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 schematic and help relate subjective and objective data to a patient's condition.

Model[edit | edit source]

SINSS Model Graphic.png

ACHE Evaluation Schematic Model[edit | edit source]

This model was adapted by physiotherapists and faculty within the Arkansas Colleges of Health Education School of Physical Therapy. This model is utilized by students within the college when relating subjective and objective findings during the physical evaluation and examination. This model will be directly related to the SINSS model for fluidity when examining a case study.

Guidance Through a Case Study[edit | edit source]

To get an accurate representation of how to implement the SINSS model to a patient, 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.

  • 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. 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.

They were 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. They reported it as this.[edit | edit source]
  • pain at its best: 0/10
  • pain at its worst: 7/10
  • current pain: 2/10
They were then asked, are there any activities or movements that provoke symptoms of pain or irritation?[edit | edit source]

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

Finally they were asked if their injury had any effects on their normal daily activities.[edit | edit source]

They reported that they have trouble putting on their backpack, and 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.

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[4]. 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[5].

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].

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].

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[6].

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
  • 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]

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[7]. The condition can be:

  • Improving
  • Worsening
  • Not changing
  • Fluctuating

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 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. 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.
  5. Kareha SM, McClure PW, Fernandez-Fernandez A. Reliability and Concurrent Validity of Shoulder Tissue Irritability Classification. Phys Ther. 2021 Mar 3;101(3):pzab022.
  6. 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.
  7. 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.