Inactivation of spinal cord stimulator implanted pulse generators after elective surgery: an under-recognized problem.

STUDY DESIGN: We retrospectively analyzed a database of implanted pulse generators (IPGs) for spinal cord stimulation (SCS) implanted by a single surgeon (NDT). We additionally report a series of five illustrative patient cases. OBJECTIVES: The electronics of SCS IPGs are susceptible to damage when implanted patients undergo surgery. Some SCSs have a dedicated surgery mode, while others recommend turning the SCS off to protect it from damage. IPG inactivation may require resetting or replacement surgery. We aimed to explore the prevalence of this real-world problem which has not been studied. SETTING: Pittsburgh, Pennsylvania. METHODS: Using a single surgeon SCS database, we identified cases of IPG inactivation after a non-SCS surgery and analyzed the management. We then reviewed the charts of five illustrative cases. RESULTS: Among 490 SCS IPG implantations between 2016-2022, 15 (3%) of the 490 patients' IPGs became inactivated after another non-SCS surgery. 12 (80%) required surgical IPG replacement, while 3 (20%) were able to have their IPG function restored non-operatively. In cases analyzed thus far, surgery mode was often not activated prior to surgery. CONCLUSION: SCS IPG inactivation by surgery is not a rare problem and is presumably engendered by monopolar electrocautery. Premature IPG replacement surgery carries risks and reduces the cost-effectiveness of SCS. Awareness of this problem may prompt more preventative measures to be taken by surgeons, patients, and caretakers, and encourage technological advances to render IPGs less vulnerable to surgical tools. Further research is needed to determine what quality improvement measures could prevent electrical damage to IPGs.

Paddle Lead Spinal Cord Stimulation in the Morbidly Obese Patient Population: Outcomes and Complications in a Single-Surgeon Cohort.

BACKGROUND: Paddle lead spinal cord stimulation (SCS) is used to treat refractory chronic pain. Morbidly obese patients seek SCS to reduce chronic pain. However, these patients face worse surgical outcomes, and the SCS literature has not evaluated safety and efficacy in this patient population. This study is the largest single-surgeon case series to date on morbidly obese patients with paddle lead SCS implantations. The primary objective is to report postoperative complication rates in morbidly obese patients receiving SCS implants. The secondary objective is to report patient-reported pain scores and Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference and physical function scores in these patients. METHODS: A retrospective chart review was conducted. The patient charts were reviewed from the day of procedure consent to 6 months postop. Demographic information, pain scores, PROMIS scores, neurological complications, infections, and wound complications were documented. RESULTS: Sixty-seven patients were included. The mean preoperative BMI was 44.47 ± 4.02 kg/m2. The mean age was 58.9 ± 11.4 years old. There were no neurological complications. 3/67 (4%) developed culture-positive infections. Nine out of sixty-seven (13%) patients developed superficial wound dehiscence without underlying infection. The mean postop PROMIS physical function score was 31.6 ± 6.2 (n = 16) and the mean post-op PROMIS pain interference score was 64.0 ± 6.4 (n = 16). There was a reduction in pain scores, from 7.9 ± 1.7 preop to 5.7 ± 2.5 postop (n = 22, P = 0.004). CONCLUSIONS: Paddle lead SCS implantation is safe for morbidly obese patients. The only minimal-risk complications present were postoperative infections and wound dehiscence. Surgical care can be modified to further reduce the rates of infection and dehiscence.

Spinal cord stimulation: A novel approach to pain management in Dercum's disease.

Background: Dercum's Disease (DD) is a rare chronic pain syndrome in which patients experience extreme burning pain associated with subcutaneous lipomatous tissue deposits. These patients may also present with; weakness, psychiatric symptoms, metabolic derangements, sleep disturbance, impaired memory, and easy bruising. Common risk factors for DD include: obesity, Caucasian race, and female sex. The etiology of DD remains under debate while it has proven highly resistant to treatment (i.e., requiring high doses of opioids for adequate pain management). Case Description: A 48-year-old female with DD and a prior spinal cord stimulator (SCS) placed for chronic back pain, presented with recurrent back pain, and increased falling. Surgery to replace her SCS resulted in improvement in her back pain and a decreased incidence of falls. Furthermore, she noticed significant improvement in the burning pain attributed to her subcutaneous nodules; this most markedly occurred at and below the level of stimulator placement. Conclusion: A 48-year-old female with the extremely rare condition, DD experienced dramatic reduction in her pain following the successful revision of her SCS.

