Tenotomy does not affect saccadic velocities: support for the "small-signal" gain hypothesis

We investigated the effects of four-muscle tenotomy on saccadic characteristics in infantile nystagmus syndrome (INS) and acquired pendular nystagmus (APN). Eye movements of 10 subjects with INS and one with APN were recorded using infrared reflection, magnetic search coil, or high-speed digital video. The expanded nystagmus acuity function (NAFX) quantified tenotomy-induced foveation changes in the INS. Saccadic characteristics and peak-to-peak nystagmus amplitudes were measured. Novel statistical tests were performed on the saccadic data. Six out of the 10 INS subjects showed no changes in saccadic duration, peak velocity, acceleration, or trajectory. In the other four, the differences were less than in peak-to-peak amplitudes (from 14.6% to 39.5%) and NAFX (from 22.2% to 162.4%). The APN subject also showed no changes despite a 50% decrease in peak-to-peak amplitude and a 34% increase in NAFX. The "small-signal" changes (peak-to-peak nystagmus amplitude and NAFX) were found to far exceed any "large-signal" changes (saccadic). Tenotomy successfully reduced INS and APN, enabling higher visual acuity without adversely affecting saccadic characteristics. These findings support the peripheral, small-signal gain reduction (via proprioceptive tension control) hypothesis. Current linear plant models, limited to normal steady-state muscle tension levels, cannot explain the effects of the tenotomy.     

Modifications in the histochemical and biochemical changes in tenotomized rat soleus by denervation

Response of tenotomized rat soleus muscle to denervation performed at different time intervals, has been investigated. Tenotomized muscles showed typical central core lesions seven days post-operatively. These were not observed in m-ATPase stained sections of simultaneously denervated and tenotomized muscles, and muscles denervated 24 h after tenotomy. Central core lesions were not prevented in muscles denervated 28 h after tenotomy, indicating that tenotomy effects responsible for central lesions are completed by this time. Myosin light chain pattern of muscles denervated 28 h after tenotomy, and tenotomized only were similar showing increased LC₃/LC₁ ratio. Simultaneously denervated and tenotomized muscle however showed all the three light chains relatively equal in quantity. The results suggest that elimination of neural activation within 28 h prevents myofibrillar loss and minimized other changes which occur due to tenotomy.     

Saving the foot: Simple orthopaedic surgical intervention demonstrates improved outcomes and reduced costs

BackgroundForefoot ulceration in diabetes requires significant resources, with high cost and low rates of success. The authors present the results of tendon procedures (percutaneous toe tenotomy and percutaneous tendo-achilles lengthening) under local anaesthetic to adjust mechanics in patients with diabetic neuropathic forefoot ulceration.MethodsRetrospective review of electronic patient record of 19 patients (22 feet) undergoing local anaesthetic tendon procedures between April 2019 and April 2021 with a 12 month follow up period. Size of ulcer, rate of ulcer healing, complication rates and ulcer recurrence were recorded and compared to a population of conservatively-managed patients (14 patients, 15 feet) treated prior to the introduction of tendon procedures. All clinical information obtained from electronic patient records.ResultsAll patients undergoing tendon procedures achieved complete ulcer healing at a mean time of 3.3 weeks for toe tip ulcers (after toe tenotomy) and 4.5 weeks for metatarsal head ulcers (after Achilles lengthening). There were no admissions for diabetic foot sepsis, reduced recurrence, reduced amputation rates and no mortality.Of the conservatively managed cohort, only 3 of the 15 achieved ulcer resolution without recurrence within the 12 month study period.The cohort managed conservatively had an average cost of £ 9902 per patient, per annum. The intervention cost was £ 1211 per patient, saving an average of £ 8691 per patient, per annum with ulcer resolution (88 % reduction in costs).ConclusionSignificant patient benefit, reduction in resource use and cost saving was seen with this simple intervention, which merits full evaluation in a clinical trial.Level of EvidenceLevel-IV     

Techniques,anaesthesia preferences,and outcomes of Achilles tenotomy during Ponseti method of idiopathic clubfoot correction: A systematic review

