OUTCOME OF SUBOCCIPITAL DECOMPRESSION WITH AND WITHOUT DURAPLASTY IN ADULTS WITH CHIARI I MALFORMATION

ABSTRACT
Objectives: To investigate outcome for ACM1 patients based on intervention methods, i.e., posterior fossa decompression
without duraplasty and with duraplasty in terms of symptomatic and functional improvement.
Methods: This study was conducted prospectively over 41 months from January 2013 to May 2016. Patients with confirmed
diagnosis of ACM-1 were included in the study. Patients either underwent posterior fossa decompression without
duraplasty or with duraplasty, depending upon the severity of tonsillar descent, the presence of syrinx, neurological
deficits or hydrocephalus. Data was collected on pre-designed pro forma both preoperatively and during follow up. Outcome
was assessed according to Chicago Chiari Outcome Scale (CCOS). Data analysis was done using SPSS v 22.0.
Results: PFD without dural opening was performed in 13 patients while in 8 patients duraplasty was performed. Overall
mean age was 32.95±5.88 years and mean symptoms duration was 21.62±8.82 months. The most common complaints
were headache (76.2%), neck pain (61.9%), hand and arm weakness (47.6%), gait disturbance (47.6%) and cranial
nerve dysfunctions (76.2%). The median preop CCOS was 10±1.57 while postoperative CCOS was 13±2.27. There
was a significant relief in terms of CCOS improvement in preop and postoperative scores (P<0.0001). Similarly, on Chisquare
analysis there was no significant difference between favourability of outcome for the two types of intervention.
50% favourable outcome was obtained for PFD without duraplasty and 50% for PFD with duraplasty. On Chi-square
analysis, PFD with duroplasty was significantly associated with the occurrence of postoperative complications (p =
0.006). The commonest complication was CSF leak in 14.3% of patients. There was no mortality. No recurrent cases
were noted during the 41-months study period.
Conclusion: Posterior fossa decompression for ACM-I is simple and effective. Further studies regarding surgical outcome
and development of outcome assessment are required with larger patient cohorts.
Keywords: Arnold Chiari Malformation, Posterior fossa decompression, Chicago Chiari Outcome Scale, Duraplasty