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At least 199 records · Page 11Linked to original sources
PubMed2001

Dural reconstruction with fascia, titanium mesh, and bone screws: technical note.

OBJECTIVE: After the resection of cranial base tumors, there may not be enough free dural margin left for reconstruction after involved bone and dura have been removed. In such a situation, dural reconstruction becomes a problem. We propose a new technique of dural closure in such cases. METHODS: A fascial graft is prepared from either fascia lata, abdominal fascia, pericranium, or temporal fascia and is trimmed to a size slightly larger than that of the dural defect. The fascial graft is placed over the dural defect and affixed to the underlying bone with a piece of titanium mesh, titanium screws, or both. The graft is then reinforced with fibrin glue. RESULTS: This method of dural reconstruction has been used in five patients with basal meningiomas. Three were in the petromastoid area, and two were in the planum-ethmoid area. None of these patients experienced postoperative cerebrospinal fluid leak, and none experienced any complications related to the reconstruction. CONCLUSION: This technique of dural reconstruction can be used in selected cases of basal tumors without enough free dural margin to sew into a fascial graft.

Biocompatible Materials↗
PubMed1992

[Arthroscopic and percutaneous bone screw techniques with a new screw system].

A new screwdriver is presented with which small titanium screws can be introduced into a joint under arthroscopic guidance. The screws are centrally cannulated, 2.7 mm thick (thread diameter), and available with and without a washer (5 mm in diameter, serrated and convex, flexible but not removable). The screwdriver has a special screw-holding device which allows the screw to be grasped and released making it possible to remove a screw already implanted in the joint at an earlier time. This arthroscopic screwing system has been used in 81 cases to date. In 59 patients with shoulder instability, arthroscopic refixation of the detached labrum-capsule complex was performed. In the first 32 of these cases an intra-articular screwing technique was used and in the following 27 cases an extra-articular screwing technique was applied. In addition, in 9 patients a fractured and displaced greater tuberosity was reduced and fixated percutaneously under the guidance of an image intensifier by means of this screwdriver. Other fields of application were the knee joint (type III fracture of the intercondylar eminence in 5 patients) and the ankle (displaced fracture of the talus in 2 patients and osteochondritis dissecans in 1). Complications were seen only in the patients with shoulder instability who were treated by the intra-articular screwing technique (screw loosening in 4 patients). This was the reason why the intra-articular technique was replaced by the extra-articular method. Since that time no further complications caused by the screws have been seen. Redislocation of the shoulder joint occurred in 1 case 7 months after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthroscopes↗
PubMed1997

Pullout strengths of cannulated and noncannulated cancellous bone screws.

The pullout strengths of large diameter cannulated and noncannulated cancellous screws were tested in a synthetic polyurethane foam. The foam was fabricated to have mechanical properties equivalent to human cancellous bone and was characterized by compression testing before screw pullout. Long and short thread commercially available screws from four manufacturers were tested. In screws with short threads (16-22 mm), there was no difference in holding power among the four cannulated screw designs. However, the short thread noncannulated screw performed significantly better than the short thread cannulated screw with the lowest pullout strength. There were statistically significant differences in holding power among the different long thread (32-40 mm) cannulated screw designs. Additionally, the long thread noncannulated screw had better holding power than several of the long thread cannulated screws. No differences in pullout strengths between comparably sized cannulated and noncannulated screws produced by the same manufacturer were found, and all long thread screws had significantly greater holding power than all short thread screws. There was no demonstrable effect on holding power when screws were inserted with or without tapping. Thread surface area was found to be a reasonable predictor of holding power.

Bone Screws↗
PubMedDate not supplied

The Osteomed M3-X Fixation System: a new bone screw with applications in foot surgery.

The purpose of this article is to familiarize the reader with the Osteomed M3-X Fixation System. The authors present a description of the instrumentation and design characteristics of this system, as well as some comparisons to other similar fixation devices. The indications for the screw's use and the correct techniques of insertion are also discussed. In addition, a review of over 200 forefoot procedures utilizing this system, and performed by the podiatric surgeons at Hutzel Hospital, is presented.

Adolescent↗
PubMed1998

The stability of bone screws in the os sacrum.

