Background
Peripheral nerve injuries participate 10% of all injuries, and in 30% of extremity
injuries [[1]]. Brachial plexus injury represents a severe, difficult-to-handle traumatic event.
In recent years, the incidence of such injuries has gradually increased and the indications
for surgery have been challenged. Most information on the results of brachial plexus
repairs after missile injury has been derived from military reports. Brooks reported
the first large series in 1954 [[2]], followed by a few other authors reported their series [[3],[4],[5],[6],[7],[8],[9],[10],[11]]. Studies regarding missile injuries of the peripheral nerves have shown that these
injuries may be produced by low-velocity and high-velocity missiles that cause compressing
and stretching of the nerves [[7],[12],[13]]. The high-velocity missile injuries are the second most common cause of brachial
plexus lesions, accounting for about 25% [[14]].
Missile wounds, particularly those causing bone fractures, increased the risk of nerve
severance and irreparable damage [[15]]. In addition, other extensive injuries like soft tissue; visceral organ and blood
vessel injuries complicate the treatment and prognosis of the peripheral nerve injuries.
The patient’s outcome depends on the characteristics and site of injury, the coexisting
lesions, time of surgery, intraoperative findings, surgical technique, and postoperative
physical rehabilitation. In this paper, we present our experience with 265 patients
who had brachial plexus lesions caused by gunshot wounds.
Methods
Patient population
We reviewed the data of 265 patients with gunshot wounds who underwent evaluation
and treatment for 288 brachial plexus lesions between 1966 and 2007 at the Department
of Neurosurgery, Gulhane Military Medical Academy. Twenty-three patients were spontaneously
recovered without surgery; most of them had minimal sensory deficits and partial lesions
in electromyoneurography (EMNG) with lower trunk lesions. All patients who were treated
surgically (242 patients) were men and the mean age was 22-years (ranging between
19 and 30 years). One hundred and six patients had shrapnel injury and 159 patients
had bullet injury.
Physical and Neurological evaluation
The physical examination usually began with inspection of the overall symmetry and
observation of obvious scars related to either the initial trauma or subsequent surgery.
The range of motion of all joints and the neck were assessed. The supraclavicular
and infraclavicular areas were inspected and palpated for obvious scarring or bony
spurs. Calluses from malunions of the clavicle can be palpated, and their presence
could suggest compression of the underlying plexus.
It was important to keep in mind that high-velocity and fragmentary agents like grenades
and land-mines frequently cause nerve injury at several levels. Manual muscle testing
began by observing the muscle atrophy, the tone of each muscle group, and the muscle
force. Examination of sensibility included deep pain, touch and pin sensation, two-point
discrimination and some tactile location. A positive Tinel sign, elicited by tapping
the supraclavicular area, was a strong indicator of nerve rupture. Damage to these
nerves caused pain, numbness, and weakness in the shoulder, arm, and hand. The pain
could be severe, and was often described as burning, pins and needles, or crushing.
In general, the C5 nerve controls the rotator cuff muscles and shoulder function,
C6 controls flexing the arm at the elbow, C7 partially controls the triceps and wrist
flexion, and C8, T1 controls hand movements. When C5 and C6 are predominantly affected,
the most common symptom is referred to as an Erb’s palsy; these patients are unable
to lift their arm or flex at the elbow, and severe atrophy can occur in the shoulder
muscles. Another pattern of injury is when C8 and T1 are heavily damaged. These patients
have hand weakness and pain, although some finger movement may remain. The most severe
type of injury is when the arm is completely paralyzed as a result of extensive brachial
plexus injury. All brachial plexus lesions underwent neurological evaluations in the
preoperative stage and at the end of the follow-up period postoperatively. The muscle
strength grading and, sensorial grading scales were used for the evaluation of outcome
according to the preoperative time period, intraoperative nerve status, repair level,
type of surgery, and length of the graft. Coexisting damage around the nerve lesion
site were also listed. Because all patients were soldiers none of the data were lost
in the follow-up period.
Site of injury
The location of the lesions was defined according to the trunk, cord or nerve parts
of the brachial plexus elements. Injuries were located in the supraclavicular region
in 22 (8.3%) patients, and in the infraclavicular region in 243 (91.7%) patients.
The number of nerve element injuries resulting from shrapnel wounds was higher than
the number of injuries caused by missile wounds as documented in [Table 1].
