Hand injuries due to injection of substances by high-pressure industrial devices is a pathology which the family doctor may have to face. These are rare lesions (0.025-0.25% of the hand injuries) that mostly affect the first finger of the non-dominant hand. Apparently benign but with high risk of substantial long-term morbidity, undervalued many times. Mistakes in the initial management of these injuries can cause serious functional sequelae and amputations. The aim of this article is to review and summarize the main concepts of etiopathogenesis, diagnosis, treatment and prognosis of these lesions, as well as the lines of action in their prevention, in order to raise awareness among health personnel for the need to administer a quick and aggressive treatment in the first hours, to avoid complications and consequences so important that they can reach 48% of finger amputations. (Medical action need be standardized). Since the three main prognostic factors are the characteristics of the injected substance (type, amount, pressure and temperature), the anatomical area damaged and the time elapsed between the accident and the start of treatment, it is evident that early treatment determines the result. It is the only factor that the physician can change. Prevention is probably the issue to address to achieve the challenge of reducing the final consequences as much as possible.

Keywords: high-pressure injection injury, hand, prognostic factors, finger amputations, hand injuries, etiopathogenesis, diagnosis, hyper pressure, gun, injectors, compressed air, oxygen, helium

The injuries by high-pressure injection of substances are infrequent (0.025-0.25% of the injuries of the hand) but are however extremely dangerous as a result of the serious affects that they produce, being able to limit the future function of the affected limb. Despite being infrequent injuries, the primary care physician who carries out his activity in emergency services must be aware of them, without underrating their apparent lightness and requiring the assessment of specialists because the absence of emergency treatment can make the lesion evolve towards a state of irreversible sequelae. Since Rees¹ in 1937 first recorded and described a case of this type in written literature, we have witnessed a progressive increase in the use of high pressure systems in the industrial sector, a medium in which these injuries are mostly present, although the improvement and greater awareness of the correct use of PPE (personal protective equipment) in the last decades make their incidence proportionally lower. Nonetheless, injuries produced by the injection of a liquid or gaseous substance, generally in the pulp of the index finger of the non-dominant hand, come from a high pressure system (gun, injectors) that develop an output pressure of the material from 140 to 700 Kg / cm² and a speed exceeding 300 m/sec., which is sufficient to overcome the primary protection cutaneous barrier and harm deeper structures. There are many substances that can be involved in this type of work accidents, of two main types, fluids (gas oil, paint, brake fluid, water, grease-oil, polyurethane, ..) and gas (compressed air, oxygen, helium, ..), the most frequent being grease and oil, followed by painting.²

Physiopathology

The pathophysiological mechanism is based on three factors: mechanical effect, hyper pressure and chemical irritation.^3,4 The mechanical lesional effect that every particle in motion, with its corresponding kinetic energy, produces when impacting soft tissues, especially the ones with noble structures, such as vessels and nerves, can even cause a rupture of tendons, as reported by Costas-Chavarri.⁵ The hyper pressure that the injection of any substance produces on relatively inextensible anatomical areas such as the hand, can cause a vascular blockage effect that can lead to ischemia and compartment syndrome. The chemical irritation reactivates the injection of foreign substances in our body, such as the formation of olegranulomas secondary to the injection of fats, formations that according to Vinogradoff⁶ could evolve towards malignization, or necrosis of the subcutaneous cellular tissue by dissolving the lipids in the presence of industrial solvents.

Anatomical area

Regarding the anatomical lesional area, the injection occurs more frequently in the fingers, affecting more to the palm of the non-dominant hand, and within these the second, followed by the first and third, being there a greater incidence in the volar zone than the back, area in which there is a greater risk of spreading the substance injected by the presence of the tendon sheath.

Diagnosis

The diagnosis must be mainly clinical, supported by the different diagnostic means. Unfortunately, these are relatively unknown and undervalued lesions, and in the first hours there may be no more signs than a punctate wound from which a small amount of the injected liquid or blood can emanate, which gives it an appearance of apparent benignity. Subsequently there is edema, pallor or cyanosis, local anesthesia and a progressive functional limitation, which in the absence of emergency treatment can evolve to a necrosis and infection at 24-48 hours. We should be alert about the possible establishment of a primary compartment syndrome (due to the high pressure caused by the injection of a gas or fluid) or secondary syndrome (due to the toxic effects of the injected substance)⁷ Complementary diagnostic means are of great help, the realization of a conventional radiological study (evaluation of radiopaque material, gas) being necessary (Figure 1); the magnetic resonance would provide an adequate valuation of the tissue damage and degree of propagation of the material injected.

Treatment

Prognosis

The prognosis of these injuries will depend on the affected area (worse on the fingers, since they are less distensible areas than the hand), the type of material injected (paints, solvents and brake fluid are of worse prognosis), temperature, quantity and degree pressure, as well as the time elapsed between the injury and the start of treatment (the higher it is, the worse the prognosis).

Prevention is a fundamental aspect in the management of this type of accident, given that, as we have said, these are injuries with a high rate of complications and sequelae, the type of substance and the characteristics of its injection, being aspects more related to industry than to medicine.

