This study is a cadaveric evaluation of the risk of iatrogenic nerve injury during open sub pectoral biceps tenodesis. This study shows a unicortical technique is safer because a bicortical technique risks injury to the axillary nerve posteriorly

1. Saithna A, Longo A, Leiter J, Old J, Macdonald PM. Southport & Ormskirk Hopsitals, UK, and the Pan Am Clinic, Canada
BACKGROUND
There is increasing evidence to support a subpectoral over a
suprapectoral tenodesis location. Subpectoral tenodesis can be
performed with a variety of different techniques (uni or bicortical button,
tenodesis screw, suture anchors) but none has been clearly demonstrated
to be superior to another with respect to biomechanics or clinical
outcomes. In the absence of high quality evidence to guide the selection
of a particular surgical technique the most important consideration should
be the safety profile of the procedure.
OBJECTIVES
A number of cadaveric studies have evaluated the risk of neurological
injury with subpectoral tenodesis using a bicortical button but there has
been quite some variability in the reported proximity to the major nerves.
Furthermore, in some cases cadaveric and clinical studies have reported
iatrogenic injury and certainly this is a cause for concern. Some of this
variability in reports of proximity to important structures is probably due to
small sample sizes. It is therefore appropriate that further study is
performed to add to this existing data. The aim of this study is to evaluate
the risk of neurological injury from the placement of a bicortical guidewire
during subpectoral biceps tenodesis.
RESULTS
The mean age was 73 years (range 44-96 years) and there was an equal distribution of right and left-sided limbs.
The mean distances from the guidewire to the respective nerves was as follows: axillary nerve posteriorly; 15.7 mm (10-22 mm),
axillary nerve laterally; 18.7 mm (12-22 mm), radial nerve posteriorly; 26.2 mm (16-35 mm), radial nerve medially; 25 mm (16-32
mm), musculocutaneous nerve; 20.1 mm (12-26 mm). The chart below demonstrates the range of proximities to the respective
nerves (AP: Axillary nerve posteriorly, AL: Axillary nerve laterally, RP: Radial nerve posteriorly, RM: Radial nerve medially, M:
Musculocutaneous) in the current study (shaded boxes), compared to the ranges reported in all other published series (lines) [data
included from refs 1-5 below].
The most important finding is that the axillary nerve posteriorly was within 10mm of the guidewire in at least one specimen in our
study and in direct physical contact with the wire in other studies demonstrating a high risk of iatrogenic injury.
CONCLUSIONS REFERENCES
METHODS
The study was awarded health research ethics board approval. 10 fresh
frozen forequarter cadaver specimens with intact distal extremities were
evaluated after being thawed for a minimum of 24 hours.
A 3 cm incision was centred over the lower border of a normally tensioned
pectorals major. The fascia over the coracobrachialis and biceps muscle
bellies was incised and blunt finger dissection was used to identify the
tendon and the bicipital groove. Non-levering retractors were then placed
on bone to clearly expose the intended site of tenodesis. This was located
in the bicipital groove, 1 cm above the lower border of the pectoralis
major muscle. A 2.7 mm guidewire was passed from the bicipital groove
anteriorly to posteriorly, through both cortices, with a trajectory that was
perpendicular to the long axis of the humerus and parallel to the rotational
axis of the forearm. A full, open dissection was then performed to identify
the neurological structures. Digital calipers were used to record the
closest distances from the guidewire to the nerves in their susceptible
locations
Although there has been some disagreement in the literature regarding the
proximity of a bicortical guidewire to the axillary nerve posteriorly, the
results of this study concur with reports from several other authors and
demonstrate that this nerve is at risk of iatrogenic injury when using a
bicortical technique. A unicortical technique avoids this risk and has not
been shown to be inferior biomechanically.
Surgeons should consider a unicortical technique and if they use a
bicortical technique they should be aware of the diameter of button that they
use when evaluating the data reported in this study (distance from
guidewire only reported in this study i.e. button diameter not accounted for)
and the risk of iatrogenic injury.
1.Arora AS, Singh A, Koonce RC (2013) Biomechanical Evaluation
of a Unicortical Button Versus Interference Screw for Subpectoral
Biceps Tenodesis. Arthroscopy 29:638–644
2. Dickens JF, Kilcoyne KG, Tintle SM, Giuliani J, Schaefer RA, Rue
J-P (2012) Subpectoral Biceps Tenodesis: An Anatomic Study and
Evaluation of At-Risk Structures. Am J Sports Med 40:2337–2341
3. Ding DY, Gupta A, Snir N, Wolfson T, Meislin RJ (2014) Nerve
Proximity During Bicortical Drilling for Subpectoral Biceps Tenodesis:
A Cadaveric Study. Arthroscopy 30:942–946
4. Lancaster S, Smith G, Ogunleye O, Packham I (2014) Proximity of
the axillary nerve during bicortical drilling for biceps tenodesis. Knee
Surg Sports Traumatol Arthrosc DOI 10.1007/s00167-014-3214-z
5. Sethi PM, Vadasdi K, Greene RT, Vitale MA, Duong M, Miller SR
(2015) Safety of open suprapectoral and subpectoral biceps
tenodesis: an anatomic assessment of risk for neurologic injury. J.
Shoulder Elbow Surg. 24:138–142
A Cadaveric Assessment Of The Risk Of Nerve Injury During Open
Subpectoral Biceps Tenodesis Using a Bicortical Guidewire
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Distancefromnerve
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AP AL RP RM M