Avoid the upper outer quadrant of the buttock for intramuscular injection because of the risk of injury to the sciatic nerve. For immunisations, use alternative recommended sites. For drugs that need to be given by intramuscular injection, the ventrogluteal area is safer.

Sciatic nerve injury from an intramuscular (IM) injection into the buttock is potentially devastating. In severe cases, the hamstrings and all the muscles below the knee are paralysed resulting in a flail numb foot. This avoidable complication has been known about since the 1920s and highlighted in the nursing research literature ( 1 - 3 ). However, the majority of doctors are involved in prescribing drugs that may be given by IM injection (e.g. vaccines, vitamins, steroid hormones, analgesics and major tranquillisers), and safe injection practices should concern all health professionals. The aims of this study were twofold: to establish if sciatic nerve injury because of IM injection is a continuing problem, and to determine the availability of published guidelines on IM injection techniques within nursing organisations in the UK, USA and Australasia.

A review of the English language literature between 1989 and May 2009 was conducted using Medline and ISI Web of Science databases using combinations of the following keywords: sciatic nerve, peroneal nerve, fibular nerve, tibial nerve, sciatic neuropathy, paralysis, IM, injection injury, iatrogenic, malpractice and medicolegal. Secondary references were retrieved from article bibliographies. A Cochrane Library search was performed using the terms sciatic nerve and IM injection. The English medicolegal literature during the same period (1989–2009) was searched using the legal databases Lexis, LegalTrac, eCarswell and the International Digest of Health Legislation. Google search engine was used to identify any additional cases (restricted to the first 300 hits using the search term ‘sciatic nerve injection injury’). Sciatic nerve injury from causes other than IM injection was excluded as were IM injection injuries to other nerves.

The following nursing organisations were contacted and asked if they published any guidelines on the suitability of alternative IM injection sites and whether they had any position on intragluteal injection: the Royal College of Nursing (UK), New Zealand Nurses Organisation, Australian Nurses and Midwifery Council, American Nurses Credentialing Center, American Association of Colleges of Nursing, American Association of Critical Care Nurses, the National League of Nurses (USA) and the National Council of State Boards of Nursing (USA).

We reviewed IM injection related sciatic nerve injury claims to the New Zealand Accident Compensation Corporation (ACC) between July 2005 and September 2008. New Zealand has a population of 4.2 million, and all New Zealanders and visitors to the country who suffer a physical injury can apply to the Corporation for assistance. This can include claims for injury as a result of treatment. The anonymised data used in this analysis were reviewed by ACC staff and meet the Corporation’s Ethics Panel guidelines for external research and publication of ACC information.

Seventeen reports of patients with sciatic nerve injury from IM injection were identified comprising a total of 1506 patients, at least 80% of which were children ( Table 2 ) ( 5 - 22 ). Most of the medications being administered were antibiotics or analgesics but a broad range of drugs were involved. There were no relevant reports in the Cochrane Library. Nine court decisions finding in favour of the plaintiff were identified ( Table 3 ) ( 23 - 32 ). All were in adults and processed by the North American legal system. A nurse was responsible for administering the IM injection in at least eight of the patients.

Only one of the nursing organisations contacted, the Royal College of Nursing (UK), has published guidelines on the technique of IM injection, and these relate specifically to immunisation ( 4 ). The other nursing organisations were unable to direct us to any published guidelines, although the New Zealand Nurses Organisation informed us that they support nurses using the ventrogluteal rather than the dorsogluteal site for IM injection.

Eight claims for sciatic nerve injury from IM injection were made to the ACC during the 3‐year study period ( Table 1 ). All were young adults. Six instances occurred in a general practice setting. All injections were administered by a registered health professional but the experience and type of professional (doctor or nurse) were not recorded. Four patients were documented during the fiscal year 2007–2008 and one in each of the other fiscal years under study. All affected patients experienced pain and a combination of muscle weakness, sensory disturbance and difficulty in walking. The documented cost per case to the ACC till September 2008 was between 32 and 1503 New Zealand dollars.

