Cervical Fixation Research Articles

Posterior C2 Fixation Using Trans-C2 Inferior Articular Process Screws: A Case Series and Technical Note

Upper cervical fixation with C2 pedicle screw insertion may predispose patients to vertebral artery injury, in particular, patients with craniovertebral junction anomalies. The aim of this study was to describe an alternative technique with trans-C2 inferior articular process screw (C2IAPS) insertion for rigid C2 fixation, which can be used to anchor the C2 vertebra for upper cervical fixation. Records of 19 patients who underwent posterior atlantoaxial fixation using C2IAPS combined with C1 lateral mass screw were retrospectively reviewed. Efficacy was assessed by postoperative imaging and Japanese Orthopaedic Association scores. There were 22 C2IAPSs successfully implanted (3 on both sides and 16 on 1 side). With the exception of 2 screws that had intruded into the outlet of the intervertebral foramen, all screws were safely implanted. Average Japanese Orthopaedic Association scores improved from 11.8 ± 1.9 preoperatively to 15.3 ± 1.3 postoperatively. Bony fusion rate was 100%. For patients who are not eligible for C2 pedicle screw fixation, C2IAPS fixation can be considered as an alternative technique for upper cervical fixation of C2.

Minimally Invasive Spinal Surgery: How to Keep out of Trouble

Innovative techniques have revolutionized minimally invasive surgeries, which has significant benefits for the patients. Despite the benefits, these advancements require a longer learning curve for an inexperienced surgeon. The authors have collected some pearls from their experience and from other surgeons. Tips and tricks about common MISS procedures such as minimally invasive endoscopic transforaminal lumbar disc and interlaminar discectomy, MIS, TLIF, LLIF, ALIF, spinal tumor excision, posterior cervical fixation and foraminotomy are described. How to stay out of trouble is explained with these surgeries. These techniques will help young surgeons to become proficient and achieve better outcome.

Cervical laminectomy and micro resection of the posterior venous plexus in Hirayama disease

IntroductionHirayama disease is a rare cervical myelopathy predominantly affecting young adults and mainly found in Asia. It results in a pure motor distal lesion of the upper limbs with slow progression. Dynamic magnetic resonance imaging (MRI), which allows the diagnosis to be made, shows a typical appearance of anterior compression of the cervical spinal cord associated with enlargement of the posterior epidural spaces due to a dilated venous plexus. Surgery is considered when conservative treatment has failed. However, the type of surgery is not well standardized in this compressive myelopathy. MethodsWe report on three patients with Hirayama disease operated using an original method: cervical decompressive laminectomy and coagulation of the posterior epidural plexus without fixation. The clinical, radiological and surgical data of these three patients were analyzed. Each patient underwent postoperative MR imaging. ResultsThe mean age at diagnosis was 18.6 years (16–20 years) with a history of progressive symptoms lasting 1 to 4 years before treatment. Follow-up was 21 to 66 months after surgery. Neurological and electrophysiological improvement was noted in two patients; the third had stabilized. Postoperative MRI confirmed normalization of flexion imaging on MRI. None of the three patients complained of disabling neck pain. ConclusionPosterior cervical decompression with coagulation of epidural venous plexus is a technique that seems effective in Hirayama disease in young subjects. It effectively treats patients by avoiding permanent cervical fixation.

Risk Analysis Based on the Timing of Tracheostomy Procedures in Patients with Spinal Cord Injury Requiring Cervical Spine Surgery

To determine the optimal moment to perform tracheostomy in a patient requiring anterior cervical fixation. A retrospective observational study conducted over an 18-year period included 56 patients who had been admitted to the intensive care unit with acute spinal cord injury and underwent tracheostomy and surgical fixation. The sample was divided into 2 groups: at-risk group (31 patients who had undergone tracheostomy before cervical surgery or <4 days after surgery) and not-at-risk group (25 patients who had undergone tracheostomy >4 days after fixation surgery). Descriptive and comparative studies were carried out. Overall trend of the collected data was analyzed using cubic splines (graphic methods). The only infectious complications diagnosed as related to the surgical procedure were infection of the surgical wound in 2 patients in the not-at-risk group (12%) and deep tissue infection in 1 patient in the at-risk group (3.2%). During the study period, we identified a tendency toward performance of early tracheostomies. Our results suggest that the presence of a tracheostomy stoma before or immediately after surgery is associated with a low risk of infection of thecervical surgical wound in instrumented spinal fusion.

