Comparison between an Operating Surgical Microscope and High Magnification Surgical Loupes in Microvascular Reconstruction of Head and Neck Defects in a Tertiary Healthcare Centre

Abstract

Introduction and Objective

Microvascular free tissue transfers have become an important method of reconstruction following head & neck oncological resection. The objective of this study was to evaluate the efficacy of surgical loupes against surgical operating microscope, which is the gold standard for microvascular anastomosis and also to explore the possibility of surgical loupes as an essential cost-effective armamentarium in head and neck reconstruction.

Materials and Methods

This prospective randomized study included 40 patients diagnosed with head and neck malignancies, requiring microvascular free flap reconstruction. A total of 20 patients who underwent free flap reconstruction following oncologic/maxillofacial defects using high magnification surgical loupes & the other 20 patients were subjected to reconstruction under an operating surgical microscope. The efficacy was assessed based on the following parameters. 1. Total operating time taken for completing anastomosis. 2. Overall fatigue. 3. Free flap failure rate.

Results

The microscope group took an overall mean time of 34.26 min considering its limited degree of freedom in adjusting intraoperatively whereas the loupes group had a shorter mean anastomosis time 33.29 min considering its ease of operator adjustability. Overall, fatigue was compared using Mann–Whitney Test and found to be statistically significant with P value of 0.17, the loupe group was found to be better with mean score of 6.90 in 21 patients than microscope with mean score of 6.21in 19 patients. Flap survival rate in the loupe group had two cases of venous obstruction at 24 h follow-up and microscope group had 1 case of venous.

obstruction.

Conclusion

The success with loupe only free tissue transfer can be attributable considering expertise with the microscope and the loupes can be a cost-effective alternative to microscope.

Introduction

Microvascular reconstructive surgery has become an indispensable part of the treatment of tumours of the head and neck region.

Although the first free microvascular tissue transfer was reported as early as 1973 [1], there was limited enthusiasm for making use of free flaps to reconstruct head and neck defects until the late 1980s [2]. This reluctance stemmed from concerns relating to the reliability of a technique that was dependent on small-vessel anastomosis and concerns about complications and cost. Despite the enormous achievements and progress in this field regarding surgical finesse, microvascular techniques and monitoring opportunities, the success of microvascular free flap transplantation is dependent on the patient’s physical constitution. Divers impact vascular architecture and therefore presumably to affect the diseases and therapies are known negatively to influence wound healing to the success of microvascular surgical procedures.

Materials and Methods

This study was conducted at Vydehi Institute of Medical and Dental Sciences & Research Centre from the year 2018 to 2020. Patients diagnosed with head & neck malignancies, severe maxillofacial trauma & pathology requiring free flap reconstruction were included in this study. This prospective randomized study included 40 patients diagnosed with head and neck malignancies, requiring microvascular free flap reconstruction. A total of 20 patients who underwent free flap reconstruction following oncologic/maxillofacial defects using high magnification surgical loupes & the other 20 patients were subjected to reconstruction under an operating surgical microscope, resection of the primary tumour and elevation of the flap was performed simultaneously by the two surgical teams to reduce operative duration and exposure to hypothermia.

Reconstruction plates were bent intraoperatively based on the extirpated defect. Ocular loupes (× 4.5 magnification) were used for both flap elevation and microvascular anastomosis. All microvascular anastomoses were hand sutured.

The efficacy of both were compared by using the following parameters.

1. Total operating time in minutes for completion of the anastomosis.

2. Overall fatigue is measured on a fatigue scale ranging from 0 to 10 where score 0 stands for no fatigue and score 10 for worst fatigue.

3. Free flap failure rate.

Results

Forty free flap reconstructions were performed over a thirty-six-month period. Patients were randomly categorized into two groups, i.e. one group whose anastomosis was done under 4.5 × magnification ocular loupes, and another group whose anastomosis was done under standard operating microscope.

There were 11 males (52.4%) in loupes group 12(63.2%) males in microscope group and 10 (47.6%) females in loupes group and 7 females (36.8%) in microscope group (Fig. 1) with a mean age of 47.67 years in loupes group and 43.63 years in microscope group (Table 1).

Table 1.

