Simplified Treatment of Chronic Scalp Wounds With Exposed Skull

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Scalp wounds remain a common, often challenging problem for surgeons involved in the management of skin carcinomas. In the majority of patients, generous blood flow to the scalp generally allows for adequate healing when scalp reconstructions with local tissue flaps or skin grafts are performed. However, skin atrophy, recurrent surgeries, and radiation treatments to the scalp may complicate reconstructive options. Frequently, open wounds of the scalp will lead to desiccation of the pericranium and exposure of the underlying bone. When the skull is left exposed over an extended period, osteomyelitis of the skull often develops. Osteomyelitis further complicates the situation and when left untreated, may lead to systemic, life-threatening infection.

Throughout recorded history, treatment of scalping injuries has challenged physicians, and large scalp wounds were often considered grave, incurable conditions. Isolated references to treatment of the injured scalp and exposed skull can be found in writings dating back to Hippocrates.¹ His observations of skull anatomy accurately describe the skull-bone dipole and medullary bone ("soft, porous, sponge-like") positioned between the hard cortexes. He described trephination for head trauma and noted the "fleshy" tissue overgrowth at the sites of holes drilled into the skull. There is archaeological evidence from Italy, also from the 3rd century BCE, of a treatment of an unknown skull injury where linear cuts in the outer bone cortex were found.² It is theorized the linear cuts were made to treat exposed bone. Recognition of spontaneous granulation tissue developing from exposed medullary skull bone has been reported sporadically throughout medical history.

American medical texts dating back to the 18th century reference treatment of scalping injuries with exposed bone by removing the outer cortex of the skull. Rasping with a metal file or metal rasp was initially advocated as a means of removing the hard, outer cortex.³ Boring multiple holes or "pegging" with a metal awl or pointed instrument received support as an easier method of exposing the medullary layer.³ This methodology of cortical craniectomy for management of scalping injuries was not common knowledge among doctors at the time. Knowledge of the unique characteristic of spontaneous healing of exposed medullary skull bone was slowly disseminated through the centuries.

The American Civil War produced a large number of scalping injuries. Close fighting with bayonets and cavalry swords understandably generated significant scalp lacerations. Large caliber, low-velocity bullets often did not fully penetrate the skull but severely damaged the scalp and skull bone. The outer cortex of the skull was frequently damaged, exposing the medullary bone.^3,4 Spontaneous healing of the exposed medullary bone was observed, so Civil War surgeons began utilizing the technique of cortical craniectomy when treating large scalp wounds with skull exposure.

Surgeons of the late 19th and early 20th century routinely used cortical craniectomy as a treatment for exposed skull bone. However, as more modern and more sophisticated methods of scalp reconstruction developed, use of this simple technique diminished. Isolated case reports of the technique have been published as scientific articles recently.^5-8 Conservative approaches have been advocated for management of large scalp wounds.^9-13 The use of topical solutions, growth factors, and platelet-rich fibrin application has been shown to be helpful in healing difficult scalp wounds.⁹

A comprehensive review of cranial osteomyelitis revealed that an aggressive approach to treating infected skull bone limits life-threatening complications.¹⁴ The dangers of osteomyelitis after craniotomies and the surgical options for treating this serious complication are well represented in medical and surgical journals.¹⁴

Ingenious procedures using local scalp flaps, tissue expansion techniques, and microvascular free-flap transfer are available when conditions allow. However, a patient's medical circumstances may preclude complex surgical options. Currently, reconstructive surgeons rarely consider cortical craniectomy as an option. The technique, and possibly even awareness of the technique, has been lost to many contemporary surgeons.

Cortical craniectomy was used by the authors of the current case series in treating chronic scalp wounds with exposed skull bone in patients with complicated medical and surgical conditions for whom more complex reconstructions were precluded. The technique described in the current report was found to be simple and reliable in managing small and large scalp defects with exposed skull bone.

Elderly patients with areas of exposed, denuded skull bone and poor surrounding skin were chosen for cortical craniectomy as the preferred reconstructive approach. All wounds were chronic in nature and had resisted closure by other methods. Scalp wound reconstructions with local flaps or more complicated procedures were not chosen for a variety of reasons. The skin surrounding the defects in these patients was judged to be atrophic, thin, and marginally vascularized. Simple removal of the outer skull cortex was judged most appropriate for these frail, elderly, and infirm patients.

Patients underwent their initial procedure in the operating room for monitoring and conscious sedation. Intravenous, conscious sedation by an anesthesiologist was used, as was local anesthesia injection with 0.5% lidocaine and 1:200,000 epinephrine into the skin around the wounds. The local anesthesia was used to help reduce discomfort and bleeding of the surrounding skin.

