Combined Approaches to the Skull Base for Intracranial Extension of Tumors via Perineural Spread can Improve Patient Outcomes

Introduction: Many neoplasms of the head and neck extend centripetally, gaining access to the central nervous system via nerves through the skull base foramina. Often patients with perineural spread have been excluded from aggressive interventions given the overall poor prognosis and technical difficulty with addressing the perineural components. However, in carefully selected patients combined surgical approaches can provide the greatest potential for disease control as well as neural decompression for symptom relief.

Methods: We performed a retrospective chart review of patients who underwent skull base approaches for resection of tumors with intracranial extension via perineural spread from 2011–2014. Chi-square statistical analysis were undertaken to determine if distributions of the different categorical variables listed in Table 1 differed from one another against the primary outcome variable of mortality. A MedLine search was conducted to analyze the available literature for current practices of surgical resection in cases with radiographically and/or clinically diagnosed perineural spread, especially as it related to surgical indications and outcomes.

Results: We reviewed 20 consecutive patients that presented with perineural tumor spread through the skull base who underwent surgical resection. After reviewing radiographic findings, prior histologic diagnoses from cutaneous biopsies, neo-adjuvant therapies, and affecting symptoms, a total of 24 surgical operations were performed in the 20 patients with a multidisciplinary team of neurosurgeons, rhinologists, and head and neck surgeons. Eleven patients had endoscopic approaches to the sinuses, facial contents, and skull base, while half underwent transcranial approaches. 75% of patients had post-operative radiation treatment while half had chemotherapy. Based on patient reporting during post-operative visits we found 40% of our patients had a complete resolution of all their pre-operative symptoms without the development of new deficits, while another 45% had significant improvement in their presenting clinical conditions. Five patients experienced new post-operative deficits, most of which were expected and tolerable, such as V2 distribution numbness following neurectomy for pain relief, and hydrocephalus managed with shunting. During the treatment and follow-up period 3 patients experienced recurrence, which was treated with re-operation and/or additional adjuvant therapy, none-the-less two of them died during the study period. The overall mortality rate was 45% with an average life expectancy of 8.2 months (±5.4 months) from the time of presentation to our institution. Although not statistically significant, we found that after ~15 months from the time of surgery, the overall mortality leveled off.

Conclusions: Multifaceted approaches to intracranial lesions can be both safe and efficacious, especially for patients with intracranial extension via perineural spread. These surgeries are often performed with a multidisciplinary team, which allows both the extra- and intracranial disease to be addressed. In carefully selected patients, a combination of approaches has the added benefit of more direct approaches along the pathways of perineural spread and intracranial involvement. This can help improve patient outcome and provide symptom reduction in patients who otherwise have relatively poor quality of life.