fter an injury to the spinal cord, the micturition reflex may fail to function. Since t h i s reflex guards against infection in the bladder and kidneys, many paraplegics require a catheter. In addition t o contending with the psychological and sociological aspects of his trauma, the paraplegic must therefore learn t o adjust to catheterization. According to Boyarsky, 30% to 40% of paraplegics require a catheter either constantly or intermittently.' Catheterizing under sterile technique can minimize the introduction of bacteria, but continued use of the catheter tends to cause the bladder to lose its muscle tone and reduces the possibility of resuming normal bladder function. The principle of remote electronic stimulation of the nervous system has been used for several years in the form of dorsal column stimulation for pain relief and carotid sinus nerve stimulation for angina. I n 1970, Duke Medical Center, Durham, NC, initiated a new approach that activates the micturition reflex by electronic stimulation of a permanently implanted spinal electrode. Thus, the paraplegic is able to empty his bladder

A

Micturition control system for paraplegics h S / k

Self

Leslie Self is currently a nursing student at Watts Hospital School of Nursing, Durham,

NC. She has worked as a neuroaugmentation therapist at Duke University Medical Center in Durham.

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Fig 1 . The electrode consists of two insulated wires with bared, conical tips mounted on an epoxy strip. The receiver has an alternating pulse signal.

completely without the use of a catheter. The operation was devised for patients after i t was demonstrated that sacral cord stimulation of the S1-S2 level caused the bladder to empty in paraplegic dogs and cats.2 Micturition reflex implantation procedures involving one female and three male patients were reported in 1972.3 Since then, techniques have been improved and ten additional patients have received conus stimulators. This paper describes the procedures and patient care techniques presently in use. The micturition control system enables the patient to control bladder function through the use of a neuroprosthesis. The equipment consists of four separate but interrelated parts. The receiver and electrode are surgically implanted in the patient; the transmitter and antenna are used externally. The receiver is a round, sealed metal case encircled by a small receiving loop antenna (Fig 1).The case is approximately 44 mm in diameter and 15 mm thick. About the size of a half dollar, it

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weighs about 30 gm. Although the receiver houses electronic circuitry, it contains no batteries. The receiver is placed in the subcutaneous tissue on the left or right side of the patient’s waist. The electrode is connected to the receiver. It consists of two insulated platinum wires that have 1.5 mm bared conical tips mounted 2.5 mm apart on an epoxy strip. The electrode is attached to the dura of the spinal cord and secured by a Silastic-coated Dacron strip around the conus. The transmitter is housed in a case, which is slightly larger than a cigarette package (Fig 2). It contains dials that a r e s e t t o control t h e frequency, amplitude, and duration of a pulse generated by a 9-volt battery (Figs 2 and 3). The antenna consists of several turns of wire wound in a flat plane. During use, it is placed on the patient’s body over the implanted receiver, taped in place, and plugged into the transmitter. In operation, the transmitter generates a radio wave that is received by the antenna and transmitted through the

AORN Journal, June 1979, V o l 2 9 , No 7

Figure 2 Figs 2 and 3. The transmitter (top) is operated on a 9-volt battery. To begin stimulation, the patient presses the switch at the top of the transmitter (bottom), and the antenna carries current to the receiver.

Figure 3

dAORN Journal, June 1979, Val 29, No 7

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body tissue to the implanted receiver. The receiver then transmits the impulse to the electrode, which stimulates the micturition reflex and causes the bladder to produce voiding. Patient selection. The micturition reflex is the guardian of bladder and kidney function. Thus, the paraplegic with repeated bladder infections whose micturition reflex is intact is a good candidate for the micturition control system. Paraplegics with extensive scarring around the conus medullaris due to trauma are not good candidates due to the absence of the micturition reflex. Other potential candidates are those who have been paraplegic for six months to a year, who have chronic bladder infections, large or small bladder capacity, or incomplete reflex bladder emptying. The candidate should be in good general health and have good skin condition with no large decubiti. He should have no serious metabolic defects and should be able to understand use of the equipment. Female paraplegics are better candidates because women void with lower bladder pressures and have lower sphincter resistance than men. In the selection of these patients, a preoperative clinical evaluation is the final determination of candidacy. Preoperative assessment and care. After admission and before the patient is selected for implantation, he and his family are briefed by the neurosurgeon and nurse about the procedure. The patient and family are told by the neurosurgeon that the implantation is to enable the patient to be catheter free, thus diminishing the chances of urinary tract infection. They are informed that the patient’s preoperative and postoperative stay will be 10 to 20 days, depending on the procedure and the patient’s postoperative course. The preoperative clinical evaluation and postoperative testing procedures are

