Extended Scalp Flaps for Extensive Soft Tissue Scalp Defects as a Day Surgery Procedure Under Local Anesthetic: A Single Centre Experience

Abstract

Background  Cutaneous malignancies are on the rise, associated with an increased number in scalp cancers that require wide local excision (WLE) to ensure clearance; the inelastic nature of the scalp poses a particular challenge when dealing with such large defects.

Case presentation  A series of 68 cases with large scalp defects following WLE for the clearance of squamous cell carcinoma, atypical fibroxanthoma, dermatofibrosarcoma protuberans, and melanoma skin cancers are presented. These cases were treated in one center under local anesthesia and underwent extended scalp flaps to close the resulting defect primarily without the use of skin grafts for the flap donor site on the scalp.

Conclusion  Extended scalp flap is a safe and reproducible solution for extensive scalp defects, which results in quicker wound healing with cosmetically superior results, and can be performed safely and comfortably under local anesthesia in the day case setting.

Introduction

The incidence of head and neck skin cancers is on the rise in an overall increased trend for cutaneous malignancies. ¹ The scalp is a particularly vulnerable region which frequently affected by skin cancers such as most commonly squamous cell carcinoma, basal cell carcinoma, and melanoma. If left untreated, such malignancies can grow through the various tissue planes and extend through the cranial bones. Wide local excision (WLE) is therefore recommended for such malignancies and, given the often sizeable recommended peripheral margins, this may result in a large defect. Due to the lacking soft tissue elasticity, such defects are difficult to reconstruct. In addition, achieving clearance of tumors that have invaded through the periosteum requires removal of the outer table of the skull by the use of a drill.

The aim of scalp reconstruction is to close the resulting defect of the WLE completely, with a robust and well-vascularized layer of tissues, allowing for early adjuvant radiotherapy if indicated. The various existing solutions include skin grafting locoregional flaps as well as free tissue transfers.

Skin grafts prove ineffective in the absence of the periosteal layer from which a skin graft would normally draw its nutrients ensuring an adequate graft survival, and so large defects which have necessitated removal of this layer are not suitable for grafting.

Various local flaps have been described including the pinwheel flap or the O-Z closure. ^{2 3} Such local flaps have the advantage of being reliable with a minimal donor site morbidity and excellent color match.

Free tissue transfers import a volume of tissue from a distant anatomical area and can be sized according to the defect ensuring adequate tissue availability. Flaps that have been described for scalp reconstruction include anterolateral thigh, radial forearm, and latissimus dorsi free flaps. ^{4 5 6} Their main drawback is lengthy operative time and increase stress on the patient's reserves that are often already limited. ⁷

The author describes the use of extended scalp flaps associated with extensive undermining of the scalp to safely reconstruct large full thickness scalp defects following resections of squamous cell carcinoma (SCC), atypical fibroxanthoma (AFX), or melanoma skin cancer. In cases involving the pericranium, the outer table of the skull had been removed ( Fig. 1 ) and all performed under local anesthesia in day-case setting. This results in direct closure of the wound, without the need for a skin graft to the donor site. The flap design is oriented in a versatile way to utilize the robust vascular territories of the scalp, ensuring flap survival.

Fig. 1.

Case 1: Left parietal scalp closure after resection of malignant skin lesion.

Methodology

We prospectively collected data on 68 patients, who underwent WLE for SCC, AFX, dermatofibrosarcoma protuberans (DFSP), or melanoma, with or without drilling of the outer table of the skull as required between October 1, 2016 and June 30, 2019. All were operated upon by the same surgeon in one center under local anesthesia in a day-case setting. As per routine practice, options for repair of the resulting defect had been carefully considered and discussed with the patient, and all of those for whom extended flap repair was clinically indicated were included. The main aim of reconstruction was to achieve robust wound closure that would allow early postoperative radiotherapy if indicated ( Fig. 2 ).

Fig. 2.

Case 2: Left frontoparietal scalp resection after resection of malignant skin lesion.

Parameters collected include age, gender, American Society of Anaesthetists (ASA) grade, defect size, total operative time (skin incision to skin closure), length of hospital stay (in hours), and postoperative complications.

