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

Abstract

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. Methods: 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. Results: 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. Conclusion: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.

Relationship Between Syrinx Resolution and Cervical Sagittal Realignment Following Decompression Surgery for Chiari I Malformation Related Syringomyelia Based on Configuration Phenotypes

“…Decompression surgery with or without duraplasty is commonly used to control the development of syringomyelia, which has been reported in previous studies [ 24 - 27 ]. Although traditional surgical methods, such as PFD or PFDD, show certain curative effects in controlling the development of syrinx, they are not beneficial for all patients with syringomyelia.…”

“…Decompression surgery with or without duraplasty is commonly used to control the development of syringomyelia, which has been reported in previous studies. [24][25][26][27] Although tra- ditional surgical methods, such as PFD or PFDD, show certain curative effects in controlling the development of syrinx, they are not beneficial for all patients with syringomyelia. However, intradural pathology in various forms may cause CSF circulation obstruction, which makes great significance in the pathogenesis and outcome of syringomyelia.…”

Stealth cranioplasty in symptomatic adult chiari 1 malformations: Experience at Bangabandhu Sheikh Mujib Medical University

“…The late presentation with longer duration of symptoms and signs in our study reflects the negligence of patients as well as financial constraints in some cases although more than three years of symptom duration are not uncommon. 25,27 Duration of symptoms has profound influence over outcome as literatures show that the longer the duration of symptoms, the worse is the prognosis. This stresses the urgency to diagnose and treat at the earliest to prevent or even to reverse the deficits in some cases.…”

“…31,32 CCOS is being used widely to assess postoperative outcome of CM1 patients and has become a reliable tool. 25,27,33,34 Post-operative outcome can be measured with CCOS in 2 ways; by assessing improvement with the overall score and by categorizing the patient into functional outcome groups based on that score. Most of the studies on adult CM1 patients show that the average CCOS that could be achieved ranges between 13 to 14.5.…”

“…Complication rate varies from zero complication to as high as 33.3% in different series. 25,27,30,33,34,36 Common complications include cerebrospinal fluid leak, pseudomeningocele, meningitis, wound infection, hydrocephalus, subdural collections, and often a less common cerebellar slump or ptosis. 26,27,30,34,37 It is well established that the complication rates, particularly the CSF related ones occur more following procedures that breach the arachnoid, while extradural or arachnoid preserving procedures are evidently better in avoiding CSF related complications.…”