also explained to the patient. The importance of following the prescribed postoperative routine, involving daily urine analysis and fluid intake and output, is particularly stressed. Contraindications to having the implant, such as wound infections, incomplete emptying of the bladder, or complete failure of the system, are discussed. The patient is told that his catheter will remain in the bladder until he has recovered from surgery and sutures have been removed; then stimulation will begin. We tell him this may be about a week after implantation. The patient is told that even after stimulation has begun, the catheter will remain in place temporarily and he will be responsible for clamping off his catheter to increase the bladder volume. A nurse will be present when he voids to record amount voided, residual, and autonomic responses. Cost of the operation and implant is approximately $3,000. The internal and external equipment are shown to the patient by the nurse. He or she explains how the equipment operates and answers any questions the patient may have. Preoperative clinical evaluation. The preoperative clinical evaluation consists of a urological examination that includes cystogram to eliminate patients with reflux, cystoscopy, cystometrograms and urodynamics to determine bladder capacity, intravenous urogram, urinalysis, and urine culture. The patient’s serum electrolytes and blood urea nitrogen must be examined to evaluate renal function, and plain spinal x-rays and a myelogram are done to confirm that the conus medullaris has not been injured. On the basis of these preoperative tests, the physician determines whether or not the patient is a candidate for implantation. If the patient is identified as a poten-

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Fig 4. Prior to implantation, the patient’s back is prepared and draped; two 18-gauge spinal needles are introduced at the T11 - L 1 level.

tial candidate, he is taken to the operating room for percutaneous stimulation of the lumbosacral area. The neurosurgeon and nurse are present during the procedure, and a n anesthetist is on stand-by. The patient remains awake during the procedure. Muscle relaxors are not administered since relaxors limit t h e somatic and bladder responses. An indwelling catheter is inserted and used to measure bladder pressures. The patient should be positioned on his side so he is not lying on his bladder. The surgeon then identifies T11- T12 L1 using x-ray control. The back is prepared and draped; mepivacaine 1% is used as the local anesthesia (Fig 4). Two 18-gauge spinal needles are introduced a t the T11-L1 level after premeasurement of the electrodes to the point where they will touch the posterior aspect of the dorsal part of the cord. When clear spinal fluid is obtained, a small pacing catheter is introduced through the needles to lie on the dorsal surface of

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the cord. An amount of Ringer’s solution equal to the patient’s bladder capacity (determined by previous urologic studies) is introduced into the bladder when i t is time for stimulation. Stimulation is carried out with the two stainless steel electrodes in place. Using the Grass stimulator, current is introduced through t h e electrodes. Pressures are watched and recorded. This procedure, using a gauge transducer and polygraph to measure bladder pressures, indicates to the surgeon whether or not the conus medullaris is still intact. If bladder pressures correspond to those shown in figure 5, the patient is considered to be a candidate for a permanent implant. During the preoperative procedure, the nurse accurately records all objective and subjective patient responses. Anticipated patient reactions a r e sweating, headache, penile erection in males, and motor and autonomic reactions. The nurse talks with the patient to detect his subjective sensations

AORN Journal, June 1979, V o l 2 9 , No 7

12-11-73

Romp

Stimubtion

-Lot

M.J. 19y.o

Perculoneous Stimulotm of the Corn

25$L, [ 10mmHg 5 Sec. 3V

60-0t5v -15-01

5V

-30-01

15V

Fig 5. These normal bladder pressures are compared to those of the patient. I f they correspond, the patient is considered a candidate for permanent implantation.

and to alleviate his apprehensions. Implantation. After two or three days’ rest, the patient is taken to the operating room for permanent implantation. The patient receives a general anesthesia. No muscle relaxors are given to insure good bladder tone. A catheter has been placed in the bladder previously. After the patient is placed in a prone position, the catheter is again connected to the transducer for polygraph recording of bladder pressures. The lower thoracic and lumbar spine are surgically prepared and draped. A midline incision is made over the T11 through L1 spinous processes. A total laminectomy is carried out, exposing the dura in this area. The dura is opened and retracted to expose the conus and nerve roots at this level. The nerve roots are separated from the conus carefully. Small numbers are cut out and placed along this area to identify the location where the greatest bladder pressure is obtained. The bladder is filled with Ringer’s solution and bipolar stimulation is begun. By stimulating various

