Suspensory Materials for Surgery of Blepharoptosis: A Systematic Review of Observational Studies

Delayed infections following polybutylate-coated polyester (Ethibond) suture frontalis suspension surgery for severe blepharoptosis

PURPOSE

To describe the incidence and management of delayed infections following frontalis sling suspension with polybutylate-coated polyester suture (Ethibond).

METHODS

Retrospective, interventional case series of 177 eyes of 150 patients, who underwent frontalis suspension surgery with Ethibond (Johnson and Johnson, USA), at L V Prasad Eye Institute, Hyderabad, India, between January 2016 and February 2022. Patients were assessed for chronic secondary sling infection, defined as infection/suture granuloma occurring beyond 6 weeks post-surgery. All patients received postoperative oral antibiotics. The clinical profile, microbiological evaluation, antibiotic sensitivity patterns, and management outcomes were analyzed.

RESULTS

Delayed infection following Ethibond sling suspension was noted in 14 eyes of 13 patients (7.9%). Of these, eight cases (61.5%) were females. The average time interval from surgery to presentation was 7.5 months (range: 2.5 months to 2.5 years). Eleven eyes underwent sling removal. Of the three who received initial antibiotic course, two eventually needed sling removal. Microbiological evaluation was available in seven eyes (50%), with Staphylococcus aureus as the most common organism. Of the six positive cultures, five (83.3%) were resistant to fluoroquinolones (FQs).

CONCLUSION

Frontalis suspension with Ethibond has an 8% incidence of delayed infections, with Staphylococcus aureus as the most common organism. The authors recommend early sling removal in all patients with infection and recommend consideration of an alternative material in the event of future revision surgery.

Outcomes for expanded polytetrafluoroethylene strip in frontalis suspension surgery

PURPOSE

This study evaluates surgical outcomes and complication rates of frontalis suspension with expanded polytetrafluoroethylene (ePTFE).

METHODS

This retrospective cohort study reviewed all patients undergoing frontalis suspension surgery using ePTFE as the sling material from January 1 2012 to March 3 2020 by a single surgeon at a single academic center. Two different surgical techniques were evaluated in the placement of the sling material. Demographic, clinical, and operative data were extracted. Outcome data including postoperative lid height, reoperation, and complication rate were extracted for the cohort and compared between the two surgical techniques. Descriptive statistics were utilized.

RESULTS

Sixty-four eyes from 49 unique patients were included in this study. Forty-three (67.2%) patients had isolated congenital blepharoptosis; 14 (21.9%) had blepharophimosis, ptosis, and epicanthus inversus syndrome (BPES); and 2 (3.1%) had cranial nerve III palsy. Fifty-one (79.7%) patients had no prior blepharoptosis surgery. Lid crease incision and stab incision techniques were utilized for 24 (37.5%) and 40 (62.5%) eyes, respectively. Overall, 21 (32.8%) eyes required reoperation with ePTFE to achieve appropriate eyelid height or contour. Only one patient experienced implant infection, requiring removal of ePTFE sling after a second reoperation. There were no cases of implant exposure or granuloma formation noted during the study period.

CONCLUSION

An ePTFE strip soaked in cefazolin prior to utilization in surgery is a viable material for frontalis suspension surgery, with a lower infectious or inflammatory complication rate than previously reported. However, reoperation rate was still relatively high.

A case of eyelid neuroma with recurrent ptosis

Purpose

We report a rare case of eyelid neuroma, discovered nine years after external levator advancement, presenting with recalcitrant ocular foreign body sensation and pain, persistent corneal epithelial defect, followed by corneal scarring, and ptosis.

Observations

An 85-year-old man with a history of multiple skin cancers presented with left ptosis, epiphora and recalcitrant eye pain. Nine years prior to presentation, he underwent excision of melanoma in situ of the left forehead, followed by simultaneous forehead reconstruction and left external ptosis repair. At presentation, he had left ptosis and left superior corneal scarring. Eversion of the eyelid demonstrated the presence of a nodule at the superior border of the tarsus. The patient underwent simultaneous excisional biopsy of the lesion and posterior ptosis repair by Müller muscle conjunctival resection (MMCR). He experienced postoperative resolution of pain, ptosis and epiphora. Histopathologic examination demonstrated the presence of a foreign body granuloma alongside a neuroma.

