Positioning for surgical patients who cannot lie flat
Many older patients are unable to lie flat on their back for eye surgery in the supine position. In fact, if given the choice, most patients would prefer to sit up a little for cataract surgery. For patients who are truly unable to lie flat, the following options are available:
Patient has bent spine/neck, otherwise well: Trendelenburg position
Typical examples would be anklyosing spondylitis or other problems causing a kyphosis of the spine. If the patient is able, they can be positioned in a chair which is then tipped backward, so that the patient's feet are above their head. This is called the 'Trendelenburg position'. It only works for patients who can tolerate this position therefore it is not suitable for many older patients who may have coexistent orthopnoea. It is a useful option for surgeons who do not have access to a microscope that rotates forward (see option 3). Because the head is lower than the rest of the body, venous engorgement can be expected, This may cause vitreous bulge: for cataract surgery, this can be compensated for by raising the height of the infusion bottle.
Many types of surgical chair will tip back to the Trendelenburg position.
Patient cannot have chest flat, but has flexible neck: Patient seated upright, surgeon standing
Typical examples would be the patient with orthopnoea (e.g heart failure or severe COPD), but has a flexible spine so they can extend the neck. If severe orthopnoea, the patient may need to be seated upright. The head-rest is adjusted so that the patient can extend the neck, and look up to the overhead microscope. A surgeon of average height will find that they cannot comfortably operate from the seated position, and it is much easier for the surgeon to stand. Usually this means a 'standing temporal' approach, though this is not always necessary. Generally speaking, this is not as difficult as it sounds, though some surgeons may find that they are not suited to the technique.
Many types of surgical chair will allow this position.
Patient cannot have chest flat, and cannot extend neck: Face-to-face upright seated positioning
This is actually the commonest reason for an inability to position supine: a combination of problem 1 and problem 2. For face-to-face surgery, the patient sits upright and comfortable on the surgical chair. The microscope is rotated forwards to face the eye, and the surgeon sits (or stands) facing the patient. Cataract surgery is done through an incision in the lower half of the cornea: right-handed surgeons may find it easiest to use a temporal incision (0 degrees) for a left eye and inferior incision (270 degrees) for a right eye. Because the eye is higher above the floor than normal, the infusion bottle height should be raised accordingly.
Face-to-face positioning is easier if the patient can be a bit more supine, or extend their neck a little, or turn their face/chin-up toward the microscope. Sometimes it may help to rotate the whole patient so they are facing toward the surgeon. It's worth spending time to ensure that patient and surgeon should remain comfortable for what may be a longish operation. Topical (topical-intracameral) anesthesia means that the patient can direct their gaze toward the microscope, thus keeping the eye 'on axis' for easier cataract surgery. This principle is particularly useful for face-to-face surgery.
Many types of surgical chair will allow this position, and it can sometimes be used to operate on patients who cannot transfer from their wheelchair. It is necessary to have a microscope that can be rotated forward, so it faces more horizontally than vertically. For most face-to-face patients, the microscope will need to be 40-60 degrees away from vertical. For some microscopes, a rotation by this amount will mean that the surgeon's arms are uncomfortably high or too far outstretched: this can usually be overcome by using short eyepieces that can be rotated upward.
Surgeons wishing to try face-to-face surgery should be already experienced in cataract surgery with topical anesthesia. The patient chair should be adaptable to various positions. The microscope should be able to rotate forward. It may be necessary to purchase some new eyepieces (short, can be rotated upwards through a large range). Shortening the microscope can also help to make it more comfortable for the surgeon: many microscopes may have camera sections or other attachments- if these can be safely removed, it can make surgery easier (and therefore quicker and safer).
Patients who cannot lie flat for cataract surgery should be warned that their surgery may have a higher risk of surgical complications.
- Lee RM, Jehle T, Eke T. Face-to-face upright seated positioning for cataract surgery in patients who cannot lie flat. J Cataract Refract Surg. 2011 37(5):805-9