Diagnosis and surgical treatment of terminal syringomyelia within spinal cord combined with tethered cord syndrome

Abstract

Objective To summarize the clinical manifestations, imaging characteristics and experience of surgical treatment of spinal cord terminal syringomyelia with tethered cord syndrome (TCS).  Methods and Results Clinical data of 10 patients with spinal cord syringomyelia combined with TCS surgically treated under microscope from January 1999 to March 2014 in our hospital were retrospectively analyzed. There were 3 males and 7 females with average age of 15.06 years old (ranged from 2 to 35 years old). The course of disease ranged from 3 months to 20 years (average 42.17 months). Among those patients, one patient presented hydromyelia, 8 patients suffered from meningeal cyst within the sacral canal, and one patient were concurrent with sacral dermal sinus. The weakness of lower extremities, especially distal limbs, was the main clinical manifestation. Five patients were accompanied with bowel and bladder dysfunction and 5 patients with sensory disturbance below the level of syringomyelia, especially hypesthesia. Preoperative MRI showed conus medullaris disappeared at the end of spinal cord, and there was fluid signal in the lower spinal cord with hypo-intensity signal in T₁WI and hyper-intensity signal in T₂WI without enhancement. All patients underwent surgical procedures. Under microscope, filum terminale was cut off, drainage was performed, meningeal cyst within the sacral canal was removed, and tethered cord was released. The success rate of operations was 100%. The duration of surgery ranged from 1.52 to 3.07 h (average 2.15 h), with average intraoperative blood loss 220 ml (ranged from 100 to 410 ml). The tethering filum had been totally resected and histological examination showed typical filum tissue in all cases. No operative complication was found. Visual Analogue Scale (VAS) score was decreased, and the lower limbs weakness as well as bowel and bladder dysfunction was gradually relieved after operation. The period of follow-up was ranged from 6 months to 14.50 years (average 6.10 years). All patients presented neurological intactness (McCormick gradeⅠ), recovery of conus medullaris, rising of the end of spinal cord, no recurrence of syringomyelia with favorable alignment of spine during follow- up period.  Conclusions Terminal syringomyelia in the spinal cord with TCS is rarely occurred and characterized by chronic dysfunction of spinal cord and nerve. The manifestation in MRI imaging is characterized by low level of spinal cord, disappearing of conus medullaris, long T₁ and long T₂ signal of filum terminale and spinal cord, and no enhancement of capsule wall. The surgical treatment includes resection of filum terminale, drainage of the cerebrospinal fluid (CSF) in syringomyelia, and de-tethering of the spinal cord under microscope. The outcome is satisfactory.

DOI: 10.3969/j.issn.1672-6731.2016.03.006