Conclusions

This case highlights the importance of thorough eyelid exam in individuals with ocular surface disease. We review herein the pathophysiology and histopathology of eyelid neuroma.

Surgical Outcomes After Frontalis Suspension Using Expanded Polytetrafluoroethylene Sling for Congenital Ptosis

Purpose The purpose of the study is to assess short- and long-term functional outcomes after frontalis suspension using expanded polytetrafluoroethylene (ePTFE) sling for congenital ptosis repair. Methods A retrospective, observational case review was conducted on pediatric patients who underwent frontalis suspension using ePTFE sling from 2008 to 2020. Functional success was assessed by lid height, lid symmetry, and parental satisfaction with the cosmetic outcome. Clinical course and long-term functional outcomes after surgery were assessed. Results Twenty-one cases met the inclusion criteria and were assessed. The follow-up time ranged from 13 months to 11 years (mean: six years). Functional success after one surgery was 62% at early and late postoperative periods. Six of 21 cases (29%) required revisional surgery in the early postoperative period due to undercorrection. Three cases (14%) were complicated by infection and/or granuloma formation. There were no cases of ptosis recurrence in the long term if success was seen in the early postoperative period. Conclusion ePTFE slings remain an excellent option for severe congenital ptosis repair with frontalis sling, demonstrating long-term functional success, with satisfactory lid symmetry and acceptable cosmetic outcome. This is of important consideration in patients younger than three years of age, where autogenous materials may not be recommended. The need for early revisional surgery for undercorrection is not uncommon. The current authors also demonstrate a low but considerable risk for infection and/or granuloma formation.

Temporal-fasciae-complex sheet suspension for correction of severe recurrent blepharoptosis

BACKGROUND

Multiple surgical methods were performed to correct the blepharoptosis. However, the recurrence of blepharoptosis is not uncommon in clinical practice. The Temporal-Fasciae-Complex Sheet (TFC sheet) was an ideal autologous material in correcting the severe blepharoptosis. In the present retrospected study, we introduced our experience in the correction of severe recurrent blepharoptosis with the technique of TFC sheet suspension, and describe the follow-up results to illustrate its effectiveness and practicality.

METHODS

A total of 16 patients (23 eyes) with severe recurrent blepharoptosis were enrolled in this study. All the patients were performed with temporal-fasciae-complex sheet suspension surgeries for revision> 12 months after the primary surgeries by the same treatment group. The margin-to-reflex distance 1 (MRD1), correction effect, and eyelid symmetry were used to evaluate clinical outcomes.

RESULTS

19 eyelids (82.6%) showed good correction results, and 5 eyelids (21.7%) showed fair correction results. The average value of preoperative-MRD1(pre-MRD1) was - 0.17 ± 0.97, and the average value of postoperative-MRD1(post-MRD1) was 4.01 ± 1.24. There was a statistically significant difference between pre-MRD1 and post-MRD1 (p < 0.0001). Good symmetry was observed in 13 patients (81.3%). All patients enrolled were satisfied with the surgical results.

CONCLUSION

The Temporal-Fasciae-Complex Sheet Suspension is an effective and safe method for correcting the recurrent blepharoptosis.

Congenital ptosis repair in children: comparison of frontalis muscle suspension surgery and levator muscle surgery

PURPOSE

Comparing the surgical and refractive outcomes of congenital ptosis repair by different surgical techniques.

METHODS

This longitudinal cohort study reviewed medical records of 101 patients who underwent congenital ptosis repair, from 2006 to 2022 in a single center. Analysis was performed for demographic background, co-morbidities, pre-operative and post-operative ocular examinations and refraction, complications, reoperations, and success rates.

RESULTS

Following exclusion criteria, we remained with 80 patients (103 eyes) who underwent either frontalis muscle suspension surgery (FMS) (55 eyes) or levator muscle surgery (LM) (48 eyes). Patients in the FMS group were younger (mean age of 3.1 vs. 6.0 years, p < 0.001) and had worse pre-operative ocular assessments including prevalence of visual axis involvement, chin-up head position, ptosis severity, and levator muscle function (LF) (p < 0.001). Both groups had a 25% rate of reoperation, however while in the LM group reoperation was required solely due to undercorrection, in the FMS group various indications prompted reoperation. Success rate was higher in the FMS group (87.3% vs. 60.4%, p = 0.002). While pre-operative astigmatism was higher in the LM group (p = 0.019), no significant differences were observed post-operatively. Spherical and spherical equivalent changes over time were significant only in the FMS group (p = 0.010 and p = 0.004, respectively).

