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Official Description

Arthrodesis, lateral extracavitary technique, including minimal discectomy to prepare interspace (other than for decompression); thoracic

© Copyright 2025 American Medical Association. All rights reserved.

Common Language Description

Arthrodesis by lateral extracavitary technique, including minimal discectomy to prepare the interspace (other than for decompression), is a surgical procedure aimed at fusing vertebral segments in the thoracic spine. This technique involves a lateral approach that necessitates the resection of ribs and exposure of the pleura and/or peritoneum, allowing for direct access to the spinal column. The procedure begins with a midline incision that is extended laterally to reveal the paraspinous muscle bundle over the targeted thoracic or lumbar vertebral segment. The paraspinous muscles are carefully elevated off the spinous processes and laminae to facilitate access to the underlying structures. During the operation, the paraspinous muscle bundle is divided and elevated off the ribs, which are then dissected from the intercostal muscles and pleura. The rib is resected, and the intercostal nerve is identified and protected to prevent damage. A high-speed drill is utilized to remove the associated transverse process and the lateral portion of the facet and pedicle, exposing the dural sac and vertebral body. In cases involving the lumbar spine, the peritoneum is also exposed and retracted to enhance visibility of the vertebral body. The procedure includes the removal of degenerated disc material to prepare the interspace for arthrodesis, followed by the decortication of the vertebral endplates. To facilitate the interbody arthrodesis, a separately reportable bone allograft or autograft is placed between the vertebral endplates. After the necessary interventions, drains may be placed as needed, and the incisions are subsequently closed. This comprehensive approach ensures that the vertebral segments are adequately prepared for fusion, promoting stability and recovery in the thoracic spine.

© Copyright 2025 Coding Ahead. All rights reserved.

1. Indications

The procedure of arthrodesis by lateral extracavitary technique is indicated for various conditions affecting the thoracic spine. These indications may include:

  • Degenerative Disc Disease The presence of degenerative changes in the intervertebral discs that may lead to pain and instability.
  • Spinal Instability Conditions that result in abnormal movement between vertebrae, necessitating stabilization through fusion.
  • Spinal Deformities Structural abnormalities of the spine, such as scoliosis or kyphosis, that may require correction and stabilization.
  • Trauma Fractures or injuries to the thoracic vertebrae that compromise spinal integrity and require surgical intervention.
  • Failed Conservative Treatment Patients who have not responded to non-surgical management options for spinal pain or instability.

2. Procedure

The arthrodesis procedure using the lateral extracavitary technique involves several critical steps to ensure successful fusion of the vertebral segments. The following procedural steps are performed:

  • Step 1: Incision and Exposure A midline incision is made and extended laterally to expose the paraspinous muscle bundle over the thoracic or lumbar vertebral segment targeted for fusion. This initial step is crucial for gaining access to the underlying structures.
  • Step 2: Muscle Elevation The paraspinous muscles are carefully elevated off the spinous processes and laminae. This elevation allows for a clear view of the vertebrae and surrounding tissues necessary for the procedure.
  • Step 3: Rib Resection The paraspinous muscle bundle is divided and elevated off the ribs. The rib is then dissected from the intercostal muscles and pleura, followed by resection of the rib to facilitate access to the spinal column.
  • Step 4: Nerve Protection The intercostal nerve is identified and protected during the procedure to prevent any potential nerve damage that could lead to complications.
  • Step 5: Bone Removal A high-speed drill is utilized to remove the associated transverse process and the lateral portion of the facet and pedicle, exposing the dural sac and vertebral body for further intervention.
  • Step 6: Disc Material Removal Degenerated disc material is removed to prepare the interspace for arthrodesis. This step is essential for ensuring that the fusion site is clean and ready for graft placement.
  • Step 7: Endplate Preparation Cartilage is removed from the vertebral endplates, and the bone is decorticated to enhance the fusion process. This preparation is vital for promoting bone growth and successful fusion.
  • Step 8: Graft Placement A separately reportable bone allograft or autograft is placed between the vertebral endplates to facilitate the interbody arthrodesis, providing the necessary biological material for fusion.
  • Step 9: Closure Drains may be placed as needed to manage any potential fluid accumulation, and the incisions are closed to complete the procedure.

3. Post-Procedure

After the arthrodesis procedure, patients are typically monitored for any complications and provided with post-operative care instructions. Expected recovery may involve pain management, physical therapy, and gradual return to normal activities. The surgical site should be kept clean and dry, and any signs of infection or unusual symptoms should be reported to the healthcare provider. Follow-up appointments are essential to assess the healing process and ensure that the fusion is progressing as expected. The overall recovery timeline may vary based on individual patient factors and the extent of the surgery performed.

