Delayed postoperative hyponatremia after endoscopic transsphenoidal surgery for pituitary adenoma

Urinary oxytocin secretion after pituitary surgery, early arginine vasopressin deficiency and syndrome of inappropriate antidiuresis

PURPOSE

Transient arginine vasopressin deficiency (AVP-D), previously called diabetes insipidus, is a well-known complication of transsphenoidal pituitary surgery (TPS) with no definite predictive biomarker to date making it difficult to anticipate. While oxytocin (OXT) was previously suggested as a possible biomarker to predict syndrome of inappropriate diuresis (SIAD)-related hyponatraemia after TPS, its secretion in patients presenting with AVP-D remains poorly understood. We therefore hypothesized that OXT might present a different secretion in the case of AVP-D which would support its potential as an early biomarker of AVP-D. Moreover, we hypothesized that abnormal secretion of OXT might occur later on, notably with SIAD.

METHODS

We measured the urinary output of OXT in 67 consecutive patients subjected to TPS and compared the values of oxytocin between time-points and OXT ratio between groups. The primary endpoint of our study was to identify a difference in urinary OXT excretion in patients suffering from AVP-D compared to patients remaining normonatraemic. As a secondary endpoint, we compared the evolution of OXT secretion after the diagnosis of AVP-D in both groups, comparing the patients that later developed SIAD with the ones that did not.

RESULTS

Patients developing AVP-D showed a delay in the increase of OXT secretion after TPS as shown by a significantly lower ratio of OXT between the first postoperative day and the day of surgery (0.88 VS 1.68, p = 0.0162, IC:0.2979-0.2642) but a significantly higher ratio of OXT between the fourth and the first postoperative days (1.17 VS 0.53, p = 0.0006, IC:-2.109-0.6092). Moreover, normonatraemic patients that did not show normalization of OXT levels at day 4 after surgery tended to develop SIAD later on.

CONCLUSION

Taken together, these results show for the first time that OXT release might help predict AVP-D after TPS and differentiate it from other pathologies of water-sodium balance.

A Simple Scoring System for Predicting the Risk of Delayed Hyponatremia After Endoscopic Transsphenoidal Surgery for Pituitary Adenomas

BACKGROUND

To identify high-risk patients for delayed postoperative hyponatremia (DPH) early, we constructed a simple and effective scoring system.

METHODS

We retrospectively analyzed 141 consecutive patients who underwent endoscopic transsphenoidal surgery from January 2019 to December 2022. Patients were divided into DPH group and nondelayed postoperative hyponatremia group based on whether hyponatremia occurred after the third postoperative day. Multivariable logistic regression analysis was conducted to determine the predictive factors of DPH, and a simple scoring system was constructed based on these predictors.

RESULTS

Among 141 patients, 36 (25.5%) developed DPH. Multivariable logistic regression analysis showed that age ≥48 years (odds ratio [OR], 3.74; 95% confidence interval [CI], 1.14-12.21; P = 0.029), Knosp grade ≥3 (OR, 5.17; 95% CI, 1.20-22.27; P = 0.027), postoperative hypokalemia within three days (OR, 3.13; 95% CI, 1.05-9.33; P = 0.040), a difference in blood sodium levels between the first and second day after surgery ≥1 mEq/L (OR, 3.65; 95% CI, 1.05-12.77; P = 0.043), and postoperative diabetes insipidus (OR, 3.57; 95% CI, 1.16-10.96; P = 0.026) were independent predictors of DPH.

CONCLUSIONS

This scoring system for predicting DPH has an area under the receiver operating characteristic curve of 0.856 (95% CI, 0.787-0.925), indicating moderate to good predictive value for DPH in our cohort, but further prospective external validation is needed.

Gender potentially affects early postoperative hyponatremia in pituitary adenoma: XGBoost-based predictive modeling

Purpose

The occurrence of hyponatremia is a prevalent complication following transnasal transsphenoidal surgery for pituitary adenoma surgery, which adversely affects patient prognosis, hospitalization duration, and rehospitalization risk. The primary objective of this study is to strengthen the correlation between clinical factors associated with pituitary adenoma and postoperative hyponatremia. Additionally, the study aims to develop a predictive model for postoperative hyponatremia in patients with pituitary adenoma, with the ultimate goal of establishing a basis for reducing the occurrence of postoperative hyponatremia following surgical interventions.

Methods

The chi-square test or Fisher test was employed for nominal data, while the t-test or Mann-Whitney test was utilized for continuous data analysis. In cases where the data exhibited statistical differences, binary logistic analysis was conducted to examine the risk and protective factors associated with postoperative hyponatremia. XGBoost was employed to construct predictive models for hyponatremia in this study. The patients were partitioned into training and test sets, and the most suitable parameters were determined through five-fold cross-validation and subsequently utilized for training on the training set. The discriminatory capability was assessed on the internal validation set.

Results and conclusions

Out of the total 280 patients included in this investigation, 82 patients experienced early postoperative hyponatremia. Among these individuals, male gender (P = 0.02, odds ratio = 1.98) was identified as a risk factor for early postoperative hyponatremia, while preoperative chloride levels (P = 0.021, odds ratio = 0.866) and surgery time (P = 0.039, odds ratio = 0.990) were identified as protective factors against postoperative hyponatremia. The XGBoost model exhibited a sensitivity of 94.2%, a specificity of 61.5%, a positive predictive value of 51.6%, a negative predictive value of 96%, and identified male gender, preoperative sodium, and preoperative cortisol as the most significant predictors. Our findings indicate that gender may have influence in the development of early postoperative hyponatremia in patients with pituitary adenomas.

