PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery 2322 PhiliPPine Journal of otolaryngology-head and neck Surgery PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 ORIGINAL ARTICLES ABSTRACT Objective: To determine the incidence of cerebrospinal fluid (CSF) leak after Hadad- Bassagasteguy Flap (HBF) reconstruction after endoscopic endonasal transsphenoidal surgery for skull base pathologies from 2016 to 2020 at the University of the East Ramon Magsaysay Memorial Medical Center. Methods: Design: Case Series Setting: Tertiary Private Training Hospital Participants: Charts of 35 patients who underwent endoscopic endonasal transsphenoidal surgery with reconstruction using Hadad-Bassagasteguy flap between January 2016 to February 2020 were reviewed and data on demographics, date of procedure, mass size, final diagnosis, presence of preoperative, intraoperative and postoperative CSF leak, placement of lumbar drain and course in the wards were collected. Results: There were 23 women and 12 men with ages ranging from 21 to 71 years. Four patients (11.4%) had postoperative CSF leak after reconstruction with HBF. Two of these four patients had episodes of nose blowing and sneezing weeks after surgery, prior to the development of the CSF leak. The other two patients experienced CSF leak 3 days postoperatively. Conclusion: HBF has been a workhorse for reconstruction of skull base defects after transsphenoidal surgery, and based on our experience remains to be so, making it possible for expanded approaches and a wide variety of pathologies to be operated on via the endonasal route. Keywords: Hadad-Bassagasteguy flap, Hadad flap, cerebrospinal fluid leak; CSF leak, Endoscopic endonasal transsphenoidal surgery Cerebro-Spinal Fluid Leak in Skull Base Reconstruction Using Hadad - Bassagasteguy Flap after Endoscopic Endonasal Transsphenoidal Surgery: A Case Series Jan Paul D. Formalejo, MD Jay Pee M. Amable, MD Department of Otorhinolaryngology Head and Neck Surgery University of the East Ramon Magsaysay Memorial Medical Center Correspondence: Dr. Jay Pee M. Amable Department of Otorhinolaryngology Head and Neck Surgery University of the East Ramon Magsaysay Memorial Medical Center 5th Floor, ENT Office, Hospital Service Bldg., 64 Aurora Blvd., Quezon City 1113 Philippines Phone: (632) 8715 0861 local 257 Telefax: (632) 8716 1789 E-mail: jpamablemd@gmail.com The authors declared that this represents original material that is not being considered for publication or has not been published or accepted for publication elsewhere, in full or in part, in print or electronic media; that the manuscript has been read and approved by all the authors, that the requirements for authorship have been met by the authors, and that each author believes that the manuscript represents honest work. Disclosure: The authors signed disclosures that there are no financial or other (including personal) relationships, intellectual passion, political or religious beliefs, and institutional affiliations that might lead to a conflict of interest. Presented at the Philippine Society of Otolaryngology Head and Neck Surgery, 1st Virtual Descriptive Research Contest (3rd Place) October 21, 2020. Philipp J Otolaryngol Head Neck Surg 2021; 36 (2): 22-24 c Philippine Society of Otolaryngology – Head and Neck Surgery, Inc. Creative Commons (CC BY-NC-ND 4.0) Attribution - NonCommercial - NoDerivatives 4.0 International PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery 2322 PhiliPPine Journal of otolaryngology-head and neck Surgery PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 ORIGINAL ARTICLES The transsphenoidal route is the standard approach for pituitary or sellar tumors of the skull base.1 Endoscopic endonasal transsphenoidal surgery (EETS) is a minimally invasive technique that is the current approach of choice for pituitary and sellar tumors.2,3 Expanded endonasal approaches have been developed, making it possible to access the skull base through the nasal cavity, enabling access to the suprasellar, parasellar and retrosellar spaces.4 However, cerebrospinal fluid (CSF) leak has been one of the feared complications of endoscopic endonasal transsphenoidal surgery. Hadad et al.5 described the Hadad-Bassagasteguy Flap (HBF) to reconstruct skull base defects after endoscopic endonasal expanded approaches. It utilizes a neurovascular pedicle flap of the nasal septum mucoperiosteum and mucoperichondrium based on the nasoseptal artery, a branch of the posterior septal artery and the terminal branches of the internal maxillary artery.5 This technique has reduced the incidence of cerebrospinal fluid leak after expanded endonasal approaches from >20% to 4-6%. 