Salvage Free Tissue Transfer for Clival Osteoradionecrosis After Repeat Proton Beam Therapy

Multidisciplinary Management of Total Anterior Skull Base Osteoradionecrosis

Cases of delayed osteoradionecrosis (ORN) of the anterior skull base have unique management considerations. A 59-year-old woman with a history of basaloid squamous cell carcinoma of the sinonasal cavity with intracranial extension through the anterior skull base developed delayed radiation sequelae of anterior skull base ORN. She underwent an initial endoscopic resection in 2011 with persistent disease that required an anterior craniofacial resection with left medial maxillectomy in 2012. She had a radiologic gross total resection with microscopic residual disease at the histologic margins prompting adjuvant chemoradiotherapy to target volume doses of 66 to 70 Gy with concurrent cisplatin chemotherapy. She subsequently developed an intracranial abscess in 2021 along the anterior skull base that required a craniotomy and endoscopic debridement. Despite aggressive surgical and medical therapy, she had persistent intracranial infections and evidence of skull base ORN. She ultimately underwent a combined open bifrontal craniotomy and endoscopic resection of the necrotic frontal bone and dura followed by an anterolateral thigh free flap reconstruction with titanium mesh cranioplasty. The patient recovered well from a microvascular free-tissue reconstruction without concern for cerebrospinal fluid leak. Anterior skull base reconstruction with free tissue transfer is a commonly utilized method for oncologic resections. Here, an anterolateral free flap was effectively used to treat an anterior skull base defect secondary to a rare indication of skull base ORN.

Endoscopic Endonasal Repair of Recurrent Cerebrospinal Fluid Leak With Adipofascial Anterolateral Thigh Free Flap: Case Report and Review of Literature

Background. Cerebrospinal fluid leaks are the most common complication of endoscopic endonasal skull base tumor resection. The workhorse nasoseptal flap or other vascularized intranasal flaps may not be a viable option in patients who have previously undergone surgery or local radiation; in these cases, pericranial flaps may also be unavailable. Free flap reconstruction in patients undergoing endoscopic resection is challenging because of limited exposure. The transmaxillary approach has recently been reported for free flap reconstruction of these defects. This report describes a patient with a pituitary tumor who underwent craniotomy and resection of a pituitary mass via an endoscopic endonasal approach. Postoperatively, the patient developed a high flow cerebrospinal fluid leak that did not resolve with lumbar drain and attempts at endoscopic revision of nasoseptal flap. An adipofascial anterolateral thigh free flap was harvested, based on the descending branch of the lateral circumflex femoral vessels. An upper gingivobuccal sulcus incision was used to access the maxilla. Openings were created in the anterior and medial maxillary sinus to create a passage to the sphenoid sinus. The flap was inset into the defect via this transmaxillary channel. The pedicle was tunneled subcutaneously through the cheek to recipient facial vessels. The procedure resulted in complete resolution of cerebrospinal fluid rhinorrhea and pneumocephalus. Imaging at 18 months showed the flap in good position. This report describes the technique in detail along with a review of the current literature.

Treatment Outcomes for Osteoradionecrosis of the Central Skull Base: A Systematic Review

Objective Osteoradionecrosis (ORN) of the skull base can have catastrophic consequences if not detected early and managed appropriately. This is a systematic review of the different treatment modalities for skull base ORN and their outcomes.

Study Design This study is a systematic review.

Materials and Methods Two researchers extracted information including patient population, surgical technique, outcomes of interest, and study design. A computerized search of Medline, Embase, and the Cochrane library (January 1990–June 2020) looked for several papers on the subject of skull base ORN.

Results A total of 29 studies had met inclusion criteria, including data from 333 patients. Nasopharyngeal carcinoma was the most common primary tumor (85%). Average age at diagnosis of ORN was 55.9 years (range = 15–80 years) and 72.3% of patients were males. The average time to diagnosis of ORN after radiation therapy was 77 months with an average radiation dose of 76.2 Gy (range = 46–202 Gy). Nighty-eight patients (29.4%) also had chemotherapy as part of their treatment regimen. Although all parts of the central skull base were reported to be involved, the clivus and sphenoid bone were the most commonly reported subsites. Trial of medical treatment had a success rate of 41.1%. About 66% of patients needed surgical treatment, either primarily or after failing medical treatment. Success rate was 77.3%. Overall, the surgical treatment was superior to medical treatment (p < 0.0001).

Conclusion ORN is a rare complication of the treatment of skull base tumors. Most cases require surgical treatment, including endoscopic debridement or free flap reconstruction, which has a high success rate.

Level of Evidence Level 3 evidence as a systematic review of case studies, case reports, retrospective, and prospective trials with no blinding or controls.

Free tissue transfer for central skull base defect reconstruction: Case series and surgical technique

OBJECTIVES

Local reconstruction of central skull base defects may be inadequate for large defects or reoperative cases; free tissue transfer may be necessary. Inset of the flap and management of the pedicle can be challenging. We report our experience and approaches.

METHODS

Retrospective review identifying seven patients with central skull base defects who underwent free flap reconstruction from 2016 to 2020.

RESULTS

Four patients with recurrent nasopharyngeal carcinoma, one with recurrent craniopharyngioma, one with clival-cervical chordoma, and one with meningioma of the middle cranial fossa were analyzed. Six defects were closed with an anterolateral thigh free flap and one with a radial forearm free flap. In two patients, the flap was secured in an onlay fashion to the defect via a Caldwell-Luc transmaxillary approach. In one patient, the flap was passed transorally, and the pedicle was delivered into the neck via Penrose drain. In two patients, a parapharyngeal technique and in two others, a retropharyngeal was used for nasopharyngeal inset with endoscopic assistance. There were no flap failures, with an average follow-up time of 20.1 (range 3.2-47.1) months. One patient required flap repositioning on postoperative day three due to midline shift and intracranial contents compression. The transoral inset flap necessitated flap repositioning on postoperative day 13 to improve the nasopharyngeal airway.

CONCLUSION

Free flap reconstruction of the central skull base is challenging, but transmaxillary, transoral, parapharyngeal, and retropharyngeal approaches can be used with endoscopic assistance to ensure secure inset flap and avoid airway obstruction.