Optic Canal Decompression: Comparison of 2 Surgical Techniques

Cranio-Orbital Pretemporal Approach for Microsurgical Resection of Hypothalamic Rosette Forming Glioneuronal Tumor with Reversal of Preoperative Blindness: 2-Dimensional Operative Video

The hypothalamic region is susceptible to involvement of several processes.1 Lesions in this region remain challenging for surgical access and treatment. Strategies include both endoscopic and microsurgical approaches.2 A cranio-orbital approach with extradural clinoidectomy and optic canal unroofing provides the necessary corridor to visualize and decompress the optic nerve/chiasm and remains an important tool in achieving complete tumor resection with favorable functional and visual outcomes.3-12 Endoscope assistance in transcranial surgery is well established, used to provide direct visualization of hidden adjacent tissues.13 A 25-year-old woman presented with headache and progressive visual loss to blindness (hand waving and light perception) on admission. Magnetic resonance imaging demonstrated a 28-mm-diameter tumor in the hypothalamic region with no significant postcontrast enhancement. She underwent right cranio-orbital craniotomy, extradural anterior clinoidectomy, and optic canal unroofing with a 2-mm high-speed diamond drill and copious irrigation. After ipsilateral falciform ligament release, the tumor capsule was coagulated, sharply opened, and resected in a piecemeal fashion. Endoscopic assistance warranted the removal of hidden parts and confirmed tumor removal. Histopathology and next-generation sequencing confirmed the diagnosis of rosette-forming glioneural tumor. Follow-up revealed gross total tumor removal on magnetic resonance imaging and complete recovery of visual function as per ophthalmologist examination. Rosette-forming glioneural tumors are considered rare and classified as World Health Organization grade I tumors usually found in the fourth ventricle.14 To our knowledge, we present the first operative video (Video 1) demonstrating the removal of rosette-forming glioneural tumor in the hypothalamic region with endoscopic assistance.

Optic nerve decompression through pterional and supraorbital approaches in the treatment of severe traumatic optic neuropathy

To investigate the effectiveness of optic nerve decompression (OND) in the treatment of severe traumatic optic neuropathy (TON) through pterional and supraorbital approaches, and to identify the prognostic factor for postoperative visual acuity (VA) following OND. Patients with severe TON treated with OND through either pterional or supraorbital approach in our institute from September 2019 to June 2022 were retrospectively reviewed in this study. Demographic information, trauma factors, the interval between trauma and complete blindness, the interval between trauma and surgery, and the associated craniofacial traumas were recorded. Hospitalization days and the postoperative VA of patients in two groups were compared. There were 54 severe TON patients with NLP included in this study; 21 patients underwent OND through the pterional approach, and the other 33 underwent the supraorbital approach. Respectively, in groups of pterional and supraorbital approaches, the average hospitalization days were 9.8 ± 3.2 and 10.7 ± 2.9 days (p = 0.58), the mean durations of follow-up were 18.9 ± 4.3 and 20.8 ± 3.7 months (p = 0.09), and the average circumference of OND were 53.14 ± 15.89 ◦ (range 220 ◦ -278◦) and 181.70 ± 6.56◦ (range 173 ◦ -193◦) (p<0.001). The overall improvement rates of pterional and supraorbital approaches are 57.1% and 45.5% (p = 0.40), respectively. Optic canal fracture (OCF) was revealed to be significantly associated with postoperative VA in the supraorbital approach (Binary: p = 0.014, CI: 1.573-57.087; Ordinal: p = 0.003, CI: 1.517-5.503), but not in the pterional approach. In the group of supraorbital approach, patients with OFC had a higher rate of a better outcome (78.6%) than those without (21.4%). Patients with severe traumatic TON may benefit from OND through either the pterional or supraorbital approach. OCF is a potential prognostic factor for postoperative VA following OND through the supraorbital approach.

Managing intraoperative rupture of internal carotid pseudoaneurysms during endoscopic transnasal optic canal decompression: a case report

Background

Endoscopic transnasal optic canal decompression is widely used in the treatment of traumatic optic neuropathy (TON) following head and craniofacial trauma. Intraoperative hemorrhage is a catastrophic surgical complication during optic canal decompression.

