Posterior C1-C2 fusion for atlantoaxial rotatory fixation after posterior fossa craniotomy in a 4-year old: a case report.

INTRODUCTION: This study aimed to highlight that atlantoaxial rotatory fixation (AARF) can be related to neurosurgery procedures in children, with an afterward demonstration of good results after halo-gravity traction and C1-C2 stabilization using the Harms technique. CASE DESCRIPTION: To the best of our knowledge, this is the first case to report a 4-year-old boy who presented with AARF after a posterior fossa craniotomy to treat a cerebellar astrocytoma. At our medical facility, AARF was diagnosed using plain radiography and computed tomography imaging. The patient was treated with continuous cranial traction for 14 days. Initially, we detected that the patient had no C1 posterior arch or C2 spinous process; therefore, the best option was to perform the Harms technique. Postoperatively, the patient was placed in a cervical collar for 4 weeks. At the 4-year postoperative follow-up, the patient was doing well and had not developed any complications. CONCLUSION: Herein, we report a case in which AARF can be developed after neurosurgical procedure. Surgical techniques used for atlantoaxial subluxation should be carefully selected. In our case, the Harms technique after cranial traction was an excellent option for correcting and stabilizing the abnormal neck position. However, further studies are required to determine the best technique to use in the pediatric population.

Nuance in Craniovertebral Junction Surgical Approach for Posterior C1-C2 Harms Stabilization: "Window Transposition" of the External Vertebral Venous Plexus for Bloodless C1 Lateral Mass Screw Insertion: Anatomical Aspects and Technical Notes.

Atlas and axis instrumentation may be necessary in cases of several craniocervical junction pathologies. According to the Harms technique, C1-C2 polyaxial screws are inserted respectively in the C1 lateral masses and in C2 pedicles. C1 lateral mass screw insertion requires the careful subperiosteal dissection of the posterior elements of C1, the identification of the screw entry point by the downward distraction of C2 nerve root, and the cautious sparing of the overlying posterior external vertebral venous plexus (peVVP), whose bleeding, obstructing the surgical field, is sometimes barely controlled by hemostatic agents and swabbing. The authors describe in detail the anatomical aspects of an alternative surgical technique developed for the microsurgical transposition of the C1-C2 interposed external vertebral venous plexus in the case of Harms C1-C2 screw stabilization. The longitudinal median incision of the atlantoaxial membrane, followed by bilateral subperiosteal dissection and microsurgical section respectively at the inferior borders of the C1 laminae and at the superior borders of the C2 laminae, allows, as a "window opening," the symmetrical mediolateral transposition of the peVVP. This procedure provides a faster and cleaner anatomical exposition of the posterior surface of the C1 lateral mass and the C2 isthmus, preventing troublesome intraoperative venous bleeding that hinders C1 lateral mass screw insertion.

Posterior atlantoaxial internal fixation using Harms technique assisted by 3D-based navigation robot for treatment of atlantoaxial instability.

BACKGROUND: To evaluate the accuracy of screw placement using the TiRobot surgical robot in the Harms procedure and to assess the clinical outcomes of this technique. METHODS: This retrospective study included 21 patients with atlantoaxial instability treated by posterior atlantoaxial internal fixation (Harms procedure) using the TiRobot surgical robot between March 2016 and June 2021. The precision of screw placement, perioperative parameters and clinical outcomes were recorded. Screw placement was assessed based on intraoperative guiding pin accuracy measurements on intraoperative C-arm cone-beam computed tomography (CT) images using overlay technology and the incidence of screw encroachment identified on CT images. RESULTS: Among the 21 patients, the mean age was 44.8 years, and the causes of atlantoaxial instability were os odontoideum (n = 11), rheumatoid arthritis (n = 2), unknown pathogenesis (n = 3), and type II odontoid fracture (n = 5). A total of 82 screws were inserted with robotic assistance. From intraoperative guiding pin accuracy measurements, the average translational and angular deviations were 1.52 ± 0.35 mm (range 1.14-2.25 mm) and 2.25° ± 0.45° (range 1.73°-3.20º), respectively. Screw placement was graded as A for 80.5% of screws, B for 15.9%, and C for 3.7%. No complications related to screw misplacement were observed. After the 1-year follow-up, all patients with a neurological deficit experienced neurological improvement based on Nurick Myelopathy Scale scores, and all patients with preoperative neck pain reported improvement based on Visual Analog Scale scores. CONCLUSIONS: Posterior atlantoaxial internal fixation using the Harms technique assisted by a 3D-based navigation robot is safe, accurate, and effective for treating atlantoaxial instability.