A circulating drill with a grinding burr was used for removal of the outer cortical bone. The circulating burr was passed over the cortex until the medullary bone was exposed (Figure 1). Pinpoint bleeding from the medullary bone was observed when the appropriate level was reached. Care was taken when in an area of skull suture lines. The depth was lessened over the suture lines to prevent deep penetration of the skull and exposure of the dura. The burr was passed from the edge of the wound across the exposed bone with a gentle back-and-forth motion. Sterile saline was dripped over the burr to reduce bone dust scattering and heat production. Once the proper level of cortical bone removal was reached, the level was easy to maintain across the remaining defect. The so-called peanut burr was passed slightly beneath the skin edge of the perimeter of the wound for a few millimeters to facilitate epithelial overgrowth. Bone dust was aspirated with a smoke aspirator. Light electrocautery was used to staunch persistent oozing from the medullary bone.

After cortical craniectomy was complete, a generic petroleum-based antibiotic ointment was applied to the medullary bone surface and then covered with a light gauze dressing. Patients and their caregivers were instructed to lightly apply a generic antibiotic ointment daily to the denuded area and cover with dressings. Avoiding trauma to the delicate tissue overgrowth was advised. Cephalosporin antibiotics were used for broad-spectrum coverage. Intravenous antibiotics were given preoperatively, and oral antibiotics were given for 5 days postoperatively.

Patients were followed at weekly intervals to assess healing and to advise wound care. After approximately 2 weeks, a petroleum or aqueous moisturizing ointment was preferred over the antibiotic ointment to prevent skin hypersensitivity. For simplicity of wound care, patients were instructed to apply the ointments to the gauze and then apply the gauze directly to the wound. The ointment provided enough adhesion to secure the gauze and avoid the need for external taping or head wrapping. Patients were instructed to avoid steroid preparations because of the potential for interference in wound healing.

As healing progressed and patient comfort with the open wound normalized, patients were seen less frequently. Because of the COVID-19 pandemic, nursing care was less available, and progress was often followed by telephone contacts and photographs.

Informed surgical consents were obtained from each patient prior to surgery. The consents included an authorization of photography for documentation and medical education. The photographs used in this publication are restricted to the wounds, and no identifying characteristics are included. Ethical approval for the surgical procedures was not sought nor deemed necessary because the technique has historical significance and has been shown to be a successful method for treatment of exposed skull bone.

Eight patients with open skull wounds and exposed bone were treated over a 6-year period with cortical craniectomy. The exposed bone in these patients was devoid of all pericranium. Five male and 3 female patients with a mean age of 83 years (range, 72–96 years) comprised the group. All defects were subsequent to skin carcinoma removal, and initial reconstructions were attempted with either skin grafting or local skin flaps. Patients had atrophic surrounding skin, as evidenced by significant alopecia and observable scalp thinning. The wounds were present from 5 months to 4 years. The chronic wounds were managed with many weeks of conservative therapy with a variety of emollients and ointments by wound centers, with little progress observed. It was judged that healing had stalled and surgical intervention was appropriate.

The patients were elderly, frail, and judged to be poor candidates for general anesthesia and complex surgical reconstruction. They were diagnosed with a variety of medical problems, including arteriosclerotic heart disease, hypertension, chronic obstructive pulmonary disease, dementia, and type 2 diabetes. Insulin-dependent diabetes was not present in these 8 patients. Three patients lived in an assisted living environment with nurses to help with wound care, and the remaining 5 lived with family members who assisted with dressings.

The scalp wounds measured from 2.5 cm to 12 cm and were oval-shaped, and all involved the parietal bones. The largest defect, measuring 12 cm, occupied the vertex of the skull in a 92-year-old female, traversed the sagittal suture line, and included both parietal bones (Figure 2). Two patients had smaller defects located over the central sagittal suture line.

All wounds resulted after treatment of cutaneous skin cancers. Invasive squamous cell carcinoma was the diagnosis in 6 patients and basal cell carcinoma in 2. Osteomyelitis was identified in 3 patients since exudate was observed emanating from irregularities across the bone surface.

Two female patients received external beam ionizing radiation as adjunctive treatment for their invasive squamous cell carcinomas. Radiation changes were obvious in the surrounding skin. Thin, atrophic skin with no hair was seen around the large central defect of the 92-year-old female, and reddened, fragile skin surrounded the forehead defect in the 80-year-old female. This latter patient with exposed bone of the mid forehead had multiple forehead wounds that enlarged over a 6-month period. The radiation changes made the skin of her forehead inappropriate for direct or skin-flap closure.

