Pushing the Limits of Minimally Invasive Spine Surgery-From Preoperative to Intraoperative to Postoperative Management.

The introduction of minimally invasive surgery ushered in a new era of spine surgery by minimizing the undue iatrogenic injury, recovery time, and blood loss, among other complications, of traditional open procedures. Over time, technological advancements have further refined the care of the operative minimally invasive spine patient. Moreover, pre-, and postoperative care have also undergone significant change by way of artificial intelligence risk stratification, advanced imaging for surgical planning and patient selection, postoperative recovery pathways, and digital health solutions. Despite these advancements, challenges persist necessitating ongoing research and collaboration to further optimize patient care in minimally invasive spine surgery.

Awake Spinal Fusion Is Associated with Reduced Length of Stay, Opioid Use, and Time to Ambulation Compared to General Anesthesia: A Matched Cohort Study.

OBJECTIVE: There is increasing interest in performing awake spinal fusion under spinal anesthesia (SA). Evidence supporting SA has been positive, albeit limited. The authors set out to investigate the effects of SA versus general anesthesia (GA) for spinal fusion procedures on length of stay (LOS), opioid use, time to ambulation (TTA), and procedure duration. METHODS: The authors performed a retrospective review of a single surgeon's patients who underwent lumbar fusions under SA versus GA from June of 2020 to June of 2022. SA patients were compared to demographically matched GA counterparts undergoing comparable procedures. Analyzed outcomes include operative time, opioid usage in morphine milligram equivalents, TTA, and LOS. RESULTS: Ten SA patients were matched to 10 GA counterparts. The cohort had a mean age of 66.77, a mean body mass index of 27.73 kg/m2, and a median American Society of Anesthesiologists Physical Status Score of 3.00. LOS was lower in SA versus GA patients (12.87 vs. 50.79 hours, P = 0.001). Opioid utilization was reduced in SA versus GA patients (10.76 vs. 31.43 morphine milligram equivalents, P = 0.006). TTA was reduced in SA versus GA patients (7.22 vs. 29.87 hours, P = 0.022). Procedure duration was not significantly reduced in SA patients compared to GA patients (139.3 vs. 188.2 minutes, P = 0.089). CONCLUSIONS: These preliminary retrospective results suggest the use of SA rather than GA for lumbar fusions is associated with reduced hospital LOS, reduced opioid utilization, and reduced TTA. Future randomized prospective studies are warranted to determine if SA usage truly leads to these beneficial outcomes.

Awake spinal anesthesia facilitates spine surgery in poor surgical candidates: A case series.

BACKGROUND: Annually, hundreds of thousands of patients undergo surgery for degenerative spine disease (DSD). This represents only a fraction of patients that present for surgical consideration. Procedures are often avoided due to comorbidities that make patients poor candidates for general anesthesia (GA) and its associated risks. With increasing interest in awake surgery under spinal anesthesia (SA), the authors have observed that SA may facilitate spine surgery in patients with relative contraindications to GA. With this in mind, the authors set out to summarize the outcomes of a series of highly comorbid patients who received surgery under SA. METHODS: Case logs of a single surgeon were reviewed, and patients undergoing spine surgery under SA were identified. Within this group, patients were identified with relative contraindications to GA, such as advanced age and medical comorbidities. For these patients, for whom surgery was facilitated by SA, the medical records were consulted to report demographic information and patient outcomes. RESULTS: Ten highly comorbid patients were identified who received lumbar spine surgery for DSD under SA. Comorbidities included octogenarian status, obesity, and chronic health conditions such as heart disease. The cohort had a mean age of 75.5 and a mean American Society of Anesthesiologists Physical Status (ASA-PS) score of 3.1. The patients were predicted to have a 2.74-fold increase of serious complications compared to the average patient. There were no adverse events. CONCLUSION: For patients with symptomatic, refractory DSD and relative contraindications to GA, SA may facilitate safe surgical intervention with excellent outcomes.

Interscalene block with liposomal bupivacaine versus continuous interscalene catheter in primary total shoulder arthroplasty.

