Direct Anterior Screw Fixation Research Articles

Anterior odontoid lag screw fixation in type II odontoid fractures

Abstract Background Odontoid fractures are common cervical spine fractures, lead to atlantoaxial instability, and constitute 10–20% of all cervical fractures. Almost two-thirds of all dens fractures are classified as type II according to the Anderson and D’ Alonzo classification system. An increased rate of nonunion of type II odontoid fractures with conservative measures has been reported. The technique of direct anterior screw fixation of the odontoid fracture has become increasingly popular since Bohler reported its use in 1982, and it is now widely used to treat type II. Purpose To evaluate the safety and efficacy of the anterior transodontoid screw fixation in odontoid fractures. Patients and methods Ten patients underwent anterior transodontoid single screw fixation for type II odontoid fractures according to the Anderson and D’ Alonzo classification system. All patients were operated on less than 3 months following trauma. All patients were males apart from one female with their ages ranging from 20 to 59 years with a mean age of 33.9 years. Patients were evaluated clinically and neurologically according to the American Spinal Injury Association scale, and radiologically using plain radiograph, computed tomography scan, and MRI. Results Good clinical and radiological (bony or fibrous) outcomes were achieved in all patients with no screw loosening, backing out, or proximal migration. There were no complications related to surgical procedure or neurological deterioration. Conclusion Direct single anterior screw fixation has proved to be a very successful treatment method for type II odontoid fractures.

Direct Anterior Screw Fixation in a Type II Odontoid Fracture with a Fused C2–C3: A Technical Report

Journal of Minimally Invasive Spine Surgery & Technique (JMISST) is the official journal of the Korean Minimally Invasive Spine Surgery Society (KOMISS) for the publication of research results about minimally invasive spinal surgery (MISS), including studies in spinal endoscopic surgery, minimally invasive procedure for degenerative spine disease, pain intervention, and minimally invasive surgery for spinal fusion or spine trauma, neuroscience, neurology, molecular biology and biomechanics etc. Articles with helpful information for MISS such as reports of rare cases or technical review of special devices or equipment are also available

Direct Anterior Screw Fixation for a Pediatric Odontoid Fracture with Associated Skull Fracture: A Case Report

The upper cervical spine remains the most susceptible region for spinal trauma in children, with odontoid fractures being the most common ones in this age group. Concomitant traumatic brain injuries or skull fractures can pose therapeutic challenges in such cases. We report a case of an 11-year-old boy who presented in the semiconscious state with a deep scalp laceration in the left frontoparietal region. A computed tomography (CT) scan revealed a depressed skull fracture requiring an emergency left frontoparietal decompressive craniectomy and an associated fracture of the odontoid process at the base with anterior displacement. Odontoid fractures usually heal well after immobilization, and the use of instrumented fusion is still debated in view of skeletal immaturity. The usual management of Halo vest could not be instituted in his case owing to the skull fracture, and a single cannulated screw fixation was done under fluoroscopic guidance. Direct operative fusion of the odontoid process has been described in younger children with apophyseal fractures, but the evidence of such procedures is rare in elder children with a fused odontoid process. This case report, thus, confirms the anterior odontoid screw fixation as an effective mode of treatment in children of the 7- to 12-year age group.

Anterior Transcervical Lag Screw Fixation of Type II Odontoid Fracture

Odontoid fracture comprises approximately 20% of all cervical spine fractures. Among them type II fracture accounts for about 65-74%. Presently, direct anterior screw fixation is considered to provide successful outcome with fracture healing of 80% and also preserve C1/C2 rotation movement with benefit of early mobilization and rapid return to normal life style. Recent fracture(<6months) have high fusion rate of 90% with this approach and for remote fracture(≥18months) it reduces to 25%. Here we present a case report of 18 years old female with type II odontoid fracture and underwent anterior transcervical lag screw fixation under C-arm guidance.

Treatment of Dens Fractures with Anterior Screw Fixation.

