Biomedical subjects

Cory Collinge

Publications and source records attributed to Cory Collinge.

6 recordsLinked to original sources

PubMed2006

Effects of surgical errors on small fragment screw fixation.

OBJECTIVES: The purpose of this study is to determine the effects of technical errors that occur during the application of small fragment screw fixation and to assess which screw holes can be salvaged. INTERVENTION: Testing of screw pullout from a bone substitute model on a universal testing instrument (Instron Corp., Canton, MA). OUTCOME MEASUREMENTS: Testing was performed on 9 sets of 12 small fragment screws applied to a bone substitute model using the instruments available in a small fragment set (Synthes, Paoli, Pa). In the first 2 sets, 3.5-mm cortical screws and 4.0-mm cancellous screws were placed using the proper instrumentation according to recommended AO/ASIF techniques. The other 7 sets were inserted using "incorrect" methods: a single step was altered intentionally to assess its influence on fixation strength. The third set of screws included 3.5-mm cortical screws placed after drilling the pilot hole with a 3.5-mm drill. For the fourth set, the 2.5-mm drill was used, but the hole was tapped using the 4.0-mm cancellous tap before insertion of a 3.5-mm cortical screw. In set five, 4.0-mm cancellous screws were placed after tapping the hole with a 3.5-mm cortical tap. Set 6 included cancellous screws placed without tapping. The seventh set included 3.5-mm cortical screws that were placed according to recommended methods, and then removed and replaced into the screw hole. Set number 8 included 3.5-mm cortical screws, which were inserted correctly and then stripped by overtightening. The ninth set included 3.5-mm cortical screws that were stripped as those in set 8; the stripped screws were removed, the holes were packed with bone material, and the screws were replaced. All screws were inserted to a thread depth of 32 mm. RESULTS: Drilling a 3.5-mm pilot hole for a 3.5-mm cortical screw and "stripping" the screw by overtightening resulted in 76% and 82% less pullout strength, respectively, than when the proper technique was used (P<0.01). Use of the wrong tap before placement of a 3.5-mm cortical or 4.0-mm cancellous screw decreased pullout strength by 12% and 11%, respectively (P<0.01). Exchanging screws of similar geometry had no significant effect on screw pullout strength (P>0.1). Inserting a 4.0-mm cancellous screw without tapping actually increased pullout strength by 4% (P<0.01). CONCLUSIONS: Alterations from recommended techniques for the placement of orthopedic screws had varying effects on screw fixation, as assessed by the pullout strength. Clinically, these findings indicate that, in some cases, a screw hole that was not initially placed according to the optimal technique may be salvaged. Finally, the authors recommend that careful vigilance be maintained at all times in surgery and that fixation be applied according to sound principles in an effort to avoid some of these problems.

Bone Screws↗

PubMed2005

Risks to the superior gluteal neurovascular bundle during percutaneous iliosacral screw insertion: an anatomical cadaver study.

BACKGROUND: Iliosacral screws are a popular technique used to treat complicated injuries of the pelvis. It is well recognized that this technique entails some potentially disabling complications, including damage to vessels and lumbosacral nerves. The recommended insertion site for iliosacral screws into the S1 body lies along the posterior ilium between the greater sciatic notch and the iliac crest. The anatomy and course of the superior gluteal nerve and vessels have been described along the outer aspect of the posterior ilium. Injury to the superior gluteal nerve and vessels has been reported during pelvic surgery, including the insertion of iliosacral screws. The purpose of this study is to assess the risks of injury and proximity of percutaneously inserted iliosacral screws to the superior gluteal nerve and vessels using a cadaver model. MATERIALS AND METHODS: Twenty-nine cadaver pelvises for a total of 58 sides (58 screws) were studied. Percutaneous iliosacral screws were placed into the first sacral bodies using multiplanar fluoroscopic guidance. The superior gluteal neurovascular bundle was then studied via a posterior dissection. Injury to the neurovascular bundle was noted if it occurred, and the distance between the screw head and the neurovascular bundle was measured. Distances from the screw head to the crista glutea, greater sciatic notch, and iliac crest were also measured. RESULTS: The branching pattern of the superior gluteal nerve and vessels after they exit the greater sciatic notch demonstrated considerable variation, but was generally consistent with prior descriptions in most cases. Ten of 58 (18%) iliosacral screws caused injury to the superior branch of the superior gluteal nerve and vessels; 8 neurovascular bundles were impaled and 2 others were partly entrapped between the screw head and the ilium. The mean distance from the head of the iliosacral screws to the deep superior branches of the superior gluteal nerve and vessels was 9.1 mm (+/- 6.8 mm). The mean distances from the screw head to the crista glutea, sciatic notch, and iliac crest were 19.5 mm (+/- 4.9 mm), 33.0 mm (+/- 6.4 mm) and 50.3 mm (+/- 4.6 mm). Of the screws that caused superior gluteal nerve and vessels injury, all were within the "desired" area of insertion. CONCLUSIONS: The deep superior branch of the superior gluteal nerve and vessels, which provides major blood and nerve supply to the G. medius and G. minimus, is at significant risk during the percutaneous placement of iliosacral screws even when "well placed" and soft tissue protecting cannulas are used. The clinical effects of these injuries remain poorly understood.

