Severity, Irritability, Nature, Stage and Stability (SINSS)

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Overview[edit | edit source]

The Severity, Irritability, Nature, Stage and Stability (SINSS) model is a clinical reasoning construct to provide clinicians with a structured framework for taking subjective history, in order to determine an appropriate objective examination and treatment plan, and reduce clinical reasoning errors[1].

The SINSS model helps the physiotherapist to find out detailed information about the patients' condition, filter and group the information, prioritize their problem list, and determine which tests should be used and when. This ensures information isn't omitted and the patient isn't under or over examined and/or treated[1]. The SINSS model is utilized and interpreted from clinical reasoning skills that involve psychomotor, cognitive, anatomical, and affective knowledge from the physiotherapist. Usage of the SINSS model is contextual to a patient's condition and relates perspectives from both the physiotherapist and the patient[2].

The SINSS model can be an effective tool to compare subjective patient reports and objective examination findings to help determine an accurate diagnosis and the scope of the patient's prognosis through effective clinical reasoning skills. Implementation of the SINSS model during evaluation can aid in understanding of the patient's condition and reduce the risk for clinician clinical reasoning errors[3]. Please note that due to the highly subjective nature of the SINSS model, its' application will vary on a case by case basis. The information and objective findings presented here will only be used to guide the clinician throughout the examination and evaluation process and help relate subjective and objective data from a patient's condition to the steps within the SINSS Model.

Model[edit | edit source]

SINSS Model Graphic.png

Guidance Through a Case Study[edit | edit source]

To get an accurate representation of how to implement the SINSS model to a patient, subjective and objective findings from a patient's examination will be used throughout this page as it relates to each step of the SINSS model and various steps from the evaluation process.

This patient gave consent to talk about their shoulder injury and how it has impacted their daily life since the original date of onset. A series of questions related to the patients condition were written and the patient filled out the list of questions to the best of their knowledge and ability.

  • Diagnosis of Patient: Partial sub-tendinous tear of the Supraspinatus < 3mm in the Right shoulder, secondary right shoulder instability and impingement.
  • Functional Questionnaire: Upper Extremity Functional Index (46/80 score).
  • Injury Onset Date: 1/24/2024
  • Previous injury history: Right shoulder dislocation in 2018.
  • MOI: Internal rotation of the right shoulder coupled with a popping noise and pain presence
  • Pain: Best- 0/10, Worst- 7/10, Daily average- 2/10 (pain described as sharp pains with movement accompanied with popping and catching and dull aches at rest or when the arm is hanging freely).
  • ROM: painful arc passed 90 degrees of abduction, pain with shoulder extension, pain at end range external rotation.
  • Functionality: Patient reports compensation and difficulty with ADL's. Pulling motions aggravate the shoulder joint and increase pain in the posterior shoulder specifically. Patient reports the shoulder feels weak and has not been able to lift more than 3 pounds with the right arm since the onset of injury.
  • Subjective information: The patient feels like their injury is improving even if it is slowly. Patient reports seeing progress in both strength and range of motion. The patient states they are limited in their daily life with pain when functioning and a fear of increasing the severity of their injury. Although the process has been hard, the patient stated they enjoy challenging themselves to get better and improve their overall condition.

Severity[edit | edit source]

Severity relates to the intensity of the symptoms, including subjective pain level. Amount, type and pattern of pain should be established. Pain can be measured in a multitude of ways, such as through the visual analogue scale (VAS). Using tools to help gauge the patient’s pain will help assist the clinician in objectively categorizing the symptoms and determining a focal point for treatment. Pain diagrams are beneficial for determining pain location and distribution to better treat a patient's condition[4] A patient’s perception of their pain can have a great impact on their recovery. A key determinant in the way severity is measured is the extent to which the patient’s activities of daily living (ADLs) are affected, as generally the more severe one’s pain is the more their ADLs are affected.

