Comparative analysis of isocentric 3-dimensional C-arm fluoroscopy and biplanar fluoroscopy for anterior screw fixation in odontoid fractures. ACTA ACUST UNITED AC. 2013;26:189-193. [PMID: 22158300 DOI: 10.1097/bsd.0b013e31823f62c7]

Does the Surgical Approach Matter in Treating Odontoid Fractures? A Comparison of Mechanical Complication Rates Between Anterior Versus Posterior Surgical Approaches: A Meta-Analysis and Systematic Review

Objective

Odontoid fractures are treated surgically through the anterior or posterior approach. Each surgical approach has its advantages and disadvantages, so the preferred approach remains debatable. There are few meta-analyses or systemic reviews on the mechanical complications of surgical treatment for odontoid fractures. This meta-analysis aimed to compare the operation-related morbidity, including mechanical complications, and mortality of patients with odontoid fractures, treated via the anterior or posterior approach.

Methods

A systematic search was performed on PubMed/Medline, Embase, and the Cochrane Library for the studies up to October 2023 on the complication rate of the surgical treatment of odontoid fractures, related to the surgical approach. The risk ratios (RR) with the 95% confidence intervals (CIs) were pooled to assess the mechanical complication rates, other complications, revision surgery, and mortality, depending on the surgical approach.

Results

A total of 1,519 studies were retrieved using the search strategy, and 782 patients from 15 articles were included in this meta-analysis. Mechanical complications were significantly more frequent in the anterior surgical group with low heterogeneity. The incidences of fracture nonunion and revision surgery were also higher in the anterior surgery group. However, there was no significant difference in systemic complications and mortality rates between the two groups.

Conclusion

The posterior approach was more advantageous than the anterior approach in terms of mechanical complications, fusion rates, and incidence of revision surgery. However, further studies, should be performed to strengthen these results.

Does the intraoperative 3D-flat panel control of the planned implant position lead to an optimization and increased in safety in the anatomically demanding region C1/2?

BACKGROUND

The aim of this study was to evaluate the applicability and advantages of intraoperative imaging using a 3D flat panel in the treatment of C1/2 instabilities.

MATERIALS

Prospective single-centered study including surgeries at the upper cervical spine between 06/2016 and 12/2018. Intraoperatively thin K-wires were placed under 2D fluoroscopic control. Then an intraoperative 3D-scan was carried out. The image quality was assessed based on a numeric analogue scale (NAS) from 0 to 10 (0 = worst quality, 10 = perfect quality) and the time for the 3D-scan was measured. Additionally, the wire positions were evaluated regarding malpositions.

RESULTS

A total of 58 patients were included (33f, 25 m, average age 75.2 years, r.:18-95) with pathologies of C2: 45 type II fractures according to Anderson/D'Alonzo with or without arthrosis of C1/2, 2 Unhappy triad of C1/2 (Odontoid fracture Type II, anterior or posterior C1 arch-fracture, Arthrosis C1/2) 4 pathological fractures, 3 pseudarthroses, 3 instabilities of C1/2 because of rheumatoid arthritis, 1 C2 arch fracture). 36 patients were treated from anterior [29 AOTAF (combined anterior odontoid and transarticular C1/2 screw fixation), 6 lag screws, 1 cement augmented lag screw] and 22 patients from posterior (regarding to Goel/Harms). The median image quality was 8.2 (r.: 6-10). In 41 patients (70.7%) the image quality was 8 or higher and in none of the patients below 6. All of those 17 patients the image quality below 8 (NAS 7 = 16; 27.6%, NAS 6 = 1, 1.7%), had dental implants. A total of 148 wires were analyzed. 133 (89.9%) showed a correct positioning. In the other 15 (10.1%) cases a repositioning had to be done (n = 8; 5.4%) or it had to be drawn back (n = 7; 4.7%). A repositioning was possible in all cases. The implementation of an intraoperative 3D-Scan took an average of 267 s (r.: 232-310 s). No technical problems occurred.

CONCLUSION

Intraoperative 3D imaging in the upper cervical spine is fast and easy to perform with sufficient image quality in all patients. Potential malposition of the primary screw canal can be detected by initial wire positioning before the Scan. The intraoperative correction was possible in all patients. Trial registration German Trials Register (Registered 10 August 2021, DRKS00026644-Trial registration: German Trials Register (Registered 10 August 2021, DRKS00026644- https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00026644 ).

