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Lumbar Myelomeningocele
Lumbar Myelomeningocele FRANC D. INGRAHAM, M.D., F.A.C.S.* FRED D. FOWLER, M.D.**
M YELOMENINGOCELES are the most common congenital anomalies of the nervous system, occurring in about 0.25 per cent of all births. They are caused by failure of fusion of the dorsal lips of the neural groove during the formation of the neural tube. 1 This normally occurs between the third and fourth weeks of gestation. Fusion begins near the midportion of the embryo and progresses anteriorly and posteriorly, the ends of the tube being the last regions to close. These malforma -ions may occur at any level of the cerebrospinal axis, but approximately 85 per cent involve the lumbar region of the spine. Such a lesion typically appears as a midline, saclike protuberance overlying a defect in the dorsal elements of the spinal column. It has an epithelial covering which may vary from normal skin to only a few cells in thickness. Occasionally the spinal cord itself may be spread out under the surface of the sac, but more often nerve elements can be seen through the translucent wall either directly or by transillumination. The surrounding skin is sometimes abnormal-having vascular malformations or unusual hair growth. The subcutaneous fat may be greatly thickened and, in some instances, may form the bulk of the mass. If these features are present there is no problem of diagnosis, although rarely a teratoma or lipoma may have a similar appearance. The occurrence of a myelomeningocele in a baby is naturally a matter of great concern to the parents. There is frequently apprehension about having similar difficulty with subsequent children. There is also often a feeling of guilt in the parent's attitude partially because they wonder if they are to blame in any way for the deformity and partially because they may have conscious or subconscious desires to reject the deformed
* N eurosurgeon-in-Chief, Children's Medical Cenier; Neurological Surgeon, Peter Bent Brigham Hospital; Associate Professor of Surgery, Harvard Medical School, Boston.
** Neurosurgical Resident, Children's Medical Center; Resident in Neurological Surgery, Peter Bent Brigham Hospital; Teaching Fellow in Surgery, Harvard Medical School, BObion. 1569
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infant. It is best to reassure them on these matters because, although there is a possibility of a second child having similar defect (1 :30), the probability is in favor of it being normal.2 Six per cent of patients who have a myelomeningocele have a positive family history of a similar malformation. 3 EXAMINATION OF THE PATIENT
In examining a patient with a myelomeningocele the extent and size of the malformation should be .noted. Observations are made on the epithelial covering, taking particular care to look for leakage of cerebrospinal fluid. If there has been much loss of fluid the sac will frequently be collapsed. Infected or macerated skin should receive prompt attention in order to prevent breakdown of the epithelial covering and contamination of the cerebrospinal fluid. The lesion is transilluminated in order to evaluate the amount of tissue contained within the meningeal sac. Careful neurologic examination will reveal the extent of functional damage to the nervous tissue. As it is the lower end of the spinal cord and the roots of the cauda equina that are predominantly damaged, the motor deficit is a flaccid paralysis with loss of the normal reflexes. Cutaneous sensation may also be absent in the involved segments. This is easily determined even in small infants, and all areas including the perianal region should be carefully tested with a pin. Anal and vesical function are evaluated by observing whether the sphincter tone is relaxed when the child cries or strains. The abdomen is examined for bladder distention. It is also noted whether the child voids in a stream or if there is continuous dribbling of urine. Hydrocephalus may be associated with a myelomeningocele and therefore serial head circumference measurements are very important. The size and degree of tenseness of the anterior fontanelle as well as the distention of the scalp veins may give some indication of increasing intracranial pressure. Other congenital anomalies may also be present and therefore a careful evaluation of the child's general condition is essential. ASSOCIATED CONDITIONS
Hydrocephalus
The Arnold-Chiari malformation is frequently present in patients with lumbar myelomeningoceles and mayor may not lead to symptomatic hydrocephalus. This malformation is considered to be an anomaly associated with, rather than caused by, the myelomeningocele and consists of congenital adhesions between the cerebellum and the brain stem with protrusion of abnormal cerebellar tissue through the foramen magnum.' This may produce some degree of obstruction of normal circulation of cerebrospinal fluid and cause either a communicating or noncommunicating hydrocephalus, depending on whether the foramen of Magendie remains patent. It is frequently found that, although the hydro-
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cephalus may be initially communicating, treatment by means of a lumbar shunt into the peritoneal cavity can lead to further herniation of the cerebellum through the foramen magnum and eventually produce occlusion of all the foramina of the fourth ventricle. Thus the child's hydrocephalus progresses, and if it is restudied at this time it is found to be noncommunicating. Surgical treatment of hydrocephalus of this type is therefore not a simple matter, and the indications for it must be carefully considered. Meningitis
Meningitis may occur subsequent to surface contamination or it may be associated with leakage of cerebrospinal fluid. The organism is usually either E. coli from fecal contamination or staphylococcus from the skin. The infection may lead to death in a debilitated child if there is not a prompt response to antibiotic therapy. In some cases, even though the meningitis is cured, there may be residual obstruction of cerebrospinal fluid circulation due to arachnoiditis. Musculoskeletal Disorders
Partial paralysis of the lower extremities may produce muscular imbalance with resulting joint deformity. This can usually be helped by manipulation if treated early, but if left untreated will lead to fixed contractures of muscles, ligaments and joint capsules. Parents should be instructed in simple passive exercises that can be done at home. Night splints or, in the more severe cases, leg casts may be of value. In general, it is wise not to embark on more elaborate orthopedic treatment such as tendon transplantation and joint stabilization until the children are four or five years old. Even at this age operation should be done only after waiting long enough for the pattern of muscle power and bahnce to beoome stationary. It is difficult to get a precise evaluation of these factors in very small children and ill-advised procedures may sacrifice some potentially useful muscle power and make additional corrective surgery necessary as the child gets older. Trophic Changes