CONCLUSIONS

Within our cohort, a higher success rate of congenital ptosis repair was observed among patients who underwent FMS compared to LM, despite similar reoperation rates. In cases of severe ptosis and moderate LF, LM demonstrated a lower-than-anticipated success rate. Astigmatic changes following ptosis repair were not consistent in either group.

Using the "Frontalis-Free Orbital Septum-Complex Flap" in the Correction of Unilateral Congenital Ptosis

Congenital ptosis has deleterious effects on the appearance and vision-related function. Patients need timely and effective treatments. A new surgical practice was performed using the discarded fibrous and thickened orbital septum to prolong the advanced frontalis muscular flap and reduce iatrogenic injuries in the frontalis. A 5-year-old boy with severe unilateral congenital ptosis was enrolled and got satisfactory surgical effects without complication. The "frontalis-free orbital septum-complex flap" is a new and relatively ideal method. The purpose of this paper is to demonstrate this surgical practice and provide a new idea for correcting congenital ptosis with the thickened and fibrotic orbital septum.

Amblyopic astigmatism characteristics and surgical outcomes in younger children with severe congenital ptosis after frontalis suspension surgery

BACKGROUND

To examine the astigmatism characteristics and surgical outcomes in patients with unilateral severe congenital ptosis following frontalis suspension surgery.

METHODS

We included 53 congenital ptosis patients who underwent frontalis suspension surgery in Hunan Children's Hospital. Each patient underwent a refractive examination before and after surgery to assess astigmatism. We also evaluated the effects and complications associated with the procedure.

RESULTS

Degree of astigmatism in ptotic and fellow eyes was - 1.45 ± 0.59 D and - 0.66 ± 0.51 D before surgery. Ratio of severe astigmatism in ptotic and fellow eyes was 51.3 and 12.8%. The fellow eyes presented with with-the-rule astigmatism (WR; 71.8%) and against-the-rule astigmatism (AR; 20.5%) types, with no cases of oblique astigmatism (OA). Ptotic eyes demonstrated higher frequencies of AR (59.0%) and OA (10.2%) than did fellow eyes. Furthermore, the former showed increased astigmatism, followed by a gradual decrease at the 6-month, before significantly decreasing at the 1-year postoperatively. The ratio of postoperative AR and OA astigmatism cases in ptotic eyes decreased to 35.9 and 7.7% 1 month postoperatively. However, there was a postoperative increase in the WR ratio from 30.8 to 56.4% after 1 month. Kaplan-Meier survival analysis showed a success rate of 81.4% at 6 months and 62.9% at 12 months which was influenced by the following complications: suture reaction, epithelial keratopathy, infection and granuloma, lid lag, and recurrence.

CONCLUSION

Monocular congenital ptosis could develop severe astigmatism and higher frequency of AR or OA, early surgery may ameliorate astigmatic amblyopia.

Survey of ptosis practice patterns among surgeons in Asia Pacific Society of Ophthalmic Plastic and Reconstructive Surgery (APSOPRS)

OBJECTIVE

To characterize the preferred ptosis practice patterns and variations among oculoplastic surgeons in the Asia-Pacific region.

METHODS

A web-based questionnaire was sent to both members and non-members registered under the Asia Pacific Society of Ophthalmic Plastic and Reconstructive Surgery (APSOPRS)'s email database. The survey included preoperative testing practices, surgical preferences for adult aponeurotic and congenital ptosis, various surgical techniques (anterior and posterior approach ptosis procedures, and frontalis sling procedures) and postoperative practices.

RESULTS

A total of 386 survey invitations were sent. There was a response rate of 68.7% from respondents from 20 countries in the Asia-Pacific region. There was variation in the preoperative evaluation and management of ptosis. Anterior approach ptosis surgery (96.6%) and frontalis sling procedures (86.8%) were performed by more surgeons than posterior approach ptosis surgery (47.2%). There was a deviation from the traditional frontalis sling procedures for patients with poor levator function.

CONCLUSIONS

Our survey results provide insight into the variation in the assessment and management of ptosis amongst oculoplastic surgeons in the Asia-Pacific region. It also demonstrates some differences between practice patterns in Asia-Pacific and America.