Table 1
Summary of the surgically treated brachial plexus lesions according to the injury
site and wounding agent.
|
Location of Injury in Surgical Group
|
Number of Elements Evaluated Operatively
|
|
Missile Injury
|
Shrapnel Injury
|
Total
|
|
Spinal nerve to trunk or trunk (supraclavicular)(n = 22)
|
|
C5–C6 to upper trunk or upper trunk
|
7
|
6
|
13
|
|
C7 to middle trunk or middle trunk
|
11
|
12
|
23
|
|
C8 to T1 to lower trunk or lower trunk
|
4
|
3
|
7
|
|
Divisions to cord or cord (n = 141)(infraclavicular)
|
|
Lateral
|
24
|
43
|
67
|
|
Medial
|
82
|
87
|
169
|
|
Posterior
|
19
|
38
|
57
|
|
Cord to nerve or nerve (n = 102) (infraclavicular)
|
|
Lateral to musculocutaneous
|
13
|
18
|
31
|
|
Lateral to median
|
17
|
13
|
30
|
|
Medial to median
|
15
|
29
|
44
|
|
Medial to ulnar
|
12
|
11
|
23
|
|
Posterior to radial
|
21
|
37
|
58
|
|
Posterior to axillary
|
10
|
9
|
19
|
|
Total (265)
|
235
|
306
|
541
|
Initial surgical treatment
Soon after the injury, but before the nerve repair, all patients underwent initial
surgical treatment of the gunshot wounds, especially for the shrapnel injuries. Plastic,
vascular, chest and orthopedic surgeons repaired the soft tissue defects, blood vessels,
hemothorax or pneumothorax, and bone fractures near the nerve. The coexisting lesions
around the nerve injury site were detected during this initial evaluation, and the
axillary and subclavian arteries were those most often affected. After the resection
of necrotic soft tissues, the general or vascular surgeon performed reconstruction
of the blood vessels if necessary. Seventeen bone fractures which were coexisted with
nerve lesions were treated by orthopedic surgeons. The skin defects were treated by
plastic surgeons immediately after injury, using skin flaps or epidermal skin grafts
in 43 patients. 19 patients had the muscle defects including pectoralis major, pectoralis
minor, deltoid muscle and sternocleidomastoid muscle. These muscles fragments disrupt
the normal anatomy of the brachial plexus region, cause adhesions, and increase the
risk of vascular and neural damage during the surgery. Most of these defects were
caused by shrapnel injury which was secondary to landmine explosions. Hemothorax and/or
pneumothorax was detected in 6 patients with brachial plexus lesions and treated by
chest surgeons.
Most patients underwent initial management within the field military hospital without
a neurosurgeon or with insufficient equipment to evaluate and to treat the nerve injury.
After the initial procedures, the patients who were injured in other cities were transported
to our department for peripheral nerve lesions. Nevertheless, when the initial surgeons
found nerve transsection inside the wound and if the nerve defect was short and both
nerve stumps were exposed, the surgeons had to approximate nerve stumps to each other
with 1–2 paraneural nylon or silk sutures. If the gap was too long, they had to tack
the accessible stumps down to the surrounding tissue.
Timing of the repair
Indications for surgery included loss of nerve function without clinical and electrophysiological
improvement in the early post-injury months. Surgical procedures were performed from
6 weeks to 10 months after injury. The majority of the lesions, 149 (56.23%) of 265,
were repaired within the first 4 months. But early surgeries, during the first two
months) were performed in a few of cases, who had total transected nerve elements
that reported during the initial surgical procedures. Only 21 (7.92%) lesions were
repaired between 8 and 10 months after injury because these lesions were followed-up
by the orthopedic surgeons for bone fractures and wound infections before the operation
for nerve lesion. As previously described in the section of ’initial surgical treatment ’, most of the lesions were repaired within the first 6 months after injury. Incomplete
functional loss and/or incomplete and limited functional recovery during the observation
period were the reasons for delayed surgery. These patients were followed up monthly
by clinical and electrophysiological examinations during the observation period.
