MIDCAB (Mid-Calf Block) for Foot Surgery: A Pilot Study
Phase: PHASE4
Conditions: Ankle Surgery, Foot Surgery
Sponsor: Hospital for Special Surgery, New York

 
 
 
 
 
 
 
 
 
 
MIDCAB (Mid-Calf Block) for foot surgery: A 
pilot study  
 
 
 
FUNDER: 
Department of Anesthesiology, 
Critical Care & Pain 
Management 
PROTOCOL NO.: 
2022-0066 
VERSION & DATE: 
05/03/2022 
 
 
This document contains the confidential information of the Hospital for Special Surgery. It is provided to you and your company’s personnel for 
review. Your acceptance of this document constitutes an agreement that you will not disclose the information contained herein to others without 
the prior written consent of the Hospital for Special Surgery. No other use or reproduction is authorized by Hospital for Special Surgery, nor does 
the Hospital for Special Surgery assume any responsibility for unauthorized use of this protocol. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Confidential 
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   Protocol Number: 2022-0066 
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TABLE OF CONTENTS 
Contents 
TABLE OF CONTENTS .............................................................................................. 2 
PROTOCOL SYNOPSIS ................................................................................................... 3 
1.0 INTRODUCTION .................................................................................................. 4 
2.0 
OBJECTIVE(S) OF CLINICAL STUDY ........................................................... 5 
3.0 STUDY HYPOTHESES ........................................................................................ 6 
4.0 
STUDY DESIGN .............................................................................................. 6 
4.1 
Endpoints ......................................................................................................... 6 
4.2 
Study Sites ...................................................................................................... 6 
5.0 
STUDY POPULATION .................................................................................... 7 
5.1 
Number of Subjects ......................................................................................... 7 
5.2 
Inclusion Criteria .............................................................................................. 7 
5.3 
Exclusion Criteria ............................................................................................. 7 
6.0 
PROCEDURES ............................................................................................... 8 
6.1 
Intraoperative Protocol (update with detailed procedure) ................................ 8 
6.2 
Data Collection ................................................................................................ 9 
Pre-operative/Baseline ............................................................................................... 9 
Intra Op Data (Operating room data) .......................................................................... 9 
Pre-operative/Baseline ............................................................................................... 9 
Post-Operative Day 0 (PACU) .................................................................................... 9 
Post-Operative Day 1 (POD 1) ................................................................................... 9 
Post-Operative Day 2 (POD 2) ................................................................................... 9 
Post-Operative Day 7 (POD 7) ................................................................................... 9 
7.0 
STATISTICAL ANALYSIS ............................................................................ 10 
8.0 ADVERSE EVENT ASSESSMENT .................................................................... 10 
 

   Protocol Number: 2022-0066 
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PROTOCOL SYNOPSIS 
 
Protocol Title: 
MIDCAB (Mid-Calf Block) for foot surgery: A pilot study  
Protocol Number: 
2022-0066 
Protocol Date: 
03/16/2022 
Sponsor: 
Department of Anesthesiology, Critical Care & Pain Management  
Principal Investigator: 
Enrique Goytizolo, MD  
Objective: 
We will investigate the duration and feasibility of a mid-calf 
block (MIDCAB) in place of the popliteal block for providing 
analgesia during foot or ankle surgery while maintaining 
motor function of the operated foot and ankle. 
Study Design: 
Prospective Cohort Study 
Enrollment: 
20 
Subject Criteria: 
1. ASA of 1 or 2 
2. Age 18-80 
3. Undergoing a foot or ankle surgery 
4.  Plan to use spinal/epidural anesthesia  
5.  Ability to follow study protocol 
Data Collection: 
Sources: EPIC, Medical Records, and Patient Report.  
Variables: Name, DOB, Race, Gender, Anesthesia Time, NRS 
Pain scores at Rest, Opioid  Consumption, Patient Satisfaction, 
PONV, Motor Function, Block Duration.   
Statistical Analysis: 
No interim analysis is planned. For continuous variable, 
descriptive statistics will be presented as means and standard 
deviations or median and interquartile ranges depending on data 
distribution. For categorical variable, descriptive statistics will be 
presented as frequencies and percentages.  

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1.0 INTRODUCTION 
 
At the present, the most widely-utilized analgesic intervention for patient receiving ankle and foot 
surgeries at HSS is the peripheral nerve block known as the popliteal nerve block which is 
performed. The popliteal block is performed on the sciatic nerve at the level of the popliteal fossa. 
Since the sciatic nerve provides sensory and motor functions to the majority of the lower leg, the 
popliteal block is a good choice for use during ankle and foot surgeries. However, the main 
disadvantage with this block is that because it’s done on the sciatic nerve which is responsible for 
motor function of most of the lower leg, the block prevents motor function of the ankle and foot for 
some time after surgery. Many studies have shown that patients participating in physical therapy 
(PT) after surgery had short hospital stays, faster ambulation and lower chances of 30-day 
readmissions. Since most patients who receive foot and ankle surgery cannot move their foot/ankle 
after surgery they will be unable to participate in PT for some time. Thus, there is an incentive to 
investigate the potential benefits of a block that would provide a s similar level of analgesia while 
allowing patients to participate in PT which will likely aid their recovery. 
 