BACKGROUND: Multimodal pain regimens in total shoulder arthroplasty (TSA) now include regional anesthetic techniques. Historically, regional anesthesia for extended postoperative pain control in TSA was administered using a continuous interscalene catheter (CIC). Liposomal bupivacaine (LB) is used for its potential for similar pain control and fewer complications compared with indwelling catheters. We evaluated the efficacy of interscalene LB compared with a CIC in postoperative pain control for patients undergoing TSA. METHODS: This was a retrospective cohort study at a tertiary-care academic medical center including consecutive patients undergoing primary anatomic or reverse TSA from 2016 to 2020 who received either single-shot LB or a CIC for perioperative pain control. Perioperative and outcome variables were collected. The primary outcome was postoperative pain control, whereas the secondary outcome was health care utilization. RESULTS: The study included 565 patients, with 242 in the CIC cohort and 323 in the LB cohort. Demographic characteristics including sex (P = .99) and race (P = .81) were similar between the cohorts. The LB cohort had significantly lower mean pain scores at 24 hours (3 vs. 2, P < .001) and 36 hours (3 vs. 2, P < .001) postoperatively. The CIC cohort showed a higher percentage of patients experiencing a pain score of 9 or 10 postoperatively (29% vs. 17%, P = .001), whereas the LB cohort had a significantly greater proportion of opioid-free patients (32% vs. 10%, P < .001). Additionally, a greater proportion of CIC patients required opioid escalation to patient-controlled analgesia (7% vs. 2%, P = .002). The CIC cohort experienced a greater length of stay (2.3 days vs. 2.1 days, P = .01) and more 30-day emergency department visits (5% vs. 2%, P = .038). CONCLUSIONS: LB demonstrated lower mean pain scores at 24 and 36 hours postoperatively and lower rates of severe postoperative pain. Additionally, LB patients showed significantly higher rates of opioid-free pain regimens. These results suggest that as part of a multimodal pain regimen in primary shoulder arthroplasty, LB may provide greater reductions in pain and opioid use when compared with CICs.

Postoperative changes in cognition and cerebrospinal fluid neurodegenerative disease biomarkers.

OBJECTIVE: Numerous investigators have theorized that postoperative changes in Alzheimer's disease neuropathology may underlie postoperative neurocognitive disorders. Thus, we determined the relationship between postoperative changes in cognition and cerebrospinal (CSF) tau, p-tau-181p, or Aß levels after non-cardiac, non-neurologic surgery in older adults. METHODS: Participants underwent cognitive testing before and 6 weeks after surgery, and lumbar punctures before, 24 h after, and 6 weeks after surgery. Cognitive scores were combined via factor analysis into an overall cognitive index. In total, 110 patients returned for 6-week postoperative testing and were included in the analysis. RESULTS: There was no significant change from before to 24 h or 6 weeks following surgery in CSF tau (median [median absolute deviation] change before to 24 h: 0.00 [4.36] pg/mL, p = 0.853; change before to 6 weeks: -1.21 [3.98] pg/mL, p = 0.827). There were also no significant changes in CSF p-tau-181p or Aß over this period. There was no change in cognitive index (mean [95% CI] 0.040 [-0.018, 0.098], p = 0.175) from before to 6 weeks after surgery, although there were postoperative declines in verbal memory (-0.346 [-0.523, -0.170], p = 0.003) and improvements in executive function (0.394, [0.310, 0.479], p < 0.001). There were no significant correlations between preoperative to 6-week postoperative changes in cognition and CSF tau, p-tau-181p, or Aß42 changes over this interval (p > 0.05 for each). INTERPRETATION: Neurocognitive changes after non-cardiac, non-neurologic surgery in the majority of cognitively healthy, community-dwelling older adults are unlikely to be related to postoperative changes in AD neuropathology (as assessed by CSF Aß, tau or p-tau-181p levels or the p-tau-181p/Aß or tau/Aß ratios). TRIAL REGISTRATION: clinicaltrials.gov (NCT01993836).

Ultrasound-guided genicular nerve blocks following total knee arthroplasty: a randomized, double-blind, placebo-controlled trial.

