Clinical impact of the timing of tourniquet release in open fasciectomy for Dupuytren’s contracture: a cohort study

a proximal stump precluded conventional grafting. A sensory nerve transfer from the third CDN beyond its bifurcation was undertaken. The CDN along with the UDN and RDN branches to themiddle and ring fingers were dissected well outside the zone of injury and transferred to allow tension free microsurgical neurorrhaphy to the RDN and UDN of the thumb with 9-0 ethilon (Ethicon Inc., Somerville, NJ, USA) and Tiseel fibrin glue (Baxter, Deerfield, IL, USA) (Figure 1). The wound was closed primarily, and he was commenced on hand therapy 1 week after surgery. At 6-month follow-up, the patient reported no neuropathic pain. He could detect 2 g force on Semmes– Weinstein monofilament testing, with 12mm static and 10mm moving two-point discrimination in both RDN and UDN distributions on the thumb, suggestive of restored protective sensation. He had no difficulty with lack of sensation in the third CDN territory. Sensory nerve transfers provide an excellent option for the restoration of sensation to critical digits allowing for a functional, as opposed to anatomical, reconstruction of neuronal defects (Brown and Mackinnon, 2008). The technique described has several advantages. The need for a single coaptation as opposed to two in grafting reduces the risk of technical errors. It allows for a shorter reinnervation time due to the improved proximity of nerve endings and presents a more reliable donor nerve dissected outside of the zone of injury as opposed to endto-side neurorrhaphy between a graft and the median nerve. The success of this technique is dependent on patient factors. It sacrifices normal sensation to two less critical digits and may be difficult to adapt to for patients with poor cortical plasticity. Our patient initially had a positive Tinel’s test in the third web when tested in the thumb but was not bothered by this, and this had settled at his final follow-up appointment. Nerve transfers in the hand have largely been described in the context of brachial plexus injury, rather than in acute trauma. These include transfers from the fourth webspace, the dorsal sensory branch of the radial nerve and the sensory components of the third web space with fascicles isolated proximally at the median nerve to the thumb (Brown and Mackinnon, 2008). Our case demonstrates it is a viable option for patients with large or unreconstructable defects to the thumb. This novel technique for sensory reinnervation of the thumb provides good outcomes and is potentially a lifeboat in patients with significant digital nerve injuries to the thumb.

and 7 cm to the radial digital nerve (RDN). The lack of a proximal stump precluded conventional grafting. A sensory nerve transfer from the third CDN beyond its bifurcation was undertaken. The CDN along with the UDN and RDN branches to the middle and ring fingers were dissected well outside the zone of injury and transferred to allow tension free microsurgical neurorrhaphy to the RDN and UDN of the thumb with 9-0 ethilon (Ethicon Inc., Somerville, NJ, USA) and Tiseel fibrin glue (Baxter, Deerfield, IL, USA) ( Figure 1). The wound was closed primarily, and he was commenced on hand therapy 1 week after surgery.
At 6-month follow-up, the patient reported no neuropathic pain. He could detect 2 g force on Semmes-Weinstein monofilament testing, with 12 mm static and 10 mm moving two-point discrimination in both RDN and UDN distributions on the thumb, suggestive of restored protective sensation. He had no difficulty with lack of sensation in the third CDN territory.
Sensory nerve transfers provide an excellent option for the restoration of sensation to critical digits allowing for a functional, as opposed to anatomical, reconstruction of neuronal defects (Brown and Mackinnon, 2008). The technique described has several advantages. The need for a single coaptation as opposed to two in grafting reduces the risk of technical errors. It allows for a shorter reinnervation time due to the improved proximity of nerve endings and presents a more reliable donor nerve dissected outside of the zone of injury as opposed to endto-side neurorrhaphy between a graft and the median nerve. The success of this technique is dependent on patient factors. It sacrifices normal sensation to two less critical digits and may be difficult to adapt to for patients with poor cortical plasticity. Our patient initially had a positive Tinel's test in the third web when tested in the thumb but was not bothered by this, and this had settled at his final follow-up appointment.
Nerve transfers in the hand have largely been described in the context of brachial plexus injury, rather than in acute trauma. These include transfers from the fourth webspace, the dorsal sensory branch of the radial nerve and the sensory components of the third web space with fascicles isolated proximally at the median nerve to the thumb (Brown and Mackinnon, 2008). Our case demonstrates it is a viable option for patients with large or unreconstructable defects to the thumb.
This novel technique for sensory reinnervation of the thumb provides good outcomes and is potentially a lifeboat in patients with significant digital nerve injuries to the thumb.

