Transnasal Endoscopic and Transoral Approaches in the Biopsies of Ventral Atlas and Axis Vertebrae: A Comprehensive Retrospective Study for Preprocedural Scheme, Biopsy Procedure, Core Technique Analysis, Diagnostic Yield and Clinical Outcome

Abstract

Objective: This study aims to describe and analyze the transoral and transnasal approaches for pathologies of the ventral atlas and axis vertebrae, which are considered technically challenging regions for diagnostic biopsy.

Methods: A series of transnasal endoscopic approach (TNA) and transoral approach (TOA) biopsies for the pathologies of the first and second cervical vertebrae were conducted and retrospectively analyzed from July 2014 to May 2021. The depth of the biopsy trajectory was measured on computed tomography images for all nine patients (eight males and one female with an average age of 58.11 ± 11.60 years), as were the coronal, sagittal, and vertical biopsy safe ranges. The characteristics of each lesion, including radiographic features, blood supply, and destruction of anterior or posterior vertebral body edges, were evaluated to guide the biopsy. Four biopsy core techniques (BCTs), including "lesion perforating", "aspiration", "cutting-and-scraping" and "biopsy forceps utilization" were elaborated in this study. The biopsy procedures and periprocedural precautions were demonstrated. Patient demographics, clinical data, lesion characteristics, diagnostic yield, and complications were recorded for each case.

Results: Eight TOA biopsies for the axis vertebral body and one TNA biopsy for the atlas anterior arch were successfully performed and yielded adequate pathologies. All biopsies were organized based on the preprocedural radiographic measurements, which showed that the average length of biopsy trajectory and coronal, sagittal, and vertical safe biopsy ranges were 85.00 ± 5.88, 20.63 ± 4.75, 16.25 ± 1.49, and 24.63 ± 2.26 mm, respectively, and these corresponding data were 95, 36, 9, and 26 mm in the TNA patient. Six osteolytic lesions (66.7%), one osteoblastic lesion (11.1%), and two mixed lesions (22.2%) were observed, among which seven lesions had a rich blood supply. Biopsy forceps and core needles were utilized to obtain samples in six and three patients, respectively. All the TNA and TOA biopsies were performed with cooperative application of multiple BCTs under compound anatomic and stereotactic navigations. Intraprocedural or postprocedural complications occurred in no patients who underwent the biopsy in the follow-up period (1-39 months). No significant differences were found between the preprocedural and postprocedural blood indexes and visual analogue scale scores.

Conclusion: With a sophisticated preprocedural arrangement, cooperative application of BCTs, and careful periprocedural precautions, transnasal endoscopic and transoral biopsies are two feasible, efficient, and well-tolerated procedures that achieve satisfactory diagnostic yield, complication rate, and clinical outcome.

Keywords: Atlas vertebra; Axis vertebra; Biopsy; Diagnostic yield; Transnasal approach; Transoral approach.

Fig. 1

The application of biopsy core techniques. (A) Lesion perforation under C‐arm fluoroscopy. (B) The aspiration performed after the establishment of the biopsy corridor. (C) The bone biopsy core needle and biopsy forceps. (D) Biopsy forceps utilization in the pertinent case

Fig. 2

The manipulation of the biopsy procedure. (A) The disposal of the oral cavity by the self‐retaining transoral system. (B) The retracted uvula attached to the silicone tubes. (C) The oral and oropharyngeal soft tissues were exposed. (D) Preprocedural localization by a radiopaque needle (arrowhead). (E) The complete establishment of the biopsy trajectory. (F) Posterior pharyngeal wall sutured with absorbable sutures

Fig. 3

Radiographic measurements for biopsy trajectory and biopsy safe range and prebuilt stereotactic biopsy model. (A) The measurements for transnasal endoscopic approach (TNA) biopsy on CT images showing depth of biopsy trajectory (A1), coronal distance (A2), sagittal distance (A3) and vertical distance (A4) of biopsy safe range. The vertical biopsy safe range (arrowhead) and rhinopalatine line (RPL) are displayed in A4. (B) The measurements for transoral approach (TOA) biopsy on CT images showing depth of biopsy trajectory (B1), coronal distance (B2), sagittal distance (B3) and vertical distance (B4) of biopsy safe range. (C) The measurement of the sagittal biopsy safety range for TOA biopsy on MRI. (D) The preplanned safe biopsy ranges (blue areas) on reconstructed stereotactic 3D models. (E) The evaluation of different biopsy trajectories for lesions in the C1 anterior arch via TNA (red line) and virtual TOA (blue line). ∠NTF and ∠OTF represent the angles of the biopsy trajectories via TNA and TOA, respectively. The involvement of the soft palate is shown (dashed lines). Point T, the target biopsy point of the lesion; point F, intersection of the anterior and inferior borders of the axis; point N, the entry point via TNA; point O, the entry point via TOA. (F) The evaluation of different biopsy trajectories for lesions in the C2 body via TOA (red line) and virtual TNA (blue line). ∠NTF and ∠OTF represent the angles of the biopsy trajectories via TNA and TOA, respectively. The involvement of the hard palate and maxillary bone is shown (dashed lines). Point T, the target biopsy point of the lesion; point F, intersection of the anterior and inferior borders of the axis; point N, the entry point via TNA; point O, the entry point via TOA

Fig. 4

Radiographic characteristics of lesions. (A) The osteolytic appearance of lesions in atlas vertebrae from patient 1 (A1) and axis vertebrae from patient 4 (A2) shown on CT images. (B) The osteoblastic appearance of the lesion from patient 6 shown on reconstructed sagittal CT images. (C) The mixed lesion with osteolytic and sclerotic appearance from patient8 shown on reconstructed sagittal CT images. (D) Lesion with rich blood supply from patient 4 judged by MRI. (E) Partially damaged anterior and posterior vertebral body edges of axis vertebra from patient 2

Fig. 5

Macroscopic and microscopic characteristics of the obtained biopsies. (A) The gross appearance of biopsies. (A1) Yellowish, gelatinous mass from patient 1. (A2) Gray‐white and gray‐red hard mass from patient 6. (A3) Gray‐red solid mass from patient 8. (A4) Gray‐red soft mass from patient 7. (B) The histopathological characteristics of biopsies. (B1) Chordoma (after immunohistochemical identification) from patient 1. (B2) Metastatic tumor cells infiltrated by inflammatory cells (after immunohistochemical identification) from patient 6. (B3) Vertebral hemangioma (after immunohistochemical identification) from patient 8. (B4) Acute and chronic inflammatory cells and normal osseous tissues from patient 3