Modified mini-open carpal tunnel release: A technical note with patient-reported and clinical outcomes

Abstract

Introduction

Carpal tunnel release (CTR) is a highly effective surgical procedure, but differences in exposure (conventional open, mini-open, endoscopic) may influence outcomes. Contemporary CTR reporting prioritizes patient-reported outcomes such as the Disabilities of the Arm, Shoulder and Hand (DASH) and the Boston Carpal Tunnel Questionnaire (BCTQ), while peripheral-nerve–specific quality-of-life measures remain largely under-reported in CTR.

Research question

Is modified mini-open carpal tunnel release (mMOCTR) non-inferior to standard open carpal tunnel release in terms of clinical and patient-reported outcomes?

Material and methods

We describe a single-center case series of adults treated with mMOCTR using a short palmar incision, no tourniquet, meticulous bipolar hemostasis, and tactile “crisp snap” guided stepwise division of the transverse carpal ligament. Primary outcomes were DASH, BCTQ and Peripheral Nerve Surgery Quality of Life (PNSQoL) results, while the secondary outcomes were surgical complications.

Results

Out of 224 patients (291 hands) operated for CTR during the study period, 115 patients (166 hands) fulfilled the inclusion criteria. All patient reported outcomes improved significantly. Recurrence occurred in 8 hands (2.7%), and two cases of persistent pillar pain and two wound dehiscences were noted. No vascular or neural injury was noted.

Discussion and conclusion

mMOCTR delivered substantial symptom, function, disability, and QoL gains, non-inferior to those of the conventional open and mini-open techniques. As a single-center, noncomparative case series, comparative multicenter studies and technical standardization across mini-open variants are warranted to confirm these findings.

Highlights

• •Modified mini-open carpal tunnel release preserves direct-vision decompression within a limited-incision, stepwise workflow.
• •StepWise thin-layer TCL division uses a controlled “knife-down” maneuver guided by the tactile “crisp snap” to limit blade travel when visualization is reduced.
• •DASH, BCTQ-SSS/FSS, and PNSQoL improved significantly after surgery in 115 patients (166 hands) with complete paired outcome data.
• •The study provides the first CTS cohort dataset using the institution-developed PNSQoL, offering initial reference values for future work.

1. Introduction

Carpal tunnel release (CTR) is an established and highly effective operation and remains the definitive treatment for persistent or severe carpal tunnel syndrome (CTS). The procedure achieves decompression of the median nerve by dividing the flexor retinaculum (transverse carpal ligament - TCL), thereby enlarging the confined carpal tunnel space and reducing intratunnel pressure (Padua et al., 2016). Since Phalen's pivotal descriptions in the 1950s–1960s (Phalen, 1951, 1966), CTR has become one of the most commonly performed hand procedures worldwide, with contemporary long-term series generally reporting high rates of symptom relief and functional improvement (Sayegh and Strauch, 2015).

Three operative approaches are most frequently used today: conventional open CTR (OCTR), mini-open CTR (MOCTR), and endoscopic CTR (ECTR) (Li et al., 2020; Schwarz et al., 2022; Zyluk et al., 2020). Randomized trials and meta-analyses consistently show comparable long-term efficacy among these techniques, while differences are most apparent in the early postoperative course- ECTR (and, in many series, MOCTR) is associated with earlier return to activities and less scar tenderness, whereas ECTR may carry a slightly higher risk of transient neurologic irritation in some studies. (Sayegh and Strauch, 2015; Li et al., 2020; Ekhtiari et al., 2025; Hammert et al., 2024a; Zuo et al., 2015). Because “mini-open” refers to a range of incisions, exposures, and release strategies, detailed technical reporting remains important: small modifications in exposure, ligament-division method, and completeness checks may plausibly influence early pain, pillar symptoms, and revision risk, even when long-term outcomes converge (Hammert et al., 2024a).

Accordingly, outcome reporting in CTS surgery has increasingly relied on validated patient-reported outcome measures (PROM), most commonly the Boston Carpal Tunnel Questionnaire symptom severity scale (BCTQ-SSS) and functional status scale (BCTQ-FSS) and upper-extremity disability metrics such as Disabilities of the Arm, Shoulder and Hand questionnaire (DASH). In recent randomized data, BCTQ symptom and function scores typically improve to near-minimal levels by 1 year after CTR, and both DASH and BCTQ demonstrate substantial postoperative improvement across surgical approaches (Schwarz et al., 2022; Graham, 2008; Levine et al., 1993; Louie et al., 2013; Hammert et al., 2024b). However, there is unreported experience applying the Peripheral Nerve Surgery Quality of Life questionnaire (PNSQoL), which was developed by our group. (Savić et al., 2024).