Age and gender distribution among two groups

Variables	Category	Loupes		Microscope		P-value
		Mean	SD (%)	Mean	SD (%)
Age	Mean & SD	47.67	11.70	43.63	8.87	0.31a
	Range	32–73		32–59
		n	%	n	%
	Males	11	52.4	12	63.2
Sex	Female	10	47.6	7	36.8	0.49b

^aloupes

^bmicroscope

The majority of patients had at least one known comorbidity. Squamous cell carcinoma (SCC) was the most frequent histological diagnosis. Malignancies involving oral cavity were considered in this study. The most commonly involved structures were the buccal mucosa 13 (61.9%) in loupe group and 8(42.1%) in microscope group, central arch of the mandible 1 (4.8%)in loupe and 1(5.3%) in microscope group, posterior mandibular segmental defects 2(9.5%) in loupe group and 2 (10.5%) in microscope group and tongue 5(23.8%) in loupe group and 8(42.1%) in microscope group, respectively (Table 2).

Table 2.

Comparison of flap location between two groups using Chi-square test

Variables	Category	Loupes		Microscope		χ2 value	P-value
		n	%	n	%
Flap location	Buccal mucosa	13	61.9%	8	42.1%	1.787	0.62
	Central arch	1	4.8%	1	5.3%
	Mandible posterior segment	2	9.5%	2	10.5%
	Tongue	5	23.8%	8	42.1%

All the procedure were performed by a single surgical team. The free flaps used for reconstruction were antero-lateral thigh flap 6(28.6%) in loupe group and 8 (26.3%) in microscope group, free fibula flap 4 (19.0%) in loupe group and 4 (21.1%) in microscope group and radial forearm free flap 11 (52.4%) in loupe group and 10 (52.6%) in microscope group Table 3.

Table 3.

Comparison of flap type between two groups using Chi-square test

Variables	Category	Loupes		Microscope		χ2 value	P-value
		n	%	n	%
Flap type	ALT	6	28.6	5	26.3	0.039	0.98
	Free fibula	4	19.0	4	21.1
	RFFF	11	52.4	10	52.6

The internal jugular vein (or branch thereof) was used for the recipient vein in all cases. A vein graft was used in only one case to limit tension on the anastomosis in the case of a free fibula flap reconstruction of an extensive mandibular defects the facial artery was the most commonly recipient artery.

Anastomosis time between two groups were analysed using Mann–Whitney Test and was found to be statistically significant with P value < 0.55. The microscope group took an overall mean time of 34.26 min considering its limited degree of freedom in adjusting intraoperatively whereas the loupes group had a shorter mean anastomosis team 33.29 min considering its ease of operator adjustability. However, there was a clearer field of vision in microscope group compared to that of ocular loupes Table 4.

Table 4.

Comparison of mean anastomosis time (in mins) between two groups using Mann–Whitney Test

Variable	Groups	N	Mean	SD	Mean diff	P-value
Anastomosis time	Loupes	21	33.29	7.67	− 0.97	0.55
	Microscope	19	34.26	7.57

Overall, fatigue was measured on a fatigue scale ranging from 0 to 10 where score 0 stands for no fatigue and score 10 for worst fatigue. The proforma was handed over to the surgical team post anastomosis. The results were compared using Mann–Whitney Test and found to be statistically significant with P value of 0.17, the loupe group was found to be better with mean score of 6.90 in 21 patients than microscope with mean score of 6.21in 19 patients Table 5.

Table 5.

Comparison of mean scores for ease of use between two groups using Mann–Whitney Test

Variable	Groups	N	Mean	SD	Mean Diff	P-value
Ease of use score	Loupes	21	6.90	1.61	0.69	0.17
	Microscope	19	6.21	1.62

Flap survival rate was measured using the vascular obstruction noted over 24 to 48 h which was identified with clinical symptoms such as noticeable colour change, absence of bleeding from pin prick test and absence of warmth of flap. The loupe group had two cases of venous obstruction at 24 h follow-up and microscope group had 1 case of venous obstruction which was salvaged later. Table 6.

Table 6.

