Revision Endoscopic Carpal Tunnel Release: An Update on Technique and Outcomes

Abstract

Background:

Carpal tunnel release is among the most frequently conducted upper extremity procedures. While it typically provides patients with improved sensation, decreased pain, and improved function, a small percentage of cases require revision due to failed initial surgery. Consequently, adoption of endoscopic techniques for carpal tunnel revision procedures is beginning to be explored.

Methods:

A retrospective analysis was conducted of postoperative clinical visits and patient-reported outcome measures for four patients who had undergone five endoscopic revision carpal tunnel release procedures (one patient had bilateral disease). All five cases had symptoms consistent with recurrent carpal tunnel syndrome.

Results:

One hundred percent (5 of 5) of cases resulted in patients reporting symptom improvement. Postoperative clinical visits and improved patient-reported outcome measures (QuickDash, PROMIS Upper Extremity, VAS Pain, PSEQ, PHQ, and Surgery Satisfaction) scores from baseline to 6 weeks demonstrated successful postoperative function and symptom resolution. Five of five cases resulted in patients resuming normal activities without restrictions within 1–5 weeks, with an average of 3.4 weeks.

Conclusions:

Preliminary findings suggest the endoscopic revision procedure may be safe and effective for patients with recurrent carpal tunnel syndrome, extending the indications to include scars proximal to the wrist crease. Moreover, this minimally invasive procedure facilitates a transition back to normal activities and avoids incisions on weight-bearing surfaces of the palm. Adopting endoscopic revision may reduce the need for prolonged postoperative care and physical therapy. However, due to the limited sample size of five patients, further investigation with larger cohorts is warranted to confirm these observations.

Takeaways

Question: Can minimally invasive endoscopic revision procedures be an effective alternative to open release for patients with recurrent carpal tunnel syndrome?

Findings: A retrospective analysis of five cases of endoscopic revision carpal tunnel release showed symptom improvement in all cases, with patients resuming normal activities within an average of 3.4 weeks postsurgery. Patient-reported outcome measures indicated successful postoperative function and symptom resolution.

Meaning: Endoscopic revision procedures may be safe and effective for patients with recurrent carpal tunnel syndrome.

INTRODUCTION

In the United States, carpal tunnel release (CTR) ranks among the most prevalent upper extremity procedures, with over 600,000 procedures performed annually.¹ Although this procedure typically provides patients with improved sensation, decreased pain, and improved function, patients may experience failure of their initial surgery with approximately 1%–5% of cases requiring a revision surgery.^2,3 Patients requiring revision CTR are often grouped into persistent, recurrent, and new symptom categories.⁴ Literature on this topic does not always clearly distinguish between recurrent and persistent symptoms. Recurrence implies a return of symptoms after a symptom-free interval.⁵ Nevertheless, the persistence or recurrence of preoperative symptoms may occur after either open or endoscopic CTR of the transverse carpal ligament. Clinical signs of recurrence include numbness, night symptoms, positive provocative tests, and a positive electromyogram.^6,7 Open revision has been considered the standard approach for treatment of recurrent carpal tunnel syndrome. Adjunct procedures, such as hypothenar fat pad flaps, nerve wraps, and other procedures, may be performed alongside open revision CTR with variable success.⁸

Regarding recurrence or persistence of CTR, the most common reason is incomplete release of the distal part of the TCL.⁹ The inadequate decompression can be resolved with a complete incision of the ligament. An alternative consideration in carpal tunnel recurrence is the formation of scar tissue after the index operation. This scar tissue can result in a structure similar to that of the native TCL or involve the median nerve directly. Contributory factors may include poor hemostasis and hematoma formation, prolonged postoperative immobilization, or insufficient range-of-motion exercises and therapy. Excess scar tissue may also indirectly affect the nerve by leading to reformation of the transverse carpal ligament.¹⁰ Carpal tunnel syndrome may also recur many years after initial successful release. Reasons for the recurrence of carpal tunnel include worsening arthritis, fibrotic tissue, and additional medical problems over time that created increasing pressure within the previously released carpal tunnel. The reasons stated for recurrence in this population are consistent with previously published literature.^11,12

The purpose of the current study was to evaluate the viability of endoscopic CTR for revision carpal tunnel surgery in the setting of recurrent symptoms following open surgical release. Endoscopic revision CTR is an alternative treatment to open revision CTR that has gained interest amongst practicing hand surgeons and is continuing to be evaluated for intraoperative efficiency and postoperative patient outcomes. The endoscopic technique has proven to be successful in primary CTR. Evidence from randomized controlled trials indicates that endoscopic primary CTR exhibits improved recovery and greater patient satisfaction compared with open primary CTR.¹³ The treatment of carpal tunnel recurrence endoscopically uses the same technique as endoscopic primary CTR and may offer less morbidity and risks when compared with open, and often larger, incisions extending from the palm into the distal forearm (Fig. 1).

