Routine punctoplasty: isn’t it time we preserved the integrity of the punctum?

ABSTRACT

Punctoplasty is a common procedure in the management of punctal stenosis and was first described by Sir William Bowman in 1853. Several types of punctoplasty are described, and include 1-snip, 2-snip, triangular 3-snip, rectangular 3-snip and 4-snip procedures. The understanding of the anatomy and physiology of the punctum has greatly improved in the last decade aided by electron microscopic and molecular techniques. The use of minimally invasive modalities for primary cases is on the rise with successful preservation of the physiological functions of the punctum and canaliculus. The paper reviews the current anatomical and physiological evidence to present an alternative perspective. Given our evolving understanding, it may be time to debate the practice of performing routine punctoplasty.

KEYWORDS:

• 1-snip
• 3-snip
• lacrimal
• punctal stenosis
• punctoplasty
• punctum

I. Historical perspectives

Punctal stenosis causing epiphora is a common lacrimal disorder that has been addressed surgically for at least 168 years; punctoplasty was first described by Sir William Bowman in 1853.^1,2 Bowman’s description was that of a single snip procedure, involving slitting the canaliculus. This technique was reiterated by Arlit in 1874.² Hoffman, in 1904 was one of the earliest to suggest a three-snip procedure.³ Graves in 1926 criticized the three-snip procedure and proposed his technique of posterior ampullotomy using Critchett’s grooved probe.⁴ Graves believed that unlike Bowman’s method, his technique did not alter the capillary action of the canaliculi. Thomas in 1951 refined it to the modern 3-snip procedure, which was suggested to him by his colleague David Hardie.⁵ The procedure saw further refinement by Viers in 1955.⁶ However, Jones in 1962 reintroduced the modern 1-snip and heavily criticized the 3-snip procedures as unphysiological.⁷ For recurrent or refractory cases and canaliculitis, Jones proposed a 2-snip procedure with a small horizontal arm medially without removing part of the punctum or ampulla. The arguments by Jones were counteracted by Viers and Cassady, separately.⁷ In 1967, Hughes and Maris proposed a punch punctoplasty that involved targeting the ampulla, which was re-popularized by Edelstein and Reiss in 1992 using the ‘Reiss punch.^8,9 To enhance the success of the 1-snip, Dolin and Hecht in 1986 proposed a suturing technique to keep the freshened edges of 1-snip procedure separated.¹⁰ Offutt and Cowen in 1993 proposed their technique of microsurgical punctoplasty, which involved externalization of the vertical canaliculus.³ The same year, Lam and Tessler proposed adjunctive use of mitomycin C with a 3-snip punctoplasty in a patient who failed a 1-snip procedure earlier.¹¹ The classical triangular 3-snip punctoplasty remained the most popular technique of punctoplasty for decades. In 2009, Chak and Irvine proposed their technique of a rectangular 3-snip punctoplasty as a more physiological procedure.¹² Kim et al. in 2012 proposed a 4-snip punctoplasty in cases of severe punctal stenosis. Their approach modified the 3-snip rectangular technique to include a portion of the horizontal canaliculus.¹³ The debate continues as to which punctoplasty procedure is the best or, indeed, is punctoplasty the best solution for punctal stenosis?

II. Current knowledge of the anatomy and physiology of the punctum: considerations against performing punctoplasty

The punctum is an anatomical structure representing the beginning of the lacrimal drainage system. It lies on a fibrous mound, the ‘lacrimal papilla.’ Although routinely believed to measure 0.2–0.4 mm, there are wide variations in its dimensions, which are influenced by several factors such as age, gender, race, and ethnicity.^14,15 Studies assessing the natural evolution of punctal parameters from the 1^st to 8^th decade in a normal population have shown differences between genders as well as between the upper and lower puncta.¹⁶ From childhood to old age, typical changes have been documented in size, punctal papilla, density of peri-punctal fibrous layers, peri-punctal vascularity, and the white punctal zones.¹⁶