Direct anterior screw fixation of the dens preserves C1-C2 rotation, and the reported fusion rates range from 88% to 100%. Exact positioning of the patient and use of image intensifiers are mandatory to obtain perfect anteroposterior and lateral views of the axis. The surgical approach is standardized, and the pretracheal layer can be exposed without violating any essential anatomic structures. The perfect entry point is directly anterior-inferior at the base of C2; therefore, the anterior rim of the C2-C3 intervertebral disc must be penetrated. We use a single cannulated screw in most cases: insert the screw in the center of the dens with its tip perforating the cranial, cortical bone of the dens just posterior to the apex. Precise and anatomic closure of the platysma determines the quality of the scar that will be visible after the operation. The patient wears a rigid collar for six weeks, removing it for body care; radiographic evaluations should be performed regularly. In a study of sixty-nine patients with a fracture of the dens, three of the thirteen patients who underwent direct anterior screw fixation had persistent instability and nonunion of the dens four months after surgery. Indications Contraindications Pitfalls & Challenges.

Anterior screw fixation for an odontoid fracture using an Acutrak 4/5 screw: a case report

The direct anterior screw fixation of odontoid fractures by a single cancellous screw, especially for osteoporotic vertebrae, has a potential risk of leading to insufficient stability and implant failures. We experienced good results following surgery using a single Acutrak 4/5 screw to obtain sufficient stability for an odontoid fracture in a patient with osteopenia. The screw is a cannulated self-tapping headless screw and has a tapered profile and full threads with variable pitches, and it can yield sufficient compression force as the screw is inserted. The preoperative severe neck pain of the patient was diminished immediately after the surgery. The patient achieved bone union in a short time and had a good clinical result for at least 3 years. Some biomechanical studies showed that the compression force of Acutrak standard screws was stronger than that of both 4.0-mm cancellous screws inserted with the lag screw technique and Herbert screws, and other studies showed that the compression force of Acutrak 4/5 screws was equivalent to that of 4.5-mm cortical screws. However, there has been no clinical report of surgery using an Acutrak 4/5 screw for odontoid fractures. This is the first clinical report of fixation by an Acutrak 4/5 screw.

Treatment Algorithm for Dens Fractures: Non-Halo Immobilization, Anterior Screw Fixation, or Posterior Transarticular C1-C2 Fixation

The appropriate treatment of dens fractures is unclear. We established a staged treatment protocol for dens fractures and conducted a prospective study to evaluate the outcome of treatment based on this protocol. We prospectively evaluated sixty-nine consecutive patients who presented to our institution with a dens fracture. The mean duration of follow-up was 9.7 months (range, six to fifty-eight months). Fractures were categorized as stable or unstable. Stable fractures were treated by immobilization in a rigid collar. Patients seventy-five years or older with unstable fractures, patients with a neurological deficit, and patients with Anderson and D'Alonzo type-III fractures underwent posterior transarticular C1-C2 stabilization. Unstable fractures in patients younger than seventy-five years were stabilized with direct anterior screw fixation. Thirty-one patients were treated with a Philadelphia collar, twenty-five with posterior transarticular fixation, and thirteen with direct anterior screw fixation. Fracture-healing or solid fusion of C1-C2 was documented in sixty-eight of sixty-nine treated patients at final follow-up. The remaining patient had a stable nonunion of the dens. Secondary procedures were performed in five patients. Our treatment algorithm based on dens fracture type, fracture stability, and patient age was associated with a high success rate. Evaluating fracture stability is crucial when considering nonoperative treatment. External stabilization with a rigid cervical collar was adequate for stable fractures of the dens and was associated with a high healing rate. Posterior transarticular screw fixation of C1-C2 was associated with a high success rate, including in elderly patients. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Anterior single lag screw fixation in type II Dens fracture — indian experience

