Neural tube defects including the tethered cord syndrome (TCS) are still rising in developing countries like Pakistan, even though their prevalence has decreased worldwide. TCS is a stretch-induced functional disorder of the spinal cord with its caudal part anchored by an inelastic structure, which results in characteristic symptoms and signs [1]. This can be secondary to heterogeneous group of disorders, such as spinal lipomas, lipomatous filum, split cord malformations, and meningomyelocele. It typically occurs in children, and it is rare in adults [2]. The abnormally low position of the conus medullaris may lead to neurological, musculoskeletal, urological, orthopedic, or gastrointestinal abnormalities [13]. The clinical presentation of TCS is broad and varies with age at presentation as well as underlying cause. A physical examination has a key role in determining the diagnosis of TCS. Although TCS is a well-known entity, it continues to pose challenges regarding diagnosis and management [4]. In 1976, Hoffman et al. coined the term "tethered spinal cord" in patients with a low lying conus medullaris with a thickened filum [3]. More recently, there have been descriptions of TCS in which patients are described to have the conus medullaris in a normal position on imaging but presenting with signs and symptoms consistent with TCS [5]. Due to the variety of lesions and clinical presentations and the absence of high-quality clinical data, the decision regarding treatment is difficult [6]. The basic goal of surgical treatment in TCS is to improve or stabilize deficits in the symptomatic patient and to prevent future deficits in the asymptomatic patient [3].

Our objective was to look at the different presentations of TCS and their surgical outcome, according to the presenting complaints and pathologies.

We retrospectively reviewed 50 consecutive patients who were surgically treated for TCS at Liaquat National Hospital and Medical College, Karachi, from 2010 until 2014. Data was thoroughly reviewed and analyzed using IBM SPSS statistics ver. 21.0. Majority of our patients were between 0–15 years of age with the mean age of 4 years. The follow-up period of these patients was 12–48 months. The patients were assessed with respect to power, gait, urinary and bowel control, and deformity. The presenting complaints, associated pathologies, and postoperative improvements were documented. The Karachi TCS severity scale for clinical assessment (Table 1) [7] was used to assess patients preoperatively, and the scores were compared to postoperative changes. The chi-square test was used to determine significant associations between variables at a 5% significance level.

TCS patients ranged in age from 0–15 years, with a mean of 4 years. Eighteen patients were 0–2 years of age and 25 were 2–15 years of age. Of the 50 original patients, seven were lost during follow-up. The most common complaint (90%) was urinary sphincter problems. Thirty three patients presented with back swelling or any cutaneous symptom including lipomeningocele or previous myelomeningocele. Thirty two patients presented with progressive weakening of lower limbs. Twenty one patients had progressive scoliosis. Sixteen patients presented with progressive back or leg pain, with 14 patients presenting with Talipes equinovarus, seven with scissoring of feet and six patients were paraplegic. The presenting symptoms according to the age group are shown in Fig. 3

The majority of the patients had four distinct pathologies: thickened filum terminale, diastematomyelia, lipoma and myelomeningocele (Fig. 4). All patients had combinations of four pathologies (Fig. 5). Thirty patients had tethering of the spinal cord at L3–S2 level that was apparent on resonance imaging (MRI). Five patients had tethering at L1–L2 and only one patient had tethering at the dorsal level.

The results of Karachi TCS severity scale for clinical assessment are shown in Fig. 6.

Neural tube defects are still common in the developing world, due to lack of antenatal awareness and care [89]. In third world countries, TCS goes undiagnosed for years due to lack of tertiary care hospital care setups in rural areas. Although the incidence of spinal dysraphism has reduced [3], it is still significantly high in our part of the world because of the lack of awareness of risk factors [89]. The risks include folic acid deficiency [10], mothers very young or very old in age, toxic medications, obesity, multiple gestation, anti-epileptic medications, zinc deficiency, and ingestion of excessive tea in the first trimester of pregnancy [9].

Patients with TCS can present with a wide variety of signs and symptoms in combination with cutaneous, orthopedic, spinal, anorectal and urological abnormalities, as well as pain [3]. In our experience, the common presenting complaints were sphincter dysfunction, lower limb motor deficits, cutaneous signs at the lumbosacral region, and progressive leg pain. The other symptoms included, scoliosis, scissoring of feet, contractures, and Talipes equinovarus.

Urinary dysfunction is one of the most common finding in TCS. The use of the urodynamic test is helpful is diagnosing urinary dysfunction and assessing the patients pre and post operatively, especially in infants, in whom the clinical diagnosis of urinary dysfunction can be difficult [3]. Urinary abnormalities were the most common complaint found in patients 0–2 years of age (94%) and 2–15 years of age (95%). The majority of our findings were based on patient recognition and parental assessment of their child. We were not able to use the urodynamic test as a definitive assessment and diagnostic tool because a lot of our patients were from a low socioeconomic background, which was a major drawback in our study.

The neurological findings in patients with TCS are varied, and include motor weakness, gait abnormality, spasticity, complete paraplegia, hyper or hyporeflexia, muscular atrophy, and sensory dysfunction [3]. In our study, more than 80%of the patients had neurological finding including paraperesis (74%) and paraplegia (14%). Motor function was easily assessed, documented, and compared postoperatively. But, there was a discrepancy in documented reflexes in our series, so reflexes were not included in our score.

