Biomechanical properties of expander compared with conventional screws

2002 ◽  
Vol 97 (3) ◽  
pp. 346-349 ◽  
Author(s):  
Aziz Rassi-Neto ◽  
Antonio Shimano
Keyword(s):  
Maximum Load ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Intergroup Difference ◽  
Content Type ◽  
Significant Difference ◽  
Group 2 ◽  
The Comparative Study ◽  
Screw Group ◽  
Fine Print

Object. A pullout strength biomechanical study was performed in 20 fresh swine vertebral bodies in which titanium expander (Group 1) and conventional screws (Group 2) were placed. Methods. The screws were inserted into the anterosuperior portion of the anterior spine, and assessment was performed after application of loads. The expander screw is composed of two parts: 1) a cover with an external portion comprising tight thin threads; and 2) a compact internal screw inserted through the cover that allows expansion. In the comparative study between the screws in Groups 1 and 2 maximum load was assessed, and the intergroup difference was significant (p = 0.00001 [t-test]); regarding load at the elasticity threshold, a significant difference was also observed (p = 0.0063). With regard to rigidity (stiffness), there was a tendency in both groups toward significance (p = 0.069). With regard to absorbed energy in the elastic phase, statistical analysis showed a significant intergroup difference (p = 0.00439). The expander screw showed a greater load-bearing capacity than the conventional screw. Adhesion to bone in relation to the applied load and displacement was greater (significant tendency) in the expander screw group than in the conventional screw group. Conclusions. The expander screws exhibited a greater capacity to absorb energy in the elastic phase. They adhered better to bone, were easy to insert, and, if necessary, were simple to remove.

Biomechanical evaluation of cervical lateral mass fixation: a comparison of the Roy-Camille and Magerl screw techniques

2004 ◽  
Vol 100 (3) ◽  
pp. 268-276 ◽  
Author(s):  
Cédric Barrey ◽  
Patrick Mertens ◽  
Claude Rumelhart ◽  
François Cotton ◽  
Jérôme Jund ◽  
...  
Keyword(s):  
Testing Machine ◽  
Biomechanical Study ◽  
Lateral Mass ◽  
Mineral Density ◽  
Vertebral Level ◽  
Content Type ◽  
Pullout Force ◽  
Significant Difference ◽  
The Difference ◽  
Fine Print

Object. The purpose of this study was to assess human cervical spine pullout force after lateral mass fixation involving two different techniques: the Roy-Camille and the Magerl techniques. Although such comparisons have been conducted previously, because of the heterogeneity of results and the importance of this procedure in clinical practice, it is essential to have data derived from a prospective and randomized biomechanical study involving a sufficient sample of human cervical spines. The authors also evaluated the influence of the sex, the vertebral level, the bone mineral density (BMD), the length of bone purchase, and the thickness of the anterior cortical purchase. Methods. Twenty-one adult cervical spines were harvested from fresh human cadavers. Computerized tomography was performed before and after placing 3.5-mm titanium lateral mass screws from C-3 to C-6. Pullout forces were evaluated using a material testing machine. The load was applied until the pullout of the screw was observed. A total of 152 pullout tests were available, 76 for each type of screw fixation. The statistical analysis was mainly performed using the Kaplan—Meier survival method. The mean pullout force was 266 ± 124 N for the Roy-Camille technique and 231 ± 94 N for the Magerl technique (p < 0.025). For the C3–4 specimen group, Roy-Camille screws were demonstrated to exert a significantly higher resistance to pullout forces (299 ± 114 N) compared with Magerl screws (242 ± 97 N), whereas no difference was found between the two techniques for the C5–6 specimen group (Roy-Camille 236 ± 122 N and Magerl 220 ± 86 N). Independent of the procedure, pullout strengths were greater at the C3–4 level (271 ± 114 N) than the C5–6 level (228 ± 105 N) (p < 0.05). No significant correlation between the cancellous BMD, the thickness of the anterior cortical purchase, the length of bone purchase, and maximal pullout forces was found for either technique. Conclusions. The difference between pullout forces associated with the Roy-Camille and the Magerl techniques was not as significant as has been previously suggested in the literature. It was interesting to note the influence of the vertebral level: Roy-Camille screws demonstrated greater pullout strength (23%) at the C3–4 vertebral level than Magerl screws but no significant difference between the techniques was observed at C5–6.

