Adam C Crowl | PubMed Health

PubMed2005

An anatomical study comparing standard fluoroscopy and virtual fluoroscopy for the placement of C1-2 transarticular screws.

OBJECT: The authors sought to compare radiation exposure, surgical time, and accuracy of screw placement when using either standard fluoroscopy or virtual fluoroscopy for the placement of C1-2 transarticular screws. METHODS: Twenty-two C1-2 transarticular screws were placed in 11 cadavers in a randomized and alternating order by using either standard fluoroscopy or virtual fluoroscopy (fluoronavigation). The radiation time, procedure time, and accuracy of screw placement were recorded and statistically compared. A small but statistically significant reduction in fluoroscopy time was noted with the virtual fluoroscopy technique but the surgical times were similar between the two techniques. The incidence of noncritical and critical breaches (those at risk of causing a neurovascular injury) was not significantly different between the two groups. Careful analysis of the C1-2 anatomy in these specimens underscored the importance of placing the screw path in a maximally dorsal and medial portion of the C-2 isthmus to avoid injury to the vertebral artery and to maximize the bone purchase of the C-1 lateral mass. CONCLUSIONS: Although virtual fluoroscopy may represent a useful tool for transarticular screw placement, it does not supplant traditional surgical techniques and does not appear to lower the incidence of bone breaches that can occur when performing this demanding procedure.

Bone Screws↗

PubMed2005

A cadaveric study comparing standard fluoroscopy with fluoroscopy-based computer navigation for screw fixation of the odontoid.

Although direct osteosynthesis of certain types of odontoid fractures may increase union and decrease the need for prolonged immobilization, screw fixation remains a technically demanding procedure. This study compares radiation exposure, surgical time, and accuracy of hardware placement using standard fluoroscopy versus computer-assisted fluoroscopy-based navigation ("virtual fluoroscopy") to assist with the placement of odontoid screws. Twenty-two cadavers were divided into two groups and underwent placement of a single odontoid screw using either standard fluoroscopic or virtual fluoroscopic guidance. Following screw placement, dissection of the C1-C2 segments was performed to assess accuracy. A significant reduction in fluoroscopy time was noted with the computer-based fluoroscopy technique, whereas the surgical time was not found to differ significantly between the techniques. No critical breaches (those risking neurovascular injury) were noted in either group, and the rate of noncritical breaches did not differ. The authors conclude that fluoroscopy-based virtual navigation appears to have a safety profile similar to standard fluoroscopy while allowing a reduction in radiation exposure.

Bone Screws↗

PubMed2002

Closed reduction and percutaneous fixation of anterior column acetabular fractures.

OBJECTIVE: The current standard treatment of anterior column acetabular fractures includes formal open reduction with internal fixation (ORIF) through a variety of anterior approaches. These approaches have been associated with significant blood loss, infection, lengthy operative times, and neurovascular complications. It therefore seems reasonable to consider less invasive alternatives to conventional treatment methods. A technique for percutaneous reduction and fixation of a particular acetabular fracture pattern is presented. Execution of this technique has been facilitated by the use of image-guided surgical navigation. MATERIALS AND METHODS: A retrospective review was performed on 23 patients who had suffered an acute anterior column fracture of the acetabulum (OTA 62-A3.2, 62-A3.3, 62-B3.2, 62-B3.3) managed with closed reduction and internal fixation using large-bore cannulated screws over an 11-year period. An additional three patients treated during the study period underwent formal ORIF with plates and screws after failure of attempted closed reduction, and were not included in this analysis. Eight of the 23 patients had an associated posterior hemitransverse fracture that was also managed with minimally invasive fixation. A variety of surgical navigation techniques were used to allow accurate percutaneous screw placement: CT-guided percutaneous fixation was performed in 10 patients (1990-1995); fluoroscopy alone was used in four patients (1995-1998); and computer-assisted virtual fluoroscopy was used in nine patients (1999-2002). Some fractures were nondisplaced but potentially unstable, and involved the superior weight-bearing dome; others required closed manipulation using Schanz-pin joysticks placed into the iliac wings and held in place with a temporary external fixator. One patient required a limited open reduction followed by percutaneous screw fixation. After confirmation of adequate reduction, one to three large-bore cannulated screws were placed percutaneously using previously defined safe trajectories. All patients were managed postoperatively with early mobilization and physical therapy. RESULTS: The average preoperative and postoperative displacements were 8.9 and 2.4 mm, respectively. No patient had a loss of reduction during healing. As experience was gained with the computer-assisted imaging, total fluoroscopy times were as little as 6 s, and were routinely kept below 45 s. None of the patients experienced infection, significant blood loss, or iatrogenic neurologic or visceral injury. No symptomatic heterotopic ossification was noted. Of those patients available for follow-up at a minimum of 2 years, the average HSS self-administered hip score was 91. CONCLUSION: We believe that our findings substantiate percutaneous reduction and internal fixation of anterior column acetabular fractures as a safe and effective alternative to formal ORIF, with a low anticipated complication rate and excellent outcome.

Acetabulum↗