Short Descr ARTHRD LAT XTRCVTRY TQ THRC
Medium Descr ARTHRODESIS LATERAL EXTRACAVITARY THORACIC
Long Descr Arthrodesis, lateral extracavitary technique, including minimal discectomy to prepare interspace (other than for decompression); thoracic
Status Code Active Code
Global Days 090 - Major Surgery
PC/TC Indicator (26, TC) 0 - Physician Service Code
Multiple Procedures (51) 2 - Standard payment adjustment rules for multiple procedures apply.
Bilateral Surgery (50) 0 - 150% payment adjustment for bilateral procedures does NOT apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 2 - Payment restriction for assistants at surgery does not apply to this procedure...
Co-Surgeons (62) 2 - Co-surgeons permitted and no documentation required if the two- specialty requirement is met.
Team Surgery (66) 0 - Team surgeons not permitted for this procedure.
Diagnostic Imaging Family 99 - Concept Does Not Apply
APC Status Indicator Inpatient Procedures, not paid under OPPS
Type of Service (TOS) 2 - Surgery
Berenson-Eggers TOS (BETOS) P3D - Major procedure, orthopedic - other
MUE 1
CCS Clinical Classification 158 - Spinal fusion

This is a primary code that can be used with these additional add-on codes.

20705 Add-on Code MPFS Status: Active Code APC N Removal of drug-delivery device(s), intra-articular (List separately in addition to code for primary procedure)
20930 Addon Code MPFS Status: Bundled Code APC N ASC N1 CPT Assistant Article Allograft, morselized, or placement of osteopromotive material, for spine surgery only (List separately in addition to code for primary procedure)
20931 Addon Code MPFS Status: Active Code APC N ASC N1 CPT Assistant Article Allograft, structural, for spine surgery only (List separately in addition to code for primary procedure)
20936 Addon Code MPFS Status: Bundled Code APC N ASC N1 CPT Assistant Article Autograft for spine surgery only (includes harvesting the graft); local (eg, ribs, spinous process, or laminar fragments) obtained from same incision (List separately in addition to code for primary procedure)
20937 Addon Code MPFS Status: Active Code APC N ASC N1 CPT Assistant Article Autograft for spine surgery only (includes harvesting the graft); morselized (through separate skin or fascial incision) (List separately in addition to code for primary procedure)
20938 Addon Code MPFS Status: Active Code APC N ASC N1 CPT Assistant Article Autograft for spine surgery only (includes harvesting the graft); structural, bicortical or tricortical (through separate skin or fascial incision) (List separately in addition to code for primary procedure)
20939 Addon Code MPFS Status: Active Code APC N ASC N1 Bone marrow aspiration for bone grafting, spine surgery only, through separate skin or fascial incision (List separately in addition to code for primary procedure)
22534 Addon Code MPFS Status: Active Code APC C Physician Quality Reporting Illustration for Code Arthrodesis, lateral extracavitary technique, including minimal discectomy to prepare interspace (other than for decompression); thoracic or lumbar, each additional vertebral segment (List separately in addition to code for primary procedure)
22840 Addon Code MPFS Status: Active Code APC N ASC N1 Physician Quality Reporting CPT Assistant Article Posterior non-segmental instrumentation (eg, Harrington rod technique, pedicle fixation across 1 interspace, atlantoaxial transarticular screw fixation, sublaminar wiring at C1, facet screw fixation) (List separately in addition to code for primary procedure)
22841 Addon Code MPFS Status: Bundled Code APC C Physician Quality Reporting CPT Assistant Article Internal spinal fixation by wiring of spinous processes (List separately in addition to code for primary procedure)
22842 Addon Code MPFS Status: Active Code APC N ASC N1 Physician Quality Reporting CPT Assistant Article Posterior segmental instrumentation (eg, pedicle fixation, dual rods with multiple hooks and sublaminar wires); 3 to 6 vertebral segments (List separately in addition to code for primary procedure)
22843 Addon Code MPFS Status: Active Code APC C Physician Quality Reporting CPT Assistant Article Posterior segmental instrumentation (eg, pedicle fixation, dual rods with multiple hooks and sublaminar wires); 7 to 12 vertebral segments (List separately in addition to code for primary procedure)
22844 Addon Code MPFS Status: Active Code APC C Physician Quality Reporting CPT Assistant Article Posterior segmental instrumentation (eg, pedicle fixation, dual rods with multiple hooks and sublaminar wires); 13 or more vertebral segments (List separately in addition to code for primary procedure)
22845 Addon Code MPFS Status: Active Code APC N ASC N1 Physician Quality Reporting CPT Assistant Article Illustration for Code Anterior instrumentation; 2 to 3 vertebral segments (List separately in addition to code for primary procedure)
22846 Addon Code MPFS Status: Active Code APC C Physician Quality Reporting CPT Assistant Article Illustration for Code Anterior instrumentation; 4 to 7 vertebral segments (List separately in addition to code for primary procedure)
22847 Addon Code MPFS Status: Active Code APC C Physician Quality Reporting CPT Assistant Article Illustration for Code Anterior instrumentation; 8 or more vertebral segments (List separately in addition to code for primary procedure)
22848 Addon Code MPFS Status: Active Code APC N Physician Quality Reporting CPT Assistant Article Pelvic fixation (attachment of caudal end of instrumentation to pelvic bony structures) other than sacrum (List separately in addition to code for primary procedure)
22853 CPT Add On MPFS Status: Active Code APC N ASC N1 Insertion of interbody biomechanical device(s) (eg, synthetic cage, mesh) with integral anterior instrumentation for device anchoring (eg, screws, flanges), when performed, to intervertebral disc space in conjunction with interbody arthrodesis, each interspace (List separately in addition to code for primary procedure)