Multi-holed biplane drill guide-assisted percutaneous anterior odontoid screw fixation

BACKGROUND

The use of percutaneous anterior screw fixation for odontoid fractures has been widely reported. Because the anatomical characteristics of the odontoid and the screw occupy three-dimensional space, it is challenging to establish the screw trajectory quickly and correctly during the operation.

OBJECTIVE

The purpose of this study was to introduce a multi-holed biplane drill guide that can be used to optimize the guide needle trajectory in percutaneous anterior odontoid screw fixation.

METHODS

Twenty-one patients with type II or rostral type III odontoid fractures were treated with percutaneous anterior single screw fixation. Of these, 12 patients had an unsatisfactory initial guide needle position. A drill guide was used to provide a variety of guide needle tracks.

RESULT

All 12 patients successfully underwent guided screw placement without vascular or neurological complications. Postoperative X-ray and/or CT scans showed that the internal fixation position was satisfactory. At the end of the follow-up period, all patients exhibited bony union without loosening or fractures of the internal fixation.

CONCLUSION

With the imperfect initial position of the guide needle as a reference, the multi-holed biplane drill guide can provide a variety of needle trajectory options in the sagittal and coronal planes for percutaneous anterior odontoid screw fixation. The operator can quickly obtain the ideal guide needle trajectory.

A Technique for the In Vivo Study of Three-dimensional Cervical Segmental Motion Characteristics After Anterior Screw Fixation for Odontoid Process Fractures

STUDY DESIGN

Kinematics of the cervical spine was investigated using cone beam computed tomography (CBCT) images combined with three dimensions to three dimensions (3D-3D) registration technology in patients after anterior odontoid screw fixation (AOSF) surgery.

OBJECTIVE

The aim of this study was to investigate in vivo 3D cervical motion characteristics of patients who had undergone AOSF surgeries.

SUMMARY OF BACKGROUND DATA

AOSF surgery is a classic surgical method for the treatment of odontoid fracture, but there are few studies that investigated its effect on in vivo biomechanics of the cervical spine. Postoperative biomechanical characters of the atlantoaxial joint (C1-C2) and the caudal adjacent segment (C2-C3) have yet to be clarified.

METHODS

The study involved 14 patients subjected to a procedure of AOSF with lag screw. Subjects were matched with 14 healthy controls. All subjects underwent CBCT scanning of the cervical spine under seven functional positions. A 3D-3D registration was performed for each vertebra at each functional position to calculate the segmental motion characteristics. The ranges of motion (ROMs) of the C1-C2, C2-C3, and the overall cervical spine (C1-C7) for each of the functional positions were determined.

RESULTS

The ROMs of the AOSF group were significantly (P < 0.05) smaller than the control group in flexion-extension positions for the C1-C2 (7.0°vs.11.0°), C2-C3 (3.7°vs.6.7°) and C1-C7 (43.3°vs.54.4°). The twisting ROM of the C1-C2 was 39.3° in the AOSF group and 65.7° in the control (P < 0.05), the bending ROM of the C2-C3 was 2.8° in the AOSF group and 8.9° in the control (P < 0.05). The twisting ROM of C1-C7 segment was 63.2° for the AOSF and 98.1° for the healthy control groups (P < 0.05).

CONCLUSION

Although AOSF surgery reduced the flexion-extension ROMs of all investigated spinal segments, additionally, it reduced twisting ROMs of C1-C2 and C1-C7, but only lateral bending ROM of C2-C3, when compared with the control group. The data implied that the AOSF surgery would result in different biomechanics changes in the atlantoaxial segment and caudal adjacent segment. Longer-term follow-up studies of larger patient cohorts are necessary to evaluate the clinical outcomes of patients after the AOSF surgery.Level of Evidence: 3.

Navigated Placement of Two Odontoid Screws Using the O-Arm Navigation System: A Technical Case Report

Odontoid fractures are common cervical spine fractures and lead to atlantoaxial instability depending on their type. Fractures through the base of the odontoid neck are considered for surgery. While the management of these fractures is controversial and may include external immobilization or posterior fusion, an odontoid screw offers the advantages of directly crossing the fracture site while preserving motion at C1-2. Although intraoperative navigation is routinely utilized in spine surgery, there are few reports of navigated anterior odontoid screw placement. In this report, we describe the safe and accurate placement of two anterior odontoid screws using the O-arm navigation system in an octogenarian with a type II odontoid fracture. Details of the technical approach are also provided. The follow-up imaging at three months confirmed the healing of the fracture. Intraoperative navigation using the O-arm system allows for safe and accurate placement of two odontoid screws.

