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Biomedical subjects

H G Zegel

Publications and source records attributed to H G Zegel.

At least 19 recordsLinked to original sources
PubMed1998

Paraspinal ultrasonography: lack of accuracy in evaluating patients with cervical or lumbar back pain.

This study evaluates the ability of paraspinal ultrasonography to identify abnormal echogenicity in patients with cervical or lumbar back pain, or both. Paraspinal ultrasonography was performed on 82 subjects, including 23 asymptomatic controls. Echogenicity in the region of nerve roots and facets was assessed. Readings were correlated with location of patients' symptoms, if any. Receiver operating characteristic analysis demonstrated that evaluation of nerve roots by all four readers did not differ significantly from chance (0.07 < P < 0.99). Specificities ranged from 0 to 0.68. Kappa values were 0.06 for cervical and -0.06 for lumbar spine. Ultrasonography was unable to demonstrate abnormal echogenicity adjacent to facets in symptomatic patients. Paraspinal ultrasonography is neither accurate nor reproducible in evaluating patients with cervical and lumbar back pain.

Adolescent↗
PubMed1998

Intraoperative ultrasonographically guided cryoablation of renal masses: initial experience.

The purpose of this study was to evaluate the feasibility of intraoperative ultrasonography to guide cryoablation of renal masses. Renal cryoablation was performed on six patients with solid renal tumors. Under ultrasonographic guidance, cryoprobes measuring 3 mm in diameter were placed into the renal tumor parenchyma or into surrounding normal parenchyma. Intraoperative ultrasonography accurately delineated tumor size, cryoprobe placement, and depth of freezing. An echogenic interface was generated by the marked impedance differences at the junction of the normal renal parenchyma and frozen tissue. In addition, intraoperative ultrasonography identified a total of nine additional lesions in three patients that were not detected by preoperative imaging. These lesions also were treated cryosurgically during the same operation. There were no deaths. The patients have been followed with clinical and laboratory assessments as well as with MR imaging or CT scanning, and all have remained tumor free 3 to 22 months postoperatively. Ultrasonographically guided renal cryoablation is a feasible technique for treating malignant renal tumors while preserving renal parenchyma. Long-term follow-up studies in a larger series of patients are required to determine the true efficacy and safety of this procedure.

Aged↗
PubMed1997

Value of radiography in diagnosing complications of cardioverter defibrillators implanted without thoracotomy in 437 patients.

OBJECTIVE: This study evaluated the usefulness of radiography in assessing the frequency and cause of complications of nonthoracotomy-implanted cardioverter defibrillators. MATERIALS AND METHODS: Between May 1992 and December 1995, 437 consecutive patients at our institution underwent cardioverter defibrillator placement. Routine follow-up included external device testing at 6 weeks after placement and every 3 months thereafter. Chest radiographs were obtained immediately after placement, annually, and at the time of any suspected complication. Retrospective review of radiographs and medical charts was done for all patients with clinical complications. RESULTS: Forty-five complications (10%) were clinically diagnosed: lead or patch fracture in fifteen (33%) patients, electric lead dysfunction in eight (18%), infection in eight (18%), lead retraction in six (13%), patch fold in two (5%), hematoma in two (5%), and other complications in four (9%) patients. Eighteen complications (40%) were radiographically evident. Lead retraction, hematoma, patch fold, patch migration, and the twiddler syndrome were radiographically confirmed in 100% of cases. The average time for these complications to be detected was 68 days; 92% were detected within 23 days. Conversely, only four (27%) lead fractures, one (13%) electric lead dysfunction, and one (13%) infection were radiographically confirmed. These latter complications were discovered an average of 579 days after cardioverter defibrillator placement. CONCLUSION: Radiography plays a secondary role in the diagnosis of cardioverter defibrillator complications and is particularly limited beyond 1 month after placement. Radiographs may be helpful in the first month after placement because early complications are the most radiographically apparent.

Aged↗
PubMed1993

Cardioverter-defibrillator systems implanted without thoracotomy: radiographic findings.

Ventricular arrhythmias are the primary cause of sudden death from heart disease in the United States. In the past decade, management of these arrhythmias has been revolutionized by the development of implantable cardioverter-defibrillators (ICDs). Earlier devices required thoracotomy for implantation (Fig. 1). Complications associated with the earlier devices include pneumothorax, pleural effusion, mediastinal infection, and, notably, crinkling of the patch and migration. The morbidity of median sternotomy has led to the development of ICDs that can be implanted without thoracotomy. We illustrate the normal radiographic appearance and complications of two recently developed ICD lead systems.

