Outcome following neurectomy of the deep branch lateral plantar nerve and plantar fasciotomy for hindlimb proximal suspensory desmopathy in western performance horses: 21 cases

Abstract

Objective: To report the outcome of horses used in western performance disciplines after deep branch lateral plantar neurectomy/fasciotomy surgery for hind limb proximal suspensory desmopathy (PSD). Study design: Retrospective analysis. Sample population: Twenty-one client-owned horses. Methods: Medical records were reviewed (2009-2019) for horses involved in western performance disciplines that had been treated with deep branch lateral plantar neurectomy and plantar fasciotomy for lameness due to hind limb PSD. Follow-up was obtained by reexamination and/or verbal interviews with owners >2 years postoperatively. Results: Sixteen quarter horses and five paints were used for western pleasure (14/21), barrel racing (2/21), cutting (1/21), steer wrestling (1/21), working cow horse (1/21), team roping (1/21) and reining (1/21). A median duration of 8 months was required before horses were able to resume training or athletic work. Nine horses were able to return to a similar or higher level of athletic use, nine horses returned to a lower level of athletic performance, and three horses could not return to intended function. Owner satisfaction with outcome after the procedure was high (16/21), average (3/21), and low (2/21). Conclusion: Deep branch lateral plantar neurectomy and plantar fasciotomy allowed most horses to resume some athletic function as western performance horses. Clinical significance: These results provide evidence of potential outcomes when considering surgical treatment of hind limb PSD in western performance horses.

Neurovascular variations in the proximal plantar metatarsal region of the horse

“…The majority of limbs (97%; 29/30) contained only one DBLPN, similar to that reported in 90% (9/10) of cadaver limbs and in 95% of clinical cases at surgery 2,3 . The DBPLN consistently provides exclusive innervation to the proximal portion of the SL and therefore correct identification and removal of a section of the DBPLN should lead to successful neurectomy to the proximal portion of the SL 1,3‐5 …”

“…2,3 The DBPLN consistently provides exclusive innervation to the proximal portion of the SL and therefore correct identification and removal of a section of the DBPLN should lead to successful neurectomy to the proximal portion of the SL. 1,[3][4][5] The relationship of the DBLPN to the deep plantar arch, however, varied between horses and also between limbs unlike previously reported where the entry of the DBLPN into the proximal portion of the SL was always deep to the plantar arch. Lateral is to the left and distal is to the top of the image.…”

“…Removal of a section of the DBLPN with or without sectioning of the deep metatarsal fascia (fasciotomy) has been described as an effective treatment for desmitis of the proximal portion of the SL. [3][4][5] The rationale for neurectomy is based on the presence of compressive damage to the DBPLN in clinical cases, as described by Toth et al, 6 but also possibly through inducing local neurogenic atrophy of remaining muscle fibres in the proximal portion of the SL as documented in the fore limb. 7 Fasciotomy of the deep metatarsal fascia on the plantar aspect of the SL is often combined with neurectomy in a bid to relieve pressure to the adjacent SL, akin to releasing procedures in compartment-like syndrome.…”

Suspensory ligament size does not change after plantar fasciotomy and neurectomy of the deep branch of the lateral plantar nerve by ultrasonographic assessment

“…To better understand the long‐term effect of PFN on PSL‐CSA, later time points should be studied and although we had a follow up of greater than 12 months on 10 horses, longer term follow up may be useful. However, in the context of monitoring the horse as it returns to full work, these early postoperative data are helpful as our report, and those of others, calls for return to full work by 3 months after surgery 1,7,8 . Another limitation that we noticed despite excellent intraclass correlation coefficients, agreement indices, and narrow limits of agreement, was that our blinded and randomized design could have limited the matching of PSL shape between sonograms (Figure 4).…”

“…Serial ultrasonographic examinations are often used during the management of PSD and a reduction of PSL size is one parameter that is used to indicate readiness for the advancement of the exercise level 2,10 . In horses treated surgically by PFN, the current literature describes return to athletic use approximately 2 months postoperatively, without serial ultrasonographic guidance 1,7 . Whether the PSL size by ultrasonographic assessment changes after a PFN in clinical patients is unknown.…”