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External versus endonasal dacryocystorhinostomy in a specialized lacrimal surgery center
Saudi Journal of Ophthalmology (2014) 28, 36–39
Original Article
External versus endonasal dacryocystorhinostomy in a specialized lacrimal surgery center Vinod Gauba, FRCOphth ⇑
Abstract Purpose: To study the duration of surgery, outcomes, adverse events and success rates of external versus endonasal dacryocystorhinostomy (DCR) surgery in a specialized lacrimal surgery center. Methods: Prospective, interventional case series. Standard external DCR technique was performed. Mechanical endonasal DCR was performed with enlargement of the ostium and full length opening of the lacrimal sac. Surgical time, duration of intubation, incidence of hemorrhage, infection, wound dehiscence; follow-up duration and functional success at the end of follow up were recorded. Results: Functional success and symptomatic relief were equivalent in both procedures. Endonasal DCR surgery was found to be quicker to perform than external DCR surgery. The follow-up duration was comparable in both groups (mean 9 months). Patient satisfaction was significantly higher in the endonasal DCR group (9.3 versus 8.6). Conclusion: Endonasal DCR surgery offers a very attractive alternative to the well established technique of external DCR surgery for the treatment of primary acquired nasolacrimal duct obstruction with equivalent success rates, shorter surgical time and higher patient satisfaction. Keywords: DCR, External, Endoscopic, Epiphora, Success, Lacrimal Ó 2013 Production and hosting by Elsevier B.V. on behalf of Saudi Ophthalmological Society, King Saud University. http://dx.doi.org/10.1016/j.sjopt.2013.11.007
Introduction Dacryocystorhinostomy involves the creation of an alternative route for drainage of tears, between the lacrimal sac and nasal cavity, bypassing the nasolacrimal duct. This is usually performed either by an external approach (external DCR) or through the nasal cavity using an endoscope (endonasal DCR). The external DCR technique was originally described in 19041 and was subsequently modified2 by the addition of suturing of the nasal and lacrimal mucosal flaps in order to form an epithelium-lined fistula. Several case series have estimated the success rate of external DCR to be between 85% and 95%.3–8
The endonasal approach was introduced in 1893 by Caldwell9 and later modified by West10 and Halle.11 During its early days, this approach failed to gain popularity due to lack of technology to allow good access to the nasal cavity. Following the introduction of the nasal endoscope,12 interest in endonasal DCR increased. The procedure, in its present form, was introduced by McDonough et al.13 The literature contains several figures of reported success rates ranging from 63% to 90%.14,15,16 The apparent advantages of endonasal DCR over external DCR are its less invasive nature, shorter operative time and preservation of pump function of the orbicularis oculi muscle due to the absence of an external skin and orbicularis
Received 28 November 2013; accepted 29 November 2013; available online 9 December 2013. Imperial Healthcare Institute, Dubai Healthcare City, Dubai, United Arab Emirates
⇑
Address: 1st Floor, Suite 101, Block A, IbnSina Building (27), Dubai Healthcare City, P.O. Box 505133, Dubai, United Arab Emirates. Tel.: +971 4 439 3737; fax: +971 4 439 3736. e-mail address: [email protected] Peer review under responsibility of Saudi Ophthalmological Society, King Saud University
Production and hosting by Elsevier
Access this article online: www.saudiophthaljournal.com www.sciencedirect.com
37
External versus endonasal dacryocystorhinostomy incision. Absence of an external scar, minimal morbidity and low complication rate have made endonasal DCR popular. The disadvantages of endonasal DCR include a relatively smaller opening between the lacrimal sac and nasal cavity, high equipment cost and steep learning curve and some of these disadvantages are known to influence the success rate. Despite the advantages, the general impression is that endonasal DCR has a lower success rate than external DCR. This study aims to look at this hypothesis further. This study is a prospective interventional case series looking at the procedure, outcomes, adverse events, success rates and patient satisfaction with external and endonasal DCR surgery performed by a sub-specialized surgeon in a lacrimal surgery center.
