- Department of Rehabilitation Medicine, the First Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215006, P. R. China;
YANG Weixin,
Email: weixinsuda@163.com
Injection of botulinum toxin A (BTX-A) into the detrusor muscle and urethral sphincter can block the release of acetylcholine from the presynaptic efferent nerve at the neuromuscular junction, inhibit the contraction of the target muscle, improve bladder pressure and urodynamic parameters, reduce the incidence of urinary tract infection and improve quality of life. Currently, BTX-A has been approved by the Food and Drug Administration for the treatment of neurogenic detrusor overactivity and refractory overactive bladder. A recent clinical trial of BTX-A in the treatment of detrusor-sphincter coordination disorders also reported promising therapeutic effects. This article reviews the BTX-A injection therapy for neurogenic detrusor muscle overactivity and detrusor-sphincter dyssynergia induced by upper motor neuron injury, especially cerebral cortex and suprasacral spinal cord injury.
Citation： YANG Weixin. Botulinum toxin A injection for neurogenic bladder. West China Medical Journal, 2023, 38(6): 822-827. doi: 10.7507/1002-0179.202305018 Copy
| 1. | Panicker JN, Fowler CJ, Kessler TM. Lower urinary tract dysfunction in the neurological patient: clinical assessment and management. Lancet Neurol, 2015, 14(7): 720-732. |
| 2. | Panicker JN. Neurogenic bladder: epidemiology, diagnosis, and management. Semin Neurol, 2020, 40(5): 569-579. |
| 3. | Drake MJ, Apostolidis A, Cocci A, et al. Neurogenic lower urinary tract dysfunction: clinical management recommendations of the Neurologic Incontinence committee of the fifth International Consultation on Incontinence 2013. Neurourol Urodyn, 2016, 35(6): 657-665. |
| 4. | Kaviani A, Khavari R. Disease-specific outcomes of botulinum toxin injections for neurogenic detrusor overactivity. Urol Clin North Am, 2017, 44(3): 463-474. |
| 5. | Dykstra DD, Sidi AA, Scott AB, et al. Effects of botulinum A toxin on detrusor-sphincter dyssynergia in spinal cord injury patients. J Urol, 1988, 139(5): 919-922. |
| 6. | Kuo HC. Clinical application of botulinum neurotoxin in lower-urinary-tract diseases and dysfunctions: where are we now and what more can we do?. Toxins (Basel), 2022, 14(7): 498. |
| 7. | Del Popolo G, Gemma L. Intradetrusor botulinum toxin as the first-line treatment for neurogenic detrusor overactivity: Cons. Prog Urol, 2023, 33(4): 176-177. |
| 8. | Solish N, Carruthers J, Kaufman J, et al Overview of daxibotulinumtoxina for injection: a novel formulation of botulinum toxin type A. Drugs, 2021, 81(18): 2091-2101. |
| 9. | Mangera A, Andersson KE, Apostolidis A, et al. Contemporary management of lower urinary tract disease with botulinum toxin A: a systematic review of botox (onabotulinumtoxinA) and dysport (abobotulinumtoxinA). Eur Urol, 2011, 60(4): 784-795. |
| 10. | Eldred-Evans D, Dasgupta P. Use of botulinum toxin for voiding dysfunction. Transl Androl Urol, 2017, 6(2): 234-251. |
| 11. | Dong M, Yeh F, Tepp WH, et al. SV2 is the protein receptor for botulinum neurotoxin A. Science, 2006, 312(5773): 592-596. |
| 12. | Yoshimura N. Bladder afferent pathway and spinal cord injury: possible mechanisms inducing hyperreflexia of the urinary bladder. Prog Neurobiol, 1999, 57(6): 583-606. |
| 13. | Chapple C, Patel A. Botulinum toxin-new mechanisms, new therapeutic directions?. Eur Urol, 2006, 49(4): 606-608. |
| 14. | Smith CP, Franks ME, McNeil BK, et al. Effect of botulinum toxin A on the autonomic nervous system of the rat lower urinary tract. J Urol, 2003, 169(5): 1896-1900. |
| 15. | Cruz F, Herschorn S, Aliotta P, et al. Efficacy and safety of onabotulinumtoxin A in patients with urinary incontinence due to neurogenic detrusor overactivity: a randomised, double-blind, placebo-controlled trial. Eur Urol, 2011, 60(4): 742-750. |