Incidence of postoperative hyponatremia after endoscopic endonasal pituitary transposition for skull base pathologies

PURPOSE

Pituitary transposition is a novel surgical approach to access the retroinfundibular space and interpeduncular cistern. Few studies have evaluated post-surgical outcomes, including incidence of hyponatremia, following pituitary transposition.

METHODS

This is a retrospective study including 72 patients who underwent endoscopic endonasal surgery involving pituitary transposition for non-pituitary derived tumors over a decade at the University of Pittsburgh Medical Center. Anterior pituitary deficiencies and replacement therapy, tumor pathology and pre-operative serum sodium (Na) were recorded. Na was assessed at postoperative day 1, 3, 5, 7, and 10. Anatomical/surgical parameters included sellar height, sellar access angle to approach the tumor, and cranial extension of the tumor above the sellar floor (B) compared to the height of the gland (A) (B/A). T-test (normally distributed variables) and Wilcoxon rank-sum test (not-normally distributed) were applied for mean comparison. Logistic regression analyzed correlations between anatomical/surgical parameters and postoperative hyponatremia.

RESULTS

55.6% of patients developed post-operative transient hyponatremia. Two patients (5%) developed severe hyponatremia (sodium level < 120 mmol/L). Eleven (15.3%) patients required desmopressin replacement immediately post-operatively, and 2 other patients needed desmopressin after discharge and after sodium nadir developed. Hyponatremia was inversely associated with sellar access angle (p = 0.02) and the tumor cranial extension above the sellar floor showing a trend towards significance (p = 0.09).

CONCLUSION

More than half of patients who had pituitary transposition developed transient hyponatremia. Hyponatremia was more common in those with narrower sellar access angle and smaller cranial extension of the tumor above the sellar floor. Anatomical/surgical parameters may allow risk-stratification for post-operative hyponatremia following pituitary transposition.

Preoperative Serum Copeptin Can Predict Delayed Hyponatremia after Pituitary Surgery in the Absence of Arginine Vasopressin Deficiency

BACKGRUOUND

Delayed postoperative hyponatremia (DPH) is the most common cause of readmission after pituitary surgery. In this study, we aimed to evaluate the cutoff values of serum copeptin and determine the optimal timing for copeptin measurement for the prediction of the occurrence of DPH in patients who undergo endoscopic transsphenoidal approach (eTSA) surgery and tumor resection.

METHODS

This was a prospective observational study of 73 patients who underwent eTSA surgery for pituitary or stalk lesions. Copeptin levels were measured before surgery, 1 hour after extubation, and on postoperative days 1, 2, 7, and 90.

RESULTS

Among 73 patients, 23 patients (31.5%) developed DPH. The baseline ratio of copeptin to serum sodium level showed the highest predictive performance (area under the curve [AUROC], 0.699), and its optimal cutoff to maximize Youden's index was 2.5×10-11, with a sensitivity of 91.3% and negative predictive value of 92.0%. No significant predictors were identified for patients with transient arginine vasopressin (AVP) deficiency. However, for patients without transient AVP deficiency, the copeptin-to-urine osmolarity ratio at baseline demonstrated the highest predictive performance (AUROC, 0.725). An optimal cutoff of 6.5×10-12 maximized Youden's index, with a sensitivity of 92.9% and a negative predictive value of 94.1%.

CONCLUSION

The occurrence of DPH can be predicted using baseline copeptin and its ratio with serum sodium or urine osmolarity only in patients without transient AVP deficiency after pituitary surgery.

Predictors and dynamic online nomogram for postoperative delayed hyponatremia after endoscopic transsphenoidal surgery for pituitary adenomas: a single-center, retrospective, observational cohort study with external validation

BACKGROUND

Postoperative delayed hyponatremia (PDH) is a major cause of readmission after endoscopic transsphenoidal surgery (eTSS) for pituitary adenomas (PAs). However, the risk factors associated with PDH have not been well established, and the development of a dynamic online nomogram for predicting PDH is yet to be realized. We aimed to investigate the predictive factors for PDH and construct a dynamic online nomogram to aid in its prediction.

METHODS

We analyzed the data of 226 consecutive patients who underwent eTSS for PAs at the Department of Neurosurgery in Jinling Hospital between January 2018 and October 2020. An additional 97 external patients were included for external validation. PDH was defined as a serum sodium level below 137 mmol/L, occurring on the third postoperative day (POD) or later.

RESULTS

Hyponatremia on POD 1-2 (OR = 2.64, P = 0.033), prothrombin time (PT) (OR = 1.78, P = 0.008), and percentage of monocytes (OR = 1.22, P = 0.047) were identified as predictive factors for PDH via multivariable logistic regression analysis. Based on these predictors, a nomogram was constructed with great discrimination in internal validation (adjusted AUC: 0.613-0.688) and external validation (AUC: 0.594-0.617). Furthermore, the nomogram demonstrated good performance in calibration plot, Brier Score, and decision curve analysis. Subgroup analysis revealed robust predictive performance in patients with various clinical subtypes and mild to moderate PDH.

CONCLUSIONS

Preoperative PT and the percentage of monocytes were, for the first time, identified as predictive factors for PDH. The dynamic nomogram proved to be a valuable tool for predicting PDH after eTSS for PAs and demonstrated good generalizability. Patients could benefit from early identification of PDH and optimized treatment decisions.

Fluid Restriction Reduces Delayed Hyponatremia and Hospital Readmissions After Transsphenoidal Surgery

CONTEXT

Postoperative hyponatremia leads to prolonged hospital length of stay and readmission within 30 days.

OBJECTIVE

To assess 3 strategies for reducing rates of postoperative hyponatremia and analyze risk factors for hyponatremia.

