|Year : 1994 | Volume
| Issue : 1 | Page : 37-42
Practical aspects in the setting up of a vitreo-retinal unit
Sankara Nethralaya, Madras, India
Sankara Nethralaya, Madras
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Gopal L. Practical aspects in the setting up of a vitreo-retinal unit. Indian J Ophthalmol 1994;42:37-42
| I. INTRODUCTION|| |
Modern vitreous surgery owes its origin to Machemer. His famous experiments in his garage using eggs, have paved the way for the revolutionary developments in this speciality. He showed that removal of the vitreous did not compromise the functioning of the eye. Since then rapid strides have taken place especially in instrumentation. The bulky, unwieldy multifunction probes such as the VISC and vitreophage have now been replaced by the standard 20 gauge instruments such as ocutome and microvit. Important advances have also occurred in the system for visualization during surgery. The indirect ophthalmoscope which tied up one hand of the surgeon for holding the condensing lens has since been replaced by the operating microscope with all its advantages. Bimanual surgery has thus become possible. Using three different ports for infusion, endoillumination and the active instrument have now become the standard procedure.
The benefits of vitreous surgery are obvious from the ever increasing list of indications for these procedures. Diseases which were hitherto incurable have become relatively easy to manage by these surgical techniques. Clearing the vitreous opacities and managing complicated retinal detachments are the most common indications for vitrectomy among posterior segment disorders. However, management of certain anterior segment disorders has also improved with the availability of vitrectomy techniques. Diseases such as aphakic bullous keratopathy, vitreous wick syndrome, dislocated and subluxated lenses, dislocated pseudophakos and dense pupillary membranes, employ vitrectomy techniques for proper management. Anterior segment ocular trauma with lens-vitreous admixture is a typical example of a condition that can be most elegantly managed by a combination of repair with pars plana lensectomy and vitrectomy. This minimises the incidence of post-traumatic sequelae such as fibrous ingrowth and pupillary membrane formation.
The growth of this speciality has been made possible by the development of new instrumentation and improved techniques. Cost being not a restrictive factor, vitreo-retinal surgery as a speciality has spread rapidly to most of the major ophthalmic institutions in the developed countries of the world. In contrast, the development of this subspeciality of ophthalmology in our country has been rather slow paced. Until a few years ago, it was restricted to very few centres. Of late, there has been a significant increase in interest in this speciality among ophthalmologists. More and more centres are training young ophthalmologists in vitreo-retinal surgery and developing the necessary infrastructure despite high initial costs. It is also encouraging to see individual ophthalmologists establishing full-fledged vitreo-retinal units. This recent trend not withstanding, there is a definite need for more advanced centres catering to this speciality in India.
The vitreo-retinal surgeon must be well trained at an advanced centre in all aspects of vitreo-retinal problems. It is not advisable for a general ophthalmologist to practise vitreo-retinal surgery as part-time indulgence. The tremendous pace of development in this speciality warrants a full-time involvement. Certain qualities should be acquired by the surgeon for the successful practice of vitreo-retinal surgery. In view of the relatively long duration and unpredictable intraoperative course of each surgery, patience is a basic prerequisite for the surgeon. If one is impatient, and too time conscious, there will be a tendency to compromise on the quality of surgery. This can be exemplified by surgery for proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR). The incidence of relaxing retinotomies in retinal detachment with PVR can be brought to a minimum with meticulous dissection of pre- and subretinal membranes, especially in the relatively inaccessible periphery. Likewise, in surgery for tractional retinal detachment in PDR intraoperative bleeding very often tends to interfere with proper dissection. Here again, patient and careful removal of clots allows one to complete the procedure without too many iatrogenic retinal breaks.
Attention to detail is another quality required for a vitreo-retinal surgeon. This is especially important when the unit is in initial stages of evolution. A "system" should be established not only for smooth operational efficiency but also for periodic monitoring. This should lay special emphasis on finer details of every procedure. One such critical area concerns sterilization.
Unlike in cataract surgery, vitreo-retinal surgery is expected to be successful in only a modest percentage of cases. Recurrences of problems are not uncommon, requiring additional surgical procedures. The visual results are also not expected to be as gratifying as in cataract surgery. All this makes it necessary for the surgeon to be prepared for experiences that may be frustrating at times.
A trained assistant is highly desirable to assist in these surgical procedures. However, most often, qualified ophthalmologists are available in this role for only short periods as trainees. This entails inexperienced surgeons training as assistants at regular intervals. Hence, a well trained nurse assistant is mandatory during surgery.
The nurse should be trained to perform the following tasks as a rule:
To assist in all vitreo-retinal cases
To be able to assemble and dismantle the instruments such as vitrectomy cutter, vitreous scissors,vitreous forceps, etc.
