Transarticular Screw Research Articles

Biomechanical evaluation of four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs.

This study compared, through biomechanical evaluation under ventral flexion load, four surgical techniques for ventral stabilization of the atlantoaxial joint in dogs. In total, 28 identical atlantoaxial joint models were created by digital printing from computed tomography images of a dog, and the specimens were divided into four groups of seven. In each group, a different technique for ventral stabilization of the atlantoaxial joint was performed: transarticular lag screws, polyaxial screws, multiple screws and bone cement (polymethylmethacrylate-PMMA), and atlantoaxial plate. After the stabilization technique, biomechanical evaluation was performed under ventral flexion load, both with a predefined constant load and with a gradually increasing load until stabilization failure. All specimens, regardless of stabilization technique, were able to support the predefined load without failing. However, the PMMA method provided significant more rigidity (p ≤ 0.05) and also best resisted the gradual increase in load, supporting a significantly higher maximum force (p ≤ 0.05). There was no statistical difference in flexural strength between the transarticular lag screws and plate groups. The polyaxial screws method was significantly less resistant to loading (p ≤ 0.05) than the other groups. The PMMA technique had biomechanical advantages in ventral atlantoaxial stabilization over the other evaluated methods.

Comparison of Surgical Outcomes for Lisfranc Joint Injuries: Dorsal Bridge Plating versus Transarticular Screw versus Combination

Comparison of Surgical Outcomes for Lisfranc Joint Injuries: Dorsal Bridge Plating versus Transarticular Screw versus Combination

Atlantoaxial Anterior Transarticular Screw Fixation: Indications and Surgical Technique.

Posterior atlantoaxial screw fixation is a widely adopted therapeutic option for C1-C2 instability secondary to fractures or dislocation, degenerative diseases, or tumors at this level. Anterior transarticular screw fixation (ATSF) is an effective alternative to the posterior approaches, presenting several advantages despite being scarcely known and rarely chosen.In this chapter, we describe the ATSF step by step, illustrating its variations reported in literature, and we critically analyze the several advantages and contraindications of this technique. Moreover, we provide a list of tips and tricks on the surgical procedure, including critical operating room settings-the result of more than 10years of experience in the field by a senior author.ATSF is a valid strategy for the treatment of different diseases occurring at the level of the atlantoaxial complex that needs consideration. Given the significant learning curve of this strategy, some hints may be essential to begin introducing this technique in the personal armamentarium of a spine surgeon so that they can perform ATSF safely and effectively.

Improving stability of atlantoaxial fusion: a biomechanical study

PurposeThe incidence of atlanto-axial injuries is continuously increasing and often requires surgical treatment. Recently, Harati developed a new procedure combining polyaxial transarticular screws with polyaxial atlas massae lateralis screws via a rod system with promising clinical results, yet biomechanical data is lacking. This biomechanical study consequently aims to evaluate the properties of the Harati technique.MethodsTwo groups, each consisting of 7 cervical vertebral segments (C1/2), were formed and provided with a dens axis type 2 fracture according to Alonzo. One group was treated with the Harms and the other with the Harati technique. The specimen was loaded via a lever arm to simulate extension, flexion, lateral flexion and rotation. For statistical analysis, dislocation (°) was measured and compared.ResultsFor extension and flexion, the Harati technique displayed a mean dislocation of 4.12° ± 2.36° and the Harms technique of 8.48° ± 1.49° (p < 0.01). For lateral flexion, the dislocation was 0.57° ± 0.30° for the Harati and 1.19° ± 0.25° for the Harms group (p < 0.01). The mean dislocation for rotation was 1.09° ± 0.48° for the Harati and 2.10° ± 0.31° for the Harms group (p < 0.01). No implant failure occurred.ConclusionThis study found a significant increase in biomechanical stability of the Harati technique when compared to the technique by Harms et al. Consequently, this novel technique can be regarded as a promising alternative for the treatment of atlanto-axial instabilities.