Bone Screws↗

PubMed2005

Standard multiplanar fluoroscopy versus a fluoroscopically based navigation system for the percutaneous insertion of iliosacral screws: a cadaver model.

OBJECTIVES: To compare the safety and efficiency of standard multiplanar fluoroscopy (StdFluoro) and virtual fluoroscopy (VirtualFluoro) for use in the percutaneous insertion of iliosacral screws. DESIGN: : Human cadaver study comparing 2 imaging modalities during iliosacral screw insertion; imaging randomized from side to side. SETTING: Bioskills laboratory in a medical school. PARTICIPANTS: Twenty-nine embalmed whole human cadavers without prior hip or pelvic surgery. INTERVENTION: Iliosacral screws were inserted into the S1 bodies using a percutaneous insertion technique. Screws were inserted on one side using StdFluoro, and on the other side, screws were placed using VirtualFluoro. MAIN OUTCOME MEASUREMENTS: Time necessary for imaging preparation, screw insertion, and actual fluoroscopy were recorded. Accuracy and safety of screw placement was assessed using computed tomography and an anatomic dissection of the pelvis. RESULTS: : Fifty-six of 58 iliosacral screws were placed within the desired bony corridor of the posterior pelvis. One screw placed using each method was inserted erroneously, but both were relatively minor deviations. There were no obvious injuries to major vessels or nerve roots. The total surgical time required for preparation of imaging and screw insertion averaged 7.3 minutes using StdFluoro and 6.7 minutes using VirtualFluoro (P = 0.4). Although the time necessary for screw insertion using VirtualFluoro averaged only 3.5 minutes, compared to 7.0 minutes for StdFluoro (P < 0.05), this time savings was offset by that required for application and calibration of tracking devices when using VirtualFluoro. The average fluoroscopy time using StdFluoro method was 26 seconds, whereas that for the VirtualFluoro was only 6 seconds (P < 0.01). CONCLUSIONS: Most of the percutaneous iliosacral screws were safely inserted using StdFluoro and VirtualFluoro, and total surgical times were similar using both methods. As VirtualFluoro continues to evolve, improved efficiency in operative times may be expected. Currently, the most beneficial aspect of using VirtualFluoro during the insertion of percutaneous iliosacral screws appears to be significantly decreased use of fluoroscopy when compared to StdFluoro.

Aged↗

PubMed2004

Soft tissue injuries associated with pelvic fractures.

Significant soft tissue injuries often occur as part of high-energy injuries to the pelvis. These soft tissue injuries must be recognized and considered when implementing a treatment plan if complications are to be minimized. Vigilance in diagnosing open fractures must be maintained. Patients with these injuries must be managed aggressively, because they are at high risk for complications and death. Closed pelvic and acetabular fractures also may include soft tissue injury that requires special consideration. Careful evaluation and management of the soft tissues aids in determining appropriate techniques for reduction and fixation of the associated fractures.

Combined Modality Therapy↗

PubMed2004

Early results of the less invasive stabilization system for mechanically unstable fractures of the distal femur (AO/OTA types A2, A3, C2, and C3).

