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NOTES AND NEW TECHNIQUES

A SENSORY INNERVATED LATlSSlMUS DORSI MUSCULOCUTANEOUS FREE FLAP: CASE REPORT

Richard W. Dabb, MD, and William T. Conklin, MD

Abstract: The latissimus dorsi musculocutaneous free flap has been shown to be a useful tool in recon- structive surgery. Sensory innervation of the vas- cular territory of the latissimus dorsi is presented. This anatomic principle is applied in a free transfer of a latissirnus dorsi musculocutaneous flap for reconstruction of the volar area of a foot following a severe frostbite injury.

JOURNAL OF MICROSURGERY 2:28*293 1981

One of the most useful tools now available for the reconstruction of major soft tissue defects of the lower extremity is the musculocutaneous free flap. Free flaps have several advantages: they are single-stage procedures; they can be used in the face of concomitant fractures with external appliances: and they allow shorter hos- pitalization and earlier ambulation.

Of the many musculocutaneous flaps avail- able, the latissimus dorsi flap appears to be the most versatile. The use of the latissimus dorsi as

From York Plastic Surgery Associates, Ltd. (Dr. Dabb) and York Hospital (Dr. Conklin), York, PA.

Address reprint requests to Dr. Dabb at York Plastic Surgery Associates, 5 Rathon Rd., York. PA 17403.

Received for publication February 19, 1981; revision received July 1, 1981.

01 91 -3239/0204/0289 $01.25/0 (D 1981 John Wiley & Sons, Inc.

a rotational flap in the breast, head, neck, chest, and upper extremity has been well established. In 1978, Maxwell et al., performed the first suc- cessful free transfer of a latissimus dorsi mus- culocutaneous flap to repair a large scalp defect.' In 1979, Maxwell et al. reported on further cases, thus documenting its versatility.2

There are several characteristics that make this flap most desirable. The latissimus dorsi muscle is large, and a large skin paddle can be fashioned. The muscle is expendable, and the donor area usually can be closed primarily. The latissimus dorsi flap has been documented to have a greater blood flow per gram of tissue than other flaps, and it tolerates longer periods of is- chemia than the commonly used groin flap.3 It has a single, large, long, consistently placed neurovascular pedicle, which allows for less flap isolation time and anastomosis to vessels beyond the area of t r a ~ m a . ~ The T-shaped vascular pedi- cle, composed of the junction of the subscapular artery and vein and the circumflex scapular ar- tery and vein, forming the thoracodorsal pedicle, may be used for easy end-to-end anastomosis and the bridging of vascular defects. Tobin and Schusterman demonstrated the consistent proximal bifurcation of the thoracodorsal neurovascular pedicle and the potential for mus- cle splitting in the latissimus dorsi flap, fur- thering its ver~ati l i ty.~ Motor innervation can be obtained by anastomosis of the thoracodorsal nerve to a suitable nerve in the recipient site.

Latissimus Dorsi Musculocutaneous Flap JOURNAL OF MICROSURGERY June 1981 289

CUTANEOUS BRANCHES OF DORSAL RAM1

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I

I

BRANCH OF INTERCOSTAL NERVE I

I

Figure 1 . The anatomy of the sensory cutaneous branches of the dorsal rarni of the spinal nerves.

The remaining clinical problem in the utili- zation of this versatile flap is sensory innerva- tion. This article describes the anatomy of the sensory innervation of the latissimus dorsi re- gion and presents a case in which sensory inner- vation of a latissimus dorsi free flap was applied in the coverage of a defect of the foot.

ANATOMIC DESCRIPTION

The skin of the vascular territory of the latis- simus dorsi muscle is sensory innervated by 2 systems of nerves: the cutaneous branches of the dorsal rami and the posterior branches of the lateral cutaneous branch of the intercostal nerve (Figs. 1 and 2)P Both of these systems arise from the spinal nerves. Anteriorly, the posterior

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POSTERIOR BRANCHES LATERAL CUTANEOUS

NERVE FROM INTERCOSTAL

Figure 2. The anatomy of the sensory posterior cutaneous branches of the lateral cutaneous nerve.

branches of the lateral cutaneous branch of the intercostal nerve are found to arise through the fenestrations of the serratus anterior muscle. They appear to interdigitate with the long thoracic nerve, which is a helpful landmark in locating them. The posterior branches then traverse the lateral margin of the latissimus dorsi muscle and enter the vascular territory in the subcutaneous plane. The more dorsal portion of the vascular territory of the latissimus dorsi receives cutaneous branches from the dorsal rami. These branches directly perforate with the posterior perforating arteries and veins. These multifascicular nerves are seen in the submus- cular plane accompanying the artery and vein. Both systems may be dissected into the intercos-

Figure 3. A preoperative photograph of the volar area of the right foot.

290 Latissimus Dorsi Musculocutaneous Flap JOURNAL OF MICROSURGERY June 1981

Figure 4. A preoperative photograph of the dorsal area of the right foot. tissues.

Figure 5. The right foot after debridement of the gangrenous

tal spaces; thus nerve segments 4 to 8 cm in length may be obtained.

CASEREPORT

A 32-year-old male was transferred to our service 1 month following fourth-degree frostbite injury to both legs. He was treated initially with long- acting epidural blockade and conservative treatment. One week before transfer he under- went amputation of the left leg below the knee. Upon examination, his right foot showed dry gangrene extending from the level of the dorsal metacarpal head to the volar heel pad (Figs. 3 and 4). Posterior tibial and anterior tibial ar- teries were palpable. There were spotty areas of sensation over the heel and the dorsum of the

Figure 6. An intraoperative photograph showing the dissection of the sensory nerves to the flap.

foot. A bone scan revealed activity of the cal- caneus and tarsals. An arteriogram revealed gross patency with small vessel damage, throm- bosis of all digital vessels, and linear damage of the distal posterior tibial artery.