A variety of points of insertion and implantation techniques are recommended for inserting screws into the os sacrum. On the basis of 16 complete human sacrum specimens the following axial pull-out tests were performed: 1. Insertion of convergent measuring screws, 6.0 mm and 7.0 mm in outside diameter respectively, into the body of vertebra S1 using a monocortical and bicortical technique respectively with perforation of the ventral cortex. 2. Insertion of divergent screws into the ala sacralis at the level of S1 with 6-mm and 7 mm screws respectively, using a monocortical technique without perforation of the ventral cortex. 3. Insertion of convergent 6-mm screws into the body of vertebra S2 using a monocortical and bicortical technique respectively with perforation of the ventral cortex. The highest axial pull-out force was reached using convergent 6-mm screws inserted into the body of vertebra S1 using the bicortical technique with perforation of the ventral cortex (2392.4 N). The use of a 7.0-mm screw in the same implantation technique did not result in higher pull-out forces (2274.7 N). The monocortical technique reached a pull-out force of 1657.53 N with a 6-mm screw and 1505.64 N with a 7-mm screw. Convergent insertion of 6-mm screws into the body of S2 resulted in pull-out forces of 537.02 N using a bicortical and only 297.71 N using a monocortical technique. Divergent insertion of screws into the ala sacralis reached a maximal pull-out force of 495.47 N using 6-mm screws and 449.79 N using 7-mm screws. These data resulted from a monocortical implantation technique without perforation of the ventral cortex of the ala sacralis. The results of the present biomechanical study show that convergent bicortical implantation in the body of S1 is the most stable technique for screw fixation in the sacrum. The use of 7-mm rather than 6-mm screws did not lead to increased primary stability. Anatomic studies have shown that a safe area exists in the region of the ventral promontory, so this implantation technique appears to be unobjectionable.

Adult↗
PubMed1987

Management of lower limb burns using suspension of the leg by means of ASIF bone screws. An analysis of the results.

Skin grafts on the dorsal side of the legs are liable to failure because of mechanical trauma, maceration and subsequent infection. Suspension of the legs in traction is a well-known method to overcome these problems. In 1984 and 1985, in 14 patients who underwent skin grafting on the dorsum of the leg, suspension was attained by means of two ASIF screws drilled in the ventral side of the proximal and distal tibia. The 'take' percentage of the transplantations on the dorsum of the legs was the same as the 'take' percentage of skin grafts on other sites of the body. No serious complications were encountered.

Bone Screws↗
PubMed1996

Experimental analysis of internal rigid fixation osteosynthesis performed with titanium bone screw and plate systems.

The authors report the results of an experimental analysis performed on titanium miniplates and screws in order to gain a better understanding of dynamic forces in internal rigid fixation. Ten segments of bovine scapula were prepared. Osteotomies were carried out along the minor axis, following which five were fixed with four hole straight miniplates and the other five with six hole double-Y miniplates. Each sample was fastened in a special clamp adapted to a tension test machine and shearing force was applied. Force versus time was recorded and the 50 bone fragments were examined by a pathologist. On the basis of the test results, two simple computer models were developed. No significant difference was evident between the mechanical and computed tests. The most critical sections were located near the hole proximal to the osteotomy and the microscopic findings confirmed this. On the basis of the experimental results, the authors propose a new plate design in which the area subject to most stress, proximal to the bone section, would be of miniplate thickness, the distal aspect being thinner as in a microplate. It is suggested that this design would provide sufficient stability and a high degree of anatomical adjustment of the system.

Animals↗
PubMed1995

Analysis of the torque applied to bone screws by trauma surgeons. Comparisons based on years of experience and material of implant construction.

Stability of an internal fixation construct is dependent on the torque placed on the screws holding the plate, the number of screws in the construct, and the number of cortices purchased by each screw. This study addresses the ability of surgeons to apply uniform torque and the variability between stainless steel and titanium. A total of 630 measurements were made by trained orthopedists using a device to measure the torque applied to 3.5 mm screws when tightening them to a plate. Variations were found to be significant depending on the number of years the orthopedist was in practice and the type of construct material used. The average torque applied to a stainless steel construct is 5.82 in-lb, while the torque applied to titanium is 5.41 in-lb (P < 0.01). The longer an orthopedist is in practice, the more torque will be applied to the screw/plate construct.

Biomechanical Phenomena↗
PubMed2003

The tongue-base suspension using Repose bone screw system in a child with Simpson-Golabi-Behmel syndrome. Case report.

Obstructive sleep apnea syndrome is one of the most frequent manifestations of upper airway obstruction. Several approaches have been proposed to solve this problem with the aim to avoid tracheotomy especially in children. We observed a child affected by Simpson-Golabi-Behmel syndrome presenting severe OSAS. He underwent tongue-base suspension using the Repose system with significant improvement of the polysomnographic parameters and of the clinical conditions. Tongue suspension with this technique effectively prevent tongue-base collapse, avoiding tracheotomy or increased morbidity caused by a more invasive procedure. Besides it does not interfere with the patient's cranio-facial growth and future occlusion.

Bone Screws↗
PubMed2004

Increased insertion torque delays pin-bone interface loosening in external fixation with tapered bone screws.

