RESUMO
We experienced the rare complication of a vertebral fracture that was caused by implant removal after bony fusion had been achieved in a patient who underwent spine-shortening osteotomy (SSO) for tethered cord syndrome (TCS). We propose that the removal of the implant used for SSO should be contraindicated. The patient (a 27-year-old female) presented to our institution with a history of progressive severe lower back pain, gait disturbance, and urinary incontinence. As an infant, she had undergone surgery for spina bifida with lipoma. Magnetic resonance imaging of the spine revealed tethering of the spinal cord to a lipoma. We performed SSO at the level of the L1 vertebra level. After spine shortening and fixation using a posterior approach, the L1 vertebral body was completely removed anteriorly and replaced with a left iliac bone graft. The patient's symptoms improved after surgery. After bony fusion was achieved after surgery, we decided to remove the spinal implant after we explained the advantages and disadvantages of the procedure to the patient. We performed implant removal surgery safely 2 years later; however, the patient complained of severe lower back pain 10 days after the surgery without any history of trauma. Reconstruction computed tomography showed fracture of the grafted vertebra. We performed a repeat posterior fixation, which relieved the lower back pain; she has experienced no complications in the subsequent 5 years. In summary, we report a case of a rare complication of the fracture of a grafted vertebra after removal of an implant used in SSO for TCS. Spinal stability could not be maintained without the spinal posterior implant after SSO. Postoperative fracture after spinal implant removal is rare but possible, and patients must be informed of this potential risk.
RESUMO
BACKGROUND: Miyakoshi et al. reported three cases of tethered cord syndrome treated by spine-shortening vertebral osteotomy, which provided relief of the patients' symptoms with no complications. Although the details of these cases were described in a previous report, the surgical technique was not thoroughly explained. In the present report, we describe the details of our procedure with reference to a fourth case. CASE PRESENTATION: A 47-year-old Asian woman was admitted to our hospital with a 1-year history of worsening leg numbness and urinary dysfunction. Magnetic resonance imaging revealed a low-lying conus medullaris extending to the level of S2 and surrounded by fat tissue at that level. We diagnosed her condition as adult tethered cord syndrome, and spine-shortening vertebral osteotomy was planned. The target level for the osteotomy was L2. Bilateral pedicle screw implants were placed at L1 and L3 using an anterior-posterior image intensifier. In this procedure, it is essential to use monoaxial screws inserted exactly parallel to the rostral endplates of each vertebral body; this ensures appropriate alignment between the L1 caudal endplate and the L2 osteotomy surface. The upper one-third of the lamina of L2 was resected, and the bilateral two-thirds of the pedicle of L2 was removed with a surgical air drill. After exposure of the lateral side of the L1-2 disc, discectomy was performed with a knife and curette. Following complete discectomy of L1-2, the upper vertebral body of L2 was removed with a surgical air drill. After complete removal of the vertebral body, a straight rod was connected to two screws and applied pressure between the screws. Two polyethylene tapes were applied to the L2 lamina and bilateral rods. CONCLUSION: Spine-shortening osteotomy that preserves the caudal one-third of the pedicle and lamina with one-above and one-below instrumentation successfully reduced the spinal cord tension without causing neural damage.