Anaesthetic Management of Robotic Assisted Spine Surgeries - A Single Centre Experience of Consecutive Cases

Introduction**:**

In recent years, there has been a growing emphasis on developing surgical techniques to expedite the recovery process following spine surgery. [1,2,3,4] Robotic-assisted surgeries have significantly improved the safety and precision of spine procedures, enabling earlier mobilization and shorter hospital stays. [5]

 The year 2020 marked the introduction of Robotic-Assisted Spine Surgery in India. Our centre, among the first five to adopt this technology, employs the complete combination of MazorX Stealth Edition (Medtronic Limited, Dublin, Ireland), O-arm, and the radiolucent Allen® Advance operating table for conducting Robotic Spine Surgeries. The Allen Advance table, designed for complex spine procedures, facilitates safe patient positioning through a 360-degree rotation from supine to prone and vice versa. While various studies explore robotic spine surgery from a surgeon’s perspective, limited attention has been given to the experience and challenges faced by anaesthesiologists.

 Since there hasn’t been any prospective studies done with respect to the anaesthetic experience in a robotic spine surgery , our primary objective will be to evaluate Induction to Incision time, changes in airway pressure with positioning, the correlation between Body Mass Index (BMI) and airway pressures, blood loss, total intraoperative opioid requirements, and postoperative pain scores. Secondary objectives will include assessing the duration of surgery, time to mobilization, and length of hospital stay. Based on our initial experience, we plan to propose a workflow for smooth anaesthesia conduct during robotic spine surgeries, focusing on the unique features of the Allen table.

Type of Study –Randomised controlled trial

Aims & objectives:

AIM: To determine the anaesthetic experience and challenges faced in conducting anaesthesia for robotic assisted spine surgeries.OBJECTIVE:

Our primary goal is to evaluate specific endpoints such as induction-to-incision time, changes in airway pressure, the correlation between body mass index (BMI) and airway pressures, blood loss, total intraoperative opioid usage, and postoperative pain scores.

Secondary goals to assess the duration of surgery, time to mobilisation, and length of hospital stay. In our study, the induction-to-incision time was chosen as the parameter to reflect the anaesthesiologist’s learning curve , while blood loss and duration of surgery were chosen to reflect the surgeon’s learning curve. We will also assess Quality of recovery, Satisfaction scores.

JUSTIFICATION FOR STUDY: Spinal decompression and fusion surgeries are commonly done surgical procedures for degenerative disc disease. Advances in technology have enabled percutaneous placement of pedicle screws with the help of specialized robots. This leads to lower blood loss and minimal disruption of paraspinal muscles, which allows for early mobilization and shorter hospitalization. This study aims to determine the clinical outcomes of patients undergoing robotic assisted spine surgery.

 Review of Literature:

1.     Debono B et al, in their retrospective analysis of prospectively gathered data of all patients who underwent spinal fusion for degenerative conditions selected two 2-year periods, the first from before any implementation of ERAS principles (pre-ERAS years 2012–2013) and the second corresponding to a period when the paradigm was applied widely (post-ERAS years 2016–2017). The pre-ERAS group (2012–2013) included 1563 patients (159 ALIF, 749 ACDF, and 655 posterior fusion), and the post-ERAS group (2016–2017) included 1920 patients (202 ALIF, 612 ACDF, and 1106 posterior fusion).At their centre they had a 24-hour unit which was dedicated to the support of ERAS care, where the surgeon , anaesthesiologist, physical therapist and ERAS nurse all perform their duties in educating the patient about the procedure prior to the surgery. The patient then registered online for hospital admission and was admitted on the day of surgery at 7am to fast track the process.  Eating was allowed until 6 hours prior to surgery, and clear liquids were permitted even up to 2 hours before, especially carbohydrate supplementation (e.g., apple juice). The surgeon usually performed a minimally invasive procedure, the use of drains was drastically limited, and the daily use of braces, lumbar belts, or soft/rigid cervical collars was not promoted except in exceptional cases. The patient typically spent 2 hours in the recovery room and received early advice from the rehabilitation team.  Early discharge was conducted after validation by the operator according to a checklist. Concerning pain control, the opioid-sparing multimodal approach was adopted by immediately favouring tramadol and nonsteroidal anti-inflammatory drugs in the recovery room. Oxycodone was provided if pain was poorly controlled by these other agents. Patient education was focused on the use of analgesics, with particular emphasis on avoiding the use of an opioid analgesic. Regarding the early home follow up, a nurse from the ERAS team was available 24 hours a day by phone or a dedicated mobile application (app). A surgical consultation was routinely undertaken at 6 weeks postoperatively, during which neurological and pain statuses were recorded. They found that the mean LOS was significantly shorter in the post ERAS group than in the pre-ERAS group for all three conditions. At the end of the mobile app monitoring period (15 days), an online survey was offered; 808 responses could be analyzed , Concerning the satisfaction with overall care, 699 patients (86.5%) were satisfied or very satisfied. As regards the stay preparation, 750 patients (92.8%) were satisfied or very satisfied. Regarding the organization of discharge, 671 (83.0%) were satisfied or very satisfied.7

