis. The focus was on the relative displacements of the proximal and distal bone segments in the fracture zone. These displacements were used to calculate the stiffnesses of the bone in the fracture zone and the fixation device itself. The results obtained provide the necessary information regarding the stability of the Ultra X fixation device.

Biomechanical evaluation of a novel minimally invasive pedicle bone cement screw applied to the treatment of Kümmel's disease in porcine vertebrae.

Background and objective: Treatment of Kümmel's Disease (KD) with pure percutaneous kyphoplasty carries a greater likelihood of bone cement displacement due to hardened bone and defect of the peripheral cortex. In this study, we designed a novel minimally invasive pedicle bone cement screw and evaluate the effectiveness and safety of this modified surgical instruments in porcine vertebrae. Methods: 18 mature porcine spine specimens were obtained and soaked in 10% formaldehyde solution for 24h. 0.5000mmol/L EDTA-Na2 solution was used to develop in vitro osteoporosis models of porcine vertebrae. They were all made with the bone deficiency at the anterior edge of L1. These specimens were randomly divided into 3 groups for different ways of treatment: Group A: pure percutaneous kyphoplasty (PKP) group; Group B: unilateral novel minimally invasive pedicle bone cement screw fixation combined with PKP group; Group C: bilateral novel minimally invasive pedicle bone cement screw fixation combined with PKP group. The MTS multi-degree of freedom simulation test system was used for biomechanical tests, including axial loading of 500N pressure, range of motion (ROM) in flexion, extension, left/right lateral bending, and left/right axial rotation at 5Nm, and the displacement of bone cement mass at maximum angles of 5° and 10°. Result: The three groups were well filled with bone cement, no leakage or displacement of bone cement was observed, and the height of the vertebrae was higher than pre-operation (p < 0.05). In the left/right axial rotation, the specimens were still significantly different (p < 0.05) from the intact specimens in terms of ROM after PKP. In other directions, ROM of all group had no significant difference (p < 0.05) and was close to the intact vertebrae. Compared with PKP group, the relative displacement of bone cement in groups B and C was smaller (p < 0.05). Conclusion: In the in vitro animal vertebral models, the treatment of KD with the placement of novel pedicle minimally invasive bone cement screw combined with PKP can effectively restore the vertebral height, improve the stability of the affected vertebra and prevent the displacement of bone cement. Biomechanically, there is no significant difference between bilateral and unilateral fixation.

Posterior intra-articular fixation stabilizes both primary and secondary sacroiliac joints: a cadaveric study and comparison to lateral trans-articular fixation literature

BackgroundPosterior and lateral techniques have been described as approaches to sacroiliac joint arthrodesis. The purpose of this study was to compare the stabilizing effects of a novel posterior stabilization implant and technique to a previously published lateral approach in a cadaveric multidirectional bending model. We hypothesized that both approaches would have an equivalent stabilizing effect in flexion–extension and that the posterior approach would exhibit better performance in lateral bending and axial rotation. We further hypothesized that unilateral and bilateral posterior fixation would stabilize both the primary and secondary joints.MethodsRanges of motion (RoMs) of six cadaveric sacroiliac joints were evaluated by an optical tracking system, in a multidirectional flexibility pure moment model, between ± 7.5 N-m applied moment in flexion–extension, lateral bending, and axial rotation under intact, unilateral fixation, and bilateral fixation conditions.ResultsIntact RoMs were equivalent between both samples. For the posterior intra-articular technique, unilateral fixation reduced the RoMs of both primary and secondary joints in all loading planes (flexion–extension RoM by 45%, lateral bending RoM by 47%, and axial RoM by 33%), and bilateral fixation maintained this stabilizing effect in both joints (flexion–extension at 48%, lateral bending at 53%, and axial rotation at 42%). For the lateral trans-articular technique, only bilateral fixation reduced mean RoM of both primary and secondary sacroiliac joints, and only under flexion–extension loads (60%).ConclusionDuring flexion–extension, the posterior approach is equivalent to the lateral approach, while producing superior stabilization during lateral bend and axial rotation.

Analysis of Mechanical Properties of External Unilateral Fixation Device in the Case of Torque Load

Analysis of Mechanical Properties of External Unilateral Fixation Device in the Case of Torque Load

Unilateral Pedicle Screw Fixation versus Bilateral Pedicle Screw Fixation for Single-Level Lumbar Degenerative Spine: A Systematic Review of Meta-analyses

