Re-enablement of the neurologically impaired hand – 1 ...

Lepr Rev (2006) 77, 317– 325

WORKSHOP REPORT

Re-enablement of the neurologically impaired
hand – 1: terminology, applied anatomy and
assessment. Report of a Surgical Workshop held
at Green Pastures Hospital and Rehabilitation
Centre, November 2004, Pokhara, Nepal

J. W. BRANDSMA* & R. J. SCHWARZ**,
ON BEHALF OF THE WORKSHOP PARTICIPANTS AND
REVIEWERS
*Formerly Consultant Rehabilitation, **formerly Surgeon and
Medical Superintendent, Green Pastures Hospital and Rehabilitation
Centre (GPH&RC)
*International Nepal Fellowship (INF), PO Box 28, Pokhara, Nepal

Accepted for publication 25 September 2006

Introduction

A workshop on the re-enablement of the neurologically impaired hand was held at Green
Pastures Hospital and Rehabilitation Centre, Pokhara, Nepal, with the following aims: (a) to
exchange ideas and techniques between experienced leprosy surgeons from different
countries and continents about assessment and surgical reconstruction of the primary and
secondary impairments of the neurologically impaired hand and (b) to develop a document
with best practice recommendations and areas for further research. A similar workshop was
organized in 2000 on the neurologically impaired foot. The proceedings of this workshop
have subsequently been published.1,2

For proper understanding of the primary and secondary impairments and their
assessment, it is mandatory that there is consensus about terminology and adequate
understanding of (patho) kinesiology of the hand. These will be discussed in the first part of
this report. The second part of the report will discuss surgical techniques as they relate to the
primary and secondary impairments.

Correspondence to: J. W. Brandsma (e-mail: [email protected])

Workshop participants/reviewers: P. Das, F. Duerksen, J. Joshua, M. R. C. Macdonald, G. N. Malaviya,
S. Murray, J. F. Negrini, A. Salafia, T. A. R. Schreuders

0305-7518//064053+09 $1.00 q Lepra 317

318 J. W. Brandsma & R. J. Schwarz

Terminology

In the International Classification of Functioning, Disability and Health (ICF, previously
ICIDH), impairments are defined as problems in body function or structure such as a significant
deviation or loss.3,4

An example of impairment in body function would be loss of sensation; examples of
impairments in body structure would be contractures and absorption. A ‘deformity’ would be
a structural, usually visible, impairment. Activity limitations (formerly ‘disabilities’) are
defined as ‘difficulties an individual may have in executing activities’. Examples in leprosy
patients would be difficulty in eating, dressing or writing because of impaired hand function.
‘Disability’ is now used as an umbrella term for impairments, activity limitations and
participation restrictions (formerly handicap). If a leprosy-affected person is prevented from
entering a teashop or riding the bus, then there is a participation restriction (Table 1).

Primary impairments are the immediate effects of peripheral nerve dysfunction, e.g. loss
of sweating, impaired sensation and weakness/paralysis. Secondary impairments are the,
often avoidable, impairments that may be a consequence of the primary impairments, ulcers,
absorption, contractures etc. Other, different, impairments may also follow reconstructive
surgery (see companion article).

The naming of a surgical procedure is often not sufficiently informative, e.g. Zancolli
Lasso operation. It is suggested that when naming a technique at least the donor muscle and
insertion should be mentioned, e.g. palmaris transfer with ‘lasso’ (pulley) insertion.

Prevention of primary impairments: early diagnosis of the disease and early/ adequate
treatment of ‘neuritis’

EARLY DIAGNOSIS OF THE DISEASE

It is generally accepted that an early diagnosis of the disease will prevent nerve function
impairment (NFI) in the majority of newly diagnosed cases. Nevertheless, NFI may
develop in newly diagnosed patients who reported without NFI and may increase even
more in patients who reported with NFI at the time of diagnosis.5,6 It is clear that
worldwide, fewer patients report with disability and nerve function impairment at the time
of diagnosis.7,8

NERVE SURGERY

Much has been written about techniques and the possible positive effects of nerve surgery. To
date there is no evidence from randomized clinical trials that nerve surgery may be beneficial

Table 1. Health related definitions3

Impairment Problems in body function or structure such as a significant deviation or loss
Activity Execution of a task or action by an individual
Activity limitation Difficulties an individual may have in executing activities
Participation Involvement in a life situation
Participation restrictions Problems an individual may experience in involvement in life situations
Functioning An umbrella term encompassing all body functions, activities and participation
Disability An umbrella term for impairments, activity limitations and participation

restriction

Re-enablement of the neurologically impaired hand – 1 319

in the prevention of NFI or in the recovery of nerve function.9 Amongst the workshop
participants, there was consensus that nerve surgery is indicated in case of nerve abscess and
when there is chronic pain in the nerve not responding to medical treatment including
corticosteroids.

