Comparison of facet fusion rates and clinical outcomes between cortical bone trajectory screw and percutaneous pedicle screw fixation for degenerative lumbar spondylolisthesis

BACKGROUND CONTEXT

Cortical bone trajectory (CBT) screws have been introduced as an alternative technique for pedicle screw (PS) insertion because they have greater contact with the cortex and a greater uniaxial pullout load than traditional PS. CBT screwing can also minimize muscle dissection. However, CBT screws and traditional PSs have not yet been compared in terms of fusion rates and clinical outcomes for particular operative procedures.

PURPOSE

This study aimed to assess the fusion rate and clinical outcomes of facet fusion (FF) fixed with CBT screws (CBT-FF) and to compare them with those of FF fixed with percutaneous PS (PPS-FF).

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

Records of 68 patients who underwent CBT-FF for single-level degenerative lumbar spondylolisthesis (DLS) with at least 1 year of follow-up were retrospectively reviewed. The control group comprised 143 patients who underwent PPS-FF under the same conditions.

OUTCOME MEASURES

Computed tomography was performed to confirm fusion. Therapeutic effectiveness was assessed as a clinical outcome using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), Roland-Morris Disability Questionnaire (RMDQ), and visual analog scale (VAS) preoperatively and 1 year postoperatively. The rate of revision surgery was also calculated. Intraoperative blood loss was measured.

METHODS

Fusion rate, clinical outcomes, revision surgery rate, and intraoperative blood loss of CBT-FF and PPS-FF were compared.

RESULTS

The CBT-FF and PPS-FF fusion rates were 91.2% and 90.1%, respectively. The JOABPEQ category scores demonstrated therapeutic effectiveness in 74.5% and 77.1% of the patients for low back pain; the corresponding proportions for walking ability were 84.7% and 89.3%, respectively. No significant differences in therapeutic effectiveness were observed for any category, including the RMDQ and VAS scores for buttock and lower limb pain. Three patients required revision surgery for adjacent segment disease between 6 months and 3.5 years after CBT-FF (revision surgery rate, 4.4%), whereas the revision surgery rate for PPS-FF was 6.3% (9/143 cases). Average intraoperative blood loss was significantly less in the CBT-FF group than in the PPS-FF group.

CONCLUSIONS

Both procedures were equally useful in terms of fusion rate and clinical outcomes for DLS management.

Quantitative evaluation of the lumbar ligamentum flavum using MRI T2-mapping: Efficacy of its clinical application in patients with lumbar spinal stenosis

OBEJECTIVE

To perform a magnetic resonance imaging T2-mapping of the ligamentum flavum in healthy individuals and patients with lumbar spinal stenosis scheduled for surgery and compare the T2 relaxation times.

SUBJECTS AND METHODS

The T2 relaxation time of the ligamentum flavum was compared among 3 groups, healthy young individuals (H group (age< 50)), healthy middle-aged and older individuals (H group (age≥50)), and patients with lumbar spinal stenosis (L group). Additionally, the thickness of the ligament was measured in the axial image plane, and the occupied area ratio of each fiber was measured by staining the surgically obtained ligament, and each was correlated with the T2 relaxation time. We also evaluated the adhesion of the ligamentum flavum with the dura mater during the surgery.

RESULTS

The T2 relaxation times were significantly prolonged in H group (age ≥50) and L group (P < 0.001) compared to H group (age<50). The relationship between collagen fiber and T2 relaxation times was significantly positive (r = 0.720, P < 0.001). Moreover, the relaxation times were significantly prolonged in those with adhesion of the ligamentum flavum with the dura mater (P < 0.05). The cut-off for the relaxation time was 50 ms (sensitivity: 62.50%, false positive rate: 10.8%).

CONCLUSION

Healthy middle-aged and older individuals and patients with lumbar spinal stenosis and adhesion of the ligamentum flavum with the dura mater have prolonged T2 relaxation times. Hence, the adhesion between the ligamentum flavum and dura mater should be considered in cases with a relaxation time ≥50 ms.

Efficacy and Safety of Condoliase Disc Administration as a New Treatment for Lumbar Disc Herniation

Introduction

Condoliase is a newly approved drug that improves symptoms associated with lumbar disk herniation (LDH) by intradiscal administration. This study aimed to evaluate the mid-term outcomes of condoliase injection, examine the adverse events, including cases that required surgery after condoliase administration, and verify cases in which condoliase could be effective.