OBJECTIVE: To test the null hypothesis that osseomechanical integration is not related to the maximum insertion torque of tapered external fixation pins. DESIGN: Prospective in vivo study in a functionally loading ovine model. In 12 animals, tapered commercial external fixation pins were inserted at predefined locations with measured insertion torques and extraction torque measured at 10 weeks postoperatively. SETTING: Unrestricted stall activity under veterinary supervision. INTERVENTIONS: Under general anesthesia and aseptic conditions, mid-diaphyseal tibial osteotomies were created and a 3-mm gap width stabilized with a custom-made, high-precision, single-sided external fixator, in compliance with United Kingdom government regulations [Animals (Scientific Procedures) Act 1986]. MAIN OUTCOME MEASUREMENTS: Primary pin site stability and interface load were assessed by measuring maximum insertion torque (Nm). At a 10-week postoperative end point, osseomechanical stability was assessed by measuring the extraction torque and a pin performance index determined from the insertion/extraction torque ratio. RESULTS: A positive correlation was found between extraction torque and insertion torque (R2 = 0.322, P < 10(-6)). All pins with an insertion torque equal to or greater than 7 Nm had a measurable extraction torque, as did 98% of the pins with an insertion torque above 5 Nm. Extraction torque decreased both as a function of pin site position by the postoperative end point. High insertion torques were found to enhance end point stability in both diaphyseal and metaphyseal bone. CONCLUSION: The data from this study indicate that tapered external fixation pins should be inserted with a high torque to enhance the long-term integrity of the pin-bone interface.

Animals↗
PubMed2000

Pharyngeal suspension suture with repose bone screw for obstructive sleep apnea.

OBJECTIVE: Multilevel surgery for obstructive sleep apnea syndrome (OSA) may improve success. This study's goal is to prospectively evaluate the feasibility and short-term subjective effectiveness of a new tongue-suspension technique. METHODS: A multicenter nonrandomized open enrollment trial used the Repose device to treat tongue obstruction in 39 snoring and OSA patients. Outcomes include 1- and 2-month subjective reports of general health, snoring, and sleep. RESULTS: Twenty-three patients completed 1 month and 19 completed 2 months of follow-up. In OSA patients, activity level, energy/fatigue, and sleepiness improved. Two-month outcomes were less (activity level, energy/fatigue, and sleepiness). Fewer changes were observed in snorers than in OSA patients. There were 6 complications (18%), including sialadenitis (4), gastrointestinal bleeding (1), and dehydration (1) after the procedure. CONCLUSION: A pharyngeal suspension suture changes subjective outcomes. Improvement is incomplete. The procedure is nonexcisional, but significant complications may occur. Further evaluation is required to demonstrate effectiveness.

Adult↗
PubMed2002

Role of the tongue base suspension suture with The Repose System bone screw in the multilevel surgical management of obstructive sleep apnea.

OBJECTIVE: The Repose System (tongue base suspension) is a new, minimally invasive technique for tongue base suspension in the treatment of obstructive sleep apnea. The purpose of this project was to describe our preliminary experience using this tongue base suspension system in conjunction with uvulopalatopharyngoplasty (UPPP) in the multilevel surgical approach to the management of obstructive sleep apnea (OSA). STUDY DESIGN: We conducted a retrospective analysis of 19 consecutive patients undergoing UPPP and The Repose System tongue base suspension for the management of obstructive sleep apnea during a 1-year period (1998 through 1999). RESULTS: Fifteen patients (11 men and 4 women) had complete preoperative and postoperative polysomnographic data. A 46% reduction in the preoperative respiratory disturbance index (RDI) (38.7 +/- 12.3) versus the postoperative RDI (21.0 +/- 7.4, P < 0.05) was demonstrated at a mean of 3.8 months after surgery. The apnea index demonstrated a 39% reduction. The surgical cure rate was 20% (3 of 15 patients). CONCLUSIONS: The Repose System in conjunction with UPPP has been shown to produce significant reductions in the RDI and apnea index as well as a significant increase in O2 saturation. Despite the improvement in these objective parameters, the overall surgical cure rate was only 20% (3 of 15 patients) in this retrospective series. Further research is warranted to define the role of The Repose System in the management of obstructive sleep apnea patients with multilevel airway obstruction.

Bone Screws↗
PubMedDate not supplied

[Increasing bone screw anchoring in the femur head by cement administration via the implant--a biomechanical study].