Management of elderly patients with aneurysmal subarachnoid hemorrhage

1988 ◽  
Vol 69 (3) ◽  
pp. 332-339 ◽  
Author(s):  
Tetsuji Inagawa ◽  
Mitsuo Yamamoto ◽  
Kazuko Kamiya ◽  
Hidenori Ogasawara
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Mortality Rate ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Age Groups ◽  
Content Type ◽  
Significant Difference ◽  
Group 3 ◽  
Group 2 ◽  
Fine Print ◽  
Group 1

✓ A total of 299 patients with aneurysmal subarachnoid hemorrhage (SAH) were classified into three age groups, that is, those aged 59 years or younger (Group 1: 159 patients, 53%), those aged 60 to 69 years (Group 2: 85 patients, 28%), and those aged 70 years or older (Group 3: 55 patients, 18%). A comparison was made of the surgical indications and their overall management outcome in these age groups. The overall outcome at 1 year after SAH of Group 3 was significantly poorer than that of Group 1 (p < 0.01) or Group 2 (p < 0.01), but no significant difference could be demonstrated between Groups 1 and 2. Overall, 104 of the 299 patients died, for a mortality rate of 35%. The mortality rate by age group was 29% for Group 1, 33% for Group 2, and 55% for Group 3. Surgery was performed on 122 patients (77%) in Group 1, 56 (66%) in Group 2, and 25 (45%) in Group 3. The overall operative outcome at 1 year after SAH in Group 3 was significantly poorer than that of Group 1 (p < 0.01), but no significant difference was observed in this regard between Groups 1 and 2. The operative mortality rate of the patients in Groups 1 , 2, and 3 who were preoperatively in Hunt and Hess Grades I and II was 1%, 7%, and 22%, respectively (no significant difference). By life-table analysis the 5-year survival probability was 65% for Group 1, 60% for Group 2, and 37% for Group 3. The rate of patients surviving in good condition or in a disabled but independent condition at 1 year after SAH was 93% and no statistically significant difference in survival probability was observed among the three age groups.

Gamma knife radiosurgery for intracranial metastatic melanoma: a 6-year experience

2002 ◽  
Vol 97 ◽  
pp. 494-498 ◽  
Author(s):  
Jorge Gonzalez-martinez ◽  
Laura Hernandez ◽  
Lucia Zamorano ◽  
Andrew Sloan ◽  
Kenneth Levin ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Brain Metastases ◽  
Metastatic Melanoma ◽  
Gamma Knife Radiosurgery ◽  
Tumor Control ◽  
Karnofsky Performance Scale ◽  
Content Type ◽  
Significant Difference ◽  
The Mean ◽  
Fine Print

Object. The purpose of this study was to evaluate retrospectively the effectiveness of stereotactic radiosurgery for intracranial metastatic melanoma and to identify prognostic factors related to tumor control and survival that might be helpful in determining appropriate therapy. Methods. Twenty-four patients with intracranial metastases (115 lesions) metastatic from melanoma underwent radiosurgery. In 14 patients (58.3%) whole-brain radiotherapy (WBRT) was performed, and in 12 (50%) chemotherapy was conducted before radiosurgery. The median tumor volume was 4 cm3 (range 1–15 cm3). The mean dose was 16.4 Gy (range 13–20 Gy) prescribed to the 50% isodose at the tumor margin. All cases were categorized according to the Recursive Partitioning Analysis classification for brain metastases. Univariate and multivariate analyses of survival were performed to determine significant prognostic factors affecting survival. The mean survival was 5.5 months after radiosurgery. The analyses revealed no difference in terms of survival between patients who underwent WBRT or chemotherapy and those who did not. A significant difference (p < 0.05) in mean survival was observed between patients receiving immunotherapy or those with a Karnofsky Performance Scale (KPS) score of greater than 90. Conclusions. The treatment with systemic immunotherapy and a KPS score greater than 90 were factors associated with a better prognosis. Radiosurgery for melanoma-related brain metastases appears to be an effective treatment associated with few complications.

