Microsurgical reconstruction of major scalp defects following scalp avulsion.

INTRODUCTION: Total scalp avulsion is a serious injury, commonly occurring in Indian females working with industrial and agricultural machines. Their long hairs often get caught in a rapidly revolving machines, resulting in total avulsion of scalp. Lack of education and awareness in Indian villages often result in these patients coming late to the hospitals when replantation is not possible and scalp reconstruction remains the only available option.
MATERIALS AND METHODS: We performed our study on 22 cases of scalp avulsion injury presented to us between June 2007 and April 2012 at Department of Burn, Plastic & Reconstructive Surgery, SMS Hospital, Jaipur. In all of them a free tissue transfer was performed as an elective procedure.
RESULTS: Twenty two patients underwent free tissue transfer and followed up for an average period of 6 months. All patients included in this study were females with mean age of 28 yrs. Five patients in our study reported with partial necrosis of the free flaps which were subsequently managed with split-thickness skin graft (STSG). Two patients reported total necrosis of the flap which was re-operated using latissimus dorsi along with serratus anterior muscle (LDSA) from the contralateral side.
CONCLUSION: As scalp avulsion because of rapidly rotating machine leads to large size defect not amenable for local tissue reconstruction. We performed reconstruction using LDSA and omental free flaps with split thickness skin graft (STSG) for large scalp defect and achieved good and stable soft tissue cover with satisfactory cosmesis.

INTRODUCTION

Scalp avulsion is a common accident occuring particularly in Indian females working in villages, because their hair get caught in a rapidly rotating thresher machine [Figure 1] used in farming. Scalp usually separates where the scalp skin is thin and the cleavage line most commonly located in loose areolar and relatively less vascular tissue. The periosteum is frequently found to be intact and rarely patient present with skull bone fracture. Patients might present with partial or total loss of one or both ears along with the scalp.[1]

Figure 1

Thresher machine

Reconstruction of large scalp defects present with some challenging problems. Patients with scalp avulsion injury leave distinctly a large area demanding large flap for cover. Recipient vessels frequently found to be stretched and damaged because of avulsion injury; consequently a flap with long pedicle is needed if we are to avoid the use of vein graft. Since it is difficult to prevent localized flap necrosis as head comes in contact with bed, positioning the patient especially in post operative period poses another challenge.

MATERIALS AND METHODS

Twenty-two free tissue transfers for large scalp defects were done between June 2007 and April 2012, at SMS Hospital, Jaipur. Medical records of 22 consecutive patients presented with scalp avulsion injury were examined. Details were collected on the patient's age, sex, socioeconomic status, mode of injury, timing of presentation, defect size and location, presence or absence of periosteum and patient co-morbidities. The defect was staged according to the system described in Table 1.[2] All the patients included in this study were females and belong to low socioeconomic status along with poor education level. All the patients were followed up for an average period of 6 months (1month to 1 year).

Table 1

Staging system for forehead and scalp defects[2]

All the patients were assessed for co-morbidities and associated trauma at the time of admission. Other injuries along with scalp avulsion were found in seven patients. Two patients present with fracture both bone forearm and one with closed fracture of both bones of one leg. One patient exhibited moderate pleural effusion which was managed by intercostal drainage for 5 days. One patient present with 7 month amenorrhea, this was optimized by obstetrician, and then patient taken up for surgery. In all the patients neurosurgical, cardiothoracic and orthopaedic evaluations were done, and after proper optimization in terms of haemogram, neurological status, pulmonary status and stabilization of fractures, patients were taken up for surgery. All patients were nursed in semi sitting position for 3 days in the post operative period. To avoid contact with bed and subsequent pressure necrosis of the flap, we used cervical pillow and soft bulky dressing. Nonetheless we observed partial necrosis in five patients.

Average timing of presentation was 8.7 days from the day of injury. Average length and width of the defect was 32.37 and 23.37 cm respectively, while average area was 767.5 cm2. Among the studied sample, two patients grouped in stage II as per staging system and rest of the patients grouped as stage III.

CASE REPORTS

Case 1 (Patient no 3)

A 27 year old female presented with total scalp avulsion (stage III defect) and intact periosteum. We did skin grafting immediately. Early post operative results were good with 100% graft take [Figure 2].

Figure 2

CASE 1: (a) Pre-op frontal view (b) pre-op postero-lateral view (c) third post-op day after STSG

Case 2 (Patient no 5)

A 30 year old lady presented late (after 30 days) with bare skull after scalp avulsion injury. Dead and necrotic calvarium was removed and reconstruction was done using omental free flap with STSG. There were no major complications in the post operative period apart from post operative ileus and partial necrosis of the flap [Figure 3].

Figure 3

CASE 2: Omental flap (a) post-op posterior view (b) post-op lateral view

Case 3 (Patient no 21)

A 32 year old lady presented with total scalp loss with bare skull bone. The patient also had fractured right forearm bones and mild pleural effusion right side. After management of associated trauma, patient was taken for scalp reconstruction. After removal of necrotic calvaria, LDSA flap with skin paddle based on a cutaneous branch arising from thoracodorsal-subscapular trunk composite free flap was done. As arterial flow was found to be low in superficial temporal vessels, pedicle was anastomosed to facial vessels using vein graft, tunneled at preauricular region. Flap healed well in the postoperative period with stable cover [Figure 4].

