Surgical Treatment in Post-Stroke Spastic Hands: A Systematic Review

Background: For more than two decades, the surgical treatment of post-stroke spastic hands has been displaced by botulinum toxin therapy and is currently underutilized. Objectives: This article aimed to assess the potential of surgery for treating a post-stroke spastic upper extremity through a systematic review of the literature on surgical approaches that are adopted in different profiles of patients and on their outcomes and complications. Methods: Medline PubMed, Web of Science, SCOPUS, and Cochrane Library databases were searched for observational and experimental studies published in English up to November 2022. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) system. Results: The search retrieved 501 abstracts, and 22 articles were finally selected. The GRADE-assessed quality of evidence was low or very low. The results of the reviewed studies suggest that surgery is a useful, safe, and enduring treatment for post-stroke spastic upper extremities, although most studied patients were candidates for hygienic improvements alone. Patients usually require an individualized combination of techniques. Over the past ten years, interest has grown in procedures that act on the peripheral nerve. Conclusions: Despite the lack of comparative studies on the effectiveness, safety, and cost of the treatments, botulinum toxin has displaced surgery for these patients. Studies to date have found surgery to be an effective and safe approach, but their weak design yields only poor-quality evidence, and clinical trials are warranted to compare these treatment options.


Introduction
Stroke is the principal cause of permanent disability among adults [1].More than one-third of stroke patients develop spasticity that requires lifelong medical treatment and increases their dependence on others for daily living activities [2,3].Upper extremity spasticity frequently results from upper motor neuron damage that is caused by stroke, traumatic brain injury, multiple sclerosis, spinal cord injury, or cerebral palsy [3].The spastic upper extremity loses the functional position of the hand in space.Patients often have a deformity with internal rotation and shoulder adduction, elbow flexion, forearm pronation, wrist flexion, thumb adduction in palm, and/or flexion of triphalangeal fingers.The deformity can have functional, cosmetic, and/or hygienic repercussions, depending on its intensity [4].
Currently, the first-choice treatment for localized spasticity is the intramuscular injection of botulinum toxin A [5][6][7], although this approach has some drawbacks.Thus, the injection can produce discomfort, the result persists for a maximum of only 3-4 months [8], and it is not useful for muscle or soft tissue contractures [9].Around 30 years ago, patients with upper extremity spasticity after a first motor neuron injury were treated by surgery, but this option is now rarely considered in spasticity management protocols [7,10] and has been replaced by botulinum toxin therapy.However, no studies have compared the outcomes of these treatment modalities.
Various surgical procedures can be used to optimize function, reduce pain, and improve hygiene and esthetics in spastic upper extremities [11].For instance, deformities can be corrected with single-event multilevel surgery, combining releases and elongations of soft tissues, tendon transfers, and joint stabilization procedures [12], or by centering on the nerve as the vehicle of spasticity.In this regard, different authors have proposed hyponeurotization, hyperselective neurectomy [13], and even rhizotomy of the C7 root of the affected extremity, followed by contralateral C7 nerve root transfer [14][15][16], to release the spasticity of the flexor musculature and strengthen weak extensor muscles.
Despite evidence of the long-term effectiveness of surgery in improving the function and hygiene of spastic upper extremities [12,17,18], it is now little used for this purpose [10], hampering evaluation of its true therapeutic potential and the risk of complications.We undertook a systematic review of the literature on surgical approaches that have been adopted in different profiles of patients and on their outcomes and complications, evaluating the quality of the published evidence.The aim was to guide clinical practice and to summarize available evidence for post-stroke patients with a spastic upper extremity who are interested in treatments other than botulinum toxin.

Material and Methods
This systemic review and its reporting followed the 2020 Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines [19] (Table 1).The review protocol was prospectively registered in PROSPERO with ID CRD42022366686 (www.crd.york.ac.uk/PROSPERO, accessed on 15 November 2022).PICO for the research question: Which surgical approaches to adult patients with post-stroke spasticity of the upper extremity are effective in terms of improving their function, care, and quality of life?

Patient
Adult patients with post-stroke spasticity of upper extremity.

Intervention Surgical treatment of spastic upper extremity
Comparator Untreated patients and/or (when available) patients treated with botulin toxin.

