eMedicine Specialties > Urology > Benign Prostatic Hypertrophy
Transurethral Needle Ablation of the Prostate (TUNA)
Updated: Feb 7, 2008
Introduction
Transurethral needle ablation (TUNA) of the prostate is a procedure used to treat benign prostatic hypertrophy (BPH). It is performed by placing interstitial radiofrequency (RF) needles through the urethra and into the lateral lobes of the prostate, causing heat-induced coagulation necrosis. The tissue is heated to 110°C at an RF power of 456 kHz for approximately 3 minutes per lesion. A coagulation defect is created.
History of the Procedure
Transurethral resection of the prostate (TURP) was originally developed in the United States between 1920 and 1930 and was generally considered the criterion standard for surgical management of BPH.
Recent advances in the surgical treatment of BPH have come via new applications of traditional electrosurgical current. TUNA is one of these new minimally invasive treatments of prostatism. It began as a treatment in the early 1990s, with the first preliminary trials on humans in 1993. The first studies in the United States began in 1994, and the US Food and Drug Administration approved TUNA of the prostate in 1996.
Problem
BPH is a pathologic definition characterized by a cellular proliferation of stromal and epithelial components. The clinical symptoms of BPH are most likely due to the combination of a mass-related increase in urethral resistance and an obstruction-induced and age-induced detrusor dysfunction. Treatment ranges from numerous medical to surgical options. Development and growth of minimally invasive options for BPH have arisen, in part, as a response to the general public's desire for outpatient, less-invasive surgical treatment.
Prostatism describes a clinical syndrome defined as prostatic enlargement, histologic hyperplasia with lower urinary tract symptoms, diminished uroflow, or urodynamic obstruction.
Frequency
No single definition of BPH has gained universal acceptance. Histology, prostate size, symptoms of prostatism, urodynamic measurements, and performance of a prostatectomy are used to define BPH.
Histologically, BPH is characterized by an increased number of epithelial and stromal cells in the periurethral area of the prostate. Prostate size has been used in the past to define BPH, although the relationship between size and lower urinary tract symptoms has not been proven to be linear. Although likely too simplistic, the clinical symptoms of BPH, or prostatism, have been used to define BPH. Urodynamic measurements that show elevated voiding pressures and decreased urine flow also have been used to define BPH. In the past, BPH has also been viewed as an indication for surgery. Although the exact definition is unclear, surgery is indicated based on symptoms, or sequelae of BPH, such as bladder stones or renal insufficiency.
Clinical definitions often include the American Urologic Association (AUA) Symptom Score and the International Prostate Symptom Score (IPSS), which are 2 indices that attempt to define BPH based on its symptoms.
The following table is the AUA Symptom Score. Patient responses to the questions in the table are assigned point values, as follows:
- Not at all = 0 points
- Fewer than 1 in 5 = 1 point
- Less than half the time = 2 points
- Approximately half the time = 3 points
- More than half the time = 4 points
- Almost always = 5 points
Open table in new window
Table
| Over the past month: | Value based on above criteria |
|---|---|
| How often have you had a sensation of not emptying your bladder completely after you finished urinating? | |
| How often have you had to urinate again less than 2 hours after you finished urinating? | |
| How often have you stopped and started again several times when you urinated? | |
| How often have you found it difficult to postpone urination? | |
| How often have you had a weak urinary stream? | |
| How often have you had to push or strain to begin urination? | |
| Over the last month, how many times did you most typically get up to urinate from the time you went to bed at night until the time you get up in the morning? | 0 = None 1 = 1 time 2 = 2 times 3 = 3 times 4 = 4 times 5 = 5 or more times |
| Over the past month: | Value based on above criteria |
|---|---|
| How often have you had a sensation of not emptying your bladder completely after you finished urinating? | |
| How often have you had to urinate again less than 2 hours after you finished urinating? | |
| How often have you stopped and started again several times when you urinated? | |
| How often have you found it difficult to postpone urination? | |
| How often have you had a weak urinary stream? | |
| How often have you had to push or strain to begin urination? | |
| Over the last month, how many times did you most typically get up to urinate from the time you went to bed at night until the time you get up in the morning? | 0 = None 1 = 1 time 2 = 2 times 3 = 3 times 4 = 4 times 5 = 5 or more times |
After totaling the scores from the table, the symptoms are assigned the following classifications:
- 0-7 points – Mild
- 8-19 points – Moderate
- 20-35 points – Severe
The IPSS is essentially the same as the AUA Symptom Score.
