Minimally invasive resection of a spheno-orbital tumor: Review of surgical techniques and a case report

Abstract

Background:

Resection of neoplasms of the cranio-orbital region represents a significant surgical challenge due to the extensive spread of the tumor into adjacent anatomical structures, deep regions of the skull base, the dense structure of the tumor, and the complexity of defect reconstruction. The aim of this study is to present a minimally invasive approach, using the example of a spheno-orbital tumor, to evaluate its effectiveness and cosmetic advantages.

Case Description:

A 46-year-old patient with a spheno-orbital cranial neoplasm presented with exophthalmos and decreased visual acuity (VA 6/18), which had been present for approximately 6 years. A diagnostic evaluation revealed a tumor involving the left greater wing of the sphenoid bone, with extension into the orbit and skull base structures. A notable feature on computed tomography imaging was the inward protrusion of the inner surface of the hyperostotic bone, the lesion had well-defined irregular contours, with remodeling. The patient underwent tumor resection with orbital decompression using a minimally invasive technique. The postoperative period was uneventful, and VA improved on the 1^st postoperative day. The patient was followed for 18 months postoperatively, during which no evidence of residual tumor growth was observed.

Conclusion:

The presented minimally invasive lateral spheno-orbital approach proved to be safe and cosmetically favorable due to the small incision within the hair-bearing scalp and preservation of the orbital rim. This approach demonstrated good effectiveness in orbital decompression and may be used as a first-stage procedure when a symptom-oriented strategy is sufficient before craniotomy.

INTRODUCTION

Neoplasms of the spheno-orbital region constitute a large group depending on their localization and histological origin. These include spheno-orbital meningioma, frontal bone hyperostosis, osteoma, focal erythroid hyperplasia, fibrous dysplasia, and osteoblastoma.[16,22] A differential diagnosis should be performed among these tumors.[10]

The clinical presentation is characterized by the simultaneous occurrence of neurological and ophthalmological symptoms, as well as cosmetic deformity. This is due to the involvement of multiple bones of the skull and orbit, as well as the midfacial skeleton. Exophthalmos, decreased visual acuity (VA), and ophthalmoparesis are the most common symptoms and represent the main indications for surgical treatment.[7,15,17] Since quality of life is closely associated with VA and cosmetic outcomes, this underscores the importance of optimizing surgical approaches to improve visual function.[19]

Resection of tumors of the spheno-orbital region is associated with two major challenges, as described by Mirone et al.[23] First, there is extensive tumor spread into adjacent structures, including the paranasal sinuses, cavernous sinus, anatomical fissures, and foramina of the skull base. Second, these tumors often have a dense, bony consistency.

In this clinical case, we present our experience in the application of minimally traumatic surgical techniques aimed at addressing the challenges described above, without compromising patients’ quality of life or cosmetic outcomes.

CASE DESCRIPTION

In April 2024, a 44-year-old patient was admitted with complaints of pain and blurred vision in the left eye, bulging of the eye, and uneven appearance of the eyes causing a noticeable cosmetic deformity. According to the patient, these symptoms had been present for approximately 6 years. The patient initially consulted an ophthalmologist, who recommended magnetic resonance imaging (MRI). Imaging revealed a sphenoid wing tumor with extension into the orbit. Afterward, the patient presented with the above-mentioned complaints to the republican specialized scientific and practical medical center of neurosurgery and was admitted for further evaluation and management.

Neurological examination revealed a significant decrease in VA on the left side (OS–0.3), exophthalmos, and limitation of eyeball mobility due to tumor compression (not ophthalmoparesis). Pupils were equal in size (D = S), and the pupillary light reflex was preserved. No clinical or neurological signs of adenohypophyseal dysfunction were observed.

Neuro-ophthalmological examination: VA OD 6/6 and OS 6/18, with no gaze paresis. OS exophthalmos measured 7 mm [Figure 1a-c]. Perimetry demonstrated concentric visual field constriction of 15–20°. Fundoscopic examination showed partial descending optic nerve atrophy in the left eye.

Figure 1:

(a-b) Computed tomography (CT) “bone window:” The optic nerve is compressed against the anterior portion of the optic canal due to lateral compression by the tumor. Meanwhile, the optic canal itself is not narrowed and remains within normal limits. (c) CT demonstrated marked unilateral right-sided exophthalmos (≈7 mm), corresponding to grade III proptosis.

Computed tomography (CT) scans revealed a tumor of the greater wing of the left sphenoid bone, the lateral wall of the left orbit, and the lateral wall of the left sphenoid bone; a mass lesion measuring 5.1 × 6.7 × 4.2 cm is visualized. The lesion has well-defined irregular contours, with remodeling, and a density of +814 ± 134 Hounsfield units, with extension into the optic canal causing compression of the left optic nerve [Figure 2a-c].

