Tarsal tunnel release restores sensations in sole for diabetic sensorimotor polyneuropathy

Prevention of foot ulcers in persons with diabetes at risk of ulceration: A systematic review and meta-analysis

AIMS

Prevention of foot ulcers in persons with diabetes is important to help reduce the substantial burden on both individual and health resources. A comprehensive analysis of reported interventions is needed to better inform healthcare professionals about effective prevention. The aim of this systematic review and meta-analysis is to assess the effectiveness of interventions to prevent foot ulcers in persons with diabetes who are at risk thereof.

MATERIALS AND METHODS

We searched the available scientific literature in PubMed, EMBASE, CINAHL, Cochrane databases and trial registries for original research studies on preventative interventions. Both controlled and non-controlled studies were eligible for selection. Two independent reviewers assessed risk of bias of controlled studies and extracted data. A meta-analysis (using Mantel-Haenszel's statistical method and random effect models) was done when >1 RCT was available that met our criteria. Evidence statements, including the certainty of evidence, were formulated according to GRADE.

RESULTS

From the 19,349 records screened, 40 controlled studies (of which 33 were Randomised Controlled Trials [RCTs]) and 103 non-controlled studies were included. We found moderate certainty evidence that temperature monitoring (5 RCTs; risk ratio [RR]: 0.51; 95% CI: 0.31-0.84) and pressure-optimised therapeutic footwear or insoles (2 RCTs; RR: 0.62; 95% CI: 0.26-1.47) likely reduce the risk of plantar foot ulcer recurrence in people with diabetes at high risk. Further, we found low certainty evidence that structured education (5 RCTs; RR: 0.66; 95% CI: 0.37-1.19), therapeutic footwear (3 RCTs; RR: 0.53; 95% CI: 0.24-1.17), flexor tenotomy (1 RCT, 7 non-controlled studies, no meta-analysis), and integrated care (3 RCTs; RR: 0.78; 95% CI: 0.58-1.06) may reduce the risk of foot ulceration in people with diabetes at risk for foot ulceration.

CONCLUSIONS

Various interventions for persons with diabetes at risk for foot ulceration with evidence of effectiveness are available, including temperature monitoring (pressure-optimised) therapeutic footwear, structured education, flexor tenotomy, and integrated foot care. With hardly any new intervention studies published in recent years, more effort to produce high-quality RCTs is urgently needed to further improve the evidence base. This is especially relevant for educational and psychological interventions, for integrated care approaches for persons at high risk of ulceration, and for interventions specifically targeting persons at low-to-moderate risk of ulceration.

Paradoxical Changes of Cutaneous Microcirculation and Sympathetic Fibers of Rat Hind Limbs after Sciatic Nerve Compression

BACKGROUND

Recent studies show evidence that surgical nerve decompression could improve cutaneous blood flow (CBF), which might benefit ulcer healing. However, the change of CBF and sympathetic fibers after nerve compression is poorly understood. In the current study, a unilateral sciatic nerve compression model was created in Sprague-Dawley rats.

METHODS

A laser Doppler imaging system was applied to assess the CBF of the regions below the ankles. Immunohistochemistry and transmission electron microscopy were used to investigate the histopathologic changes of sympathetic fibers in sciatic nerve samples.

RESULTS

Laser Doppler imaging revealed decreased CBF of both the lesional limb and the contralesional limb, which occurred earlier in the lesional side, indicating an enhanced sympathetic tone on vasomotor function. Intraneural density of sympathetic fibers decreased on both sides and the ultrastructure of unmyelinated fibers of both sides degenerated in a nonsynchronized manner.

CONCLUSIONS

The study revealed nonsynchronized reduced CBF of bilateral hind limbs with paradoxically degenerated and diminished sympathetic fibers in bilateral sciatic nerves after unilateral sciatic nerve compression. These results may validate the importance of and broaden the indications for surgical nerve decompression in preventing or treating foot ulcers.

Lower Extremity Nerve Decompression for Diabetic Peripheral Neuropathy: A Systematic Review and Meta-analysis

Background:

Diabetic peripheral neuropathy (DPN) is a leading cause of morbidity. This systematic review and meta-analysis evaluate the efficacy of lower extremity nerve decompression in reducing DPN symptoms and complications.

Methods:

A database search was performed using Medline, Embase, Google Scholar, and Cochrane Central Register of Controlled Trials. Articles addressing surgical decompression of lower limb peripheral nerves in patients with diabetes were screened for inclusion. Two independent reviewers undertook the assessment. Methodological quality measures were the Cochrane risk of bias and Newcastle-Ottawa scale.

