Title & Abstract

International Journal of Anatomy and Research

Effectiveness of Saturated Salt Solution to Embalm Cadavers in Comparison to Thiel Solution and Formalin Solution for Surgical Skill Training

DOI: 10.16965/ijar.2026.205

N.S, Ashwini ¹

ABSTRACT

Background.

Human cadavers are invaluable resources for anatomical education and surgical skill training. Cadaver-based simulation allows surgeons to practice operative techniques in a controlled environment without risk to patients. The quality of surgical training depends greatly on the preservation method used, as embalming influences tissue consistency, flexibility, colour, joint mobility and similarity to living tissues. Formalin embalming remains the most widely used preservation technique because of its excellent fixation, antimicrobial activity and long-term preservation. However, formalin-fixed tissues become rigid, lose elasticity and demonstrate altered handling characteristics, limiting their usefulness for advanced surgical simulation. Alternative methods such as Thiel embalming and saturated salt solution (SSS) embalming have been developed to provide improved tissue realism. Although Thiel embalming provides excellent tissue quality, its complex preparation and higher cost restrict widespread application.

Aim.

To compare the effectiveness of saturated salt solution embalming with Thiel and formalin embalming methods for cadaver-based surgical skill training.

Materials and Methods.

A pilot comparative observational study was conducted using 3 adult human cadavers obtained through the institutional body donation programme. Each cadaver was preserved using one of three embalming techniques: formalin solution (FS), saturated salt solution (SSS), and Thiel solution (TS). Cadaver suitability for surgical skill training was assessed by clinicians using a structured five-point rating scale. Parameters evaluated included tissue appearance, colour, texture, tactile sensation, surgical handling and overall usefulness for training procedures. Range of motion (ROM) of major joints was measured bilaterally using a standard goniometer.

Results.

Formalin-preserved cadavers demonstrated increased tissue stiffness and reduced joint mobility compared with SSS- and Thiel-preserved cadavers. Clinicians rated SSS and Thiel-preserved cadavers as more similar to living tissues in terms of handling characteristics and usefulness for surgical training. The SSS method showed comparable performance to Thiel embalming in surgical skill assessment. The mean clinician suitability scores were 2.87, 4.57 and 4.83 for formalin, SSS and Thiel embalming respectively. Joint mobility measurements demonstrated better preservation of movements in SSS and Thiel groups compared with formalin preservation.

Conclusion.

Saturated salt solution embalming provides a simple, economical and effective alternative to conventional formalin preservation for cadaver-based surgical skill training. It offers tissue handling characteristics comparable to Thiel embalming while requiring fewer resources, making it suitable for wider implementation in anatomy departments and surgical training centres.

Keywords: Cadaver preservation; Saturated salt solution; Thiel embalming; Formalin fixation; Surgical skill training; Anatomy education; Embalming technique

INTRODUCTION

Human cadaveric dissection has been an essential component of medical education since the development of modern anatomy [1,2]. Beyond undergraduate anatomical teaching, cadavers have become increasingly important models for postgraduate surgical training, procedural simulation and evaluation of emerging surgical techniques [3]. Cadaver-based surgical training allows clinicians to practice complex procedures in a controlled environment without compromising patient safety [4-6].

The suitability of cadavers for surgical simulation largely depends on the preservation technique employed. The ideal embalming method should maintain anatomical structures, preserve tissue colour and consistency, prevent decomposition and microbial contamination, and provide realistic handling characteristics similar to living tissue [3,6-11]. Formalin-based embalming has been the standard preservation technique for more than a century due to its excellent fixation properties, antimicrobial activity and long-term preservation capability. However, formaldehyde cross-links tissue proteins resulting in increased rigidity, loss of elasticity, altered tissue texture and reduced joint mobility. These changes limit its effectiveness for advanced surgical simulation. In addition, formaldehyde exposure is associated with occupational health concerns among healthcare workers and anatomy personnel [3,6-11].

Thiel's embalming method, introduced by Walter Thiel, has gained popularity due to its ability to preserve natural colour, flexibility and tissue consistency. Thiel-embalmed cadavers have demonstrated usefulness in various surgical disciplines including minimally invasive surgery, orthopaedics, urology and vascular procedures. However, the technique requires multiple chemical components, prolonged preparation and specialized facilities, making it expensive and difficult to implement in resource-limited settings [4,5,8].