Odontoid Fusion

Anterior odontoid screw fixation allows for the internal fixation of unstable odontoid fractures with low morbidity, good fusion rates, and preservation of the atlanto-axial range of motion when applied in appropriate clinical cases. Advances in surgical techniques have allowed for safer, more minimally invasive approaches that reduce the risk of injury to vital prevertebral structures and minimize soft tissue retraction. Moreover, improvements in surgical image guidance technology for spinal surgery that have been applied to odontoid screw placement have helped improve surgeon confidence about exact screw trajectories. In this chapter, we review traditional screw placement techniques and highlight the trends in technical improvements that improve the safety and efficacy of these procedures.

Radiation exposure and reduction in the operating room: Perspectives and future directions in spine surgery

Intraoperative imaging is vital for accurate placement of instrumentation in spine surgery. However, the use of biplanar fluoroscopy and other intraoperative imaging modalities is associated with the risk of significant radiation exposure in the patient, surgeon, and surgical staff. Radiation exposure in the form of ionizing radiation can lead to cellular damage via the induction of DNA lesions and the production of reactive oxygen species. These effects often result in cell death or genomic instability, leading to various radiation-associated pathologies including an increased risk of malignancy. In attempts to reduce radiation-associated health risks, radiation safety has become an important topic in the medical field. All practitioners, regardless of practice setting, can practice radiation safety techniques including shielding and distance to reduce radiation exposure. Additionally, optimization of fluoroscopic settings and techniques can be used as an effective method of radiation dose reduction. New imaging modalities and spinal navigation systems have also been developed in an effort to replace conventional fluoroscopy and reduce radiation doses. These modalities include Isocentric Three-Dimensional C-Arms, O-Arms, and intraoperative magnetic resonance imaging. While this influx of new technology has advanced radiation safety within the field of spine surgery, more work is still required to overcome specific limitations involving increased costs and inadequate training.

Navigated odontoid screw placement using the O-arm: technical note and case series

OBJECTIVE As odontoid process fractures become increasingly common in the aging population, a technical understanding of treatment approaches is critical. 3D image guidance can improve the safety of posterior cervical hardware placement, but few studies have explored its utility in anterior approaches. The authors present in a stepwise fashion the technique of odontoid screw placement using the Medtronic O-arm navigation system and describe their initial institutional experience with this surgical approach. METHODS The authors retrospectively reviewed all cases of anterior odontoid screw fixation for Type II fractures at an academic medical center between 2006 and 2015. Patients were identified from a prospectively collected institutional database of patients who had suffered spine trauma. A standardized protocol for navigated odontoid screw placement was generated from the collective experience at the authors' institution. Secondarily, the authors compared collected variables, including presenting symptoms, injury mechanism, surgical complications, blood loss, operative time, radiographically demonstrated nonunion rate, and clinical outcome at most recent follow-up, between navigated and nonnavigated cases. RESULTS Ten patients (three female; mean age 61) underwent odontoid screw placement. Most patients presented with neck pain without a neurological deficit after a fall. O-arm navigation was used in 8 patients. An acute neck hematoma and screw retraction, each requiring surgery, occurred in 2 patients in whom navigation was used. Partial vocal cord paralysis occurred after surgery in one patient in whom no navigation was used. There was no difference in blood loss or operative time with or without navigation. One patient from each group had radiographic nonunion. No patient reported a worsening of symptoms at follow-up (mean duration 9 months). CONCLUSIONS The authors provide a detailed step-by-step guide to the navigated placement of an odontoid screw. Their surgical experience suggests that O-arm-assisted odontoid screw fixation is a viable approach. Future studies will be needed to rigorously compare the accuracy and efficiency of navigated versus nonnavigated odontoid screw placement.

Advantages of Direct Insertion of a Straight Probe Without a Guide Tube During Anterior Odontoid Screw Fixation of Odontoid Fractures

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

The aim of this study was to compare the anterior odontoid screw fixation (AOSF) with a guide tube or with a straight probe.

SUMMARY OF BACKGROUND DATA

AOSF associates with several complications, including malpositioning, fixation loss, and screw breakage. Screw pull-out from the C2 body is the most common complication.

