Large thoracolumbar meningomyelocele defects: incidence and clinical experiences with different modalities of latissimus dorsi musculocutaneus flap

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1 The British Association of Plastic Surgeons (2004) 57, Large thoracolumbar meningomyelocele defects: incidence and clinical experiences with different modalities of latissimus dorsi musculocutaneus flap Hamdy A. El-khatib* Department of Plastic Surgery and Burns, Hamad Medical Corporation, P.O. Box 3050, Doha, Qatar Received 2 May 2003; accepted 19 December 2003 KEYWORDS Thoracolumbar meningomyelocele; Latissimus dorsi flap Summary In this study, we report a series of large thoracolumbar meningomyelocele (MMS) defects. The total incidence per 1000 live birth is 0.6, the male incidence per 1000 live birth is 0.56, and the female incidence per 1000 live birth is The study was conducted on 23 infants, all suffered from large thoracolumbar MMC defects, and our treatment techniques are modifications of procedures previously described. The timing of surgery ranged between 2 and 5 days after birth, and the follow-up was ranged between 3 and 7 years. Different modalities were used for reconstruction: bilateral proximally based skin island, muscle pedicle latissimus dorsi (LD), myocutaneous flap (seven patients), bilateral bipedicled LD, myocutaneous flaps (nine patients), and distally based skin island, muscle pedicle LD, myocutaneous flaps (seven patients). All the patients tolerated procedures smoothly, and because LD muscle may be important for mobility in a potentially paraplegic wheelchair-bound patient, the author presents some modifications in order to preserve the muscle function. Criteria for flap selection will be discussed. Q 2004 Published by Elsevier Ltd on behalf of The British Association of Plastic Surgeons. There is wide geographic and racial difference in incidence of myelomeningocoeles (MMC). The incidence of MMC varies from 1 per 1000 live births 1 to 0.8 per 1000 live births. 2 In some regions of China, it is reported as high as 8 per 1000 live births. 3 This study reports the incidence in the gulf region (QATAR) as 0.6 per 1000 live births (Table 2). The aetiology of neural tube defects includes factors related to genetic, geographical, low social standard and folic acid deficiency. The neural tube defect results from failure of fusion of the spinal *Corresponding author. address: hamdyel@yahoo.com tube during the first 4 weeks of gestation. The closure of MMC defects aims to preserve the function of the neural tissues and to prevent secondary infection. Hunt and Oakeshott 4 investigated survival, disability, and lifestyles in a complete cohort of adults with spina bifida. They concluded that following the introduction of cerebro-spinal fluid shunts, there was a fourfold increase in survival of babies with open spina bifida, and the mean age of the survivors was 35 years. An audit of reconstructive techniques for the management of open MMCs is, therefore, useful. Luc and Walsh 5 applied delayed skin grafting, S /$ - see front matter Q 2004 Published by Elsevier Ltd on behalf of The British Association of Plastic Surgeons. doi: /j.bjps

2 412 H.A. El-khatib Figure 1 Schematic illustration of different procedures. Mustarde 6 described the use of osteomuscular flap in severe spina bifida in order to build-up the dorsal part of the neural arch. McCraw et al. 7 reported the bilateral bipedicled latissimus dorsi myocutaneus flap, and did not agree about the lateral skin incisions for tension free closure, Moore 8 indicated that relaxing flank incisions were necessary for primary closure without tension on the midline wound. Blaiklock 9 in 1981 used the latissimus dorsi (LD) myocutaneous flap in the repair of spinal

