Protocols and complications in the reconstruction of major scalp defects

1 Universidade Positivo, Curitiba, PR, Brazil. 2 Faculdade Evangélica Mackenzie do Paraná, Curitiba, PR, Brazil. Conflicts of interest: none. Introduction: This study aimed to analyze the protocols and complications in four unusual cases of large and complex scalp defects, in which conventional, non-microsurgical flaps were used. Methods: This was a critical and retrospective analysis of four cases. Three immunosuppressed patients had squamous cell carcinomas (SCC) (one underwent liver transplant, one underwent renal transplant, and one had rheumatoid arthritis). The other patient had sequelae of head trauma and multiple neurosurgeries using self-polymerizing acrylic, followed by osteomyelitis and fistula. Results: The cases of large carcinoma were reconstructed with rotation large scalp flaps. Two of them had epidermolysis/necrosis in a small distal portion of the flaps, which were treated, with excellent aesthetic results. The case of sequelae of trauma was reconstructed with expanded advancement scalp flap over cranioplasty using ribs. Despite the extrusion of one osteosynthesis, the patient healed without recurrence of the fistula, with an excellent aesthetic result. Conclusion: The analysis of these complex and unusual cases indicates that temporal pedicles are preferred in the planning of flaps for the conventional reconstruction of large scalp defects. The treatment employed for the possible epidermolyses and distal necroses in these flaps led to satisfying aesthetic and functional results. ■ ABSTRACT


INTRODUCTION
The outer table of the calvarium receives nutrition through the periosteum. Large scalp defects owing to trauma or neoplasms can endanger the vitality of the bones of the neurocranium, dura mater, and underlying brain. The loose connective tissue between aponeurotic galea/epicranium muscle and periosteum favors intracranial metastases, thrombi, and infections 1 .
Large scalp defects are a major challenge for reconstruction, and in the absence of periosteum, these impair the use of skin grafts. Decortication of the outer table for skin grafting of the diploe provides aesthetically poor results, leading to fragility and susceptibility to malignancy. Romero et al., in 2018 2 , published an algorithm recommending microsurgery for defects larger than 5 cm. Although vascular microsurgery provides the best results in the repair of large scalp defects 3 , it requires adequate team and resources. Souza, in 2012 4 , used local flaps and emphasized the importance of superficial temporal vessels in maintaining the viability of these flaps.

CASE 4
An adult male patient who was struck with an ax seven years ago suffered head trauma. He was operated four times at Neurosurgery Services. For more than once, cranioplasty was performed with selfpolymerizing acrylic, followed by subsequent infection and frontoparietal osteomyelitis, requiring the removal of the implant and new bone debridement (Figure 4).   At another service, he received partial skin graft placed directly on the remaining dura mater and the presumably performed galeal flap. Initial examinations revealed a frontoparietal defect, subdural clamps, and a clinically significant fistula draining serous material over the brain mass precariously protected by the graft. He had convulsive episodes after suffering minor trauma in the graft region during his work as a car mechanic.

DISCUSSION
The low elasticity, thickness of the skin and subcutaneous tissue, and presence of a thick aponeurotic galea on a convex surface make the reconstruction of large scalp defects a challenging task. Abundant anastomoses between the temporal, supraorbital, supratrochlear, posterior auricular and occipital vessels usually allow scalp flaps with only a small pedicle to survive and large flaps to recover without complications 5,6 .
Most published cases of SCC have reported occurrence in the head and neck, with 8.3%-25.2% lesions occurring in the scalp. The current large numbers of living patients who underwent transplantation require more attention since immunosuppressants contribute to the formation of skin neoplasms.
The clinical recommendation for the margin of excision of SCC is 4 mm for low-risk patients and 6 mm for high-risk patients 7 . We use about 10 mm of margin based on the pathology, frequently removing the periosteum.
In case 1, local relapses and coalescence of premalignant lesions required a large excision. Although the large defect (16 x 16 cm) indicated the need for a microsurgical free flap, the chronic use of immunosuppressants, diabetes, and hypertension increases the risk of compromising the kidney transplanted 17 years ago in a longer surgery. We used two temporal-parietal-occipital rotation flaps for the reconstruction. The first, with a pedicle in the right temporal region, was rotated to cover the earliest portion of the defect. The second, lower and longer, with pedicle in the left temporal region, was rotated to occlude the posterior portion. The secondary occipital defect, with intact periosteum, received an inguinal total skin graft. In the postoperative period, epidermolysis and superficial necrosis occurred on the distal margin of the first flap. They were treated by debridement with hyaluronidase and outpatient cleaning, followed by dressings with Rifamycin and, finally, by colloidal occlusive dressings, showing excellent results.
Chronic use of methotrexate in patients with severe rheumatoid arthritis causes immunosuppression (case 2). After excision of the lesion, two randomized flaps were used: one larger and longer on the right with occipital pedicle, and one smaller on the left with temporal pedicle.
Distal suffering occurred in the flap on the right, leading to bone exposure and gap. With local anesthesia, a small flap of adjacent galea was rotated and sutured over the exposed bone. Using occlusive hydrocolloid dressings, epithelialization from the galea completely repaired the defect. This case illustrates the high safety of the pediculated flap in the temporal vessels and the high epithelization capacity of the galea.
Case 3, who underwent liver transplantation, received surgical treatment similar to case 2. But in this case, the right flap of the occipital pedicle was shorter, and there were no complications.
In case 4, temporal, frontal, and occipital scars limited the use of flaps. Tissue expansion was the option chosen in the absence of microsurgical resources in a local public hospital in the 1980s. This technique was recommended by Sasaki in 1985 8 , Anger in 1988 9 , and other authors 10 , followed by cranioplasty Korloff et al., 1973 11 and some osteosyntheses with steel wires. Despite the extrusion of one synthesis and a small bone fragment, it had no relapse of the fistula, with adequate protection to the brain and excellent aesthetic results. This case illustrates the use of an expanded advancement flap in the unpredictability of temporal flaps.

CONCLUSION
The experience gained in the surgical treatment of these complex and unusual cases indicates the preferred choice of random-pattern large fasciocutaneous flaps with temporal pedicles in the reconstruction of large scalp defects over microsurgery. Distal ischemic suffering may occur in these flaps, but when they are adequately treated, as in the cases presented, excellent aesthetic and functional results are achieved.

COLLABORATIONS JWF
Analysis and/or data interpretation, C o n c e p t i o n a n d d e s i g n s t u d y,