Botox Injection for Urologic Conditions

Introduction

Intravesical injection of onabotulinumtoxinA (Botox) is a great treatment option for neurogenic and idiopathic detrusor overactivity or urgency urinary incontinence refractory to behavioral therapy and medical management. Mechanism of action is the blockade of presynaptic release of acetylcholine from the nerve terminal, resulting in a flaccid paralysis of the detrusor muscle and relief of overactive bladder symptoms. Before injection, patients should be counseled on the temporary nature of Botox injection requiring reinjection every 6 to 9 months and the potential need for catheterization (either indwelling or intermittent). Studies have shown that 6% to 18% of patients with idiopathic conditions and up to 39% of patients with neurogenic conditions require temporary catheterization after Botox injection. Patients can be assured that need for catheterization is transient.

Patient Preparation

Before proceeding with injection, a urinalysis and culture must be obtained to confirm there is no urinary tract infection (UTI). Injection should not proceed when a UTI is present. The recommended dose for idiopathic overactive bladder is 100 U of onabotulinumtoxinA versus 200 U in those with neurogenic detrusor overactivity. The product should be reconstituted per the manufacturer recommendations. We typically dilute the Botox solution to 0.5 to 1 U/mL. If the injection is to proceed in the ambulatory setting, the patient is placed in the lithotomy (female) or supine (male) position and is prepped in the normal fashion as for office cystoscopy. The bladder is instilled with a dilute anesthetic (2% lidocaine solution in 30–60 mL of saline), which is left in the bladder for 20 to 30 minutes. Intraurethral lidocaine jelly is also instilled for local anesthesia. Alternatively, the procedure may be performed under general anesthesia in the operating room for selected patients.

Patient Preparation

Before proceeding with injection, a urinalysis and culture must be obtained to confirm there is no urinary tract infection (UTI). Injection should not proceed when a UTI is present. The recommended dose for idiopathic overactive bladder is 100 U of onabotulinumtoxinA versus 200 U in those with neurogenic detrusor overactivity. The product should be reconstituted per the manufacturer recommendations. We typically dilute the Botox solution to 0.5 to 1 U/mL. If the injection is to proceed in the ambulatory setting, the patient is placed in the lithotomy (female) or supine (male) position and is prepped in the normal fashion as for office cystoscopy. The bladder is instilled with a dilute anesthetic (2% lidocaine solution in 30–60 mL of saline), which is left in the bladder for 20 to 30 minutes. Intraurethral lidocaine jelly is also instilled for local anesthesia. Alternatively, the procedure may be performed under general anesthesia in the operating room for selected patients.

Procedure

Either a flexible or rigid cystoscope can be used for the injection. The authors use a flexible scope for men in a supine position and a rigid scope for women in the lithotomy position. Needles are available for both types of scope, and tip length varies between 4 and 8 mm. We use a 4-mm needle to minimize the risk of extravesical injection of onabotulinumtoxinA. In a survey of urologists performing Botox injections, important qualities of an injection needle include avoidance of leakage or perforation of the bladder wall, ease of injection, cost, sharpness, avoidance of bleeding and pain, low risk of damage to a flexible cystoscope, flexibility, and quality of the Luer lock connection. The BoNee needle by Coloplast has a 4-mm ultrafine tip that fulfills the above criteria. Other options include the Laborie needle, which has an adjustable tip length from 2 to 5 mm, as well as the Olympus flexible needle, which has a 4-mm tip. Variations of these needles are available for use in flexible as well as rigid scopes. In our practice, the Coloplast BoNee needle is used. Table 105.1 describes several commonly used needle options.

TABLE 105.1

COMMONLY-USED ENDOSCOPIC NEEDLES FOR INTRADETRUSOR INJECTION OF ONABOTULINUMTOXINA

	Supplier	Part Number	Gauge	French Size	Tip Length	Working Length (cm)
For flexible cystoscopy	Coloplast	NB1070	22	5	4 mm	70
	Laborie	DIS200	23	6	Adjustable: 2, 3, 5 mm	70
	Laborie	DIS201	23	4.8	Adjustable: 2, 3, 4, 5 mm	70
	Olympus	NM-101C-0427 MAJ-655 MAJ-656	25	6	4 mm	105
For rigid cystoscopy	Coloplast	NBI035	22	5	4 mm	35
	Cook	G14220	23	5	8 mm	35
	Cook	G15296	23	3.7	8 mm	35
	Cook	G16112	23	5	8 mm	45
	Cook	G15276	25	5	8 mm	35
	Laborie	DIS199	23	4.8	Adjustable: 2, 3, 4, 5 mm	35
	Wolf	8652.775	22	3	8 mm	31.3