OBJECTIVES: Historically, mechanically unstable fractures of the distal femur have been difficult to treat. Problems such as varus collapse, malunion, and nonunion frequently resulted before fixed-angle plates and indirect reduction techniques were popularized. More recently, the Less Invasive Stabilization System, or LISS (Synthes, Paoli, PA), has been designed to combine these 2 approaches with the intended goals of achieving adequate stable fixation and early healing. Early clinical results for the femoral Less Invasive Stabilization System have been promising. The purpose of this study is to evaluate the clinical results of patients with high energy, mechanically unstable fractures of the distal femur treated with the Less Invasive Stabilization System. DESIGN: Retrospective analysis of a treatment protocol, consecutive patient series. SETTING: Busy level II trauma center. PATIENTS /PARTICIPANTS: Twenty-six patients with 27 high-energy AO/OTA types A2, A3, C2, and C3 fractures of the distal femur. INTERVENTION: Treatment with indirect fracture reduction and internal distal femoral fixation using the Less Invasive Stabilization System. MAIN OUTCOME MEASUREMENTS: Clinical and radiographic assessment. RESULTS: Twenty-one patients with 22 fractures were available for evaluation at an average 19 months postinjury (range 12-35 months). The mechanism of injury included 12 motor vehicle collisions, 4 high falls, 5 motorcycle crashes, and 1 bicyclist struck by a car. Twenty patients had associated injuries. Six fractures were open. All fractures were comminuted; according to the AO/OTA fracture classification there were 4 A2, 3 A3, 12 C2, and 3 C3 fractures. All fractures healed without secondary surgeries at a mean of 13 weeks (range 7-16 weeks). There were no cases of failed fixation, implant breakage, or infection. Average joint line orientation relative to the femoral shaft axis (valgus) measured 99 degrees on postoperative radiographs and 99 degrees on final radiographs. A comparison of postoperative to healed final radiographs for each femur demonstrated no case with greater than a 3 degrees difference in either varus or valgus. Complications included 1 mal-union where the fracture was fixed in 8 degrees of valgus and 2 cases of external rotation between 10 degrees and 15 degrees. Painful hardware occurred in 4 patients, of which 3 underwent implant removal. The average knee range of motion was 5 degrees to 114 degrees. CONCLUSIONS: The Less Invasive Stabilization System allows for stable fixation and facilitates early healing in mechanically unstable high-energy fractures of the distal femur. There were no patients with fixation failure, varus collapse, or nonunion in this "at-risk" population. This treatment safely allows for immediate postoperative initiation of joint mobility and the progression of weight bearing with early radiographic signs of healing.

Adolescent↗

PubMedDate not supplied

Anterior-inferior plate fixation of middle-third fractures and nonunions of the clavicle.

OBJECTIVE: Results of surgical treatment for clavicle injuries using standard approaches have shown relatively high complication rates including loss of fixation, persistent nonunion, implant related problems, and the need for subsequent surgeries are common. The purpose of this study is to evaluate the clinical results of patients treated for clavicle fractures and painful clavicular nonunions with anterior-inferior plating using a 3.5 mm plate. DESIGN: Consecutive clinical series. SETTING: 3 tertiary care academic trauma centers (Level 1 and 2). PATIENTS: Eighty consecutive patients with a middle-third fracture or painful nonunion of the clavicle. INTERVENTION: Open reduction and internal fixation using an anterior-inferior plating technique with a precontoured 3.5 mm plate and lag screw(s). Nonunions received autologous bone grafts. MAIN OUTCOME MEASUREMENTS: Patients were evaluated using physical and radiographic examination, the American Shoulder and Elbow Surgeons Shoulder Assessment (ASES), and the Short Form-36 (SF-36) outcomes questionnaire. RESULTS: Fifty-eight patients had sufficient records and follow-up of at least 24 months (mean 49 months). Clinical and radiographic union was present at a mean of 9.5 weeks for patients treated for acute fracture and 10.5 weeks those treated for nonunion. Complications included 1 failure of fixation, 1 nonunion, and 3 infections. Two patients underwent implant removal for bothersome hardware. Shoulder motion was good or excellent in all patients except those with neurologic injury. Functional results (ASES and SF-36) were good or excellent for the vast majority of patients, except those with neurologic injury. CONCLUSIONS: Anterior-inferior plating of acute middle-third fractures of the clavicle and clavicular nonunions using a plate and lag screws typically results in early healing, few complications and an excellent return of function. Advantages of this technique include stable bony fixation with instrumentation directed away from potentially dangerous infraclavicular structures and a minimal incidence of implant prominence problems.

Adolescent↗