The idea for the mid-calf block (MIDCAB) came from previous work and studies done on 
ultrasound-guided ankle blocks that have been modified. Currently these ankle blocks under 
ultrasound-guidance is performed distally, at the level of the ankle joint and foot. With this approach 
the block coverage is limited to the mid distal foot, the ankle block does not cover surgeries 
performed on the ankle joint. Instead of this, the MIDCAB block is performed proximally on the 
same nerves that are targeted with the ankle block but instead of performing it distally, it will be 
done proximally at the level of the mid-calf on the patient’s leg. Moving the probe more proximal on 
the leg will provide analgesia on the ankle joint and foot while also creating an advantage compared 
to the current standard of care at HSS, the popliteal block. 
 
MIDCAB is defined as a group of ultrasound guided distal nerve blocks at the level of the individual 
branches. The probe is placed mid-calf between the popliteal fossa and the ankle. The nerves to 
be blocked are the tibial nerve, superficial and deep peroneal nerves, sural and saphenous. Unlike 
the popliteal block, MIDCAB can provide the necessary analgesia to the foot and ankle of the 
patient while allowing them to preserve motor function of the foot. Right after surgery patients 
should be able to move their foot once the standard epidural has worn off and they should be able 
to participate in a PT sooner thus aiding their recovery. With this pilot study we are hoping to inform 
a subsequent randomized control trail (RCT) that would compare the pain scores, recovery and 
duration of the popliteal block to MIDCAB.  
1. 
Hunter Warwick, Andrew George, Claire Howell, Cynthia Green, Thorsten M. Seyler, William A. Jiranek, "Immediate Physical Therapy following 
Total Joint Arthroplasty: Barriers and Impact on Short-Term Outcomes", Advances in Orthopedics, vol. 2019, Article ID 6051476, 7 pages, 2019. 
https://doi.org/10.1155/2019/6051476 
2. 
Lakshmipathy Purushothaman, Anthony Allan, Nigel Bedforth Ultrasound-guided ankle block Continuing Education in Anaesthesia, Critical 
Care & Pain | Volume 13 Number 5 2013 
3. 
Delbos Alain Ultrasound-guided ankle block. History revisited Best Practice & Research Clinical Anaesthesiology 33 (2019) 79e93 
4. 
Girón-Arango L et al Ultrasound-guided ankle block: An attractive anaesthetic technique for foot surgery Rev Colomb Anestesiol. 
2015;43:283–289 
5. 
Nalini 
et 
al 
Role 
of 
Regional 
Anesthesia 
in 
Foot 
and 
Ankle 
Surgery 
Foot&Ankle 
Specialist 
http://www.sagepub.com/journalsPermissions.nav. 2015 
6. 
Ki Jinn Chin Ultrasound Visualization of the Superficial Peroneal Nerve in the Mid-calf Anesthesiology 2013; 118:956 MIDCAB is defined as a 
group of ultrasound guided distal nerve blocks at the level of the individual branches. 
 

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2.0 OBJECTIVE(S) OF CLINICAL STUDY 
This is a pilot observational cohort study aiming for a future randomized clinical-controlled 
trial with the objective of seeing if this MIDCAB block is a better alternative to the current 
standard of care popliteal block. We will mainly be assessing the duration of the MIDCAB 
block in patients who are undergoing foot and ankle surgery at HSS.   
The majority of patients undergoing foot and ankle procedures are given a popliteal for 
analgesia afterwards, however that block prevents patients from moving their ankle and foot 
for sometimes after surgery. The hope with MIDCAB is that patients will be able to move their 
foot after surgery while having pain relief at the same time, allowing for earlier physical 
therapy to take place and thus faster recovery time. 
We will aim to look at the following primary outcome:  
1. Block Duration (PACU, POD1, POD2 & POD7). The primary outcome will be block 
duration, how long the MIDCAB block provides analgesia. This will be measured via 
questionnaires of pain scores given to patients post surgical discharge (in PACU), 24h 
post-surgical discharge, 48 hours post-surgical discharge, and 1-week post-surgical 
discharge. Pain scores will be measured via NRS pain scale; the NRS (numeric rating 
scale) is a questionnaire that measures pain on a numeric scale, 0 (no pain) to 10 
(worst pain imaginable). We will also measure the time that pain began and the times 
that sensation of the foot returned for patients.  
We will also be looking at the following secondary outcomes:  
1. Motor Function (Measured in PACU). The return of the patient's foot/ankle motor 
function which will be measured by whether the patient can dorsiflex/plantarflex at 
the ankle or have flexion/extension of the toes. 
2. Opioid Use (PACU, POD1, POD2 & POD7). Cumulative opioid consumption in 
morphine equivalents will be recorded post-surgical discharge (in PACU), 24h post-
surgical discharge, 48 hours post-surgical discharge, and 1-week post-surgical 
discharge. 
3. Presence of Paresthesia/Numbness & Skin Irritation/Wounds (POD7). Patients will 
be asked if they have any residual numbness, skin irritation or wounds at site of 
surgery/block.  
4. Nausea & Vomiting (PACU, POD1, POD2 & POD7). The questionnaire used asks 
patients if they have experienced any nausea and vomiting, they are asked how 
many episodes of each have occurred. Patients are also asked on a scale from 0-10 
(0 being not severe and 10 being the worst severity) how severe their nausea was. 
This will be measured post-surgical discharge (in PACU), 24h post-surgical 
discharge, 48 hours post-surgical discharge, and 1-week post-surgical discharge 
 