DESIGN

Two retrospective analyses and 1 prospective study.

SETTING

Tertiary referral hospital.

PATIENTS

Patients undergoing transsphenoidal surgery for pituitary adenomas and other sellar and parasellar pathologies.

INTERVENTION(S)

Phase 1: no intervention. Phase 2: postoperative day (POD) 7 sodium testing and patient education. Phase 3: fluid restriction to 1 L/day on discharge in addition to phase 2 interventions.

MAIN OUTCOME MEASURES

Rates of early and delayed hyponatremia and readmissions. Secondary outcomes were risk factors for hyponatremia and readmission costs.

RESULTS

In phase 1, 296 patients underwent transsphenoidal surgery. Twenty percent developed early and 28% delayed hyponatremia. Thirty-eight percent underwent POD 7 sodium testing. Readmission rates were 15% overall and 4.3% for hyponatremia. In phase 2 (n = 316), 22% developed early and 25% delayed hyponatremia. Eighty-nine percent complied with POD 7 sodium testing. Readmissions were unchanged although severity of hyponatremia was reduced by 60%. In phase 3 (n = 110), delayed hyponatremia was reduced 2-fold [12.7%, relative risk (RR) = 0.52] and readmissions 3-fold [4.6%, RR = 0.30 (0.12-0.73)]; readmissions for hyponatremia were markedly reduced. Hyponatremia readmission increased costs by 30%.

CONCLUSIONS

Restricting fluid to 1 L/day on discharge decreases rates of delayed hyponatremia and readmissions by 50%. Standardized patient education and POD 7 sodium testing decreases severity of hyponatremia but does not impact readmission rates. These protocols should be considered standard practice for patients undergoing transsphenoidal surgery.

Predictors of Delayed Hyponatraemia After Surgery for Pituitary Tumour

Delayed hyponatraemia(DH) is a common complication following trans-sphenoidal surgery(TSS) for pituitary tumour. We evaluated the prevalence of DH following TSS, and assessed the factors associated with DH, including early post-operative diabetes insipidus(EPDI). This retrospective study included 100 TSS for pituitary tumours in 98 patients, over a period of 26 months. Subjects were divided into two groups: those who developed hyponatraemia and those who did not develop hyponatraemia, during post-operative days 4 to 14. The clinical characteristics and peri-operative parameters were compared between the two groups, to identify factors predicting DH. The mean age of the patients was 42.0±13.6 years, 58 (59%) were females and 61 (61%) had functional tumours. Thirty-six patients(36%) developed DH following TSS of whom majority(58%) were diagnosed on post-operative days 7 and 8; only 8/36 (22%) were symptomatic. Syndrome of inappropriate antidiuretic hormone secretion(SIADH) was found to be the most common aetiology of DH. On logistic regression analysis, intra-operative cerebrospinal fluid(CSF) leak (OR 5.0; 95% CI 1.9-13.8; p=0.002), EPDI (OR 3.4; 95% CI 1.3-9.2; p=0.015) and peri-operative steroid use (OR 3.6; 95% CI 1.3-9.8; p=0.014) were found to be significantly associated with DH. In conclusion, EPDI, intra-operative CSF leak and peri-operative steroid use were significant predictors of DH. EPDI predicts moderate to severe hyponatraemia with 80% specificity but has low sensitivity(47%). As most patients have asymptomatic hyponatraemia, serum sodium measurement on POD 7 to 10 would be helpful to identify DH in patients at increased risk.

Machine learning models predict delayed hyponatremia post-transsphenoidal surgery using clinically available features

PURPOSE

Delayed hyponatremia (DHN), a unique complication, is the leading cause of unexpected readmission after pituitary surgery. Therefore, this study aimed to develop tools for predicting postoperative DHN in patients undergoing endoscopic transsphenoidal surgery (eTSS) for pituitary neuroendocrine tumors (PitNETs).

METHODS

This was a single-center, retrospective study involving 193 patients with PitNETs who underwent eTSS. The objective variable was DHN, defined as serum sodium levels < 135 mmol/L at ≥ 1 time between post operative days 3 and 9. We trained four machine learning models to predict this objective variable using the clinical variables available preoperatively and on the first postoperative day. The clinical variables included patient characteristics, pituitary-related hormone levels, blood test results, radiological findings, and postoperative complications.

RESULTS

The random forest (RF) model demonstrated the highest (0.759 ± 0.039) area under the curve of the receiver operating characteristic curve (ROC-AUC), followed by the support vector machine (0.747 ± 0.034), the light gradient boosting machine (LGBM: 0.738 ± 0.026), and the logistic regression (0.710 ± 0.028). The highest accuracy (0.746 ± 0.029) was observed in the LGBM model. The best-performing RF model was based on 24 features, nine of which were clinically available preoperatively.

CONCLUSIONS

The proposed machine learning models with pre- and post-resection features predicted DHN after the resection of PitNETs.

Delayed postoperative hyponatremia in patients with acromegaly: incidence and predictive factors

PURPOSE

Delayed postoperative hyponatremia (DPH) is a unique complication of transsphenoidal surgery (TSS) in pituitary tumors. Growth hormone (GH) enhances renal sodium reabsorption; however, the association between postoperative GH reduction and DPH in acromegaly is unclear. This study was performed to clarify the incidence of and the predictive factors for DPH in patients with acromegaly who underwent TSS.

METHODS

Ninety-four patients with active acromegaly were examined retrospectively. During the postoperative course, patients with serum sodium levels ≤ 134 mEq/L were classified into the DPH group. We compared basic clinical characteristics, tumor characteristics, and preoperative and postoperative examination findings between the DPH and non-DPH groups.