Materials and methods The study adheres to the tenets of Declaration of Helsinki. Prospective data collection was performed on external and endonasal DCR surgery. All procedures were performed by a single lacrimal surgeon (VG) and all cases had primary acquired nasolacrimal duct obstruction. The external DCR surgery was performed by the standard technique as referenced in the introduction. The mechanical endoscopic endonasal approach included enlargement of the bony ostium using a diamond burr, full length opening of the lacrimal sac and approximation of nasal and lacrimal sac mucosal edges. No sutures were used. Silicone intubation with internal silicone bolster was performed in all external and endonasal DCR cases. All cases were performed under general anesthesia. The surgeon was well experienced in both procedures prior to the start of this study. Data recorded are as follows: 1. Surgical time (in minutes from LA administration to removal of drapes). 2. Symptomatic relief (1–4; 1 = no improvement; 2 = marginal improvement; 3 = considerable improvement; 4 = complete resolution of epiphora symptoms). 3. Post-operative visits-Functional Endoscopic Dye Test (FEDT) or visualization of fluorescein dye at the ostium (Fig. 1). 4. Intraoperative hemorrhage requiring intervention. 5. Post-operative (within 7 days) hemorrhage requiring intervention. 6. Infection. 7. Wound dehiscence. 8. Duration of Follow-up. 9. Time of removal of silastic tube. 10. Patient satisfaction (1 = extremely dissatisfied to 10 = extremely satisfied). The surgery was deemed as successful if at the last followup appointment the patient scored 3 or above for symptom resolution and had fluorescein dye visualization at the nasal opening (i.e. functionally patent).
Figure 1. Endoscopic visualization of fluorescein dye in the nasal cavity. Table 1. Summary of the study results.
Surgical time (min) Symptomatic relief (score out of 4) Fluorescein in nose (functional success) Intra-op hemorrhage Post-op hemorrhage Infection Wound dehiscence Duration of follow-up (months) Silicone intubation (months) Patient satisfaction (out of 10)
External DCR
Endonasal DCR
56 3.45 90.9%
48 3.43 91.3%
18% 9% 4.5% Nil 9 3.2 8.6
13% 8.7% Nil Nil 9.3 3.3 9.3
14 months. The data were collected over a period of 3 years. Both groups were well matched for age and sex. The results’ summary obtained for the 9 data points mentioned in the methods can be seen in Table 1. Graphical display of the results can be seen in Fig. 2 where series 1 is external DCR and series 2 is endonasal DCR. The graphical display indicates that both groups are comparable in all of the collected data points. Further analysis of the results revealed that endonasal DCR surgery took significant less time to perform than external DCR surgery. There was no statistically significant difference in symptomatic relief in both groups. The postoperative visualization of fluorescein dye at the nasal opening was also comparable in both groups. A slightly higher incidence of intra-operative hemorrhage requiring intervention was noted in the external DCR group. Post-operative hemorrhage requiring intervention was similar in both groups. There was one case of cellulitis around the wound in the external DCR group whereas no cases of infection were noted in the endonasal group. No cases of wound dehiscence were noted in either group. The follow-up duration was comparable in both groups. Patient satisfaction was significantly higher in the endonasal group. The duration of silicone intubation was comparable in both groups.
Results Discussion A total of 45 patients were included in the study. 22 of which underwent external DCR surgery and 23 underwent endonasal DCR surgery. Follow-up ranged from 3 to
Endonasal DCR had gained increasing popularity and acceptance in the last decade for the treatment of primary
38
V. Gauba 100 90 80 70 60 Series1
50
Series2
40 30 20 10 0 1
2
3
4
5
6
7
8
9
10
Figure 2. Bar chart visually depicting the study results.
nasolacrimal duct obstruction. A strong driving force for this decision in the Middle East and North Africa (MENA) region is the general patient preference to avoid a facial scar particularly in such a patient cohort where keloid formation is not infrequent. Various interventional cohort studies have studied the success of this technique compared to the traditional external DCR. A retrospective cohort study14 comparing success rates of endonasal (86 cases) and external (90 cases) DCR surgeries found statistically significant success rates with endonasal DCR (84% versus 70%, P = 0.03) at a mean follow-up period of seven months. Cokkeser et al.4 also found comparable success rates between external and endonasal DCR (90% versus 88%). Dolman et al.17 in a study looking at external DCR and non-laser endonasal DCR, also found both procedures to have equivalent success rates (90% versus 89%). His group also found the nasal approach more rapid and more acceptable to patients who had an alternative technique used on the other side. Meanwhile a retrospective comparative cohort study18 found a higher success rate with external DCR when compared to endonasal DCR (82% versus 58%). However, it also found that the rate of symptom relief was similar in both groups. This study suggests that both external and endonasal DCR surgeries have a high success rate with low incidence of any adverse events and high patient satisfaction and are generally comparable across all the measured parameters. The success rates in both groups were found to be equivalent meanwhile patient satisfaction was noted to be slightly higher with endonasal DCR surgery and this difference was significant. The latter may be higher due to the shorter surgery time; lack of external incision; quicker return to work and lesser follow-up appointments (no suture removal). Surgical technique and meticulous attention to detail are significant contributors to achieving a high success rate in DCR surgery. Endonasal DCR surgery has a steeper learning curve when compared to external DCR surgery. The results obtained in this study may be partly due to the extensive experience of the lacrimal surgeon in both procedures.