Functional Outcome of Lisfranc Injury after Open Reduction and Internal Fixation with Transarticular Screws: A Prospective Observational Study

Functional Outcome of Lisfranc Injury after Open Reduction and Internal Fixation with Transarticular Screws: A Prospective Observational Study

Spinal navigation with preoperative computed tomography

Safe placement of posterior cervical-sacral pedicle screws, S2-Ala-iliac screws, iliac screws, transarticular screws C1/2, translaminar screws C2 or cervical lateral mass screws under the guidance of spinal navigation. All posterior spinal instrumentations with screws: instabilities and deformities of rheumatic, traumatic, neoplastic, infectious, iatrogenic or congenital origin; multilevel cervical spinal stenosis with degenerative instability or kyphosis of the affected spinal segment. There are no absolute contraindications for spinal navigation. Cervical spine: Prone position on agel mattress, rigid head fixation, e.g., with Mayfield tongs; if appropriate, closed reduction under lateral image intensification; thoracic + lumbar spine: prone position on acushioned frame; midline posterior surgical approach at the level of the segments to be instrumented; if necessary, open reduction; insertion of the cervical/upper thoracic screws under the guidance of spinal navigation; if necessary, posterior decompression; instrumentation longitudinal rods; if fusion is to be obtained, decortication of the posterior bone elements with ahigh-speed burr and onlay of cancellous bone or bone substitutes. In stable instrumentations, no postoperative immobilization with orthosis is necessary, removal of drains (if used) 2-3days postoperatively (postop), removal of the sutures 14days postop, clinical and x‑ray controls 3and 12months postop or in case of clinical or neurological deterioration. Numerous studies showed that the use of spinal navigation significantly reduces implant malplacement rates, complications, and revision surgery. Furthermore, intraoperative radiation exposure to the operation team can be reduced by up to 90%.

Postoperative outcomes of combined surgery comprising dorsal laminectomy, transarticular screws, pedicle screws and polymethylmethacrylate for dorsal fixation in 21 dogs with degenerative lumbosacral stenosis.

To retrospectively review the efficacy of combined surgery comprising dorsal laminectomy and dorsal fixation using screws and polymethylmethacrylate as treatment for dogs with degenerative lumbosacral stenosis (DLSS). 21 client owned dogs diagnosed with DLSS and treated surgically. Based on clinical records, signalments, clinical signs, findings from orthopedic and neurological examinations, imaging findings, and postoperative complications were evaluated at the following time points: preoperatively, postoperatively, and 3, 6, 12, 24, and 36 months after surgery. In all 21 cases, clinical signs were alleviated, proprioceptive deficits were improved from 3 months after surgery, and no recurrence of clinical signs was observed during the observation period. Minor complications were observed in 6 cases (28.6%), including implant failure in 2 (9.5%), delayed healing of surgical wounds in 2 (9.5%), seroma in 1 (4.8%), and swelling of the affected area in 1 (4.8%). There was no case with major complications. Combined surgery comprising dorsal laminectomy and dorsal fixation using screws and polymethylmethacrylate is a useful treatment that can improve long-term clinical signs in dogs with DLSS.

Risk factors for atlantoaxial dislocation in rheumatoid arthritis: A comparative study.

The objective of the study was to assess clinical and imaging features of rheumatoid arthritis associated with atlantoaxial dislocation (RA-AAD) in comparison to RA without AAD (RA-C) and to identify the associated factors to AAD. This was a retrospective comparative study including RA patients over 18years old. The control group of RA-C was matched according to age (±2years), gender, and RA duration (±2years). General data, RA characteristics, AAD features, and treatment modalities were recorded. Statistical analysis was performed to determine the predictive factors of AAD. A total of 120 patients were included (78 RA-AAD and 42 RA-C); sex-ratio was 0.15. Mean age was 58.55±9.14years (RA-AAD) versus 60.43±10.78years (RA-C), (p=0.31). Regarding RA features, RA-AAD patients have significantly a higher rheumatoid factor (RF) rate (p=0.002), extra-articular manifestations (p=0.009) especially osteoporosis (p<10-3 ), eye involvement (p=0.02), coxitis (p<0.0001), Disease Activity Score (DAS28) (p<10-3 ), and global health status scale (HAQ) (p=0.003). X-ray analysis showed pathologic PADI (<14mm) in 51.6% of cases. The AADI was pathological (>3mm) in 100% of patients with the following distribution: 67.9% between (3-6mm) and 23.3% between (6-9mm). Atlantoaxial dislocation (AAD) was presumed anterior (85.4%), lateral (7.3%) and rotatory (7.3%). The abnormalities observed on magnetic resonance imaging (MRI) were: C1-C2 synovitis (61%), confirmed AAD (34.1%) and basilar impression (4.9%). AAD diagnosed by cervical MRI was anterior in 89.8% of cases, lateral (5.3%) and with a double ascending and anterior component in 4.9% of cases. An immobilisation with a type C4 cervical collar was indicated for all the patients and five of them had boluses of corticosteroid (methylprednisolone 1g/day) for three consecutive days. C1-C2 arthrodesis by trans-articular screwing was performed in four patients with neurological signs or pathological measurements on cervical MRI. The outcome was favourable in 100% of cases after surgical treatment with improvement in neck pain and neurological condition within a mean decline of 4±3years [1-7]. Multivariate analysis identified coxitis, osteoporosis, high baseline DAS28, and a high rate of RF positivity as predictive factors of AAD. Our results confirmed that predictive factors of AAD were related to higher disease activity and structural damage. These modifiable factors may be prevented by tight control, early treatment, and educating RA patients to improve treatment adherence.

