Prognostic indicators of surgical outcome in painful foot drop: a systematic review and meta-analysis

Factors associated with improvement in tibialis anterior weakness due to lumbar degenerative disease

BACKGROUND

The weakness of the tibialis anterior remains to be a controversial topic. There has been no study that used electrophysiological assessment of the function of the lumbar and sacral peripheral motor nerves. The aim is to evaluate surgical outcomes in patients with weakness of the tibialis anterior using neurological and electrophysiological assessments.

METHODS

We enrolled 53 patients. Tibialis anterior weakness was quantified by muscle strength, as assessed using a manual muscle test on a scale of 1 through 5, with scores <5 indicating weakness. Postoperative improvement in muscle strength was classified as excellent (5 grades recovered), good (more than one grade recovered), or fair (less than one grade recovered).

RESULTS

Surgical outcomes for tibialis anterior function were categorized as "excellent" in 31, "good" in 8, "fair" in 14 patients. Significant difference in outcomes were observed depending on diabetes mellitus status, type of surgery, and the compound muscle action potentials amplitudes of the abductor hallucis and extensor digitorum brevis (p < 0.05). Surgical outcomes were classified into two groups, patients with excellent and good outcomes (Group 1) and patients with fair outcome (Group 2). Using the forward selection stepwise method, sex and the compound muscle action potentials amplitudes of the extensor digitorum brevis were identified as significant factors for their positive association with Group 1 status. The diagnostic power of the predicted probability was as high as 0.87 in terms of area under curve of the receiver operating characteristic curve.

CONCLUSIONS

There was a significant correlation between the prognosis of tibialis anterior weakness and sex and the compound muscle action potentials amplitude of extensor digitorum brevis, suggesting that recording the compound muscle action potentials amplitude of extensor digitorum brevis will aid the outcome assessment of future surgical interventions for tibialis anterior weakness.

A meta-analysis of prognostic factors in surgical treatment of foot drop due to lumbar degenerative diseases

Objective

Lumbar decompression surgery is an effective treatment for foot drop caused by LDD, but there is controversy about the prognostic factors affecting its efficacy. This study aimed to investigate the factors influencing the surgical outcome of foot drop due to LDD.

Methods

A systematic database search of PubMed, Embase, Web of Science, Cochrane Library and Clinical Trials was performed for relevant articles published until May 2022. Two reviewers independently screened the literature, extracted data, and evaluated the quality of the studies based on the inclusion and exclusion criteria. The quality of the studies was evaluated using the Newcastle-Ottawa Scale (NOS), and STATA 16.0 software was used for meta-analysis.

Results

A total of 730 relevant articles were initially identified and 9 articles were finally included in this study for data extraction and mea-analysis. The results of metaanalysis showed that patients with preoperative moderate muscle strength (2-3/5 on the Medical Research Council scale) had better prognosis compared to those with severe muscle weakness. Additionally, the presence of diabetes mellitus was associated with a poorer prognosis for patients with foot drop due to LDD. The OR values (95%CI) of these two factors were 5.882 (4.449, 7.776) and 5.657 (2.094,15.280) respectively.

Conclusions

Patients with moderate muscle strength have a better prognosis compared to those with severe muscle weakness. The presence of diabetes mellitus is associated with a poorer prognosis for patients with foot drop due to LDD. These factors should be considered when predicting the surgical outcome of foot drop due to LDD.

Management strategies for the painless foot drop: a systematic review of the literature

PURPOSE

Foot drop can uncommonly be a painless presenting symptom of degenerative spinal disorders. This systematic review aimed to summarise the literature on the management and outcomes of patients with a painless foot drop.

METHODS

We performed a systematic review of PubMed, EMBASE and Medline according to PRISMA guidelines. All studies published after 1980 in English referring to adult patients with a painless foot drop were included. Exclusion criteria included opinion based reports, review articles and articles in which foot drop was not caused by degenerative pathology of the thoracolumbar spine.