The saturated salt solution (SSS) embalming method has emerged as a promising alternative. It uses sodium chloride as a major preservative component along with additional antimicrobial and tissue-preserving agents. Previous studies have demonstrated that SSS-embalmed cadavers provide realistic tissue handling characteristics and are suitable for surgical skill training. The method is comparatively inexpensive, technically simpler and requires less complex preparation than Thiel embalming [1,2,6]. The present study was undertaken to compare saturated salt solution, Thiel's method and conventional formalin embalming techniques with respect to surgical training suitability and joint mobility.

AIM AND OBJECTIVES

The aim of the study was to evaluate the effectiveness of saturated salt solution embalming for cadaver-based surgical skill training in comparison with Thiel's method and conventional formalin embalming. Specific objectives were: 1. To compare the suitability of cadavers embalmed by formalin solution, saturated salt solution and Thiel's method for surgical skill training; 2. To evaluate and compare the range of motion of joints in cadavers preserved using the three embalming techniques.

MATERIALS AND METHODS

This observational comparative study was conducted in the Department of Anatomy, Sri Devaraj Urs Medical College, Sri Devaraj Urs Academy of Higher Education and Research, Kolar, Karnataka, India, following approval from the Institutional Ethics Committee. Three fresh adult human cadavers obtained through the institutional body donation programme were preserved using: 1) Formalin solution (FS); 2) Saturated salt solution (SSS); and 3) Thiel's solution (TS). Exclusion criteria included previously embalmed or formalin-fixed bodies, decomposed or autopsied cadavers, and those with significant trauma.

Embalming Procedures and Solution Compositions

For FS embalming, arterial perfusion via the common carotid artery was performed using a standard formalin mixture (20% formaldehyde 4.0 L, phenol 0.4 L, glycerol 1.0 L, water 14.6 L; final volume 22 L). For SSS embalming, arterial perfusion was performed with saturated sodium chloride (20 kg), formaldehyde (1.0 L), phenol (0.2 L), glycerol (0.5 L), isopropyl alcohol (4.0 L), and water (19.3 L; final volume 25 L). For TS embalming, sequential preparation of stem solutions A (4-chloro-3-methylphenol, propylene glycol), B (ammonium nitrate, hot water), C (boric acid, potassium nitrate, hot water), stock solution, and final solution (sodium sulphite, morpholine, ethanol, 20% formaldehyde) was used, followed by tank immersion for 2-3 months prior to evaluation (Tables 1 and 5).

Table 1

Composition of Different Embalming Solutions.

Formalin Solution (FS) | Thiel Solution (TS) | Saturated Salt Solution (SSS)
20% Formaldehyde | A. Stem Solution A: 4-Chloro-3-methylphenol, Propylene glycol | Sodium chloride
Phenol | B. Stem Solution B: Ammonium nitrate, Hot water | 20% Formaldehyde
Glycerine | C. Stem Solution C: Boric acid, Potassium nitrate, Hot water | Phenol
Water | D. Stock solution: Stem A + Stem B + Stem C + Propylene glycol + Hot water | Glycerine
- | E. Final solution: Stock solution + Sodium sulphite + 20% Formaldehyde + Morpholine + Ethanol | Isopropyl alcohol, Water

Surgical Skill Training Suitability and Joint Goniometry

Ten blinded experienced clinicians across surgical specialties (General Surgery, Plastic Surgery, Orthopaedics, ENT, Ophthalmology, Anaesthesia, Emergency Medicine, General Medicine, OBG) performed simulation procedures (skin incision/suturing, vascular exposure/ligation/repair, central venous catheterisation, tracheostomy, chest tube insertion, lumbar puncture, ultrasound guidance, abdominal/pelvic packing). Tissue color, consistency, flexibility, tactile sensation, handling, and overall usefulness were scored on a 5-point Likert scale (1 = completely different from living tissue to 5 = completely similar). Range of motion (ROM) of shoulder, elbow, wrist, hip, knee, and ankle joints was measured bilaterally using a standard 15-cm goniometer.