2.     Sofffin EM et al conducted a retrospective cohort study of prospectively collected data. They assessed the pathway compliance , Length of Stay in hospital(LOS), incidence and types of complications for LOS exceeding 23 hours and prevalence of opioid tolerance. The pathway was applied to all consecutive patients undergoing minimally invasive lumbar microdiscectomy (34) or minimally invasive lumbar decompression (laminectomy or laminotomy; 27) between April and November 2017 cared for by a single surgeon at a single institution. They included all patients, without any selection or exclusion criteria. The majority (91%) were cared for by a single anesthesiologist. Where individual patient factors precluded a particular intervention (e.g., allergy to or refusal of a pathway component), the intervention was withheld. They had a specific ERAS team who took part in the process at every step , from counselling of patient preoperatively till discharge and follow up. Standard NPO guidelines were followed. In the holding area on the day of surgery, acetaminophen (1000 mg), gabapentin (300 mg), and antiemetic prophylaxis (scopolamine, 1.5 mg, transdermal) according to risk factors for postoperative nausea and vomiting were all given. Intraoperatively, a total intravenous anesthesia (TIVA) technique was preferentially used, based on propofol (50– 100mg/kg/min) and ketamine (0.1–0.5 mg/min). Up to 0.5 minimal alveolar concentration (MAC) of inhaled agents (either isoflurane or sevoflurane) were permitted to achieve desired depth of anesthesia. Euvolemia and normothermia maintained. Additional nonopioid analgesia (ketorolac 15–30 mg; lidocaine 1–2 mg/kg/h) and dual antiemetic prophylactic therapy (ondansetron, 4 mg and dexamethasone, 4–8 mg) were administered intravenously. The same surgeon performed all surgeries using minimally invasive techniques. Tramadol was available for rescue analgesia in the postanesthesia care unit (PACU). If pain was poorly controlled, the patient was assessed by the anesthesiologist, and oxycodone was provided, if indicated. Patients were discharged with a prescription for a short course of tramadol. Numerical Rating Scale(NRS) scores were recorded at regular intervals during the PACU stay. The first score was taken after recovery from anaesthesia, and then at 30-minute intervals until the NRS was 4 on two successive occasions. Thereafter, NRS scores were recorded hourly for the duration of the PACU admission, or if the patient reported worsening pain (i.e., NRS > 5). NRS scores were additionally recorded for any patients with severe pain (NRS > 8) for whom opioid therapy was escalated from tramadol to oxycodone. In the immediate post op there was cessation of intravenous fluid administration, restarting oral intake, and mobilization within 2 hours of PACU arrival. Discharge required stable vital signs, an alert and oriented mental state, controlled pain (NRS < 4), adequate social support and ability to self-care after discharge, and agreement by the patient they were ready for discharge.6

