EVALUATION OF TENDON TRANSFER FOR RADIAL NERVE PALSY

Results

This study included 20patients. The mean age of patients in FCR group is33.4±8.8 ,FCU group is38.8±11.4  and FDS group is37.4±11.3years(p-value = 0.58)Table (3).  There were5(55.6%)male and 4(44.4%)in FCR group, 4(66.7%)males and 2(33.3%)females in FCU group and 4(80%)males and 1(20%)female in FDS group(p-value = 0.65)Table (4). 7patients(77.8%)dominant and 2patients(22.2%)non dominant in FCR group, 3 patients (50%) dominant and 3patients (50%) non dominant in FCU group while there were 4patients(80%)dominant and 1 patient (20%) non dominant in FDS group (p-value 0.44)Table (5).

Table 3: Comparison between studied groups as regard age.

Table 4: Comparison between studied groups as regard sex.

Table 4: Comparison between studied groups as regard sex.

Table 5: Comparison between studied groups as regard side.

The wounds healed with first intention with no problems except 2case in group1, 1cases in group2and treated with frequent dressing and healed by secondary intention with no major complications.  Re-education started one month  postoperative and mean follow-up period was 9months, (range 6-12months).

In FCR group , 6 patients( 66.6%) were excellent, 2 patients(22.2%) were good and 1patient(11.1%) was fair.

 In FCU group, 3 patients (50%) were excellent, 2 patients (33.3%) were good and 1patient(16.7%) was fair.

In FDS group , 3 patients (60%) were excellent, 1 patient(20%) was good and 1 patient (20%) was fair. so there is no statistical significant difference in result(p-value > 0.05) between studied groups as regard objective Table (6) and subjective evaluation Table (7). but, regarding donor site morbidity, time of operation, some loss of grip strength, preservation of important moment of flexion and ulnar deviation of the wrist which is important for power grip in working men. easier, quicker and associated with less intra-operative dissection. we found that there is significant difference between the three groups in favor of FCR transfer.

Table 6: Comparison between studied groups as regard objective evaluation.

Table 7: Comparison between studied groups as regard subjective evaluation.

 Figure 7: pre & post-operative result with restoration of wrist, fingers and thumb extension by PT, FCR and PL transfer respectively 6month later.

DISCUSSION

The radial nerve is the most frequently injured major nerve in the upper limb and etiology of its injury is quite varied, As result of its proximity to humeral shaft, as well as its long and tortuous course.⁷

Most authors believe that tendon transfers will result in good outcomes in cases of radial nerve palsy with irreparable damage or reconstruction failure.²

Sunderland recommended that one year is enough to go on tendon transfer if nerve recovery has not happened in this time.⁸

Burkhalter believed that the greatest functional loss in patient with radial nerve injury is weakness in grip and recommended early transfer to eliminate the need for external splint and reduce the period of disability after injury.⁹

There is no consensus on the best method for tendon transfer in patients with radial nerve palsy.¹⁰

Classically,surgeons use different combinations of tendon transfers in order to achieve three major goals in treatment of radial nerve palsy including restoration of finger extension, restoration of thumb and wrist extension in cases of severe radial nerve palsy.⁶

.In early transfer, This was intended as substitute for internal splint during regeneration of the nerve after repair and there are quite acceptable functional results in first weeks after removing plaster splint and patients were able to return to work early than expected  before nerve healing and regeneration had happened.¹¹

The rationale for Jones transfer(FCU to EDC)was amatter of surgeon’s preference and some patients have ulnar deviation of the wrist pre-operatively while Brands(FCR to EDC)transfer was advocated instead of FCU to restore finger extension to preserve FCU which is more important wrist flexor than FCR because normal axis of wrist motion is from dorsal-radial to volar-ulnar.¹²

 Boyes then Chuinard et al;suggested that superficialis tendons, with their greater excursion(70mm),would be better motors for finger and wrist extensors. Their major proof was the fact that amplitude of action and power of wrist flexors is too small to allow simultaneous extension of wrist and fingers.¹³

The FDS transfer was primarily employed as it provides thumb extension independent from wrist and fingers extension, because the FDS control each finger is independent from other fingers. The FDS of the middle finger was preferred as motor for EPL because it provides7cm of excursion, while FCR provides only3cm; therefore, the FDS is more efficient, noting that EPL normally provides5cm excursion.¹⁴

In this study, Significant improvements in wrist and finger extension and hand grip were obtained. These due to good rehabilitation program and optimal intraoperative tensioning of donor tendon to recipient extensor tendon. Re-education of muscle-tendon unit is important part of rehabilitation following tendon transfers.Surgeon and hand therapist should implement patient integrated team approach to improve functional outcome.Following one-month postsurgical splinting and physiotherapy, ranges of motion in MCP,PIP andDIP joints of the fingers were compared between all patients.

The results of statistical analysis showed no significant difference in ranges of motion in respective joints between them. but,regarding the donor site morbidity, the time of operation, some loss of grip strength, preservation of important moment of flexion and ulnar deviation of wrist which is important for power grip in aworking men. easier, quicker and associated with less intra-operative dissection. we found that there is significant difference between three groups in favor of FCR transfer.

As the PTwas used in most patient groups, probably it may be concluded that the most successful result in radial nerve paralysis treatment by tendon transfers will be wrist extension. Limitation of wrist flexion was noted in most of our patients, though actually none had any complaints of it. This must be due to the fact that less wrist flexion is necessary than extension in daily activities and fewer activities need it. We did not measure the power of grip because of lack of equipment. Though surely this is alimitation of the study,it may be considered that power of grip differs among individuals, and even between the two hands in the same individual, both sides cannot be of equal strength,so grip is not a good parameter for comparison.

The fact that none of our patients had any complaints of a reduced power of grip may be due to their accommodation to procedure or to improvement in grip strength.  There is concern about loss of some functions in the hand and wrist after transfer of three tendons. However, some authors believe that a single FCU cannot provide simultaneous wrist dorsiflexion and fingers extension.

CONCLUSION

The tendon transfer is avery successful treatment for irreversible radial nerve paralysis, and result in good functional outcome of wrist and finger extension and power of hand grip. We recommend early transfer at time of nerve repair.Because early transfer reduce the period of disability after injury to  weeks rather than months after nerve repair. We also recommend FCR transfer Because it preserves the important moment of flexion and ulnar deviation of the wrist which is important for power grip in aworking men. Harvest of FCU removes the only remaining ulnar deviator of wrist, resulting in radial deviation, particularly in patients with PIN palsy,the FCR transfer is easier, quicker and associated with less intra-operative dissection.