Fig. 1.

A 74-year-old woman who previously underwent right carpal tunnel surgery 30 years prior. The postsurgical closure of the endoscopic technique (B) displays the limited invasiveness. The scar is in a transverse fashion with no extension beyond the wrist crease. The s-shaped previous open CTR scar (A) is considerably larger and extends beyond the wrist crease.

Since the study published by Teoh and Tan⁷ on endoscopic revision CTR, there has been a notable absence of further advocacy or exploration of endoscopic revision techniques in the literature. It is important to address this gap and provide additional evidence to substantiate the safety and efficacy of endoscopic revision CTR procedures.

Further, previous literature only recommended endoscopic revision in cases where the scar did not pass the wrist crease.⁶ Trumble et al proposed and proved that endoscopic revision CTR is safe and as effective as open CTR in their study. However, as previously mentioned, there have been minimal additional studies analyzing this further. In their study, they proposed to only consider revision CTR with scars distal to the wrist crease and do not extend proximal to the wrist to avoid revision surgery within the previous scar. This current study aimed to further prove the safety and efficacy of revision endoscopic CTR, and to further highlight an additional indication. Specifically, it demonstrates that revision endoscopic CTR can be performed regardless of the scar length or position. This is due to the inherent technique of endoscopic CTR, whereby a small transverse incision is made at a wrist crease, and under direct visualization, the antebrachial fascia can be released to gain entry into the carpal tunnel. The addition of the scar proximal to the palm does not create a contraindication in that the release can be performed safely by directly entering into the space below the antebrachial fascia during the initial dissection and placement of the endoscopic device.

METHODS

Four patients (five total cases; one patient had bilateral disease) with recurrent carpal tunnel syndrome who underwent endoscopic revision CTR with a single surgeon were analyzed using postoperative clinical visits and patient-reported outcome measures (PROMs) at baseline and 6 weeks. Preoperative assessment for potential recurrence of carpal tunnel syndrome consisted of an examination of the patient’s preoperative symptoms and medical records including office visits, operative reports, and electrodiagnostic studies.

Preoperative symptom assessments included documentation of objective deficits in nerve function and scar tissue assessment to more clearly understand outcomes of the primary operative procedure.¹⁴ The performing hand surgeon hypothesizes that the absence of skin dimpling or adherence to underlying scar tissue during palpation may indicate potential failure of the primary procedure. Further, the failure of conservative management such as nighttime splinting, non-steroidal anti-inflammatory drugs, steroid injections, or therapy establishes that nonoperative options have been exhausted. Once the clinical evaluation and medical records review were substantiated by both subjective symptomatic and objective electrodiagnostic evidence of recurrent carpal tunnel syndrome, endoscopic revision CTR was recommended to alleviate the symptoms.

Indications for revision endoscopic release included patients who previously underwent open release without limitation in length of scar within the palm or extending beyond the wrist crease. This contrasts with the findings of Trumble et al,⁶ who suggested revision endoscopic CTR be limited to cases where the scar did not extend proximal to the wrist crease.

Operative Procedure

After induction of monitored anesthesia care/general plus local anesthesia, a well-padded nonsterile right upper extremity tourniquet is placed. The patient is then prepared and draped in the usual sterile fashion. After a time-out is called confirming site of surgery, an Esmarch is used to exsanguinate. The lead surgeon begins with the endoscopic incision closer to the distal wrist crease at the intersection of the palm and wrist. This is placed on the ulnar half of the palmaris longus tendon when present, which allows for better visualization of the palmaris longus tendon and scar tissue along the transverse carpal ligament. Improved exposure in this distal palm location during revision helps facilitate a complete release.