Intraoperative findings and surgical procedure
Operations were performed under general anesthesia. The patient was placed in opposition
and incisions were made in the usual manner, except in cases of localized circumstances
in the repair region (extensive scarring, skin flap, external skeletal fixation material,
and severe contracture), which required some modifications. Microsurgical instruments
and microscope were used especially during the decompression, neurolysis and anastomosis
of the neural elements. The majority of the intraoperative findings (65.26%) were
intact nerve elements, compressed by fibrosis, while 14 (2.58%) were completely ruptured
nerve elements, 39 (7.21%) were nerve elements in which nerve continuity was interrupted
by neuroma or fibrotic tissue at the stumps, 25 (4.62%) were partial nerve element
rupture, and 110 (20.33%) were intact nerve elements surrounded by fibrosis.
Surgical procedures included end-to-end interfascicular anastomosis with sural nerve
graft with or without neuroma excision (EEIA-SG) (4.44%), end-to-end epineural anastomosis
with or without neuroma excision (EEEA) (7.95%), end-to-end interfascicular anastomosis
with or without neuroma excision (EEIA) (9.05%), partial neuroma excision with EEIA-SG
(PNE+EEIA-SG) (2.22%), partial neuroma excision with EEEA (PNE+EEEA) (3.51%), partial
neuroma excision with EEIA (PNE+EEIA) (4.44%), interfascicular neurolysis (IN) (29.02%),
exploration with simple decompression and external neurolysis (SD + EN) (39.37%).
Intraoperative nerve stimulation techniques have been used to assess the nerve function
in most cases since the early 1980s, but this was not systematically practiced. If
the nerve was intact and compressed by the fibrosis, stimulation and recording electrodes
were placed on the nerve. Direct intraoperative recording of nerve action potentials
(NAP) guided management decisions; if action potential was transmitted across the
lesion, external neurolysis alone was performed. Neurolysis was mostly accomplished
both proximally and distally to the involved segment, and potential areas of entrapment
were released. When the scar tissue could not be removed appropriately from the nerve,
the epineurium was dissected and interfascicular neurolysis was performed. Simple
external neurolysis was used in 353 lesions, and interfascicular neurolysis in 110
lesions.
Complete nerve rupture and interruption with the neuroma or fibrosis at the stumps
were noted in 53 lesions. The stumps could be separated in some lesions still in the
same plane, and the stumps in the others, were directed to different planes, sometimes
grabbed by adjacent callus or abundant scar tissue. If the structures such as fibrosis
were seen without response to nerve stimulation, after the dissection of the epineurium,
these fibrotic parts of the nerve were removed. If there were fascicles-in-continuity,
and intact electrophysiologically, we protected them and performed decompression on
these nerve fibers. End-to-end epineural or interfascicular anastomoses were performed
at the nerve defect due to excision of fibrotic parts of the nerve. In 55 lesions,
we performed partial neuroma excision and end-to-end epineural or interfascicular
anastomosis with or without using sural nerve grafts.
Proximal and distal nerve stumps and non-transmitting nerve segments were resected
until the appearance of normal fascicles and vascular architecture with healthy epineurium.
The non-transmitting segments were characterized by abnormal color, unusual consistency,
and/or sparse or absent vascularization. Sometimes they were soft or, conversely,
diffusely fibrotic in cases when long-term local infection existed near the nerve.
The nerve defect was repaired by an end-to-end epineural anastomosis in 62 lesions,
end-to-end interfascicular anastomosis in 73 lesions, and end-to-end interfascicular
anastomosis with sural nerve graft in 36 lesions, by using monofilament interrupted
silk or nylon suture (Ethilon 8-0; Ethicon, Inc, Somerville, NJ). Before the choice
of suturing technique, the nerve stumps were mobilized reasonably, without tension
at the suture sites and the risk of wound dehiscence and, if it was possible, anastomosis
was performed without nerve grafting. Otherwise, repair with a nerve graft was necessary.
We used interfascicular technique (two or four grafts) and the sural nerve was preferred
as nerve graft. This nerve graft divided into two or four sections and end-to-end
anastomosed to the nerves using interfascicular technique. The length of the nerve
gap was measured after resection, and maximum mobilization of the nerve stumps and
graft was about 10% longer than the corresponding nerve defect. Physical therapy was
applied soon after injury in some cases, as well as after surgery in all cases. We
did not use the nerve transfers or neurotization as a surgical method.
Effects of coexisting injuries in the repair region
Gunshot-related damage on the soft tissues, vascular structures, bones, muscular structures,
and visceral organs, was frequently noted in the repair region; in our series, coexisting
injuries were detected in 95 of the 265 cases; bone fractures in 17, big vascular
injuries in 10, skin defects in 43, muscular defects in 19, and hemothorax/pneumothorax
in 5 cases. Most of the tissue and muscular defects were caused by shrapnel wounds.