Most leprosy workers would agree that an early diagnosis of the disease/impaired nerve
function and subsequent appropriate treatment enhances the chances for prevention of
permanent nerve damage.10 – 14 Whether nerve surgery would be of additional benefit when
NFI is present at the time of diagnosis is not known. There are also patients who in spite of
early diagnosis of NFI and timely instituted medical treatment do develop, or continue to
lose, nerve function. Whether surgery could have prevented this is also not known from
published literature. At a recent research workshop in Karigiri, India (2004), a protocol was
discussed to start a multi-centre randomized trial to assess the possible benefits of nerve
surgery in the prevention of nerve function impairment.

Biomechanics

A basic understanding of the biomechanics of the hand in relation to function and restoration
of function is mandatory. This should play an important role in selection of technique and
assessment and evaluation of outcome of surgery. For a brief review of basic hand anatomy,
especially the intrinsic muscles, the reader is referred to the literature.15– 18 Here we only
highlight some points that are of clinical relevance as it relates to the hand with paralysis of
the intrinsic muscles. The primary and secondary impairments that may be seen in the hand
with paralysis of the intrinsic muscles are given in Tables 2 and 3.

INTEROSSEI

The interossei are the key muscles in the stabilization of the finger joints in the sagittal
plane.19 The interossei could be considered the anti-clawing muscles of the hand. Their role
in metacarpo-phalangeal (MCP) flexion/ stabilization is more important for hand function
than their secondary role as abductors and adductors of the fingers.

The fingers that may not show clawing, usually the index and middle fingers, will usually
claw functionally when these fingers are active in grasping. This is often referred to as hidden
or latent clawing. This is easily revealed by asking the patient to grasp and squeeze the
examiner’s forearm. Increased pressure will be felt from the finger tips of the index and
middle fingers. The PIP joints will hyperflex and there will be limited flexion of the MCP
joints. This could be called Froment’s sign of the index/middle fingers. The biomechanical

Table 2. Primary impairments of ulnar nerve palsy

1. Loss of protective sensation and functional sensibility
2. Clawing due to loss of primary finger (MCP) flexors (interossei)
3. A-synchronour finger flexion-/extension.
4. Loss of ab- and adduction of fingers
5. Loss of metacarpal arch/ulnar opposition (hypothenar muscles)
6. Decreased grip strength
7. Decreased pinch strength (pulp-pulp and key-pinch)

320 J. W. Brandsma & R. J. Schwarz

Table 3. Secondary impairments of ulnar nerve palsy

1. Ulcers/Scars/Absorption
2. Contractures (PIP joints: skin/joint structures)
3. Long finger flexor tightness
4. Contracture oblique retinacular ligament
5. ‘Hooding’ / attenuation of extensor mechanism
6. Habitual wrist flexion
7. Z - Thumb

explanation for this is the same as Froment’s sign of the thumb: insufficient flexion moment
of the MCP joint. The fingers that lack interossei will have lost more than 90% of their MCP
flexion power and should be included in a tendon transfer to rebalance forces in the sagittal
plane.20 The lumbricals have minimal flexor moment on the MCP joints and their function is
mainly in unresisted opening and closing movements of the fingers depending on MCP
positions or movements.

MARTIN –GRUBER NERVE SHUNT

The presence of a Martin – Gruber anastomosis is often not recognized. This median to ulnar
nerve shunt can be assumed in an ulnar palsy when there is paralysis of the hypothenar
muscles in the presence of variable activity of the intrinsic muscles on the radial side of the
hand, notably flexor pollicis brevis and the first dorsal interosseus. In the presence of such
anastomosis in a combined ulnar and median palsy, there will be hypothenar paralysis and
wasting of the abductor pollicis, but activity is present in the flexor pollicis brevis and the first
dorsal interosseus.21 – 23 The presence of a Martin – Gruber anastomosis may result in less
clawing of index and middle fingers and a more stable thumb in pinch activities.