With careful tenotomy dissection, the palmaris longus tendon is identified and retracted radially exposing the antebrachial fascia. A distally based antebrachial fascia flap is then created to enter the carpal tunnel. The hook of hamate finder is used to gently debride the undersurface of the transverse carpal ligament. Dilators and the MicroAire SmartRelease Endoscopic Carpal Tunnel System (MicroAire Surgical Instruments, Charlottesville, Va.) are then brought onto the field. When adequate visualization of the overlying transverse carpal ligament is confirmed, the endoscopic instrument divides the distal 50% of the roof of the carpal tunnel, often a similar-appearing tissue to nonoperated transverse carpal ligament. The camera is reintroduced distally to confirm that there are no remaining bridging fibers, and the palmar fat is visualized. Once this is done, the proximal 50% of the transverse carpal ligament is then released. There is either visualization of the overlying preserved superficial musculature that is not violated during an endoscopic release, or superficial subcutaneous fat. Often the light of the scope can transmit through the palmar skin, confirming complete release below. In addition, the camera is rotated to confirm complete separation of the two edges of the transverse carpal ligament. The camera is also reintroduced throughout the canal to confirm that the median nerve remains intact. Once this is done, approximately 3 cm of the antebrachial fascia is released proximal to the incision with direct visualization and careful tenotomy dissection. At this point, the wound is then copiously irrigated with saline, the tourniquet is taken down, and hemostasis is obtained with bipolar electrocautery. The skin is then closed using two 4-0 nylon sutures placed in a horizontal mattress fashion. A small soft dressing consisting of Xeroform, fluffs, Sof-Rol, and Ace wrap is then applied.

Concomitant Procedures

Endoscopic revision CTR was the sole procedure done for cases 1–3 (Table 1), as well as the patient shown in Figures 1–3. The patient in case 4 underwent additional procedures during both endoscopic revision CTR procedures. Dupuytren contracture release in the thumb was performed concomitantly with the endoscopic revision CTR on the left and right sides. The successful outcomes for the patient in case 4, despite undergoing additional concomitant procedures, suggest a potential for endoscopic revision CTR to be effectively performed in combination with other hand procedures.

Table 1.

Patient-reported Outcomes at Baseline and 6-weeks following Revision ECTR

	Baseline					6 Weeks
	Patient 1	Patient 2	Patient 3	Patient 4	Mean	Patient 1	Patient 2	Patient 3	Patient 4	Mean
QuickDASH	45.45	25	52.27	45.45	42.0425	27.27	9.09	47.73	47.73	32.955
PROMIS upper extremity	31.65	45.37	36.96	34.57	37.1375	42.29	45.37	35.72	32.33	38.9275
VAS pain (last 24 h)	40	35	86	81	60.5	10	13	57	58	34.5
VAS pain (at rest)	40	17	63	76	49	10	0	33	50	23.25
VAS pain (when active)	48	31	88	78	61.25	10	13	69	61	38.25
PSEQ-1	5	5	4	2	4	5	0	5	4	3.5
PSEQ-2	5	5	4	2	4	5	0	5	3	3.25
PSEQ-2 resiliency	10	10	8	4	8	10	0	10	7	6.75
PHQ-9	8	2	12	15	9.25	2	1	14	3	5
Surgery satisfaction	—	—	—	—	—	9	7	6	10	8

Fig. 3.

This is the same patient shown in Figures 1 and 2. At the 1-week postoperative visit, the patient stated that she had no pain and started noticing improvement in symptoms. A–D, On physical examination, she had full range of motion of the affected area and could make a full composite fist (C).

Fig. 2.

This is the same patient depicted in Figure 1. The patient presented with recurrent symptoms. The transverse carpal ligament is seen with no sign of prior release (A), and release is initiated as with a primary endoscopic procedure (B). The left edge (C) and right edge (D) of the cut ligament are visualized well in the bottom views.