3 Large thoracolumbar meningomyelocele defects 413 Reverse LD muscle flap was reported by Vanderkolk 12 as a case report, and by Scheflan, 13 the blood supply of this flap is also described by Stevenson. 14 Lapid et al. 2 described a bilobed cutaneous flap based superiorly and laterally, with no suture line over the cord closure. In this large series, we report our experience of 23 patients with large thoracolumbar MMC. LD myocutaneus flap was used in varying designs. Anatomical considerations The secondary perforating branches of the posterior intercostal and lumbar arteries enter the latissimus dorsi muscle 3 4 cm from the midline posteriorly, knowledge of this vascular anatomy allows this muscle to be elevated proximally based on the thoracodorsal artery, or designed as distally based on the secondary vessels. The thoracodorsal fascia of the posterior trunk is a fusion of latissimus dorsi muscle aponeuroses and deeper fascial planes. This complex inserts on the posterior iliac crests and sacrum, it has a random blood supply. The design of a latissimus dorsi bipedicled flap to cover a defect distal to the iliac crest should include this fascia to enhance the blood supply through the fascial plexus. Patients and methods Figure 2 (A) A newborn male with a large meningomyelocele. (B) Elevation of the distally based Latissimus dorsi, skin island-muscle pedicle flap. (C) One-year postoperative, stable wound healing is demonstrated. defects in spina bifida. Combined LD and gluteus maximus myocutaneus flaps were described by Ramirez et al. 10 for reconstruction of large thoracolumbar and lumbosacral defect, Hayashi 11 described in a case report the use of bilateral V Y LD myocutaneus flap for closure of thoracolumbar MMC. Between 1997 and 2001, we used 39 LD myocutaneous flaps, in three different designs, to treat 23 thoracolumbar meningomyelocele defects. The age at operation ranged between 1 and 5 days (mean 2.7), one patient underwent surgery at the age of 17 days (parents initially refused surgery). Eighteen patients had hydrocephalus and paraplegia, and 11 patients had sphincter problems. Defect size was ranged from cm to cm. Nine patients underwent bilateral bipedicled LD myocutaneous flaps, seven patients underwent bilateral proximally based LD island myocutaneous flaps, and seven patients had unilateral distally based LD island myocutaneous flaps. All patients underwent immediate reconstruction following the repair of the neural tube and dura. Patients were operated upon in the prone position and under general endotracheal anesthesia. We used 4/0 vicryl for subcutaneous closure and 4/0 vicryl rapine for skin closure and suction drainage for 48 h. Postoperatively, patients were kept prone for 4 few days.

4 414 H.A. El-khatib Surgical techniques Proximally based LD skin island muscle pedicle flap This flap is indicated to cover large and high-lying defects, which is not distal to the iliac crest. The V Y design of LD myocutaneous flap was described by Hayashi 11 in one case report. Two triangular skin island flaps were designed on each side of the defect (Fig. 1), the tip of the triangle is extended to the posterior axillary line. Dissection is commenced on the thoracolumbar fascia, the latter is freed from the paraspinous muscles, and dissection continued under LD muscle to the tip of the skin island, the cranial border of the skin island is deepened to the muscle fascia, and under the muscle, continued to create a proximally-based muscle pedicle on the thoracodorsal artery. Dissection is complete when the skin island can advance towards the midline; bilateral flaps are usually designed to cover a large defect and sutured together in the midline in three layers. The donor site is closed as in V Y fashion (Fig. 3(C)). Distally-based LD skin island muscle pedicle flap Vanerkollk 12 and Sheflan 13 reported on the reverse LD muscle flap. This technique is indicated in moderate (8 5 cm) and low-lying defects (distal to the iliac crest). The author designed the skin island 1 cm. Larger than the original defect, outlined in an oblique direction, and not overlying the anterolateral portion of the LD muscle (Fig. 1). Another skin incision is extended from the tip of the skin ellipse to the margin of the defect (Fig. 2(B)). The skin incision is deepened to the muscle fascia, and then dissection proceeds along the surface of the muscle in all directions away from the skin island, and along the incision towards the defect. An incision is then deepened under the muscle in order to obtain a sleeve surrounding the overlying skin island, and to develop a muscle pedicle. This pedicle should incorporate two segmental posterior intercostal perforators. A fine probe Doppler is used to delineate the location of these perforators, the flap is elevated and tailored to the defect and the donor site is closed primarily. Figure 3 (A) The thoracolumbar meningomyelocele in 2-day-old female infant. (B) The defect following the dural and neural tube repair. (C) Elevation of proximally based latissimus dorsi, skin island-muscle pedicle flap. (D) Result two months after surgery.

