• The online Community for people with spinal cord injury, their relatives and friends

  • The online Community for people with spinal cord injury, their relatives and friends

  • The online Community for people with spinal cord injury, their relatives and friends

  • The online Community for people with spinal cord injury, their relatives and friends

  • The online Community for people with spinal cord injury, their relatives and friends

Intrinsic hand muscle function, part 2

Comparing two surgical procedures used to restore a functional grasping movement

Author of summary: Ursina Arnet (Swiss Paraplegic Research)
Original article: Muzykewicz DA, Arnet U, Lieber RL, Friden J. Intrinsic hand muscle function, part 2: kinematic comparison of 2 reconstructive procedures. The Journal of Hand Surgery (American Volume). 2013;38(11),2100-5.e1.

In order to achieve a natural and functional grasp, in addition to rebuilding the motion of finger flexion through a tendon transfer, functioning of the intrinsic muscles should be restored as well. For this purpose the House surgical procedure is preferable to the Zancolli lasso procedure.

What was the aim of this study?

The wish for regaining their hand function ranks first for most tetraplegics. By performing a tendon transfer, it is possible to restore certain finger functions. The ability to flex the fingers, for example, can be recovered through a transfer of the tendon of the extensor carpi radialis longus (muscle that stretches the wrist) to the tendon of the flexor digitorum profundus (muscle that flexes index to little finger).

A previous study has shown that when restoring the finger flexion also the so-called intrinsic muscles should be included to regain an optimal and functional grasping movement (see article in the Research Corner "Intrinsic hand muscle function, part 1: creating a functional grasp"). The small muscles are located in the palm of the hand and are attached laterally on each of the four fingers (index to little finger). When the intrinsic muscles are active, the distance between fingertip and palm is bigger while doing the grasping movement. Therefore also larger objects can be clasped.

There are two different operation procedures to restore the functioning of these muscles surgically: the Zancolli lasso procedure and the House procedure. The aim of this study was to find out which of the two procedures enables a more functional and natural grasping movement.

How did the researchers proceed?

Twelve hands were examined that were donated by deceased persons. An experienced tetraplegia hand surgeon operated on six of the hands following the Zancolli lasso procedure and on the other six hands following the House procedure.

In order to simulate the grasping movement, the tendons of the finger flexor muscles were then connected to a motor. The motor was set in a way that the stretched fingers of the open hand contracted to form a fist. The scientists recorded a video of the finger movement. From the video the angles of the individual finger joints, the sequence of the joint movement and the distance between fingertip and palm during the movement was calculated. The data from the hands with the two different surgical methods was then compared.

What did the researchers discover?

Both surgical methods showed as a result that the distance between fingertip and palm during the grasping movement was bigger than without a surgery. The reasons for this improvement, however, were different.

With the Zancolli lasso procedure (see figure 1) the tendons of the finger flexor muscles on the surface are shortened so that the fingers are always slightly flexed in the metacarpophalangeal joint (joint that connects the fingers to the palm). This changed the initial position of the grasping movement for the study and therefore the distance between fingertip and palm during the gripping.

Figure 1: Zancolli lasso procedure (shortening of the finger flexor tendons)

The House procedure (see figure 2) uses a tendon graft, i.e. a finger tendon from a paralyzed finger flexor muscle of the same body is implanted. With the tendon graft the index finger joint in the middle is connected to the one of the middle finger. The same is done with a second tendon graft at the proximal interphalangeal joints of the ring and the little finger.

According to the study, through this firm connection the movement pattern changed during the grasping movement: first the fingers were flexing in the metacarpophalangeal joint and only then in the proximal and distal interphalangeal joints. This corresponds with a natural grasping movement and enlarges the distance between fingertip and palm during the grasping movement.

Figure 2: House procedure (implanted tendon graft)

What do these findings mean?

The results of this study show that both surgical procedures do improve the functioning of gripping: by restoring the function of the intrinsic muscles, the distance between fingertip and palm is enlarged during the grasping movement. This allows for bigger objects to be grasped.

Comparing the two surgical procedures shows, however, that only the House procedure can restore the "natural" movement pattern which corresponds to a hand movement with active intrinsic muscles. When restoring the grasping movement surgically, the House procedure is therefore preferable to the Zancolli lasso procedure.

Who conducted and financed the study?

The study was carried out and financed by Swiss Paraplegic Research in Nottwil, Switzerland, and the Muscle Physiology Laboratory of the University of California in San Diego (USA).

Comments (0)

There are no comments on this topic yet.
Be the first to comment!

Rate this post

Most Recent Answers
5272 odyssita
Explaining what life with a chronic disability is like
Hi cAro, all the best for your research! I am very curious to hear about the results once they are being published. Thank you for researching this...
6 odyssita 2018-05-02
5189 Wheelie
Good news for all who would like to try out the Scewo by themselves: according the Scewo constructors, the feedback on their invention was so...
5 Johannes 2018-03-12
Ask the Expert
Most Recent Answers
3 Dr._Hans_old 2015-07-20
3 Dr._Hans_old 2015-05-07

Most Recent Blog Posts
Wheelchair chefs: the success stories
Disabilities matter but ambition rules
lorenzo.deluigi 2020-07-22 In News
Make to Care, a competition promoting innovations
Which one of these four innovative projects convinces you the most?
kitwan 2020-07-02 In Society
Wheelchair users’ game of thorns
The fight for personal space, safety and independence
Most Read
Anatomy and physiology of respiration
Breathing is the most normal thing in the world for us. We hardly think about it, even though we breathe in and out about 20,000 times per day. We breathe more when we are active and exerting ourselves, and we breathe less when we are...
Social skills increase quality of life
Today strawberry yogurt is on Anna’s* grocery list. In front of the dairy section she notices that she cannot reach the yogurt sitting in a wheelchair. Many stressed people are rushing through the crowded store during rush hour and she does not...
Mobilisation / Transferring
What do I need to consider with regard to the shoulders? The shoulder is the most heavily-strained joint with regard to mobilisation – that applies to sitting up and transferring. It is therefore important to protect the shoulders whenever it is...

About the Community
Most Recent Topics
2020-08-04 In Latest
An unconventional book on ignoring disability
"A picture is worth a thousand words." How about blank pages? Recently, a blank book has been released to express the absurdity people with disabilities are experiencing every day, as there is...
2020-07-16 In Latest
Free masks for high-risk patients with SCI
People with high-level tetraplegia, paraplegics of higher age and those with pre-existing health conditions are more susceptible to a severe development of COVID-19. For this reason, the European...
2020-07-03 In Latest
A COVID inspiration porn?
Over three months since the COVID-19 declared pandemic, many countries are still debating whether to make wearing face masks compulsory to help prevent the spread of the disease. Noam Gershony, an...


Swiss Paraplegic Research
Guido A. Zäch Strasse 4
6207 Nottwil

This email address is being protected from spambots. You need JavaScript enabled to view it.
T 0800 727 236 (from Switzerland, free of charge)
T +41 41 939 65 55 (from other countries, charges apply)

Be part of the Community – sign up now!