22854 CPT Add On MPFS Status: Active Code APC N ASC N1 Insertion of intervertebral biomechanical device(s) (eg, synthetic cage, mesh) with integral anterior instrumentation for device anchoring (eg, screws, flanges), when performed, to vertebral corpectomy(ies) (vertebral body resection, partial or complete) defect, in conjunction with interbody arthrodesis, each contiguous defect (List separately in addition to code for primary procedure)
22859 CPT Add On CPT Resequenced MPFS Status: Active Code APC N ASC N1 Insertion of intervertebral biomechanical device(s) (eg, synthetic cage, mesh, methylmethacrylate) to intervertebral disc space or vertebral body defect without interbody arthrodesis, each contiguous defect (List separately in addition to code for primary procedure)
51 Multiple procedures: when multiple procedures, other than e/m services, physical medicine and rehabilitation services or provision of supplies (eg, vaccines), are performed at the same session by the same individual, the primary procedure or service may be reported as listed. the additional procedure(s) or service(s) may be identified by appending modifier 51 to the additional procedure or service code(s). note: this modifier should not be appended to designated "add-on" codes (see appendix d).
AS Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery
22 Increased procedural services: when the work required to provide a service is substantially greater than typically required, it may be identified by adding modifier 22 to the usual procedure code. documentation must support the substantial additional work and the reason for the additional work (ie, increased intensity, time, technical difficulty of procedure, severity of patient's condition, physical and mental effort required). note: this modifier should not be appended to an e/m service.
58 Staged or related procedure or service by the same physician or other qualified health care professional during the postoperative period: it may be necessary to indicate that the performance of a procedure or service during the postoperative period was: (a) planned or anticipated (staged); (b) more extensive than the original procedure; or (c) for therapy following a surgical procedure. this circumstance may be reported by adding modifier 58 to the staged or related procedure. note: for treatment of a problem that requires a return to the operating/procedure room (eg, unanticipated clinical condition), see modifier 78.
59 Distinct procedural service: under certain circumstances, it may be necessary to indicate that a procedure or service was distinct or independent from other non-e/m services performed on the same day. modifier 59 is used to identify procedures/services, other than e/m services, that are not normally reported together, but are appropriate under the circumstances. documentation must support a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion, or separate injury (or area of injury in extensive injuries) not ordinarily encountered or performed on the same day by the same individual. however, when another already established modifier is appropriate it should be used rather than modifier 59. only if no more descriptive modifier is available, and the use of modifier 59 best explains the circumstances, should modifier 59 be used. note: modifier 59 should not be appended to an e/m service. to report a separate and distinct e/m service with a non-e/m service performed on the same date, see modifier 25.
62 Two surgeons: when 2 surgeons work together as primary surgeons performing distinct part(s) of a procedure, each surgeon should report his/her distinct operative work by adding modifier 62 to the procedure code and any associated add-on code(s) for that procedure as long as both surgeons continue to work together as primary surgeons. each surgeon should report the co-surgery once using the same procedure code. if additional procedure(s) (including add-on procedure(s) are performed during the same surgical session, separate code(s) may also be reported with modifier 62 added. note: if a co-surgeon acts as an assistant in the performance of additional procedure(s), other than those reported with the modifier 62, during the same surgical session, those services may be reported using separate procedure code(s) with modifier 80 or modifier 82 added, as appropriate.
78 Unplanned return to the operating/procedure room by the same physician or other qualified health care professional following initial procedure for a related procedure during the postoperative period: it may be necessary to indicate that another procedure was performed during the postoperative period of the initial procedure (unplanned procedure following initial procedure). when this procedure is related to the first, and requires the use of an operating/procedure room, it may be reported by adding modifier 78 to the related procedure. (for repeat procedures, see modifier 76.)
79 Unrelated procedure or service by the same physician or other qualified health care professional during the postoperative period: the individual may need to indicate that the performance of a procedure or service during the postoperative period was unrelated to the original procedure. this circumstance may be reported by using modifier 79. (for repeat procedures on the same day, see modifier 76.)
80 Assistant surgeon: surgical assistant services may be identified by adding modifier 80 to the usual procedure number(s).
82 Assistant surgeon (when qualified resident surgeon not available): the unavailability of a qualified resident surgeon is a prerequisite for use of modifier 82 appended to the usual procedure code number(s).
CR Catastrophe/disaster related
GC This service has been performed in part by a resident under the direction of a teaching physician
XS Separate structure, a service that is distinct because it was performed on a separate organ/structure
XU Unusual non-overlapping service, the use of a service that is distinct because it does not overlap usual components of the main service
Date
Action
Notes
2022-01-01 Note Short description changed.
2007-01-01 Changed Code description changed.
2004-01-01 Added First appearance in code book in 2004.
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