M43.9Deforming dorsopathy, unspecified

M43.9 is the ICD-10-CM diagnosis code for deforming dorsopathy, unspecified. It belongs to category M43 (other deforming dorsopathies), block M40-M43 (deforming dorsopathies) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within M43, choose M43.9 (Deforming dorsopathy, unspecified) only when documentation doesn't support a more specific option: Spondylolysis (M43.0), spondylolisthesis (M43.1), fusion of spine (M43.2), recurrent atlantoaxial dislocation with myelopathy (M43.3), other recurrent atlantoaxial dislocation (M43.4), other recurrent vertebral dislocation (M43.5), torticollis (M43.6) and other specified deforming dorsopathies (M43.8).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 456 (Spinal Fusion Except Cervical with Spinal Curvature, Malignancy, or Infection with MCC, relative weight 7.6244), DRG 457 (Spinal Fusion Except Cervical with Spinal Curvature, Malignancy, or Infection with CC, relative weight 5.3668), DRG 458 (Spinal Fusion Except Cervical with Spinal Curvature, Malignancy, or Infection without CC/MCC, relative weight 4.0388), DRG 551 (Medical Back Problems with MCC, relative weight 1.6358) and DRG 552 (Medical Back Problems without MCC, relative weight 0.9584), in MDC 08 (Diseases and Disorders of the Musculoskeletal System and Connective Tissue), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 737.8 (other curvatures of spine).