High-pressure injection injuries to the hand: A 14-year descriptive study.

BACKGROUND: High-pressure injection (HPI) injury is an unusual type of injury in hand trauma, which could lead to a serious morbidity. We aimed to assess the clinical presentation, management, and outcome with HPI injury of the hand.
METHODS: A retrospective study was conducted between 2001 and 2015 for patients with HPI injuries who were admitted to a Level 1 trauma center. We reviewed the medical records, imaging files, and demographic data including gender, age, mechanism of injury, and site of hand injury. The kind of injected materials, time to first treatment procedure, clinical management, and complications were also described.
RESULTS: A total of 32 cases of HPI injuries were included in the study. The average age of the patients was 32.7 ± standard deviation 8.3 years, and all the patients were right handed. The most common material involved was grease (53%), followed by paints (25.0%), chemicals (9.4%), and air (6.3%). The most commonly affected part of the hand was the palm (31.3%), followed by index finger (25.0%). The average delay in the presentation was 12 h (range 3-96 h), and the mean hospital stay was 5.8 days. Management included debridement (90.6%) or conservative treatment (9.4%). Complications included chronic pain (9.4%), followed by amputation (3.1%).
CONCLUSIONS: HPI injury is not uncommon, usually underestimated, and needs more community awareness, particularly laborers. Delay of treatment could increase the risk of amputation. Therefore, it is important to inform the risk groups about the seriousness of such injuries and to take preventive measures.

INTRODUCTION

High-pressure injection (HPI) injuries to the hand are serious and bear a significant morbidity to the patient's hand. HPI injury is an unusual type of injury in hand trauma care and usually underestimated as mostly were reported from case reports.[12] Missed HPI injury is a major cause of treatment delay, and it can lead to poor function of the fingers and palm or even the amputation of a digit.[3] Evidence shows that the amputation rate of HPI injuries with inadequate treatment is 16%–48%.[14] The nondominant hand is the general site for grease HPI injuries as the grease is usually held in the other hand.[567] Injection commonly occurs in the index finger (>50%), second in the thumb (<40%), and the least in the hand, palm, or elsewhere (10%).[89] Treatment outcome and prognosis are directly related to the substance injected, the pressure exposure, the digit involved, and the time delay to surgical care. Previous studies revealed that the frequently injected materials are paint, automotive grease, solvents, diesel oil, air, or water.[345678910111213] The long-term consequence related with these types of injuries is the compressive effect occurring from the pressure of injection, amount of material, and the edema fluid.[14] It is important to identify the category of material injected and potential surgical urgency. The objective of the present study is to find out the clinical presentation, management, and outcome in patients who were admitted to a Level 1 trauma center with HPI injuries of the hand.

METHODS

This study was conducted retrospectively between 2001 and 2015 on patients presented with HPI injury. We reviewed the medical records, imaging files, and demographic data including gender, age, hand dominancy, and site of the injury and injured finger. The kind of injected materials, time to the first treatment procedure, clinical management, complications (early and late), follow-up duration, treatment, as well as the days of hospitalization were recorded. Ethical approval was granted by the Medical Research Center at Hamad Medical Corporation with the Institutional Review Board (IRB #16337/16), and data were retrieved anonymously. Data were also analyzed with respect to the presentation of HPI injury according to the nature of the material. Data analyses were performed using Epi Info version 7.2, Division of Health Informatics and Surveillance, Center for Surveillance, Epidemiology, and Laboratory Services, Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA30329-4027, USA. Descriptive statistics were used to present the data. Mean ± standard deviation (SD) was used for quantitative data. Inferential statistics were used for the generalization of values using 95% confidence interval (CI).

RESULTS

A total of 32 cases of HPI injuries included in the study were from trauma surgery department, which is considered the main surgical hand center in the country. Table 1 shows that the average age of patients was 32.7 ± SD 8.3 years, all the patients were right handed.

Table 1

Demographics, clinical and injury characteristics, and management of high-pressure injection injury (n=32)