| 16. | Ginsberg D, Gousse A, Keppenne V, et al. Phase 3 efficacy and tolerability study of onabotulinumtoxin A for urinary incontinence from neurogenic detrusor overactivity. J Urol, 2012, 187(6): 2131-2139. |
| 17. | Aalami Harandi A, Nauheim J, Abraham NE. Risk of retention after onabotulinumtoxin A injection for overactive bladder in a diverse urban population with high BMI and comorbidity rates. Urogynecology (Phila), 2023, 29(1): 41-47. |
| 18. | Bapir R, Bhatti KH, Eliwa A, et al. Efficacy of overactive neurogenic bladder treatment: a systematic review of randomized controlled trials. Arch Ital Urol Androl, 2022, 94(4): 492-506. |
| 19. | Franco I, Hoebeke PB, Dobremez E, et al. Long-term safety and tolerability of repeated treatments with onabotulinumtoxin A in children with neurogenic detrusor overactivity. J Urol, 2023, 209(4): 774-784. |
| 20. | Cooley LF, Kielb S. A review of botulinum toxin a for the treatment of neurogenic bladder. PM R, 2019, 11(2): 192-200. |
| 21. | Kuo HC. Comparison of effectiveness of detrusor, suburothelial and bladder base injections of botulinum toxin a for idiopathic detrusor overactivity. J Urol, 2007, 178(1): 1359-1363. |
| 22. | 中华医学会泌尿外科学分会尿控学组. 肉毒毒素治疗下尿路功能障碍中国专家共识. 中华泌尿外科杂志, 2021, 42(6): 405-410. |
| 23. | Coelho A, Cruz F, Cruz CD, et al. Spread of onabotulinumtoxin A after bladder injection. experimental study using the distribution of cleaved SNAP-25 as the marker of the toxin action. Eur Urol, 2012, 61(6): 1178-1184. |
| 24. | Giannantoni A, Proietti S, Costantini E, et al. Onabotulinumtoxin A intravesical treatment in patients affected by overactive bladder syndrome: best practice in real-life management. Urologia, 2015, 82(3): 179-183. |
| 25. | Apostolidis A, Dasgupta P, Denys P, et al. Recommendations on the use of botulinum toxin in the treatment of lower urinary tract disorders and pelvic floor dysfunctions: a European consensus report. Eur Urol, 2009, 55(1): 100-119. |
| 26. | Dasgupta P. Volume matters: bladder injections of botulinum toxin type A. Eur Urol, 2012, 61(6): 1185-1187. |
| 27. | Manecksha RP, Cullen IM, Ahmad S, et al. Prospective randomised controlled trial comparing trigone-sparing versus trigone-including intradetrusor injection of abobotulinumtoxinA for refractory idiopathic detrusor overactivity. Eur Urol, 2012, 61(5): 928-935. |
| 28. | Karsenty G, Baverstock R, Carlson K, et al. Technical aspects of botulinum toxin type A injection in the bladder to treat urinary incontinence: reviewing the procedure. Int J Clin Pract, 2014, 68(6): 731-742. |
| 29. | Kuo HC, Liao CH, Chung SD. Adverse events of intravesical botulinum toxin a injections for idiopathic detrusor overactivity: risk factors and influence on treatment outcome. Eur Urol, 2010, 58(6): 919-926. |
| 30. | Kuo YC, Kuo HC. Adverse events of intravesical onabotulinumtoxina injection between patients with overactive bladder and interstitial cystitis-different mechanisms of action of botox on bladder dysfunction?. Toxins (Basel), 2016, 8(3): 75. |
| 31. | Chen JL, Kuo HC. Clinical application of intravesical botulinum toxin type A for overactive bladder and interstitial cystitis. Investig Clin Urol, 2020, 61(Suppl 1): S33-S42. |
| 32. | Stoffel JT. Detrusor sphincter dyssynergia: a review of physiology, diagnosis, and treatment strategies. Transl Androl Urol, 2016, 5(1): 127-135. |
| 33. | Biardeau X, Corcos J. Intermittent catheterization in neurologic patients: update on genitourinary tract infection and urethral trauma. Ann Phys Rehabil Med, 2016, 59(2): 125-129. |
| 34. | Gallien P, Reymann JM, Amarenco G, et al. Placebo controlled, randomised, double blind study of the effects of botulinum A toxin on detrusor sphincter dyssynergia in multiple sclerosis patients. J Neurol Neurosurg Psychiatry, 2005, 76(12): 1670-1676. |
| 35. | Kao YL, Huang KH, Kuo HC, et al. The therapeutic effects and pathophysiology of botulinum toxin A on voiding dysfunction due to urethral sphincter dysfunction. Toxins (Basel), 2019, 11(12): 728. |