Declaration of conflicting interests The authors
declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The authors received no financial support for the research, authorship, and/or publication of this article. There is currently no consensus on the best time to deflate the tourniquet in hand surgery. Since the introduction of the 'Wide Awake Local Anaesthesia, No Tourniquet' (WALANT) method, the tourniquet is used less frequently. However, some surgeons still prefer to use one during open Dupuytren's disease surgery to allow better visualization of the anatomical structures in the surgical field. In a systematic review, wound-healing complications were found in 23% and haematoma formation occurs in approximately 2% of cases (Denkler, 2010), which increases the risk of infection and may also compromise the viability of the skin flap. Some authors have attributed this complication to wound closure before deflating the tourniquet (Eberlin and Mudgal, 2018). In an experimental animal study, tourniquet release after wound closure was associated with more haematoma formation (Himel et al., 1989).

ORCID iD
We have retrospectively studied patients who underwent surgery for Dupuytren's contracture by open fasciectomy (including partial and total fasciectomy, VY-and Z-plasties, but excluding the open palm technique) between January 2020 and March 2022. The inclusion criteria were the presence of a Dupuytren's cord with a flexion contracture limiting hand function assessed at the metacarpophalangeal joint of more than 30 or a proximal interphalangeal joint contracture more than 15 , no previous surgery in the same hand and patients without any coagulation disorder. In Group 1 the tourniquet was deflated after the wound had been closed and a compression dressing applied. In Group 2 the tourniquet was deflated for haemostasis before closing the wound. All the operations were done by the same experienced operating team, under infraclavicular brachial plexus block for regional anaesthesia, a pneumatic tourniquet inflated to 250 mmHg and with antibiotic prophylaxis. Our team does not have a defined pattern on when to deflate the tourniquet and the decision is made in the operating room without following any specific criteria.
We recorded the number of fingers affected and the Tubiana staging system. The adverse outcomes assessed were: infection (defined as patient recall of the need for at least one postoperative course of antibiotics that was not prescribed as prophylaxis); haematoma (defined as patient who needed removal of a few sutures and the expressing of the collection); delayed wound healing (defined as dehiscence after wound closure); and skin loss (defined as skin necrosis that required a graft or flap for treatment). All patients were attended by the same nurse during follow-up. Surgical time was also assessed between both groups (time from the beginning of the intervention to closure of the wound and application of a compression dressing).
Statistical analyses were conducted using the chisquared test for categorical variables and Student's t-test for continuous variables. Follow-up started at the inclusion of patients. The level of significance was set as p < 0.05 and a 95% confidence interval (CI) was calculated.
We included 112 patients in this study. Forty-one patients were excluded because they did not meet the inclusion criteria. The minimum follow-up was 3 months (range 3-18). There were no statistical differences in demographic and baseline study data between both groups (Table 1). The percentage of complications in Group 1 was 8.8% and 7.3% in Group 2. There were no statistical differences in the complications studied The data from this historical cohort study do not support that releasing the tourniquet after wound closure is associated with more early postoperative complications. The only case of postoperative haematoma in this study occurred in Group 2 (deflation before closure). Skin loss was the only complication with a higher incidence in Group 1 (deflation after closure), but with no statistical significance.
Patients who underwent surgery without releasing the tourniquet until after wound closure were found to have a shorter operating time (p ¼ 0.003). The difference was 6 minutes (95% CI 2 to 10). The shorter operating time is likely to be due to less time being spent achieving haemostasis.
There are limitations to the current study: it was a non-randomized retrospective study; a much larger sample would be needed in a trial to detect possible differences in the incidence of complications; and we did not assess postoperative pain in either group.

Declaration of conflicting interests The authors
declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding
The authors received no financial support for the research, authorship, and/or publication of this article.