Hydrocephalus.Dr NG NeuroEdu

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Hydrocephalus.Dr NG NeuroEdu

  1. 1. HYDROCEPHALUS Dr. Nishantha Gunasekera MBBS, MS, MRCS(Eng) Consultant Neurosurgeon
  2. 2. Introduction  Complex series of diseases  Interaction of multiple organs (brain, csf, blood)  Inside a semi-enclosed space  Fundamental change is perturbation of – ICP – Intracranial volume  Usually accompanied by changes in ventricular sizeDr. Nishantha GunasekeraMBBS, MS, MRCS
  3. 3. Cntd.  Degree of change in ventricular volume limited by 1. Volume of material inside the cranial vault 2. Intrinsic brain properties Elasticity, Fluid flow, Porosity, Compliance Atrophy etc. A mathematical model can be applied to predict changes Neurosurgery Focus 22 (4):E3, 2007 Michelle J. Clarke MD, Frederic B Meyer MD:Dr. Nishantha GunasekeraMBBS, MS, MRCS
  4. 4.  Adequate understanding of hydrocephalic diseases involve the interaction 4 major research arms 1. Basic science Physical parameters or organ properties (eg. Intracranial volumes...) Understanding disease on a cellular level (eg. Oedema, tumours...) 2. Computer based mathematical modelling Macroscopic biomechanical framework 3. Animal studies Platform to test theoretical interventions 4. Clinical correlation Accuracy of the model systemsDr. Nishantha GunasekeraMBBS, MS, MRCS
  5. 5. HISTORY Ancient Greeks : ventricular puncture Hippocrates : first attempt at CSF drainage 1898 : shunt into peritoneal cavity (silver wire thru’ L5 into peritoneum hoping for a fistula!) 1907 : diversion into SSS (mortality at 4 months, 100%) 1908 (Cushing) : first VP shunt 1910 (Lespinasse) : first attempt at endoscopic cauterization of choroid plexus 1918 (Dandy) : surgical extirpation of CP 1939 (Torkildsen) : shunt from lat.vent. to cisternaDr. Nishantha GunasekeraMBBS, MS, MRCS magna (50% mortality)
  6. 6. HISTORY Many body cavities served as the distal terminus for CSF diversion. (mastoid, salivary glands, thoracic duct, spinal epidural space, bone marrow, omental bursa, stomach, gallbladder ,ileum, ureter , fallopian tube !) 1952 (Nulsen and Spitz) : first valve system to prevent reflux of blood 1955 : first successful ventricular- atrial shunt 1955 (Holter) : multiple slit valve made of silicone 1960 (Ransohoff et al) : 65% success withDr. Nishantha GunasekeraMBBS, MS, MRCS ventricular-pleural shunts
  7. 7. HISTORY 1963 (Scarff) : 55% of 230, had arrested hydrocephalus after VP shunting 1970 (Ames) : suggested peritoneum was best, but risk of infection (rate of VP shunting rose rapidly) 1979 (George et al) : VA and VP shunts showed similar infection rates The seventies : V-Peritoneal shunting established as first line therapy for hydrocephalus Future : Endoscopy, antisiphon devices, kink resistant tubes, silastic and new alloys,Dr. Nishantha Gunasekera flow regulation, programmable shunts..MBBS, MS, MRCS
  8. 8. HYDROCEPHALUS Anatomy & Physiology of CSF Circulation Definition Pathogenesis Classification Clinical Syndromes Investigations Management The FutureDr. Nishantha GunasekeraMBBS, MS, MRCS
  9. 9. HYDROCEPHALUS Anatomy and Physiology of CSF Circulation Production  80% by choroid plexus (95% lateral ventricles)  Interstitial spaces  Ependymal lining  Dura of nerve root sleeves  Rate 0.3ml/min, 450/24h  (largely independent of ICP!)  Turnover 3x /24hDr. Nishantha GunasekeraMBBS, MS, MRCS
  10. 10. HYDROCEPHALUS Anatomy and Physiology of CSF Circulation Absorption  Primarily by arachnoid villi bulk flow thru’ villi or absorbed from hemisphere surface?)  Choroid plexus  Rate of absorption pressure dependentDr. Nishantha GunasekeraMBBS, MS, MRCS
  11. 11. HYDROCEPHALUS Anatomy and Physiology of CSF Circulation Property Paediatric Adult newborn 1-10yrs Total 5 varies with 150 (50% volume(ml) age cranial 50% spine) Formation 25 changes 450-750 rate(ml/d) with age Pressure 9-12 mean 10 7-15 (cm fluid) normal <15 (>18Dr. Nishantha Gunasekera abnormal)MBBS, MS, MRCS
