Length–tension relationship of the posterior deltoid to triceps transfer in C6 tetraplegic patients

Abstract

We assessed the length-tension relationship of the posterior deltoid to triceps transfer in 8 tetraplegics (n = 11 transfers) and compared the results to the length-tension relationship of the normal triceps measured in a check sample composed of 9 able bodied, right handed women. We designed a device to lock the arm and forearm and used a force transducer to assess the torque output isometrically. The muscle was tested at 6 different lengths (130, 110, 90, 70, 45 and 0° of elbow flexion) with the shoulder abducted at 90°. As expected, the transfer behaved differently from the normal triceps. The mean maximum torque recorded was 7. 8 Nm in patients while it was 27 Nm in the check sample. When compared, the absolute values (ie values expressed with a dimension of torque) were significantly different between groups (0. 00001 < P < 0. 002). The expression of this relation (ie the relative values expressed as percentage of maximum values) revealed significant statistical differences (p < 0. 002) at 90 and 70° of elbow flexion; the peak torque was recorded at 130° in patients while it was recorded at 110° in the check sample, with a plateau between 110° and 70°. On the other hand, if the length-tension relationship was fairly similar among subjects of the check sample, it exhibited tremendous differences among patients; it seemed that initial tension given by the surgeon represented a variable difficult to control without a device dedicated to that task.

Restoration of elbow extension via functional electrical stimulation in individuals with tetraplegia

“…The average elbow moments produced by persons who have had a posterior deltoid to triceps tendon transfer (Figure 4) are lower than those reported by others [2,3]. This may be due partially to injury level.…”

“…The variation in elbow extension moment with elbow angle (Figure 4) is most likely due to the normal lengthtension properties of the triceps and to the variation in moment arm as the elbow angle changes, since the shape of the curve is similar to that of able-bodied subjects [3,27]. It is also possible that the distance between the electrode and nerve could vary as the triceps is stretched, which would affect the excitation of the nerve.…”

“…Tendon transfers, orthoses, and functional electrical stimulation (FES) are interventions that have been used to address this problem. In the tendon transfers typically used to provide elbow extension, the distal tendons of either the posterior deltoid or biceps muscles are transferred to the triceps muscle [1][2][3][4][5][6]. While tendon transfers have the advantage of being always available, they require an accessible voluntary muscle that has sufficient strength and they require the recipient to learn a new muscle activation pattern.…”

Upper limb reconstructive surgery uptake for persons with tetraplegia in New Zealand: a retrospective case review 2001–2005

“…As this was a clinical notes audit on discharge information, it is unknown whether these people were offered the opportunity to be assessed but declined, or were never offered the opportunity. The average length of time between injury and surgery of 20 months is earlier in NZ compared with other countries such as Spain (34 months), 14 France (46.1 months) 15 and within the United States (34-50 months depending on the centre). [16][17][18] There are a number of plausible explanations for these observed differences between NZ and other countries.…”

Improved kinematics of unrestrained arm raising in C5–C6 tetraplegic subjects after deltoid-to-triceps transfer

“…The oldest of these used in tetraplegic subjects, the transfer from the posterior deltoid to the triceps, has been extensively studied. [2][3][4][5][6][7] Another method that was initially described for restoring elbow extension in subjects with peripheral paralysis uses the biceps brachii. 8 This has been modified to avoid radial paralysis.…”