AI/MLSaMDIVD (In Vitro Diagnostic)TherapeuticDiagnosticis PCCP AuthorizedThirdpartyExpeditedreview
Intended Use

The aprevo® anterior and lateral lumbar interbody fusion devices are intended for interbody fusion in skeletally mature patients and are to be used with supplemental fixation instrumentation cleared for use in the lumbar spine. The aprevo® anterior and lateral lumbar interbody fusion devices are indicated for use as an adjunct to fusion at one or more levels of the lumbar spine in patients having an ODI >40 and diagnosed with severe symptomatic adult spinal deformity (ASD) conditions. These patients should have had six months of non-operative treatment. The devices are intended to be used with autograft and/or allogenic bone graft comprised of cancellous and/or cortico-cancellous bone graft. These implants may be implanted via a variety of open or minimally invasive approaches. These approaches may include anterior lumbar interbody fusion or lateral lumbar interbody fusion.

The aprevo® anterior and lateral lumbar interbody fusion devices are indicated for use at one or more levels of the lumbosacral spine as an adjunct to fusion in patients with the following indications: degenerative disc disease (DDD), disc herniation (with myelopathy and/or radiculopathy), spondylolisthesis, deformity (degenerative scoliosis or kyphosis), spinal stenosis, and failed previous fusion (pseudarthrosis). DDD is defined as discogenic back pain with degeneration of the disc as confirmed by history and radiographic studies. These patients should be skeletally mature and have had at least six (6) months of non-operative treatment. aprevo® anterior and lateral lumbar interbody fusion devices are to be filled with autograft bone and/or allogenic bone graft composed of cancellous and/or corticocancellous bone. These devices are intended to be used with supplemental fixation systems that have been cleared for use in the thoracolumbosacral spine (e.g., posterior pedicle screw and rod systems). These implants may be implanted via a variety of open or minimally invasive approaches.

The aprevo® transforaminal lumbar interbody fusion device is intended for interbody fusion in skeletally mature patients and is to be used with supplemental fixation instrumentation cleared for use in the lumbar spine. The aprevo® transforaminal lumbar interbody fusion device is indicated for use as an adjunct to fusion at one or more levels of the lumbar spine in patients having an ODI >40 and diagnosed with severe symptomatic adult spinal deformity (ASD) conditions. These patients should have had six months of non-operative treatment. The device is intended to be used with autograft and/or allogenic bone graft comprised of cancellous and/or cortico-cancellous bone graft. These implants may be implanted via a variety of open or minimally invasive approaches.

The aprevo® transforaminal lumbar interbody fusion device is indicated for use at one or more levels of the lumbosacral spine as an adjunct to fusion in patients with the following indications: degenerative disc disease (DDD), disc herniation (with myelopathy and/or radiculopathy), spondylolisthesis, deformity (degenerative scoliosis or kyphosis), spinal stenosis, and failed previous fusion (pseudarthrosis). DDD is defined as discogenic back pain with degeneration of the disc as confirmed by history and radiographic studies. These patients should be skeletally mature and have had at least six (6) months of non-operative treatment. aprevo® transforaminal lumbar interbody fusion devices are to be filled with auto graft bone and/or allogenic bone graft composed of cancellous and/or corticocancellous bone. These devices are intended to be used with supplemental fixation systems that have been cleared for use in the thoracolumbosacral spine (e.g., posterior pedicle screw and rod systems). These implants may be implanted via a variety of open or minimally invasive approaches.

The aprevo® anterior lumbar interbody fusion device with interfixation (ALIF-X) is intended for interbody fusion in skeletally mature patients. The aprevo® anterior lumbar interbody fusion device with interfixation (ALIF-X) is indicated for use as an adjunct to fusion at one or more levels of the lumbar spine in patients having an ODI >40 and diagnosed with severe symptomatic adult spinal deformity (ASD) conditions. These patients should have had six months of non-operative treatment. The device is intended to be used with autograft and/or allogenic bone graft comprised of cancellous bone and/or corticocancellous bone and is to be used with supplemental fixation cleared for use in the lumbar spine. The device may be implanted via an open or minimally invasive approach.

