Ординатура / Офтальмология / Английские материалы / The Glaucomas Volume 1 Pediatric Glaucomas_Sampaolesi, Zarate_2009

Goniotomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Trabeculotomy for Chamber Angle Type I . . . . . . . . . . . . 131 Surgery for Refractory Congenital Glaucoma Type II . . . 144

Nonpenetrating Deep Sclerectomy for Late Congenital Glaucoma . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

Valve Devices in Congenital Glaucomas . . . . . . . . . . . . . . 171

Annex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185

In congenital glaucoma, when pathological mesodermal remnants remain, obstructing the filtration area of the chamber angle, this tissue needs to be surgically removed. Taylor [1, 2] was the first to publish Carlos De Vincentiis’s surgical technique for the treatment of glaucoma [3, 4]. Designed in Naples and known as the incision of the angle formed by the iris and the cornea, or internal sclerotomy, this technique had the same requirements as goniotomy, since it was performed with a small sickle-shaped knife (the De Vincentiis knife, specially manufactured to prevent aqueous humor from overflowing), ocular fixation was good, and the incision was nontraumatic and superficial to prevent damage to other structures of the chamber angle. He used the technique for all sorts of glaucomas and it was the first blind goniotomy, though it is actually an ab interno trabeculotomy. It was then abandoned for 30 years, perhaps because it was reported only in a local Italian journal and because its author died soon thereafter. In 1900, Scalinci [5] presented 13 cases of congenital glaucoma successfully operated using this technique.

De Vincentiis’s technique was perfected by Barkan in 1936 [6], who added visualization of the chamber angle through a lens during the surgical procedure; this newly applied surgical procedure was called goniotomy.

There are several interesting points to be mentioned concerning goniotomy. Barkan [7] (Fig. 15.1) described the results of this technique in a sample of 51 children (76 eyes with congenital glaucoma). The procedure, performed in the early stage of congenital glaucoma, was successful in 66 cases and failed in ten. There was optic nerve atrophy only in those cases failing to achieve IOP regulation. The procedure was not performed with a microscope, but with a ×5 loupe. The patients were followed up for 10 years.

Fig. 15.1 Otto Barkan 1887–1958. In 1936, Barkan dramatically changed the poor prognosis of infantile glaucoma with goniotomy

The author stresses the importance of early diagnosis and prompt operation. He states:

It is essential to operate early, before prolonged distention of the eyeball has caused obliteration of Schlemm’s canal. Other important reasons for early diagnosis and prompt operation are: (a) restoration of vision by clearing the cornea …; (b) prevention of the amblyopia resulting from prolonged obstruction of vision by cloudiness of the cornea; (c) prevention of the development of permanent scarring from corneal cloudiness; (d) prevention of injury to the optic nerve caused by prolonged pressure.

The extensive literature authored by Barkan is very interesting [8–12].

Worst [13] provided a detailed description of this technique as well as of the goniotomy lens he designed himself.

In addition, Broughton and Parks [14] used goniotomy as the initial surgical procedure in 34 patients (50 eyes) with congenital glaucoma. They had an overall success rate of 88% with one or more goniotomies after a follow-up period of 15 years. For these authors, refractive error proved to be a valuable indicator of the success of surgery or of disease progression.

Haas [15] edited the proceedings of a symposium on congenital glaucoma where the outcome of the treatment of 329 eyes of 202 patients with the infantile form of congenital glaucoma was discussed. Patients had undergone between one and five goniotomies, with successful IOP regulation in 77% of cases. Barkan, Shaffer and Haas, among others, contributed material to the discussion. As stated by the author: “early diagnosis with early surgery of the angle will make possible a greatly improved visual prognosis” [15].

Morgan et al. [16] reviewed 37 consecutive patients who had undergone at least one goniotomy or filtering surgery, with a success rate of 78%.

Clothier et al. [17] reported the factors that are relevant to the development of amblyopia in congenital glaucoma, such as: (a) persistent corneal edema, (b) anisometropia, and (c) strabismus. In cases with 7 D or more of anisometropia, the amblyopia was profound. All these factors should be identified early, and they stress the importance of preferential visual tests.

Lister [18] studied a sample of 181 eyes treated with goniotomy as the initial operation. The author stresses the differences in prognosis compared to those reported by Anderson in 1939 [19], for whom the prognosis was very poor, since most patients went blind, while in Lister’s sample the IOP was controlled in slightly more than 80% of cases, even considering the most severe cases.

Shaffer [20] also stressed the differences in prognosis from the times of Anderson and the great change observed since the introduction of goniotomy by Barkan, 30 years earlier. He stated that Barkan had actually adapted the De Vicentiis operation (thought to have been reported in 1898). With goniotomy, approximately 85% of cases operated under the age of 1 year achieved IOP normalization. He recommended patching the better eye to counteract amblyopia.

Complications

In a series of 401 goniotomies, Litinsky et al. [21] reported cardiopulmonary arrest in 1.8% of cases as well as apnea, iridodialyses, hyphemas, and anterior synechiae.

Reporting a series of 290 eyes treated at Moorfields Eye Hospital between 1960 and 1979, Cooling et al. [22] observed retinal detachment in 13 eyes.