INTRODUCTION: Local anesthetic blockade of the genicular nerves, known targets of radiofrequency ablative techniques for knee pain, has not previously been studied in a randomized controlled trial evaluating acute pain after knee arthroplasty. We hypothesized that genicular nerve blockade added to an existing block regimen in total knee arthroplasty would result in a reduction in 24 hours opioid consumption. METHODS: Patients (American Society of Anesthesiologists 1-3, aged 18-85 years) undergoing primary total knee arthroplasty were randomized to receive single-injection nerve blocks of the superolateral, superomedial, and inferomedial genicular nerves with injectate (15 mL 0.25% bupivacaine and 2 mg dexamethasone or 15 mL saline placebo). All subjects received a standard oral analgesic regimen, spinal anesthetic with 12.5 mg isobaric bupivacaine, infiltration between the popliteal artery and capsule of the knee with 0.2% ropivacaine, and postoperative adductor canal perineural infusion with 0.2% ropivacaine. The primary outcome was 24 hours opioid consumption (measured in morphine milliequivalents). RESULTS: Forty (40) subjects were enrolled. Opioid consumption at 24 hours was significantly lower in the BLOCK group compared with the SHAM group (23±20 vs 58±35, p<0.001), and this difference remained significant at 48 hours (50±40 vs 98±56, p=0.004). Pain scores were reduced in the BLOCK group at time 6 hours (2.6±1.9 vs 4.3±2.2, p=0.012), but were otherwise similar at remaining time points. Patient satisfaction at 24 hours and 20 m walk test times were similar between groups. DISCUSSION: Genicular nerve blockade was associated with a reduction in opioid consumption at 24 hours in primary total knee arthroplasty patients. TRIAL REGISTRATION NUMBER: NCT03706313.

Femoral artery block (FAB) attenuates thigh tourniquet-induced hypertension: a prospective randomized, double-blind, placebo-controlled trial.

INTRODUCTION: Prolonged tourniquet inflation during surgery frequently leads to tourniquet hypertension (TH), which is thought to arise from compression of A-δ fibers leading to sympathetically mediated C fiber activation. In the lower extremity, C fibers and other sympathetic nerve fibers are carried along the femoral artery. We hypothesized that blockade of these fibers at the femoral artery would decrease the incidence of TH. METHODS: Thirty American Society of Anesthesia 1-3 patients aged 18-75 undergoing total ankle arthroplasty were randomized to receive 15 mL of injectate (mepivacaine 1.5% or saline placebo) at the anteromedial aspect of the common femoral artery at the level of the inguinal crease under ultrasound guidance. Both groups received preoperative popliteal sciatic and saphenous nerve blocks for analgesia and a standardized general anesthetic. Esmolol was administered if systolic blood pressure rose >30% above baseline. Incidence of TH was the primary outcome. RESULTS: TH was present in 93.3% of sham patients versus 33.3% of block patients. Mean systolic pressure at 120 min and 150 min of tourniquet time was significantly higher in the sham group compared with the block group. Esmolol requirement (95.3+107.6 v 8.0+14.2, p=<0.001) was also significantly higher in the sham group. No differences were noted in pain scores or opioid consumption, and no patient experienced sensory or motor block of the femoral nerve. DISCUSSION: Under these experimental conditions, injection of local anesthetic around the femoral artery reduced the incidence of TH and intraoperative esmolol requirement. TRIAL REGISTRATION NUMBER: www.clinicaltrials.gov (NCT03390426; December 28, 2017).

The relative analgesic value of a femoral nerve block versus adductor canal block following total knee arthroplasty: a randomized, controlled, double-blinded study.

BACKGROUND: Multiple comparative studies report that adductor canal blocks provide similar pain relief to femoral nerve blocks following total knee arthroplasty. However, adductor canal blockade fails to anesthetize several important femoral nerve branches that contribute to knee innervation. We sought to clarify this anatomic discrepancy by performing both blocks in sequence, using patients as their own controls. We hypothesized that patients would experience additional pain relief following a superimposed femoral nerve block, demonstrating that these techniques are not equivalent. METHODS: Sixteen patients received continuous adductor canal block before undergoing knee arthroplasty under general anesthesia. In the recovery room, patients reported their pain score on a numeric scale of 0-10. Once a patient reached a score of five or greater, he/she was randomized to receive an additional femoral nerve block using 2% chloroprocaine or saline sham, and pain scores recorded every 5 min for 30 min. Patients received opioid rescue as needed. Anesthesiologists performing and assessing block efficacy were blinded to group allocation. RESULTS: Patients randomized to chloroprocaine versus saline reported significantly improved median pain scores 30 min after the femoral block (2.0 vs. 5.5, P = 0.0001). Patients receiving chloroprocaine also required significantly fewer morphine equivalents during the 30 min post-femoral block (1.0 vs. 4.5 mg, P = 0.03). CONCLUSIONS: Adductor canal block is a useful technique for postoperative pain following total knee arthroplasty, but it does not provide equivalent analgesic efficacy to femoral nerve block. Future studies comparing efficacy between various block sites along the thigh are warranted.