Data Sources and Searches
The Medline PubMed, Web of Science, SCOPUS, and Cochrane Library databases were searched for studies up to November 2022 in accordance with the above protocol, using the following search strategy equation: (hand OR wrist OR thumb) AND (paralysis OR spastic* OR deformity* OR palsy) AND (transfer* OR surgery OR surgical OR neurectomy) AND (stroke OR cerebrovascular OR CVA).The reference lists of selected studies were also examined for relevant articles in a reverse search.Rayyan Systematic Review Screening Software (https://www.rayyan.ai/,accessed on 16 May 2022) was employed to identify and eliminate duplicates.

Study Selection
The titles and abstracts of retrieved articles were independently screened by two reviewers (AGS, PHO) to select publications meeting the review's eligibility criteria.A third researcher (PHC) was consulted to resolve cases of disagreement.Inclusion criteria were as follows: observational or experimental design, from case series to clinical trials; evaluation of surgical treatment of post-stroke spastic upper extremity in patients of any age; and publication in English, regardless of the country of origin.Exclusion criteria were review articles, expert opinions, single case reports, exclusive focus on shoulder, cadaver research, qualitative research, and non-availability of whole text.

Data Extraction and Quality Assessment
The full texts of articles that were selected in the initial screening were reviewed independently by AGS and PHO to decide on their suitability for inclusion and to carry out data extraction and quality assessment procedures.PHC was consulted in cases of disagreement.Articles traced in the reverse search underwent the same process.Data were extracted on the author(s), year of publication, geographic origin, study type, sample size, baseline patient profile and diagnosis, surgical procedure, sample distribution, method of evaluation, efficacy and safety outcomes, and follow-up period.
The Grading of Recommendations Assessment, Development, and Evaluations (GRADE) was used to evaluate the quality of the evidence as high, moderate, low, or very low [20], and the Cochrane Collaboration tool served to assess the risk of bias.It was not possible to perform a meta-analysis due to the heterogeneity of patient samples, procedures, and outcomes.

Results
The search initially retrieved 501 abstracts (after removal of duplicates), 34 of which met the eligibility criteria.After reading the full texts of the studies, 19 were excluded, but 7 studies were added from the reverse search, leaving a total of 22 studies in the systematic review.Table 2 provides summarized information on the selected studies.Figure 1 depicts a flowchart of the review process.

Patient Profile
The studies reported on a total of 965 upper extremities in 939 patients.The patient samples were heterogenous in all except two studies [37,38], comprising not only patients with stroke but also those with other etiologies of upper extremity spasticity, including traumatic brain injury and cerebral palsy.Stroke sequelae in the upper extremity was observed in 355 (37.80%) of the patients.The goal of surgery was exclusively hygienic in ten Sixteen studies were retrospective case series [12,17,18,[21][22][23][24][26][27][28][29][30][31][32][33]37], two were single-center [25] or multi-center [38] retrospective cohort studies, three were prospective case series [34][35][36], and one was a randomized controlled trial [16].Only three studies included a comparative group, formed by patients who were treated with rehabilitation in two [16,38] and those undergoing a different surgical technique in the third [25].No studies compared surgery and botulinum toxin treatment.The main sources of bias were a small sample size, a short follow-up period, the absence of a control group, a heterogeneous patient sample, and the partly subjective evaluation of outcomes (Table 3).The mean postoperative follow-up was 21.22 months (range, 6-47.7 months).The follow-up period was one year or shorter in eight (36.36%) of the studies.

Patient Profile
The studies reported on a total of 965 upper extremities in 939 patients.The patient samples were heterogenous in all except two studies [37,38], comprising not only patients with stroke but also those with other etiologies of upper extremity spasticity, including traumatic brain injury and cerebral palsy.Stroke sequelae in the upper extremity was observed in 355 (37.80%) of the patients.The goal of surgery was exclusively hygienic in ten studies [12,[16][17][18]24,25,[31][32][33], which included a total of 287 hands in 270 patients (i.e., 29.74% of hands in all reviewed studies and 28.75% of patients).Only two articles studied candidates for functional surgery [26,29], reporting on a total of 56 patients (5.96% of patients in reviewed studies).In the remaining studies, the patient sample was mixed, with functional and nonfunctional hands or hands of unspecified status [21,28,30,[34][35][36][37][38]41].None of the reviewed studies stratified their outcomes according to the etiology of the upper extremity spasticity or the patient profile.Overall, 690 males (73.48%) and 249 females (26.51%) were treated.Inadequate data are available to calculate the mean age of the global series, complicated by differences in the etiology of the patients' spasticity; however, the mean age was <50 years in 16 of the 22 studies.Figure 3 depicts the geographical origin of the reviewed articles.
however, the mean age was <50 years in 16 of the 22 studies.Figure 3 depicts the geographical origin of the reviewed articles.

