Volume 8, Issue 10, Pages 925-934 (October 2016) High-Pressure Balloon-Assisted Stretching of the Coracohumeral Ligament to Determine the Optimal Stretching Positions: A Cadaveric Study  Sora Baek, MD, PhD, Kyu Jin Lee, PhD, Keewon Kim, MD, Seung-Ho Han, MD, PhD, U-Young Lee, MD, PhD, Kun-Jai Lee, MD, Sun Gun Chung, MD, PhD  PM&R  Volume 8, Issue 10, Pages 925-934 (October 2016) DOI: 10.1016/j.pmrj.2016.02.011 Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Figure 1 (A) The coracohumeral ligament (CHL) is exposed after resection of the coracoacromial ligament. A guide wire (white arrowhead) is inserted under the CHL. (B) Illustrative drawing corresponds to A. (C) A balloon catheter (open arrowhead) is inserted along the guide wire. Co = coracoid process; HH = humeral head; CjT = conjoined tendon of the short head of biceps and the coracobrachialis. PM&R 2016 8, 925-934DOI: (10.1016/j.pmrj.2016.02.011) Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Figure 2 Experimental setup for inflation and deflation of the balloon with intraballoon pressure monitoring. A balloon catheter inserted under the coracohumeral ligament (CHL) is shown in the cadaver image. The balloon catheter was connected to the pressure sensor via a 3-way stopcock, so that the pressure in the tubes could be measured by the sensor. The sensor signal was amplified, digitalized, and received by a personal computer (PC) via an amplifier and data acquisition system (DAQ). The syringe pump was controlled by the same computer through the DAQ. Co = coracoid process. PM&R 2016 8, 925-934DOI: (10.1016/j.pmrj.2016.02.011) Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Figure 3 Measuring pressure increase (ΔPCHL) by the overlying coracohumeral ligament (CHL) to evaluate CHL tightness. A balloon is inflated and the intraballoon pressure is measured in the air (Pair) and then under the CHL (PuCHL). The difference between 2 intraballoon pressures is calculated to achieve ΔPCHL, pressure increase by overlying CHL. The circle, square, and diamond markers are included merely to denote the 3 pressure curves; Pair, PuCHL, and ΔPCHL, respectively. It should be noted that the sampling rate (200 Hz) is far higher than the number of markers. Three time points are marked in the pressure curves when the balloon is deflated (A), almost fully inflated (B), and maximally inflated (C). The timing of the maximum inflation (C) is determined by an abrupt increase in intraballoon pressure in the air. Corresponding photographs are also shown. Co = coracoid process; HH = humeral head. PM&R 2016 8, 925-934DOI: (10.1016/j.pmrj.2016.02.011) Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Figure 4 A typical intraballoon pressure increase (ΔPstr) by directional stretching. After a balloon is inserted under the coracohumeral ligament (CHL) and inflated as far as the fully inflated state (see Methods and Figure 3), intraballoon pressure (Pstr) was monitored during stretching in 5 directions (flexion [FL], extension [EX], external rotation [ER], EX+ER, and EX+ER+adduction [AD]). The ΔPstr of each direction is calculated as the difference between the average baseline pressure and the maximum pressure. PM&R 2016 8, 925-934DOI: (10.1016/j.pmrj.2016.02.011) Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Figure 5 The ΔPstr for 5 stretching directions (flexion [FL], extension [EX], external rotation [ER], EX+ER, and EX+ER+adduction [AD]). ∗P < .05 by post hoc analysis with least significant difference test. PM&R 2016 8, 925-934DOI: (10.1016/j.pmrj.2016.02.011) Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions

Figure 6 Sequential shoulder positions to achieve the maximal stretching position for the coracohumeral ligament from the neutral (A), extension (EX) (B), EX+external rotation (ER) (C), to EX+ER+adduction (AD) (D) positions. PM&R 2016 8, 925-934DOI: (10.1016/j.pmrj.2016.02.011) Copyright © 2016 American Academy of Physical Medicine and Rehabilitation Terms and Conditions