C1 Lateral Mass Screw Fixation Research Articles

Perioperative complications associated with fluoroscopy C1 lateral mass screw fixation (Goel technique) versus computed tomography-guided navigation technique: A review of 202 cases from the German Spine Registry (DWG-Register).

Overview of the literature - Fractures of the C1 constitute 3%-13% of all cervical spine injuries in adults. Most isolated C1 fractures are stable and can be treated nonoperatively with external immobilization. Traditional surgical options for C1 fracture treatment are occiput-to-C2 fusion or C1 with lateral mass screws (LMSs). Purpose - The aim is to assess the management and perioperative complications of C1 fractures undergoing LMS fusion between fluoroscopy and computed tomography (CT)-guided navigation. This was a retrospective multicenter study of data from the DWG-Register of patients who underwent operative treatment for C1 traumatic fracture with LMSs from January 2017 to September 2022. Inclusion criteria - traumatic injury and age > 18 years old. In total, 202 patients with traumatic C1 fracture requiring spinal surgery were identified in the registry; n = 175 (Group 1) were treated conventionally without CT-guided navigation and n = 27 were treated with CT-guided navigation (Group 2). C1-LMS was principally performed by spine surgeons n = 90 (53.4%) and n = 72 (18.5%) by neurosurgeons in both the groups. Intraoperative adverse events were as follows: dural tear in group 1 n = 0 and in group 2 n = 1, vascular injury, with one case in group 1 and no cases in group 2. General complications were: cardiovasculars in group 1 n = 6 (3.4%) and Group 2 n = 4 (14.8%) (P = 0.03), pulmonary complications in group1 n = 2 (1.1%) and n = 9 in group 2 (33.3%) (P < 0.001), stroke n = 1 (0.57%) in group1 and n = 4 in group 2 (14.8%) (P < 0.001), gastrointestinal bleeding n = 1 (0.57%) in group1 and no cases in group 2, renal insufficiency n = 2 (1.1%) in group 1 and n = 3 (11.1%) in group 2 (P = 0.01). One death was recorded in group 2 (3.7%). This series of 404 screws placed in 202 patients over 5 years who underwent two types of C1 fracture fixation had a considerably lower incidence of screw malposition and vertebral artery injury than has previously been reported in the literature. C1 screws can be safely placed with a low risk of vertebral artery and neurologic injury with and without CT-guided navigation support.

Evaluation of Craniometric Parameters and Efficacy of Posterior Surgical Intervention Types in Basilar Invagination Patients

OBJECTIVEBasilar invagination is one of the most frequently observed abnormalities at the craniovertebral junction, in which the odontoid process of C2 prolapses into the foramen magnum. METHODSThe current study included 27 patients who underwent surgery for basilar invagination between October 2013 and January 2023. The study group was divided into 2 groups according to basilar invagination types; type I (the presence of type A atlantoaxial instability and instability is the main pathology) and type II (the presence of type B and C atlantoaxial instability and skull base dysgenesis is the main pathology). Craniometric parameters included in the study were; atlantodental interval, posterior atlantodental interval, Chamberlain’s line violation, clivus-canal angle, Welcher’s basal angle, and Boogaard angle. RESULTSThe mean age of the patients was 24.30 ± 14.36 years (5-57 years). Fourteen patients (51.9%) were female, and 13 patients (48.1%) were male. Ten patients (37%) had type I basilar invagination, 17 patients (63%) had type II basilar invagination. Preoperative and postoperative atlantodental interval and Boogaard angle were significantly higher in type I basilar invagination, as preoperative and postoperative posterior atlantodental interval and clivus-canal angle were significantly higher in type II basilar invagination. There was a positive strong correlation between Chamberlain‘s line violation and Boogaard angle. Postoperative Chamberlain‘s line violation was significantly higher in occipitocervical fixation (p=0.035). C1 lateral mass screw fixation was found more successful in Chamberlain‘s line violation correction than occipital plates. Occipitocervical fixation was found to be associated with higher postoperative Nurick scores (p=0.015) and complication rates (p=0.020). Cages applied to the C1-C2 joint space were found to be associated with higher fusion rates (p = 0.023) and lower complication rates (p = 0.024). CONCLUSIONSIn the present study, it was found that C1-C2 fixation was more successful in correcting craniometric parameters and had lower complication rates than occipitocervical fixation. In appropriate patients, it was determined that cage application increased the success rates of the operations.

