Metal Hook Research Articles

Bond strength of fiber-reinforced composite bars for orthodontic attachment.

Long fiber-reinforced composites (FRC) have been shown to have enhanced mechanical properties that allow their use in orthodontic appliances as bars that join teeth to form either anchorage or active units. This study was designed to determine if the bonding of an orthodontic attachment has sufficient strength to withstand loading during clinical use. The experimental model consisted of a hydroxyapatite stone that simulated enamel, FRC bars, and a bonded metal hook. Three specimen types were compared: (1) a metal hook-pad (the control), (2) a woven FRC with a hook-pad, and (3) a unidirectional FRC with a hook-pad. Loads were applied both parallel and at 90 degrees to the tooth surface. Under no condition was the FRC pad combination weaker than the control pad. Under some loading conditions, the loads before failure were as much as 3 times greater than those for the control. The lowest strength was found with loads at 90 degrees to the tooth surface for all 3 types. Failure normally occurred in the FRC and rarely at the bracket or tooth interface. The excellent bonding of the orthodontic attachment to the FRC and the high strengths of the FRC attachment combination demonstrate the ability to form connecting bars between teeth for either anchorage or active segmental movements. These bars offer advantages in simplicity in treatment by reducing the need for some bands, attachments, or wires.

An operative method for surgical revision of a late failure after endovascular repair of an abdominal aortic aneurysm

Endoleak is a well-recognized complication of endovascular aortic exclusion stent-grafts. The Vanguard device is anchored into the proximal aorta by an expandable stent surmounted by a circular array of metal hooks. Attempted removal of the whole prosthesis may therefore be technically difficult and result in damage of the aortic wall. Surgery for endoleak may be complicated and carry a mortality rate of 20% to 40%. We describe a simple surgical technique for repair of endoleaks associated with a Vanguard stent-graft, which would be applicable to other such devices. This method involves minimal disruption of the proximal stent and avoids problems that may arise from an attempt to completely remove the endovascular device. (J Vasc Surg 2001;34:357-9.)

A CASE OF SIGMOID COLON PERFORATION FOLLOWING INGESTION OF A PARTIAL DENTURE

We report a case of perforation of the sigmoid colon due to an accidentally swallowed partial denture. A 63-year-old man was seen at the hospital because of an accidental swallowing of a partial denture on February 10, 1996. Simple abdominal X-ray examination showed that the denture was in the stomach. Endoscopy did not reveal a foreign body in the stomach. On the next day, the denture passed into the jejunum. Expectant management was performed because he had no symptoms. Four days later the patient was admitted to the hospital because of a lower abdominal pain. It was impossible to take it out under colonoscopy. Immediately after the colonoscopy, the abdominal pain was intensified and we found the rebound tenderness by abdominal palpation. Under a diagnosis of perforation of the sigmoid colon, an operation was carried out. There was perforation of the sigmoid colon with the metallic hooks of the denture protruding through the wall of the intestine. The patient underwent a resection of the sigmoid colon by about 25cm with end-to-end anastomosis. Postoperative course was uneventful. The patient was discharged from the hospital 3 weeks after the operation.

Benign and malignant esophageal strictures: treatment with a polyurethane-covered retrievable expandable metallic stent.

To evaluate the clinical effectiveness of a polyurethane-covered, retrievable, self-expandable metallic stent and hook catheter in the treatment of esophageal strictures. Stents were constructed of 0.4-mm stainless steel wire in a cylindric zig-zag configuration of six to nine bends. Four to eight stents were connected in tandem by dipping in a polyurethane solution. A nylon loop was hooked inside to each bend of the proximal portion of the stent and strung with a thread. Under fluoroscopic guidance, 22 stents were placed in 16 patients with a malignant stricture and five patients with a benign stricture. The stent was removed with a hook catheter 2 months after placement in patients with a benign stricture and when complications occurred in patients with a malignant stricture. All patients had dysphagia with ingestion of soft foods or liquids. Stent placement was technically successful and well tolerated in 20 patients. In one patient, the stent was misplaced but relocated successfully. After stent placement, all patients were able to ingest solid and/or soft foods without dysphagia. After stent removal, strictures showed improvement but recurred in two patients. Use of polyurethane-covered, retrievable expandable stents seems to be a feasible and effective method of treatment of benign and malignant esophageal strictures.

