Childs Nerv Syst DOI 10.1007/s00381-015-2748-9

ORIGINAL PAPER

Tethered cord syndrome in children: a single-center experience with 162 patients Murat Geyik 1 & Mehmet Alptekin 1 & Ibrahim Erkutlu 1 & Sırma Geyik 2 & Cem Erbas 3 & Serhat Pusat 4 & Cahit Kural 5

Received: 25 April 2015 / Accepted: 8 May 2015 # Springer-Verlag Berlin Heidelberg 2015

Abstract Purpose Tethered cord syndrome (TCS) is not an uncommon clinical problem in children. The aim of this retrospective study is to document our experience on the surgical treatment of TCS in childhood. Methods The data of 162 children who underwent surgical treatment for TCS in a 15-year period were reviewed retrospectively. Their demographic, clinical, radiological, and surgical features were documented. They were divided into two groups as primary and secondary TCS, and the surgical technique for each group was demonstrated. Untethering the spinal cord and correction of the associated malformation were the standard surgical technique for each patient. The results of the treatment were summarized. Results Among the 162 children, 101 (62.3 %) of them were female and 61 were male with a mean age of 62 months. Primary TCS was detected in 43 patients while secondary TCS was found in 119 (73.4 %) patients. Hypertrichosis was the most common physical finding while back pain was the common complaint. Lipoma, split cord malformation, dermal sinus tract, and myelomeningocele were the associated malformations for secondary TCS. * Murat Geyik [email protected] 1

Department of Neurosurgery, Gaziantep University, Gaziantep, Turkey

2

Department of Neurology, Gaziantep University, Gaziantep, Turkey

3

Department of Neurosurgery, Bilgi Hospital, Ankara, Turkey

4

Department of Neurosurgery, Etimesgut Military Hospital, Ankara, Turkey

5

Department of Neurosurgery, Gulhane Military Medical Academy, Ankara, Turkey

Conclusions Children should be individualized for the treatment of TCS. Each patient must be evaluated neurologically and radiologically for the accurate diagnosis. Surgical untethering is the safe and effective method of treatment for children with TCS. Keywords Tethered cord syndrome . Children . Surgery

Introduction Tethered spinal cord syndrome (TCS) is a neurological disorder due to the limitation of the movements of spinal cord by the attachments within the spinal canal [6, 14, 26, 29]. It is an important neurological and urological problem in children [7, 20, 26]. TCS may be an isolated anomaly (primary TCS) or secondary to other associated lesions such as split cord malformation (SCM), lipoma, dermal sinus tract, myelomeningocele, and meningocele [1, 9, 17, 25]. The pathophysiology of TCS is not well known. The spinal column develops faster than the spinal cord during fetal development, and abnormal attachments lead to stretching of the spinal cord [28, 30]. In the meantime, impaired oxidative metabolism in the affected spinal cord plays an important role on the development of SCM [30].Tethering may also develop after spinal cord injury, and the scar tissue can block the flow of cerebrospinal fluids (CSFs) around the spinal cord [21, 22, 27]. Secondary TCS is closely associated with spina bifida, and its presentation in childhood may be with the cutaneous findings of spinal dysraphism (hypertrichosis, port-wine stain, dimple, hemangioma, subcutaneous lipoma) [11, 12, 15, 16, 19]. It may be associated with foot deformities, leg numbness and weakness, low back pain, scoliosis, and urinary or anal incontinence [13, 24, 31].

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Treatment of TCS is mainly surgical. Untethering the spinal cord is essential for an effective improvement in TCS [26]. Associated malformations and lesions should also be treated in the same session. Cutting the filum terminale (FT), even if it has a normal appearance, is crucial for a satisfactory untethering procedure [16]. The aim of this report is to present our series of TCS in children and to document clinical, radiological, and surgical characteristics of this syndrome. The findings of our series will also be discussed with the current literature. Fig. 2 Intraoperative view of the split cord malformation in a child with TCS. The bony septum divided the dura mater into the two hemicords

Patients and methods A total of 179 patients underwent surgical treatment for TCS in our department between 2000 and 2014, and 162 (90.5 %) of them were children. The data of these 162 children were evaluated retrospectively. All of them had either primary or secondary TCS. They were evaluated clinically and radiologically before the operations. Computed tomography (CT) and magnetic resonance imaging (MRI) were the radiological techniques that were used in preoperative evaluation of the children (Fig. 1). They operated for primary and secondary TCS (lipoma, split cord malformation, dermal sinus, and myelomeningocele) in a 15-year period. Release of the spinal cord and correction of the associated malformation were performed in all patients (Figs. 2 and 3). FT was cut in all patients

Fig. 1 The T2 sagittal MRI of the patient showing the tethering of the spinal cord at cervical spine associated with the syringomyelia

during the surgery (Fig. 4). Intraoperative neurophysiological monitoring was performed in all patients. The mean follow-up period was 47 months, ranged between 2and 120 months. All patients were examined neurologically in the follow-up period, and MRI was performed in patients having suspect of retethering.