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parts along t h e conus, the greatest bladder pressure is determined. A bipolar electrode is then introduced into the spinal cord, and an alternating pulse receiver is implanted in a subcutaneous pocket in the left anterior abdominal wall. The pressures are again tested, using the patient’s own transmitter. The wounds are closed, and dry sterile dressings are applied. The patient is then taken to the recovery room for postoperative care. Postoperative cure. On the unit, nursing personnel are briefed about the use and function of the bladder stimulator and told that stimulation will begin after sutures are removed. Postoperative care of the implant patient is the same as that of a laminectomy patient. The only difference is that the patient is not positioned on the side of the receiver until the wound has healed and initial stimulation has been carried out by the physician. It is the nurse’s responsibility to help the patient with stimulation. Every three to four hours, the nurse must unclamp the catheter for the bladder to empty while stimulating. The amount voided with stimulation should be carefully recorded. Stimulation should not exceed 60 seconds. Two or three stimulations can be carried out in succession with a rest interval of one or two minutes. Since the stimulation is not carried out a t night, the nurse should unclamp the catheter leaving the bladder open to drain. In the morning, the nurse should make certain t h e patient’s catheter is again clamped for the day’s session. A written record of the times of stimulation and the amounts voided is kept by the nurse. This is an important record and should be kept accurately, noting any other effects the stimulator may have on the patient. Other possible effects include motor system: hypertrophy of leg muscles; reduced spasticity, bowel

AORN Journal, June 1979, V o l 2 9 , No 7

movement autonomic nervous sytem: piloerection; sweating and skin temperature; elevation penile erection; autonomic and motor reactions psychological: Once catheter free, the patient may anticipate more normal life activities, thus improving motivation for rehabilitation other: calcium metabolism, hormonal changes. After the catheter is removed, the nurse is responsible for noting intake and output on the patient's records. After stimulation, the patient should be catheterized and the residual measured. This does not have to be done aRer every session, but it is important after stimulation is first begun to determine how much residual is left in the bladder. The residual should decrease as the patient learns how to operate his stimulator more accurately and t h e bladder volume is increased. Physical therapist personnel also assist the patient in the physical therapy program after surgery. Discharge. On discharge, the patient is briefed by the nurse about his transmitter. He is told that with a weak battery he may fail to empty his bladder completely, thus enabling infection to occur. The patient's responsibility to keep a supply of fresh batteries available is stressed. The patient is advised to set up a stimulation schedule that is convenient to him a t approximately the same time each day. He is cautioned about going for long periods of time without stimulation. The patient is also instructed to note any other effects the stimulation might have. He is given the telephone numbers and addresses of the neurosurgeon and the system manufacturer, and a n appointment is made for the patient to return in three weeks. Follow-up. The patient is encouraged to keep his appointments for return visits. When the patient returns, he is

given a urological evaluation, including checks for infection. T h e patient's t r a n s m i t t e r a n d a n t e n n a a r e also checked to make sure the equipment is in good working order. During postoperative visits, t h e nurse communicates with the patient to determine how, if in a n y way, t h e stimulator has changed his life. Reported urological improvements are controlled, daily emptying of bladder; good bladder contraction with voiding; low urinary residuals; freedom from catheter; reduced bladder infections; reduced renal complications; erection in the male; and control of bowel movement. Our patients' psychological responses to the effects of the implant have been of great interest. All patients have developed the ability to use the device, and most have experimented with a variety of stimulus patterns without apprehension. From the patient's point of view, perhaps the most significant improvement results from his ability to void a t will. Because of this, patients have become more mobile and more independent. Several have returned to school or college and have graduated. Others have married and found jobs. One young man is successfully employed in a state government office. In general, families have reacted favorably. Witnessing another family member's increased independence and enhanced prospect for rehabilitation has had positive psychological effects.

0

Notes 1. S Boyarsky, The Neurogenic Bladder

(Baltimore: Williams and Wilkins, 1976) 217. 2. H Friedman, B S Nashold, Jr, P Senichal, "Spinal cord stimulation and bladder function, normal and paraplegic animals," Journal of Neurosurgery 36 (1972) 430-437. 3. E T Boone, L H Self, "Nursing care of the paraplegic using an experimental electronic spinal neuroprosthesis to activate voiding," Journal of Neurosurgical Nursing 4 (1972) 61-74.

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Micturition control system for paraplegics.

fter an injury to the spinal cord, the micturition reflex may fail to function. Since t h i s reflex guards against infection in the bladder and kidne...
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