A spider hits the eye

To determine the necessary medical care and permanent ocular damage of a particular type of preventable ocular trauma, an observational study of 22 patients referred to the University Hospital Nijmegen (1983-1993) with eye injuries caused by the accidental release of tightened elastic straps of the so-called "spider' design was performed. Although the traumatized eyes of the 22 patients could be saved from blindness by extensive medical and surgical treatment in the majority of cases, 13 patients (59%) had residual permanent visual impairment (visual acuity < or =6/10, or aphakia) at the end of the follow-up period. Three of them had lost the perception of light in the involved eye; one painful blind eye had to be removed. It is concluded that elastic straps with free-end metal hooks should not be used to secure luggage because of the potential risk of irreversible damage to the eye.

Ultrastructural studies of cerebral vascular spasm after cardiac arrest-related global cerebral ischemia in rats.

The present investigation was undertaken to study the ultrastructural morphology of brain blood vessels during vasospasm following total cerebral ischemia. Global cerebral ischemia was produced in rats by compression of the cardiac vessel bundle (i.e., cardiac arrest) using a metal hook that was introduced into the mediastinum. Ischemia lasted for 10 min with blood recirculation for 6, 12 and 24 h. Rat brains were perfusion-fixed and regions from the cerebral cortex and associated leptomeningeal vessels were evaluated by scanning and transmission electron microscopy. We noted three general vasoconstrictive responses in vessels of various sizes including veins and arteries. These alterations related to the smooth muscle cell arrangement associated with each constricted vessel including a circumferential, and longitudinal arrangement, or a combination of both types. Other features in the three types of vasoconstricted vessels included thickening of the vessel basement membranes with increased endothelial microfilaments and vesicular profiles. Our studies present evidence that ischemia of 10-min duration with blood reflow for 6, 12 and 24 h produces profound and variable vasospastic changes in some but not all vessels. These vascular alterations are thought to be caused in part by vasoactive substances released both by endothelial and blood cells and by perivascular cellular elements in response to the ischemic episode.

Ocular Injuries Caused by Elastic Cords

To the Editor. —We read with interest the article by Nichols et al 1 in the March 1991 issue of theArchives. They reported the injuries of five patients with ocular trauma due to elastic cords with attached metal hooks. Two of their patients suffered penetrating ocular injuries, and three had final visual acuities of 20/200 or less. We performed a similar retrospective review of ocular injuries due to elastic cords in patients who presented to either the Albany (NY) Medical Center Hospital or the practice of G. Robert Hampton, MD, Syracuse, NY, from January 1987 through December 1990. The findings in our larger series of 11 patients, with a longer follow-up period of up to 48 months, are summarized in the Table. The median age of our patients was younger (26 years), and three women were among the injured. In addition to securing articles to the roof of an automobile,

Ocular Injuries Caused by Elastic Cords

Five patients with ocular trauma due to elastic cords with attached metal or plastic hooks were evaluated over a 13-month period. Injuries included hyphema, angle recession, lens subluxation, choroidal rupture, vitreous hemorrhage, retinal detachment, and scleral rupture. Two patients suffered penetrating ocular injuries, and three patients had final visual acuities of 20/200 or less. This series emphasizes the potential severity of ocular injury due to these commonly used devices and reiterates a modification in design that might decrease the likelihood of accidental trauma from elastic cords.

Instruments for transnasal brain removal during embalming by the ancient Egyptians

From the Mook—Collection in Munich 81 skulls and 7 complete heads of mummies found around Thebes and Abydos and dating from 1500–1000 BC were examined by fiberendoscope and operation microscope. Especially the nasal cavities and the ethmoidal perforations were studied through which the ancient moidal perforations were studied through which the ancient Egyptian embalmers removed the brain in the process of mummification. In many skulls these ethmoidal perforations had been nicely and meticulously prepared and we called in question whether this could be achieved merely by means of a metal hook as been described by Herodotus. We saw four different sites of the artificial foramina in the ethmoid. 22 perforations were symmetrically located in the ethmoid, 12 predominantly in the right ethmoid, 49 prediminantly in the left ethmoid and 5 perforations in the sphenoid. We present a new concept about the transnasal approach to the cranium, based on experiments in fresh cadavers in which we were able to remove the brain through the nostril by means of a simple rod of bamboo partially wrapped with moistened linen bandages. This technique of brain removal could during the process of mummification.

Foreign bodies in the air and food passages.