Gamma knife radiosurgery for metastatic brain tumors from lung cancer: a comparison between small cell and non—small cell carcinoma

2002 ◽  
Vol 97 ◽  
pp. 484-488 ◽  
Author(s):  
Toru Serizawa ◽  
Junichi Ono ◽  
Toshihiko Iichi ◽  
Shinji Matsuda ◽  
Makoto Sato ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Brain Tumors ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Small Cell ◽  
Metastatic Brain Tumors ◽  
Cell Lung Carcinoma ◽  
Content Type ◽  
Significant Difference ◽  
Fine Print

Object. The purpose of this retrospective study was to evaluate the effectiveness of gamma knife radiosurgery (GKS) for the treatment of metastatic brain tumors from lung cancer, with particular reference to small cell lung carcinoma (SCLC) compared with non-SCLC (NSCLC). Methods. Two hundred forty-five consecutive patients meeting the following five criteria were evaluated in this study: 1) no prior brain tumor treatment; 2) 25 or fewer lesions; 3) a maximum of three tumors with a diameter of 20 mm or larger; 4) no surgically inaccessible tumor 30 mm or greater in diameter; and 5) more than 3 months of life expectancy. According to the same treatment protocol, large tumors (≥ 30 mm) were surgically removed and the other small lesions (< 30 mm) were treated with GKS. New lesions were treated with repeated GKS. Chemotherapy was administered, according to the primary physician's protocol, as aggressively as possible. Progression-free, overall, neurological, qualitative, and new lesion—free survival were calculated with the Kaplan—Meier method and were compared in the SCLC and NSCLC groups by using the log-rank test. The poor prognostic factors for each type of survival were also analyzed with the Cox proportional hazard model. Conclusions. Tumor control rate at 1 year was 94.5% in the SCLC group and 98% in the NSCLC group. The median survival time was 9.1 months in the SCLC group and 8.6 months in the NSCLC group. The 1-year survival rates in the SCLC group were 86.5% for neurological survival and 68.9% for qualitative survival; those in the NSCLC group were 87.9% for neurological and 78.9% for qualitative survival. The estimated median interval to emergence of a new lesion was 6.9 months in the SCLC group and 9.8 months in the NSCLC group. There was no significant difference between the two groups for any type of survival; this finding was verified by multivariate analysis. The results of this study suggest that GKS appears to be as effective in treating brain metastases from SCLC as for those from NSCLC.

scholarly journals Biomechanical properties of the bone during implant placement

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ádám László Nagy ◽  
Zsolt Tóth ◽  
Tamás Tarjányi ◽  
Nándor Tamás Práger ◽  
Zoltán Lajos Baráth
Keyword(s):  
Bone Structure ◽  
Biomechanical Properties ◽  
Control Group ◽  
Dynamic Tests ◽  
Bone Model ◽  
Implant Placement ◽  
Significant Difference ◽  
Before And After ◽  
Group 2 ◽  
Post Hoc

Abstract Background In this research the biomechanical properties of a bone model was examined. Porcine ribs are used as experimental model. The objective of this research was to investigate and compare the biomechanical properties of the bone model before and after implant placement. Methods The bone samples were divided in three groups, Group 1 where ALL-ON-FOUR protocol was used during pre-drilling and placing the implants, Group 2 where ALL-ON-FOUR protocol was used during pre-drilling, and implants were not placed, and Group 3 consisting of intact bones served as a control group. Static and dynamic loading was applied for examining the model samples. Kruskal–Wallis statistical test and as a post-hoc test Mann–Whitney U test was performed to analyze experimental results. Results According to the results of the static loading, there was no significant difference between the implanted and original ribs, however, the toughness values of the bones decreased largely on account of predrilling the bones. The analysis of dynamic fatigue measurements by Kruskal–Wallis test showed significant differences between the intact and predrilled bones. Conclusion The pre-drilled bone was much weaker in both static and dynamic tests than the natural or implanted specimens. According to the results of the dynamic tests and after a certain loading cycle the implanted samples behaved the same way as the control samples, which suggests that implantation have stabilized the skeletal bone structure.