| 36. | de Sèze M, Petit H, Gallien P, et al. Botulinum a toxin and detrusor sphincter dyssynergia: a double-blind lidocaine-controlled study in 13 patients with spinal cord disease. Eur Urol, 2002, 42(1): 56-62. |
| 37. | 杨卫新, 苏敏, 张大伟, 等. 超声引导肉毒毒素注射尿道外括约肌治疗下尿路功能障碍. 中华物理医学与康复杂志, 2013, 35(4): 286-289. |
| 38. | Yang WX, Zhu HJ, Chen WG, et al. Treatment of detrusor external sphincter dyssynergia using ultrasound-guided trocar catheter transurethral botulinum toxin a injection in men with spinal cord injury. Arch Phys Med Rehabil, 2015, 96(4): 614-619. |
| 39. | Kuo HC. Recovery of detrusor function after urethral botulinum A toxin injection in patients with idiopathic low detrusor contractility and voiding dysfunction. Urology, 2007, 69(1): 57-61. |
| 40. | Panicker JN, Game X, Khan S, et al. The possible role of opiates in women with chronic urinary retention: observations from a prospective clinical study. J Urol, 2012, 188(2): 480-484. |
| 41. | Seth J, Rintoul-Hoad S, Sahai A. Urethral sphincter injection of botulinum toxin A: a review of its application and outcomes. Low Urin Tract Symptoms, 2018, 10(2): 109-115. |
| 42. | Huang YH, Chen SL. Concomitant detrusor and external urethral sphincter botulinum toxin-A injections in male spinal cord injury patients with detrusor overactivity and detrusor sphincter dyssynergia. J Rehabil Med, 2022, 54: jrm00264. |
| 43. | Smith CP, Nishiguchi J, O’Leary M, et al. Single-institution experience in 110 patients with botulinum toxin A injection into bladder or urethra. Urology, 2005, 65(1): 37-41. |
| 44. | Schurch B, Hauri D, Rodic B, et al. Botulinum-A toxin as a treatment of detrusor-sphincter dyssynergia: a prospective study in 24 spinal cord injury patients. J Urol, 1996, 155(3): 1023-1029. |
| 45. | Haferkamp A, Schurch B, Reitz A, et al. Lack of ultrastructural detrusor changes following endoscopic injection of botulinum toxin type a in overactive neurogenic bladder. Eur Urol, 2004, 46(6): 784-791. |
| 46. | Kuo HC. Satisfaction with urethral injection of botulinum toxin A for detrusor sphincter dyssynergia in patients with spinal cord lesion. Neurourol Urodyn, 2008, 27(8): 793-796. |
| 47. | Panicker JN, Seth JH, Khan S, et al. Open-label study evaluating outpatient urethral sphincter injections of onabotulinumtoxin A to treat women with urinary retention due to a primary disorder of sphincter relaxation (Fowler’s syndrome). BJU Int, 2016, 117(5): 809-813. |
| 48. | Kennelly M, Dmochowski R, Ethans K, et al. Long-term efficacy and safety of onabotulinumtoxin A in patients with urinary incontinence due to neurogenic detrusor overactivity: an interim analysis. Urology, 2013, 81(3): 491-497. |
| 49. | Gaillet S, Bardot P, Bernuz B, et al. Five years follow-up study and failures analysis of botulinum toxin repeated injections to treat neurogenic detrusor overactivity. Prog Urol, 2012, 22(17): 1064-1070. |
| 50. | Bellows S, Jankovic J. Immunogenicity associated with botulinum toxin treatment. Toxins (Basel), 2019, 11(9): 491. |
| 51. | Jost WH, Benecke R, Hauschke D, et al. Clinical and pharmacological properties of incobotulinumtoxin A and its use in neurological disorders. Drug Des Devel Ther, 2015, 9: 1913-1926. |
| 52. | Chuang YC, Tyagi P, Huang CC, et al. Urodynamic and immunohistochemical evaluation of intravesical botulinum toxin A delivery using liposomes. J Urol, 2009, 182(2): 786-792. |
| 53. | Kuo HC, Liu HT, Chuang YC, et al. Pilot study of liposome-encapsulated onabotulinumtoxina for patients with overactive bladder: a single-center study. Eur Urol, 2014, 65(6): 1117-1124. |
| 54. | Hung FC, Kuo HC. Liposome-encapsulated botulinum toxin A in treatment of functional bladder disorders. Toxins (Basel), 2022, 14(12): 838. |
- 1. Panicker JN, Fowler CJ, Kessler TM. Lower urinary tract dysfunction in the neurological patient: clinical assessment and management. Lancet Neurol, 2015, 14(7): 720-732.