AIM: The objectives of this study were to perform a systematic literature review based on studies that compare unilateral and bilateral pedicle screw fixation (PSF) in lumbosacral spine fusion to provide recommendations for the treatment of degenerative diseases of the spine, to identify studies with a more complete evidence base, and to identify possible limitations in available literature sources that require further research. METHODS: A literature search was conducted in PubMed, Embase, and the Cochrane Library to identify studies that compare unilateral versus bilateral PSF versus interbody implant placement used the treatment of degenerative diseases of the lumbosacral spine. The study included meta-analyses that met the inclusion criteria. The quality of meta-analyses was evaluated with a measurement tool to assess systematic reviews (AMSTAR) score and the most relevant meta-analysis was determined by applying the Jadad algorithm. RESULTS: Twelve studies fulfilled the eligibility criteria and were included in the study. The results of AMSTAR score ranged from 6 to 9, based on the results, four meta-analysis can be assigned to “middle” category and remained 8 to “upper” category. According to the results obtained, there was no significant difference between unilateral and bilateral PSF; however, unilateral fixation had advantages in the duration of surgical treatment and intraoperative blood loss. СONCLUSION: According to this systematic review, unilateral PSF is an effective fixation method in the formation of lumbosacral spine fusion and has advantages in reducing the duration of surgical treatment and intraoperative blood loss compared to bilateral PSF.

BIOMECHANICAL STUDY OF LATERAL LUMBAR INTERBODY FUSION VERSUS A POSTERIOR FIXATION WITH PEDICLE SCREWS AND RODS USING A HUMAN CADAVERIC MODEL

Lateral lumbar interbody fusion (LLIF) has biomechanical advantages due to the preservation of ligamentous structures (ALL/PLL), and optimal cage height afforded by the strength of the apophyseal ring. We compare the biomechanical motion stability of multiple levels LLIF (4 segments) utilising PEEK interbody 26mm cages to stand-alone cage placement and with supplemental posterior fixation with pedicle screw and rods.Six lumbar human cadaver specimens were stripped of the paraspinal musculature while preserving the discs, facet joints, and osteoligamentous structures and potted. Specimens were tested under 5 conditions: intact, posterior bilateral fixation (L1-L5) only, LLIF-only, LLIF with unilateral fixation and LLIF with bilateral fixation. Non-destructive testing was performed on a universal testing machine (MTS Systems Corp) to produce flexion-extension, lateral-bending, and axial rotation using customized jigs and a pulley system to define a non-constraining load follower. Three-dimensional spine motion was recorded using a motion device (Optotrak).Results are reported for the L3-L4 motion segment within the construct to allow comparison with previously published works of shorter constructs (1-2 segments). In all conditions, there was an observed decrease in ROM from intact in flexion/extension (31%-89% decrease), lateral bending (19%-78%), and axial rotation (37%-60%). At flexion/extension, the decreases were statistically significant (p&lt;0.007) except for stand-alone LLIF. LLIF+unilateral had similar decreases in all planes as the LLIF+bilateral condition. The observed ROM within the 4-level construct was similar to previously reported results in 1-2 levels for stand-alone LLIF and LLIF+bilateral.Surgeons may be concerned about the biomechanical stability of an approach utilizing stand-alone multilevel LLIF. Our results show that 4-level multilevel LLIF utilizing 26 mm cages demonstrated ROM comparable to short-segment LLIF. Stand-alone LLIF showed a decrease in ROM from the intact condition. The addition of posterior supplemental fixation resulted in an additional decrease in ROM. The results suggest that unilateral posterior fixation may be sufficient.

Biomechanical analysis of Instrumented decompression and Interbody fusion procedures in Lumbar spine: a finite element analysis study.

Interbody fusions have become increasingly popular to achieve good fusion rates. Also, unilateral instrumentation is favored to minimize soft tissue injury with limited hardware. Limited finite element studies are available in the literature to validate these clinical implications. A three-dimensional, non-linear ligamentous attachment finite element model of L3-L4 was created and validated. The intact L3-L4 model was modified to simulate procedures like laminectomy with bilateral pedicle screw Instrumentation, transforaminal, and posterior lumbar interbody fusion (TLIF and PLIF, respectively) with unilateral and bilateral pedicle screw instrumentation. Compared to instrumented laminectomy, interbody procedures showed a considerable reduction in range of motion (RoM) in extension and torsion (6% and 12% difference, respectively). Both TLIF and PLIF showed comparable RoM in all movements with < 5% difference in reduction of RoM between them. Bilateral instrumentation showed a more significant decrease in RoM (> 5% difference) in the entire range of motion except in torsion when compared to unilateral instrumentation. The maximum difference in reduction in RoM was noted in lateral bending (24% and 26% for PLIF and TLIF, respectively), while the least difference in Left torsion (0.6% and 3.6% for PLIF and TLIF, respectively) in comparing bilateral with unilateral instrumentation. Interbody fusion procedures were found to be biomechanically more stable in extension and torsion than the instrumented laminectomy. Single-level TLIF and PLIF achieved a similar reduction in RoM with a < 5% difference. Bilateral screw fixation proved biomechanically superior to unilateral fixation in the entire range of motion except in torsion.