Unilateral facet cyst at the atlantoaxial joint leading to cervical myelopathy: A case report and review of literature.

Background: Spinal synovial cysts are rare in the cervical spine where they may cause myeloradiculopathy. Contrast MR studies help differentiate these from other lesions. The optimal treatment is often surgical removal. Case Description: A 47-year-old male presented with axial neck pain, numbness, and left-hand paresthesia. When the MR study showed dorsolateral cord compression due to a left-sided C1-C2 facet cyst, he underwent a unilateral decompression/fusion. Adequate cyst removal/excision was documented on a postoperative MR performed 2 weeks and 3 months postoperatively. Conclusion: A 47-year-old male presented with myelopathy attributed to an MR-documented dorsolateral C1/ C2 facet cyst. Following excision/decompression of the cyst and posterior fusion, the patient's symptoms/signs resolved.

Efficacy and Safety of Goel-Harms Technique in Upper Cervical Spine Surgery: A Systematic Review and Meta-Analysis.

OBJECTIVE: The main purpose of this systematic review and meta-analysis was to estimate the incidence of implant-associated complications and fusion rates for the Goel-Harms technique (GHT) and to show potential factors affecting the complications and nonunion development. METHODS: A systematic search of the PubMed database according to PRISMA guidance was performed. The main inclusion criteria comprised description of fusion rate and/or implant-associated complications rate. RESULTS: This systematic review included 86 articles focused on the results of surgery in 4208 patients. The rate of screw-related complications was as follows: 1) vertebral artery (VA) injury, 2.8%; 2) screw malposition in the direction of the VA, 5.8%; and 3) C2 nerve root irritation, 6.1%. The nonunion rate was 4.2%. Transpedicular screw insertion to the C1 and C2 vertebrae were the safest regarding VA injury and correlated with lower blood loss. For C1-C2 fusion, there was no statistical difference for the different bone graft localization. C2 nerve root irritation rate did not depend on screw insertion technique. The use of a freehand technique did not correlate with a high rate of screw-related complications. CONCLUSIONS: The Goel-Harms technique is a promising method of C1-C2 fusion, with a relatively low nonunion and VA injury rate. It can be performed safely without C-arm or navigation system assistance. Transpedicular screw insertion trajectories to the C1 and C2 vertebrae were safest regarding VA injury and blood loss volume. Further comparative studies of various C1-C2 stabilization methods with a high level of significance should be carried out to identify the optimal approach.

Intraoperative Computed Tomography for C1-C2 Stabilization by Goel-Harms: Analysis of Clinical Efficacy and a Novel Classification of Screw Placement Accuracy.