BackgroundAchilles tenotomy (AT) forms an important aspect of Ponseti’s casting method and is performed in 80–90% of idiopathic clubfoot cases to correct residual hindfoot equinus. Different techniques are described in the literature with no clarity on which method is superior. This review aims to analyse the various techniques described, anaesthesia preferences, and outcomes of AT.MethodsWe searched PubMed, Embase, Scopus, and Ovid MEDLINE for articles describing idiopathic clubfoot cases undergoing primary AT during Ponseti’s casting method. Data were extracted from eligible studies for qualitative and quantitative synthesis. The repeat tenotomy and complication rates were taken as outcome parameters.ResultsNineteen studies were included for systematic review. A percutaneous AT using a scalpel or needle is adequate in most cases and shows promising results. The out-patient department (OPD) tenotomies under local anaesthesia (LA) and operation room (OR) tenotomies under general anaesthesia (GA) were associated with a repeat tenotomy (RT) rate of 2.5% (95%CI, 0.4−5.4%) and 0.8% (95%CI, 0–1.6%), respectively. The difference between OPD and OR groups was not statistically significant (p = 0.875). The pooled analysis shows a failure/relapse rate of 4.2% (1.9–6.4%, p < 0.001) after AT. OPD and OR tenotomies were associated with a complication rate of 1.6% (95%CI, 0.2–3.0%) and 0.5% (95%CI, 0.1–0.8%), respectively, and the difference was not statistically significant (p = 0.807). Bleeding is the most common complication and is controlled in most cases by applying local pressure.ConclusionPerforming Achilles tenotomy in OPD under LA is safe and cost-effective with similar success rates to those done under GA. With the lack of many comparative and higher-level evidence studies at present, we can’t conclude if one technique is better than another.     

A comparison of percutaneous and mini-open techniques of Achilles tenotomy: an experimental study in rats

Purpose  

To investigate the effect of Achilles tenotomy performed percutaneously and by mini-open methods on tendon healing and final strength.     

Ultrasound-Guided Percutaneous Tenotomy of Biceps Tendon: Technical Feasibility on Cadavers

We tested the technical feasibility of ultrasound-guided percutaneous tenotomy of the long head of the biceps tendon (LHBT) in cadavers. Both shoulders of two fresh cadavers were scanned anteriorly to evaluate the extra-articular portion of the LHBT. Under ultrasound monitoring, a scalpel was advanced obliquely up to touch the superficial medial side of the LHBT, cutting it until the tendon was not visible anymore. Ultrasound evaluation was repeated after the procedure, and anatomic dissection was performed. The procedure was 100% feasible: four cuts were made to completely sever the tendon; the duration was less than 1 min. Skin incision measured 5 mm in two cases and 6 mm in two cases. Anatomic dissection confirmed complete tendon cut in all cases with proximal and distal tendon stumps very close to each other. Ultrasound-guided percutaneous LHBT tenotomy was 100% technically feasible in cadavers with a quick procedure and minimal cutaneous incision.     

Surgery for unilateral and bilateral patellar tendinopathy: a seven year comparative study

Purpose

Open surgery for patellar tendinopathy allows patients with unilateral and bilateral tendinopathy to return to high levels of physical activity.

Materials

Two groups of 23 athletes each underwent open surgical exploration for management of patellar tendinopathy. One group suffered from unilateral patellar tendinopathy (unilateral group), and the other group had bilateral (bilateral group) patellar tendinopathy. Maximum voluntary isometric contraction and anthropometric measures were assessed pre-operatively and at an average follow-up of seven years. The Victorian Institute of Sport Assessment (VISA)-P scoring system was also administered; functional outcomes were classified from excellent to poor according to a modification of Kelly’s criteria.

Results

At the final follow-up, in both groups, VISA-P scores were significantly improved compared with preoperative values, with no intergroup differences. Clinical results were excellent or good in 21 patients in the unilateral and 19 in the bilateral group. Twenty of 23 patients in the unilateral group and 17 of 23 in the bilateral group were still active in sports (p = 0.2). In the unilateral group, at the last follow-up, thigh volume and strength were significantly improved compared with baseline, with significant difference between operated and nonoperated limbs. In the bilateral group, there were no significant differences in thigh volume and strength between the dominant and nondominant limbs both before and after the index procedure.

Conclusions

This procedure is not technically demanding and provides a high rate of good and excellent outcomes in the long term.     

Effects of motor nerve anesthesia and tenotomy on muscle membrane properties

Motor nerves to soleus muscles of rats were kept anesthetized for up to 7 days by applying solutions of lidocaine base or marcaine HCl. The anesthetic solutions were delivered from a subcutaneously located ALZA-minipump and reached the nerves through silastic cuffs. The ACh supersensitivity of muscles inactivated by nerve anesthesia for 3–7 days was comparable to that of muscles denervated for the same length of time.g _m/g_k (the ratio of total membrane conductance to the membrane K conductance) decreased from a normal value of 5–10 to less than two in 6–7 days, in anesthetic-inactivated and denervated muscles. The results were variable after 3 days of anesthesia.g _m/g_k of muscles which were tenotomized for 3 weeks was unchanged. The voltage-current curve for muscles kept in a solution containing 50 mM K propionate, which is steep at +50 mV, was less steep in denervated and anesthetic-inactivated, but not in tenotomized muscles, although atrophy was marked in all non-normal muscles.