All 5 male patients had alopecia and diffuse actinic changes of their thin, atrophic scalp skin. Four patients (2 male, 2 female) had numerous prior skin cancers of the face and scalp that required treatment in their past.

For most patients, the surgical time needed to remove the cortical bone was less than 30 minutes. The large 12-cm scalp wound required approximately 1 hour for cortex removal. Recognition of the difference in the bone consistency over the suture lines was easy to distinguish. Depth of bone removal was less over the suture lines. Pinpoint bleeding was observed from the denuded bone along the suture line, but it was less than what was observed with the more vascular medullary bone. Relatively minor and self-limited bleeding was observed from the exposed medullary bone. Spot cautery was occasionally needed to help with persistent oozing. Penetration of the inner bone cortex and exposure of the dura did not occur.

Once the bone removal was complete, antibiotic ointment and a light gauze dressing were applied. Daily wound care consisted of ointment application and wound cover to prevent desiccation and to keep the gauze dressing adherent to the rough medullary surface. The moist ointment provided a satisfactory environment for granulation tissue development.

Granulation tissue was observed to develop within the first 2 weeks after cortical bone removal. The tissue appeared diffusely over the entire area of medullary bone. By 4 weeks, the granulation tissue covered the entire wound. Small sites of exposed bone because of inadequate removal ultimately became covered with developing tissue.

Two patients had persistent, residual bone spicules or small islands of bone that remained exposed for more than 8 weeks. These small areas were removed in the office procedure room with a rotating drill and burr and no local anesthesia (Figure 3). No tenderness was experienced by these 2 patients. However, they did sense an annoying vibration.

Epithelialization across the granulation base occurred steadily over a period of weeks to months. Epithelium streamed from the wound edges at the periphery. The smaller wounds were covered with epithelium by 2 months (Figure 4, Figure 5). The larger wounds required longer healing durations. Trauma to the delicate developing tissue interfered with epithelialization, and gentle ointment application and minimal cleansing were advised. Peroxide cleansing appeared to impair healing and was discouraged. The bony suture line areas developed an epithelial cover similar to the rest of the exposed medullary bone. No skin grafting was used in these patients.

The 92-year-old female with the largest wound (8 cm × 12 cm) had undergone irradiation as adjunctive therapy for her skin cancer approximately 6 years previously. She had a discolored, irregular segment of skull exposed for more than 4 years and had developed a persistent malodorous drainage from multiple sites. These sites with drainage were obvious areas of osteomyelitis (Figure 6A). She wore a hairpiece to cover her head and hide the wound. She had experienced 2 episodes of septicemia that required inpatient antibiotics. She was prescribed oral antibiotics intermittently to reduce the malodorous exudate and suppress infection.

This patient had been evaluated at a local university for reconstruction of her scalp using microvascular surgery and free tissue transfer but was judged to be a poor candidate. She was referred to the senior author (J.E.G.) for wound care. Cortical craniectomy was offered as a less involved, more reasonable option to address the exposed skull and chronic osteomyelitis. Cortical craniectomy was performed under light conscious sedation, and the infected outer cortex was easily removed (Figure 6B).

Despite the large open area, granulation tissue development progressed normally (Figure 6C). The patient and a caregiver were managing the wound well, and a moist environment over the exposed bone was maintained. The patient continued to wear her hairpiece comfortably. By 4 months post craniectomy, the majority of the wound had epithelialized (Figure 6D). All spicules of bone eventually developed a cover. The epithelium across the wound proved delicate, and small abrasions were common. The abrasions healed, and durability of the new skin improved with time.

Removal of the chronically infected skull bone appeared to help improve the patient's overall health. Her caregiver related a subjective improvement in the patient's energy and appetite. The wound was judged to be totally healed by 6 months.

Cortical craniectomy was performed to treat exposed frontal bone of the mid forehead in the 80-year-old female patient who had received radiation after recurrence of a squamous cell carcinoma. The forehead skin from eyebrow to hairline exhibited an irritated, reddened appearance from radiation injury. The forehead wounds progressed over 2 months, with eventual frontal bone exposure. Minor trauma to the forehead was followed by skin necrosis and development of a 5 cm–wide wound and 3 small 1-cm openings (Figure 7A). The skin was mobile around the largest opening, with undermining for another 1 cm around the defect with bare bone and no periosteum. Approximately 6 months after the patient's forehead healing stalled, cortical craniectomy was judged appropriate.

