This case demonstrates that combining SA, ESPB, and magnesium sulfate is safe and provides adequate analgesia following spine surgery in a high-risk patient.
Postoperative pain after spine surgery can hinder recovery and quality of life. Given the rising prevalence of spine pathologies requiring surgery it is important to address postoperative pain to avoid complications such as transition to chronic pain and reduced mobility. This can place a significant economic burden on healthcare systems and individuals due to the costs of medical care, lost productivity, and disability [4, 8, 9].
Pathophysiologically postoperative pain after spine surgery is nociceptive, neuropathic, and inflammatory responses linked to the number of levels operated on [10]. Patients typically report severe pain within the initial 12 hours after surgery, which intensifies during movement due to muscle contraction triggered by wound related pain due to length of the surgical incision, damage to the surrounding tissue, and position pressure after surgery [4, 10]. Over the following 48–72 hours back pain remains significant particularly during movement. Delayed movement raises the risk of complications like pneumonia, deep vein thrombosis, and emotional stress, therefore, necessitating efficient analgesia [10].
Regional anesthesia (RA) also referred to as neuro-axial anesthesia is primarily achieved through epidural or spinal anesthesia [11]. RA presents several advantages to general anesthesia (GA), including minimized systemic effects, lower risk of deep venous thrombosis, pulmonary embolism, myocardial infarction, renal failure, and better hemodynamic stability making it an attractive choice for patients not eligible for GA [11]. While GA remains the favored choice of anesthesia in spine surgery, there is a growing trend in utilizing SA, which has demonstrated comparable safety and efficacy to GA [11]. RA yields prolonged analgesic effects leading to faster recovery and discharge [6]. But certain limitation such as lack of a secure airway, interreference with intraoperative neurophysiologic monitoring (IONM), and risk of neurological complications have hindered its wider application and confined it to certain cases [11].
Epidural anesthesia provides analgesia during and after spine surgery. It was once considered the gold standard for postoperative analgesia but the procedure’s technical complexities, potential complications, and its interference with early motor function evaluation have reduced its appeal [9, 11].
the erector spinae plane block (ESPB) is another regional anesthesia technique that entails injecting local anesthetics between the erector spinae muscles and the transverse processes of the vertebra [1]. The exact mechanism of ESPB is unknown but it is hypothesized to operate by blocking the dorsal and ventral rami of the thoracic and lumbar spinal nerves [6].
ESPB has found application across diverse surgical contexts owing to its simplicity, safety and efficacy [1, 2, 4, 8, 12]. ESPB has been used along with GA to provide postoperative pain relief in spine surgery [13]. While some studies have reported ESPB as the main anesthesia for hip and anorectal surgery with using remifentanil and propofol respectively [12, 14] there is currently no report of its application as the main anesthesia in spine surgery.
The utilization of ultrasound guidance further simplifies this procedure. To perform the ESPB, the patient is placed in a lateral, prone or sitting position. An ultrasound probe is placed longitudinally 3–4 cm lateral to the spinous process at the desired level of block, and the erector spinae muscle and the transverse process are visualized. A needle is then inserted in-plane with the ultrasound guide and advanced in a cephalad or caudal direction until the tip lies in the erector spinae plane [1, 4]. Administrating ESPB at the vertebral level corresponding to the incision is preferred over a fixed vertebral level [13].
ESPB is considered safe because the injection target is distant from critical structures such as blood vessels, pleura, or spinal cord. No serious complication such as drug toxicity, nerve injury, or pneumothorax have been reported in association with this technique [13].
ESPB reduced the opioid consumption within the first 24 hours post-surgery and resulted in lower pain levels and complications such as postoperative nausea and vomiting (PONV) compared to patients who didn’t receive the block. PONV is even reported to be more distressing and less tolerated than the postoperative pain, contributing to extended hospital stays [13]. Our patient did not experience any PONV. Collectively previous studies have regarded ESPB as a promising technique providing effective analgesia, reducing opioid requirements, improving pain control, enhancing recovery and patient satisfaction [4, 6, 9, 11, 13].
