Original Article
Amer et al.: Sensory recovery in finger tip injuries
Sensory Recovery in Finger Tip Injuries
Tarek A. Amer 1, Ashraf A. Enab 2, Sameh A. El-Nomani 1, Neveen M. El-Fayoumy 3
Departments of Surgery, Cairo University1, Beni Suef University2;
Clinical Neurophysiology3, Cairo University; Egypt
ABSTRACT
Background: Traumatic amputation of the tip of the finger is a common injury both in domestic and industrial settings
and it is the most common injury seen in upper extremity. Several options for the management of this type of injury are
available. These options include surgical and conservative management. The main aim of these options is coverage and
retaining sensation of the finger tip. Objective: The aim of this study is to compare sensory recovery using two point
discrimination test and sensory nerve conductions following conservative management versus local flaps in finger tip injuries
without bone exposure. Methods: Sixty-four fingers in 58 patients are included in this study. Thirty-three finger tips were
allocated to group 1 (conservative management) and 31 to group 2 (local non sensate flaps). Two point discrimination test
and sensory nerve conductions were done after one year. The incidence of infection, joint stiffness, cold intolerance and
hypersensitivity was also noted. Results: There was a highly statistically significant difference between the two groups as
regards the two point discrimination test, and peak latency, amplitude and conduction velocity of sensory nerves (p≤0.001)
with better values in group 1. Conclusion: sensory recovery presented by two point discrimination test and sensory nerve
conductions in patients under conservative management is much better than that achieved with local flaps and there is no
statistical difference in the incidence of cold intolerance or hypersensitivity between the two methods of treatment after one
year. (Egypt J Neurol Psychiat Neurosurg. 2010; 47(2): 325-330)
Key words: Fingertip injuries- two point discrimination - sensory nerve conductions-conservative management- local flaps.
INTRODUCTION
Traumatic amputation of the tip of the finger is a
common injury both in domestic and industrial settings
(1)
. Finger tip amputation is the most common type of
amputation injury in the upper extremity (2). The finger
tip is defined as the portion of the finger distal to the
plane of the major dorsal and volar skin creases at the
distal interphalyngeal joint (3).
The two-point discrimination test is the most
frequently used test for the assessment of the sensory
outcome after nerve repair (4). For dermatomal regions
of the arm and forearm, mean values ranged from 30.7
mm to 45.4 mm. In the hand, the skin overlying the
first dorsal interosseous muscle demonstrated
discrimination values of 21.0 mm while that covering
the volar surface of the tips of the thumb and long and
little fingers showed values of 2.6 mm. (5)
Sensory nerve conduction studies can add
much as evidence of diffuse sensory fiber
involvement, localized lesions involving a cutaneous
nerve or disorders that preferentially damage the
sensory fibers in a mixed nerve, so they are a
necessary part of any electrophysiologic evaluation
of peripheral disorder (6) .
Correspondence to Neveen Mohammed El-Fayoumy, clinical
neurophysiology unit, Cairo University; Egypt.
TEL.: +20123714317. Email:[email protected].
The treatment of finger tip amputations is
controversial and so, many treatment options are available.
These treatment options are either conservative
management or surgical treatment. The main aim of these
treatment options is to keep functional impairment to a
minimum. Of course regaining sensation at the finger tip is
the most important aspect of maintaining function in
finger tip injury3.
Aim of work:
This study was conducted to compare sensory
recovery using sensory nerve conductions and two
point discrimination test following conservative
management versus local flaps in finger tip injuries
without bone exposure.
PATIENTS AND METHODS
Study design and population:
This study included Sixty four finger tip injuries
in 58 patients. All patients were recruited from the
department of surgery, Kasr El-Eini hospital, Cairo
University, Egypt, and department of surgery BeniSuef University, Egypt.
Patients were allocated according to treatment
policy into:
a- Group 1: Thirty three finger tips received
conservative management.
b- Group 2: Thirty one finger tips were treated
using local non-sensate flaps.
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325
Amer et al.: Sensory recovery in finger tip injuries
Exclusion criteria:
Smokers, patients with peripheral neuropathy
(using nerve conductions) and diabetics were excluded
from the study. Patients with carpal tunnel syndrome
were also excluded by doing mid palm –wrist segment
sensory nerve conduction and sensory nerve
conductions from the other digits supplied by the
median nerve. Moreover, patients with bone exposure
or other associate hand injury were excluded.
On admission, adequate history taking, thorough
physical examination and X-rays were taken to exclude
associated hand injury.
Methods:
IClinical evaluation:
Two point discrimination test was conducted one
year post injury for both the treated finger and the same
finger in the opposite hand. The finger of the patient is
touched with the two points widely separated using blunt
objects then the patient must close his eyes and the pulp of
the finger is touched firmly with either one point or two,
starting with them far apart, and approximating them until
he begins to make errors. The threshold is thus determined
and the other hand can be compared. Normally a person
should be able to recognize two points separated by as
little as 2.6 mm on the finger pads5.