The lacrimal punctum is surrounded by a dense ring of fibrous tissue that provides support and integrity to the punctum and facilitates its functions. The muscle of Riolan was earlier believed to pass through the tarsal plate along with the dense fibrous tissue to insert into the lateral aspect of the punctum and vertical canaliculus.¹⁷ In a detailed cadaveric study in 2011, Kakizaki et al¹⁸ demonstrated the lacrimal punctum and the vertical canaliculus to be a part of the tarsal plate. This partly validated Whitnall’s¹⁹ earlier work and that of others.²⁰ They further demonstrated that the fibrous tissue and muscle of Riolan surround the punctum and the vertical canaliculus both medially and laterally.²¹ Ultrastructural mapping of a normal punctum revealed a well-defined elevated junction between the inner punctal surface and the beginning of the vertical canaliculus. The mucosa on either side of the junction was distinct with rugae distal to the junction.²² Each of these areas are believed to be anatomically and functionally distinct.

The pars lacrimalis of musculus orbicularis oculi (lacrimal portion of the orbicularis oculi muscle) or tensor tarsi, was first noted by the French anatomist Jacques-Francois-Marie Duverney in 1745 and later by Rosenmüller in 1805. Although eponymously called the ‘Horner’s muscle’ after its description by William E. Horner in 1822, it has been proposed to be renamed as Horner-Duverney’s muscle.^23,24 Recent electron microscopy and 3D histology have demonstrated that at its insertion, the Horner-Duverney’s (HD) muscle continues to encircle the lacrimal punctum and the vertical canaliculus without a separate ‘muscle of Riolan’ (Figure 1 and Figure 2).²⁴ However, the arrangement at the lacrimal punctum constitutes both circular and vertical muscle fibers that partly extend into the peri-punctal area in a scissoring pattern (Figure 1). This scissoring pattern gets exaggerated around the vertical canaliculus and becomes denser and more parallel as it continues around the horizontal canaliculus.²⁴ The density of the connective tissue regularly alters along the entire course of the muscle. The HD muscle demonstrated a typical equal distribution of type I and type IIb fibers and showed a dense sensory, adrenergic and cholinergic innervation.²⁴

Figure 1. Schematic illustration of the Horner-Duverney’s muscle: Note the criss-cross pattern of the muscle arrangement encircling the punctum and vertical canaliculus.

Figure 2. Three-dimensional volume rendered image of the punctum. Note the continuation of Horner-Duverney’s muscle right up to the punctum (yellow arrow) in an extensive criss-cross manner. Also note the dense connective tissue (grey area).

In the context of this current anatomical understanding, punctoplasty is likely to alter the anatomy to potentially impact the physiological functions of the proximal lacrimal drainage pathways. There are six arguments for believing so. Firstly, the tough fibrous ring supports the driving force that creates a negative pressure within the canaliculi and provides the structural buttress needed to maintain the desired punctal position in the lacus lacrimalis. All kinds of incisional punctoplasty procedures violate this fibrous ring to varying degrees. Secondly, as shown recently, the HD muscle continues to insert as high as the punctum, and any irreversible violation of the punctum integrity would logically impact the driving force for propagating tear drainage. Thirdly, there is fundamental evidence now to suggest that the crisscross pattern of the HD muscle at the punctum is responsible for punctal occlusion during eyelid closure. The mechanism is akin to fish-mouth closure (Figure 1). Punctoplasty would potentially have functional consequences on the loss of punctal occlusion during eyelid closure. Fourth, a 3 or 4-snip punctoplasty would cause irreversible loss of a part of the well-defined puncto-canalicular junction and distinct mucosa on either side of it. Fifth, a 3 or 4-snip punctoplasty may potentially cause varying degrees of neural denervation in a critical area with subsequent functional implications. Neural innervation disturbances as seen in paralytic epiphora, partly support such an argument. Lastly, an incisional punctoplasty may potentially disrupt several natural age-related punctal changes that may be desirable in an aging individual with concurrent dry eye.

