Manipulative treatment of carpal tunnel syndrome: biomechanical and osteopathic intervention to increase the length of the transverse carpal ligament.

To quantify the amount of transverse carpal ligament (TCL) elongation in response to osteopathic manipulation or sustained load bearing (or both), a study involving seven cadaver limbs was conducted. Distances from the trapezium to the hamate (distance A) and from the scaphoid to the pisiform (distance B) were measured in five mounted cadaver limbs during and after the limbs bore the weight (2 newtons [N] to 4 N) for 2 several-hour periods. A several-hour period occurred between the weight bearing to assess recoil. Distances A and B were measured before and after the limbs were manipulated, according to previously described techniques, as well as with a new maneuver, termed the "guywire" technique. Two dissected limbs also were subjected to further weight bearing, this time increased to 8 N. Greater weight loads produced greater lengthening of the TCL, and recoil after removal of weight loads was slower than recoil after manipulation. Manipulation was more effective than weight loading for increasing distance A (distal canal), but weight loading generally was more effective than manipulation for increasing distance B (proximal canal). The guywire manipulation combined with direct transverse extension appeared to have the greatest impact on lengthening the TCL distally. These results show promise for the effective use of manipulation and load bearing for TCL elongation and nonsurgical relief of pressure on the median nerve in patients with carpal tunnel syndrome.