RESULTS

We retrospectively reviewed five cases of endoscopic revision CTR surgery. Four procedures were done on the right and one on the left. Patient ages ranged from 55 years to 76 years with an average age of 68 years. Three of the four patients were women. All patients had previously undergone open CTR between 2 and 30 years prior. All patients underwent a preoperative electromyography, which confirmed recurrence of carpal tunnel syndrome (Table 2). All patients completed patient-reported outcome surveys [QuickDash, Patient-Reported Outcomes Measurement Information System (PROMIS) UE SF, visual analog scales (VAS) pain, PSEQ, Patient Health Questionnaire (PHQ)-9 and surgery satisfaction] at baseline and 6 weeks postoperatively. The surgery satisfaction question was rated on a scale from 1 to 10, with 10 indicating the highest level of satisfaction. All patients included in the study completed the data collection period of 6 weeks.

Table 2.

Preoperative Electromyography Results for the Patients in Each Case

Case	CTS			Neuropathy
	Mild	Moderate	Severe
1			x	SDP
2		x		—
3			x	—
4 (right)			x	DPP
4 (left)		x		DPP
Patient in images			x	DPSP

DPP, diffuse peripheral polyneuropathy; DPSP, diffuse peripheral sensory polyneuropathy; SDP, severe diffuse polyneuropathy.

The patient in case 1 was a 65-year-old woman with recurrent right carpal tunnel syndrome 2 years after an open CTR. At her initial (7 days) and final (5 weeks) postoperative visits, she demonstrated the ability to make a full composite fist. By 5 weeks postoperation, her pain was controlled, and median nerve compression symptoms had improved. She was released from care without restrictions.

The patient in case 2 was a 73-year-old woman with recurrent right carpal tunnel syndrome 15 years after open surgery. At 7-days and 4-weeks postoperation visits, she could make a complete fist. By 4 weeks, she noted improvement in preoperative symptoms and was released without restrictions.

The patient in case 3 was a 55-year-old woman who underwent revision endoscopic right CTR for recurrent symptoms after prior surgery. At her 80-day follow-up, she denied difficulties, could make a fist, and was released with minimal restrictions.

The patient in case 4 was a 76-year-old man with bilateral recurrent carpal tunnel syndrome after previous bilateral open releases. The patient initially underwent right-hand endoscopic revision CTR, reported decreased pain and capacity to create a fist at 7 days and 4 weeks following surgery. He scored his surgery satisfaction 10 of 10. He then underwent left-hand endoscopic revision CTR and reported similar outcomes at 9 days and 3 weeks following surgery. He was then released without restrictions.

Overall, patients exhibited feelings of improved functional capacity and mental health and reduced pain at 6-weeks postoperative when compared with their baseline (Table 1). Pain was evaluated using a self-report questionnaire consisting of three 10-cm VAS focusing on average level of pain experienced in the past month, worst level of pain experienced over the past week, and impact of pain on self-perceived quality of life. Higher values on the respective VAS are indicative of greater average pain, worst pain, or worsened pain-related quality of life.¹⁵ Furthermore, these patients reported a relatively high surgical satisfaction (avg. 8.0 of 10.0) by 6-weeks postoperatively (Table 1).

DISCUSSION

The adaptation of the endoscopic technique in revision carpal tunnel surgery has been stagnant over the course of many years. This could be due in large part to the small portion of individuals who require secondary CTR (1%–5%), and therefore, the need to implement new techniques has not been essential. Additionally, the cost of endoscopic equipment, coupled with reimbursement rates comparable to open CTR, may deter widespread adoption. Concerns over potential nerve, vessel, and tendon injuries due to limited visualization have also been raised, although such concerns have not been validated by hand surgery literature.¹²

Few studies have been published on the success and outcomes of endoscopic revision CTR. A study conducted by Trumble et al found that among 41 patients who had undergone primary open release, 37 reported improvement after the endoscopic revision. Significant improvement was observed at 3 and 12 months after the procedure.⁶ A study completed by Teoh and Tan reported that six of six patients who underwent endoscopic revision reported resolution of symptoms ranging from 0 to 30 days with an average of 12 days. Further, with a follow-up of 7–72 months, all the patients remained symptom free and were pleased with the outcome result.⁷

The cases presented are consistent with previously published literature pertaining to endoscopic revision of carpal tunnel syndrome. In addition, our study found that successful revision endoscopic CTR surgery can be used in patients with open CTR scars that extend proximal to the wrist crease. Increased scar length from primary CTR did not increase difficulty in these cases. Further, extending the scar beyond the margins of the previous surgery was not required due to the endoscopic approach.