Using autopsy data, histopathologic evidence of BPH occurs in less than 10% of men aged 40-50 years, 50% of men aged 51-60 years, and 90% of men older than 80 years.
With a clinical diagnosis based on history and a physical examination, the Baltimore Longitudinal Study of Aging diagnosed 69% of men aged 61-70 years with BPH. The Baltimore Longitudinal Study of Aging is a long-term prospective study of normal human aging. It is a National Institute of Health study that was established in 1958 and originally enrolled 1371 men. The subjects are examined every 2 years. Many diagnoses are studied, including BPH. BPH in this study is diagnosed based on clinical judgment, taking into account medical history and digital rectal examination findings.
Regardless of the definition, BPH is an extremely common condition.
Etiology
BPH is characterized by an increased number of epithelial and stromal cells in the periurethral area of the prostate. The increased number of cells is most likely due to epithelial and stromal proliferation or impaired programmed cell death. Other factors may play a role, such as androgens, estrogens, stromal-epithelial interactions, growth factors, and neurotransmitters.
Pathophysiology
Prostatic enlargement leads to an increase in urethral resistance, which then results in secondary bladder changes. Obstruction-related changes in the detrusor function are most likely compounded by age-related changes in bladder and nervous system function. These changes lead to the BPH-related conditions of frequency, urgency, hesitancy, nocturia, and other symptoms.
The TUNA system produces thermal tissue ablation by applying low-level RF energy to prostate tissue. The generated RF is in the form of electrical energy and is delivered by the 2 electrodes, which are in contact with the patient. As the prostate cells resist passage of the current, thermal energy is produced by friction and by the heating of water molecules. This leads to tissue heating and, ultimately, coagulation necrosis. Thermal lesions occur only in a localized area because the RF signal is transmitted into tissue only by direct contact.
Presentation
Patients typically present with worsening symptoms from BPH that begin to affect their quality of life, which are the same symptoms used in the IPSS.
Perform a thorough history and physical examination. The examination should be performed to evaluate for other causes of voiding dysfunction. Multiple aspects of the physical examination might suggest another cause of voiding dysfunction. A general neurologic examination should be performed to assess neurologic function and mental status, motor function, sensory function, and reflexes. Myriad findings may suggest etiologies of dysfunction, from cerebrovascular accident to multiple sclerosis to diabetes mellitus.
Other causes of voiding problems should also be sought in the history and physical examination. For instance, one should evaluate for meatal stenosis or palpable urethral masses. The rectal examination is important to evaluate for prostate nodules or rectal cancers. For patients who require invasive therapy, the digital rectal examination can estimate the size of the prostate. The size of the prostate is important in determining the most appropriate technical approach. However, importantly, note that the size of the prostate does not correlate with the degree of symptoms. Size has not been found to correlate with symptom severity or degree of obstruction after urodynamic evaluation.
Conduct a urinalysis to rule out a urinary tract infection.
Evaluate an obstructive uropathy, if suspected, with a serum creatinine study. It fact, a routine creatine measurement is probably reasonable because distinguishing patients who have obstructive uropathy from patients who do not is difficult. In the authors' practice, a referring physician makes the initial diagnosis in most patients who have renal insufficiency.
Patients with advanced BPH may present with bladder stones or urinary retention.
Conduct uroflowmetry, postvoid residual urine tests, and pressure-flow studies to further evaluate for the possible presence of BPH. These studies are considered optional based on the AUA guidelines for evaluating BPH.
Upper-tract imaging is typically not indicated.
Urethrocystoscopy may be indicated to help select the optimal form of therapy.
Indications
Deciding which intervention to choose is difficult. TURP is still considered the criterion standard for surgical intervention. The newer less-invasive treatments are still being evaluated. In general, these treatments are considered less morbid; however, the results are not considered as efficacious or long lasting as the formal TURP. Transurethral needle ablation (TUNA) is offered as one of the less-invasive surgical treatment modalities.
Minimally invasive therapy is generally the next step after failed medical management. This therapy is also the primary therapy for a patient who is not interested in medical therapy and unwilling to undergo a TURP.
Symptoms constitute the primary reason to recommend surgical intervention. This is especially true in light of objective evidence of abnormal function, such as the patient with urodynamic evidence of low peak flow and high residual urine volumes. However, some more absolute indications exist. These are generally considered to be urinary retention, recurrent infection, bladder stones, and azotemia.