Types of Surgery
The most frequently reported surgical approaches (Table 4) were the transfer of Superficialis-to-Profundus (STP) flexors, muscle-tendon releases, wrist arthrodesis, and peripheral neurectomies.Contralateral C7 nerve root transfer was described in only three studies [16,37,38].

Types of Surgery
The most frequently reported surgical approaches (Table 4) were the transfer of Superficialis-to-Profundus (STP) flexors, muscle-tendon releases, wrist arthrodesis, and peripheral neurectomies.Contralateral C7 nerve root transfer was described in only three studies [16,37,38].Types of surgery performed in the reviewed studies.* Upper extremities treated in each study.** Total = 710 upper extremities.

Effectiveness/Efficacy and Safety
Table 5 displays the different evaluations of outcomes, which can be classified as very good, especially for hygiene improvement and pain reduction, with patient satisfaction rates ranging between 65 [28] and 100% [18].Hygiene improvement was reported in 87.5 [21]-100% of operated patients [17,18,22,24,33,42].Kwak et al. [28] described a reduction in the visual analog scale (VAS) score for pain in a spastic upper extremity from 5.85 pre-surgery to 2.28 post-surgery.Gatin et al. [32] reported on 63 patients with a nonfunctional spastic hand who obtained post-surgical Goal Attainment Scaling (GAS) scores of 1.1 for analgesia, 1.0 for cosmetic appearance, and 1.3 for hygienic conditions, indicating that the outcomes were better or much better than expected.Gschwind et al. [12] studied 38 patients with severe spasticity and nonfunctional upper extremities and found a significant improvement in the Carer Burden Score at three months post-surgery.
The only reported complications of peripheral nerve surgery have been mild, although two [25,36] of the seven studies did not provide any data on adverse effects.Paresthesia and dysesthesia were reported in less than 10% of peripheral neurectomies [26,28], and no severe or disabling sequelae were observed after crossed C7 nerve transfer, when the most common complication was pain in the shoulder, back, or extremity at one-month post-surgery (in 58%) that usually disappeared at six months [38].In donor extremities, fatigue was reported in 41.66%, hand numbness in 44.44%, elbow weakness in 42.66%, wrist extension weakness in 44.44%, and sensory attenuation in 44.44% [16].