Surgical management of os odontoideum: An Algerian center experience.

ABSTRACTBackground:Os odontoideum (OO) is a craniovertebral junction malformation of unknown origin. In most times, this lesion is highly unstable demanding surgical management. We present our series of OO surgical management and we discuss clinical, radiological, and management aspects of this pathology via our experience and literature opinions.Methods:This is a retrospective study of patients operated on at our department between May 2014 and May 2021 for OO. All patients were explored with plane X-rays and computed tomography (CT). In some cases, magnetic resonance imaging (MRI) was necessary. Posterior C1–C2 or C1-C3 fixation with polyaxial screws and rod fixation was used. In postoperative, the patient is asked to put Philadelphia collar for 3 months. Hospitalization periods vary between 3 and 7 days. After discharge, all our patients are followed up regularly in consultation. Control radiographs of the occipito cervical region were performed. After 3 months postoperatively, the CT scan is performed on all our patients to assess the quality of fusion. Patient's follow-up ranges from 4 months to 6 years.Results:Fifteen patients were included in this study; nine males (60%) and six females (40%); with mean age of 32.5 years old. Ten patients (67%) presented motor weakness, three patients (20%) with neck pain, one patient (6.5%) with torticollis, and one patient (6.5%) presented vertigo. No notable cervical trauma was present in six patients (40%) and in nine patients (60%), a remote history of traumatism was noted. All cases of our series presented mobile OO. Normal thickness of the C2 pedicle was noted in nine patients (60%). In two patients (13%), there was hypoplasia of one pedicle and in four patients (27%) both pedicles. MRI showed direct signs of spinal cord aggression: simple compression, myelomalacia, strangulation, or hypotrophy. C1 lateral mass screw fixation was performed in all patients; and according to C2 morphology: nine patients underwent C1-C2 pedicular fixation, in one patient, bilateral crossing C2 laminar screws technique, in three patients, we skipped C2 to perform a C1-C3 articular fixation, and in two patients, C1-C2-C3 fixations were performed. All patients improved clinically. In one patient, we noted an infection resulting in bad wound healing this infection was successfully treated with no complications. In the patient with bilateral crossing C2 laminar screws technique, CT control objectified 4 mm exceeding of one screw; the patient was reoperated and the screw was slightly pulled back. No other complications were noted.Conclusion:Congenital origin of OO is always evoked. C1-C2 fixation according to Goel and Harms technique with grafting proved its safety, providing high fixation quality with the acceptable biodynamic outcome. Once treated, the prognostic of OO is in general good, and improvement is observed in most patients with few complications.

Atlantoaxial osteoarthritis: a well-established entity that remains frequently overlooked

Painful atlantoaxial (C1-2) osteoarthritis (AAOA) has been described over 40 years ago. The condition may cause severe pain symptoms and disability related to the unilateral suboccipital pain and, in some cases, occipital neuralgia. One of the greatest challenges with AAOA is making the diagnosis. Diagnosis is commonly missed or delayed when headaches are treated in isolation or when pain is attributed to subaxial spondylosis. Here we present an illustrative case involving a 67-year-old male presenting with classic painful AAOA. After failing conservative treatments, he was evaluated with morphologic, radiological studies and a diagnostic injection. He was successfully treated with bilateral, navigation guided C1 lateral mass and C2 pedicle screw fixation and fusion. To conclude, when there is clinical suspicion for painful AAOA, providers have numerous diagnostic modalities, including newer hybrid techniques, that can be used to solidify the diagnosis. When conservative efforts fail, C1-2 fusion is an effective and enduring treatment for most patients.