At surgery, all gangrenous areas were de- brided, including all interosseous muscles, the volar skin, and a small amount of the dorsal skin. The distal metatarsals were resected; bleeding from the periosteum was noted (Fig. 5). The pat- tern of the skin deficiency was transferred to the latissimus territory of the latissimus dorsi and a flap was elevated. At the time of flap elevation, the lateral incision was made first, just through skin, followed by blunt hemostatic separation down to the serratus muscle and long thoracic

Latissimus Dorsi Musculocutaneous Flap JOURNAL OF MICROSURGERY June 1981 291

nerve. At that point, the posterior branches of the lateral cutaneous nerves were easily identified and, under magnification, dissected out back to the skin paddle. The thoracodorsal pedicle was dissected and a T-shaped pedicle obtained by dissection of the subscapular and circumflex scapular systems. The latissimus submuscular plane was entered and bluntly separated from the chest wall. The posterior perforators with their accompanying cutane- ous branches of the dorsal rami were easily identified (Fig. 6). Both nerve systems were dis- sected into the respective intercostals, clipped, and transected. Flap isolation was completed

Figure 7. An intraoperative photograph showing the anastomosis of the branch of the cutaneous nerve to the medial plantar nerve at the ankle.

and flap viability reconfirmed with fluorescein. The flap was transferred to the foot where

prior dissection had isolated the posterior tibial artery and veins, the posterior tibial nerve and its medial plantar branch, and the anterior tibial nerve. The flap was vascularized by interposing the T-pedicle into the posterior tibial artery and, with a single vein graft, to a more proximal por- tion of the posterior tibial vein. A second simple venous anastomosis was done. After flap via- bility was confirmed, 2 posterior cutaneous branches of the lateral cutaneous branch of the intercostal nerve were anastornosed to the me- dial plantar branch of the posterior tibial nerve

Figure 8. The anastomosis of the anterior tibial nerve and the cutaneous branch of the dorsal rami.

292 Latissimus Dorsi Musculocutaneous Flap JOURNAL OF MICROSURGERY June 1981

111 VEIN GRAFT

THORACODORSA L ARTERY AND VEIN

CUTANEOUS BRA

LATERAL CUTANEOUS BRANCHES OF INTERCOSTAL NERVE

Figure 9. A diagram of the flap showing its orientation and the sites of anastomosis of the arteries, veins, and nerves.

with interfascicular sutures of 10-0 nylon (Fig. 7). Three cutaneous branches of the dorsal rami then were anastomosed to the anterior tib- ial nerve with interfascicular sutures of 10-0 nylon (Figs. 8 and 9). The flap was inset, and the redundant muscle skin was grafted (Fig. 10).

RESULTS

There were no immediate postoperative compli- cations. A t 6 months, the patient reported sensa- tion in the central portion of the flap to pinprick and pressure (Fig. 11). Ambulation has been limited by the patient’s motivation.

DISCUSSION

The pathophysiology of severe frostbite injury with its associated vascular occlusion and capillary and arteriolar thrombosis leading to ischemic neuritis of residual tissue is well known. The natural course is one of long-term disability.’

In this case of severe fourth-degree frostbite injury with well-demarcated gangrene of the toes and volar area of the foot, a latissimus dorsi musculocutaneous free flap was used to cover the defect because of the well-known advantages and excellent vascularity of the flap. In addition, a new technique, that of innervating the flap for sensation, was applied. The cutaneous branches of the spinal nerves of the vascular territory of the latissimus dorsi were found to be of reason- able length and number and relatively easy to dissect and prepare for anastomosis. The addi- tional step did not add significantly to the length of the operation. Six months postoperatively the patient reports sensation in the central portion of the flap.

Figure 10. The latissimus dorsi flap immediately after completion of the surgery.

Figure 1 1 . Photograph of the flap taken 6 months after surgery. The patient reports sensation to pinprick and pressure in the stippled area.

REFERENCES

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6.

7.

Maxwell GP. Stueber K, Hoopes JE: A free latissimus dorsi myocutaneous flap. Plast Reconstr Surg 62:462-466, 1978 Maxwell GP, Manson PN, Hoopes JE: Experience with thirteen latissimus dorsi myocutaneous free flaps. Plast Reconstr Surg 64:l-8, 1979 Lynch JB: Plastic surgery and burns. Bull Am Coll Surg

Bostwick J 111, Scheflan M, Nahai F, Jurkiewicz MJ: The “reverse” latissimus dorsi muscle and musculocutaneous flap: anatomical and clinical considerations. Plast Recon- sir Surg 65:395-399, 1980 Tobin GR, Schusterman BA: The anatomical basis for splitting the latissimus dorsi myocutaneous flap. Pre- sented at the 25th annual meeting of the Plastic Surgery Research Council, Hershey, PA, April, 1980 Sobotta J: Atlas of Descriptive Human Anatomy. Vol. 1 . New York. Hafner, 1957, pp 46-47 Schwartz SI, et al: Principles of Surgery. 3rd ed., Vol. 1 . New York, McGraw-Hill, 1979, pp 975-976

66:48-51, 1981

Latissimus Dorsi Musculocutaneous Flap JOURNAL OF MICROSURGERY June 1981 293