Dorsal paddle leads implant for spinal cord stimulation through laminotomy with midline structures preservation

The deep and the deeper: Spinal cord and deep brain stimulation for neuropathic pain

Neuropathic pain occurs in people experiencing lesion or disease affecting the somatosensorial system. It is present in 7 % of the general population and may not fully respond to first- and second-line treatments in up to 40 % of cases. Neuromodulation approaches are often proposed for those not tolerating or not responding to usual pharmacological management. These approaches can be delivered surgically (invasively) or non-invasively. Invasive neuromodulation techniques were the first to be employed in neuropathic pain. Among them is spinal cord stimulation (SCS), which consists of the implantation of epidural electrodes over the spinal cord. It is recommended in some guidelines for peripheral neuropathic pain. While recent studies have called into question its efficacy, others have provided promising data, driven by advances in techniques, battery capabilities, programming algorithms and software developments. Deep brain stimulation (DBS) is another well-stablished neuromodulation therapy routinely used for movement disorders; however, its role in pain management remains limited to specific research centers. This is not only due to variable results in the literature contesting its efficacy, but also because several different brain targets have been explored in small trials, compromising comparisons between these studies. Structures such as the periaqueductal grey, posterior thalamus, anterior cingulate cortex, ventral striatum/anterior limb of the internal capsule and the insula are the main targets described to date in literature. SCS and DBS present diverse rationales for use, mechanistic backgrounds, and varying levels of support from experimental studies. The present review aims to present their methodological details, main mechanisms of action for analgesia and their place in the current body of evidence in the management of patients with neuropathic pain, as well their particularities, effectiveness, safety and limitations.

Development of a Modified Bayonet Forceps for Improving Steerability of Paddle Lead Electrodes During Spinal Cord Stimulator Surgery: A Technical Note

BACKGROUND AND OBJECTIVE

Despite recent advancements in spinal cord stimulation (SCS) technology, the surgical instrumentation for placement of SCS paddle leads remains suboptimal. Therefore, we developed a novel instrument to improve the steerability of SCS paddle leads during surgical placement.

METHODS

A review of existing literature was performed to analyze workflow deficiencies in the standard instrumentation of SCS paddle lead placement. After a period of adaptation and iterative feedback with a medical instrument company, a new instrument was developed, tested at benchtop, and successfully incorporated into the surgical routine.

RESULTS

A standard bayonet forceps was modified to include hooked ends and a ribbed surface, providing the surgeon with greater control over the paddle lead. The new instrument also included bilateral metal tubes starting approximately 4 cm proximal from the edge of the forceps. The bilateral metal tubes, through which the SCS paddle lead wires are passed, serve as anchors to keep the wires away from the incision site. In addition, it permitted the paddle lead to assume a bent configuration, reducing its overall size and allowing it to be placed through a smaller incision and laminectomy. The modified bayonet forceps was successfully used intraoperatively for placement of SCS paddle lead electrodes in several surgeries.

CONCLUSION

The proposed modified bayonet forceps increased steerability of the paddle lead, facilitating optimal midline placement. The bent configuration of the device facilitated a more minimally invasive surgical approach. Future studies are needed to validate our single-provider experience and evaluate the impact of this new instrument on operating room efficiency.

Incidence of Lead Migration With Loss of Efficacy or Paresthesia Coverage After Spinal Cord Stimulator Implantation: Systematic Review and Proportional Meta-Analysis of Prospective Studies and Randomized Clinical Trials

OBJECTIVE

The objective of this meta-analysis was to approximate the incidence of overall lead migration, clinically significant lead migration, and asymptomatic lead migration in patients who have undergone spinal cord stimulator implantation.

MATERIALS AND METHODS

A comprehensive literature search was performed for studies published before May 31, 2022. Only randomized controlled trials and prospective observational studies with more than ten patients were included. Two reviewers analyzed the articles from the literature search for final inclusion, after which, study characteristics and outcome data were extracted. The primary dichotomous categorical outcome variables were the incidence of overall lead migration, clinically significant lead migration (defined as lead migration resulting in loss of efficacy), and asymptomatic lead migration (defined as lead migration discovered incidentally on follow-up imaging) in patients with spinal cord stimulator implant. Freeman-Tukey arcsine square root transformation for meta-analysis of proportions using random effects (DerSimonian and Laird method) was used to calculate incidence rates for the outcome variables. Pooled incidence rates and 95% CIs were calculated for the outcome variables.