Endoscopically-Assisted Percutaneous Unilateral Atlantoaxial Screw-Rod Nonfusion Fixation Treatment for Type II Odontoid Fractures in Geriatric Patients: Case Series and Technical Note

Considerable controversy exists regarding the optimal treatment for type II odontoid fractures in geriatric patients. Surgical intervention can help patients return to their prior level of function as rapidly as possible while avoiding the morbidity and mortality associated with prolonged and bedbound hospitalization. However, the optimal treatment is still a difficult choice for patients with increased risk from anesthesia. The objective of our study was to describe an innovative method of endoscopically-assisted percutaneous unilateral C1 lateral mass screw and C2 pedicle screw-rod nonfusion fixation for type II odontoid fractures in geriatric patients. A case series design and technical notes. This study took place at Second Affiliated Hospital of Chongqing Medical University. Seven geriatric patients (> 65 years) with type II odontoid fractures and an American Society of Anesthesiologists (ASA) score of 2 or higher received endoscopically-assisted percutaneous unilateral atlantoaxial screw-rod nonfusion fixation. After surgery, all patients were required to wear a rigid collar full-time for 12 weeks. Intraoperative data, the bone union time, American Spinal Injury Association (ASIA) scale scores, Neck Disability Index (NDI) scores, and postoperative complications were collected for assessment.RESULTS The surgical goal was successfully achieved in all patients, 3 of whom had high ASA scores (>= 3) and underwent surgery under local anesthesia. The operative time ranged from 112 to 169 minutes (mean, 131.1 minutes). No neurovascular complications were observed intraoperatively or postoperatively. All patients rapidly returned to their prior level of function and were followed up for 12 to 24 months (average: 16.9 months). Bone union was achieved in all patients. This study is limited by being a retrospective study. Endoscopically-assisted percutaneous unilateral atlantoaxial screw-rod nonfusion fixation is a feasible technique for type II odontoid fractures in geriatric patients. This method offers a compromise between non-operative and operative treatment and allows geriatric patients to rapidly return to their prior level of function. Endoscopically-assisted surgery; geriatric patient; percutaneous atlantoaxial fixation; type II odontoid fracture; unilateral nonfusion fixation.

Postoperative occipital neuralgia in posterior upper cervical spine surgery: a systematic review.

Postoperative occipital neuralgia (PON) after upper cervical spine surgery can cause significant morbidity and may be overlooked. The causes, presentation, diagnosis, management, prognosis, and prevention of PON were reviewed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. English-language studies and case reports published from inception to 2017 were retrieved. Data on surgical procedures, incidence, cause of PON, management, outcomes, and preventive technique were extracted. Sixteen articles, including 591 patients, were selected; 93% of the patients with PON underwent C1 lateral mass screw (C1LMS) fixation, with additional 7% who underwent occipitocervical fusion without C1 fixation. PON had an incidence that ranged from 1 to 35% and was transient in 34%, but persistent in 66%. Five articles explained the possible causes. The primary presentation was constant or paroxysmal burning pain located mainly in the occipital and upper neck area and partially extending to the vertical, retroauricular, retromandibular, and forehead zone. Treatment included medications, nerve block, revision surgery, and nerve stimulation. Two prospective studies compared the effect of C2 nerve root transection on PON. PON in upper cervical spine surgery is a debilitating complication and was most commonly encountered by patients undergoing C1LMS fixation. The etiology of PON is partially clear, and the pain could be persistent and hard to cure. Reducing the incidence of PON can be realized by improving technique. More high-quality prospective studies are needed to define the effect of C2 nerve root transection on PON.

Biomechanical Role of the C1 Lateral Mass Screws in Occipitoatlantoaxial Fixation: A Finite Element Analysis.

Finite element analysis. To determine and compare the construct stability of occipitoatlantoaxial (C0-C1-C2) fixation provided by occipital plate, rod, and screw fixation with or without C1 lateral mass screw (C1LMS). Occipitoatlantoaxial fixation techniques use C2 pedicle screw (C2PS) with and without C1LMS that are then incorporated into occipital plate fixation points using occipital screw. There has, however, been no consensus about the standard occiput to C2 fixation in literature and few reports exist about the effects of additional intervening rigid C1LMS on the biomechanics. The role of biomechanics of the addition of C1LMS in occipitoatlantoaxial fixation for fusion is not known. A nonlinear finite element model (FEM) of the intact upper cervical spine had been developed and validated. Then an FEM of an unstable model treated with occipital plate combined with C2PS and C1LMS fixation (C1LMS + C2PS + plate), was compared to that with C2PS fixation (C2PS + plate). Vertical load of 50 N was applied on the C0, to simulate head weight and 1.5 Nm torque was applied to the C0 to simulate flexion, extension, lateral bending, and axial rotation. Compared with C2PS + plate, the C1LMS + C2PS + plate reduced the range of motion of C0-C2 segment by 3.0%, 35.4%, 29.2%, and 56.9% in flexion, extension, lateral bending, and axial rotation, respectively, and it also led to lower occipital screw and superior rod stresses in all loading conditions. The addition of supplemental C1LMS to occiput-C2 fixation not only enhances greater stability, especially during axial rotation, but also has the capability of distributing the stress evenly and reduces the risk of construct failure because of occipital screw pullout and rod fracture. Therefore, this method may be important to elderly patients with osteopenia or osteoporosis and it may promote a high occipitoatlantoaxial fusion rate. N/A.