The operative steps include:

• Infiltration of 5 mg/kg local anesthetic (xylocaine; lidocaine 1% with epinephrine 1:200,000) diluted with 0.9% normal saline in a ratio 1:1 provided local anesthesia. Patient's weight ranged between 60 and 120 kg and average 70 mL. Total volume infiltrated therefore ranged between 60 and 120 mL and average 70 mL.

• WLE with appropriate peripheral skin margins depending on pathology (6 to 10 mm for SCC; 5, 10, or 20 mm for WLE of melanoma (depending on Breslow thickness); 10 to 20 mm for DFSP and AFX including periosteum ( Fig. 3 ).

• Drilling of the outer table (with a size 7 burr) in cases where the periosteum was breached ( Fig. 4 ).

• Measuring of defect and design of scalp flap

• Flap elevation

• Scalp degloving of the adjacent scalp skin, superficially to the pericranium, as far laterally as needed ( Fig. 5 ).

• Rotation of flap into defect and meticulous hemostasis

• Closure of wound with temporary anchoring size 2 silk sutures followed by clips.

Fig. 3.

Case 3: Left frontoparietal scalp reconstruction.

Fig. 4.

Case 4: Frontal scalp reconstruction.

Fig. 5.

Case 5: Left parietal scalp reconstruction.

Postoperative care:

• Co-codamol 30/500 PO QDS PRN for 7 days for pain relief

• Flucloxacillin 500 mg PO QDS for 7 days or clarithromycin 500 mg BD for 7 days if penicillin allergy.

Results

The age range of our patients was between 58 and 99 years of age with the mean age being 78 years, with 63/68 cases (93%) above the age of 75.

The intervention was performed on 63 men and 5 women, with 18/68 (29%) cases having an ASA of 1, 42/68 (62%) cases having an ASA of 2, and 8/68 (12%) cases having an ASA of 3.

All cases underwent the procedure under local anesthesia.

The size defect ranged from 12 to 115 cm ² , with the mean size being 41 cm ² , and 32/68 (47%) cases required drilling of the outer table of their skull ( Fig. 4 ).

Cancer clearance was achieved 100% of cases with 51/68 (75%) SCCs, 4/68 (6%) AFXs, 4/68 DFSP (6%), and 9/68 (13%) being melanoma skin cancers ( Fig. 5 ).

There were no intraoperative complications, and the procedure was well tolerated by all patients.

The operative time ranged from 32 to 65 minutes with 61/68 interventions (90%) requiring less than 45 minutes.

A total 65/68 (96%) of patients were discharged from the day surgery within 5 hours from admission and 3/68 (4%) cases required overnight admission due to social reasons but were discharged in less than 23 hours (day case criteria).

A total 63/68 (93%) of patients had a postoperative standing cone/dog ear at the pivot point which settled down completely in all cases within 6 weeks.

Two patients had distal flap necrosis, resulting in exposed bone (2 × 3 cm), and two cases suffered wound dehiscence; all healed by secondary intention within 12 weeks (chloramphenicol ointment was applied once daily and mepilex border was used as dressing and changed every 72 hours). Of these, four cases only one required postoperative radiotherapy; this complication resulted in delayed administration of the radiotherapy by 4 weeks.

A total 40/68 (59%) of patients proceeded to require postoperative radiotherapy.

Follow-up was at 1 week after surgery (mean = 7 days, range = 6–14 days) and regularly until 8 weeks after surgery in 64/68 (94%) cases and until 12 weeks in 4/68 (6%) cases.