Comparison of flexible fixation and screw fixation for isolated Lisfranc ligament injuries: A protocol for a meta-analysis of comparative studies.

Background:The frequency of isolated Lisfranc ligament (ILL) injuries has been increasing recently with the increase in low-energy trauma resulting from sports injuries. For ILL injuries, the optimal method of fixation still remains controversial. The traditional fixation method is achieved by trans-articular screws, but recently, dorsal bridge plates and suture button (SB) fixation have become alternatives. Some biomechanical studies have showed that SB fixation can provide adequate strength compared to trans-articular screws. Therefore, a meta-analysis is imperative to provide evidence on whether flexible fixation is comparable to screw fixation for treatment of ILL injuries.Methods:We will conduct a comprehensive literature search in PubMed, Cochrane Library, EMBASE and Web of Science databases and for comparative studies. We will apply the risk-of-bias tool of the Cochrane Collaboration for Randomized Controlled Trials to assess the methodological quality. Risk-of-Bias Assessment Tool for Non-randomized Studies was used to evaluate the quality of comparative studies. Statistical analysis will be conducted using RevMan 5.4 software (Cochrane Collaboration, London, England).Results:This systematic review will evaluate the functional outcomes and radiographic results of flexible fixation for treatment of ILL injuries.Conclusion:The conclusion of this study will provide evidence for judging whether flexible fixation is superior to screw fixation for treatment of ILL injuries.

Nitinol Shape Memory Staple Fixation of Lisfranc Fractures is Safe and Efficacious

Category: Trauma; Midfoot/Forefoot; Sports Introduction/Purpose: Surgical treatment of Lisfranc fractures has evolved from arthrodesis or transarticular screw fixation to joint preserving modalities (suture buttons and/or dorsal spanning plates), the latter commonly requiring removal due to metalwork irritation and to restore motion at the 1st-MTPJ. Shape memory staples formed from Nitinol exploit its biomechanical properties of; low Young's modulus, super elasticity and high ductility. To produce a robust implant that generates greater compressive forces at its distal end compared to traditional 316L stainless steel compression staples. Permitting the construction of a rigid fixation for Lisfranc fractures that is achieved with transarticular screws or plate fixation, but is mobile and elastic as with suture buttons. This study aims to assess the surgical outcomes of staple fixation in acute Lisfranc fractures. Methods: A prospective study to assess for union and necessity for revision surgery was completed for consecutive Lisfranc fractures treated with Nitinol shape memory staple fixation from June 2020 at a single U.K. Level 1 Major-Trauma-Centre. All operations were performed or supervised by a single fellowship trained Major Trauma Foot &amp; Ankle Surgeon through a EHL bed approach to access the base of the 2nd MT and cuneiforms. Relevant joints were debrided and reduced, held with K-wires and reduction clamps to allow for the placement of the staples. A triangular configuration for the placement of three staples (2nd MT to Middle Cuneiform, 2nd MT to Medial Cuneiform, Middle to Medial Cuneiform). Reduction of the Lisfranc complex was confirmed on intra-operative fluoroscopy. Patients were non-weight bearing for 4 weeks with appropriate VTE prophylaxis. Staples were placed so as to not penetrate the plantar cortex and inter-cuneiform instability was assessed and confirmed intra- operatively. Results: Results from 19 consecutive patients were analysed, consisting of 9 men 10 women, with a mean age of 44 years (19-76). Seven patients sustained high energy trauma. Mean time to theatre was 18 days (5-28) from date of injury. Mean total operative time was 70 minutes, (27-154) with an mean tourniquet time of 63 minutes. An mean length of follow-up was 13.5-months (range 6-20 months), with a 100% union rate on weight-bearing radiographs and no incidences of post-operative complications requiring further medical or surgical intervention. No patients reported symptomatic implant irritation which required consideration of metalwork removal. The average FADI score was 73/104 (70%) at longest follow-up. Conclusion: Nitinol shape memory staple fixation of Lisfranc fractures is safe and efficacious, removing the necessity for metalwork removal as is commonly seen with dorsal bridging plates whilst maintaining the structural rigidity of plate/trans-articular screw fixation at the same time as allowing for physiological motion at the 1st-MTPJ. Patient reported outcome measures of this technique demonstrate equitable outcomes to more conventionally used techniques. This is the largest series of shape memory alloy staple fixation of acute Lisfranc injuries the authors are aware of and demonstrates that this technique should be considered a part of a surgeons' armamentarium when treated Lisfranc injuries.