Surgical Indications

To identify pathological mesodermal remnants and the two main types of chamber angles – vital for deciding which surgical technique to use – the relation between the anatomy, histology, and gonioscopy of normal eyes and those with congenital glaucoma in newborns must be familiar (Chaps. 13, 14).

Surgery is mandatory in all types of congenital glaucoma. In centers such as Shaffer, Hetherington, and Hoskins’s center in San Francisco, specializing in this pathology, which may be the most severe of all glaucomas, any infant with symptoms of congenital glaucoma is examined under general anesthesia directly in the operating room, and if necessary, with the parents’ previous consent, can be operated immediately after the examination, since a delay of days, weeks, or months may turn a small eye into an enlarged one, and, even if surgery succeeds in regulating IOP, the macular and optic nerve alterations lead to impaired visual acuity.

For the first time, I examined a case in which IOP was regulated spontaneously because the tears in the Descemet membrane and the endothelium continued up to the trabecular meshwork. This child has been followed up for 25 years and at present he has normal IOP, visual acuity, and visual field. The tears extended over the trabecular meshwork, thus causing an automatic goniotomy. Dr. Manzitti and Dr. Damel (personal communication) have studied two cases of the spontaneous regulation of IOP.

Lockie et al. [23] studied 61 cases of primary congenital glaucoma in which they detected six cases of spontaneous cures. All the cases had large corneas and tears in the Descemet membrane.

There are two techniques to be used in children’s -eyes in the first 6 months of life:

With angle type I and ocular axial length values 23 mm or less, with no tears in the endothelium and the Descemet membrane or enlarged corneal diameter (see Fig. 13.2, Chap. 13), trabeculotomy is the

-best technique.

With angle type II (refractory congenital glaucomas) and an axial length over 23 mm, enlarged corneal diameter, tears in the endothelium and the Descemet membrane, combined surgery (trabeculotomy + trabeculectomy) is better, because trabeculotomy alone fails to regulate IOP.

Though we have abandoned the practice of goniotomy, the next section provides details since many ophthalmologists still use it.

Goniotomy

The implementation of the De Vincentiis technique can be credited to Barkan [6], who contributed control by means of a specially designed gonioscopic lens, which has taken his name. He also studied the chamber angle in normal children and in those with congenital glaucoma.

The corneal epithelium should be transparent and free of edema, or otherwise, a few drops of alcohol 70% should be applied on the cornea [29] and then the epithelium should be removed with the edge of a knife. A pupil with drug-induced miosis should be preferred.

At the beginning, in 1949, we used the Barkan lens (Fig. 15.2), which was available in two different sizes. We subsequently adopted the different lenses specially designed by Swan (Fig. 15.3), Cardona (Fig. 15.4a), Leydhecker (Fig. 15.4b), and Worst (Fig. 15.5). We have obtained better results with the Worst lens, and, in our opinion, this is the safest. The Worst lens for chamber angle microsurgery is available in two sizes, according to the size of the eye to operate (Fig. 15.5a, b).

Fig. 15.5a,b The Worst gonioscopic lenses for goniotomy with surgical microscope. Two models in their actual sizes in perspective and section views. The tube enters the lens through its upper part and allows the passage of serum to prevent the

formation of air bubbles during the procedure. In a and b, different sizes depending on the dimensions of the eye to be operated

Figure 15.6 shows the appropriate position for the patient, microscope, and surgeon. The anteroposterior axis of the infant’s head should be 45° to the horizontal plane, since this gives perfect visualization of the chamber angle. In Fig. 15.6, gonioscopy is being performed in the nasal area of the chamber angle. The visual axis of the surgeon should be oblique, as shown in the figure; consequently, the axes of the microscope and of the other illumination devices should be slanted by inserting piece A (manufactured by Zeiss, Oberkochen, Germany, based on a drawing and measurements I made for this purpose), between the microscope’s arm and the upper horizontal support. This piece, sketched in the upper right-hand side of the figure, is made of a rod (1) around which piece 2 turns, and in whose hole (3) the microscope’s arm is placed.

The microscope’s axis can thus be slanted as necessary. Some optical devices perform the same tasks by means of prisms, but their cost is higher. The most highly recommended of these was designed by Draeger, in 1970, for the Muller microscopes.

Once all the elements have been arranged, the sketch shows the two main principles of the Worst method. The contact lens has a duct connected to a syringe by means of a thin plastic tube that enables the cavity between the lens and the cornea to be filled with saline solution, thus allowing continuous visibility. The goniotomy used for sweeping the tissue (pathological mesodermal remnants) interposed between the chamber angle and the trabecular meshwork has a duct inside and a hole in its cutting edge. This duct is connected by means of a plastic tube to a bottle of

Fig. 15.6 Goniotomy. Infant’s position at 45°. Using a device to tilt the microscope. A Enlarged at the angle in the top right of the figure. The device (2), with an arm of the microscope put into its hole (3), turns around the rod (A). The tilt is adjusted

by means of the screw (1) (Sampaolesi, personal design and technique, 1970). The arm was specially built for this purpose by Zeiss (Oberkochen, Germany)