Methods

We enrolled patients with LDH who were treated conservatively for at least six weeks and received condoliase. We assessed the visual analog scale (VAS) score, Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, Oswestry Disability Index, disk height, and disk degeneration for up to 6 months, and we examined the complications. Furthermore, a 50% or more improvement in leg pain VAS score was considered effective. Factors related to symptom improvement were investigated by determining whether lower limb pain improved in six months.

Results

In total, 84 patients were recruited (52 men, 32 women; mean age, 44.2 ± 17.1 [16-86 years]). The duration of illness was 6.7 ± 6.8 (1.5-30) months. All patient-based outcomes significantly improved at 4 weeks after the administration compared with pretreatment. The intervertebral disc height decreased significantly at four weeks after condoliase administration compared with that before administration. Progression of intervertebral disc degeneration occurred in 50% of the patients. Eleven patients underwent herniotomy due to poor treatment effects. Moreover, treatment in 77.4% of the patients was considered effective. A logistic regression analysis revealed that L5/S1 disk administration (p = 0.029; odds ratio, 5.94; 95% confidence interval, 1.20-29.45) were significantly associated with clinical effectiveness.

Conclusions

Condoliase disk administration improved pain and quality of life over time. Condoliase disk administration was more effective in L5/S1 intervertebral administration.

Good clinical outcomes in nonunion cases after facet fusion with a percutaneous pedicle screw system for degenerative lumbar spondylolisthesis

There are many satisfactory long-term outcomes after posterolateral fusion (PLF) for degenerative lumbar spondylolisthesis (DLS); nonunion cases have also achieved good clinical outcomes. Facet fusion (FF), a minimally invasive evolution of PLF, also resulted in good clinical outcomes. We aimed to assess the course of nonunion cases after FF and determine whether the nonunion cases achieved good clinical outcomes. We retrospectively reviewed the records of 136 patients who underwent FF for DLS. Range of motion (ROM) at the fused level was measured using a flexion-extension lateral radiograph preoperatively and 1 year postoperatively. Patients were classified into the Fusion or Unconfirmed Fusion group by computed tomography (CT) 1 year postoperatively. Furthermore, patients in the Unconfirmed Fusion group were classified into the Delayed Union or Nonunion group depending on the confirmation status of FF upon the following CT. The average preoperative ROM and clinical outcomes were compared between the three groups. The Fusion, Delayed Union, and Nonunion groups had 109, 14, and 13 patients, respectively. In the Nonunion group, the average ROM significantly decreased from 13.0° preoperatively to 4.9° postoperatively. There was a significant difference in the average preoperative ROM between the groups. The larger the preoperative ROM, the fewer facets fused. There was no significant difference in clinical outcomes between the groups. Five patients (3.7%) required revision surgery for adjacent segment disease 1-5.5 years after FF. Even nonunion cases after FF achieved good clinical outcomes, likely because the unstable spondylolisthesis was stabilized. FF did not require revision surgery for nonunion itself.

Pedicle screw shift without loosening following instrumented posterior fusion: limitations of pedicle screw fixation

The disc angle at the fused segment is extended in operative prone position, but eventually returns to preoperative neutral position within 6 months to 1 year. This study aimed to assess pedicle screw (PS) shift without loosening to identify the mechanism of the change in disc angle after posterior fusion for degenerative lumbar spondylolisthesis (DLS). Sixty-three consecutive patients who underwent facet fusion for L4 single-level DLS were retrospectively reviewed using computed tomography (CT) immediately after surgery and 6 months postoperatively. Twenty-two patients (88 PSs) in whom the disc angle had decreased by more than 4° at 6-month postoperative radiographic follow-up were selected to more readily identify and quantify PS shift. Six patients with PS loosening and/or nonunion were excluded. We reconstructed a CT plane, vertical to the cranial endplate of the vertebrae and passing through the cannula used for percutaneous PSs. Angle α, which is formed by the cranial endplate and the cannula on this plane, was measured. A change in angle α of more than 2° between the immediate postoperative period and the 6-month follow-up was defined as a PS shift. Angle α did not change by more than 2° in any of the 44 PSs in the upper vertebrae of the fused segment. In the lower vertebrae, angle α changed by more than 2° in 22 of 44 PSs. The change in angle α in the lower vertebrae (average, 2.3°) was significantly greater than that in the upper vertebrae (average, 0.2°) (P < 0.0001). The change in the disc angle was not relevant to clinical outcomes assessed by the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire, the Roland-Morris Disability Questionnaire, and the visual analogue scale. The disc angle at the fused segment returned to preoperative neutral position due to PS shift without loosening, mainly in the lower vertebrae. PS shift is caused by bone remodeling in response to biomechanical load, similar to that in orthodontic tooth movement. As PS has limited ability to maintain a lordotic disc angle, even with the insertion of a cage, lumbar alignment will return to preoperative neutral position owing to cage subsidence or adjacent segment disease. These findings might indicate that it is not necessary to correct the spinal alignment for DLS.