Biomechanical Comparison of Modified TARP Technique Versus Modified Goel Technique for the Treatment of Basilar Invagination: A Finite Element Analysis.

A finite element analysis. The aim of this study was to determine the biomechanical differences between atlantoaxial fusion cage combined with transoral atlantoaxial reduction plate fixation (TARP + Cage, modified TARP technique) and that combined with C1 lateral mass screw and C2 pedicle screw fixation (C1LS + C2PS + Cage, modified Goel technique) in the treatment of basilar invagination (BI) by finite element analysis. Clinical studies have shown that transoral anterior atlantoaxial release followed by TARP fixation can achieve reduction, decompression, fixation, and fusion of C1-C2 through a transoral-only approach. Although cage has been used to reduce the BI through posterior approach, there are no studies referred to the cage combined with TARP for C1-C2 fusion. A finite element model was used to investigate and compare the stability between TARP + Cage fixation and C1LS + C2PS + Cage fixation in the treatment of BI. Vertical load of 40 N was applied on the C0, to simulate head weight, and 1.5 Nm torque was applied to the C0 to simulate flexion, extension, lateral bending, and rotation. In comparison with the C1LS + C2PS + Cage model, the TARP + Cage model reduced the ROM by 44.7%, 30.0%, and 10.5% in extension, lateral bending, and axial rotation, while the TARP + Cage model increased the ROM by 30.0% in flexion, and the TARP + Cage model also led to lower screw stress in all motions with one exception (anterior C2PS stress in extension). Our results indicate that the TARP + Cage fixation may offer higher stability to C1LS + C2PS + Cage in extension, lateral bending, and axial rotation but lower stability in flexion. Compared with modified Goel technique, the modified TARP technique not only has the capability of transferring the load and distributing the stress but also can provide neural decompression, stabilization and fusion, and restore C1-C2 normal fusion angle. N/A.

Combined C1-C2 Transarticular with C1 Lateral Mass Screw Fixation for the Treatment of Atlantoaxial Instability: A Single Center Experience

Combined C1-C2 Transarticular with C1 Lateral Mass Screw Fixation for the Treatment of Atlantoaxial Instability: A Single Center Experience

Neurosurgery Concepts: Key perspectives on C2 nerve root transection following C1 lateral mass screw fixation, choroid plexus cauterization in infants with hydrocephalus, quality of life following treatment of vestibular schwannoma, dynamic magnetic resonance imaging for glioblastoma pseudoprogression, cost-utility analysis of lumbar spinal stenosis treatment

Departments of Neurosurgery, George Washington University School of Medicine and Health Sciences, Washington, D.C, 1Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, 2Department of Neurosurgery, University of California Los Angeles, David Geffen School of Medicine, Los Angeles, CA, 3Department of Neurosurgery, Baylor College of Medicine, Texas Children’s Hospital, Houston, TX, USA

C2 nerve dysfunction associated with C1 lateral mass screw fixation.

The C1 lateral mass screw technique is widely used for atlantoaxial fixation. However, C2 nerve dysfunction may occur as a complication of this procedure, compromising the quality of life of affected patients. This is a review of the topic of C2 nerve dysfunction associated with C1 lateral mass screw fixation and related research developments. The C2 nerve root is located in the space bordered superiorly by the posterior arch of C1 , inferiorly by the C2 lamina, anteriorly by the lateral atlantoaxial joint capsule, and posteriorly by the anterior edge of the ligamentum flavum. Some surgeons suggest cutting the C2 nerve root during C1 lateral mass screw placement, whereas others prefer to preserve it. The incidence, clinical manifestations, causes, management, and prevention of C2 nerve dysfunction associated with C(1) lateral mass screw fixation are reviewed. Sacrifice of the C2 nerve root carries a high risk of postoperative numbness, whereas postoperative nerve dysfunction can occur when it has been preserved. Many surgeons have been working hard on minimizing the risk of postoperative C2 nerve dysfunction associated with C1 lateral mass screw fixation.