Results:

The pooled sample size from 21 studies was 2169 patients. Meta-analysis of 16 observational studies showed significant improvement in the visual analog scale (VAS) (P < 0.00001) and two-point discrimination (P = 0.003), with strong reliability. Decompression of the tarsal tunnel region had the highest improvement in VAS [MD, 6.50 (95% CI, 3.56–9.44)]. A significant low-risk ratio (RR) of ulcer development and lower limb amputation was detected (P < 0.00001). Lowest RR of ulcer development was detected with tarsal tunnel release [RR, 0.04 (95% CI, 0.00–0.48)]. Improvements in VAS, two-point discrimination, and nerve conduction velocity were nonsignificant in the meta-analysis of five randomized controlled trials (RCTs). The RCT analysis was limited to only two studies for each outcome.

Conclusions:

Meta-analysis of observational studies highlights the efficacy of lower extremity nerve decompression in reducing DPN symptoms, ulcerations, and amputations. Releasing the tibial nerve in the tarsal tunnel region was the most effective observed procedure. Nevertheless, high-quality RCTs are required to support the utility of this intervention in DPN.

Tarsal tunnel syndrome: current rationale, indications and results

Tarsal tunnel syndrome (TTS) is a neuropathy due to compression of the posterior tibial nerve and its branches. It is usually underdiagnosed and its aetiology is very diverse. In 20% of cases it is idiopathic. There is no test that diagnoses it with certainty. The diagnosis is usually made by correlating clinical history, imaging tests, nerve conduction studies (NCSs) and electromyography (EMG). A differential diagnosis should be made with plantar fasciitis, lumbosacral radiculopathy (especially S1 radiculopathy), rheumatologic diseases, metatarsal stress fractures and Morton’s neuroma. Conservative management usually gives good results. It includes activity modification, administration of pain relief drugs, physical and rehabilitation medicine, and corticosteroid injections into the tarsal tunnel (to reduce oedema). Abnormally slow nerve conduction through the posterior tibial nerve usually predicts failure of conservative treatment. Indications for surgical treatment are failure of conservative treatment and clear identification of the cause of the entrapment. In these circumstances, the results are usually satisfactory. Surgical success rates vary from 44% to 96%. Surgical treatment involves releasing the flexor retinaculum from its proximal attachment near the medial malleolus down to the sustentaculum tali. Ultrasound-guided tarsal tunnel release is possible. A positive Tinel’s sign before surgery is a strong predictor of surgical relief after decompression. Surgical treatment achieves the best results in young patients, those with a clear aetiology, a positive Tinel’s sign prior to surgery, a short history of symptoms, an early diagnosis and no previous ankle pathology.

Cite this article: EFORT Open Rev 2021;6:1140-1147. DOI: 10.1302/2058-5241.6.210031

Saphenous nerve to posterior tibial nerve transfer: A new approach to restore sensations of sole in diabetic sensory polyneuropathy

BACKGROUND

Loss of sensations in the sole following diabetic sensorimotor polyneuropathy (DSPN) leads to diabetic foot ulcers and its sequelae. We hypothesized that sensory reinnervation of sole by transfer of saphenous nerve (SN) to sensory fascicles of posterior tibial nerve (PTN) in these patients may reverse the neuropathy.

METHODS

This prospective interventional case series included patients with advanced DSPN and intact sensory supply of SN. PTN was neurotized by transfer of SN nerve in the tarsal tunnel and postoperatively sensations of the sole were tested. Any existing ulcers on sole were noted and their healing was monitored.

FINDING

A total of 17 patients (22 feet), 9 male and 8 female, were included. Seven patients had ulcers in the feet. At 6 months follow-up all patients developed protective sensation in the sole. The average 2 PD improved from 60 mm to 45.5 mm, average vibration perception improved from 34.12 V to 24.33, Medical Research Council (MRC) score improved from S0 in 12 feet and S1 in 10 feet to S3+ in 13 feet, S3 in 5 feet, and S2 in 2 feet at 6 months along with healing of ulcers in all 7 feet.

INTERPRETATION

Transfer of SN to PTN for sensory neurotization is an innovative and simple option to prevent complications of DSPN. This procedure has the potential to change the natural history of DSPN.

Our experience of reinnervation of sole in diabetic sensorimotor polyneuropathy: A chance to change the natural history of disease

Diabetic sensorimotor polyneuropathy (DSPN) is the commonest form of neuropathy which leads to insensate sole, diabetic foot ulcers (DFU) and its complications. We share our experience in recovery of sensation in the sole after prophylactic surgery such as nerve decompression (ND) or sensory neurotization by nerve transfer (NT) in patients having Diabetic sensorimotor polyneuropathy DSPN. 32 patients (46 feet) were selected for either nerve decompression or sensory neurotization depending upon presence or absence of Tinel's sign at tarsal tunnel. At 6 month post-operatively perception of touch and pain recovered in all feet; temperature and pressure perception recovered in ∼95% feet; average vibration perception threshold returned to normal range and 2-Point Discrimination came down significantly. There were no ulcers or amputation in operated limbs during follow up period of 6 months. Prophylactic surgery in the form of ND and NT can be offered with minimal complications which significantly improve sensations in the sole in selected cases of DSPN. These have the potential to improve the quality of life of patient and change the natural course of disease.