Modulatory Effects of Stem Cells on Opioid Receptors and Neuroinflammation.

PURPOSE OF REVIEW: This narrative review examines stem cell therapy and its effect on opioid therapy in neuropathic pain. RECENT FINDINGS: Stem cell therapy has shown promise in neuropathic pain and opioid tolerance, with a notable common pathway (the P2X4 receptor). Opioid therapy frequently has poor efficacy in patients who suffer from neuropathic pain. There is evidence that the presence of neuropathic pain itself causes changes to the opioid receptor, decreasing the therapeutic potential of this modality. The efficacy of opioid therapy is further decreased in this patient population after chronic opioid exposure, which leads to opioid tolerance and in some cases opioid-induced hyperalgesia. There is growing evidence that stem cell therapy has potential to treat neuropathic pain and may simultaneously decrease opioid tolerance and hyperalgesia. Opioid-induced hyperalgesia occurs via mu-opioid receptor-dependent expression of P2X4 receptors on microglia. Intrathecal stem cell therapy provides analgesic properties due to the significant reduction of P2X4R expression in spinal cord microglia, thereby directly decreasing chronic neuropathic pain.

Subdural Collection Above the Surgical Site After Endoscopic Surgery: A Case Report.

Endoscopic decompression continues to expand its therapeutic scope in alleviating chronic back pain. Endoscopic decompressions are minimally invasive and have rare complications. This case details a unique occurrence of a subdural collection following an interlaminar endoscopic laminotomy, facetectomy, lateral recess, and left L5 decompression. The subdural collection manifested above the operative site, despite the absence of dural puncture during the intervention. Subsequent to the procedure, the patient reported significant pain relief and presented for a follow-up appointment, disclosing new symptoms which included new weakness in his hamstrings and burning pain in his bilateral feet. A repeat MRI revealed a subdural collection, the etiology of which remains unclear given the intact dura during the surgical procedure. The MRI showed no new herniation and had objective improvement where his decompression took place. While previous cases have documented subdural collections primarily in association with dural puncture, this instance is distinctive in that regard. An intriguing aspect specific to endoscopic procedures is the potential for injury related to irrigation pressure. This scenario raises the hypothesis of a hematoma formation within the subdural space, possibly due to trauma to bridging vessels between the dura and arachnoid membrane. Alternatively, an unexpected increase in intra-abdominal or thoracic pressure may have led to elevated spinal vessel pressure, particularly affecting radiculomedullary veins traversing both the subdural and subarachnoid spaces. Further investigation and clinical monitoring are warranted to elucidate the precise mechanism underlying this subdural collection and its implications for postoperative management.

Retrospective Review of the Efficacy of Lumbar Radiofrequency Ablation for Lumbar Facet Arthropathy: The Influence of Gender and Obesity.

BACKGROUND: Lumbar facet arthropathy is one of the leading causes of back pain. Lumbar radiofrequency lesioning is a therapy for lumbar facet arthropathy that uses heat to ablate the transmission of nerve signals from the medial branches of the spinal nerves associated with the corresponding painful lumbar joints. OBJECTIVES: The present investigation evaluated the outcomes of patients undergoing lumbar radiofrequency ablation at an academic pain program with a special focus on the influence of gender and obesity. STUDY DESIGN: Retrospective chart review. SETTING: Academic tertiary care center. METHODS: We reviewed the charts of 232 patients for age, body mass index, gender, other procedures, and complications, in addition to the primary outcome measurements of Visual Analog Scale pain scores, pain relief percentages, pain relief duration, and functional status improvement per patient report. Associations with outcomes were evaluated with correlations, t tests/analysis of variance, and c2 test. Influences on a change in Visual Analog Scale pain scores before and after treatment were assessed with linear regression. RESULTS: Patients had an average pain reduction of 76.6% (SD = 24.5) from the initial treatment and an average of 30.7 weeks (SD = 21.2) of pain relief from the initial treatment. A total of 83% of the patients reported an improvement in functional status from the initial treatment. Women (mean = 79.8%, SD = 21.4) had a slightly higher pain relief percentage than men (mean = 71.6%, SD = 28.1; P = 0.046). A higher body mass index was associated with less improvement in Visual Analog Scale maximum pain scores from before and after the procedure (b = 0.04; SE = 0.02; P = 0.042). LIMITATIONS: Our study is not a randomized controlled trial; however, based on the number of patients reviewed, our data provide important information regarding lumbar radiofrequency ablations. CONCLUSIONS: This study highlights significant effectiveness for patients undergoing lumbar radiofrequency ablations for lumbar facet joint pain. A variation in effectiveness appears to be influenced by gender and obesity, and therefore additional studies are warranted to further investigate these differences.

Endoscopic Spinal Decompression: A Retrospective Review of Pain Outcomes at an Academic Medical Center.

INTRODUCTION:  Spinal stenosis is a chronic, debilitating condition that is expected to affect an increasing number of people as the population ages. Symptomatic spinal stenosis, like other spine pathologies, including disc herniation and degenerative disc disease, traditionally required an open decompressive surgical approach if more conservative approaches failed. An emerging alternative has been developed to address the needs of this population of patients in the form of endoscopic spine surgery (ESS). Advantages of ESS include minimal tissue trauma, decreased risk of damage to the neurovascular structures, minimal epidural fibrosis/scarring, reduced hospital stay, early functional recovery, and improved cosmetic outcomes. The purpose of this study was to review the outcomes of patients undergoing transforaminal endoscopic spinal decompression at an academic pain program. METHODS: We conducted a retrospective review of electronic medical records with approval from the University of Florida Institutional Review Board (IRB #202001529). Twenty patients underwent successful transforaminal endoscopic lumbar spinal decompression surgery at UF Health Pain Medicine from July 1, 2019, to June 1, 2020. The majority of cases were performed at L4-5 (n = 14), followed by an equal number (n = 3) of cases at L3-4 and L5-S1. Preoperative and postoperative visual analog scale (VAS) pain scores from patients' pain clinic appointments were obtained from the electronic health records system to assess the intervention as a pain relief strategy. RESULTS:  Patients had an average pain reduction of 82% (SD = 31%), resulting in an average postoperative pain score of 1.8 (SD = 2.8) on a 10-point VAS. CONCLUSION:  This study highlights the benefits of endoscopic spine surgery for patients, including pain reduction and reduced scarring.