Conclusions Endonasal DCR is a procedure of increasing interest due to its minimally invasive nature, high patient satisfaction and high success rates. This study suggests that both procedures have a high success rate and are equivalent in producing symptomatic relief of epiphora. The shorter duration of surgery, absence of any visible scar along with equivalent success rates to external DCR surgery, make endonasal DCR a highly attractive procedure for the treatment of primary acquired nasolacrimal duct obstruction.
Conflict of interest The authors declared that there is no conflict of interest.
References 1. Toti A. Nuovometodoconservatore di cura radicle dellesuppurazonicroniche del saccolacrimale (Dacriocistorinostomia). Clin Mod Firenze 1904;10:385–7. 2. Dupuy-Dutemps L, Bourguet J. Procedeplastique de dacryocystorhinostomie et ses resultants. Ann Oculist 1921;158:241–61. 3. Becker BB. Dacryocystorhinostomy without flaps. Ophthalmic Surg 1988;19(6):419–27. 4. Cokkeser Y, Evereklioglu C, Er H. Comparative external versus endoscopic dacryocystorhinostomy: results in 115 patients (130 eyes). Otolaryngol Head Neck Surg 2000;123(4):488–91. 5. Dressner SC, Klussman KG, Meyer DR, Linberg JV. Outpatient dacryocystorhinostomy. Ophthalmic Surg 1991;22(4):222–4. 6. Emmerich KH, Busse H, Meyer- Rusenberg HW. Dacryocystorhinostomia externa. Technique, indications and results. Ophthalmologe 1994;91(3):395–8. 7. Rosen N, Sharir M, Moverman DC, Rosner M. Dacryocystorhinostomy with silicone tubes: evaluation of 253 cases. Ophthalmic Surg 1989;20(2):115–9. 8. Tarbet KJ, Custer PL. External dacryocystorhinostomy: surgical success, patient satisfaction and economic cost. Ophthalmology 1995;102(7):1065–70. 9. Caldwell GW. Two new operations for obstruction of the nasal duct. N Y Med J 1893;57:581–2. 10. West JM. A window resection of the nasal duct in cases of stenosis. Trans Am Ophthalmol Soc 1910;12(Pt 2):654–8.
External versus endonasal dacryocystorhinostomy 11. Halle M. Zurintranasalen operation am tranensack. Arch Laryngol Otol Rhinol 1914;28:256–66. 12. Stammberger H. Endoscopic endonasal surgery: concepts in treatment of recurring rhinosinusitis. Part II. Surgical technique. Otolaryngol Head Neck Surg 1986;94(2):147–56. 13. McDonough M, Meiring JH. Endoscopic transnasal dacryocystorhinostomy. J Laryngol Otol 1989;103(6):585–7. 14. Ben Simon GJ, Joseph J, Lee S, Schwarcz RM, McCann JD, Goldberg RA. External versus endoscopic dacryocystorhinostomy for acquired nasolacrimal duct obstruction in a tertiary referral centre. Ophthalmology 2005;112(8):1464–8. 15. Hartikainen J, Grenman R, Puukka P, Seppä H. Prospective randomized comparison of external dacryocystorhinostomy and
39 endonasal laser dacryocystorhinostomy. Ophthalmology 1998; 105(6):1106–13. 16. Sham CL, van Hasselt CA. Endoscopic terminal dacryocystorhinostomy. Laryngoscope 2000;110(6):1045–9. 17. Dolman PJ. Comparison of external dacryocystorhinostomy with non-laser endonasal dacryocystorhinostomy. Ophthalmology 2003; 110(1):78–84. 18. Ibrahim HA, Batterbury M, Banhegyi G, McGalliard J. Endonasal laser dacryocystorhinostomy and external Dacryocystorhinostomy: outcome profile in a general ophthalmic service unit: a comparative retrospective study. Ophthalmic Surg Lasers 2001;32(3):220–7.