Contraindications
No absolute contraindications exist to performing a transurethral needle ablation (TUNA) of the prostate. The relative contraindications are a high bladder neck and large prostate. A large median lobe used to be a contraindication for the procedure, but TUNA is now approved for the treatment of median lobes. In fact, TUNA offers several advantages compared to TURP, as follows:
- TUNA can be performed in an outpatient or clinic setting with local anesthesia (block of periprostatic nerves) and oral sedation (diazepam [Valium]). Patients are also given a dose of oral meperidine (Demerol) prior to the procedure.
- The cost is less in terms of the direct cost of the procedure and recovery time, both in and out of the hospital. Naslund and Stitcher estimate that TUNA is 40-50% less expensive than TURP.1 Chapple et al have described other specifics.2 The initial cost of the generator and computer is approximately $16,500. The cost of the disposables range from $1050-$1400 (depending on the volume of cartridges that are ordered). The current global fee is approximately $3500. Of course, those who need further operations also incur those additional costs.
- A recent cost analysis compared medical therapy with TUNA and found that a 5-year regimen of 5-alpha reductase inhibitor therapy cost the same as TUNA.3 A 5-year regimen of tamsulosin therapy was slightly less expensive. However, combination therapy was found to be more expensive, reaching an equivalent cost to TUNA at 2 years and 7 months.
- The intraoperative and postoperative morbidity and mortality rates associated with TURP are significantly higher than with TUNA. TUNA is associated with fewer sexual side effects and less bleeding. The anesthetic requirement is also lower. Although more recent data suggest that the long-term outcomes may not be as durable as those achieved with TURP, the decreased associated morbidity makes TUNA a useful treatment option for prostatism in select patients.
More on Transurethral Needle Ablation of the Prostate (TUNA) |
 Overview: Transurethral Needle Ablation of the Prostate (TUNA) |
| Workup: Transurethral Needle Ablation of the Prostate (TUNA) |
| Treatment: Transurethral Needle Ablation of the Prostate (TUNA) |
| Follow-up: Transurethral Needle Ablation of the Prostate (TUNA) |
| References |
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References
Naslund MJ, Stitcher MF. A cost comparison of TUNA vs TURP. J Urol. 1997;157 (supplement):155A.
Chapple CR, Issa MM, Woo H. Transurethral needle ablation (TUNA). A critical review of radiofrequency thermal therapy in the management of benign prostatic hyperplasia. Eur Urol. Feb 1999;35(2):119-28. [Medline].
Naslund MJ, Carlson AM, Williams MJ. A cost comparison of medical management and transurethral needle ablation for treatment of benign prostatic hyperplasia during a 5-year period. J Urol. Jun 2005;173(6):2090-3; discussion 2093. [Medline].
Rosario DJ, Woo H, Potts KL, Cutinha PE, Hastie KJ, Chapple CR. Safety and efficacy of transurethral needle ablation of the prostate for symptomatic outlet obstruction. Br J Urol. Oct 1997;80(4):579-86. [Medline].
Kahn SA, Alphonse P, Tewari A, Narayan P. An open study on the efficacy and safety of transurethral needle ablation of the prostate in treating symptomatic benign prostatic hyperplasia: the University of Florida experience. J Urol. Nov 1998;160(5):1695-700. [Medline].
Rodrígo Aliaga M, López Alcina E, Monserrat Monfort JJ, Pontones Moreno JL, Valls Blasco F, Boronat Tormo F, et al. [Treatment of benign hyperplasia of the prostate using thermal transurethral needle ablation (TUNA)]. Actas Urol Esp. Jul-Aug 1997;21(7):649-54. [Medline].
Millard RJ, Harewood LM, Tamaddon K. A study of the efficacy and safety of transurethral needle ablation (TUNA) treatment for benign prostatic hyperplasia. Neurourol Urodyn. 1996;15(6):619-28; discussion 628-9. [Medline].
Zlotta AR, Peny MO, Matos C, Schulman CC. Transurethral needle ablation of the prostate: clinical experience in patients in urinary acute retention. Br J Urol. Mar 1996;77(3):391-7. [Medline].
Schulman CC, Zlotta AR. Transurethral needle ablation of the prostate for treatment of benign prostatic hyperplasia: early clinical experience. Urology. Jan 1995;45(1):28-33. [Medline].
Hill B, Belville W, Bruskewitz R, Issa M, Perez-Marrero R, Roehrborn C, et al. Transurethral needle ablation versus transurethral resection of the prostate for the treatment of symptomatic benign prostatic hyperplasia: 5-year results of a prospective, randomized, multicenter clinical trial. J Urol. Jun 2004;171(6 Pt 1):2336-40. [Medline].