  12. 12. HYDROCEPHALUS Definitions  An increase in CSF volume, in an enlarged ventricular system, usually resulting from impaired absorption, rarely from excessive secretion.  This definition excludes hydrocephalus ex vacuo. (atrophy, Alzheimer’s, CJD)  Prevalence: 1-1.5%  Incidence cong. HCP 0.2-3.5/1000 births – Upto 20% after SAHDr. Nishantha GunasekeraMBBS, MS, MRCS – 1% after meningitis
  13. 13. HYDROCEPHALUS Pathogenesis  Fundamentally caused by disturbed csf circulation or absorption  Pressure gradient between cortical subarachnoid space and ventricular system  Sudden obstruction of csf pathways causes immediate rise in R(out) and ICP, followed usually by HCP  This results almost always in symptomsDr. Nishantha GunasekeraMBBS, MS, MRCS and signs
  14. 14. HYDROCEPHALUS Pathogenesis  Cytological changes are found in cortical areas and in the white matter  Especially in the periventricular white matter  Ependymal lining is flattened  Subependymal layer becomes degenerated and its function decreasesDr. Nishantha GunasekeraMBBS, MS, MRCS
  15. 15. HYDROCEPHALUS Pathogenesis  Ventricular enlargement is NOT uniform  Begins in the lat. ventricles  Mostly in the frontal and occipital horns  The areas of least resistance  Volumes diminish in the cerebral sulci, fissures and cisternsDr. Nishantha GunasekeraMBBS, MS, MRCS
  16. 16. HYDROCEPHALUS Pathogenesis  Periventricular lucency  Sharp demarcation between the oedematous and normal white matter  CT or MRI correlates well with the ICP and R(out)Dr. Nishantha GunasekeraMBBS, MS, MRCS
  17. 17. HYDROCEPHALUS Classification  Classified in many ways .. no consensus as yet!  However, practical systems have survived  Functional classification Clinical Age wise Pathological /Aetiological ICP and/or R(out) There fore a Multi-axial Classification is suggestedDr. Nishantha GunasekeraMBBS, MS, MRCS
  18. 18. HYDROCEPHALUS Classification- Functional Obstructive Communicating (Non communicating) (Non obstructive) Block proximal to the Block at the level of arachnoid granulations arachnoid granulations eg. aqueduct stenosis eg. Post meningiticDr. Nishantha GunasekeraMBBS, MS, MRCS
  19. 19. HYDROCEPHALUS Classification- Functional Pituitary Communicating ObstructiveDr. Nishantha GunasekeraMBBS, MS, MRCS
  20. 20. HYDROCEPHALUS Classification- Clinical  1. High pressure hydrocephalus – Acute – Chronic  2. Normal pressure hydrocephalus  3. Arrested hydrocephalusDr. Nishantha GunasekeraMBBS, MS, MRCS
  21. 21. HYDROCEPHALUS Classification- Age 1. Paediatric 2. Juvenile/adult Symptoms and signs differ considerably Therefore a very useful classificationDr. Nishantha GunasekeraMBBS, MS, MRCS
  22. 22. HYDROCEPHALUS Classification- Aetio-pathological  Congenital a. Chiari type 2 malformation and or meningomyelocoele (paeds, vermis, medulla ) b. Chiar type 1 malformation (young adults, tonsils) c. Primary aqueductal stenosis d. Secondary aqueductal gliosis (IU inf. /geminal matrix h’rhage e. Dandy-Walker malformation (2.4% of HCP) f. Rare X linked inherited disorderDr. Nishantha GunasekeraMBBS, MS, MRCS
  23. 23. HYDROCEPHALUS Classification- Aetio-pathological  Acquired a. Infectious (most cmn. cause of com.HCP) - Post meningitic (esp. purulent, basal, incl. TB) - Abscess - Cysticercosis, granuloma b. Post haemorrhagic(2nd most cmn cause of com.HCP) - Post SAH - Post IVH (transient but 20-50% permanent HCP ) - Trauma c. Secondary to masses - Non neoplastic (eg. Vascular malformations, arachnoid cysts) - Neoplastic (block CSF pathways) Medulloblastoma, colloid cyst, pituitary tumour, suprasellar t. - Choroid plexus papilloma (inc. production + block) - Post op (20 % paed. pts. Require shunts after P. fossa tumourDr. Nishantha Gunasekera removal)MBBS, MS, MRCS