The loss of sensation makes the skin subject to breakdown and ulceration with minimal trauma. It is therefore essential to have the skin examined by the family at frequent intervals and remove all pressure from areas of early ulceration. Particular attention to keeping the patient dry will help prevent skin maceration and decubitus formation. Bowel and Bladder Incontinence
In most cases of lumbar myelomeningocele there is loss of control of the bladder and bowel sphincters. Bowel control is usually no great prob-
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lem when the children get older as it can usually be regulated by dietary intake, with occasional use of suppositories or enemas. Urinary incontinence is, however, a major consideration in the care of these patients. The efforts to deal with this difficult and important problem were well summarized by Gross 5 in 1953. It is best not to attempt any major urological procedures until the child is at least five or six years old because every chance for spontaneous improvement must first be given. During this period of waiting the patient may be given exercises to strengthen the bladder sphincter if function is present at all. Frequently there will be some improvement during this time. In some instances it is advisable to institute constant catheter drainage to prevent progressive damage to the upper urinary tract. If the child does not obtain voluntary control, other procedures such as bladder neck resection, wet colostomy, or permanent suprapubic cystotomy may be considered. As there is no ideal solution to this problem, both the patient and the parents must be prepared for the results and possible consequences of such procedures. It is important to evaluate the upper urinary tract by intravenous urography at some time during early childhood, especially if there are signs of urinary tract infection or renal dysfunction. Chronic bladder sepsis associated with ureterovesical sphincter incompetence may lead to hydronephrosis and pyelonephrosis. Such complications are not an uncommon cause of death in these patients. CONSIDERATIONS IN TREATMENT
In view of the many complicating factors, the wisest approach to the treatment of the myelomeningocele is conservative. Of course, in the simple meningocele with a small base, operation may be done during the first month or two of life without any difficulty. At the other extreme, a child with an extensive lesion and complete paraplegia who is developing hydrocephalus should not be considered for surgical intervention at all. The majority of patients will fall somewhere between these two groups and the optimal time for operation must be selected individually in each case. Several factors must be borne in mind in making this decision. In the infant with a large sessile myelomeningocele the feasibility of an operation requires careful consideration. The closure of the skin over the defect remaining after the excision of such a mass may present a difficult problem. Subjecting a young infant to a major surgical procedure involving raising of skin flaps, grafting, and prolonged anesthesia may be a rather hazardous undertaking. As the child becomes older not only is he a better operative risk but there is more skin available for an adequate primary closure. Operation does not as a rule improve the neurologic function of these children. The loss of function is primarily on the basis of embryologic
Ji.;;
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malformation of nervous tissue. This cannot be restored by mere removal of the meningocele sac. Indeed, if care is not taken in removing these lesions it is possible to produce additional neurologic defect by operative intervention. Occasionally, slight improvement may result from release of traction on the spinal cord and involved nerve elements, hence these should be freed completely at the time of operation. 6 The presence of hydrocephalus is of vital concern in evaluating these patients. If the cerebral cortex has been extensively damaged due to hydrocephalus, an operation should not be attempted unless as the child develops there are signs that he will have sufficient mentality for some degree of training. It is dubious whether the survival of a paraplegic, mentally defective and possibly blind child can be considered as a satisfactory result by either the patient, the parents or society in general. Because of these considerations a period of observation is extremely helpful in evaluating the possibility for successful rehabilitation except when the lesion is quite small and the child has minimal local neurologic involvement and no signs of hydrocephalus. The parents are carefully instructed in the care of the meningocele and the child is seen at intervals and examined as outlined above. Consultation with orthopedists and urologists should be carried out as indicated in order that all facets of the child's problem receive adequate attention. CARE OF THE MYELOMENINGOCELE
While waiting until the patient is ready for surgical treatment it is important that proper care be taken of the lesion. Those patients with a good skin covering need little special attention. It is more common, however, for them to have a thin epithelial layer which is subject to infection and ulceration if not managed properly. As it may be necessary to care for the lesion for a number of months, the family should be shown the dressing technique and, preferably, be given written instructions. A very satisfactory type of dressing which may easily be kept clean and which protects the myelomeningocele from trauma may be made from a sheet of Cilkloid, a soft ring of covered sponge rubber or cotton, and gauze sponges. The instructions given to the parents are as follows: 1. This is a clean, but not a sterile procedure. Hands should be washed for 2 minutes in soap and water before changing the dressing. 2. The meningocele and surrounding skin are washed gently with 1 :1000 aqueous Zephiran (boric acid solution made with 1 teaspoonful of boric acid to 1 pint of boiled water may be used in place of Zephiran). If the Cilkloid is to be changed it should be thoroughly moistened with Zephiran before being carefully peeled away in order not to injure the delicate skin covering. 3. A square of Cilkloid (perforated plastic sheet) is soaked for at least 1 hour in rubbing alcohol (70 per cent ethyl or 50 per cent isopropyl alcohol) and then rinsed in aqueous Zephiran. This is then used to cover the meningocele and
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3-inch sterile gauze squares are put over it to absorb any exudate which may form (Fig. 511, A) 4. A doughnut-shaped ring is made from a length of sponge rubber or absorbent cotton covered with gauze bandage. This should be large enough to fit around the base of the meningocele and be high enough to come to the top of the lesion. 5. The ring is placed in position and held in place with a flannel binder or a soft diaper wrapped around the baby and fastened snugly with safety pins (Fig. 511, B).
Fig. 511. Meningocele dressing technique. A, Sterile Cilkloid is placed over the lesion and then covered with 3 inch gauze squares. B, A padded ring is used around the myelomeningocele to protect it from trauma. This is held in place with a binder fastened with safety pins.