- 2. Panicker JN. Neurogenic bladder: epidemiology, diagnosis, and management. Semin Neurol, 2020, 40(5): 569-579.
- 3. Drake MJ, Apostolidis A, Cocci A, et al. Neurogenic lower urinary tract dysfunction: clinical management recommendations of the Neurologic Incontinence committee of the fifth International Consultation on Incontinence 2013. Neurourol Urodyn, 2016, 35(6): 657-665.
- 4. Kaviani A, Khavari R. Disease-specific outcomes of botulinum toxin injections for neurogenic detrusor overactivity. Urol Clin North Am, 2017, 44(3): 463-474.
- 5. Dykstra DD, Sidi AA, Scott AB, et al. Effects of botulinum A toxin on detrusor-sphincter dyssynergia in spinal cord injury patients. J Urol, 1988, 139(5): 919-922.
- 6. Kuo HC. Clinical application of botulinum neurotoxin in lower-urinary-tract diseases and dysfunctions: where are we now and what more can we do?. Toxins (Basel), 2022, 14(7): 498.
- 7. Del Popolo G, Gemma L. Intradetrusor botulinum toxin as the first-line treatment for neurogenic detrusor overactivity: Cons. Prog Urol, 2023, 33(4): 176-177.
- 8. Solish N, Carruthers J, Kaufman J, et al Overview of daxibotulinumtoxina for injection: a novel formulation of botulinum toxin type A. Drugs, 2021, 81(18): 2091-2101.
- 9. Mangera A, Andersson KE, Apostolidis A, et al. Contemporary management of lower urinary tract disease with botulinum toxin A: a systematic review of botox (onabotulinumtoxinA) and dysport (abobotulinumtoxinA). Eur Urol, 2011, 60(4): 784-795.
- 10. Eldred-Evans D, Dasgupta P. Use of botulinum toxin for voiding dysfunction. Transl Androl Urol, 2017, 6(2): 234-251.
- 11. Dong M, Yeh F, Tepp WH, et al. SV2 is the protein receptor for botulinum neurotoxin A. Science, 2006, 312(5773): 592-596.
- 12. Yoshimura N. Bladder afferent pathway and spinal cord injury: possible mechanisms inducing hyperreflexia of the urinary bladder. Prog Neurobiol, 1999, 57(6): 583-606.
- 13. Chapple C, Patel A. Botulinum toxin-new mechanisms, new therapeutic directions?. Eur Urol, 2006, 49(4): 606-608.
- 14. Smith CP, Franks ME, McNeil BK, et al. Effect of botulinum toxin A on the autonomic nervous system of the rat lower urinary tract. J Urol, 2003, 169(5): 1896-1900.
- 15. Cruz F, Herschorn S, Aliotta P, et al. Efficacy and safety of onabotulinumtoxin A in patients with urinary incontinence due to neurogenic detrusor overactivity: a randomised, double-blind, placebo-controlled trial. Eur Urol, 2011, 60(4): 742-750.
- 16. Ginsberg D, Gousse A, Keppenne V, et al. Phase 3 efficacy and tolerability study of onabotulinumtoxin A for urinary incontinence from neurogenic detrusor overactivity. J Urol, 2012, 187(6): 2131-2139.
- 17. Aalami Harandi A, Nauheim J, Abraham NE. Risk of retention after onabotulinumtoxin A injection for overactive bladder in a diverse urban population with high BMI and comorbidity rates. Urogynecology (Phila), 2023, 29(1): 41-47.