RESULTS

Fifty-three studies met the inclusion criteria, with a total of 2932 patients having received spinal cord stimulator implants. The pooled incidence of overall lead migration was 9.97% (95% CI of 7.62%-12.59%). Only 24 of the included studies commented on the clinical significance of reported lead migrations, of which every lead migration was clinically significant. In these 24 studies, 96% of the reported lead migrations required a revision procedure or explant. Unfortunately, no studies that reported lead migration commented on asymptomatic lead migrations; therefore, the incidence of asymptomatic lead migrations could not be defined.

CONCLUSIONS

This meta-analysis found that the rate of lead migration in patients who have received spinal cord stimulator implants is approximately one in ten patients. This likely closely approximates the incidence of clinically significant lead migration owing to the included studies not routinely performing follow-up imaging. Therefore, lead migrations were primarily discovered owing to loss of efficacy, and no included studies clearly reported asymptomatic lead migration. The results of this meta-analysis can be used to inform patients more accurately on the risks and benefits of spinal cord stimulator implantation.

A case study of percutaneous epidural stimulation to enable motor control in two men after spinal cord injury

Two persons with chronic motor complete spinal cord injury (SCI) were implanted with percutaneous spinal cord epidural stimulation (SCES) leads to enable motor control below the injury level (NCT04782947). Through a period of temporary followed by permanent SCES implantation, spinal mapping was conducted primarily to optimize configurations enabling volitional control of movement and training of standing and stepping as a secondary outcome. In both participants, SCES enabled voluntary increased muscle activation and movement below the injury and decreased assistance during exoskeleton-assisted walking. After permanent implantation, both participants voluntarily modulated induced torques but not always in the intended directions. In one participant, percutaneous SCES enabled motor control below the injury one-day following temporary implantation as confirmed by electromyography. The same participant achieved independent standing with minimal upper extremity self-balance assistance, independent stepping in parallel bars and overground ambulation with a walker. SCES via percutaneous leads holds promise for enhancing rehabilitation and enabling motor functions for people with SCI.

Should Posterior Midline Structures Be Preserved in Decompression Surgery for Lumbar Spinal Stenosis?: A Systematic Review and Meta-analysis

STUDY DESIGN

This was a systematic review and meta-analysis study.

OBJECTIVE

The purpose of this study is to evaluate the available evidence on the preservation of posterior midline structures in decompression surgery for lumbar spinal stenosis (LSS).

SUMMARY OF BACKGROUND DATA

The gold-standard treatment for LSS refractory to conservative management is facet-preserving laminectomy. The question remains whether the midline structures should be preserved in decompression surgery for LSS.

MATERIALS AND METHODS

We performed a systematic review of the Medline, PubMed, Embase, and Cochrane databases in search of published reports comparing midline structure preservation (MSP) and conventional laminectomy (CL) for LSS. The population was divided into 2 groups: (1) MSP group (intervention) and (2) CL group (control). The various outcome parameters including blood loss, operation time, hospital stay, back and leg pain, functional scores including Oswestry Disability Index (ODI) score, Japanese Orthopedic Association score, and 36-Item Short Form Survey (SF-36) scores, satisfaction, and instability rates were analyzed. Data were extracted and aggregated for meta-analysis.

RESULTS

Of the published reports, 16 met our inclusion criteria with an aggregated 540 in the intervention and 538 in the control groups, respectively. The aggregated data demonstrated patients undergoing MSP had significantly decreased back pain Visual Analog Scale compared with CL, regardless of time after surgery ( P =0.007). The MSP group also showed a significantly lower Oswestry Disability Index score and SF-36 Mental Component Summary score ( P =0.005 and 0.03, respectively) and longer 6-month walking distance ( P <0.00001). The patient satisfaction rate was significantly higher in the MSP group ( P =0.02), and the instability rate was significantly lower in the MSP group compared with the CL group ( P <0.0001). At 3 days after surgery, MSP significantly decreased the level of creatinine phosphokinase ( P <0.00001). Regarding intraoperative blood loss, hospital stay, leg pain Visual Analog Scale score, Japanese Orthopedic Association score, and SF-36 Physical Component Summary score, there were no significant differences between the 2 groups. However, MSP showed significantly higher operation time ( P =0.04).

CONCLUSIONS

We concluded despite heterogenous and limited data, this study suggests that preservation of midline structure leads to less severe back pain, better functional recovery, and satisfaction rate. Meanwhile, it decreases creatinine phosphokinase level and instability rate.

