All children born with a myelomeningocele have a. Tethered cord release: a long-term study in 114 patients. Clinical article

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1 J Neurosurg Pediatrics 3: , 3: , 2009 Tethered cord release: a long-term study in 114 patients Clinical article Ro b i n M. Bo w m a n, M.D., 1 Av i n a s h Mo h a n, M.D., 1 Jo y It o, R.N., 1 Ja s o n M. Se i b ly, D.O., 2 a n d Dav i d G. McLo n e, M.D., Ph.D. 1 1 Division of Pediatric Neurosurgery, Children s Memorial Hospital, Chicago; and 2 Department of Neurosurgery, BroMenn Regional Medical Center, Normal, Illinois Object. All children born with a myelomeningocele at the authors institution undergo aggressive treatment to maintain or improve functional outcome. Consequently, when any neurological, orthopedic, and/or urological changes are noted, a search for the cause is initiated. The most common cause of decline in a child born with a myelomeningocele is shunt malfunction. The second most common cause is tethering of the distal spinal cord at the site of the original back closure. In this report, the authors review the indicators of symptomatic spinal cord tethering and discuss the surgical interventions and outcomes in the children with myelomeningocele who underwent treatment at Children s Memorial Hospital from 1975 to Methods. Among the 502 children who underwent original closure at Children s Memorial Hospital, a symptomatic tethered spinal cord developed in 114 (23%). Eighty-one patients (71%) have undergone 1 untethering procedure, and 33 patients (29%) have undergone multiple untetherings, for a total of 163 total surgeries. The indicators of symptomatic spinal cord tethering include scoliosis, decline in lower-extremity (LE) motor strength, LE contractures, LE spasticity, gait change, urinary changes, and pain. Results. Pain has shown the best response to surgical untethering, with 100% of children experiencing postoperative improvement. The results of long-term follow-up (average 12 years, range 1 month 23.3 years) in this cohort demonstrated scoliosis progression after surgical untethering in 52% of patients, with 28% requiring spinal fusion. On the 3-month postoperative manual muscle test, 70% of patients showed improved LE muscle strength compared to preoperatively. Gait was also similarly improved after untethering as evaluated by an orthopedic surgeon. Spasticity improved in two-thirds of the cohort, and as expected, LE contractures were stable (78%) postoperatively, as assessed by orthopedic and rehabilitation medicine specialists. Urologically, 64% of patients showed improvements on postoperative bladder evaluation. Conclusions. Although this is a clinical outcome study with no control group, the authors experience has been that tethered cord release is beneficial in maintaining neurological, urological, and orthopedic functioning in children born with a myelomeningocele. (DOI: / PEDS0874) Ke y Wo r d s myelomeningocele scoliosis spinal cord tethering Abbreviations used in this paper: CMH = Children s Memorial Hospital; LE = lower extremity; MMT = manual muscle test; TCR = tethered cord release. All children born with a myelomeningocele have a low-lying cord on MR imaging, even after initial repair and untethering, consistent with tethering, or scarring, in the area of the prior exposed neural placode. Fortunately, only approximately one-third or fewer of these children will show signs of neurological, orthopedic or urological decline related to spinal cord tethering, despite the probability of being anatomically tethered. 4 All children born with myelomeningoceles at CMH are closely monitored throughout childhood by our multidisciplinary spina bifida clinic. Our team consists of practitioners of neurosurgery, orthopedic surgery, urology, neurology, physical/occupational therapy, physical medicine and rehabilitation, nursing, and social work. Although children born with a myelomeningocele usually have neurological, orthopedic, and/or urological deficits, it is our goal that the children remain functionally stable or improve throughout childhood. This requires diligence both from the medical team and the child s family. The children are evaluated in our clinic by the entire spina bifida team every 3 months during the 1st year of life and then every 6 months until school age. Subsequently, the children undergo examinations on at least a yearly basis by the entire multidisciplinary team. The family is instructed 181