Case description

We present two cases of patients with TON who suffered unexpected intra-operative massive bleeding during endoscopic transnasal optic canal decompression. After intraoperative hemostasis was achieved, emergent cerebral angiograms demonstrated the formation of internal carotid pseudoaneurysms, which were immediately embolized with coils combined with or without Onyx with balloon assistance. One of these cases was also complicated by a postoperative cerebrospinal fluid leak, which failed to be treated with lumbar drainage but was successfully repaired with endoscopic transnasal surgery.

Conclusion

The intra-operative rupture of ICA pseudoaneurysm is a rare but catastrophic complication in TON patients. Intraoperative massive bleeding indicates rupture of ICA pseudoaneurysm. Postoperative emergency angiography and endovascular therapy should be arranged to evaluate and repair the cerebral vascular injury. Endoscopic trans-nasal surgery repairing CSF leaks resistant to lumbar drainage could be efficient and safe following pseudoaneurysm embolization.

Spheno-Orbital Meningiomas: The Rationale behind the Decision-Making Process of Treatment Strategy

Surgery stands as the primary treatment for spheno-orbital meningiomas, following a symptoms-oriented approach. We discussed the decision-making process behind surgical strategies through a review of medical records from 80 patients who underwent surgical resection at the University of Naples Federico II. Different surgical approaches were employed based on the tumor's location relative to the optic nerve's long axis, categorized into lateral (type I), medial (type II), and diffuse (type III). We examined clinical, neuroradiological, surgical, pathological, and outcome factors. Proptosis emerged as the most frequent symptom (97%), followed by visual impairment (59%) and ocular motility issues (35%). Type I represented 20%, type II 43%, and type III 17%. Growth primarily affected the optic canal (74%), superior orbital fissure (65%), anterior clinoid (60%), and orbital apex (59%). The resection outcomes varied, with Simpson grades I and II achieved in all type I cases, 67.5% of type II, and 18% of type III. Recurrence rates were highest in type II (41.8%) and type III (59%). Improvement was notable in proptosis (68%) and visual function (51%, predominantly type I). Surgery for spheno-orbital meningiomas should be tailored to each patient, considering individual characteristics and tumor features to improve quality of life by addressing primary symptoms like proptosis and visual deficits.

Anatomical Study and Clinical Application of Optic Canal Decompression Via Transethmoid-sphenoid Approach Under Endoscope

This study aimed to evaluate the safety and accuracy of the endoscopic transethmoid-sphenoid approach for optic canal decompression. Twelve sides of 6 adult cadaveric heads fixed in formalin were selected to simulate optic canal decompression using the endoscopic transethmoid-sphenoid approach. Furthermore, this approach was used for optic canal decompression in 10 patients (11 eyes) with optic nerve canal injury. Related anatomical structures were observed using a 0-degree endoscope, and the anatomical characteristics as well as the surgical data were collected. The maximum effective widths of the cranial opening, orbital opening, and middle segment of the canal that could be drilled open endoscopically were 7.82±2.63, 8.05±2.77, and 6.92±2.01 mm, respectively. The angle between the line linking the center point of the tubercular recess with the midpoint of the cranial opening of the optic canal and the horizontal coordinate was 17.23±1.34 degrees. At the orbital opening of the optic canal, the ophthalmic artery was located directly inferior to the optic nerve in 2 cases (16.7%) and laterally inferior to the optic nerve in 10 cases (83.3%). Six of the operational eyes were effective while the remaining 5 were ineffective. No postoperative complications such as bleeding, infection, or cerebrospinal fluid leakage were observed during the follow-up period (6-12 mo). In conclusion, optic canal decompression positively impacts the prognosis of partial traumatic optic neuropathy. Furthermore, the endoscopic transethmoid-sphenoid approach for optic canal decompression is a minimally invasive procedure that provides direct access and adequate decompression. This technique is easy to master and suitable for clinical applications.

Endoscopic endonasal optic nerve decompression: treatment of fibrous dysplasia in a pediatric population

OBJECTIVE

Patients with fibrous dysplasia (FD) of the anterior skull base can experience progressive visual loss and impairment. The authors reviewed their experience with endonasal decompression of the optic nerve (ON) in this patient population. Endoscopic ON decompression (EOND) is a feasible surgical approach for children with FD and visual deficit due to structural ON compression.

