Mixed Reality in Spine Surgery: The Apple Vision Pro in Biportal Endoscopic Lumbar Fusion

Summary

This case report describes the first use of a mixed-reality head-mounted display during an endoscopic fusion procedure. The patient demonstrated meaningful clinical improvement following surgery, with complete resolution of leg pain and progressive improvement in back pain and functional status, sustained through the 7-month postoperative follow-up.

Abstract

The use of mixed reality (MR) in endoscopic spine surgery has recently been introduced, promising to enhance visualization, improve workflow, and support intraoperative decision-making. The successful use of the Apple Vision Pro (AVP) MR headset has recently been documented during biportal endoscopic spine surgery. To our knowledge, this case represents the first use of MR technology as an adjunct to biportal endoscopic spine fusion. An 81-year-old male with a history of lumbar stenosis and Grade 1 spondylolisthesis at level 4–5 presented with progressively worsening radicular pain refractory to conservative measures. Based on the clinical findings, the patient underwent a transforaminal lumbar interbody fusion (TLIF) via a biportal endoscopic approach. The procedure included endoscopic laminotomy, bilateral decompression, facetectomy, placement of an interbody cage with bone grafting, and posterior spinal instrumentation and fusion. Throughout the case, the operating surgeon wore the AVP MR Headset, which virtually displayed a live endoscopic view, over the real environment without obstructing the surgical field. The AVP consolidated the endoscopic feed directly into the surgeon's line of sight, eliminating the need to shift gaze between the operative field and external monitors and supporting a more ergonomic, streamlined operative workflow. The patient demonstrated complete resolution of radicular leg pain (VAS Leg 7 → 0) and marked functional recovery (ODI 14% → 2%) by two months postoperatively, with no intraoperative or postoperative complications, and these improvements were maintained through the seven-month follow-up. This case demonstrates the feasibility of using MR as an adjunct to biportal endoscopic lumbar fusion without observed complications. The AVP HMD provided an integrated, line-of-sight visualization platform that reduced reliance on external monitors and supported ergonomic surgical performance. Further investigation is needed to evaluate its effect on surgical efficiency and long-term patient outcomes.

Introduction

Biportal endoscopic spine surgery has been increasingly adopted as a minimally invasive alternative to conventional open approaches^1,2,3. With precise targeting and small-caliber instruments, biportal endoscopic spine surgery minimizes soft-tissue disruption while maximizing visualization^1,2. Additionally, the current literature has reported a potential reduction in postoperative analgesic use and intraoperative blood loss with endoscopy, suggesting a role for endoscopic techniques as a favorable option for outpatient spine procedures^4,5,6. However, the current endoscopic workflow requires the operating surgeon to reference multiple external monitors, including adjunct modalities such as fluoroscopy and intraoperative navigation systems, in addition to the operative field, creating potential ergonomic challenges. While endoscopic techniques often afford a more neutral head position compared to open surgery, ergonomic challenges in this setting are more commonly related to hand positioning, shoulder fatigue, and body posture. These cumulative demands contribute to increased musculoskeletal strain and cognitive burden.

Augmented reality (AR) overlays digital images onto the real environment, as seen through specialized glasses. Virtual reality (VR) places the user in a completely digital world through a headset that blocks out the real environment. Mixed reality (MR) integrates the real and digital environments, enabling users to interact simultaneously with virtual and real-world elements through an immersive headset.MR head-mounted displays (HMDs) can integrate endoscopic visualization directly into the surgeon’s field of view, thereby improving operative efficiency and reducing the surgeon’s ergonomic burden². MR is a novel technology that functions by superimposing digital information onto the real view of the physical world through wearable devices (such as HMDs) and incorporating environmental inputs such as the wearer's body position, spatial mapping, object recognition, and physical locations^7,8,9. All these functions combine to allow for rapid access to preoperative images and significant intraoperative image magnification that enables improved visualization^2,10. Multiple MR-based HMD devices have been reported in surgical applications, including the Microsoft HoloLens, and more recently, the Apple Vision Pro (AVP)^10,11,12,13. This case report aims to describe the use of the AVP HMD as an intraoperative adjunct during biportal endoscopic lumbar fusion surgery.