Figure 2:

(a-c) Preoperative computed tomography of the brain and orbits (bone window + 3D reconstruction). A hyperdense spheno-orbital tumor with extension into the orbit, causing compression of the globe and neuromuscular structures. Left-sided exophthalmos is present. The red circles in “c” indicate the intraorbital extension of the spheno-orbital tumor.

MRI scans revealed a large well-defined sclerotic mass on both T1 and T2 sequences in the left sphenoid wing, with extension into the lateral orbital wall and optic canal, resulting in compression of the left optic nerve and displacement of intraorbital contents. The lesion results in exophthalmos [Figure 3a-d].

Figure 3:

(a-d) Preoperative magnetic resonance imaging of the brain and orbits. A hypointense spheno-orbital mass lesion is visualized. The tumor compresses the globe and the intraorbital portion of the optic nerve toward the medial wall of the orbit. Exophthalmos is also noted.

The homogeneous structure of the tumor, well-defined margins, and slow growth over 6 years suggested a benign process. Considering the dense bony consistency, deep location of the lesion, and absence of neurological symptoms related to involvement of adjacent structures, total resection was not planned. The goal of surgery was resection of the bony tumor involving the orbital wall and the greater wing of the sphenoid bone, with orbital decompression. Differential diagnosis was performed to distinguish it from fibrous dysplasia and osteoma.

Proposed surgical technique

Conventionally, various cranial surgical approaches (pterional and orbitozygomatic craniotomy) or orbitotomies (lateral orbitotomy and modified lateral orbitotomy) have been used for the removal of such tumors.[1,18] We have not come across this proposed approach in the available literature. Based on its topographic-anatomical location, we suggest referring to it as the mini-invasive lateral spheno-orbital approach.

Intraoperative course

The patient is positioned on the operating table in the supine position, with the head rigidly fixed, rotated approximately 30° toward the healthy side, and elevated about 15° above the level of the chest. The occiput is slightly tilted downward, and the chin upward [Figure 4a]. Before the skin and soft-tissue incision, the course of the superficial temporal artery (STA) and the frontal branch of the facial nerve (TFN) are identified. Standard anatomical landmarks and Pitanguy’s line [Figure 4b] are used to identify these structures. In addition, ultrasound is useful for identifying the STA. The incision is made within the aforementioned safe zone between the STA and TFN according to the described scheme in the frontotemporal region. It begins anterior to the tragus at the level of the superior border of the zygomatic arch and continues upward and forward toward the frontal region up to the superior temporal line [Figure 1a].

Figure 4:

(a) Patient positioning and skin incision. (b) The topography of the facial nerve and superficial temporal artery and methods for their identification. STA - Superficial Temporal Artery; FSTA - Frontal branch of the Superficial Temporal Artery; TFN - Temporal branch of Facial Nerve; SOM- Superior Orbital Margin; LOM - Lateral Orbital Margin; H - Helix. The numbers are distance in millimeters (mm) used as surface anatomical landmarks to help identify the course of the important structures such as STA, TFN and to plan a safe skin incision. 25mm - 2.5cm anterior to the superior root of the helix (H) at the level of the lateral canthus. 40mm - 4cm posterior to the lateral orbital margin (LOM) at the level of the lateral canthus. 45mm - 4.5cm posterior to the LOM at the level of the supraorbital margin (SOM). 60mm - 6cm posterior to the LOM at the level of the lateral canthus.

Interfascial dissection is performed, keeping the skin in contact with the superficial layer of the fascia to minimize the risk of injury to the TFN. The raised skin flap is reflected toward the zygomatic process of the frontal bone and the zygomatic arch, followed by resection of the temporalis muscle. The temporal fossa, the temporal surface, the angular junction of the greater wing, the posterior surface of the posterolateral orbital wall, and partially the lateral orbital rim are skeletonized. A bony neoplasm of the greater wing of the sphenoid bone extending into the orbital cavity is identified. Resection and osteotomy of the orbital portion of the tumor are then initiated in the region of the sphenozygomatic suture [Figure 5a and b], with preservation of the lateral wall of the orbital rim. This made it possible to avoid reconstruction and ensured a good cosmetic result.

Figure 5:

(a and b) The direction of the surgical corridor after dissection of the temporalis muscle. Three-dimensional CT reconstruction showing the sphenozygomatic suture (arrow/oval) at the lateral orbital wall.

