Delayed bilateral median nerve injury due to low-tension electric current

Nerve Pain after Burn Injury: A Proposed Etiology-Based Classification

BACKGROUND

Understanding the mechanism of nerve injury may facilitate managing burn-related nerve pain. This proposed classification, based on cause of nerve injury, was developed to enhance the understanding and management of burn-related nerve pain.

METHODS

This retrospective investigation included patients aged 15 years or older admitted to the burn center from 2014 to 2019. Burn-related nerve pain was patient-reported and clinically assessed as pain 6 months or more after burn injury, unrelated to preexisting illnesses/medications. The pain classification consisted of direct nerve injury, nerve compression, electrical injury, and nerve dysfunction secondary to systemic injury. The four categories were statistically analyzed between groups, using 52 variables.

RESULTS

Of the 1880 consecutive burn patients, 113 developed burn-related nerve pain and were eligible for validation of the classification: direct nerve injury, n = 47; nerve compression, n = 12; electrical injury, n = 7; and nerve dysfunction secondary to systemic injury, n = 47. Factors, significantly increased, that distinguished one category from another were as follows: for direct nerve injury, continuous symptoms (p < 0.001), refractory nerve release response (p < 0.001), nerve repair (p < 0.001), and pruritus (p < 0.001); for nerve compression, Tinel signs (p < 0.001), shooting pain (p < 0.001), numbness (p = 0.003), intermittent symptoms (p < 0.001), increased percentage total body surface area burned (p = 0.019), surgical procedures (p < 0.001), and nerve release (p < 0.001); and for electrical injury, Tinel sign (p < 0.001), intermittent symptoms (p = 0.002), amputations (p = 0.002), fasciotomies (p < 0.001), and nerve release (p < 0.001). Nerve dysfunction secondary to systemic injury was distinguished by significantly less Tinel signs (p < 0.001), shooting pain (p < 0.001), numbness and tingling (p < 0.001), pruritus (p < 0.001), fascial excision (p = 0.004), skin grafts (p < 0.001), amputation (p = 0.004), nerve releases (p < 0.001), and third-degree burns (p = 0.002).

CONCLUSION

A classification consisting of direct nerve injury, nerve compression, electrical injury, and nerve dysfunction secondary to systemic injury is presented that may guide patient management and research methods, with the goal of improving pain outcomes in burn-related nerve pain.

Electrocuted Hip: Late Consequences of Electrical Shock Injuries of Orthopaedic Relevance: A Case Report and Review of Literature

CASE

A 43-year-old man suffered household electric shock from 220 V alternating current when he accidently touched a live wire with his left hand. Subsequently, he was diagnosed to have osteonecrosis of the left femoral head and underwent total hip arthroplasty.

CONCLUSION

We suggest that the electric current could have thrombosed the terminal subsynovial vessels of the femoral head, leading to osteonecrosis. To the best of authors' knowledge, only 2 cases of osteonecrosis of the hip after electric shock have been reported in the literature. A literature review of the delayed consequences of electric shock injuries pertaining to orthopaedics is also presented.

Prevalence and associated predictors for patients developing chronic neuropathic pain following burns

BACKGROUND

Chronic pain, unrelated to the burn itself, can manifest as a long-term complication in patients sustaining burn injuries. The purpose of this study was to determine the prevalence of chronic neuropathic pain (CNP) and compare burn characteristics between patients who developed CNP and patients without CNP who were treated at a burn center.

METHODS

A single-center, retrospective analysis of 1880 patients admitted to the adult burn center was performed from 1 January 2014 to 1 January 2019. Patients included were over the age of 15 years, sustained a burn injury and were admitted to the burn center. CNP was diagnosed clinically following burn injury. Patients were excluded from the definition of CNP if their pain was due to an underlying illness or medication. Comparisons between patients admitted to the burn center with no pain and patients admitted to the burn center who developed CNP were performed.

RESULTS

One hundred and thirteen of the 1880 burn patients developed CNP as a direct result of burn injury over 5 years with a prevalence of 6.01%. Patients who developed CNP were a significantly older median age (54 years vs. 46 years, p = 0.002), abused alcohol (29% vs. 8%, p < 0.001),abused substances (31% vs. 9%, p < 0.001), were current daily smokers (73% vs. 33%, p < 0.001), suffered more full-thickness burns (58% vs. 43%, p < 0.001), greater median percent of total body surface area (%TBSA) burns (6 vs. 3.5, p < 0.001), were more often intubated on mechanical ventilation (33% vs. 14%, p < 0.001), greater median number of surgeries (2 vs. 0, p < 0.001) and longer median hospital length of stay (LOS) (10 days vs. 3 days, p < 0.001), compared to those who did not develop CNP, respectively. Median patient follow-up was 27 months.