Given our patient’s medical history it was crucial to tailor an anesthesia plan to avoid potential respiratory complications and provide sufficient analgesia to ensure optimal outcomes. Patients with systemic sclerosis must go careful preoperative assessment to determine the extent of organ involvement and systemic manifestations of the disease. SS is a complex autoimmune disease and its manifestations can occur in the skin, musculoskeletal system, cardiovascular system, nervous system, eyes, lungs, kidneys, and gastrointestinal tract [15]. Skin involvement such as dermal thickening reduce mandible motility and mouth opening. This can make intubation challenging in severe cases. Respiratory manifestations of SS are the main cause of morbidity and mortality and therefore the main intraoperative implication for anesthesia. Our patient had pulmonary artery hypertension and interstitial lung fibrosis resulting in arterial hypoxia and decreased pulmonary compliance. Also, opioid consumption must be minimized due to the increased sensitivity to its respiratory suppression. The choice of anesthetic drugs is also important to avoid cardiac complications like arrhythmia. Our patient did not show any sign of dysrhythmia before or during surgery. Assessing the renal function which can also be affected by SS is also important to adjust drug dosing. Our patient had normal kidney function. Additionally, manifestations like Reynaud phenomenon, esophageal dysmotility and neuropathy can influence anesthesia. Hypothermia induced vasoconstriction can cause Reynaud phenomenon, making patients susceptible to temperature changes. This can be managed with maintaining proper room temperature, active warming, and IV fluids. Conditions like gastroesophageal reflux disease (GERD) are prevalent in SS patients, increasing the risk of aspiration during anesthesia and further respiratory complications. Therefore, therapy with proton pump inhibitors (PPI) or H2-receptor blockers must be started before surgery. Also, medication, especially immunosuppressants, should be reviewed for potential interactions.
Combining ESPB with spinal anesthesia in SS patients enhances the analgesic efficacy, reduces opioid consumption, and avoids the systemic effects associated with GA while providing hemodynamic stability and lower risks of cardiac complication ensuring a smoother recovery. But it might pose technical challenges due to skin and joint changes. The choice of local anesthetic, concentration, and volume are important in this technique.
The analgesic effect of ESPB lasts from 4 to 72 hours [6]. To further enhance the analgesia the patient received IV infusion of magnesium sulfate throughout the surgery. Intraoperative magnesium sulfate can improve postoperative pulmonary function and analgesia through several mechanisms: acting as an N-methyl-D-aspartate (NMDA) receptor antagonist, reducing pain transmission and excitability in the central nervous system; anti-inflammatory properties, decreasing inflammation at the surgical site; stabilizing nerve cell membranes and reducing excessive pain signaling through modulating neurotransmitters; reducing opioid tolerance and opioid sparing effects, lowering opioid doses and minimizing opioid-related side effects; and reducing neuromuscular transition through inhibition of neuronal calcium influx [15]. Moreover, calcium influx inhibition in smooth muscles results in bronchodilation and vasodilation in arterioles and coronary arteries. The muscle-relaxing effect of magnesium further enhances the efficacy of the surgical procedure. Magnesium also possesses antiarrhythmic effects and is useful for tachyarrhythmia associated with bupivacaine, reducing cardiovascular complications [15].
Postoperatively the patient had no pain and did not demand analgesia for 12 hours. In the next hours, analgesia was achieved with fixed-time intervals of intravenous acetaminophen, oxycodone, and gabapentin. diclofenac was given as rescue analgesia on days 2 and 3 post-surgery.
The described multimodal approach resulted in an uneventful perioperative course for the patient. Effective analgesia was achieved, minimizing the need for opioids and reducing the risk of respiratory complications. The combination of SA, ESPB, and magnesium sulfate infusion holds promise for improving perioperative outcomes in similar patients. However, further research is warranted to establish the safety and efficacy of this approach, including a larger patient cohort and comparison with other analgesic techniques.