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Biomedical subjects

I F Hawkins

Publications and source records attributed to I F Hawkins.

At least 73 records · Page 4Linked to original sources
PubMed1985

Retrograde nephrostomy and percutaneous calculus removal in 30 patients.

We used a new technique, retrograde nephrostomy, to provide intrarenal access for percutaneous calculus removal in 30 consecutive patients. Under fluoroscopic control, we maneuvered cystoscopically a 5F and 9F coaxial catheter pair over a guide wire into the calix selected for nephrostomy. Then, a sheathed 20 to 21 gauge needle was passed through the 9F catheter into the flank to create the nephrostomy. Eight patients were given general and 22 intravenous sedation and local anesthesia for nephrostomy placement and calculus removal. Retrograde nephrostomy and subsequent calculus removal were completed successfully in 90 and 83 per cent of the 30 patients, respectively. There were 6 complications and 3 failures among the first few patients due to inferior equipment and inexperience with the technique. Over-all, we found that retrograde nephrostomy provided reliable, precise intrarenal access and we believe that it could become an alternative technique to aid in percutaneous calculus removal procedures.

Adult↗
PubMed1985

Translumbar catheter redirection using a tip-deflector technique.

A new technique is described for reversing the direction of the catheter tip during translumbar aortography, without the need for partial withdrawal of the catheter from the aortic lumen. The method ensures optimal delivery of contrast medium at the desired level, while avoiding the risk of retroperitoneal bleeding or dislodgement during catheter manipulation.

Aortography↗
PubMed1985

Spiral exchange cannula for the occluded drainage catheter.

A technique for exchange of occluded drainage catheters or placement of two guide wires into a target using a spiral exchange cannula is described. A spiral exchange cannula with a preloaded sheath and threads at the distal end is "screwed" into the drainage catheter, and the sheath is advanced over the catheter. This method prevents dislodgment of the drainage catheter and also permits easy catheter exchange when the lumen of the drainage catheter is occluded.

Catheterization↗
PubMed1984

Radiology of giant cell tumors of bone: computed tomography, arthro-tomography, and scintigraphy.

Radiologic studies of 50 giant cell tumors of bone in 48 patients were useful in assessing the anatomic extent for planning surgical treatment. Contrast-enhanced computed tomography (CT) provided the most useful and complete evaluation, including soft tissue extent and relationship to major vessels. Angiography was useful when the extraosseous extent and vascular relationships were not entirely clear on CT. Arthro-tomography was the best way to evaluate tumor invasion through subchondral cortex and articular cartilage. Reactive soft tissues, with edema and hyperemia, were difficult to distinguish from tumor tissue on CT and angiograms. Bone scintigrams often showed intense uptake beyond the true tumor limits.

Adolescent↗
PubMed1984

Aggressive fibromatosis: evaluation by computed tomography and angiography.

Fifteen CT scans of 13 patients who had aggressive fibromatosis were generally accurate in showing the extent of disease, although the CT definition of half or more of the margins of nine lesions was poor. Fibromatosis tumors were typically isodense or slightly hypodense with muscle when no contrast medium was used, and they enhanced to hyperdense with better delineation during infusion of contrast medium. Obliterated intermuscular planes did not always signify disease extension; the relationship to bone was often obscured by beam-hardening artifact; and small blood vessels were often invisible. Arteriograms of seven of eight patients showed some hypervascularity and helped to delineate lesions and vessels that were poorly seen on CT scans. In four instances CT findings were clearer, in two instances arteriographic findings were clearer, and twice the findings were equally clear. Three of six bone scintigrams added accurate information about involvement of adjacent bones. Since fibromatosis can microscopically infiltrate beyond the margins indicated by radiographic studies and even by direct palpation at operation, the surgeon should obtain a wide margin beyond the defined tumor limits.

Adolescent↗
PubMed1984

The cerebrovascular effects of intraarterial CO2 in quantities required for diagnostic imaging.

The recent development of digital subtraction angiography (DSA) has renewed interest in the use of gases, especially carbon dioxide, as contrast agents. Both early physiologic studies and recent clinical reports suggest that arterial CO2-DSA is a safe and useful diagnostic tool in the examination of extremity circulation. The present study examined the neurologic sequelae, pathologic changes, and effects on the blood-brain barrier to intravenous Evans-Blue and horseradish peroxidase of intracarotid CO2, in albino rats. As with other forms of cerebral gas embolization, CO2 produced multifocal ischemic infarctions and disrupted the blood-brain barrier to macromolecular tracers. The site of the barrier lesion is the endothelial cell membrane, although the precise mechanisms of damage remain unknown. Caution must be urged in the use of CO2-DSA to avoid embolization of the central nervous system.