RESULTS

Of 62 included patients, 30 (48.4%) were male with an average age of 48.7 years (range 27-84). The mean duration of symptoms was 69.0 days (1-700). 98.8% were managed operatively. 46 (74.2%) patients had symptomatic improvement, with 41 (66.1%) having a post-intervention MRC power grading of 3 or above. Patients with a pre-procedure MRC 0 had a higher median increase in MRC post-procedure than those with MRC > 0. Of two studies comparing painful and painless symptoms, painless foot drop patients were less likely to recover to MRC equal to or over 3 than those with painful symptoms OR 0.31 (95% CI 0.04-2.65).

CONCLUSION

This systematic review and meta-analysis demonstrates a role for surgery in facilitating the neurological recovery of patients with a painless foot drop. Large randomised controlled studies are required to characterise the role of operative intervention in these patients and compare outcomes between patients with painless and painful foot drop.

A national survey on the management of foot drop secondary to lumbar degenerative disease in the United Kingdom

PURPOSE

There is considerable variation in the management of foot drop secondary to lumbar degenerative disease (LDD) that occurs between centres and surgeons (spinal surgeons and neurosurgeons). The lack of standardised practice reflects the paucity in evidence base for management of this condition. In this survey, we aimed to assess current practice in the UK and identify the areas of variation.

METHODS

A case-based survey was distributed to members of the Society of British Neurological Surgeons and British Association of Spine Surgeons through an online questionnaire. The survey consisted of 10 questions designed to determine the management of foot drop secondary to LDD.

RESULTS

A total of 163 responses were collected among UK neurosurgeons and spinal surgeons with good geographical representation. 92% were Consultants. 86% of the respondents would offer surgery. The indication for offering surgery varied but 54% of respondents would offer surgery to patients who present with a painful foot drop. There was a huge variation in offering surgery dependent on the grade of weakness. The strongest prognostic indicator predicted was duration of weakness (92%). The timing of intervention was wide-ranging in the responses received. Almost all responded that they would be willing to participate in a prospective study in the future to determine best practice.

CONCLUSIONS

This survey highlights the significant variability in management of foot drop secondary to LDD amongst consultant surgeons within the UK. It is also suggestive of a weak evidence base and indicates an urgent need for a high quality national prospective study.

A Novel Capsule Lumbar Interbody Fusion (CLIF) in Treating Foot Drop due to Lumbar Degenerative Diseases: a Prospective, Observational Study

Objective

This present study aimed to explore the clinical effects of a novel capsule lumbar interbody fusion (CLIF) on foot drop due to lumbar degenerative diseases.

Methods

Between June 2018 and January 2019, a total of 27 patients admitted to our department with lumbar degenerative diseases with associated foot drop were prospectively enrolled. Given the selection of surgical technique, patients were divided into traditional TLIF group and CLIF group. We assessed patients' neurological status using JOA and VAS score, tibialis anterior muscle strength using MMT score, diameter and hemodynamic parameters of the L5 nerve root using intraoperative ultrasonography (IoUS), and related radiological parameters of the lumbar spine. Operation time, blood loss, and surgery-associated complications were also recorded.

Results

The median duration of follow-up was 150 (6–1460) months. At the final follow-up, all patients acquired satisfactory improvement of neurological function. However, patients in the CLIF group showed better early recovery of foot drop three months after operation than those in the TLIF group, with 75% excellent rate. In addition, IoUS suggested that the diameter and hemodynamic parameters of the L5 nerve root were improved better in the CLIF group, which may suggest the correlation between the recovery of foot drop and the status of L5 nerve root. No severe complications were encountered with CLIF.

Conclusions

Our preliminary study revealed that the axial tension of L5 nerve root may be involved in the pathological mechanism of foot drop. The novel technique of CLIF can shorten the lumbar spine and can be effective and safe for the treatment of foot drop due to lumbar degeneration-related diseases.