In this technical note, we present a modified mini-open CTR (mMOCTR) designed to preserve direct-vision safety of open release while incorporating technical steps intended to optimize early recovery in a series of 115 patients. Clinical outcomes are reported using DASH, BCTQ, and the PNSQoL instrument, providing both conventional benchmarking against the CTS literature and an initial CTS-focused application of a peripheral-nerve–specific quality-of-life measure.

2. Methods

This case series evaluated clinical and patient-reported outcomes after a MMO for CTS. Patients were treated at the Clinic for Neurosurgery, Military Medical Academy, Belgrade, Serbia, between January 2019 and March 2025. The study was conducted in accordance with the Declaration of Helsinki. All patients provided written informed consent for surgery; patients contacted for postoperative outcome assessment provided additional consent for questionnaire administration and this study.

2.1. Participants

Eligible patients were 18–65 years of age with clinically typical CTS symptoms and electrodiagnostically confirmed median mononeuropathy at the carpal tunnel, defined by at least one of the following (Padua et al., 2016): prolonged distal motor latency >4.2 ms (Phalen, 1951); prolonged sensory latency >3.5 ms; and/or (Phalen, 1966) reduced sensory conduction velocity across the carpal tunnel <50 m/s.

Inclusion criteria were (Padua et al., 2016): CTS treated with the modified mini-open technique (index procedure) (Phalen, 1951); availability for follow-up (outpatient visit and/or structured telephone interview); and (Phalen, 1966) completed baseline and postoperative patient-reported outcome measures when applicable.

Exclusion criteria were (Padua et al., 2016): traumatic median nerve injury (Phalen, 1951); space-occupying lesions or peripheral nerve sheath tumors involving the median nerve as the primary cause of symptoms (Phalen, 1966); revision carpal tunnel release (Sayegh and Strauch, 2015); secondary CTS in which a systemic disease or specific etiology (e.g., inflammatory rheumatic disease, endocrine/metabolic disease, post-traumatic CTS) was considered the predominant driver of symptoms; and (Li et al., 2020) incomplete documentation or inability to complete follow-up assessment.

2.2. Data sources and follow-up

Baseline demographic, clinical, electrodiagnostic, and operative variables were abstracted from institutional medical records. Postoperative outcomes were obtained at routine outpatient follow-up and/or by structured telephone interview after at least six months postoperatively using standardized questionnaires. Median follow up was 35,3 months with interquartile range 21,1 to 61,4 months. Early postoperative complications were captured from medical documentation and follow-up contacts and reported descriptively.

2.3. Outcome measures

Primary outcomes were patient-reported symptom severity, function, and disability assessed with DASH, BCTQ and PNSQoL (institution-developed instrument; continuous score; scoring described in Appendix A) questionnaires. For patients who underwent bilateral surgery, observations were averaged before analysis. Specifically, the mean preoperative and mean postoperative scores were used, thereby preserving statistical independence. Early postoperative surgical complications (wound dehiscence, infection, hematoma) were monitored and recorded.

2.4. Surgical technique

All procedures were performed as day-case surgeries. The operating table was prepared with a hand stand on the operative side. The patient was placed supine; the shoulder was abducted and the elbow extended on the hand table with the forearm supinated. The surgeon is typically sitting on the ulnar side of the hand; an assistant or scrub nurse was positioned opposite.

With the patient's fingers gently splayed and the hand elevated, the operative field was sprayed with an alcohol-based antiseptic (two to three applications). In older patients or those unable to maintain elevation, the assistant supported the hand while the antiseptic dried. Standard sterile draping followed.

Procedures were performed without a tourniquet relying on meticulous bipolar coagulation and gentle tissue handling underlocal anesthesia.

