FINGER EXERCISES WITH ANATOMICAL CONSTRAINTS - RePub

304 Pages·2010·9.81 MB·English

FINGER EXERCISES WITH ANATOMICAL CONSTRAINTS
A METHODOLOGICAL ANALYSIS OF NON-PATHOLOGICAL
ANATOMICAL VARIATIONS AS CAUSES OF HAND PROBLEMS IN
MUSICIANS
VINGEROEFENINGEN MET ANATOMISCHE BEPERKINGEN
EEN METHODOLOGISCHE ANALYSE VAN NIET-PATHOLOGISCHE
ANATOMISCHE VARIATIES ALS OORZAKEN VAN HANDPROBLEMEN BIJ
DE MUSICUS
PROEFSCHRIFT
Ter verkrijging van de graad van Doctor aan de Erasmus Universiteit Rotterdam
op gezag van de Rector Magnificus Prof.Dr. P.W.C Akkermans M.A.,
en volgens het besluit van het College voor Promoties.
De openbare verdediging zal plaatsvinden op
woensdag 6 december 1995 om 13.45 uur.
door
Joris Nicolaas Anna Leon LEIJNSE
Geboren te Aalst, Belgie
Promotiecommissie:
Promotoren:
Prof.Dr.Ir. C.J. Snijders
Prof. Dr. J .C.H. van der Meulen
Leden:
Prof.Dr.!r. J.J. Kalker
Prof.Dr. J. Voogd
Dr. S.E.R. Hovills
To my parents, who created me,
to my surgeon, Dr. Bonte, who recreated me,
to Prof. van der Meulen, who put me on tenure track,
to my PC, without which this could not have been written.
Printed by Optima Dmk, Molenaarsgraaf, The Netherlands.
CONTENTS
PREFACE
INTRODUCTION
CHAPTER I KINEMATIC MODELS
(i) Biomechanics of the finger with anatomical restrictions - the significance fur the exercising
hand of the musician
J.N.A.L. LeljiJse, J.E. BOllle, 1.M.F. Lalldsmeel', 1.J. Ka/ker, 1. C. mil del' Meulell, C.l. SlIijders
(ii) The hand of the musician: the kinematics of the bidigital finger system with anatomical
restrictions
J.N.A.L. Leijllse, C.J. Snijders, J.E. Bome, 1.M.F. Lalldsmeer, J.J. Kalker, J.C. vall der Melliell,
G.}. SOllllet'eld, S.E.R. HOl'ills
(iii) A two dimensional kinematic model of the lumbrical in the human fmger
J.N.A.L. Leijllse, alld J.1. KalkeI'
CHAPTER II FORCE MODELS AND INDETERMINATE PROBLEMS
(i) A graphic analysis of the biomechanics of the massless bi-articular chain
J.N.A.L. Leijl/se
(ii) The controllability of the unloaded finger with superficial or deep flexor
J.N.A.L. Leijllse
(iii) Why the lumbrical muscle should not be bigger - a force model of the lumbrical muscle
in the unloaded human finger
J.N.A.L. Leijllse
CHAPTER III MEASURING FORCE TRANSFERS IN THE M. FLEXOR
DIGITORUM PROFUNDUS
(i) Measuring force transfers in the deep flexors of the musician's hand - theoretical analysis,
clinical examples
J. N.A.L. Leijllse
(Ii) Measuring force transfers in the deep flexors of the musician's hand - device and
systematic measuring errors
J. N. A.L. Lei,jllse
CHAPTER IV ANATOMIC FACTORS PREDISPOSING TO FOCAL DYSTONIA IN
THE MUSICIAN'S HAND
Anatomic factors predisposing to focal dystonia in the musician's hand
J.N.A.L. Leijllse
CHAPTER V MODELS OF MUSCLES AND APONEUROSES
(i) A generic model of a muscle group - application to the muscles of the forearm
J. N.A.L. Leijllse
(Ii) The morphology of holes in aponeuroses caused by perforating nerves or vessels at the
medial epicondyle of the elbow
J. N.A .L. Leijllse
CHAPTER VI MODELLING THE MORPHOWGY OF ANATOMICAL
INTERCONNECTIONS IN THE M. FLEXOR DIGITORUM PROFUNDUS
(i) Anatomical interconnections within the M. flexor digitorum profundus - the significance
for the hand of the musician
J.N.A.L. Leijnse, E.T. Walbeehm, G.J. SOlllleveld, S.E.R. Rovills
(ii) Connections between the tendons of the M. flexor digitorum profundus formed by the
synovial sheaths in the carpal tunnel
J.N.A.L. Leljl/se, E. T. Walbeehw, OJ. Somleveld, S.E.R. Hovius, J.M. G. Kauer
(iii) A generic model of the anatomic variability in the M. flexor digitorum profundus, M.