Fixation Pins Increase the Accuracy of Implant Surgery in Free-End Models: An In Vitro Study

Implant surgical guides, in combination with implant planning software, have been designed for accurate surgery, especially in partial edentulism. The purpose of this study was to examine the effect of fixation pins of surgical guides on the accuracy of static computer-assisted implant surgeries in a maxillary free-end situation. This invitro study was conducted to compare surgical guides using various fixation pin protocols in implant surgery. A patient dental model with missing teeth from maxillary right first premolar to third molar was used as the study model… Implant placement was planned at maxillary right first premolar, right first molar, and right second molar; Straumann full guide templates were designed and fabricated using the coDiagnostiX software. The experiment involved surgical guides with no fixation pins (NF), buccal unilateral fixation pin (BF), palatal unilateral fixation pin (PF), and bilateral fixation pins on the buccal and palatal sides (BPF), based on the position and number of fixation pins. The deviation between the actual and planned positions was used to evaluate implant accuracy. The fixation pin protocols were the primary predictive variables. Angular, 3D platform, and 3D apex deviations were the primary outcome variables. Statistical analysis was performed using the one-way analysis of variance and Tukey's test (α=0.05). NF generated the maximum angular deviation (3.65±1.39°), 3D platform deviation (1.58±0.55mm), and 3D apex deviation (2.18±0.79mm), whereas BPF produced the minimum angular deviation (1.88±0.86°), 3D platform deviation (1.09±0.51mm), and 3D apex deviation (1.53±0.45mm). A statistically significant difference between NF and BPF in the angular deviation, 3D platform, and apex deviation (P<.0001, P=.009, and P=.002, respectively) was identified. The unilateral fixation pin exerted a significant effect only on the angular accuracy (BF, P=.0018; PF, P=.0001). In a maxillary free-end situation, templates with a fixation pin generate better implant accuracy than those without it. A bilateral fixation pin protocol may produce less deviation than those without fixation pins. The implant accuracy does not appear to be affected by the position of the unilateral fixation pin.

A biomechanical comparison of posterior fixation approaches in lumbar fusion using computed tomography based lumbosacral spine modelling

Extreme lateral interbody fusion (XLIF) may be performed with a standalone interbody cage, or with the addition of unilateral or bilateral pedicle screws; however, decisions regarding supplemental fixation are predominantly based on clinical indicators. This study examines the impact of posterior supplemental fixation on facet micromotions, cage loads and load-patterns at adjacent levels in a L4-L5 XLIF at early and late fusion stages. CT data from an asymptomatic subject were segmented into anatomical regions and digitally stitched into a surface mesh of the lumbosacral spine (L1-S1). The interbody cage and posterior instrumentation (unilateral and bilateral) were inserted at L4-L5. The volumetric mesh was imported into finite element software for pre-processing, running nonlinear static solves and post-processing. Loads and micromotions at the index-level facets reduced commensurately with the extent of posterior fixation accompanying the XLIF, while load-pattern changes observed at adjacent facets may be anatomically dependent. In flexion at partial fusion, compressive stress on the cage reduced by 54% and 72% in unilateral and bilateral models respectively; in extension the reductions were 58% and 75% compared to standalone XLIF. A similar pattern was observed at full fusion. Unilateral fixation provided similar stability compared to bilateral, however there was a reduction in cage stress-risers with the bilateral instrumentation. No changes were found at adjacent discs. Posterior supplemental fixation alters biomechanics at the index and adjacent levels in a manner that warrants consideration alongside clinical information. Unilateral instrumentation is a more efficient option where the stability requirements and subsidence risk are not excessive.

Short-segment fixation and transpedicular bone grafting for the treatment of thoracolumbar spine fracture.

Thoracolumbar fracture is one of the most common fractures of spine. And short-segment posterior fixation including the fractured vertebra (SSPFI) is usually used for the surgical treatment of it. However, the outcomes of SSPFI for different types of thoracolumbar fractures are not clear, and whether it is necessary to perform transpedicular bone grafting is still controversial. This study was conducted to determine the clinical efficacy of SSPFI for the treatment of different types of single-level thoracolumbar fracture, and make clear what kind of fractures need transpedicular bone grafting during the surgery. Patients with single-level thoracolumbar fracture undergoing SSPFI surgery between January 2013 and June 2020 were included in this study. The operative duration, intraoperative blood loss, anterior vertebral height ratio (AVHR) and anterior vertebral height compressive ratio (AVHC) of the fractured vertebra, local kyphotic Cobb angle (LKA), vertebral wedge angle (VWA) and correction loss during follow up period were recorded. Outcomes between unilateral and bilateral pedicle screw fixation for fractured vertebra, between SSPFI with and without transpedicular bone grafting (TBG), and among different compressive degrees of fractured vertebrae were compared, respectively. A total of 161 patients were included in this study. All the patients were followed up, and the mean follow-upped duration was 25.2 ± 3.1 months (6-52 months). At the final follow-up, the AVHR was greater, and the LKA and VWA were smaller in patients with bilateral fixation (6-screw fixation) than those with unilateral fixation (5-screw fixation) of AO type A3/A4 fractures (P < 0.001). The correction loss of AVHR, LKA and VWA in fractured vertebra were significantly great when preoperative AVHC was >50% (P < 0.05). For patients with AVHC >50%, the correction loss in patients with TBG were less than those without TBG at the final follow-up (P < 0.05). SSPFI using bilateral fixation was more effective than unilateral fixation in maintaining the fractured vertebral height for AO type A3/A4 fractures. For patients with AVHC >50%, the loss of correction was more obvious and it can be decreased by transpedicular bone grafting.