A 30–35 mm longitudinal palmar incision was made in the projection of the median nerve, centered over the carpal tunnel. Practical surface landmarks included: a line in the axis of the ring finger (third web-space line) and the thenar crease; the incision was placed ulnar to the palmar cutaneous branch zone and proximal to Kaplan's cardinal line distally. When palpable, the palmaris longus tendon served as an additional reference. A No. 15 blade was used with assistant applying gentle pressure to the surrounding subcutaneous plane. Hemostasis was obtained with low-power bipolar coagulation, avoiding thermal spread (Fig. 1).

Fig. 1.

Intraoperative photographs.

A self-retaining retractor was introduced to optimize exposure. Dissection proceeded carefully to the transverse carpal ligament (TCL). In this layer, fibers of the thenar musculature may be encountered; they can be gently mobilized with a small elevator without provoking bleeding or requiring additional coagulation.

Once the TCL was fully visualized, it was divided in thin layers (Fig. 2, Fig. 3). The surgeon advanced with cautious strokes, paying close attention to the tactile “crisp snap” of the ligament as confirmation of the correct plane. When this tactile feedback was distinct, a knife-down technique (discreet downward pressure without sawing motion) could be used safely, maintaining constant tactile control. This stepwise method minimizes the risk of injury to critical structures that typically occurs with uncontrolled slicing motions.

Fig. 2.

Intraoperative photographs of TCL division.

Fig. 3.

Intraoperative photographs of TCL division.

Variants of the recurrent motor branch (including intraligamentous courses) can rarely be encountered. For this reason, decompression is performed slowly, in thin slices, with frequent mopping of the field for visualization. After an initial “window” through the TCL confirmed entry into the canal, the opening was carefully extended proximally and distally to allow gentle introduction of a small, curved hemostat. Levering the ligament upward facilitated exposure for completion of the distal and proximal release. Complete division is then achieved with blunt-tipped scissors, stepwise, using short incisions and dissecting moves (Fig. 4, Fig. 5).

Fig. 4.

Intraoperative photograph demonstrating stepwise division of the TCL using a hemostat to elevate the ligament, maintaining controlled visualization during release.

Fig. 5.

Intraoperative photographs demonstrating direct visual confirmation of complete TCL division, with exposure maintained using handheld retractors.

Proximal exposure was aided by a blunt retractor placed within the ligamentous layer (not into the canal). The surgeon palpated with a dissector or small finger to confirm absence of residual constriction, extending the release proximally if needed. Distally, care was taken in the vicinity of the thenar motor branch; routine identification of the branch was not required for an adequate release, provided the TCL was fully divided. Throughout the procedure, the awake patient may be asked to flex the fingers for tendon orientation and to oppose the thumb for a quick motor check.

After complete decompression, the wound was irrigated with 3% hydrogen peroxide and saline solutions. On removal of retractors, spot hemostasis of the subcutaneous plane was performed with bipolar cautery as needed. The skin was closed in a single layer using non-absorbable monofilament 3-0 or 4-0sutures.

During closure, the assistant rolled a strip of gauze across the wound several times to express any residual ooze and reduce hematoma formation. A thin layer of vaseline gauze and dry pads were applied. The hand was soft-immobilized with sterile cotton and a light bandage. Patients were encouraged to use a sling for comfort for the first few days but to begin active finger and wrist motion immediately to prevent stiffness.

2.5. Statistical analysis

Continuous variables were summarized as mean (standard deviation) or median (interquartile range), and categorical variables as counts (percentages). Pre-to postoperative changes in BCTQ, DASH, and PNSQoL were evaluated using paired parametric or nonparametric tests depending on distributional assumptions. All tests were two-tailed with statistical significance set at p < 0.05. Data analysis was performed using IBM SPSS Statistics 26 (IBM Corporation, Armonk, NY).

Clinically meaningful improvement was additionally examined using a responder analysis based on prespecified minimal clinically important difference thresholds from the literature for established instruments (BCTQ and DASH). For quality-of-life assessment, PNSQoL was analyzed as a continuous outcome.

3. Results

A total of 291 hands (from 224 patients) were operated during the study period. Patients age was of 53.5 years (Interquartile range 44–63). Operated side was right 169/291 (58.1%) and left 122/291 (41.9%). Of the 291 procedures, 188 (64.6%) were performed in females and 103 (35.4%) in males. Bilateral surgery was present in 63/224 (28.1%) patients. Recurrence was recorded in 8 hands (2.7% of operated hands). Regarding surgical complications, two patients reported severe pillar pain persisting at 6 months postoperatively, and two patients experienced wound dehiscence; no vascular or neural injury was observed.

