case report

Draf Type III Surgery for Delayed Formation of Lateral Frontal Sinus Mucocele with Repeated Inflammation Following Frontal Craniotomy: Case Report and Literature Review

Tessei Kuruma1*, Kenichirou Iwami2, Mariko Arimoto1, Kinga Yo1, Yuka Kawade1, Yutaka Kondo1, Yasue Uchida1, Tetsuya Ogawa1, Yasushi Fujimoto1

1Department of Otorhinolaryngology, Head and Neck Surgery, Aichi Medical University, Aichi, Japan

2Department of Neurosurgery, Aichi Medical University, Aichi, Japan

*Corresponding author: Tessei Kuruma, Department of Otorhinolaryngology, Head and Neck Surgery, Aichi Medical University, 1-1 Yazakokarimata, Nagakute-shi, Aichi 480-1195, Japan

Received Date: 09 August 2022

Accepted Date: 13 August 2022

Published Date: 17 August 2022

Citation: Kuruma T, Iwami K, Arimoto M, Yo K, Kawade Y, et al (2022) Draf Type III Surgery for Delayed Formation of Lateral Frontal Sinus Mucocele with Repeated Inflammation Following Frontal Craniotomy: Case Report and Literature Review. Ann Case Report 7: 909. DOI:


The complication of frontal sinus mucocele can occur long after craniotomy. We experienced a 77-year-old woman who developed recurring sinusitis due to delayed formation of a mucocele in the right frontal sinus at 20 years after frontal craniotomy. Following right frontal sinus surgery performed through a Killian incision, the frontal sinusitis recurred, but showed improvement after endoscopic modified Lothrop procedure (Draf type III surgery). Frontal sinus mucocele can occur due to residual mucosa in the frontal sinus or as an inflammatory reaction due to filling material in the frontal sinus. Prior to operating on a frontal sinus mucocele after craniotomy, it is necessary to discuss the surgical approach thoroughly with the neurosurgeon to confirm whether the primary site of inflammation is in the frontal sinus, and to decide whether the endoscopic modified Lothrop procedure (Draf type III) should be used alone or in combination with frontal sinus surgery via a coronal incision on the scalp as the surgical approach. Preoperative image-based simulation was very effective in the present case. Draf type III, using a navigation system and a frontal sinus punch, is considered a very safe surgical technique for frontal sinus mucocele that is unlikely to cause closure of the nasofrontal canal.

Keywords: Frontal sinus mucocele; Endoscopic sinus surgery; Endoscopic modified Lothrop procedure (Draf type III); Frontal sinus punch


The frontal sinus is frequently a troublesome anatomical obstacle to gaining access to the medial anterior cranial base. In the setting of craniotomy, complications after traversing the frontal sinus can lead to mucocele formation and frontal sinusitis. Violation of the frontal sinus during craniotomy can result in mucocele formation as an early or late sequela. Image guidance may help avoid unnecessary frontal sinus violation. As mucoceles may develop decades after the initial frontal sinus violation, long-term follow-up with imaging is recommended. The endoscopic endonasal approach is generally preferred for treating these lesions; however, it may be necessary to perform obliteration or cranialization in certain situations [1]. Delayed onset of frontal sinusitis after craniotomy is often refractory. In cases where the cause of infection was bone wax, endoscopic modified Lothrop procedure (EMLP/Draf type III, hereafter termed Draf type III) has been reported to result in remission [2]. In contrast, several reports have indicated that control of infection is difficult by Draf type III alone in the case of combined infection of artificial materials such as titanium plates, artificial bones, and bone valves in addition to bone wax infection. In these studies, frontal sinus surgery via a coronal scalp incision or coronal incision of the forehead was also necessary [3,4]. We report a case of recurrent frontal sinusitis caused by a delayed frontal sinus mucocele that had first occurred as frontal sinusitis immediately following craniotomy, which was eventually cured by the Draf type III procedure.