THUMB IN ULNAR NERVE PALSY

There is definite weakness of the thumb in pinching in an ulnar nerve palsy. Adductor pollicis,
flexor pollicis brevis, and first dorsal interosseus are all, or for the most part, ulnar innervated.
These muscles are all strongly active in pinch activities. Paralysis or weakness of these
muscles may show itself in Froment’s sign (IP flexion), and/or Jeanne’s sign (MCP
hyperextension). Whether these signs or other secondary impairments develop, such as MCP
instability and/or carpo-metacarpal (CMC) (sub) luxation, depends on such factors as hand
dominance and use, duration of the palsy, configuration of MCP joint surfaces and joint laxity.
These factors are also important to take into account when considering correction of the thumb
in ulnar nerve paralysis. The role and function of adductor pollicis and flexor pollicis brevis
in thumb stabilization could be compared with that of the intrinsics for the other fingers. They
have a flexor moment for the MCP joint and, through the lateral band, extend the IP joint.

GRIP STRENGTH AND LOSS OF METACARPAL ARCH

Little is known about the effect of ulnar or combined ulnar and median palsy on grip strength,
including pinch, nor is much known about the effect of surgical corrections for correction of
intrinsic paralysis on grip strength. Yet, often surgeons and therapists alike seem to take the
possible effect on grip strength into account when deciding on a surgical technique.24,25

Re-enablement of the neurologically impaired hand – 1 321

Antepulsion of the 4th and 5th rays at the CMC joints is a function of the hypothenar
muscles. This movement secures a power grip and contributes to grip strength. Brand named
the effect of the antepulsion of these rays, the ‘power house’ of the hand.26 Cupping of the
hand, which could also be named ulnar opposition, is very important in countries in which the
hand is used for eating and scooping water for drinking.

In leprosy, one study has explored the possible relationship between grip- and pinch
strength in activities of daily living.27 Another study has explored the possible relationship
between grip strength and type of tendon transfer.24

It should be noted, however, that grip strength per se does not seem to be the important
issue for most leprosy affected persons. Many will indicate (subjective) that grip strength has
improved following surgery while, objectively, with the use of a dynamometer, it can be
shown that grip strength has not changed or may have decreased. (Brandsma, unpublished
data). Because the hand has a more secure and better grip, this is often interpreted by the
patient as a stronger grip.

MOMENT ARMS/EXCURSIO /TENSION FRACTION

The surgeon needs to have a working knowledge of the properties of the muscles of the hand.
This is especially true for the ‘donor’ muscle(s) that will be used to substitute or enhance
functions that are lost or need to be reinforced. The important properties of muscles in the
context of tendon transfer surgery refer primarily to excursion potential and strength.
Knowledge of Brand’s work is indispensable.26 He calculated excursion and tension
generating potential for all of the forearm and hand muscles. More importantly, the surgeon
and therapist should also know about moment arms and how tendon rerouting and site of
insertion may affect hand function and outcome of surgery. For more detail the reader is
referred to the publications by Kozin, Fride´n and Lieber.28 – 30

ILEP guidelines for referral for surgery

In 1999 the Medico-Social committee of ILEP published a guideline for identifying patients
for referral for surgery (www.ilep.org.uk).31 The workshop participants felt that the
guidelines should be modified in light of current views and practice. They should be very
practical especially for the benefit of staff in integrated health services, who may only see a
limited number of leprosy affected persons. The workshop members felt that few centres are
aware of the current guidelines.

Assessment

In the selection of the surgical technique for correction of the paralysed hand, the surgeon
often makes a choice on the basis of presence and degree of mobility of the hand, notably
the proximal interphalangeal (PIP) joints. But what constitutes a (hyper) mobile or stiff hand?

The following is suggested:

. Hypermobile hand: in assisted extension the PIP joint(s) extend beyond neutral.
. Mobile hand: full assisted extension to neutral.

322 J. W. Brandsma & R. J. Schwarz

. Near mobile hand/finger: less than 10 degrees short of full assisted extension.
. Stiff hand/ finger: more than 10 degrees contracture.

