Craniovertebral junction anomalies: When is resurgery required?

BACKGROUND

Craniovertebral junction (CVJ) abnormalities, such as atlantoaxial dislocation (AAD) with or without basilar invagination (BI), with or without associated Chiari malformation (CM), may cause a high cervical myelopathy. Occasionally, mechanical factors such as inadequate canal decompression, torticollis, and/or scoliosis may lead to lack of improvement following the primary surgery. Furthermore, implant-related factors, requiring implant revision/removal, or the presence of surgical site infections may cause the patient to undergo resurgery.

AIMS: This study was aimed at highlighting the underlying etiopathogenesis of resurgery following the primary surgery undertaken in CVJ abnormalities.

SETTING AND

DESIGN

This was a retrospective study from a tertiary care referral institute focusing on 414 operated cases of CVJ anomalies.

MATERIALS AND

METHODS

The data of 55 patients who underwent resurgery included their clinicoradiological assessment and operative records. The inclusion criteria included failed primary procedure, repeat procedure for construct failure, infection at the surgical site, or wound dehiscence. Pure CM patients without bony anomalies were excluded from the study.

RESULTS

A total of 137 procedures were performed in 55/414 (13%) patients. Causes of resurgery could be divided into ventral [redo or denovo transoral decompression (TOD) or wound-related complications, n = 33, 40.2%] and dorsal causes (implant-related factors/wound infections, n = 49, 59.8%). De novo TOD was done in persisting myelopathy following posterior fusion (PF) with C1-2 distraction (n = 15,18.3%,). Redo TOD was done for residual anterior bony compression [n = 8, 9.6%, OR 0.61; [CI = 0.20-1.86]. Causes for oral wound reexplorations (n = 10, 12.2%) included velopharyngeal insufficiency, wound resuturing, oral bleeding, and cerebrospinal fluid (CSF) leak. Dorsal causes included: (A) Implant factors (n = 27, 32.7%) and (B) neck wound reexplorations (n = 22, 26.8%). Presence of subaxial spine scoliosis, torticollis, and asymmetric joints increased the incidence of reexploration. Occipitocervical fusion rather than C1-2 fusion was more prone towards construct loosening.

CONCLUSIONS

Patients undergoing distraction with PF may require transoral surgery due to persisting myelopathy, especially in the presence of torticollis, scoliosis, and symmetrical joints. Single stage TOD+PF increases the chances of implant infection due to tissue contamination, bacteremia, or transfacetal migration of microbes. Chronic/recurrent sinus is usually a harbinger of deeper infection and can be cured with implant removal.