Patrick Realon

Posted Date

Mar 31, 2022, 8:25 AM

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Postoperative cerebrospinal fluid (CSF) leak is a well-known complication following transsphenoidal surgery for sellar lesions, with a reported incidence in the range of 8.6%–15.9%. Its occurrence may result in meningitis, and prolonged treatment or reparative surgery are required in some patients. Following transsphenoidal surgery, patients are at risk for developing a variety of neuroendocrine or other postoperative complications, which can potentially be minimized or prevented by maintaining a high degree of awareness for such issues on the part of the neurosurgical team and nursing staff. Serial clinical monitoring of a patient's neurological and visual status is imperative following transsphenoidal surgery, as patients may develop untoward complications such as postoperative hematomas, epistaxis, ischemic events, hydrocephalus, CSF leaks, or meningitis. Maintaining a constant state of vigilance for these uncommon, but serious, events in all patients is absolutely critical. If a CSF leak is suspected in the postoperative period, a noncontrast CT scan of the head is a useful study that may demonstrate the presence of intracranial air in the event of a CSF leak. Although the majority of patients do not require insertion of nasal packing at the time of surgery, some patients (especially those with or intraoperative CSF leaks requiring sellar floor reconstruction, Cushing's Disease, and acromegaly) may benefit from their insertion. If used, nasal packing can typically be removed on postoperative day one. Postoperative epistaxis infrequently develops following transsphenoidal surgery and can typically be treated successfully with routine nasal packing for 2-3 days. In rare refractory cases of epistaxis, reoperation or endovascular embolization of an arterial bleeder may be required (Sun et al., 2018). 

Aberrancies of fluid homeostasis and serum electrolytes occur quite commonly following transsphenoidal surgery. An understanding of the underlying physiology, coupled with monitoring of a patient's volume status, as well as serum and urine laboratory studies, may make a significant difference in a patient's postoperative course. Although a foley catheter is not inserted at the time of surgery in the majority of patients at our institution, strict measurement of a patient's intake, output, and daily weight should be carried out in order to provide a continuous assessment of volume status.  Patients with preoperative evidence of hypopituitarism should be maintained on sufficient stress doses of hormonal replacement during the initial perioperative period, and then kept on physiological maintenance doses of replacement agents until it is appropriate to assess their pituitary function in a controlled manner. Patients with evidence of hormonal excess typically undergo appropriate lab testing during the first few days following surgery to assess for evidence of early endocrinological remission (Sun et al., 2018).

Primary reconstruction techniques use autologous grafts (e.g., fascia lata) or a pedicled nasoseptal flap to reconstruct the skull base when a CSF leak occurs during or after surgery. However, due to the unpopularity of endoscopy and unfamiliarity with this reconstruction method in surgery department, we used alternative repair methods and also obtained excellent results. Most patients chose conservative methods for CSF rhinorrhoea repair, with surgical repair used only if conservative treatment failed. Our strategies often eliminated the need for additional surgery; however, conservative treatment may increase the risk of infection, duration of hospitalization and economic and psychological burden on the patient. Surgical repair should be performed as soon as general clinical conditions allow if diagnostic assessments have detected CSF rhinorrhoea and identified the exact site of the leak. They concluded that clinical presentation and office-based endoscopic nasal exam were of primary importance to evaluate suspected CSF leaks. Prospective randomised controlled studies are needed to clarify the optimal approach and time window for surgical repair of CSF rhinorrhoea (Zhang et al., 2017).

Endoscopic endonasal pituitary surgery differs from the transsphenoidal microsurgery in the following aspects: plane vision, close-up view, no nasal speculum, endonasal approach and ample vision field. Microscopy features a three-dimensional visualisation, wider view and use of a transnasal speculum. Use of the endoscope during TSS is important in that it allows maximum tumoural excision and better visualisation of a small CSF fistula. Because of the enhanced illumination and visualisation of lesions, endoscopic surgery for CSF rhinorrhoea is more reliable and convenient than traditional TSS. In addition, we found that the endoscopic approach enables precise confirmation of the leakage site, sufficient exposure, minimal invasiveness and high rate of success. Although endoscopy was underutilised initially in our department, we subsequently used endoscopy to repair CSF leakage with excellent results. We therefore strongly recommend endoscopy for surgical repair as well as tumour removal (Zhang et al., 2017).

Following discharge, patients are usually seen in the clinic for routine follow-up one week after surgery, then again at the 6-week postoperative time point for routine endocrine and postoperative evaluation, to account for equilibration of the hypothalamic-pituitary-adrenal axis as well as the longer half-life of thyroid hormone. Postoperative MR imaging is obtained 3 months following the operation, to allow sufficient resolution of postoperative changes prior to any meaningful assessment regarding the extent of tumor resection. Routine imaging studies may then be obtained annually, or more often as indicated. Patients with sellar pathology may have delayed tumor recurrences occurring up to several years after successful remission, therefore mandating continued endocrinological and imaging surveillance, even beyond a decade following initial remission (Sun et al., 2018).

References:

Sun, I., Lim, J. X., Goh, C. P., Low, S. W., Kirollos, R. W., Tan, C. S., Lwin, S., & Yeo, T. T. (2018). Body mass index and the risk of postoperative cerebrospinal fluid leak following transsphenoidal surgery in an asian population. Singapore medical journal, 59(5), 257–263. https://doi.org/10.11622/smedj.2016159

Zhang, C., Ding, X., Lu, Y., Hu, L., & Hu, G. (2017). Cerebrospinal fluid rhinorrhoea following transsphenoidal surgery for pituitary adenoma: Experience in a Chinese centre. Rinoliquorrea dopo chirurgia dell’adenoma ipofisario con approccio transfenoidale: esperienza in un centro cinese. Acta otorhinolaryngologica Italica : organo ufficiale della Societa italiana di otorinolaringologia e chirurgia cervico-facciale, 37(4), 303–307. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5584102/