Woodcutter technique splits hard nuclei effectively

Unlike other methods, the phaco tip moves toward the chopper, which is fixed in the nucleus at the edge of the capsulorrhexis.

ByMichela Cimberle

ROME – A new technique of nucleus cracking that effectively deals with hard nuclei, saves phaco time and reduces stress on the zonules was presented at Rome 2001 by Vikas Mahatme, MD, of Nagpur, India.

“Have you ever observed a woodcutter at his work?” asked Dr. Mahatme. “When he wants to divide a wooden log into two vertical pieces, he nails a chisel at a point. Then he starts hammering the log with the axe some distance away from the chisel. He continues to hammer in the direction of the chisel, and the moment he’s approaching it, the log suddenly breaks into two vertical pieces. The cleavage extends beyond the chisel and penetrates deeper in the wood. I have used the same principle to divide the nucleus.”



The Woodcutter technique mimics a woodcutter at work in order to divide the nucleus. When a woodcutter wants to divide a wooden log into two vertical pieces, he nails a chisel at a point. Then he starts hammering the log with the axe some distance away from the chisel. He continues to hammer in the direction of the chisel, and the moment he’s approaching it, the log suddenly breaks into two vertical pieces. The cleavage extends beyond the chisel and penetrates deeper in the wood.

The axe and the chisel

In the traditional chop technique, the phaco tip holds the nucleus, while the chopper is placed at the capsulorrhexis margin and moved toward the tip. In the woodcutter technique, the action is reversed.

The chopper, which acts like a chisel, is fixed in the nucleus at the edge of the capsulorrhexis. The phaco tip is embedded in the center of the nucleus, and with phaco on, is pushed toward the chopper, acting like the woodcutter’s axe.

“As the phaco tip approaches the chopper, the nucleus splits. The cracking extends beyond the chopper toward the periphery and deep inside the nucleus, until it reaches the soft cortical matter. If you want to divide the nucleus further, you can use the same technique on the single segments,” Dr. Mahatme said.

The woodcutter technique requires no previous sculpting or grooving and is especially effective on hard nuclei.

“The advantage is that they split in just one stroke, and this significantly reduces phaco time,” he said.

Tips for woodcutters

Fig. 2b
In the traditional chop technique (top), the phaco tip holds the nucleus, while the chopper is placed at the capsulorrhexis margin and moved toward the tip. In the woodcutter technique (bottom), the action is reversed.

Dr. Mahatme explained that the sleeve of the phaco tip should be pulled back, so as to expose a 1.5- to 2-mm area. He pointed out that hard nuclei require more exposure of phaco tip.

Then the phaco tip is introduced into the anterior chamber. Through a side port incision, the chopper is also introduced into the anterior chamber.

“With the help of the chopper, the nucleus is pushed about 1 mm away in the direction opposite to the incision site, and the phaco tip is embedded in the nucleus at an angle of 70° to 80°,” he said.

He recommended a clear corneal incision rather than a scleral one, as it would be difficult to hold the phaco tip almost vertically through a scleral tunnel.

“Then, the chopper is buried at the capsulorrhexis edge. With the phaco on, the tip is moved toward the chopper, and that’s all – your nucleus splits like a log under the axe!”

Safe and effective

According to Dr. Mahatme, the woodcutter technique is very safe. There is no risk of disrupting the posterior capsule, as you are working away from it on a safe zone, which allows you to remain clear of the posterior capsule.

It is also simple, and beginning surgeons can directly adopt it without learning routine chop technique.

“[The] woodcutter doesn’t require a long learning curve, although at first you may not achieve the result of splitting the nucleus in one stroke. But this is not a real problem. Just rotate the nucleus, and start again. Most surgeons are able to perfectly master the technique after performing it five to 10 times,” he said.

In a study, Dr. Mahatme compared phaco time, cleavage time and number of strokes in cataract patients treated with routine chop technique and woodcutter technique.

“The values were significantly lower with woodcutter, and the difference was statistically significant (P<.001),” he said.

For Your Information:

Vikas Mahatme, MD, can be reached at the Mahatme Eye Bank & Eye Hospital, 16 Central Excise Colony, Ring Road, Nagpur 440015, India; (91) 712-234345, 712-222556 or 712-223050; fax: (91) 712-226189; e-mail: vikasmahatme@rediffmail.com or vikas_mahatme@yahoo.com; Web site: www.mahatmehospital.com.

Rome 2001, the Rome Symposium on Cataract, Glaucoma and Refractive Surgery, was co-sponsored by Ocular Surgery News Europe/Asia-Pacific Edition, The Italian Association of Cataract and Refractive Surgery and the International Society of Refractive Surgery. For information on future meetings, contact Meeting Registration at (856) 848-1000.