6. The gauze flats are changed once a day (or more often if soiled). When changing them it is best to wet the gauze with a little aqueous Zephiran before lifting them off if they are adherent. The Cilkloid needs to be changed only about once a week unless the lesion has been grossly contaminated.
The parents should be assured that with proper care there is little chance of the sac rupturing. This does occasionally occur, however. In
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this situation it is usually wise to have the child in the hospital. Dressings are done as outlined above, but special care is used to maintain a sterile dressing technique. The patient is put on a Bradford frame and restrained in the prone position. No diapers are used and a ring is not necessary. The child is given antibiotics. Occasionally moist saline dressings are useful for a day or two in order to promote epithelial closure of the sac.
Fig. 512. Patient positioned for operation. A, Endotracheal tube. B, Polyethylene catheter for intravenous infusion. C, Rolls under the hips and shoulders. D, Plastic sheet over the buttocks. E, Plate for electrocautery. F, Burette for intravenous infusion.
Rupture of the sac is frequently secondary to increased pressure within the meningocele due to progressing hydrocephalus. Under these circumstances it is sometimes of value to use ventricular drainage for a time to reduce the cerebrospinal fluid pressure while the meningocele is healing. 7 It must be remembered, however, that such treatment may lead to prolonged hospitalization because the child may not tolerate being taken off drainage without first having some form of shunt procedure. This, as has been mentioned above, may be difficult to do :mccessfully.
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Franc D. Ingraham, Fred D. Fowler OPERATIVE TREATMENT
Surgical treatment should usually be delayed until the child is at least 12 to 18 months old. Operation is indicated for facilitation of care at home, and to help with orthopedic management. Rupture of the sac may necessitate operation if the leakage cannot otherwise be controlled. Recurrent meningitis due to skin organisms may indicate that the source of infection is through the sac wall and suggest the need for early removal. Once the decision has been made, the operation usually presents no serious difficulties. Endotracheal ether anesthesia is usually employed. A polyethylene tube is inserted into a peripheral vein for intravenous infusion during the operation. The child is placed in the prone position and rolls are put under the shoulders and hips in order that the chest and abdomen remain free and respirations are not hindered (Fig. 512). The table is adjusted so that the patient's head is slightly lower than his buttocks. This helps prevent excessive loss of cdrebrospinal fluid during the operation. After preparing the back a sterile plastic drape is placed below the lower end of the opeartive field to wall off the buttocks and anus. The back should be draped widely so that adequate skin may be mobilized for the closure if necessary. In the smaller lesions an elliptical skin incision may be made about the base down to the deep fascia and dissection carried around the neck of the dural sac (Fig. 513). The dura is then opened over what appears to be a thin area without underlying nervous tissue. This incision should be made as far away from the spinal canal as possible in order that there may be enough dura left to permit closure. The cutaneous portion of the sac is then inverted and any nerve elements which may be adherent in the inner wall are carefully dissected away. Some of the nerves may loop into the meningocele and return to the spinal canal and thence to the extremities. A nerve stimulator may be used to give some indication of which of these nerves may be intact, but if the child has any function below the level of the lesion it is better to preserve carefully all the nervous tissue that is present. Great care must be used to prevent contamination of the subarachnoid space with blood as this may lead to meningeal irritation and potentiate the development of postoperative hydrocephalus. It is not necessary to save the sac or to imbricate it because any possible resorptive capacity of the lining seems to have little if any effect on the occurrence of hydrocephalus. It is, however, possible to precipitate hydrocephalus by the sudden loss of large amounts of cerebrospinal fluid when the dura is opened. This causes acute coning of the cerebellar tissue in the ArnoldChiari malformation and subsequent interference with the established balance of cerebrospinal fluid circulation. The dura should be closed if at all possible. This closure is done with interrupted sutures and an attempt made to prevent any leakage of
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Fig. 513. Operative technique for myelomeningocele. A, Incision outlined (for large lesions the incisions are extended up and down at the lateral extent and the shaded area is undermined). B, The dissection is carried around the base of the lesion exposing the dura inside the spinal canal. C, The dura exposed and the sac held up with Allis forceps. D, The dura is incised showing the end of the spinal cord and nerve elements within. E, The sac is inverted over the operator's finger and the nervous tissue dissected away with a scalpel. F, The cord and nerve roots are replaced within the spinal canal and the dura sutured together. G, A lateral fascial flap may be brought over from either one or both sides to cover the spinal defect. H, Skin flaps may be rotated to get a primary suture without tension if there is a large defect in the skin.
