Substitution urethroplasties with free graft buccal mucosa

OBJECTIVE: To present our experience with free graft buccal mucosa substitution urethroplasties. METHODS: Between June, 1992 and December, 1997, we performed 18 urethroplasties with buccal mucosa in 17 patients (double urethroplasty in the same stage in one): 8 for the repair of urethral strictures, 9 for the repair of hypospadias cripples and one for epispadias repair, in an exstrophic boy. Only 3 patients had not undergone previous reconstructive operations. The mean age was 26.2 years (range 10-69). In 8 cases we harvested the graft from the inner cheek and in another 8 cases from the inner lower lip; in two cases we combined mucosa from the cheek and from the lip. In 14 patients we managed to preserve the urethral roof and the buccal mucosa was grafted as an onlay patch; 4 patients underwent full circumference tube replacement. The median follow-up of the series was 17.8 months, ranging from 1 month to 5.5 years. RESULTS: In 15 out of 18 repairs (83.3%) the final outcome was satisfactory, while in three cases the graft failed and reoperation was necessary. In 10 of the 15 successful urethroplasties the end result was excellent: first intention healing no complications or sequelae; in the other 5, although the end result was good, fistulae requiring surgery for closure developed in 2 and meatal stenosis requiring autodilations in three patients. The best results were obtained in strictures of the bulbar urethra secondary to trauma with 100% success rate. In hypospadias the success rate was 77.7%. Onlay patch grafts never failed, with 10 out of 14 excellent results. Three out of 4 tubed grafts failed. CONCLUSIONS: At short and medium term, the free grafts of buccal mucosa yield results comparable to those of other epitheliums in use for urethral repair, thus increasing the choice of techniques at our disposal for one-stage repairs. We consider that it is best suited for long strictures of the bulbar urethra.     

Does prostate transitional cell carcinoma preclude orthotopic bladder reconstruction after radical cystoprostatectomy for bladder cancer?

PURPOSE: We determined if urethral preservation and orthotopic bladder replacement in patients with transitional cell carcinoma within the prostatic urethra or prostate placed these patients at risk for urethral recurrence or death. MATERIALS AND METHODS: The clinical course of all patients undergoing urethral preservation and orthotopic bladder replacement was reviewed. The urethra was sacrificed only if the distal prostatic urethral margin was positive for transitional cell carcinoma. The pathological T stage and the grade of the primary malignancy, local recurrence, site of recurrence (urethral, pelvic, distant) and death were documented. RESULTS: Of 81 patients 70 were evaluable (June 1996) with a mean followup of 35 months. Of the 70 patients 48 were alive without evidence of disease for a mean of 38 months (range 8 to 107) and 5 died without evidence of disease. Eight of these 53 patients (15%) had prostatic involvement (carcinoma in situ in 6, intraductal carcinoma in 1 and stromal invasive transitional cell carcinoma in 1). Of the 70 patients 17 had disease recurrence (13 died of disease and 4 are alive, 1 of whom had urethral recurrence without initial prostatic transitional cell carcinoma). Of the 17 patients (35%) 6 had transitional cell carcinoma prostatic involvement (carcinoma in situ in 4 and stromal invasion in 2), and 5 of these 6 died, none with or of urethral recurrence but of the primary bladder pathology. Of these 5 patients 1 had stromal invasive transitional cell carcinoma of the prostate and experienced a bulbar urethra recurrence at 1 month and a pelvic recurrence at 3 months, and died at 5 months. Death was not secondary to the urethral recurrence. Thus, of the 14 patients who had prostatic transitional cell carcinoma, only 1 had urethral recurrence (7%), and this recurrence did not present as the cause of death. CONCLUSIONS: The guidelines for urethral resection can be relaxed, increasing the opportunities for orthotopic reconstruction, without placing the patients at increased risk for death of transitional cell carcinoma.     