Statistical analysis was performed on the relationship between the final outcome and
the injury level, the timing of repair, the intraoperative nerve status, the type
of surgery and the length of sural nerve graft, using a chi-square test. The statistical
significance was based on the p < 0.05 level.
Results
After the mean postoperative follow-up period of 20 months (range between 6 and 39
months), the motor and sensory recovery were scored on a scale ranging from 0 to 5
points, as recommended by the British Medical Research Council [[16]]. The sensory recovery scale was slightly modified, as seen in [Table 2]. A large number of the lesions were ≤S2 and M2 levels before the operation. The
results were classified into three groups. Good outcome was defined as ≥M4 and ≥S4,
fair outcome was represented by M2–M3/S2–S3, and poor outcome was ≤M1 and ≤S1. Twenty-three
patients (7.98%) who had minimal motor and sensorial deficits spontaneously recovered.
Table 2
Modified British Medical Research Council (BMRC) grading of sensorimotor recovery,
and motor recovery on the quality of outcome after brachial plexus repair [[16]].
|
Motor recovery
|
|
Poor
|
M0
|
No contraction
|
|
M1
|
Return of perceptible contraction in the proximal muscles
|
|
Fair
|
M2
|
Return of perceptible contraction in both proximal and distal muscles
|
|
M3
|
Return of perceptible contraction in both proximal and distal muscles of such of degree
that all important muscles are sufficiently powerful to act against resistance
|
|
Good
|
M4
|
Return of function as in stage 3 with the addition that all synergic and independent
movements are possible
|
|
M5
|
Complete recovery
|
|
Sensory recovery
|
|
Poor
|
S0
|
No sensation
|
|
S1
|
Deep pain re-established
|
|
Fair
|
S2
|
Some response to touch and pin, with over-response
|
|
S3
|
Good response to touch and pin, without over-response
|
|
Good
|
S4
|
Location and some tactile discrimination
|
|
S5
|
Complete recovery
|
Pain Management in Brachial Plexus Injuries
Injury to the brachial plexus may cause severe pain. Intractable pain was assigned
in 5 cases in our series with lower trunk lesions. Three of them exposed shrapnel
injury and the others exposed missile injuries. Pain usually starts a few days after
the initial trauma and can be intractable. It is commonly described as continuous,
burning, and compressing and is frequently located in the hand. All the patients were
initially treated with carbamazepin, amitriptyline, gabapentin, some antidepressants
and sympatholytic agents, and antipsychotic drugs. Excision of the neuroma and reconstruction
of the nerve was also the best treatment of the pain. In our patients, the early exploration
and reconstruction of the brachial plexus not only improved the function of the arm
but also relieved the pain.
Final clinical outcome and prognostic factors
Surgical level
Although the majority of the repairs had fair results, the good results were achieved
in upper trunks (53.85%) and lateral cords repairs (40.30%). The poor results were
significantly high in lower trunks (28.57%), medial cords (21.89%), and ulnar nerves
(21.74%). ([Table 3]) The results were not statistically significant because the p values were 0.268
when comparing spinal nerves and trunks, 0.074 when comparing the divisions and cords
and 0.851 when comparing the cords and nerves.
Table 3
Relationship between the final outcome of the brachial plexus lesions which were treated
surgically and the location of the lesion.
|
Final Outcome for Repair Level (%)
|
|
Location of Injury in Surgical Group
|
Good
|
Fair
|
Poor
|
|
Spinal nerve to trunk or trunk
|
|
C5–C6 to upper trunk or upper trunk
|
53,85
|
38,46
|
7,69
|
|
C7 to middle trunk or middle trunk
|
30,43
|
60,87
|
8,7
|
|
C8 to T1 to lower trunk or lower trunk
|
14,29
|
57,14
|
28,57
|
|
Divisions to cord or cord
|
|
Lateral
|
40,3
|
50,75
|
8,96
|
|
Medial
|
26,63
|
51,48
|
21,89
|
|
Posterior
|
38,6
|
49,12
|
12,28
|
|
Cord to nerve or nerve
|
|
Lateral to musculocutaneous
|
29,03
|
58,06
|
12,9
|
|
Lateral to median
|
36,67
|
56,67
|
6,67
|
|
Medial to median
|
31,82
|
59,09
|
9,09
|
|
Medial to ulnar
|
21,74
|
56,52
|
21,74
|
|
Posterior to radial
|
32,76
|
58,62
|
8,62
|
|
Posterior to axillary
|
21,05
|
63,16
|
15,79
|
Time of operation
When we evaluated the results according to sensory and muscle strength grading, good
outcome was achieved in the first 4 months (44.97%). The rate of the good outcomes
decreased when the preoperative interval was increased; good outcome was noted in
only 14.29% of the lesions in which the operation was delayed more than 8 months.
