Intractable Chronic Low-Back Pain Caused by Ligamentopathia Treated Using a Spinous Process Plate (S-plate).

We report a case of intractable chronic low-back pain in a gymnast that was caused by ligamentopathia in the interspinous region of the lumbar vertebrae. Sprained interspinous ligaments are a common mechanical cause of acute low-back pain in athletes. Although conservative therapy is generally effective in such cases, in this case it was not. The patient experienced severe low-back pain during lumbar flexion with tension between the L5/S interspinous ligaments. We performed interspinous fixation by using a spinous process plate system, which has been developed for short in situ fusions, and following which the low-back pain resolved. Conservative therapy for low-back pain caused by ligamentopathia is first-line choice, but interspinous fixation with instrumentation might be recommended in intractable cases with conservative therapy.

Introduction

The mechanical causes of back pain include muscle strain and iliac crest apophysitis, sprained interspinous ligaments and kissing spines, thoracic and lumbar Scheuermann’s disease, intervertebral disc injuries, leg-length discrepancies, and traumatic and stress fractures of the vertebral body or posterior elements.1–5 Sprained interspinous ligaments are a common mechanical cause of acute low-back pain in athletes;6–8 however, they rarely cause intractable chronic low-back pain.

Case

A 37-year-old man visited our neurosurgical unit with a 6-year-history of low-back pain. He had been a gymnast; however, he had quit gymnastics 6 years ago after having suffered from severe low-back pain during training. He had been treated with every mode of conservative therapy, but the pain was intractable. He could not sit for more than 5 minutes without experiencing pain, and this adversely affected his daily life and job.

The pain was located in the midline of the lower back region. Physical examination, showed maximum tenderness over the interspinous ligament between the spinous processes of the L5 and sacrum. The pain was exacerbated during lumbar flexion. X-ray studies of the lumbar spine showed no instability, and disc height and alignment were normal (Fig. 1). Magnetic resonance imaging (MRI) studies showed abnormal high intensity in the interspinous region (Fig. 2).

Figure 1.

X-ray films of the lumbar spine. A) Anteroposterior (A-P) view. Slight scoliosis can be seen. B) Lateral view with flexion. C) Lateral view with extension. These X-ray films show no instability, and the disc height and alignment are normal.

Figure 2.

MRI scans of the lumbar spine. A) A T1-weighted image. B) A T2-weighted image. MRI studies showed abnormal high intensity in the interspinous region.

We admitted him to our hospital and prescribed bedrest along with a brace. The patient was given injections of dexamethazone (8 mg) and 1% lidocaine (4 ml) in the interspinous lesion 4 times at intervals of 1 week, but this had no effect. We diagnosed the patient with intractable pain caused by ligamentopathia, which was exacerbated by the tension between the L5/S interspinous ligament, and performed interspinous fixation between the L5 and sacrum by using the S-plate (Kisco DIR Co. Ltd., Osaka, Japan) (Fig. 3); ceratite sticks (Kobayashi Pharmaceutical Co., Ltd, Osaka, Japan) were placed in the interlaminar space. The pain reduced remarkably after the surgery, and the plate was removed 6 months thereafter. The visual analogue scale (VAS) was assessed preoperatively and at the 1st, 3rd, 6th, 12th postoperative month for the low-back pain. The Oswestry Disability Index was assessed preoperatively and at the 12th postoperative month. The VAS score measured preoperatively, at the 1st, 3rd, 6th, 12th postoperative month improved significantly to 8.0, 3.0, 2.0, 2.0, 2.0, respectively. The Oswestry Pain Index remarkably improved from 80.0 preoperatively to 20.0 at the 12th postoperative month. The interspinous region was gently fixed without bony fusion, but with granulation after the surgery. The interspinous fixation has been maintained even after the removal of the plate. The granulation after the instrumentation surgery could maintain the fixation. The S-plate fixation procedure thus relieved the patient from his low-back pain.

Figure 3.

Post operative X-ray films. A) Anteroposterior (A-P) view. B) Lateral view. The S-plate was fixed between the L5 and sacrum and ceratite sticks were placed in the interlaminar space.

Discussion

Competitive and recreational athletes of all ages commonly experience back pain.6–8 However, the cause and location of the pain are frequently specific to the athlete’s age and sport activity performed. The most common mechanical causes of back pain include muscle strains and iliac crest apophysitis, sprained interspinous ligaments and kissing spines, thoracic and lumbar Scheuermann’s disease, intervertebral disc injuries, leg-length discrepancies, and traumatic and stress fractures of the vertebral body or posterior elements.1–5

The interspinous ligaments are the most common site of injury.6,7 Usually, patients experience acute onset of pain along the midline of the lower back. The pain is exacerbated during flexion of the lumbar spine. In most cases, tenderness, assessed by physical examination, is maximal over the interspinous ligaments, but the patient may also have accompanying paraspinous muscle spasms. The treatment for this condition is the same as that for muscle strain. Thus, complete bedrest and anti-inflammatory medications are advised.9,10 In this patient, these modes of conservative therapy were not effective, and thus, the chronic pain was intractable. We confirmed that the intractable pain was caused by ligamentopathia, which was exacerbated by the tension between the L5/S interspinous ligaments. We performed interspinous fixation by using the S-plate, and it has proven to be effective.

The interspinous stabilization system has been developed for short in situ fusions in select patients.11,12 In this fixation procedure, the spinous processes are secured between a pair of plates with screws; these plates are then fixed together by tightening the screws that extend through them. This technique is easy and safe and damage to the posterior soft tissue is lesser than that in the case of lateral mass screw fixation and pedicle screw fixation. Our patient was suffering from intractable lumbago caused by stretching of the L5/S interspinous ligament without any intervertebral instability. The S-plate fixation was suitable for this patient, because its use could secure the position of the spinous processes of the L5 and sacrum.

Conservative therapy is generally effective for low-back pain caused by ligamentopathia.13–15 In cases wherein conservative therapy is not effective and the pain is intractable, gentle interspinous fixation, such as that using the S-plate, might be effective. Conservative therapy for low-back pain caused by ligamenthopathia is first-line choice, but interspinous fixation with instrumentation might be recommended in intractable cases with conservative therapy.