Awake robotic lumbar decompression and fusion: A case report

Abstract

BACKGROUND

Lumbar degenerative disease affects nearly one-third of adults over 65 years old in the United States, a population expected to reach 89 million by 2050. Advances in minimally invasive spine surgery aim to address this growing demand by reducing blood loss, recovery time, and hospitalization. Robotic spine surgery improves hardware placement accuracy and reduces radiation exposure, while awake spine surgery performed under spinal anesthesia minimizes risks associated with general anesthesia and postoperative opioid use. However, reports describing the combined application of these techniques remain limited.

CASE SUMMARY

A 57-year-old male with hypertension presented with progressive neurogenic claudication and mechanical back pain refractory to conservative management. Magnetic resonance imaging demonstrated L4-L5 disc bulge with ligamentum flavum hypertrophy and central canal stenosis. After discussing operative options, the patient elected to undergo awake robotic-assisted L4-L5 decompression and fusion under spinal anesthesia. Preoperative thin-cut computed tomography was used for robotic trajectory planning. Intraoperatively, spinal anesthesia achieved adequate motor and sensory blockade, allowing prone positioning and robotic placement of cortical screws followed by decompression and fusion. The procedure was completed without complications, and postoperative imaging confirmed appropriate hardware placement. The patient recovered uneventfully and was discharged on postoperative day one.

CONCLUSION

Awake robotic lumbar decompression and fusion under spinal anesthesia is feasible and was completed without conversion to general anesthesia, supporting the combination of robotic precision with the recovery advantages of spinal anesthesia.

Key Words: Awake spine surgery; Spinal anesthesia; Robotic-assisted spine surgery; Cortical bone trajectory; Lumbar decompression and fusion; Enhanced recovery after surgery; Minimally invasive spine surgery; Case report

Core Tip: Minimally invasive spine surgery (MISS) provides several advantages, including reduced intraoperative blood loss, shorter recovery times, and decreased length of hospitalization. Cortical bone trajectory screws further enhance MISS by allowing a medial-to-lateral trajectory that reduces the need for extensive retraction, permits smaller incisions, and provides robust biomechanical fixation. Robotic spine surgery complements these techniques by offering enhanced intraoperative imaging and improved precision in hardware placement. Awake spine surgery performed under spinal anesthesia can be combined with robotic techniques to further shorten recovery and reduce postoperative pain.

INTRODUCTION

Lumbar degenerative disease affects nearly a third[1] of the 57.8 million individuals over 65 in the United States[2], a number projected to reach 89 million by 2050[3]. Advances in surgical technique will aid in providing surgical intervention for this growing population. Minimally invasive spine surgery (MISS) techniques reduce intraoperative blood loss, shorten recovery times, and decrease length of hospitalization. Robotic spine surgery represents a leading minimally invasive technology that provides advanced imaging, improving accuracy of hardware placement and reducing radiation exposure for both patients and surgical staff[4]. Awake spine surgery under spinal anesthesia, another technique that has recently gained traction, has been shown to limit the risks associated with general anesthesia, postoperative opioid consumption, and healthcare costs[5]. The use of spinal anesthesia provides sufficient motor and sensory blockade[6], and its use in spine surgery has been shown to decrease recovery times and minimize postoperative pain[7]. This paper aims to describe the technical aspects of awake robotic lumbar decompression and fusion under spinal anesthesia. This report describes our institution’s initial experience integrating awake spinal anesthesia with robotic-assisted instrumentation using cortical bone trajectory (CBT) screws.

CASE PRESENTATION

Chief complaints

A 57-year-old male presented with progressively worsening neurogenic claudication and mechanical back pain.

History of present illness

The patient reported that his symptoms had not improved despite medical management and six weeks of physical therapy.

History of past illness

His symptoms had been present for several months.

Personal and family history

His past medical history was notable for hypertension. No family history was reported.

Physical examination

Physical examination revealed 4/5 strength in right knee flexion and extension; strength was preserved in all other lower-extremity myotomes. Sensation was grossly intact, and lower-extremity deep tendon reflexes were symmetric without pathologic reflexes.

Laboratory examinations

Routine laboratory studies, including complete blood count, basic metabolic panel, and coagulation studies, were within normal limits.

Imaging examinations

MRI revealed an L4-L5 disc bulge, facet and ligamentum flavum hypertrophy, resulting in effacement of the bilateral subarticular recesses and central canal stenosis (Figure 1). Standing lumbar radiographs demonstrated no spondylolisthesis or segmental instability at L4-L5.

Figure 1 Preoperative magnetic resonance imaging demonstrating bilateral subarticular recess and central canal stenosis. A: Sagittal view; B: Axial view.