- 18. Bapir R, Bhatti KH, Eliwa A, et al. Efficacy of overactive neurogenic bladder treatment: a systematic review of randomized controlled trials. Arch Ital Urol Androl, 2022, 94(4): 492-506.
- 19. Franco I, Hoebeke PB, Dobremez E, et al. Long-term safety and tolerability of repeated treatments with onabotulinumtoxin A in children with neurogenic detrusor overactivity. J Urol, 2023, 209(4): 774-784.
- 20. Cooley LF, Kielb S. A review of botulinum toxin a for the treatment of neurogenic bladder. PM R, 2019, 11(2): 192-200.
- 21. Kuo HC. Comparison of effectiveness of detrusor, suburothelial and bladder base injections of botulinum toxin a for idiopathic detrusor overactivity. J Urol, 2007, 178(1): 1359-1363.
- 22. 中华医学会泌尿外科学分会尿控学组. 肉毒毒素治疗下尿路功能障碍中国专家共识. 中华泌尿外科杂志, 2021, 42(6): 405-410.
- 23. Coelho A, Cruz F, Cruz CD, et al. Spread of onabotulinumtoxin A after bladder injection. experimental study using the distribution of cleaved SNAP-25 as the marker of the toxin action. Eur Urol, 2012, 61(6): 1178-1184.
- 24. Giannantoni A, Proietti S, Costantini E, et al. Onabotulinumtoxin A intravesical treatment in patients affected by overactive bladder syndrome: best practice in real-life management. Urologia, 2015, 82(3): 179-183.
- 25. Apostolidis A, Dasgupta P, Denys P, et al. Recommendations on the use of botulinum toxin in the treatment of lower urinary tract disorders and pelvic floor dysfunctions: a European consensus report. Eur Urol, 2009, 55(1): 100-119.
- 26. Dasgupta P. Volume matters: bladder injections of botulinum toxin type A. Eur Urol, 2012, 61(6): 1185-1187.
- 27. Manecksha RP, Cullen IM, Ahmad S, et al. Prospective randomised controlled trial comparing trigone-sparing versus trigone-including intradetrusor injection of abobotulinumtoxinA for refractory idiopathic detrusor overactivity. Eur Urol, 2012, 61(5): 928-935.
- 28. Karsenty G, Baverstock R, Carlson K, et al. Technical aspects of botulinum toxin type A injection in the bladder to treat urinary incontinence: reviewing the procedure. Int J Clin Pract, 2014, 68(6): 731-742.
- 29. Kuo HC, Liao CH, Chung SD. Adverse events of intravesical botulinum toxin a injections for idiopathic detrusor overactivity: risk factors and influence on treatment outcome. Eur Urol, 2010, 58(6): 919-926.
- 30. Kuo YC, Kuo HC. Adverse events of intravesical onabotulinumtoxina injection between patients with overactive bladder and interstitial cystitis-different mechanisms of action of botox on bladder dysfunction?. Toxins (Basel), 2016, 8(3): 75.
- 31. Chen JL, Kuo HC. Clinical application of intravesical botulinum toxin type A for overactive bladder and interstitial cystitis. Investig Clin Urol, 2020, 61(Suppl 1): S33-S42.
- 32. Stoffel JT. Detrusor sphincter dyssynergia: a review of physiology, diagnosis, and treatment strategies. Transl Androl Urol, 2016, 5(1): 127-135.
- 33. Biardeau X, Corcos J. Intermittent catheterization in neurologic patients: update on genitourinary tract infection and urethral trauma. Ann Phys Rehabil Med, 2016, 59(2): 125-129.
- 34. Gallien P, Reymann JM, Amarenco G, et al. Placebo controlled, randomised, double blind study of the effects of botulinum A toxin on detrusor sphincter dyssynergia in multiple sclerosis patients. J Neurol Neurosurg Psychiatry, 2005, 76(12): 1670-1676.
- 35. Kao YL, Huang KH, Kuo HC, et al. The therapeutic effects and pathophysiology of botulinum toxin A on voiding dysfunction due to urethral sphincter dysfunction. Toxins (Basel), 2019, 11(12): 728.