Discussion
We present the first systematic review of studies on post-stroke spastic upper extremities, based on a selection of 22 articles published up to 2022.Systematic reviews and meta-analyses have been performed on the efficacy of botulinum toxin type A in these patients [43][44][45] but not on the efficacy of surgery.
In 2021, Hashemi et al. published [46] a systematic review on the efficacy of surgery in treating spastic upper extremeties of different etiologies, and some study samples contained no patients with stroke (neither CVA nor Stroke was a search term).The larger number of items that were retrieved is attributable to their inclusion of publications in French or Farsi, review articles and updates, and series of patients whose shoulder alone was treated.Outcomes were analyzed as a function of anatomical site (i.e., shoulder, elbow, wrist, hand, or fingers) and main surgical procedure; however, no study included contralateral C7 root transfer, probably the most innovative surgical approach to date.The authors were unable to draw specific conclusions about the efficacy of surgery because of the differences among studies in patient samples and procedures.The same problem of heterogenous populations and the failure to stratify outcomes by the cause of spasticity also limited earlier systematic reviews on thumb-in-palm deformity by Smeulders et al. in 2005 [47] and on peripheral neurectomy by Yong et al. in 2018 [48].All cases of upper extremity spastic paresis result from upper motor neuron syndrome, but treatment decisions must take account of the etiology and the age and profile of patients [49].The surgical goal differs between patients whose hands have functional possibilities and those with more severe upper extremity spasticity and nonfunctional hands.Surgical endpoints for the latter group of patients are solely related to hygiene, esthetics, or comfort, and the same evaluation methods cannot be applied.In this regard, Feng et al. (2021) reduced the variability in assessment methods by focusing on quality-of-life changes and patient-reported outcomes [38].The follow-up period varied among the studies but was generally too short (≤12 months) to confirm the longer-term efficacy of surgery.Although it impairs their prehension capacity, it is performed in patients with stroke sequelae with no expectation of a functional hand from surgery.It is associated with fewer complications in comparison to flexor-origin release, because it requires lesser dissection, and it is less laborious and faster than the selective elongation of all flexor tendons.
Published outcomes have been very good, with an improvement in hygienic conditions in 100% of patients and satisfaction rates of 87 [39]-100% [17,18].Pain relief was not always evaluated, but the intervention was described as having a beneficial effect against pain in most cases [18,33], and Peraut et al. [33] observed functional improvement on the House Scale in 7 out of 26 patients.
Published complications include over-correction, incomplete correction, deformity by the unmasking of intrinsic spasticity, and partial baseline deformity recurrence.No systemic complications have been reported.Some authors [18,25] observed no complications, while Peraut et al., 2018 [33], reported postoperative deformities through the "unmasking" of intrinsic spasticity in 38.46% and swan neck finger deformities in 23.07%.Recurrences of the deformity (in 12.5%) were only observed by Braun et al. [21].A selective fractioned elongation of wrist and finger flexors or flexor-pronator-origin slide can be performed to improve function in patients with deformity due to extrinsic flexor spasticity who retain volitive control and sensitivity [50].These procedures may be combined with tendon transfers to improve wrist extension, mainly from the flexor carpi ulnaris (FCU) to the Extensor Carpi Radialis Longus (ECRL), but only Gatin et al. [32] described this approach for stroke sequelae.Transfers for extension in infantile cerebral palsy involves a risk of reverse postoperative deformities and alteration of the post-prehension release phase [51], and this possibility should also be considered in post-stroke patients.
Very good outcomes have been reported for these techniques, including significant and consistent improvements in rest position, spasticity, pain, and function [32,35].Function improvement was achieved in >90% of patients, with volitive control after either selective fractioned tendon elongation [42] or flexor-origin release [23].
Although AlHakeem et al. described an improvement in gait function in 2020 [34], it was only observed in three patients, and it would be due to the change in positioning of the upper extremity rather than to the surgical procedure per se.
The rate (<30%) and types of local complications [32] that are observed for flexororigin release were similar to those reported for STP, including prehension weakness (9 [42]-20% [35]), over-correction, incomplete correction, deformity by "unmasking" of intrinsic spasticity (12 [30]-30% [42]), and partial recurrence of baseline deformity (22% [30]).Some of these complications may be reduced with the application of surgery under WALANT (Wide-Awake Local Anesthesia No Tourniquet) versus general anesthesia, as recently proposed by Kumar and Ho [52], because it permits the active collaboration and mobility of patients and a more precise calibration, customizing each fractional tendon elongation in real time.The authors observed no under-or over-corrections when adopting this approach.

Wrist Arthrodesis
All reports on post-stroke wrist arthrodesis have involved patients with nonfunctional hands who were treated for hygiene improvement alone [12,17,24,25,27,31].In spastic patients with no volitive hand control, wrist arthrodesis is more reproducible and longlasting in comparison to isolated soft tissue procedures [24].First-row carpectomy is often necessary to place the wrist in a neutral or slightly extended position [41], and other procedures are frequently associated, including STP, carpal tunnel release, thumb-long flexor elongation, and sometimes ulnar nerve motor branch neurectomy to treat intrinsic spasticity [17,52].
Again, published results are very good and report hygienic improvement [17,24,31,53], wrist flexion correction of between 66 • [31] and 85 • [24], and reduced carer burden [12] in virtually all patients.A screwed compression or neutralization plate with autograft was used as an internal fixation method by all authors except for Rayyan and Young (1999) [24], who employed a structural iliac graft.
Only local complications have been reported, although these affected one-third of the patients studied by Pomerance and Keenan (1996) [17].The procedure-specific complication is non-consolidated pseudoarthrosis; however, although a nonunion rate of 13% was observed by Pomerance and Keenan in 1996 [17], more recent articles have not reported this complication.Once more, the procedure can be complicated by the unmasking of intrinsic spasticity and swan neck finger deformity [31,44].