2,5-7 A number of studies have been published in the success of their EETS using HBF.2,5-7 However, after a search of HERDIN Plus, the ASEAN Citation Index (ACI), WHO Global Index Medicus - Western Pacific Region Index Medicus (WPRIM), Directory of Open Access Journals (DOAJ), PubMed (MEDLINE and PubMed Central), and the Cochrane Database, we found no local published data regarding its utilization and surgical outcomes in the Philippines. This study aims to determine the incidence of cerebrospinal fluid leak after HBF reconstruction after endoscopic endonasal transsphenoidal surgery for skull base pathologies from 2016 to 2020 at the University of the East Ramon Magsaysay Memorial Medical Center. METHODS With University of the East Ramon Magsaysay Memorial Medical Center Research Institute for the Health Sciences Ethics Review Committee approval (RIHS ERC Code: 0865/H/2020/093), hospital records of all adult patients who underwent EETS with reconstruction using HBF between January 2016 and February 2020 were considered for inclusion in this case series. Charts with incomplete data were subsequently excluded. The surgical technique for the harvest of the HBF followed the technique of Hadad et al.5. We utilized a multilayer technique with the use of abdominal fat graft, septal cartilage graft, HBF, Monomeric N-butyl-2-cyanoacrylate glue and a bioresorbable nasal dressing. Medical records were individually reviewed, and the patient’s age, sex, date of procedure, size of mass, final diagnosis, presence of preoperative, intraoperative and postoperative CSF leak, placement of lumbar drain after EETS and course in the wards were recorded by the first author in a data collection form. The presence of intraoperative CSF leak was determined based on the intraoperative findings in the operative technique. The occurrence of postoperative CSF leak was determined based on the course in the wards of each patient, daily physical examination record, and nasal endoscopy reports in the charts. Descriptive statistical evaluation was performed using Microsoft Excel 2019 Version 16.52 (Microsoft Corp., Redmond WA, USA) and data was presented using percentages, means and standard deviations. RESULTS A total of 35 hospital records were included in this series. They represented 23 women and 12 men with ages ranging from 21 to 71 years old (mean, 47 years). The different pathologies were 28 (80%) pituitary macroadenomas, two (5.7%) craniopharyngiomas, two (5.7%) squamous cell carcinomas, and 1 each (2.8% each) pituitary cyst, chordoma, and idiopathic CSF leak. Depending on pathology, the different surgical approaches used were two transplanar, two transclival, and 31 transsellar. Four (11.4%) of the 35 patients had postoperative cerebrospinal fluid leak. The first patient had CSF leak 1 week after surgery after the patient purposely blew his nose and sneezed despite strict instructions to refrain from such actions. The second patient had CSF leak at home 2 weeks postoperatively, also after intentional nose blowing and frequent sneezing. He had been ambulatory on discharge and was able to maintain upright position and flex his head anteriorly without CSF rhinorrhea. The third and fourth patients developed CSF leak 3 days after surgery with no identified aggravating cause. Eleven (31.4%) patients did not have a postoperative lumbar drain, which were the ones with no gross intraoperative CSF leak during EETS. All patients who had a postoperative lumbar drain (68.6%) had an intraoperative CSF leak. The 4 patients who had postoperative CSF leak had a postoperative lumbar drain placed after the EETS. Among the patients who experienced post-operative CSF leak, three were diagnosed with pituitary macroadenoma and one was diagnosed with craniopharyngioma. In terms of size, the mean diameter of the mass among the patients was 3.1 ± 1.28 centimeters. The four patients who experienced post-operative CSF leak had a mass diameter ranging from 2.5 to 3.8cms. Postoperative CSF leak of the three patients resolved by repositioning of the previously laden HBF. The postoperative CSF leak of the fourth patient was resolved by utilizing a lateral nasal mucosal wall flap to reconstruct the defect. All the CSF leaks were identified at the lateral and superior edges of the HBF. No recurrence of CSF leak was noted after the repair in all 4 patients. PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery 2524 PhiliPPine Journal of otolaryngology-head and neck Surgery PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 PhiliPPine Journal of otolaryngology-head and neck Surgery Vol. 36 no. 2 July – december 2021 ORIGINAL ARTICLES DISCUSSION In our study 11.4% of patients had a postoperative CSF leak which is higher than rates reported internationally. It is of note that of the four patients who had CSF leak, two had an