Assessment of the Forearm Tendon Transfer with Irreparable Radial Nerve Injuries Caused by War Projectiles

Abstract

Introduction: Injuries to the radial nerve can occur at any point along its anatomical route, and the etiology quite varies. A particular entity are war injuries of the extremities, which have high morbidity but low mortality. After irreparable radial nerve injury, the only treatment is tendon transfer (if we neglect arthrodesis) with over then 40 methods. Four tendon transfers are considered as better than the other and two of them are the subject of our article flexor carpi radialis (FCR) and flexor carpi ulnaris (FCU). Aim: To evaluate the ultimate functional results of forearm tendon transfers for irreparable radial nerve damage caused by war injuries and indicate the better operative treatment choice in accordance with the evaluation schemes. Methods: This retrospective research included 40 patients with isolated irreparable radial nerve damage. Patients were operated from 1993 to 1996. The follow-up period is from 3.5 to 11.5 years (until 2007). Twenty patients were operated using FCR tendon transfer method and twenty patients were operated using FCU tendon transfer method. The surgery was performed at the Clinic for Reconstructive and Plastic Surgery, Clinical Center University of Sarajevo. Three score evaluation schemes were used: Zachary, Neumann Pertecke and Tajima scheme, along with subjective evaluation of treatment. Results: Measured by the Zachary Evaluation Scheme, the overall score in patients undergoing FCR tendon transfer is 92.25%. In patients undergoing FCU tendon transfer, the total score was 82.20%. The total result of all 40 operated patients was 87.25%. The Zachary evaluation scheme showed a significant difference between FCR and FCU results by tendon transfer (p <0.05) in favor of the FCR tendon transfer. Tajima scheme proved a statistically significant difference between the two tendon transfers (p = 0.024), also in favor of FCR tendon transfers. Conclusion: Forearm tendon transfer is a relevant method to compensate for the loss of function of the wrist, fingers and thumb extensions as a result of irreparable damage to the radial nerve. FCR tendon transfer provides better functional results than FCU tendon transfer in irreparable radial nerve damage. The time elapsed from the injury to the performed surgery of the tendon transfer has no effect on the final functional result. There is no surgical tendon transfer procedure that can be recommended as a standard for any patient. Practically, the surgeon must tailor the surgery to the patient's needs. It is necessary to develop a unique and generally accepted evaluation scheme for the results of tendon transfers that will enable comparisons of results achieved. Both methods can be used for irreparable damage of radial nerve due to any etiology.

New Functional Evaluation Scheme - Modality of the Results of Forearm Tendon Transfers Evaluation in Cases of Irreparable Radial Nerve Injury

“…The etiology of radial nerve (RN) injuries is usually direct, rarely, indirect trauma. Sharp lacerations usually result in nerve intersection and firearm injury by neuropraxia or axonotemesis, extremely rarely by neurothesis (1)(2)(3)(4)(5)(6). The incidence of RN injury associated with humeral fracture is from 1.8% to 16% (1)(2)(3)(4)(5)(6).…”

“…Sharp lacerations usually result in nerve intersection and firearm injury by neuropraxia or axonotemesis, extremely rarely by neurothesis (1)(2)(3)(4)(5)(6). The incidence of RN injury associated with humeral fracture is from 1.8% to 16% (1)(2)(3)(4)(5)(6). In the case of firearm war injuries, the incidence of injury to the RN and upper arm is higher, and usually with a frac-ture of humerus , it is a neuropraxia of the RN, and in peacetime injuries, it is more often isolated radial nerve injuries (4,5).…”

“…The most common clinical presentation after radial nerve injury is represented by paralysis of all ex- tensor muscles of the hand and fingers (a typical "wrist drop"). RN injuries usually occur below the branch for the triceps muscle of the upper arm, and extension of the elbow joint is possible in such cases (2,3,5). Traditionally, radial nerve palsy is divided into high and low types.…”

“…Traditionally, radial nerve palsy is divided into high and low types. It is necessary for the surgeon to distinguish complete radial nerve palsy from deep branch paralysis RN (low type,interosseal nerve palsy) (1,2,3,5). There are two ways to treat radial nerve injury: a) Nerve repair (neurorraphy -primary, primary delayed and secondary) and rarely neurolysis, usually neuroplastic in the sense of a (sural) nerve transplant to replace a nerve defect that is a secondary procedure; b) Tendon transfer (TT) of the forearm.…”

“…A tendon transfer is the separation of a tendon or tendon insertion of a muscular tendon unit and its reinsertion to another tendon or bone to compensate for lost function (3,8,9). Irreparable damage to the radial nerve was considered a condition of failure of function when surgical treatment from the aspect of medical standards would not provide a motor response after reconstruction due to: local finding (defects of the radial nerve over 10 cm with a neat soft tissue cover on the path of expected sprouting, defects of the radial nerve over 8 cm if these are high damage combined with large skin defects in the expected RN growth path) and elapsed time to the expected reinnervation.…”