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cerebrospinal fluid through the suture line. This may be checked by having the anesthetist exert gentle pressure on the anterior fontanelle or on the jugular veins while the suture line is under direct observation. If there is functioning nervous tissue remaining in the spinal canal and dural closure would cause undue compression, it is better to leave the dura open and to swing lateral fascial flaps to cover the spinal canal. This gives some protection to the nerve elements and also helps to seal off the subarachnoid space. Nonabsorbable suture material such as silk or stainless steel wire is used throughout the closure. The lesions with a relatively small base can as a rule be closed quite easily. Those which are larger, however, have to be closed by turning flaps from above and below (Fig. 513, H), or by using relaxing incisions. Whatever method is used, it is essential that there be no tension on the suture line in the midportion ofthe wound overlying the spinal defect. Good skin approximation is also important because primary wound healing is a major factor in decreasing the length of hospitalization. In the treatment of lipomyelomeningoceles there are certain special considerations. It is important not to be too radical in removing such lesions. The fat, which is usually a large mass surrounding the nerve elements, may extend directly into the spinal cord itself and must be removed cautiously. Operation for this type of lesion is frequently for cosmetic reasons as the skin covering is usually good. It must be remembered that the 0peration will not in most instances improve nerve function even though the lipomatous portion may extend into the spinal canal and widen it. This fatty tissue is not actively expanding, but is present merely as a congenital remnant. Therefore only tissue which is easily removable should be excised. In the region of the causa equina where nerves are intermingled with tough fibrous strands and lipomatous tissue it is best to leave all deeper structures strictly alone as it is very easy to harm the child by attempting a complete removal. On occasion it is proper to operate on a child in the presence of an early progressive hydrocephalus if the mental function is still good and the local neural involvement is not marked. These children usually have some degree of involvement of the bladder sphincter and are subject to urinary tract infection and thus the ureteral shunt procedure cannot be safely used. If the child can be shown to have a communicating type of hydrocephalus preoperatively it is possible, however, to put in a sub- . arachnoid-peritoneal shunt at the time of removal of the meningocele. A small laminectomy is made just above the spina bifida. The dura is incised and a small hole made in the araehnoid membrane through which a No. 18 polyethylene tube is passed upwards into the thoracic subarachnoid space for a distance of 3 or 4 cm. A lateral incision is then made in the flank (or it is sometimes possible to expose the abdominal
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muscles through the back incision if large skin flaps are being turned) and the mUlilcles split in the direction of their fibers until the peritoneum is exposed. The tube is then passed subcutaneously or through the muscle between the two incisions and then inserted through a small opening into the peritoneal cavity. POSTOPERATIVE CARE
Except for those children with a very small and easily closed incision, the patient is positioned on a Bradford frame postoperatively (Fig. 514). The frame is covered with plastic sheeting and tilted so that the child's head is slightly lower than the buttocks, thereby reducing the cerebrospinal fluid pressure at the site of the dural closure. The patient's legs are
Fig. 514. Postoperative care on the Bradford frame.
restrained in the extended position to prevent flexion at the hip and possible distraction of the wound edges. No diapers are used and a hole is left in the center of the frame under which a bedpan may be placed. A plastic drape is stuck to the skin of the buttock just below the dressing and is brought over the dressing to act as a water-proof shield to protect the wound from contamination. Blankets may be put over a supporting frame to keep the child warm. These should not lie on the buttocks or wound, however. If the meningocele is large and there has been much loss of cerebrospinal fluid during the procedure, or if the child has any evidence of hydrocephalus, ventricular drainage should be instituted shortly after the operation. There may be sudden increase in intracranial pressure postoperatively if this is not done. The drainage tube is usually placed
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Franc D. Ingraham, Fred D. Fowler
at a height of 100 mm. and, starting on the second or third day, it is gradually raised over a three day period to a height of 250 mm. At this time, if there is no obstruction to the cerebrospinal fluid circulation, the amount of fluid drained off will be less than 50 cc. a day. The tube may then be clamped off for 24 hours and if this iR well tolerated by the child it can be removed. If the drainage does not decrease it may indicate that the cerebrospinal fluid pathways are obstructed. In spite of this the fluid circulation may eventually come into equilibrium and therefore it is usually wise to wait up to two or three weeks (changing the site of the drainage tube after ten days) in an attempt to avert the necessity for a shunting procedure. If in spite of these measures the child continues to run an elevated pressure, a posterior fossa decompression or a peritoneal shunt from either the ventricle or the lumbar region will have to be considered. The children are maintained on streptomycin for four days and penicillin throughout the postoperative period. It is necessary to inspect the wound on the day after operation to see whether any fluid has collected. This is prone to occur when the dura has not been closed or if extensive skin flaps have been mobilized. It is essential if fluid has accumulated that this be aspirated as often as necessary to keep the wound flat because the increased pressure caused by its presence may be sufficient to produce necrosis of the skin edges at the center of the incision. Sutures are left in for eight to 14 days to insure firm wound healing. Following removal of the sutures the patient may be taken off of the Bradford frame. Although the care of these patients may involve the management of many problems, the final results in properly selected and treated cases can be most gratifying. It has been estimated that about 30 per cent of these patients may be effectively rehabilitated. With the techniques now available for paraplegic training it is therefore possible for even a badly crippled child to lead a comfortable and useful existence. It is the responsibility of the attending physician to decide with care which of these children are satisfactory candidates for surgical therapy. Once this has been done the patient must be seen at intervals thereafter and his general pbysical condition evaluated if optimal results are to be obtained. SUMMARY
The conservative management of lumbar myelomeningoceles is emphasized. The care of these lesions has been outlined with suggestions regarding the selection of patients for operation as well as techniques for operative management. Consideration has been given to the occurrence of hydrocephalus and other complicating factors in these patients and their treatment has been discussed.
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REFERENCES 1. Patten, B. M.: Embryologic Stages in the Establishing of Myelochisis with Spina Bifida. Am. J. Anat. 93: 365-395, 1953. 2. MacMahon, B., Pugh, T. F. and Ingalls, T. H.: Anencephalus, Spina Bifida, and Hydrocephalus Incidence Related to Sex, Race, Season of Birth, and Incidence in Siblings. Brit. J. Prevo & Social Med. 7: 211-219, 1953. 3. Ingraham et al.: Spina Bifida and Cranium Bifida. Cambridge, Harvard University Printing Office, 1943. 4. Russell, D. S.: Observations on the Pathology of Hydrocephalus (M.R.C. Report No. 265). London, His Majesty's Stationary Office, 1949. 5. Gross, R. E., Holcomb, G. W. Jr. and Swan, H.: Treatment of Neurogenic Urinary and Fecal Incontinence in Children. Arch. Surg. 66: 143-154, 1953. 6. Campbell, J. B.: Congenital Anomalies of the Neural Axis. Am. J. Surgery 75: 231-256, 1948. 7. Bering, E. A. Jr.: A Simplified Apparatus for Constant Ventricular Drainage. J. Neurosurg. 8: 450-452, 1951.