FINAL DIAGNOSIS

L4-L5 disc bulge with facet and ligamentum flavum hypertrophy resulting in bilateral subarticular recess effacement and central canal stenosis.

TREATMENT

Operative and non-operative options were explained to the patient who expressed the desire for surgical intervention due to continuing symptoms. The patient also voiced concerns about undergoing general anesthesia and, after being educated on the risks and benefits of awake vs general anesthesia, elected to undergo an awake L4-L5 decompression and fusion.

Preoperatively, a thin-cut lumbar spine computed tomography without contrast was obtained and uploaded into the Mazor X Stealth Edition navigation software (Figure 2) to estimate cortical screw size and trajectories (Figure 3). Once in the operating room, the anesthesiology team prepared for spinal anesthesia (Figure 4). The patient was placed in the sitting position and premedicated with midazolam and fentanyl. Anatomical landmarks were used to identify the L3-L4 level, and the procedural site was prepped and draped in the standard sterile fashion. An intradermal injection of 3 mL of 1% lidocaine provided local anesthesia. The spinal needle was inserted in the midline and slowly advanced until it entered the subarachnoid space, which was verified by removing the stylet and observing clear, free-flowing cerebrospinal fluid (Figure 4). Next, 1.6 mL of 0.75% hyperbaric bupivacaine combined with epinephrine 200 µg and fentanyl 20 µg was injected into the intraspinal space. Physical examination confirmed successful bilateral lower extremity motor blockade and a T7 sensory level.

Figure 2 Preoperative thin-cut computed tomography. A: Sagittal view; B: Axial view.

Figure 3 Preoperative hardware planning. A: Sagittal trajectory; B: Axial trajectory at L4; C: Anteroposterior view; D: Axial trajectory at L5.

Figure 4 Spinal anesthesia in the sitting position with the spinal needle at the L3-L4 level. The patient monitor in the background displays real-time vital signs, illustrating active awake intraoperative monitoring.

The patient was then placed on a Jackson frame in the prone position with appropriate pressure-point padding. The lumbar spine was then prepped and draped in a sterile fashion followed by marking of the surgical site with a marking pen (Figure 5). The robotic system was moved into the operative field on the right side of the patient (Figure 5). Alignment of the L4-L5 disc space was thereafter confirmed with X-ray. Then, a Schanz pin was placed into the right posterior superior iliac spine. A midline skin incision was made and further dissection with electrocautery was performed until the bilateral laminae and facet joints of L4 and L5 were exposed. To begin registration, the Schanz pin was connected to the bone-mount bridge on the robotic arm. The region of interest was defined by placing the navigation probe at the cranial and caudal boundaries of the incision. Once established, the three-dimensional marker of the robot effector arm was attached (Figure 6). Anteroposterior and oblique fluoroscopy images were obtained, ensuring both the marker and the spinal level of interest were visible (Figure 6). Anatomical landmarks served as reference points to confirm registration accuracy.

Figure 5 Patient preparation. A: Skin marking; B: Patient positioning and surgical site preparation.

Figure 6 Intraoperative registration. A: Three-dimensional marker; B: Lateral spinal-level confirmation; C: Anteroposterior spinal-level confirmation.

Registration accuracy was verified intraoperatively by manually probing planned trajectory entry points against the spinous process and lamina before drilling, and rechecked between screws to detect any cumulative drift; no clinically significant deviation was identified.

Throughout robotic docking and active screw placement, the surgical and anesthesia teams maintained continuous verbal communication with the patient. The patient was counseled to remain still and to alert the team prior to coughing or repositioning, and high-precision steps were performed during stable, controlled phases of respiration as confirmed by the anesthesia team.

Once registration was confirmed, the intraoperative images were segmented and labeled. Cortical screw entry points and trajectories were reviewed and adjusted as necessary. The robot’s effector arm was positioned at the first cortical screw target site, and a navigated dilator along with an outer cannula was advanced through the arm until bony contact was made. The dilator was then removed, leaving the outer cannula in place. A drill guide was inserted through the cannula and a navigated drill was advanced down the guide and pedicle until it reached a 30 mm positive stop (Figure 7). After removing both the drill and cannula, the cortical screw was tapped into the pedicle along its predetermined trajectory (Figure 7). The effector arm was then moved to the next screw trajectory and the remaining three cortical screws were placed in the same fashion. Cortical screws were used instead of traditional pedicle screws; the advantages conferred by cortical screws include a medial-to-lateral trajectory which minimizes the invasiveness of their placement, maximizes bone contact, and reduces neurovascular injury incidence[8]. Bilateral L4-L5 laminectomies, foraminotomies, facetectomies, and lateral recess decompressions were performed with bone curettes, Leksell, and Adson rongeurs. After decompression, two pre-bent rods were placed under fluoroscopic guidance to achieve reduction. Intraoperative X-rays were obtained to verify screw position and the wound was irrigated (Figure 8); no cerebrospinal fluid leak was identified. Postoperative X-rays confirmed proper placement of cortical screws and rods (Figure 8).