Selective Peripheral Neurotomy
In 1913, partial or selective neurectomy of specific motor nerve fascicles was proposed by Stoffel [54] to improve function in patients with upper extremity spasticity, and the treatment gained in popularity after the publication of the study by Brunelli and Brunelli [55].The authors initially resected 50% of nerve branches at their muscle insertion points; however, observations of spasticity recurrence due to the "adoption" phenomenon [55] led them to resect 80% of branches or carry out a second neurectomy some months after the first intervention.This procedure has recently been refined [13,56], and partial neurectomy is now performed at the insertion point of each muscle motor branch.
Neurectomy is most frequently performed in the ulnar nerve motor branch [12,25,27], median nerve recurrent branch [25,28], musculocutaneous nerve [26,36], and the nerves of Pronator Teres (PT), Flexor carpi radialis (FCR), and FCU [36].A pre-surgical anesthetic block of peripheral nerves allows for differentiation between spasticity and contracture.The published neurectomy outcomes have been very good, obtaining a significant decrease in spasticity on the modified Ashworth scale, with mean patient satisfaction rates ranging between 64.09 [28] and 83% [36].Virtually no complications are reported, except for some cases of surgical wound infection.There has been little research on "intrinsic minus" hand deformities, and only Facca et al. [27] described incomplete corrections, observed in around half of patients.Despite expectations related to the adoption phenomenon [55], authors observed no recurrences [28] or only a slight relapse in spasticity, and improvements remained statistically significant at the final follow-up evaluation [26,28,36].

Contralateral C7 Nerve Transfer
Cervical nerve root transfer from the contralateral side has been used to repair brachial plexus root avulsion since 1986 [57].Variants of this technique include the interposition of a free nerve graft [57], passing the nerve graft through the retropharyngeal and prespinal space instead of the subcutaneous tunnel on the anterior surface of the neck and chest [58], or direct coaptation of the transfer without nerve graft interposition [59].Different receptor nerves have been utilized in C7 transfer, and Xu et al. were the first to employ the C7 root of the affected side as receptor in a child with spastic paralysis [14].In 2018, the first clinical trial of contralateral C7 transfer obtained significantly better results compared with rehabilitation [16] in the reduction in spasticity on the modified Ashworth scale and the improvement in function on the Fugl-Maier scale.Functional magnetic resonance imaging (f-MRI) was used to verify the activation of the ipsilateral brain hemisphere with mobility of the affected arm.In 2021, Feng et al. published the largest contralateral C7 transfer trial to date [38] in more than 400 patients, including 168 who underwent the intervention.There was a predominance of patients with stroke in both the surgery and rehabilitation groups, and contralateral C7 transfer achieved significant improvements in spasticity and function (Fugl-Maier scale).The published complications were all mild, including slight weakness, fatigue, soreness, and discomfort on the unaffected side, and they disappeared at 3-6 months post-surgery [16,37,38].However, this research was conducted in the specific socio-cultural setting of Asia.It may not be so easy to convince patients in many Western settings to transfer nerve elements from the unaffected extremity, on which they may depend for a certain level of function and independence.For this reason, the proposal to transfer these elements from the affected extremity (as both receptor and donor) is of particular interest, avoiding any risk to the healthy arm.
Nerve transfer is an innovative surgical approach to upper extremity paralysis that is well documented in patients with brachial plexus sequalae and is under evaluation for tetraplegic patients; however, it has not yet been described for spastic upper extremities.Waxweiler et al. [60] and Jaloux et al. [61] combined neurectomy with nerve transfer, performing a partial nerve transfer from spastic muscles (elbow flexor, FCR, and PT) to "recipient" motor branches of weak wrist and finger extensor muscles (ECRL, Extensor Carpi Radialis Brevis).The aim was to reduce the spasticity of the former and simultaneously activate the latter.
In general, surgery has proved to be an effective treatment option that offers longlasting results with a low rate of major complications.This raises questions about the status of botulinum toxin as a first-line treatment for regional post-stroke spasticity of the upper extremity [43], given the absence of comparative data on the effectiveness, safety, and economic cost of the two approaches.Beutel et al. [10] investigated upper extremity reconstructive surgery in patients with stroke or TBI in the USA National Inpatient Sample (NIS) database between 2001 and 2012.They reported that 80% of 730,000 new cases of stroke/year survived the acute episode, 76% of the survivors developed spasticity, and 50% of these spastic patients could benefit from surgery [62].Nevertheless, only 2132 patients underwent surgery during the 12-year study period, i.e., less than 1% of the suitable candidates for surgery, indicating a marked underutilization of upper extremity reconstructive surgery in this patient population.

