Spina bifida

INCOMPLETE DEVELOPMENT OF BRAIN,SPINAL CORD &MENINGES

1. SPINA BIFIDA DR.SUNIL KAMBLE ASSISTANT PROFESSOR DEPT.OF GEN.SURGERY MNR MEDICAL COLLEGE,SANGAREDDY

2. Definition Incidence and prevalence Causes Risk factors Embryology Classification Screening and diagnosis Treatment Physical therapy Prevention Prognosis Take home message

3. Spina bifida is a developmental abnormality caused by a failure of fusion of the vertebral arches and possibly the underlying neural tube,characterised by the incomplete development of the brain,spinal cord,meninges .(2,7) Spina bifida is a primary neurological disorder.(7)

4. Incidence and Prevalence Spina bifida cystica-1:300 live births.(7) Associated with hydrocephalus. More common in hispanics and caucasians . Worldwide incidence 400,000 per annum. Folic acid use has reduced incidence by 70% in the past 20 yrs. Ireland 1979-32 per 10,000 1982-22 per 10,000(2)

5. C auses Not known. Genetic , nutritional, and environmental factors play a role. Deficiency of folic acid.

6. Risk factors A. Couples who already had an affected baby B. Obese women C. Diabetes D. Anti-seizure medicines E. Folic acid deficiency F. Mutation in methylenetetrahydrofolate reductase gene

7. Embryology Formation of notochord Origin : primitive node/pit Like the primitive streak , the primitive pit cells proliferate and then migrate cranially in the midline , towards the buccopharyngeal membrane , and form a rod like notochordal process.(3)

8. Neurulation It is the process by which the neural tube is formed. The stages of neurulation include the formation of: Neural plate Neural groove Neural folds and their fusion Neural crest cells Neural tube

9. Begins during early part of the 4 th week(22-23 days). Ends by the end of 4 th week(27 days). Is induced by the notochord.

10. Under the inducing effect of the developing notochord, the overlying ectodermal cells thickens to form the neural plate.

11. The neural tube broadens and extends cranially as far as the buccopharyngeal membrane , and later on grows beyond it.

12. On 18 th day : the neural plate invaginates to form neural groove and neural folds.

13. By the end of 3 rd week , the neural folds move to the midline and fuse to form the neural tube. The fusion begins in cervical region and then extends both in cranial and caudal direction.

14. The neural tube separates from the surface ectoderm , lies in the midline ,dorsal to the notochord.

15. Neural tube is open at both ends communicating freely with the amniotic cavity. The cranial opening , the rostral neuropore closes at about 25 th day and the caudal neuropore closes at about the 27 th day.

16. The cranial 1/3 of the neural tube represent the future brain. The caudal 2/3 represents the future spinal cord.(6)

17. Neural Tube D evelopment Neural plate development-18 th day Cranial closure-24 th day(upper spine) Caudal closure-26 th day(lower spine)

18. Types of Neural T ube D efects ANENCEPHALY Brain and skull poorly developed Death inevitable Failure of skin and muscle formation Variable outcome Urgent closure Exposed neural tissue 90% need VP shunt Distal limb innervation affected Neuropathic bladder MENINGOCELE Failure of spinal fusion Dural sac protrudes Usually no neural consequences Rarely bladder function affected Skin covered defect

19. ENCEPHALOCELE Usually occipital Defect in cranial bone Herniation of meninges and brain to varying degree Variable outcome Sometimes shunt needed SPINA BIFIDA Occulta Hamartoma at site Sinus occasionally Skin intact Bony vertebral arch deficient Excellent outcome

20. Types Of N eural T ube D efects

21. Spinal R achischisis Developmental birth defect involving the neural tube. In utero, the neural tube fails to close completely. This anomaly originates when the posterior neuropore fails to close by the 27 th intrauterine day. As a consequence the verterbrae overlying the open portion of the spinal cord do not fully form and remain unfused and open , leaving the spinal cord exposed .

22. Patients with rachischisis have motor and sensory deficits, chronic infections, and disturbances in bladder function. This defect often occurs with anencephaly.