Ideal screw entry point and optimal trajectory for anterior C1 lateral mass screw: an anatomical study

To explore the ideal screw entry point and optimal trajectory for anterior C1 lateral mass screw internal fixation, and provide an anatomical basis for the technique of anterior C1 lateral mass screw placement. A radiographic analysis of the anatomy of the C1 lateral mass using Computed tomography, CT scan was performed in cervical spine of 56 healthy Chinese adults (28 males, 28 females; mean age, 36.5 years; age range, 18-55 years), by using the Mimics software to reconstruct the 3-D morphology of C1 lateral mass and measuring the inside, middle and outside effective height of the C1 lateral mass in front and back. Measuring the C1 lateral mass safe width with different extraversion angles range from 0° to 30° with a uniform interval of 5°, to find out the ideal extraversion angle. Measuring the range of sagittal angle, to find out the ideal sagittal angle. The inside (H1), middle (H3) and outside (H5) effective height of the C1 lateral mass in front is 6.67 mm, 12.09 mm, and 17.51 mm, the inside (H2), middle (H4) and outside(H6) effective height of the C1 lateral mass in back is 8.17 mm, 13.20 mm, and 18.22 mm. When the extraversion angle choose 0°, 5°, 10°, 15°, 20°, 25°, 30°, and δ, the relative results of safe width (SW) of lateral mass were 4.73 mm, 5.36 mm, 5.90 mm, 6.33 mm, 6.44 mm, 5.70 mm, 4.38 mm, 6.95 mm averagely. The mean distance along the atlas anterior surface between the anterior tubercle and the screw entry point was 12.80 mm, the mean distance from the inferior border of the lateral mass to the screw entry point was 6.87 mm. The range of sagittal angle is 24.22° (-17.74°∼6.48°) . The ideal extraversion angle was 21.14°. The mean distance along the atlas anterior surface between the anterior tubercle and the screw entry point was 12.80 mm. The mean distance from the inferior border of the lateral mass to the screw entry point was 6.87 mm. The ideal sagittal angle is -5.63°. These measurements may facilitate anterior C1 lateral mass screw fixation decreasing the risk of injury to the spinal cord, vertebral artery, and internal carotid artery theoretically. Delineating the individual anatomy in each case with CT scan before surgery is recommended.

Unstable Jefferson fractures: Results of transoral osteosynthesis.

Background:Majority of C1 fractures can be effectively treated conservatively by immobilization or traction unless there is an injury to the transverse ligament. Conservative treatment usually involves a long period of immobilization in a halo-vest. Surgical intervention generally involves fusion, eliminating the motion of the upper cervical spine. We describe the treatment of unstable Jefferson fractures designed to avoid these problems of both conservative and invasive methods.Materials and Methods:A retrospective review of 12 patients with unstable Jefferson fractures treated with transoral osteosynthesis of C1 between July 2008 and December 2011 was performed. A steel plate and C1 lateral mass screw fixation were used to repair the unstable Jefferson fractures. Our study group included eight males and four females with an average age of 33 years (range 23-62 years).Results:Patients were followed up for an average of 16 months after surgery. Range of motion of the cervical spine was by and large physiologic: Average flexion 35° (range 28-40°), average extension 42° (range 30-48°). Lateral bending to the right and left averaged 30° and 28° respectively (range 12-36° and 14-32° respectively). The average postoperative rotation of the atlantoaxial joint, evaluated by functional computed tomography scan was 60° (range 35-72°). Total average lateral displacement of the lateral masses was 7.0 mm before surgery (range 5-12 mm), which improved to 3.5 mm after surgery (range 1-6.5 mm). The total average difference of the atlanto-dens interval in flexion and extension after surgery was 1.0 mm (range 1-3 mm).Conclusions:Transoral osteosynthesis of the anterior ring using C1 lateral mass screws is a viable option for treating unstable Jefferson fractures, which allows maintenance of rotation at the C1-C2 joint and restoration of congruency of the atlanto-occipital and atlantoaxial joints.