Surgical controversies and current concepts in Lisfranc injuries.

Lisfranc injuries, not as rare as previously reported, range from ligamentous to complex fracture-dislocations. Anatomical studies have identified a complex of discrete structures, and defined the anatomical characteristics of the Lisfranc joint. A narrative evidence-based review encompassed and analyzed published systematic reviews. Outcomes included clinical and surgical decision-making, including clinical-presentation, diagnosis, pathological-assessment, surgical-management techniques and indications, post-surgical care and comparative outcomes. Better understanding of the Lisfranc complex anatomy aids surgical treatment and tactics. Prognosis is related to injury severity, estimated by the number of foot columns affected. Surgical outcome is determined by anatomical reduction for most fixation and fusion techniques. Appropriate treatment allows return to sport, improving outcome scores. Identification of Lisfranc injuries may be improved by imaging modalities such as weight-bearing computer tomography. Recent evidence supports dorsal plate fixation as a result of better quality of reduction. In complex injuries, the use of combined techniques such as trans-articular screw and plate fixation has been associated with poorer outcomes, and fusion may instead offer greater benefits. Open reduction is mandatory if closed reduction fails, highlighting the importance of understanding surgical anatomy. If anatomical reduction is achieved, acute arthrodesis is a safe alternative to open reduction internal fixation in selected patients, as demonstrated by comparable outcomes in subgroup analysis. The current controversies in surgical treatment remain around techniques and outcomes, as randomized controlled trials are infrequent.

Referencing for anterior atlantoaxial trans-articular osteosynthesis: a radiological study and proposal of a decisional algorithm.

Anterior trans-articular C1-C2 screw placement can be considered as a surgical alternative in different conditions affecting the atlantoaxial region. While its rigidity is similar to posterior Magerl and Harms techniques, it also provides some surgical advantages. However, the literature lacks papers exhaustively describing indication criteria, surgical steps, and pitfalls. This is a radiological study on 100 healthy subjects. Thin-layer CT scans of the craniovertebral junction were retrieved from the institutional database. The coronal inclination of the C1-C2 joint rim and the depth of the entry point of the screw with respect to the anterior profile of C2 were measured. The antero-posterior and the medio-lateral surgical corridors for the screw placement, and the wideness of the target area on the upper surface of C1 were also measured. The multivariate analysis showed that the coronal inclination of the C1-C2 articular joint rim strongly influences the surface extension of the C1 target area; the depth of the entry point and the C1-C2 articular rim inclination seem to be independent factors in influencing both the medio-lateral and the antero-posterior surgical corridors wideness. A decisional algorithm on whether to perform an anterior or posterior approach to the atlantoaxial region was also proposed. We can conclude that, as much as the C1-C2 articular rim is tending to the horizontal line, and as deeper is the entry point of the screw on the anterior profile of C2, as easier the anterior C1-C2 trans-articular screw placement will result.

Two Orthogonal Nitinol Staples and Combined Nitinol Staple-Screw Constructs for a First Metatarsophalangeal Joint Arthrodesis: A Biomechanical Cadaver Study.

