The Aurora ZIP® Interspinous Device system is a posterior, non-pedicle fixation and fusion device used in the thoracolumbar and lumbosacral spine (T1–S1) for spinal fusion surgery.
It is primarily designed as a minimally invasive alternative to traditional pedicle screws and rods for stabilizing unstable spinal segments.
How it works: Rather than requiring screws anchored through the pedicles into the vertebral body, the ZIP device is inserted between adjacent spinous processes (the bony ridges felt along the center of the back). It features two clamping side plates that ratchet together, gripping the spinous process bone to stabilize the motion segment.
Graft chamber: The core barrel includes a dedicated window packed with bone graft material to facilitate solid bony fusion across the interspinous space.
Indications: Degenerative disc disease, spondylolisthesis (grade 1), lumbar spinal stenosis, and supplemental fixation alongside interbody cages.
Procedural advantages: Typically performed on an outpatient basis through a single small incision, involving minimal blood loss, minimal muscle disruption, and faster recovery than open lumbar fusion.
A spinal fusion treats pain by welding one vertebra to the next and eliminating movement. New-Generation ADR treats pain by restoring natural height and providing controlled movement for a healthy lifestyle.
How does Disc Replacement Work?
Artificial Disc Replacement (ADR) is sometimes called Total Disc Replacement (TDR). In this surgical procedure, the damaged spinal disc in the neck or lower back is completely removed and replaced with an artificial disc, restoring healthy height and movement. This procedure is commonly performed via the anterior approach, through the abdominal cavity, and sometimes through the lateral approach. This is less traumatic for the patient compared to the posterior approach (through the back), which is how many spinal fusions are performed.
ADR was pioneered in Germany in the 1980’s. Since then many new models of ADR implant have been developed, becoming more advanced as new materials and technologies become available. For suitable candidates, ADR surgery can offer everything a fusion can, such as decompression of nerves, restoration of healthy height, and at the same time ALSO restore natural controlled mobility. This is especially important for younger patients in their 20’s, 30’s and 40’s, active patients who enjoy sports and outdoor activities, or anyone wanting to enjoy a healthy lifestyle without restriction to their spine mobility.
ADR can also be offered at the levels next to a previous fusion, if the fusion has caused new damage. This is superior to an extension of the fusion, because it best mitigates post-fusion adjacent segment disease, which is the transfer of stress to other parts of the spine.
Latest Artificial Disc Replacement (ADR) Technologies
Our top specialists are experienced with multiple ADR implant models for use in the Cervical and Lumbar spine, including the most innovative and the most studied devices worldwide. Advanced disc implants are designed to replicate the movement of a natural disc, and newer generation devices offer 6 degrees of movement, including vertical compression, with resistance increasing towards the end of every motion. This helps protect the facet joints and allows for safer multi-level use in suitable patients.
Combining the expertise of one of the world’s most experienced Orthopedic Spine Surgeons and an experienced Neurosurgeon ensures that all the options available worldwide are considered.
Our extensive experience with Spinal Fusion Surgery, Artificial Disc Replacement, Multi level hybrid Fusion-ADR and less invasive microdiscectomy and laminectomy surgery is critical to ensuring the correct treatment is chosen for each spinal level requiring attention.
Dr. Ritter-lang has more experience with disc replacement surgery than most US surgeons
Yes, Dr. Karsten Ritter-Lang has substantially more artificial disc replacement (ADR) experience than the vast majority of U.S. spine surgeons. In fact, his procedural case volume places him in an upper tier that very few spine surgeons worldwide, especially in the United States, come close to matching.
The disparity between his experience and that of a typical U.S. spine surgeon comes down to several factors:
Dr. Ritter-Lang: Has performed more than 8,000 artificial disc replacements (lumbar and cervical combined) over nearly three decades.
Average U.S. Spine Surgeon: In the U.S., total disc replacement—particularly in the lumbar spine—remains a niche procedure compared to spinal fusion. A typical U.S. spine surgeon may perform only a handful of cervical disc replacements per year and fewer than five (or often zero) lumbar disc replacements annually. Even top-tier, high-volume U.S. motion-preservation specialists rarely exceed 1,000 to 2,000 total career ADR cases.
Modern artificial disc technology, such as the Charité and ProDisc, was developed, refined, and routinely implanted across Europe starting in the late 1980s and 1990s. Dr. Ritter-Lang trained under early pioneers at the Charité clinic in Berlin during this period, giving him a multi-decade head start.
United States: The FDA did not approve the first lumbar artificial disc (Charité) until late 2004, and the first cervical disc (PRESTIGE ST) until 2007. This delayed U.S. adoption by nearly 15 years, meaning American surgeons simply did not have the regulatory access to perform these procedures during the formative decades of modern disc arthroplasty.