The height for screw index (HSI) predicts the development of C2 nerve dysfunction associated with C1 lateral mass screw fixation for atlantoaxial instability

To propose a new measure, the height for screw index (HSI), as a predictor of C2 nerve dysfunction in patients who have received posterior C1 lateral mass screw (C1LMS) fixation for atlantoaxial instability and to examine whether the HSI scores correlated with the development of C2 nerve dysfunction through retrospective analysis of 104 C1LMS inserted in 52 patients with atlantoaxial instability. The medical records of patients who underwent C1LMS fixation were retrospectively reviewed. C1LMS, 3.5mm in diameter, was inserted for atlantoaxial stabilization. The sagittal plane of the planned C1LMS trajectory was reconstructed from CT images. The HSI was defined as the difference in height between C2 ganglion and its corresponding foramen. C2 nerve function was assessed using a validated visual analog scale questionnaire. Each foramen receiving C1LMS was considered as a single unit and patients were categorized to group 1, HSI ≥4.0mm; group 2, HSI <4.0mm. The mean HSI score was 4.7±0.8mm (range 3.1-6.5mm) with 85 (81.7%) units in group 1, and 19 (18.3%) units in group 2. Fourteen (13.5%, 14/104) units developed C2 nerve dysfunction. C2 nerve dysfunction was reported in 4 units in group 1, and 10 units in group 2, respectively. The percentage of C2 nerve dysfunction was significantly higher in group 2 than that in group 1 (P<0.001, Pearson Chi-square test). The HSI score correlates with the development of C2 nerve dysfunction in patients receiving C1LMS fixation for atlantoaxial instability and may be a useful predictor of C2 nerve dysfunction.

Lateral Mass of C1 Fixation and Ponticulus-Posticus

osterior interspinous wiring, with or without halo fixation, was previously themost commonmethod of fusion of C1-2 P and is still very popular. With the increasing adaptation of screw instrumentation for more rigid fixation of the spine, other techniques have become popular. Transarticular C1-2 fusions (Magerlmethod) using a screw to cross the joint supplantedwiring due to improved fusion rates, but carried ahigher risk of injuring the vertebral artery (2). In the modern Goel/Harms technique, using screws in lateral mass of C1 and pars or pedicle of C2 has been increasingly applied due to its robust biomechanical properties and rigid stabilization in various planes (1, 3). One of the major advantages of C1 lateral mass screw fixation has been that the generous size of the lateral mass makes the technique relatively safe.

C2 Nerve Root Transection During C1 Lateral Mass Screw Fixation

Sectioning of the C2 nerve root allows for direct visualization of the C1-2 joint and may facilitate arthrodesis. To determine the clinical and functional consequences of C2 nerve root sectioning during placement of C1 lateral mass screws. All patients undergoing C1 lateral mass screw fixation were included in this prospective study. A standard questionnaire was used to determine the severity of occipital numbness/pain and its effect on quality of life (QOL). Domains of the neck disability index were used to assess the disability related to C2 symptoms. A total of 28 patients were included (C2 transection, 8; C2 preservation, 20). A trend of decreased blood loss and length of surgery was observed in the C2 transection cohort. Occipital numbness was reported by 4 (50.0%) patients after C2 transection. Occipital neuralgia was reported by 7 (35.0%) patients with C2 preservation. None of the patients with numbness after C2 transection reported being "bothered" by it. All patients with occipital neuralgia after C2 sparing reported being "bothered" by it, and 57.1% reported a moderate to severe effect on QOL. The use of medication was reported by 5 (71.4%) patients with neuralgia vs none with numbness. Mean disability was significantly higher with neuralgia vs numbness (P = .016). C2 nerve root transection is associated with increased occipital numbness but this has no effect on patient-reported outcomes and QOL. C2 nerve root preservation can be associated with occipital neuralgia, which has a negative impact on patient disability and QOL. C2 nerve root transection has no negative consequences during C1-2 stabilization.