 
 

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3.0 STUDY HYPOTHESES 
This is a pilot study aiming to assess the feasibility of MIDCAB to provide acceptable analgesia 
for foot/ankle surgery while still allowing the patient to preserve motor function of the foot and 
ankle. We hypothesize that the duration and analgesia of MIDCAB block will be non-inferior to 
the currently standard popliteal while being superior in terms of preserving motor function  
4.0 STUDY DESIGN 
 
4.1 
Endpoints 
 
4.1.1 
Primary Endpoint 
• 
The primary outcome is duration of the block. A questionnaire will be given to the 
patient before discharge from PACU, at 24 hours, 48 hours and 7 days post-op 
to measure NRS pain scores.  
 
4.1.2 
Secondary Endpoints 
o Total opioid consumption (PACU, POD1, POD2, POD7) 
o Motor function of the foot and ankle (PACU) 
o Presence of nausea and vomiting (PACU, POD1, POD2, POD7) 
o Presence of paresthesia/numbness, skin irritation/wounds (POD7)  
 
4.2 
Study Sites 
This study will take place at the main campus of the Hospital for Special Surgery (HSS). 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

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5.0 STUDY POPULATION 
 
5.1 
Number of Subjects 
20 
 
5.2 
Inclusion Criteria 
Subjects of either gender will be included if: 
1. ASA of 1 or 2 
2. Age 18-80 
3. Undergoing an ankle or foot surgery  
4. Ability to follow study protocol  
 
5.3 
Exclusion Criteria 
Subjects will be excluded from the study if: 
o Patients with the inability to understand or follow study protocol 
o Chronic opioid use (3 months or more)  
o Cannot receive neuraxial anesthesia and/or peripheral nerve block 
o Patients with contraindications to intra-op protocol (e.g., patient cannot take 
acetaminophen or ketorolac due to liver or kidney disease) 
o Patients with an ASA status of IV or higher  
o Patients intending to receive general anesthesia  
o Patients with BMI ≥ 45 
o Patients unable to communicate via telephone  
o Patients with type 2 diabetes  
o Patient refusal  
 
 
 
 
 
 
 
 