RESULTS

DPH occurred in 39 patients (41.5%), and the lowest serum sodium levels were generally observed during postoperative days (PODs) 7-9. They needed a 3-day longer hospital stay than those without DPH. The DPH group had lower preoperative body weight and body mass index. In addition, a transient increase in body weight during PODs 5-7 occurred with a transient decrease in urinary volume in the DPH group. Preoperative and postoperative GH and insulin-like growth factor-1 levels did not differ between the two groups.

CONCLUSION

The findings suggested that lower preoperative weight and a postoperative transient gain in body weight are associated with an increased risk of DPH in acromegaly patients undergoing transsphenoidal surgery.

Optimizing Perioperative Care in Transsphenoidal Pituitary Surgery: Considerations for Enhanced Recovery After Surgery

OBJECTIVE

To identify key recommendations for maximizing the efficiency and efficacy of perioperative care in transsphenoidal pituitary surgery.

METHODS

The authors performed a comprehensive literature search of Enhanced Recovery After Surgery protocols implemented for patients undergoing transsphenoidal adenomectomy (TSA); individual recommendations were abstracted, and the evidence base thoroughly reviewed.

RESULTS

The authors identified 19 individual recommendations pertinent to the care of patients undergoing TSA, which were subdivided into preoperative (n=6), intraoperative (n=6), and postoperative (n=7) interventions. Key factors recommended for minimizing length of stay, preventing readmission, and improving patient outcomes included comprehensive patient education, multidisciplinary evaluation, avoidance of routine lumbar drain placement and nasal packing, and rigorous postoperative monitoring of pituitary function and salt-water imbalances. The overall level of evidence for 7/19 (37%) implemented recommendations was found to be low, suggesting a need for continued research in this patient population.

CONCLUSION

Several key interventions should be considered in the development of Enhanced Recovery After Surgery protocols for TSA, which may aid in further decreasing length of stay and promoting positive patient outcomes.

The Potential of Self-Assessment and Associated Factors for Delayed Symptomatic Hyponatremia Following Transsphenoidal Surgery: A Single Center Experience

(1) Background: We identified screening parameters and associated factors for delayed, symptomatic hyponatremia (DSH) following inpatient discharge after transsphenoidal surgery (TSS). (2) Methods: In this prospective, monocentric study, 108 patients who underwent TSS for pituitary pathologies were included, provided with a questionnaire and instructed to document urine specific gravity, fluid intake/urine output, body weight and clinical symptoms for every of five days following discharge from hospital. (3) Results: The overall incidence of DSH within 14 days following discharge from the hospital was 14.8% (n = 9). Symptomatic patients presented on average 8.6 days after surgery. Mild DSH was present in 3.3% of the patients, moderate in 1.6% and severe hyponatremia in 9.8% of patients. Female sex (p = 0.02) and lower BMI (p = 0.02), as well as nausea (66.7%; p < 0.01) and emesis (33.3%; p < 0.05), were associated with DSH. A significant weight delta between morning and afternoon weight two days before the event of DSH between both groups (1.26 kg (n = 5) vs. 0.79 kg (n = 52), p < 0.05) was detected. (4) Conclusions: Handing out a symptom questionnaire at discharge seems to be an easy and feasible tool for the detection of DSH after hospital discharge.

Prevention of Hyponatremia After Transsphenoidal Surgery: A Systematic Review

Context: Pituitary adenomas are amongst the most common tumors with a low mortality rate compared to other intracranial malignancies. Delayed hyponatremia (DH) is a common finding after transsphenoidal resection (TSS), which is the basis for the management of these tumors. Although DH is one of the leading causes of readmission after TSS, no unified guidelines exist with regard to the prevention of this electrolyte disturbance. Objectives: This study aims to evaluate and compare existing preventive protocols for DH in order to identify and signify their common grounds. Methods: After a search in electronic databases, including PubMed (NCBI), Embase, Scopus, and Google Scholar with the keywords of “pituitary adenoma,” “hyponatremia,” “transsphenoid surgery”, “water electrolyte balance,” “patient readmission", six original articles were included in the study. Results: We found that a protocol that both identifies groups susceptible to DH (males, older individuals, and those with a lower BMI) and consists of fluid restriction, sodium supplementation, and regular serum sodium monitoring could be utilized to prevent DH in patients with pituitary adenomas after TSS. Conclusions: Further studies with a larger sample size must be conducted to compare existing protocols for preventing DH and also investigate post-surgery optimal fluid-restricted diets and corticosteroid therapy in these patients.

Impact of surgical factors on delayed hyponatremia in patients with nonfunctioning pituitary adenoma after endonasal endoscopic transsphenoidal procedure

PURPOSE

Delayed hyponatremia can occur after pituitary surgery, resulting in prolonged hospitalization. However, the influence of surgical factors after such a procedure has not been well established. The impact of surgery and related factors on delayed hyponatremia was investigated.

METHODS

This was a retrospective analysis of 137 consecutive patients who underwent transsphenoidal surgery for a nonfunctioning pituitary adenoma between 2008 and 2019. Preoperative (demographics, comorbidities), intraoperative (resection extent, operation time, blood loss volume, cerebrospinal fluid leak, tumor consistency), and postoperative [hematoma, meningitis, diabetes insipidus (DI), hormonal assessment] data were collected, with statistical analysis of each factor performed.