End-stage hallux metatarsophalangeal (MTP) joint arthritis is commonly treated with arthrodesis using stainless steel or titanium implants. These implants provide static compression that is maximal at the time of implant insertion. Alternatively, nitinol staples are capable of dynamic compression. They have most frequently been used for midfoot arthrodesis procedures. However, their biomechanical performance during hallux MTP arthrodesis has not been described. 8 matched pairs of cadaveric feet (4 female, 4 male) were prepared for hallux MTP arthrodesis using cup and cone reamers. Cadaveric pairs were then instrumented with either (1) a transarticular lag screw and dorsal nitinol staple or (2) orthogonal nitinol staples placed dorsally and medially. Walking in a short leg cast for 6 weeks was simulated by applying 90-N forces at 3 Hz to the plantar proximal phalanx for up to 250 000 cycles. Failure was defined as catastrophic implant failure or plantar gapping beyond 7 mm. 15 of 16 specimens failed cyclic loading. All 8 specimens fixed with orthogonal staples failed at an average of 37 ± 81 cycles. 7 of 8 specimens fixed with a dorsal staple and crossed screw failed at 14 900 ± 39 000 cycles. Collectively, 5 specimens failed because of bone fracture (1 in orthogonal staples, 4 in staple-screw group) and 10 failed because of excessive gap formation (7 in orthogonal staples, 3 in staple-screw group). The number of cycles to failure was significantly lower (P = .0469) in the orthogonal staple constructs compared with the dorsal staple and crossed screw constructs. The tested constructs permit significant motion at the first MTP fusion surface during simulated protected weightbearing. Although multiple in vivo factors should be considered when extrapolating results from this cadaveric study, this motion may result in clinical failure with early postoperative weightbearing protocols. We report the first biomechanical evaluation of hallux MTP arthrodesis using modern nitinol staples in 2 separate constructs.

Biomechanical Comparison of Fiber Tape Device Versus Transarticular Screws for Ligamentous Lisfranc Injury in a Cadaveric Model

Background: The preferred method of fixation and surgical treatment for ligamentous Lisfranc injuries is controversial. Transarticular screws, bridge plating, fusion, and flexible fixation have been described, yet none have demonstrated superiority. Furthermore, screw fixation and plating often require secondary surgery to remove implants, leading surgeons to seek alternative fixation methods. Purpose: To compare transarticular screws and a fiber tape construct under a spectrum of biomechanical loads by evaluating the diastasis at 3 joints in the Lisfranc complex. Study Design: Controlled laboratory study. Methods: Eight matched pairs of fresh, previously frozen lower extremity cadaveric specimens were fixed with either 2 cannulated transarticular crossed screws or a fiber tape construct with a supplemental intercuneiform limb. The diastasis between bones was measured at 3 midfoot joints in the Lisfranc complex: the Lisfranc articulation, the second tarsometatarsal joint, and the intercuneiform joint. Measurements were obtained for the preinjured, injured, and fixation conditions under static loading at 50% donor body weight. Specimens then underwent cyclic loading performed at 1 Hz and 100 cycles, based on 100-N stepwise increases in ground-reaction force from 100 to 2000 N, to simulate postoperative loading from the partial weightbearing stage to high-energy activities. Failure of fixation was defined as diastasis ≥2 mm at the Lisfranc articulation (second metatarsal–medial cuneiform joint). Results: There were no significant differences in diastasis detected at the Lisfranc articulation or the intercuneiform joint throughout all loading cycles between groups. All specimens endured loading up to 50% body weight + 1400 N. Up to and including this stage, there were 2 failures in the cannulated transarticular crossed-screw group and none in the fiber tape group. Conclusion: The fiber tape construct with a supplemental intercuneiform limb, which does not require later removal, may provide comparable biomechanical stability to cannulated transarticular crossed screws, even at higher loads. Clinical Relevance: Ligamentous Lisfranc injuries are common among athletes. Therefore, biomechanical evaluations are necessary to determine stable constructs that can limit the time to return to play. This study compares the biomechanical stability of 2 methods of fixation for ligamentous injury through a wide spectrum of loading, including those experienced by athletes.