Management of C4-C5 Fracture with Approach 360⁰ without the Spinal Instrumentation.

Introduction: Usually, cervical pedicle screw fixation has been considered too risky for neurovascular structures. The purpose of this case report is to present a young male patient who suffered a C4-C5 fracture after a motor vehicle accident treated with a 360⁰surgical approach without spinal instrumen-tation.&#x0D; Case report: A young male patient suffered a motor vehicle accident driving the vehicle without seat belt. Instantly after the accident he reports about severe neck pain, inability to move his left extremi-ties, difficulty moving his right extremities, burning pain. All patients had various degrees of cord injury, and they were classified according to the American Spinal Cord Injury Association (ASIA) Impairment Scale and Denis classification.&#x0D; Results: We present this young patient, where the selected surgical approach without using spinal instrumentation resulted has favorable outcome.&#x0D; Conclusion: Surgical options regarding to cervical spine fractures include stabilization and decompres-sion with and without spinal instrumentation. Carefully selected cases may be treated safely without instrumentation avoiding potential complications of spinal instrumentation such pseudoarthrosis, in-strumentation failure, infection, etc.

Penetration of components of cervical fixation device into esophagus: An unexpected finding for the endoscopist.

Penetration of components of cervical fixation device into esophagus: An unexpected finding for the endoscopist.

Airway management in morbidly obese with cervical instability using awake insertion of supra glottic device and Aintree intubation catheter

We report airway management of a morbidly obese with possible difficult mask ventilation and previous cervical fixation, posted for bariatric surgery under general anesthesia. We achieved insertion of the supra glottic device (SGD ) under conscious sedation. Endotracheal intubation was further facilitated using Aintree intubation catheter (AIC) and flexible endoscope assisted intubation via the SGD. Consent from the patient and the IEC approval was obtained prior topublication. We reviewed evidence-based anaesthetic concerns and described our airway management. Our aim was to maintaining continuous oxygenation and achieve a secure airway with minimal neck move-ment. This further guides anesthesia practitioners caring for the obese patients withanticipated difficulty in mask ventilation and additionalrisks and need for continuous oxygenation. Keywords: Obese, bariatric, difficult airway, mask ventilation, BMI, neck circumference, Aintree, Cervical instability

Craniovertebral fixation … a new technique of occipital – cervical fixation

Background: Craniovertebral instability following transoral odontoid excision is usually treated by posterior occipital–cervical fixation using occipital plate and cervical lateral mass fixation with screw rod construct. A patient previously operated for basilar invagination had postoperative infection of both the transoral wound and the posterior implant site which needed removal of the posterior implant earlier.Clinical presentation: The patient presented with severe neck pain, myelopathy, and chronic discharging sinus in the posterior lower aspect the previous neck surgery wound. Reimaging revealed incomplete odontoid excision. He underwent repeat transoral odontoid excision. Treatment of the instability needed occipitocervical fixation avoiding, the atlas, axis (weakened by infection and previous implants), and the infected posterior cervical wound. A new technique using a customized plate rod construct, fixed anteriorly to the mid cervical vertebrae (by a standard mid cervical exposure) with the rods contoured to reach posteriorly through the safe paraspinal corridor and connected with domino connectors to occipital plate rods fixed on either side of midline by additional posterior exposure avoiding the midline scar was planned and executed successfully.Conclusion: This construct transfers the weight of the cranium to the cervical vertebral bodies along the physiological line of weight transmission and can be considered for distraction and reduction of basilar invagination with atlantoaxial dislocation. The technique seems to be safe and reproducible, but will need to tested over time with more cases.

181 Comparing the Efficacy of Long Segment Subaxial Cervical Fixation Ending at Either C7 or the Upper Thoracic Spine in the Treatment of Cervical Degenerative Disease