  24. 24. HYDROCEPHALUS Classification- Aetio-pathological Cntd. d. Post op (20% paeds. develop permanent HCP requiring shunt foll. P- fossa tumours) e. Neurosarcoidosis f. Constitutional ventriculomegaly (asymtomatic- no Rx) g. Associated with spinal tumoursDr. Nishantha GunasekeraMBBS, MS, MRCS
  25. 25. HYDROCEPHALUS Classification- ICP / R(out)  High pressure monitored ICP >= 15mmHg R(out) increased B waves symptoms depend on the speed of development of HCP CBF and metabolism reduced periventricularly  Normal pressure Monitored ICP <15mmHg R(out) increased Global CBF and metabolism usually normal Management implicationsDr. Nishantha GunasekeraMBBS, MS, MRCS
  26. 26. HYDROCEPHALUS Clinical syndromes Age Infants and young Juvenile and Onset children adults Acute Irritability, low GCS,V, HA, V, Papillodema, tense font. low GCS, upward gaze palsy Chronic MR, fail to thrive, cracked GAIT ATAXIA pot, inc.skull circ., lid INCONTINENCE retraction, Parinauds synd. DEMENTIA (setting sun), thin scalp & (classic triad of NPH) skull, dil. veins +Visual lossDr. Nishantha GunasekeraMBBS, MS, MRCS
  27. 27. HYDROCEPHALUS Investigations  CT  MRI  ICP  R(OUT) Measured using specialized equipment and infusion sets  Isotope cisternographyDr. Nishantha GunasekeraMBBS, MS, MRCS
  28. 28. HYDROCEPHALUS 4th ventricle NOT dilatedDr. Nishantha GunasekeraMBBS, MS, MRCS
  29. 29. HYDROCEPHALUS Complicated dilatation of ventriclesDr. Nishantha GunasekeraMBBS, MS, MRCS
  30. 30. HYDROCEPHALUSNPH? Dr. Nishantha Gunasekera MBBS, MS, MRCS
  31. 31. HYDROCEPHALUS Post IVHDr. Nishantha GunasekeraMBBS, MS, MRCS
  32. 32. HYDROCEPHALUSPOST MENINGITIC Dr. Nishantha Gunasekera MBBS, MS, MRCS
  33. 33. HYDROCEPHALUSAqueduct stenosis Dr. Nishantha Gunasekera MBBS, MS, MRCS
  34. 34. CT parameters for Diagnosis of HCP FH = inter frontal horn diameter ID = internal diameter a. b. TH = Temporal horn diameter >2mm MID Evans ratio = FH: Maximum interparietal c. diameter >30%=HCP Mickey mouse sign!Dr. Nishantha GunasekeraMBBS, MS, MRCS
  35. 35. Resistance to outflow of CSF  This is a more involved test  Requires a specialized hospital setting.  In essence, this test assesses the degree of blockage to CSF absorption back into the bloodstream.  It requires the simultaneous infusion of artificial spinal fluid and measurement of CSF pressure.  Spinal subarachnoid space is cannulated  ICP monitor is inserted  ICP is monitored while fluid is infused into the subarachnoid space  If the calculated resistance value is abnormally high, then there is a very good chance that the patient will improve with shunt surgery.  Unit of measurement is mmHg/ml/minDr. Nishantha GunasekeraMBBS, MS, MRCS
  36. 36. Isotopic cisternography:  Radioactive isotope injected into the lumbar subarachnoid space (lower back) through a spinal tap.  This allows the absorption of CSF to be evaluated over a period of time (up to 96 hours) by periodic scanning.  This will determine whether the isotope is being absorbed over the surface of the brain or remains trapped inside the ventricles.  Isotopic cisternography involves spinal puncture and is considerably more involved than either the CT or MRI.  This test has become less popular because a "positive" cisternogram result does not reliably predict whether a patient will respond to shunt surgery.Dr. Nishantha GunasekeraMBBS, MS, MRCS
  37. 37. HYDROCEPHALUS Management flow chart Clinical signs of HCP Signs of high pressure Signs of NPH HCP HCP (-) Obstructive Further tests CT CT shunt HCP (+) nonobstructive ICP monitoring and MRI Ventriculostomy perfusion test raised ICP? shunt normal No Shunt B Waves? shunt <5% >50% 5-50% No Shunt R out? shunt >12mmHg/ml/minDr. Nishantha Gunasekera <12MBBS, MS, MRCS
  38. 38. The basic shunt valve systemDr. Nishantha GunasekeraMBBS, MS, MRCS
