MYELOMENINGOCELE.pptx

MYELOMENINGOCELE

1. MYELOMENINGOCELE Dr. RUTAYISIRE François Xavier PGY1 Common surgical conditions module University of Rwanda Lecturer: Prof. Ntaganda Edmond

2. Definition Myelomeningocele: A c ongenital defect in vertebral arches with cystic dilatation of meninges and structural or functional abnormality of spinal cord or cauda equina. A type of Spina bifida

3. Epidemiology/genetics Incidence of myelomeningocele(MMC) is 1 – 2/1000 live births (0.1 – 0.2%). Risk increases to 2 – 3% if there is one previous birth with MMC, and 6 – 8% after two a ff ected children. The risk is also increased in families where close relatives (e.g. siblings) have given birth to MMC children, especially when on the mother ’ s side of the family. Prenatal folate (in the form of folic acid) lowers the incidence of MMC Incidence may increase in times of war, famine or economic disasters, but it may be gradually declining overall. Additionally, higher incidence rates were reported in females, increased maternal age, and lower socioeconomic status. Considering ethnicity, Latins were the most affected population in the united states.

4. Etiology The etiology behind myelomeningocele is often multifactorial. Environmental, maternal, and genetic factors. Environmental factors: exposure to radiation, pesticides, organic solvents, and teratogens. Maternal factors: irregular maternal nutrition, low folic acid supplementation, caffeine and alcohol consumption, smoking, the use of anticonvulsants, in addition to certain maternal illnesses such as diabetes, obesity, hyperthermia, and anxiety. Genetic factors: However, most of the cases of myelomeningocele are sporadic in origin and occur in a non-genetic pattern. Though, some genetic factors might increase the risk of occurrence, for instance, the presence of chromosomal anomalies of trisomy 18 or 13 and patients with an affected twin or first-degree relative.

5. Embryology Spina bifida is caused by the failure of the neural tube to close during the first month of embryonic development (often before the mother knows she is pregnant). Under normal circumstances, the closure of the neural tube occurs around the 23rd (rostral closure) and 27th (caudal closure) day after fertilization.

6. Clinical features The presentation of a newborn in the postnatal period: Presence of a sac extending from the vertebral column, covered with meninges, filled with cerebrospinal fluid and neural tissue. Signs of Neurogenic bladder, paraplegia, sphincter dysfunction, motor and sensory impairments in which they all can deteriorate with age. abnormal sexual development in adulthood. The clinical presentation is dependent on the site of the spinal lesion at the vertebral column. The higher the level affected, the more deficits occur, and the worse the prognosis of the patient.

7. Paralysis below Findings T12 complete paralysis of all muscles in LL L1 weak to moderate hip flexion, palpable contraction in sartorius L2 strong hip flexion and moderate hip adduction L3 normal hip adduction & almost normal knee extension L4 normal hip adduction, knee extension & dorsiflexion/inversion of foot; some hip abduction in flexion L5 normal adduction, flexion & lateral rotation of hip; moderate abduction; normal knee extension, moderate flexion; normal foot dorsiflexion; hip extension absent; • produces dorsiflexed foot and flexed thigh S1 normal hip flexion & abduction/adduction, moderate extension and lateral rotation; strong knee flexion & inversion/eversion of foot; moderate plantarflexion of foot; extension of all toes, but flexion only of terminal phalanx of great toe; normal medial & lateral hip rotation; complete paralysis of foot intrinsic (except abductor and flexor hallucis brevis); • produces clawing of toes and flattening of sole of foot S2 difficult to detect abnormality clinically; • with growth this produces clawing of the toes due to weakness of intrinsic muscles of sole of foot (innervated by S3) Findings in various levels of MMC lesion

8. Hydrocephalus in myelomeningocele Hydrocephalus (HCP) develops in 65 – 85% of patients with MMC, and 5 – 10% of MMC patients have clinically overt HCP at birth. Over 80% of MMC patients who will develop HCP do so before age 6 mos. Most MMC patients will have an associated Chiari type 2 malformation. Closure of the MMC defect may convert a latent HCP to active HCP by eliminating a route of egress of CSF. Latex allergy in myelomeningocele Up to 73% of MMC patients are allergic to proteins present in latex. The allergy is thought to arise from early and frequent exposure to latex products during medical care for these patients, and there is a suggestion that latex-free surgery on these infants may reduce the risk of the development of latex allergy

9. Diagnosis The diagnosis of myelomeningocele is possible in the first trimester of pregnancy. Amniocentesis is helpful and usually favored for high-risk patients. Ultrasonography is non-invasive, safe, effective, and often used for second-trimester anomaly scanning. The vertebra can be visualized by 12 weeks of gestation, and defects in closure of the vertebral arches can be detected. Fetal karyotyping and magnetic resonance imaging (MRI) could also be an option if the tests were not sufficient for the diagnosis.

10. Management Once the diagnosis has been made, early surgical repair of the spinal lesion is essential in preventing further deficits and neurological damage. Prenatal surgery was proven to be more effective than postnatal surgery in lowering the occurrence of future complications. Experimental treatment for the defect is to perform surgery in utero as early as 22 weeks of gestation. The fetus is exposed by an incision into the uterus, the defect is repaired, and the infant is placed back in the uterus.

11. Assessment and management of lesion ● M easure size of defect ● A ssess whether lesion is ruptured or unruptured ○ R uptured: start antibiotics (discontinue 6 hrs after MMC closure, or continue if shunt anticipated in next 5 or 6 days) ○ U nruptured: no antibiotics necessary ● C over lesion with Vaseline gauses , then sponges soaked in lactated ringers or normal saline (form a sterile gauze ring around the lesion if it is cystic and protruding) to prevent desiccation ● Trendelenburg position, patient on stomach (keeps pressure o ff lesion) ● perform surgical closure within 36 hrs unless there is a contraindication to surgery (simultaneous shunt is not usually done except if overt hydrocephalus (HCP) at birth).

12. Post-natal surgery:- Closure of the Myelomeningocele is performed immediately afterbirth if external CSF leakage is present and typically within the first 24-48 hours in the absence of CSF leakage. Multidisciplinary interventions needed to prevent progressive deterioration of multiple body systems Treatment team consists of pediatric specialists in ◦ Physical medicine and rehabilitation ◦ Neurosurgery ◦ Urology ◦ Orthopedics along with ◦ Pediatric nursing ◦ Physical therapy ◦ occupational and recreational therapy ◦ psychology and ◦ medical social work

13. Prevention Prevention of many NTDs is possible if women take folic acid [400 pig/day] starting at least 1 month prior to conception and then throughout their pregnancy. Such a protocol reduces the occurrence of NTDs by as much as 50% to 70%. Because approximately 50% of all pregnancies are unplanned, it is recommended that all women of childbearing age take a multivitamin containing 400 ug of folic acid daily. Furthermore, women who have had a child with an NTD or who have a family history of NTDs should take 400 pg of folic acid daily and then 4,000 pg [4 mg] per day starting at least 1 month before conception through the first 3 months of pregnancy. The birth prevalence of NTDs in the United States has decreased by approximately 25% to 1/1,500 births because fortification of flour with folic acid was instituted in 1998.

14. References Mark S. Greenberg, Handbook of Neurosurgery 9th edition Langman’s Medical Embryology 14 th edition Alruwaili AA, M Das J. Myelomeningocele. [Updated 2021 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546696/

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