Surgical repair of urethral circumcision injuries

PURPOSE: The 2 types of urethral injury that can occur during circumcision are urethrocutaneous fistula and urethral distortion secondary to partial glans amputation. We report the surgical repair of these rare injuries. MATERIALS AND METHODS: In 8 patients urethrocutaneous fistulas located on the distal penile shaft or at the coronal margin were managed by splitting the glans and using a Mathieu style skin flap in 4 or vascularized penile skin flap in 4 to bridge the urethral defect. Three patients underwent repair of a hypospadiac deviated urethra secondary to partial glans amputation by 1 cm. of urethral mobilization and repositioning the meatus into a terminal position within the remaining glans tissue. RESULTS: The 8 patients with urethrocutaneous fistulas voided via a terminal meatus without fistula recurrence at a mean followup of 3.2 years (range 1 to 6). The 3 patients with partial glans amputation and urethral deviation repaired by short urethral advancement had functionally acceptable results, defined as a normal urinary stream, although 1 required meatal dilation postoperatively. CONCLUSIONS: The 2 types of urethral injuries that can occur during circumcision are a subcoronal urethrocutaneous fistula and scarred abnormal urethra from partial glans amputation. The urethrocutaneous fistula can be successfully repaired by splitting the glans and forming a neourethra from a vascularized pedicle flap of penile skin. The abnormal urethra after partial glans amputation is more difficult to repair but repositioning the urethra in a more cosmetic location has restored function.     

Experience with the hemi-Kock ileocystoplasty with a continent abdominal stoma

We describe our experience with the hemi-Kock ileocystoplasty with a continent abdominal stoma as an alternative to an indwelling catheter or supravesical diversion in 14 women and 4 men with various problems who could not perform intermittent urethral self-catheterization. The aim of management was also to provide, if possible, a competent urethra for additional access. Mean patient age was 37 years (range 22 to 75) and mean followup was 26 months (range 5 to 58). Preoperative management in the 11 wheelchair dependent women with neurological disease was an indwelling catheter in 7, urethral intermittent catheterization with the patient in the supine position in 3 and diapers in 1. Two women with a nonneurogenic bladder and a grossly incompetent urethra (1 after multiple incontinence and fistula repairs, and 1 after severe obstetrical trauma) wore diapers, while 1 with urinary retention and inability to perform self-catheterization had an indwelling catheter. The 4 men included 2 wheelchair dependent incontinent spinal cord injury patients who could not be managed with condom drainage, 1 with multiple anomalies who had trouble with self-catheterization, and 1 with an impassable postoperative stricture and a suprapubic tube. Surgery included anti-incontinence procedures in 10 patients and bladder neck closure in 3. A total of 15 patients required bladder augmentation in addition to the stoma and 3 had a stoma alone. Postoperative intervention was necessary in 4 women for stomal incontinence and in 2 of these bladder stones were removed simultaneously. One of these women was later treated for recurrent stones cystoscopically through the stoma. Overall, 17 of 18 patients are dry on intermittent stomal catheterization, with 1 lost to followup. We conclude that this procedure is a good alternative in patients with an end stage urethra or who cannot perform urethral catheterization because of physical disability. Establishing urethral continence and maintaining patency leaves a safety valve should the stoma fail. Since the bladder remains as a reservoir no ureteral surgery is necessary.     

Anatomical anterior exenteration with urethral and vaginal preservation: illustrated surgical method