Comparing treatment of proximal phalangeal fractures with intramedullary screws versus plating

PurposePhalangeal fractures are the most common injuries in humans and account for approximately 10% of all fractures. With plate fixation, anatomic reduction is achievable in most cases, but extension lag is seen in up to 67%. Intramedullary headless screw offers treatment of unstable proximal phalangeal fractures using a minimally invasive procedure with very few complications. One of the major disadvantages of this technique is the transarticular screw position, damaging the articular surface and thus preventing very proximal fractures from being treated with a distally inserted screw. In this study, we present a modified approach to the fixation of the proximal phalangeal fractures and compare outcomes with plate osteosynthesis.Materials and methodsTwenty-nine patients with 31 comparable fractures of the proximal phalanx were treated either with a plate (14) or with minimal invasive cannulated compression screw (17). Pain, strength, range of motion (ROM), work disability and QuickDASH score were assessed.ResultsTAM was significantly better in the screw group. The extension lag was worse in the plate group. Plate removal had to be performed in 13 of 14 the cases, while the screw had to be removed in only 3 cases. The average duration of work disability was 9.9 weeks in the plate group, compared to 5.6 weeks in the screw group.ConclusionMinimally invasive screw osteosynthesis not only has the advantage of significantly shorter work disabilities, but also shows remarkably improved postoperative range of motion. In contrast to plate osteosynthesis, removal of the screw is only necessary in exceptional cases. With the antegrade screws position, even difficult fractures close to the base can be treated without destroying any articular surface. In proximal phalanx fractures with both options of plate or single-screw osteosynthesis, we recommend minimal invasive cannulated screw osteosynthesis.

Accuracy of a patient-specific 3D-printed drill guide for placement of bicortical screws in atlantoaxial ventral stabilization in dogs.

Atlantoaxial instability (AAI) in dogs refers to abnormal motion at the C1–C2 articulation due to congenital or developmental anomalies. Surgical treatment options for AAI include dorsal and ventral stabilization techniques. Ventral stabilization techniques commonly utilize transarticular and vertebral body screws or pins. However, accurate screw insertion into the vertebrae of C1 and C2 is difficult because of the narrow safety corridors. This study included 10 mixed dogs, 1 Pomeranian, and 1 Shih-Tzu cadaver. All dogs weighed <10 kg. Each specimen was scanned using computed tomography (CT) from the head to the 7th cervical vertebrae. This study used 12 bone models and 6 patient-specific drill guides. Bone models were made using CT images and drill guides were created through a CAD (computer-aided design) program. A total of six cortical screws were used for each specimen. Two screws were placed at each of the C1, C2 cranial, and C2 caudal positions. Postoperative CT images of the cervical region were obtained. The degree of cortex breaching and angle and bicortical status of each screw was evaluated. The number of screws that did not penetrate the vertebral canal was higher in the guided group (33/36, 92%) than in the control group (20/36, 56%) (P = 0.003). The screw angles were more similar to the reference angle compared to the control group. The number of bicortically applied screws in the control group was 28/36 (78%) compared to 34/36 (94%) in the guided group. Differences between the preoperative plan and the length of the applied screw at the C1 and C2 caudal positions were determined by comparing the screw lengths in the guide group. The study results demonstrated that the use of a patient-specific 3D-printed drill guide for AAI ventral stabilization can improve the accuracy of the surgery. The use of rehearsal using bone models and a drilling guide may improve screw insertion accuracy.

CLINICORADIOLOGICAL AND FUNCTIONAL OUTCOMES OF LISFRANC INJURIES MANAGED BY DIFFERENT TREATMENT MODALITIES IN A TERTIARY CARE CENTRE

Background: The lisfranc injuries are and have poor functional outcomes. The aims of this study was to compare the functional and radiological outcomes of lisfranc injuries by different treatment modalities. Methods: A study of 46 patients treated for a Lisfranc injuries, over a period of 6 years at a tertiary care centre was performed. Of these 6 were managed conservatively. 22 by transarticular screws alone , 7 by K wires only and remaining 11 by combination of transarticular screw and K wire The primary outcome measures included the American Orthopaedic Foot and Ankle Society score, and the secondary outcome was the radiological Wilppula classification of anatomical reduction. Results: Road traffic accidents(RTA) was the most common mode of trauma in the study. The average length of followup after surgery was 29 months and mean AOFAS score achieved was 73.12. The analysis of radiological long-term data according to Wilppula showed 32 patients with good results, 9 with fair results and 5 with poor results. Conclusion: We concluded in our study that better functional outcomes were seen with anatomic reduction, independent of the fixation technique.