Discussion

The main reconstructive options for scalp include healing by secondary intention, primary closure, skin grafting, local flap coverage, and free flap reconstruction. ⁸

The simplest approach is healing by secondary intent, as it is limited to the excision of the pathology, followed by application of dressings. This is best suited for candidates with numerous comorbidities; a prerequisite is that the pericranium is left intact to allow reepithelialization. The disadvantages of secondary intention healing include prolonged time for wound healing resulting in delay of adjuvant radiotherapy, as well as a bald patch, which ultimately results in an inferior cosmetic result. It is worth noting that wounds that heal through secondary intention result in a scar size of 60% of the initial wound size due to the phenomenon of scar contraction. ⁹

The tight structure of the scalp lakes makes direct closure difficult due to the high tissue resistance. The main advantage is simplicity of the procedure if adequate undermining has been performed; usually defects of less than 3 cm ² are amenable to direct closure. ¹⁰

Skin grafting in the presence of intact pericranium is a commonly used technique for the reconstruction of larger scalp defects, with the main advantage being a shortened operative time. This is especially suitable for high-risk patients with medical comorbidities; an additional advantage of skin grafting allows postoperative surveillance, following resection of high-risk pathologies such as SCC and melanoma, ¹⁰ with minimal graft donor site morbidity.

Local flap reconstruction has several advantages, including good color match, contour, and texture match. The three categories of local flap reconstruction include advancement, transposition, and rotation: advancement flaps have a limited role in scalp reconstruction due to the limited elasticity and high tension in the scalp which prevents axial advancement of the tissues. Transposition flaps involve transferring tissue over or under intervening tissue. The lack of tissue laxity interferes with and limits the ability to transpose tissue. Transposition flaps for scalp reconstruction include the temporoparietal flap, the temporoparietal-occipital (Juri flap), and the parietal temporal postauricular vertical flap. ¹¹ Scalp transposition flaps may be based on the (supratrochlear artery [anteriorly], the superficial temporal artery [laterally], or the occipital artery [posteriorly] rotational flaps, as utilized in our cohort, are the most versatile pattern for local flap reconstruction of the scalp, particularly if the defect exceeds 3 cm ² . ¹² Larger defects on the scalp require an arc incision that is up to six times the greatest diameter of the defect. ¹¹ A “back-cut” may be utilized if undermining alone is insufficient. Special care must be taken so as not to distort the hairline, as this would result in a worse cosmetic outcome. An additional technique that has been shown to reduce the wound closure tension by up to 40% ¹³ is judicious galeal scoring, parallel to the arterial supply of the flap.

Free tissue transfer is a suitable reconstructive choice for larger scalp defects that exceed 120 cm ² , or resections that result in exposed vital structures. Both muscle only and fasciocutaneous flaps have been described, including latissimus dorsi (with split skin graft coverage), anterolateral thigh flap, radial forearm flap, and rectus abdominis flap. ¹⁴ The main disadvantages of free flap reconstruction include long operative time with the inevitable increased anesthetic risk ¹⁵ to the patient, the possibility of flap failure which would necessitate further flap harvesting, with the unavoidable increase in risk and morbidity to the patient. ¹⁶

We report a series of 68 patients who received a scalp flap that resulted in a successful and reproducible pattern that was safe and gave a cosmetically acceptable result. Our patient group had an increased ASA (3), as well as a relative increased aged (mean = 78 years), which made it important to avoid general anesthesia where possible. One of the key benefits of this procedure is that large scalp reconstruction can be performed under a mixture of regional anesthesia, achieved by selective nerve blocks such as the supra orbital, supra trochlear, superficial temporal, and the occipital nerves, as well as local infiltration of the tissues along the lines of planned incision.

Key to a successful direct closure with minimal tension was extensive undermining of the surrounding scalp skin, superficial to the pericranium, until wound closure was possible.

The elevation of the scalp flap—in combination with extended degloving of the peripheral scalp to allow direct closure of the donor site—is relatively simple and results in less operative time and no donor site morbidity compared with regional flap associated with superficial skin graft or free flap techniques. The average operative time for this intervention was 40 minutes, with all cases being discharged in under 6 hours except for two cases that were kept in overnight and discharged after review the following morning (<23 hours).

Conclusion

Extended scalp rotation flap with extensive undermining of the scalp—with or without burring of the outer table of the skull—is a safe and reproducible solution for extensive scalp defects. This technique renders the use of split skin grafts for the scalp flap donor site superfluous, results in quicker wound healing with cosmetically superior results, that can be performed safely and comfortably under local anesthesia in the day case setting