2 R. M. Bowman et al. to contact us should they note neurological, orthopedic, or urological changes in their child between office visits. We have found, as have others, that the most common cause of neurological changes in a child with a myelomeningocele is shunt malfunction. 6 The second most common cause of clinical decline is symptomatic tethering of the spinal cord at the site of the placode closure as an infant. 4 This report is an outcome study in children who underwent original back closure at CMH and subsequently required a TCR. We will analyze the clinical presentation and subsequent neurological, urological, and orthopedic outcomes, as well as the surgical procedure and complications. A majority of these surgical procedures were performed by the senior author (D.G.M.), and all were undertaken at CMH. Methods The multidisciplinary spina bifida clinic at CMH was originally established in Since then we have aggressively managed the care of all children born with a myelomeningocele in a prospective manner with the goal of maintaining or improving long-term functional outcome. These results are a compilation of these data. Since 1975, 502 newborns with myelomeningocele, have undergone back closure at CMH. In this cohort, 114 children (23%) underwent TCR at CMH. Eighty-one patients (71%) had only 1 untethering, 20 patients (17%) underwent 2, 10 patients (9%) had 3 untetherings, and 3 patients (3%) had 4 untetherings. Overall there were 163 TCR procedures in 114 patients. All newborns undergo an initial baseline LE MMT performed by the physical therapist following birth, before myelomeningocele closure. The children then undergo a 3-month postclosure MMT and at least yearly studies henceforth. If a concern is raised about possible declining LE strength in a child, MMT is repeated at that time and 3 months after any intervention. Following the birth of a child with open spina bifida, baseline evaluations are completed by specialists in neurosurgery, orthopedic surgery, and urology. The child subsequently receives follow-up with intermittent team examinations that may include MMT, renal ultrasonography, cystometrography, voiding cystoureterography, brain and spine MR imaging or CT scanning, plain radiography, and/ or gait studies. A child s myelomeningocele level is determined by his/her LE functional ability as displayed on the MMT. As determined by a physical therapist on the baseline MMT, a majority of patients had symmetrical innervations of their lower extremities, although, in some patients, one LE may exhibit greater strength then the other. In this group of 114 patients, only 1 patient (1%) had an asymmetrical motor examination, with 1 LE having motor power into the lower lumbar roots and the other limb flaccid. In the remaining children, 14 patients (12%) had an upper lumbar or thoracic motor level, 6 patients (5%) had an L-3 motor level, 25 patients (22%) had an L-4 motor level, 33 patients (29%) had an L-5 motor level, and 35 patients (31%) had a sacral motor level. Our cohort consisted of 58 female and 56 male patients. TABLE 1: Age distribution for each TCR Age (yrs) 1st TCR (114 total) 2nd TCR (33 total) No. of Children 3rd TCR (13 total) 4th TCR (3 total) < > In this group, 108 patients (95%) had shunted hydrocephalus. The mean age at the time of the first untethering was 7 years (range 7 months 21.8 years). Table 1 displays the age distribution at the time of each TCR. The youngest child in this cohort underwent an untethering with resection of his recurrent teratoma when he was 7 months of age. The mean length of follow-up after the initial untethering was 12 years, with a range of 1 month to 23.3 years. The mean length of follow-up after the second release was 4.6 years (range years), 3.4 years after the third (range years), and 3.3 years after the fourth ( years). The clinical signs or symptoms our spina bifida team uses as indicators of spinal cord tethering include progressive scoliosis, decline in LE motor strength, LE contractures, LE spasticity, gait changes, change in urological function, and/or back pain (Figs. 1 and 2). One child underwent TCR with resection of a recurrent teratoma at the site of the neural placode. A second child underwent both a posterior cervical decompression and TCR simultaneously for progressive upper-extremity weakness. When functional decline is suspected, the patient undergoes at least an MMT, cystometrography, and brain/ spine MR imaging with an evaluation by the full team, including specialists in neurosurgery, orthopedics, and urology. We rely on our colleagues in urology and orthopedics to determine whether the noted change is expected for the child given his/her baseline function, or if the change is an unexpected decline in function. All decisions to offer an Fig. 1. Bar graph of clinical indicators of tethering in 114 patients. 182

