Monitoring to prevent brachial plexus injury

MR Thatte 
 Department of Plastic Surgery, Bombay Hospital & Research Center, Mumbai, Maharashtra, India

Correspondence Address:
Prof. M R Thatte
Department of Plastic Surgery, Bombay Hospital & Research Center, Mumbai, Maharashtra
India

Full Text

Brachial plexus injury (BPI) in hand surgery practice is typically caused by road traffic accidents involving young men on two wheelers and this occurs in approximately 90% of cases. [1] Iatrogenic injury caused by inadvertently cutting the nerves typically occurs during a lymph node biopsy in the posterior triangle of the neck or surgery for torticollis (data on file). A review of PUBMED (as on 5 July 2014) threw up several articles discussing the issue. The major specialty involved is cardiac surgery the cause for which is retraction of the median sternotomy exerting pressure on the plexus at the level of the first rib. [2] The second most important cause is position. Typically, abduction of the arms at 90 degrees or more causes traction of the plexus particularly C8T1 roots causing injury. [3],[4],[5],[6] In liver surgery two papers had a differing perspective. [7],[8] One is a case report [7] which primarily talks of arm position; the other [8] is a series of 120 cases with an incidence of 5.8%. The paper interestingly also has left sided and bilateral cases.

In the brief report in this issue of the journal by Karna et al., the authors postulate that injury is caused by compression, again at the level of the first rib (thoracic outlet) due to the application of the Thomson retractor. [9] Indirect injury as described in this paper is much rarer but not entirely unknown. While this is much like the mechanism in the cardiac cases, there are some key differences. First all cases were exclusively right sided (right lobe of liver was being operated upon and the retractor was on the right side). Secondly, the authors had meticulously avoided arm abduction, thus eliminating one important potential cause of palsy in long surgeries with poor arm placement. Thirdly, their series has involvement of multiple roots and not just C8T1 as seen with poor arm positioning. However, the fact that one patient went on to require fasciotomy and had residual nerve deficit in the long term is disconcerting, and as the authors point out there is need for greater vigilance.

Most indirect BPI cases recover because they are caused by temporary compression which leads to (in this case) demyelination and a Sunderland type [10] I or II injury, both of which usually recover naturally. This is borne out by most reports cited above in the literature. If the compression has also caused a vascular compromise then compartment syndrome and more serious consequences can follow as noted in the present series under discussion in case no. 2.

The best treatment for this injury is prevention. However, since the retractor use cannot be avoided monitoring is probably remains the key. In median sternotomy, the literature has shown that lower application of the retractor on the sternum significantly reduced compression. [3] The other steps include (1) avoiding hyper abduction of arms during prolonged surgery, (2) monitoring vascular compromise with arterial line pressure measurements and pulse oximetry and (3) monitoring nerve function with intraoperative electro physiology study. [10],[11]

If the injury occurs despite best practices, I would recommend an initial period of conservative therapy for 3 weeks, except where vascular issues or compartment syndrome is suspected, or there is suspicion that the nerve itself is inadvertently cut (not applicable to liver surgery). After 3 weeks, electro diagnostics (Edx) should be performed. An Edx performed prior to 3 weeks yields very poor information since Wallerian degeneration [12],[13],[14] ; is not complete and the information is not reliable. In case of Sunderland type I injury nothing further needs to be done as recovery is usually spontaneous and full. If axonotomessis is suspected it is best to refer the person to a Hand surgeon dealing with BPI for further management. Early referral can potentially result in good timely treatment and good recovery.

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