Adolescent↗
PubMed1991

Retained anchoring suture after removal of a Cope-loop drainage catheter: use of the retract-and-cut method.

A method is described for managing retention of the anchoring suture within the tract after a Cope-loop drainage catheter has been removed. In the authors' experience, the overwhelming majority of such strings can be extracted by sliding a dilator over the suture and using gentle manipulation at the site of adherence. However, in 12 patients, this technique was not successful. In these patients, the retract-and-cut method was used: The suture is pulled taut and cut at the surface, allowing it to retract into the tract. This provided a safe and simple solution for this complication.

Bile↗
PubMed1991

Repair of Achilles tendon ruptures with a polylactic acid implant: assessment with MR imaging.

An investigational tendon repair device composed of a polymer of lactic acid (PLA) is currently undergoing multicenter clinical trials for use in repairing rupture of the Achilles tendon. The advantages of the PLA device include high tensile strength and the induction of a rapid proliferative tissue response resulting in a shorter rehabilitation period than with conventional surgical repair. We reviewed 16 MR examinations performed in 10 patients 3-35 months after repair to characterize the MR appearance. All 16 T1-weighted sagittal images revealed a thickened fusiform tendon with streaks of moderate signal within the tendon corresponding to the PLA device and its surrounding collagenogenic response. The double-echo T2-weighted axial images at the mid tendon level demonstrated progressive changes in the signal pattern of the central portion of the tendon that reflected the maturation of the healing tendon. All tendons repaired with PLA implants were uniformly hypertrophied relative to the contralateral normal side because of the induced proliferative collagenogenic ingrowth. Two follow-up MR examinations were performed in six patients and showed mean reductions in tendon caliber of 24% and 30% at the mid and inferior levels. MR imaging of the Achilles tendon repaired with PLA implants shows a diffusely thickened tendon with streaks of signal within the tendon that distinguish it from tendons repaired by conventional techniques.

Achilles Tendon↗
PubMed1990

Evaluation of the lacrimal apparatus with digital subtraction macrodacryocystography.

Patients who suffer from epiphora can benefit from reconstructive surgery in many cases of obstructive and nonobstructive lesions of the lacrimal apparatus. We describe our technique of digital subtraction macrodacryocystography (DSM) and discuss its efficacy in the evaluation of various abnormalities involving the lacrimal drainage pathway. A variety of pathologic conditions of the lacrimal apparatus are portrayed. DSM is an accurate, easy to perform, but relatively unrecognized method of anatomic localization of obstructive lesions within the lacrimal drainage system.

Dacryocystitis↗
PubMed1981

Ultrasonic characteristics of bilomas.

The ultrasonic characteristics of bilomas are reviewed in five patients, one of whom was also studied with computed x-ray tomography. Certain features not previously reported should aid in differentiating bilomas from other intra-abdominal fluid collections.

Adult↗
PubMed1981

Normal left renal vein mimicking left renal artery aneurysm.

On transverse ultrasound scans a small number of patients with a paucity of retroperitoneal fat show an initial false impression of a left renal artery aneurysm due to the confluence of two normal findings. The left renal vein is unusually prominent from the hilum of the left kidney to the area between the superior mesenteric artery and the aorta; and part of the normal aortic wall, adjacent to the left renal vein, is incompletely imaged. Explanations for the prominence in the left renal vein and the partial visualization of the aortic wall are discussed, and various maneuvers that allow for accurate identification of both are described. The use of this analysis should prevent the incorrect diagnosis of a left renal artery aneurysm, which might lead to more invasive diagnostic procedures.

Aneurysm↗
PubMed1981

Percutaneous nephrostomy: comparison of sonographic and fluoroscopic guidance.

Both sonography and fluoroscopy have been recommended for renal localization and needle guidance for percutaneous nephrostomy. The respective efficacies of both methods have been compared in a prospective study of 88 patients undergoing percutaneous nephrostomy by the catheter over guide wire technique. Fifty-five patients had initial puncture using either an A-mode (42 patients) or real time (13 patients) sonographic aspiration transducer, while 33 patients had a single plane vertical beam fluoroscopy for puncture guidance. The use of either sonographic method for the initial needle puncture significantly reduced the number of puncture attempts (p = 0.000004) and potential iatrogenic risk, eliminated the need for intravenous administration of contrast material, allowed initial safe introduction of a large caliber needle, and decreased the length of time needed to perform the procedure.

Drainage↗