METHODS

All consecutive patients with type II or rostral shallow type III odontoid fractures who underwent AOSFs during the study period were enrolled retrospectively. The guide-tube AOSF method followed the standard published method except C3 body and C2-3 disc annulus rimming was omitted to prevent disc injury; instead, the guide tube was anchored at the anterior inferior C2 vertebra corner. After 2 screw pull-outs, the guide-tube cohort was analyzed to identify the cause of instrument failure. Thereafter, the straight-probe method was developed. A guide tube was not used. A small pilot hole was made on the most anterior side of the inferior endplate, followed by insertion of a 2.5 mm straight probe through the C2 body. Non-union and instrument failure rates and screw-direction angles of the guide-tube and straight-probe groups were recorded.

RESULTS

The guide-tube group (n = 13) had 2 screw pull-outs and 1 non-union. The straight-probe group (n = 8) had no complications and significantly larger screw-direction angles than the guide-tube group (60.5 ± 4.63 vs. 54.8 ± 3.82 degrees; P = 0.047).

CONCLUSION

Straight-probe AOSF yielded larger direction angles without injuring bone and disc. Complications were absent. The procedure was easier than guide-tube AOSF and assured sufficient engagement, even in horizontal fracture orientation cases.

LEVEL OF EVIDENCE

3.

Isocentric C-arm three-dimensional navigation versus conventional C-arm assisted C1-C2 transarticular screw fixation for atlantoaxial instability

OBJECTIVE

The Isocentric C-arm 3D navigation has been widely used in superior cervical surgeries in recent years. Several clinical researches reported that navigation system was an effective support device for treatment of atlantoaxial instability. But there were few studies about the advantages of navigation system compared to conventional C-arm fluoroscopy in C1-C2 transarticular screw fixation for atlantoaxial instability. The aim of the study was to evaluate the precision of computer-assisted C1-C2 transarticular screw fixation (Magerl's technique) for atlantoaxial instability and compare the clinical results with conventional C-arm fluoroscopy.

METHODS

Forty-two patients diagnosed as atlantoaxial instability who underwent C1-C2 transarticular screw fixation under two different fluoroscopy methods were studied. The Iso-C 3D navigation group included 18 patients and the other 24 patients were in the conventional C-arm group. The clinical and radiographic results were recorded and compared between the two groups. Patients were followed up with clinical examination and radiographs at a mean of 18.4 months.

RESULTS

There were no significant differences between two groups in the mean age, gender, and causes of atlantoaxial instability. The mean blood loss in the navigation group was 236.1 ± 28.5 mL versus 308.3 ± 21.2 mL in the conventional C-arm group. The radiation time was significantly reduced using 3D navigation (48.8 ± 1.05 s versus 60.3 ± 2.23 s). Overall, 97.2 % (35/36) of 3D navigated screws and 91.7 % (44/48) of fluoroscopy screws were placed into the C1-C2 transarticular passages. Thirty-nine of forty patients showed evidence of solid fusion after 12 months on cervical plain radiographies or CT scans.

CONCLUSIONS

On comparing the two imaging techniques, it was found that using Iso-C 3D navigation can improve accuracy of the C1-C2 transarticular screws, decrease intra-operative fluoroscopic time and blood loss, and not prolong the operative time. This study demonstrates that Iso-C 3D navigation is a safe and effective means of guiding C1-C2 transarticular screw fixation for atlantoaxial instability.

Management of C1–2 traumatic fractures using an intraoperative 3D imaging–based navigation system

OBJECT

Fractures of C-1 and C-2 are complex and surgical management may be difficult and challenging due to the anatomical relationship sbetween the vertebrae and neurovascular structures. The aim of this study was to evaluate the role, reliability, and accuracy of cervical fixation using the O-arm intraoperative 3D image–based navigation system.

METHODS

The authors evaluated patients who underwent a navigation system–based surgery for stabilization of a fracture of C-1 and/or C-2 from August 2011 to August 2013. All of the fixation screws were intraoperatively checked and their position was graded.

RESULTS

The patient population comprised 17 patients whose median age was 47.6 years. The surgical procedures were as follows: anterior dens screw fixation in 2 cases, transarticular fixation of C-1 and C-2 in 1 case, fixation using the Harms technique in 12 cases, and occipitocervical fixation in 2 cases. A total of 67 screws were placed. The control intraoperative CT scan revealed 62 screws (92.6%) correctly placed, 4 (5.9%) with a minor cortical violation (< 2 mm), and only 1 screw (1.5%) that was judged to be incorrectly placed and that was immediately corrected. No vascular injury of the vertebral artery was observed either during exposition or during screw placement. No implant failure was observed.

CONCLUSIONS

The use of a navigation system based on an intraoperative CT allows a real-time visualization of the vertebrae, reducing the risks of screw misplacement and consequent complications.