RESULTS

Among the 137 patients, delayed hyponatremia occurred in 31 (22.6%). Multivariate analysis revealed that those with hypertension had a significantly higher likelihood of avoiding delayed hyponatremia (p = 0.004). Although no correlations of direct surgical factors with delayed hyponatremia were found, multivariate analysis of indirect surgical factors showed that presence of a firm tumor, transient DI, and meningitis were significantly associated with delayed hyponatremia (p = 0.014, 0.001, and 0.047, respectively). There was also a significant association of severe hyponatremia with appearance of symptoms (p = 0.002).

CONCLUSION

There was a tendency for hypertension to be associated with delayed hyponatremia avoidance, with indirect surgical factors including tumor consistency, transient DI, and meningitis found to have an influence on delayed hyponatremia. It was concluded that attention should be given to non-hypertensive patients with a firm tumor, transient DI, or meningitis after pituitary surgery, as delayed hyponatremia may occur.

Predictive factors for delayed hyponatremia after transsphenoidal surgery in patients with Rathke's cleft cysts

Purpose

We aimed to assess factors influencing the occurrence of delayed hyponatremia after transsphenoidal surgery in patients with Rathke's cleft cysts (RCCs).

Methods

We retrospectively collected the clinical data of patients who underwent transsphenoidal surgery for RCCs from January 2014 to January 2022. Univariate and multivariate analyses were used to determine the factors influencing the occurrence of postoperative delayed hyponatremia.

Results

Of the 78 microscopic transsphenoidal surgery recipients with RCCs, 15 experienced postoperative delayed hyponatremia. There were 35 men and 43 women, and mean age was 43.75 ± 14.95 years. The clinical manifestations of RCCs were headache (62 cases, 79.5%), visual dysfunction (35 cases, 44.9%), endocrine dysfunction symptoms (12 cases, 15.4%). After transsphenoidal surgery, 93.5% (58/62) had improvements in headache, and 97.1% (34/35) had improved or resolved compressive visual symptoms. Delayed hyponatremia occurred on average on day 6.46 and lasted on average for 4.40 days. Logistic regression analysis showed that the independent influencing factor of delayed hyponatremia after transsphenoidal surgery in patients with RCCs was postoperative diaphragma sellae height.

Conclusion

Postoperative diaphragma sellae height was identified as an independent influencing factor for delayed hyponatremia after transsphenoidal surgery in patients with RCCs.

Risk factors for delayed postoperative hyponatremia in patients with non-functioning pituitary adenomas undergoing transsphenoidal surgery: A single-institution study

Purpose

We aimed to assess factors influencing the occurrence of delayed hyponatremia after transsphenoidal surgery (TSS) in patients with a non-functional pituitary adenoma (NFPA).

Methods

We retrospectively collected the clinical data of patients who underwent TSS for NFPA between January 2016 and January 2021. The pituitary region was preoperatively scanned with 3.0 T magnetic resonance imaging. The risk factors for delayed postoperative hyponatremia for NFPA were identified by univariate and multivariable logistic regression analysis.

Results

We selected 166 patients with NFPA who fulfilled the inclusion criteria. Delayed postoperative hyponatremia occurred in 28 patients and did not in 138. Multivariable logistic regression analyses demonstrated that higher odds of developing delayed postoperative hyponatremia were independently associated with larger craniocaudal dimension (OR = 1.128, P = 0.034), as well as preoperative hyperprolactinemia (OR = 2.618, P = 0.045) and larger preoperative pituitary stalk deviation angle (OR = 3.033, P = 0.022).

Conclusion

We identified the independent risk factors for delayed hyponatremia after TSS for NFPA; these included preoperative hyperprolactinemia, craniocaudal diameter, and preoperative pituitary stalk deviation angle.

Incidence and risk factors of delayed postoperative hyponatremia after endoscopic endonasal surgery for Rathke’s cleft cyst: A single-center study

Backgroud

Delayed postoperative hyponatremia (DPH) is common for sellar lesions. However, the true prevalence and associated factors of DPH after endoscopic endonasal surgery (EES) for Rathke’s cleft cyst (RCC) have not been studied in a large patient cohort.

Methods

A retrospective analysis was conducted over 6 years at our institution, and patients with RCC treated by EES were enrolled according to our inclusion criteria. Patient demographics, clinical characteristics, images, and surgical procedures were documented. Serum sodium was routinely measured before surgery, on postoperative day 1, and every 2 days thereafter until discharge. For patients with DPH, electrolyte, hematocrit, serum protein levels, and plasma and urinary osmolality were daily measured to explore potential etiology.

Results

Of the 149 eligible patients, 25 (16.8%) developed DPH, which was similar to other sellar lesions, except craniopharyngioma, in the same period in our institution. Significant risk factors suggested by univariate analysis were cyst location, requirement of postoperative hydrocortisone therapy, postoperative meningitis, intraoperative cerebrospinal fluid (CSF) leakage, and subtotal resection (STR) of the cyst wall (all p &lt; 0.05). In addition, other supplementary 11 cases of suprasellar RCC with different surgical strategies (aggressive resection) and relevant factors were enrolled into multivariate analysis. Suprasellar location [odds ratio (OR) 8.387, 95% confidence interval (CI) 1.014–69.365, p = 0.049], requirement of postoperative hydrocortisone therapy (OR 4.208, 95%CI 1.246–14.209, p = 0.021), and intraoperative CSF leakage (OR 6.631, 95%CI 1.728–25.440, p = 0.006) were found to be the independent predictors of DPH.

Conclusion

DPH is a common complication after EES for RCC. Suprasellar location, requirement of postoperative hydrocortisone therapy, and intraoperative CSF leakage are the most reliable risk factors. Cortisol deficiency and syndrome of inappropriate antidiuretic hormone (SIADH) are considered as the main etiologies of DPH in RCC. Conservative excision of the cyst wall may reduce DPH occurrence.