Case Presentation

A 77-year-old woman had undergone anterior craniotomy to remove an olfactory fossa meningioma 31 years ago at the Department of Neurosurgery at municipal general hospital. Bone wax was used to fill the frontal sinus during craniotomy. Thereafter, she developed recurrent abscesses in the right frontal sinus that resolved following surgical removal of the bone wax in the frontal sinus at one year after surgery. Bacteriological examination of the frontal sinus at the time of surgery revealed resistant Pseudomonas aeruginosa. Twenty years after the surgery, the patient once again suffered recurring abscesses due to a right frontal sinus mucocele and underwent radical surgery of the right frontal sinus through a Killian incision, which was performed at the Otolaryngology Department of the same general hospital. An exostomy was performed on the right frontal skin and frontal sinus to prevent repeated abscesses after closure of the nasofrontal canal. However, the right frontal exostosis closed, and frontal sinus abscesses reappeared soon afterwards, as well as downward displacement of the right eyeball due to the mucocele. The patient was referred to another hospital for consultation due to recurrence of a frontal skull base tumor; however, she was hospitalized following acute worsening of the right frontal sinus abscess, which was punctured and drained from a closed fistula in the right frontal region, followed by treatment with antibiotics. Acute exacerbation of frontal sinusitis had occurred approximately three times per year for the past several years. She was then referred to our otolaryngology department for treatment of the right frontal sinus mucocele, which was necessary prior to surgery for recurrence of the anterior skull base tumor. She had a 30-year history of diabetes mellitus, for which she received insulin therapy. One year ago, she had an infarction in the pons and midbrain and was taking bay-aspirin. On initial examination, the right frontal area was not swollen. The skin of the right forehead was strongly depressed. The right eyeball was displaced downward and slightly outward (Figure 1a). The right nasal cavity was difficult to see clearly even with an endoscope because the olfactory cleft was quite narrow. Computed tomography (CT) scan of the paranasal sinuses revealed soft-tissue shadow on the lateral aspect of the right frontal sinus that was suggestive of cyst formation (Figure 1b). Although the cyst was located laterally, an imaging simulation confirmed that it could be opened by removing the upper nasal septum, using curved forceps from the opposite nasal cavity (Figure 2a, b). Surgery was scheduled for two months later, but the cyst became infected two weeks before surgery, with pus exuding from the right frontal sinus fistula. The fistula was punctured and frontal sinus lavage was performed with saline solution. Bacteriological examination revealed Pseudomonas aeruginosa. Two days before surgery, the patient was admitted to the hospital and started on an intravenous infusion of susceptible antibiotics. Surgery was performed under general anesthesia. The left anterior ethmoid sinus, maxillary sinus, and frontal sinus were opened. The nasal septum and perpendicular plate of ethmoid bone were resected superiorly and anteriorly so that both nasal cavities could be seen. The left frontal sinus foramen was drilled while checking the left frontal sinus foramen, and the left agger nasi and nasal bones were also cut open. The mucosa of the nasal septum was pushed down between the nasal septum and the middle nasal meatus to check the first olfactory threads on both sides and confirm the position of the cranial floor. The frontal septum was then scraped open from the left frontal sinus, and the right frontal sinus (specifically, the internal sinus septum cell) was also opened. The cyst on the outer side of the right frontal sinus was punctured with the tip of the seeker through the membranous closure of the cyst, after searching for the location of the cyst with the seeker of the navigation system (Stealth Station S7®, Medtronic, Minneapolis, MA, USA) (Figure 3a). The surrounding frontal bone, including the base of both frontal sinuses with strong bone thickening, was also scraped open to reveal the right frontal sinus mucocele under clear view. The bone around the cyst could not be forceped with a regular curette or other means, including by drilling. Hosemann frontal sinus punches (Karl Storz Slender model, HOSEMANN Frontal Sinus / Recess Punches, 3.5 mm dia. Punch Head, 2.5 mm dia. Sheath, 13 cm Working Length) were inserted through the left nasal cavity and the bone around the right frontal sinus mucocele was cleanly removed and opened (Figure 3b, c). Pus exuding from the inside of the right frontal sinus was repeatedly swabbed. There was no evidence of bone wax inside the frontal sinus. Postoperatively, intranasal Pseudomonas aeruginosa infection occurred that resolved with the administration of antibiotics. At one year after surgery, there is no obstruction of the open mucocele in the right frontal sinus (Figure 4a, b) and no recurrence of inflammation in the right frontal sinus. Long-term follow-up is scheduled to continue.

Figure 1: Initial findings. a) Photograph of the forehead. The external fistula is located in the depression in the right forehead. b) CT coronal section of the sinuses. A frontal sinus mucocele (arrowhead) is seen lateral to an internal septal cell (ISSC) (*) located to the right of the midline.

Figure 2: Preoperative CT image simulation. a, Direction and tip of the frontal sinus punch. b, Simulation of frontal sinus punch using a CT image of the sinuses.