Keywords
Neurological Examination - Percussion - Neurology - History - Reflex, Stretch
Palavras-chave
Exame Neurológico - Percussão - Neurologia - História - Reflexo de Estiramento.
INTRODUCTION
In 1945, Professor Wartenberg, the world-famous neurologist, stated in his seminal
book The Examination of Reflexes that “testing of reflexes and their proper evaluation undoubtedly constitute the
most important part of the neurologic examination.”[1] Percussion with a reflex hammer is useful in the neurological examination[1]
[2]
[3]
[4] as it helps the examiner to define the nature of the neurological disease. The technique
has been used in medicine since the 1760s and was first adopted in neurological examinations
in the 19th century.[2]
[5] Many different reflex hammers have been designed over the years. We present a review
of the history of the main types and investigate the favorite reflex hammer of Brazilian
neurologists.
METHODS
The authors searched on Pubmed and Scielo original and review articles about historical
aspects of reflexes and reflex hammers with the following search terms: “reflexes”,
“reflex hammer”, “history of reflexes”, “examination of reflexes” and “neurological
examination”. Furthermore, we conducted an online survey to investigate the favorite
reflex hammer of Brazilian neurologists. The survey depicted the following aspects:
sex, age, neurology timing (resident or years as a neurologist), institution of residency
training, favorite personal reflex hammer, reasons for that choice, and if it reflects
the preferred choice of your institution. The online survey was made on Google Forms,
the link to answer the questionnaire was sent by email and WhatsApp and the results
were organized on an Excel spreadsheet.
RESULTS AND DISCUSSION – HISTORICAL REVIEW
Percussion
The first description of the use of clinical percussion dates from 1761. The Austrian
physician Leopold Auenbrugger (1722-1809) used the technique that year to examine
the chest and abdomen of patients for the presence of fluids. His inspiration came
from observing winemakers, who thumped wine casks to estimate the wine volume.[5] By 1826 the technique was widespread in clinical practice, and in 1828 the Scottish
physician David Barry (1781-1836) developed the first percussion hammer, inspired
by the Swiss veterinary practice of percussing the skull of cattle to investigate
the presence of hydatid cysts.[6]
The history of reflex hammers
In 1826, Pierre Adolphe Piorry (France, 1794-1879) described percussion with a device
known as the pleximeter. Shortly after this, in 1828, the Scottish doctor David Barry
developed a small hammer to strike the pleximeter.[5] In 1841, the German physician Max A. Wintrich (1812-1882) created what proved to
be a popular hammer, and this was followed in 1854 by another hammer developed by
Henry Vernon.[5]
[7]
[8] In 1875, in simultaneous publications, Wilhelm H. Erb and Carl F. O. Westphal described
muscle stretch reflexes and the importance of the use of percussion hammers for assessing
them. From then on percussion hammers were called reflex hammers and began to be produced
on a commercial scale.[5] In the USA, two models were developed: the first by John Madison Taylor (1855-1931)
in 1888, which was popularized by Silas Weir Mitchell, who introduced the graduation
system to patellar reflex: KN + , KN + + and KN-[9]; and the second by William C. Krauss (1863-1909), who incorporated gadgets to test
temperature and touch sensations.[6] For many years Taylor's reflex hammer was featured in the American Academy of Neurology
logo together with a tuning fork.[5] In 1910, Ernst L. O. Trömner (1868-1930) developed a reflex hammer with two percussion
heads, a larger one for large tendons, and a smaller one for flexor tendons. In 1927,
Henry W. Woltman (1889-1964) was greatly impressed by Trömner's hammer and bought
several of them, both for his own use and for use by his colleagues at the Mayo Clinic,
where he worked and where the hammer became a traditional professional item among
neurologists.[5] In 1910, in Germany, Bernhard Berliner (1885-1976) developed a model with a heavier
head and larger striking surface.[2] Also in Germany, in 1912, E. Ebstein modified Wintrich's hammer adding accessories
to test sensation.[5]
[8] In 1912, in France, Joseph J. F. F. Babinski (1857-1932) developed two hammers.
One had a disc-like head with a rubber ring around the edge, while in the other the
disc was replaced by a rectangular plate, which also had a rubber ring around its
edge. Shortly afterwards, in 1920, Abraham Rabiner (1892-1986) modified one of Babinski's
hammers, making its head articulable allowing its use either parallel or perpendicular
to the handle. This model became known as the Babinski-Rabiner hammer.[5]
[10] Concurrent, Joseph J. Dejerine (1849-1917) developed a reflex hammer with a cylindrical
head made entirely of rubber.[6] In 1922, in the USA, the neurosurgeon Byron Stookey (1887-1966) developed his own
hammer based on Wintrich's design. At that time, Stookey was examining patients with
peripheral nerve injuries sustained during World War I.[11] The Queen Square hammer was developed around 1925 and was based on Vernon's hammer.