Management of Marcus Gunn jaw wink syndrome with tarsofrontalis sling vis a vis levator excision and frontalis sling: a comparative study

PURPOSE

To compare the results between tarsofrontalis sling (TFS) and levator palpebrae superioris (LPS) excision with TFS in cases of ptosis with Marcus Gunn jaw winking syndrome (MGJWS).

METHOD

A retrospective review of records of all patients undergoing either TFS (group A) or LPS excision along with TFS (group B) in cases of ptosis with MGJWS was done over the past 10 years and their results were compared.

RESULTS

The study included 73 patients (75 eyes). There were 36 patients (36 eyes) in group A and 37 patients (39 eyes) in group B. There was a significant reduction in the excursion due to MGJWS from 4.7 ± 1.49 to 1.91 ± 1.04 mm in group A (p = .001) and 4.65 ± 1.34 to 1.79 ± 0.98 mm in group B (p < .05). The reduction in excursion due to MGJWS and lagophthalmos were comparable in both groups. The mean follow-up in group A was 5.62 ± 6.94 (Range: 1-24) months and group B was 19.15 ± 29.16 (Range: 1-96) months (p = .01).

CONCLUSION

Both TFS and LPS excision with TFS is equally effective in dampening the eyelid excursion in MGJWS. Tarsofrontalis sling is a safe, easy and effective technique for MGJWS with lesser complication.

Frontalis suspension by a minimally invasive "harvesting-stripping technique" for congenital blepharoptosis in children under 3-years-old

PURPOSE

To describe a minimally-invasive "harvesting-stripping technique" on a small segment of autogenous fascia lata (AFL) in small children with severe blepharoptosis under 3-years-old.

METHODS

A single-surgeon, uncontrolled surgical trial was designed for 25 eyelids of 18 small children (5 girls, 13 boys) with severe blepharoptosis. Single- and short-skin incisions (2-cm) were made on the thigh and a final 3X0.6-cm or 3.5X1-cm AFL segment was excised according to the ptosis laterality. The surface area of the harvested AFL was calculated and dissected for a final 9-cmX2-mm-long fascial strip for each eye. Functional and aesthetic outcomes of the upper eyelids were evaluated and the feasibility, effectivity and advantages of this novel approach in younger patients were assessed.

RESULTS

The mean age was 28.3 months (17-35) with a mean follow-up of 34.3 months (6-96). All eyelids achieved good or excellent functional and aesthetic results (except one), with no peri- or post-operative severe complications such as haemorrhage, wound infection, hypertrophied thigh scar, muscle prolapses, eyelid contour abnormalities, ptosis recurrence or overcorrection.

CONCLUSIONS

"Harvesting-stripping technique" with the AFL may be an alternative approach to correct severe upper blepharoptosis in small children under 3-years-old, which offers various benefits over conventional methods with non-autogenous materials.

The versatility of tensor fascia lata allografts for soft tissue reconstruction

The purpose of this retrospective study was to introduce our successful use of tensor fascia lata allograft to reconstruct various soft tissue defects. Since May 2021, we have applied tensor fascia lata allografts in eight cases. A frozen type of fascia of 0.6 mm thickness was used in all cases, and allografts were covered by vascularized soft tissue. We used tensor fascia lata allograft in eight cases to cover the infected wounds, donor site closure, and pedicle protections. These were abdominal wall and back reconstructions following rectus muscle and latissimus dorsi muscle harvest, coverage of infected spine wound after posterior fusion, pressure ulcer reconstruction, and pedicle protection of free and pedicle flaps. The follow-up periods were from one to 14 months. None of the cases showed wound problems after initial reconstruction using tensor fascia lata allografts. Tensor fascia lata allograft could be an excellent cost-effective surgical option comparable to autologous tissue grafts. Level of evidence: IV.

Maximal levator resection versus Gore-Tex® sling for congenital blepharoptosis with poor levator function

BACKGROUND:

Treating congenital blepharoptosis is often mandatory to clear the visual access and avoid amblyopia; however, when the levator function is poor, achieving a satisfactory long-term outcome is challenging. This study aimed to compare the outcomes of maximal levator resection (MLR) with those of frontalis suspension (FS) using Gore-Tex ^®, in the treatment of congenital blepharoptosis with poor levator function.