Comparison of vascular obstruction between two groups using Chi-square test

Variable	Category	Loupes		Microscope		χ2 value	P-value
		n	%	n	%
Vascular obstruction	Yes	2	9.5	1	5.3	0.261	0.61
	No	19	90.5	18	94.7

Discussion

Most malignant tumours of the head and neck cannot be adequately treated without surgical excision. Although tumour extirpation often results in better disease control and prolonged survival, patients may be left with devastating functional and cosmetic defects. Traumatic facial injuries can be similarly disfiguring and may also limit functions and aesthetics. In the last century, the aim of reconstructive techniques in the head and neck has evolved from the mere filling of a defect to the reestablishment of the patient's original appearance and function. Although the goal of modern surgical reconstruction is to obtain normal motor and other facial functions, as well as a personally and socially acceptable cosmetic result, the complex anatomy of the face and mouth presents unique technical challenges. The development of microvascular free tissue transfer during the last two decades has provided a set of techniques to overcome these difficult problems [3–5].

Capone et al. [6] reported > 75% of plastic surgeons having work-related neck and back symptoms, with a threefold higher likelihood in surgeons performing > 3 h per week of microsurgery. In the same study, symptomatic surgeons were five times more likely to develop impairment or disability during their career. Overall, fatigue in our study was measured on a fatigue scale ranging from 0 to 10 where score 0 stands for no fatigue and score 10 for worst fatigue. The proforma was handed over to the surgical team post anastomosis. The results were compared using Mann–Whitney Test and found to be statistically significant with P value of 0.17, the loupe group was found to be better with a mean score of 6.90 in 21 patients than microscope with a mean score of 6.21in 19 patients. Visual adjustment required between elevating the flap and suturing the anastomosis, narrow field of vision, lesser mobility, and ability to access difficult areas, and need for assistants to be trained to work with an operating microscope increased the operator fatigability in microscope group.

Douglas A. Ross [7] used both loupes and microscope for microvascular anastomosis and found that complication rates were almost similar in both groups and the length of the procedure was shorter in the loupe group. Similar findings were observed in our study. The time taken for anastomosis was calculated from the time post-harvesting of the flap and was calculated using the OT theatre clock. The total anastomosis time was calculated from the start of venous anastomosis till the end of the arterial anastomosis. The microscope group took an overall mean time of 34.26 min considering its limited degree of freedom in adjusting intraoperatively whereas the loupes group had a shorter mean anastomosis team 33.29 min considering its ease of operator adjustability. However, there was a clearer field of vision, zoom with depth perception in the microscope group compared to that of the ocular loupes group.

Spencer J. Stanbury studied the use of Surgical Loupes in Microsurgery. In a review of 251 free tissue transfers done with only loupe magnification, they found an overall success rate of 97.2% with a 1.2% partial flap necrosis rate, and an 8.3% revision rate for anastomoses during the initial procedure [8]. In our study, the overall success rate was determined by the vascular obstruction which was noted over 24 to 48 h and identified with clinical symptoms such as noticeable colour change, absence of bleeding from pin prick test, and absence of warmth of flap. The loupe group had two cases of venous obstruction at 24 h follow-up which could not be salvaged and pectoralis major myocutaneous flap was placed for the closure of the defect whereas the microscope group had one case of venous obstruction over 24 h which was salvaged later.

Armando De Virgilio et al. [9] conducted a study to evaluate the feasibility of microvascular anastomosis using a 4 K three-dimensional exoscope system (VITOM 3D) in 10 consecutive cases of free flap head and neck reconstructive surgery which demonstrated the technical feasibility of microvascular anastomosis. In this study, we have used a surgical loupe as a cost-effective alternative in absence of a surgical microscope for microvascular anastomosis and have found similar results.

Conclusion

Microvascular reconstruction of head and neck defects is performed using a surgical microscope, as a gold standard worldwide with use of loupes restricted for flap harvest. In a resource constrained environment use of loupes as a primary modality for both flap harvest and anastomosis has been advantageous in term of cost-effectiveness and availability of trained OT staff to handle and maintain surgical microscope.

In our study, we have been able to perform most of the reconstructions with loupes comparably to that performed under a surgical microscope. Our study is limited to head and neck reconstruction; hence, a broader perceptive of its use in other reconstruction is still debatable. However, the success of the loupe group was dependant on the surgeon’s expertise and training with microscope.