Discussion

Iatrogenic injury to the sciatic nerve resulting from a misplaced gluteal IM injection is a persistent worldwide problem affecting patients in economically rich and poor countries alike, albeit with a different spectrum of affected individuals. In economically poorer countries, children make up the greatest number of reported cases. In a nationwide study in Pakistan between 2001 and 2003, the estimated annual incidence of traumatic injection neuropathy (more than 90% of which involved the sciatic nerve) was 7.1 per million children under 3 years old (33). In countries such as Pakistan, India and Nigeria, the administration of IM injections by inadequately trained or unqualified staff seems to be an important cause (8-10, 12, 13). The problem is compounded by erroneous beliefs that IM injections work faster or reflect better quality care.

The effects of injection related sciatic nerve injury are variable ranging from transient sensory disturbance to permanent paralysis and numbness (18). Affected children may be unable to walk or crawl; a significant proportion present with foot drop (9, 10, 13). The common fibular component of the sciatic nerve is more often affected because of its posterolateral position and smaller amount of supporting connective tissue (34). Anatomical variations in the course and division of the sciatic nerve may be a factor in some cases (11). Affected patients typically experience immediate pain radiating down the limb, with weakness and numbness evolving more gradually (35), exacerbated by secondary scarring. The extent of recovery depends on the severity of the initial injury. Many patients (8-11) fail to make a full recovery, even with the benefit of microsurgical repair (11).

Common sites for IM injection are the anterolateral thigh, deltoid and gluteal regions. The latter can be subdivided into dorsogluteal (commonly known as the upper outer quadrant of the buttock) and ventrogluteal (between the iliac crest, greater trochanter of the femur and anterior superior iliac spine). Immunisation guidelines in the UK (4, 36), USA (37) and Australia (38) recommend that the buttocks should not be used for IM injection because of the risk of injury to the sciatic nerve; the anterolateral thigh in infants or deltoid region in older children should be used instead. A caveat is generally added that the upper outer quadrant of the buttock can be used for large volume IM injections. However, immunisations aside, the potentially hazardous dorsogluteal site is still widely used for IM injection of drugs (2) and continues to be recommended in nursing texts (39) and clinical practice (40).

The buttocks are an inviting site for IM injection because of their obvious (muscle) bulk but the term ‘upper outer quadrant’ lacks precision. The buttock is defined as ‘one of two protruberances of the rump’ (41), whereas the gluteal region extends between the iliac crest superiorly and the gluteal fold inferiorly all the way from the midline posteriorly to a line joining the greater trochanter of the femur and anterior superior iliac spine laterally. Use of the dorsogluteal region not only risks damaging the sciatic nerve but it also is not a good site for IM injection. In one study of 100 consecutive adults, the depth of adipose tissue in this region was beyond the 35 mm limit of a 21 g (green) needle in 43% (42). In another study of 50 hospitalised patients receiving an IM injection in the ‘upper outer quadrant’ of the buttock with a 30 mm length needle, injections were IM in only 32% of patients (8% in women); most were subcutaneous (43).

No IM injection site is without hazard, including the anterolateral thigh and deltoid regions. In the gluteal region, the ventrogluteal area (Figure 1) is safer, with only one reported significant complication (44). This site has less subcutaneous fat (43), offers the combined thickness of gluteus medius and minimus muscles, has relatively minor nerves and blood vessels and can be accessed with the patient on his/her side or lying supine (2). Despite this, nurses have been reluctant to use this site (2, 39, 40); a recent survey in New Zealand showed that only 9% of nurses had used this site (45). This may partly be because of the lack of confidence in identifying the area (40, 45). Perhaps the cumbersome term ‘ventrogluteal’ should be replaced with an alternative, such as the ‘gluteal triangle’, to avoid confusion with the dorsogluteal region and the buttock.