3 Tethered cord release: a long-term study in 114 patients Fig. 2. Bar graph of clinical indicators of tethering in 163 procedures. untethering procedure to the child who has demonstrated an unexpected functional decline are made by the multidisciplinary spina bifida team. Proper shunt function is always confirmed before a diagnosis of symptomatic tethered spinal cord is made. The child undergoes a clinical examination and images of the brain are obtained. If concerns arise regarding possible shunt malfunction, the shunt is either tapped and/or surgically explored prior to any untethering procedure. Fig. 3. Sagittal T1-weighted lumbar MR image demonstrating tethering in the area of the previously exposed neural placode. Surgical Intervention After adequate shunt function is confirmed, the child is positioned prone on chest gel rolls to avoid pressure sores. Prior to positioning, a urinary catheter is placed. A prophylactic antibiotic is administered. Preoperative MR images assist in determining the location and extent of the surgical incision (Fig. 3). Most of the time, the entire previous myelomeningocele scar will need to be reopened. If the child originally underwent closure with a transverse incision, we create a longitudinal incision dorsal to the placode. The incision is started superiorly, dorsal to the last intact lamina, and carried deep to the fascial layer. The paraspinal musculature is dissected laterally, exposing the last intact lamina. The ligamentum flavum is released from the undersurface of the intact lamina utilizing periosteal elevators, thereby exposing the superior epidural plane. If adequate normal dura mater is not present, then a small inferior laminectomy is completed with bone rongeurs. If there is significant fibrofatty tissue in the epidural plane, the CO 2 laser is useful in identifying the dura distally. Prior to dural opening, the child is tipped gently into the Trendelenburg position to limit the amount of spinal fluid loss. The dura is subsequently opened superiorly and retracted laterally. At the time of the original closure, the placode is imbricated, and hence, the tether is usually along the dorsal, pial suture line. During the dissection, we continually work distally on either side of the cord, taking care to preserve all dorsal nerve roots. All intradural dissection is completed with operating loupes and a headlight. If the spinal cord is densely adherent to the dorsal dura, dissection is carried out laterally on either side of the adherent zone, eventually circumferentially untethering the cord, except for the dorsally adherent dura. At this point, usually by working gently in all directions, the small, adherent dorsal dura is able to be removed. At the conclusion of the untethering, the spinal cord relaxes into the anterior spinal canal. Our senior author (D.G.M.) has noted no difference in outcome when intraoperative neurophysiological monitoring is used. Consequently, these surgical procedures are completed without the use of monitoring, but with diligent preservation of all nervous tissue during the release, even if the spinal cord cannot be untethered completely. Once the spinal cord is completely untethered, the spinal column should be inspected for other pathological entities including dermoid tumors in the distal spinal cord, a fatty or thickened filum, or split cord malformation. If other pathologies are confirmed, they are resected or released. After confirming that no other lesion is present, the dura is closed in a watertight fashion. Synthetic and cadaveric dural substitutes were used in 9 patients 183

4 R. M. Bowman et al. (AlloDerm in 4; cadaver dural graft in 4; GoreTex in 1) to create a capacious, watertight dural closure. The deep layers are closed and the skin is secured with nonabsorbable suture. Postoperatively, the child is maintained on flat bed rest for 4 days and then slowly mobilized. Results In this cohort of 114 patients, there were 163 TCR procedures. All children underwent full evaluations with postoperative MMTs and cystometrography 3 months after untethering and subsequently attended follow-up on a yearly basis. The results of these data were compiled for each procedure and analyzed for this report (Table 2). Management of Scoliosis Forty-six patients (40%) underwent untethering secondary to progressive scoliosis, and 13 (11%) had only this symptom. Sixty-seven TCRs (41%) were performed for progressive scoliosis. These data were analyzed using 5 of change in the spinal curvature as significant for improvement or progression. Ten children (22%) with severe scoliosis (curve range ) underwent untethering immediately prior to spinal fusion to prevent neurological decline secondary to possible spinal column lengthening. Of the remaining 36 patients, 8 (17%) showed improvement in their scoliosis (mean curve improvement 18, range 5 30) and 4 patients (curve range ) had stabilization of their spinal