ISSLS PRIZE in basic science 2023: Lactate in lumbar discs-metabolic waste or energy biofuel? Insights from in vivo MRS and T2r analysis following exercise and nimodipine in healthy volunteers.

PURPOSE: To quantitatively assess the dynamic changes of Lactate in lumbar discs under different physiological conditions using MRS and T2r. METHODS: In step1, MRS and T2r sequences were standardized in 10 volunteers. Step2, analysed effects of high cellular demand. 66 discs of 20 volunteers with no back pain were evaluated pre-exercise (EX-0), immediately after targeted short-time low back exercises (EX-1) and 60 min after (EX-2). In Step 3, to study effects of high glucose and oxygen concentration, 50 lumbar discs in 10 volunteers were analysed before (D0) and after 10 days intake of the calcium channel blocker, nimodipine (D1). RESULTS: Lactate showed a distinctly different response to exercise in that Grade 1 discs with a significant decrease in EX-1 and a trend for normalization in Ex-2. In contrast, Pfirrmann grade 2 and 3 and discs above 40 years showed a higher lactate relative to proteoglycan in EX-0, an increase in lactate EX-1 and mild dip in Ex-2. Similarly, following nimodipine, grade 1 discs showed an increase in lactate which was absent in grade 2 and 3 discs. In contrast, exercise and Nimodipine had no significant change in T2r values and MRS spectrum of proteoglycan, N-acetyl aspartate, carbohydrate, choline, creatine, and glutathione across age groups and Pfirrmann grades. CONCLUSION: MRS documented changes in lactate response to cellular demand which suggested a 'Lactate Symbiotic metabolic Pathway'. The differences in lactate response preceded changes in Proteoglycan/hydration and thus could be a dynamic radiological biomarker of early degeneration.

Timing of intervention for spinal injury in patients with polytrauma.

OBJECTIVE: The optimal timing of surgical intervention of spinal fractures in patients with polytrauma is still controversial. In the setting of trauma to multiple organ systems, an inappropriately timed definitive spine surgery can lead to increased incidence of pulmonary complications, hemodynamic instability and potentially death, while delayed surgical stabilisation has its attendant problems of prolonged recumbency including deep vein thrombosis, organ-sp ecific infection and pressure sores. METHODS: A narrative review focussed at the epidemiology, demographics and principles of surgery for spinal trauma in poly-traumatised patients was performed. Pubmed search (1995-2020) based on the keywords - polytrauma OR multiple trauma AND spine fracture AND timing, present in "All the fields" of the search tab, was performed. Among 48 articles retrieved, 23 articles specific to the management of spinal fracture in polytrauma patients were reviewed. RESULTS: Spine trauma is noted in up to 30% of polytrauma patients. Unstable spinal fractures with or without spinal cord injury in polytrauma require surgical intervention and are treated based on the following principles - stabilizing the injured spine during resuscitation, acute management of life-and limb-threatening organ injuries, "damage control" internal stabilisation of unstable spinal injuries during the early acute phase and, definitive surgery at an appropriate window of opportunity. Early spine fracture fixation, especially in the setting of chest injury, reduces morbidity of pulmonary complications and duration of hospital stay. CONCLUSION: Recognition and stabilisation of spinal fractures during resuscitation of polytrauma is important. Early posterior spinal fixation of unstable fractures, described as damage control spine surgery, is preferred while a delayed definitive 360° decompression is performed once the systemic milieu is optimal, if mandated for biomechanical and neurological indications.

An analysis of the safety and efficacy of dexmedetomidine in posterior spinal fusion surgery for adolescent idiopathic scoliosis: a prospective randomized study.

PURPOSE: To evaluate whether use of dexmedetomidine, a centrally acting α2 adrenergic agonist, reduces opioid consumption in PSF. METHODS: Adolescent idiopathic scoliosis patients who underwent PSF were randomized into morphine (M) and dexmedetomidine (D) group. M group received a 10 µg/kg/h IV infusion of morphine for 24 h post-surgery, while the D group received a 0.4 µg/kg/h IV infusion of dexmedetomidine. Trained nursing staffs recorded hourly vital parameters (blood pressure, pulse rate, respiratory rate, and oxygen saturation). Pain, postoperative nausea/vomiting (PONV), and sedation were rated using: the numerical rating scale (NRS), the PONV scale, and sedation status scale (SS). Preemptive analgesia with gabapentin and postoperative analgesia with ketorolac and paracetamol were used in both the groups. Any complications in the study groups were recorded. RESULTS: No significant difference was noted between the groups (M vs D) with respect to NRS (3.1 ± 0.8 vs 2.7 ± 0.5) (p = 0.07) and breakthrough analgesia requirements (0.78 vs 0.45) (p = 0.17). A significant difference was noted between the groups with respect to the secondary outcome measures of time to ambulation (56.6 ± 12.7 h vs 45.2 ± 7.7 h), time to oral analgesics (84.3 ± 20 h vs 64.0 ± 15.4 h), and time to liquid intake (8.3 ± 1.3 h vs 7.2 ± 1.2 h). The M group had a higher PONV score (0.46 ± 0.3 vs 0.16 ± 0.1) (p < 0.001) and mean time to bowel opening (112.7 ± 28.4 h vs 90.1 ± 20.5 h) (p < 0.001). Additionally, the enema or suppository requirements for bowel opening were significantly more (0.59 ± 0.6 vs 0.26 ± 0.4) (p = 0.01) in the M group. CONCLUSION: Dexmedetomidine provided analgesia comparable to morphine with lower PONV scores. It also reduced the opioid requirements in the PSF patients without additional complications and can therefore be incorporated in pain management protocols.