The aprevo® anterior lumbar interbody fusion device with interfixation (ALIF-X) is indicated for use at one or more levels of the lumbosacral spine as an adjunct to fusion in patients with the following indications: degenerative disc disease (DDD), disc herniation (with myelopathy and/or radiculopathy), spondylolisthesis, deformity (degenerative scoliosis, kyphosis, or sagittal), spinal stenosis, and failed previous fusion (pseudarthrosis). DDD is defined as discogenic back pain with degeneration of the disc as confirmed by history and radiographic studies. The aprevo® anterior lumbar interbody fusion device with interfixation (ALIF-X) is intended for standalone use at one or two levels of the spine when used with the screws that accompany the implant and with implants less than or equal to 20° of lordosis. At more than two levels or with implants greater than 20° of lordosis, the aprevo® anterior lumbar interbody fusion device with interfixation (ALIF-X) is intended to be used with the screws that accompany the implant and with supplemental fixation. When used at more than one level in patients with degenerative scoliosis and/or sagittal deformity, the aprevo® anterior lumbar interbody fusion device with interfixation (ALIF-X) must be used with the screws that accompany the implant and with supplemental internal spinal fixation system (e.g., pedicle screw system) cleared by the FDA for use in the lumbar spine. These patients should be skeletally mature and have had at least six months of non-operative treatment. The device is to be filled with autograft bone and/or allogenic bone graft comprised of cancellous and/or corticocancellous bone. The device may be implanted via an open or minimally invasive approach.

The aprevo® TLIF-C Articulating System is intended for interbody fusion in skeletally mature patients and is to be used with supplemental fixation instrumentation cleared for use in the lumbar spine. The aprevo® TLIF-C Articulating System is indicated for use as an adjunct to fusion at one or more levels of the lumbar spine in patients having an ODI >40 and diagnosed with severe symptomatic adult spinal deformity (ASD) conditions. These patients should have had six months of non-operative treatment. The device is intended to be used with autograft and/or allogenic bone graft comprised of cancellous and/or cortico-cancellous bone graft. These implants may be implanted via a variety of open or minimally invasive approaches.

The aprevo® TLIF-C Articulating System is indicated for use at one or more levels of the lumbosacral spine as an adjunct to fusion in patients with the following indications: degenerative disc disease (DDD), disc herniation (with myelopathy and/or radiculopathy), spondylolisthesis, deformity (degenerative scoliosis or kyphosis), spinal stenosis, and failed previous fusion (pseudarthrosis). DDD is defined as discogenic back pain with degeneration of the disc as confirmed by history and radiographic studies. These patients should be skeletally mature and have had at least six (6) months of non-operative treatment. aprevo® TLIF-C Articulating System devices are to be filled with autograft bone and/or allogenic bone graft composed of cancellous and/or corticocancellous bone. These devices are intended to be used with supplemental fixation systems that have been cleared for use in the thoracolumbosacral spine (e.g., posterior pedicle screw and rod systems). These implants may be implanted via a variety of open or minimally invasive approaches.

The aprevo® Cervical ACDF lnterbody System are interbody fusion devices indicated at one or more levels of the cervical spine (C2-T1) in patients with the following degenerative cervical conditions: cervical disc disease, instability, trauma including fractures, deformity defined as kyphosis, lordosis, or scoliosis, cervical spondylotic myelopathy, spinal stenosis, and failed previous fusion. Cervical disc disease is defined as discogenic pain with degeneration of the disc confirmed by history and radiographic studies. These patients should be skeletally mature and have had at least six (6) weeks of non-operative treatment. These devices are to be filled with autograft bone and/or allogenic bone graft composed of cancellous, cortical, and/or cortico-cancellous bone. The aprevo® Cervical ACDF lnterbody System must be used with supplemental fixation systems. For hyperlordotic corrections (≥20° lordosis), the system must be used with at least an anterior cervical plate as supplemental fixation.