METHODS

Electronic medical records of children between 1 and 17 years of age with unilateral FD of the anterior skull base and concomitant ON compression, who required EOND between 2017 and 2022 (n = 4), were reviewed for demographic data, both pre- and postoperative imaging, and evaluations by an otolaryngologist, neurosurgeon, and ophthalmologist in a multidisciplinary fashion.

RESULTS

EOND was found to be a safe and effective surgery for children with FD. Visual acuity was stable in 80% of the eyes postoperatively. Visual fields improved in 40% of the eyes and remained stable in the rest.

CONCLUSIONS

EOND is beneficial for progressive optic neuropathy that is unresponsive to steroid therapy and can prevent permanent disability if performed prior to irreversible damage to the nerve. EOND can decompress the edematous ON with proper exposure of the optic canal and orbital apex, without any major complications.

Endoscopic Endonasal versus Transcranial Optic Canal Decompression: A Morphometric, Cadaveric Study

Introduction Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy.

Methods Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally.

Results The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12–15 mm) and 12.4 mm (range 10–16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205–280 degrees) and 124.6 degrees (range 100–163 degrees), respectively.

Conclusion The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort.

Predictors for Surgeries With the Endoscope-Navigation System for Traumatic Optic Neuropathy and its Clinical Assessment

BACKGROUND

To assess surgeries with the endoscope-navigation system (ENS) in patients who underwent traumatic optic neuropathy (TON) and find predictors for best corrected visual acuity (BCVA) outcomes.

METHODS

The clinical data of 96 consecutive TON patients (96 eyes) who underwent decompression surgery with ENS in the Department of Ophthalmology, Shanghai Ninth People's Hospital, from January 2013 to December 2019 were retrospectively reviewed and analyzed. A binary logistic regression was performed to establish a predictive model for BCVA after treatment as TON outcome.

RESULTS

By practicing ENS, 49/96 (51.0%) TON patients got improvement in BCVA, whereas the improvement rate of patients with BCVA of light perception or better was 72.5% (29/40). Hemorrhage within the postethmoid and/or sphenoid sinus, orbital fracture, time interval between trauma and treatment, and BCVA before treatment were predictors for BCVA improvement in TON patients by practicing ENS surgery. The area under raw current curves of the predictive model was 0.826.

CONCLUSIONS

Surgeries with the ENS showed positive outcomes for TON patients, especially for those with better BCVA before treatment, shorter time interval between trauma and treatment, without orbital fracture or hemorrhage within the postethmoid and/or sphenoid sinus.

[Transcranial microsurgical decompression of the optic canal in surgical treatment of meningiomas of the sellar region]

RATIONALE

When removing the meningiomas of the sellar region, there is always a risk of visual impairment for various reasons, in particular, as a result of traction damage to the optic nerve. Decompression of the optic canal increases nerve mobility during tumor manipulation. In cases of meningioma growing into the canal, its decompression often seems necessary.

AIM

Evaluation of the effectiveness and risks of performing decompression of the optic canal.

MATERIALS AND METHODS

The study included patients with meningiomas of the parasellar location, who underwent surgical treatment at the Burdenko Neurosurgical Center for the period from 2001 to 2017. They were divided into two groups - main and control. The main group consisted of 129 patients who underwent decompression of the optic nerve canals when the tumor was removed. The tumor matrix in this group was most often located in the region of the tuberum sellae, supradiaphragmally, in the region of the anterior clinoid process and the optic canal. In 31 cases, decompression was bilateral - during one operation and using one access in 27 patients; in 4 cases, the decompression of the second canal was delayed for 1.5-3 months after the first operation. 160 decompressions were performed by the intradural and 7 - by extradural methods. During intradural decompression, the roof of the optic canal was resected, and during extradural decompression, the lateral wall of the canal was trephined. The control group consisted of 308 patients who did not undergo canal decompression when the tumor was removed. It included meningiomas with a predominant location of the matrix in the area of the tuberclum and diaphragm of the sella. Tumors in both groups were removed according to the same principles (matrix coagulation, mainly the gradual removal of the tumor, the use of ultrasonic aspirator, a situational decision on the radicality of the operation, etc.). The main difference between operations in these two groups was only canal related algorithms (with or without its trepanation), as well as the probable prevalence of significant lateral tumor growth in cases with canal trepanation. Visual functions in the «primary» group were evaluated before and after operations with trepanation of the canal depending on various factors - the initial state of vision and the radicality of the tumor excision, including removal from the canal. The differences in the postoperative dynamics of vision in the main and control groups were studied. The primary data processing was carried out using the program MSExcel. Secondary statistical processing was carried out using the program Statistica. To assess the statistical significance of differences in the results obtained in the compared patient groups, the Chi-square test was used, and in the case of small groups - the exact Fisher test was applied.