PURPOSE: We describe in detail a method for urethral and vaginal preservation in women considering orthotopic urinary tract reconstruction after bladder removal. MATERIALS AND METHODS: We retrospectively reviewed the pathological reports of patients treated with anterior exenteration at our hospital between 1984 and 1997 for specific evidence of urethral, vaginal, cervical or uterine involvement by the primary bladder tumor. Based on our findings we describe our approach to anterior exenteration in 6 patients. RESULTS: A total of 46 patients were treated at our center with en bloc anterior exenteration and pelvic lymphadenectomy for primary bladder cancer between 1984 and 1997. In 7 patients (15%) pathological review of the surgical specimen documented urethral involvement by the primary tumor. In 1 patient (2%) microscopic evidence of tumor was identified in the cervix and 1 (2%) had tumor extension to the vagina documented in the final pathology report. CONCLUSIONS: The observed rates of vaginal and urethral involvement agree with those reported by others, and suggest that in the majority of women treated with anterior exenteration sacrifice of the urethra and vagina is usually not necessary from an oncological perspective. This procedure is particularly appropriate in women concerned with postoperative sexual function and those considering orthotopic reconstruction of the lower urinary tract after exenterative bladder cancer surgery.     

Urethral duplication in children: surgical treatment and results

PURPOSE: Urethral duplication is a rare congenital anomaly. We report the clinical presentation, imaging findings and surgical treatment in 7 boys with incomplete sagittal duplication of the urethra. MATERIALS AND METHODS: Duplication involved hypospadias in 5 cases (group 1) and a bifid urethra with an accessory preanal tract (Y duplication) in 2 (group 2). Group 1 was treated with 1-stage urethroplasty, including marsupialization of the dorsal orthotopic urethra, ventral-to-dorsal urethrourethrostomy and penile island flap onlay repair to cover the open dorsal urethra. In contrast, group 2 was treated with 2-stage urethral reconstruction with detachment and mobilization of the accessory preanal branch in association with a scrotal tubed neourethra followed by urethroplasty, as in group 1. In all cases the dorsal penile urethra was located between the corpora cavernosa and surrounded by the tunica albuginea. RESULTS: A urethrocutaneous fistula developed in 1 of the 5 group 1 patients. In group 2, 1 patient had recurrent penoscrotal meatal stenosis after the 1-stage procedure and 1 had a urethral diverticulum with calculi at the scrotal tubed neourethra 7 years after urethral reconstruction. Six of the 7 patients now void spontaneously through a meatus located normally at the tip of the glans. The remaining patient with a neurogenic bladder is on intermittent catheterization via appendicovesicostomy due to difficult catheterization of the irregular and sensitive neourethra. CONCLUSIONS: While the ideal surgical management of urethral duplication anomalies remains uncertain, we used a combination of surgical techniques to correct this severe malformation.     

Arguments against the involvement of Borrelia burgdorferi sensu lato in Alzheimer''s disease

The posterior prostatomembranous urethral stricture or distraction defect has historically been the most formidable challenge of stricture surgery. This uncommon lesion occurs most often as the sequelae of pelvic fracture injuries, or straddle trauma, and is associated with serious urethral disruption and separation--an injury that is often complicated by inappropriate initial management using substitution skin flap techniques with the development of recurrent stenosis, irreversible impotence, and occasional incontinence. Management by endoscopic techniques may be possible in patients with short strictures or in those after prostatectomy, but they rarely play a role in resolving the complex obliterated urethra with a significant defect [1]. Resolution of post-traumatic posterior urethral distraction defects and other posterior urethral pathologic conditions has dramatically improved over the past two decades despite an inaccessible subpublic location involving exposed sphincter-active and erectile neurovascular anatomy. The contemporary, perineal, one-stage bulboprostatic anastomotic operation as popularized by Turner-Warwick [20] with selective scar excision is a versatile procedure with a high patent lumen success. Patients undergoing anastomotic urethroplasty have a substained patent urethral lumen success rate approaching 100% versus those who have undergone urethral skin flap or patch repair, where the restricture rate in 5 and 10 years increases twofold to threefold [1, 20]. A patent urethra after an anastomotic urethroplasty at 6 months is free from further recurrent stricture and gives credence to Mr. Turner-Warwick's admonition that "urethra is the best substitute for urethra".     