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M YELOMENINGOCELES are the most common congenital anomalies of the nervous system, occurring in about 0.25 per cent of all births. They are caused by failure of fusion of the dorsal lips of the neural groove during the formation of the neural tube. 1 This normally occurs between the third and fourth weeks of gestation. Fusion begins near the midportion of the embryo and progresses anteriorly and posteriorly, the ends of the tube being the last regions to close. These malforma -ions may occur at any level of the cerebrospinal axis, but approximately 85 per cent involve the lumbar region of the spine. Such a lesion typically appears as a midline, saclike protuberance overlying a defect in the dorsal elements of the spinal column. It has an epithelial covering which may vary from normal skin to only a few cells in thickness. Occasionally the spinal cord itself may be spread out under the surface of the sac, but more often nerve elements can be seen through the translucent wall either directly or by transillumination. The surrounding skin is sometimes abnormal-having vascular malformations or unusual hair growth. The subcutaneous fat may be greatly thickened and, in some instances, may form the bulk of the mass. If these features are present there is no problem of diagnosis, although rarely a teratoma or lipoma may have a similar appearance. The occurrence of a myelomeningocele in a baby is naturally a matter of great concern to the parents. There is frequently apprehension about having similar difficulty with subsequent children. There is also often a feeling of guilt in the parent's attitude partially because they wonder if they are to blame in any way for the deformity and partially because they may have conscious or subconscious desires to reject the deformed
* N eurosurgeon-in-Chief, Children's Medical Cenier; Neurological Surgeon, Peter Bent Brigham Hospital; Associate Professor of Surgery, Harvard Medical School, Boston.
** Neurosurgical Resident, Children's Medical Center; Resident in Neurological Surgery, Peter Bent Brigham Hospital; Teaching Fellow in Surgery, Harvard Medical School, BObion. 1569
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infant. It is best to reassure them on these matters because, although there is a possibility of a second child having similar defect (1 :30), the probability is in favor of it being normal.2 Six per cent of patients who have a myelomeningocele have a positive family history of a similar malformation. 3 EXAMINATION OF THE PATIENT
In examining a patient with a myelomeningocele the extent and size of the malformation should be .noted. Observations are made on the epithelial covering, taking particular care to look for leakage of cerebrospinal fluid. If there has been much loss of fluid the sac will frequently be collapsed. Infected or macerated skin should receive prompt attention in order to prevent breakdown of the epithelial covering and contamination of the cerebrospinal fluid. The lesion is transilluminated in order to evaluate the amount of tissue contained within the meningeal sac. Careful neurologic examination will reveal the extent of functional damage to the nervous tissue. As it is the lower end of the spinal cord and the roots of the cauda equina that are predominantly damaged, the motor deficit is a flaccid paralysis with loss of the normal reflexes. Cutaneous sensation may also be absent in the involved segments. This is easily determined even in small infants, and all areas including the perianal region should be carefully tested with a pin. Anal and vesical function are evaluated by observing whether the sphincter tone is relaxed when the child cries or strains. The abdomen is examined for bladder distention. It is also noted whether the child voids in a stream or if there is continuous dribbling of urine. Hydrocephalus may be associated with a myelomeningocele and therefore serial head circumference measurements are very important. The size and degree of tenseness of the anterior fontanelle as well as the distention of the scalp veins may give some indication of increasing intracranial pressure. Other congenital anomalies may also be present and therefore a careful evaluation of the child's general condition is essential. ASSOCIATED CONDITIONS
Hydrocephalus
The Arnold-Chiari malformation is frequently present in patients with lumbar myelomeningoceles and mayor may not lead to symptomatic hydrocephalus. This malformation is considered to be an anomaly associated with, rather than caused by, the myelomeningocele and consists of congenital adhesions between the cerebellum and the brain stem with protrusion of abnormal cerebellar tissue through the foramen magnum.' This may produce some degree of obstruction of normal circulation of cerebrospinal fluid and cause either a communicating or noncommunicating hydrocephalus, depending on whether the foramen of Magendie remains patent. It is frequently found that, although the hydro-
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cephalus may be initially communicating, treatment by means of a lumbar shunt into the peritoneal cavity can lead to further herniation of the cerebellum through the foramen magnum and eventually produce occlusion of all the foramina of the fourth ventricle. Thus the child's hydrocephalus progresses, and if it is restudied at this time it is found to be noncommunicating. Surgical treatment of hydrocephalus of this type is therefore not a simple matter, and the indications for it must be carefully considered. Meningitis
Meningitis may occur subsequent to surface contamination or it may be associated with leakage of cerebrospinal fluid. The organism is usually either E. coli from fecal contamination or staphylococcus from the skin. The infection may lead to death in a debilitated child if there is not a prompt response to antibiotic therapy. In some cases, even though the meningitis is cured, there may be residual obstruction of cerebrospinal fluid circulation due to arachnoiditis. Musculoskeletal Disorders
Partial paralysis of the lower extremities may produce muscular imbalance with resulting joint deformity. This can usually be helped by manipulation if treated early, but if left untreated will lead to fixed contractures of muscles, ligaments and joint capsules. Parents should be instructed in simple passive exercises that can be done at home. Night splints or, in the more severe cases, leg casts may be of value. In general, it is wise not to embark on more elaborate orthopedic treatment such as tendon transplantation and joint stabilization until the children are four or five years old. Even at this age operation should be done only after waiting long enough for the pattern of muscle power and bahnce to beoome stationary. It is difficult to get a precise evaluation of these factors in very small children and ill-advised procedures may sacrifice some potentially useful muscle power and make additional corrective surgery necessary as the child gets older. Trophic Changes