23. Encephalocele Midline defect in the bones of the skull, which allows protrusion of meninges only or gross herniation of brain tissue. 10% of neural tube defect. Common in female. The usual bony site is the occipit but frontal encephaloceles are more common and only seen in Asia.

24. A ssociated Microcephaly Cerebral anomalies Dandy-Walker C yst formation Hydrocephalus Dysplasia of cerebellum and optic pathway Congenital lesions such as cleft palate ,cardiac ,lung and renal anomalies.

25. Classification Spina bifida occulta Spina bifida cystica : Meningocele Myelomeningocele Encephalocele

26. M eningocele Cele -sac(Latin word) Fluid filled sac with meninges involved but neural tissue unaffected.

27. Uncommon Presents as swelling along the spinal cord. Site;lumbar region No neurological defect. Spinal cord is normal. Lower limbs are normal.

28. Myelomeningocele The unfused portion of the spinal column allows the spinal cord to protrude through an opening. The meningeal membranes that cover the spinal cord form a sac enclosing the spinal elements. Commonest form. Most severe.

29. Most common site-lumbar and sacral areas. Presents as swelling along the spinal columns.

30. Associations Hamartomatous lesions : H emangioma , lipoma or a naevus Deformities of the lower limbs Hip dislocation or subluxation Hypoplastic lower limbs Genu recurvatum Talipes deformities of feet Hydrocephalus Severe kyphosis

31. Neurological deficits : Motor and sensory loss to the lower limbs Paralysis of lower limb muscle Rectal prolapse At least 90% of patients have a neuropathic bladder with disturbances of detrusor and sphincter muscle activity.

32. Spina Bifida O cculta Occulta in L atin means “Hidden” Mildest form of spina bifida. Incidence-10% There is a small defect or gap in one or more vertebrae of the spine. Spinal cord does not protrude. Spinal cord and nerves are normal.

33. Skin at the site of the lesion may be normal or it may have some hair growing from it,there may be a dimple in the skin, or a birth mark. Asymptomatic.

34. Spina bifida occulta Diastematotomyelia Lipomyelomeningocele Tethered filum terminale Anterior sacral meningocele Myelocystocele Caudal regression syndrome

35. D iastematomyelia Split cord malformation(SCM). Presents as tethered cord syndrome. Common-lower thoracic or upper lumbar spine. Most patients have midline cutaneous abnormality , but it does not necessarily correspond to the level of cleft. Kyphoscoliosis eventually develops. Symptoms -Back pain, gait disturbance , muscular atrophy , urologic complaints.

36. Type I SCM(Split cord malformation ) Consists of two hemicords seperated by a bony or cartilagenous median septum,with each housed in its own dural sheath. Type II SCM Consists of two hemicords enveloped in the same dural sheath , and seperated by a fibrous septum. Both are associated with tethering. Surgery indicated for progressive neurological deficit and scoliosis.

37. L ipomyelomeningocele Here lipomatous tissue inserts into the conus , and herniates through the bony defect dorsally to attach to a subcutaneous mass. Two varieties One that inserts caudally into the conus,and One those attach to dorsal surface of spinal cord.

38. Tethered Filum T erminale Filum terminale gets thickened and adhered to the spinal canal. Failure of ascent of spinal cord during growth. Leads to A rnold C hiari malformation(type I), syringomyelia , scoliosis,incontinence . Diagnosis -MRI T reatment -Division of filum terminale to release the tension in spinal cord.

39. Caudal regression syndrome Heterogenous costellation of congenital caudal anomalies affecting the caudal spine and spinal cord, the hindgut ,the urogenital system, and the lower limbs. Partial agenesis of the thoracolumbosacral spine, Imperforate anus, Malformed genitalia, Bilateral renal dysplasia or aplasia, Pulmonary hypoplasia , and Extreme external rotation and fusion of the lower extremities( syringomyelia ).