Abstract INTRODUCTION The cervicothoracic junction comprises C7 to T3 and has unique anatomical and biomechanical properties. multi-level subaxial cervical fixation usually continues to T1 or T2 in order to keep the cervicothoracic junction stable. However, this long segment fixation has disadvantages.Our study focus on degeneration of the C7-T1 level after long segment subaxial cervical fixation and fusion stopping at C7. METHODS Included were patients with cervical degenerative disease who underwent posterior cervical fusion and fixation from 2009–2015. All complications were captured. Postoperative X-ray and CT confirmed fusion at six and twelve months after surgery. X-ray and CT confirmed screw loosening, misplacement, pull-out, breakage, or rod breakage. RESULTS &gt;Of the 174 patients reviewed, 83 underwent cervical laminectomy and fixation that stopped at C7.C7-T1 sagittal Cobb angle was measures and no significant change was found between the preoperative and one-year postoperative follow-up. No spondylolisthesis was seen, and postoperative cervical MRI did not show signal changes at this level. The complication rate was low. CONCLUSION Posterior cervical spine fixation and fusion stopping at C7 can correct and maintain cervical sagittal parameters, and does not result in acceleration of C7-T1 degeneration.

Intraoperative Navigation Is Associated with Reduced Blood Loss During C1-C2 Posterior Cervical Fixation.

Traumatic injuries, degenerative/rheumatologic conditions, tumors, or infections of the upper cervical spine may in certain circumstances require surgical stabilization. C1 lateral mass screws (Harms technique) in combination with C2 instrumentation (pars, pedicle, translaminar screws) have become a mainstay of surgical treatment. The surgical anatomy of the C1 lateral mass can be challenging especially with the robust venous plexus that often causes significant bleeding with exposure of the C1-C2 articular complex. The purpose of this study was to examine whether the use of navigation reduced intraoperative blood loss during atlantoaxial fixation. We reviewed our institutional experience with atlantoaxial instrumentation with and without navigation from 2007 to 2016. We limited our cases to those requiring C1-C2 stabilization in traumatic and degenerative cases and not as part of more extensive surgical stabilizations. We identified 45 consecutive patients and compared intraoperative blood loss, need for transfusion, and time of procedure with and without the use of navigation. There was a significant reduction in the amount of intraoperative blood loss in the navigated (n=20) versus non-navigated cases (n= 25). In addition, although the navigated cases initially were longer, currently there is no significant difference in the length of the cases. In our series, surgical navigation significantly reduced blood loss compared with non-navigated cases without increasing surgical time or risk of complication. Furthermore, navigation has the potential to reduce operative times due to a reduction in blood loss.

Misplaced Cervical Screws Requiring Reoperation.

Study Design:A multicenter, retrospective case series.Objective:In the past several years, screw fixation of the cervical spine has become commonplace. For the most part, this is a safe, low-risk procedure. While rare, screw backout or misplaced screws can lead to morbidity and increased costs. We report our experiences with this uncommon complication.Methods:A multicenter, retrospective case series was undertaken at 23 institutions in the United States. Patients were included who underwent cervical spine surgery from January 1, 2005, to December 31, 2011, and had misplacement of screws requiring reoperation. Institutional review board approval was obtained at all participating institutions, and detailed records were sent to a central data center.Results:A total of 12 903 patients met the inclusion criteria and were analyzed. There were 11 instances of screw backout requiring reoperation, for an incidence of 0.085%. There were 7 posterior procedures. Importantly, there were no changes in the health-related quality-of-life metrics due to this complication. There were no new neurologic deficits; a patient most often presented with pain, and misplacement was diagnosed on plain X-ray or computed tomography scan. The most common location for screw backout was C6 (36%).Conclusions:This study represents the largest series to tabulate the incidence of misplacement of screws following cervical spine surgery, which led to revision procedures. The data suggest this is a rare event, despite the widespread use of cervical fixation. Patients suffering this complication can require revision, but do not usually suffer neurologic sequelae. These patients have increased cost of care. Meticulous technique and thorough knowledge of the relevant anatomy are the best means of preventing this complication.

Surgical treatment for fracture-dislocation of upper cervical spine complicated with vertebral artery injury

