The transbasal approach to the anterior skull base: surgical outcome of a single-centre case series

Abstract

A variety of sinonasal tumours, meningiomas or other lesions of the anterior skull base involve the paranasal sinuses and the periorbital area. The transbasal approach (TBA) has turned out to be a feasible technique to reach those lesions. A retrospective review at a neurosurgical university department between November 2007 and January 2020 with adult patients who underwent resection of oncologic pathologies through TBA. Surgical technique, extent of resection (EOR), clinical outcome and postoperative complications were analysed. 18 TBAs between November 2007 and January 2020 were performed. Median age was 62 (range 25-83), 7 female and 11 male patients. Gross total resection rate was 85.8% throughout all entities. Four (22.2%) patients suffered from WHO°I meningiomas and 14 (77.7%) from other extra-axial lesions. Preoperative Karnofsky Performance Status Scale (KPSS) was 80% (range 40-90), postoperative KPSS 80% (range 20-100). Rate of postoperative complications requiring intervention was 16.7%. Median follow-up was 9.8 (range 1.2-71.8) months. Modifications and extensions of the classic TBA are not mandatory. Complete resection can be performed under functional and cosmetic-preserving aspects. Second-step procedures such as transnasal approaches may be performed to avoid high morbidity of more aggressive TBAs, if necessary. Surgical considerations should be kept simple and straightforward.

Figure 1

Exemplary case 1: a 74-year-old female patient admitted after fall at home and back pain. Cranial routine CT scan displayed a huge transbasal bone infiltrating and destroying a tumor with sinonasal affection. (A,B) Preoperative T1-weighted gadolinium-enhanced MR imaging showing sinonasal and orbit-infiltrating tumor with subtotal anterior skull base destruction. (C,D) Postoperative MR control showing successful resection. Reconstruction was performed with split-bone graft and galea-periosteum flap. Pathologic findings revealed adenoid cystic carcinoma. The patient recovered well from the procedure; she underwent VP-shunt implantation in further course.

Figure 2

Exemplary case 2: a 70-year-old male patient presented with recurrent left eye inflammations and swelling over medial canthus. Ophthalmic examination revealed obstructed nasolacrimal ductus. (A,B) Preoperative T1-weighted gadolinium-enhanced MR imaging showing sinonasal and left orbit-infiltrating tumor. Ethmoidal and sphenoid sinus are completely infiltrating. Left bulbus is suppressed. (C,D) Postoperative MR control showing successful resection. Orbit, sphenoid and tuberculum sellae reconstructions were performed with split-bone graft, galea-periosteum flap and fibrin glue. Pathologic findings revealed metastasis of malign melanoma. The patient underwent endoscopic transnasal, sublabial reresection in the subsequent course.

Figure 3

Exemplary case 3: a 60-year-old female patient with left amaurosis and right progressive visual deficit after two-timed resection of transbasal meningotheliomatous meningioma WHO grade I through a bifrontal craniotomy. (A,B) Preoperative T1-weighted gadolinium-enhanced MR imaging showing frontobasal meningioma with olfactory grove, ethmoidal and sphenoidal sinus and intrasellar affection. (C,D) Postoperative MR control showing Simpson II resection. Extradural clinoidectomy was performed in this case as well. Reconstruction was performed with split-bone graft and galea-periosteum flap. The patient recovered well from the procedure and underwent radiotherapy after multidisciplinary tumor board discussion.

Figure 4

Exemplary case 4: a 78-year-old male patient with bilateral amaurosis, anosmia and psychomotoric disorders. Known sinusinal intestinal adenocarcinoma after endonasal biopsy. Radiotherapy was already carried out. Transnasal microscopic tumor debulking was performed a priori. (A–C) Preoperative T1-weighted gadolinium-enhanced MR imaging showing the huge infiltrating transbasal tumor with right orbital destruction and maxillary sinus affection. Reconstruction was performed with split-bone graft, galea-periosteum flap and collagen-based dura graft. No postoperative CSF leak occurred. (D–F) Postoperative MR control showing subtotal resection. F Small tumor remnant in the right periorbital.

Figure 5

Exemplary case 5: a 64-year-old male patient with anosmia, rhinorrhoea, epiphora and headache. Transnasal biopsy revealed sinusinal intestinal adenocarcinoma. (A,B) Preoperative T1-weighted gadolinium-enhanced MR imaging endonasal tumor with transbasal infiltration into sphenoid sinus, cribriform plate and dislocation of right periorbit. (C,D) Postoperative MR control showing subtotal resection with questionable tumor remnant at inferior medial orbital wall. Tumor-infiltrated medial orbital walls and orbit roofs were resected. Reconstruction was performed with split-bone graft and galea-periosteum flap. Titan mesh was used as well. A second-step endoscopic procedure was performed for oncological gross total resection.

Figure 6

Illustration of classic basal bifrontal craniotomy for transbasal approach, complete resection rates, postoperative outcome and complications.

Figure 7

Illustrative case of classic transbasal approach. (A) Typical skin incision and preparation of a galea-periosteum flap for later reconstruction. (B) Bifrontal craniotomy. (C,D) Macroscopic view after bone flap elevation. (E) After initial tumor debulking further exploration by resection of lateral sphenoid wing. (F) Periorbit and left maxillary sinus exposed. (G) Removal of optic strut. (H) Exposure of opticocarotid triangle. (I) Subfrontal, transethmoidal, transsphenoidal and transmaxillary exposure. (J) Macroscopic overview after complete tumor resection. (K) Anterior skull base reconstruction is performed by galea-periosteum flap. (L) Bone flap re-implantation using thin flaps and closure.