Its name is a tribute to the National Hospital for Nervous Diseases, where it was
invented by Miss Wintle, head nurse of the physiotherapy and radiology service. She
wrapped a brass disk with a ring-shaped pessary and secured it to a bamboo rod to
give a dense, flexible, lightweight, and painless hammer.[5] Other models, such as those designed by Buck and Henri Meige, were updated versions
of the hammer developed by the Czech physician Josef Skoda (1805-1881), which Jean-Martin
Charcot (1825-1893) considered the best hammer for obtaining the patellar reflex.[5]
[12] On the other hand, Gowers suggested eliciting the knee jerk by using the ulnar surface
of the hand to strike the patellar tendon directly (Gower's maneuver). However, this
was not considered acceptable by J. Babinski.[10]
[13] During his daily clinical activities, William Osler (1849- 1919) used the rim of
his stethoscope to tap deep tendon reflexes.[14] The Queen Square hammer is the reflex hammer of choice of UK neurologists, while
at the Mayo Clinic Trömner's hammer is the preferred choice.[5]
[Figure 1] depicts the evolution of creation of the main reflex hammers and [Figure 2] their illustrations.
Figure 1 Timeline of the main reflex hammers.
Figure 2 The first reflex hammers (A-E) and the more common hammers in use today (F-K). Illustrations
are hand drawings made by one of the authors (ATM). Notes: A, Wintrich; B, Skoda;
C, Vernon; D, Krauss; E, Berliner; F, Taylor; G, Trömner; H, Babinski-Rabiner; I,
Dejerine; J, Buck; K, Queen Square.
Characteristics of reflex hammers
Taylor's hammer (1888; [Figure 2-F]) was the first to be produced on a commercial scale. It was lightweight with a triangular-shaped
rubber head and a short, flattened handle. The larger edge represented the ulnar surface
of the hand while the smaller edge was used to obtain more subtle reflexes. Over time,
it was noticed that the tip was better for assessing the plantar reflex.[5] The Krauss hammer (1894; [Figure 2-D]) allowed assessing reflexes and sensations. The handle, which was made of rubber,
became warm when rubbed, and could therefore be used to test thermal sensation, while
at the larger extremity of the handle, there was a hidden removable brush, which could
be used for testing tactile sensation. The head was made of metal and had a triangular-shaped
tool for testing pain sensation.[5] Trömner's hammer (1910; [Figure 2-G]) weighed about 100 grams and had an elongated head with different-sized rubbers
at either head and a tapered, flat handle. Berliner's hammer (1910; [Figure 2-E]) was a heavy tool made of nickel-plated metal. The head was hatchet-shaped and tapered
at the tip and had an edge covered with rubber. The Babinski-Rabiner hammer (1920;
[Figure 2-H]) was made of nickel-plated steel and had a cylindrical handle 20 to 25 cm long.
The head was circular, articulated, and covered with rubber. The Babinski-Rabiner
hammer differed from the Queen Square hammer in the material used to make the handle
and its length: the Babinski hammer was shorter and had a metallic handle, while the
Queen Square hammer was longer and usually had a bamboo handle (nowadays it is plastic).[5]
RESULTS AND DISCUSSION – ONLINE QUESTIONNAIRE
According to Conselho Federal de Medicina there are 4,960 neurologists with a principal active and regular inscription in Brazil,[15] from which 3,813 are subscribed to Academia Brasileira de Neurologia (ABN). The sample constituted of 558 responders represents 11.2% of all Brazilian
neurologists and 14.6% of those enrolled in the ABN.
The demographic characteristics of the participants are disposed in [Table 1].
Table 1
Demographic characteristics of the participants of the online survey
|
Characteristic
|
N
|
%
|
|
Sex
|
Male
|
316
|
57
|
|
Female
|
238
|
43
|
|
Age (years)
|
< 30
|
84
|
15.1
|
|
30–45
|
319
|
57.5
|
|
45–60
|
80
|
14.4
|
|
> 60
|
72
|
13
|
|
Neurology timing (years as neurologist)
|
Resident
|
54
|
9.7
|
|
< 5
|
157
|
28.3
|
|
5–10
|
121
|
21.8
|
|
10–20
|
100
|
18.1
|
|
> 20
|
122
|
22
|
[Figure 3] illustrates the Brazilian region of residency training of the responders. 530 participants
answered this question.
Figure 3 Brazilian region of residency training of the participants.
The frequency of reflex hammers chosen by the participants is disposed in [Figure 4]. The Babinski-Rabiner was the favorite among Brazilian neurologists (257; 46%),
and the Queen-Square was the second one (108; 19.3%). For those who chose the Babinski-Rabiner,
156 (60.7%) stated that it reflects their institution's choice.
Figure 4 Favorite reflex hammers of Brazilian neurologists.
Most of the responders (51.5%) consider that their choice did not reflect the preferred
choice of their institution of residency training. For those that consider that their
choice reflects the reflex hammer oriented by their chiefs in the institution where
they were trained (48.6%), 42.4% stated that most neurologists of their institution
use the same reflex hammer, and 6.2% stated that a minority use the preferred one.
Buck was the most controversy: it is the favorite reflex hammer of 22 participants
(3.9%), but only 3 stated that it is the preferred one of their institutions.
492 participants explained the reasons for their choice. Babinski-Rabiner's reflex
hammer showed the following qualities: better individual adaptation and ergonomics,
practical use, increased patient comfort, ease of evoking reflexes, heavy head weight,
good weight distribution between the handle and the head, articulated head that facilitates
transport and accessibility.
The reflex hammer's choice was homogeneous in all sets of ages ([Figure 5]) and it was very similar between men and women.
Figure 5 Reflex hammer's choice by age.
In conclusion, percussion is a key point of the neurological examination. A wide range
of reflex hammers is available nowadays, although many of the original models are
no longer marketed. The choice of a hammer is left to the neurologist as no single
model has been proven superior to the others.