We could not get enough useful recoveries at the time of surgery more than 8 months
after injury. According to these results, the first 4 months after the injury seems
to be the critical period for surgery; ([Table 4]) however, the result was not statistically significant, according to the chi square
test (p = 0.129).
Table 4
Relationship between the preoperative time period and the final outcome.
|
The final outcome for preopertaive interval (%)
|
|
0–4 months (n = 149)
|
4–6 months (n = 60)
|
6–8 months (n = 35)
|
8–10 months (n = 21)
|
|
Poor
|
8,72
|
11,67
|
14,29
|
19,05
|
|
Fair
|
46,31
|
50
|
57,14
|
66,67
|
|
Good
|
44,97
|
38,33
|
28,57
|
14,29
|
Intraoperative findings and operative techniques
Significant good results were seen in lesions with nerve intact and only compressed
by fibrosis (71.67%), and with neuroma and/or fibrosis in-continuity (52.08%). ([Table 5]) The majority of the results were fair in lesions with complete rupture (71.43%),
interrupted by a neuroma and/or fibrosis at the end of the nerve (71.79%), and partial
rupture (64.00%). These results were statistically significant (p < 0.05). Nine surgical
techniques were performed in repairing the lesions, and the best outcome was found
in the 54.93% of lesions in which the exploration with simple decompression and external
neurolysis technique was used. Based on the surgical techniques, good recovery rates
were 16.67% for EEIA-SG, 25.58% for EEEA, 30.61% for EEIA, 16.67% for PNE+EEIA SG,
26.32% for PNE+EEEA, 30.33% for PNE+EEIA, 49.68% for IN, and 54.93% for SD+EN. The
majority of the results based on the surgical techniques were fair, with the exception
of the exploration with simple decompression, external neurolysis, and interfascicular
neurolysis. ([Table 6]) This results were statistically significant (p < 0.05).
Table 5
Relationship between the intraoperative nerve status and the final outcome.
|
The final outcome for intraoperative findings (%)
|
|
Complete rupture (n = 14)
|
Interrupted by a neuromaor/and fibrosis at the stump (n = 39)
|
Partial rupture (n = 25)
|
Neuroma or/andfibrosis is continuity (n = 110)
|
Nerve is intact, only compressed by fibrosis (n = 353)
|
|
Poor
|
21,43
|
20,51
|
16
|
5,45
|
3,68
|
|
Fair
|
71,43
|
71,79
|
64
|
43,64
|
24,65
|
|
Good
|
7,14
|
7,69
|
20
|
50,91
|
71,67
|
The final outcome for intraoperative findings (%)
Table 6
Relationship between the type of surgery and the final outcome.
|
The final outcome for type of surgery (%)
|
|
EEIA-SG (n = 24)
|
EEEA (n = 43)
|
EEIA (n = 49)
|
PNE+ EEIA-SG (n = 12)
|
PNE+ EEEA (n = 19)
|
PNE+ EEIA (n = 24)
|
IN (n = 157)
|
SD+EN (n = 213)
|
|
Poor
|
29,17
|
18,6
|
12,24
|
25
|
10,53
|
4,17
|
2,55
|
2,35
|
|
Fair
|
54,17
|
55,81
|
57,14
|
58,33
|
63,16
|
65,5
|
47,77
|
42,72
|
|
Good
|
16,67
|
25,58
|
30,61
|
16,67
|
26,32
|
30,33
|
49,68
|
54,93
|
Length of the graft
We used 3 cm grafts in 11 lesions, 3,1–5 cm grafts in 14 lesions, and 5.1 cm grafts
in 11 lesions. The maximum length of the sural nerve graft was 6,5 cm. Good outcome
was noted in 36.36% of lesions with grafts 3 cm or shorter, and in 14.29% of lesions
in the 3,1 to 5 cm group. We did not get good results in the repairs with grafts more
than 5,1 cm. Thus, 3 cm seems to be the critical length of the nerve graft to get
good clinical outcome. ([Table 7]) However, the p value was 0.055 for the comparison of the relationship between the
length of the graft and the final outcome, and the difference was not statistically
significant.