CONCLUSIONS

The prevalence of CNP over 5 years was 6.01% in the burn center. Older ages, alcohol abuse, substance abuse, current daily smoking, greater percent of total body surface area (%TBSA) burns, third degree burns, being intubated on mechanical ventilation, having more surgeries and longer hospital LOS were associated with developing CNP following burn injury, compared to patients who did not develop CNP following burn injury.

Neurophysiological assessment of fatigue in electrical injury patients

To investigate for the presence of central and peripheral physiological fatigue in electrical injury (EI) patients with experiential fatigue. Eight EI patients and eight age-matched healthy volunteers were recruited. Motor evoked potentials (MEP) following transcranial magnetic stimulation (TMS) and M-waves from ulnar nerve stimulation at the wrist were measured from the right abductor digiti minimi. Fatigue was induced by 2 min of maximal voluntary contraction, and subjects were followed for 15 min of recovery. The experiment was performed twice for each subject. In one of the two sessions (randomly assigned), a blood pressure (BP) cuff was inflated during the first 75 s of recovery period to prolong muscle ischemia. Baseline measures showed no difference in central and peripheral conduction times. Cortical silent period was prolonged in patients compared to controls with no differences in abduction force. Decrement of MEP amplitude with consecutive TMS pulses was observed in the post-recovery period only with EI patients who had prolonged muscle ischemia induced by the BP cuff. The post-exercise M-wave area during contraction was significantly higher for patients. Prolonged cortical silent period in EI patients suggests that they had increased GABAB receptor-mediated cortical inhibition. The ischemia-induced decrement in consecutive MEP amplitudes post-exercise demonstrates greater physiological fatigue in EI patients after exercise. The greater increase in M-wave area of EI patients post-exercise suggests larger decrease in conduction velocity of muscle action potentials with exercise. These findings provide preliminary physiological correlates for increased central and peripheral fatigue in EI patients with experiential fatigue.

Neurodegenerative effect of electrocauterization on spinal nerve root: an experimental study

We investigated the number of degenerated neurons in spinal roots of rabbits after spinal surgery to test if electrocauterization causes neuronal loss. The number of degenerated neurons was higher in study group than in control group, and the number of live neurons was higher in control group than in study group. These results suggest that electrocauterization applied during spinal surgery is hazardous to spinal neurons and should not be applied unless required.

Peripheral nerve compression associated with low-voltage electrical injury without associated significant cutaneous burn

Although peripheral-nerve injury has been described as clearly related to electrical injury, that electrical injury is usually associated with third- and often fourth-degree burns. The report presented here describes three cases of low-voltage electrical injury with associated peripheral-nerve symptoms but without clinically significant cutaneous burns. The symptoms and clinical findings resembled peripheral-nerve compression. The presence of these symptoms and findings in the upper- and lower-extremities and the presence of bilateral involvement suggest a systemic electrical injury that resembles a peripheral neuropathy. Symptoms were relieved by the decompression of nerves at multiple sites in each extremity. Perineurial fibrosis was identified at the time of nerve decompression. It is proposed that the electrical injury causes maximal heat production at areas of minimal limb cross-sectional area. In these areas, the peripheral nerve is in close proximity to bone and fibrous tissue. This results in perineurial fibrosis and symptoms of a compressive peripheral neuropathy.

Electric injury, Part II: Specific injuries

Electric injury can cause disruption of cardiac rhythm and breathing, burns, fractures, dislocations, rhabdomyolysis, eye and ear injury, oral and gastrointestinal injury, vascular damage, disseminated intravascular coagulation, peripheral and spinal cord injury, and Reflex Sympathetic Dystrophy. Secondary trauma from falls, fires, flying debris, and inhalation injury can complicate the clinical picture. Diagnostic and treatment considerations for electric injuries are described in this article, which is the second part of a three-part series on electric injuries.

Electric burns: high- and low-tension injuries

From January 1993 to December 1997, 179 patients with electrical injuries were admitted to our burn unit. There were 55 patients with high-tension injuries and 124 patients with low-tension injuries. A high incidence of amputation (42%) is one of the characteristic sequelae of high-tension injuries, but no patients in this group of burns died. Early and serial debridement of necrotic tissue is our treatment of preference. The patient needs extensive rehabilitation and psychiatric support.