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6.0 PROCEDURES 
 
6.1 
Intraoperative Protocol (update with detailed procedure) 
 
Following patient transfer to the operating room, neuraxial anesthesia (spinal or combined 
spinal epidural (CSE) with up to 60mg mepivacaine 1.5% or up to 60mg of chloroprocaine 
2%. Sedation will be provided intraoperatively with midazolam (up to 5mg), ketorolac (up to 
30mg), famotidine (up to 20mg), along with ondansetron (4mg), dexamethasone (4mg) and 
propofol (titrated to effect). Tranexamic acid (TXA) will be dosed per surgeon request. Patient 
will be placed on a supine position with the anesthesiologist on the same side to be blocked. 
The MIDCAB block will be administered with ultrasound-guidance via a 25-gauge needle; 
30ml bupivacaine 0.5% and 4mg preservative free dexamethasone will be divided into the 
following five nerves:  
- 
Posterior Tibial nerve: probe placed posterior to the medial malleoli. Posterior tibial artery 
and posterior tibial nerve are identified. Move the probe proximally following both artery 
and nerve to the level of the mid-calf. Using a 25 G needle, 10cc of local anesthetic is 
administered with careful visualization of the local anesthetic surrounding the nerve.   
- 
Saphenous nerve: Located the saphenous vein at the level of the medial malleoli Pay 
attention to place a very gentle pressure on the probe to not collapse the vein. Follow the 
vein proximally to the level of the mid-calf. The nerve is lateral to the vein usually not seen. 
A perivascular injection at the level of the mid-calf is performed. 5 cc of local anesthetic is 
administered 
- 
Deep peroneal Nerve: Probe moves medially towards the medial border of the tibia 
between the medial and lateral maleolli. The dorsalis pedis artery is easily identified next 
to the tibia. The probe moves as proximally as possible keeping the artery in view. The 
deep peroneal nerve is most commonly found laterally to the artery at this level. 5cc of 
local anesthetic is used paying attention to perform a perivascular injection. 
- 
Superficial peroneal nerve: Moving the probe laterally the fibula is identified. Along with 
the Extensor digitalis muscle medially and the peroneus brevis laterally. The superficial 
peroneal nerve is located between the two muscles. Follow the nerve proximally to the 
mid-calf. Pay careful attention, the nerve is very superficial just deeper of the muscle 
fascia. 5cc of local anesthetic is delivered to surround the nerve.    
- 
Sural Nerve: Move the probe lateral and posterior. Identified the peroneus brevis and the 
achilles 
tendon. 
The 
short 
saphenous 
vein 
is 
also identified between 
the 
peroneus brevis and the achilles tendon. The sural nerve is usually located lateral to the 
vein.  Follow the sural nerve proximally to the level of the mid-calf. 5 cc of 
local anesthetic is administered. 
Postoperatively, all patients will receive oral dexamethasone 10mg every 8 hours (3 doses), 
intravenous ketorolac 15mg (7.5 if under 50kg) every 6 hours, and oral acetaminophen 
1000mg every 6 hours until discharged. For pain not controlled on this regimen, patients will 
be offered oral oxycodone, and intractable pain will be treated at the discretion of the provider. 
After 24 hours, patients will be transitioned to and discharged on oral meloxicam 7.5mg every 
6 hours and oral acetaminophen 1000mg every 8 hours for thirty days. The PA  or fellow 
working with the surgeon will place a discharge order for 42 oxycodone 5mg with no refills. 
Patients will be discharged with Mobic 15mg (7.5 if under 50kg) and acetaminophen 500mg. 
NRS pain scores (numeric scale 0-10) will be assessed along with motor function of the foot 
in the PACU. Additional pain score, nausea/vomiting and medication usage assessments will 
be performed on postoperative days 1, postoperative day 2 and postoperative day 7. 

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6.2 
Data Collection 
The following data will be collected: 
 
Pre-operative/Baseline 
• 
Basic demographic data 
• 
Patient weight & height, BMI 
• 
NRS scores at rest & with movement  
• 
Opioid use  
 
Intra Op Data (Operating room data) 
• 
Successful administration of block (time admin.) 
 
Pre-operative/Baseline 
• 
Length of stay in PACU 
• 
Length of stay in hospital 
 
Post-Operative Day 0 (PACU) 
• 
NRS pain scores at rest & with movement  
• 
Opioid consumption 
• 
Nausea/vomiting  
• 
Block duration/resolution  
• 
Motor function 
 
Post-Operative Day 1 (POD 1) 
• 
NRS pain scores at rest & with movement  
• 
Opioid consumption 
• 
Nausea/vomiting  
• 
Block duration/resolution  
• 
 
Post-Operative Day 2 (POD 2) 
• 
NRS pain scores at rest & with movement  
• 
Opioid consumption 
• 
Nausea/vomiting  
• 
Block duration/resolution  
 
Post-Operative Day 7 (POD 7) 
• 
NRS pain scores at rest & with movement  
• 
Opioid consumption 
• 
Nausea/vomiting  
• 
Presence of paresthesia/numbness 
• 
Presence of skin irritation or wounds  
• 
Patient satisfaction 
 
 
 
 

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7.0 STATISTICAL ANALYSIS 
The primary outcome will be the block duration and will be measured via questionnaires of pain 
scores given to the patient in PACU, as well as 24 hours, 48 hours and 7 days post-op. 
Secondary outcomes for return of motor function of the foot meaning, can the patient 
dorsiflex/plantar flex at the ankle or have flexion/extension of the toes? Other secondary 
outcomes include opioid consumption, presence of paresthesias, nausea, vomiting and the time 
needed to perform the block. No interim analysis is planned, no sample size calculation needed 
as 20 total patients will be enrolled to study the feasibility and effectiveness of MIDCAB. The is 
a pilot study and descriptive statistics will be presented for every outcome. For continuous 
variable, descriptive statistics will be presented as means and standard deviations or median 
and interquartile ranges depending on data distribution. For categorical variable, descriptive 
statistics will be presented as frequencies and percentages. 
 
8.0 ADVERSE EVENT ASSESSMENT 
All Adverse Events (AEs) will be reported in the final study report. 

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