A COMPARATIVE BIOMECHANICAL STUDY OF THE LOOPED SQUARE SLIP KNOT AND THE SIMPLE SURGICAL KNOT

Hand Surgery ◽  
2006 ◽  
Vol 11 (01n02) ◽  
pp. 93-99 ◽  
Author(s):  
Surut Jianmongkol ◽  
Geoffrey Hooper ◽  
Weerachai Kowsuwon ◽  
Tala Thammaroj
Keyword(s):  
Ultimate Strength ◽  
Hand Surgery ◽  
Biomechanical Properties ◽  
Biomechanical Study ◽  
Skin Closure ◽  
Significant Difference ◽  
Mode Of Failure ◽  
Repetitive Loading ◽  
Slip Knot

The looped square slip knot was introduced as a technique for skin closure to avoid the use of sharp instruments in suture removal after hand surgery. We compared the biomechanical properties of this knot with the simple surgical square knot. The ultimate strength of the looped square slip knot was significantly (p = 0.015) higher than the simple surgical knot. There was no significant difference between the two knots in mode of failure. Knot slippage or suture breakage did not occur in any samples when testing security by repetitive loading. Therefore, the looped square slip knot is a safe and convenient alternative to the two-throw surgical knot for use in hand surgery.

Evaluation of endorphin content in the CSF of patients with trigeminal neuralgia before and after Gasserian ganglion thermocoagulation

1981 ◽  
Vol 55 (6) ◽  
pp. 935-937 ◽  
Author(s):  
Giuseppe Salar ◽  
Salvatore Mingrino ◽  
Marco Trabucchi ◽  
Angelo Bosio ◽  
Carlo Semenza
Keyword(s):  
Cerebrospinal Fluid ◽  
Trigeminal Neuralgia ◽  
Control Group ◽  
Gasserian Ganglion ◽  
Content Type ◽  
Group Of Seven ◽  
Idiopathic Trigeminal Neuralgia ◽  
Significant Difference ◽  
Before And After ◽  
Fine Print

✓ The β-endorphin content in cerebrospinal fluid (CSF) was evaluated in 10 patients with idiopathic trigeminal neuralgia during medical treatment (with or without carbamazepine) and after selective thermocoagulation of the Gasserian ganglion. These values were compared with those obtained in a control group of seven patients without pain problems. No statistically significant difference was found between patients suffering from trigeminal neuralgia and those without pain. Furthermore, neither pharmacological treatment nor surgery changed CSF endorphin values. It is concluded that there is no pathogenetic relationship between trigeminal neuralgia and endorphins.

Evaluation of brain-stem dysfunction following severe fluid-percussion head injury to the cat

1991 ◽  
Vol 74 (2) ◽  
pp. 270-277 ◽  
Author(s):  
Katsuji Shima ◽  
Anthony Marmarou
Keyword(s):  
Brain Stem ◽  
Content Type ◽  
Fluid Percussion ◽  
Fluid Percussion Injury ◽  
Brain Stem Injury ◽  
Group 2 ◽  
High Level ◽  
Subarachnoid Hemorrhages ◽  
Fine Print ◽  
Group 1

✓ The degree of brain-stem dysfunction associated with high-level fluid-percussion injury (3.0 to 3.8 atm) was investigated in anesthetized cats. Measurements were made of the animals' intracranial pressure (ICP), pressure-volume index (PVI), far-field brain-stem auditory evoked responses (BAER's), and cerebral blood flow (CBF). The animals were classified into two groups based on the severity of neuropathological damage to the brain stem after trauma: Group 1 had mild intraparenchymal and subarachnoid hemorrhages and Group 2 had severe intraparenchymal and subarachnoid hemorrhages. The ICP values in Group 1 were insignificantly lower than those in Group 2, while the PVI values in Group 2 were clearly lower (p < 0.05). Immediately after the injury, peaks II, III, and IV of the BAER's demonstrated a transitory and marked suppression. One Group 1 and two Group 2 animals showed the disappearance of peak V. In Group 1, the latencies of peak II, III, and IV gradually increased until 60 to 150 minutes postinjury, then returned to 95% of baseline value at 8 hours; however, the animals in Group 2 showed poor recovery of latencies. Two hours after brain injury, the CBF decreased to 40% of the preinjury measurement in both groups (p < 0.001). In contrast to Group 2, the CBF in Group 1 returned to 86.8% of the preinjury measurement by 8 hours following the injury. Changes in PVI, BAER, and CBF correlated well with the degree of brain-stem injury following severe head injury'- These data indicate that high-level fluid-percussion injury (> 3.0 atm) is predominantly a model of brain-stem injury.