Original Article
External versus endonasal dacryocystorhinostomy in a specialized lacrimal surgery center Vinod Gauba, FRCOphth ⇑
Abstract Purpose: To study the duration of surgery, outcomes, adverse events and success rates of external versus endonasal dacryocystorhinostomy (DCR) surgery in a specialized lacrimal surgery center. Methods: Prospective, interventional case series. Standard external DCR technique was performed. Mechanical endonasal DCR was performed with enlargement of the ostium and full length opening of the lacrimal sac. Surgical time, duration of intubation, incidence of hemorrhage, infection, wound dehiscence; follow-up duration and functional success at the end of follow up were recorded. Results: Functional success and symptomatic relief were equivalent in both procedures. Endonasal DCR surgery was found to be quicker to perform than external DCR surgery. The follow-up duration was comparable in both groups (mean 9 months). Patient satisfaction was significantly higher in the endonasal DCR group (9.3 versus 8.6). Conclusion: Endonasal DCR surgery offers a very attractive alternative to the well established technique of external DCR surgery for the treatment of primary acquired nasolacrimal duct obstruction with equivalent success rates, shorter surgical time and higher patient satisfaction. Keywords: DCR, External, Endoscopic, Epiphora, Success, Lacrimal Ó 2013 Production and hosting by Elsevier B.V. on behalf of Saudi Ophthalmological Society, King Saud University. http://dx.doi.org/10.1016/j.sjopt.2013.11.007
Introduction Dacryocystorhinostomy involves the creation of an alternative route for drainage of tears, between the lacrimal sac and nasal cavity, bypassing the nasolacrimal duct. This is usually performed either by an external approach (external DCR) or through the nasal cavity using an endoscope (endonasal DCR). The external DCR technique was originally described in 19041 and was subsequently modified2 by the addition of suturing of the nasal and lacrimal mucosal flaps in order to form an epithelium-lined fistula. Several case series have estimated the success rate of external DCR to be between 85% and 95%.3–8
The endonasal approach was introduced in 1893 by Caldwell9 and later modified by West10 and Halle.11 During its early days, this approach failed to gain popularity due to lack of technology to allow good access to the nasal cavity. Following the introduction of the nasal endoscope,12 interest in endonasal DCR increased. The procedure, in its present form, was introduced by McDonough et al.13 The literature contains several figures of reported success rates ranging from 63% to 90%.14,15,16 The apparent advantages of endonasal DCR over external DCR are its less invasive nature, shorter operative time and preservation of pump function of the orbicularis oculi muscle due to the absence of an external skin and orbicularis
Received 28 November 2013; accepted 29 November 2013; available online 9 December 2013. Imperial Healthcare Institute, Dubai Healthcare City, Dubai, United Arab Emirates
⇑
Address: 1st Floor, Suite 101, Block A, IbnSina Building (27), Dubai Healthcare City, P.O. Box 505133, Dubai, United Arab Emirates. Tel.: +971 4 439 3737; fax: +971 4 439 3736. e-mail address: [email protected] Peer review under responsibility of Saudi Ophthalmological Society, King Saud University
Production and hosting by Elsevier
Access this article online: www.saudiophthaljournal.com www.sciencedirect.com
37
External versus endonasal dacryocystorhinostomy incision. Absence of an external scar, minimal morbidity and low complication rate have made endonasal DCR popular. The disadvantages of endonasal DCR include a relatively smaller opening between the lacrimal sac and nasal cavity, high equipment cost and steep learning curve and some of these disadvantages are known to influence the success rate. Despite the advantages, the general impression is that endonasal DCR has a lower success rate than external DCR. This study aims to look at this hypothesis further. This study is a prospective interventional case series looking at the procedure, outcomes, adverse events, success rates and patient satisfaction with external and endonasal DCR surgery performed by a sub-specialized surgeon in a lacrimal surgery center.