PATIENTS AND METHODS:

The study included 102 eyelids of 66 patients of mean age 4.3 ± 1.6 standard deviation (SD) years, randomly divided into two groups (51 eyes each). Group A: FS using Gore-Tex ^®, Group B: MLR. Postoperative outcomes were evaluated at 1, 6 and 12 months. Patients' ophthalmic examination including margin-reflex distance (MRD1) before and after surgery and postoperative complications were recorded.

RESULTS:

At the end of the follow-up, the mean MRD1 increased from 0.3 ± 0.7 SD mm in Group A, 0.4 ± 0.8 SD mm in Group B preoperatively, to 2.7 ± 0.5 SD mm and 2.9 ± 0.7 SD mm, respectively (P < 0.001 in both groups). Results of Group B were significantly higher than Group A (P = 0.047). Success was achieved in 77 eyelids (75.4%), distributed as follows: 36 eyelids (70.6%) in Group A, and 41 eyelids (80.1%) in Group B. The total recurrence rate was 6.9% (seven eyes), while other complications were recorded in 23 eyes (22.5%).

CONCLUSION:

MLR, compared to FS with Gore-Tex^® sling, can be a more efficient surgical option to correct congenital blepharoptosis with poor levator excursion. Prominent postoperative lagophthalmos warrants close ocular surface observation in early follow-up weeks.

Modified Maximal Levator Palpebrae Superioris Shortening in Correcting Congenital Severe Ptosis in Children

OBJECTIVE

This study aims to evaluate the clinical effect of modified maximal levator palpebrae superioris shortening method for severe congenital ptosis.

METHODS

A retrospective case series was performed including 66 eyes from 62 patients who underwent modified maximal levator palpebrae superioris shortening surgery to treat severe congenital ptosis between February 2015 and November 2018. Preoperative and postoperative margin reflex distance 1 and levator muscle function were recorded. The surgical results were graded as good, satisfied, and poor for functional and cosmetic improvement of the eyelids, and the incidence of complications was also documented.

RESULTS

The mean patient age at the time of surgery was 4.6 ± 1.8 years (2-9 years), and the mean follow-up time was 36.3 ± 14.1 (12-55 months). A mean significant improvement in margin reflex distance 1 and levator function after operation was noted (P < 0.01). The eyelid height and symmetry were satisfied in 59 patients, with success rate of 95.2%. For the patients in the levator function (≤2 mm) group, the success rate was 87.5%. Moreover, the levator function (≤2 mm) group had a higher rate of poor results than levator function (2-4 mm) group (12.5% vs 2.2%). Overcorrection (6.5%) and eyelid fold deformity (11.3%) were the most frequent postoperative complications.

CONCLUSION

Modified maximal levator palpebrae superioris shortening was effective and endurable in the treatment of severe congenital ptosis with poor levator function, including in patients whose levator function was less than 2 mm.

Unilateral Levator Aponeurosis Excision for Marcus Gunn Syndrome and Risk Factors of Residual Jaw Winking

Purpose

To investigate the association of ptosis, levator, and jaw winking in Marcus Gunn jaw-winking synkinesis (MGJWS), and the risk factor of preservation and outcomes of the unilateral levator excision and frontalis suspension.

Methods

Clinical features of MGJWS case series from 2011 to 2018 were retrospectively reviewed. Association between jaw winking and ptosis/levator function was statistically analyzed. The patients underwent unilateral levator excision and frontalis suspension using silicone rod or autogenous fascia lata. Clinical outcomes were evaluated in operated patients and the independent risk factors of residual jaw winking were investigated after a long follow-up.

Results

There were 42 MGJWS patients in 2011 to 2018, accounting for 2.87% of all congenital blepharoptosis. 80% of mild jaw winking was accompanied with mild ptosis and fair levator function, and moderate-to-severe jaw winking was often accompanied with moderate-to-severe ptosis and poor levator function (P < 0.05). Ptosis showed a strong association with excursion of jaw winking (R = 0.785, P < 0.01). Jaw winking was resolved in all 34 operated patients with good correction of ptosis. Severity of jaw winking is an independent risk factor for the residual synkinesis after surgery. Severe preoperative jaw winking had an 18.05 times increased risk of postoperative residual synkinesis compared with moderate jaw winking (P < 0.05).