Animated respiratory movement of a spinal intradural arachnoid cyst visualized by intraoperative ultrasonography

This study aims to describe the animated respiratory movement of a spinal intradural arachnoid cyst visualized by intraoperative ultrasonography. A 69-year-old man with a spinal arachnoid cyst of the thoracic spine presented with gait disturbance. Magnetic resonance images showed a mild anterior displacement and flattening of the spinal cord at T4-T5. We performed ultrasonography before incision of the dura during the operation and observed the movement of the cyst consisting of not only pulsation in accordance with the cardiac cycle but also rhythmic expansion and contraction in accordance with the respiratory cycle. In the inspiratory phase, the cyst gradually expanded and pulsated in accordance with the cardiac cycle. In the expiratory phase, the cyst gradually contracted with the same pulsation. After resection of the cyst, the patient's neurological improvements were excellent. To our knowledge, this is the first report of animated respiratory movement of a spinal arachnoid cyst visualized by intraoperative ultrasonography. Although cine magnetic resonance imaging can detect spinal intradural arachnoid cysts preoperatively, intraoperative ultrasonography is useful for close analysis of their movement and pathology. Considering the dynamic compression mechanism revealed in this study, we think that an early operation should be performed for such cysts.

Incidence of nocturnal leg cramps in patients with lumbar spinal stenosis before and after conservative and surgical treatment

PURPOSE

To examine the effects of conservative and surgical treatments for nocturnal leg cramps in patients with lumbar spinal stenosis (LSS). Nocturnal leg cramps is frequently observed in patients with peripheral neuropathy. However, there have been few reports on the relationship between nocturnal leg cramps and LSS, and it remains unknown whether conservative or surgical intervention has an impact on leg cramps in patients with LSS.

MATERIALS AND METHODS

The subjects were 130 LSS patients with low back and leg pain. Conservative treatment such as exercise, medication, and epidural block was used in 66 patients and surgical treatment such as decompression or decompression and fusion was performed in 64 patients. Pain scores and frequency of nocturnal leg cramps were evaluated based on self-reported questionnaires completed before and 3 months after treatment.

RESULTS

The severity of low back and leg pain was higher and the incidence of nocturnal leg cramps was significantly higher before treatment in the surgically treated group compared with the conservatively treated group. Pain scores improved in both groups after the intervention. The incidence of nocturnal leg cramps was significantly improved by surgical treatment (p=0.027), but not by conservative treatment (p=0.122).

CONCLUSION

The findings of this prospective study indicate that the prevalence of nocturnal leg cramps is associated with LSS and severity of symptoms. Pain symptoms were improved by conservative or surgical treatment, but only surgery improved nocturnal leg cramps in patients with LSS. Thus, these results indicate that the prevalence of nocturnal leg cramps is associated with spinal nerve compression by LSS.

Conservative and surgical treatment improves pain and ankle-brachial index in patients with lumbar spinal stenosis

PURPOSE

The pathological mechanism of lumbar spinal stenosis is reduced blood flow in nerve roots and degeneration of nerve roots. Exercise and prostaglandin E1 is used for patients with peripheral arterial disease to increase capillary flow around the main artery and improve symptoms; however, the ankle-brachial index (ABI), an estimation of blood flow in the main artery in the leg, does not change after treatment. Lumbar spinal nerve roots contain somatosensory, somatomotor, and unmyelinated autonomic nerves. Improved blood flow by medication with prostaglandin E1 and decompression surgery in these spinal nerve roots may improve the function of nerve fibers innervating muscle, capillary, and main vessels in the lower leg, resulting in an increased ABI. The purpose of the study was to examine whether these treatments can improve ABI.

MATERIALS AND METHODS

One hundred and seven patients who received conservative treatment such as exercise and medication (n=56) or surgical treatment (n=51) were included. Low back pain and leg pain scores, walking distance, and ABI were measured before treatment and after 3 months of conservative treatment alone or surgical treatment followed by conservative treatment.

RESULTS

Low back pain, leg pain, and walking distance significantly improved after both treatments (p<0.05). ABI significantly increased in each group (p<0.05).

CONCLUSION

This is the first investigation of changes in ABI after treatment in patients with lumbar spinal stenosis. Improvement of the spinal nerve roots by medication and decompression surgery may improve the supply of blood flow to the lower leg in patients with lumbar spinal stenosis.