BACKGROUND: The introduction of intraoperative computed tomography (iCT) could improve the surgical results of C1-C2 stabilization by Goel-Harms, especially in patients with complex deformities. This study aims to investigate the impact of iCT on the accuracy of C1-C2 screw positioning and to develop a score based on multiparametric analysis of imaging data (Cervical Screw Placement Accuracy score [CSPAs]). METHODS: Twenty-one patients were retrospectively evaluated. The data obtained with the use of an iCT were compared with the incidence of cases of malpositioning in the literature. Multiparametric imaging criteria were developed: the 82 screw positions were evaluated using the CSPA criteria and 2 additional variables. The CSPAs was obtained from the aggregation of the CSPAs criteria: optimal (CSPAs ≥8), suboptimal (CSPAs = 6-7), malpositioned (CSPAs ≤5). RESULTS: The average incidence of malpositioning in C1-C2 arthrodesis decreased from 13% without iCT to 1.2% with the aid of iCT, considering a monoparametric value. The CSPAs analysis shows a greater discretion and higher number of well-defined categories of the accuracy of C1-C2 screw position: optimal, 80.3%; suboptimal, 17.1%; and malposition, 2.6%. A correlation was observed between the accuracy of the positioning of both right and left screws in C2. Furthermore, the anatomic site of C2 screws was found to be a predictor of cortical invasion. CONCLUSIONS: The results suggest that the introduction of the iCT is associated with a consistent improvement of the accuracy in the positioning of the screws. A multiparametric score (CSPAs) could improve the assessment of screw placement.

Case report: Minimally invasive modification of the Goel-Harms atlantoaxial fusion utilizing percutaneous screws and intra-articular cage is feasible and results in decreased blood loss.

Treatment of atlantoaxial pathology is often associated with significant morbidity and mortality. While surgical techniques for fixation are well established, approaches that minimize blood loss and muscle dissection are advantageous for expediting recovering and minimizing surgical risk. We present a 34-year-old female who presented with a Type III odontoid fracture requiring surgical fixation. She underwent a C1-2 fusion employing a novel minimally invasive modification of the Goel-Harms atlantoaxial fusion using percutaneous screws and intra-articular cage.

An experience with Goel-Harms C1-C2 fixation for type II odontoid fractures.

Objective: Type II odontoid fractures need surgical stabilization for disabling neck pain and instability. Anterior odontoid screw fixation is a well-known technique. However, certain patients require posterior fixation. We present our surgical results and experiences with nine cases managed by the Goel-Harms technique. Materials and Methods: This is a retrospective review of nine patients operated on between January 2019 and December 2021 for Type II odontoid fractures with posterior fixation technique. Their clinical profile was collected from case files. The radiological data were retrieved from radiology archives. The indications for surgery were instability and refractory neck pain. The surgical decision for posterior fixation was guided by fracture morphology. Results: The mean age of presentation was 37.22 ± 9.85 years. Seven patients had Type II, and two had Type IIa odontoid fracture. All patients presented with unbearable neck pain. One patient had a quadriparesis. The fracture line was anterior-inferior sloping in six, posterior-inferior sloping in two, and transverse in one case. The anterior-posterior displacement of fracture ranged from 0 to 7 mm (mean 2.44 ± 2.18 mm). Partial transverse ligament tear without the Atlanto Axial Dislocation was present in three patients. The C1-C2 joint distraction was required in five cases. C1-C2 joint spacer was required in two cases. Following surgery, neck pain was relieved in all cases. Complete fracture alignment was achieved in eight patients. There were no postoperative complications. At the mean follow-up of 16.22 ± 9.61 months, there was no implant failure. Conclusions: Posterior C1-C2 fixation by the Goel-Harms technique is an excellent alternative to anterior fixation in selected cases.

Dynamic cervical flexion/extension atlantodental interval and functional outcome of the Harms technique for posterior C1/2 fixation: A retrospective analysis of 16 atlantoaxial subluxation cases in a tertiary medical center.

