Tendon transfers are well-accepted treatment modality for managing difficult neurological and musculotendinous deficits of upper and lower extremities. Although tendon transfers do not address the sensory element, the motor deficits can be restored in most of the cases. Unlike nerve surgeries, the results following the tendon transfers are very much predictable. Apart from the availability and strength of the donor tendons and suppleness of the joints, the most important technical consideration in the final outcome of the tendon transfer procedures are the tension and the position with which the donor tendon is attached to the recipient tendon. Unfortunately this important step is the least addressed in the literature. Although the tension during the tennorhaphy in tendon transfers may be a subject of personal preference, there must be a mechanism to reproduce the same technique with an option of subtle variation for a given case depending on the factors like ligamentous laxity. Although the authors1 have tried to address this aspect of the procedure in the past, the equipment involved a splint which may not be readily available and hence method was not reproducible. We the authors are describing a method of fabricating the intraoperative splints which can be assembled preoperatively using omnipotent external fixator systems readily available in orthopedic and hand operative theaters.
The methods involved in the fabrication of intraoperative splints utilize the rods, clamps commonly used for the external fixation. For upper limb procedures, we use forearm fixators for making splints and for f procedures on foot, lower limb external fixator can be used (Figs. 1A, B). Ideally the fixator can be customized and fabricated preoperatively and can be autoclaved for aseptic use during the surgery. Depending on the surgery and the surgeon’s preference, the splint for claw correction, opponensplasty, and procedure for wrist and foot drop can be assembled. Generally, position recommended for attachment of donor tendon slip to the lateral slip of the extensor tendon on the dorsum of the proximal phalanges is one of neutral at wrist and 70 degree of flexion at metacarpophalangeal joint with the interphalangeal joints being straight (Figs. 2A, B). The recommended position for opponensplasty is one of neutral position at wrist with thumb in complete palmar abduction and pronation (Figs. 3A–C). And for reconstruction of wrist drop, the position opted by most of the surgeons is one of neutral at wrist, metacarpophalangeal and interphalangeal joints, while attaching the flexor carpi radialis/flexor carpi ulnaris to extensor digitorum communis (Fig. 4A). During the attachment of pronator teres to extensor carpi radialis brevis, the recommended position is neutral position of metacarpophalangeal and interphalangeal joints with wrist being kept in 45 degrees of extension (Fig. 4B).
For the commonly performed tibialis posterior tendon transfer to extensor hallucis longus and extensor digitorum longus in foot drop, the recommended position is 20 to 30 degrees of ankle dorsiflexion (Figs. 5A, B). Because of the size and the strength in the lower limb, we recommend to use the bigger rods and clamps of the fixator while making the intraoperative splint.
The good part of the technique is that it can be customized (fine tuning the angles) and readjusted according to the needs of the operative procedure. Intraoperatively, the limb can be held in the desirable position on the splint using fasteners like crepe bandage and rubber bands (for the thumb).
We have been using these splints in our department during the reconstructive surgeries routinely without any difficulty. It has helped us to reproduce the same position and tension during the procedure and allows subtle adjustments to address lax or tight joints. We have also conveniently avoided the second assistant commonly used during these procedures. This will be appreciated in high output centers with paucity of man power in the operation theater.
Results of tendon transfers both in upper and lower limbs are satisfactory even in the hands of average surgeons. Although technically not very demanding, results largely depend on the tension with which the donor tendon is sutured to the recipient tendon. The appropriate intraoperative positioning of the joints at the time of tenorrhaphy is the key for success of the surgery. Instead of manual positioning by an assistant, an intraoperative splint will go a long way in optimizing the final results.
The splint described by the authors is modular, prefabricated, and autoclavable that can be used in any age group and on both sides. It does not cost anything extra as the splint can be prepared using external fixator system which is easily available in most of the centers. The surgeon can save time if the entire splint can be assembled one day earlier to surgery. It will not only simplify the procedure but also allows the surgeon to work with one less assistant.
To conclude, the splint described above can be a very handy tool and a worthy technical tip to optimize the final results of the important and commonly performed tendon transfer procedures.
1. Kamath BJ, Praveen B. A modular tension adjusting splint for tendon transfers
in reconstructive surgeries and extremities. IJPS. 2006;39:185–188.