curvature. Eleven patients (24%) progressed postoperatively, but received conservative treatment with bracing and have not undergone spinal fusion. In these 11 patients, the range of the spinal curvature is (mean 58). The mean progression of the curvature is 26 (range 6 64). In 2 of these patients, spinal fusion was recommended by the orthopedic surgeons, but the family declined. Continual scoliosis progression that subsequently required spinal fusion was shown in 13 patients (28%). This subset of patients underwent clinical follow-up for a mean of 7.2 years after untethering surgery until spinal fusion (range years). The average age at the time of spinal fusion was 11.5 years (range ). Seven of these children function at a thoracic level. The mean curve at the time of spinal fusion was 69 (range ), with a mean progression of 34 (range 16 64). Of the 13 children in whom scoliosis was the only presenting symptom, 4 patients underwent an immediate spinal fusion. Five patients eventually required spinal fusion, and 4 either stabilized or showed improvement in their scoliosis. Decline in MMT Forty-seven children (41%) received diagnoses of symptomatic tethered cords after their LE strength declined. Fifty-four TCRs (33%) were performed in these 47 children. In 6 procedures (11%), a change in the MMT was the only indication of neurological worsening. In these 54 release surgeries, 70% resulted in improvement in motor functioning as assessed by physical therapists on the postoperative MMT, and in 28% the patients remained in stable condition. One surgery (2%) led to further decline in the child s LE motor strength postoperatively. Lower-Extremity Contractures Thirty-seven TCRs (23%) were performed in 34 patients (30%) due to the development of LE contractures. In 1 patient, the development of contractures was the only symptom of tethering. As expected, 22% of the contractures were improved postoperatively as assessed clinically by an orthopedic surgeon, with 78% remaining in stable condition. Lower-Extremity Spasticity Spasticity was the indicator of tethering that led to 75 TCR procedures (46%) completed in 54 patients (47%), and was the only indication in 11 cases. Evaluation by orthopedic and rehabilitation medicine specialists 3 months postoperatively in these patients revealed that spasticity was improved in 63% and remained stable in 37% of the cohort. Gait Changes A worsening in the child s gait was a clinical sign of symptomatic tethering in 29 patients (25%) who underwent 32 procedures (20%). Two release surgeries were performed in a patient with gait changes as the only indicator of tethered cord. At the 3-month postoperative visit, 79% of patients showed improvement in this symptom, and 19% remained stable, as determined by orthopedic TABLE 2: Summary of the outcome data for each clinical indicator for TCR in 114 patients* Clinical Indicator Preop Symptom Improved Stable Worsening/Progression Comment scoliosis 46 (40) 8 (17) 4 (9) 24 (52); 13 spinal fusions 10 untetherings w/ spinal fusion MMT changes 47 (41) 33 (70) 13 (28) 1 (2) 3 worse; no weakness preop contracture 34 (30) 7 (22) 27 (78) spasticity 54 (47) 34 (63) 20 (37) gait change 29 (25) 23 (78) 5 (17) 1 (3) back or leg pain 19 (17) 19 (100) urinary changes 30 (26) 20 (67) 9 (30) 1 in early postop period * Data include the entire duration of follow-up for all patients. 184

5 Tethered cord release: a long-term study in 114 patients surgery and rehabilitation medicine specialists. One child (3%), the same child who had a worsened MMT postoperatively, had a worse gait because of increased weakness in her quadriceps. Urinary Changes In 30 children (26%), worsened urological functioning was a clinical sign of tethering, as determined by our urologist based on cystometrography, voiding cystoureterography, and/or renal ultrasonography. Thirty-seven procedures (23%) were performed for deteriorating urological functioning, and in 10 cases this was the sole indication for intervention. One child is currently in the early postoperative period and therefore has not yet undergone postoperative studies. In the remaining 36 procedures, 64% resulted in improvement and 36% in stabilization of urological symptoms on the postoperative evaluation. Postoperatively, no child had worsened urologically. Interestingly, 9 children have undergone an untethering for reasons other than urologic decline, but have experienced an improvement in urologic functioning postoperatively. One child, however, has developed a decrease in his bladder capacity that has gradually improved back to baseline as shown on serial cystometrograms. Back Pain Nineteen patients (17%) complained of low-back pain preoperatively and underwent 24 untetherings (15%). Postoperatively, all patients