One-stage anterior urethroplasty

PURPOSE: A deficient urethral segment was replaced with penile skin during a 1-stage procedure in patients with a long, tight urethral stricture, multiple attempts at hypospadias repair or severe hypospadias and circumcision. MATERIALS AND METHODS: In 29 patients a pedicled circumferential strip of distal penile skin was used to construct a neourethral floor. The roof was formed by regeneration of the epithelium from the edges of the floor over Buck's fascia. In our series the urethra was reconstructed because of an anterior urethral stricture in 11 patients, multiple failed hypospadias repairs in 6 and severe hypospadias with circumcision in 12. RESULTS: A neourethra of sufficient caliber and length was constructed with minimal postoperative complications in all patients. There were 2 cases of urethrocutaneous fistula at the subcoronal region, 1 meatal stenosis, 1 persistent chordee and 1 small distal penile skin patch slough that required only prolonged dressings. Mean followup was 19 months. CONCLUSIONS: Our urethroplasty technique can be used to correct various types of anterior urethral stricture or hypospadias associated with insufficient penile or preputial skin.     

Report of a case of traumatic avulsion of the penile skin with amputation of the glans

OBJECTIVES: A case of traumatic avulsion of penile skin with amputation of the penis and sectioning of the urethra is described. METHODS/RESULTS: Surgical management included embedding the penis without scrotal skin and subsequent reconstruction utilizing scrotal skin. The patient has recovered sexual activity, although sensitivity has been reduced as a consequence of penile amputation. Six months postoperatively, the patient has reported orgasm during intercourse. CONCLUSIONS: The surgical technique of embedding the penis is safe and preserves elasticity for subsequent reconstruction of the urethral meatus.     

Endoscopic repair in 154 cases of urethral occlusion: the promise of guided optical urethral reconstruction

PURPOSE: We determined whether optical urethral reconstruction, with the use of a Béniqué bougie in the proximal urethra and transrectal digital guidance, is effective for the treatment of long and severe urethral occlusions. However, with some skill the procedure can be done without the bougie for the treatment of short occlusions. MATERIALS AND METHODS: During a 9-year period 154 men with complete urethral occlusion underwent core through optical urethrotomy via transrectal digital guidance, using the Béniqué bougie in 89 (58%). A total of 400 urethrotomies was performed. All lesions were in the posterior urethra except 8 in the pendulous portion. There were 64 war related injuries (41.6%). Combined voiding and retrograde urethrography was not useful to measure the length of the occlusion due to failure of proximal urethral filling. Guided optical urethral reconstruction consisted of optical urethrotomy performed with a Béniqué bougie introduced proximally through the suprapubic catheter site and into the proximal urethra with the index finger of the operator in the rectum. The same procedure was performed blindly without use of the bougie in 65 patients (42%), and in 43 with lesions shorter than 1 cm. and 4 with multiple annular lesions. We also used the blind technique successfully to reestablish 18 occlusions longer than 1 cm. For optimal epithelialization of the urethral tract we suggest leaving a silicone catheter indwelling for 3 months. No prophylactic antibiotics were given. RESULTS: Of the patients 54 (35%) were cured after 1 procedure, whereas the remaining 100 (65%) required 1 to 9 additional urethrotomies (mean 3). Patients with an uninstrumented urethra who were treated initially with suprapubic catheterization required 1 to 6 urethrotomies (mean 2), compared to 1 to 10 (mean 3) for those who had undergone a prior procedure. Hematuria occurred in 9% of the patients, symptomatic urinary tract infection in 7% and slight extravasation in 3.2%. One patient had stress incontinence. CONCLUSIONS: Our procedure is effective, simple, safe, repeatable, inexpensive and minimally invasive, and it does not require special or sophisticated guiding instruments, which are necessary for previously described techniques. It can be performed with or without use of a Béniqué bougie depending on the extent of the lesion and skill of the surgeon. The outcome can be judged from the symptomatic response of the patient, and flow studies and urethrography are not mandatory during routine followup.     