Other Therapies
The assessment of the therapeutic potential of surgery does not imply an opposition to treatment with toxin or other conservative therapies.The multiple nonsurgical options that are available for the rehabilitation of upper extremity spasticity should be integrated in a multidisciplinary approach to optimize function and prevent deformity in post-stroke patients.Thus, control of baseline muscle tone can be improved by medication, botulinum toxin injection, and chemodenervation, allowing therapists to maximize muscle strengthening, maintain joint integrity, and increase task-specific training [63].Orthotics can reduce deformity and improve function [64], and radial extracorporeal shock wave therapy (RESWT) has also been proposed for spasticity reduction [65].Megna et al. studied post-stroke patients with spastic upper extremities and observed a greater spasticity reduction (modified Asworth scale) in patients who were treated with a combination of physical therapy, botulinum toxin injection, and RESWT than in those receiving physiotherapy and botulinum toxin alone [66].Promisingly, new technologies are developing novel tools for rehabilitation of the spastic hand, notably robotic therapy [67], virtual reality [68], transcranial magnetic stimulation [69], and brain-computer interface systems [70].

Strengths and Limitations of the Review
The main limitation of this review is the poor quality of the scientific evidence that is offered by the studies, largely due to their design and the heterogeneity of patient samples.Furthermore, inadequate information is provided to enable the stratification of types of patients and procedures for comparison, and studies differ in their outcome evaluation methods, which are sometimes highly subjective.Finally, follow-up periods have been too short to evaluate outcomes and complications over the longer term.It was not feasible to search the gray literature, which might possibly have caused some publication bias, and it was not possible to perform a meta-analysis due to the heterogeneity of patient profiles and evaluated outcomes.Strengths of our systematic review include its compliance with the rigorous PRISMA guidelines and its synthesis of the scant available information on an issue of major clinical relevance.

Conclusions
The results of this review suggest that surgery is a useful, safe, and durable treatment option for post-stroke spastic upper extremities, although most studied patients were only candidates for hygienic improvement.Patients often require an individualized combination of techniques, and there has been renewed interest over the past ten years in procedures that act on the nerve.However, the reviewed studies provide only weak evidence due to their design and heterogeneous patient populations.There is a need for clinical trials to compare surgery and botulinum toxin in the treatment of these patients.The aim is not to exclude one of these approaches but rather to explore how their potential and indications might be integrated within a multidisciplinary treatment protocol in a complementary manner.

Figure 1 .
Figure 1.Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow chart of search results.

Figure 1 .
Figure 1.Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow chart of search results.

*
Level of evidence according to the Scottish Intercollegiate Guidelines Network [SIGN]), ranging from 1++ for high-quality meta-analyses, systematic reviews of clinical trials, or high-quality clinical trials with very small risk of bias to 4 for expert opinions.** GRADE scale for quality of evidence (Aguayo-Albasini et al., 2014)[39], ranging from High, for high confidence in the agreement between real and estimated effect to Very low, for little confidence in the estimated effect, which is highly likely to differ from the real effect.*** Grade of recommendation according to the Scottish Intercollegiate Guidelines Network (SIGN)[40], ranging from A for at least one meta-analysis or clinical trial classified as 1++ and directly applicable to guideline target populations to D for level 3 or 4 scientific evidence or evidence extrapolated from studies classified as 2+.J. Clin.Med.2024, 13, x FOR PEER REVIEW 16 of 26

Figure 3 .
Figure 3. Distribution of the geographic origin of selected articles.

Figure 3 .
Figure 3. Distribution of the geographic origin of selected articles.

7. 1 .
Efficacy and Safety 7.1.1.Superficialis-to-Profundus Tendon (STP) Transfer STP transfer was first proposed in 1974 by Braun et al. [21] to improve hand hygiene in patients with spastic clenched-fist deformities of the hand and no volitional control [50].

Table 2 .
Summary of articles included in the review.

Table 3 .
Quality of evidence and grade of recommendation for studies in the systematic review.

Table 4 .
Types of surgery and frequency of their application in the reviewed studies.

Table 4 .
Types of surgery and frequency of their application in the reviewed studies.

Table 5 .
Outcome evaluation methods used in the reviewed studies.