These suggested definitions are given with the understanding that an effective extensor
mechanism is present.32,33

It is important to realize that a hand consists of four fingers, five if the thumb is included,
and that therefore there could be any combination of (hyper) mobile/stiff fingers that may
influence the choice of technique in a particular hand. It is good practice to compare the hand
with the other hand when that hand is unimpaired.

Little is known about long-term effects of reconstructive surgery in neuropathic hands.
Published research usually reports on improvement of angles or may report about grip
strength. In other words, most studies only report about effects at the impairment level.
Nothing is known about how surgery affects the leprosy-affected persons in their day-to-day
living, the activity level, or the socio-economical level (participation level). The problems
that leprosy affected persons experience may be at these levels. It may be that these will be
alleviated by surgery, which is at the impairment level, but little is published in this area. The
relationship between impairment and disability has been researched but not in the context of
reconstructive surgery.34,35

The recently developed SALSA scale (Screening for Activity Limitation and Safety
Awareness), primarily developed for patients with neuropathic limbs has some potential
use.36 The scale has seven questions that relate to work and another five that have to do with
dexterity. The main drawbacks of this scale to evaluate the effects of surgical interventions
would be that the questions are too general, and that many activities can be done by
substitution. To be able to evaluate the effect of surgical intervention it is important to take
hand dominance into account and substitution, but also the condition of the non-operated
hand, which may be impaired.

The Basic Activity of Daily Living Scale, developed in Karigiri, has the same drawback
for evaluation of surgical interventions. This scale does not take into account whether
activities are executed with the (non) dominant hand or with both hands, or if activities are
done in the usual and expected manner.

The Participation (restriction) Scale also has been developed recently to assess if, and to
what extent, patients with neuropathic limbs may experience participation restrictions and to
be able to assess to what extent these may be remedied with rehabilitative interventions.37,38
The main draw back to use this scale to evaluate the effect of surgery would be that in many
leprosy affected persons the score will be confounded by virtue of other impairments and
activity limitations that determine the presence of participation restrictions.

Other scales and questionnaires in common use in hand surgery and hand therapy would
often be too general, disease specific, or would not take into account that the neuropathic hand
in leprosy affected persons often has loss of protective sensation. The DASH (Disability of
Arm and Shoulder Hand) has become a widely used instrument in recent years in the
assessment and evaluation of interventions in upper extremity pathology.39 This instrument is
not culturally appropriate for leprosy affected persons in that it asks for some activities that
are not commonly practised in these countries. For a review of available instruments across
the three ICF domains of functioning, see MacDermid.40 It appears that for surgeons and
therapists to be able to evaluate the impact of interventions across the three dimensions of
disability different instruments need to be used.

Re-enablement of the neurologically impaired hand – 1 323

Conclusions/recommendations

BEST PRACTICE

In the rehabilitation of neuropathic hands, which includes surgery, and its effects on the
patients’ functioning, the terminology of the ICF should be used.

The naming of operations should be more informative and descriptive, e.g. palmaris
longus transfer with Lasso insertion, not just Lasso operation or FDS intrinsic replacement.

The primary reason for correction of claw finger correction in dynamic (tendon transfer)
procedures is the restoration of primary MCP flexion. The term ‘lumbrical replacement’ is a
misnomer.

In most ulnar nerve palsies, four fingers should be corrected even though there may be
only two-finger clawing present (overt clawing). Index and middle finger primary MCP
flexion will be weak in most cases due to paralysis of the ulnar-innervated interossei and they
will frequently progress to clawing (hidden or latent clawing).

It is recommended that the current ILEP guidelines for identifying patients for referral for
surgery be updated/rewritten.

To confirm the long-term result of surgical intervention, assessment should be carried out
for at least 2 years postoperatively.

Surgeons and therapists treating persons with neuropathic hands should have a good
understanding of the biomechanics of the hand and how the various reconstructive procedures
may affect hand function.

RESEARCH

A randomized clinical trial is needed to assess possible beneficial effects of neurolysis on
nerve function recovery in leprosy neuropathy.

Instruments (or parts of instruments) need to be identified, or otherwise developed, to be
able to evaluate the effects of surgery for intrinsic paralysis in the hand with peripheral
paralysis and loss of sensation at all three levels of disability.

Now that a dynamometer is available that can quantitate the strength of individual finger
movements, research should be done to determine to what extent the different techniques to
correct claw finger deformity determine grip and pinch strength.41,42

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