3.     Staartjes VE et al, in their study analysed data from their institutional registry of all patients who underwent elective spine surgery between November 2013 to October 2018, for whom an ERAS protocol was adopted. A total of 2592 consecutive patients were included in the primary efficacy analysis . Of these, 2117 (82%) completed at least 1 PROM(Patient Reported Outcome Measures) invitation. The types of surgeries included were lumbar disc herniation, spinal stenosis, spondylolisthesis, facet cysts, or proven degenerative disc disease (DDD), with a minimum follow-up of 30 days to assess readmissions. Preoperatively patients were advised to stop smoking and alcohol consumption at least 3 months before being considered for surgical treatment. They were educated about the three principles of conduct (“Three Golden Rules”) during the recovery process, namely: 1) You are allowed to do anything you want, but 2) you must listen to your body carefully, and 3) you must stop what you are doing when you experience too much pain. They  were asked to cease working and work-related activities at home for the first 3 postoperative weeks, not to drive a car within 3 weeks of surgery and were instructed not to undergo physical therapy during the first 3 months. Patients would have a scheduled telephone call 2 days and 14 days after surgery to check on their status. Only fusion patients had a scheduled early 6-week clinical and radiological follow-up. Patients underwent Minimally invasive (MI) tubular microdiscectomy, single-level robot-guided MI posterior lumbar interbody fusion (PLIF) or transforaminal lumbar interbody fusion (TLIF), mini-open anterior lumbar interbody fusion(ALIF), or mini-open decompression. Antibiotic and Anti thrombotic prophylaxis was given preoperatively. For local analgesia, 2.5 mg/ml of ropivacaine was intramuscularly administered prior to incision. General anaesthesia was maintained using propofol and a short-acting opioid (sufentanil). The use of muscle relaxants was limited to allow for faster recovery. Fluid imbalance was minimized, vasopressors were administered to regulate blood pressure, and autologous cell-salvage transfusion was available during all procedures. Surgical site drains were used only for mini-open decompression and MI-PLIF and were removed as soon as possible. Urinary catheters were removed early. Postoperatively, opioid-sparing analgesia was maintained and adjusted as appropriate using nonsteroidal anti-inflammatory drugs (NSAIDs) and paracetamol. We considered using patient-controlled analgesia with intravenous piritramide and long-acting opioids only for patients with unmanageable pain after fusion procedures. Whenever feasible, patients were mobilized 2 hours after surgery under guidance of a physical therapist and were discharged home after a minimum stay of 1 night, as soon as the following conditions were true: 1) pain controlled by oral analgesics, 2) no complication (e.g., incidental durotomy) that would require prolonged hospital stay, and 3) ability to climb stairs and to perform ADL. Fusion patients were provided with a light elastic brace. Before the first visit, all patients received an invitation to complete an online baseline questionnaire on a validated Web-based application , which was assessed again at 6 weeks, 12 months, and 24 months . They found that the proportion of patients who were discharged the morning after surgery was significantly high. Based on this change, their Department of Finance estimated a reduction in nursing costs of 46.8%. Adverse events demonstrated a decreasing trend. From the 6-week to the 1-year follow-up there was significant further improvement of functional impairment ( Oswestry Disability Index [ODI]) and in health-related quality of life in terms of EQ-5D index and EQ-VAS (visual analog scale).8

4.     Angus M et al, in their institute applied their ERAS protocol to all patients undergoing elective adult deformity correction with a posterior instrumented fusion of greater than one level of fusion form 2012. The results have been collated over a 2-year period(Post ERAS) and compared to the 3 years prior(Pre ERAS) to the implementation of the ERAS service. Preoperatively , thorough and focused counselling of patients by a Multi Disciplinary Team was conducted. A comprehensive analgesic regimen was employed perioperatively. There was routine use of intraoperative lignocaine infusions for analgesia, along with use of pre-incision ketamine boluses and post op ketamine infusions. The use of these medications intra operatively avoided the use of anaesthetic agents with long recovery/half-life and therefore allowed for early mobilisation post operatively. Multimodal post op analgesia regimes with PCA opioids/ketamine and IV paracetamol were used. Early drain removal, thromboprophylaxis, wound care, bowel regime, analgesia expectations and mobilisation were followed. Post discharge patient received call at day one and three post discharge and then clinic review at 6 days. They found that Patient satisfaction, measured using the Core Outcome Measures Index (COMI-back) score (which has been validated for use in spinal degenerative surgery) had shown an improvement since the implementation of the ERAS service, with 100% of patients post ERAS satisfied post-operatively compared to 84% prior to the service. Average Length of Stay and 30 day readmission rate was also reduced in Post ERAS group.9