In addition to improved patient experiences, cost effectiveness and return on investment of endoscopic revision CTR procedures, compared with open revision CTR, should be considered.¹⁶ The endoscopic procedure limits the number of clinical visits; may reduce need for therapy; and reduces coding and billing of additional, and often unnecessary, rotational fat flaps and nerve wraps.⁸ Due to reduced recovery time, no patient in our study required postoperative therapy.

The major advantage that the endoscopic technique can provide is the potential for reduced morbidity. This is especially important when discussing the treatment of older patients who have had numerous years of relief but develop a recurrence of carpal tunnel syndrome. These patients will be much better served undergoing a minimally invasive endoscopic revision, which can potentially yield the same clinical results as an open revision regarding postoperative pain improvement and symptom resolution,³ while also possibly providing an expedited recovery time, minimal issues with using a cane or walker, and a limited need for extensive postoperative care and physical therapy.

This study serves as a reintroduction and advocacy for endoscopic revision CTR, highlighting its potential effectiveness. Beyond the limited preliminary findings suggesting the possibility of comparable clinical outcomes to open release, endoscopic revision may offer significant cost-saving opportunities by circumventing the need for adjunctive procedures like flaps, wraps, and neurolysis, which often accompany open revisions. The minimally invasive nature of the endoscopic approach has the potential to reduce morbidity, expedite recovery, and minimize functional impediments associated with larger incisions and extended operative times inherent to open revisions. The limited sample size prevents definitive conclusions of the previous statements; however, the observed outcomes warrant further investigation into endoscopic revision CTR as an effective alternative, particularly for the aging population where minimizing postoperative care needs and facilitating a quick return to functional independence are important considerations.

LIMITATIONS

This study has several limitations, including that it was retrospective and had short follow-up times. Additionally, the sample size was limited, and the lack of consistently recorded preoperative assessments, such as sensation and motor testing, further limits the comprehensive understanding of the outcomes. Furthermore, it is difficult to compare predictors of outcomes across revision carpal tunnel surgery studies due to the different outcome measures used and insufficient statistical power to examine all potential predictors. There is no standard accepted measure for evaluating outcomes in carpal tunnel syndrome. However, improvements in patient-reported symptoms, especially pain, seem to be an important indicator of success after revision surgery.¹⁷ Despite the limitations, this study shows that patients with recurrent symptoms do experience improvements in pain after endoscopic revision CTR. Further research should aim to explore the efficacy of endoscopic revision CTR specifically in patients with persistent symptoms.

Contraindications

At this time, repeat endoscopic CTR revision procedures when the primary CTR was performed endoscopically is not recommended. There are several considerations driving the recommendation. First, repeating the identical approach may be less likely to succeed if it previously failed, as unknown anatomical factors (possible unseen cysts), pathology, or technical issues may persist. Additionally, although visible scarring and adhesions from open techniques can be avoided with endoscopy, subtle underlying scarring from prior endoscopic surgery may remain problematic. Finally, new casual factors may have developed over time, contributing to recurrence.

Complications

Complications for endoscopic revision of CTRs are the same as all the primary endoscopic CTR procedures. These include neuropraxia, major nerve injuries, digital nerve injuries, tendon injuries, and arterial arch injuries.¹⁸ Adequate positioning, training, and visualization are key components to a successful revision endoscopic CTR. There were no complications in any of the five cases.

At a time when the aging population requires continued care and maintenance, recurrent carpal tunnel syndrome due to advancing arthritis and need for walkers and canes should raise the indication and adoption of a more minimally invasive yet safe and effective treatment for carpal tunnel syndrome, indicating that a revision endoscopic system should have a role in treatment for providers trained to perform this surgery.

CONCLUSIONS

This study demonstrates that endoscopic revision CTR may be a safe and effective technique for patients with recurrent carpal tunnel syndrome. The results suggest that this minimally invasive approach can be considered when previous scars extend proximal to the wrist crease, broadening the indications for use. Further research with larger cohorts and longer follow-up is recommended to confirm these findings.

DISCLOSURES

Dr. Fuller is a consultant for MicroAire Surgical Instruments (Charlottesville, Va.), but has not received funding, grants, or in-kind support for the research or preparation of this article. The other authors have no financial interest to declare in relation to the content of this article.

PATIENT CONSENT

The patient provided written consent for the use of her image.