Case Presentation:
The patient was an 81-year-old male who presented with right buttock pain and associated right lower extremity radicular pain radiating to the lateral lower leg and dorsal foot. The patient described the pain as constant, with symptoms improving when lying down or sitting, but worsening when walking. Extended ambulation beyond the patient's established tolerance threshold precipitates symptom exacerbation within 24 h, reflecting a clinically significant limitation in functional mobility. There was no bowel or bladder dysfunction.

Diagnosis, Assessment, and Plan:
Prior nonoperative management included physical therapy, anti-inflammatory medications, and selective L4 and L5 nerve root blocks, which provided only partial and transient relief. After failure of conservative treatment, the patient elected to proceed with surgical intervention. Informed consent was obtained after discussion of the risks, benefits, and alternatives. The patient also provided consent for publication of clinical data and operative footage. Preoperative fluoroscopic imaging showed unstable Grade 1 anterolisthesis of L4 on L5 with mild dynamic instability, with associated multilevel degenerative changes, including disc space narrowing and facet arthropathy, consistent with degenerative spondylolisthesis and lumbar stenosis (Figure 1). Preoperative magnetic resonance imaging (MRI) illustrated multiple degenerative disc disease and facet arthropathy with moderate central canal stenosis, bilateral lateral recess stenosis, and a right-sided neuroforaminal narrowing at L4-L5 (Figure 2).

Protocol

1. MR Integration Workflow

1. The digital endoscopic video console output was connected to an NDI encoder using an HDMI cable.
2. The NDI encoder was connected to a dedicated Wi-Fi router via Ethernet cable, and the Wi-Fi router was connected to the AVP.
3. The Wi-Fi router settings were optimized to ensure a fast and reliable connection.
4. The HMD was placed on the surgeon's head, and the digital 4K video projection was set to the surgeon's field of view prior to scrubbing into the procedure.
5. Once the surgical portals were established, the endoscopic video feed was projected into the surgeon's field of view via the HMD. The MR HMD was worn throughout the procedure, and the virtual display was interacted with exclusively through mid-air hand gestures (Figure 3).
   NOTE: The estimated latency range measured by the NDI analysis system was 50–70 ms, which is imperceptible to the human eye, minimizing any lag during surgery. The digital 4K video projection can be placed in any position in space, and its size can be adjusted using hand gestures. Sterility is maintained throughout, as the Apple Vision Pro is controlled exclusively through mid-air hand gestures—such as tapping the index finger and thumb together, pinching and dragging, or swiping—that require no physical contact with any surface, device, or surgical field.

2. Surgical Procedure

1. Anesthesia and Patient Positioning
   1. The patient was identified and marked in the preoperative holding area.
   2. Following induction of general anesthesia, the patient was positioned prone on an OSI Jackson table with all bony prominences adequately padded.
   3. Prophylactic intravenous antibiotics and 1 g of tranexamic acid were administered prior to incision.
   4. Sequential compression devices were applied to both lower extremities for deep vein thrombosis prophylaxis throughout the procedure.
2. Preoperative Localization and Marking
   1. The skin was prepped and draped in the usual sterile fashion.
   2. Fluoroscopy was used to localize the operative level. The L4–5 level was confirmed fluoroscopically, and the midline and medial pedicle lines were marked. The planned incision sites were marked (Figure 3).
   3. Following skin and fascial incisions, sequential dilators were used to create a channel through the soft tissues.
   4. The adventitia (periosteal connective tissue layer) was bluntly dissected from the ipsilateral lamina using the soft tissue dissector. A semitubular retractor was placed through the working portal to maintain the outflow tract.
3. Endoscopic Procedure
   1. A 0° arthroscopic camera was introduced into the viewing portal.
   2. An L4–5 laminotomy was performed using a high-speed burr through the working portal, burring down to the level of the ligamentum flavum.
   3. The attachments of the ligamentum flavum were circumferentially released using Kerrisons and curved curettes. The ligamentum flavum was excised en bloc using a pituitary rongeur.
   4. The inferior and superior articular processes on the ipsilateral side were resected with an osteotome to perform the facetectomy. The bone from the facetectomy was harvested and processed for autograft.
   5. Kambin's triangle was identified, an annulotomy was performed, and superficial disc material was removed with an annular knife.
   6. The disc space was prepared using a combination of shavers, curettes, and pituitary rongeurs to remove disc material and the cartilaginous endplates.
   7. The autograft harvested from the facetectomy was packed into the disc space. The interbody cage was impacted into the disc space.
   8. Cage position was verified with fluoroscopy, and the cage was then expanded to its final configuration. The cage and disc space were backfilled with demineralized bone matrix allograft.
   9. Hemostasis was achieved using radiofrequency coagulation, absorbable hemostatic agents, and bone wax. The endoscopic camera and working channel were removed.
4. Percutaneous Instrumentation
   1. Fluoroscopy was used to localize the skin incisions. Skin and fascial incisions were made, and blunt dissection was carried down through the deep fascia to expose the facet joints and transverse processes.
   2. A Jamshidi needle was docked on the lateral wall of the left L4 pedicle. AP and lateral fluoroscopy were used to confirm the appropriate needle trajectory and positioning, and the needle was then advanced to the 25 mm mark (Figure 4).
   3. A guidewire was advanced into the vertebral body, and the Jamshidi needle was removed. The appropriately sized pedicle screw was measured and inserted. This process was repeated for the right L4 pedicle and the bilateral L5 screws.
   4. Appropriately sized rods were placed over the screw tulips, and the set screws were placed. The set screws were finally tightened.
   5. All guides were removed, and final AP and lateral fluoroscopic images were obtained to confirm satisfactory hardware positioning (Figure 5).
   6. The wounds were closed in a layered fashion, and a subfascial drain was placed.
      NOTE: The patient was extubated and transferred to the post-anesthesia care unit upon confirmation of stable condition. The estimated blood loss and intraoperative complications are documented.