Evaluation of low back pain using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire for lumbar spinal disease in a multicenter study: differences in scores based on age, sex, and type of disease

BACKGROUND

The Japanese Orthopaedic Association (JOA) has investigated the JOA Back Pain Evaluation Questionnaire (JOABPEQ) to evaluate several aspects of low back pain in patients. The score includes five categories (25 items) selected from the Roland Morris Disability Questionnaire and Short Form 36, and a visual analogue scale. Japanese physicians have recently used these scores to evaluate back pain; however, the efficacy has not been fully explored in large-scale studies. In the current study, we used the JOABPEQ to evaluate lumbar spinal disease in 555 patients (with lumbar disc herniation, lumbar spinal stenosis, and lumbar disc degeneration/spondylosis) in multiple spine centers and compared the results based on age, sex, and type of disease.

METHODS

A total of 555 patients who had low back or leg pain were selected in 22 hospitals in Chiba Prefecture. Spine surgeons diagnosed their disease type based on symptoms, physical examination, radiography images, and magnetic resonance imaging. In all, 486 patients were diagnosed with spinal stenosis (239 patients), disc degeneration/spondylosis (143 patients), or disc herniation (104 patients). The other 69 patients were diagnosed with spondylolysis (16 patients) or other diseases (53 patients). The pain score in all patients was evaluated using the JOABPEQ (from 0 to 100, with 0 indicating the worst pain).

RESULTS

The age of the patients was 56.1 +/- 13.3 years (mean +/- SD); the age of patients in the disc herniation and disc degeneration/spondylosis group was significantly lower than that in the spinal stenosis group. The average JOABPEQ scores in all patients were, for low back pain, 47.1; lumbar function, 53.6; walking ability, 54.8; social life function, 48.7; and mental health, 48.3. The low back pain score in men was significantly worse than that in women. In contrast, the mental health score in women was significantly higher than that in men. The low back pain score in patients <40 years old and the walking ability score in patients >65 years old were significantly lower than those scores in other patients. Based on the disease type, low back pain, lumbar function, social life function, and mental health scores for patients with disc herniation were significantly worse than for those with spinal stenosis.

CONCLUSION

JOABPEQ scores were evaluated for several lumbar diseases. The average of five categories of JOABPEQ scores in all patients was similarly distributed. However, the average scores in the five categories were significantly different depending on age, sex, and type of disease. Compared with prior mass data (baseline data on the observational cohort of the Spine Patient Outcomes Research Trial in the United States), many data were similar based on the type of disease in the current study. Furthermore, the JOABPEQ is easy to use compared with the SF-36. Hence, we concluded that the JOABPEQ could be used worldwide as a tool for evaluating low back pain.

Effects of hypoxia on the ventral root motor-evoked potential in the in vitro spinal cord preparation

STUDY DESIGN

This study investigated the effects of hypoxia and glucose on motor functions of spinal cord, monitoring ventral root motor-evoked potential in the in vitro cervical cord preparations.

OBJECTIVE

To study ischemia-induced changes in ventral root motor-evoked potential of spinal cord.

SUMMARY OF BACKGROUND DATA

Previous studies demonstrated ischemic changes caused by local circulatory impairment might be a major pathophysiologic basis of neuron damage in cord compression.

METHODS

Ventral root motor-evoked potential elicited by stimulation of ventrolateral funiculus was recorded from the ventral root in the isolated spinal cord preparations obtained from a newborn rat. The preparations were exposed to artificial cerebrospinal fluid equilibrated with severe or mild hypoxia for 90 minutes. Inhibitory and excitatory neurotransmitter antagonists were added to artificial cerebrospinal fluid to investigate synaptic transmission. The artificial cerebrospinal fluids containing various concentrations of glucose were used to study the glucose's effects.

RESULTS

Ventral root motor-evoked potential consisted of the early and late components, which were excitatory transsynaptic potentials. The amplitudes were increased in the early phase of severe hypoxia and declined in the prolonged exposure. In mild hypoxia, there was a sustained increase of the amplitudes. The application of inhibitory neurotransmitter antagonists abolished the augmentation of the amplitudes in the early phase of severe hypoxia. Hypoxia without glucose accelerated hypoxic change.

CONCLUSION

Inhibitory synaptic transmission was depressed preferentially in the early phase of severe hypoxia or in mild hypoxia. Excitatory and inhibitory transmissions were suppressed in prolonged severe hypoxia. Glucose deficiency aggravated hypoxic inhibition of synaptic transmissions.