Type I Chiari Malformation Without Concomitant Bony Instability: Assessment of Different Surgical Procedures and Outcomes in 73 Patients

• Published in: Neurospine Vol. 18; no. 1; pp. 126 - 138
• Main Authors: Rangari, Kamlesh, Das, Kuntal Kanti, Singh, Suyash, Kumar, Krishna G, Bhaisora, Kamlesh Singh, Sardhara, Jayesh, Mehrotra, Anant, Srivastava, Arun Kumar, Jaiswal, Awadhesh Kumar, Behari, Sanjay
• Format: Journal Article
• Language: English
• Published: Korea (South) Korean Spinal Neurosurgery Society 01.03.2021; 대한척추신경외과학회
• Subjects: chiari malformation; functional outcome; Original; posterior fixation; posterior fossa decompression; predictors; syrinx; 신경외과학; Posterior fossa decompression; Posterior fixation; Chiari malformation; Syrinx; Functional outcome; Predictors
• ISSN: 2586-6583; 2586-6591
• DOI: 10.14245/ns.2040438.219

Posterior fossa decompression is the treatment of choice in type 1 Chiari malformation (CM-1) without bony instability. Although surgical fixation has been recommended by a few authors recently, comparative studies to evaluate these treatment strategies using objective outcome tools are lacking. Seventy-three patients with pure CM-1 (posterior fossa bony decompression [PFBD], n = 21; posterior fossa bony and dural decompression [PFBDD], n = 40; and posterior fixation [PF], n = 12) underwent a postoperative outcome assessment using Chicago Chiari Outcome Score (CCOS). Logistic regression analysis detected predictors of an unfavorable outcome. Minimally symptomatic patients generally underwent a PFBD while most of the clinically severe patients underwent a PFBDD (p = 0.049). The mean CCOS score at discharge was highest in the PF (12.0 ± 1.41) and lowest in PFBDD group (10.98 ± 1.73, p = 0.087). Patients with minimal preoperative clinical disease severity (adjusted odds ratio [AOR], 4.58; 95% confidence interval [CI], 1.29-16.31) and PFBDD (AOR, 7.56; 95% CI, 1.70-33.68) represented risks for an unfavorable short-term postoperative outcome. Though long-term outcomes (CCOS) did not differ among the 3 groups (p = 0.615), PFBD group showed the best long-term improvements (mean follow-up CCOS, 13.71 ± 0.95), PFBDD group improved to a comparable degree despite a poorer short-term outcome while PF had the lowest scores. Late deteriorations (n = 3, 4.1%) occurred in the PFBDD group. Minimally symptomatic patients and PFBDD predict a poor short-term postoperative outcome. PFBD appears to be a durable procedure while PFBDD group is marred by complications and late deteriorations. PF does not provide any better results than posterior fossa decompression alone in the long run.