Table 7
Relationship between the length of the graft and the final outcome.
|
The final outcome for the length of the graft (%)
|
|
0–3 cm (n = 11)
|
3,1–5 cm (n = 14)
|
>5,1 cm (n = 11)
|
|
Poor
|
0
|
35,71
|
45,45
|
|
Fair
|
63,64
|
50
|
54,55
|
|
Good
|
36,36
|
14,29
|
0
|
Complications
Ninety-five coexisting lesions in the nerve injury site were detected during the initial
evaluation. Ten of these were vascular injuries that mostly affected the axillary
and brachial arteries. In one case, the axillary artery was lacerated at the proximal
repair line with the graft, during the dissection of the nerve elements, and the vascular
surgeons repaired the artery. Two patients with land-mine wounds, developed osteomyelitis;
we performed a simple decompression and external neurolysis technique in two nerve
elements in one case, and interfascicular neurolysis in one nerve element in the other.
After a course of antibiotics, and hyperbaric oxygen therapy for a month, these cases
improved, and we did not propose additional surgery.
Discussion
Brachial plexus lesions represent approximately 11.5% of our nerve injury population
at the Gulhane Military Medical Academy. These lesions are technically difficult to
explore and to treat; the anatomy is complex, great vessels are close to the plexus,
and intraoperative vascular injury is a risk factor for surgery. As a consequence,
we aimed to evaluate the final clinical outcomes and to determine the prognostic factors
in patients undergoing surgical treatment for brachial plexus lesions resulting from
gunshot wounds.
Although there have been some developments in microsurgical techniques, intraoperative
neurophysiology, and new repair techniques, the surgical treatment of peripheral nerve
injuries, resulting from gunshot wounds has not changed in its essentials since World
War II [[17]]. The results of the gunshot wounds to the peripheral nerves are neuropraxia, axonotmesis,
and/or neurotmesis injuries [[18]]. In older military series, low-velocity missiles, usually shell fragments that
damaged by direct impact, caused the most of the injuries. These injuries involved
neuropraxia or axonotmesis [[10]]. Patients with low-velocity missile injuries may display a significant return of
function within a few months [[19],[20],[21]]. On the other hand, high velocity missiles (especially footman rifle) injuries
have three mechanisms: direct impact, shock waves, and cavitation effects. These last
two mechanisms are more common and cause nerve stretching and compression. Patient
with high-velocity missile injuries have generally failed to display a significant
return of function [[10]]. Although complete transsections were more common in missile injuries, there was
no significant difference between shrapnel injury and missile injuries [[22]]. In the present study, most of the injuries were neurotmesis as a result of high-velocity
missile injuries. Most of the patients with injuries of upper trunk and posterior
cord with partial neurologic deficits, may display spontaneous neurological recovery,
but not those with injuries of the lower elements [[2],[9]]. In the published series, various numbers of cases with incomplete functional loss
display a significant return of function [[2],[7],[9]]. In our series, only 23 patients (7.98%) who had minimal motor, and sensorial deficits
were spontaneously recovered. The indication for surgery was the neurological deficit
in the distribution of one or more elements of the plexus, without improvement between
6 weeks and four months after the injury. The injury affected one nerve element in
94 cases (87 of them exposed missile injury, and the others exposed shrapnel injury),
two nerve elements in 74 cases (59 from missile injury, 15 from shrapnel injury),
three nerve elements in 56 cases (9 from missile injury, 47 from shrapnel injury),
and four nerve elements in 29 cases who exposed shrapnel injuries. Some authors have
reported that the best results were obtained with an early operation and repair of
the nerve injuries [[9]]. If lesion-in continuity was found with neurological examination and electrophysiological
tests, resection was delayed for 3 to 6 months to allow for possible spontaneous recovery.
When there was no of spontaneous recovery during this period, resection of the lesion
was indicated.