Objective To explore the perioperative management and surgical outcomes of fracture-dislocation of the upper cervical spine complicated with vertebral artery injury. Methods We ret-rospectively analyzed the clinical data of 19 patients diagnosed with fracture-dislocation of the upper cervical spine complicated with vertebral artery injury who had been treated at our department from January 2008 through December 2012. They were 14 males and 5 females, aged from 22 to 53 years (mean, 35.2 years). All the patients had fractures of the atlas and/or axis, and disordered atlanto-axial relationship as well. According to Frankel grading system, 8 cases were Grade D and 11 Grade E. The cervical posterior fixation with pedicle screws was adopted for all and hemostasis was conducted for those with bleeding from the broken vertebral artery. Their Frankel grade, Japanese Orthopedic Association (JOA) score and visual analogue scale (VAS) score were compared between preoperation and final follow-up. Results Intraoperative hemor-rhage occurred in 2 patients from the injured vertebral artery. Hemostasis was achieved through direct tamponade with bone wax and gelatin sponge in one and through endovascular intervention after bleeding control by direct tamponade in another. Neither of them presented with symptoms of posterior circulation ischemia after operation. The mean operation time was 153.5 min, and the mean blood loss was 542.1 mL. All the patients were followed up for an average time of 28 months. Bony union was obtained in all after an average time of 13.5 weeks. Follow-ups revealed no ischemic stroke in this series. Symptoms of transient ischemic attack, like transient dizziness and blurred vision, appeared in 2 patients. At the final follow-up, all the patients were assessed as Frankel Grade E. Their mean JOA and VAS scores were significantly improved from 8.1±1.2 and 7.0±1.7 preoperatively to 12.7±1.6 and 1.3±1.2, respectively (P< 0.05). Conclusions An-giography examination is routinely indicated for the patients with fracture-dislocation of the upper cervical spine perioperatively. Preoperative evaluation of the vertebral artery and its adjacent structures and effective intra-operative hemostasis can avoid uncontrollable bleeding during operation, reduce postoperative complications, and improve surgical outcomes. Key words: Cervical; Fractures, bone; Dislocation; Vertebral artery injury

A Novel Patient-Specific Drill Guide Template for Pedicle Screw Insertion into the Subaxial Cervical Spine Utilizing Stereolithographic Modelling: An In Vitro Study.

Study DesignCadaveric study.PurposeThe purpose of this study was to assess the accuracy and feasibility of cervical pedicle screw (CPS) insertion into the subaxial cervical spine placed using a patient-specific drill guide template constructed from a stereolithographic model.Overview of LiteratureCPS fixation is an invaluable tool for posterior cervical fixation because of its biomechanical advantages. The major drawback is its narrow corridor that allows very little clearance for neural and vascular injuries.MethodsFifty subaxial pedicles of the cervical vertebrae from five cadavers were scanned into thin slices using computed tomography (CT). Digital imaging and communications in medicine images of the cadaver spine were digitally processed and printed to scale as a three-dimensional (3D) model. Drill guide templates were manually moulded over the 3D-printed models incorporating pins inserted in the pedicles. The drill guide templates were used for precise placement of the drill holes in the pedicles of cadaveric specimens for pedicle screw fixation.ResultsThe instrumented cadaveric spines were subjected to CT to assess the accuracy of our pedicle placement by an external observer. Our patient-specific drill guide template had an accuracy of 94%.ConclusionsThe use of a patient-specific drill guide constructed using stereolithography improved the accuracy of CPS placement in a cadaveric model.

A rare case of pharyngeal perforation and expectoration of an entire anterior cervical fixation construct

Anterior cervical discectomy and fusion (ACDF) is a very common surgery performed globally. Although a few cases of expectorating screws or extrusion of screws into the gastrointestinal tract through esophageal perforations have previously been reported, there has not been a case reporting pharyngeal perforation and entire cervical construct extrusion in the literature to date. In this report the authors present the first case involving the extrusion of an entire cervical construct via a tear in the posterior pharyngeal wall. An 81-year-old woman presented to the emergency department (ED) with a complaint of significant cervical pain 5 days after a fall due to a syncopal event. Radiological findings showed severe anterior subluxation of C-2 on C-3 with no spinal cord signal change noted. She underwent ACDF at the C2-3 level utilizing a polyetheretherketone (PEEK) cage, allograft, autograft, and a nontranslational plate with a locking apparatus and expanding screws. The screw placement was satisfactory on postoperative radiography and the Grade II spondylolisthesis of C-2 on C-3 was reduced appropriately with the surgery. The postoperative radiographs obtained demonstrated good instrumentation placement. Three and a half years later the patient returned to the ED having expectorated the entire anterior cervical construct. A CT scan demonstrated the C-2 and C-3 vertebral bodies to be fused posteriorly with an anterior erosive defect within the vertebral bodies and the anterior fusion hardware at the C2-3 level no longer identified. The fiberoptic laryngoscopy demonstrated a 1 × 1 cm area over the importation of the hypopharynx, above the glotic area. The Gastrografin swallowing test ruled out any esophageal tear or fistula and confirmed the presence of a large ulcer on the posterior wall of the oropharynx. To the best of the authors' knowledge, this is the first ever reported case of a tear in the posterior pharyngeal wall along with extrusion of the entire cervical construct after ACDF. This case demonstrates a rare but potentially serious complication of ACDF. Based on the available literature, each case requires separate and distinct treatment from the others.