III. Current knowledge of pathophysiology and treatment of punctal stenosis: considerations against performing punctoplasty

Punctal stenosis is a common disorder of the proximal lacrimal pathway and constitutes 3–17% of all lacrimal drainage disorders in large epidemiology studies.^25,26 Recent ultrastructural studies have shown widespread fibrosis and inflammation, which may be severe in 30% of cases.²⁷ Extensive and irregular laying of collagen cross-bundles with mononuclear inflammatory infiltration of the bundles and inter- and intracellular edema in the vicinity of fibroblast has been demonstrated.²⁷

Punctal stenosis remains the main indication for punctoplasty, the outcomes of which vary in part based upon the precise procedure. Anatomical and functional success varies between 31.2%-96.2% and 18.7–93.3%.^{11–13,28–34} Assessment of punctoplasty outcomes is complex owing to the lack of a standard definition of punctal stenosis, a large range of punctal size in the normal population, several variations in surgical techniques, different stages of the disease, and poor data on adjunctive modalities. Although significant dysfunctions were reported in short-term, long-term functional epiphora and other defects from performing punctoplasties remain unclear. Reported complications following punctoplasty include fibrosis, restenosis, and stent extrusions. These are more likely in the scenario of eyelid cicatricial changes. Given the presence of inflammation and fibrosis associated with punctal stenosis, it is not unreasonable to expect this to increase in response to an incisional insult following punctoplasty. Whilst several steps may be taken to either reduce or manage these complications, it may be preferable to consider an ounce of prevention over a pound of cure.³⁵

IV. Punctoplasty in canaliculitis

A combination of punctoplasty and canaliculotomy is commonly used in the management of infective canaliculitis. While the clinical outcomes in terms of resolution of infection are excellent compared to those of medical management alone, persistence or recurrence occurs in 33–100%.^36,37 However, the functional consequences of punctoplasty and canaliculotomy have not been studied in detail.^36–40 The combination of incision of the punctum as well as the canaliculus would potentially have a cumulative detrimental impact upon the physiology of the lacrimal pump and capillary action of the canaliculus beyond that of each individually. Lacrimal pump dysfunction, canalicular fibrosis and fistula formation are documented complications.^41–44 This has prompted the increased use of punctum-sparing canaliculotomy techniques such as focal canaliculotomy or non-incisional canalicular curettage with encouraging outcomes.^41–44

V. Alternative modalities to incisional punctoplasty

Non-incisional modalities are being increasingly investigated and practiced in the management of punctal stenosis. They include simple mechanical punctal dilatation, perforated punctal plugs, punctal dilatation with mini-monoka or bicanalicular stents, and balloon punctoplasty.^45,46 The use of stents is well-established now as an alternative modality to incisional punctoplasty and has been found to be simple, safe, equally effective as snip punctoplasties, and minimally invasive with preservation of the punctal anatomy and lacrimal pump functions.^46–49 Stents also have the potential advantage of simultaneously addressing associated canalicular stenosis. Quality of life assessment has demonstrated monoka stents to be very effective (93% anatomical and functional success) in managing primary punctal stenosis.⁵⁰ The use of balloon punctoplasty is recently being investigated as an alternate option.^51,52 Although initial results appear promising, well-designed studies are underway to assess their utility in the management of primary punctal stenosis.

VI. Conclusion

The paper reviews the current anatomical and physiological evidence to present an alternate perspective on routine punctoplasty. In light of the evidence discussed, the authors propose that while punctoplasty can continue to be performed for recurrent or recalcitrant cases of punctal stenosis and canaliculitis, the indications for a 3-snip or 4-snip-punctoplasty be critically analyzed for routine punctoplasty. The use of minimally invasive modalities for primary cases is on the rise with successful preservation of the physiological functions of the punctum and canaliculus. We still do not have a detailed understanding of punctal and canalicular functions. A better understanding would translate to better patient management in the future. To quote Dr Lester. T. Jones, “Only too often we seem willing to attack a normal structure instead of the abnormal one that is the cause of the disease. This is certainly true of the ‘three-snip’ operation. The surgeon apparently had assumed that if one ‘three-snip operation’ works so well on a single canaliculus, two would work twice as well. Perhaps we should call this the ‘six-snip’ operation. This patient with the four crippled canaliculi, now wants me to cure his epiphora. Gentlemen, how would any of you like to be in my predicament?”⁷ Given our evolving understanding of the anatomy and physiology of the punctum and canaliculus, it may be time to debate the performance of routine punctoplasty. It may be preferable to consider an ounce of prevention over a pound of cure.

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Funding

This work was supported by the Hyderabad Eye Research Foundation.