RESULTS

Individual evaluator scores and mean suitability metrics demonstrated marked differences across embalming techniques (Tables 2 and 3). Formalin-fixed cadavers ranked lowest across all parameters, with an overall mean suitability score of 2.87/5 (tissue color: 3.2, consistency: 2.8, flexibility: 2.4, tactile sensation: 2.8, handling: 3.0, overall usefulness: 3.0). SSS-embalmed cadavers showed marked tissue realism with an overall score of 4.57/5 (color: 4.4, consistency: 4.6, flexibility: 4.4, tactile sensation: 4.6, handling: 4.6, usefulness: 4.8), which was comparable to Thiel preservation (overall score 4.83/5; color: 4.6, consistency: 4.8, flexibility: 4.8, tactile sensation: 5.0, handling: 4.8, usefulness: 5.0).

Goniometric range of motion (ROM) measurements across major joints demonstrated superior mobility in SSS and Thiel groups compared to formalin fixation (Table 4). Shoulder flexion reached 80-90° in SSS/TS vs. 20-35° in FS; shoulder abduction reached 100° in SSS/TS vs. 40° in FS. Hip flexion reached 60-75° in SSS/TS vs. 10-20° in FS, and knee flexion reached 70-75° in SSS/TS vs. 30° in FS. Joint mobility between SSS and Thiel cadavers showed no significant differences.

Table 2

Individual Evaluator Scores (5-point scale).

Evaluator | Method | Colour | Consistency | Flexibility | Tactile sensation | Handling | Overall usefulness
1 | FS | 3 | 3 | 2 | 3 | 3 | 3
2 | FS | 3 | 2 | 3 | 2 | 3 | 3
3 | FS | 3 | 3 | 2 | 3 | 3 | 3
4 | FS | 4 | 3 | 3 | 3 | 3 | 3
5 | FS | 3 | 3 | 2 | 3 | 3 | 3
6 | SSS | 4 | 5 | 4 | 5 | 4 | 5
7 | SSS | 4 | 4 | 5 | 4 | 5 | 4
8 | SSS | 5 | 5 | 4 | 5 | 5 | 5
9 | SSS | 4 | 4 | 5 | 4 | 4 | 5
10 | SSS | 5 | 5 | 4 | 5 | 5 | 5
11 | Thiel | 5 | 5 | 5 | 5 | 5 | 5
12 | Thiel | 4 | 5 | 5 | 5 | 5 | 5
13 | Thiel | 5 | 5 | 4 | 5 | 5 | 5
14 | Thiel | 5 | 4 | 5 | 5 | 4 | 5
15 | Thiel | 4 | 5 | 5 | 5 | 5 | 5

Table 3

Mean Suitability Scores by Embalming Method.

Parameter | Formalin Solution | Saturated Salt Solution | Thiel Solution
Tissue colour | 3.2 | 4.4 | 4.6
Tissue consistency | 2.8 | 4.6 | 4.8
Tissue flexibility | 2.4 | 4.4 | 4.8
Tactile sensation | 2.8 | 4.6 | 5
Surgical handling | 3 | 4.6 | 4.8
Overall usefulness | 3 | 4.8 | 5
Overall mean score | 2.87 | 4.57 | 4.83

Table 4

Range of motion of joints in formalin, saturated salt solution and Thiel fixed cadaver (degrees).

Joint | Movements | FS Right | FS Left | SSS Right | SSS Left | TS Right | TS Left
Shoulder Joint | Flexion | 35 | 20 | 80 | 90 | 80 | 90
Shoulder Joint | Extension | 30 | 30 | 50 | 50 | 45 | 50
Shoulder Joint | Abduction | 40 | 40 | 100 | 100 | 100 | 100
Shoulder Joint | Medial rotation | 50 | 50 | 60 | 70 | 65 | 75
Shoulder Joint | Lateral rotation | 10 | 10 | 30 | 40 | 35 | 40
Elbow Joint | Flexion | 100 | 100 | 110 | 100 | 100 | 110
Elbow Joint | Extension | -10 | 0 | 10 | 10 | 10 | 10
Wrist Joint | Flexion | 20 | 30 | 60 | 60 | 65 | 55
Wrist Joint | Extension | 20 | 30 | 60 | 60 | 60 | 60
Hip Joint | Flexion | 20 | 10 | 60 | 70 | 65 | 75
Hip Joint | Extension | 0 | 0 | 0 | 0 | 0 | 0
Hip Joint | Adduction | 10 | 10 | 10 | 15 | 15 | 15
Hip Joint | Abduction | 15 | 10 | 20 | 20 | 20 | 25
Hip Joint | Medial rotation | 5 | 5 | 20 | 20 | 20 | 25
Hip Joint | Lateral rotation | 10 | 10 | 20 | 25 | 20 | 25
Knee Joint | Flexion | 30 | 30 | 70 | 75 | 75 | 75
Knee Joint | Extension | 0 | 0 | 80 | 70 | 70 | 80
Ankle Joint | Plantar Flexion | 30 | 20 | 30 | 40 | 40 | 40
Ankle Joint | Dorsiflexion | 10 | 10 | 15 | 10 | 10 | 10

Abbreviations: FS = Formalin solution, SSS = Saturated salt solution, TS = Thiel's solution.