  39. 39. Assessment of Shunt functionDr. Nishantha GunasekeraMBBS, MS, MRCS
  40. 40. Radiological appearanceDr. Nishantha GunasekeraMBBS, MS, MRCS
  41. 41. Management- PositioningDr. Nishantha GunasekeraMBBS, MS, MRCS
  42. 42. Management- Upper end position of catheter tipDr. Nishantha GunasekeraMBBS, MS, MRCS
  43. 43. Management- Upper endDr. Nishantha GunasekeraMBBS, MS, MRCS
  44. 44. Management- Upper end Keens PointDr. Nishantha GunasekeraMBBS, MS, MRCS
  45. 45. Management- lower endDr. Nishantha GunasekeraMBBS, MS, MRCS
  46. 46. Management- lower endDr. Nishantha GunasekeraMBBS, MS, MRCS
  47. 47. Management- lower endDr. Nishantha GunasekeraMBBS, MS, MRCS
  48. 48. Management – Laparoscopic Insertion of Peritoneal CatheterDr. Nishantha GunasekeraMBBS, MS, MRCS
  49. 49. Management – Removal of TrocharDr. Nishantha GunasekeraMBBS, MS, MRCS
  50. 50. Management –Intraperitoneal viewDr. Nishantha GunasekeraMBBS, MS, MRCS
  51. 51. Complications  Undershunting  Infection  Overshunting  Siezures  Distal catheter problems  Skin breakdown over hardware  Silocone allergyDr. Nishantha GunasekeraMBBS, MS, MRCS
  52. 52. Evaluation of shunt function  History and examination  Radiographic evaluation (X rays, CT, MRI)  Shunt-o-gram – Radioneuleid shun-to-gram (1mCi of Tc pertechnetate in 1cc fluid) – X ray shunt-o-gram(omnipaque 180)Dr. Nishantha GunasekeraMBBS, MS, MRCS
  53. 53. Programmable shunt systems Programming with ext. magnet Fig. 4. Dig ita l p a lp a -tio n a nd lo c a liz a tio n o f v a lve with e x te rna l p ro g ra m m e r o ve rla y . (I tra tio n c o urte s y o f Co d m a n, a Jo hns o n & Jo hns o n llusDr. Nishantha Gunasekera Co , Ra y nha m , M s s . ) aMBBS, MS, MRCS
  54. 54. Programmable shunts- mechanismDr. Nishantha GunasekeraMBBS, MS, MRCS
  55. 55. The spiral CamDr. Nishantha GunasekeraMBBS, MS, MRCS
  56. 56. Radiology of correct placementDr. Nishantha GunasekeraMBBS, MS, MRCS
  57. 57. Radiology of the pressure valve Fig. 8A. Ra d io g ra p h o f a 3 5 -y e a r-o ld m a n re fe rre d fo r a ro u-tine p re s s ure s e tting c he c k. The PACa ld we ll p ro je c tio n is d if- fic ult to inte rp re t d ue to va lv eDr. Nishantha Gunasekera s up e rim p o s itio n o n the p e tro us rid g e (a rro w).MBBS, MS, MRCS
  58. 58. Correct position for imagingDr. Nishantha GunasekeraMBBS, MS, MRCS
  59. 59. Detailed view of valve pressure indicatorDr. Nishantha GunasekeraMBBS, MS, MRCS
  60. 60. Programmable shunt- settings on x-rayDr. Nishantha GunasekeraMBBS, MS, MRCS
  61. 61. Chest and abdomenDr. Nishantha GunasekeraMBBS, MS, MRCS
  62. 62. Before and after - progammable shunt with regular adjustments Fig. 6B. CT im a g e o f the s a m e p a tie nt a s in 6 Aa fte r p la c e m e nt o f a Fig. 6A. Sp in-e c ho , T1 -we ig hte d tra ns a x ia l M im a g e d e m o n-s tra ting R Co d m a n Ha kim va lve , d e m o ns tra ting s hunt (white line a r o b je c t) a nd v e ntric ulo m e g a ly o f the la te ra l v e ntric le s in a 6 4-y e a r-o ld wo m a n with d e c re a s e d ve ntric ula r s iz e . no rm a l-p re s s ure hy d ro c e p ha lus .Dr. Nishantha GunasekeraMBBS, MS, MRCS
  63. 63. Synopsis1. Complex and common group of conditions2. Clinical syndromes vary3. Choosing the correct intervention needs proper clinical evaluation and target investigations4. Selectively intervene depending on the individual case5. Many options are available, shunts have stood the test of time6. Some may not require shunts but observation7. Minimally invasive techniques are available8. Meticulous surgical technique to avoid complications9. Sophisticated shunt systems can circumvent some shunt related problems10. Majority of patients can be gainfully integrated into societyDr. Nishantha GunasekeraMBBS, MS, MRCS

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