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A quarterly bulletin to assist hospitals, nursing homes, and other device user facilities Issue No. 32  Fall 2000

SERIOUS INJURIES FROM MICROWAVE THERMOTHERAPY USED FOR BENIGN PROSTATIC HYPERPLASIA

by Laura Alonge

The Food and Drug Administration (FDA)issued a Public Health Notification on October 11, 2000 concerning the potential for serious thermal injury and related complications associated with the use of microwave energy to treat benign prostatic hyperplasia (BPH). The Notification also provides information that can help avoid these complications. Although the use of microwave thermotherapy for the treatment of BPH has been demonstrated to be safe and effective (over 25,000 procedures have been performed), FDA is concerned about unexpected procedure-related complications, some of which were not listed in the original labeling.

Currently marketed devices include the Prostatron (Edap Technomed, Inc.) and the Targis System (Urologix, Inc.). Dornier Medical Systems, Inc. has received approval to market its UroWave System but is not yet marketing it. FDA is working with the manufacturers to ensure that labeling and training programs address these complications.

Nature of the Problem

Since 1996, FDA has received reports of 16 thermal injuries related to microwave thermotherapy systems. Of these,10 resulted in fistula formation and 6 resulted in clinically significant tissue damage to the penis or urethra. These injuries may not be apparent at the time of treatment and may take hours or days to develop. The original labeling for these devices did not list fistula formation as a prcedure-related complication. The reported injuries required colostomies, partial amputation of the penis, and/or other therapeutic interventions. FDA has identified several factors that may have contributed to the injuries:

• incorrect placement or undetected migration of either the treatment catheter or the rectal temperature sensors;
• failure of the physician to remain with the patient throughout the entire treatment duration;
• failure to pause treatment when the patient communicated
• oversedation of the patient which compromises ability to communicate pain;
• treatment of patients who have undergone prior radiation therapy to the pelvic area;
• treatment of patients whose prostate sizes are outside the ranges specified in the labeling; and
• leakage from the balloons used to retain either the urethral catheter or the rectal temperature sensor in the correct anatomical position.

Background

Microwave thermotherapy systems are intended to heat the prostate, resulting in the necrosis of periurethral prostatic tissue and providing relief of urinary symptoms in patients with obstructive BPH. These devices heat the prostate to therapeutic levels using microwave energy delivered by an antenna contained within a specially designed urethral catheter. The catheter is designed so that when the balloon is seated at the neck of the bladder, the active portion of the antenna is positioned within the prostate. To prevent overheating, the systems circulate cooling fluid through the urethral catheter to protect the urethral tissue from excessive heat. The systems automatically vary microwave energy output during treatment, based on information supplied by temperature sensors placed posterior to the prostate within the rectum. Treatment may last from 30 to 60 minutes.

Because the catheter and/or the rectal temperature sesors can migrate during treatment, the following requirements can help ensure that this does not occur and deliver either undetected excessive heating of surrounding tissues or therapeutic heating levels to areas of the body that are not intended to receive treatment. Because the correct placement of both components is critical for safe and effective treatment, the labeling for these devices instructs the treating physician to:

• verify that the urethral catheter (and rectal temperature sensor probe, if applicable) has a working retention balloon prior to placement; and
• verify the proper position of both the urethral catheter and the rectal temperature sensors prior to and at specified time intervals consistent with the manufacturer’s recommendation for treatment.

The labeling also instructs the treating physician to:

• monitor the equipment during treatment;
• monitor the patient during treatment; and
• manually reduce or pause the microwave power if the patient experiences excessive pain or if extreme heating is observed.

Recommendations

Patient Selection
A patient for microwave thermotherapy for BPH should:

• meet the device’s indications, including the criteria for eligible prostate size indicated for the specific system being used;
• have had no prior radiation therapy to the pelvic area, because these patients are at increased risk of fitula formation and
• be chosen from specific patient populations for which safety and effectiveness of this therapy are known. This therapy is not recommended for patients with prostate cancer.