A protocol to reduce self-reported pain scores and adverse events following lumbar punctures in older adults.

OBJECTIVE: Lumbar punctures (LPs) are important for obtaining CSF in neurology studies but are associated with adverse events and feared by many patients. We determined adverse event rates and pain scores in patients prospectively enrolled in two cohort studies who underwent LPs using a standardized protocol and 25 g needle. METHODS: Eight hundred and nine LPs performed in 262 patients age ≥ 60 years in the MADCO-PC and INTUIT studies were analyzed. Medical records were monitored for LP-related adverse events, and patients were queried about subjective complaints. We analyzed adverse event rates, including headaches and pain scores. RESULTS: There were 22 adverse events among 809 LPs performed, a rate of 2.72% (95% CI 1.71-4.09%). Patient hospital stay did not increase due to adverse events. Four patients (0.49%) developed a post-lumbar puncture headache (PLPH). Twelve patients (1.48%) developed nausea, vasovagal responses, or headaches that did not meet PLPH criteria. Six patients (0.74%) reported lower back pain at the LP site not associated with muscular weakness or paresthesia. The median pain score was 1 [0, 3]; the mode was 0 out of 10. CONCLUSIONS: The LP protocol described herein may reduce adverse event rates and improve patient comfort in future studies.

THE EFFECTS OF PERIOPERATIVE DEXAMETHASONE ON GLYCEMIC CONTROL AND POSTOPERATIVE OUTCOMES.

Objective: Perioperative glucocorticoids are commonly given to reduce pain and nausea in patients undergoing surgery. However, the glycemic effects of steroids and the potential effects on morbidity and mortality have not been systematically evaluated. This study investigated the association between perioperative dexamethasone and postoperative blood glucose, hospital length of stay (LOS), readmission rates, and 90-day survival. Methods: Data from 4,800 consecutive orthopedic surgery patients who underwent surgery between 2000 and 2016 within a single health system were analyzed retrospectively. Results: Patients with and without diabetes mellitus (DM) who were given a single dose of dexamethasone had higher rates of hyperglycemia during the first 24 hours after surgery as compared to those who did not receive dexamethasone (hazard ratio [HR] was 1.81, and 95% confidence interval [CI] was [1.46, 2.24] for the DM cohort; HR 2.34, 95% CI [1.66, 3.29] for the nonDM cohort). LOS was nearly 1 day shorter in patients who received dexamethasone (geometric mean ratio [GMR] 0.79, 95% CI [0.75, 0.83] for patients with DM; GMR 0.75, 95% CI [0.72, 0.79] for patients without DM), and there was no difference in 90-day readmission rates. In patients without DM, dexamethasone was associated with a higher 90-day overall survival (99.07% versus 96.90%; P = .004). Conclusion: In patients with and without DM who undergo orthopedic surgery, perioperative dexamethasone was associated with a transiently higher risk of hyperglycemia. However, dexamethasone treatment was associated with a shorter LOS in patients with and without DM, and a higher overall 90-day survival rate in patients without DM, compared to patients who did not receive dexamethasone. Abbreviations: BMI = body mass index; CAD = coronary artery disease; CI = confidence interval; DM = diabetes mellitus; GMR = geometric mean ratio; HR = hazard ratio; IV = intravenous; LOS = length of stay; POD = postoperative day.

Continuous adductor canal blockade facilitates increased home discharge and decreased opioid consumption after total knee arthroplasty.