BACKGROUND: The aim of this study was to assess the relationship between the atlantodental interval (ADI) on dynamic flexion/extension cervical radiographs and functional outcomes of posterior spinal fixation by the Harms technique for atlantoaxial subluxation (AAS). Dynamic flexion/extension on cervical radiographs is a standard assessment for evaluation of C1/2 instability in AAS patients. Most studies focused on postoperative ADI and functional outcome, including pain and fusion rate; only few studies compared dynamic ADI change pre- to post-operatively. MATERIAL AND METHODS: Retrospectively, we reviewed the medical records of 16 patients who underwent posterior spinal fixation in our center from 2018 to 2019. We used dynamic cervical flexion/extension radiographs to assess the pre- to postoperative change at 12 months in ADI of flexion (ADIf), ADI of extension (ADIe), ADI between flexion/extension (ADIΔ), C1/2 fusion rate and functional outcomes measured by the modified Japanese Orthopaedic Association scale (mJOA scale). Postoperative CT at 3∼12 months assessed screw positioning on the Gertzbein and Robbins classification. RESULTS: In the 16 patients included in this study, ADIf, ADIe and ADIΔ were significantly reduced, from respectively 8.0mm, 5.0mm and 3.0mm preoperatively to 4.6mm, 3.8mm and 0.8mm at 12 months' follow-up. The fusion rate was 81% and the mJOA score recovery rate was 34.9±14.7%. Although the screw malposition rate was higher than in other studies in C1(10%) and C2(20%), there were no new neurologic deficits or worsening of symptoms at follow-up. CONCLUSIONS: The ADIΔ showed significant reduction, showing that the Harms technique of posterior spinal fixation can effective in maintaining the stability of the atlantoaxial joint and improving functional outcome.

Feasibility and Safety of Goel-Harms Posterior C1-C2 Fusion in the Management of Pediatric Reducible Atlantoaxial Instability.

BACKGROUND: Pediatric atlantoaxial instability (AAI) is not common and could be a serious clinical condition. The Goel-Harms technique is one of the most used techniques in adults and needs more evaluation in pediatric populations. This study reports the feasibility and safety of the Goel-Harms technique in the treatment of pediatric reducible AAI. METHODS: In this retrospective cohort study we reported all pediatric patients who underwent Goel-Harms technique for AAI with a minimum 1-year follow up. Patients were clinically assessed using the Japanese Orthopedic Association (JOA) score and radiologically with plain radiographs, computed tomography scan, and magnetic resonance imaging of the craniocervical region. Postoperatively, patients were followed up according to our clinical and radiographic imaging protocol. The following parameters were recorded: JOA score, construct stability, fusion, and abnormal events. RESULTS: A total of 25 patients have completed a 1-year follow-up and fulfilled our criteria. The mean age was 10.68 ± 4.47 (range, 3-17) years. Fifteen patients were male and 10 were female. The final diagnosis included Down syndrome (DS) in 8, type II dens fracture in 7, os odontoideum in 3, and atlantoaxial rotatory fixation in 7. The mean follow-up was 21.76 ± 8.22 months. The preoperative JOA score improved from 15.96 ± 1.46 to 16.76 ± 1.92 at the last follow-up. Sound bone fusion was reported in 92% of patients. CONCLUSIONS: Our data suggest that the Goel-Harms technique is a safe, feasible, and effective procedure in managing pediatric reducible AAI. Special perioperative care should be offered to young AAI patients with DS.

Postoperative complications of Goel-Harms C1-C2 screw-rod fixation technique for C1-C2 instability after C2 nerve sacrifice, a prospective study over two years follow up.

BACKGROUND: Atlantoaxial instability is mainly caused by trauma. C2 nerve is usually needed to be sacrificed for adequate exposure of the lateral mass and screw insertion. OBJECTIVES: This study aimed to investigate the clinical outcome of postoperative complications of C1 and C2 screw-rod fixation using the Goel-Harms technique for C1-C2 instability after sacrificing the C2 nerve root. METHODS: Amongst forty patients with C1-C2 pathology, twenty-seven cases were enrolled into the study, then variables, including age, sex, primary pathology, operation duration, postoperative pain, paresthesia, anesthesia, and other specific conditions, were documented. Data analyzed by an expert biostatistician. p-value < 0.05 was considered significant. RESULTS: Regardless of gender, the most postoperative adverse effect was occipital anesthesia (81.5%). Most of the patients (63%) had both occipital pain and anesthesia one-month post-surgery. At 3- and 6-months post-surgery, occipital pain and anesthesia were seen in 40.7% and 14.8%, respectively. CONCLUSION: The most common postoperative adverse effect of C2 nerve root scarification after C1-C2 fixation is occipital anesthesia followed by occipital paresthesia and pain, which are reduced in severity over time.