Ultrasound-Guided Regional Anesthesia Using a Head-Mounted Video Display: A Randomized Clinical Study.

BACKGROUND: Ultrasonography is increasingly being used in every field of medicine, especially regional anesthesia. To successfully perform the procedure, a knowledge of anatomy and ultrasonoanatomy as well as technical 3D hand-eye coordination skills are required. Medical practitioners who use ultrasound devices to perform regional blocks have to correlate the position of the ultrasound probe on the patient, needle position, and ultrasound picture. To achieve that, the practitioner has to intermittently look between the patient and the ultrasonography screen. This requires extra head rotations, increasing the time and complexity of the procedure. Newer technologies are available that can alleviate the need for these extra head movements, such as head-mounted displays (HMDs), which are connected to the ultrasonography machine and project the ultrasonography picture onto the HMD goggles so that the provider can see the monitor without unnecessary head rotations. OBJECTIVE: Our theory was that the use of the HMD goggles would decrease the overall procedure duration as well as provider head rotations. STUDY DESIGN: This was a randomized clinical study. SETTING: The research was conducted at an academic medical center at the University of Texas Medical Branch, Galveston, TX. METHODS: We secured Institutional Review Board (IRB) approval to perform the study. We chose an HMD, which can be mounted on the head like regular goggles. By connecting the HMD with the ultrasonography machine, the ultrasound picture can be projected directly in front of the physician's eyes. Twenty-four patients were randomized to receive a regional anesthetic performed by anesthesiology residents using a conventional ultrasound-guided approach or using the HMD in addition. We measured the number of attempts, head rotations, and time needed to obtain a satisfactory nerve stimulation in addition to outcomes and adverse effects. Our data were interpreted by our statistician with P < .05 indicating statistical significance. RESULTS: Regional anesthetics performed with the HMD were significantly faster (59.08 vs 175.08 seconds) with significantly fewer head movements (0.83 vs 4.75) and attempts (1 vs 1.42). There were no significant differences in patient demographics, type of regional anesthetic, level of resident training, or outcomes. No complications were noted. LIMITATIONS: A limitation of our research is that neither observers nor providers were blinded to the way blocks were performed. This would have been practically impossible because participants had to wear an HMD. CONCLUSIONS: The HMD could provide advantages in regional anesthesia by decreasing the time and attempts and improving ergonomics. These findings can be easily translated into other ultrasound- or optic/camera-guided procedures outside of regional anesthesia, such as vascular access or laparoscopic surgery.IRB: UTMB IRB #12-143.

Blood flow restriction exercise to attenuate postoperative loss of function after total knee replacement: a randomized pilot study.

Aging well is directly associated with a healthy lifestyle. The focus of this paper is to relate that attenuation of postoperative loss of muscle function after a total knee arthroplasty (TKA) is an important consideration. Because patients usually do not tolerate standard high-resistance exercise in the preoperative or postoperative period, they often experience a decline in strength and function. Therefore, we tested the feasibility and acceptability of an alternative low-resistance exercise protocol with blood flow restriction (BFR) using a tourniquet in the preoperative period for patients awaiting TKA. We recruited patients undergoing a TKA and randomized six to the BFR exercise for 4 weeks prior to surgery and four to standard of care (no exercise). We measured physical function using the Short Physical Performance Battery (SPPB), the 6-Minute Walk Test (6MWT), leg strength (peak torque), and pain (numerical pain score) 4 to 5 weeks preoperatively and 2 weeks postoperatively. The clinical management, e.g., anesthetic management, did not differ between groups. No complications were observed. Our findings demonstrate the feasibility and acceptability of the BFR intervention. Although preliminary and not powered for comparison, the BFR group demonstrated less decline in SPPB following surgery (-2.2, 95%CI:-4.4,0.1) compared to the no exercise group (-4.8, 95%CI:-7.8,-1.7). No differences were noted for the 6MWT, leg strength, and pain measurements. We conclude that preoperative low-resistance exercise using the BFR is feasible and acceptable, and this test warrants investigation as an intervention to potentially attenuate the postoperative loss of physical function after TKA.

Assessing the feasibility of using the short physical performance battery to measure function in the immediate postoperative period after total knee replacement.

Measurements of physical function after total knee arthroplasty (TKA) are uncertain and require investments for special equipment, space, and staff. Therefore, we evaluated the Short Physical Performance Battery (SPPB) 4 to 6 weeks preoperatively and 2 weeks following TKA as this test battery addresses lower extremity strength, coordination, and balance, without additional special investments. For context, we also employed the Six-Minute Walk test (6MWT) and peak torque knee extension. Our analysis consisted of three women and one man, with average ages of 68.3±3.9 years. Patients showed a decrease in all functional measurements: SPPB (mean change: -4.8±1.9, 44% decrease), 6MWT (-0.37±.21 m/s, 34% decrease), and peak torque (-11.8±8.8°/s, 68% decrease). Our findings suggest the SPPB is feasible and can be integrated easily in daily clinical practice.