PURPOSE: Osteoporosis reveals a higher risk of fractures. Due to the lack of possibilities to anchor fixation elements, fracture treatment often turns out to be complicated. An experimental study served to investigate the extent to which the application of bone cement through a modified gliding screw (Dynamic Hip Screw DHS) would improve the screw anchoring in osteoporotic femoral heads. METHODS: Quasi-static compressive and torsional load tests were used to assess the desired improvement of the screw anchoring. Cadaver femur pairs served to compare the cement augmentation to the uncemented contralateral control. RESULTS: The improvement of the holding strength of the screw under static compressive and torsional load depended on the cement flow into the adjacent bone tissue. The filling with additional cement was only successful after having created a small hollow space at the screw tip with a special instrument. Consequently, under compression as well as torsion, the cement application yielded improvements from 17% up to several times as much. CONCLUSION: In the application of gliding screws in osteoporotic femoral heads, the locally limited cement application through the implant has been shown to be a biomechanical possibility to improve screw fixation.

Absorptiometry, Photon↗
PubMed1993

Laboratory comparison of the cannulated Herbert bone screw with ASIF cancellous lag screws.

The compression produced by and the resistance to pullout of the 6.5 mm cannulated Herbert screw were compared with those of ASIF headed screws. The latter were tested with and without washers and in the following sizes: 4.5 mm cortical, 6.5 mm cancellous with a 16 mm threaded segment, and 6.5 mm cancellous with a 32 mm threaded segment. Polyurethane foam was used as a substitute for cancellous bone and ASIF artificial bone for corticocancellous bone. The compression produced by a cancellous lag screw with a washer was significantly greater than that produced by a Herbert screw of equivalent size (p < 0.05). When the screws were tested using the corticocancellous composite the ASIF cancellous screw without a washer produced significantly greater compression (p < 0.05); when used with a washer the difference was highly significant (p < 0.001). The dual pitch Herbert screw is not appropriate for the management of fractures in which compression is of greater importance than the need to avoid prominence of the screw head.

Biomechanical Phenomena↗
PubMed2001

Improved bone-screw interface with hydroxyapatite coating: an in vivo study of loaded pedicle screws in sheep.

STUDY DESIGN: An in vivo sheep model with loaded pedicle screws was used, wherein each animal served as its own control. OBJECTIVES: To examine the effects of hydroxyapatite (HA) coating on the bone-to-implant interface in loaded spinal instrumentations. SUMMARY OF BACKGROUND DATA: Spinal instrumentation improves the healing rate in spinal fusion, but screw loosening constitutes a problem. HA coating of other implants has resulted in favorable effects on the bone-to-implant interface. METHODS: Nine sheep were operated on with destabilizing laminectomies at two levels: L2-L3 and L4-L5. Each level was stabilized separately with a four-screw instrumentation. Uncoated screws (stainless steel) or the same type of screws coated with plasma-sprayed HA were used in either the upper or the lower instrumentation in a randomized fashion. The animals were killed at 6 or 12 weeks after surgery. The specimens were embedded in resin, ground to approximately 10 microm, and stained with toluidine blue. Histomorphometric evaluation was carried out in a Leitz Aristoplan (Wetzlar, Germany) light microscope equipped with a Leitz Microvid unit. RESULTS: The average percentage of bone-to-implant contact after 6 weeks was 69 +/- 10 for the HA-coated screws and 18 +/- 11 for the uncoated screws (P < 0.03), and after 12 weeks 64 +/- 31 (HA-coated) and 9 +/- 13 (uncoated, P < 0.02). The average bone volume in the area close to the screw was significantly higher for the HA-coated screws at both 6 and 12 weeks. CONCLUSIONS: HA coating improved the bone-to-implant interface significantly, indicating that HA coating can become useful for improving the purchase of pedicle screws.

Animals↗
PubMed1989

[Bone screw osteosynthesis of dens fractures. Technical surgical aspects and results].

Twenty cases of Anderson and d'Alonzo type II and "shallow" type III fractures of the dens were treated by anterior screw fixation: the results were reviewed and compared with previously published results obtained in series of such fractures treated non-surgically, by posterior C1-C2 arthrodesis or anterior screw fixation. The complication rate of 25% in our series is comparable to those reported in a previously published review of studies on posterior wiring for C1-C2 arthrodesis. Three of our cases in which complications occurred (15%) were recognized in retrospect as inappropriate for the use of this technique: in one of these patients there was confirmed non-union, and the other two had markedly osteoporotic bone. A meticulous operative technique and the use of special instruments may improve the success rate. The anterior screw fixation method, however, allows for maximal post-treatment cervical motion, since it makes arthrodesis unnecessary and minimizes the degree and duration of postoperative external immobilization. It also reduces the iatrogenic trauma since an anterior rather than a posterior cervical approach is taken and supplementary bone grafting is not required. Anterior screw fixation of type II dens fractures appears to be the ideal method of treatment for these injuries, but since it is difficult to perform its use should be limited only to experienced spine surgeons with access to the appropriate surgical facilities.

Adolescent↗