Post-traumatic os odontoideum - case presentation and literature review.

Os odontoideum is a rare condition. Nevertheless this condition was described by Giacomini in 1886. It is defined radiologicaly as an oval or round-shaped ossicle of variable size with smooth circumferential cortical margins representing the odontoid process that has no continuity with the body of C2. It is important to review this topic since the upper cervical spinal region is complex from anatomical point of view and has many vital structures passing in close relation to each other. If a person suffers from hyper mobile dens due to insufficiency of its ligamentous complex, it may cause translation of the atlas on the axis and may compress the cervical cord or vertebral arteries. There are cases where patients suffering from Os odontoideum became quadriplegic after a minor trauma. This lesion usually present in pediatric population and its cause is widely debatable today. In our paper we present a review of Os odontoideum in general and present a specific case of a young woman that was diagnosed with Os odontoideum together with the methods that were used to examine, stabilize and finally treat her.

Traumatic Posterolateral C1-C2 Dislocation Complicated with Locked Lateral Mass and Type II Odontoid Fracture-5-Year Follow-up.

OBJECTIVE: We sought to document our experience in managing a rare complex of traumatic posterolateral atlantoaxial dislocation combined with locked lateral mass and type II odontoid fracture. METHOD: A 30-year-old male patient was referred to the author's department. He complained of a decrease in neck range of motion following a traffic accident. Neurologic examination was normal. Computed tomography and open-mouth radiographs showed a type II odontoid fracture and a posterolateral dislocation with a laterally locked left lateral mass at the C1-C2 level. Considering the difficulty and risk in reduction, due to this rare instability and dislocation, a 2-staged treatment was performed. With up to 11 kg skull traction for 7 days before surgery, the locked lateral mass and the lateral dislocation was finally reduced without any neurologic deficit. And once closed reduction was confirmed by open-mouth and lateral X-ray views in the cervical spine, a second staged C1-C2 surgical fixation and fusion with iliac bone graft was performed to achieve a normal anatomic alignment with a better stability. RESULT: The patient showed significant amelioration of neck symptoms postoperatively, and a successful reduction and fixation of the C1-C2 articulation was achieved. At the 5-year follow-up, solid bone fusion was evident on the computed tomography scan. CONCLUSION: For traumatic posterolateral atlantoaxial dislocation complicated with type II odontoid fracture, a closed reduction of the lateral dislocation before operation is both useful and safe because surgeons do not need to reduce the extremely rare lateral dislocation during the operation. Posterior atlantoaxial stabilization and fusion, rather than the occipitocervical fusion as reported previously, is biomechanically stable enough to achieve solid fusion in this rare trauma while not sacrificing the occipitoatlantal joint.

Advantages of an on-the-screwhead crosslink connector for atlantoaxial fixation using the Goel/Harms technique.

The goal of fixation surgery for atlantoaxial instability is to achieve solid bony fusion. Achieving bony fusion as early as possible is beneficial for patients. Although placement of a transverse cross-link connector (XL) provides greater biomechanical strength, XLs have not been able to be placed when performing the Goel/Harms procedure. Recently, placing a XL on the screw head (on-the-head XL [OH-XL]) has become a viable option during the Goel/Harms procedure. However, there is little evidence demonstrating whether applying an OH-XL achieves early solid bony union. A matched-control study was conducted to investigate whether placing an OH-XLs in C1/2 fixation surgery provides earlier bone union or not. Eighteen patients who underwent atlantoaxial fusion with OH-XLs (X-group), and 17 age and sex-matched patients without OH-XLs (NX-group) were compared. Bony union was assessed using reconstructed sagittal and coronal computed tomography images. Six months after surgery, six patients in the X-group and one patient in the NX-group achieved bony union (p = .0338). One year after surgery, 14 patients in the X-group and 4 patients in the NX-group achieved bone union (p = .0010). Two years after surgery, 17 patients in the X-group and 9 patients in the NX-group achieved bony union (p = .0011). This is the first report of the clinical application of OH-XLs for the Goel/Harms procedure. OH-XLs yield earlier bony fusion; thus, placing OH-XLs is beneficial for atlantoaxial fixation surgery using lateral mass screws of the atlas.