Should be knowledgeable in cleaning and packing these delicate instruments
Should know how to load the expansile gas (SF 6 , C3 F s ) in the syringe and prepare the exact concentration of its mixture with air needed for flushing the eye
Should have working knowledge of the scleral buckling materials and be able to identify them
Operating Room Assistants
The presence of a circulating nurse in the operating room is an excellent concept. But from the practical point of view one may not be able to employ a qualified nurse as a circulating nurse. Hence, operating room assistants can be employed and trained to perform these tasks. The OR assistants should be able to perform the following tasks:
Assist the anaesthetist during intubation and extubation
Assist in preparing the anaesthetic for local anaesthesia
Be cognizant of all aseptic precautions and should prevent accidental contamination
Should know all vitreo-retinal instruments
Should know how to put on the indirect ophthalmoscope on the surgeon's head during surgery
Should know how to connect and disconnect endolaser, cryo machine, etc.
Must preferably have working knowledge of the vitrectomy console so that minor faults can be rectified without the need to call the biomedical engineer.
| III. INFRASTRUCTURE|| |
This subject can be broadly discussed under facilities for outpatient department and the operating room.
In addition to examination of presurgical and postoperative vitreo-retinal patients, medical retina is mostly practised on an outpatient basis. The outpatient department [Table - 1] should house the clinic (office) of the surgeon. This should be equipped with slitlamp and binocular indirect ophthalmoscope. In addition to the routinely used +20D condensing lens, +90D (yolk) lens is very useful for examination of macula, disc, and vitreous cavity. The slit-lamp should have an applanation tonometric attachment. Facility should be available to perform simple procedures such as OPD fluid-air exchange [Table - 2].
The OPD should also house a fluorescein angiography unit [Table - 3], an ultrasonography unit [Table - 4], and electrodiagnostic workup services. Of these, fluorescein angiography and ultrasonography are a must for a good vitreo-retinal unit. Depending upon the patient volume, fluorescein angiography can be performed either by an ophthalmologist or by a trained technician. Laser photocoagulation [Table - 5] is the commonest mode of treatment employed in the treatment of vitreo-retinal diseases. In an institute-based unit, it is best to have separate laser machines for outpatient department and intraoperative use. In a situation where the patient volume is low, it may be more practical to have a single unit that caters to slitlamp delivery, indirect ophthalmoscopic delivery, and endolaser delivery. To reduce the shifting of the machine to a minimum under such circumstances, one may have to house the laser close to the operating rooms.
It is preferable to have an operating room (OR) dedicated for vitreo-retinal surgery wherever feasible. In view of the wide array of instruments that are needed, the space required in the OR is more than that required for anterior segment surgery. Facility for general anaesthesia must be available. There are various ways in which the instruments can be arranged around the patient. No method can claim to be perfect. A model of one such arrangement is shown in the illustration.
Each operating room for vitreo-retinal surgery must be self-contained with minimum need for instruments from another operating room. The essential major instruments are listed in [Table - 6].
It is preferable to have a stand-by vitrectomy console to avoid getting stranded halfway through the surgery. One can use them alternately as a routine. A separate operating room for infected cases is desirable.
The basic set of surgical instruments are packed in a tray earmarked for a particular case. This allows customization depending on the case and the surgeon.
However, the tray which is autoclaved contains only the basic set of instruments. The instruments in a typical vitreo-retinal tray are listed in [Table - 7].
The rest of the vitreo-retinal instruments [Table - 8] are usually packed individually and sterilized by ethylene oxide. These are kept in the OR for use when needed. Instruments such as vitreous forceps, vitreous scissors, etc., may not be needed in all vitreo-retinal cases. Hence, packing them with the basic tray entails unnecessary resterilization of the instruments, thereby increasing their wear and tear. The list of consumables needed is given in [Table - 9].
| IV. CARE OF INSTRUMENTS|| |
Instruments such as vitreous forceps, scissors, etc., should be handled with care. The tip should be cleaned immediately after use to prevent blood and tissue from clogging the lever mechanism. Between actual use, the tips must be protected with safety guards. At the conclusion of each surgery, these instruments should be dismantled and flushed with distilled water followed by alcohol, using the adaptors provided by the manufacturers. Reusable vitreous cutters should be cleaned immediately after surgery by sucking at least 50 ml of distilled water (not saline) through it. Fibre optic cables should not be allowed to bend or get kinked. Expensive and delicate instruments should preferably be handled by only one or two persons during the packing and sterilization process.
To the extent possible, the instruments should be set apart for infected cases. Immediately after having been used for an infected case, the instruments should be cleaned and sterilized twice, before reuse.
| V. STERILIZATION|| |
Maintenance of absolute asepsis is very important in vitreo-retinal surgery. Many factors listed below predispose these patients to infection, viz.
Most of these patients are diabetics.
The surgery is expected to last long (2 to 4 hours).
There is a flow of large quantities of fluid through and out of the eye.