5 Large thoracolumbar meningomyelocele defects 415 Table 1 Summary of patients data Patient no. Sex Age at operation days Size of defects cm Procedures Neurologic deficits Sphincters problems Complication 1 M Proximally-based LD Hydrocephalus and paraplegia þve Marginal necrosis 3 F Distally-based LD Same 2ve 5 F Distally-based LD Isolated 2ve 7 M Bil. biped LD Paraplegia þve 9 F Distally-based LD Isolated 2ve 11 M Same Paraplegia þve 13 M Proximally-based LD Paraplegic, hydrocephalus þve Marginal necrosis 17 M Same Hydrocephalus, paraplegia þve Wound deh. (2 cm) 23 M Same Same þve Patients profile (cont.). Bil., bilateral; Biped., bipedicled; LD., latissimus dorsi. Bilateral bipedicled LD myocutaneous flap The flap is a good tool to cover huge thoracolumbar defects, provided that the thoracolumbar and gluteal fascia are incorporated into the flap to increase its blood supply. McCraw, 7 Moore 8 and Ramirez 10 described the original bilateral bipedicled LD myocutaneous flap. In our technique, elevation of the flap starts from the margin of the defect, where the LD muscle is defined, and a proper plane on the undersurface of the muscle is easily found. Dissection proceeds laterally towards the anterolateral border (Fig. 1) where the muscle is freed from the underlying external oblique and serratus posterior muscles if necessary. We try to preserve the muscular perforators and divide both posterior intercostal and lumbar perforators in order to obtain a good advancement. Dissection continues inferiorly deep to the thoracolumbar fascia and in continuity with gluteus maximus fascia. A relieving incision along the posterior axillary fold is performed; this incision is deepened only over the muscle fascia to add more medial advancement. The secondary defect is closed by a split-thickness skin graft. The procedure is repeated on the opposite side, both flaps are approximated in the midline with no tension and closed in three layers. Results The study was conducted between 1997 and 2003, and included 23 babies with thoracolumbar MMC. Defects were closed by the author at Hamad General Hospital in state of Qatar. The study included only 23 patients who met the inclusion criteria. The office of Birth Notification and the department of Neonate intensive care unit at Hamad Maternity Hospital provided the number of live births and the number of MMC cases. This is the only hospital, and takes care of all deliveries in the country. All patients were seen, and their medical charts reviewed by the author during the follow-up. The average operative time in bipedicled LD flap was around 90 min, in bilateral proximally based LD flap was around 100 min, and in distally based LD flap was around 75 min. Amount of blood loss was ranged between 15 and 25 cc. Two proximally based LD flap developed marginal flap necrosis, and were treated conservatively. Another two bipedicled LD flaps developed partial wound dehiscence (2 cm long) and were left to heal by secondary intention (Table 1). All patients tolerated the procedures smoothly, and no long-term complications including wound breakdown, shoulder function have been reported (Figs. 2(C), 3(D) and 4(B)). Table 2 Total incidence per 1000 by years Year Live birth Total Meningocele Total incidence per 1000 Female Male Female Male Total Total

6 416 H.A. El-khatib Discussion Figure 4 (A) Three-day-old male infant sustained a huge thoracolumbar meningomyelocele. (B) Two years after bilateral bipedicle latissimus dorsi myocutaneous flap reconstruction. Very stable wound healing is shown. MMC results from abnormal fusion of the posterior neural tube and produces obvious changes in the distal spinal cord and cauda equina. Eighty or ninety percent of patients have or will develop hydrocephalus. The long-term outcome in surgically treated spina bifida defects was reported by Hunt and Poulton 15 in They studied 117 cases, of which 56 had died, and 61 survived, 33 were living independently, and 28 required supervision and help. In another report by Date et al. 16 the outcome of 72 patients was reviewed, at follow-up of 4 20 years. Seventeen had died, and all cases involving only meningocele were living without handicap. Patients with hydrocephalus had a higher morbidity and mortality. The reported incidence of MMC varies from 1 per 1000 live births 1 to 0.8 per 1000 live births. 2 This study reports the incidence in the gulf region (QATAR) as 0.6 per 1000 live births (Table 2). Coverage of MMC defect should be tension free, prevent cerebrospinal fluid leak, and provide a good soft tissue padding for the neural tube, the techniques described in this report provide three layers closure in order to prevent scar breakdown. In addition, the report describes a few modifications to preserve the LD muscle function because of its future importance for mobility, and to simplify the flap harvesting in order to decrease the blood loss and time of surgery. Various methods have been suggested for repair of MMC defects. 7,8,10,17 Our technique for combining LD and gluteus maximus units leaves the lateral border of the muscle undisturbed to preserve the muscle function. We did not find difficulties using this technique, in closing larger defects, and the closure is tension free. Shaflan 13 reported the distally based LD flap. In our technique, the flap is elevated as a skin-muscle island pedicled on a sleeve of muscle, which incorporates at least two segmental perforators, the flap is designed in an oblique direction to obtain a wider arch of rotation. The donor site is closed primarily and without a dog-ear. And finally the edges of the cut muscle are tacked to the chest wall in order to preserve its function. We recommend this technique in low-lying and moderate-size (8 5 cm) thoracolumbar defects. Hayashi 11 described in one case report the bilateral V Y musculocutaneus flap, the lateral tip of the triangle extend laterally beyond the midaxillary line, and the lateral border of the muscle is sharply dissected from its attachment to the serratus posterior and external oblique muscles. In