The loss of sensation makes the skin subject to breakdown and ulceration with minimal trauma. It is therefore essential to have the skin examined by the family at frequent intervals and remove all pressure from areas of early ulceration. Particular attention to keeping the patient dry will help prevent skin maceration and decubitus formation. Bowel and Bladder Incontinence
In most cases of lumbar myelomeningocele there is loss of control of the bladder and bowel sphincters. Bowel control is usually no great prob-
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lem when the children get older as it can usually be regulated by dietary intake, with occasional use of suppositories or enemas. Urinary incontinence is, however, a major consideration in the care of these patients. The efforts to deal with this difficult and important problem were well summarized by Gross 5 in 1953. It is best not to attempt any major urological procedures until the child is at least five or six years old because every chance for spontaneous improvement must first be given. During this period of waiting the patient may be given exercises to strengthen the bladder sphincter if function is present at all. Frequently there will be some improvement during this time. In some instances it is advisable to institute constant catheter drainage to prevent progressive damage to the upper urinary tract. If the child does not obtain voluntary control, other procedures such as bladder neck resection, wet colostomy, or permanent suprapubic cystotomy may be considered. As there is no ideal solution to this problem, both the patient and the parents must be prepared for the results and possible consequences of such procedures. It is important to evaluate the upper urinary tract by intravenous urography at some time during early childhood, especially if there are signs of urinary tract infection or renal dysfunction. Chronic bladder sepsis associated with ureterovesical sphincter incompetence may lead to hydronephrosis and pyelonephrosis. Such complications are not an uncommon cause of death in these patients. CONSIDERATIONS IN TREATMENT
In view of the many complicating factors, the wisest approach to the treatment of the myelomeningocele is conservative. Of course, in the simple meningocele with a small base, operation may be done during the first month or two of life without any difficulty. At the other extreme, a child with an extensive lesion and complete paraplegia who is developing hydrocephalus should not be considered for surgical intervention at all. The majority of patients will fall somewhere between these two groups and the optimal time for operation must be selected individually in each case. Several factors must be borne in mind in making this decision. In the infant with a large sessile myelomeningocele the feasibility of an operation requires careful consideration. The closure of the skin over the defect remaining after the excision of such a mass may present a difficult problem. Subjecting a young infant to a major surgical procedure involving raising of skin flaps, grafting, and prolonged anesthesia may be a rather hazardous undertaking. As the child becomes older not only is he a better operative risk but there is more skin available for an adequate primary closure. Operation does not as a rule improve the neurologic function of these children. The loss of function is primarily on the basis of embryologic
Ji.;;
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malformation of nervous tissue. This cannot be restored by mere removal of the meningocele sac. Indeed, if care is not taken in removing these lesions it is possible to produce additional neurologic defect by operative intervention. Occasionally, slight improvement may result from release of traction on the spinal cord and involved nerve elements, hence these should be freed completely at the time of operation. 6 The presence of hydrocephalus is of vital concern in evaluating these patients. If the cerebral cortex has been extensively damaged due to hydrocephalus, an operation should not be attempted unless as the child develops there are signs that he will have sufficient mentality for some degree of training. It is dubious whether the survival of a paraplegic, mentally defective and possibly blind child can be considered as a satisfactory result by either the patient, the parents or society in general. Because of these considerations a period of observation is extremely helpful in evaluating the possibility for successful rehabilitation except when the lesion is quite small and the child has minimal local neurologic involvement and no signs of hydrocephalus. The parents are carefully instructed in the care of the meningocele and the child is seen at intervals and examined as outlined above. Consultation with orthopedists and urologists should be carried out as indicated in order that all facets of the child's problem receive adequate attention. CARE OF THE MYELOMENINGOCELE
While waiting until the patient is ready for surgical treatment it is important that proper care be taken of the lesion. Those patients with a good skin covering need little special attention. It is more common, however, for them to have a thin epithelial layer which is subject to infection and ulceration if not managed properly. As it may be necessary to care for the lesion for a number of months, the family should be shown the dressing technique and, preferably, be given written instructions. A very satisfactory type of dressing which may easily be kept clean and which protects the myelomeningocele from trauma may be made from a sheet of Cilkloid, a soft ring of covered sponge rubber or cotton, and gauze sponges. The instructions given to the parents are as follows: 1. This is a clean, but not a sterile procedure. Hands should be washed for 2 minutes in soap and water before changing the dressing. 2. The meningocele and surrounding skin are washed gently with 1 :1000 aqueous Zephiran (boric acid solution made with 1 teaspoonful of boric acid to 1 pint of boiled water may be used in place of Zephiran). If the Cilkloid is to be changed it should be thoroughly moistened with Zephiran before being carefully peeled away in order not to injure the delicate skin covering. 3. A square of Cilkloid (perforated plastic sheet) is soaked for at least 1 hour in rubbing alcohol (70 per cent ethyl or 50 per cent isopropyl alcohol) and then rinsed in aqueous Zephiran. This is then used to cover the meningocele and
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Franc D. Ingraham, Fred D. Fowler
3-inch sterile gauze squares are put over it to absorb any exudate which may form (Fig. 511, A) 4. A doughnut-shaped ring is made from a length of sponge rubber or absorbent cotton covered with gauze bandage. This should be large enough to fit around the base of the meningocele and be high enough to come to the top of the lesion. 5. The ring is placed in position and held in place with a flannel binder or a soft diaper wrapped around the baby and fastened snugly with safety pins (Fig. 511, B).
Fig. 511. Meningocele dressing technique. A, Sterile Cilkloid is placed over the lesion and then covered with 3 inch gauze squares. B, A padded ring is used around the myelomeningocele to protect it from trauma. This is held in place with a binder fastened with safety pins.