BACKGROUND: There is a growing interest in avoiding discharging patients to rehab to maximize outcome and minimize complications after total knee arthroplasty (TKA). In addition, use of postoperative pain pathways that minimize opioid use is critical amidst the current opioid epidemic. However, the ideal pain regimen after TKA has yet to be determined. METHODS: From July 1, 2013 to October 1, 2014 two perioperative pathways were used to address surgical pain. These included either a single shot femoral nerve block plus liposomal bupivacaine pericapsular injection (FNB + LB-PAI) or adductor canal catheter plus posterior capsule single shot block (ACC + iPACK), each with an oral analgesic protocol. Little modification occurred with regard to surgical technique, postoperative medications, or postoperative physical therapy (PT). RESULTS: Overall, 264 unilateral, primary TKA patients (146 FNB + LB-PAI, 118 ACC + iPACK) were included. ACC + iPACK patients had a shorter median length of stay (LOS, 2.0 vs 3.0, p < 0.001), more discharges home (79.7% vs 67.8%, p = 0.002), and less median opioid consumption (IV morphine equivalents, IVME, 20.0 vs 44.1, p < 0.001) than the FNB + LB-PAI group. In multivariable analysis, use of ACC + iPACK remained independently associated with shorter LOS, increased discharge home, and less IVME consumed when controlling for confounding variables. ACC + iPACK patients also had fewer opioid related adverse events (0.8 vs 5.5, p = 0.045) and a lower rate of MUA (0.8% vs 6.2%, p = 0.026). CONCLUSIONS: We recommend ACC + iPACK with a multimodal oral analgesic protocol as the primary postoperative analgesia in enhanced recovery TKA protocols. This resulted in an easier recovery with fewer complications. LEVEL OF EVIDENCE: Level III.

Pectoral Fascial (PECS) I and II Blocks as Rescue Analgesia in a Patient Undergoing Minimally Invasive Cardiac Surgery.

INTRODUCTION: Patients undergoing minimally invasive cardiac surgery have the potential for significant pain from the thoracotomy site. We report the successful use of pectoral nerve block types I and II (Pecs I and II) as rescue analgesia in a patient undergoing minimally invasive mitral valve repair. CASE REPORT: In this case, a 78-year-old man, with no history of chronic pain, underwent mitral valve repair via right anterior thoracotomy for severe mitral regurgitation. After extubation, he complained of 10/10 pain at the incision site that was minimally responsive to intravenous opioids. He required supplemental oxygen because of poor pulmonary mechanics, with shallow breathing and splinting due to pain, and subsequent intensive care unit readmission. Ultrasound-guided Pecs I and II blocks were performed on the right side with 30 mL of 0.2% ropivacaine with 1:400,000 epinephrine. The blocks resulted in near-complete chest wall analgesia and improved pulmonary mechanics for approximately 24 hours. After the single-injection blocks regressed, a second set of blocks was performed with 266 mg of liposomal bupivacaine mixed with bupivacaine. This second set of blocks provided extended analgesia for an additional 48 hours. The patient was weaned rapidly from supplemental oxygen after the blocks because of improved analgesia. CONCLUSIONS: Pectoral nerve blocks have been described in the setting of breast surgery to provide chest wall analgesia. We report the first successful use of Pecs blocks to provide effective chest wall analgesia for a patient undergoing minimally invasive cardiac surgery with thoracotomy. We believe that these blocks may provide an important nonopioid option for the management of pain during recovery from minimally invasive cardiac surgery.

Ultrasound-Guided Suprainguinal Fascia Iliaca Technique Provides Benefit as an Analgesic Adjunct for Patients Undergoing Total Hip Arthroplasty.

Analgesia after total hip arthroplasty is often accomplished by the fascia iliaca compartment block, traditionally performed below the inguinal ligament, to anesthetize both femoral and lateral femoral cutaneous nerves. The course of the lateral femoral cutaneous nerve below the inguinal ligament is variable as opposed to consistent above the inguinal ligament in the pelvis. In this case series including 5 patients, we demonstrate that an ultrasound-guided suprainguinal fascia iliaca approach would consistently anesthetize the lateral femoral cutaneous nerve along with anterior cutaneous femoral nerve branches and provide cutaneous analgesia after total hip arthroplasty, as shown by decreased opioid consumption.