Figure 4

CASE 3: (a & b) Pre-op vertex view (c) pre-op posterior view (d) latissimus dorsi with serratus anterior with cutaneous paddle harvested on a single paddle (e) post op vertex view (f) 14th post-op day

Case 4 (Patient no 14)

A 35 year old lady presented to us with scalp avulsion injury from thresher machine. Scalp was reconstructed with latissimus dorsi muscle with STSG, but flap necrosed because of venous thrombosis. The patient again planned for surgery and LDSA with skin paddle, a composite free flap was done. This time vein was anastomosed with external jugular vein using vein graft tunneled at the preauricular region. There were no postoperative complication and flap recovery was uneventful [Figure 5].

Figure 5

CASE 4: (a) Pre-op vertex view (b) latissimus dorsi with serratus anterior with cutaneous paddle harvested on a single paddle (c) post op vertex view (d) post-op

Case 5 (Patient no 22)

A 40 year old lady presented with scalp avulsion injury from a thresher machine. Scalp reconstruction was done using LDSA flap along with skin paddle. There were no postoperative complications [Figure 6].

Figure 6

CASE 5: (a) Pre-op vertex view (b) latissimus dorsi with serratus anterior with cutaneous paddle harvested on a single paddle (c) post-op (d) 14th post-op day

RESULTS

A total 22 patients with scalp avulsion injury presented to our service during last 5 years. We did skin grafting in 2 patients, omental free flap with STSG in 2 patients, free latissimus dorsi muscle flap with STSG in 5 patients, free LDSA muscle flap with STSG in 15 patients.

Both the skin grafted patients develop unstable scars and raw areas in the follow up period. One patient treated with omental flap developed partial necrosis while another patient showed no major complication in the post-operative period. Both the patients developed post operative ileus. We treated five patients with free latissimus dorsi muscle flap with STSG, out of which total necrosis was reported in two cases and partial necrosis in one patient. Patients with total necrosis of the flap managed successfully due to re-operating and reconstruction using LDSA flaps. One patient with partial necrosis was managed with skin grafting.

Fifteen patients in this study were reconstructed using free LDSA muscle flap with STSG. Three patients among this group reported partial necrosis of the flap which was managed successfully with skin grafting. Three patients reported minimal donor site seroma formation. Remaining 12 patients showed no major complications and flap healed well without any complication [Table 2].

Table 2

Clinical details of the patients

DISCUSSION

Scalp is a soft tissue envelope of the cranial vault. It extends from external occipital protuberance and superior nuchal lines to the supraorbital margins. Scalp is having five layers which include skin, connective tissue epicranial aponeurosis, loose areolar tissue and pericranium. The first three layers bound together as a single unit and this can move along the loose areolar tissue over the pericranium which is adherent to the calvaria. In scalp avulsion injury, scalp usually separate at the level of loose areolar tissue, which is relatively avascular.

The proper choice of a reconstructive technique is affected by several factors — the size and location of the defect, the presence or absence of periosteum, the quality of surrounding scalp tissue, the presence or absence of hair, location of the hairline and patient co-morbidities. Successful reconstruction of these defects requires a detailed knowledge of scalp anatomy, hair physiology, skin biomechanics and the variety of possible local tissue rearrangements. In nearly total defects, local tissues may be inadequate and free tissue transfer may be the only alternative.[3]

Total scalp avulsion is uncommon injury occurring due to agricultural and industrial accidents. Scalp avulsion injury usually associated with significant comorbidities. Reconstruction of complex defects due to scalp avulsion still remains challenging problem for the reconstructive surgeon. As in all areas of reconstructive surgery, the best tissue coverage is the original tissue if possible. In 1976, Miller published the first successful microsurgical replantation of avulsed scalp.[4] Many other cases and series have since been reported. Microvascular replantations achieve by far the best aesthetic and functional results compared with other procedures.[456789101112]

Various other methods to provide coverage of scalp defects have been published in the literature so far.

Replantation of avulsed scalp as a composite graft had rarely been successful unless microvascular anastmosis was performed.[1314]

Simon et al. reported use of artificial dermis followed by thin skin graft in 15 yr old girl with total, non replantable scalp avulsion. Total healing was achieved after 7 weeks and no ulceration occur at 2 year follow up.[15]

Kriengsak Sirirak reported that the morbidity is great after removal of the outer table of the skull to provide a vascular bed for skin grafting when periosteum is missing. The scar is unsightly and the wound is often unstable; even when the pericranium is intact, skin grating of wound yields an adherent hairless skin.[16]

Furlanetti et al. reported exposure of the diploe along with skin grafting, with multiple burr holes as a safe and effective method for treating scalp avulsion injury when microsurgical replantation fails or not feasible.[17]

The superficial temporal artery has been the most successfully used recipient vessels for free tissue transfer in this study. Accompanying veins provide venous drainage. However placement of interposition vein grafts was required in two cases. In these two cases, superficial temporal artery found to be injured with decreased blood flow. After avulsion injury of the vessels endothelial disruption occurs with exposure of elastic lamina which ultimately leads to stasis and thrombosis. This mechanism relates with increasing avulsion forces and usually found in acute cases. In our study maximum cases present late and we found adequate flow of superficial temporal vessels in these patients. In first case we anastomose donor vessels with facial artery and external jugular vein using vein graft and in another case only venous anastomosis to external jugular vein was done using vein graft which was tunneled at the preauricular region. In the first case we reported partial flap necrosis and in latter only partial graft loss was observed.