Beduschi MC, Oesterling JE. Transurethral needle ablation of the prostate: a minimally invasive treatment for symptomatic benign prostatic hyperplasia. Mayo Clin Proc. Jul 1998;73(7):696-701. [Medline].
Berry SJ, Coffey DS, Walsh PC, Ewing LL. The development of human benign prostatic hyperplasia with age. J Urol. Sep 1984;132(3):474-9. [Medline].
Bouza C, Lopez T, Magro A, Navalpotro L, Amate JM. Systematic review and meta-analysis of Transurethral Needle Ablation in symptomatic Benign Prostatic Hyperplasia. BMC Urol. 2006;6:14. [Medline].
Boyle P, Robertson C, Vaughan ED, Fitzpatrick JM. A meta-analysis of trials of transurethral needle ablation for treating symptomatic benign prostatic hyperplasia. BJU Int. Jul 2004;94(1):83-8. [Medline].
Bruskewitz R, Issa MM, Roehrborn CG, Naslund MJ, Perez-Marrero R, Shumaker BP, et al. A prospective, randomized 1-year clinical trial comparing transurethral needle ablation to transurethral resection of the prostate for the treatment of symptomatic benign prostatic hyperplasia. J Urol. May 1998;159(5):1588-93; discussion 1593-4. [Medline].
Guess HA, Arrighi HM, Metter EJ, Fozard JL. Cumulative prevalence of prostatism matches the autopsy prevalence of benign prostatic hyperplasia. Prostate. 1990;17(3):241-6. [Medline].
Lepor H. Natural History, Evaluation, and Nonsurgical Management of Benign Prostatic Hyperplasia. In: Walsh PC,Retik AB, Vaughan ED Jr, Wein AJ. Campbell's Urology. 7th ed. Philadelphia, Pa: WB Saunders; 1998:1453-60.
McConnell JD. Epidemiology, Etiology, Pathophysiology, and Diagnosis of Benign Prostatic Hyperplasia. In: Walsh PC, Retik AB, Vaughan ED Jr, Wein AJ. Campbell's Urology. 7th ed. Philadelphia, Pa: WB Saunders; 1998:1429-52.
McCullogh DL. Minimally Invasive Treatment of Benign Prostatic Hyperplasia. In: Walsh PC, Retik AB, Vaughan ED Jr, Wein AJ. Campbell's Urology. 7th ed. Philadelphia, Pa: WB Saunders; 1998:1503-5.
Mebust WK. Transurethral Surgery. In: Walsh PC, Retik AB, Vaughan ED Jr, Wein AJ. Campbell's Urology. 7th ed. Philadelphia, Pa: WB Saunders; 1998:1511-28.
Perlmutter AP. New Uses of Energy for the Treatment of BPH. AUA Update Series. 1997;XVI:250-5.
Roehrborn CG, Issa MM, Bruskewitz RC, Naslund MJ, Oesterling JE, Perez-Marrero R, et al. Transurethral needle ablation for benign prostatic hyperplasia: 12-month results of a prospective, multicenter U.S. study. Urology. Mar 1998;51(3):415-21. [Medline].
Schulman CC, Zlotta AR. Transurethral needle ablation (TUNA) of the prostate: clinical experience with two years follow-up in patients with benign prostatic hyperplasia (BPH). Eur Urol. 1996;30(Suppl 2):263.
Schulman CC, Zlotta AR, Rasor JS, Hourriez L, Noel JC, Edwards SD. Transurethral needle ablation (TUNA): safety, feasibility, and tolerance of a new office procedure for treatment of benign prostatic hyperplasia. Eur Urol. 1993;24(3):415-23. [Medline].
Keywords
transurethral needle ablation, transurethral needle ablation of the prostate, TUNA, transurethral destruction of prostate tissue by radiofrequency thermotherapy, TUMP, prostate cancer, prostate surgery, prostate-specific antigen, prostate specific antigen, PSA, prostate needle ablation, benign prostatic hypertrophy, benign prostatic hyperplasia, BPH, prostatism, American Urologic Association Symptom Score, AUA Symptom Score, International Prostate Symptom Score, IPSS, prostatic enlargement, enlarged prostate, digital rectal examination, DRE, interstitial radiofrequency needles, interstitial RF needles, heat-induced coagulation necrosis, transurethral resection of the prostate, TURP, TUNA of the prostate, diminished uroflow, urodynamic obstruction