Access to the orbit was achieved through the temporal fossa. During removal of the sphenoidal portion of the tumor, the osteotomy window was enlarged posterior to the zygomatic process of the frontal bone, extending inferiorly by cutting the orbitocranial angle of the greater wing of the sphenoid bone. After this, intracranial resection of the hyperostotic, altered bone tissue of the greater wing, and the posterior orbital portion of the tumor was continued until satisfactory decompression of the eyeball [Figure 6a-c] and, if necessary, of the optic nerve was achieved. The intraorbital fatty tissue was preserved to maintain orbital volume and prevent enophthalmos. The size of the trephination window was small (2.7 × 3.9 cm); therefore, cranioplasty of the defect was not performed [Figure 6d and e]. A counter-aperture drainage tube was left in place and removed the following day. The muscles and the skin–aponeurotic flap were closed in layers.

Figure 6:

(a-e) Postoperative computed tomography of the brain with 3D reconstruction. Subtotal tumor resection was achieved, with the expected degree of decompression. The lateral portion of the orbital rim was preserved.

Histopathological examination confirmed meningioma [Figure 7].

Figure 7:

Staining: hematoxylin and eosin. Magnification: 10 × 10. Microscopic description: Morphologically, a tumor composed of oval and spindle-shaped cells with nuclear polymorphism is identified, arranged in syncytial and fibrous areas, with the presence of characteristic whorled structures. No signs of malignancy, mitotic activity, or necrosis are observed.

Microscopic description

Morphologically, a tumor composed of oval and spindle-shaped cells with nuclear polymorphism is identified, arranged in syncytial and fibrous areas, with the presence of characteristic whorled structures. No signs of malignancy, mitotic activity, or necrosis are observed.

On the 1^st postoperative day, VA in the left eye recovered to VA OU 0.9. On the 4^th postoperative day, after resolution of soft-tissue edema, exophthalmos and dystopia showed visible regression. Three months after surgery, exophthalmos had almost completely resolved, and the cosmetic outcome was excellent. Visual fields and the range of ocular movements also recovered, and no severe complications were observed.

During an 18-month follow-up period, no progression of the residual tumor or recurrence of symptoms was noted.

DISCUSSION

In the present case, resection of a spheno-orbital meningioma was performed using a minimally invasive spheno-orbital approach, which provided adequate decompression of the orbit, the optic nerve (intraorbital), and the extraocular muscles. In recent years, particular attention has been focused on decompression of the lateral orbital wall and the optic nerve to reduce exophthalmos,[14] and balanced orbital decompression in orbitocranial pathologies is a generally accepted concept.[14,22] In our study, total tumor removal was also not considered due to invasive tumor growth into the skull base bone and its dense consistency. The primary goals were reduction of exophthalmos and restoration of vision through decompression without cosmetic defects, which is supported by the results of the meta-analysis by Agosti et al.[2] Accordingly, a symptom-oriented approach was adopted, as radical resection is not recommended due to the high risk of perioperative complications.[25] In the literature and in clinical practice, we observe that total removal of a tumor does not, in all cases, ensure a favorable outcome with respect to recurrence and malignant transformation. In their work, Sandalcioglu et al. report that in six out of 11 cases, in which total tumor resection was performed, tumor recurrence was detected. At the same time, in three out of five patients, despite incomplete resection, no continued tumor growth was observed.[26]

At present, numerous surgical approaches have been developed to access tumors of cranio-orbital and orbital localization. The choice of surgical approach is determined by the need for minimal invasiveness, the shortest and most direct route to the pathological focus, and achievement of a favorable esthetic outcome. Superior transcranial approaches are preferred in the presence of intracranial tumors extending into the medial compartments of the orbit.[20] In cases of tumor invasion into the cranial cavity and the medial pterional region, transcranial approaches are indicated, including the fronto-orbito-temporal approach with or without orbitozygomatic osteotomy,[1,22] the pterional approach,[12,28] and the transzygomatic approach.[16,23] According to the reviewed literature, the most commonly used surgical technique is pterional craniotomy, with or without removal of the orbital wall, anterior clinoid process, and optic canal.[4,8,11,21] There is also strong evidence supporting the effectiveness of the pterional approach, as it allows access to the middle cranial fossa, anterior cranial fossa, and orbit through a single approach.[2] However, Fisher et al. reported a high rate of complications associated with the pterional approach, with a 95% confidence interval indicating high precision of the results. The most frequent complications were cranial nerve deficits (23%), followed by ophthalmoplegia (20%), diplopia and ptosis (17% each), and hypesthesia of the trigeminal nerve (CN V) in 15% of cases. Notably, deterioration of VA was observed in only 5% of cases.[12]

Lateral bony orbitotomy is also widely used in the surgery of spheno-orbital neoplasms. This approach was first described by Krönlein for the surgical treatment of orbital tumors and has undergone multiple modifications over time. Lateral orbitotomy provides wide exposure of the orbital contents and allows effective access to the superolateral orbital compartment.[21,24] However, it has limitations in accessing the cranial component of the tumor[17] and is often associated with periorbital scarring and difficulties in restoring the normal anatomical contours of the orbit.[7,20] Amirjamshidi et al.[3] conducted a large study including 88 patients with spheno-orbital meningioma. Standard pterional craniotomy was performed in 12 patients, while 76 patients underwent lateral mini-orbitotomy. The authors modified the Berke incision by extending it in a curved fashion toward the eyebrow.[3] In contrast to lateral orbitotomy, in our technique, the incision was made within the hair-bearing scalp, and the lateral orbital rim was preserved to avoid facial scarring and displacement of orbital bone fragments.