 5.    D’Astorg H et al , in their retrospective analysis collected data of all patients who had undergone spine surgery between January 2017 and January 2018. The following surgeries were included : herniated lumbar disc treatment; single or multilevel lumbar stenosis treatment; single or 2-level anterior retroperitoneal lumbar interbody fusion (ALIF); single to 3-level circumferential fusion using a combined approach (ALIF associated with posterior instrumentation); single to 3-level posterior fusion; anterior cervical fusion. In the preoperative period thorough MDT counselling of patient was carried out. Multimodal Anaesthesia(dexamethasone, ketamine, few morphine derivatives, local anaesthetics, anti-emetics) was given. The smallest number of catheters, urinary catheters and drains were inserted as possible and these were removed as early as possible. After surgery, the patients were given oral analgesia. The patient was encouraged to get out of bed as early as possible. Discharge on the same day was approved, or not, by the surgeon based on pain control, early mobilisation and the ability to climb a flight of stairs. The patients were phoned by the coordinating nurse on day +1 after leaving hospital.The postoperative surgical consultation took place 4–6 weeks after surgery . At the final follow-up (1 year for arthrodesis and 3 months for microdiscectomy) patients had access to a final satisfaction questionnaire. 386 patients were included in this study(193 in each group). A significant difference was observed for both groups in the VAS scores for cervical, lumbar and radicular pain pre and post-surgery. A significant difference was observed for both groups in the ODI(Oswestry Disability Index) scores pre- and post-surgery. There was a significant difference in mean LOS( defined as the average number of days spent in hospital) , between the two groups (ERAS group, mean LOS = 2.6 days ,control group mean LOS = 4.4 days]. 10

 Departments involved : Department of Spine Anaesthesiology, Manipal Hospital, Old airport Road.

Study Design: A prospective double blinded randomized control study.

Study period : Following ethics committee  approval study will be conducted for a duration of 12 months

Sample size : Consecutive patients who underwent robotic assisted spine surgeries will be included in the study.Materials and methods:

a)    Inclusion and exclusion criteria:

 INCLUSION CRITERIA:

1. Adult patients aged between 18 and 65 years of either sex.

2. ASA I and ASA II undergoing general anesthesia for elective Robotic Spine surgery.

EXCLUSION CRITERIA:

1. Patient refusal.

Body mass index ≥ 35 kg/ m2

3. Patients with cardiac, coronary, renal, hepatic, cerebral diseases and peripheral vascular diseases.

4. Patients coming for emergency surgeries.

5. Pregnancy.

Inability to use VAS (Visual Analogue Scale).

 All consecutive patients posted for robotic lumbar fusion surgery between 1st December 2024 to 1st December 2025 will be included in the study. The data will be analyzed in a blinded fashion. Quantitative variables will be expressed as mean± standard deviation and qualitative data will be expressed as percentages. The interclass correlation coefficient and kappa coefficient will be used to determine inter and intra observer variability. The chi-squared test will be used to compare the frequencies and independent sample t-test will be used to compare means. The statistical analysis will then be done using SPSS for windows version 21.

Permission from the ethics committee and the departmental scientific committee will be taken before initiating any step of the project.

          9. Potential risks and benefits: RISK: None. BENEFITS:  The study will help us in preparing an anaestesia protocol for all our patients who are scheduled to undergo robotic spine surgery and thereby help in regularizing patient care and improving patient safety.