Patient Information
It is important to ensure that the patient understands the risks and benefits listed in the labeling of the specific device. He should also understand the following:

• duration of the procedure;
• level of pain or discomfort that should be considered normal;
• importance of telling the physician of any unusual pain during treatment;
• operation of any emergency stop button; and
• the need to remain as still as possible during treatment.

Physician’s Role
The physician must:

• continually supervise the procedure throughout the entire treatment period;
• verify that the retention balloons of the urethral catheter and rectal temperature sensor probe are free of leaks;
• confirm the placement of the urethral catheter and rectal temperature sensor using acceptable methods (e.g., direct visualization, ultra-sound imaging);
• constantly remember that either patient movement or component breakage may cause migration of a properly placed urethral catheter or rectal temperature sensor;
• be careful not to over sedate the patient, since his perception of pain is an important safety mechanism to ensure that the heating of the tissue is not excessive;
• never use general or spinal anesthesia;
• closely monitor the patient and the equipment throughout the entire treatment; and
• manually pause treatment if the patient complains of excessive pain or anything unusual occurs.

Laura Alonge is a biologist in CDRH’s Office of Surveillance and Biometrics

REPROCESSING OF SINGLE-USE DEVICES; LETTER FROM DR. FEIGAL

This letter may be viewed at http://www.fda.gov/cdrh/reuse/feigal092800_reuse.html

POTENTIAL FOR INJURY FROM CIRCUMCISION CLAMPS
by Sherry Purvis-Wynn, R..N., B.S.N., M.A.

The Food and Drug Administration (FDA) sent a letter on August 29,2000 to healthcare professionals to alert them about the potential for injury from two commonly used circumcision clamps, the Gomco®/gomco-type and Mogen®/mogen-type clamps. Both are widely used during circumcision to remove the foreskin while protecting the glans penis.

Although circumcision is generally a safe procedure, FDA is concerned that some serious device-related complications have occurred. FDA has received 105 reports of injuries involving circumcision clamps between July 1996 and January 2000¹. Injuries included laceration, hemorrhage, accidental penile amputation, and urethral damage.

Nature of the Problem Gomco® and Gomco-type Clamps The primary reasons for Gomco® and gomco-type clamps breaking, slipping, falling off during use, tearing penile tissue, or failing to make a tight seal are:

• reassembling by users with parts from different manufacturers; or
• having bent parts or mismatched components.

Although Gomco® and gomco-type clamps may appear to have interchangeable parts, these parts may not always be safely interchanged, because they may vary slightly in dimensions.

Mogen® and Mogen-type Clamps The primary reasons for Mogen® and mogen-type clamps leading to patient injuries are:

• the jaw gap dimensions are greater than those in the manufacturer's specifications; or
• the use of clamps inappropriately sized for patients.

In such cases, the clamp may allow too much tissue to be drawn through the opening of the device resulting in the removal of an excessive amount of foreskin and, n some cases, a portion of the glans penis.

Recommendations FDA is making the following recommendations to help avoid these complications.

General:

Before performing a circumcision procedure, examine the clamp to determine that all parts are available, undamaged, and within the manufacturer's specification

For Gomco® and Gomco-type clamps

• Either contact the device manufacturer to obtain replacement parts or discard the clamp if (1)you are unsure that a clamp component is part of the original clamp, or (2)the clamp has:
  • stripped threads,
  • a warped or bent base plate,
  • a bent arm,
  • twisted forks, or
  • a scored or nicked bell.²
• When requesting a replacement part, obtain the assurance of the manufacturer or supplier that the part ordered is compatible with the other components of your device. Do not substitute parts from different clamp manufacturers.
• Be sure to reassemble a clamp with only its own parts. Do not mix parts from different clamps, even from the same manufacturer, unless the manufacturer has assured you that the parts are interchangeable.
• If marking clamp parts to assure that they are correctly reassembled, ask the manufacturer to recommend the best way to mark them. Some marking methods may weaken the device or compromise your ability to sterilize it.