Osteoid Osteomas of Spine: From Open to Minimally Invasive Excision of the Nidus – A Case series

Osteoid osteomas of spine are not uncommon and majority of which occurs in posterior elements of lumbar spine. Management of such lesions in spine ranges from open en bloc excision to percutaneous radiofrequency ablation. In this series, we have managed three cases of osteoid osteomas of spine, each managed differently from conventional open technique to minimally invasive method. All three cases underwent appropriate radiological investigations and followed by surgical excision of the lesion and histopathological analysis post-operatively. First case was managed with open excision of the lesion with conventional unilateral pedicle screw stabilisation. Second case, who underwent open excision of the lesion developed recurrence which was managed by re-excision without any further complications. Last case underwent microendoscopic quadrant tubular excision of the tumour with unilateral MISS with pedicle screws. The technique of Microendoscopic quadrant tubular excision of posterior element benign tumour had advantages of small skin incision, less bleeding, clear macroscopic visualisation of the small tumour (enables complete excision of the nidus thus decreasing the recurrence), early mobilisation and shorter hospitalization with effective and complete excision of the tumour better than open method. Further, histological evidence of tumour will be available. The complete excision of nidus using microendoscopic tubular retractors with unilateral fixation in young age gives encouraging results. This case series is followed by review of literature highlighting the role of COX-2 inhibitors in osteoid osteoma, cause for scoliosis and neurological deficit in osteoid osteoma and management of osteoid osteomas of spine. Keywords: Tumor, Osteoid osteoma, Minimally invasive, Dorsolumbar spine, Excision biopsy

Successful outcomes of unilateral vs bilateral pedicle screw fixation for lumbar interbody fusion: A meta-analysis with evidence grading.

Whether it's better to adopt unilateral pedicle screw (UPS) fixation or to use bilateral pedicle screw (BPS) one for lumbar degenerative diseases is still controversially undetermined. To make a comparison between UPS and BPS fixation as to how they work efficaciously and safely in patients suffering from lumbar degenerative diseases. We have searched a lot in the databases through 2020 with index terms such as "unilateral pedicle screw fixation" and "bilateral pedicle screw fixation." Only randomized controlled trials and some prospective cohort studies could be found, yielding 15 studies. The intervention was unilateral pedicle screw fixation; Primarily We've got outcomes of complications and fusion rates. Secondarily, we've achieved outcomes regarding total blood loss, operative time, as well as length of stay. Softwares were installed and utilized for subgroup analysis, analyzing forest plots, sensitivity, heterogeneity, forest plots, publication bias, and risk of bias. Fifteen previous cases of study including 992 participants have been involved in our meta-analysis. UPS had slightly lower effects on fusion rate [relative risk (RR) = 0.949, 95%CI: 0.910 to 0.990, P = 0.015], which contributed mostly to this meta-analysis, and similar complication rates (RR = 1.140, 95%CI: 0.792 to 1.640, P = 0.481), Δ visual analog scale [standard mean difference (SMD) = 0.178, 95%CI: -0.021 to 0.378, P = 0.080], and Δ Oswestry disability index (SMD = -0.254, 95%CI: -0.820 to 0.329, P = 0.402). In contrast, an obvious difference has been observed in Δ Japanese Orthopedic Association (JOA) score (SMD = 0.305, 95%CI: 0.046 to 0.563, P = 0.021), total blood loss (SMD = -1.586, 95%CI: -2.182 to -0.990, P = 0.000), operation time (SMD = -2.831, 95%CI: -3.753 to -1.909, P = 0.000), and length of hospital stay (SMD = -0.614, 95%CI: -1.050 to -0.179, P = 0.006). Bilateral fixation is more effective than unilateral fixation regarding fusion rate after lumbar interbody fusion. However, JOA, operation time, total blood loss, as well as length of stay were improved for unilateral fixation.