Predictive value of preoperative retinal nerve fiber layer thickness for postoperative visual recovery in patients with chiasmal compression

Influence of Tumor Characteristics on Visual Field Outcomes After Pituitary Adenoma Surgery

BACKGROUND

There were few reports about the influence of tumor characteristics on the postoperative visual field outcomes after transsphenoidal surgery for pituitary adenoma. The purpose of this study was to explore the tumor characteristics that influenced perioperative visual field changes.

METHODS

Patients who underwent transsphenoidal surgery under a diagnosis of pituitary adenoma at the Kyoto University Hospital between April 2012 and December 2018 were retrospectively enrolled. Correlations among circumpapillary retinal nerve fiber layer thickness, preoperative and postoperative mean deviation (MD) of visual field, MD change after the surgery, and maximum tumor diameter were evaluated by measuring Pearson correlation coefficient. We evaluated the influences on postoperative MD using a generalized estimating equation for univariate and multivariate regression analyses. We also compared the characteristics of cystic and solid tumors.

RESULTS

Thirty-two eyes of 18 patients were included in this study (9 male and 9 female patients). Postoperative MD positively correlated with maximum tumor diameter only in multivariate regression {β = 0.22 (95% confidence interval [CI], 0.004-0.43), P = 0.046}, although maximum tumor diameter negatively correlated with postoperative MD in univariate regression (β = -0.16 [95% CI, -0.58 to 0.26], P = 0.46). In the investigation of perioperative MD changes, eyes with cystic tumors showed significantly better improvement those with solid tumors (8.93 ± 7.85 vs 0.18 ± 6.56 dB, P = 0.007).

CONCLUSIONS

Cystic and solid tumors show different characteristics of visual loss and visual field defects. The MD in eyes with cystic tumors improved significantly more than that in eyes with solid tumors.

A pilot study of combined optical coherence tomography and diffusion tensor imaging method for evaluating microstructural change in the visual pathway of pituitary adenoma patients

Background

RNFL thickness measured by optical coherence tomography (OCT) and visual pathway measured by diffusion tensor imaging (DTI) can be used to predict visual field recovery, respectively. However, the relationship between RNFL thickness and visual pathway injury in patients with pituitary adenoma (PA) remains unclear. This study aims to evaluate the combining DTI and OCT methods in observing the microstructural change in the visual pathway in patients with PA.

Methods

Twenty-nine patients who were diagnosed with PA were included in the study group, and 29 healthy subjects were included as the control group. OCT detected the thickness of circumpapillary retinal nerve fiber layer (CP-RNFL) and ganglion cell layer (GCL). DTI measured the values of fractional anisotropy (FA) and apparent diffusion coefficient (ADC). Correlation between CP-RNFL and GCL thickness and FA and ADC values was analyzed in the study group.

Results

Compared with the control group, the FA values of the bilateral optic nerve, chiasma, bilateral optic tract, and left optic radiation in the study group were reduced, and the ADC values of the bilateral optic nerve and optic chiasma were increased. Correlation analysis showed that the FA value of the optic chiasma was positively correlated with the average thickness of RNFL, the CP-RNFL thickness in the nasal and temporal retinal quadrants in both eyes, as well as the thickness of macular ring GCL in the nasal, supra, and inferior quadrants. The FA values of the optic nerve, optic chiasma, optic tract, and optic radiation were positively correlated with CP-RNFL thickness in the nasal and temporal quadrants.

Conclusion

Combined DTI and OCT can provide a comprehensive understanding of the microscopic changes in the structure and function of the whole visual pathway in patients with PA.

Optical coherence tomography: a window to the brain?

First described in 1991 and introduced into clinical practice in 1996, optical coherence tomography (OCT) now has a very extensive role in many different areas of ophthalmological practice. It is non-invasive, cheap, highly reproducible, widely available and easy to perform. OCT also has a role in managing patients with neurological disorders, particularly idiopathic intracranial hypertension. This review provides an overview of the technology underlying OCT and the information it can provide that is relevant to the practising neurologist. Particular conditions discussed include papilloedema, optic disc drusen, multiple sclerosis and neuromyelitis optica, other optic neuropathies, compression of the anterior visual pathway and various neurodegenerative conditions.