experienced improvement in their pain. Back pain was the sole indicator for tethering in only 1 patient. Another patient with back pain received a diagnosis of anterior meningocele and pelvic dermoid. After closure of the meningocele and resection of the tumor, the pain resolved. At 1 year of age, 1 infant underwent untethering for back fullness and irritability (possibly due to back pain). The symptoms resolved postoperatively. Unique Indicators A teratoma at the site of the placode was diagnosed in 1 newborn. This tumor was resected at the time of the myelomeningocele closure. The infant underwent close follow-up for possible tumor recurrence with frequent MR imaging and alpha-fetoprotein level assays. At 7 months of age, he was noted to have a regrowth of the tumor and an increase in his alpha-fetoprotein level. He underwent untethering with subsequent gross-total resection of the tumor. At 2 years after surgery, he has had no further recurrence. He functions at a thoracic motor level and has had no neurological changes since birth. Upper-extremity weakness developed in 2 children. One child improved after a simultaneous TCR and posterior cervical decompression. The other patient is paraplegic and underwent transection of the lower thoracic spinal cord. Upper-extremity strength in this patient has improved postoperatively. Additional Pathological Entities Nineteen children (17%) had at least 1 other form of spinal disease, some of which are tethering in nature. In all 19, the additional lesions were diagnosed on either preoperative MR images or at the time of the untethering; none were noted at placode closure. Seven children (6%) had distal spinal cord dermoid lesions, and 7 patients (6%) had thickened, fatty fila. Four patients (4%) had diastematomyelia (split cord malformation) at the level of the placode. One child had a distal lipoma, and another child had an associated subcutaneous fibroma. One of the children with dermoid tumors had an associated anterior meningocele. Lastly, 1 newborn had a teratoma ventral to his placode. Complications Overall, only 4 children of the 114 (3.5%) were neurologically worse after untethering (Table 3). All 4 patients declined by at least 1 motor level on the MMT. In 3 patients, this weakness arose after the first untethering, and in another patient after the second surgery. In 2 patients, there was an associated lesion consisting of a large, distal dermoid tumor in 1 child, and a diastematomyelia with a thickened, fatty filum in another. Other complications have consisted of CSF leak after 7 releases (4%) and wound dehiscence/infection in 11 (7%). No patient who required a dural patch developed a postoperative CSF leak. Of the patients with a postoperative CSF leakage, 4 required temporary CSF diversions and another underwent ventriculoperitoneal shunt revision. One patient required a wound revision and another improved after an extended period of flat bed rest. In the 2 children with wound dehiscence, intravenous antibiotic agents were used with dressing changes; a sample in 1 patient cultured positive for meningitis. All cases of superficial wound dehiscence healed with local wound care (wet to dry dressing changes). Discussion As previously stated, we are strong advocates of aggressive treatment in children born with myelomeningoceles so that neurological decline can be prevented. The most common cause of neurological changes in these patients is a shunt malfunction. 6 Most patients will require 2 3 shunt revisions throughout childhood. 4 Shunt malfunctions can mimic the signs of a tethered cord; consequently shunt function must always be confirmed prior to any surgical untethering. Opening the central nervous system inferior to the tentorium in a child with a Chiari malformation Type II and an unrecognized shunt malfunction may have life-threatening consequences. 14 The second most common cause of decline in a child born with an open neural tube TABLE 3: Summary of complications in 163 procedures* No. of Patients Complication Comment 4 worsening (decline in motor strength) 2 associated pathological entities 7 CSF leak 4 temporary CSF diversion; 1 VP shunt revision 9 superficial wound dehiscence 2 wound infection 1 w/ meningitis * VP = ventriculoperitoneal. 185