Of the total number of 291 hands, there were 175 (123 patients) hands operated with mMOCTR technique. Paired pre- and postoperative patient-reported data were available for all four instruments in 115 patients (166 hands), of whom 51 underwent bilateral surgery.

In the mMOCTR group, the mean patients age was 54.0 years (Interquartile range 46–63), operated side was right in 91 of the 166 (54.8%)., and 107 (64.5%) procedures were performed in females. The remaining patients were excluded due to incomplete follow-up contact (Phalen, 1966), revision surgery (Sayegh and Strauch, 2015) or missing questionnaire data (Padua et al., 2016). All outcomes improved significantly (Wilcoxon paired tests) (Table 1):

Table 1.

Preoperative and postoperative PROMs after mMMOCTR.

Instrument	Number of patients	Mean preop.	Mean postop.	Mean improv.	95% CI	p value
DASH	115	26.30 ± 15.52	2.86 ± 7.37	23.45 ± 16.90	20.36–26.53	<0.001
BCTQ-SSS	115	3.24 ± 0.92	1.11 ± 0.76	2.12 ± 1.20	1.90–2.34	<0.001
BCTQ-FSS	115	1.83 ± 0.65	0.87 ± 0.43	0.96 ± 0.79	0.82–1.11	<0.001
PNSQoL	115	62.91 ± 12.51	77.74 ± 6.48	14.83 ± 13.72	12.32–17.34	<0.001

For bilateral patients, mean score across both operated hands was used as a single observation.

A postoperative floor effect was evident for DASH and a ceiling effect for PNSQoL. A secondary comparison of bilateral versus unilateral patients, performed at the patient level using each patient's mean improvement across operated sides, revealed no significant differences between the two groups.

4. Discussion

In this case series, we report outcomes after a MMO technique designed to retain the safety of direct-vision decompression while incorporating planned technical steps aimed at optimizing recovery.

Our approach uses a short palmar incision with landmark-based placement, no tourniquet, meticulous bipolar hemostasis, and stepwise, thin-layer division of the transverse carpal ligament under constant visual and tactile control. In our experience, operating without a tourniquet did not reduce visibility to a degree that compromised surgical control. Across 291 operated hands, patient-reported outcomes improved markedly: disability (DASH), symptom severity and function (BCTQ-SSS/FSS), and a peripheral nerve–specific quality-of-life measure (PNSQoL). Baseline PROM severity strongly predicted the magnitude of improvement, recurrence was uncommon, and bilateral versus unilateral cases showed similar gains.

MOCTR is a broad category with substantial heterogeneity in incision placement, exposure strategy, and how completeness of release is ensured, which complicates direct comparison across “mini” series (Chen et al., 2017; Bromley, 1994; Kasman et al., 2025; Huang and Zager, 2004; Carmo, 2020; Higgins and Graham, 2002; Muhammed Fazil et al., 2022; Kalhoro et al., 2021; Korkmaz et al., 2013; Ma et al., 2021; Mardanpour et al., 2019; Ramos-Zúñiga et al., 2017). Many published limited-incision approaches prioritize the smallest possible portal and/or more proximal or transverse skin placement, often with the primary aim of reducing scar morbidity and expediting early return of comfort and function (Carmo, 2020; Muhammed Fazil et al., 2022; Korkmaz et al., 2013; Ma et al., 2021). Other reports push minimal access further by introducing specialized concepts or instruments to enable release through extremely limited exposure (Ramos-Zúñiga et al., 2017; Chen et al., 2025). In contrast, the rationale for our modification is to preserve the minimal invasiveness of mini-open release while retaining the key advantage of conventional open CTR - direct, controlled visualization of relevant anatomical structures.

The described technique relies on incremental „knife-down” advances with careful tactile monitoring of the characteristic “crisp snap” of the TCL, alternating with frequent drying of the field using gauze or a swab to restore visualization. During these moments of tactile control, visual feedback is reduced because the blade itself obscures the plane; therefore, the safety rationale is that, precisely when visualization is limited, the maneuver minimizes uncontrolled blade travel by avoiding long slicing strokes. This is particularly important in rare cases of an intraligamentous recurrent thenar motor branch, which may be vulnerable to less-controlled cutting; in our series, one patient had this anatomic variant, and the branch was successfully identified, dissected, and decompressed without injury. Building on this principle, after a small intraligamentous “window” confirms canal entry, the ligament is elevated with a curved hemostat to facilitate depth-limited completion proximally and distally, followed by systematic confirmation of complete release by palpation, with optional awake motor checks (thumb opposition) as an additional safety signal.

