Transfacial access for neurosurgical procedures: an extended role for the maxillofacial surgeon. II. Middle cranial fossa, infratemporal fossa and pterygoid space

Surgery for maxillary oral squamous cell carcinoma: the effect of surgical resection margins and elective neck dissection on oncological outcomes

Maxillary oral squamous cell carcinoma (OSCC) is uncommon. Surgical resection is challenging due to the anatomy, and the role of elective neck dissection (END) is not well-defined. A retrospective cohort study of patients with maxillary OSCC treated with primary surgery between 2007 and 2019 was conducted. Primary tumours of sinonasal origin with extension into the oral cavity were excluded. Survival analysis was performed using Kaplan-Meier and Cox proportional hazards models. Sixty-seven patients were included; mean follow-up was 55 months. On univariate analysis, clear (≥5 mm) margins were associated with higher disease-free (68% vs 36%, P = 0.019) and overall survival (75% vs 36%, P = 0.004) than close/involved (<5 mm) margins. In clinically node-negative patients, the risk of occult cervical metastasis in tumours with depth of invasion (DOI) ≥ 3 mm and T2-4 tumours was 22% and 25%, respectively. END in these groups was associated with a lower rate of loco-regional recurrence (DOI ≥3 mm subgroup: 5% vs 38%, P = 0.029; T2-4 subgroup: 6% vs 50%, P = 0.028) and longer time to recurrence (DOI ≥3 mm subgroup: 119 months vs 96 months, P = 0.042; T2-4 subgroup: 117 months vs 56 months, P = 0.031) than observation of the neck. On multivariate analysis, close/involved margins were associated with an increased risk of overall mortality (hazard ratio 3.4, 95% confidence interval 1.0-11.3, P = 0.043) and disease recurrence (hazard ratio 2.8, 95% confidence interval 1.1-7.1, P = 0.031). In maxillary OSCC, a ≥ 5 mm histological margin should remain the goal of ablative surgery. END should be considered in tumours with DOI ≥ 3 mm.

Transfacial Exposures of the Anterior Skull Base and Cervical Spine: Straightforward "Line-of-Sight" Algorithm for Selection of Approach

ABSTRACT

Surgical treatment for tumors of the skull base remains gross total resection with microscopic negative margins. Sufficient surgical access is paramount to adequate treatment but must be balanced with patient morbidity and protection of vital neurovascular structures. While endoscopic surgery has made transfacial access less common, there are still indications for open transfacial exposure including tumors that involve facial soft tissues, the palate, anterolateral frontal sinus, dural involvement lateral to the mid-pupillary line, tumor recurrence/repeat resection, and/or lack of access to endoscopic equipment or expertise. The authors present a "line-of-sight" algorithm for selection of approach, discuss pre-operative planning, review selected clinical experiences, and discuss the role of microsurgery and prevention of complications.

Endoscopic transoral and transmaxillary excision of the infratemporal fossa hemangioma

Hemangiomas in the infratemporal fossa (ITF) are extremely rare benign vascular tumors. For many tumors of the ITF, with the exception of some small hemangiomas, a lateral facial approach has often been required. Recently, however, there have been some reports that minimally invasive endoscopic surgery can be used in the ITF; this would reduce the risk of surgical complications. To date, there has been no report of a hemangioma of the ITF exceeding 6 cm being resected by the endoscopic approach without facial incisions. Here, however, we report two cases of ITF hemangiomas that were completely extracted endoscopically, using a transmaxillary and transoral approach, without facial incisions or surgical complications.