LEVEL OF EVIDENCE

Level III-therapeutic.

Placement of surgical spinal cord stimulation (SCS) leads using spinal process splitting laminotomy (SPSL): Technical note

OBJECTIVE

Spinal Cord Stimulation (SCS) has become an established method within the therapy of chronic pain allowing for significant pain relief. Surgical leads usually have to be implanted via a surgical procedure involving uni- or bilateral muscle detachment and partial laminectomy.

METHODS

We present the application of a novel minimal invasive microsurgical approach for lead placement which combines the beneficial advantages of anatomical midline lead placement whilst preserving the midline structures, avoiding muscle detachments and thus ensuring spinal stability: spinal process splitting laminotomy (SPSL).

CONCLUSION

The spinal process splitting laminotomy (SPSL) technique can be successfully applied to introduce the surgical leads for spinal cord stimulation.

Efficacy analysis of two surgical treatments for thoracic and lumbar intraspinal tumours

BACKGROUND

Surgery remains the main curative option for the treatment of intraspinal tumour. The purpose of the present study was to analyze the clinical outcomes of laminoplasty with process-lamina complex replantation compared with laminectomy with pedicle screw fixation for intraspinal tumours.

METHODS

In our retrospective analysis, 27 patients received tumour resection surgery by laminoplasty with reconstruction plate fixation and 32 patients received laminectomy with pedicle screw fixation. All patients were followed up for at least 1 year. Data, including surgical time, blood loss, volume of drainage, drainage time, hospital stay, complications, and neurological status were compared. In addition, imaging evaluation was also included.

RESULTS

Patients in the laminoplasty group had lower blood loss (laminoplasty group: 281.5 ± 130.2 mL; laminectomy group: 450.0 ± 224.3 mL; p = 0.001), shorter surgical time (laminoplasty group: 141.7 ± 26.2 min, laminectomy group: 175.3 ± 50.4 min; p = 0.003), lower volume of drainage (laminoplasty group: 1578.9 ± 821.7 mL, laminectomy group: 2621.2 ± 1351.0 mL; p = 0.001), shorter drainage time (laminoplasty group: 6.6 ± 2.5 days, laminectomy group: 9.7 ± 1.8 days; p = 0.000), and a shorter hospital stay (laminoplasty group: 16.9 ± 4.9 days, laminectomy group: 21.0 ± 4.4 days; p = 0.002) compared with patients in the laminectomy group. There were significant differences of oswestry dysfunction index (ODI) between the two groups at 12 months postoperatively (p = 0.034). The incidence of secondary spinal stenosis in the laminoplasty group was significantly reduced (p = 0.029).

CONCLUSIONS

Laminoplasty in intraspinal tumour resection has a lower blood loss and volume of drainage, shorter surgical time and hospital stay as advantages over the standard laminectomy technique. Moreover, laminoplasty can effectively avoid iatrogenic spinal canal stenosis and thus enhancing functional recovery of spinal cord.

Long-term Outcomes After Replacement of Percutaneous Leads With Paddle Leads in a Retrospective Cohort of Patients With Spinal Cord Stimulation Systems

BACKGROUND:

Although the long-term outcomes for spinal cord stimulation (SCS) have been reported, long-term outcomes of patients who underwent revisions of the SCS with paddle leads are lacking.

OBJECTIVE:

To report the long-term outcomes of 39 patients who had percutaneous SCS revised with a new paddle lead.

METHODS:

Baseline and follow-up mail-in questionnaires assessed pain and disability levels with numerical rating scales, somatotopical overlap between SCS-related paresthesias and areas of chronic pain, and overall satisfaction. Analysis was performed with regard to age, sex, diagnosis, duration of disease, number of surgical revisions, complications, and interval between surgeries.

RESULTS:

After surgical revision, 20 patients (50%) had at least a 3-point reduction in the numerical rating scale. Greater pain reduction was correlated with better coverage (P = .001). Coverage area was greater in patients with a single revision than in patients with multiple revisions (P = .01). Good satisfaction was reported by 25 patients (62.5%) who indicated that they would undergo the procedure again in order to achieve the same results. These patients had significantly greater pain reduction (P = .001) and better coverage (P = .002) than patients who reported otherwise. No other major complication occurred.

CONCLUSION:

Revision of percutaneous SCS systems with implantation of a new paddle lead is safe and more effective in patients who have undergone not more than 1 prior revision.