The aprevo® Cervical ACDF-X lnterbody System are interbody fusion devices indicated at one or more levels of the cervical spine (C2-T1) in patients with the following degenerative cervical conditions: cervical disc disease, instability, trauma including fractures, deformity defined as kyphosis, lordosis, or scoliosis, cervical spondylotic myelopathy, spinal stenosis, and failed previous fusion. Cervical disc disease is defined as discogenic pain with degeneration of the disc confirmed by history and radiographic studies. These patients should be skeletally mature and have had at least six (6) weeks of non-operative treatment. These devices are to be filled with autograft bone and/or allogenic bone graft composed of cancellous, cortical, and/or cortico-cancellous bone. When used as a standalone system, the aprevo® Cervical ACDF-X lnterbody implant with integrated screw fixation is intended for use at multiple contiguous levels, or up to two levels when used in trauma, deformity or failed previous fusions. Deformity procedures to correct coronal angulation or any use of hyperlordotic correction (≥20°) must include supplemental fixation such as posterior cervical screw fixation or anterior plating.

Device Description

The aprevo® Lumbar Intervertebral Body Fusion Devices include ALIF, LLIF, TLIF, ALIF-X and TLIF-CA interbodies. The aprevo® lumbar interbody fusion devices are designed to stabilize the lumbar spinal column and facilitate fusion. The personalized aprevo® device incorporates patient specific features to allow the surgeon to tailor the procedure to the individual needs of the patient and includes an aperture intended for the packing of bone graft. The individualized surgical correction plan and device configurations are developed using patient CT scans. The aprevo® devices are manufactured from titanium alloy (Ti-6Al-4V) per ASTM F3001, while the screws that accompany ALIF-X are machined from material per ASTM F136. The devices are accompanied by an inserter instrument which facilitates the placement of the interbodies. Both the interbody devices and instruments are provided as single use, sterile-packed product to the end user.

The aprevo® Cervical Intervertebral Body Fusion Devices include ACDF, ACDF-X and ACDF-X no cams. The aprevo® Cervical ACDF System, which includes the aprevo® Cervical ACDF Interbody, aprevo® Cervical ACDF-X Interbody, and the aprevo® Cervical ACDF-X (NO CAM) Interbody are designed to stabilize the cervical spinal column and facilitate fusion. The personalized aprevo® devices incorporate patient-specific features to allow the surgeon to tailor the deformity correction to the individual needs of the patient and include an aperture for the packing of bone graft. The aprevo® Cervical ACDF System interbodies are additively manufactured from Ti-6Al-4V ELI titanium alloy per F3001, while the screws are machined from Ti alloy per ASTM F136. The devices are accompanied by an inserter instrument which facilitates the placement of the interbodies. Both the interbody devices and the instruments are provided to the end-user as single use, sterile-packed products.

The purpose of this 510(k) is to extend the expiration of imaging used to create 3D surgical plans. There have been no changes made to the software used in the surgical planning process.

AI/ML Overview

The provided FDA 510(k) clearance letter (K250827) for Carlsmed, Inc.'s "aprevo®" interbody fusion devices primarily concerns the renewal of previously cleared devices and the extension of the imaging expiration dating used for 3D surgical planning. Therefore, the document does not contain details of a clinical study assessing the performance of an AI-based device meeting acceptance criteria in the way one might expect for a novel AI/ML medical device submission.

Instead, the performance testing summary indicates that "Clinical data was used to evaluate imaging expiration. Expiration dating was validated using statistical analysis (DICE score) with an acceptance criterion of >0.80. Additionally, the performance was evaluated across key cohorts." This suggests that the "device" being evaluated for performance in this context is likely related to the software's ability to accurately segment or generate 3D models from imaging data over time, rather than the interbody fusion implants themselves. The clearance is for the physical implants, which are considered substantially equivalent to previously cleared predicates. The "performance testing" here seems to be an update or validation related to the software component of the surgical planning.

Given this context, I will extract information relevant to the software's performance, as that is the only "acceptance criteria" and "study" mentioned, even if it's not a typical AI model performance study against clinical outcomes.

Here's an interpretation based on the limited information provided, assuming the "device performance" refers to the imaging processing capabilities of the aprevo® system's software, specifically regarding the "expiration" of imaging data for 3D surgical plans:


Acceptance Criteria and Device Performance Study for Imaging Expiration

The context of this FDA 510(k) submission (K250827) indicates that the performance study was specifically undertaken to extend the expiration of imaging used to create 3D surgical plans. This suggests the "device performance" being assessed relates to the consistency and accuracy of the software's ability to process imaging data for surgical planning over time, implying that "aging" of the input imaging data does not degrade the software's output beyond an acceptable threshold.