3. Postoperative Care and Follow-Up

1. Postoperative pain was adequately controlled, and the surgical drain was removed prior to discharge. The patient was discharged on the day of surgery.
2. The patient was instructed to bear weight as tolerated and adhere to standard spinal precautions—avoiding deep spinal flexion, lifting greater than 10 lb, and excessive twisting—for 3 months postoperatively.
3. Routine clinical follow-up was scheduled at 2 weeks, 2 months, 6 months, and 1 year postoperatively.
4. At each follow-up visit, visual analog scale (VAS) scores for back and leg pain and the Oswestry Disability Index (ODI) were recorded to assess postoperative pain and functional outcomes.

Results

Clinical Outcomes
Immediately postoperatively, the patient reported a VAS back pain score of 6/10 and a VAS leg pain score of 0/10. Motor examination demonstrated 5/5 strength in all L2–S1 myotomes, with intact sensation throughout the bilateral L2–S1 dermatomal distributions.

At the 2-week follow-up, the patient reported improvement in back pain to 3/10, with leg pain remaining 0/10. The ODI score at this visit was 54%.

At the 2-month postopera...

Discussion

To our knowledge, this is the first reported case to demonstrate the feasibility of integrating the AVP HMD as an intraoperative adjunct in an endoscopic fusion surgery. The patient demonstrated early symptomatic improvement, with complete resolution of leg pain and improvement in back and functional status by 2 months after surgery, and will continue to be monitored longitudinally for changes in symptom trajectory. It is worth noting that the transient worsening of functional status observed at the two-week postoperativ...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
dualPortal Semitubular Cannula	Amplify Surgical
dualPortal Sequential Dilators	Amplify Surgical
dualPortal T-Handle	Amplify Surgical
DualX TLIF Cage Inserter	Amplify Surgical
DualX TLIF Expandable TLIF Cage	Amplify Surgical
DualX TLIF Locking Screw	Amplify Surgical
DualX Bone graft funnel and inserter	Amplify Surgical
dualPortal Kerrison rongeurs	Amplify Surgical
dualPortal Curved curettes	Amplify Surgical
dualPortal Pituitary ronguers	Amplify Surgical
dualPortal Nerve hook	Amplify Surgical
dualPortal Ball tipped probe	Amplify Surgical
dualPortal Penfield dissectors	Amplify Surgical
dualPortal Annular dissector	Amplify Surgical
dualPortal Scope retractor	Amplify Surgical
dualPortal Hemostatic agent applicator tip	Amplify Surgical
Arthroscope, 0 degree	Stryker
High speed burr, 3 mm diamond matchstick tip	Stryker
Shaver, 4 mm oval fluted bone cutting tip	Arthrex
Radiofrequency wand, 90 degree	Arthrex
Radiofrequency wand, 50 degree small tip	Arthrex
Irrigation pump tubing	Arthrex
Surgifoam	Ethicon
DBM fiber allograft	Seaspine
NDI analyses system
MR Integration hardware
OSI Jackson table
tranexamic acid