6 R. M. Bowman et al. defect is tethering of the distal spinal cord. As reported by Phuong et al., 9 without surgical release of a symptomatic tethered cord, 60% of children will experience further orthopedic and urological decline within 5 years. Yamada and colleagues 15 have supplied the physiological data that support the concept of stretch-induced trauma to the distal spinal cord when it is held under tension. Consequently, it is not surprising that symptoms of a spinal cord held taut by scar are referable to the region of the lumbosacral spinal cord. In the present study, the most common presenting symptoms of spinal cord tethering were spasticity of the lower extremities (47% patients, 46% TCRs), decline in LE strength (41% patients, 33% TCRs), and scoliosis (40% patients, 41% TCRs). Approximately 25% of the cohort presented with either urinary changes or a worsening, crouched gait. The least common presentation was pain, which was present in 17% of the children. Outcome is best assessed by reviewing each individual presenting symptom, given that 73% of untethering procedures were performed secondary to > 1 clinical indicator of tethering (Table 2). Fortunately, of all the neurological problems exacerbated by a tethered spinal cord, pain shows the best response to untethering in children. In our cohort, 100% of patients had improvements in their pain postoperatively. Rinaldi et al. 11 and Cochrane and colleagues 5 also found that pain responds well to untethering in children with spinal dysraphism. The pain is usually vague and difficult for the child to localize and often radiates into the anterior thigh or even up the spine. Neck flexion can exacerbate the pain and lordotic posture with bent knees can reduce it. Gait and LE motor strength are significantly improved with release of a symptomatic tethered cord. Seventy-eight percent of children experience an improvement in their gait with 70% experiencing improvement in LE motor strength as tested by a physical therapist. These findings are in contrast to Schoenmakers et al., 13 who noted that symptoms in the majority of their patients (82%) remained stable postoperatively and only 7% showed improvement. Although only 1 paraplegic patient in that cohort underwent cord transection for upper extremity weakness, she experienced significant improvement in her hand strength postoperatively. Blount and colleagues 3 have reported similar findings in several patients. In a long-term outcome study from the Netherlands in children with different types of spinal dysraphism, 5 of 44 patients (11%) showed postoperative motor examination deterioration. 13 The overall risk of LE motor strength decline is 3.5%. One child had weaker quadriceps postoperatively that initially affected her gait. Although she had some gradual improvement in strength, her weight gain prevented ambulation. Three other children lost motor strength postoperatively, although weakness was not a presenting symptom. Two of these children had associated lesions, with 1 child harboring a very large, distal dermoid tumor. Very snug dural closure was performed in the last child in an attempt to close the dura in a watertight fashion. In the immediate postoperative period, this patient was noted to have increased weakness in his LEs. Reexploration with dural patching was promptly performed with some longterm improvement in his LE strength. As expected, a majority of children with contractures (78%) were in stable condition postoperatively and required subsequent orthopedic procedures. This finding was supported by the work of Archibeck et al., 2 who found a significant increase in orthopedic procedures per year after the initial untethering. These results mirror our clinical practice. We initially recommend an untethering prior to corrective orthopedic procedures in patients with contractures. A corrective orthopedic procedure without a release of the tethered cord will not prevent further orthopedic or urological decline. 9 In children with urological decline as an indicator of tethering in the present study, 64% of patients experienced improvement, and 36% remained stable on postoperative testing. Our results are in contrast to those of Abra hamsson et al., 1 who found that all 6 patients with deterioration prior to untethering had improved urodynamics postoperatively. In this study, we noted improvements in urodynamic testing and function in 9 children after untethering for reasons other than urological decline. Interestingly, the 1 child who had an initial decrease in bladder capacity but stable pressures on his 3-month postoperative cystometrogram also experienced a very impressive increase postoperatively in strength in all LE muscle groups. Perhaps the untethering of his spinal cord improved his oxidative metabolism, 15 thereby increasing the sacral reflex arch to his bladder. Fortunately, over the course of 15 months, his bladder capacity improved and returned to baseline status. Scoliosis was an indicator of tethering in this series of patients. In prior studies, untethering was felt to be beneficial for stabilization or improvement of the spinal curvature. 