Results One hundred and one (62.3 %) of them were female and 61 were male with a mean age of 62 months, ranged between 2 monhts and 17 years. Primary TCS was detected in 43 patients while secondary TCS was found in 119 (73.4 %) patients. Among the patients with secondary TCS syndrome, lipoma was associated with lesion in 23 patients while SCM in 51 patients, dermal sinus tract in 18 patients, and previous operation for myelomeningocele and meningocele in 27 patients. Back pain was present in 86 patients in the preoperative period. Preoperative clinical findings were hypertrichosis (Fig. 5) in 57 patients, leg weakness in 29 patients, and urinary problems in 26 patients. Physical examination was normal in 97 patients. Back pain was improved in 53 (61.6 %) patients after surgery. Neurological improvement was observed in 5

Fig. 3 Intraoperative view of a terminal lipoma attached to the spinal cord. The attachments of the lipoma to the adjacent dura are obvious. These attachments should be cut in order to relase the spinal cord. Black arrows show the attachments. DMdura mater

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Fig. 4 Identification of the filum terminale during the surgery for TCS. There are many fibrous bands between the fatty FT and sacral rootlets. Black arrows show the attachments. FTfilum terminale, Rrootlets

(17.2 %) patients while urological improvement was observed in 3 (11.5 %) patients. CSF collection was observed as a postoperative complication in 3 patients. There was no death secondary to surgical traetment.

Discussion The surgical outcome of 162 pediatric patients with TCS is reported. Most of them were female patients. Secondary TCS was found in 73.4 % of the patients. SCM was the most common associated malformations in children with secondary TCS, and hypertrichosis was the most common physical finding. Neurological improvement was present in 17.2 % of the patients while urological improvement was observed in 11.5 % of the patients. TCS is a stretch-induced functional disorder of the spinal cord due to excessive tension that develops usually between the spinal cord and dura mater. The cord is abnormally fixed to a caudal structure of the spine (dermal sinus, scar tissue, fibrous bands) that limits motion of the cord in the caudalrostral direction [10]. Low elasticity secondary to the destruction of the three-dimensional structure of FT is important in the development of TCS [17, 18, 27].

Fig. 5 A child with hypertrichosis at the lumbar region. Type I SCM was detected in this child and operated for TCS

Secondary TCS is more common than the primary TCS. The associated conditions to secondary TCS are as follows: tight and fatty FT, lipomyelomeningocele, SCMs, dermal sinus tracts, dermoids, previous myelomeningocele and meningocele, and cystoceles [2, 3, 4]. SCMs may be type 1, type 2, or composite type [3, 13]. Dermal sinus tracts may attach to the FT or conus medullaris and cause TCS [15, 19]. Inappropriate surgical interventions for midline fusion defects are the important causes of TCS in children [22]. In general, all of these conditions pull the spinal cord at the base of the spinal canal. As children grow, their spinal cords do not grow as fast as the spinal column. So, the spinal cord must be able to freely ascend on the inside of the spinal column during growth. If various abnormal structures are holding onto the spinal cord from below, it stretches the spinal cord resulting in progressive loss of neurological functions. In our series, secondary TCS (73.4 %) is the most common form of TCS and SCM is the most common associated malformation to the TCS. We also observed dermal sinus tracts and lipomas as a stretching lesions of the spinal cord. TCS is a benign clinical condition. But it can cause terrible neurological and urological consequences if not treated in children with spina bifida. Pain is the most common complaint in children. They may show some signs of discomfort due to back pain in younger age [26]. As tethering progress, they fail to gain or lose functions of the feet, legs, bowel, or bladder. Urinary and/or anal incontinence may occur [8, 31]. Luckily, most of the conditions are picked up early due to unusual cutaneous signs in the midline of their backs. These include fatty masses (subcutaneous lipoma), areas of increased pigmentation (port-wine stain), dimples (dermal sinus tract), or large collections of hair (hypertrichosis). When noticed, these skin signs should prompt a radiological examination which usually includes an MRI or CT scan [11]. During the infancy, an ultrasound may be helpful to identify one of these clinical conditions. Not to confuse things, it should be understood that if there is a problem in one region of the spinal cord, then there may be other problems in the other parts of the spine. For example, before the cutting of FT, the whole spine should be screened in order to detect any other splitting lesions the spinal cord. For this reason, it is necessary to investigate the entire spinal cord and potentially the cranium prior to treatment of the malformation. In our series, we examined radiologically the whole spine and the cranium before the treatment of TCS. Radiological examination is important in children with suspected TCS. Low-lying conus medullaris (below L2) and thick filum terminale (>2 mm) are the classic radiological features of TCS [6, 17, 26, 27]. Ultrasound may be useful for screening the TCS and may be used in the newborn population [26]. The lack of ossification of the posterior arch of the spine in normal infants and the presence of a bony defect in patients with spina bifida permit ultrasonographic examination for the detection of TCS. CT may be used for the

