Elsevier

Clinical Biomechanics

Volume 80, December 2020, 105150
Clinical Biomechanics

Lecture
Modification of intra-carpal tunnel pressure after Z-lengthening of the transverse carpal ligament

https://doi.org/10.1016/j.clinbiomech.2020.105150Get rights and content

Highlights

  • Carpal Tunnel Syndrome.

  • Flexor Retinaculum reconstruction technique.

  • Flexor Retinaculum lengthening techniques.

  • Carpal tunnel pressure.

Abstract

Background

Flexor retinaculum reconstruction techniques or simply Flexor Retinaculum Z-lengthening have been proposed to preserve Flexor Retinaculum continuity after carpal tunnel release. Their effectiveness is based solely on symptom relief. There has been no analysis of the effects on intra-carpal tunnel pressure of Flexor Retinaculum-lengthening techniques. Objective was to compare intra-carpal tunnel pressure outcomes between complete division and Z-lengthening of the Retinaculum in a cadaveric model of carpal tunnel release.

Methods

Experimental study of carpal tunnel pressure after surgical Flexor Retinaculum modification in 10 fresh-frozen forearm and hand cadaveric specimens. The Kyphon™ Balloon Kyphoplasty system was used to measure the pressure before and after infusing 1, 2, 3, 4 and 5 ml of saline solution when untreated (Flexor Retinaculum continuity stage I), when Z-lengthened (Flexor Retinaculum continuity stage II), and after complete Flexor Retinaculum division (Flexor Retinaculum continuity stage III).

Finding

Intra-carpal tunnel pressure increased with larger volume of infused saline solution, although mean pressures were lower after Z lengthening or complete division of the Retinaculum than at baseline. Analysis of linear regression coefficients indicated significant differences as a function of FR continuity stage (F(2,18) = 18.38, p < 0.001), while the Bonferroni test revealed significant differences in slopes between stages I and III (p = 0.003), between stages I and II (p < 0.02), but not between stages II and III (p > 0.05).

Interpretation

The effectiveness of carpal tunnel release and the reduction in intra-carpal tunnel pressures obtained by Z-lengthening of the FR were similar to those observed after its complete division, while preserving FR continuity.

Introduction

Traditional surgical treatment of carpal tunnel syndrome (CTS) involves division of the flexor retinaculum (FR) to relieve pressure on the median nerve (Amadio, 1995; Kohanzadeh et al., 2012), and this approach has long proven to be effective. However, some patients experience postoperative scar sensitivity, pillar pain (Ludlow et al., 1997; Roux, 2004), or grip weakness (Katz et al., 1995; Netscher et al., 1998), among other complications, delaying their return to work or normal activities.

The precise causes of adverse events related to carpal tunnel release (CTR) remain unclear, but they may be attributable to biomechanical alterations caused by FR disruption (Brooks et al., 2003; Gartsman et al., 1986; Ludlow et al., 1997; Morrell et al., 2014).

FR reconstruction after its complete division (Jakab et al., 1991; Kapandji, 1990; Karlsson et al., 1997; Lluch, 2002) or simply Z-lengthening of the FR (Castro-Menéndez et al., 2016; Simonetta, 1977) (Fig. 1) has been proposed to save FR continuity, primarily aimed at preserving the first flexor tendon pulley.

Some authors reported better results of manual function and short-term grip strength with preserving FR continuity techniques than in carpal release without carpal ligament reconstruction (Faour-Martín et al., 2014; Gutiérrez-Monclus et al., 2018; Martín et al., 2003). Conversely, other researchers found no significant differences in pillar pain, long-term grip strength, safety or functional status outcomes between complete division and FR lengthening or elongated reconstruction (Castro-Menéndez et al., 2016; Dias et al., 2004; Sike et al., 2019), in such way that any identifiable benefit in preserving the flexor retinaculum continuity when decompressing the carpal tunnel is questioned. Furthermore, it is believed that achievement of sufficient carpal tunnel decompression may be jeopardized by the preservation of FR continuity because of an erroneous similarity to a partial division, given that incomplete splitting is a prime cause of CTS persistence or recurrence (Amadio, 2009; Jones et al., 2012).

Researchers have addressed the effect on intracarpal tunnel pressure of division of the transverse carpal ligament, recording pressures in CTS before and after ligament release in patients (Goss and Agee, 2010; Sanz et al., 2005; Schuind, 2002) and cadaver specimens (Kim et al., 2013; Li et al., 2011; Nakao et al., 1998). However, although this procedure is frequently performed to relieve CTS symptoms, its effectiveness and the underlying biomechanical mechanisms remain unclear, and pressure values appear to be influenced by the compliance (Kim et al., 2013; Li, 2005; Tung et al., 2010), cross-sectional area, and carpal tunnel morphology (Li et al., 2011).