For Mogen® and Mogen-type clamps

• Ensure that the clamp being used is appropriate for the patient size. Some manufacturers have two sizes of clamps: adult and infant.
• Periodically measure the gap between the device's clamping jaws to ensure that it is within the manufacturer's specification.³ Using a device with an inappropriate jaw gap could allow the tip of the penis to be drawn through the clamp with the foreskin and be inadvertently severed or injured.

Bibliography

1. FDA MedWatch Reports, July 1992 through January 2000.
2. IPM Procedure: Circumcision Clamps, Health Devices 2000 January;29(1):22-3.
3. Hazard: Routine inspection needed for scissors-type circumcision clamps, Health Devices 1999 Mar; 28(3):115-6.
4. Hazard: Incompatibility of different brands of Gomco-Type circumcision clamps. Health Devices 1997 Feb;26(2):76-7.
5. Hazard: Amputations with use of adult-size scissors-type circumcision clamps on infants. Health Devices 1995 Jul;4 (7):286-7.
6. Hazard: Damaged Allied Healthcare Products Gomco circumcision clamp. Health Devices 1993 Mar;22 (3):154-5.

Sherry Purvis-Wynn, R.N., B.S.N.,M.A., is a nurse consultant in the Center for Devices and Radiological Health's Office of Surveillance and Biometrics

REUSE TELECONFERENCE, DECEMBER 13 2000

More information on this teleconference may be found at http://www.fda.gov/cdrh/reuse/sattel121300.html

GETTING MORE INFORMATION

If you have questions regarding either the microwave thermotherapy or the circumcism clamp article, please the Office of Surveillance and Biometrics (HFZ-510),1350 Piccard Drive, Rockville, Maryland 20850, by fax 301-594-2968,or by e-mail at phann@cdrh.fda.gov. You may also leave a voice mail message at 301-594-0650 and call will be returned as soon as possible.

FDA's postmarket safety notifications for medical devices are available on the Internet at www.fda.gov/cdrh/safety.html. Postmarket Safety Notifications can also be obtained through e-mail on the day they are released by subscribing to FDA's list server. To subscribe, visit our CDRH Mailing Lists Page.

SOURCES OF MEDICAL DEVICE CONSULTANTS

The following sources provide lists of medical device consultants who can provide assistance with meeting the regulatory requirements [such as 510(k)and PMA]of the FD&C Act.

• Food and Drug Law Institute (FDLI) 1000 Vermont Avenue, NW, Suite 200 Washington, DC 20005 http://www.fdli.org
• Canon Communications http://www.devicelink.com/consult
• Regulatory Affairs Professional Society (RAPS) 11300 Rockville Pike, Suite 1000 Rockville, MD 20852 http://www.raps.org/memb/yellow.cfm

Periodically, check our Reuse Homepage at http://www.fda.gov/cdrh/reuse/index.shtml for additions to the above sources and other important information.

REUSE MEETING SCHEDULE

• November 30,2000 Association for Healthcare Risk Management (http://www.ashrm.org/) Mt. Sinai, New York Scheduled FDA Speaker: Lily Ng
• December 4,2000 FDA Circulatory Support Advisory Panel Gaithersburg, Maryland Scheduled FDA Speaker: Barbara Zimmerman
• December 15,2000 West Virginia Hospital Association (http://www.wvha.com/) Charleston, West Virginia Scheduled FDA Speaker: Barbara Zimmerman

Remember to periodically check for upcoming events (http://www.fda.gov/cdrh/reuse/reuse-events.shtml) on the CDRH Reuse Homepage. Speaker slides from past events are also available.

REPORTING ADVERSE EVENTS TO FDA

The Safe Medical Devices Act of (SMDA) requires hospitals and user facilities to report deaths serious injuries associated with use of medical devices. Healthcare who are employed by subject to FDA's user facility requirements should follow reporting procedures established their facilities. All other providers submit their reports to MedWatch, voluntary reporting program. reports can be submitted by at 1-800-FDA-1088;by fax at 800-FDA-0178;by mail to MedWatch, and Drug Administration,HF-2, Fishers Lane, Rockville, 20857,or online at www.accessdata.fda.gov/scripts/medwatch.

Updated December 11, 2000

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