Increased rate of non-union of Type II Odontoid fractures with rigid external orthosis have been reported. Recently technique of direct anterior screw fixation of the odontoid fracture is being advocated. Here we report the results of 13 cases of Type II dens fracture treated by the above method with an age group ranging from 17 to 73 years. An approach identical to the anterior cervical discectomy was used. Guide tube system devised by Synthes®, single image intensifier and Langenberg retractors was used to place a single cannulated screw through the fracture from C2 body into the dens. Among the 13 cases operated, in 11 cases we were successful. In one case while dissecting the fracture site CSF leak occurred and in another case the guide wire broke leading to abandoning to screw placement. There was no other complication due to the surgical procedure. The follow up period ranged between 2 months to 3 1/2 years. There were no neurological complications or screw fracture. In 9 of the 11 cases (82%) either bony union or fibrous unions have occurred. These results indicate that direct anterior single screw fixation has proved to be a very successful treatment.

Anterior Screw Fixation for a Pediatric Odontoid Nonunion

A case of an odontoid nonunion in a child treated with anterior screw fixation. To demonstrate that an anterior screw procedure can be performed with an odontoid nonunion with resultant fusion to maintain range of motion. A 15-year-old boy presented with pain in his neck following a rugby football injury. Admission plain radiographs and computed tomography scan demonstrated an odontoid nonunion. Radiographs of a previous cervical spine injury 2 years before demonstrated a missed odontoid fracture. The child was initially treated conservatively with halo vest immobilization, which did not result in healing. Direct anterior screw fixation was performed and the fracture united 5 months following surgery. The nonunion was asymptomatic for 2 years until the second injury when it became clinically symptomatic. It did not respond to conservative treatment and was unstable on screening requiring operative intervention. Very few cases have been reported of pediatric odontoid nonunions. If the fracture pattern allows, then direct anterior screw fixation should be considered in order to maintain range of motion at the atlantoaxial articulation.

Odontoid screw fixation for fresh and remote fractures

Fractures of the odontoid process are common, accounting for 10% to 20% of all cervical spine fractures. Odontoid process fractures are classified into three types depending on the location of the fracture line. Various treatment options are available for each of these fracture types and include application of a cervical orthosis, direct anterior screw fixation, and posterior cervical fusion. If a patient requires surgical treatment of an odontoid process fracture, the timing of treatment may affect fusion rates, particularly if direct anterior odontoid screw fixation is selected as the treatment method. For example, type II odontoid fractures treated within the first 6 months of injury with direct anterior odontoid screw fixation have an 88% fusion rate, whereas fractures treated after 18 months have only a 25% fusion rate. In this review, we discuss the etiology, biomechanics, diagnosis, and treatment (including factors affecting fusion such as timing and fracture orientation) options available for odontoid process fractures.

Direct anterior screw fixation for recent and remote odontoid fractures

The management of odontoid fractures remains controversial. Only direct anterior screw fixation provides immediate stabilization of the spine and may preserve normal C1-2 motion. To determine the indications, optimum timing, and results for direct anterior screw fixation of odontoid fractures, the authors reviewed the surgery-related outcome of patients who underwent this procedure at two institutions. One hundred forty-seven consecutive patients (98 males and 49 females) who underwent direct anterior screw fixation for recent (< or = 6 months postinjury [129 patients]) or remote (> or = 18 months postinjury [18 patients]) Type II (138 cases) or III (nine cases) odontoid fractures at the University of Utah (94 patients) and National Institute of Traumatology in Budapest, Hungary (53 patients) between 1986 and 1998 are included in this study (mean follow up 18.2 months). Data obtained from clinical examination, review of hospital charts, operative findings, and imaging studies were used to analyze the surgery-related results in these patients. In patients with recent fractures there was an overall bone fusion rate of 88%. The rate of anatomical bone fusion of recent fractures was significantly (p < or = 0.05) higher in fractures oriented in the horizontal and posterior oblique direction (compared with anterior oblique), but this finding was independent (p > or = 0.05) of age, sex, number of screws placed (one or two), and the degree or the direction of odontoid displacement. In patients with remote fractures there was a significantly lower rate of bone fusion (25%). Overall, complications related to hardware failure occurred in 14 patients (10%) and those unrelated to hardware in three patients (2%). There was one death (1%) related to surgery. Direct anterior screw fixation is an effective and safe method for treating recent odontoid fractures (<6 months postinjury). It confers immediate stability, preserves C1-2 rotatory motion, and achieves a fusion rate that compares favorably with alternative treatment methods. In contradistinction, in patients with remote fractures (> or = 18 months postinjury) a significantly lower rate of fusion is found when using this technique, and these patients are believed to be poor candidates for this procedure.