7,8,12 Indeed this has been shown to be true within the 1st year postoperatively. In our group s prior study in 30 children with scoliosis who underwent an untethering, 96% either had improvement or stabilization of their curvatures at the 1-year follow-up examination. 8 In the Sarwark et al. 12 study of children with an L-3 level and below, 75% were either stable or improved at 1-year postoperatively, but > 41% were noted to have progression at long-term follow-up (range of 3 7 years). In this cohort, all patients with stable or improved spinal curvatures after TCR had a scoliosis curvature of 46 preoperatively. In 2 separate studies by McLone s team, 7,8 scoliosis was found to have progressed in ~ 38% of the cohort at longterm follow-up (2 7 years). The unique difference between the present study and the other reports is the extended length of follow-up (average 12 years, range 1 month 23.3 years). The results of the present study are comparable to the findings of Pierz et al. 10 who noted progression in 57% of patients, 48% undergoing spinal fusion, at a 5-year follow-up period. In this long-term study, 52% of the cohort have progressive scoliosis after untethering. Twenty-three patients (50%) underwent spinal fusion, with 10 children undergoing fusion at the time of untethering. Twenty-six percent of the cohort (12 patients) have improved or stabilized. In the 11 children with progression of the spinal curvature, but no fusion, 9 children are at skeletal maturity and will most likely never require a fusion. Further extensive evaluation of this cohort is needed to determine whether early untethering is beneficial in 186

7 Tethered cord release: a long-term study in 114 patients stabilizing a child s spinal curvature long enough to allow for skeletal maturity. Untethering of the distal spinal cord, however, does not appear to prevent the need for eventual spinal fusion in a majority of children born with an open neural tube defect. Conclusions Symptomatic tethering of the closed neural placode occurred in ~ 23% of the children who underwent treatment at CMH since In this prospectively managed cohort, release of the tethered spinal cord was beneficial in a majority of patients in maintaining or improving their neurological, orthopedic, and urological disabilities at relatively low risk of complications (3.5%). Disclaimer The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Acknowledgments The authors would like to express their sincere appreciation to Ms. Sana Abbed and Ms. Vanda Boshnjaku, their administrative assistants. References 1. Abrahamsson K, Olsson I, Sillen U: Urodynamic findings in children with myelomeningocele after untethering of the spinal cord. J Urol 177: , Archibeck MJ, Smith JT, Carroll KL, Davitt JS, Stevens PM: Surgical release of tethered spinal cord: survivorship analysis and orthopedic outcome. J Pediatr Orthop 17: , Blount JP, Tubbs RS, Okor M, Tyler-Kabara EC, Wellons JC III, Grabb PA, et al: Supra-placode spinal cord transection in paraplegic patients with myelodysplasia and repetitive symptomatic tethered spinal cord. J Neurosurg 103 (1 Suppl):36 39, Bowman RM, McLone DG, Grant JA, Tomita T, Ito JA: Spina bifida outcome: a 25-year prospective. Pediatr Neurosurg 34: , Cochrane DD, Rassekh SR, Thiessen PN: Functional deterioration following placode untethering in myelomeningocele. Pediatr Neurosurg 28:57 62, Dias MS, McLone DG: Hydrocephalus in the child with dysraphism. Neurosurg Clin N Am 4: , Herman JM, McLone DG, Storrs BB, Dauser RC: Analysis of 153 patients with myelomeningocele or spinal lipoma reoperated upon for a tethered spinal cord. Pediatr Neurosurg 19: , McLone DG, Herman JM, Gabrieli AP, Dias L: Tethered cord as a cause of scoliosis in children with a myelomeningocele. Pediatr Neurosurg 16:8 13, Phuong LK, Schoeberl KA, Raffel C: Natural history of tethered cord in patients with meningomyelocele. Neurosurgery 50: , Pierz K, Banta J, Thomson J, Gahm N, Hartford J: The effect of tethered cord release on scoliosis in myelomeningocele. J Pediatr Orthop 20: , Rinaldi F, Cioffi FA, Columbano L, Krasagakis G, Bernini FP: Tethered cord syndrome. J Neurosurg Sci 49: , Sarwark JF, Weber DT, Gabrieli AP, McLone DG, Dias L: Tethered cord syndrome in low motor level children with myelomeningocele. Pediatr Neurosurg 25: , Schoenmakers MA, Gooskens RH, Gulmans VA, Hanlo PW, Vandertop WP, Uiterwaal CS, et al: Long-term outcome of neurosurgical untethering on neurosegmental motor and ambulation levels. Dev Med Child Neurol 45: , Tomita T, McLone DG: Acute respiratory arrest. Am J Dis Child 137: , Yamada S, Won DJ, Yamada SM: Pathophysiology of tethered cord syndrome: correlation with symptomatology. Neurosurg Focus 16(2):E6, 2004 Manuscript submitted April 22, Accepted December 1, Address correspondence to: Robin M. Bowman, M.D., 2300 Children s Plaza, Box 28, Chicago, Illinois