40. Caudal Regression S yndrome Welch and A terman classified congenital sacral anomalies into 4 distinct clinical types. 1. A non-familial type associated with maternal diabetes mellitus showing complete absence of the sacrum and lower vertebrae with multiple congenital anomalies. 2. Agenesis of the distal sacral or coccygeal segments. 3. Hemisacral dysgenesis with presacral teratoma and 4. Hemisacral dysgenesis with anterior meningocele . Autosomal dominant inheritance was suggested for the last three types.

41. Caudal regression syndrome

42. C omplications Factors that affect severity of complications include : The size and location of the neural tube defect. Whether skin covers the affected area. Whether spinal nerves come out of the affected area of the spinal cord. Children with myelomeningocele may experience physical and neurological problems,including lack of normal bowel and bladder control, and or partial or complete paralysis of their legs.

43. Physiological changes below the lesion Abnormal nerve conduction resulting in Somatosensory losses Motor paralysis, including loss of bowel and bladder control Abnormal nerve conduction resulting in Changes in muscle tone Note - M uscle tone can range from flaccid to normal to spastic ; may have UMN signs with/without true spastic paraperesis . P rogression of neurologic dysfunction or change in neurologic status more concerning.

44. Anatomical changes below the lesion Musculoskeletal deformities(scoliosis) Joint and extremity deformities(joint contractures ,club foot, hip subluxations, diminished growth of non-weight bearing limbs) Osteoporosis Abnormal or damaged nerve tissue.

45. Other medical problems that occur Hydrocephalus(70-90%) Chiari II malformation(change the brain’s position) Tethered spinal cord(held in place by connective tissue) Urinary tract disorders Latex allergy(73%) Learning disabilities(20%)

46. Prsenting Symptoms and Signs of Occult S pinal D ysraphism Symptoms/signs incidence Foot deformity 39% Scoliosis 14% Gait abnormality 16% Leg weakness 48% Sensory abnormality 32% Urinary incontinence 36% Recurrent urinary tract infections 20% Fecal incontinence 32% Cutaneous abnormality 48%

47. Screening and D iagnosis ( 1) Blood tests Second trimester maternal serum alpha fetoprotein(MSAFP) Alpha- feto protein(AFP) is made naturally by the fetus and placenta. But if abnormally high levels of this protein appear in the mother’s bloodstream it may indicate that the fetus has a neural tube defect. The MSAFP test, however, is not specific for spina bifida(positive predictive value 2-4%).

48. (2) Ultrasound An advanced ultrasound can also detect signs of spina bifida(sensitivity 96%,specificity 100%) (3) Amniocentesis An analysis indicates the level of AFP present in the amniotic fluid. A small amount of AFP is normally found in amniotic fluid. When an open neural tube defect is present , the amniotic fluid contains an elevated amount of AFP because the skin surrounding the baby’s spine is gone and AFP leaks into the amniotic sac. ( 4) M RI

49. MRI showing occipital encephalocele

50. MRI showing lipomeningomyelocele

51. Treatment There is no cure for spina bifida. The nerve tissue that is damaged or lost cannot be repaired or replaced. Treatment depends on the type and severity of the disorder. Children with the mild form need no treatment. Moderate to severe cases, surgical closure of back lesion within 6 months.

52. There is no known cure for nerve damage caused by spina bifida. To prevent further damage of the nervous tissue and to prevent infection , surgeon operate to close the opening on the back. The spinal cord and its nerve roots are placed back into the spinal canal and covered with meninges.

53. In addition , a shunt may be surgically installed to provide a continuous drain for the excess CSF produced in the brain , as happens with hydrocephalus.

54. Surgery for meningomyelocele A.Position of the patient on the operating table ad an elliptical incision at the junction of the membrane and the skin.

55. B.Membrane being eplised to free the neural plaque.

56. C.Plaque lying in the dural layer

57. D.Dura is closed with a continuous suture

58. E.Skin is closed with interrupted sutures.

59. Surgery for L ipomeningocele

60. Surgery for D iastematomyelia

61. Surgery for Anterior Sacral M eningocele

62. Physical Therapy M anagement Pre-closure ROM assessment,therapeutic positioning for sleeping. Post-closure S ensory assessment , home programme instruction(ROM exercises, handling and carrying positions, and therapeutic positioning for sleeping).

