Decision-making process in patients with lumbar spinal canal stenosis

Revision Surgery for Short Segment Fusion Influences Postoperative Low Back Pain and Lower Extremity Pain: A Retrospective Single-Center Study of Patient-Based Evaluation

Introduction

Patients treated with revision surgery after lumbar decompression with fusion typically have persistent low back pain and lower extremity numbness compared with patients treated with only primary surgery. No well-designed study has investigated the persistence and degree of pain after revision surgery following instrumented operation. The purpose of this study is to compare residual pain among patients who underwent reoperation and those who underwent only primary surgery for lumbar degenerative disorder using patient-based evaluation.

Methods

We reviewed 350 consecutive patients (143 men, 207 women, mean age 63 years) treated with primary lumbar instrumented surgery between October 2010 and February 2014 at our institution and followed up for ≥2 years postoperatively. Patients were categorized into three groups based on number of levels fused: 1-segment, 2-segment, and ≥3-segment fusion (1F, 2F, and ≥3F groups, respectively). We used the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and visual analog scales (VASs) for low back pain and lower extremity pain to evaluate pain intensity pre- and postoperatively.

Results

Salvage surgery for late-phase complications was required in 5 cases (2.4%), 6 cases (11.3%), and 11 cases (12.1%) in the 1F, 2F, and ≥3F groups, respectively. In the 1F and 2F groups, patients treated with revision surgery had unsatisfactory improvement in the pain domain of JOABPEQ and VASs for low back pain and lower extremity pain compared with patients with only primary short fusion surgery. The ≥3F group showed no significant differences between patients who underwent reoperation and those who underwent only primary surgery.

Conclusion

Low back pain and lower extremity pain often persist after revision surgery in patients treated with short fusion (≤2-segment) operation. We need to follow pain states in such patients.

Dural sac cross-sectional area and morphological grade show significant associations with patient-rated outcome of surgery for lumbar central spinal stenosis

PURPOSE

Lumbar central spinal stenosis (LSS) is one of the most common reasons for spine surgery in the elderly patient. Magnetic resonance imaging (MRI) represents the gold standard for the assessment of LSS and can be used to obtain quantitative measures of the dural sac cross-sectional area (DCSA) or qualitative measures (morphological grades A-D) of the rootlet/cerebrospinal fluid ratio. This study investigated the intercorrelation between these two MRI evaluation methods and explored their respective relationships with the patient baseline clinical status and outcome 12 months after surgery.

METHODS

This was a retrospective analysis of prospectively collected data from 157 patients (88 male, 69 female; age 72 ± 7 years) who were undergoing first-time surgery for LSS. Patients with foraminal or isolated lateral stenosis were excluded. The Core Outcome Measures Index (COMI) was completed before and 12 months after surgery. Preoperative T2 axial MRIs were blinded and independently evaluated for DCSA and morphological grade. Spearman rank correlation coefficients described the relationship between the two MRI measures of stenosis severity and between each of these and the COMI baseline and change-scores (pre to 12 months' postop). Multiple logistic regression analysis (controlling for baseline COMI, age, gender, number of operated levels, health insurance status) was used to analyse the influence of stenosis severity on the achievement of the minimum clinically important change (MCIC) score for COMI and on global treatment outcome (GTO).

RESULTS

There was a correlation of ρ = -0.69 (p < 0.001) between DCSA and morphological grade. There was no significant correlation between COMI baseline scores and either DCSA or morphological grades (p > 0.85). However, logistic regression revealed significant (p < 0.05) associations between stenosis ratings and 12-month outcome, whereby patients with more severe stenosis (as measured using either of the methods) benefited more from the surgery. Patients with a DCSA <75 mm² or morphological grade D had a 4-13-fold greater odds of achieving the MCIC for COMI or a "good" GTO, compared with patients in the least severe categories of stenosis.

CONCLUSIONS

Postoperative outcome was clearly related to the degree of preoperative radiological LSS. The two MRI methods appeared to deliver similar information, as given by the relatively strong correlation between them and their comparable performance in relation to baseline and 12-month outcomes. However, the qualitative morphological grading can be performed in an instant, without measurement tools, and does not deliver less clinically useful information than the more complex and time-consuming measures; as such, it may represent the preferred method in the clinical routine for assessing the extent of radiological stenosis and the likelihood of a positive outcome after decompression.

Preliminary Results of Relationship between Preoperative Walking Ability and Magnetic Resonance Imaging Morphology in Patients with Lumbar Canal Stenosis: Comparison between Trefoil and Triangle Types of Spinal Stenosis

Study Design

Cross-sectional.

Purpose

To examine the relationship between magnetic resonance imaging (MRI) morphology stenosis grades and preoperative walking ability in patients with lumbar canal stenosis (LCS).

Overview of Literature

No previous study has analyzed the correlation between MRI morphology stenosis grades and walking ability in patients with LCS.

Methods

This prospective study included 98 consecutive patients with LCS who were candidates for surgery. Using features identified in T2-weighted axial magnetic, stenosis type was determined at the maximal stenosis level, and only trefoil and triangle stenosis grade types were considered because of sufficient sample size. Intraobserver and interobserver reliability were assessed by calculating weighted kappa coefficients. Symptom severity was evaluated via the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ). Walking ability was assessed using the Self-Paced Walking Test (SPWT) and JOABPEQ subscales. Demographic characteristics, SPWT scores, and JOABPEQ scores were compared between patients with trefoil and triangle stenosis types.

Results

The mean patient age was 58.1 (standard deviation, 8.4) years. The kappa values of the MRI morphology stenosis grade types showed a perfect agreement between the stenosis grade types. The trefoil group (n=53) and triangle group (n=45) showed similar preoperative JOABPEQ subscale scores (e.g., low back pain, lumbar function, and mental health) and were not significantly different in age, BMI, duration of symptoms, or lumbar stenosis levels (all p>0.05); however, trefoil stenosis grade type was associated with a decreased walking ability according to the SPWT and JOABPEQ subscale scores.

Conclusions

These findings suggest preoperative walking ability is more profoundly affected in patients with trefoil type stenosis than in those with triangle type stenosis.

Outcomes of Surgery in Patients with Lumbar Spinal Canal Stenosis: Comparison of Three Types of Stenosis on MRI

The aim of the study was to compare outcome of surgery in patients with lumbar canal stenosis (LCS) based on magnetic resonance imaging (MRI) morphology. This was a prospective study of 96 consecutive patients who underwent surgery at 143 levels of LCS (from L3-L4 to L5-S1). Using patterns on T2 axial MRI, the type of stenosis was determined for each patient. The Swiss Spinal Stenosis Score (SSS) was used to evaluate patients’ functionality and outcomes. The definition of treatment success was based on the criteria developed by Stucki et al. Demographic characteristics and post-operative outcomes were compared between trefoil, triangular, and pin-hole groups. Finally, correlation between SSS score and the MRI morphology was assessed. The mean age of patients was 58.4 (SD = 8.9) years. Post-treatment satisfaction was observed in a large portion of the patients (87.5%). The trefoil group (n = 44), triangular group (n = 38), and pin-hole group (n = 14) had similar pre-operative Swiss Spinal Stenosis Score and were not significantly different in age, operative time, blood loss, duration of symptoms, walking distance, symptom severity and physical function (all p>0.4). No correlation between SSS score and the MRI morphology was observed. The findings suggest that the type of stenosis based on magnetic resonance imaging morphology is not indicative of surgical outcome among lumbar canal stenosis patients who undergo surgery at 1-year follow-up.