Conclusions

In MGJWS eyelid excursion of jaw winking has a direct correlation with ptosis and dysfunction of levator muscle. Unilateral levator aponeurosis excision and frontalis suspension is an efficient approach for MGJWS. Severe jaw winking is a risk factor of residual eyelid synkinesis after surgery.

Surgical treatment of unilateral severe simple congenital ptosis

Unilateral congenital ptosis with poor levator function of ≤4 mm continues to be a difficult challenge for the oculoplastic surgeon. Surgical correction can be accomplished with unilateral frontalis suspension, maximal levator resection, or bilateral frontalis suspension with or without levator muscle excision of the normal eyelid. Bilateral frontalis suspension was proposed by Beard and Callahan to overcome the challenge of postoperative asymmetry, allowing symmetrical lagophthalmos on downgaze, postoperatively. However, most surgeons and patients prefer unilateral correction on the abnormal eyelid either with a frontalis suspension or maximal levator resection. Frontalis suspension may be performed through the various surgical techniques using different autogenous or exogenous materials. Autogenous fascia lata is considered the material of choice with low recurrence rates but carries the drawbacks of the difficulty of harvesting and postoperative morbidity from the second surgical site. Recent reports have suggested that maximal levator resection provides improved cosmesis, a more natural contour, and avoids brow scars. Although both treatments have shown to have similar success rates, there is much debate about what the most favorable method for treating severe unilateral ptosis. We review the literature on the various surgical treatments for unilateral severe congenital ptosis, including the rationale, advantages and disadvantages of each technique.

Frontalis suspension using autogenous temporal fascia by Fox technique

INTRODUCTION

Severe ptosis of more than 4mm with poor levator function of less than 4mm is treated via the frontalis muscle suspension technique using autogenous temporal fascia.

TECHNICAL NOTE

The surgery was performed under general anaesthesia. The eyelid crease was incised and the tarsus exposed. An incision centered on the mid-pupillary level was then made just above the eyebrow with exposure of the frontalis muscle. The temporal fascia strip was sutured to the tarsus at three points. Every free end of the strip was then slid through the adjacent forehead subcutaneous tunnel to emerge together through the medial forehead incision. The eyelid crease was re-formed by suturing the skin with the graft.

DISCUSSION

Frontalis suspension using autologous material is a harmless procedure, which does not alter the upper eyelid structures. It is an effective procedure in the long-term.

3D printing for low cost, rapid prototyping of eyelid crutches

Blepharoptosis or ptosis is a common and potentially debilitating clinical problem. Long-term surgical treatment for ptosis caused by progressive myopathies can be challenging due to potential recurrence and complications associated with facial muscle weakness. When surgical treatment is no longer effective, an eyelid crutch can be used as an alternative intervention. This report demonstrates how 3D printing was used to rapidly design, prototype, and manufacture new custom-fit eyelid crutches at a low cost.

Analysis of the causes of recurrence after frontalis suspension using silicone rods for congenital ptosis

Background

Silicone rod is a commonly used synthetic suspension material in frontalis suspension surgery to correct blepharoptosis. The most challenging problem and a decisive drawback of the use of silicone rod is a considerable rate of ptosis recurrence after surgery. We examined patients with recurred ptosis and assessed the physical and micromorphological properties of implanted silicone rods to determine the causative mechanisms of recurred ptosis after frontalis suspension using silicone rod.

Methods

This is a prospective observational case series of 22 pediatric patients with recurred ptosis after frontalis suspension using silicone rods for congenital ptosis. Implanted silicone rods were observed and removed during the operation for correction of recurred ptosis. The removed silicone rods were physically and micromorphologically evaluated to determine the cause of recurrence.

Results

Pretarsal fixation positions migrated upward, whereas suprabrow fixation positions migrated downward during ptosis recurrence. The breaking strength of implanted silicone rods was reduced by approximately 50% during 3 years. Cracks, debris, and loss of homogenous structure with disintegration were observed on scanning electron micrographs of implanted silicone rods in patients with recurred ptosis. Preoperative severe degree of ptosis also contributed to recurred ptosis.

Conclusions

Recurrence of ptosis after frontalis suspension using silicone rod was associated with physical changes of implanted silicone rods, including positional migration, weakened tensile strength, and micromorphological changes in combination with patients’ characteristics.