Resurfacing of thumb-pulp loss with a heterodigital neurovascular island flap using a nerve disconnection/reconnection technique

A Review and Meta-analysis of Adverse Events Related to Local Flap Reconstruction for Digital Soft Tissue Defects

We reviewed the current literature to estimate incidence rates for adverse events with pedicled flaps in the hand. We identified 241 different studies reporting adverse events for 6693 flaps. The average incidence rate was 5.4% and total or partial loss of flap constituted 65% of all reported complications. Flaps with reverse or perforator-based flow may be more prone to vascular complications compared with flaps with antegrade flow or skin pedicle. The incidence rates were acceptable in all flaps (1%-10%) and thus the flap can be chosen primarily based on considerations other than risk of adverse events.

Modified Heterodigital Neurovascular Island Flap for Sensory Reconstruction of Pulp or Volar Soft Tissue Defect of Digits

PURPOSE

We report the efficacy of a modified heterodigital neurovascular island flap innervated by the dorsal branch of the proper digital nerve and the proper digital nerve, for repairing either pulp or volar defects in the fingers.

METHOD

We repaired 14 digits of 14 patients who had a complex defect involving soft tissue and digital nerve in the pulp or volar surface of the digit using the modified heterodigital neurovascular island flap. Cases were divided into 2 groups: a pulp defect group including 5 thumbs and 1 little finger; and a volar defect group with a digital nerve defect, involving one thumb, 3 index and 3 middle fingers, and one ring finger. At the recipient site, nerve stumps of the PDNs in the pulp defect group were coapted with the proximal ends of the dorsal branch of the PDN and the proper digital nerve in the flap. The distal and proximal ends of the PDN in the flap were intercalated into the defect of the PDN in volar defect group, and the proximal end of dorsal branch of PDN in the flap was also coapted to the proximal end of the proper digital nerve of the recipient finger. At the donor site, the defect of the proper digital nerve was repaired with nerve graft harvested from the proximal portion of the dorsal branch of the same proper digital nerve, and a full-thickness skin graft covered the donor site.

RESULTS

All flaps and the skin grafts of the donor site survived completely. At the final follow-up, 9 of 14 flaps had a static 2-point discrimination result below the normal threshold (< 6 mm).

CONCLUSIONS

The modified heterodigital neurovascular island flap is a useful and reliable treatment option for a digital pulp or volar defect, especially when the digital nerve defect requires repair.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Anatomy of the direct small branches of the proper digital nerve of the fingers: a cadaveric study

BACKGROUND AND AIM

The purpose of this study was to evaluate the anatomical constancy of the direct small branches of the proper digital nerve.

METHODS

A total of 208 digital nerves of the index, long, ring, and little fingers from 13 cadavers were studied. For each digital nerve, the number of direct small branches was counted at the proximal and middle phalanx levels. In addition, the diameter of these branches was measured at the level of the branch bifurcation. We also measured the diameter of the proper digital nerve at the level of the distal interphalangeal (DIP) joint.

RESULTS

The direct small branches of the proper digital nerve were anatomically constant among the index, long, and ring fingers. The average number of direct small branches was 2.7 at the proximal phalanx level and 2.3 at the middle phalanx level. At the level of the DIP joint, the average thickness of the proper digital nerve was 0.85 mm in the index finger, 0.84 mm in the long finger, 0.72 mm in the ring finger, and 0.49 mm in the little finger.

CONCLUSION

In this study, we verified the anatomical constancy of the direct small branches of the proper digital nerve. The size of these branches at the proximal phalanx level was similar to that of the corresponding proper digital nerve at the level of the DIP joint. Therefore, these nerve branches at the proximal phalanx could be applied to the creation of various sensate flaps for the reconstruction of the fingertip injuries.