Considering the patient’s severity includes determining the suitable intensities used for the examination process.  Assessing the severity further lends itself to assessing the patients' prognosis and outcome, which supports the therapist in their overall treatment of the patient.   [1]

Example:[edit | edit source]

A patient is coming with a a diagnosed partial tear of the supraspinatus which is also causing glenohumeral instability and impingement. The patient was a series of questions to determine their "severity" or the effect it has on daily living.

The patient was first asked what their current level of pain on a scale of 0-10 as well as the level of pain at its worst and its best. The patient reported pain as:[edit | edit source]
  • Throbbing and sharp pain with sudden movement of the shoulder and sometimes dull aches at rest or when letting the arm hang freely by their side.
  • Pain at its best: 0/10
  • Pain at its worst: 7/10
  • Daily pain on average: 2/10

Pain is a subjective measure that varies from patient to patient but it can help determine the severity of an injury. Generally, pain can be associated with multiple stages of severity classified as:

  • Non-Severe: 0-3/10 pain
  • Minimally Severe: 4-7/10 pain
  • Severe: 8-10/10 pain

It is also important to understand the difference between pain types and how they play a role into staging of an injury.[5]

  • Acute pain can be associated with an injury usually surrounding a sudden onset. The type of pain most often described are sharp, shooting, throbbing pains in the affected area. This usually occurs days and up to 6 months after the initial onset date of the injury.[5]
  • Chronic pain can be associated with a disease state of pain that is due to an injury that has either improperly healed or has not settled. Chronic pain cannot be attributed to normal, established timelines of recovery and need to be treated differently and adapted with therapeutic intervention.[5]
The patient was then asked, are there any activities or movements that provoke symptoms of pain or irritation?[edit | edit source]

The patient reported that abduction past 90 degrees, shoulder extension, and pushing or pulling with involved arm.

Finally the patient was asked if their injury had any effects on their normal daily activities.[edit | edit source]

The patient reported that they have trouble with self care, putting on their backpack, and opening/shutting their door to their apartment.

Discussion[edit | edit source]

With this schematic being highly subjective, it means it is left up to the interpretation of the evaluator to determine the level of severity this injury is presenting. Based on the symptoms that are created by daily activities but their ability to still function adequately and associated compensation causing pain will present as a moderate severity. Moderate severity will inhibit the completion of ADL's and other provoking movements without the presence of pain or compensation (textbook ref). This can have an effect on therapy due to the severity and irritability of the patient's pain so modification of exercise may be necessary for successful treatment.

Irritability[edit | edit source]

Irritability can be assessed by establishing the level of activity required to aggravate the symptoms, how severe the symptoms are and how long it then takes for the symptoms to subside[6]. Irritability can also be judged by the ratio or aggravating factors to easing factors. The concept of tissue irritability was initially proposed by Maitland as the tissues ability to handle physical stress, however there are not widely used reliable or valid classifications for irritability[7].

The clinician should consider the patients' irritability when planning the evaluation and subsequent interventions. This understanding helps the clinician provide the most effective treatment. The clinician should also consider the extent to which they challenge the patient. This helps to prevent exacerbating the patients' symptoms unnecessarily[1].

Case Example:[edit | edit source]

The same patient that was asked questions about the severity of their ailment was also asked about the irritability of their ailment. Following this are the questions that were asked as well as the answers they gave.

Do you have any pain when moving through range of motion? If so, when does your pain occur?[edit | edit source]

This question is primarily looking for a painful arc and what movements may make the symptoms worse.

The patient responded as such, “ pain at 90 degrees of abduction, pain at 40 degrees of Glenohumeral(GH) extension, and pain at the end range of GH external rotation.”

Note: There is another evaluation step within this question that would alter the irritability assessment which was the end feel of these movements. The end feel is normally determined in order to evaluate the integrity of the joint, but in this case the end feel could not be evaluated due to the pain accompanying the movements. These questions were evaluating the tissue reactivity of the patients ailment which ultimately could not be determined, but aid in assessing irritability through functional measures.

