ICD-10 Coding of Strain and Sprains and Proper use of A, D and S extensions

The coding for strains and sprains is more specific in ICD10 as there are separate codes for strains and sprains while ICD9 uses one code to designate strain or sprain.

For instance for cervical spine, 847.0 is used in ICD9 to indicate a strain and sprain while ICD10 has separate codes for each. The base code for cervical strain is S13.4 and cervical sprain is S16.1. However, to be complete the codes have to be to 7 characters in length with the 7th character and A, D, or S.

Therefore the specific codes are as follows;
S13.4XXA sprain of cervical spine, initial encounter
S13.4XXD sprain of cervical spine, subsequent encounter
S13.4XXS sprain of cervical spine, sequelae
S16.1XXA strain of cervical spine, initial encounter
S16.1XXD strain of cervical spine, subsequent encounter
S16.1XXS strain of cervical spine, sequelae

At first glance it may appear obvious and logical when you identify the coding in this format is that the initial encounter is for the first visit and subsequent encounter is for the second and “subsequent” visits. However, that assumption is incorrect and without a full understanding of the definitions of the A and D extensions may lead to improper coding.

The term “initial encounter” is somewhat misleading as it actually refers to the period of time when the patient is receiving active treatment for the condition. Chiropractic treatment (physical medicine services et al) are considered active treatment as there is “active care” for the condition. Therefore the A extension S13.4XXA for cervical sprain and S16.1XXA would be the code to use for all visits when the patient is under active care.

Subsequent encounter is the visit(s) after the active phase of treatment. For instance a medical provider refers a patient to a chiropractor for care and once care is completed with the chiropractor and the patient is being “checked” out by the medical provider that would be the subsequent encounter.

The source of these definitions ICD10 CM Documentation A How-To Guide for Coders, Physicians and HealthCare Facilities 2014 pages 341- 342 Chapter 19.

Medicare Local Coverage Determination LCD for chiropractic, specifically Noridian, lists the strain and sprain codes for spine with only the A extension, as it refers to care that is active therapy (think AT modifier for CMT as required by Medicare). Use of codes with a D extension is not payable by Noridian Medicare and this diagnosis indicates the patient is not under active (corrective care).

National Government Services another multistate Medicare intermediary also lists only the strain and sprain codes with the A extensions as well but also codes with the S extension for sequelae. Sequela refers to the complications or conditions that arise as a direct result of an injury (residual effects). This residual effect can be pain, scar tissue, loss of range of motion etc. Generally sequelae code such as S13.4XXS is coded secondary to the sequelae itself. For instance residual pain in the cervical spine following a sprain would be coded in this manner.

M54.2 cervical pain as primary and S13.4XXS indicating the pain is the sequelae of a cervical sprain.

While it is the provider’s duty to choose the most appropriate code the provider must also have a correct understanding of the code meanings. For strain and sprain codes in ICD10 the A extension does indicate initial encounter but is also for all dates of service when there is active care. Therefore the most likely code a chiropractic provider would use, unless the care is no longer active, corrective, or acute would be the A extension.