Obliterative vesicourethral strictures following radical prostatectomy for prostate cancer: reconstructive armamentarium

PURPOSE: We report the reconstructive techniques used to correct obliterative vesicourethral strictures related to prostate cancer surgery. MATERIALS AND METHODS: Four men with anastomotic obliteration after radical prostatectomy underwent primary excision with end-to-end anastomosis, penile fasciocutaneous flap, free-graft urethroplasty with rectus muscle flap or anterior bladder tube with omental pedicle flap procedure. RESULTS: At mean followup of 33.8 months all patients had urethral patency but none was continent. CONCLUSIONS: Single stage reconstruction of the obliterated vesicourethral anastomosis after prostatectomy successfully restored urethral patency. No technique was applicable in all cases. Sphincteric function is likely to be compromised after the primary procedure, resulting in incontinence after successful urethral reconstruction. Subsequent artificial sphincter placement appears to be safe and helpful in restoring continence.     

Subcycling-PCR for multiplex long-distance amplification of regions with high and low GC content: application to the inversion hotspot in the factor VIII gene

OBJECTIVE: Treatment of long or multiple anterior urethral stricture(s) when Monseur technique is not applicable. Our technique entails augmentation of the dorsally slit open stenosed urethra using pedicled non-hair bearing penile skin. PATIENTS AND METHODS: Between June 1991 and May 1996, 26 men (median age 34 years) with anterior urethral strictures underwent roofing urethroplasty. Nine patients had long stricture (average 3.2 cm) and 17 had multiple short segment strictures (average 7 cm). All patients were circumcised, and dorsal urethral augmentation was performed using transversely oriented non-hair bearing penile skin pedicled flap. RESULTS: Median follow-up was 38 months (range 3-50). A successful outcome with no recurrent stricture as evidenced by normal retrograde urethrography and voiding history was achieved in 23 of 26 men (88%). Two patients had fistula in early postoperative period; one of them needed surgical closure. CONCLUSION: Roofing urethroplasty is a practical alternative for repair of long anterior urethral stricture(s) when Monseur technique cannot be applied.     

Blood pressure, renin activity and heart rate changes during propranolol therapy of hypertension

Seven boys with fracture(s) of the bony pelvis and associated partial or complete rupture of the posterior urethra were managed by the time-honored technique of early suprapubic cystostomy and concomitant primary realignment of the urethra over a catheter. Of the 4 children who had a functionally significant urethral stricture 3 were cured within a few months by 1 or 2 simple urethral dilatations and 1 by subsequent transperineal lysis of the angulated urethra from its surrounding fibrous tissue. Followup data for 8 to 22 years (mean 14 years) indicate that all 7 patients void with an excellent stream and are continent, free of infection and potent. In fact, 3 of the 4 married boys have fathered children.     

Diverticula of the female urethra

OBJECTIVES: The contribution of ultrasonography to pretreatment morphological assessment of strictures of the anterior urethra and assessment of the risk of recurrence after internal urethrotomy. MATERIAL AND METHODS: 33 patients (16-89 years) operated by internal urethrotomy for stricture of the anterior urethra and followed for at least 6 months. Preoperative urethral ultrasonography, recording the number, length and degree of strictures and echostructure of the peristenotic fibrosis of the corpus spongiosium. RESULTS: Ultrasound visualization of all urethral strictures, with no false-positives and no false-negatives. 11 patients relapsed after a mean interval of 5.7 months (1-16 months), 22 patients did not present recurrence: mean interval: 15.5 months (6-36 months). Corpus spongiosum fibrosis associated with urethral stricture is isoechoic to the corpus spongiosum (19 cases) or hyperechoic to the corpus spongiosum (14 cases). No statistical correlation was observed between the echostructure of the fibrous tissue and the risk of recurrence after internal urethrotomy. CONCLUSION: Ultrasonography allows excellent analysis of the morphological characteristics of a stricture of the male anterior urethra. In our experience, and in contrast with the limited data of the literature, no correlation was observed between the echostructure of the peristenotic fibrosis and the risk of recurrence after internal urethrotomy.     

