C1 laminectomy for retro-odontoid pseudotumor without atlantoaxial subluxation: review of seven consecutive cases

• Published in: European spine journal Vol. 22; no. 5; pp. 1119 - 1126
• Main Authors: Kakutani, Kenichiro, Doita, Minoru, Yoshikawa, Masaho, Okamoto, Koji, Maeno, Koichiro, Yurube, Takashi, Sha, Norihide, Kurosaka, Masahiro, Nishida, Kotaro
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01-05-2013; Springer Nature B.V
• Subjects: Aged; Aged, 80 and over; Atlanto-Axial Joint - diagnostic imaging; Atlanto-Axial Joint - pathology; Atlanto-Axial Joint - surgery; Cervical Atlas - diagnostic imaging; Cervical Atlas - pathology; Cervical Atlas - surgery; Female; Humans; Joint Dislocations - diagnostic imaging; Joint Dislocations - pathology; Joint Dislocations - surgery; Laminectomy - methods; Magnetic Resonance Imaging; Male; Medicine; Medicine & Public Health; Middle Aged; Neurosurgery; Odontoid Process - diagnostic imaging; Odontoid Process - pathology; Odontoid Process - surgery; Original; Original Article; Radiography; Retrospective Studies; Spinal Diseases - diagnostic imaging; Spinal Diseases - pathology; Spinal Diseases - surgery; Surgical Orthopedics; Treatment Outcome; Spontaneous regression; Retro-odontoid pseudotumor; C1 laminectomy
• ISSN: 0940-6719; 1432-0932
• DOI: 10.1007/s00586-013-2681-0

Purpose
A retro-odontoid pseudotumor is usually a reactive fibrocartilaginous mass associated with atlantoaxial subluxation (AAS). However, a retro-odontoid pseudotumor not associated with AAS, which undergoes spontaneous regression following C1 laminoplasty, has been reported. The purpose of this study was to report surgical outcomes of C1 laminectomy for retro-odontoid pseudotumor without AAS.
Materials and methods
The cases of seven patients (mean age 75.6 ± 7.6 years-old) with retro-odontoid pseudotumor without AAS were reviewed. The mean follow up time was 52.3 ± 25.5 months. Each patient underwent a C1 laminectomy with an additional C3–6 expansion laminoplasty in three patients. The Japanese Orthopaedic Association score (JOA score) was used for neurological assessment. Pseudotumor size and additional AAS were analyzed using MRI and radiography.
Results
All patients exhibited neurological improvement following surgery, the JOA score improved from 7.2 ± 3.2 to 14.1 ± 2.6. The mean O-C2 and C2–7 angle decreased from −3.2 ± 2.1° to −3.9 ± 1.7°, showing a slight kyphotic change. Postoperative AAS was not observed. All pseudotumors spontaneously resolved, and recurrence and regrowth were not observed. Five patients had MRIs after gadolinium administration; four patients who showed enhancement of the pseudotumor had almost complete reduction within 1 year following surgery.
Discussion
Our study, assessing the outcome of C1 laminectomy for retro-odontoid pseudotumor, found neurological improvement in all cases. Since all pseudotumors were reduced and additional AAS was not observed, C1 laminectomy for retro-odontoid pseudotumor, in the absence of AAS, is recommended as a therapeutic strategy.