In certain condition when avulsed scalp is unavailable or replantation is impossible, scalp reconstruction must be done to minimise morbidity.[16] Well revascularised free tissue transfer like free omentum transfer, anterolateral thigh flap, latissimus dorsi free flap, latissimus dorsi with serratus anterior free flaps or free parascapular flap may be a choice to make good soft tissue coverage of denuded skull.[18]

The first clinical use of omental free tissue transfer for scalp defect was reported by McLean and Buncke in 1972. They do microvascular transplantation of the omentum to a large skull defect and cover it with skin graft.[19]

The average omental length is 24 to 25 cm, with an average width of 33 to 35 cm. The omentum is one of the largest autologous composite tissues available for transplantation (i.e. 792-875 cm2). As a result of its excellent microcirculation and phagocytic activity, the omentum is particularly suited to reconstruction of an unsuitable and compromised recipient site.[2021] Positive attributes of the omental flap include its vascularity, long pedicle length and malleability, which allow the tissue to fold and conform to a three dimensional wound. Another advantage of omental flap is that there is no need to change position of the patient. The necessity of laparotomy and post operative ileus is the obvious disadvantage, and previous abdominal surgery may preclude use of omentum.[16]

The latissimus dorsi muscle is a large, flat, triangular muscle covering posterior inferior half of the trunk. Latissimus dorsi is a type V muscle whose dominant pedicle is thoracodorsal artery which is a branch of subscapular artery which enters deep surface of the muscle in the posterior axilla 10 cm inferior to the muscle insertion into the humerus. The average size of the muscle is 25 × 35 cm (875 cm2).[22]

Serratus anterior muscle is a thin, broad, multidigitated muscle on the lateral chest wall between ribs and scapula. Serratus anterior muscle is a Type III muscle having dual blood supply. The inferior three slips of serratus anterior muscle (arising from sixth, seventh and eighth ribs) can be used without significantly impairing shoulder function. The area covered with inferior three to four slips covers area approximately 12 × 18 cm (216cm2).[2324]

As mentioned in previous studies free tissue transfer such as latissimus dorsi muscle or musculocutaneous flap may be optimum choice to make good tissue coverage of denuded skull because muscle itself is large enough to cover entire scalp.[16] But it has been observed in our study that latissimus dorsi muscle flap alone as a cover for total scalp avulsion found to be somewhat shorter than required. We found complete and better coverage in our patients in whom we did LDSA muscle flaps, than in patients with only latissimus dorsi muscle flaps.

In our study we used omentum free flaps, latissimus dorsi free flaps, LDSA flaps and LDSA flaps including skin paddle based on unnamed branch of thoracodorsal artery. We took lower 4 slips of serratus anterior along with latissimus dorsi muscle in our patients. We found no limitation of shoulder movement in any case of our study, though it was restricted initially but improved over a period with physiotherapy.

Harii et al. in his study reported no marked limitations of shoulder adduction and backward extension while using both latissimus dorsi and serratus anterior muscle as a free tissue transfer.[25]

Normal anatomy and variations of the axillary artery and thoracodorsal artery have been well described in the literature. In our two cases we found a direct cutaneous branch arising from thoracodorsal-subscapular trunk to supply anterolateral skin of the chest wall. We took a separate skin paddle based on this vessel [Figure 4 & 5]. However Rowsell et al. and Cabanie et al. have been reported presence of direct cutaneous branch arising from subscapular-thoracodorsal arterial system in 81% and 55% of cadaveric dissections respectively in their studies.[2627] Further anatomical and cadaveric studies are needed to evaluate any constant origin of this branch as a skin paddle can be taken based on this branch for forehead reconstruction.

Scalp avulsion injuries commonly occur in female farm workers of any age having their long hairs entangled in rotating machinery of any type. Most commonly, these injuries happened during summer and rotatory harvesting machine were found responsible for avulsion injuries. Educational status of these patients was low and necessary precautions to avoid such injuries were not taken. Prevention, of course, is the best management of this trauma, any men or women with long hair, who work with rotating machine, are in great hazard.[16] These injuries were entirely preventable had helmets and machinery cover been in place. As reconstruction of total scalp loss with LDSA gives bald look; a wig may be used as a less intrusive and less expensive alternative to therapies for restoring hair.

CONCLUSION

Free tissue transfer is a reliable and safe way of reconstructing total scalp defects after scalp avulsion injury. The muscle only latissimus dorsi flap along with serratus anterior with STSG for large defect scalp reconstruction proved successful in selected patients with a stable soft tissue cover, low complication rate and satisfactory cosmesis.