flexor pollicis longus, and Mm. lumbricales complex -the significance for the musician
l.N.A.L. LeijJlse
CHAPTER VII SURGICAL CLEARANCE OF INTERTENDINOUS CONNECTIONS
A CASE STUDY
Total surgical clearance of intertendinous connections in a musician's hands, including
cleavage of bitendinous lumbrical origins - a case study
J. N.A.L. Leljl/se, and J.E. Hollte
CHAPTER VIII SUMMARY AND CONCLUSIONS
Samenvatting en conclusies
ACKNOWLEDGEMENTS
CURRICULUM VITAE
PREFACE
Consider a group of men, selected from many for their exceptional ability to hammer tiny nails in
regular arrays in endless walls. Assume their future will be to daily hammer a fixed number of
such nails into artistic patterns, to the amusement of a public which esteems this greatly. At the
onset of this task each receives a small hammer of superb quality, which, like a fountain pen, is
never to be held by others. All hanuners look alike exactly, but there is a snag: one is made from
outlandish material more than five times as heavy as the normal steel. Day by day the men
hanuner away producing great events, but as time proceeds the man with the heavy hammer
becomes a little tired and sometimes hits the little nails not quite on their little head. Moreover, as
more nails are wrongly hit, more time is spent hitting them rightly. Others notice, and give advice
in sympathy, but eventually he is a liability and hammers alone. Then the pain starts, his hand
starts shaking, he tries strange hammering positions in despair, on a ladder bent over upside
down, but hammering becomes ever so difficult and finally impossible. He seeks professional
help. Someone looks at him and says: your back is crooked, your posture bad. So they work until
he is erecter than the homo erectus ever was, but hammering remains a problem. Then electrodes
reveal unexpected muscle activity, and he learns to relax until he is a jelly pudding, but the
hammer still trembles. Then someone gets smart and says: there is an antagonistic disbalance, and
fills him up with botulinum toxin (type A). Now he cannot hammer, but for good cause: his
muscles are paralysed. However, the pain disappears, and when he finally hammers again, at first
all goes well, until the problem returns. And so it goes on, and on, and on. Clearly, this man is
doomed, and will never hammer again, unless given a normal hammer. Moreover, barring
meanwhile permanent damage, the mere exchange of hammers will make this man a normal
hammerman. The basic question, however, remains: how does one find out the weight of this
hammer - when the man never gives it to you to weigh?
This imaginary set-up describes an overuse situation, as conceived in the present thesis.
The variables may be changed: our hapless hanunerman may be a musician, the weight of his
hammer a mysterious property in his hand, and the name of his complaint "focal dystonia".
However, the structure of the situation remains. It is, by present hypothesis, a complaint in which
nothing is basically wrong with anything, except that the constellation of the factors leads to
conflict. The example clearly outlines the possible cures: diminishing hanunering time may
resolve the clinical complaint, but perhaps performance may remain dissatisfactory; different
posture and technique may lead to better results, but when the hammer is too heavy they will not
resolve the problem, while changing the hammer resolves the conflict forever. For proper
diagnosis, the hammer's weight must be quantified, for other causes may produce similar
symptoms. This then is the aim of the present thesis: to quantify why hands to one musician may
be almost weightless, and to another may be more than he can pull.