Variable	Value
Age	32.7±8.3
Males	32 (100%)
Nature of the material
Grease	17 (53.1%, CI 35.8-70.4)
Paint	8 (25.0%, CI 10-40)
Chemical	3 (9.4%, CI 0-19.5)
Air	2 (6.3%, CI 0-14.7)
Others	2 (6.3%, CI 0-14.7)
Dominant right hand	32 (100%)
Affected hand
Right	17 (53.1%, CI 35.8-70.4)
Left	15 (46.9%, CI 29.6-64.2)
Site of hand injury
Palm	10 (31.3%, CI 15.2-47.4)
Index finger	8 (25.0%, CI 10-40)
Middle finger	5 (15.6%, CI 3.0-28.2)
Ring	3 (9.4%, CI 0-19.5)
Fourth webspace	2 (6.3%, CI 0-14.7)
Second webspace	1 (3.1%, CI 0-9.1)
Thumb	1 (3.1%, CI 0-9.1)
Index finger and palm	1 (3.1%, CI 0-9.1)
Middle finger and ring	1 (3.1%, CI 0-9.1)
Delay (hours)	12 (3-96)
Duration of admission (days) median, range	5 (1-18)
Clinical management
Debridement	29 (90.6%, CI 80.5-100)
Conservative	3 (9.4%, CI 0-19.5)
Operating room frequency (median, range)	1 (1-3)
Early complications
Raw area (no covering of skin)	1 (3.1%, CI 0-9.1)
Late complications
Chronic pain	3 (9.4%, CI 0-19.5)
Amputation	1 (3.1%, CI 0-9.1)
Raw area	1 (3.1%, CI 0-9.1)
None	27 (84.4%, CI 71.8-97)
Follow-up (months)	2 (1-5)

CI: Confidence interval

The most common material involved in HPI was grease (53.1%, 95% CI (35.8, 70.4), followed by paints (25%), chemicals (9%), and air (13%). Grease injuries were mostly encountered at the dominant hand in 88% of cases, whereas half of the air injuries and all the chemical injuries were in the dominant hand. All the paint injuries were in the nondominant hand. The most affected site of the hand was the palm (31.3%, 95% CI (15.2, 47.4), followed by index finger (25.0%, 95% CI (10, 40)). Figures 1-3 show the examples of HPI injuries in our study.

Figure 1

(a) Entry point at the palm of a grease material that was injected accidentally by gun. (b) Dorsal aspect of the left index finger with clear demarcation of the necrosis. (c) Volar aspect of the left index finger that shows black discoloration after few hours from accidental injection of paint under high pressure

Figure 3

(a) Bruner incision to explore the injected material which follows the least resistant course through the track of the neurovascular bundle. (b) The highly injected lead material removed out of the affected hand

(a) Swollen right hand after accidental injection of the MasterInject material. (b) MasterInject – low viscosity adhesive material – is excised from the dorsum of the hand. (c) MasterInject material that was excised from the left hand. The material is used for sealing cracks in concrete and restoring its structural integrity

The average time from injury to presentation was 12 h (range 3–96 h). The average hospital stay was 5.8 days. Most of the grease material injuries needed debridement (94%), whereas all the chemical and paint injuries needed debridement and half of the air injuries were managed conservatively. The average number of operations was 1 (range 1–2) except for the paint materials which was 2 (range 1–3).

Table 2 shows that the most common late complication was chronic pain in 9% of cases, but the incidence of chronic pain in palmar injuries was 18%. Amputation was required in only one patient who had paint injury which represented 12.5% of paint injuries and 3% of the total HPI injuries.

Table 2

Presentation of high-pressure injection injury according to the nature of the material

	Chemical (n=3)	Paint (n=8)	Grease (n=17)	Air (n=2)
Age	37.3±10.1	36.1±10.5	30.7±7.3	32.5±2.1
Affected hand (%)
Right	3 (100)	0 (0.0)	12 (70.6)	2 (100)
Left	0 (0.0)	8 (100)	5 (29.4)	0 (0.0)
Site of hand injury (%)
Middle finger	1 (33.3)	0 (0.0)	4 (23.5)	0 (0.0)
Index finger	0 (0.0)	3 (37.5)	3 (17.6)	0 (0.0)
Thumb	0 (0.0)	1 (12.5)	0 (0.0)	0 (0.0)
Ring	0 (0.0)	3 (37.5)	0 (0.0)	0 (0.0)
Palm	1 (33.3)	0 (0.0)	7 (41.2)	2 (100)
Fourth webspace	0 (0.0)	0 (0.0)	2 (11.8)	0 (0.0)
Second webspace	1 (33.3)	0 (0.0)	0 (0.0)	0 (0.0)
Index finger and palm	0 (0.0)	0 (0.0)	1 (5.9)	0 (0.0)
Middle finger and ring	0 (0.0)	1 (12.5)	0 (0.0)	0 (0.0)
Delay (hours)	8 (7-72)	11 (6-96)	10 (3-96)	12 (12-12)
Duration of admission (days) median, range	5 (4-10)	6 (1-18)	5 (3-14)	2.5 (2-3)
Clinical management (%)
Debridement	3 (100)	8 (100)	16 (94.1)	0 (0.0)
Conservative	0 (0.0)	0 (0.0)	1 (5.9)	2 (100)
OR frequency (median, range)	1 (1-2)	2 (1-3)	1 (1-2)	1 (1-1)
Early complications (%)
Raw area (no covering of skin)	0 (0.0)	1 (12.5)	0 (0.0)	0 (0.0)
Late complications (%)
Chronic pain	2 (66.7)	0 (0.0)	1 (5.9)	0 (0.0)
Amputation	0 (0.0)	1 (12.5)	0 (0.0)	0 (0.0)
Raw area	0 (0.0)	1 (12.5)	0 (0.0)	0 (0.0)
None	1 (33.3)	6 (75.0)	16 (94.1)	2 (100)