- 36. de Sèze M, Petit H, Gallien P, et al. Botulinum a toxin and detrusor sphincter dyssynergia: a double-blind lidocaine-controlled study in 13 patients with spinal cord disease. Eur Urol, 2002, 42(1): 56-62.
- 37. 杨卫新, 苏敏, 张大伟, 等. 超声引导肉毒毒素注射尿道外括约肌治疗下尿路功能障碍. 中华物理医学与康复杂志, 2013, 35(4): 286-289.
- 38. Yang WX, Zhu HJ, Chen WG, et al. Treatment of detrusor external sphincter dyssynergia using ultrasound-guided trocar catheter transurethral botulinum toxin a injection in men with spinal cord injury. Arch Phys Med Rehabil, 2015, 96(4): 614-619.
- 39. Kuo HC. Recovery of detrusor function after urethral botulinum A toxin injection in patients with idiopathic low detrusor contractility and voiding dysfunction. Urology, 2007, 69(1): 57-61.
- 40. Panicker JN, Game X, Khan S, et al. The possible role of opiates in women with chronic urinary retention: observations from a prospective clinical study. J Urol, 2012, 188(2): 480-484.
- 41. Seth J, Rintoul-Hoad S, Sahai A. Urethral sphincter injection of botulinum toxin A: a review of its application and outcomes. Low Urin Tract Symptoms, 2018, 10(2): 109-115.
- 42. Huang YH, Chen SL. Concomitant detrusor and external urethral sphincter botulinum toxin-A injections in male spinal cord injury patients with detrusor overactivity and detrusor sphincter dyssynergia. J Rehabil Med, 2022, 54: jrm00264.
- 43. Smith CP, Nishiguchi J, O’Leary M, et al. Single-institution experience in 110 patients with botulinum toxin A injection into bladder or urethra. Urology, 2005, 65(1): 37-41.
- 44. Schurch B, Hauri D, Rodic B, et al. Botulinum-A toxin as a treatment of detrusor-sphincter dyssynergia: a prospective study in 24 spinal cord injury patients. J Urol, 1996, 155(3): 1023-1029.
- 45. Haferkamp A, Schurch B, Reitz A, et al. Lack of ultrastructural detrusor changes following endoscopic injection of botulinum toxin type a in overactive neurogenic bladder. Eur Urol, 2004, 46(6): 784-791.
- 46. Kuo HC. Satisfaction with urethral injection of botulinum toxin A for detrusor sphincter dyssynergia in patients with spinal cord lesion. Neurourol Urodyn, 2008, 27(8): 793-796.
- 47. Panicker JN, Seth JH, Khan S, et al. Open-label study evaluating outpatient urethral sphincter injections of onabotulinumtoxin A to treat women with urinary retention due to a primary disorder of sphincter relaxation (Fowler’s syndrome). BJU Int, 2016, 117(5): 809-813.
- 48. Kennelly M, Dmochowski R, Ethans K, et al. Long-term efficacy and safety of onabotulinumtoxin A in patients with urinary incontinence due to neurogenic detrusor overactivity: an interim analysis. Urology, 2013, 81(3): 491-497.
- 49. Gaillet S, Bardot P, Bernuz B, et al. Five years follow-up study and failures analysis of botulinum toxin repeated injections to treat neurogenic detrusor overactivity. Prog Urol, 2012, 22(17): 1064-1070.
- 50. Bellows S, Jankovic J. Immunogenicity associated with botulinum toxin treatment. Toxins (Basel), 2019, 11(9): 491.
- 51. Jost WH, Benecke R, Hauschke D, et al. Clinical and pharmacological properties of incobotulinumtoxin A and its use in neurological disorders. Drug Des Devel Ther, 2015, 9: 1913-1926.
- 52. Chuang YC, Tyagi P, Huang CC, et al. Urodynamic and immunohistochemical evaluation of intravesical botulinum toxin A delivery using liposomes. J Urol, 2009, 182(2): 786-792.
- 53. Kuo HC, Liu HT, Chuang YC, et al. Pilot study of liposome-encapsulated onabotulinumtoxina for patients with overactive bladder: a single-center study. Eur Urol, 2014, 65(6): 1117-1124.
- 54. Hung FC, Kuo HC. Liposome-encapsulated botulinum toxin A in treatment of functional bladder disorders. Toxins (Basel), 2022, 14(12): 838.