RESULTS

In the main group postoperative vision improvement of varying degrees on the side of trepanation was registered in 36.9% (59 out of 160) cases, no vision changes were found in 36.9% (59 out of 160), and in 26,2% (42 out of 160) the eyesight deteriorated. If preserving vision is attributed to a satisfactory result, then in general the results of these operations should be considered good. A comparative study of the results of removal of meningiomas with trepanation of the canals (main group) or without it (control group) was carried out among patients with the most critical vision situation (visual acuity 0.1 and below, up to only light perception). These groups are comparable in the number of observations - 62 and 73 respectively. The predominance of cases with improved vision in the main group compared with the control group (50.0% versus 38.36%) and a lower incidence of vision impairment (22.58% versus 34.25%) were found. However, the revealed differences are statistically unreliable and make it possible for us to talk only about the trend. The complications associated with trepanation of the canal include mechanical damage to the nerve by the drill. In our series of observations, there was only 1 case of abrasion of the nerve surface with the burr, which did not lead to a significant visual impairment. With the intradural method of trepanation in the area of the medial wall of the canal, the sphenoid sinus may open (in our series, in 34 cases out of 160 trepanations). Immediately closure of these defects was performed by various auto- and allomaterials in various combinations (pericranium, fascia, muscle fragment, hemostatic materials, and fibrin-thrombin glue). A true complication - CSF rhinorrhea liquorrhea developed in only one case, which required transnasal plastic surgery of the CSF fistula using a mucoperiostal flap.

CONCLUSIONS

1. Trepanation of the optic canal in cases of meningiomas of parasellar localization is a relatively safe procedure in the hands of a trained neurosurgeon and does not worsen the results of operations compared with the excision of the same tumors without trepanation of the canal. 2. The literature data and the results of our study make it possible to consider the decompression of the optic canal as an optional, but in many cases, useful option that facilitates the transcranial removal of some meningiomas of the sellar region.

Outcome of the surgical decompression for traumatic optic neuropathy: a systematic review and meta-analysis

There exists a persisting controversy regarding the indications for optic nerve surgical decompression (ONSD) in traumatic optic neuropathy (TON). A meta-analysis is warranted to help guiding therapeutic decisions and address gaps in knowledge. The authors conducted a search of PubMed and MEDLINE electronic databases. Primary endpoint was the improvement in the visual function with ONSD in comparison with the conservative management. Secondary endpoint was visual function improvement when surgery was performed within the first 7 days. A random effects model meta-analysis was conducted. Data from each study were used to generate log odds ratio and 95% confidence intervals, to compare post-operative visual improvement. Nine studies met the inclusion criteria for analysis, comprising 766 patients. Visual improvement occurred in 55% (198/360) of patients treated with ONSD, and in 40% (164/406) of those who underwent conservative treatment. Forest plot revealed significant differences in the visual function improvement among these two groups, although further analysis revealed the studies were heterogeneous (log OR, 0.81; CI, 0.07-1.55; I², 62.8% p = 0.015). Overall, patients who underwent early surgery had better visual outcomes (log OR, 0.94; CI, 0.29-1.60; I², 0% p = 0.9). ONSD is an effective technique to improve the outcome in the visual function in patients with TON. A lack of randomized controlled trial-and inherent surgical selection and publication bias-limits direct comparison between surgical decompression and conservative management. Suitably designed prospective cohort studies may be useful in identifying patients more likely to receive benefit from ONSD.

Bilateral endoscopic optic nerve decompression in an infant with osteopetrosis

Osteopetrosis is a rare disorder of bone remodeling characterized by defective resorption leading to excessive skeletal mass including optic canal. Compression of the optic nerve from the narrowed optic canal is the most common cause of vision loss in children with osteopetrosis. We report the case of a 6-month old girl with osteopetrosis who underwent bilateral optic canal decompression via endoscopic transcaruncular approach for progressive deterioration of visual function secondary to compressive optic neuropathy from narrowed optic canals. The patient showed improvement in visual function postoperatively.