The time of the surgery for nerve injuries was largely dependent on patients’ referral,
which may cause a significant delay. The nerve must be surgically explored within
3 months after injury, if no significant functional recovery is noted [[23],[24],[25]]. Surgery delayed up to 6 months was not pragmatically unfavorable during this period,
surgery was indicated if anatomic recovery seemed to stop or fail, if there were differences
between the motor and sensorial recoveries, or if there was uneven functional recovery
with regular chronology but an absence of improvement in some muscles [[4]]. If surgery is delayed longer than 1 year, results will not be good, and this may
be one of the reasons for conservative treatment [[4],[8]].
Generally, the clean wound without infection, a stable fracture, restoration of circulation
and skin closure over neurovascular structures are priorities and should be reasons
for delayed nerve repair [[26]]. Early surgical exploration is not indicated, because of the possibility of spontaneous
recovery, and it is difficult to evaluate the extent and severity of the nerve damage
[[27]]. This is one of the reasons for surgical delay in our series. Soon after the injury
and before the nerve repair, all patients underwent initial surgical treatment of
the missile wound, especially in cases with shrapnel injury. After they recovered
without complications from the initial operation, they were admitted to us for definitive
treatment of nerve lesions. The postoperative recovery period was a major reason for
the surgical delay in this study because of the need for an observational period for
spontaneous recovery. We performed surgical treatment in 209 cases within the first
6 months after injury.
According to some authors, the surgery on of brachial plexus lesions resulting from
gunshot wounds was rarely profitable and justifiable because recovery at infraclavicular
levels occurred better than that at supraclavicular levels [[2],[6]]. In supraclavicular levels, the recovery at C5, C6, and some C7 spinal nerve repairs
was better than that at C8, and T1 spinal nerve repairs. Neurolysis and surgical repair
of the lower elements rarely improved functional recovery but only helped with pain
relief. At the cord level, the results of repair were favorable for lateral and posterior
cord and their outflows. In our series, we noted the best recovery results in upper
trunk repairs, and suggesting that the adult patients with C8, T1 spinal nerves, lower
trunk or medial cord incomplete lesions are suited for conservative treatment unless
pain is not manageable by pharmacological means, because surgical repair have a low
yield regarding ultimate functional recovery.
Studies regarding peripheral nerve injury caused by gunshot wounds have shown that
most lesions are caused by both direct bullet trauma and by the indirect heat and
shock to adjacent tissue [[7]]. These injuries present a specific problem in peripheral nerve surgery because
of the mechanism of injuries. Gunshot wounds to the brachial plexus usually result
in lesions- in- continuity, but, the patients with a large majority of these lesions-in-continuity
had complete functional loss [[2],[6],[7],[11]]. Intraoperative stimulation and NAP recording studies are important in assigning
whether the nerve elements need resection or not. In our series, 13 nerve elements
ruptured completely, and 38 elements were interrupted by neuroma or fibrosis. In 23
nerve elements, partial rupture was noted. The majority of nerve lesions-in-continuity
were compressed by fibrosis in the present study. More than 50% of repaired nerves-in-continuity
with neuroma or/and fibrosis and compressed by fibrosis had good outcome. The worst
outcome was seen in lesions with completely ruptured nerve elements. Surgical procedure
was determined with the operation microscope images and intraoperative stimulation
and NAP recording studies. If the nerve is intact and has compressed or is surrounded
by fibrosis and has partial ruptured nerve elements, the best way to evaluate the
lesion of the nerve is to stimulate and record the nerve across the injury site by
intraoperative nerve conduction stimulation. The presence or absence of an intraoperative
NAP helps to determine further operative management. The presence of a NAP beyond
an injury site indicates preserved axonal function or significant axonal regeneration,
which augurs well for clinical recovery. The absence of a NAP has been correlated
histologically with a Grade IV Sunderland lesion, inadequate regeneration and poor
clinical recovery. NAP studies have been performed with all lesions in continuity
[[28],[29],[30]]. The presence of NAP indicates neurolysis, and absence indicates that recovery
will not proceed without resection and repair of the lesions [[28],[29],[30]]. The peripheral nerve has to be able to adapt to neurolysis and repair by slacking
down (approximately 15% of their total length) and by elongation (4.5%) [[31]]. Except in patients treated with external and interfascicular neurolysis, the nerve
stumps were mobilized before suturing so that no tension was exerted on the suture
sites. If possible, anastomosis was performed without using nerve grafts. In some
cases, repair with autograft was necessary. The length of the gap between nerve stumps
was measured after resection, and maximal mobilization of the nerve stumps and graft
was about 10% longer than the corresponding nerve defect. Useful functional recovery
(Grade 3) was reported in more than 90% of neurolyzed cases [[6],[7],[10]]. In our series, good results were seen in 54.93% of the simple decompression and
external neurolysis group, and in 49.68% of the interfascicular neurolysis group.