The management and outcome of hyponatraemia following transsphenoidal surgery: a retrospective observational study

Purpose

Hyponatraemia is a common complication following transsphenoidal surgery. However, there is sparse data on its optimal management and impact on clinical outcomes. The aim of this study was to evaluate the management and outcome of hyponatraemia following transsphenoidal surgery.

Methods

A prospectively maintained database was searched over a 4-year period between January 2016 and December 2019, to identify all patients undergoing transsphenoidal surgery. A retrospective case-note review was performed to extract data on hyponatraemia management and outcome.

Results

Hyponatraemia occurred in 162 patients (162/670; 24.2%) with a median age of 56 years. Female gender and younger age were associated with hyponatraemia, with mean nadir sodium being 128.6 mmol/L on postoperative day 7. Hyponatraemic patients had longer hospital stay than normonatraemic group with nadir sodium being inversely associated with length of stay (p < 0.001). In patients with serum sodium ≤ 132 mmol/L, syndrome of inappropriate antidiuretic hormone secretion (SIADH) was the commonest cause (80/111; 72%). Among 76 patients treated with fluid restriction as a monotherapy, 25 patients (25/76; 32.9%) did not achieve a rise in sodium after 3 days of treatment. Readmission with hyponatraemia occurred in 11 cases (11/162; 6.8%) at a median interval of 9 days after operation.

Conclusion

Hyponatraemia is a relatively common occurrence following transsphenoidal surgery, is associated with longer hospital stay and risk of readmission and the effectiveness of fluid restriction is limited. These findings highlight the need for further studies to better identify and treat high-risk patients, including the use of arginine vasopressin receptor antagonists.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00701-022-05134-9.

Novel Nomograms to Predict Delayed Hyponatremia After Transsphenoidal Surgery for Pituitary Adenoma

OBJECTIVE

This study aimed to develop a nomogram of clinical variables and magnetic resonance imaging scans to predict delayed hyponatremia after transsphenoidal surgery for pituitary adenoma.

METHODS

Patients who underwent transsphenoidal surgery for pituitary adenoma in Fuzong Clinical Medical College of Fujian Medical University between January 2012 and December 2020 were retrospectively investigated. Medical records, MRI findings, and laboratory examination results were recorded as candidate variable predictors of delayed hyponatremia. A nomogram to predict delayed hyponatremia was formulated based on the multivariable model of risk factors. The predictive accuracy and discriminative ability of the nomogram were assessed using the receiver operating characteristic (ROC) curve, calibration plot, and decision curve analyses. The model underwent prospective validation in three medical centers with patients who underwent transsphenoidal surgery for pituitary adenoma between January 2021 and February 2022.

RESULTS

The model that incorporated the postoperative length of "measurable pituitary stalk," pituitary stalk deviation angle difference, postoperative diabetes insipidus, sinking depth of diaphragma sellae, and blood sodium level on the second postoperative day was developed and presented as the nomogram of the training cohort. The nomogram achieved area under the ROC curve (AUCs) of 0.806 and 0.849 for the training cohort and the testing cohort, respectively, and displayed good calibration. Decision curve analysis showed that the nomogram was clinically useful when the threshold probability was 13-96%.

CONCLUSIONS

We developed a nomogram to evaluate the individualized prediction of delayed hyponatremia after transsphenoidal surgery for pituitary adenomas.

Diaphragma sellae sinking can predict the onset of hyponatremia after transsphenoidal surgery for pituitary adenomas

PURPOSE

Sinking of the diaphragma sellae (DS) may stretch the pituitary stalk, which in turn impairs neurohypophyseal function; thus, it may play a role in the development of postoperative hyponatremia. We aimed to assess the factors influencing the development of hyponatremia after transsphenoidal surgery (TSS) for pituitary adenomas and analyze the effect of DS sinking on hyponatremia.

METHODS

After applying the inclusion and exclusion criteria, we retrospectively analyzed the clinical data of patients with pituitary adenoma who underwent TSS. The pituitary gland was scanned using a 3.0-T magnetic resonance imaging, and sagittal and coronal images were acquired. We evaluated the following: preoperative and postoperative hypothalamus‒pituitary‒thyroid axis function, hypothalamus‒pituitary‒adrenal axis function, intra-operative cerebrospinal fluid leaks, diabetes insipidus, hyponatremia, time from the day of surgery to the day of discharge, and time of hyponatremia onset.

RESULTS

Of the 460 patients who had microscopic TSS for pituitary adenoma, 83 experienced postoperative hyponatremia. Hyponatremia occurred approximately 5.25 days postoperatively and persisted for 5.54 days. The lowest average blood sodium level was 123.9 mEq/L, which occurred at 7.49 days after surgery. Logistic regression analysis showed that the risk of hyponatremia was greater for patients with a significant DS sinking depth, a large pituitary stalk deviation angle difference, and a longer postoperative "measurable pituitary stalk". The difference in blood sodium levels between pre-TSS and 2 days post-TSS was also an independent predictor of postoperative hyponatremia onset.

CONCLUSION

DS sinking plays an important role in predicting hyponatremia onset after TSS for pituitary adenomas.

The Difference Between Preoperative and Postoperative Pituitary Stalk Deviation Angles Can Predict Delayed Hyponatremia After Transsphenoidal Surgery

OBJECTIVE

Our aim was to assess the factors influencing the development of delayed hyponatremia after transsphenoidal surgery (TSS) for pituitary adenomas and analyze the effect of the difference between preoperative and postoperative pituitary stalk deviation angles on delayed hyponatremia.