Schizophrenia-like GABAergic gene expression deficits in cerebellar Golgi cells from rats chronically exposed to low-dose phencyclidine.

One of the most consistent findings in schizophrenia is the decreased expression of the GABA synthesizing enzymes GAD(67) and GAD(65) in specific interneuron populations. This dysfunction is observed in distributed brain regions including the prefrontal cortex, hippocampus, and cerebellum. In an effort to understand the mechanisms for this GABA deficit, we investigated the effect of the N-methyl-D-aspartate receptor (NMDAR) antagonist phencyclidine (PCP), which elicits schizophrenia-like symptoms in both humans and animal models, in a chronic, low-dose exposure paradigm. Adult rats were given PCP at a dose of 2.58 mg/kg/day i.p. for a month, after which levels of various GABAergic cell mRNAs and other neuromodulators were examined in the cerebellum by qRT-PCR. Administration of PCP decreased the expression of GAD(67), GAD(65), and the presynaptic GABA transporter GAT-1, and increased GABA(A) receptor subunits similar to those seen in patients with schizophrenia. Additionally, we found that the mRNA levels of two Golgi cell selective NMDAR subunits, NR2B and NR2D, were decreased in PCP-treated rats. Furthermore, we localized the deficits in GAD(67) expression solely to these interneurons. Slice electrophysiological studies showed that spontaneous firing of Golgi cells was reduced by acute exposure to low-dose PCP, suggesting that these neurons are particularly vulnerable to NMDA receptor antagonism. In conclusion, our results demonstrate that chronic exposure to low levels of PCP in rats mimics the GABAergic alterations reported in the cerebellum of patients with schizophrenia (Bullock et al., 2008. Am. J. Psychiatry 165, 1594-1603), further supporting the validity of this animal model.

Altered expression of genes involved in GABAergic transmission and neuromodulation of granule cell activity in the cerebellum of schizophrenia patients.

OBJECTIVE: Deficits in gamma-aminobutyric acid (GABA) signaling have been described in the prefrontal cortex, limbic system, and cerebellum in individuals with schizophrenia. The purpose of the present study was to further investigate cerebellar gene expression alterations as they relate to decreases in GABAergic transmission by examining the expression of GABAergic markers, N-methyl-d-aspartic-acid (NMDA) receptor subunits, and cerebellum neuromodulators in individuals with schizophrenia. METHOD: Subjects were postmortem men with a diagnosis of schizophrenia (N=13) and a postmortem interval-matched non-psychiatric male comparison group (N=13). The authors utilized real-time-quantitative polymerase chain reaction (PCR) to measure mRNA levels of the following GABAergic markers: glutamic acid decarboxylase (GAD) 65 and 67; GABA plasma membrane transporter-1 (GAT-1); GABA type A (GABA(A)) receptor subunits alpha(6), beta(3), and delta; and parvalbumin. In addition, real-time-quantitative PCR was utilized to assess mRNA levels of the NMDA receptor (NR) subunits NR1, NR2-A, NR2-B, NR2-C, and NR2-D as well as the cerebellar neuromodulators glutamate receptor (GluR)-6, kainate-preferring glutamate receptor subunit-2 (KA2), metabotropic glutamate receptor (mGluR)-2 and mGluR3, and neuronal nitric oxide synthase. Measurements for mRNA levels were determined using lateral cerebellar hemisphere tissue from both schizophrenia and comparison subjects. RESULTS: Schizophrenia subjects showed significant decreases in mRNA levels of GAD(67), GAD(65), GAT-1, mGluR2, and neuronal nitric oxide synthase. Increases in GABA(A)-alpha(6 )and GABA(A)-delta as well as GluR6 and KA2 were also observed. Medication effects on the expression of the same genes were examined in rats treated with either haloperidol (Sprague-Dawley rats [N=16]) or clozapine (Long-Evans rats [N=20]). Both haloperidol and clozapine increased the levels of GAD(67) in the cerebellum and altered the expression of other cerebellar mRNAs. CONCLUSIONS: These findings suggest that GABA transmission is decreased in the cerebellar cortices in individuals with schizophrenia and additional gene expression changes may reflect an attempt to increase GABA neurotransmission at the cerebellar glomerulus.