Anterior Spinal Stabilization and Fusion in Cervical Spinal Trauma

Objective: It was to find out the efficacy and benefits of anterior cervical spinal stabilization procedu-res in cases of cervical trauma.Material and Methods: It is a prospective study of 30 cases of Cervical Spinal Trauma in which anterior cervical spinal stabilization and fusion was performed. Study span is three years i.e from July 2005 to June 2008 with follow up period of one year and it was carried out in the Department of Neurosurgery, Quaid-e-Azam Medical College / Bahawal Victoria Hospital Bahawalpur.Results: 30 cases of cervical spinal trauma were included in the this study. Age range was 15 years to 40 years. Twenty three (23) were males and seven (7)) were females with male to female ratio of 3.2:1. Most common cause of cervical spinal injury was road traffic accidents and most common site of traumatic involvement was C5/C6 cervical spinal level. All the patients were belonging to poor and middle socio-economic class. Nine (9) patients sustained complete cervical cord injury and they were quadriplegic and remaining twenty one (21) patients were quadripretic as a result of partial cervical cord injury. All patients were assessed clinically and radiologically. Plain X-rays of cervical spine, AP and LAT. views, C-T scan and MRI of cervical spine were obtained to get information of injuries in detail. In almost all the cases, anterior two columns of spine were disrupted resulting in instability and cord compression. In all the cases cervical traction was applied to get alignment of the cervical column first and then anterior fixation and fusion was performed. All patients were mobilized early after surgery.Outcome: Nine (9) cases with complete cord injury did not improve neurologically after surgery. Eleven (11) patients with partial cord injury and power of G 3/5 before surgery improved to G 4+/5 after surgery and ten (10) patients with power G 2/5 before surgery improve to G 3/5 after surgery. All patients were out of bed early, to prevent the complications of being and ridden for long time.Conclusion: Anterior cervical spinal fixation and fusion is an excellent way of cervical spinal stabilization in cases of cervical trauma. Patients improve Neurologically with these procedures and they are mobilized early from the beds to prevent complications of being bed ridden for longer periods of time.

Posterior cervical screw fixation in children: the treatment experience

Objective. To prove the safety and technical and mechanical validity of posterior screw fixation of the cervical spine in children and to compare different types of the cervical spine fixation based on our own treatment experience and literature data. Material and Methods . A retrospective analysis of 47 patients under the age of 18 years who underwent various types of posterior instrumental fixation of the cervical spine was performed. Level of Evidence – III. Results . The duration of postoperative follow-up varied from 2 months to 6.6 years (mean, 2.1 ± 1.6 years). A total of 186 screws were placed, the number of screws inserted in one patient reached 10 (mean, 3.9 ± 2.4). Postoperative complications were observed in 5 (10.6 %) patients. Conclusion . Posterior screw fixation of the cervical spine provides biomechanically reliable stabilization of the segment, helps to achieve good correction of deformity and reduction of dislocations, shortens the period of rehabilitation, and is a safe method of surgical treatment in children.

Efficacy and safety of a digital navigation template combined with cervical pedicle screw implantation: study protocol for a prospective, single-center, self-controlled, clinical trial