Skull base tumors: a kaleidoscope of challenge

Resection of skull base lesions has always been riddled with problems like inadequate access, proximity to major vessels, dural tears, cranial nerve damage, and infection. Understanding the modular concept of the facial skeleton has led to the development of transfacial swing osteotomies that facilitates resection in a difficult area with minimal morbidity and excellent cosmetic results. In spite of the current trend toward endonasal endoscopic management of skull base tumors, our series presents nine cases of diverse extensive skull base lesions, 33% of which were recurrent. These cases were approached through different transfacial swing osteotomies through the mandible, a midfacial swing, or a zygomaticotemporal osteotomy as dictated by the three-dimensional spatial location of the lesion, and its extent and proximity to vital structures. Access osteotomies ensured complete removal and good results through the most direct and safe route and good vascular control. This reiterated the fact that transfacial approaches still hold a special place in the management of extensive skull base lesions.

Access to the skull base: modular facial disassembly

Access to the skull base is not new. The different modules of the facial skeleton can be removed to give access to the skull base based on target zones, which were first described by Grime et al in 1991. However, the vertical plane is not considered, and this article adds to the original classification and develops a decision-making algorithm for preferred access to identified lesions of the skull base.

Clear cell calcifying epithelial odontogenic (Pindborg) tumor involving the maxillary sinus: A case report and review of literature

Calcifying epithelial odontogenic tumor (CEOT) is a rare benign odontogenic neoplasm of the jaws, accounting for less than 3% of all odontogenic tumors. It rarely extends into the maxillary sinus. Till date, six cases involving maxillary sinus have been reported. In this paper, we report the seventh case of a 52-year-old male with CEOT in maxilla extending from distal surface of the right maxillary canine to retromolar area and involving maxillary sinus with no association with impacted teeth. The diagnosis was confirmed by aspiration cytology and histologically, the tumor was composed of sheets of epithelial cells, with areas of clear cell changes. The presence of clear cells in the histological sections, accounts for the aggressive nature of the tumor simulating the clinical appearance. Prevention of recurrence can be achieved by radical resection.

Access osteotomy for infratemporal tumors: Two case reports

Tumors occurring in the infratemporal region present a surgical challenge and access osteotomies of the facial skeleton is the answer to access these deeply situated, inaccessible tumors of the head and neck. Various approaches have been devised for their better exposure and it is our expertise as maxillofacial surgeons to provide surgical access by transmaxillary, transzygomatic and transmandibular approaches. We followed this concept in our institute and report here two case reports. The first is a 45-year-old female who presented with right facial pain and temporal swelling due to schwannoma in the right infratemporal region extending into middle cranial fossa. This was jointly treated by a team of neurosurgeons, maxillofacial surgeons and ENT surgeons by right temporal craniotomy, right transmandibular and transzygomatic approach. The second is a rare tumor occurring in a 26-year-old male with the chief complaint of right frontal headache and diplopia. The tumor was excised via access through the zygomatic arch and lateral orbital wall; diagnosed later as Rosai Dorfmans disease. No recurrence was seen at follow-up period of 2 years. These approaches help to reduce the surgical morbidity. Thus, oral and maxillofacial surgeons form a vital role in the multidisciplinary approach to provide access to difficult anatomic locations.

Maxillary calcifying epithelial odontogenic (Pindborg) tumor presenting with abnormal eye signs: case report and literature review

Calcifying epithelial odontogenic tumors (CEOT) are uncommon, accounting for less than 1% of all odontogenic tumors. The CEOT, since its description by Pindborg in 1958 as a separate pathologic entity, is commonly known as the Pindborg tumor. We present an unusual case of such a tumor in the maxilla presenting with abnormal eye signs. The case demonstrates the use of a Le Fort I down-fracture osteotomy approach to maxillary tumors.

The open-mouth fronto-orbitotemporozygomatic approach for extensive benign tumors with coexisting splanchnocranial and neurocranial involvement

OBJECTIVE

To describe the advantages of a modification of the standard fronto-orbitotemporozygomatic (FOTZ) approach, consisting of the forced opening of the patient's mouth (open-mouth FOTZ), for the treatment of benign tumors massively involving the splanchnocranium and neurocranium.

