Sensory complications in patients after scalp mass excision and its anatomical considerations

Abstract

Objective: To evaluate the incidence of postsurgical sensory complications in patients with scalp masses and classify the locations of them from a surgical standpoint according to anatomical considerations.

Methods: A total of 121 patients who underwent surgery for scalp mass were included in this study. The authors reviewed medical records and preoperative radiologic images. We investigated the complications related to sensory changes after procedure. Enrolled patients have been divided into three groups. Group A included patients with tumors above the superior nuchal line (SNL), Group B with tumors within the trapezius muscle area and patients who had tumors on the lateral trapezius muscle area were assigned to Group C. We compared the incidence related to postoperative sensory complications and summarized their additional treatments for these with clinical outcome.

Results: There were 12 patients (10%) with sensory complications related on the mass excision site (Group A: 1 patient, Group B: 2 patients, Group C: 9 patients). Six patients were affected with lesser occipital nerve (LON), 2 patients on greater occipital nerve (GON) and 4 patients on GON and LON. Over 6 months after surgery, two of the twelve patients with sensory complications did not have complete recovered pain in spite of proper medications and local chemical neurolysis with 1.0% lidocaine and dexamethasone.

Conclusion: Occipital neuropathy should be considered as a complication related excision of scalp mass. The sensory complications are more frequent in Group C because of the anatomical characteristics of the occipital nerves and there were no statistical difference for other variables.

Keywords: Greater occipital nerve; Lesser occipital nerve; Occipital nerves; Occipital neuralgia; Scalp mass; Third occipital nerve.

Fig. 1

To divide three groups according to anatomical locations of the scalp mass, there are two landmarks; superior nuchal line (SNL) and lateral margin of trapezius muscle (TPZ) indicated by black arrow. Group A: scalp mass located above the SNL. Group B: scalp mass existed within lateral margins of TPZ and below SNL. Group C: scalp mass located on neighbored TPZ and below SNL.

Fig. 2

We have explained anatomical considerations more affecting in the group C using schematic illustration of the occipital nerves. The main trunk of LON proceeds superficially along posterior margin of the sternocleidomastoid muscle (black arrow). The GON was found to emerge below to 30 mm from the occipital protuberance and laterally 15 mm from the midline on average. There are abundant sensory nerves above the superior nuchal line. GON: greater occipital nerve, LON: lesser occipital nerve, E: external occipital protuberance.