Background and objectives: Cervical pedicle screw fixation is a reliable method for the treatment of traumatic and non-traumatic cervical instability and cervical disc removal and fixation; however, the operation risks and the failure rate of screw insertion are still high. At present, the digital navigation template with digital computer technology, used in the department of orthopedics, has the advantages of accurate screw insertion and a small error in the screw insertion depth. This trial aims to observe the clinical efficacy and safety of the digital navigation template combined with cervical pedicle screw implantation. Design: This is a prospective, single-center, self-controlled, clinical trial. Methods: Thirty-two patients with cervical spondylosis will be recruited from the Harrison International Peace Hospital, Hebei Province, China. Before surgery, a three-dimensional (3D) navigation model of the cervical vertebrae will be designed by 3D reconstruction. The navigation template will be generated by 3D printing. The cervical pedicle screws will be implanted according to preoperatively designed models and the screw positions will be observed by computerized tomography (CT) after surgery. The patients will be followed up for 40 months. Outcome measures: The primary outcome measure is the excellent and good rate of screw position 40 months after implantation. The secondary outcome measures include the Visual Analog Scale score, American Spinal Injury Association classification, cervical X-ray and CT images before implantation and 40 months after implantation, and the incidence of adverse reactions 40 months after implantation. Discussion: We will verify a high success rate of cervical pedicle screw implantation using the digital navigation template. The operation is simple and quick, with good efficacy and safety. Ethics and dissemination: The protocols have been approved by the Ethics Committee of the Harrison International Peace Hospital in China (approval number: 20120630). The study protocol has been conducted in accordance with the Declaration of Helsinki, formulated by the World Medical Association. Written informed consent will be obtained from all participants. The recruitment of subjects will begin in December 2017. Samples and data will be collected from December 2017 to April 2019. Outcome measures will be analyzed in October 2020. This trial will be completed in November 2020. The results of the trial will be reported in a scientific conference or disseminated in a peer-reviewed journal. Trial registration: This trial has been registered in the Chinese Clinical Trial Registry (registration number: ChiCTR-ONC-17013481).

CT Evaluations for C2 Pedicle Screw Fixation: Multiplanar Computerized Tomography Measurements in 100 Moroccan Patients

Abstract Background: Transpedicular screw fixation in the Axis is difficult due to its relation with adjacent anatomic features. Successful placement requires a sufficient understanding of axis pedicle. Objective: The aim was to assess length and width of the C2 pedicle in Moroccan population in order to evaluate the safety of pedicle screw fixation. Patients and methods: We evaluated the C2 pedicle morphology using computed tomography (CT) imaging in 100 patients (30 females and 70 males; age range, 18–70; mean, 36,2 ± 11,9 years). Axial CT cutting was made at 1.25 mm intervals. The measurements of C2 pedicles were performed on CT images using its measurement tools. The pedicle transverse width was defined as the mediolateral diameter of the pedicle isthmus. Pedicle length (distance from the posterior cortex of the lateral mass to the middle of the vertebral body). Results: The overall mean pedicle transverse widths (PTW) were 5.3 mm (4.1 to 7.1 mm), in males were 5.2 ± 0.5 mm and 5 ± 0.4 mm in females. The overall mean pedicle lengths (PL) were ranged from 19,7 to 26.7 mm with average 22.5 mm. The mean PL in female was 21.8 ± 1.4 mm and 22.8 ± 1.7 mm in male. The mean PTW and PL were greater in males than in females at both sides, and this difference was statistically significant. On the other hand, they were not correlated to age in our adult patients. Conclusion: Our findings suggest that there were significant differences between individuals and ethnics. The preoperative CT scans undergoing cervical transpedicular fixation should be thoroughly analyzed for successful pedicle screws placement.

A Nearly Lethal Screw: An Unusual Cause of Recurrent Bradycardia and Asystole Episodes after Fixation of the Cervical Spine

We present a case of a 51-year-old man who was injured in a bicycle accident. His main injury was an unstable fracture of the cervical and thoracic vertebral column. Several hours after his arrival to the hospital the patient underwent open reduction and internal fixation (ORIF) of the cervical and thoracic spine. The patient was hospitalized in our critical care unit for 99 days. During this time patient had several episodes of severe bradycardia and asystole; some were short with spontaneous return to sinus and some required pharmacological treatment and even Cardiopulmonary Resuscitation (CPR). Initially, these episodes were attributed to the high cervical spine injury, but, later on, CT scan suggested that a fixation screw abutted on the esophagus and activated the vagus nerve by direct pressure. After repositioning of the cervical fixation, the bradycardia and asystole episodes were no longer observed and the patient was released to a rehabilitation ward. This case is presented in order to alert practitioners to the possibility that, after operative fixation of cervical spine injuries, recurrent episodes of bradyarrhythmia can be caused by incorrect placement of the fixation screws and might be confused with the natural history of the high cervical cord injury.

C1-C2 Posterior Cervical Fixation by a Harms Technique Modification

C1-C2 Posterior Cervical Fixation by a Harms Technique Modification