C1-C2 Transarticular Anterior Fixation for the Treatment of Atlantoaxial Traumatic Dislocation: A Clinical Case.

Fractures of the odontoid apophysis are one of the most frequent lesions in the elderly population, and an increasingly preponderant problem with the progressive aging of the world population. In the present work, we report a clinical case of an 88-year-old male patient who suffered a fall resulting in a type-II fracture of the odontoid apophysis on the Anderson-D'Alonzo classification. Given the age and comorbidities of the patient, we decided to perform osteosynthesis of the fracture through anterior fixation with a transarticular screw in combination with fixation with an odontoid screw. This technique enables the necessary stability for the consolidation of Anderson-D'Alonzo's type II odontoid apophysis fracture, with the advantage of the lower levels of dissection of the cervical extensor musculature and hemorrhage resulting from this aggression when compared with the posterior approach; moreover, it is a readily-available technique that yields clear benefits in the treatment of this pathology in the geriatric population.

Comparison of Two Surgical Techniques for the Treatment of Canine Disc Associated-Cervical Spondylomyelopathy.

ObjectiveTo compare prosthetic disc and vertebral distraction stabilization in dogs with disc-associated cervical spondylomyelopathy (DA-CSM).Study DesignA retrospective clinical study.Animals25 dogs.MethodsDogs presenting with clinical signs and MRI findings compatible with DA-CSM underwent surgery. Implantation of the Adamo's prosthetic disc (PD) or vertebral distraction-stabilization (DS) with intervertebral cage, ventral locking plates, and dorsal transarticular screws was performed. All dogs were followed-up and evaluated clinically for a minimum of 1 year and radiographically for at least 3 months. In particular, we focused on the evaluation of subsidence (the degree of vertebral collapse).ResultsTwenty-five dogs were enrolled: 12 with PD implantation and 13 with DS implantation. Of these, 24 dogs were followed-up at 1 year. Overall, 12 dogs improved (4 PD and 8 DS), eight were stable (4 PD and 4 DS), and four deteriorated (3 PD and 1 DS). Deterioration was more common in PD cases, especially soon after surgery. In a few PD cases, a second surgery was necessary. The most common complication in dogs with DS was discospondylitis. Subsidence was detected in 11 PD and 7 DS dogs. Subsidence was more severe and occurred sooner after surgery in PD cases compared to DS cases. DS cases were more prone to clinical improvement and less prone to subsidence than PD cases in this study. However, the statistical evidence was weak owing to the small sample size.ConclusionThe preliminary results suggest that prosthetic disc implantation is more prone to clinical and radiographic failures than distraction stabilization.Clinical RelevanceThe DS technique is a valuable surgical option for treating dogs with DA-CSM, with favorable short- and long-term clinical and radiographic outcomes.

The Comparison Between Transarticular Screw Fixation and Segmental Screw-Rod Fixation for Posterior Fusion of the C1-2 Segment: A Systematic Review and Meta-Analysis

Both transarticular screw fixation (TAS) and segmental screw-rod fixation (SF) have been widely performed for C1-2 fusion; however, just only small clinical studies and a few meta-analyses comparing the 2 surgical techniques for C1-2 posterior fusion have been reported. We searched the Cochrane, Embase, and Medline databases for articles comparing the intraoperative and postoperative outcomes of TAS and SF for C1-2 posterior fusion with April 14, 2022, as the publication cutoff date. The odds ratio (OR) and standardized mean difference were used to analyze differences in outcomes between the 2 abovementioned surgical techniques. A P value<0.05 was considered statistically significant. A total of 5101 publications were assessed, and 6 studies were finally included in the study. In terms of the fusion rate, SF produced significantly better outcomes than TAS did (OR=2.96, P=0.02). With respect to surgical outcomes, blood loss and operation times were significantly lower in the TAS group than those in the SF group (P=0.008 and P<0.00001, respectively). The rate of vertebral artery injury was significantly lower in the SF group than that in the TAS group (OR=3.95, P=0.04). However, other complications, such as screw malposition, infection, hardware failure, and nonunion, were not significantly different between the 2 groups. SF showed a greater fusion rate and lower risk of vertebral artery injury than TAS did, but TAS showed less blood loss and lower operation times than SF.