According to Kline, approximately 69% of lesions repaired by suture and 54% of lesions
repaired by grafts had successful outcomes [[7]]. In another study, the rate of recovery was 67% for primary suture, and 54% for
nerve grafting [[6]]. Samardzic stated that the rate of the functional recovery was 87.8% among the
lesions which were repaired by nerve grafts [[10]]. In our series, good results were obtained in 30.61% of end-to-end interfascicular
anastomosis group, 30.33% of the partial neuroma excision and performed interfascicular
anastomosis group, in 26.32% of the partial neuroma excision and performed epineural
anastomosis group, and in 25.58% of the end-to-end epineural anastomosis group. The
good results were achieved as the same ratio (16.67%) for the lesions repaired by
partial neuroma excision and interfascicular anastomosis with sural nerve graft, and
the interfascicular anastomosis with sural nerve graft with total neuroma excision
or not.
Functional recovery after graft placement depends on the severity of injury and the
graft length [[11],[17],[23],[24]]. In addition, the small-caliber grafts are better than larger-caliber grafts [[32],[33]]. We used sural nerve grafts, which are small-caliber nerves. Although many authors
have stated that the length of the nerve defect influences outcome, experimental data
have revealed that other factors may also contribute to the poor results after the
use of long nerve grafts [[34]]. Good results are possible in cases of long nerve defects [[35]], although, along with numerous other authors [[11],[23],[24],[36],[37]]. we found that worse results correlated with increased graft length. We obtained
good outcome in 36.36% of lesions repaired with 3 cm or shorter sural nerve graft
and suggest that 3 cm is the critical length of the nerve graft to get good functional
outcome.
A few studies address the dependence of nerve repair outcomes on comorbidities fractures,
main vascular lesions, and soft tissue (skin, muscle) defects and so on in the nerve
repair region [[6],[11],[24],[38]]. These comorbidities may influence the final outcome of the nerve in its own manner:
for example great vascular lesions aggravate the results through ischemia, and bone
fragments may cause additional nerve damage during the initial missile trauma or subsequent
callusing spreads around the repaired nerve. An associated vascular injury will warrant
emergency repair [[39],[40]]. In addition to transections of a major vessel, gunshot wounds involving the brachial
plexus may produce pseudoaneurysms or arteriovenous fistulas that compress the plexus
and produce progressive loss of function and severe pain. Injured elements need to
be dissected and gently moved away from the area of vascular repair. In our series,
there were coexisting injuries in 95 of the 265 cases.
Conclusion
Since peripheral nerve injury has no fatal course but a spectrum of morbidity, appropriate
repair of injured nerves is important in retaining quality of life for the patient.
Although gunshot wounds usually leave the nerves intact, and several authors have
stated that these lesions sometimes recover spontaneously; surgery is indicated for
most of them. We conclude that appropriate surgical techniques help recovery, especially
in the lesions with complete functional loss. Intraoperative appearance of the nerve
and the type of surgery are the prognostic factors of the patients’ final functional
outcome.
Abbreviations
EMNG:
Electromyoneurography
EEIA+SG:
End-to-end interfascicular anastomosis with sural nerve graft
EEEA:
End-to-end epineural anastomosis
EEIA:
End-to-end interfascicular anastomosis
PNE+1:
Partial neuroma excision with EEIA-SG
PNE+2:
Partial neuroma excision with EEEA
PNE+3:
Partial neuroma excision with EEIA
IN:
Interfascicular neurolysis
SD+EN:
Simple decompression and external neurolysis
NAP:
Nerve action potentials
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
HIS designed the study, performed surgeries for many of these patients and drafted
the manuscript. IS acquired the data. IA analysed the data and performed the statistical
analyses. YI performed linguistic and technical corrections. BD made substantial contributions
to conception and design of the study. MKD participated in the study design, performed
surgeries for many of these patients and revised the manuscript. EG read and approved
the final version of this manuscript. All authors read and approved the final manuscript.