II-
Neurophysiological evaluation:
Sensory nerve conduction studies were carried
out in the clinical Neurophysiology Unit, Kasr El-Eini
hospital one year post-injury using a Nihon Kohden®
(Neuropack four mini) apparatus. The active and
reference electrodes are 4 cm apart with the active
placed 14 cm from the cathode and the stimulation is
applied with ring electrodes around the digits with the
cathode at the base of the digits and the ground is
placed between the pickup and stimulating electrodes
(orthodromic technique).
Normal values: peak latency 3.2±0.2 mseconds,
amplitude 10-90uv and conduction velocity 48-64.9
m/seconds7.
III. Surgical techniques:
A) Conservative management (group 1):
Adequate wound debridement was done
under regional ring block anesthesia,
following that the wound is dressed with
Vaseline impregnated gauze with fusidic
acid. The finger is covered with the cut
finger end of a sterile surgical glove for 48
hours. The patients are followed up in the
out patient clinic and dressing is changed
every 48 hours in the 1st week and twice
weekly after that until healing occur.
Patients started wide range of early motion
exercise from first day post injury.
B) Local flaps (group 2):
Under local anesthesia, adequate wound
debridement is done. Local flaps used are
V-Y advancement flap (15 cases), cross
326
finger flap (10 cases) and thenar flap (6
cases). Dressing change is done every 48
hours for 4 days. This is followed by motion
exercises except in cases with cross finger
flap where it was done after flap separation
after 21 days.
The incidence of infection, joint
stiffness, cold intolerance and hypersensitivity
was also noted.
Statistical Methods
Data were expressed as meanstandard deviation
(SD) or percentage (%). Comparison between the
numerical data of two groups was performed using
unpaired t test, Chi-square test used for comparison
between qualitative data which were presented as
frequencies and percentages. Pearson’s correlation
coefficient was used to determine significant
correlations between the different qualitative variables.
SPSS computer program (version 11) was used for data
analysis. P value is considered is considered highly
significant (**) if it was ≤ 0.001.
RESULTS
Sixty-four finger tip injuries in 58 patients were
included in the study. Forty fingers were injuries due to
industrial accidents and 24 injuries due to domestic
accidents. 40 patients were males (68.96 %) and 18 were
females (31.04%). The mean age of the patients at the
initial presentations was 36.1±8.75 years (range 19-55
years) (Table 1). 33 injured finger tips were treated using
conservative management (Group 1) and 31 were treated
using local flaps (Group 2). Two flaps were lost in group 2
so they were excluded from the study leaving only 29
injuries for evaluation in this group.
1-
Conservative treatment (Group 1) :
Thirty-three finger tip injuries were treated using
this method. After adequate debridement, the mean
surface area of the defect was 1.6 cm2 (range 0.5-2.2
cm2). No infection in any finger occurred during the
period of treatment.
Cold intolerance was detected in 9 fingers
(27.3%) after 3 months and only in 2 fingers (6.1%)
after one year. Hypersensitivity was noticed in 12
fingers (36.4%) after 3 months. After one year no
hypersensitivity was noticed in any finger, as shown in
Table (2). No joint stiffness was observed in any finger.
2-
Local flaps (Group 2):
Thirty-one fingers were treated using this method.
After adequate debridement the mean surface area of the
defect was 1.6 cm2 (range 0.6-2.1 cm2). Flap separation
in cross finger flap was done after 21 days. Two flaps
were lost, so they were excluded from the study leaving
only 29 cases for evaluation in this group.
Egypt J Neurol Psychiat Neurosurg. │April 2010 │ Vol 47 │ Issue 2
Amer et al.: Sensory recovery in finger tip injuries
Cold intolerance was observed in 8 fingers
(27.6%) after 3 months and in 2 fingers (6.9%) after
one year. Hypersensitivity was not noticed in any of the
fingers after 3 or 12 months. Joint stiffness did not
occur in any of the fingers. So, the difference in the
development of cold intolerance and hypersensitivity
between fingers treated conservatively and those
treated with local flaps was not statistically significant
after 12 month p>0.05, as shown in Table (2).
In the comparative and correlative results, we
used only data of 58 fingers after excluding the two lost
flaps and thumb, middle fingers, so we compared
index’s finger data only to be statistically compared
and correlated.
I.
Comparative results:
1. Two-point discrimination test:
There was a highly statistically significant
increase in two-point discrimination test in
patients with index injury (local flaps,
conservative), compared to the contra lateral
healthy index (p<0.001), as illustrated in Table
(3), also there was a highly statistically significant
increase in that test in patients with local flaps,
compared to those on conservative management
(p<0.001), as illustrated in Table (4).