Combined-modality therapy for squamous carcinoma of the buccal mucosa: treatment results and prognostic factors

BACKGROUND: Reports on locoregional control and survival of squamous cell carcinoma of buccal mucosa are scarce in literature. In this study, a single institutions's experience of combined surgery and postoperative radiotherapy (RT) for buccal mucosal malignancy with favorable results was analyzed and presented. The prognostic factors on locoregional control were also discussed. METHODS: From January 1988 to July 1994, 57 patients with squamous cell carcinoma of buccal mucosa treated by surgery and RT were reviewed. The distributions according to American Joint Committee on Cancer (AJCC) staging were: stage II, 6; stage III, 21; and stage IV, 30 patients. Total dose of RT at the buccal area ranged from 45 Gy to 68.4 Gy, median 61.2 Gy. Tumor-related factors (AJCC stage, T stage, histologic grading, pathologic tumor invasion to skin of cheek, adjacent bony structures, and regional lymph nodes) and treatment-related factors (surgical margin, radiation dose, and the time interval between operation and RT) were analyzed to determine their influence on locoregional control. RESULTS: Three-year actuarial locoregional control rate, overall survival rate, and disease-specific survival rates were 64%, 55%, and 62%, respectively. Ten of these 22 patients (45%) with recurrent tumors were reoperated, but only 2 patients were successfully salvaged. Positive surgical margin and tumor invasion to skin of cheek were significantly poor prognostic factors on locoregional control by univariate analysis. In multivariate analysis, tumor invasion to skin of cheek was the only prognostic factor (p = .0014). CONCLUSIONS: Locoregional failure was the major cause of death for squamous buccal mucosa cancers managed with surgery and RT. Few recurrences could be detected early and successfully salvaged. Skin of cheek involvement is an important prognostic factor for buccal mucosa cancers.     

Urethral reconstruction by pedicled labial flap in the treatment of extensive urethral lesions after obstetrical injury. Apropos of 34 cases

Reported here is our experience with a new procedure using a pedicled labial flap for urethral reconstruction in patients treated for extensive urethral damage after obstetrical injury. From January 1992 to January 1996, 31 cases of urethral damage in African female patients, with an average age of 18-years-old were treated by pedicled labial urethroplasty. This procedure was done by using a pedicled flap obtained from the major labia. The flap was then introduced as in a tunnel beneath the vaginal epithelium reaching the damaged urethra. A variety of techniques were used: the patch to lengthen sufficiency (13 cases), or the tubularized flap following complete reconstruction of the urethra (21 cases). Good quality urine continence was obtained by using the suburethral Martius' sling procedure. In 6 cases, we combined the treatment with a colposuspension procedure. The average follow-up is 14 months (ranging from 6 to 37 months). Recovery of normal micturition with absence of urinary leak was obtained in 21/30 cases (70%). While 5 moderate failures occurred, 4 cases were considered complete failures. In view of the high success rate, the authors consider that the one-stage procedure by the use of a pedicled labial flap is a choice treatment and highly suitable procedure for the management of extensive urethral cervical damage after obstetrical injury.     

The ocular blood flow tonograph: a new instrument for the measurement of intraocular pressure in rabbits

