◊ BACKGROUND:
Peripheral nerve injuries represent a notable source of anaesthetic complications and can be debilitating. The objective of this study was to identify associations with peripheral nerve injury in a broad surgical population cared for in last decade.
◊ METHODS:
At a tertiary care university hospital, the quality assurance, closed claims, and institution-wide billing code databases were searched for peripheral nerve injuries over a 10-yr period. Each reported case was individually reviewed to determine whether a perioperative injury occurred, defined as a new sensory and/or motor deficit. The location and type of the injury were also identified. Nerve complications as a result of the surgical procedure itself were excluded, and an expert review panel assisted in the adjudication of unclear cases. Patient preoperative characteristics, anaesthetic modality, and surgical speciality were evaluated for associations.
◊ RESULTS:
Of all patients undergoing 380,680 anaesthetics during a 10-yr period, 185 patients were initially identified as having nerve injuries, and after review, 112 met our definition of a perioperative nerve injury (frequency = 0.03%). Hypertension, tobacco use, and diabetes mellitus were significantly associated with perioperative peripheral nerve injuries. General and epidural anaesthesia were associated with nerve injuries. Significant associations were also found with the following surgical specialities: Neurosurgery, cardiac surgery, general surgery, and orthopaedic surgery.
◊ CONCLUSIONS:
To our knowledge, this is the largest number of consecutive patients ever reviewed for all types of perioperative nerve injuries. More importantly, this is the first study to identify associations of nerve injuries with hypertension, anaesthetic modality, and surgical speciality.
◊ Reviewed by A. Borgeat, MD, PhD
Professor, chief of the department,
Orthopedic University Hospital Balgrist, Zurich, Switzerland
Perioperative peripheral nerve injury is one of the most feared anaesthetic complications for the patient, the surgeon, and the anaesthesiologist since the healing process may take weeks, months or even years. Welch et al [1] undertook a retrospective analysis of 380,680 cases between 1997 and 2007 to assess the incidence of this complication and to identify patient characteristics, surgical procedures or co-morbidities which could be associated with this complication.
Perioperative nerve injury was defined as a new (within 48 h) sensory and/or motor deficit in any patient who had been sedated or anaesthetized. Injuries caused by the surgical procedure itself were excluded. Data were collected from three different sources: The Department of Anesthesiology’s QA database, the department’s CC database and the institution-wide outpatient and medical diagnoses and billing codes database.
The main findings were first, the incidence of perioperative peripheral nerve injury was very low (0.03%) and second, hypertension, tobacco use, and diabetes mellitus were found to be significant risk factors. General and epidural anaesthesia, but not peripheral nerve block were associated with nerve injury. Neurosurgery, cardiac surgery, general surgery, and orthopaedic surgery were also significantly associated with perioperative nerve injury.
Some of these findings confirmed those of previous studies [2,3], but others such as the association of perioperative nerve injury with hypertension or its lacking association with regional anaesthesia were new and unexpected [4]. However, the results of this work, although interesting, should be interpreted with caution. First, the definition of perioperative nerve injury was limited to any new sensory and/or motor deficit within 48h. This does not match clinical reality since postoperative neuropathy, as stated by the authors, can be delayed and observed at later times [5]. Therefore, the incidence of 0.03% is most likely underestimated. Prospective studies using electromyographic means have reported incidences between 0.2 – 0.4% [5,6] which is probably more realistic. Unfortunately, due the retrospective design of the study the status of the peripheral nervous system prior to surgery is unknown. This would be important information as subclinical neuropathy was shown to be a risk factor [7]. It is a pity that the study design does either not allow an assessment of the long-term outcome of patients with new sensory and/or motor deficits. This is of great concern as the duration of the deficit is a key element to grade the severity of the damage. Moreover, some blocks may have a “physiological” action lasting between 24 to 36 h. These cases would be misclassified as complication. The study definition of perioperative nerve injury excludes all catheter techniques (neuraxial and perineural). This is a subgroup of patients whose neurological outcome would have been interesting. Another weakness of the study is the absence of any electroneuromyographic investigation or documentation. Such assessments are of great importance in this setting as they provide information on the location of the injury, the severity of the damage, and the long-term prognosis [8].
The association between perioperative peripheral nerve injury and hypertension is intriguing. However, additional information would be mandatory to understand this. There are many different types of hypertension, some are “essential” whereas others are secondary to other diseases such as diabetes. However, the type of hypertension is not specified in the manuscript and it should be clarified whether cases of hypertension may also have had diabetes or vice versa. It would also be crucial for the clinician to know whether the hypertension was under control or not. This should be taken into account before considering hypertension per se as risk factor. Dealing with diabetes, a retrospective study conducted by Hebl et al [9] was not able to demonstrate any worsening of polyneuropathy after various types of neuraxial blocks.
In summary, the authors accomplished a huge amount of work by analysing 380,680 cases. However, despite this large number of patients, the results of this study should be taken with great caution since its methodology has important limitations, which do not enable indisputable conclusions. Large well-documented studies are needed to have a better understanding of this problem.
◊ REFERENCES
[1] Welch MB, Brummett CM, Welch TD, Tremper KK, Shanks AM, Guglani P, Mashour GA: Perioperative peripheral nerve injuries: a retrospective study of 380,680 cases during a 10-year period at a single institution. Anesthesiology 2009; 111: 490-7
[2] Jones HD: Ulnar nerve damage following general anaesthetic. A case possibly related to diabetes mellitus. Anaesthesia 1967; 22: 471-5
[3] Massey EW, Pleet AB: Compression injury of the sciatic nerve during a prolonged surgical procedure in a diabetic patient. J Am Geriatr Soc 1980; 28: 188-9
[4] Brull R, McCartney CJ, Chan VW, El-Beheiry H: Neurological complications after regional anesthesia: contemporary estimates of risk. Anesth Analg 2007; 104: 965-74
[5] Borgeat A, Ekatodramis G, Kalberer F, Benz C: Acute and nonacute complications associated with interscalene block and shoulder surgery: a prospective study. Anesthesiology 2001; 95: 875-80
[6] Capdevila X, Pirat P, Bringuier S, Gaertner E, Singelyn F, Bernard N, Choquet O, Bouaziz H, Bonnet F: Continuous Peripheral Nerve Blocks in Hospital Wards after Orthopedic Surgery: A Multicenter Prospective Analysis of the Quality of Postoperative Analgesia and Complications in 1,416 Patients. Anesthesiology 2005; 103: 1035-1045
[7] Blumenthal S, Borgeat A, Maurer K, Beck-Schimmer B, Kliesch U, Marquardt M, Urech J: Preexisting subclinical neuropathy as a risk factor for nerve injury after continuous ropivacaine administration through a femoral nerve catheter. Anesthesiology 2006; 105: 1053-6
[8] Guerit JM, Amantini A, Amodio P, Andersen KV, Butler S, de Weerd A, Facco E, Fischer C, Hantson P, Jantti V, Lamblin MD, Litscher G, Pereon Y: Consensus on the use of neurophysiological tests in the intensive care unit (ICU): electroencephalogram (EEG), evoked potentials (EP), and electroneuromyography (ENMG). Neurophysiol Clin 2009; 39: 71-83
[9] Hebl JR, Kopp SL, Schroeder DR, Horlocker TT: Neurologic complications after neuraxial anesthesia or analgesia in patients with preexisting peripheral sensorimotor neuropathy or diabetic polyneuropathy. Anesth Analg 2006; 103: 1294-9
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