Posterior Atlantoaxial Fusion Using C1 Lateral Mass and C2 Pedicle by Polyaxial Screw in Atlantoaxial Instability

Objective: The aim of this study is to evaluate clinical and radiological outcomes in subjects of atlantoaxial instability which were operated using C1 lateral mass and C2 pedicle screw (Harmes technique). Materials and Methods: Twenty patients with atlantoaxial instability were scheduled at our clinic for atlantoaxial fusion using polyaxial C1 lateral mass and C2 pedicle screw between January 2008 and March 2014. Results: Trauma was the most common cause of atlantoaxial instability, seen in 18 (90%) patients. Modes of trauma were road traffic accident (75%) and falling (15%). Osteoarthritis was observed in 10% of cases. Patients were followed up with radiographs and clinical examinations. Satisfactory screw placement and reduction were achieved in all patients with the average union time of 3.5 months. There were no implant failures, nonunions, vertebral artery injuries or C2 nerve root injuries. Only, surgical site infections occur in 20% of cases that are improved with medical treatment. Conclusions: C1 lateral mass and C2 pedicle polyaxial screw fixation is an effective technique for the fusion of the atlantoaxial complex. It provides the highest fusion rates without any risk of vertebral injury.

Vertebral Artery Pseudoaneurysm Resulting in Embolic Stroke as a Complication of Posterior C1 Lateral Mass Screw Fixation: A Case Report.

Current literature supports posterior screw instrumentation of the C1 lateral mass as a reliable procedure for treating many occipitocervical and atlantoaxial pathologies with a low incidence of vertebral artery and neurologic injury and a high accuracy rate for screw placement1-6. The rate of vertebral artery injury from Cl lateral mass screw fixation is unknown1,2. Bransford et al. reported no neurologic or vascular complications in a large series, despite cases of suboptimal screw placement2. However, the variable and unique C1 anatomy can make precise instrumentation challenging with the rare potential for vascular and neurologic injury. Iatrogenic vertebral artery injury can have serious consequences, including excessive acute bleeding, arteriovenous fistula, pseudoaneurysm, occlusion, narrowing, or dissection. These defects may remain asymptomatic or lead to massive bleeding, transient ischemic attack, stroke, or death, occurring at variable time intervals up to several years after surgery1,7,8. Vertebral artery occlusion or vertebrobasilar thromboembolic events typically result in brainstem or cerebellar dysfunction7. To the best of our knowledge, this is the first report of a vertebral artery pseudoaneurysm as a complication of posterior C1 lateral mass fixation that resulted in delayed embolic stroke. The patient’s family was informed that data concerning the case would be submitted for publication, and they provided consent. An eighty-two year-old man with a history of a type-II odontoid fracture, which had been treated with a posterior cervical C1-C2 fusion with lateral mass and pedicular fixation 3.5 years ago, presented to our institution after a fall. There had been no reported intraoperative difficulties during the initial surgery. The patient had been neurologically intact both preoperatively and postoperatively. An immediate postoperative computed tomography (CT) scan had demonstrated that the left C1 lateral mass screw had violated the …

C2 Nerve Root Transection during C1 Lateral Mass Screw Fixation: Does it Affect Functionality and Quality of Life?

C2 Nerve Root Transection during C1 Lateral Mass Screw Fixation: Does it Affect Functionality and Quality of Life?

Surgical treatment for chronic atlantoaxial rotatory fixation in children

Six consecutive pediatric patients with chronic atlantoaxial rotatory fixation (AARF) underwent posterior fixation. All patients were first treated conservatively such as with a neck collar, traction, Minerva jacket, or halo-vest; however, they failed to achieve successful reduction because of the C2 facet deformity or C1-2 facet fusion. We performed C1-2 fusion using a C1 lateral mass screw and a C2 pedicle screw, a C1-2 transarticular screw, or an occipitocervical fusion using a rod and wiring system. Five patients achieved solid fusion with no torticollis or neck pain by the final follow-up. One patient had mild torticollis after surgery but no pain. Although we believe that with early diagnosis of AARF and appropriate conservative treatment we can avoid surgery, even with conservative treatment from the onset of symptoms, five patients in our series required surgery because conservative treatment did not lead to successful reduction. When conservative treatment for chronic AARF patients fails, C1-2 transarticular fixation, and C1 lateral mass screw and C2 pedicle screw fixation are reliable methods to treat these patients.