The family doctor must know these lesions and have an action procedure like the algorithm proposed by Verhoeven.⁹ It is very important that the injured is immediately transferred to an emergency unit, where the doctor will take into account the characteristics of the product used and the industrial injection system, assess the state of the hand and general condition of the patient and decide the attitude to follow with the support of the orthopedic surgery specialist. The injury-treatment interval, in which an adequate coordination between the paramedical and medical team (since the accident warning is given, the transfer to the hospital center is properly carried out and a specific specialized protocol is applied) significantly reduces the degree of final sequelae, emergency surgical debridement being known to reduce the risk of amputation.¹⁰ Although the use of corticosteroids is under discussion¹¹ the authors recommend the use of i.v. of 250 mgr. of prednisolone diluted in 100 ml of saline solution in a single preoperative dose, there being no evidence that its use in the acute phase increases the risk of infection or the incidence of amputation,¹⁰ avoiding an acute inflammatory response to the fluid injected. Unfortunately, even after a early and adequate treatment, the complications and sequelae are frequent and important: tissue necrosis (Figure 3), infection, fibrosis that evolve towards rigidities, digital atrophy and complex regional pain syndrome, the most feared one being the compartment syndrome. The digital amputation rate after these injuries is 48%,¹² reaching 100% when the substance is injected at a pressure higher than 500 kgr/cm², according to the review carried out by Schnall.¹³ Remember that amputation is not only carried out by the appearance of complications such as necrosis or infection, but also by the presence of a stiff finger, which sometimes, especially in manual workers,¹⁴ can become annoying and even cause subsequent accidents when handling industrial machinery. However, the main complication is the initial underestimation of the lesion, which leads to a delay in treatment and a greater number of sequelae,¹⁵ so an adequate initial medical action is crucial. Prevention is the Gold Standard in the management of these injuries, based on three actions: the continuous training of workers who handle these systems of injection of substances, the investigation of substances which are more water soluble and less harmful to the organism, and the improvement in Individual protection equipment and development of industrial safety devices (automatic stop in emergency situations, automatic unblocking, ...) in compliance with labor legislation.¹⁶ The accurate treatment of these lesions has its limitations in terms of the final result of the functionality of the hand, so it is necessary that medical science and industry continue to work together to reduce the aggression and sequelae of this type of accidents.

Figure 1 Finger paint injection.

Figure 2 Finger X-ray: plumb paint.

Figure 3 Index finger pulp necrosis.

Lesions of the hand due to high-pressure injection are apparently mild lesions in the first hours, which can evolve towards severity with important and perhaps irreversible sequelae. The general practitioner should know this pathology, be alert and act quickly with an adequate assessment of the local and general state of the patient, consider the characteristics of the injected substance and request urgent help from the qualified surgeon for its rapid treatment, since the final functional state of the hand will depend on it.

None.

The author declares there is no conflict of interest.

1. Rees CE. Penetration of tissue by fuel oil under high pressure from a diesel engine. J Am Med Assoc. 1937;109:866–867.
2. Jebson PJ. High-pressure injection injuries of the hand. Wis Med J. 1993;92(1):13–16.
3. Failla JM, Linden MD. The acute pathologic changes of paint-injection injury and correlation to surgical treatment: a report of two cases. J Hand Surg Am. 1997;22(1):156–159.
4. Sirio CA, Smith JS, Graham WP. High-pressure injection injuries of the hand. A review Am Surg. 1989;55(12):714–718.
5. Ainhoa Costas-Chavarri, Tolga Turkey, In: Joseph E editor. Kutz Hand (NY). 2012;7(1):121–123.
6. Vinogradov I. Uber Spatfolgen kiintstliche Oleogranulome. Arch f klin Chir. 1936;187;69–78.
7. Pinto MR, Turkula-Pinto LD, Cooney WP, et al. High pressure injection injuries of the hand: review of 25 patiens managed by open wound technique. J Hand Surg. 1993;18(1):125–130.
8. Sanjay Saraf. High-pressure injection injury of the finger. Indian J Orthop. 2012;46(6):725–727.
9. Verhoeven N, Hierner R. High-pressure injection injury of the hand: an often underestimated trauma. Case report with study of the literature. Strat Traum Limb Recon. 2008;3(1):27–33.
10. Hogan, Christopher J, Ruland, et al. High-pressure injection injuries to the upper extremity: A review of the literature. J Orthop Trauma. 2006;20(7):503–511.
11. Rosenwasser M, Wei D. High-pressure Injection Injuries to the Hand. J Am Acad Orthop Surg.2014;22(1):38–45.
12. Schoo M J. High-pressure injection injuries of the hand. J Trauma. 1980;20(3):229–238.
13. Schnall SB. High pressure injection injuries to the hand. Hand Clin. 1999;15:245–248.
14. Irisarri C. Cirugía de la mano traumática. ENE ediciones. Madrid. 1987:82–83.
15. Delgado Serrano PJ, Sánchez Lorente TJ, Fuentes Sanz A. High-pressure metal injection injury of the wrist. Patología del Aparato Locomotor. 2006;4(1):12–16.
16. Raymond G. Hart MD, Gillian D. et al. Prevention of high-pressure injection injuries to the hand. Am J Emerg Med. 2006;24(1):73–76.