Although rates of postoperative morbidity and mortality have become relatively low in patients undergoing transnasal transsphenoidal surgery (TSS) for pituitary adenoma, cerebrospinal fluid fistulas remain a major driver of postoperative morbidity. Persistent CSF fistulas harbor the potential for headache and meningitis.
Staartjes et al., trained and internally validated a robust deep neural network-based prediction model that identifies patients at high risk for intraoperative CSF. Machine learning algorithms may predict outcomes and adverse events that were previously nearly unpredictable, thus enabling safer and improved patient care and better patient counseling 1).
The objective of a study of Umamaheswaran et al., was to assess the incidence of CSF leak following pituitary surgery and the methods of effective skull base repair. This retrospective observational study conducted in a tertiary care hospital after obtaining due clearance from the Institutional ethics committee. The charts of patients who underwent endonasal pituitary surgery between 2013 and 2018 were studied and details noted. Patients undergoing revision surgery or with history of preoperative radiotherapy were excluded from the study. 52 patients were included in the study. Based on the type of CSF leak, the patients were grouped into four. 19 patients (36.5%) had an intraoperative CSF leak. 3 patients developed a postoperative CSF leak. Based on the histopathology, 4 patients had ACTH secreting tumor. 8 patients had growth hormone secreting tumor, 22 had gonadotropin secreting tumor, 9 patients had a non-functioning tumour and 9 patients had prolactinoma. The type of skull base repair performed in these patients were grouped into 4.18 patients underwent type I repair, 21 patients underwent type II repair, 8 patients underwent type III repair and 5 patients underwent type IV repair. They observed that the pedicled nasoseptal flap is particularly advantageous over other repair techniques, especially in low pressure leaks. The strategy for skull base repair should be tailored to suit each patient to minimise the occurrence of morbidity and the duration of hospital stay 2).
Dural suturing technique may supply a rescue method. However, suturing and knotting in such a deep and narrow space are difficult. Training in the model can improve skills and setting a stepwise curriculum can increase trainers' interest and confidence.
METHODS: We constructed an easy model using silicone and acrylic as sphenoid sinus and using the egg-shell membrane as skull base dura. The training is divided into three steps: Step 1: extracorporeal knot-tying suture on the silicone of sphenoid sinus, Step 2: intra-nasal knot-tying suture on the same silicone, and Step 3: intra-nasal egg-shell membrane knot-tying suture. Fifteen experienced microneurosurgical neurosurgeons (Group A) and ten inexperienced PGY residents (Group B) were recruited to perform the tasks. Performance measures were time, suturing and knotting errors, and needle and thread manipulations. The third step was assessed through the injection of full water into the other side of the egg to verify the watertight suture. The results were compared between two groups.
RESULTS: Group A finishes the first and second tasks in significantly less time (total time, 125.1 ± 10.8 vs 195.8 ± 15.9 min) and fewer error points (2.4 ± 1.3 vs 5.3 ± 1.0) than group B. There are five trainers in group A who passed the third step, this number in group B was only one.
CONCLUSIONS: This low cost and stepwise training model improved the suture and knot skills for skull base repair during endoscopic endonasal surgery. Experienced microneurosurgical neurosurgeons perform this technique more competent 3).