The cutaneous findings in TCS usually include lipomas, hypertrichosis, hemangiomas, cigarette burns, dermal sinus tracts, and meningocele [3]. Cutaneous findings were evident in 76%of our patients, and the literature suggests that cutaneous manifestations are present in 70% of the patients with spinal dysraphism. Orthopedic deformities are also commonly found in patients with TCS, such as leg length discrepancy, (talipes equinovarus, TEV), contractures, club foot, progressive scoliosis, and scissoring of the legs. In our series of patients, the most common orthopedic deformity was scoliosis (48%), followed by TEV (32%) and foot deformities (16%) (Fig. 8). In another study, scoliosis was documented in 25% of the cases and foot deformity was more commonly found [3]. Presently, scoliosis was more common among patients 2–15 years of age. Lower back pain and leg pain is more commonly found in adults with TCS [11].

TCS is usually associated with heterogeneous group of spinal dysraphism, such as diastematomyelia, lipoma, thickened filum, and myelomeningocele [12]. MRI is the modality of choice for evaluation of TCS [12] as it shows structural information required to assess, classify, and identify associated pathologies, and to plan treatment. Our patients had combinations of all four pathologies.

The surgical management of TCS remains controversial for many neurosurgeons. Patients with a significant abnormality, such as a lipomyelomeningocele and clear clinical deterioration,could be straightforward surgical candidates [6]. A recommended chief indication for surgery in tethered cord is progressive neurological deterioration [13]. In our series of patients, better postoperative outcome was attained for those with thickened filum terminale and diastematomyelia as compared to myelomeningocele and lipoma. This may be due to better neurology at the time of presentation. It is suggested that patients with diastematomyelia and thickened filum terminale with progressive neurology should be treated aggressively. Patients who present with paraperesis have a better outcome than those patients who present with paraplegia. Patients with subtle symptoms who are diagnosed and treated early would appear to have a better outcome.

In a study involving 60 TCS patients, improvement was noted in 78% and 83% of patients with back and leg pain, respectively [4]. Motor weakness stabilized or improved in only 27% and 64%, respectively [4]. Urological abnormalities improved in 50% of patients and remained stable in 45% [4]. Our series showed a similar trend of results in patients with back and leg pain, in which 93% improved and motor weakness stabilized and improved in 57% and 42%, respectively. Untethering in patients with bladder or bowel incontinence improved in 46% of the patients, but the extent of improvement varied depending on the preoperative symptoms and deficits. Undoubtedly, incontinence is the most serious symptom that can become quickly irreversible unless treated in the very early stage of TCS [1].

The overall outcome for patients with TCS (Fig. 7) was dependent on the severity of the preoperative symptoms. Of the 24 patients with TCS gait score of 0–2, 11 showed improvement postoperatively. Of the 19 patients who scored 3–4, 14 had improvement postoperatively. From the 17 patients who had TCS power score of 0–2, only eight improved postoperatively. Of the 26 patients with a TCS power score of 3–5, 17 showed improvement postoperatively. Of the 35 patients who had TCS urinary/bowel score of 0–1, 19 showed improvement, and of the eight patients with a score of 3–4, six improved. Out of the eight patients with TCS sensation score of 0, three improved. Finally, of the 35 patients with a score between 1–2, 24 showed improvement postoperatively.

The common postoperative complications of untethering include cerebrospinal fluid (CSF) leakage, wound infection, meningitis, bladder dysfunction, and neurological deterioration [314]. We encountered complications in seven patients, in which CSF leakage occurred in four patients, two patients had worsened urinary control, and postoperative infection. The CSF leak was surgically repaired in one of the patients, and the urinary control recovered in a patient over 6 months of follow-up. The patient with worsened urine control also had deterioration of left foot power postoperatively, but also recovered over next 2 months. The deterioration in neurology may have been because of the neural bands lying within the filum, which may have been sectioned, or because of manipulation and stretch of neural tissue during surgery.

Even though there is enormous data on TCS in children, there has yet to be a universal scale that can be applied to preoperative and postoperative assessment [15]. We modified a scale that was proposed on the basis of a clinical approach for TCS patients [7]. This includes gait, power, bowel/urine, and sensation. Gait was only applied when it could be assessed.

The study has some limitations. Itis retrospective, although the final follow-up was prospective in all patients. Even with a short follow-up with small numbers, we have shown that thickened filum terminale patients had best outcome, followed by diastematomyelia and lipoma. We used the Karachi severity scale of TCS to score clinical symptoms. A prospective long\-term study with large numbers of patients is underway with application of the Karachi TCS severity scale.

Neural tube defects have a major impact on the health and quality of life of affected children and their families. Fortification of flour with folic acid has significantly reduced the number of children with neural tube defects in all countries that have mandated it [10]. The approach is recommended in developing countriesto reduce the incidence of neural tube defects.

TCS is a common condition in third world countries. It is essential to diagnose and surgically treat TCS in the early stage. Untethering in patients with TCS improves or arrests the progression of neurological deterioration. Patients with diastematomyelia and thickened filum presenting with TCS have better outcome compared to patients with myelomeningocele or meningocele. Our modified Karachi TCS severity scale for clinical assessment is good way to standardize the preoperative and postoperative clinical findings. A larger prospective study is already underway at our institution to explore the predictive value of the scale.