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determination of fusion defect and SCM in children. MRI is helpful in visualizing the conus medullaris, assessing the thickness of the FT, identifying traction lesions, and evaluating associated bony dysraphisms. Prone imaging may be useful in patients who have undergone TCS surgery or in those in whom clinical suspicion is high while supine MRI demonstrates no abnormalities. Prone MRI imaging is however of little value when supine MRI has demonstrated the defect. We used CT for the evaluation of bony structure of the spinal column and MRI for the determination of the level of conus medullaris and thickness of FT. The structure of FT and associated malformations were also identified using MRI. But MRI was the standard method of follow-up in all patients. The treatment is mainly surgical in children with TCS [26]. Untethering is generally performed only if there are clinical signs or symptoms of deterioration. In secondary TCS, the surgery involves opening the scar formation from the prior closure down to the covering dura mater. Sometimes a small part of the laminae are removed to obtain better exposure or to decompress the spinal cord and cauda equina. The dura is then opened, and the spinal cord and rootlets are gently dissected away from the scarred attachments to the surrounding dura. Once the spinal cord is freed from all its scarred attachments, the dura and the wound are closed. In primary TCS, the aim of surgery is to release the spinal cord by cutting the FT. It is essential to properly identify the FT and sacral rootlets during the surgery [17, 27]. Neuromonitorization is crucial for a safe and effective surgery [5]. Laminotomy should be performed to identify the FT and rootlets. Solmaz et al. [26] analyzed the surgical results of 49 pediatric patients with TCS and they emphasized that the only way to prevent a recurrence in a detethered cord is to be certain that the neural elements remain free circumferentially with a patent CSF circulation. FT is especially important during the surgery of TCS. This is a fibrovascular band extending from the conus medullaris to the coccyx. It has no elasticity during the intrauterine life and this may cause TCS during childhood and adolescence. Kural et al. [17] showed the lack of elastic fibers and type I collagen in the uterine life. Cutting of the FT is the important part of TCS surgery. It is easy to make the decision of cutting when the FT is thick or lipomatous. But in normal size and appearance, it is difficult to decide for cutting the FT. Selcuki et al. [23] stated that the FT should be cut in TCS even if it has a normal appearance during surgery. In our series, we cut the FT in all cases in order to achieve appropriate spinal cord release. The children return to their normal daily activities within a few days or weeks after surgery. Recovery of neurological and urological functions depends upon the degree and length of preoperative levels [9, 31]. The complication rate of the untethering surgery is usually between 1 and 2 %. Complications include CSF collection and leakage, infection, hematoma, and neural damage to the spinal cord or rootlets,

which may result in leg and foot weakness or urological dysfunctions [20]. Children usually require only one surgical procedure for TCS [26]. In our series, CSF collection was the lonely complication of TCS surgery. Most of the children tolerate well the surgical treatment and improve or become stabile with regard to their preoperative level of neurological or urological function. There is a risk of re-tethering of the spinal cord as the child gets older. Therefore, it is important to monitor carefully the children and follow up them using MRI and electrophysiological techniques. Since the symptoms of re-tethering can occur during the growing of children, 10 to 20 % of patients require repeated surgery for re-tethering [26]. Duraplasty is an important factor to prevent the re-tethering of the spinal cord [20, 21]. In our series, re-tethering was detected in 12 patients during the follow-up period, we re-operated them to release the spinal cord. In conclusion, each child with TCS should be individualized for the surgical treatment. Good neurological and radiological assessments are essential for an accurate diagnosis. More clinical series with larger patient population are needed to ensure better clinical outcome. Conflict of interests The authors declare no conflict of interest.

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