6. The gauze flats are changed once a day (or more often if soiled). When changing them it is best to wet the gauze with a little aqueous Zephiran before lifting them off if they are adherent. The Cilkloid needs to be changed only about once a week unless the lesion has been grossly contaminated.
The parents should be assured that with proper care there is little chance of the sac rupturing. This does occasionally occur, however. In
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this situation it is usually wise to have the child in the hospital. Dressings are done as outlined above, but special care is used to maintain a sterile dressing technique. The patient is put on a Bradford frame and restrained in the prone position. No diapers are used and a ring is not necessary. The child is given antibiotics. Occasionally moist saline dressings are useful for a day or two in order to promote epithelial closure of the sac.
Fig. 512. Patient positioned for operation. A, Endotracheal tube. B, Polyethylene catheter for intravenous infusion. C, Rolls under the hips and shoulders. D, Plastic sheet over the buttocks. E, Plate for electrocautery. F, Burette for intravenous infusion.
Rupture of the sac is frequently secondary to increased pressure within the meningocele due to progressing hydrocephalus. Under these circumstances it is sometimes of value to use ventricular drainage for a time to reduce the cerebrospinal fluid pressure while the meningocele is healing. 7 It must be remembered, however, that such treatment may lead to prolonged hospitalization because the child may not tolerate being taken off drainage without first having some form of shunt procedure. This, as has been mentioned above, may be difficult to do :mccessfully.
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Franc D. Ingraham, Fred D. Fowler OPERATIVE TREATMENT
Surgical treatment should usually be delayed until the child is at least 12 to 18 months old. Operation is indicated for facilitation of care at home, and to help with orthopedic management. Rupture of the sac may necessitate operation if the leakage cannot otherwise be controlled. Recurrent meningitis due to skin organisms may indicate that the source of infection is through the sac wall and suggest the need for early removal. Once the decision has been made, the operation usually presents no serious difficulties. Endotracheal ether anesthesia is usually employed. A polyethylene tube is inserted into a peripheral vein for intravenous infusion during the operation. The child is placed in the prone position and rolls are put under the shoulders and hips in order that the chest and abdomen remain free and respirations are not hindered (Fig. 512). The table is adjusted so that the patient's head is slightly lower than his buttocks. This helps prevent excessive loss of cdrebrospinal fluid during the operation. After preparing the back a sterile plastic drape is placed below the lower end of the opeartive field to wall off the buttocks and anus. The back should be draped widely so that adequate skin may be mobilized for the closure if necessary. In the smaller lesions an elliptical skin incision may be made about the base down to the deep fascia and dissection carried around the neck of the dural sac (Fig. 513). The dura is then opened over what appears to be a thin area without underlying nervous tissue. This incision should be made as far away from the spinal canal as possible in order that there may be enough dura left to permit closure. The cutaneous portion of the sac is then inverted and any nerve elements which may be adherent in the inner wall are carefully dissected away. Some of the nerves may loop into the meningocele and return to the spinal canal and thence to the extremities. A nerve stimulator may be used to give some indication of which of these nerves may be intact, but if the child has any function below the level of the lesion it is better to preserve carefully all the nervous tissue that is present. Great care must be used to prevent contamination of the subarachnoid space with blood as this may lead to meningeal irritation and potentiate the development of postoperative hydrocephalus. It is not necessary to save the sac or to imbricate it because any possible resorptive capacity of the lining seems to have little if any effect on the occurrence of hydrocephalus. It is, however, possible to precipitate hydrocephalus by the sudden loss of large amounts of cerebrospinal fluid when the dura is opened. This causes acute coning of the cerebellar tissue in the ArnoldChiari malformation and subsequent interference with the established balance of cerebrospinal fluid circulation. The dura should be closed if at all possible. This closure is done with interrupted sutures and an attempt made to prevent any leakage of
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Fig. 513. Operative technique for myelomeningocele. A, Incision outlined (for large lesions the incisions are extended up and down at the lateral extent and the shaded area is undermined). B, The dissection is carried around the base of the lesion exposing the dura inside the spinal canal. C, The dura exposed and the sac held up with Allis forceps. D, The dura is incised showing the end of the spinal cord and nerve elements within. E, The sac is inverted over the operator's finger and the nervous tissue dissected away with a scalpel. F, The cord and nerve roots are replaced within the spinal canal and the dura sutured together. G, A lateral fascial flap may be brought over from either one or both sides to cover the spinal defect. H, Skin flaps may be rotated to get a primary suture without tension if there is a large defect in the skin.