Most of the surgery is done with OR lights switched off.
Fibre optic cables and tubings can potentially spring up and touch the microscope.
In view of the above factors, the surgeon and the OR staff should be alert to the possibility of contamination. The following points are helpful in this regard:
Usage of surgical gloves is an absolute prerequisite.
Draping system using adhesive plastic surgical drape around the eye allows drainage of fluid without wetting the cloth drapes underneath.
The fibre optic cables and tubing should be anchored to the drapes at strategic points to prevent them from jumping.
Since ophthalmoscopic examination may have to be done frequently in between vitreous surgery, a system must be followed to avoid contamination while adjusting the same. Use of spectacle mounted ophthalmoscope is very useful since the adjustments can be adequately made by the OR assistant. If head band ophthalmoscope is used, the surgeon would have to adjust the ophthalmoscope personally. One can use sterilized long polythene bags over the gloved hands, adjust the ophthalmoscope and let the OR assistants remove them after the adjustment is completed.
Silicone oil should be autoclaved and used.
Gases can be drawn through 2 millipore filters in Tandem and used.
Liquid perfluoro carbon can also be drawn through 2 millipore filters in Tandem and used.
Sterile cryo probes should be used for each case. Storing a cryo probe between sterile towels and reusing it for the next case is an unacceptable practice.
The operating room should have an autoclave unit - preferably a high speed one to enable rapid sterilization of instruments that might have become contaminated accidentally during surgery. An ethylene oxide gas sterilizer is an absolute necessity. (See elsewhere for instruments to be sterilized). An ultrasonic cleaner is needed to clean instruments such as vitreous scissors, forceps, etc.
| VI. DESIGN FOR PATIENT COMFORT|| |
Patients undergoing vitreo-retinal surgery are also likely to suffer from diabetes, hypertension, and other related systemic diseases. Hence, a stand-by anaesthesiologist is preferred even for cases done under local anaesthesia. Intravenous line with venflon is mandatory. Oxygen should be delivered to the vicinity of the patient's nose to avoid suffocation under the drapes. The adhesive drape pasted around the eye helps to drain the irrigating fluid away from the patient's head into the gutter made by the drape from which it is intermittently sucked out. This ensures that the fluid does not trickle down onto the patient's face and ears. In view of the systemic diseases mentioned above, facility to perform rapid blood sugar estimation such as Reflolux should be available in the OR. Electrocardiogram and pulse monitoring is mandatory. An intensive care unit to take care of the immediate postoperative period is highly desirable keeping in view the high incidence of systemic diseases among vitreo-retinal patients.
| VII. SUPPORT SERVICES|| |
Diabetics form a significant percentage of vitreoretinal patients who may require surgery. In addition, they may suffer from other systemic disorders such as hypertension. An internist should be available to control their systemic problems before, during, and after the surgery. It is a good practice to have every patient scheduled for surgery to go through physician's examination in addition to routine laboratory tests for fitness.
In addition to routine laboratory services that are needed in any hospital set up, microbiology services should be available for a vitreo-retinal unit. The decision to inject a specific antibiotic is taken based on KOH and Gram's stain examination of vitreous aspirate during vitrectomy for endophthalmitis. Hence, this report must be communicated to the surgeon during surgery itself.
In view of the sophisticated array of instruments and dependence on them, the support of a biomedical engineer is invaluable. The biomedical department should have adequate stocks of spare bulbs for the operating microscope, endo illuminator, fluorescein camera, etc. The biomedical engineer should be able to repair instruments that go out of order on a minor scale, thereby keeping the need for service calls to a bare minimum. Moreover, valuable time is saved and the instruments do not lie idle while waiting for service engineers.
| VIII. BUDGET|| |
A brief outline of standard requirements and budgetary considerations is given below. The specifications mentioned are approximate and are near ideal for one vitreo-retinal surgeon.
Two operating rooms with adjacent 1,500 sterilization room, surgeons'room, etc.
10 single patient rooms with attached bathrooms 2,300
1 patient waiting room 300
2 examination rooms 600
Miscellaneous - administrative office, 2,000 drug store, stores, nurses'room, etc.
Cost of construction is expected to be Rs.800 to 1,000 per sq.ft.
Operating Microscope 32.00 4.00 with X-Y coupling x 2 (without X-Y coupling)
Vitrectomy consoles 24.00 4.00
(system) x 2
Laser equipment (1) 20.00 -
Cryo units (2) with probes 11.00 0.18
Slit-lamp with applanation 4.00 1.20
tonometer x 2
Indirect Ophthalmoscopes x 3 1.00 0.21
Sterilizers for 0 R and other 4.00 -
Microsurgical equipment 3.00 -
OPD - Other instruments 1.00 -
Office equipment 5.00 -
[Figure - 1], [Figure - 2]
[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7], [Table - 8], [Table - 9]