2. Sensory nerve conduction studies among
patients with index injury:
There was a highly statistically significant
increase in peak latency in patients with local flaps,
compared to those on conservative management
(p<0.001), however, there was a highly statistically
significant decrease in the amplitude and conduction
velocity in patients with local flaps, compared to
those on conservative management (p<0.001), as
illustrated in Table (5).
II. Correlative results:
Correlation between sensory nerve conduction
parameters and two-point discrimination in the two
groups:
There was a highly statistically significant positive
correlation between two-point discrimination and peak
latency; however there was a highly statistically
significant negative correlation between two point
discrimination and amplitude, conduction velocity in
both groups, (p<0.001), as shown in Table (6).
Table 1. Descriptive results of patients with finger tip injuries.
Patients, data
Values
58
No. of patients
Age (years)
Mean±SD
Range
Sex
Male
Female
Number of fingers
Aetiology
Industrial accidents
Domestic accidents
SD standard deviation
*Data are expressed as number (percentage)
36.1±8.75
19-55
40(68.96%)*
18(31.04%)*
64(100%)*
40(62.5%)*
24(37.5%)*
Table 2. Complications among the two groups of patients with finger tip injuries after one year.
Complication
Cold intolerance
Hypersensitivity
Yes
2(6.1%)
Yes
0(0%)
Conservative management
No
Total
31(93.9%)
33(100%)
No
Total
0(0%)
33(100%)
Yes
2(6.9%)
Yes
0(0%)
Local flaps
No
27(93.1%)
No
0(0%)
P-value
Total
29(100%)
Total
29(100%)
1.0
Data are expressed as number (percentage)
Table 3. Two-point discrimination test among patients’ index and the contra lateral healthy index in finger tip injuries
Two point discrimination
Conservative management
Treated index
2.87±0.37
Local flaps
7.86±0.41
Contra lateral healthy index
2.12±0.17
P-value
2.27±0.22
0.001*
0.001*
Data are expressed as mean±standard deviation
*Significant at p<0.01
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327
Amer et al.: Sensory recovery in finger tip injuries
Table 4. Two-point discrimination test among patients with index injury.
Two point discrimination
Conservative management
Local flaps
Number
29
Mean±SD
2.87±0.37
29
7.86±0.41
P-value
0.001*
SD standard deviation
*significant at P≤0.01
Table 5. Sensory nerve conductions among patients with index injury.
Parameter
Peak
latency
Groups
Conservative management
No.
29
Mean±SD
3.57 ± 0.33
Local flaps
29
4.54 ± 0.59
Amplitude
Conservative management
29
18.65 ±3.53
Local flaps
29
14.58 ± 2.97
Conservative management
29
48.93 ±1.94
Local flaps
29
40.24 ± 5.64
Conduction
velocity
P-value
0.001*
0.001*
0.001*
SD standard deviation
*significant at P≤0.01
Table 6. Correlation between sensory nerve conduction parameters and two-point discrimination in both groups of
patients with finger tip injuries.
Variable
Peak latency
Amplitude
Conduction velocity
Conservative management
r-value
P-value
0.88
0.001*
-0.76
0.001*
-0.65
0.001*
Local flaps
r-value
0.65
-0.60
-0.63
P-value
0.001*
0.001*
0.001*
*Significant at P≤0.01
DISCUSSION
Since the treatment of finger tip injury is still
controversial, several options for the management of
this type of injury are available. These options include
surgical and conservative management. Surgical
treatment for finger tip injury includes a plethora of
options that have been developed over years. Among
these options are V-Y flaps with its modifications8,
volar advancement flaps9, homodigital island flap10,
heterodigital island flap and full thickness skin grafting
which, in absence of exposed bones, is frequently used
for defect coverage due to relative ease of the
procedure11. Treatment of fingertip injuries must be
individualized to the patient's age, sex, configuration
and composition of defect, digit injured, hand
dominance,
pre-existing
medical
conditions,
occupation, hobbies, and mechanism of injury. The
fingertip wound should be assessed for tissue loss. If
there is minimal tissue loss the wound can be debrided
and closed primarily. If the fingertip wound cannot be
repaired primarily and no bone is exposed, conservative
treatment may be considered12.
The main aim in management of hand injuries is
reduction of functional impairment. Of course, in case
328
of finger tip injury, this functional impairment would
be sensory loss. Sensory recovery with conventional
flaps leads to unsatisfactory results in a majority of
patients: an average of 6-mm to 8-mm two point
discrimination is reported by most authors13.
Neurosensory flaps obtain good results regarding
sensory recovery; however they require special surgical
experience14.