Materials and methods The study adheres to the tenets of Declaration of Helsinki. Prospective data collection was performed on external and endonasal DCR surgery. All procedures were performed by a single lacrimal surgeon (VG) and all cases had primary acquired nasolacrimal duct obstruction. The external DCR surgery was performed by the standard technique as referenced in the introduction. The mechanical endoscopic endonasal approach included enlargement of the bony ostium using a diamond burr, full length opening of the lacrimal sac and approximation of nasal and lacrimal sac mucosal edges. No sutures were used. Silicone intubation with internal silicone bolster was performed in all external and endonasal DCR cases. All cases were performed under general anesthesia. The surgeon was well experienced in both procedures prior to the start of this study. Data recorded are as follows: 1. Surgical time (in minutes from LA administration to removal of drapes). 2. Symptomatic relief (1–4; 1 = no improvement; 2 = marginal improvement; 3 = considerable improvement; 4 = complete resolution of epiphora symptoms). 3. Post-operative visits-Functional Endoscopic Dye Test (FEDT) or visualization of fluorescein dye at the ostium (Fig. 1). 4. Intraoperative hemorrhage requiring intervention. 5. Post-operative (within 7 days) hemorrhage requiring intervention. 6. Infection. 7. Wound dehiscence. 8. Duration of Follow-up. 9. Time of removal of silastic tube. 10. Patient satisfaction (1 = extremely dissatisfied to 10 = extremely satisfied). The surgery was deemed as successful if at the last followup appointment the patient scored 3 or above for symptom resolution and had fluorescein dye visualization at the nasal opening (i.e. functionally patent).
Figure 1. Endoscopic visualization of fluorescein dye in the nasal cavity. Table 1. Summary of the study results.
Surgical time (min) Symptomatic relief (score out of 4) Fluorescein in nose (functional success) Intra-op hemorrhage Post-op hemorrhage Infection Wound dehiscence Duration of follow-up (months) Silicone intubation (months) Patient satisfaction (out of 10)
External DCR
Endonasal DCR
56 3.45 90.9%
48 3.43 91.3%
18% 9% 4.5% Nil 9 3.2 8.6
13% 8.7% Nil Nil 9.3 3.3 9.3
14 months. The data were collected over a period of 3 years. Both groups were well matched for age and sex. The results’ summary obtained for the 9 data points mentioned in the methods can be seen in Table 1. Graphical display of the results can be seen in Fig. 2 where series 1 is external DCR and series 2 is endonasal DCR. The graphical display indicates that both groups are comparable in all of the collected data points. Further analysis of the results revealed that endonasal DCR surgery took significant less time to perform than external DCR surgery. There was no statistically significant difference in symptomatic relief in both groups. The postoperative visualization of fluorescein dye at the nasal opening was also comparable in both groups. A slightly higher incidence of intra-operative hemorrhage requiring intervention was noted in the external DCR group. Post-operative hemorrhage requiring intervention was similar in both groups. There was one case of cellulitis around the wound in the external DCR group whereas no cases of infection were noted in the endonasal group. No cases of wound dehiscence were noted in either group. The follow-up duration was comparable in both groups. Patient satisfaction was significantly higher in the endonasal group. The duration of silicone intubation was comparable in both groups.
Results Discussion A total of 45 patients were included in the study. 22 of which underwent external DCR surgery and 23 underwent endonasal DCR surgery. Follow-up ranged from 3 to
Endonasal DCR had gained increasing popularity and acceptance in the last decade for the treatment of primary
38
V. Gauba 100 90 80 70 60 Series1
50
Series2
40 30 20 10 0 1
2
3
4
5
6
7
8
9
10
Figure 2. Bar chart visually depicting the study results.
nasolacrimal duct obstruction. A strong driving force for this decision in the Middle East and North Africa (MENA) region is the general patient preference to avoid a facial scar particularly in such a patient cohort where keloid formation is not infrequent. Various interventional cohort studies have studied the success of this technique compared to the traditional external DCR. A retrospective cohort study14 comparing success rates of endonasal (86 cases) and external (90 cases) DCR surgeries found statistically significant success rates with endonasal DCR (84% versus 70%, P = 0.03) at a mean follow-up period of seven months. Cokkeser et al.4 also found comparable success rates between external and endonasal DCR (90% versus 88%). Dolman et al.17 in a study looking at external DCR and non-laser endonasal DCR, also found both procedures to have equivalent success rates (90% versus 89%). His group also found the nasal approach more rapid and more acceptable to patients who had an alternative technique used on the other side. Meanwhile a retrospective comparative cohort study18 found a higher success rate with external DCR when compared to endonasal DCR (82% versus 58%). However, it also found that the rate of symptom relief was similar in both groups. This study suggests that both external and endonasal DCR surgeries have a high success rate with low incidence of any adverse events and high patient satisfaction and are generally comparable across all the measured parameters. The success rates in both groups were found to be equivalent meanwhile patient satisfaction was noted to be slightly higher with endonasal DCR surgery and this difference was significant. The latter may be higher due to the shorter surgery time; lack of external incision; quicker return to work and lesser follow-up appointments (no suture removal). Surgical technique and meticulous attention to detail are significant contributors to achieving a high success rate in DCR surgery. Endonasal DCR surgery has a steeper learning curve when compared to external DCR surgery. The results obtained in this study may be partly due to the extensive experience of the lacrimal surgeon in both procedures.