METHODS

A retrospective study was performed on the clinical data of patients with pituitary adenomas who were treated with TSS at a single institution. On the basis of the observation of indicators such as pituitary stalk deviation angle and length of "measurable pituitary stalk" on magnetic resonance imaging, we determined the predictors of postoperative delayed hyponatremia through univariate and multivariate analyses.

RESULTS

Microscopic TSS was performed in 422 patients with pituitary adenoma, of whom 66 experienced postoperative delayed hyponatremia. Logistic regression analysis showed that the risk of delayed hyponatremia was greater for patients with a large difference between preoperative and postoperative pituitary stalk deviation angle (odds ratio = 1.040, 95% confidence interval: 1.018-1.051; P < 0.001) and a large difference in the "measurable pituitary stalk" (odds ratio = 1.128, 95% confidence interval: 1.011-1.258; P = 0.032), and patients with high blood sodium on the second day after surgery have a lower probability of developing delayed hyponatremia.

CONCLUSIONS

This study is the first to suggest the important role of the difference between preoperative and postoperative pituitary stalk deviation angles in predicting the development of delayed hyponatremia after TSS for pituitary adenomas.

Fluid Restriction After Transsphenoidal Surgery for the Prevention of Delayed Hyponatremia: A Systematic Review and Meta-Analysis

OBJECTIVE

Delayed hyponatremia is the primary cause of readmission after transsphenoidal surgery, with a reported incidence of 9% to 30.7%. Studies have failed to identify consistent predictive factors for postoperative hyponatremia; thus, it is difficult to determine patients that are at a high risk. Fluid restriction is one approach for the prevention of hyponatremia. We have performed a meta-analysis and systematic review of the literature to evaluate the impact of fluid restriction on hyponatremia and hospital readmissions.

METHODS

Ovid EMBASE, PubMed, Scopus, and Cochrane were searched from inception to May 2021, using the Population, Intervention, Comparison, Outcome, and Study question format: Do patients who underwent transsphenoidal surgery and followed a postoperative fluid restriction regimen differ in terms of hyponatremia and readmission rates? Studies that implemented fluid restriction and reported hyponatremia and/or readmission rates were included for analysis. Data were pooled by meta-analysis and analyzed using fixed effect and random effect models.

RESULTS

A total of 143 manuscripts representing 103 unique studies were identified, with 5 studies included for analysis, yielding a pooled cohort of 1586 patients: 594 on fluid restriction protocols and 992 control patients. Fluid restriction protocols ranged from 1.0 to 2.5 L and varied in the length time between postoperative days 1 to 15. Patients on fluid restriction had a decreased risk of hyponatremia (risk ratio: 0.34; 95% CI, 0.21-0.57; P < .00001) and readmission due to hyponatremia (risk ratio: 0.24; 95% CI, 0.09-0.63; P = .0038).

CONCLUSION

Postoperative fluid restriction after transsphenoidal surgery represents an effective method for the prevention of hyponatremia and hospital readmission and has the potential to decrease health care costs.

Increased oxytocin release precedes hyponatremia after pituitary surgery

PURPOSE

The syndrome of inappropriate secretion of antidiuretic hormone (SIADH) is a well-known complication of transsphenoidal pituitary surgery, related to inappropriate secretion of arginine vasopressin (AVP). Its diagnosis is based on hyponatremia, with a peak of occurrence around day 7 after surgery and, to date, no early marker has been reported. In particular, copeptin levels are not predictive of hyponatremia in this case. Oxytocin (OXT) is secreted into the peripheral blood by axon terminals adjacent to those of AVP neurons in the posterior pituitary. Besides its role in childbirth and lactation, recent evidences suggested a role for OXT in sodium balance. The contribution of this hormone in the dysnatremias observed after pituitary surgery has however never been investigated.

METHODS

We analyzed the urinary output of OXT in patients subjected to transsphenoidal pituitary surgery.

RESULTS

While OXT excretion remained stable in patients who presented a normonatremic postoperative course, patients who were later diagnosed with SIADH-related hyponatremia presented with a significantly increased urinary secretion of OXT 4 days after surgery.

CONCLUSION

Taken together, these results show for the first time that urinary OXT output remains normally stable after transsphenoidal pituitary surgery. OXT excretion however becomes abnormally high on or around 4 days after surgery in patients later developing hyponatremia, suggesting that this abnormal dynamics of OXT secretion might serve as an early marker for transsphenoidal surgery-related hyponatremia attributed to SIADH.

30-Day Readmissions and Coordination of Care Following Endoscopic Transsphenoidal Pituitary Surgery: Experience with 409 Patients

Objective The study aimed to (1) quantify readmission rates and common causes of readmission following endoscopic transsphenoidal pituitary surgery (ETPS); (2) identify risk factors that may predict readmission within 30 days; (3) assess postoperative care coordination with endocrinology follow-up; and (4) identify patients for whom targeted interventions may reduce 30-day readmissions.

Methods Retrospective quality improvement review of patients with pituitary adenoma who underwent ETPS from December 2010 to 2018 at a single tertiary care center.

Results A total of 409 patients were included in the study, of which 57 (13.9%) were readmitted within 30 days. Hyponatremia was the most common cause of readmission (4.2%) followed by pain/headache (3.9%), cerebrospinal fluid leak (3.4%), epistaxis (2.7%), hypernatremia (1.2%), and adrenal insufficiency (1.2%). Patients with hyponatremia were readmitted significantly earlier than other causes (4.3 ± 2.2 vs. 10.6 ± 10.9 days from discharge, p = 0.032). Readmitted patients had significantly less frequent outpatient follow-up with an endocrinologist than the nonreadmitted cohort (56.1 vs. 70.5%, p = 0.031). Patients who had outpatient follow-up with an endocrinologist were at lower risk of readmission compared with those without (odds ratio: 0.46; 95% confidence interval: 0.24–0.88).

