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ORIGINAL ARTICLE
Year : 2023 | Volume
: 71
| Issue : 4 | Page : 678-681
Modified Nasoseptal Flap Technique to Prevent the Recurrence of Rathke's Cleft Cyst
Shejoy P Joshua1, S Shyam Sundar1, Vineeth Viswam2, Dilip Panikar1
1 Department of Neurosurgery, Aster Medcity, Kochi, Kerala, India
2 Department of Otorhinolaryngology, Aster Medcity, Kochi, Kerala, India
Correspondence Address:
Shejoy P Joshua
Consultant, Department of Neurosurgery, Aster Medcity, Kochi, Kerala
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/0028-3886.383837
Background: Rathke's cleft cysts (RCCs) are benign epithelial lesions arising from the Rathke's pouch remnants that fail to regress during embryogenesis. Some RCCs become symptomatic and require treatment. Cyst fenestration and drainage of its contents is the preferred procedure to treat symptomatic cases but carries a risk of recurrence. We propose the use of a novel modified nasoseptal flap technique to partially line the cyst wall to avoid recurrence.
Methods: This was a prospective, observational study that included all RCC patients admitted to the Department of Neurosurgery, Aster Medcity, from April 2015 to May 2018. The modified nasoseptal flap technique was performed in all patients. They underwent preoperative and postoperative ophthalmological, endocrine, endoscopic, and MRI evaluations to look for recurrence.
Results: Ten patients underwent the modified nasoseptal flap technique. The median follow-up was 36 months. Postoperatively, all patients were relieved from headaches. Moreover, their visual fields and pituitary functions normalized. None of the patients developed recurrence of RCC on follow-up brain MRI. On endoscopic examination, all patients had retained patency of the fenestra. The longest follow-up was 72 months.
Conclusions: The modified nasoseptal flap technique maintains patency and avoids recurrence of RCCs on long-term follow-up.
Keywords: Endoscopic fenestration, in vivo stent, nasoseptal flap, Rathke's cleft cyst recurrence
Key Message: Surgical treatment of Rathke's Cleft cyst is marred with high recurrence rate. The modified nasoseptal flap technique is simple, safe and useful in avoiding recurrence over long term follow up.
Rathke's cleft cysts (RCCs) are benign epithelial lesions arising from the Rathke's pouch remnants that fail to regress during embryogenesis. Most of them are asymptomatic and have a reported incidence of 2%–26% among all autopsy cases.[1] However, some RCCs grow in size and cause intermittent headaches or visual or pituitary-hypothalamic dysfunction that mandate surgical decompression. Cyst resection procedures are associated with a higher risk of panhypopituitarism, diabetes insipidus, and CSF leak.[2],[3] Cyst fenestration and drainage of its contents is the preferred procedure but carries a risk of recurrence in 10%–42.9%. This occurs due to the obstruction of the fenestration and recollection of cyst contents from scarring and stenosis.[3],[4],[5] Techniques to maintain patency of the fenestration with stents have been tried with limited success.[6] We modified the nasoseptal flap (NSF) technique in an attempt to avoid restenosis.
The technique and its long-term outcomes have been elucidated.
Objectives
To study the long-term outcome of the modified NSF technique in the surgical management of RCC.
MethodsAfter obtaining institutional ethics committee approval, a prospective, observational study that included consecutive RCC patients managed at the Department of Neurosurgery, Aster Medcity, from April 2015 to May 2018 was conducted (IEC No. AM/EC/206-2021).
Surgical indications included persistent headache, visual impairment, or progressive endocrine dysfunction. Inability to use this technique due to lack of mucosal flap from a previous surgery/radiation or intraoperative CSF leak constituted the exclusion criteria.
All patients underwent preoperative visual acuity and field assessment by an ophthalmologist, endoscopic examination by an otolaryngologist, and endocrinological evaluations. Adrenocorticotropic hormone (ACTH), growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), thyroxine, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and morning cortisol levels were tested. The normal ranges of these hormones were defined based on normal reference ranges from the Department of Laboratory Medicine in our institution. Hypoadrenalism was defined as the patient having low morning cortisol level (<3 μg/dl). Low insulin growth factor 1 (IGF-1) level was defined according standard deviation from the normal levels for each age and sex. Hyperprolactinemia was defined as an elevated PRL level (>25 ng/ml). Hypothyroidism was defined as a low free thyroxin level (<0.8 ng/dl) with a low or normal TSH level (0.5–5 μIU/ml). Diabetes insipidus was defined clinically and/or according to the need for desmopressin therapy.
Surgical complications, such as CSF leak, meningitis, and sinusitis, were noted. Histological examination of the excised cyst wall was performed by a neuropathologist. Postoperatively, clinical, endocrinological, and radiological follow-ups were performed at two weeks, three months, and every year thereafter. Ophthalmological testing was performed at one month and one year after surgery in cases of preoperative visual dysfunction, and testing was stopped after normalization of visual acuity and visual field. New onset endocrine dysfunction, according to clinical and laboratory assessment, was defined as permanent when found to persist for over a year.
Surgical technique [Video 1]
All patients underwent endoscopic and endonasal approach in collaboration with an otorhinolaryngologist. The NSF was raised pedicled on the septal branch of the sphenopalatine artery, as described by Hadad et al.[7] The tip of the flap was cut and fashioned into two small leaflets, each measuring 3–4 mm in width and 5–7 mm in length [Figure 1]. Next, the sellar floor was drilled to expose the dura. After confirming the location of the cyst using navigation (Medtronics Stealth, Minneapolis, USA), we made a dural opening in an inverted U shape while ensuring no CSF leak occurred. The anterior wall of the RCC was fenestrated and its contents evacuated. The resected cyst wall was sent for histopathological examination [Figure 2].