Does pain ever inhibit normal functioning of your affected joint? If so does it completely inhibit function, impair the completion or is compensation required, or is there no pain with activity?[edit | edit source]

The questions seems to be extensive but this question is looking at the patient's ability to complete tasks this is called

Functional reactivity

It is up to the evaluating practitioner to determine the patients functional reactivity via their response with the example patient. The patient responded as such, “ I have had to change the way I perform some ADL’s to avoid pain.” The patient reported having to change their way of living with everyday tasks such as personal hygiene, self care tasks, putting on a backpack, and opening or shutting doors. The patient also stated feeling "apprehensive" and "cautious" when moving their shoulder quickly to avoid furthering their injury.

Are there certain movements or positions that make the pain worse? Is there a certain location that if provoked or moved too much, would it cause an increase in pain or symptoms?[edit | edit source]

These questions are used to determine the next evaluation part of irritability which is,

Aggravating factors

The patient responded to these questions as such; “ pushing and pulling. Pulling makes it worse.” They also said “I have pain in the posterior portion of my right joint capsule if I move too much or too quickly.”

Discussion[edit | edit source]

The patient in this case example was determined to have a moderate irritability due to the presence of pain with activities of daily living and marked compensation required to complete them. This was also determined by the fact that pain can be alleviated through conventional means such as ice and resting, Again it is up to the evaluating practitioner to take all of the questions and responses into account to determine the overall irritability of the patients ailment. These determinations may also influence what kind of exercises that you may move forward with. For example, if you determine the patient has a high irritability, you may start the patient off with more conservative treatment exercises or modalities.

Nature[edit | edit source]

Nature is a broad term relating to the patient's diagnosis, the type of symptoms and/or pain, personal characteristics/psychosocial factors, as well as red and yellow flags. Within this category a clinician should be able to recognize if the condition is within their scope of practice, as well as if the condition requires immediate action or special considerations [1].

Case example:[edit | edit source]

The questions focus on the patients pain or abnormal feelings within the patients involved joint. The following are the questions to determine the nature of the ailment as well as the patients response.

What is the general nature of your pain if present? If present, about how long does you pain last?[edit | edit source]

The patient responded as such; “sharp and dull aches,” “the pain usually lasts a few minutes”

The questions are focusing on the pains nature and length of time the pain will last.

When moving, do you experience any unnatural noises or feelings in your affected joint? If present, where is the majority of your pain? Does it radiate or is it in a specific spot?[edit | edit source]

The patient responded as such; “Popping and clicking,” they also state, “ my pain stays in either the posterior or anterior shoulder. Right after my injury, I had pain in the long head of my bicep, but that pain has not happened in around a month.”

Discussion[edit | edit source]

Again these questions focus on the pain that occurs from their ailment. The description of the pain is highly subjective and can differ from patient to patient, so the understanding of the patients view on pain is needed in order to completely understand how much pain the patient is experiencing. The interpretation of these questions and the patients pain is also subjective, there is no cut and dry method of determining the patients nature of pain.

Stage[edit | edit source]

Stage refers to the duration of the symptoms. Stage can be a useful to consider the inflammatory process and/or stage of healing. Every patient does not necessarily experience every stage of healing, nor is healing confined to these specified stage timeframes. The clinician may need to take into consideration a settled phase that occurs after the subacute phase and before the chronic stage is reached[8].

Stage classifications:

  • Acute: typically days-weeks (<3 weeks)              
  • Subacute: typically weeks (3-6 weeks)              
  • Chronic: typically weeks-months (>6 weeks)      
  • Acute stage of a chronic condition: recent exacerbation of symptoms of a condition that the patient has been experiencing for >6 weeks.[1]
  • Subacute stage of a chronic condition: later stage of exacerbation of symptoms of a condition that the patient has been experiencing for >6 weeks.[1]
Case example[edit | edit source]

The stage of healing questions are focused on how much pain is being experienced, how the patient feels about the integrity of the joint, and what potential stage of healing the injury is in.