Conclusion Delayed hyponatremia is one of the most common causes of 30-day readmission following ETPS. Postoperative follow-up with an endocrinologist may reduce risk of 30-day readmission following ETPS.

Implications for Clinical Practice A multidisciplinary team incorporating otolaryngologist, neurosurgeons, and endocrinologist may identify patients at risk of 30-day readmissions. Protocols checking serum sodium within 1 week of surgery in conjunction with endocrinologist to tailor fluid restriction may reduce readmissions from delayed hyponatremia.

Incidence and Factors Associated with Postoperative Delayed Hyponatremia after Transsphenoidal Pituitary Surgery: A Meta-Analysis and Systematic Review

INTRODUCTION

Postoperative delayed hyponatremia is a complication associated with transsphenoidal pituitary surgery. Due to a wide spectrum of symptoms, the reported incidence and predictors of postoperative delayed hyponatremia vary among studies, and this deserves to be reviewed systematically.

METHODS

PubMed, EMBASE, and CENTRAL databases were searched until September 1, 2020. Studies were included when (1) the event number of delayed hyponatremia after transsphenoidal pituitary surgery was reported, or (2) the associated factors of such complication were evaluated.

RESULTS

A total of 27 studies were included for meta-analysis. The pooled incidence of overall and symptomatic delayed hyponatremia was 10.5% (95% confidence interval (CI) = 7.4-14.7%) and 5.0% (95% CI = 3.6-6.9%), respectively. No overt variations of the pooled estimates were observed upon subgroups stratified by endoscopic and microscopic procedure, publication year, and patients' age. In addition, 44.3% (95% CI = 29.6-60.2%) of unplanned hospital readmissions within 30 days were caused by delayed hyponatremia. Among the predictors evaluated, older age was the only significant factor associated with increased delayed hyponatremia (odds ratio = 1.16, 95% CI = 1.04-1.29, P = 0.006).

CONCLUSION

This meta-analysis and systematic review evaluated the incidence of postoperative delayed hyponatremia and found it as a major cause of unplanned readmissions after transsphenoidal pituitary surgery. Older patients are more prone to such complications and should be carefully followed. The retrospective nature and heterogeneity among the included studies and the small number of studies used for risk factor evaluation might weaken the corresponding results. Future prospective clinical studies are required to compensate for these limitations.

Delayed Postoperative Hyponatremia Following Endoscopic Transsphenoidal Surgery for Non-Adenomatous Parasellar Tumors

Little is known about delayed postoperative hyponatremia (DPH) accompanied with transsphenoidal surgery for non-adenomatous skull base tumors (NASBTs). Consecutive data on 30 patients with parasellar NASBT was retrospectively reviewed with detailed analyses on perioperative serial sodium levels. Serological DPH (sodium ≤ 135 mmol/L) was observed in eight (27%), with four (13%) of them being symptomatic. DPH developed on postoperative day 7-12 where the mean sodium levels were 134 mmol/L (a mean of 7 mmol/L drop from the baseline) in asymptomatic and 125 mmol/L (a mean of 17.5 mmol/L drop from the baseline) in symptomatic DPH. Serological DPH was accompanied with "weight loss and hemoconcentration (cerebral salt wasting type)" in four (50%), "weight gain and hemodilution (syndrome of inappropriate antidiuretic hormone secretion type)" in three (38%), and no significant weight change in one. Intraoperative extradural retraction of the pituitary gland was the only significant factor for serological DPH (p = 0.035; odds ratio, 12.25 (95% confidence interval, 1.27-118.36)). DPH should be recognized as one of the significant postsurgical complications associated with TSS for NASBTs. Although the underlying mechanism is still controversial, intraoperative extradural compression of the pituitary gland and subsequent dysregulation of the hypothalamo-hypophyseal axis may be responsible.

Feasibility of machine learning based predictive modelling of postoperative hyponatremia after pituitary surgery

PURPOSE

Hyponatremia after pituitary surgery is a frequent finding with potential severe complications and the most common cause for readmission. Several studies have found parameters associated with postoperative hyponatremia, but no reliable specific predictor was described yet. This pilot study evaluates the feasibility of machine learning (ML) algorithms to predict postoperative hyponatremia after resection of pituitary lesions.

METHODS

Retrospective screening of a prospective registry of patients who underwent transsphenoidal surgery for pituitary lesions. Hyponatremia within 30 days after surgery was the primary outcome. Several pre- and intraoperative clinical, procedural and laboratory features were selected to train different ML algorithms. Trained models were compared using common performance metrics. Final model was internally validated on the testing dataset.

RESULTS

From 207 patients included in the study, 44 (22%) showed a hyponatremia within 30 days postoperatively. Hyponatremic measurements peaked directly postoperatively (day 0-1) and around day 7. Bootstrapped performance metrics of different trained ML-models showed largest area under the receiver operating characteristic curve (AUROC) for the boosted generalized linear model (67.1%), followed by the Naïve Bayes classifier (64.6%). The discriminative capability of the final model was assessed by predicting on unseen dataset. Large AUROC (84.3%; 67.0-96.4), sensitivity (81.8%) and specificity (77.5%) with an overall accuracy of 78.4% (66.7-88.2) was reached.

CONCLUSION

Our trained ML-model was able to learn the complex risk factor interactions and showed a high discriminative capability on unseen patient data. In conclusion, ML-methods can predict postoperative hyponatremia and thus potentially reduce morbidity and improve patient safety.