Temporal patterns of visual recovery following pituitary tumor resection: A prospective cohort study

Significant restoration of visual function can occur following pituitary tumor resection, although the time course of visual recovery remains poorly understood. This single-centre, two-year, prospective cohort study investigated the temporal patterns of visual recovery in consecutive patients undergoing pituitary tumor resection, between 2009 and 2018. Eyes were stratified based on pre-operative optical coherence tomography (OCT) retinal nerve fibre layer (RNFL) thickness measurements, with thin RNFL being defined as those within the fifth-percentile of age-matched normative values, and normal RNFL as those above the fifth-percentile. Visual function and OCT parameters were assessed pre-operatively, and at 6 weeks, 6 months, and 2 years post-operatively. 456 eyes of 228 patients (mean ± SD age, 53 ± 15 years) were included, of which 114 (25%) eyes had thin RNFL pre-operatively. Visual field recovery was observed in both groups during the first 6 weeks post-operatively (all Q ≤ 0.02), although improvements in visual field parameters between 6 weeks to 6 months were limited to eyes with thin RNFL (both Q < 0.05). No further improvements in visual function were detected beyond 6 months in both groups (both Q > 0.50). Similar trends were observed in linear regression analysis according to baseline visual function in both groups. In summary, eyes with normal RNFL thickness at baseline experienced most of their recovery within the first six weeks following surgery, while eyes with thin RNFL exhibited gradual improvements during the first six months. These findings have important implications when providing patient counselling and prognostication in the pre-operative setting.

Prognostic Utility of Optical Coherence Tomography for Long-Term Visual Recovery Following Pituitary Tumor Surgery

PURPOSE

To investigate the association between optical coherence tomography (OCT) parameters and long-term visual recovery following optic chiasm decompression surgery.

DESIGN

Prospective cohort study.

METHODS

Consecutive patients who underwent pituitary or parasellar tumor resection between January 2009 to December 2018 were recruited in a single-center, 2-year prospective, longitudinal cohort study. Best-corrected visual acuity, visual fields, and OCT retinal nerve fiber layer (RNFL) thickness, macular thickness and volume were assessed preoperatively, and at 6 weeks, 6 months, and 2 years postoperatively. Long-term visual field recovery and maintenance were defined as a mean deviation of >-3 at 24 months, and visual acuity recovery and maintenance were defined as a logarithm of minimal angle of resolution (logMAR) of 0 (Snellen 20/20) or better at 24 months.

RESULTS

A total of 239 patients (129 men, 110 women; mean ± SD age: 52 ± 16 years) were included. Multiple logistic regression analysis demonstrated that increased inferior RNFL thickness (per 10 μm) was associated with higher odds of long-term visual field recovery and maintenance (odds ratio [OR]: 1.26; 95% confidence interval [CI]: 1.12-1.41; Q < 0.001), and greater superior RNFL thickness (per 10 μm) was associated with higher odds of visual acuity recovery and maintenance (OR: 1.13; 95% CI: 1.03-1.27; Q = 0.031). A multivariable risk prediction model developed for long-term visual field recovery and maintenance that incorporated age, preoperative visual function, and RNFL thickness demonstrated C-statistics of 0.83 (95% CI: 0.72-0.94).

CONCLUSION

Preoperative RNFL thickness was associated with long-term visual recovery and maintenance following chiasmal decompression. The multivariable risk prediction model developed in the present study may assist with preoperative patient counseling and prognosis.

Visual Outcomes After Pituitary Surgery

Visual signs and symptoms are a common manifestation of pituitary adenomas from compression or ischemia of the optic nerves and optic chiasm. Although bitemporal hemianopsia is a classic presenting visual field deficit, additional visual disturbances can result from these tumors. After endoscopic endonasal pituitary surgery, most patients have improvement in visual symptoms. Preoperative factors including retinal nerve fiber layer thickness, severity of preoperative deficit, duration of visual symptoms, tumor size, extent of resection, and patient age serve as possible predictors of postoperative visual outcomes.

Cell activity during peripheral nerve defect repair process using a nerve scaffold

Peripheral nerve defects, but not artificial nerves, are repaired by endogenous cells. We examined cell activity during the repair process in the presence of autologous nerves and artificial preparations in order to guide future artificial nerve fabrication. PLGA tubes, nerve scaffolds comprising a PLGA tube plus 6,000 fibroin fibers, or autologous nerves were implanted into 10 mm rat sciatic nerve defects (n = 60 per group). Over a period of 1-20 weeks after nerve grafting, sections were stained and imaged to distinguish the cell types present and we quantified the recovery of motor and sensory function in the surgically implanted limb. We observed a decreasing trend in inflammatory cell and fibroblast counts over time which ranked in magnitude as: (PLGA group > nerve scaffold > autologous nerve> sham) and an opposite trend in Schwann cell counts. Differences in withdrawal time from hot water and static sciatic index (SSI) indicated that, after repair, sensory and motor function were best in the sham group, followed by the autologous group, the nerve scaffold group, and the PLGA group. These findings indicate that the inflammatory reaction is significant in the first two weeks after nerve grafting, followed by the rebirth of fibroblasts and Schwann cells, which guide axon regeneration. This inflammatory response was a fundamental stage of peripheral defect repair, but a weaker inflammatory response corresponded to better recovery of sensorimotor functional.