Perioperative lumbar drain utilization in transsphenoidal pituitary resection

Surgical repair technique

The nasoseptal flap was prepared early during the procedure in cases of macroadenomas with suprasellar extension. The surgical cavity was obliterated using fat graft and then Surgicel (ETHICON, New Jersey, USA). Solid floor reconstruction was performed in all cases using Medpor implants (Stryker, Kalamazoo, MI, USA). Next, a layer of TISSEEL (BAXTER, Deerfield, Illinois, USA) was used, and the septal flap was applied followed by nasal packing for 3 days. In cases where leak was not expected but observed, the nasoseptal flap was raised after tumor resection was complete, and the remainder of the floor reconstruction process was performed in a similar manner.

Risk factors

Multiple factors may precipitate a postoperative leak: tumor size, histopathology, redo surgery, intraoperative CSF leak,5 and obesity.11 Macroadenomas are associated with a large intrasellar dead space following tumor resection,12 which aggravates the requirement for surgical reconstruction and increases the risk of postoperative leak.7 In this case series, perioperative LD was inserted in patients with a suprasellar extension as a high-flow leak was expected. Despite the high likelihood of developing a leak in this group, those patients had a lower rate of postoperative CSF leak (1.9%) (Fisher exact test=0.3). This observation may be associated with LD utilization or the lack of correlation between tumor size per se and CSF leak after endoscopic endonasal approaches.13 While observing patients who developed CSF leak in group 2, the majority (6) of cases were female (85%), and all 7 tumors were nonfunctional adenomas. However, in our sample no significance was observed between postoperative leak and tumor size. Histopathologic subtype and other variables in group 2 are listed in Table 5.

Tumor pathology

Histopathological subtype aids in predicting the behavior of pituitary adenomas in terms of invasion of surrounding structures such as CS, optic chiasm, or regrowth after surgery.3 The most common histopathological subtype was non-staining adenoma (23.5%), followed by prolactin-secreting adenoma (14.9%), Follicle Stimulating Hormone-secreting adenoma (12%), and adrenocorticotrophic hormone (ACTH)-secreting adenoma (12%). ACTH-secreting tumors were also associated with higher CSF leak rates;5,14 we found ACTH-secreting adenomas in 2 patients who developed a postoperative leak. In accordance with the literature,3 the majority of tumors were nonfunctional in both groups, with 42 (82.3%) nonfunctional tumors in group 1 and 73 (54%) in group 2 (p<0.001).

CSF leak grading

Intraoperative CSF leaks have been subcategorized by flow type and grade. Petal et al13 proposed that the site and size of the defect determine which vascular tissue flap is utilized in low-flow leaks, while in high-flow leaks reconstruction solely depends on the defect site. In contrast, Esposito et al12 categorized intraoperative CSF leak into 4 grades, where external CSF diversion by LD for 48 hours is reserved for grade 3 CSF leaks combined with surgical repair.12

Complications

Lumbar drain complications are a major concern and cause for decreased utilization of LD. Complications such as pneumocephalus, meningitis, overdrainage, neurological deficit, headache, thromboembolic events caused by activity restriction,15 and catheter disconnection was reported in a study by Ransom et al,8 to be higher than what surgeons recognize in endoscopic skull base cases and may outweigh the risk of postoperative leak. Complication rates for LD were reported as low as 3%,10 and the rate in our study population was similar between the 2 groups (7 [13.7%] and 21 [15.5%] in groups 1 and 2, respectively [p=0.72]). Fortunately, we did not encounter any cases of pneumocephalus or meningitis and did not witness any mechanical complications.

Major and minor complications were encountered in patients sample understudy; a description of cases with these complications follows. Two patients developed nasal bleeding postoperatively that was treated by nasal packing. One patient developed bradycardia that spontaneously resolved and 2 patients suffered from cerebral salt wasting necessitating hospital admission for sodium replacement.

One patient had a headache 8 days postoperatively, and there was no imaging evidence of an intracranial bleed, cerebral edema, or pneumocephalus that could be attributed to LD utilization. Sinusitis was documented in 3 patients for whom 1 extra day of hospital stay was needed for intravenous antibiotics. Two patients had visual loss; in 1 case, an ophthalmic artery aneurysm was detected, and visual loss was attributed to overpacking during surgical repair in the other case in which the patient required reoperation. A narcotic overdose manifested by nausea, vomiting, and pleural effusion occurred in 1 case in which the patient required hospital admission. The same patient was readmitted because of hyponatremia and required sodium replacement. New-onset atrial fibrillation was documented in 1 case; however, the patient did not require hospital admission. Intracranial bleeding occurred in 1 case in which the patient was re-operated on, and asymptomatic subdural hematoma occurred in another patient and the case was conservatively managed.

One patient’s postoperative course was complicated by an asystolic cardiac arrest, which required epinephrine, atropine, and Cardio Pulmonary Resuscitation, for which spontaneous circulation quickly returned. We believe that her macroglossia produced an upper airway obstruction after extubation, resulting in aspiration and subsequent hypoxia, which contributed to her hypoxic asystolic arrest.

Length of hospital stay

A proposed shortcoming of LD utilization is extended length of hospital stay5 in cases where CSF diversion has failed to prevent a leak. When comparing both groups, LD utilization increased the length of hospital stay; mean length of hospital stay was 4.7±1.9 years in group 1 versus 2.7±2.4 years in group 2 (p<0.001), a statistically significant difference.

Nonetheless, when comparing both groups (Table 4), the most common reasons for increased hospital stay in group 1 were headache, nasal bleeding, and CSF leak management. In group 2, the most common reasons to extend hospital stay were treatment of diabetes insipidus, CSF leak, electrolyte abnormalities, and DVT. However, we believe that the benefit of preventing CSF leak while using LD outweighs the hazard of extended length of hospital stay once a leak occurs.

Perioperative LD use in TSS is still controversial. Pepper et al16 compared 2 groups of patients, in which 1 group received LD and the other group did not, and postoperative CSF leak rate was similar in both groups.16 Further, Zhan et al15 reported a higher complication rate in the LD group as well as an improvement in postoperative leak by conservative management with no drain in the control group and proposed that 2–10 days should be the required period for repair material to set in. We note that the best use for perioperative LD is in a highly specific subgroup of patients in whom high-flow leak is predicted and in which the patients have risk factors such as redo surgery, radiotherapy, large tumor size, or previous sinus procedures. Nevertheless, higher sample numbers are necessary for further research and for answering this question.

Limitations

Unfortunately, data regarding intraoperative CSF leak was not graded in this analysis, and data regarding obesity in our patient sample were not collected. This is a limitation of our retrospective review and an area we aspire to address in the future with further research.

In conclusion, LDs are commonly used for perioperative CSF diversion as a prophylactic measure and/or as treatment for CSF rhinorrhea following transsphenoidal pituitary surgery. The complication risk with the use of LDs is low. Although generally considered safe, LD insertion increases the length of hospitalization. Minor complications include headache and patient discomfort. While complications increase health care costs, the presence of LD alone increases resource utilization by adding extra hospital days, laboratory studies, and/or imaging procedures. Thus, LDs should be prudently utilized.