DISCUSSION

Cadaver-based surgical skill training provides an essential bridge between anatomical education and live operative practice. The efficacy of procedural simulation depends fundamentally on preservation quality [1-3]. Conventional formalin embalming creates rigid cross-linked methylene bridges among tissue proteins, resulting in excessive hardening, loss of elasticity, and restricted joint movement that hinder advanced surgical simulations and laparoscopic or flap procedures [3,6,11].

Thiel's method maintains natural color, pliability, and tissue planes, rendering it highly effective for urological, orthopaedic, and laparoscopic training [4,5,8]. However, its complex sequential formulation (stems A, B, C, morpholine, and propylene glycol), prolonged immersion requirement, and high cost restrict its widespread institutional adoption [4,6].

Saturated salt solution (SSS) embalming represents a practical, cost-effective alternative. The combination of saturated sodium chloride (osmotic preservation and microbial inhibition), glycerol (hydration and flexibility), low-concentration formaldehyde, phenol, and isopropyl alcohol yields pliable tissues, patent vascular lumens, and lifelike surgical planes [1,2,6]. Evaluators found SSS cadavers highly suitable for diverse procedures including vascular exposure/repair, tracheostomy, chest tube insertion, and flap elevation [1,2,9]. Table 5 outlines the detailed formulations utilized.

Study limitations include the pilot sample size (3 cadavers), lack of quantitative biomechanical tensile testing, and absence of long-term microbiological surveillance. Future multi-center evaluations with objective tissue testing are recommended.

Table 5

Showing the embalming methods with components.

Embalming Method | Major Components | Quantity/Concentration Used in Present Study
Formalin-based embalming (FS) | Formaldehyde solution | 20% formaldehyde - 4.0 L
Formalin-based embalming (FS) | Phenol | 0.4 L
Formalin-based embalming (FS) | Glycerol | 1.0 L
Formalin-based embalming (FS) | Water (vehicle) | 14.6 L
Formalin-based embalming (FS) | Final volume | 22 L
Thiel embalming technique (TS) | 4-Chloro-3-methylphenol | 66 g
Thiel embalming technique (TS) | Propylene glycol | 0.66 L
Thiel embalming technique (TS) | Ammonium nitrate | 2500 g
Thiel embalming technique (TS) | Boric acid | 370 g
Thiel embalming technique (TS) | Potassium nitrate | 620 g
Thiel embalming technique (TS) | Sodium sulphite | 800 g
Thiel embalming technique (TS) | Morpholine | 0.3 L
Thiel embalming technique (TS) | Ethanol | 1.3 L
Thiel embalming technique (TS) | Formaldehyde solution | 0.6 L
Thiel embalming technique (TS) | Water and propylene glycol | As required for preparation
Saturated salt solution (SSS) | Sodium chloride (saturated solution) | 20 kg
Saturated salt solution (SSS) | Formaldehyde solution | 1.0 L
Saturated salt solution (SSS) | Phenol | 0.2 L
Saturated salt solution (SSS) | Glycerol | 0.5 L
Saturated salt solution (SSS) | Isopropyl alcohol | 4.0 L
Saturated salt solution (SSS) | Water | 19.3 L
Saturated salt solution (SSS) | Final volume | 25 L

CONCLUSION

Saturated salt solution embalming provides a simple, economical, and effective preservation technique for cadaver-based surgical skill training. It offers tissue pliability, tactile feedback, and joint range of motion comparable to Thiel embalming while eliminating technical complexity and excessive chemical costs, making it highly suitable for wider adoption in surgical simulation and anatomy training centres.

Abbreviations & Declarations

DECLARATIONS

Ethical Approval: Approved by the Institutional Ethics Committee of Sri Devaraj Urs Academy of Higher Education and Research; cadavers obtained through the institutional voluntary body donation programme.

Funding: No external funding was received for this study.

Conflicts of Interest: The authors declare that there are no conflicts of interest.

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