63. N ewborn Therapeutic positioning pre- and post-surgery for repair of myelomeningocle . Keep an eye out for shunt malfunction.

64. The Young T oddler Typically seen in a transdisciplinary management of multiple and varied medical, surgical needs,and therapeutic needs. Transdisciplinary teamwork enhances communication ,prevents delays in care, coordinates management. Transdisciplinary team consists of ;Neurosurgeon,Orthopedician,Urologist,Physiotherapist,Nurse,Social worker, and may include others.

65. Concerns for the Y oung T oddler Developmental delay D elayed and abnormal head and trunk control, righting,and equillibrium responses. Handling/Positioning T he child needs to develop upright head control in many positions.

66. Structural Problems:Club F oot Congenital deformity with the following components; Adductus Equinus Varus,and Medial rotation

67. Bilateral talipus deformities of feet

68. Structural Problems:Sloppy K nees Low lumbar paralysis; “sloppy knees”from absent lateral hamstrings(and active medial hamstrings and quadriceps).

69. Orthoses and Equipment T ypical for Children with S pina B ifida Total contact arthrosis HKAFO(hip-knee-ankle-foot- orthosis A-frame (Toronto standing frame) Roliator walker Parapodium ( orlau swivel walker) Floor reaction AFO( A.K.A.anti -crouch arthrosis ) Start cart Articulating ankle joints in S1-level lesions Reciprocating gait orthosis ( new isocentric RGO) Twister cables

70. Example of P arapodium Commonly used for children with high lesions(T12-L3) Offers support to the hips, knees,and ankles.

71. The Activities for the Young T oddler Stimulate automatic balance responses against gravity in all positions to activate responses in t he lower extremities. Encourage brief periods of well-aligned weight-bearing throughout the day to stimulate acetabular development(reducing likelihood for hip dysplasia) and prevent osteoporosis. Avoid infant walkers,jumper seats, swings, bouncer chairs, excessive use of infant car seats.

72. The A dolescent Psychosocial issues Dependency on parents or caretakers Poor hygiene form lack of independence and motivation Need for vocational training Loss of “cure fantasy”during adolescence

73. Wheelchair I ssues Many disagree with the statement that the family should wait until the child age of 5 or 6 yrs to obtain the first wheelchair. Consider the child’s health and quality of life with and without wheelchair. Consult with the family and interdisciplinary team experts(physicians, seating clinical staff, physiotherapist with seating experience,vendors ) before making wheelchair decisions. Errors are costly.

74. The A dult Need to focus on health promotion and fitness. Watch for overuse syndrome, especially in upper extremities a nd also, low back pain. Monitor for safe and properly fitting equipment (wheelchair, bathroom devices, supportive and protective shoes). Model advocacy to improve access to community based resources.

75. The Adult Need to change the status quo Despite 21 st century medicine and treatment advances, many children with spina bifida never achieve independence - Many never marry , never live away from parents. There is not necessarily correaltion between the level of independence and level of lesion.

76. P revention Folic acid reduces the risk of having a child with a neural tube defect,such as spina bifida. Dose-400micrograms daily. Source-dark green vegetables,egg yolks,fruits like orange.

77. P rognosis Spina bifida is a : Static Nonprogressive defect. With worsening from secondary problems. The prognosis for a normal life span is generally good for a child with good habits and a supportive family caregiver.

78. Take H ome Message Due to folic acid intake 70% of cases are not seen now-a days. There is no known cure for nerve damage caused by spina bifida . Role of physiotherapy is important in spina bifida patients.

79. R eferences 1.Principles of Neurosurgery by S etti S.Rangachari 2.Pediatric S urgery by P rem P uri and M ichael H ollwarth 3.Human Embryology by I nderbir singh-7 th edition 4.Rob and Smith’s pediatric surgery 5.Avery’s Diseases of the newborn-9 th edition 6.Langman’s Embryology-12 th edition 7.Bailey and Love Short P ractice of Surgery -26 th edition