aggravating cause - purposeful nose blowing and sneezing with most of the force passing through the nasal cavity instead of releasing it through the mouth. It is also noteworthy that the postoperative CSF leak in the two patients occurred only after the incident of nose blowing. Blowing through the nose and sneezing may lead to increased intracranial pressure, which in turn, may cause a CSF leak.8 Furthermore, these actions may displace the HBF, thereby causing CSF rhinorrhea. Carabba et al.9 showed that the incidence of CSF leak after expanded endonasal approach without the HBF was 24%.9 Since the advent of HBF, reports have shown a decrease in postoperative CSF leak after expanded endonasal approaches to 4-6%.2,5-7 If we exclude the two patients who had an external aggravating cause, the rate of spontaneous post-operative CSF leak would then be 5.7%, which is within the range of reported complication rates of other published studies.2,5-7 To the best of our knowledge, there are no other reports in the Philippines that provide an incidence of postoperative CSF leak after reconstruction using HBF. There are various reasons why CSF leak can occur postoperatively even with reconstruction and these are: 1) Insufficient size of the flap, 2) Tucking of flap margins, 3) Reverse placement of the flap, 4) Pedicle constriction which leads to flap ischemia, 5) Incomplete denudation of the bony margin of the reconstructed defect, 6) Flap retraction, and 7) Ineffective arrangement of the multilayer reconstruction.10,11 In our case, the most likely cause for the other 2 patients who did not have any aggravating cause is incomplete denudation of the bony margin of the reconstructed defect. The CSF leak was noted to occur at the edges of the HBF where the incomplete denudation of the bony margin may have occurred. There are numerous limitations in this study. The study sample size is small with only 35 patients. Due to the small sample size, no inferential statistical analysis could be done to assess for associations between age, pathology of the mass, size of the mass, presence of intraoperative CSF leak and presence of lumbar drain. Also, the small sample size may not be representative of the population. The study also lacks a control group. This study is a retrospective study and was based on chart review. A prospective study would be better to evaluate the associations between other factors that may lead to CSF leak. Indeed, the HBF has become a workhorse for reconstruction of skull base defects after transsphenoidal surgery, and based on our experience remains to be so, making it possible for expanded approaches and a wide variety of pathologies to be operated on via the endonasal route. ACKNOWLEDGEMENTS We would like to acknowledge the UERMMMCI Neurosurgery Department headed by Dr. Alfredo L. Tan and Dr. Christopher O. Concepcion for the surgical collaboration and Dr. Joey Francis B. Hernandez for his statistical assistance. REFERENCES 1. de Divitiis E, Cappabianca P, editors. Endoscopic endonasal transsphenoidal surgery. 1st ed. New York: Springer; 2003. 2. Brunworth J, Lin T, Keschner DB, Garg R, Lee JT. Use of the Hadad-Bassagasteguy flap for repair of recurrent cerebrospinal fluid leak after prior transsphenoidal surgery. Allergy Rhinol (Providence). 2013 Fall;4(3):e155-61. DOI: 10.2500/ar.2013.4.0072; PubMed PMID: 24498521; PubMed Central PMCID: PMC3911805. 3. Cappabianca P, Cavallo LM, de Divitiis E. Endoscopic endonasal transsphenoidal surgery. Neurosurgery. 2004 Oct;55(4):933-40; discussion 940-1. DOI: 10.1227/01. neu.0000137330.02549.0d; PubMed PMID: 15458602. 4. Chung YG. Advances and technical standards in neurosurgery (Volume 33). J Korean Neurosurg Soc. 2008 Feb; 143(2): 123. DOI: https://doi.org/10.3340/jkns.2008.43.2.123. 5. Hadad G, Bassagasteguy L, Carrau RL, Mataza JC, Kassam A, Snyderman CH, et al. A novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope. 2006 Oct;116(10):1882-6. DOI: 10.1097/01. mlg.0000234933.37779.e4; PubMed PMID: 17003708. 6. Kassam AB, Thomas A, Carrau RL, Snyderman CH, Vescan A, Prevedello D, et al. Endoscopic reconstruction of the cranial base using a pedicled nasoseptal flap. Neurosurgery. 2008 Jul;63(1 Suppl 1):ONS44-52; discussion ONS52-3. DOI: 10.1227/01.neu.0000297074.13423.f5; PubMed PMID: 18728603. 7. Singh CV, Shah NJ. Hadad-Bassagasteguy flap in reconstruction of skull base defects after endonasal skull base surgery. Int J Otorhinol Head Neck Surg. 2017;3(4):1020. DOI:10.18203/ issn.2454-5929.ijohns20174325. 8. Deenadayal DS, Vidyasagar D, Naveen Kumar M, Sudhakshin P, Sharath Chandra SV, Hameed S. Spontaneous CSF rhinorrhea: our experience. Indian J Otolaryngol Head Neck Surg. 2013 Aug; 65(Suppl 2): 271–275. 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