Conclusions Endonasal DCR is a procedure of increasing interest due to its minimally invasive nature, high patient satisfaction and high success rates. This study suggests that both procedures have a high success rate and are equivalent in producing symptomatic relief of epiphora. The shorter duration of surgery, absence of any visible scar along with equivalent success rates to external DCR surgery, make endonasal DCR a highly attractive procedure for the treatment of primary acquired nasolacrimal duct obstruction.
Conflict of interest The authors declared that there is no conflict of interest.
References 1. Toti A. Nuovometodoconservatore di cura radicle dellesuppurazonicroniche del saccolacrimale (Dacriocistorinostomia). Clin Mod Firenze 1904;10:385–7. 2. Dupuy-Dutemps L, Bourguet J. Procedeplastique de dacryocystorhinostomie et ses resultants. Ann Oculist 1921;158:241–61. 3. Becker BB. Dacryocystorhinostomy without flaps. Ophthalmic Surg 1988;19(6):419–27. 4. Cokkeser Y, Evereklioglu C, Er H. Comparative external versus endoscopic dacryocystorhinostomy: results in 115 patients (130 eyes). Otolaryngol Head Neck Surg 2000;123(4):488–91. 5. Dressner SC, Klussman KG, Meyer DR, Linberg JV. Outpatient dacryocystorhinostomy. Ophthalmic Surg 1991;22(4):222–4. 6. Emmerich KH, Busse H, Meyer- Rusenberg HW. Dacryocystorhinostomia externa. Technique, indications and results. Ophthalmologe 1994;91(3):395–8. 7. Rosen N, Sharir M, Moverman DC, Rosner M. Dacryocystorhinostomy with silicone tubes: evaluation of 253 cases. Ophthalmic Surg 1989;20(2):115–9. 8. Tarbet KJ, Custer PL. External dacryocystorhinostomy: surgical success, patient satisfaction and economic cost. Ophthalmology 1995;102(7):1065–70. 9. Caldwell GW. Two new operations for obstruction of the nasal duct. N Y Med J 1893;57:581–2. 10. West JM. A window resection of the nasal duct in cases of stenosis. Trans Am Ophthalmol Soc 1910;12(Pt 2):654–8.
External versus endonasal dacryocystorhinostomy 11. Halle M. Zurintranasalen operation am tranensack. Arch Laryngol Otol Rhinol 1914;28:256–66. 12. Stammberger H. Endoscopic endonasal surgery: concepts in treatment of recurring rhinosinusitis. Part II. Surgical technique. Otolaryngol Head Neck Surg 1986;94(2):147–56. 13. McDonough M, Meiring JH. Endoscopic transnasal dacryocystorhinostomy. J Laryngol Otol 1989;103(6):585–7. 14. Ben Simon GJ, Joseph J, Lee S, Schwarcz RM, McCann JD, Goldberg RA. External versus endoscopic dacryocystorhinostomy for acquired nasolacrimal duct obstruction in a tertiary referral centre. Ophthalmology 2005;112(8):1464–8. 15. Hartikainen J, Grenman R, Puukka P, Seppä H. Prospective randomized comparison of external dacryocystorhinostomy and
39 endonasal laser dacryocystorhinostomy. Ophthalmology 1998; 105(6):1106–13. 16. Sham CL, van Hasselt CA. Endoscopic terminal dacryocystorhinostomy. Laryngoscope 2000;110(6):1045–9. 17. Dolman PJ. Comparison of external dacryocystorhinostomy with non-laser endonasal dacryocystorhinostomy. Ophthalmology 2003; 110(1):78–84. 18. Ibrahim HA, Batterbury M, Banhegyi G, McGalliard J. Endonasal laser dacryocystorhinostomy and external Dacryocystorhinostomy: outcome profile in a general ophthalmic service unit: a comparative retrospective study. Ophthalmic Surg Lasers 2001;32(3):220–7.