Lack of skin coverage occurred only in paint injuries at a rate of 13% as an early complication and 13% as a late complication. Secondary infection, tendinosis, contracture, and abnormal scarring were not reported in cases with early debridement and early occupational therapy.

DISCUSSION

This is a unique study from Qatar that describes the HPI injuries in a rapidly developing country, in which 85% of the population are expatriates. Accidental injection of grease, diesel, paint, and other materials is the reason for HPI injuries to the hand. These materials are mistakenly injected with a pressure from 40 to 800 atm, with a velocity up to 180 m/s, which can easily penetrate the skin through protective gloves without direct contact with the hand.[1516] Previous studies[117] reported that gasoline, oil, grease, paint, paint thinner, and water are the common materials injected by the patients. Grease and paint are the most commonly injected substances in our study, which supports the findings of other studies.[117] Chemical irritation, vascular spasm, edema, necrotizing inflammatory reaction due to cytolytic properties of injected substances, and lastly infection are the factors involved in developing severe damage to the vital and delicate soft tissues of the hand.[17]

Similar to other studies,[41718] index finger was injured more commonly in our study. On the contrary, dominant hand was injured more commonly in our study. Prognosis of the injury is related to the nature of the injected substance (chemical solvents and paint are more irritating than others), pressure, volume, site, and time to treat.[418] Necrosis, intense and severe damage, is often caused by a higher pressure.

After HPI, initially after injury, the presenting signs and symptoms are usually minimal, and pain and swelling are not significant. The entrance of foreign materials is a small pinprick, and this can lead both the patient and health-care personnel to underestimating the injury, which in turn results in a delay in the initiation of the classic treatment and urgent decompression. Eventually, the injured part becomes swollen and painful. In a few hours, it turns edematous, pale, and cold, and the chance for irreversible damage and amputation increases.

In our study, one patient underwent amputation, and the injected material was paint. It was a nondominant left ring finger, which was operated on after 8 h from the injury. Amputation risk was much less compared to other studies which was about 16%–55%, with an additional risk of 50%–80% when the injected substance is a solvent.[119] Time to treat is another prognostic factor for the risk of amputation. Eight cases of paint injuries were operated after an average of 22 h (range 6–96 h). Stark et al. recommended treatment during the first 10 h after injury in their study for better outcome.[20] Rosenwasser et al. reported that they did amputation for patients with more than 72-h delay.[16] In our study, the mean time from presentation to the first procedure was 12 h (range 3–96 h) for 32 patients and among them, only one patient underwent amputation. This low rate of amputation in our patients could be in part related to the nature of the injected material, which was grease most of the time. The other possible factor is the initiation of primary surgical decompression and debridement as soon as possible after admission to the hand surgery department. According to the literature, a small percentage of injured patients can resume their original work and duties.[8] This indicates the devastating nature of this kind of injuries. Management should include identification of the nature of the injected material as a priority to rule out any possible systemic intoxication.[19] Prompt surgical intervention should be carried out and foreign bodies and necrotic tissue must be removed early using a wide microsurgical exploration.[19]

There are few limitations for our study. The retrospective nature of the study is a limiting factor. The sample size was small; however, we intended to enroll all the presented cases across the study period. Cases were consecutive but separated by long periods; however, our hospital was the only tertiary hospital that could deal with such cases in the country.

CONCLUSIONS

HPI injury could be underestimated, and this study urges clinicians to pay more attention to early diagnosis and prompt treatment. HPI needs early surgical decompression in conjunction with other classic procedures. Initial delay of presentation, inadequate treatment, or misdiagnosis could negatively alter the outcome of HPI. Therefore, it is important to inform people who are at high risk about the seriousness of such injuries and to take appropriate preventive measures.

Research quality and ethics statement

The authors of this manuscript declare that this scientific work complies with reporting quality, formatting and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to require Institutional Review Board / Ethics Committee review, and appropriate approval (IRB #16337/16) was granted by the Medical Research Center at Hamad Medical Corporation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.