INTRODUCTION
IlIIroductiofl
INTRODUCTION
Recently, hand problems in musIcIans have been recognised as systematic events. Numerous
papers and statistics have been published (see Chapter IV); even, a journal eXclusively devoted to
such and similar problems in performing artists exists!. The present thesis defends the hypothesis
that many hand complaints, such as focal dystonia, are caused by non-pathological anatomical
variations in the hand. It is good habit to introduce such thesis by profiling it against the historic
and current state of affairs. Instead, however, I would like to present an account of the events
which led to this thesis, which is, to a degree, an autobiography.
A short auto-biography
I started as a violin player, studying at a special high school for musicians, and subsequently at
the conservatory of Brussels (1974-1976). There, I soon developed hand coordination problems
which terminated this career. With some talent to burn, I studied graphic arts. However, in the
process of long hours of drawing and engraving, I gradually lost the very fine motor control
required for high quality work, and quit this career with hands feeling like wood. Unabashed, I
took a prep year of mathematics and subsequently studied civil engineering with a major in
applied mathematics, only soon to develop problems with hand-writing. As the formulas grew
longer, handwriting grew worse, and a third career became jeopardised by basically the same
problem. The regular route for professional help of the overuse patient is the general physician,
the music therapist, the hand surgeon, the neurologist, or the alternative medicine man, or all of
them in some order ([ubiana, 1993). Some cases respond to therapy, but many remain
untreatable, and patients will seek help until they run out of advise, money or motivation. I took a
different route. In art school I studied the musculo-skeletal system from the medicine courses.
There I found a little remark on the effect of the juncturae tendinum on extensor independence.
These jucturae were exceptionally developed in my hands, as could be verified by superficial
observation. The removal of the connections took some effort, because at first, and despite
vigorous mobilisation they tended to regenerate. Although the effect was beneficial, it turned out
that many other extremely strong intertendinous connections were present. I became expert in
localising them by hand tests, my surgeon in removing them. The left hand, which was treated for
violinistic reasons, was used as a model for the right hand, where the later writing problem was
treated. During the period of 1979-1988, all connections between all finger tendons were
systematically removed in both hands: between the extensors, between the superficial flexors,
between the deep flexors, and between the lumbricals. Collateral damage was caused to the flexor
retinacula which resulted in thumb weakness in both hands; this was resolved to a large degree by
the reconstruction of the ligaments (1989). The final result was a new pair of hands, with
enormously improved dexterity and tactile abilities, without loss of basic strength except for the
thumbs. The original hand coordination problems had completely disappeared. Although I can
now easily type at great speed, I never returned to the violin, for the reasons given in Chapter
VII, which presents the case-study. Considering the novelty of these surgical procedures and their
introduction
number, this relative success is a miracle in itself, in which good surgery and my mobilisation
efforts were at par. In 1989 I had a memorable meeting with prof. Landsmeer, and with his
support applied for a research position at the Dept. of Hand Surgery at the Erasmus University of
Rotterdam. Such a position was created by Prof. van der Meulen, head of the department, with
the valuable support of prof. Snijders, head of the Dept. of Biomedical Technology (1990).
The methods of the present thesis
The above history motivates the approach taken in present thesis. Most noticeable is the almost
total lack of experimental data. The quantification of the surgical model assumptions by e.g.
comparing normal and diseased hands would have required massive equipment and organisation,
for which there was no allocated money. Therefore, I chose to minimise measuring attempts, and
to present the therapeutic models as clearly as possible for further validation by the scientific
community. As a result, the present thesis is foremost a study of method; I.e. the theoretical proof
that anatomical variations are important and may harm hand function. Nevertheless, a measuring
device was built to quantify the force transfers between the deep flexors. This instrument now
serves for diagnosis and prognosis of clearance of anatomical connections in this muscle group.
The thesis analyses the effects of anatomic intertendinous connections at different levels. In
Chapter I, the kinematics of fingers with intertendinous connections are addressed. In Chapter II,
the indeterminates in finger motor function in the unconstrained normal finger are analysed. In
Chapter III, the force transfers within the deep flexors are modelled, and validated by means of
mentioned measuring device, and the systematic problems with these measurements are discussed.