OBJECTIVES: To determine the intraprostatic pathologic changes following accurately measured doses of transurethral microwave thermal energy in patients with benign prostatic hyperplasia. METHODS: Eight patients scheduled for prostate surgery were treated for approximately 1 hour without anesthesia using a newly designed microwave treatment catheter that allows a close impedance match to prostate tissue and concentrates thermal energy preferentially in the anterior and lateral prostate gland. Interstitial, urethral, and rectal temperatures were continuously measured using a novel stereotactic thermal mapping technique. Serial sections of prostate tissue harvested during subsequent surgery were evaluated pathologically with prostate mapping. RESULTS: Microwave treatment resulted in marked and continuous intraprostate temperature elevation, while urethral and rectal temperatures remained low. Peak intraprostate temperatures in individual patients reached as high as 80 degrees C. Mean temperature reached a maximum of 54 degrees C at a radial distance of approximately 0.5 cm from the urethra and remained 45 degrees C or higher up to a distance of 1.6 cm. The predominant pathologic findings were uniform hemorrhagic necrosis and tissue devitalization without significant inflammation. The mean distance from the urethra to the viable-necrotic tissue border was 1.6 +/- 0.2 cm (range, 0.5 to 2.5). At this border, no more than 1 mm in thickness, temperature averaged 45.7 +/- 0.6 degrees C, and there was a suggestion that pure stromal nodules were more resistant to thermal injury. CONCLUSIONS: Microwave treatment can destroy obstructive prostate tissue while maintaining innocuous urethral and rectal temperatures. Temperatures of 45 degrees C or higher for approximately 1 hour cause uniform thermoablation of prostate tissue.     

Diagnosis and surgical treatment of distal urethral stenosis caused by fibrous periurethritis in women. Our experience

OBJECTIVE: To report on our experience in the diagnosis and surgical treatment of distal urethral stenosis arising from fibrous periurethritis in women. METHODS: 9 patients who had undergone surgery for distal urethral stenosis caused by fibrous periurethritis are described. Patient history, clinical symptoms, the surgical technique employed, complications and post-operative course are presented. RESULTS: All 9 patients had a history of recurrent urinary infection and alteration of the urinary stream. The results obtained by surgery were satisfactory in all cases. CONCLUSIONS: Distal urethral stenosis arising from fibrous periurethritis is uncommon, but not rare. Diagnosis is principally based on the clinical symptoms, characterized by low urinary obstructive symptoms, and the finding at physical examination of a narrow meatus and periurethral enlargement caused by fibrous tissue surrounding the distal urethra. The Richardson urethrolysis technique achieved satisfactory results in these patients.     

Aiding reduction of smoking with nicotine replacement medications: hope for the recalcitrant smoker?

A 28-year-old female had a severe depressed deformity of the left cheek due to false local injection of ZnCl2 into her buccal mucosa instead of an anesthetic. After several attempts at plastic surgery in another hospital with unsatisfactory results, she was treated surgically in our clinic using cheek skin expanded by a tissue expander. The outcome was satisfactory.     

Magnetic resonance imaging anatomy of the female urethra: a direct histologic comparison

OBJECTIVE: To define the urethral structures visible on magnetic resonance imaging (MRI) relevant to stress urinary incontinence. METHODS: The urethra and surrounding tissues were harvested from 13 female cadavers (ages 21-81) and fixed in 10% buffered formalin. High-resolution T1- and T2-weighted images were obtained at 1.5 tesla. Mallory trichrome-stained histologic sections were prepared in corresponding planes from the cadaveric specimens. Immunohistologic stains for smooth muscle (actin) and vascular endothelium (CD-34 and factor VIII) were obtained on two specimens. Histology and MRI were compared using side-by-side correlation of projected images and by superimposing projected images. Comparison was also made to a non-cadaveric urethral MRI of a 29-year-old woman and to the MRI of another specimen imaged pre- and post-fixation. RESULTS: Distinct layers of the cadaveric urethra were seen best on proton density and T2-weighted images. From the center to the periphery, a series of concentric rings were visible: an inner bright ring, the mucosa; a dark ring, the submucosa; an outer bright ring, the smooth muscle of the urethra in a loose connective tissue matrix; and a peripheral dark ring, the striated urogenital sphincter muscle of the urethra in dense connective tissue. No significant alterations were caused by fixation. These cadaveric images matched the non-cadaveric MRI of the 29-year-old woman. CONCLUSION: The internal urethral anatomy visible on high-resolution MRI can be identified and confirmed histologically, and these findings may form the basis for future anatomic investigation of stress urinary incontinence and other urethral abnormalities.