1. Table of Acceptance Criteria and Reported Device Performance

MetricAcceptance CriteriaReported Device Performance
DICE Score (for imaging expiration/segmentation accuracy)> 0.80Not explicitly stated, but implied to meet the criterion as the 510(k) was cleared. The text says "Expiration dating was validated using statistical analysis (DICE score) with an acceptance criterion of >0.80."

Note: The document only specifies the acceptance criterion. The specific numerical performance result (e.g., the exact DICE score achieved) is not provided in this public clearance letter. However, the clearance implies that the criterion was met.

2. Sample Size and Data Provenance

  • Test Set Sample Size: Not specified in the provided text.
  • Data Provenance: "Clinical data was used." No details on the country of origin or whether the data was retrospective or prospective are provided.

3. Number of Experts and Qualifications for Ground Truth

  • Number of Experts: Not specified.
  • Qualifications of Experts: Not specified.

4. Adjudication Method for the Test Set

  • Adjudication Method: Not specified. (e.g., 2+1, 3+1, none).

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

  • MRMC Study Done?: No, an MRMC study comparing human readers with and without AI assistance is not mentioned or implied by the description of this performance evaluation, which focuses on "imaging expiration" and DICE score.

6. Standalone (Algorithm Only) Performance

  • Standalone Performance Done?: Yes, the use of a "DICE score" for "imaging expiration" strongly suggests an algorithm-only performance evaluation, likely comparing the software's segmentation or 3D reconstruction output against a form of ground truth derived from the clinical data. The phrase "There have been no changes made to the software used in the surgical planning process" further indicates an assessment of the software's intrinsic capabilities.

7. Type of Ground Truth Used

  • Type of Ground Truth: The use of "DICE score" typically implies that the ground truth involves expert-annotated segmentations or regions of interest within the medical images. The DICE score measures the spatial overlap between the algorithm's output and the ground truth. While not explicitly stated, it's highly probable that this ground truth was derived from expert consensus or manual annotation of anatomical structures on the clinical imaging data.

8. Sample Size for the Training Set

  • Training Set Sample Size: Not mentioned. This submission is for an extension/validation of existing software, not the initial clearance of a newly developed AI model, so details on original training are not typically included here.

9. How Ground Truth for the Training Set Was Established

  • Ground Truth Establishment for Training Set: Not mentioned. As above, this document focuses on a validation study for imaging expiration, not the initial development or training of the AI algorithm.

Summary of Limitations Based on Provided Text:

The provided 510(k) summary (specifically the "Performance Testing Summary") is extremely concise regarding details of the study. It states that "Clinical data was used to evaluate imaging expiration" and that "Expiration dating was validated using statistical analysis (DICE score) with an acceptance criterion of >0.80. Additionally, the performance was evaluated across key cohorts."

Therefore, many typical details requested for robust AI/ML performance studies, such as specific sample sizes, expert qualifications, and adjudication methods, are not present in this public clearance letter. This is common for 510(k) summaries, which are often condensed versions of the full submission. The key takeaway is that the "performance testing" here addresses a specific aspect ("imaging expiration" for 3D surgical planning) of the software rather than a direct clinical efficacy study of the implant or a broad AI diagnostic/prognostic model.

§ 888.3080 Intervertebral body fusion device.

(a)
Identification. An intervertebral body fusion device is an implanted single or multiple component spinal device made from a variety of materials, including titanium and polymers. The device is inserted into the intervertebral body space of the cervical or lumbosacral spine, and is intended for intervertebral body fusion.(b)
Classification. (1) Class II (special controls) for intervertebral body fusion devices that contain bone grafting material. The special control is the FDA guidance document entitled “Class II Special Controls Guidance Document: Intervertebral Body Fusion Device.” See § 888.1(e) for the availability of this guidance document.(2) Class III (premarket approval) for intervertebral body fusion devices that include any therapeutic biologic (e.g., bone morphogenic protein). Intervertebral body fusion devices that contain any therapeutic biologic require premarket approval.
(c)
Date premarket approval application (PMA) or notice of product development protocol (PDP) is required. Devices described in paragraph (b)(2) of this section shall have an approved PMA or a declared completed PDP in effect before being placed in commercial distribution.