Direct anterior screw fixation for recent and remote odontoid fractures

Object The management of odontoid fractures remains controversial. Only direct anterior screw fixation provides immediate stabilization of the spine and may preserve normal C1–2 motion. To determine the indications, optimum timing, and results for direct anterior screw fixation of odontoid fractures, the authors reviewed the surgery-related outcome of patients who underwent this procedure at two institutions. Methods One hundred forty-seven consecutive patients (98 males and 49 females) who underwent direct anterior screw fixation for a recent fracture (&lt; 6 months postinjury [129 patients]) or remote (≥ 18 months postinjury [18 patients]) Type II (138 cases) or III (nine cases) odontoid fractures at the University of Utah (94 patients) and National Institute of Traumatology in Budapest, Hungary (53 patients) between 1986 and 1998 are included in this study (mean follow-up period 18.2 months). Data obtained from clinical examination, review of hospital charts, operative findings, and imaging studies were used to analyze the surgery-related results in these patients. In patients with recent fractures there was an overall bone fusion rate of 88%. The rate of anatomical bone fusion of recent fractures was significantly (p ≤ 0.05) higher in fractures oriented in the horizontal and posterior oblique direction (as compared with anterior oblique), but this finding was independent (p ≥ 0.05) of age, sex, number of screws placed (one or two), and the degree or the direction of odontoid displacement. In patients with remote fractures there was a significantly lower rate of bone fusion (25%). Overall, complications related to hardware failure occurred in 14 patients (10%) and unrelated to hardware in three patients (2%). There was one death (1%) related to surgery. Conclusions Direct anterior screw fixation is an effective and safe method for treating recent odontoid fractures (&lt; 6 months postinjury). It confers immediate stability, preserves C1–2 rotatory motion, and achieves a fusion rate that compares favorably with alternative treatment methods. In contradistinction, in patients with remote fractures (≥ 18 months postinjury) a significantly lower rate of fusion is found when using this technique, and these patients are believed to be poor candidates for this procedure.

Dens fractures in the elderly. Results of anterior screw fixation in 19 elderly patients.

Type 2 dens fractures in the elderly may be regarded as fragility fractures due to osteoporosis and are prone to nonunion with closed treatment. We investigated the outcome of direct anterior screw fixation of these fractures in 19 patients over 65 years of age. The type of injury, radiological appearance over time and the clinical outcome were analyzed, with an average follow-up of 4.5 years. Surgery and postoperative treatment were tolerated well in all patients. In 16 cases, bony union was achieved after 3-6 months. 2 pseudarthroses, which required no treatment, occurred. At follow-up, 15 patients had no symptoms. 10 of the patients had diminished rotation. We conclude that anterior screw fixation is a successful therapy in most cases of type 2 dens fractures in the elderly.

In vitro investigations of internal fixation systems of the upper cervical spine

Fresh odontoid fractures of types II and III and in some cases nonunions of the odontoid can be repaired by direct anterior screw fixation preserving C1-C2 motion. The goal of this experimental study was to investigate the biomechanical stability of the fragment achieved by this direct odontoid osteosynthesis according to Böhler. Sixteen human C1-C2 segments with fractures of type II or type III were biomechanically tested in vitro under standardized conditions. Flexion and extension moments, anterior and posterior shear forces were applied, and the motion of the refixed odontoid fragment relative to C2 was determined. The results show that direct screw fixation of the odontoid under the experimental conditions provides sufficient stability for the dens fragment.