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

Abstract

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.

Retro-odontoid mass without atlantoaxial instability causing cervical myelopathy: a case report of transdural surgical resection

“…The improved blood flow in the neovascularized area caused by C1 laminectomy may contribute to regression of the retro-odontoid pseudotumor, similarly to the disappearance of herniated nucleus pulposus. 13 However, in the present case the pseudotumor had poor neovascularization. Thus, it is possible that another mechanism promotes the pseudotumor disappearance.…”

“…Takemoto et al 15 reported that C1 laminectomy is beneficial, especially for elderly patients, given the risk of other surgical options using an anterior transoral approach or posterior fusion. However, most tumors do not attenuate after C1 laminectomy alone; 13 hence, we dentriculate ligament…”

“…[8][9][10] By contrast, some surgeons have used a posterior approach to avoid the morbidity of a transoral approach. [12][13][14][15] It has been reported that C1/C2 or C0/C3 fixation techniques can guarantee the same results for reduction or regression of retro-odontoid pseudotumors and spinal cord decompression under both inflammatory and degenerative conditions. 12 Kakutani et al 13 reported that C1 laminectomy without fusion resulted in spontaneous regression of pseudotumors and alleviation of the neurological deficit in all patients.…”

“…[12][13][14][15] It has been reported that C1/C2 or C0/C3 fixation techniques can guarantee the same results for reduction or regression of retro-odontoid pseudotumors and spinal cord decompression under both inflammatory and degenerative conditions. 12 Kakutani et al 13 reported that C1 laminectomy without fusion resulted in spontaneous regression of pseudotumors and alleviation of the neurological deficit in all patients. However, spontaneous mass regression is reported after posterior fusion even in the absence of radiographical atlantoaxial instability.…”

Radiographic and Clinical Results of C1 Laminoplasty for the Treatment of Compressive Myelopathy

“…C1 laminectomy has been the standard procedure for decompression at the C1 level [1,2]. Discussion has been had regarding whether fusion surgery or decompression surgery is a better treatment for compressive myelopathy with pseudotumor at the upper cervical level.…”