Trends in the surgical management of odontoid fractures in patients above 75 years of age: Retrospective study of 70 cases.

BACKGROUND: Odontoid fractures are the most common upper cervical spine fracture in adults over 70 years of age. Hence, treatment of these fractures has public health implications. OBJECTIVES: Evaluate the early complications, bone healing and mortality in patients above 75 years of age who undergo surgical treatment of an odontoid fracture. Compare the results between patients operated with the Harms technique or anterior screw fixation. METHODS: This was a retrospective study of 70 patients with an odontoid fracture who were treated surgically between 2000 and 2015 at the Hôpital de la Timone in France. The age at the time of diagnosis, comorbidities, ASA score and autonomy were evaluated. Bone healing was determined using computed tomography. RESULTS: In the cohort, 22 patients underwent anterior screw fixation, 38 were treated using the Harms technique and 10 with other procedures. The average age was 85.1 years. Fifty-four percent of patients had an ASA score above 3. The average follow-up was 23.4 months. An Anderson type II fracture was present in 80.6% of patients. In the anterior screw fixation group, the operative time was significantly shorter than in the Harms group and no blood transfusions were needed. However, 13.6% of these patients had to be re-operated because the initial construct was unstable; no patients in the Harms group underwent revision surgery. There were more complications in the anterior screw fixation group than in the Harms group: 41% versus 13.2% (P<0.02). The fractures had healed in all patients reviewed after 1 year. The 3-month survival in the anterior screw fixation group was 64.7% and it was 81.3% in the Harms group. These rates were stable at 1 year with no statistical differences between groups. CONCLUSION: Surgical treatment of odontoid fractures in the elderly results in an excellent union rate. The mortality rate is stable after 3 months. In our experience, the Harms technique has a lower risk of complications and better mechanical stability than anterior screw fixation. Despite the steep learning curve, we believe the Harms technique is probably the best choice for treating odontoid fractures in the elderly. LEVEL OF EVIDENCE: IV.

Temporary Internal Fixation Using C1 Lateral Mass Screw and C2 Pedicle Screw (Goel-Harms Technique) without Bone Grafting for Chronic Atlantoaxial Rotatory Fixation.

BACKGROUND: The primary treatment strategy for chronic atlantoaxial rotatory fixation (chro-AARF) is traction followed by bracing or application of a halo device. However, to complete these conservative therapies, patient cooperation is mandatory. If conservative therapy fails, surgery is required for reduction and prevention of recurrence. It has been considered that surgery for atlantoaxial rotatory fixation necessitates solid bony fusion. However, once bony fusion is achieved, loss of range of motion is problematic. Here, we report a patient with chro-AARF who was successfully treated with temporary internal fixation using a C1 lateral mass screw and C2 pedicle screw (Goel-Harms technique) without any grafting of bone or use of bone substitute materials. CASE DESCRIPTION: A 9-year-old boy with chro-AARF was referred to our institution. He had a history of pervasive developmental disorders. He did not cooperate for the completion of conservative therapy and could not tolerate this therapy. Therefore, the orthopedic staff and his parents considered surgery. Under general anesthesia, reduction was easily performed. The Goel-Harms screw-rod construct was completed as a temporary internal fixator without any grafting of bone or use of bone substitute materials. After 6 months, the screw-rod construct was removed. Removal of the screw-rod construct was performed easily without complication. There was no ankylosis of the C1-2 joint, and cervical range of motion was maintained 2.8 years after removal of the construct. CONCLUSIONS: When conservative therapy cannot be continued, Goel-Harms surgery as a temporary internal fixator without bone grafting might be a suitable alternative for selected patients with chro-AARF.