In Chapter IV, the muscle load increases due to intermuscular force transfers are discussed, both
generally, and by means of a simple example of pianist's hand with a comlection between the long
thumb flexor and the deep flexor of the index. By way of examples a number of important
biomechanical elements which concern diagnosis are illustrated. An anatomic section is included.
This discusses as a general introduction a basic muscle model used throughout this text (Chapter
V), and further models the systematic anatomical variations in the deep flexor group (Chapter VI).
Lastly, the post-op results of the surgery in my own hands are presented.
The kinematic finger model
The choice of a model is an important research decision. Given the complexity of the subject
matter, the model had to be as simple as possible, yet comprehensive. This simplicity was found
in Landsmeer's models, in the formulation of Spoor and Landsmeer (1976). However, this paper
describes model elements, rather than a holistic model. Moreover, in some finger movements
tendon parts become slack, a property I found difficult to implement into a general formulation.
This problem was solved by Prof.Dr.1r J.J. Kalker, from the Delft University of Technology.
Prof. Kalker is a tribologist, who normally solves problems of friction and vibrations in wheels of
trains. Contact forces and muscle forces share the property of being unidirectional, and with his
vast experience with such systems prof. Kalker effortlessly wrote out a general concept
incorporating the tendon slacks (Kalker, 1990). However, he formulated it in terms of
inequalities, which are mathematically tedious. This I resolved by quantifying the tendon slack by
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Introduction
non-negative slack variables, as are used in linear programming to reduce inequality constraints to
equalities. The result was the simple, comprehensive model of Chapter I.i, in which the lumbrical
was implemented in Chapter I. iii, and which is used for calculations throughout the text. In
practical terms, the slack variables proved their usefulness by allowing concise indications of the
different states of model functioning. In the text models moment arms are assumed constant,
except for the lateral slips of the extensor assembly at the PIP joint. Yet, in other models
considerable effort is made of implementing the relatively small changes of the other motor
moment arms with joint rotations. For the present applications this additional complexity seemed
useless, besides, it would distract the attention from the systemically important PIP-DIP coupling
mechanism resulting from the shifting of the lateral slips of the extensor assembly at the PIP.
Cracking the Landsmeer model
In 1955, Landsmeer provided a displacement model to explain the mechanisms of claw and swan
neck formation. Although recognised as a fundamental contribution, it was perceived as somewhat
enigmatic and remained basically unchanged for the past fourty years. When tackling the problem
of flexor redundancy and finger control (Chapter 6), which to my intuition is basic to the deeper
understanding of hand function in the musician, I started from the Landsmeer model, but soon
became entangled in certain particularities of its original formulation. These I could not resolve in
the original displacement model, but they proved well treatable in the equivalent force model.
This resulted in the general formulation of the statics of the bi-articular chain in Chapter II.i,
which confirms Landsmeer's model principles while making them more accessible. Anecdotically,
this paper has the extra dimension of an expected publication exactly fourthy years after
Landsmeer's, while it was born accompagnied by his encouragements.
A clinic for musicians
Over the past decades, a consultive cooperation developed between a music therapist, Mr. van de
Klashorst and Prof. van der Meulen, who, with his successor, Dr. Hovius, contemplated the
establishment of a proper clinic for musicians. The present study provided a theoretical
background for surgical treatment of otherwise hopeless cases. The clinic took a definite form
when Dr. Sonneveld took charge. Musicians are not the usual patients and they require a
physician with both skill and patience. Today, a few musicians have already been surgically
treated, and all have resumed their activities, even reporting improved technical abilities.
'Medical problems of performing artists. Hanley and Belfus, Inc., Medical publishers,
Philadelphia
Tubiana R., (1993) The Hand, pp. 873-885, W.B. Saunders Company.
KalkeI', J.J. (1990) An inequality calculus for the tendons of the hand. Private communication.
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