Foraminal stenosis and radiculopathy secondary to tophaceous gout: illustrative case.

BACKGROUND: Tophaceous gout is a severe form of gout that results in the formation of large nodules, or tophi, in the affected joints and surrounding tissues. Gouty tophi in the spine have a constellation of presentations that often mimic other pathologies and may not be easily discernable from more common pathologic processes. OBSERVATIONS: A 47-year-old female with a history of chronic renal disease, obesity, gout, inflammatory polyarthritis, and multiple sclerosis presented with 6 months of low-back pain and lumbar radiculopathy affecting the right lower extremity. A lumbar magnetic resonance imaging study revealed right foraminal stenosis and spondylolisthesis at levels L4-5. An intraspinal extradural mass was noted adjacent to the traversing right L5 and exiting right L4 nerve roots. A bilateral decompressive laminectomy, facetectomy, and foraminotomy of L4-5 was performed. A calcific, chalky-white mass was discovered in the foramen, and pathology determined the specimen to be a gout tophus. Postoperatively, the patient endorsed the resolution of her preoperative symptoms, which have not returned on follow-up. LESSONS: Reports of gouty depositions compressing the spinal cord in the current literature are relatively rare. Although the diagnosis of gouty tophi can only be confirmed histologically, patient history may serve as a helpful diagnostic tool.

Shoe Tread Wear Occurs Primarily during Early Stance and Precedes the Peak Required Coefficient of Friction.

Worn shoes contribute to injuries caused by slip-and-fall accidents. The peak required coefficient of friction (RCOF) has been associated with tread wear rate. However, the temporal relationship between RCOF and shoe wear is unknown. The purpose of this study was to determine whether the contact region at the time of peak RCOF is consistent with the region of shoe wear. The shoe contact region at peak RCOF was imaged by frustrated total internal reflection. Images of worn tread after months of use were captured. The worn tread region was more posterior than the contact region at RCOF and did not correlate with the contact region at the time of RCOF. The contact regions observed during earlier stance (within 83 ms of heel contact) were more consistent with the worn region, suggesting that RCOF may not directly cause tread wear. These results serve to motivate future studies to identify early-stance gait parameters associated with tread wear development.

Johnny on the Spot-Chronic Inflammation Is Driven by HMGB1.

Although much has been made of the role of HMGB1 acting as an acute damage associated molecular pattern (DAMP) molecule, prompting the response to tissue damage or injury, it is also released at sites of chronic inflammation including sites of infection, autoimmunity, and cancer. As such, the biology is distinguished from homeostasis and acute inflammation by the recruitment and persistence of myeloid derived suppressor cells, T regulatory cells, fibrosis and/or exuberant angiogenesis depending on the antecedents and the other individual inflammatory partners that HMGB1 binds and focuses, including IL-1ß, CXCL12/SDF1, LPS, DNA, RNA, and sRAGE. High levels of HMGB1 released into the extracellular milieu and its persistence in the microenvironment can contribute to the pathogenesis of many if not all autoimmune disorders and is a key factor that drives inflammation further and worsens symptoms. HMGB1 is also pivotal in the maintenance of chronic inflammation and a "wound healing" type of immune response that ultimately contributes to the onset of carcinogenesis and tumor progression. Exosomes carrying HMGB1 and other instructive molecules are released and shape the response of various cells in the chronic inflammatory environment. Understanding the defining roles of REDOX, DAMPs and PAMPs, and the host response in chronic inflammation requires an alternative means for positing HMGB1's central role in limiting and focusing inflammation, distinguishing chronic from acute inflammation.