Bilateral split latissimus dorsi V–Y flaps for closure of large thoracolumbar meningomyelocele defects

A 2-month-old full-term female infant was referred to our clinic with a 12×10 cm thoracolumbar meningomyelocele (Fig. 1) . There was also a pronounced kyphosis. The child had flaccid paralysis of both lower extremities. Watertight dural closure over the exposed neural plate was performed by the neurosurgical team.

Two oblique inclined triangular V–Y flaps were designed bilaterally based supero-lateral to the spinal defect. The lateral tip of the flap extended superiorly beyond the superior border of the latissimus dorsi (Fig. 2) . The incision was started at the distal line of the triangle, from the superior border of the latissimus dorsi muscle including fascia and reached infero-laterally deep to the thoracolumbar fascia. The dissection was maintained under the latissimus dorsi to its anterior border. Then the latissimus dorsi muscle was split under the marked skin flap by sharp dissection from lateral border to the midline. The incision on the medial border of the flap, ended just over the muscle and the dissection was continued in the plane between the latissimus dorsi and skin, in order to preserve the medially based split latissimus dorsi muscle, which includes thoracic and lumbar segmental arteries. The other perforating vessels on the lateral flap line were cauterized and divided in the process to achieve adequate infero-medial transposition and advancement. The split latissimus dorsi flaps based on the lower thoracic and lumbar perforator arteries were elevated bilaterally and advanced toward the midline with minimal tension (Figure 3, Figure 4) . The donor sites were closed primarily in an inclined V–Y fashion with no difficulty. During the first postoperative week, the patient was kept in the prone position, until healing was complete. The back wound healed uneventfully, we encountered no major complications related to the surgery and the child was discharged on the second postperative week. At four months follow up there were no complications (Fig. 5) .

Neural-tube defects result from a failure of the spinal tube to close during the first month of gestation, and vary in severity from anencephaly to occult spina bifida. The etiology of spinal-tube defects is multifactorial; genetic and geographical factors, low socioeconomic level and folic-acid deficiency have been implicated. The lumbosacral area is the site of approximately three-quarters of cases. The neurological deficit depends on the level of the malformation.^{,  ,} 

Infection-free closure is the key in reconstruction of meningomyelocele. Various methods have been suggested for the closure of meningomyelocele. In small defects, a direct approximation of the margins without tension is possible with uncomplicated healing. In large defects, however, to avoid suture line tension, advancement flaps, bipedicled flaps, local transposition flaps, the double Z-plasty, rotation flaps, and Limberg flaps have all been used successfully in achieving closure of large meningomyelocele defects. These flaps, however, require extensive undermining of the skin and have an inherently greater risk of wound edge failure than muscle flaps. In addition, local skin flaps do not provide the same amount of padding that muscle flaps do. Because myelomeningocele coverage is possible by direct closure in almost 75% of cases, only large defects (>8 cm) will require a more complex procedure. Mustardé suggested closure with paraspinous musculo-osseous tissue for covering the neural elements. Moore et al used a bilateral bipedicled advancement flap for closure meningomyelocele defects. While McCraw et al described the use of the latissimus dorsi myocutaneous flap bilaterally without lateral relaxing incisions for thoracolumbar defects, Ramirez et al reported a method for the reconstruction of large thoracolumbar and lumbosacral meningomyelocele defects in which latisssimus dorsi and gluteus maximus myocutaneous units are advanced medially and reapproximated in the midline. Hayashi et al used an entire latissimus dorsi V–Y flap and Thomas in 1993 recommended island fascial or musculocutaneous flap for closure a large meningomyelocele. Finally, Lapid et al described the random bilobed flaps for meningomyelocele reconstruction.

Although these other methods have been suggested, we believe that our technique has several advantages. This procedure provides a reliable, well-vascularized soft-tissue coverage over the neural repair with minimum donor-site morbidity. The flaps can be designed in an oblique inclined fashion according to the natural direction of the muscle fibers and transposed/advanced easily from the supero-lateral region, even in a large meningomyelocele defect. The extent of dissection with our technique is moderate. No relaxing incision or backcuts are needed. The flaps are well vascularized and also provide good soft-tissue padding over the neural repair. Briefly; in our technique, while the muscle was included in the flap on the lateral side, the medial side was planned to include only the skin incision over the latissimus dorsi muscle to preserve the perforating thoracal and lumbal arteries, supplying the musculocutaneous flap. The donor sites can be closed primarily without any difficulties in a sliding semi-circle fashion, and no skin grafts are needed. Transfer of the split latissimus dorsi muscle in this way merely redefines the muscle origins and is unlikely to cause any significant functional deficit especially for transferring paraplegic wheelchair-bound patient, especially, since VanderKolk et al suggested that removal of the latissimus dorsi muscle does not functionally impair strength or range of motion in the upper extremity. The muscles of the gluteal region can be spared for later reconstruction.

Bilateral sliding V–Y advancement–transposition flaps supplying thoraco-lumbal segmental arteries and also including medially based split latissimus dorsi muscle, are thought to be an effective and safe option for the reconstruction of the large meningomyelocele defects.