Foreign bodies of the aerodigestive tract have been recognized for centurles. Before the early 20th century, foreign body aspiration or ingestion often meant prolonged illness and death. 1 Prior to the advent of modern endoscopy, bronchotomy was the primary method of laryngotracheo-bronchial foreign body removal, and blunt metallic hooks, wire nooses, esophageal forceps, and pieces of linen attached to a piece of whalebone were used to extract foreign bodies from the esophagus. 2 Not surprisingly, Weist, in 1882 (as cited by Clerf 2 ), reported a 27.4% death rate for patients undergoing bronchotomy v a 23.2% mortality for those who were not treated. In 1911, LeRoche (as cited by Clerf 2 ) reported the use of a rigid esophagoscope for removal of sharp foreign objects. It was Chevalier Jackson, however, who developed and refined aerodigestive endoscopy. By 1936, he was able to report a decrease in mortality from foreign bodies from 24% to 2% and a 98% success rate for bronchoscopic removal. 1 Although there have been marked changes in anesthesia, equipment, and endoscopic teaching since Jackson9s time, his remarkable record of success has not been significantly improved upon. The mortality for all recent series is now well below 1%, mainly due to improved anesthesia, instrumentation, and medical therapy of the suppurative complications.

Foreign Bodies in the Air and Food Passages

Foreign bodies of the aerodigestive tract have been recognized for centurles. Before the early 20th century, foreign body aspiration or ingestion often meant prolonged illness and death.1 Prior to the advent of modern endoscopy, bronchotomy was the primary method of laryngotracheo-bronchial foreign body removal, and blunt metallic hooks, wire nooses, esophageal forceps, and pieces of linen attached to a piece of whalebone were used to extract foreign bodies from the esophagus.2 Not surprisingly, Weist, in 1882 (as cited by Clerf2), reported a 27.4% death rate for patients undergoing bronchotomy v a 23.2% mortality for those who were not treated. In 1911, LeRoche (as cited by Clerf2) reported the use of a rigid esophagoscope for removal of sharp foreign objects. It was Chevalier Jackson, however, who developed and refined aerodigestive endoscopy. By 1936, he was able to report a decrease in mortality from foreign bodies from 24% to 2% and a 98% success rate for bronchoscopic removal.1 Although there have been marked changes in anesthesia, equipment, and endoscopic teaching since Jackson's time, his remarkable record of success has not been significantly improved upon. The mortality for all recent series is now well below 1%, mainly due to improved anesthesia, instrumentation, and medical therapy of the suppurative complications.

Rat surgery board.

Our microsurgery laboratory needed a number of surgical rat boards, and considering the expense of the ones already on the market, we decided to make our own. A 14 in x 10 in board was cut from a large Plexiglas sheet. Suction cups with metal hooks were used to hold the rat in place. We found this board to be less expensive and also very versatile.

Application of enamel adhesives in oral surgery

Intermaxillary fixation with enamel adhesives was established in several patients. The adhesives were used to attach a metal hook to the tooth surfaces and, in some cases, hooks were developed from the adhesive material. It appears from this preliminary experience that the adhesives can be successfully used for intermaxillary stabilization in certain cases. The advantages and disadvantages of the technique are discussed.

TREATMENT OF THE LIP AND CHEEK IN CASES OF FACIAL PARALYSIS

A new simple method of supporting the lip and cheek in cases of Bell's palsy or facial paralysis has been found to be successful in a number of instances. It is necessary to give this support to prevent the droop and loss of tone that is so characteristic of these tissues in facial paralysis. This method consists in cradling the lip and cheek in a translucent plastic support and connecting that support by rubber band tension to a metal hook that is fastened to the last upper molar on the affected side (fig. 1). The lip support or cradle (A-B) is the part that actually lifts the lip and cheek under tension from the rubber hand. It consists of two flanges and a connecting bar that is shaped to conform to the closed lips (fig. 2). The flanges should be large enough to keep the tissues from bunching at the

A SIMPLE STERILIZER FOR EMERGENCY AND COUNTRY WORK.

It is one thing to prepare for operative work with the modern pressure sterilizer and other conveniences of the hospital; it is quite another thing to prepare for the same work in a private home, perhaps on a farm at a distance from the operator's office. The device offered is purposely presented in a crude form to show what may be done under such circumstances when the element of time is important. An instrument maker could give us a more sightly instrument. All that is required is a piece of No. 9 or 10 wire, a sheet of wire netting, four cords for suspension and an equal number of metal hooks. In this case poultry netting was used, the cords were wire picture-cord, and the hooks were ordinary picture hooks. But any strong cord will answer and a hook may be speedily fashioned from sheet tin or iron. The wire