In the United States, private insurance policies historically placed heavy restrictions or outright non-coverage determinations on lumbar disc replacement, classifying it as “investigational” far longer than European systems. As a result, U.S. surgeons overwhelmingly default to spinal fusions (such as ALIF, TLIF, or posterior instrumentation) rather than disc replacement.
Multi-Level Restrictions: The FDA has maintained strict limits on multi-level lumbar disc replacement, generally approving devices for single-level usage (with limited two-level approvals). In contrast, Dr. Ritter-Lang and other European pioneers have routinely performed multi-level lumbar and hybrid procedures for decades.
Lumbar disc replacement requires an anterior retroperitoneal approach, operating past major vascular structures (the aorta, vena cava, and iliac vessels).
In the United States, spine surgeons rarely perform their own vascular access; they almost universally employ a separate “access surgeon” (a general or vascular surgeon) to open and close the surgical corridor.
Having started in trauma and orthopedic reconstructive surgery in Germany, Ritter-Lang performs high-volume anterior exposures directly, accumulating an uncommon degree of familiarity with anterior column access and vessel mobilization.
While the U.S. has respected pioneers who champion motion preservation, Dr. Ritter-Lang’s career volume of 8,000+ disc replacements places him well ahead of all global practitioners.
Some are specialists in multi-level cervical and lumbar arthroplasty, but in terms of overall career years, pioneering background, and absolute disc replacement volume, Dr. Karsten Ritter-Lang remains the more experienced spine surgeon.
Dr. Karsten Ritter-Lang a top orthopedic spine surgeon, explains how this occurs. Fuse one level, and when the level next to it wears down, that needs surgery as well, and the cycle continues. This is how you end up in a spinal fusion cascade. This is one reason motion-preserving options matter so much. The goal isn’t exclusively to fix the level causing pain today. It’s to hopefully avoid turning one treated level into several surgeries.
If you’re dealing with chronic leg and/or back pain and considering spine surgery, it’s worth asking whether a motion-preserving option is available to you from the start, and if fusion is the recommendation, why that’s the case. If you’ve already had a spine procedure and you’re facing a second surgery, the question becomes whether that next level could be treated in a way that preserves mobility and function.
Patients Seek Artificial Disc Replacement in Germany
International patients frequently travel to specialized spine centers in Germany to access advanced motion-preserving spine surgery alternatives to conventional spinal fusion.
Key clinical differentiators include:
- Multi-Level Approaches: Routine performance of multi-level lumbar (L4-L5, L5-S1) and cervical disc arthroplasty.
- Prosthetic Technology: Access to next-generation viscoelastic and unconstrained disc prosthetics (e.g., M6-L, M6-C, ProDisc-L, LP-ESP, activL).
- Anterior Retroperitoneal Exposure: Muscle-sparing anterior lumbar approaches designed to preserve posterior musculature and reduce adjacent segment disease (ASD).
About Dr. Karsten Ritter-Lang: Motion Preservation & Spine Arthroplasty
Dr. Karsten Ritter-Lang is recognized internationally for his clinical focus on intervertebral disc prosthetics and complex spinal reconstruction.
- Surgical Experience: Over 30 years dedicated to motion-preserving spinal procedures, having performed thousands of cervical and lumbar artificial disc replacements.
- Academic Lineage: Trained directly under Prof. Dr. Kurt Schellnack and Dr. Karin Büttner-Janz at the Charité University Hospital in Berlin—the pioneering research team that developed the original Charité artificial disc prosthesis.
- Clinical Focus: Multi-level lumbar disc replacement, motion-preserving reconstruction for degenerative disc disease, and alternatives to spinal fusion.
Remote Consultations & International MRI Reviews
For patients seeking preliminary assessments or second opinions regarding total disc replacement and spinal stenosis treatments:
- Better Disc Replacement: Detailed comparative guides on motion preservation vs. spinal fusion, clinical indications for lumbar total disc replacement (TDR), and multi-level case analyses.
BetterDiscReplacement
- Stenum Hospital International Patient Portal: Preliminary remote MRI evaluations, international intake protocols, and surgical technology overviews for European and overseas patients
Stenum Hospital
Medically Reviewed By
Dr. med. Karsten Ritter-Lang M.D.
Diploma of medicine (Institut of Immunology Charité)
1988 – 1991
Doctorade of medicine (Institut of Immunology Charité)
Senior consultant of spinal surgery in two hospitals (DRK Berlin Westend and Stenum Hospital) and private practice in Potsdam,ENDOCERT Certified awarded the title and certification of Specialist for Trauma Surgery (Facharzt für Unfallchirurgie) in 2009