The outer bone cortex was removed without difficulty, and some granulation was observed to develop over the exposed medullary bone by 4 weeks (Figure 7B). However, skin necrosis began along the medial edge and the skin wound slowly enlarged. Minimal epithelialization was observed, and wound healing stalled. A skin biopsy of the medial forehead revealed recurrence of squamous cell carcinoma. The patient subsequently developed lymphadenopathy of her neck and underwent lymphadenectomy and neck node irradiation. The forehead wound with the exposed medullary bone was managed conservatively, and minimal epithelium at the edges developed. The patient's carcinoma advanced, her medical condition slowly worsened, and she died after a 2-year period. This was a healing failure of cortical craniectomy of frontal bone of the forehead. While the exposed medullary bone developed granulation tissue overgrowth, the wound did not develop significant epithelium. Radiation, poor nutrition, and skin cancer recurrence complicated wound healing in this patient.

In 7 of the 8 patients with exposed skull bone in the current case series, cortical craniectomy was successful in healing the scalp wounds. Medullary bone healing progressed steadily and without complications with conservative wound therapy. No osteomyelitis developed in this group, and the 3 patients with preoperative osteomyelitis healed without evidence of residual infection. Removal of the infected outer cortex was sufficient to treat the established osteomyelitis.

Scalp atrophy with reduction of vascularity is seen in elderly individuals, and these changes often complicate wound healing when surgery is performed. Treatment of skin cancer of the scalp is often complicated by failure of a reconstruction effort. An open wound of the scalp skin may progress, exposing the pericranium and leading to desiccation and skull exposure. The resultant exposure of skull bone with atrophic surrounding scalp may pose a difficult problem for the reconstructive surgeon.

Treatment of scalping injuries and exposed skull with cortical craniectomy has been referenced throughout medical history. Sporadically, the technique of outer cortex removal was used by knowledgeable surgeons to treat the exposed skull. However, modern surgical techniques have relegated this simple technique to distant, sometimes lost, memory.

The current case series discusses 7 elderly patients with various size skull exposures who were successfully treated with cortical craniectomy over 6 years. The patients tolerated the procedures under mild conscious sedation and local anesthesia. The technique of cortical craniectomy required minimal surgical time, and the medullary bone was easily exposed with a rotating burr. The uncovered medullary bone healed with conservative therapy. Despite sound evidence that wound healing can be maximized with more complex methodology and product applications, simple moisturizing products were preferred in this group of elderly patients. The moist environment proved effective in promoting wound healing.

Granulation tissue developed diffusely across the medullary surface, and after a few weeks the exposed medullary bone was covered. Epithelialization developed from the edges and marched across the open wounds over weeks to months. Understandably, the larger wounds took longer for the epithelium to advance and cover. The conservative therapy with a moist environment and simple dressing allowed the wounds to heal. Minor trauma easily damaged the developing epithelium, but durability of the delicate surface skin improved with time.

Secondary bone removal of small residual sites allowed for more rapid healing and should be considered if areas of cortical bone are left after the initial procedure. The skull bone proved insensate, and removal of small areas of residual bone was painless.

Previous reports have included removal of the outer cortex of the skull with a circulating burr as an effective method of treating chronic scalp wounds with exposed bone when a conservative approach failed.^8,9 A platelet-rich fibrin application was successfully used to help close 16 chronic scalp wounds, 8 of which had exposed skull bone.⁹ These 8 wounds with exposed bone were not described specifically. The size of the wounds and time to healing were not explained. In that report, 6 wounds were treated with outer cortex removal, but these cases of cortical craniectomy were not separated from the group. Collectively, granulation tissue developed over an average of 7.4 weeks and epithelialization was complete after an average of 14.6 weeks. The development of granulation tissue and epithelium of these patients varied greatly, with complete healing requiring up to 44 weeks in 1 patient. Two patients died before the wounds were totally healed. The size and time for healing of the 6 patients who underwent outer bone cortex removal were not delineated. The steady development of granulation tissue and epithelium was observed to be similar in the current case series.

While it was suggested in 1 report that preoperative CT of the calvarium was necessary to assess the thickness of the skull,⁵ no radiological tests were used to evaluate bone thickness in the 8 patients in the current report. A skull deformity or an area of the skull previously involved in trauma may necessitate a radiologic evaluation. However, the skull dipole is a reliable anatomic feature, and a routine CT scan should not be necessary.

A large study of so-called secondary intention healing with scalp and forehead wounds reported a 90% success rate with a conservative approach involving "pulse-string" suturing around the wound, wound cleansing, and petrolatum ointment preserving a moist environment.⁸ Seventeen patients had exposed bone with no periosteum. All but 4 patients healed with their wound treatments, and 3 eventually underwent removal of the outer bone cortex of the skull. For these 3 patients, the average time to granulation was 92 days and epithelialization covered the area at an average of 186 days. The sizes of the wounds were not described. Skin grafting was eventually used to close these 3 wounds. However, the time to grafting was not explained.