Figure 1: Distal end of the nasoseptal flap modified/fashioned into two leaflets by sharply cutting it with scissors
Figure 2: Anterior wall of the Rathke's cleft cyst resected using scissors to create a wide fenestrationOne of the leaflets of the NSF was then placed within the cavity and the other leaflet was placed on the surrounding bone. The leaflet within the RCC avoided stenosis. The outer leaflet stabilized the flap and initiated epithelialization [Figure 3].
Figure 3: Modified nasoseptal flap being used to line a wall of the Rathke's cleft cyst and the other leaflet placed over the sellar boneThe RCC cavity was left open to drain via this modified opening. The stem of the flap was supported using small cut pieces of a NASASTENT (Smith & Nephew Inc, Austin, TX).
It is important to avoid a CSF leak; if such a leak occurred, it would have warranted sellar reconstruction with a complete NSF that precluded the usage of the modified flap technique, as explained here.
Otolaryngologist follow-up
All patients underwent post operative endoscopic examinations by the otolaryngologist at 3 months and 1 year. The persistent communication between the RCC and sphenoid sinus was defined as patent fenestration.
ResultsTen patients underwent the modified NSF technique during the study period; of the ten, seven were men and three were women. The mean age was 34 (range: 9–54) years. The median follow-up was 36 (range: 3–80) months. Headache was the initial presentation in 70% of patients. Sixty percent of patients were found to have field deficits that were mostly bilateral, superior, temporal quadrantanopia on preoperative visual field examination. On hormonal evaluation, 70% of patients were found to have pituitary hypofunction preoperatively. Seventy percent of patients had suprasellar extension on preoperative MRI brain [Figure 5]a. None of the patients developed intraoperative CSF leak. Four patients developed transient diabetes insipidus that recovered on follow-up. None of the patients developed permanent postoperative diabetes insipidus or any other pituitary dysfunction during the follow-up.
Postoperatively, there was relief from headache, and visual fields and pituitary functions normalized in all patients. Follow-up MRI showed uptake of the NSF, and none of the patients developed recurrence of RCC [Figure 5]b and [Figure 5]c. On conducting follow-up endoscopic examinations, we found that all patients had patent fenestra. The longest follow-up was 72 months postoperatively [Figure 4]a and [Figure 4]b. The findings are summarized in [Table 1].
Figure 4: Endoscopic view of patent fenestration (a) at 3 months and (b) at 72 months, both postoperatively. Note the complete mucosalization of the edges of the fenestration
Figure 5: T1-weighted contrast MRI. (a) Preoperative, showing sellar-suprasellar RCC; (b) 3 months postoperatively, showing enhancing nasoseptal flap and absence of the RCC; (c) 12 months postoperatively, showing absence of RCC
Table 1: Pre- and postoperative evaluation and outcome of the modified nasoseptal flap Discussion Small, asymptomatic, fluid-filled RCCs are found in up to 26% of autopsy series.[1] Rarely, these RCCs enlarge and become symptomatic. The usual clinical presentation is a triad of headache, visual impairment, and pituitary dysfunction, all in varying combinations. When RCCs become symptomatic, surgical intervention is indicated. The current standard is an endoscopic, endonasal, transsphenoidal approach.[8],[9]
Gross total resection of the RCC wall was associated with increased risk of postoperative complications, particularly complications like endocrinopathies and CSF leakage when compared with fenestration and cyst decompression. Complete cyst excision is, hence, less favored than fenestration.[4],[10],[11],[12] However, fenestration has been associated with a higher recurrence rate from scarring, occlusion of the fenestration, and re-accumulation of cyst contents.[5]
Measures to avoid stenosis have been explored. Silicone and steroid-eluting stents have been used for maintaining cyst drainage.[13],[14] However, these foreign objects run the risk of causing bacterial infections, foreign body reactions, or potential rejection, and little is known of their long-term outcomes.
NSF, as described by Hadad et al.,[7] is used extensively in endoscopic reconstructive surgery.[7] Karligkiotis et al.[15] used the pedicled NSF to treat cholesterol granulomas of the petrous apex and to avoid its recurrence. They found that this technique conferred long-term patency of the cyst cavity. The surgical technique we described in this paper has been shown to maintain patency of the fenestration and avoid cyst recurrence. The modified NSF adheres to the surrounding bony edges, ensures rapid epithelialization of the fenestra, and prevents its closure by acting as an in vivo stent. This allows infrasellar drainage pathway for the cyst contents. Kuan et al.[16] described lining the entire interior of the cyst wall with the NSF. They found that this was useful in shorter follow up upto 29 months. Our technique, requires a smaller NSF to line only the anterior third of the cyst wall, which would result in lesser nasal morbidity. This modification makes the technique easier to use and shortens operative time. This technique has proved to be effective in preventing recurrence of RCC in the long-term, that is, to 72 months.
A limitation of this study is the small number of patients. However, the absence of recurrence on long-term follow-up proves that this is a versatile technique to prevent recurrence.
ConclusionThe novel modified NSF technique allows for the re-epithelialization of the fenestra, prevents restenosis and recurrence of RCC, acts as an in vivo stent, and retains patency over a long-term follow-up of up to six years with no added surgical morbidity.
Financial support and sponsorship
This work was supported by the Institutional Intramural Research Fund from the Aster DM Health Foundation (grant numbers IMRS 002).
Conflicts of interest
There are no conflicts of interest.
References
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