Conservative management aims at wound healing
by secondary intention which is caused by contraction
and epithelization of the scar tissue and surrounding
dermis that effectively reduce the subsequent size of
the wound14-16. Conservative treatment plays a
significant role in the management of finger tip
injuries, as was documented by Farrell14 and later by
Allen17 and S.P. Chow18. Buckley et al.19 studied the
conservative management of finger tip injuries. They
reported excellent results with a mean two point
discrimination test 4.1mm twelve months post
operatively. A prospective study of seven treatment
methods used on 200 fingertip injuries showed that
simple dressings gave excellent results if the lengthy
time to healing were taken into account20. Mennen and
Wise15 in a series of 200 finger tip injuries found a
healing time ranging from 20 to 30 days and good
Egypt J Neurol Psychiat Neurosurg. │April 2010 │ Vol 47 │ Issue 2
Amer et al.: Sensory recovery in finger tip injuries
functional recovery (two point discrimination test after
3 months after healing averaged 2.5 mm indicating near
normal sensitivity recovery). The same conclusion was
reached by Lee et al.21.
Although some authors believe that the size of the
wound is important and place size limitations on
wounds that can be treated conservatively22, several
studies showed that the size, location and involved
structures are not critically significant factors in the
conservative management of finger tip injuries15,21 and
some other authors even go further to the use of
conservative treatment in fingertip injuries with small
amount of exposed bone that can be cut below the level
of surrounding tissue23.
Finger tip injuries left to heal by secondary
intention do so by the process of granulation, wound
contraction and epithelialization. Granulation tissues
seem actually to replace lost tissue volume while
contraction pulls normally innervated skin over the
defect resulting in near normal sensation and reducing
the ultimate size of the scar and the newly formed
epithelium is relatively normal24.
The results of our study confirm the opinion of
previous authors. In the group treated conservatively,
there was a mean increase in two point discrimination
from 2.12±0.17 mm in the contra lateral normal digit to
2.87±0.37 mm in the treated digit. However in group 2
(treated with local flaps) , there was a mean increase in
two point discrimination from 2.27±0.22 mm in the
contra lateral normal digit to 7.86±0.41 mm in the
treated digit. This shows that conservative treatment is
superior to local flaps regarding sensory recovery.
In the current study, we compared sensory nerve
conduction parameters between both groups and they
revealed that there was a highly statistically significant
delay in peak latency and reduction of amplitude and
conduction velocity in patients with local flaps
compared to those under conservative management.
These findings could be attributed to either local nerve
injury or distal axonal damage which may be associated
with more severe proximal conduction slowing as
explained by Chang25 but not in the same injury as we
haven’t found such study in the literature, although
both distal demyelination or axonal degeneration could
alter proximal conduction properties and retrograde
axonal atrophy is the pathologic term for a reduction in
the diameter of proximal fibers.
Complications associated with conservative
management are usually minor and improve with time26.
Drawbacks of conservative management include cold
intolerance and hypersensitivity. Goitz et al.14 noticed
that cold intolerance occur in 1 ⁄3 of conservatively
treated patients; however this cold intolerance often
decreases with time. Cold intolerance in a consequence
of the injury itself (24) and higher incidence of cold
intolerance is noted with other methods of closure26.
Hypersensitivity can also do occur but they are usually
transient. Patients with remaining hypersensitivity
usually benefit from desensitization programs27. Joint
stiffness is also reported with conservative management;
however this can be easily prevented by early range of
motion exercise24.
In our study, after 3 months, cold intolerance was
noticed in 9 fingers in the conservatively treated group
(27.3%) and in 8 fingers in the second group (27.6 %).
After one year, cold intolerance was noticed in 2
fingers (6.1 %) in the conservatively treated group and
in 2 fingers (6.9 %) in the second group.
Hypersensitivity developed in 12 fingers in the
conservatively treated group (36.4%) after 3 months.
No patients complained of a hypersensitive finger after
12 months. In the group treated with local flaps, no
hypersensitivity was detected in any of the patients
either after 3 or 12 months. No infection or joint
stiffness occurred in either group; however two flaps
were lost in the second group.
The previously mentioned data and the statistical
studies show that sensory recovery in finger tip injuries
treated conservatively is better than those treated with
local non sensate flaps. Moreover, the difference in
development of cold intolerance and hypersensitivity
between fingers treated conservatively and those
treated with local flaps was not statistically significant
after 12 months.
Conclusion
Conservative treatment using repeated dressings
is an effective, simple and good option for treatment of
finger tip injuries without bone exposure. The sensory
recovery presented by sensory nerve conductions and
two point discrimination test in patients using this
technique has better values than that achieved with
local flaps and there is no statistical difference in the
incidence of cold intolerance or hypersensitivity
between the two methods of treatment.
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‫الملخص العربي‬
‫استعادة اإلحساس في إصابات أطراف األصابع‬
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