Granulation tissue development in the larger case series by Wong and Zloty⁸ was reported to take longer than what was seen in the patients of the current case series. In the current case series, granulation tissue developed rapidly after craniectomy, and by 1 month all patients had a cover of the medullary bone. Even the forehead wound with radiation exposure and with minimal epithelial progress over 2 years developed a layer of granulation tissue by 4 weeks after craniectomy and subsequent management with daily application of ointment and wound cover.

Epithelialization in the current case series was seen to progress from the periphery, as described in other reports.^8,9 The large 12-cm wound of the 92-year-old female patient was judged to be covered with epithelium by 4 months after craniectomy, except for a few bone spicules. The epithelial cover of the spicules was not measured exactly, but the wound was reported to be completely healed by 6 months. The smaller wounds in this case series epithelialized by 2 months. The times for epithelial healing appear to be similar to what has been observed in other studies.^9,11

Skin grafting has been described as a successful procedure to effectively reconstruct an area covered with granulation tissue after cortical craniectomy.^6,7,9 The vascularized granulation tissue emanating from the medullary bone affords a healthy matrix for epithelium to spontaneously stream across. Wound healing progressed with the simplified approach of the current case series, and skin grafting was not deemed necessary.

Osteomyelitis of the outer cortical bone can be successfully managed with removal of the infected cortex. The medullary bone is well vascularized and appears resistant to infection. The 3 patients with osteomyelitis in the current series responded to the simple removal of the outer cortex. This is the experience of other surgeons who have encountered similar instances of isolated skull osteomyelitis.¹⁴

The forehead frontal bone treatment of 1 patient in the current series was not successful. Granulation tissue developed, but minimal healing progression occurred. Radiation and patient disease complicated the forehead healing. The authors of this case series maintain that cortical craniectomy should successfully allow for healing in the forehead area in most situations.

Exposed skull bone is prone to desiccation, eventual breakdown, and subsequent osteomyelitis if left uncovered.¹⁴ Atrophic scalp skin, radiation injury, and scarring from multiple surgeries may limit local reconstructive options. Complex reconstructions involving muscle flaps or free tissue transfer may not be appropriate for elderly and infirm patients. Cortical craniectomy of the exposed skull bone is a simple, direct technique that allows for secondary healing. It should remain a valuable option of the reconstruction surgeon for treating difficult scalp wounds with exposed skull bone.

This retrospective review of treatment of a heterogeneous group of elderly patients with chronic wounds with skull bone exposure has several limitations. The variables of age, complex medical problems, and size of the wounds are not delineated. The specification of these variables would not add to the explanation or understanding of the surgical management. All patients were treated with simple removal of the outer cortex of the skull and application of a moist environment with a light gauze dressing. There was no effort to optimize formation of granulation tissue and epithelial coverage by using products proven to accelerate wound healing. Skin grafting was not performed to shorten wound healing. Postoperative care was kept uncomplicated to accommodate the elderly patients and their caregivers.

Chronic wounds with skull bone exposure often present a difficult challenge to the reconstructive surgeon. Removal of the avascular outer skull bone cortex allows for granulation tissue development from the vascular medullary bone. This bone removal is efficiently achieved with a rotating burr, local anesthesia, and minimal sedation in an elderly patient despite a complex medical history. Conservative wound management allows for granulation tissue development, epithelial streaming, and wound closure. This simplified technique proved successful in 7 patients. One failure occurred in a patient with skin irradiation, recurrent skin cancer, and generalized debility with worsening malnutrition.

Complex surgical reconstruction of a chronic wound with skull bone exposure may not be appropriate in elderly, infirm patients. A relatively conservative approach with simple removal of the outer bone cortex will facilitate wound healing. This technique should remain a valuable option for the reconstructive surgeon.

Authors: John E. Gatti, MD and Robert B. Sollitto, MD

Affiliation: Voorhees Surgery Center, Division of Plastic Surgery, Virtua Medical Center, Voorhees, NJ 

ORCID: Gatti, 0000-0002-7686-5807

Disclosure: The authors disclose no financial or other conflicts of interest. Data were presented in part at Plastic Surgery The Meeting, September 28-October 1, 2018, Chicago, IL (“Cortical Craniectomy for the Treatment of the Exposed Skull”). 

Correspondence: John E. Gatti, MD; 250 W. Spring Street, #725, Columbus, OH 43215; jgattimd@aol.com

Manuscript Accepted: July 12, 2024