[Anterior odontoid screw fixation using intra-operative cone-beam computed tomography and navigation]

OBJECTIVE

The purpose of this study was to asses the value of intraoperative cone-beam CT (O-arm) and stereotactic navigation for the insertion of anterior odontoid screws.

MATERIALS AND METHODS

this was a retrospective review of patients receiving surgical treatment for traumatic odontoid fractures during a period of 18 months. Procedures were guided with O-arm assistance in all cases. The screw position was verified with an intraoperative CT scan. Intraoperative and clinical parameters were evaluated. Odontoid fracture fusion was assessed on postoperative CT scans obtained at 3 and 6 months' follow-up

RESULTS

Five patients were included in this series; 4 patients (80%) were male. Mean age was 63.6 years (range 35-83 years). All fractures were acute type ii odontoid fractures. The mean operative time was 116minutes (range 60-160minutes). Successful screw placement, judged by intraoperative computed tomography, was attained in all 5 patients (100%). The average preoperative and postoperative times were 8.6 (range 2-22 days) and 4.2 days (range 3-7 days) respectively. No neurological deterioration occurred after surgery. The rate of bone fusion was 80% (4/5).

CONCLUSION

Although this initial study evaluated a small number of patients, anterior odontoid screw fixation utilizing the O-arm appears to be safe and accurate. This system allows immediate CT imaging in the operating room to verify screw position.

Pooled analysis of non-union, re-operation, infection, and approach related complications after anterior odontoid screw fixation

Background

Anterior odontoid screw fixation (AOSF) has been one of the most popular treatments for odontoid fractures. However, the true efficacy of AOSF remains unclear. In this study, we aimed to provide the pooled rates of non-union, reoperation, infection, and approach related complications after AOSF for odontoid fractures.

Methods

We searched studies that discussed complications after AOSF for type II or type III odontoid fractures. A proportion meta-analysis was done and potential sources of heterogeneity were explored by meta-regression analysis.

Results

Of 972 references initially identified, 63 were eligible for inclusion. 54 studies provided data regarding non-union. The pooled non-union rate was 10% (95% CI: 7%–3%). 48 citations provided re-operation information with a pooled proportion of 5% (95% CI: 3%–7%). Infection was described in 20 studies with an overall rate of 0.2% (95% CI: 0%–1.2%). The main approach related complication is postoperative dysphagia with a pooled rate of 10% (95% CI: 4%–17%). Proportions for the other approach related complications such as postoperative hoarseness (1.2%, 95% CI: 0%–3.7%), esophageal/retropharyngeal injury (0%, 95% CI: 0%–1.1%), wound hematomas (0.2%, 95% CI: 0%–1.8%), and spinal cord injury (0%, 95% CI: 0%–0.2%) were very low. Significant heterogeneities were detected when we combined the rates of non-union, re-operation, and dysphagia. Multivariate meta-regression analysis showed that old age was significantly predictive of non-union. Subgroup comparisons showed significant higher non-union rates in age ≥70 than that in age ≤40 and in age 40 to <50. Meta-regression analysis did not reveal any examined variables influencing the re-operation rate. Meta-regression analysis showed age had a significant effect on the dysphagia rate.

Conclusions/Significances

This study summarized the rates of non-union, reoperation, infection, and approach related complications after AOSF for odontoid factures. Elderly patients were more likely to experience non-union and dysphagia.

Multimodality management of vertebral artery injury sustained during cervical or craniocervical surgery

BACKGROUND

Iatrogenic vertebral artery (VA) injury is a rare but potentially devastating complication associated with cervical and craniocervical surgery.

OBJECTIVE

To retrospectively evaluate treatment modalities and outcomes associated with iatrogenic VA injury.

METHODS

Our institutional surgical database was queried for patients who underwent cervical or craniocervical surgery from January 1997 to August 2012.

RESULTS

During this time period, 8213 patients underwent cervical or craniocervical surgery, and 17 (0.2%) cases of VA injury were identified. Eight (47%) of these injuries occurred during C1-2 instrumentation procedures. Primary microsurgical repair of the VA was performed in 5 patients. Other cases were managed by either surgical or endovascular VA occlusion. Of the 17 patients, 15 underwent immediate angiography, 9 of whom were ultimately treated by the use of endovascular techniques.

CONCLUSION

VA injury is an uncommon complication of cervical and/or skull base surgery. Standardized management recommendations may help reduce complications associated with these rare but potentially devastating injuries.

Intraoperative CT in the assessment of posterior wall acetabular fracture stability

Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images.