The described technique is readily adoptable, and the tactile “crisp snap” represents a distinctive and highly convincing intraoperative cue, particularly in severe cases. The learning curve may therefore be short: experienced surgeons can be expected to internalize the characteristic tactile feedback after only a few cases, while surgical trainees may require several dozen supervised procedures before achieving consistent recognition.

In terms of clinical effectiveness, the magnitude and direction of PROM change in our cohort are consistent with what is typically reported after limited-incision open release: postoperative BCTQ symptom and function scores approached low residual levels, and disability improved to near-minimal values, producing the expected postoperative floor effect for DASH and ceiling effect for QOL-type measures in a successfully decompressed CTS population.

In terms of clinical effectiveness, our PROM changes closely match those reported in other limited-incision open series, with postoperative scores converging toward the low-residual end of the scale. For example, in a prospective comparative cohort, Ma et al. reported that both mini-incision and conventional open CTR improved BCTQ subscales to approximately SSS 1.3–1.5 and FSS 1.3–1.5 by 6 months, with no meaningful between-group differences at that time point, values that are very similar to our postoperative BCTQ-SSS 1.25 and BCTQ-FSS 1.07 and support that our modified mini-open release achieves the expected “near-minimal” residual symptom/function profile after adequate decompression (Ma et al., 2021). Complementing this, Saaiq's prospective mini-incision series found that 96% of wrists shifted into the “mild” postoperative BCTQ category by 4 months, paralleling the strong symptom-resolution signal seen in our cohort (Saaiq, 2021). Longer-term follow-up studies using BCTSQ total scores similarly demonstrate durable improvement after mini-open release, supporting that substantial symptom/function gains persist after the early recovery period. Large-volume mini-incision experiences likewise report pronounced symptom relief with very low rates of major complications, consistent with the safety profile we observed (no neurovascular injury) while acknowledging that “minor” morbidity such as pillar pain or superficial wound problems still occurs in a small subset (Mardanpour et al., 2019). Importantly, our study also extends the outcomes literature by applying PNSQoL to CTS surgery, an instrument developed in our center (Savić et al., 2024), providing an initial, not previously reported, PNSQoL dataset in a CTR population, alongside the more commonly reported DASH and BCTQ benchmarks.

To place these findings in the appropriate context, we acknowledge that our method represents only one of many described MOCTR modifications. This technical heterogeneity, spanning incision placement, exposure strategy, and how completeness of release is confirmed, complicates interpretation across the literature; therefore, a logical next step for the field would be to synthesize the most reproducible and risk-reducing technical elements of existing variants and propose a consensus recommendation for performing MOCTR.

Our results should also be interpreted in light of the limitations of the present study design. It is a single-center, noncomparative case series, so generalizability is limited and no superiority claims over standard open or endoscopic CTR should be made. Postoperative PROMs were collected by telephone interview, which may encourage response-patterning and courtesy/social-desirability effects. Finally, the marked DASH floor effect and PNSQoL ceiling effect reduce sensitivity for detecting subtle between-technique differences and may reflect both true recovery and reporting dynamics (including response shift), which can be relevant in publicly funded care settings; in this respect, BCTQ subscales, which retain more postoperative variance, may be better suited for comparative work, while PNSQoL is best understood as a complementary instrument capturing broader quality-of-life domains not fully addressed by symptom- or disability-focused scales. Furthermore, the PNSQoL instrument, has not yet undergone external validation, and its use in the present series should therefore be considered exploratory. Therefore, near-limit PROM results should be interpreted cautiously and confirmed in future prospective, multicenter comparative studies.

5. Conclusion

Presented modified mini-open carpal tunnel release technique (mMOCTR) preserves the key safety advantage of open CTR: direct, controlled visualization, while maintaining a limited incision within a reproducible, step-by-step workflow. The technique was associated with marked improvement in disability and symptom/function outcomes (DASH, BCTQ) as well as substantial gains in PNSQoL, similar to those in previously published series.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Appendix A. Supplementary data

The following is/are the supplementary data to this article: