Presentation of Tethered Cord Syndrome With a Normally Positioned Conus in Children

Symptoms and Signs

The authors’ study did not include patients who presented solely with urological dysfunction. Instead, all patients had other manifestations of occult spinal dysraphism, such as cutaneous anomalies, orthopedic problems, or neurological dysfunction (35).

• 40% weak: The most common complaint was lower extremity weakness, occurring in 40%.
• 40% with bladder dysfunction: Bladder dysfunction was the other common complaint and was found in 40% of the patients. Although the study’s description of the tethered cord with a conus in normal position did include patients with urinary incontinence, only four patients had bladder dysfunction. Three of the four patients had improved bladder function at postoperative follow-up. Other sporadic reports in the literature have shown that urinary complaints, especially incontinence, are dealt with by sectioning the filum terminale in the face of a conus that is in a ‘normal’ position. Khoury et al. (10) have discussed sectioning of the filum for the above scenario. In their first publication, 23 children with a normally positioned conus on myelography had filum release surgery. Approximately 72% of them had resolution of their preoperative incontinence. Some groups recommend surgery if neurogenic bladder is evident on cystometrogram in the absence of MRI and other clinical findings.  This has been a contentious issue, which will hopefully be resolved over time. The authors would stress that the possibilities of all other potential sources of incontinence be exhausted and in conjunction with a urologist experienced with such testing. Again, the rarity of the normally positioned conus and TCS is stressed.
• 30% with bowel dysfunction: Bowel dysfunction occurred in 30%.
• 46% with cutaneous signs: Only six of 13 patients had cutaneous signatures: four had lumbosacral hemangiomas, one had a lumbosacral subcutaneous lipoma, and one had a midline lumbar skin tag.
• 39% with leg deformities: Five of 13 patients presented with lower extremity abnormalities, with three having leg-length discrepancy and two having foot deformities.
• Incidence of these presenting abnormalities similar to TCS with low conus: When the authors compared patients with TCS without and with an abnormally displaced conus, the following was observed: cutaneous signatures of occult spinal dysraphism (46% versus 52%, respectively), abnormalities of the extremities (39% versus 32%), vertebral abnormalities (100% versus 95%), dysraphic abnormalities (62% versus 78%), and neurological abnormalities (77% versus 87%).
• Others have reported similar presentations: Moufarrij et al. (18) reported a series of patients with findings of tethered spinal cord in which three patients had a cord termination at the L2 vertebral level. Only one of these patients had a fatty filum terminale. Presenting symptoms in these three children were gait disturbance with lower extremity weakness, leg cramps with foot inversion, and progressive kyphoscoliosis. Intraoperatively, these patients were noted to have the cut ends of their fila retract 1–3 cm. Raghavan et al. (21) reported 25 patients with tethered spinal cord in which four had coni superior to the middle segment of the L2 vertebrae. Two of the four presented with urinary incontinence and fatty fila. Tonsillar ectopia was found in five of nine patients with imaging of the craniocervical junction.

Patterns of Evolution

• Increased neurological dysfunction

Time for Evolution

• Variable

Intervention

Preparation for definitive intervention, nonemergent

• Imaging: Plain radiographs of the lumbar spine and a spinal MRI are needed for surgical evaluation.
• Urological evaluation: Urodynamics are performed to establish baseline bladder function (30).

Admission Orders

• Routine preoperative orders