7 Large thoracolumbar meningomyelocele defects 417 our technique, skin-muscle island is based proximally in a muscle pedicle and supplied by the thoracodorsal artery, in which the anterolateral border as well as the lower half of the muscle is not dissected, and again the cut edges of the muscle is tacked to the chest wall, to preserve the muscle function. We prefer to do this technique in defects located proximal to the iliac crest, in order to avoid distal necrosis of the flap secondary to relative poor blood supply of the thoracolumbar fascia. In a follow-up ranging from 2 to 7 years, and there was no patient showed signs of weakness of the function. Patients with hydrocephalus had higher morbidity and mortality of the upper extremity; however, a long-term follow-up should be available. Knowledge of the vascular territories of the latissimus dorsi muscle enable the surgeon to select the best technique for each defect. An operative procedure for MMC ought to be planned with the goals of simplicity, minimal blood loss, preservation of function and avoidance of alteration in soft tissue anatomy, in order to provide additional tension free padding, with no cerebrospinal fluid leak and no sepsis. We prefer the use of myocutaneous flaps for adequate padding over the neural tube, and to provide more blood supply to the region. Avoidance of dissection of the anterolateral border of the latissimus dorsi muscle from the external oblique and serratus posterior muscles, in addition to fixing the cut edges of the muscle to the chest wall, and harvesting approximately half of the muscle will help to preserve some of the muscle function. Acknowledgements The author wish to thank Dr Attala Hammouda for his help in collecting the data. References 1. Greenberg F, James LM, Oakley Jr GP. Estimates of birth prevalence rates of spina bifida in the United States from computer-generated maps. Am J Obstet Gynecol 1983;145: Lapid O, Rosenberg L, Cohen A. Meningomyelocele reconstruction with bilobed flaps. Br J Plast Surg 2001;54: Gil Z, Aran A, Friedman O, Beni-Adani L, Constantini S. Folic acid use by pregnant women in Israel for preventing neural tube defects. Harefuah 2000;139: Hunt GM, Oakeshott P. Outcome in people with open spina bifida at age 35: prospective community based cohort study. BMJ 2003;326: Luce EA, Walsh J. Wound closure of the myelomeningocoele defect. Plast Reconstr Surg 1985;75: Mustarde JC. Reconstruction of the spinal canal in severe spina bifida. Plast Reconstr Surg 1968;42: McCraw JB, Penix JO, Baker JW. Repair of major defects of the chest wall and spine with the latissimus dorsi myocutaneous flap. Plast Reconstr Surg 1978;62: Moore TS, Dreyer TM, Bevin AG. Closure of large spina bifida cystica defects with bilateral bipedicled musculocutaneous flaps. Plast Reconstr Surg 1984;73: Blaiklock CR, Demetriou EL, Rayner CR. The use of a latissimus dorsi myocutaneous flap in the repair of spinal defects in spina bifida. Br J Plast Surg 1981;34: Ramirez OM, Ramasastry SS, Granick MS, Pang D, Futrell JW. A new surgical approach to closure of large lumbosacral meningomyelocele defects. Plast Reconstr Surg 1987;80: Hayashi A, Maruyama Y. Bilateral latissimus dorsi V Y musculocutaneous flap for closure of a large meningomyelocele. Plast Reconstr Surg 1991;88: Vanderkolk CA, Adson MH, Stevenson TR. The reverse latissimus dorsi muscle flap for closure of meningomyelocele. Plast Reconstr Surg 1988;81: Scheflan M, Mehrhof Jr AI, Ward JD. Meningomyelocele closure with distally based latissimus dorsi flap. Plast Reconstr Surg 1984;73: Stevenson TR, Rohrich RJ, Pollock RA, Dingman RO, Bostwick III J. More experience with the reverse latissimus dorsi musculocutaneous flap: precise location of blood supply. Plast Reconstr Surg 1984;74: Hunt GM, Poulton A. Open spina bifida: a complete cohort reviewed 25 years after closure. Dev Med Child Neurol 1995; 37: Date I, Yagyu Y, Asari S, Ohmoto T. Long-term outcome in surgically treated spina bifida cystica. Surg Neurol 1993;40: Zide BM. Spina bifida. In: McCarthy JG, editor. Plastic surgery. Philadelphia: W.B. Saunders Co; p