METHODS

The modified FOTZ approach obtained by forced mouth opening is described. Such a procedure was introduced with the aim of obtaining a minimally invasive access to lesions involving both the infratemporal-parapharyngeal spaces and the anteromedial cranial fossae. The forced opening of the mouth allows the surgeon to keep the coronoid process of the mandible away from the operating field, producing a wide exposure of the infratemporal space like that of the posterior wall of the maxillary sinus, which can be penetrated from behind without adding destructive procedures on the mandibular bone.

RESULTS

From a series of 45 patients affected by cranial base lesions operated on during an 8-year time period, three patients affected by juvenile nasopharyngeal angiofibromas were selected for an open-mouth FOTZ approach. In all cases, a complete eradication of both the intracranial and extracranial components of the tumor was possible by this approach. The same procedure was then used in four patients affected by extensive meningiomas and two patients harboring Vth cranial nerve schwannomas, with complete tumor removal.

CONCLUSION

In our experience, the open-mouth FOTZ approach seems particularly suited for extensive benign tumors (including juvenile nasopharyngeal angiofibromas) with splanchnocranial and neurocranial involvement. No indication exists for the use of this approach in malignant tumors, in which total eradication with large tumor-free margins is required.

Surgical landmarks of the infratemporal fossa

Surgical interventions on the infratemporal fossa require an accurate knowledge of the surgical anatomy. Thirty-four adult human skulls were examined and measurements made of the distance between the zygomatic arch and the root of the lateral pterygoid plate. The distance between the central part of the lateral and medial pterygoid plates was also measured. The first measurement represents the distance of the foramen ovale from the zygoma; the average being 38.2 mm. The average distance between the pterygoid plates is 9.6 mm. Addition of these two measurements represents the distance of the lateral wall of the nasopharynx from the zygoma and the average is 47.8 mm. Together with the knowledge of the arrangement of the muscle layers and the nerves and vessels in this region, this information has proved useful in the surgery of the area.

The orbitozygomatic infratemporal fossa approach: a quantitative anatomical study

Using detailed cadaveric dissections this study has demonstrated and quantified the increase in exposure and additional access gained by using the orbitozygomatic infratemporal fossa approach for neurosurgical access. The surgical window of exposure can be increased by up to 300% when this technique is utilised to facilitate access via either a subtemporal (to access the P2 segment of the posterior cerebral artery) or transsylvian (to access the basilar bifurcation) approach. In addition the distance between the surgeon and the operative field can be decreased by approximately 2-3 cm. The orbitozygomatic infratemporal fossa approach is a relatively simple technique which can readily increase neurosurgical exposure of the skull base. It also provides simultaneous access to the infratemporal fossa, pterygopalatine fossa and the orbit.

Transpalatine excision of a cavernous hemangioma of the infratemporal fossa

Hemangiomas of the head and neck region can represent a therapeutic challenge depending on their size, location and symptoms. We report a case of a 40-year-old woman who presented with a 2-cm encapsulated cavernous hemangioma in the infratemporal fossa (ITF). Extensive workup included CT, MRI and angiography. A transoral/transpalatine approach avoiding osteotomy was used for surgical excision. After an unremarkable postoperative course the patient has remained disease-free after a 2-year follow-up period. We suggest this surgical approach as an alternative in carefully selected cases of circumscribed small, benign lesions of the ITF.

The transzygomatic approach: a long-term clinical review

The transzygomatic approach has been utilised to improve access to the skull base, infratemporal fossa and orbit for a number of years. It provides a low anterolateral approach to the skull base, along the floor of the middle fossa. It allows both a transsylvian and subtemporal approach with a reduction in brain retraction and better exposure of adjacent neurovasculature structures. A long term review of 53 patients is presented highlighting outcome at two years post surgery and morbidity of the approach. It is concluded that the technique is versatile and can be used to improve exposure of a variety of anatomical locations. There is minimal long term morbidity attributable to the surgery of access and the majority of patients have had good outcomes.