CC BY-NC 4.0 · Arch Plast Surg 2015; 42(04): 494-497
DOI: 10.5999/aps.2015.42.4.494
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Innervated Free Groin Flap

Jose Couceiro
Hand Surgery Unit, Department of Orthopaedics, Povisa Hospital, Vigo, Spain
,
Marcos Sanmartin
Hand Surgery Unit, Department of Orthopaedics, Povisa Hospital, Vigo, Spain
› Author Affiliations

The pedicled groin flap as been extensively used for the reconstruction of soft tissue injuries of the hand [[1]]. Two main disadvantages have limited its use: the hand must be attached to the groin region for three weeks and the flap does not have sensitivity, which is critical to the function of the hand. In 1973, Daniel and Taylor [[2]] described the free groin flap, obviating the need for a second procedure, improving patient comfort, and allowing early rehabilitation protocols.

In 1977, Joshi [[3]] described a technique involving "neural repair for sensory restoration of a groin flap." In order to obtain innervation, he harvested the lateral cutaneous branch of the twelfth thoracic nerve with the flap and carried out an end-to-end repair with an available sensory nerve branch in the operative field. The procedure was designed for a pedicled groin flap, as the nerve enters the flap opposite to the pedicle. This creates problems in adapting this technique to a free groin flap, because it is difficult to find a donor nerve at the distal aspects of the wound.

We describe the use of an innervated free groin flap to repair a post-traumatic soft tissue defect at the volar aspect of the hand. To the best of our knowledge, this is the first reported case of such a procedure.

A 46-year-old woman sustained trauma to her right hand with a conveyor belt, producing an injury to the soft tissues of the palm and comminuted fractures of the bases of the proximal phalanxes of the long, ring, and small fingers. All of the digits except for the thumb were ischemic at her arrival to our emergency department, which occurred eight hours after the initial trauma. Three revascularization attempts with vein grafts were unsuccessful. Reperfusion was only achieved for the palmar aspect of the index finger up to the distal interphalangeal joint.

Four days later, the patient returned to the operative room for debridement of devitalized tissue at the palm and amputation of the small finger through the metacarpal neck and fingertips of the index, middle and ring fingers. The palmar aspect of the long and ring fingers was also excised. A free groin flap, measuring approximately 10 cm × 6 cm, was obtained from the contralateral side for coverage. The lateral cutaneous branch of the twelfth thoracic nerve was harvested and was coapted with the ulnar collateral nerve of the long finger ([Fig. 1], [2], [3]). The flap required two additional debulking procedures along with syndactyly release; these debulking procedures were performed following the first signs of re-innervation. The debulking procedures were performed in a very specific fashion, starting opposite to the nerve coaptation area and slowly progressing towards it. We stopped 1 cm from the nerve coaptation area; in an attempt to preserve the nascent nerve branches on the flap we focused on the deep fat lobules and tried to preserve the smaller superficial fat lobules [[4]]. Recovery of sensation was observed two months after the main procedure.

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Fig. 1 A free groin flap was elevated to cover the defect. The lateral cutaneous branch of the twelfth thoracic nerve was harvested along with the flap and was sutured in an end-to-end fashion with the ulnar collateral nerve of the long finger.
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Fig. 2 Line diagram showing the anatomy of the donor area. The lateral cutaneous branch of the twelfth thoracic nerve can be seen entering the flap proximally.
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Fig. 3 Line diagram showing the surgical technique including the vascular anastomosis and the nerve coaptation sites.

One year later, the results of the Semmes-Weinstein monofilament test were 4.31 (2 g) on her long finger and 5.07 (10 g) on her ring finger. She was able to discriminate hot and cold temperatures, but had no static or dynamic two-point discrimination. Her grip strength, as measured with a Jamar dynamometer (Baseline Instruments, White Plains, NY, USA) was 10 kg in her right affected hand and 28 kg in the uninjured hand. The patient reported no cold intolerance or discomfort ([Fig. 4], [5]).

In order to innervate a free iliac flap, the surgeon must address the fact that the nerve is located opposite to the pedicle. If preservation of the digital nerves is possible after the early debridement of necrotic tissue at the palm of the hand and digits, neurotisation can be achieved. When the receptor nerves do not reach the distal aspects of the wound, it is also possible to further extend the dissection of the flap and harvest a greater length of donor nerve.

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Fig. 4 Following two debulking procedures, the patient was satisfied with the result.
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Fig. 5 At the latest follow-up, the patient retained protective sensation on the area of the flap as well as functional pinching ability with her uninjured thumb.

According to previous reports describing neurotised pedicled groin flaps, better sensory recovery occurs when a nerve is sutured to a sensory nerve of the groin flap, in comparison to other flaps from the abdomen or the groin without neurotisation [[3] [5]].

In his original article, Joshi [[3]] states that his procedure led to a result of S2+ on the Highet scale. White and Bain [[5]] reported static two-point discrimination of 3 mm two years after resurfacing the dorsal aspect of a thumb.

Nonetheless, conflicting reports exist in the literature regarding sensation recovery in non-innervated iliac or groin flaps. Tare and Ramakrishnan [[6]] described the use of a free mini-groin flap for digital resurfacing and found no recovery of sensation, even with radical thinning of the flap. Pan et al. [[7]] utilized non-innervated free iliac flaps to treat multiple skin defects of the hand and digits, and described an average static two-point discrimination of 15.4 mm in five out of the eight patients after an average of 20.4 months, whereas the remaining patients only exhibited sensation to pressure.

For a non-sensate flap to recover two-point discrimination, a random process of nerve ingrowth must originate from the underlying receptor area. This process can take longer than two years and may be facilitated by thinning the flap. However, secondary debulking procedures can hamper this process. Our patient underwent two debulking procedures, which were not found to affect the recovery of sensation.

We believe that the earlier recovery of sensation, as was observed in our case, may help in the rehabilitation process and avoid complications involving burns, ulcerations, and cold intolerance during the first two years. Yan et al. [[8]] reported the results of innervated versus nonsensate flaps for fingertip reconstruction and concluded that insensate flaps resulted in poorer sensation recovery and significant subjective discomfort in terms of cold intolerance. They also observed a trend for lower grip strength measurements in the nonsensate flap group.

Neurotisation of a free groin or iliac flap, whenever possible, is a relatively simple and worthwhile procedure, since it enables the quicker recovery of sensation and aids in the prevention of the development of cold intolerance and discomfort. Of the many options available for reconstructing moderately sized to large defects of the palm of the hand and fingers, an innervated free groin flap combines a maximally concealed donor area with functional sensory recovery. It was this combination of concealment and functional recovery that prompted us to choose an innervated free groin flap over other reconstructive options for the management of our patient's condition.



Publication History

Received: 19 February 2015

Accepted: 23 April 2015

Article published online:
05 May 2022

© 2015. The Korean Society of Plastic and Reconstructive Surgeons. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonCommercial License, permitting unrestricted noncommercial use, distribution, and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes. (https://creativecommons.org/licenses/by-nc/4.0/)

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