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Franc D. Ingraham, Fred D. Fowler
cerebrospinal fluid through the suture line. This may be checked by having the anesthetist exert gentle pressure on the anterior fontanelle or on the jugular veins while the suture line is under direct observation. If there is functioning nervous tissue remaining in the spinal canal and dural closure would cause undue compression, it is better to leave the dura open and to swing lateral fascial flaps to cover the spinal canal. This gives some protection to the nerve elements and also helps to seal off the subarachnoid space. Nonabsorbable suture material such as silk or stainless steel wire is used throughout the closure. The lesions with a relatively small base can as a rule be closed quite easily. Those which are larger, however, have to be closed by turning flaps from above and below (Fig. 513, H), or by using relaxing incisions. Whatever method is used, it is essential that there be no tension on the suture line in the midportion ofthe wound overlying the spinal defect. Good skin approximation is also important because primary wound healing is a major factor in decreasing the length of hospitalization. In the treatment of lipomyelomeningoceles there are certain special considerations. It is important not to be too radical in removing such lesions. The fat, which is usually a large mass surrounding the nerve elements, may extend directly into the spinal cord itself and must be removed cautiously. Operation for this type of lesion is frequently for cosmetic reasons as the skin covering is usually good. It must be remembered that the 0peration will not in most instances improve nerve function even though the lipomatous portion may extend into the spinal canal and widen it. This fatty tissue is not actively expanding, but is present merely as a congenital remnant. Therefore only tissue which is easily removable should be excised. In the region of the causa equina where nerves are intermingled with tough fibrous strands and lipomatous tissue it is best to leave all deeper structures strictly alone as it is very easy to harm the child by attempting a complete removal. On occasion it is proper to operate on a child in the presence of an early progressive hydrocephalus if the mental function is still good and the local neural involvement is not marked. These children usually have some degree of involvement of the bladder sphincter and are subject to urinary tract infection and thus the ureteral shunt procedure cannot be safely used. If the child can be shown to have a communicating type of hydrocephalus preoperatively it is possible, however, to put in a sub- . arachnoid-peritoneal shunt at the time of removal of the meningocele. A small laminectomy is made just above the spina bifida. The dura is incised and a small hole made in the araehnoid membrane through which a No. 18 polyethylene tube is passed upwards into the thoracic subarachnoid space for a distance of 3 or 4 cm. A lateral incision is then made in the flank (or it is sometimes possible to expose the abdominal
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muscles through the back incision if large skin flaps are being turned) and the mUlilcles split in the direction of their fibers until the peritoneum is exposed. The tube is then passed subcutaneously or through the muscle between the two incisions and then inserted through a small opening into the peritoneal cavity. POSTOPERATIVE CARE
Except for those children with a very small and easily closed incision, the patient is positioned on a Bradford frame postoperatively (Fig. 514). The frame is covered with plastic sheeting and tilted so that the child's head is slightly lower than the buttocks, thereby reducing the cerebrospinal fluid pressure at the site of the dural closure. The patient's legs are
Fig. 514. Postoperative care on the Bradford frame.
restrained in the extended position to prevent flexion at the hip and possible distraction of the wound edges. No diapers are used and a hole is left in the center of the frame under which a bedpan may be placed. A plastic drape is stuck to the skin of the buttock just below the dressing and is brought over the dressing to act as a water-proof shield to protect the wound from contamination. Blankets may be put over a supporting frame to keep the child warm. These should not lie on the buttocks or wound, however. If the meningocele is large and there has been much loss of cerebrospinal fluid during the procedure, or if the child has any evidence of hydrocephalus, ventricular drainage should be instituted shortly after the operation. There may be sudden increase in intracranial pressure postoperatively if this is not done. The drainage tube is usually placed
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Franc D. Ingraham, Fred D. Fowler
at a height of 100 mm. and, starting on the second or third day, it is gradually raised over a three day period to a height of 250 mm. At this time, if there is no obstruction to the cerebrospinal fluid circulation, the amount of fluid drained off will be less than 50 cc. a day. The tube may then be clamped off for 24 hours and if this iR well tolerated by the child it can be removed. If the drainage does not decrease it may indicate that the cerebrospinal fluid pathways are obstructed. In spite of this the fluid circulation may eventually come into equilibrium and therefore it is usually wise to wait up to two or three weeks (changing the site of the drainage tube after ten days) in an attempt to avert the necessity for a shunting procedure. If in spite of these measures the child continues to run an elevated pressure, a posterior fossa decompression or a peritoneal shunt from either the ventricle or the lumbar region will have to be considered. The children are maintained on streptomycin for four days and penicillin throughout the postoperative period. It is necessary to inspect the wound on the day after operation to see whether any fluid has collected. This is prone to occur when the dura has not been closed or if extensive skin flaps have been mobilized. It is essential if fluid has accumulated that this be aspirated as often as necessary to keep the wound flat because the increased pressure caused by its presence may be sufficient to produce necrosis of the skin edges at the center of the incision. Sutures are left in for eight to 14 days to insure firm wound healing. Following removal of the sutures the patient may be taken off of the Bradford frame. Although the care of these patients may involve the management of many problems, the final results in properly selected and treated cases can be most gratifying. It has been estimated that about 30 per cent of these patients may be effectively rehabilitated. With the techniques now available for paraplegic training it is therefore possible for even a badly crippled child to lead a comfortable and useful existence. It is the responsibility of the attending physician to decide with care which of these children are satisfactory candidates for surgical therapy. Once this has been done the patient must be seen at intervals thereafter and his general pbysical condition evaluated if optimal results are to be obtained. SUMMARY
The conservative management of lumbar myelomeningoceles is emphasized. The care of these lesions has been outlined with suggestions regarding the selection of patients for operation as well as techniques for operative management. Consideration has been given to the occurrence of hydrocephalus and other complicating factors in these patients and their treatment has been discussed.
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REFERENCES 1. Patten, B. M.: Embryologic Stages in the Establishing of Myelochisis with Spina Bifida. Am. J. Anat. 93: 365-395, 1953. 2. MacMahon, B., Pugh, T. F. and Ingalls, T. H.: Anencephalus, Spina Bifida, and Hydrocephalus Incidence Related to Sex, Race, Season of Birth, and Incidence in Siblings. Brit. J. Prevo & Social Med. 7: 211-219, 1953. 3. Ingraham et al.: Spina Bifida and Cranium Bifida. Cambridge, Harvard University Printing Office, 1943. 4. Russell, D. S.: Observations on the Pathology of Hydrocephalus (M.R.C. Report No. 265). London, His Majesty's Stationary Office, 1949. 5. Gross, R. E., Holcomb, G. W. Jr. and Swan, H.: Treatment of Neurogenic Urinary and Fecal Incontinence in Children. Arch. Surg. 66: 143-154, 1953. 6. Campbell, J. B.: Congenital Anomalies of the Neural Axis. Am. J. Surgery 75: 231-256, 1948. 7. Bering, E. A. Jr.: A Simplified Apparatus for Constant Ventricular Drainage. J. Neurosurg. 8: 450-452, 1951.
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