The effectiveness of FR Z-lengthening on median nerve release is solely based on symptom relief. No data are available on changes in intra-carpal tunnel pressures after FR-lengthening. The objective of this study was to compare the decrease obtained in intra-carpal tunnel pressure between complete division and Z-lengthening of the FR in a cadaveric model of CTR. We hypothesized that FR Z-lengthening and complete division would be equally effective to reduce carpal tunnel pressure.

Section snippets

Material and methods

We performed an experimental study of carpal tunnel pressure after surgical FR modification in a cadaveric model (Fig. 1). Ten forearm and hand specimens were used from ten fresh-frozen cadavers of persons (5 males and 5 females) aged between 53 and 75 years at death, who had all given informed consent to their use for scientific purposes (McHanwell et al., 2008; Riederer et al., 2012). The specimens had no previously documented wrist injuries or surgeries. All specimens were dissected, after

Results

Table 1 exhibits the mean carpal tunnel pressure values (± standard deviations) at each FR continuity stage as a function of SS infusion volume. Pressures increased with higher SS infusion volume, while mean pressures were lower after Z-lengthening or complete split of the FR than at baseline.

Fig. 5A depicts pressure curves as a function of SS infusion volume at each FR continuity stage, showing higher pressure with greater infusion volume. It can be observed in Fig. 5B that the slope of the

Discussion

To our best knowledge, this is the first study to measure the effects on carpal tunnel pressure of a CTR technique that preserves the FR. Pavlidis et al. (2010) investigated the effect of FR reconstruction by four different techniques in carpal tunnel volume, but did not take any pressure measurements. In our cadaveric model of CTR, both Z-lengthening of the FR and its complete division produced a statistically significant reduction in carpal tunnel pressure in comparison to baseline values

Declaration of competing interest

The authors declare that they have not competing interests.

Acknowledgements

Richard Davies for language review of the manuscript.

Funding

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Authors’ contributions

Substantial contributions to research design and interpretation of data: Pedro Hernández-Cortés, Olga Roda.

Acquisition and analysis of data: Patricia Hurtado-Olmo.

Drafting the paper: Pedro Hernández-Cortés, Olga Roda, Indalecio Sánchez-Montesinos.

Statistics and interpretation of data: Francisco O'Valle, Miguel Pajares-López, Andrés Catena.

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Availability of data and materials

All data generated or analyzed during this study are included in this published article.

References (53)

  • J.N. Katz et al.

    Symptoms, functional status, and neuromuscular impairment following carpal tunnel release

    J Hand Surg.

    (1995)
  • P.J. Keir et al.

    Effects of finger posture on carpal tunnel pressure during wrist motion

    J. Hand. Surg. [Am.]

    (1998)
  • K.S. Ludlow et al.

    Pillar pain as a postoperative complication of carpal tunnel release: a review of the literature

    J. Hand Ther.

    (1997)
  • K.R. Means et al.

    Release of the transverse carpal ligament alone is associated with elevated pressure beneath the distal volar forearm fascia in a cadaver model of carpal tunnel syndrome

    J. Hand. Surg. [Am.]

    (2007)
  • E. Nakao et al.

    Changes in carpal tunnel pressures following endoscopic carpal tunnel release: a cadaveric study

    Hand Surg Am.

    (1998)
  • D. Netscher et al.

    Temporal changes in grip and pinch strength after open carpal tunnel release and the effect of ligament reconstruction

    J. Hand. Surg. [Am.]

    (1998)
  • D. Rempel et al.

    Effects of forearm pronation/supination on carpal tunnel pressure

    J. Hand. Surg. [Am.]

    (1998)
  • J. Sanz et al.

    Postoperative changes of carpal canal pressure in carpal tunnel syndrome: a prospective study with follow-up of 1 year

    J Hand Surg.

    (2005)
  • C. Savornin et al.

    Should we reconstruct the flexor retinaculum in the carpal tunnel?

    Chir. Main

    (2010)
  • F. Schuind

    Canal pressures before, during, and after endoscopic release for idiopathic carpal tunnel syndrome

    J Hand Surg.

    (2002)
  • H. Seradge et al.

    In vivo measurement of carpal tunnel pressure in the functioning hand

    J. Hand. Surg. [Am.]

    (1995)
  • R.M. Szabo et al.

    Stress carpal tunnel pressures in patients with carpal tunnel syndrome and normal patients

    J. Hand. Surg. [Am.]

    (1989)
  • R. Werner et al.

    Intracarpal canal pressures: the role of finger, hand, wrist and forearm position

    Clin. Biomech.

    (1997)
  • A. Yoshida et al.

    Is complete release of all volar carpal canal structures necessary for complete decompression in endoscopic carpal tunnel release?

    J. Hand Surg. Eur.

    (2007)
  • Y.S. Chen et al.

    Comparison of two ways of altering carpal tunnel pressure with ultrasound surface wave elastography

    J. Biomech.

    (2018)
  • O. Faour-Martín et al.

    The Simonetta technique for carpal tunnel syndrome: immediate postoperative evaluation and long-term comparative study

    Int. J. Orthop.

    (2014)
  • View full text