Figure 7 Surgical hardware placement. A: Drill guide; B: Cortical screw tapping.

Figure 8 Hardware placement radiographs. A: Intraoperative anteroposterior view; B: Intraoperative lateral view; C: Postoperative anteroposterior view; D: Postoperative lateral view.

OUTCOME AND FOLLOW-UP

The patient recovered well postoperatively and was discharged home on postoperative day one.

DISCUSSION

Awake spine surgery has been shown to reduce healthcare costs. This has been attributed to the speedier recovery and the shorter hospital length of stay[8]. Indications for awake spine surgery include surgeries involving a maximum of two vertebral levels, operations amenable to minimally invasive or endoscopic techniques, aging populations, and patients at higher risk of general anesthesia[9]. Poor surgical candidates for awake spine surgery include patients with a high risk of pulmonary complications, those with a high body mass index, obstructive sleep apnea, or a history of depression or anxiety[9]. Despite the benefits of awake spine surgery, some anesthesiology teams prefer that their patients receive general anesthesia[5]. In this report, the patient underwent an awake L4-L5 lumbar decompression and fusion under spinal anesthesia. In addition to providing intraoperative pain control, the motor blockade provided by spinal anesthesia functioned to limit patient movement[6], allowing for the placement of high-precision spinal hardware.

The benefits offered by robotic spine surgery have been described at length in the literature. Notable advantages include decreased radiation exposure, more accurate hardware placement, and decreased recovery times[10]. A few disadvantages of robotic systems include their slightly increased operative times and cost[11]. In a review of the history of robotic-assisted spine surgery, D'Souza et al[12] suggested that some of these limitations are present only during the initial learning curve. A review of robotic systems by Perfetti et al[13] ascribed the financial obstacle of robotic spine surgery to their initial acquisition. One study justified the initial investment by reporting significantly decreased postoperative infection and revision rates in robotic spine surgery[12]. The cost of acquiring these advanced systems may delay their widespread adoption, but the benefits conferred to patient recovery suggest that positive outcomes may offset the cost of acquisition[14].

Awake and robotic spine surgery have been widely implemented. When combined, they may offer a synergistic effect capable of further improving patient outcomes. Reported series of awake spine surgery and robotic-assisted lumbar instrumentation describe shorter hospital length of stay, lower postoperative opioid consumption, and high screw-placement accuracy when compared with traditional open and freehand minimally invasive approaches; published experience combining the two techniques remains limited, and the quantitative magnitude of any additive benefit will require further prospective study.

The medial-to-lateral, caudal-to-cranial trajectory of CBT screws permits a narrower exposure and less paraspinal muscle retraction than traditional pedicle-screw constructs. This reduction in soft-tissue stimulation is conceptually synergistic with awake spinal anesthesia, as it lessens nociceptive input that may otherwise challenge the duration of a single-shot spinal block.

Limitations of awake robotic spine surgery deserve explicit acknowledgment. Single-shot spinal anesthesia is time-limited, and patient discomfort, intraoperative movement, hemodynamic changes in the prone position, and constraints on emergent airway access must be anticipated. The workflow also requires a synchronized neurosurgery, anesthesiology, and operating-room nursing team, and carries a learning curve before efficiencies are realized; programs without prior awake or robotic spine experience should anticipate dedicated team training before adoption.

Although our patient was discharged on postoperative day one, the combination of awake spinal anesthesia, robotic-assisted instrumentation, and CBT fixation may support same-day discharge in appropriately selected patients in the future, which could partially offset the capital and per-case costs of robotic systems and contribute to value-based spine care.

Multidisciplinary collaboration will be required to further explore the benefits of these techniques. In conclusion, this report describes the details of an awake robotic spine surgery and speaks to its feasibility, while serving as an educational resource for healthcare providers.

CONCLUSION

MISS continues to advance with techniques that improve surgical precision while reducing perioperative morbidity. Robotic-assisted instrumentation enables accurate hardware placement, while CBT screws allow for smaller incisions and less tissue disruption. When combined with awake spine surgery under spinal anesthesia, these approaches may further shorten recovery time, reduce postoperative pain, and improve overall patient outcomes.