Animals↗
PubMed1984

Removal of an entangled monofilament with a Chiba needle.

A monofilament which has become entangled during an interventional procedure may be cut free by advancing a catheter over the free ends and sliding a 22 gauge Chiba needle over the monofilament. When the knot is encountered, the sharp tip of the Chiba needle cuts and releases the monofilament.

Humans↗
PubMed1984

Curved stylus for redirection of the fine-needle guide.

A new curved stylus, fabricated from a new alloy (rocket wire), can be used in fine-needle biopsy and drainage procedures after a near miss of the target. This permits reorientation of the tip of the needle into the target and obviates the need for additional passes.

Alloys↗
PubMed1984

A new deflector handle for catheter exchange.

The standard deflecting handle and deflecting wire have been modified to permit deflectors to be used as exchange wires. The spherical knobs are removed from the proximal end of the deflecting wire, and simple inserts are attached to the deflector handle. The handle can be used with deflector wires that have various length extensions (J or straight floppy tips) and with guidewires of variable stiffness.

Angioplasty, Balloon↗
PubMed1984

Percutaneous cholecystostomy in acute cholecystitis and common duct obstruction.

Percutaneous cholecystostomy was performed in 36 patients, of whom 22 patients with acute cholecystitis had decompression of the gallbladder and 14 patients with common duct obstruction had biliary decompression through the gallbladder. In almost all cases of acute cholecystitis, percutaneous cholecystostomy quickly confirmed the diagnosis and brought relief. Bile leakage occurred in one patient when catheter placement was performed under ultrasonic guidance alone; subsequent procedures were performed in a single step using an "accordion" catheter under fluoroscopic control following ultrasound localization. This technique has proved to be useful as both a diagnostic and therapeutic procedure.

Acute Disease↗
PubMed1984

The Hawkins needle-guide system for percutaneous catheterization: 1. Instrumentation and procedure.

In 1979, a new 22 gauge "skinny"-needle cannula system was introduced for combined percutaneous transhepatic cholangiography and drainage procedures. This small-bore system safely permits multiple passes when searching for small targets. Once the area of interest is entered, drainage can be accomplished with the same needle insertion by advancing either a 5 French straight Teflon or 6.5 French Teflon retention catheter over the stiff 22 gauge cannula. The distal tip of a catheter is looped using a continuous strand of monofilament, which helps to prevent catheter dislodgment. For 103 cholangiograms attempted, the overall success rate was 97%, including 95% in nondilated intrahepatic biliary tracts, with no major complications.

Catheterization↗
PubMed1984

The Hawkins needle-guide system for percutaneous catheterization: 2. Clinical experience in biliary tract and abscess drainage.

In 1979, a new, 22 gauge needle guide was introduced for combined percutaneous transhepatic cholangiography and biliary drainage procedures. In 103 biliary procedures and 29 abscess drainages using this needle guide, there were no major complications. The use of a small-volume (1-2 ml), low-pressure contrast injection followed by 24 hr of external decompression using self-retaining catheters (Cope loop, accordion) has reduced sepsis as a problem in biliary procedures. Small targets (1-2 cm abscess cavities) can be safely searched for with this 22 gauge needle guide. Two multiloculated abscesses were successfully drained by applying the surgical principle of ingress-egress irrigation catheters for infected cavities.

Abscess↗
PubMed1984

New monofilament and soft-wire baskets for stone removal.

A new-design basket for stone removal uses a standard Teflon catheter with radially positioned holes at its tip to hold either monofilament or soft wire. The strands are positioned to form a basket that will change in both size and shape simply by advancing or retracting these strands. This basket is much safer, can be changed in size during maneuvering , will transmit instruments for stone fragmentation, and can be advanced over a guide wire. It has been effective both in vitro and in the retrieval of biliary and urinary tract stones in 20 patients, several of which could not be retrieved by standard methods.

Animals↗
PubMed1984

Retrograde nephrostomy for stone removal: combined cystoscopic/percutaneous technique.

The retrograde percutaneous nephrostomy, a new technique for access to the urinary tract for stone removal, involves cystoscopic placement of a 9 French catheter into a selected minor calix, through which a sheathed 20- or 21-gauge needle is then advanced to exit at the skin. The tract is then dilated over this needle. This technique has been used successfully in 38 patients with only three complications. The technique is more reliable and less time-consuming than the standard antegrade percutaneous approach, particularly in the nondilated pelvicaliceal system. However, to avoid damage to the liver, spleen, or pleural cavity, care must be taken to ensure that the needle does not exit in a cranial direction.

Cystoscopy↗