Minimally invasive endoscopic approaches are also well described and offered favorable cosmetic outcomes. For example, the endonasal endoscopic approach is effective for medial decompression of the optic canal, whereas the endoscopic transorbital approach is used for lateral lesions to decompress hypertrophied bone and remove tumor tissue, aiming to achieve optimal cosmetic results.[6,9] However, when endoscopic approaches are used, the rate of radical resection remains relatively low (23.5%), despite a high rate of improvement in exophthalmos (79.4%).[2]

The technique we propose resembles a pterional craniotomy but differs in its simplicity and minimally invasive nature. Due to the small cosmetic incision and preservation of the lateral orbital rim, this approach was defined as minimally invasive. The target area is the projection of the sphenozygomatic suture (rather than the pterion), and the osteotomy is performed below the pterional point, without the need to create a wide craniotomy window. The lateral trajectory through the temporal fossa allows avoidance of injury to the frontal sinus and the superior orbital wall, thereby eliminating the risk of orbital emphysema and infectious complications. Preservation of the frontal branch of TFN eliminates the risk of postoperative ptosis. An extradural approach to the cranial cavity is used, where the dura mater is most distant from the skull bone, which enhances the safety of the procedure. This approach provides a short and direct surgical corridor to the lateral, superolateral, and inferolateral compartments of the orbit, with the possibility of extension toward the greater wing of the sphenoid bone and the retrobulbar space. The proposed technique allows intraoperative adjustment of the extent of resection depending on tumor spread, ensuring high cosmetic effectiveness with minimal surgical trauma.

Another major dilemma is the question of orbital reconstruction and the prevention of enophthalmos. According to Gaillard et al., orbital reconstruction should be performed only in cases when more than one orbital wall has been removed.[13] At the same time, Shrivastava et al. emphasize the necessity of bony orbital reconstruction, when indicated, with the possible use of alloplastic materials to prevent complications such as meningocele, diplopia, and pulsatile enophthalmos.[27]

This procedure is applicable for spheno-orbital meningiomas and tumors of the lateral orbital compartment with extension into the optic canal, superior orbital fissure, and the greater wing of the sphenoid bone. It may also be used for isolated orbital tumors. However, in tumors with predominantly medial localization, involving the paranasal sinuses and extending to the cavernous sinus and adjacent skull base structures, this approach is not indicated, and an orbitozygomatic approach or other lateral skull base approaches should be considered.[17,22]

Role of modern technologies and future perspectives

We believe that the use of modern technologies can further improve the safety and effectiveness of the proposed minimally invasive approach. In particular, neuronavigation systems enhance the surgeon’s spatial orientation during bone resection in anatomically critical areas, allowing more accurate delineation of resection margins. This may subsequently increase the radicality of the procedure while reducing the risk of complications.[5,9] The use of ultrasonic bone aspirators may provide more controlled resection of dense bony tissue, as tumor density represents one of the main challenges in surgery of this region.[23] Intraoperative CT may also be effective for objective assessment of the adequacy of orbital decompression before completion of the surgical procedure.

Study limitations

The present study has several limitations. First, it represents a single case report, which precludes statistical analysis, limits the generalizability of the results, and does not allow direct comparison of the proposed technique with other surgical approaches due to the absence of a control group. Although stable clinical and radiological outcomes were observed during an 18-month follow-up period, longer-term dynamic observation is advisable for slowly growing neoplasms (up to 6 years of growth).

CONCLUSION

Spheno-orbital meningioma is a slow-growing skull base tumor characterized by the development of exophthalmos and decreased VA. The presented clinical case demonstrates the feasibility of a symptom-oriented minimally invasive approach through the temporal fossa for spheno-orbital neoplasms with bony invasion. The use of this approach allowed adequate orbital decompression with restoration of visual function and complete regression of exophthalmos, while preserving the lateral orbital rim and avoiding significant cosmetic defects. It should be emphasized when the primary surgical goals are preservation of visual function and improvement of cosmetic outcome.

Ethical approval:

The research/study approved by the Institutional Review Board at Republican Specialized Scientific and Practical Medical Center of Neurosurgery, number 08-11/450, dated November 12, 2025.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given consent for their images and other clinical information to be reported in the journal. The patient understands that the patient’s names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI

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