Innervated Lateral Middle Phalangeal Finger Flap for a Large Pulp Defect by Bilateral Neurorrhaphy

BACKGROUND

The dorsal middle phalangeal finger flap is a reliable flap. However, it requires skin grafting on the whole surface of the dorsum of the middle phalanx of the donor finger for an exposed extensor tendon and leaves a conspicuous contour deformity at the donor site. In an effort to overcome this problem, the authors have been using a heterodigital innervated lateral middle phalangeal finger flap for resurfacing sizable defects of the pulp.

METHODS

Flaps were designed on the lateral ulnar side of the middle finger for five thumb defects and the ring finger for two little finger defects. To provide sensation to the flap, one nerve fascicle from the direct small branches of the proper digital nerve after interfascicular dissection (palmar aspect of the flap) and the dorsal branch of the proper digital nerve (dorsal aspect) were identified and sectioned proximally, leaving a 1-cm nerve tail attached to the flap.

RESULTS

These flaps provided sensate coverage with static two-point discrimination values of approximately 6 mm. Donor finger morbidity was minimal, and pulp sensation in donor fingers was normal in all cases. No donor finger cold intolerance was reported in this series.

CONCLUSIONS

This described flap supplies glabrous skin of nearly normal sensibility. One nerve fascicle from the direct small branches of the proper digital nerve and the dorsal branch of the proper digital nerve were used for maximal sensation. Donor fingers are cosmetically better than those of dorsal middle phalangeal finger flaps because the grafted skin is hidden by an adjacent finger.

Venous Supercharging of Heterodigital Artery Flap

BACKGROUND

The heterodigital artery island flap is a popular method of reconstruction for finger defects. Postoperative venous congestion is a common problem.

METHODS

The authors present a technique to augment venous drainage of the flap. Briefly, the flap is harvested along with a dorsal vein that is then anastomosed to a recipient vein in an end-to-end fashion, after flap transfer and insetting. Using this technique, seven patients were operated on, ranging in age from 5 to 35 years (average age, 23 years).

RESULTS

All flaps survived with no postoperative flap congestion, fully satisfying the reconstructive requirements. By this modification, skeletonization of the digital artery of the flap pedicle is safe if that approach is preferred, since there is no need to harvest periarterial fat for venous drainage.

CONCLUSIONS

Providing good harmony with conventional methods and microsurgery, inclusion of a vein with the heterodigital artery island flap allows a more reliable and safer reconstructive choice for finger defects. Such a modification converts the unconventional venous circulation of the heterodigital artery island flap to a more physiologic one.

Specific flaps for the thumb

This article illustrates the use of local and distant flaps for the reconstruction of the thumb. The flaps available for thumb reconstructions, particularly of small defects, are often similar to those used in the fingers. However, they are rarely identical and have usually required modification to the particular needs of the thumb. These flaps and their modifications are, perhaps, as important as the few classic flaps used in larger thumb reconstructions, as many defects of the thumb are small and only a few are large. This article attempts to address all of these needs of thumb reconstruction, indicating when small flaps are suitable and when more extensive reconstructions are necessary.

Sensory function of the neurovascular island flap in thumb reconstruction: comparison of original and modified procedures

A study was conducted to examine the sensory function of thumbs that were reconstructed using 2 procedures: the original Littler neurovascular island flap (NVIF) procedure and a modification of the NVIF procedure in which the divided nerve of the transferred island flap is sutured to the original nerve of the thumb. Twenty-one patients with a mean follow-up period of 4.6 years were examined. Nine patients were treated with the NVIF procedure and 12 with the modified NVIF procedure. Paresthesia was observed more frequently in the patients treated with the original NVIF procedure. The Semmes-Weinstein test and the static and moving 2-point discrimination examinations showed no significant difference between the 2 groups. The pulp writing test showed significantly better results for the patients treated with the modified NVIF procedure. The transferred pedicle flap was fully recognized as representing the thumb in the modified procedure. In the original procedure, however, the sensibility of the transferred pedicle flap was recognized as coming from the thumb in only 61% of the cases; furthermore, the original procedure carried an additional disadvantage in that sensibility of the transferred pedicle flap was recognized as coming from both the donor and recipient sites.