En bloc laminoplasty without dissection of paraspinal muscles

2005 ◽  
Vol 3 (1) ◽  
pp. 29-33 ◽  
Author(s):  
Noboru Hosono ◽  
Hironobu Sakaura ◽  
Yoshihiro Mukai ◽  
Takahiro Ishii ◽  
Hideki Yoshikawa
Keyword(s):  
Ct Scanning ◽  
Cord Compression ◽  
Neck Muscle ◽  
Open Door ◽  
En Bloc ◽  
Cross Sectional ◽  
Content Type ◽  
Spinous Processes ◽  
Significant Difference ◽  
Fine Print

Object. Although conducting cervical laminoplasty in patients with multisegmental cord compression provides good neurological results, it is not without shortcomings, including C-5 palsy, axial neck pain, and undesirable radiologically detectable changes. Postoperative kyphosis and segmental instability can cause neurological problems and are believed mainly to result from neck muscle disruption. The authors developed a new laminoplasty technique, with the aim of preserving optimal muscle function. Methods. The present technique is a modification of unilateral open-door laminoplasty. By using an ultrasonic osteotome in small gaps of muscle bellies, a gutter is made without disrupting muscles, spinous processes, or their connections on the hinged side. Ceramic spacers are then positioned between elevated laminae and lateral masses at C-3, C-5, and C-7 on the opened side, which is exposed in a conventional manner. This new procedure was used to treat 37 consecutive patients with compression myelopathy. Postoperative computerized tomography (CT) scanning revealed a significant difference in a cross-sectional area of muscles between the hinged and opened side. The mean follow-up period was 40.2 months (range 24–54 months). Changes in alignment were observed in only one patient, and vertebral slippage developed in two. Performed at regular intervals, CT scanning demonstrated that the elevated laminae remained in situ throughout the study period. Conclusions. In using the present unilateral open-door laminoplasty technique, deep extensor muscles are left intact along with their junctions to spinous processes on the hinged side. Radiologically documented changes were minimal because the preserved muscles functioned normally immediately after the operation.

Differentiating aspects of product innovation processes in the food industry

2014 ◽  
Vol 116 (8) ◽  
pp. 1346-1368 ◽  
Author(s):  
Rao Sanaullah Khan ◽  
John Vincent Grigor ◽  
Alan G. Win ◽  
Mike Boland
Keyword(s):  
New Zealand ◽  
Manufacturing Industry ◽  
Value Added ◽  
Manufacturing Companies ◽  
Food Manufacturing ◽  
Content Type ◽  
Significant Difference ◽  
Group 2 ◽  
Innovation Processes ◽  
Group 1

Purpose – The purpose of this paper is to sketch a comparative account of NPD approaches between registered New Zealand food companies that are doing some sort of functional foods (FF) development (Group 1) and those that are not (Group 2); to generate a better understanding of differences and commonalities in their NPD approaches from resource-based view of competitive advantage. Design/methodology/approach – This paper opted an exploratory approach using a quantitative survey across food manufacturing companies in New Zealand. The primary foci of this empirical investigation were: orientation towards the NPD, innovation processes, collaborative NPD links and routes to commercialisation. Findings – The results (based on a 22 per cent response rate) show a significant difference (p<0.05) in the aims and mode of NPD between Groups 1 and 2. Further it was observed that food companies in Group 1 have significantly (p<0.05) more diverse external collaborations with broader aims to collaborate, in comparison with food companies in Group 2. Research limitations/implications – This study was conducted in New Zealand and thus generalisability of the findings may have to be interpreted carefully. Practical implications – The traditional NPD approach (independent and closed NPD), with loose intellectual property protection practices, dominates the food manufacturing industry in New Zealand. Research-oriented collaborations need to be strengthened in their scope and content to develop the innovative capabilities and capacities of small and medium enterprises (SME's) within future value-added food productions. Originality/value – This research provides the comparative narration of innovation process of food manufacturing companies with reference to FFs development.

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