Do you have an of the cardinal signs present in your affected joint? Generally, how would you describe the strength of your affected joint? When was the onset of injury?[edit | edit source]

The patient responded to these questions as such; “pain in the posterior and anterior joint capsule,” “I would say I’m very weak in my right arm(the affected arm), I have not been able to lift weights without pain since my injury, but recently I have been able to lift a 3 lb weight without pain.” “ Since my injury was almost 2 months ago, I would say I am in the chronic phase of healing.”

Discussion[edit | edit source]

The answers of these questions will depend on the type of pain, and general extent of healing. The patient may not know what the difference between chronic, sub acute, and acute means either so, it is up to the practitioner to determine the amount of healing that has occurred.

Stability[edit | edit source]

Stability refers to how the symptoms are progressing, which the clinician can use within the wider context to evaluate the effectiveness of their assessment and treatment, and to guide progression or regression of the intervention[9]. The condition can be:

  • Improving
  • Worsening
  • Not changing
  • Fluctuating
Case example[edit | edit source]

Stability is focusing on how the patient feels about their overall treatment process, as well as their psyche on the situation as a whole.

Do you feel your injury is improving, staying the same, or getting worse? How do you feel overall regarding your injury?[edit | edit source]

Conclusion[edit | edit source]

There are multiple models of clinical reasoning. SINSS presents a methodical approach that can benefit the clinician and the patient, by allowing the clinician to gain a deeper understanding of the patient's experience which can result in more appropriate interventions[1]. Additionally, the SINSS model can be beneficial in education when utilized by mentors and their students to help facilitate the clinical reasoning process [1]. While utilizing the SINSS model in the orthopedic setting may reduce clinical reasoning errors during the diagnostic and prognostic process as well as the intervention[1], the SINSS model requires further research to confirm that its use improves patient outcomes.

References[edit | edit source]

  1. 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 Petersen EJ, Thurmond SM, Jensen GM. Severity, Irritability, Nature, Stage, and Stability (SINSS): A clinical perspective. J Man Manip Ther. 2021 Oct;29(5):297-309
  2. Huhn K, Gilliland SJ , Black LL, Wainwright SF, Christensen N. Clinical Reasoning in Physical Therapy: A Concept Analysis. Physical Therapy. 2019 April; 99(4): 440–456
  3. Petersen EJ, Thurmond SM, Jensen GM. Severity, Irritability, Nature, Stage, and Stability (SINSS): A clinical perspective. J Man Manip Ther. 2021;29(5):297-309.
  4. Southerst D, Cote P, Stupar M, Stern P, Mior S. The Reliability of Body Pain Diagrams in the Quantitative Measurement of Pain Distribution and Location in Patients with Musculoskeletal Pain: A Systematic Review. Journal of Manipulative and Physiological Therapeutics. 2013 Sep; 36(7): 450-459.
  5. 5.0 5.1 5.2 Grichnik KP, Ferrante FM. The difference between acute and chronic pain. Mt Sinai J Med. 1991;58(3):217-220.
  6. Barakatt ET, Romano PS, Riddle DL, Beckett LA. The Reliability of Maitland's Irritability Judgments in Patients with Low Back Pain. J Man Manip Ther. 2009;17(3):135-40.
  7. Kareha SM, McClure PW, Fernandez-Fernandez A. Reliability and Concurrent Validity of Shoulder Tissue Irritability Classification. Phys Ther. 2021 Mar 3;101(3):pzab022.
  8. Baker SE, Painter EE, Morgan BC, Kaus AL, Petersen EJ, Allen CS, Deyle GD, Jensen GM. Systematic Clinical Reasoning in Physical Therapy (SCRIPT): Tool for the Purposeful Practice of Clinical Reasoning in Orthopedic Manual Physical Therapy. Phys Ther. 2017 Jan 1;97(1):61-70.
  9. Koury MJ, Scarpelli E. A manual therapy approach to evaluation and treatment of a patient with a chronic lumbar nerve root irritation. Phys Ther. 1994 Jun;74(6):548-60.