Application of the Harms Technique to Treat Undiagnosed Intractable C1-C2 Unilateral Neck Pain: A Case Report.

A 79-year-old female presented with incapacitating chronic neck pain. The patient's pain which was greatest on the left side persisted for 18 months and was described as stabbing in nature (10/10 intensity). In addition to her neck pain, the patient described having frequent headaches. After six weeks of physical therapy and undergoing a rhizotomy procedure, she showed no prolonged improvement. An epidural steroid injection provided only temporary pain relief and was followed by a successful posterior fusion using the Harms technique with iliac crest autogenous bone grafting and placement of polyaxial screws in the C1 lateral masses and C2 pedicles. At the one-year follow-up the patient reported no pain or complaints. In general, C1-C2 arthrodesis is a surgical challenge due to the proximity of neurovascular structures (vertebral arteries and spinal cord) and wide range of the joint motion. The Harms technique is one of many techniques developed to reduce anatomical risk and improve results related to biomechanical stability and fusion rates.

Comparison between C1-2 Fixation with and without Supplemental Posterior Wiring.

Study Design Retrospective analysis. Clinical Question Is there a difference between the screw-rod construct (SRC) procedure without wiring and the SRC procedure with wiring with respect to fusion, implant failure, reoperation, donor-site morbidity, and complication rates? Patients and Methods We performed a retrospective analysis of 26 patients who underwent C1-2 fixation between 2004 and 2012 (SRC with wiring and structural bone graft, 13 patients; SRC with autograft but without wiring, 13 patients). Fusion was assessed using dynamic X-rays in all patients and computed tomographic scans in selected cases. Pseudoarthrosis was confirmed during reoperation. Results The mean follow-up time was 2 years and 5 months for the SRC without wiring group and 2 years and 1 month for the SRC with wiring group. Patients with less than 1-year follow-up time were excluded. The fusion rate, implant failure rate, and reoperation rates for the SRC without wiring group were 92, 8, and 8%, respectively. The fusion, implant failure, and reoperation rates for the SRC with wiring group were 100, 0, and 0%, respectively. There were no donor-site morbidities or complications in either group (both 0%). There were no differences in parameters we examined between the two groups (p > 0.05 for each rate, Fisher exact test). Conclusions The results suggest that supplementing the SRC procedure with wiring may increase fusion rate, but this difference is not statistically significant. Although the sample size was small, there was not a significant discrepancy in outcomes between the two groups at an average follow-up of 2 years. [Table: see text].

Rod migration into the posterior fossa after harms operation : case report and review of literatures.

C1 lateral mass and C2 pedicle (C1LM-C2P) fixation is a relatively new technique for atlantoaxial stabilization. Complications from C1LM-C2P fixation have been rarely reported. The authors report unilateral rod migration into the posterior fossa as a rare complication after this posterior C1-C2 stabilization technique. A 23-year-old man suffered severe head trauma and cervical spine injury after vehicle accident. He was unconscious for 2 months and regained consciousness. He underwent C1LM-C2P fixation for stabilization of type II odontoid process fracture described by Harms. The patient recovered without a major complication. Twenty months after operation, brain computed tomogram performed at psychology department for disability evaluation showed rod migration into the right cerebellar hemisphere. The patient had mild occipital headache and dizziness only regarding the misplaced rod. He refused further operation for rod removal. To our knowledge, this complication is the first report regarding rod migration after Harms method. We should be kept in mind the possibility of rod migration, and C1LM-C2P fixation should be performed with meticulous technique and long-term follow-up.