Posterior fossa decompression with duraplasty in chiari 1. Dr. Iram Bokhari Dr. Lal Rehman Dr. Hamid Akbar Prof A. Sattar M. Hashim JPMC, Karachi.

Introduction In 1891, Chiari (Professor of Pathology) was described a patient with herniation of the cerebellar tonsils below the foramen magnum.

Introduction…contd.

Introduction…contd. Chiari 1 malformation is described as caudal displacement of cerebellar tonsils below the level of foramen magnum, more than 5 mm is generally considered

Aims & Objectives - To find out the symptomatic outcome after decompressive duraplasty in chiari 1 malformation.

Material & Methods Design Descriptive case series Duration July, 2008 – October, 2012 Patient Twenty one Inclusion All patients of symptomatic chiari1 malformation with syrinx

Age

Male / Female

Clinical Features Pts Pain Hand wk Numbness L/L 21 12 3

Operative Management Procedure No: of Pts 21 01 02 PFD with Duraplasty syringosubarachnoid shunt 01 ventriculoperitoneal shunt 02 PFD=posterior fossa decompression

Prone Position for Surgery

Results Pre Op Post Op Pain Hand wk numb L/L Pain 21 -- Hand wk 12 03 -- Hand wk 12 03 Numbness 21 02 L/L 03 01

Post Op Complications Complication PTS CSF LEAK 01 WOUND INFECTION DETERIORATION NIL VA O1 MORTALITY

Discussion Chiari 1 malformation is caudal decent of cerebellar tonsil >5mm below the foramen magnum Generally no descent of brain stem Not associated with Mylomeningocele Syrinx 50% - 75% Hydrocephalus 1 – 10% Platybasia, basilar invagination, Klippel-feil, scoliosis are also seen

Discussion…contd. Hydrodynamic theory of Gardner stated that delayed opening of 4th ventricle outlets results in transmission of arterial pulse through a patent obex, producing a waterhammer effect that enlarges the central canal. Williams theory of craniospinal pressure dissociation states that different pressures that exist between the cranial and spinal cavities causing syringomyelia.

Pain, head ache, numbness and weakness are major presenting symptoms Pain, head ache, numbness and weakness are major presenting symptoms. These are also true in our series JPMC Gregg N et al Pain 100% 81.5% Weakness 57% 70% Numbness 66%

Discussion..contd. The surgical management of Chiari malformation has centered on bone decompression of foramen magnum. Penfield and Cobern published 1st case of a posterior fossa decompression. Gardner and Goodall proposed plugging the communication at obex with posterior fossa decompression.

Discussion…contd. Logue and Edwards reported seven cases of laminectomy and syringosubarachnoid shunt after posterior fossa decompression had failed but obtain poor results. Gregg N et al experience good results when posterior fossa decompression was combined with obex obliteration, 4th ventricle shunting and a dural graft.

Discussion…contd. Our experience shows good results when posterior fossa decompression with duraplasty was done.

Conclusion Chiari 1 occurs in younger age Common in female Features MRI Surgical Options PFD with Duraplasty has good results.

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